A screening assay for selecting macromolecules that interfere with the binding of a sulfated GAG to beta amyloid, the assay comprising affixing a sulfated GAG to a substrate, co-incubating the macromolecule and a known amount of beta amyloid with the sulfated GAG, determining the amount of beta amyloid bound to the sulfated GAG affixed to the substrate; wherein the macromolecule will be one which interferes with the binding of the sulfated GAG to beta amyloid.

Amyloid and amyloidosis. Amyloid is a generic term referring to a group of diverse, but specific extracellular protein deposits which all have common morphological properties, staining characteristics and x-ray diffraction spectra. Regardless of the nature of the amyloid protein deposited all amyloids have the following characteristics: 1) an amorphous appearance at the light microscopic level and appear eosinophilic using hematoxylin and eosin stains; 2) all stain with congo red and demonstrate a red/green birefringence as viewed under polarized light; 3) all contain a predominant beta-pleated sheet secondary structure; and 4) ultrastructurally amyloid usually consists of non-branching fibrils of indefinite length and with a diameter of 8-12 nm.
Amyloidosis: early historical perspectives. Rokitansky in 1842 was the first to observe waxy, eosinophilic tissue deposits in a number of tissues from different patients. However, it wasn't until 1854 when Virchow termed these deposits as "amyloid" meaning "starch-like" since they gave a positive staining with the sulfuric acid-iodine reaction, which was used in the 1850s for demonstrating cellulose. Although cellulose is not a constituent of amyloid, nonetheless, the staining that Virchow observed is probably due to the presence of different carbohydrates, known as highly sulfated glycosaminoglycans and proteoglycans, which appear to be associated with all types of amyloid deposits (see below). The name amyloid has remained despite the fact that Freiderich & Kekule in 1859 discovered the protein nature of amyloid.
Amyloid is not a single disease. For many years, based on the fact that all amyloids have the same staining and structural properties, lead to the postulate that a single pathogenetic mechanism was involved in amyloid deposition, and that amyloid deposits were thought to be composed of a single set of constituents. Current research has clearly shown that amyloid is not a uniform deposit and that amyloids may consist of different protein which are totally unrelated.
Amyloidosis is not an "immune disorder." It is interesting that the pathology textbook by Robbins has "amyloidosis" under the heading of "possible immune disorders". Obviously these authors thought like many of the predecessors studying amyloidosis in the 1960s and 1970s. This is based on a number of early observations made about amyloidosis. 1) Clinically, many types of amyloid were due to a complication of long-standing inflammatory disorders such as rheumatoid arthritis or osteomyelitis. 2) Histologically, tissue reactions in many of these disorders were characterized by the presence of immunologically competent cells (e.g. monocytes, macrophages, plasma cells. 3) Amyloid was developed in animals used for raising antisera. Repeated injections of antigens were not uncommonly followed by systemic amyloid deposits. Therefore, clinical, histological, and experimental data focused attention, not illogically, upon the immune system. However, by the mid-late 1970s, the isolation, characterization and sequencing of amyloid proteins from different clinical settings showed that a basic immunological disturbance could not account for the diversity of proteins seen as amyloids in the different diseases.
Clinical classification of amyloidosis. Let's look at how amyloid was classified initially in the mid to late 1970s and then compare it to the classification according to protein type which is used today. Basically, amyloid was clinically classified into 4 groups, primary amyloid, secondary amyloid, familial amyloid, and isolated amyloid.
Primary amyloid, is amyloid appearing de novo, without any preceding disorder. In 25-40% of these cases, primary amyloid was the antecedent of plasma cell dysfunction such as the development of multiple myeloma or other B-cell type malignancies. Here the amyloid appears before rather than after the overt malignancy. Regardless of which clinical element appeared first, the type of amyloid protein in primary amyloid is most often the same as that seen in amyloid secondary to a variety of B-cell dysfunctions.
Secondary amyloid, appears as a complication of a previously existing disorder. 10-15% of patients with multiple myeloma eventually develop amyloid. Patients with rheumatoid arthritis, osteoarthritis, ankylosing spondylitis can develop secondary amyloidosis as with patients with tuberculosis, lung abscesses and osteomyelitis. Intravenous drug users who self-administer and who then develop chronic skin abscesses can also develop secondary amyloid. Secondary amyloid is also seen in patients with specific malignancies such as Hodgkin's disease and renal cell carcinoma. Although these were all initially classified as secondary amyloid, once the amyloid proteins were isolated and sequenced, many of these turned out to contain different amyloid proteins.
The familial forms of amyloid also show no uniformity in terms of the peptide responsible for the amyloid fibril deposited. Several geographic populations have now been identified with genetically inherited forms of amyloid. One group is found in Israel, predominantly among Sephardic Jews, and this disorder is called Familial Mediterranean Fever and it is characterized by amyloid deposition, along with recurrent inflammation and high fever. Another form of inherited amyloid is known as Familial Amyloidotic Polyneuropathy, and it has been found in at least three nationalities, namely, Swedish, Portuguese and Japanese. Amyloid deposition in this disease occurs predominantly in the peripheral and autonomic nerves. Hereditary amyloid angiopathy of Icelandic origin is a autosomal dominant form of amyloid deposition primarily affecting the vessels in the brain, and has been identified in 128 members distributed in at least 8 families restricted to a small geographic area of western Iceland. These patients clinically have massive cerebral hemorrhages in early life which usually causes death before the age of 40.
The primary, secondary and familial forms of amyloid that I have so far described tend to involve many organs of the body including heart, kidney, liver, spleen, GI tract and skin.
Isolated forms of amyloid, on the other hand, tend to involve a single organ system. Isolated amyloid deposits have been found in the lung, and heart. Up to 90% of type II diabetic patients (non-insulin form of diabetes) have isolated amyloid deposits in the pancreas restricted to the beta cells in the islets of Langerhans. Isolated forms of amyloid have also been found in endocrine tumors which secrete polypeptide hormones such as in medullary carcinoma of the thyroid. A serious complication of long-term hemodialysis is amyloid deposited in the medial nerve and clinically associated with carpal tunnel syndrome. By far the most common type of organ-specific amyloid, and amyloid in general, is that found in the brains of patients with Alzheimer's disease. In this disorder, amyloid is predominantly restricted to the central nervous system (CNS). Similar deposition of amyloid in the brain occurs in Down's syndrome patients once they reach the age of 35 years. Other types of CNS amyloid deposition include rare but highly infectious disorders such as Creutzfeldt-Jakob disease, Gerstmann-Straussler syndrome and scrapie in animals.
Current classification of amyloid: by protein type. It was misleading to group the various amyloidotic disorders strictly on the basis of their clinical features since, as shown in FIG. 34, when the major proteins involved were isolated and sequenced, they turned out to be different. For example, amyloid seen in rheumatoid arthritis and osteoarthritis, now known as AA amyloid, was the same amyloid protein identified in patients with the familial form of amyloid known as Familial Mediterranean Fever. Not to confuse this issue, it was decided that the best classification of amyloid should be according to the major protein type found, once it was isolated, sequenced and identified.
AA amyloid. AA amyloid is common to a host of seemingly unrelated disorders including long-standing inflammation, various forms of malignancy, and in Familial Mediterranean Fever. Also it is the type of amyloid formed in animal models which use daily repeated injections of antigens. A potent antigen used today is casein or azocasein. In these animals, amyloid deposition occurs in the spleen, liver and kidney within 7-10 days of repeated injections.
The isolated amyloid protein in these cases turns out to be approximately 76 amino acids long, and having a MW of about 8,500. These 76 amino acids correspond to the amino terminal 2/3s of a naturally occurring serum protein known as SAA (Serum amyloid A). SAA is known to be an acute phase protein whose concentration increases about a thousand-fold, usually within 24 hours, during any inflammatory disorder. It is mainly made by the liver but current research also suggests that it can be found in other tissues as well. It's normal function at this time is not really known. The AA amyloid protein that is deposited in the tissues is identical from patient to patient, regardless of the nature of the inflammatory disorder that has preceded its deposition. The AA amyloid protein is essentially the same protein found in many other species including mice, ducks, mink and monkeys. This conservation is probably due to the important, yet unknown, role that the precursor (SAA) plays during the process of inflammation.
AL amyloid. Another major type of amyloid protein that has been identified is known as AL amyloid usually due to the deposition of the variable region of immunoglobulin light chains, either lambda or kappa chains; but it may also consist of the entire light chain. Since AL amyloid represents the variable region of light chains, AL amyloid isolated from different patients differs in its amino acid sequence. However, within a single patient the sequence of the AL amyloid protein is constant regardless of the organ from which the amyloid is isolated. This amyloid usually occurs secondary to multiple myeloma, or B-cell type malignancies (ex. immunoblastic lymphomas) and other plasma cell dyscrasias. Not all patients with multiple myeloma develop AL amyloid. Only 10-15% develop clinical problems related to these amyloid deposits, whereas a larger percent may have only microscopic deposits. Why all patients with immunoglobulin secreting abnormalities do not develop this type of amyloid is not known.
Prealbumin or transthyretin. Another type of amyloid protein that has been identified is known as prealbumin or transthyretin. Prealbumin refers not to the precursor of circulating albumin, but to the serum protein that, in standard electrophoretic separation, migrates ahead of albumin. Prealbumin or transthyretin is normally the serum carrier of thyroxine, as well as retinol binding protein and retinoic acid. It has a normal plasma concentration of 20-40 mg/dL and is synthesized by the liver, and consists of 127 amino acids. A variant protein has been found in most types of Familial Amyloidotic Polyneuropathy (FAP) both the normal and the abnormal forms of transthyretin are found in the deposits, but the latter tend to predominate. Single amino acid substitutions have been identified at positions 30, 33, 60, 77, 84, 111 and 122 of the prealbumin molecule in the circulating plasma and in amyloid deposits of FAP patients. The most common substitution is a methionine for valine at position 30 of the prealbumin molecule. It is not clear how these amino acid substitutions allow to change the metabolic characteristics of transthyretin such that it is deposited primarily in peripheral and autonomic nerves. Immunological, chemical and direct DNA tests have been developed for detection of the specific mutations in the prealbumin variants. These assays are useful in identification of family members at risk while still in the preclinical phase of the disease.
A similar prealbumin molecule is deposited in the heart in an isolated form of amyloid known as senile cardiac amyloid. This type of amyloid is a frequent postmortem finding in patients more than 80 years of age and has been generally regarded as nonspecific.
Beta2-microglobulin. Another recent type of amyloid protein which has been identified is known as beta2-microglobulin. This type of amyloid has become recognized as a serious complication of long-term hemodialysis. Its most prominent clinical presentation is the carpal tunnel syndrome. Other manifestations include joint swelling, multiple spontaneous fractures and radiolucency in the wrist and hip. Its incidence correlates mainly with the number of years spent on dialysis, usually up to 50% of patients on hemodialysis over 8-10 years develop this type of amyloid. Beta2-microglobulin is a single polypeptide chain of 100 amino acid residues and has a MW of about 11,800. Beta2-microglobulin accumulates not only in the blood of uremic patients but also in the synovial fluid and in the tissues. The pathogenesis of dialysis amyloidosis is poorly understood. Some investigators have speculated that dialysis membrane characteristics may play a role, but this is controversial.
Procalcitonin. Several forms of isolated amyloid associated with endocrine tumors have been recently described. Where there are data characterizing the protein, the amyloid is derived from a portion of the normal hormonal product secreted (or prehormone synthesized) by the cells from which the tumor arises. Medullary carcinoma of the thyroid is such an example. The tumor is related to the C-type cells of the thyroid, which normally secrete calcitonin. Immunological studies have demonstrated that the amyloid in these tumors is a fragment of procalcitonin. A variant of calcitonin has been identified as the amyloid seen in the Islets of Langerhans in patients with diabetes. Atrial natriuretic factor, or a portion thereof, is deposited in isolated atrial amyloid.
Beta amyloid protein or β/A4. Clinically the most common form of amyloidosis, is the type that is deposited in the brains of patients with Alzheimer's disease, as well as in Down's syndrome patients, usually over the age of 35. The amyloid protein deposited is now known as the beta-amyloid protein or β/A4 (due to its known MW of approximately 4,200). It is derived from a larger precursor molecule known as the beta-amyloid precursor protein. This latter protein may take on different forms, including proteins of 695, 714, 751 and 770 amino acids, since the BAPP gene produces at least four principal mRNAs through alternative splicing of two exons.
PrP protein. The last type of amyloid protein which I will discuss, which has been identified is known as the PrP protein or, PrP 27-30, due to its having a MW of 27,000-30,000. This protein is also known as the prion protein PrP 27-30 was found to be derived from a larger protein, known as PrP Sc.
These proteins are highly infectious and are transmissible. They are found in the amyloid deposits in rare neurological disease such as Creutzfeldt-Jakob Disease, Gerstmann Strausller Syndrome; and kuru.
These diseases are usually rapidly progressive neurological disorders characterized by dementia, and fall into the category of subacute spongiform encephalopathies. Microscopically, the cerebral tissue is characterized by neuronal loss, gliosis, spongiform changes and extracellular amyloid deposits in the form of plaques. This type of amyloid deposition is also seen in sheep and hamsters and is known as scrapie. Recent evidence suggests that a small nucleic acid may be present, therefore, it may be regarded as a viral form of amyloidosis.
General pathogenetic mechanisms in amyloidosis. Although amyloid deposits in all clinical conditions share common physical properties relating to the presence of a beta-pleated sheet conformation, it is now clear that many different chemical types exist and additional ones are likely to be described in the future. You may see that there are several common pathogenetic mechanisms that may be operating in amyloidosis in general. In most cases, a circulating precursor protein may result from overproduction of either intact or aberrant molecules (plasma cell dyscrasias), reduced degradation or excretion (SAA in some secondary amyloid syndromes and beta2-microglobulin in long-term hemodialysis), or genetic abnormalities associated with variant proteins (FAP). Proteolysis of a larger protein precursor molecule occurs in many types of amyloidosis, resulting in the production of lower MW fragments that polymerize and assume a beta-pleated sheet conformation as tissue deposits, usually in an extracellular location. What are the precise mechanisms involved, and the aberrant causes leading to changes in proteolytic processing and/or translational modifications is not known in most amyloids.
Proteoglycans and glycosaminoglycans in amyloidosis: a specific component of all amyloids (FIG. 35). The presence of PGs and/or GAGs associated with amyloid has been known for some time. Virchow (1854) first suggested the presence of carbohydrate in amyloid deposits, when he demonstrated positive iodine staining in organs infiltrated with amyloid indicating the presence of starch or cellulose. This material was termed "amyloid" meaning "starch-like". Friedrich and Kekule (1859) later demonstrated the protein nature of these deposits.
It was not until the late 1960s and early 1970s that the true nature of the carbohydrate present in amyloid deposits was determined. Increased amounts of GAGs (referred to as "acid mucopolysaccharides") were demonstrated in tissue from human autopsies which were infiltrated with amyloid (Berenson et al., 1969; Bitter and Muir, 1965; 1966; Dalferes et al., 1967; 1968; Mowry and Scott, 1967; Okuyara and Turumi, 1963; Pennock et al., 1968; see the appended Citations). Acid mucopolysaccharides were also described in the experimental induction of amyloidosis (Dalferes et al., 1968). Usually highly sulfated GAGs, such as heparan sulfate were increased in the amyloidotic liver and spleen of the AA and AL forms of amyloid (Bitter and Muir, 1966; Okuyara and Turumi, 1963; Pennock et al., 1968) whereas in cardiac tissue infiltrated with amyloid (i.e. senile cardiac amyloid) hyaluronic acid was shown to be the main GAG (Berenson et al., 1969). Since these studies only assessed the GAG composition in amyloid deposits obtained at end stages of the disease process (at autopsy), there was no indication of whether GAG accumulation was a primary, secondary or concurrent process with amyloid deposition. In addition the precise location of GAG accumulation in relation to amyloid deposition was also not known.
In 1985, Snow and Kisilevsky demonstrated that both highly sulfated GAGs and the amyloid protein were deposited in tissues (spleen, liver and kidney) at virtually the same time and in the exact same location using an experimental model of AA or inflammation-associated amyloidosis. In two different models of amyloid induction, neither the nature of the inflammatory inducing agent nor the length of time of the inflammatory reaction influenced the concurrent deposition of amyloid protein and GAGs. This initial study suggested that highly sulfated GAGs such as heparan sulfate, heparin and/or keratan sulfate were involved. These results indicated that the accumulation of GAGs was not a general reaction to an inflammatory stimulus but was specifically related to amyloid deposition itself. A subsequent study (Snow et al., 1987) confirmed that heparan sulfate and/or heparin were the only GAGs accumulating in the spleen in association with the AA amyloid protein. In this latter investigation plasma GAGs were found to be elevated (2-3 fold) at the time of GAG deposition in the tissues (spleen, liver). However, since most of this increase was due to chondroitin-4-sulfate, it suggested that the heparan sulfate/heparin increase observed in the tissues was probably derived from the accumulation of GAGs synthesized at the sites of amyloid deposition. Experiments using radioactive precursors for GAG synthesis demonstrated that a significant increase in GAG synthesis occurs in amyloidotic tissue in comparison to controls (Snow, unpublished data).
Although the sites of GAG synthesis in various systemic organs during amyloid deposition has not yet been identified, light microscopic (Snow et al., 1987; Snow et al., 1988) and ultrastructural (Snow et al., 1991) studies suggest that endothelial cells and/or reticuloendothelial cells may be involved. In fact, the initial accumulation of GAGs and amyloid in experimental AA amyloidosis occurs in the perifollicular sinusoids of the spleen and the walls of the central veins in the liver, two sites having a predominance of reticuloendothelial and/or endothelial cells.
Some of the first clear evidence for an intimate relationship between AA amyloid and highly sulfated PGs (such as heparan sulfate) are derived from an ultrastructural study which demonstrates positive Ruthenium red and Cuprolinic blue staining associated with amyloid fibrils in both amyloidotic spleen and liver, as well as in isolated fibril preparations (Snow et al., 1987). These cationic dyes stain sites enriched in PGs.
Recent immunocytochemical evidence confirms the histochemical results and demonstrates that heparan sulfate is specifically localized to sites of amyloid deposition in the mouse model of AA amyloidosis (Snow et al., 1991). Both an affinity-purified polyclonal antibody and a monoclonal antibody (HK-102), each recognizing specific domains on the protein core of a basement-membrane derived heparan sulfate proteoglycan (HSPG) localized HSPG core protein to the sites of amyloid deposition in both spleen and liver in experimental AA amyloidosis. In addition, a monoclonal antibody (HK-249) directed against the GAG chains of the basement-membrane derived HSPG demonstrated that the GAG chains were also localized to these same areas of amyloid deposition (Snow, Kisilevsky, Kimata, Kato and Wight, unpublished data). Furthermore, immunogold labelling at the ultrastructural level (Snow et al., 1991) demonstrated that the protein core of the HSPG was localized primarily to the amyloid fibrils which accumulate in the spleen and liver. These latter studies suggest that the heparan sulfate accumulating in the tissue concurrent with the AA amyloid protein involves deposition of both the protein core and GAG chains and is likely in the form of a HSPG proteoglycan.
The presence of highly sulfated GAGs in amyloidotic tissue, the close temporal relationship between initial amyloid deposition and PG accumulation in experimental AA amyloidosis, and the intimate ultrastructural association between AA amyloid fibrils and heparan sulfate proteoglycans, all imply that PGs may play a role in the pathogenesis of AA amyloidosis and that this role may be common to all types of amyloid. If this were true, then we would expect highly sulfated GAGs and/or PGs to be present in all types of amyloid regardless of protein type. Studies involving histochemical staining techniques employing the Alcian blue-magnesium chloride staining technique, as well as biochemical analysis, and immunocytochemical studies were used to test this hypothesis. The types of amyloid analyzed are shown in Table 1B. The results demonstrated that sulfated GAGs and/or PGs are present in close association with all these amyloids regardless of the nature of the amyloid protein deposited, the tissue or organ involved, or the extent of deposition.
Preliminary analysis involving immunohistochemical techniques using a variety of antibodies to different PG and GAG epitopes suggests that heparan sulfate proteoglycans are present in human AA and AL amyloid deposits in a number of different organs within the same individual (Snow, Benditt, Kimata, Kato, Hassell and Wight, unpublished data) suggesting that this particular highly sulfated proteoglycan may be involved in amyloid deposition independent of the nature of the amyloid protein involved and the type of organ or tissue in which the deposition occurs.
Possible role(s) of proteoglycans in the pathogenesis of amyloidosis. One possible general role that the highly anionic PGs such as heparan sulfate may play in amyloidosis, is to influence different amyloidogenic proteins to form similar beta-pleated sheet structures and demonstrate similar morphological (i.e. fibrillar structure), staining (Congo red and Thioflavin S positive) and spectral characteristics. The ability of PGs/GAGs to influence amyloid fibril formation can be analogous to its role in collagen fibrillogenesis where the presence of PGs/GAGs in the early stages of collagen fibril formation determined the rate and the size of the fibril formed (Gelman and Blackwell, 1974a; 1974b; 1974c). Further studies are needed to determine which GAGs and/or PGs (if any) influence the conformation of other amyloidogenic proteins such as the beta-amyloid precursor in Alzheimer's disease, the PrP protein in the prion diseases, or the immunoglobulin light chains in AL amyloid.
Although it is feasible that highly sulfated PGs may play a role in the conformational folding of precursor amyloidogenic proteins into amyloid fibrils, many investigators would argue that PGs have nothing to do with amyloid fibril formation. This is due to the fact that a number of studies have shown that intact amyloid proteins (i.e. beta2-microglobulin) and/or synthetic peptides to portions of amyloid proteins (i.e. A4) can adopt a beta-pleated sheet conformation and polymerize as fibrils in vitro (Conners et al., 1985; Glenner et al., 1971). These studies include the formation of amyloid-like fibrils in vitro from immunoglobulin light chains (AL amyloid) (Glenner et al., 1971), beta2-microglobulin (Conners et al., 1985) and synthetic peptides corresponding to portions of the A4 amyloid protein (Castano et al., 1986; Gorevic et al., 1987; Kirschner et al., 1987). However, diverse conditions and treatments appeared necessary for amyloid fibril formation to occur, including a progressive decrease in salt concentration for beta2-microglobulin (Conners et al., 1985) and enzymatic digestion in an acidic environment for light chains of immunoglobulins (Glenner et al., 1971). In addition, in some instances, properties of the formed synthetic amyloid fibrils were somewhat different that those found in vivo. For example, the synthetic amyloid fibrils formed from synthetic peptides to various regions of the A4 protein could be completely solubilized whereas isolated amyloid fibrils from brain tissue is known to be very insoluble and tends to aggregate. Further studies are needed to determine whether the type of self-aggregation which can occur in vitro under a number of different conditions with various amyloidogenic proteins and synthetic analogues is actually the mechanism operating in vivo at the sites of amyloid formation.
A second possible role of highly sulfated proteoglycans in amyloidosis may be in determining the anatomical location of amyloid deposition. During the experimental induction of amyloid (i.e. AA amyloidosis, amyloid plaque formation in the scrapie hamster model), it is not known why the deposition of amyloid always occurs in precise anatomical sites (i.e. perifollicular area of spleen and in walls of central veins in liver, subependymal localization in scrapie hamster model). Likewise, clinically, certain types of amyloid are always found in specific organs or locales as opposed to other types of amyloid. Examples include senile cardiac amyloid in the heart, amyloid plaques in the hippocampal region in Alzheimer's disease and amyloid confined to the peripheral and autonomic nervous system in familial amyloidotic polyneuropathy. If highly sulfated PGs and/or GAGs are important in determining the location of amyloid deposits then it is possible that the PGs and/or GAGs are present in tissue locations prior to the deposition of amyloid to these sites. Although it is difficult to determine whether the association of PGs/GAGs to areas of amyloid deposits occurs as a primary or secondary event, evidence to suggest that they are deposited early during amyloid formation comes from a number of studies. In experimental AA amyloidosis, time course studies have demonstrated that highly sulfated GAGs (now identified as HSPGs) and the AA amyloid protein are deposited at virtually the same time and in the same locale (Snow and Kisilevsky, 1985; Snow et al., 1991). In Alzheimer's disease, immunocytochemical studies have demonstrated that HSPGs are present in "primitive plaques" (Snow et al., 1988). These plaques, containing essentially no amyloid component, are believed to be the precursor form of the mature plaque which contains an abundance of amyloid localized to a central core. Time-sequence analysis of initial β/A4 and HSPG deposition in different aged patient's with Down's syndrome indicate that HSPG accumulation in association with β/A4 may occur prior to the formation of fibrillar amyloid (Snow et al., 1990a), suggesting an important early role for HSPGs in the pathogenesis of β/A4 formation and/or deposition.
Another possibility that may be important in determining the location of amyloid deposits is that PGs have a strong binding affinity with possible amyloidogenic precursor proteins and/or the amyloid proteins themselves. As previously discussed, HSPGs appear to have a strong binding affinity for both the AA amyloid protein and the β/A4 amyloid protein (Snow et al., 1989) which may be important in the ultimate deposition of these amyloidogenic proteins to specific sites containing increased amounts of HSPGs. The preferential binding of PGs to specific proteins is not a new concept. For example, it has been known for some time that particular PGs interact with the protein moiety of beta-lipoproteins (Camejo, 1982).
A third possible role of highly sulfated PGs in the pathogenesis of amyloidosis, regardless of whether the accumulation of PGs in amyloid deposits occurs as a primary or secondary event, may involve PGs contributing to the insolubility of amyloid and its inaccessibility to proteolytic degradation in tissues. Amyloid deposits once established in various organs and tissues are very stable and usually stay in these sites over long periods of time without significant change (Franklin, 1972; Glenner and Page, 1976). Both experimentally and clinically, few methods have been successful for the removal of amyloid deposits once formed. In this same context, the association of PGs and/or GAGs with the amyloid protein in the neuritic plaques and the components of neurofibrillary tangles in Alzheimer's disease may contribute to the insolubility problems investigators have had in trying to isolate and sequence amyloid proteins (Gorevic et al., 1986; Iqbal et al., 1984). The presence of PGs at the sites of amyloid deposition may also be involved by interacting with proteases and/or protease inhibitors (i.e. alpha1-antichymotrypsin) (Abraham et al., 1988) which may lead to the prevention of amyloid degradation once formed. An analogous situation has been recently reported (Saksela et al., 1988) in which endothelial cell-derived heparan sulfate was found to protect basic fibroblast growth factor from proteolytic degradation.
It is interesting to speculate that in Alzheimer's disease specific alterations in PG metabolism (i.e. synthesis and/or degradation) may occur in the brains of patients afflicted with this disease. It is even possible that the primary defect in Alzheimer's disease may actually be a defect directly or indirectly affecting PG metabolism which is only apparent in some individuals with aging and/or the presence of an unknown environmental stimulus. This PG defect could be residing in a subpopulation of cells and may contribute to the accumulation of PGs only within specific areas of the brain (i.e. in pyramidal neurons in the hippocampus). This may help explain the "selective vulnerability" of neurons that are affected in Alzheimer's disease. It is important to note that changes in the sulfation and/or polymerization of neuronal GAGs may occur in the brain as a function of aging. This may be necessary for the formation and/or accumulation of plaques and/or tangles that are observed even in aged non-demented individuals.
Alzheimer's Disease, amyloid precursor proteins and the β/A4 peptide. The characteristic and diagnostic feature of brains of individuals with AD is the deposition and accumulation of a 39-43 amino acid peptide (Mr˜4,200) termed the beta-amyloid protein (Glenner and Wong, 1984; Wong et al., 1985), A4 (Masters et al., 1985) or β/A4 (Beyreuther and Masters, 1990). This small peptide is a major component within the amyloid deposits of neuritic plaques and in the walls of blood vessels (i.e. congophilic angiopathy) in the brains of patients with AD, and is derived from larger precursor molecules (termed beta-amyloid precursor protein or APP) by an unknown pathogenic mechanism. APP is composed of 3 major isoforms, APP695, APP751, and APP770, which arise by alternative splicing of a single gene (Kang et al., 1987; Kitaguchi et al., 1988; Ponte et al., 1988). APP751 and APP770 contain a protease inhibitor domain (Ponte et al., 1988; Kitaguchi et al., 1988). The normal function of the APP is not known but some have speculated that it may play a role in neuronal adhesion (Lang et al., 1987), and/or neuronal growth and regulation (Whitson et al., 1989; Saitoh et al., 1989). APP contains an extracellular amino-terminal domain, a single transmembrane domain, and a short cytoplasmic segment. The sequence of β/A4 includes the first 28 residues of the extracellular domain and 11-14 residues of the proposed transmembrane domain. Recent studies (Sisodia et al., 1990; Esch et al., 1990) indicate that during normal APP catabolism the intact amyloidogenic fragment containing the β/A4 is not generated, due to proteolytic cleavage at or near position 612 of APP (Lys-16 of β/A4), resulting in the release of a soluble secreted protein of undefined function. These latter studies also suggest that altered APP processing is required to release the β/A4 domain found as a major component of fibrillar amyloid deposits.
Proteoglycans and glycosaminoglycans. Proteoglycans are a group of complex macromolecules which are found in all organs and tissues, intracellularly in a variety of different cell types, or extracellularly in the matrix where they are exported for a variety of functions (Gallagher et al., 1986; Hascall and Hascall, 1981; Poole, 1986; Ruoslahti, 1988). Proteoglycans consist of a protein core to which one or more GAG chains are covalently linked through o-glycosidic linkage to serine residues in the core protein (Hascall and Hascall, 1981; Hassell et al., 1986). The highly anionic GAG chains consist of repeating disaccharide units, containing 1) hexosamine (either D-glucosamine or D-galactosamine) and 2) hexuronic acid (either D-glucuronic acid or L-iduronic acid) (Muir, 1969). Specific disaccharide repeat patterns give rise to 7 different types of GAGs. These are hyaluronic acid, chondroitin-4-sulfate, chondroitin-6-sulfate, dermatan sulfate, heparan sulfate, heparin and keratan sulfate. Usually one type of GAG predominates on a single core protein, giving rise to four major families including chondroitin sulfate proteoglycan (CSPG), dermatan sulfate proteoglycan (DSPG), heparan sulfate proteoglycan (HSPG) and keratan sulfate proteoglycan (KSPG). However, more than one type of GAG can be inserted on the same core protein giving rise to "hybrid PGs". The core proteins of the PGs have been the least well studied. However, a number of cDNAs have been cloned and the partial or complete amino acid sequence of some of these have been deduced (ourdon et al., 1985; Day et al., 1987; Doegle, 1986; 1987; Krusius et al., 1987) including the complete amino acid sequence for the BM-HSPG (known as "perlecan") in both mouse (Noonan et al., 1988; 1991) and human (Kallunki and Tryggvason, 1992; Murdoch et al., 1992).
The diversity of PGs largely derives from the number of different protein cores within each PG family and from the polydiversity produced by a number of post translational modifications required to construct the final molecules. This structural diversity may account for the multiple properties of these complex molecules.
Specific proteoglycans in amyloidogenesis. Specific PGs such as the HSPG, together with the amyloid P component (Coria et al., 1988; Holck et al., 1979) are the only macromolecules consistently associated with all varieties of amyloid irrespective of the type of amyloid protein present or its location (Snow and Wight, 1989b). It is likely that some components involved in amyloid formation, deposition and accumulation are not unique to only one type of amyloidosis (i.e. the β/A4 of AD), but play a role in the pathogenesis of other types of amyloid as well (i.e. AA or inflammation-associated amyloid, AL amyloid involving the deposition of immunoglobulin light chains; transthyretin in familial amyloidotic polyneuropathy). A common mechanism may help explain why different types of amyloid (i.e. consisting of different amyloid proteins) all form similar beta-pleated sheet structures with similar morphological (i.e. fibrillar structure), staining (Congo red and Thioflavin S positive), and spectral characteristics.
One general role that the highly anionic PGs may play in amyloidosis is to influence different amyloidogenic proteins to form similar beta-pleated sheet structures. The ability of PGs and GAGs to influence amyloid fibril formation might be analogous to their role in collagen fibrillogenesis where the presence of PGs and GAGs determines the rate and the size of the fibril formed (Katz et al., 1986; Mathews and Decker, 1968; Obrink, 1973; Vogel et al., 1984). Evidence that highly sulfated GAGs can influence protein folding comes from in vitro circular dichroism studies which demonstrated that different GAGs can exert a direct influence on the conformational folding of various mixed and homologous polypeptides (Gelmann and Blackwell, 1973; 1974). Recent studies (McCubbin et al., 1988) demonstrate that heparan sulfate (and not heparin or chondroitin-6-sulfate) influences the specific AA amyloid precursor, known as SAA2 to form a predominant beta-pleated sheet structure. This study implicates heparan sulfate in conformational alterations of amyloidogenic precursors which may be important in the ultimate formation of the beta-pleated sheet structure characteristic of all amyloids.
The distribution of particular proteoglycans may also specifically direct the anatomical location of amyloid deposition. If so, then PGs and/or GAGs may be present in tissue locations prior to the deposition of fibrillar amyloid at these sites. Although it is difficult to establish definitively whether the association of PGs/GAGs with amyloid deposits occurs as a primary or secondary event, evidence to suggest that PGs/GAGs are deposited early or concurrent with amyloid formation comes from a number of studies (Snow et al., 1988b; Snow et al., 1990). For example, in experimental AA amyloidosis, time course studies have demonstrated that HSPGs and the AA amyloid protein are deposited at virtually the same time and in the same locale (Snow and Kisilevsky, 1985; Snow et al., 1988b).
Regardless of whether the accumulation of PGs in amyloid deposits occurs as a primary or secondary event, PGs may contribute to the stability of amyloid and its inaccessibility to removal or proteolytic degradation in tissues. The presence of PGs at the sites of amyloid deposition may inactivate proteases and/or activate protease inhibitors (i.e. alpha 1-antichymotrypsin) (Abraham et al., 1988), which may prevent amyloid degradation. Recent studies have demonstrated that endothelial cell-derived heparan sulfate protects basic fibroblast growth factor from proteolytic degradation (Saksela et al., 1988). It is postulated that the basement membrane derived HSPG once bound to β/A4 prevents its normal degradation by proteases.
Heparan sulfate proteoglycans and their potential role in β/A4 amyloidogenesis. Although there are potentially many different types of PGs and/or GAGs that can be synthesized by cells, both within and outside the CNS, accumulating evidence suggests that only the HSPG class is localized to a variety of different amyloids (Snow et al., 1988a; 1988b; 1989). The specific association of HSPGs with a variety of different amyloids suggests that the HSPG-amyloid association is more than simply a charge effect since similarly charged PGs such as keratan sulfate do not appear to be present in association with different amyloid proteins (Snow and Wight, 1989). Immunocytochemical evidence indicates that it is the basement membrane derived HSPG (i.e. perlecan) which is associated with a variety of different amyloids (Snow et al., 1988a; 1988b; Snow and Wight, 1989). The deduced amino acid sequence of the core protein of this particular PG is known from the analysis of corresponding cDNA sequences in both mouse (Noonan et al., 1988; 1991) and human (Kallunki and Tryggvason, 1992; Murdoch et al., 1992), and the gene for this HSPG is localized to chromosome 1 in both of these species (Wintle et al., 1990).
As described above, recent studies (Esch et al., 1990; Sisodia et al., 1990) imply that other amyloid components may be necessary and involved in post-translational modifications of the APP, ultimately leading to the accumulation of the β/A4 fragment. One such component may be the basement membrane derived HSPG. Our previous studies have shown the accumulation and co-localization of a specific HSPG to the amyloid deposits containing β/A4 in neuritic plaques and amyloidotic blood vessels in AD and Down's syndrome brain (Snow et al., 1988a; 1989; 1990). Immunohistochemical (Snow et al., 1988; Snow and Wight, 1989) and cationic dye studies (Snow et al., 1989; Young et al., 1989) indicate an intimate ultrastructural association between this particular PG and amyloid fibrils containing the β/A4.
In Down's syndrome, evaluation of brains from patients aged 1 day to 51 years demonstrated initial co-accumulation of both HSPG and β/A4 in diffuse cortical deposits in 18 and 24 year old patients. These deposits were congo red and thioflavin S negative and were believed to be the precursor to fibrillar amyloid formation which was observed in Down's syndrome patients over the age of 35 years (Snow et al., 1990). This observation rules against the possibility that PGs accumulate in amyloid simply as a common response to the presence of amyloid fibrillar deposits.
Potential animal models of Alzheimer's Disease. Early animal models of AD focused upon the neurochemical and anatomic pathology of the disease and attempted to mimic this pathology with lesions in animals. One of the first models focused on the cortical cholinergic system which is profoundly affected in AD (Perry et al., 1977; Davies and Maloney, 1978). Whitehouse et al. (1982) reported that the cells of origin of the cortical cholinergic fibers, located in the nucleus basalis, were substantially depleted in AD. This led to a large number of studies examining the effects of nucleus basalis lesions in rats and other species on behavioral and neurochemical indices. These lesions were widely reported to induce memory deficits for a number of tasks (Flicker et al., 1983; Helper et al., 1985; Kesner et al., 1986). Some normally aged rats have spontaneous loss of nucleus basalis cholinergic neurons, and this loss is correlated with memory dysfunction (Bartus et al., 1982). Fisher et al. (1987) found that intraventricular nerve growth factor infusions could reverse the cholinergic neuron atrophy and restore memory function in these aged rats. This finding, among others, has led to the suggestions that nerve growth factor (NGF) may be therapeutically beneficial in AD (Hefti et al., 1989). Arendash et al. (1987) reported that the long term effects (14 months postlesion) of nucleus basalis lesions caused the formation of plaque-like and fibrillar structures in rat brain, and resulted in neuron loss in cortex, hippocampus and amygdala. Surprisingly, additional reports characterizing this model of AD have not appeared over the last 5 years.
In spite of the Andendash et al. (1987) report, most view the cholinergic deficits as a critical component, but not the major dysfunction in AD. Some researchers have raised doubts about the role of basal forebrain cholinergic neurons in memory dysfunction (Wenk et al., 1986). Others suggest that the nucleus basalis neuron atrophy in AD may be secondary to cortical degeneration, because cortical lesions in rats and monkeys can lead to shrinkage of these cells (Sofroniew et al., 1983; Pearson et al., 1983). A second lesion model receiving some attention is lesions in entorhinal cortex. Hyman et al. (1984) recognized that loss of projection neurons from the entorhinal cortex to the hippocampus was a prominent feature in AD, which, together, with the subicular neuron loss, functionally isolated the hippocampus from the rest of the brain. Entorhinal lesions in rats have long been studied as a model system for synaptic sprouting within the denervated hippocampus. Geddes et al. (1986) have reported remarkable similarities in the hippocampus between neurochemical and anatomical changes in AD and those following entorhinal lesions in rats, and suggest that reactive synaptogenesis may play a critical role in amyloid plaque formation. However, one problem with most lesion models of AD is that they ultimately may mimic some of the end stage pathology of the disease, and not the pathogenesis of the disease.
Another potential animal model of AD is normal aging. Several species develop β/A4 immunoreactive amyloid plaques including dogs (Ishihara et al., 1991), non-human primates (Selkoe et al., 1987; Martin et al., 1991), and polar bears (Cork et al., 1988). One problem with these models is that the amyloid plaques usually occur in late life in these animals, precluding rapid screening of potentially therapeutic substances or interventions. One advantage of the rat model described in this patent application is the rapid production (within 1 week) of β/A4 amyloid deposits in brain. Interestingly, Vaughan and Peters (1981) reported that aged Sprague-Dawley rats (28 and 30 months old) possess congophilic amyloid plaques that ultrastructurally resemble the material found in AD. Surprisingly, these data have not been widely discussed in other reports.
More recently, transgenic mice have been produced as potential models of AD. The rationale for these models is that overproduction of an APP transgene (containing all or part of the APP sequence) could lead to the eventual development of β/A4 deposits in mouse brain and subsequent plaque formation. Wirak et al. (1991) generated transgenic mouse lines containing the β/A4 sequence under the control of the human APP promoter. After 1 year, these mice developed β/A4 deposits within hippocampal neurons and formed aggregates of amyloid-like fibrils. Quon et al. (1991) used a full length APP751 (Kunitz protease inhibitor containing form) sequence linked to a neuron-specific enolase promoter. Transgenic mice with this construct displayed extracellular β/A4 immunoreactive deposits, which were infrequently stained with thioflavin S, but not by congo red, suggesting a pre-amyloid like composition. Kawabata et al. (1991) developed transgenic mouse lines massively overexpressing a construct encoding the C-terminal 100 amino acids of APP under control of a Thy-1 element. These mice displayed pathology remarkably similar to that observed in AD including amyloid plaques, neurofibrillary tangles and neurodegeneration in hippocampus, neocortex and even cerebellum. While extremely promising, the report by Kawabata et al. (1991) has been retracted whereas the study by Wirak et al. (1991) has been questioned (Jucker et al., 1992). Additional research will determine if the overexpression of APP is sufficient to produce the neuropathological features of AD. While more rapid than aged animal models, these models still suffer from the requirement of several months delay before AD-like pathology may develop.
The last type of animal models all involve injecting or transplanting materials into brain parenchyma. Richards et al. (1991) grafted fetal hippocampus from trisomy 16 mice into congenic normal mice and observed intracellular staining for APP, β/A4, neurofibrillary tangles, tau protein and ubiquitin immunoreactivity, within the graft, but not in host tissues. However, no extracellular β/A4 deposits resembling amyloid plaques were reported. Trisomy 16 mice contain an additional APP gene, analogous to Down's syndrome patients (human trisomy 21), who develop amyloid plaque and neurofibrillary tangle pathology similar to that observed in AD. A second model using parenchymal injections was described by Kowall et al. (1991). These authors acutely injected β/A4 (140) into rat hippocampus and observed substantial neuronal loss and induction of ALZ-50 antibody immunostaining within 1 week. These effects were attenuated by coadministration of substance P either centrally or peripherally. Importantly, no apparent congophilic amyloid deposits was observed. A final animal model involved acute injections of purified AD amyloid plaque cores into rat cortex or hippocampus (Frautschy et al., 1991). At 1 month, but not 1 week, ALZ-50 and ubiquitin staining and neuronal degeneration was evident in 70% of the rats. As expected, these amyloid cores isolated from AD brain remained congophilic after residing in rat brain for 1 month. It is important to note that SDS-extracted amyloid cores from human AD brain still contain immunoreactivity for HSPGs (Snow et al.) suggesting that in this latter study, besides undefined components in the isolated plaque cores, HSPGs and β/A4 were present.
Each of the animal models described above possess specific features making them valuable for AD research. However, each has some disadvantages. The specific advantages of our model include 1) the deposition of congophilic β/A4 amyloid in rat brain at selected sites, 2) the model is rapid with some features present as early as 1 week (although neurodegenerative effects may require longer incubations as in Frautschy et al. (1991)), 3) the injected materials consists of defined components enabling one to determine the effects of each component individually (by infusing them separately or in different concentration ratios), and 4) by continuous infusion we are able to deposit into brain larger quantities of material than by acute injections.

Screening assay for macromolecules that inhibit binding of sulfated glycosaminoglycan to beta amyloid


A torque converter is provided with a front cover (2) at the power input side, an impeller, a turbine (4), a stator (5), a piston (22), a plate spring (35), and a friction facing (36). The piston (22) is disposed in the space formed between the front cover (2) and the turbine (4) to divide the space into first and second hydraulic chambers (A) and (B). The first hydraulic chamber (A) is located between the piston (22) and the front cover (2), while the second hydraulic chamber (B) is located between the piston (22) and the turbine (4). The piston (22) can move close to and away from the front cover (2) by the pressure difference between the first hydraulic chamber (A) and the second hydraulic chamber (B). The piston (22) is opposite the front cover (2) and engages to the turbine (4) to enable the torque to be transmitted. The plate spring (35) is fixedly coupled to the piston (22) and is opposite the front cover (2). The friction facing (36) is fixedly coupled to the plate spring (35) and is located adjacent to the front cover (2). In the state where the piston (22) is disposed closest to the turbine (4), and at least when substantially no pressure difference exists between the first and second hydraulic chambers (A) and (B), the friction facing (36) is pressed against the front cover (2) by the plate spring (35) to increase the moving speed of the piston (22) when the lock-up clutch (7) of a torque converter (1) being engaged.

1. Field of the Invention
This invention generally relates to a torque converter. More specifically, the present invention relates to a torque converter having a lock-up clutch installed therein.
2. Background Information
Torque converters usually include a fluid coupling mechanism for transmitting torque between the crankshaft of an engine and the input shaft of an automatic transmission. In recent years, to improve fuel efficiency, some torque converters have included lock-up devices that, upon reaching predetermined operating conditions, lock-up the torque converters so that power from the crankshaft of an engine is directly transmitted to the automatic transmission, bypassing the fluid coupling device. Upon engagement, lock-up devices often cause a shudder, or vibration. Further, while engaged, the lock-up device is subject to vibrations caused by sudden acceleration, or deceleration, or other vibration including circumstances associated with internal combustion engines. Consequently, a torsional vibration dampening apparatus is typically employed in a lock-up mechanism to dampen vibration.
A torque converter has three types of runners (impeller, turbine, stator) located inside for transmitting the torque by means of an internal hydraulic oil or fluid. The impeller is fixedly coupled to the front cover that receives the input torque from the power input shaft. The hydraulic chamber formed by the impeller shell and the front cover is filled with hydraulic oil. The turbine is disposed opposite the front cover in the hydraulic chamber. When the impeller rotates, the hydraulic oil flows from the impeller to the turbine, and the turbine rotates. As a result, the torque is transmitted from the turbine to the main drive shaft of the transmission.
The lock-up clutch is disposed in the space between the front cover and the turbine. As mentioned above, the lock-up clutch is a mechanism to directly transmit the torque between the crankshaft of the engine and the drive shaft of the transmission by mechanically coupling the front cover and the turbine. The lock-up clutch includes primarily a piston and an elastic coupling mechanism to connect the piston to the members on the power output side of the turbine. The piston is disposed to divide the space between the front cover and the turbine into a first hydraulic chamber on the front cover side and a second hydraulic chamber on the turbine side. As a result, the piston can move close to and away from the front cover by the pressure difference between the first hydraulic chamber and the second hydraulic chamber. A friction joining member covered by friction facing is formed on the outer periphery of the front cover on the axial surface facing the piston. When the hydraulic oil in the first hydraulic chamber is drained and the hydraulic pressure in the second hydraulic chamber increases in pressure, the piston moves toward the front cover side. This movement of the piston causes the friction facing of the piston to strongly press against the friction surface of the front cover.
The elastic coupling mechanism functions as a torsional vibration dampening mechanism to dampen vibration in the lock-up clutch. The elastic coupling mechanism includes, for example, a drive member fixedly coupled to the piston, a driven member fixedly coupled to the turbine side, and an elastic member, such as one or more coil springs, disposed in between the drive member and the driven member to enable torque transmission.
When the lock-up clutch is engaged, the hydraulic oil in the first hydraulic chamber is drained from its inner circumferential side and the hydraulic oil is supplied to the second hydraulic chamber. As a result, the hydraulic pressure in the second hydraulic chamber becomes greater than the hydraulic pressure in the first hydraulic chamber. This pressure differential between the first and second hydraulic chambers causes the piston to move toward the front cover. During the movement of the piston, the hydraulic oil in the second hydraulic chamber sometimes flows through the gap between the friction facing and the friction surface of the front cover into the first hydraulic chamber. In this case, the hydraulic pressure in the second hydraulic chamber does not become large enough, and the moving speed of the piston becomes slower.
In view of the above, there exists a need for a torque converter, which overcomes the above mentioned problems in the prior art devices. This invention addresses this need in the prior art as well as other needs, which will become apparent to those skilled in the art from this disclosure.

Torque converter with lock-up clutch having a flow-restraining elastic friction member


The present invention permits registry settings and other pertinent shared artifacts to be distributed across many different computing devices. More specifically, the invention permits applications installed on an external drive to be activated, when the external drive is connected to a main computing device. When connected, a drive agent can detect registry settings stored on the external drive and can synchronize these settings with a main registry of the main computing device. Further, interface elements, such as icons for the new applications can be added to a GUI of the main computing device. Once the registry settings are included in the main registry, applications on the external drive can used from the main computing device. When the external drive is detached from the main computing device, the device agent can automatically remove all registry settings, shared artifacts, and interface elements.

1. Field of the Invention
The present invention relates to the field of device access and, more particularly, to an automated solution to provide immediate requisite access to data and applications on an attached external device.
2. Description of the Related Art
Advances in portable hard drives and flash drives permit users to easily carry a tremendous amount of convenient storage space when traveling, which could in theory be used to satisfy their data and application needs. At present, however, portable storage devices are only useful for storing data and are unable to store applications that consume or manipulate the data. This is because use of most modern applications requires a set of Application Program Interfaces (APIs), Dynamic Link Libraries (DLLs), registry settings, and the like, which are stored on a main drive of an operating system at application installation time. Consequently, data can be transported on external drives, but is often unable to be used because access to a necessary and corresponding application is unavailable.
A wide variety of solutions have been developed to ensure users have access to needed applications. One attempted solution is to continuously install and uninstall application programs, such as from images stored on the portable drive. This solution has many flaws. First, users are often not granted access to install programs on public use machines, such as those found at libraries, internet cafés, and airports. Further, constantly installing and removing programs is a practice that corrupts a registry and shared library stores, is time consuming, and may even be impossible due to computer specific hashes used to "activate" many software programs.
One technique that could minimize some of the flaws with repetitive install and uninstall operations is application virtualization. Commercial application virtualization solutions are currently provided by companies such as Atiris, Inc., Softricity Inc., and AppStream Inc. Application virtualization creates a virtual application layer between an operating system and an application. This layer is activated when a program is installed. The virtual application layer functions as a proxy between a registry and an installed application, where application specific settings are placed in the virtual application layer. If an application is moved from one machine to another that includes the same virtual application layer, machine-specific settings do not have to be adjusted. In order for a virtualized application to execute, the application virtualization layer first needs to be executing.
This solution fails to overcome problems involving insufficient permission to install applications. Permission problems are actually increased, since creating a new application virtualization layer on a machine is a very intrusive process typically requiring system administrator privileges. Further, application virtualization fails to address situations of executing applications from a periodically removed external drive. When the drive is present, necessary application programs can exist. When removed, these programs will be absent, creating problems and errors when an associated icon or shortcut is selected.
A traditional solution to ensuring application availability is to create an application server on the network that allows a multitude of users to access an application. However, the application server is only accessible when a user is connected to the network. Thus, the issue of needing additional hardware and software to overcome the distance resurfaces in order to provide a remote user with access. Further, network latency issues can result in application performance that is below an acceptable level. This can be especially true when a traveler is accessing a served application over a low quality network connection.
In addition to issues of hardware and performance, current software licensing practices are a precarious quagmire of issues relating to applications. Most commercial software requires a license and/or activation for each installation of the application, whether or not the additional installation is for the same user. A user can easily consume multiple licenses in order to accommodate an assortment of devices that are necessary to provide them access in a variety of locations and situations. For example, a user may need a license for a work computer, a home computer, a laptop computer, and the like. Conventional solutions working with the current licensing system severely limit a user and a company in terms of portability and affordability.

Automated solution to provide personalized user environment on any public computer using portable storage devices with personalized user settings uploaded to local registry of public computer

International Business Machines Corporation


Disclosed is a treated material including a base material such as an extrudate, a woven fabric, or unwoven fibers, a disperse dye-type molecule such as a dye or antibiotic dispersed within and non-covalently adhered to the base material, and a molecule-of-interest immobilized on the base material by way of a reactive group on the disperse dye-type molecule. Also disclosed are methods of producing the treated material.

The technical field of the present invention is the treatment of natural and artificial materials, and more specifically involves the use of dyes and antibiotics as binding agents for the adherence of preselected molecules to surfaces of natural or artificial materials useful in medical prostheses and in the fabric industry.
The use of artificial or processed natural materials in medical devices and prostheses implanted in the body, or placed in contact with body components, or placed in contact with medicants to be introduced into the body, often poses problems such as, for example, infection in the presence of prosthetic materials, or lack of long term thromboresistance. Thus, the surfaces of medical devices have been treated in an effort to enable or enhance their proper functioning. For example, implantable vascular prostheses made of artificial materials have been treated with biologically active molecules having thrombolytic, anticoagulating, thrombogenesis-inhibiting, and/or platelet inhibiting abilities so as to improve on their thromboresistance (see, e.g., Salzman et al. (1987) in Hemostasis and Thrombosis: Basic Principles and Clinical Practice. 2nd Ed., (Colman et al., eds. , Lippincott Co., Phila., Pa., pp. 1,335-1,347; Kusserow et al. (1971) Trans. Am. Soc. Artif. Intern. Organs 17:1); and Salyer et al. (1971) Medical Applications of Plastics, Biomed. Materials Res. Sym. Gregor, ed.) No. 1 pp. 105).
The attachment of biologically active molecules to artificial substances has proven in many instances to be difficult. For example, the attachment of various thrombogenesis inhibitors directly to solid surfaces in many instances does not result in a stable adherence or long term blood compatibility. Furthermore, the biological activity of the molecule may be compromised by virtue of the mode of attachment.
Therefore, what is needed are new or improved methods of adhering molecules of interest to material surfaces which result in a stable linkage and little loss of activity.
One method of improving on the longevity and effectivity of the linkage is to bind the biologically active molecule to a base coat layer on the material surface, where the base coat layer includes a component having multiple attachment sites available to the biologically active molecule (see U.S. Pat. Nos. 5,019,393 and 5,126,140). By way of example, the base coat layer may be adhered to a synthetic material surface either before or after a thrombogenesis inhibitor is linked to the base coat.
The attachment of other molecules to the surfaces of artificial and natural materials, such as extruded or fibrous substances, is also of general interest. For example, materials treated with antibiotics, growth factors, or cytokines would have many uses in the fields of medicine and basic research.
Alternatively, the treatment of woven fabrics with molecules that impart color, or dyes, is useful to the textile industry. A dye is a compound that can be fixed on a substance in a more or less permanent state and that evokes the visual sensation of a specific color or hue.
In the textile industry it is often the dye, itself, which imparts the desired characteristic, i.e., color, to the fabric. While direct attachment of the dye may be useful, it is often desirable to impart other and/or additional characteristics to the fabric which are not directly provided by the application of known dyes. Such characteristics may include sheen, fluorescence, sparkle, hydrophobicity, an hydrophilicity.
Accordingly, it is an object of the present invention to provide a method of stably adhering molecules of interest to natural and synthetic materials such as extrudates, woven fabrics, and other materials.
Another object of the invention is to provide a treated material to which any number of molecules-of-interest can be stably adhered.
Yet another object is to provide biocompatible synthetic or natural materials useful for implantable and extracorporeal devices or for extracorporeal devices in contact with body tissues or fluids.
Still another object is to provide a molecule-of-interest stably adhered to a fixed support.
These and other objects of the invention will be apparent from the description, drawing, and claims that follow.

New England Deaconess Hospital Corporation


The track design for use with a tracked vehicle includes a cantilever cut made down into the outward side of each tread just outboard of the position where the inside of the track contacts the outboard edge of the tread of the outer wheel of each pair of track-supporting dual wheels. This cut significantly reduces lateral “roll-out” of the guide lugs from between the dual wheels when traversing uneven surfaces. When the outer edge of the track passes over sharply uneven terrain, this cut in the tread allows the outer edge of the track belt to lift away from the flat main surface under the wheels. Thus the interior surface of the track maintains contact with both tires of each pair of dual wheels by reducing twisting of the track belt that may cause the guide lugs to tip out of the mating surfaces formed between the dual-wheel pairs.

1. Field of the Invention
The invention pertains to the field of endless tracks used to propel track-laying vehicles. More particularly, the invention pertains to an improved track design for a track-laying vehicle.
2. Description of Related Art
Many track-laying vehicles are driven and supported by rubber tracks. As used herein, the term "rubber" relates to any elastic and primarily non-metallic materials such as rubber, elastomers, or combinations thereof used in the manufacture of endless tracks.
There is presently an acute need for a form of vehicle appropriate for both normal highway use and off-road use over snow-covered, uneven, or muddy terrain. There is significant need for such a vehicle following natural emergencies such as snowstorms, windstorms, and floods, and such vehicles are at present particularly needed in developing countries. Unfortunately, almost all available automotive vehicles require infrastructure, including paved highways and bridges, for practical operation, and the developing countries are decades away from having the necessary infrastructure for such conventional vehicles.
Rubber endless tracks are well known and provide supporting contact between a track-laying vehicle and the terrain over which the vehicle is to be moved. The tracks are carried by a plurality of rotating elements, such as wheels and sprockets, mounted on the track-laying vehicle. The tracks are maintained in circumferential contact with these rotating elements and are driven thereby, or, in the case of trailer-like non-driven vehicles, are supported for rotation thereon.
Most tracks are formed around a basic carcass or belt element having respective interior and exterior surfaces with a predetermined width dimension co-extensive with the track's overall track width. Terrain-contacting lugs are formed integral with the exterior surface of this basic belt element. Known rubber tracks include large lugs having a variety of well-known orientations. The external lugs are formed generally perpendicular to the track axis, at an angle to the track axis, or in a chevron or modified-chevron design.
One special variety of such tracks, disclosed in U.S. Pat. No. 6,135,220 by the inventor of the present invention and incorporated herein by reference, is designed to be driven by rubber-tired wheels and has been shown appropriate for the needs of multi-use tracked vehicles that are capable of being driven at highway speeds on paved highways in addition to use over uneven off-road terrain. These special tracks include interior lugs for maintaining the track in alignment as it travels over the circumferences of the rubber-tired wheels. The lugs are located in the center of the interior surface of the track for designs appropriate for fitting between the tires of dual-wheels or in two aligned rows near the outside edges of the track for receiving a single tire therebetween.
Other known rubber tracks, when mounted on the rotating wheels of vehicles, exert resistive forces that must be overcome to move the vehicle, specifically, resistive forces in addition to those forces created by the load being carried and/or generated by the terrain. These further resistive forces relate to the additional tensions required to stretch the heavy lugs of the tracks around the wheels over which they are mounted and to the additional friction generated between the tracks and the terrain. While the latter frictional resistive forces are a valuable attribute under wet or snowy conditions, they add undesirably to energy costs when driving the vehicle over flat, hard surfaces.
U.S. Pat. No. 6,241,327, also by the inventor of the present invention and incorporated herein by reference, discloses improvements to track designs that increase the efficiency of the off-road/highway-speed tracks specifically designed for multi-use tracked vehicles. In one improvement, a relatively thin cut is made in each lug portion of the tracks. In the preferred embodiments of the invention, the cut is made perpendicular to the track's central plane and parallel to the axes of the vehicle's rotating drive/support elements, and the cut is made throughout substantially the entire thickness dimension of each lug down to the exterior surface of the carcass belt. This improvement reduces the force required to stretch the heavy lugs of the track as the track changes direction when being moved over the circumferential surfaces of the rotating elements of the vehicle's track suspension system.
In a second improvement in U.S. Pat. No. 6,241,327, the track design includes a lug modification that is particularly applicable to those endless tracks used for suspension systems in which the track is supported and driven by rubber-tired wheels. This further modification selectively reduces the thickness of each lug by tapering each lug outboard of that central portion of the basic carcass/belt that is in direct contact with the rubber-tired supporting wheels. This modification reduces drag when driving over paved surfaces, while still providing desired additional traction when traversing wet or snow-covered terrain. This taper also facilitates pivot turning.
Prior to the present inventor's track design, load-carrying off-road vehicles had either very large wheels or very cumbersome tracks, which are heavy, slow-moving, and inappropriate for use on paved roads at normal highway speeds. While smaller all-terrain wheeled vehicles are commercially available, these do not carry adequate loads for normal multi-passenger or produce transport, and their drive wheels can easily become mired in heavy mud or snow. Therefore, track-laying vehicles of the type disclosed in the above-identified patents promise great utility for the future.
Although the track designs patented in U.S. Pat. No. 6,241,327 offer superior combinations of off-road, highway speed, and load carrying capabilities, the present inventor has found that under certain conditions the endless track may experience an undesirable "roll-out". That is, when only the outer edge of the track passes over a sharply uneven terrain, a severe twisting of the track belt can, in some instances, cause the guide lugs to tip out of the mating surfaces formed between the two supporting dual wheels, thereby dislodging the endless track laterally out of its normal alignment. Therefore, there is a need in the art for an improved endless track design with reduced roll-out.

Endless track for high speed multi-terrain vehicles


A switch panel including a switch unit is mounted on a dashboard of an automotive vehicle. The switch unit has switches for operating devices mounted on the vehicle and ornamental members disposed between the switches. The ornamental member is composed of a base portion and a portion extending from the base portion. Front surfaces of the extending portion and the base portion are covered with an ornamental light-reflecting layer. The front surface of the extending portion is positioned flush with a touch surface of the switch. The front surface of the base portion is sloped so that light incident thereon is reflected toward a direction not in parallel to a gap formed between the extending portion and the switch. The light reflected on the sloped surface is invisible while the front surface of the extending portion is clearly visible, enhancing ornamental design effects of the switch unit.

1. Field of the Invention
The present invention relates to a switch unit for operating electric or electronic devices mounted on an automotive vehicle.
2. Description of Related Art
A switch unit for operating devices mounted on an automotive vehicle, such as an air-conditioning device, an audio device and a car navigation system, is installed or provided in a compartment of a vehicle. An ornamental member having a light-reflecting surface is often used on a front surface of the switch unit to enhance an ornamental design. Such an ornamental member is installed at a desired position of the switch unit after it is manufactured separately from the switch unit. The ornamental member is often formed as a single body all covered with an ornamental light-reflecting layer.
The ornamental member is positioned close to a neighboring member such as a movable switch or a front panel. It is preferable to prevent light reflected on portions of the light-reflecting surface that do not contribute to ornamental design effects from reaching eyes of a driver or a passenger. However, it is difficult to intercept such reflected light because the light comes out through a gap between the ornamental member and the neighboring member. To prevent or suppress such reflected light, some techniques are known. For example: (1) making a rough surface underneath the light-reflecting layer, as disclosed in JP-A-2000-251561; (2) forming a layer for preventing light reflection on certain portion of the light-reflecting layer; and (3) preventing formation of the light-reflecting layer on portions where the light-reflecting layer is not desired to be formed.
However, the technique (1) is not sufficiently effective because the rough surface formed underneath the light-reflecting layer is smoothened by forming the light-reflecting layer thereon. The technique (2) requires an additional process for forming the preventing layer. In addition, portions on which the preventing layer is not to be formed have to be masked. Similarly, in technique (3), it is necessary to mask the portions on which formation of the light-reflecting layer is not desired, requiring an additional process.

Operating switch unit for use in automotive vehicle


An illuminating optical apparatus comprises a stable resonator type laser equipped with a wavelength selecting element and a device for vibrating the beam one-dimensionally in a direction crossing the longer direction of the beam cross section at at least one of the entrance side and exit side of a fly's eye lens or optical integrator.

1. Field of the Invention
The present invention relates to an illuminating optical apparatus utilizing a coherent light beam such as an excimer laser beam, adapted for use in an exposure apparatus for semiconductor device manufacture or the like.
2. Related Background Art
As the light source for the exposure apparatus employed in the manufacture of integrated circuits, there have principally been employed ultra-high pressure mercury lamps. However, the recent remarkable progress in the level of integration of such integrated circuits is requiring an ever increasing precision on the line width. For this reason ultra-high pressure mercury lamps are starting to be replaced by high power lasers of shorter wavelength such as excimer lasers, as the light source.
The excimer lasers can be classified into two categories, one of which is called a stable resonator type. In this type, as shown in FIG. 1, a resonator is composed of a discharge lamp 100 for causing induced emission, with two resonator mirrors 102a, 102b positioned at opposite ends. The light reciprocates between the mirrors whereby the amplitude of the induced emission is intensified to emit a laser beam LB.sub.0. The laser beam emitted from such laser is characterized by low coherence in space and time. The low coherence in time signifies a wide half value width of the spectrum (.DELTA..lambda..congruent.0.4 nm). For use in the exposure apparatus for semiconductor device manufacture, such light source requires correction of color aberration in the projection lens, and it is difficult to provide a practical lens in such short wavelength range.
The other light source is called an injection lock type, which is divided into an oscillator and an amplifier as shown in FIG. 2. The oscillator is provided with oscillator mirrors 102a, 102b as in the above-mentioned stable resonator type. However, in the injection lock type, the oscillator is further provided with a wavelength selecting element 106 such as an etalon and a diffraction grating, and with apertures 104a, 104b at opposite ends of the discharge tube 100 for the purpose of intercepting the laser beam in a predetermined area, whereby the emitted laser beam has a narrower half-value width of the spectrum (.DELTA..lambda..congruent.0.001 nm) or improved monochromaticity. In addition the emitted laser beam is reflected by mirrors 108 and is amplified by unstable resonator mirrors 112a, 112b with mutually opposed convex and concave faces, positioned at opposite ends of a second discharge tube 110. One of the features of the laser beam from such laser is the improved monochromaticity with high coherence in time, whereby the correction of color aberration can be dispensed with in the projection lens.
For this reason the projection lens can be manufactured with a single material (quartz), so that the designing and manufacture are easy. However another feature of the injection locking laser is an extremely high coherence in space due to the amplification by the unstable resonator, and the use of such laser will result in marked interference fringes in the exposed area.
For avoiding such inconvenience, there has been developed a new type of laser as shown in FIG. 3, which is composed of the aforementioned stable resonator laser and a wavelength selecting element 114 for reducing the wavelength band width, such as an etalon, a prism or a diffraction grating, whereby the emitted laser beam has a narrower width of spectrum (.DELTA..lambda..congruent.0.003 nm). The laser beam from such laser has an improved coherence in time due to the presence of the wavelength selecting element 114, and a lower coherence in space in comparison with that from the injection locking type.
U.S. Pat. No. 4,619,508 discloses a method for reducing speckles resulting from the interference of a laser beam, by providing a rotating mirror or the like in the optical path of the illuminating system for causing two-dimensional scanning motion of the beam, thereby reducing the coherence in space.
Also U.S. patent application Ser. No. 135,378 filed Dec. 21, 1987 (now U.S. Pat. No. 4,851,978 issued Jul. 25, 1989) proposes effectively eliminating the speckles generated with the laser beam of high coherence in time and space emitted from the injection locking laser by means of beam vibration, i.e., two-dimensional movement of the beam in synchronization with the emitted pulses of the laser and in correspondence with the arrangement of elements of a lens member, such as a fly's eye lens, provided for obtaining uniform intensity distribution of the beam.
However, in such methods, it is difficult to obtain an appropriate amount of exposure within a short period, or the throughput has to be significantly reduced in order to secure the appropriate amount of exposure.
A high-power laser beam entering a fly's eye lens generates secondary light sources of an extremely high luminocity, which may cause destruction of optical components if such secondary light sources are focused thereon. Also weak reflected light, generated for example on a lens surface, if focused in the vicinity of the reticle, will be refocused on the wafer, thus generating a ghost image.
The first of the above-mentioned drawbacks of the fly's eye lens can be solved, as disclosed in the U.S. patent application Ser. No. 237,847 filed Aug. 26, 1988 (now U.S. Pat. No. 4,939,630 issued Jul. 3, 1990), by focusing the secondary light sources in a space outside the optical components. Also the latter of the drawbacks can be solved by a serial arrangement of two optical integrators, as disclosed in the U.S. Pat. No. 4,497,015.
However such double optical integrators give rise to the formation of speckles due to interference fringes. More specifically, the light fluxes emerging from the secondary light sources formed by the first optical integrator do not mutually interfere, but those from tertiary light sources formed by the second optical integrator interfere mutually for the following reason. The diameter of beams passing through the element lenses of the first integrator is expanded to about 10 times upon reaching the second integrator, so that the non-interfering distance of two light beams is also expanded to about 10 times. Thus the non-interfering distance becomes larger than the pitch of the element lenses of the second optical integrator, so that the tertiary light sources formed on the exit portions of the element lenses can mutually interfere.


In a semiconductor integrated circuit for taking in an external power source voltage from outside the semiconductor chip, the external power source voltage is dropped by a voltage dropping unit installed inside the semiconductor chip and the external power source voltage in the semiconductor integrated circuit, as dropped is supplied as an internal power source voltage to the semiconductor chip and used as the internal power source voltage, a plurality of voltage dropping units are installed for each of a plurality of semiconductor circuit block installed inside the semiconductor chip, and the voltage fluctuation of an internal power source is effectively suppressed in the event that a circuit consuming a very high current is operated.

1. Field of the Invention
The present invention relates to a semiconductor integrated circuit, and more particularly, relates to a semiconductor integrated circuit for dropping an external power source voltage to thereby obtain an internal power source voltage
2. Description of the Relevant Art
In general, it is preferable that miniaturization of semiconductor elements continue so that the integration level of semiconductor integrated circuits can be enhanced. However, the further miniaturization of semiconductor elements leads to such disadvantages as a lowering of the pressure resistance thereof and the possibility that the element will be adversely influenced by hot electrons.
As an effective countermeasure against these inconveniences, is the lowering of the power source voltage to be supplied to the semiconductor element so as to minimize the electric field strength of the respective portions of the element. For example, the destruction by aging of an oxidated film can be prevented by lowering the electric field strength of the oxidated film. Further, by lowering the channel electric field strength, the generation of hot electrons can be suppressed to thereby reduce the amount of hot electrons injected into the oxidated film, i.e., the hot electron instability (concretely, the variation of threshold value V.sub.th and a poor conductance) can be prevented.
Many of the problems arising in miniaturized elements can be solved if the power source voltage is thus lowered, but it is not preferable for the preparation of an exclusive-use external power source because the system becomes complex and dedicated power source wires are required. Therefore, the method of dropping the external power source voltage inside a semiconductor integrated circuit to thus form a low voltage internal power source is generally adopted. FIG. 1 and FIG. 2 show the structure of a conventional semiconductor integrated circuit for dropping the external power source voltage inside the semiconductor integrated circuit in order to produce a low voltage internal power source. In FIG. 1, VccPAD is a power source terminal installed at a semiconductor chip, to which the external power source is to be applied, "A" is a voltage drop circuit, and C11 through C1n represent a plurality ("n" units) of semiconductor circuits The power source terminal VccPAD is installed, usually as one body, on the semiconductor chip 2, and the semiconductor circuits C11 through C1n are two-dimensionally arranged in the plane of the semiconductor chip 2. The voltage drop circuit "A" forms an internal power source voltage Vint, which drops the external power source voltage applied to the power source terminal VccPAD, to a given voltage. This external voltage is a common power source voltage which is also applied to the other semiconductor integrated circuits and is, for example, +5 V. The voltage is dropped to a given level by utilizing, for example, the channel resistance of a MOS transistor.
The given voltage referred to herein means the voltage necessary for the actuation of a miniaturized semiconductor element (for example, a MOS transistor) forming a structure of a plurality of internal semiconductor circuits C11 through C1n, and moreover, which effectively avoids a pressure resistance and hot electrons.
FIG. 3 shows an example of semiconductor circuits C11 through C1n given in FIG. 1, wherein the semiconductor integrated circuit is a dynamic RAM. In this FIGURE, C.sub.11 is a mode control circuit, C.sub.12 a refresh address counter, C.sub.13 an address buffer, C.sub.14 a pre-decoder, C.sub.15 a basic bias generating circuit, C.sub.16 a sense amplifier driver, C.sub.17 a first clock generating circuit, C.sub.18 a gate circuit, C.sub.19 a second clock generating circuit, C.sub.20 a write clock generating circuit, C.sub.21 a column decoder, C.sub.22 a low decoder, C.sub.23 a date input buffer and C.sub.24 a data output buffer, and the internal power source voltage, which has been dropped by the voltage drop circuit "A," can be supplied to each of these semiconductor circuits C11 through C24. FIG. 4A is a circuit diagram showing the structure example of the address buffer of FIG. 3, whereas FIG. 4B is a circuit diagram showing the structure example of the pre-decoder of FIG. 3.
In this type of conventional semiconductor integrated circuit, however, because a plurality of internal semiconductor integrated circuits (C11 through C1n in FIG. 1, and C.sub.11 through C.sub.1n in FIG. 3) use a single internal power source voltage Vint in common there is a danger that the potential of Vint will instantaneously drop, and thus the other semiconductor circuits may malfunction because of this; for example, when a semiconductor circuit consuming a very large current is actuated outside of these internal semiconductor circuits (C11 through C1n in FIG. 1 and C.sub.11 through C.sub.1n in FIG. 3).
Therefore, a technique is employed such as the installation of a circuit to detect the voltage drop of the internal power source voltage Vint, and supplying a comparatively large current when the voltage drop has been detected, thus suppress the fluctuations of internal power source voltage. In this method, however, a delay in the response, to a certain degree, was unavoidable until the current was supplied after the actual voltage drop, and as a result, the conventional circuit could not properly or effectively suppress the instantaneous voltage drop of the internal power source voltage Vint.