Human amyloid P-component was isolated from plasma by affinity chromatography utilizing antiserum to tissue P-component coupled to Sepharose 4B. Characterization and comparison of the isolated P-component proteins from tissue and plasma demonstrated immunologic identity and identical RF values of polyacrylamide disk gel electrophoresis. Amino acid analyses of P-components from two individual plasmas were comparable, but some variations from tissue P-component were noted. Attempts to perform amino acid sequencing on the plasma protein were unsuccessful. Electron microscopic studies revealed that the plasma P-component had a pentagonal ultrastructure identical to the tissue P-component. These studies compared similarities of tissue and plasma P-components and revealed the unique pentagonal ultrastructure of the plasma protein.

Alpha-Globulins↗

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Ultrastructural studies of renal peritubular amyloid experimentally induced in guinea pigs. II. Tubular epithelial cells.

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Amyloid↗

PubMedDate not supplied

Proteoglycans in amyloidogenesis.

The potentially important role of proteoglycans and glycosaminoglycans in the modern concept of general amyloidogenesis has been discussed.

Alzheimer Disease↗

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Alpha 1-antichymotrypsin is associated solely with amyloid deposits containing the beta-protein. Amyloid and cell localization of alpha 1-antichymotrypsin.

Our recent studies demonstrated that alpha 1-antichymotrypsin (ACT), a serine protease inhibitor, was associated with the beta-protein in the brain amyloid deposits of Alzheimer's disease, aged human controls and aged monkeys, suggesting a role for the inhibitor in the amyloid deposition. In the present study we used immunohistochemistry to test for the presence of ACT in the amyloid deposits which contain, as their major component, a protein different from the beta-protein. ACT was not found in the amyloid deposits in primary or secondary amyloidosis, familial and amyloidotic polyneuropathy or Creutzfeldt-Jakob disease (non-beta-protein amyloidoses), but was found (together with beta-protein) in Alzheimer's disease, Down's syndrome, normal aging, and hereditary cerebral hemorrhage with amyloidosis of Dutch origin. These results suggest a specific association of ACT with beta-protein amyloid. We next examined the distribution of the inhibitor in normal human brain and in various human neuropathological states in order to identify cells that express this protein during brain degeneration. In addition to its association with amyloid, ACT immunoreactivity was also located in astrocytes near areas of neuronal or tissue loss, in a few neurons and pericytes and in the epithelium of the choroid plexus.

Alzheimer Disease↗

PubMedDate not supplied

Expression of Thrombomodulin in the epithelium of the urinary bladder: a possible source of urinary thrombomodulin.

Thrombomodulin (TM) is an endothelial thrombin receptor which acts as a natural anticoagulant through inactivation of the procoagulant activity of thromin. In the present study, we demonstrated that TM is expressed on the urinary bladder epithelium. The cell line BOY established from human transitional cell carcinoma of the urinary bladder also expressed the TM message (3.7kb). These cells express an 85 kDa TM protein which is identical in size to that of MEG-01, a human megakaryoblastic cell line, reported previously. We also ascertained the expression and localization of TM in the human urinary bladder by immunohistochemical staining. TM was localized in the membranes of the transitional epithelium and the cytoplasmic region of umbrella cells. The expression of TM in the transitional epithelium increased with worsening pathological status of cystitis. Based on these results, we concluded that TM is expressed in the urinary bladder. Further, soluble TM in urine may be partially derived from the urinary bladder. At present, the physiological significance of TM expression in the urinary bladder remains to be elucidated.

Animals↗

PubMedDate not supplied

Infrequent activation of mitogen-activated protein kinase in human colon cancers.

BACKGROUND/AIMS: Mitogen-activated protein kinase (MAPK) is a downstream factor of the Ras-Raf-MAPK cascade and it is now considered to be a key molecule in signaling processes stimulated by growth factors and differentiation inducers. METHODOLOGY: We examined MAPK activity in 21 advanced colon cancers to investigate whether the MAPK cascade might play a role in the progression of colon cancers. RESULTS: MAPK activation (3.9-10.1-fold) was observed in 4 of 21 cases (18%), but 3 cases (75%, 3 of 4 cases) showed MAPK activation without ras mutation, thus suggesting that MAPK activation did not correlate with the presence of Ki-ras mutations in these cases. Other kinds of oncogene activation would be involved to MAPK activation in human colon cancers. In other cases MAPK activation was not detected or partly down-regulated. CONCLUSIONS: These findings suggest that positive and negative regulation of MAPK activity are associated with loss of normal growth control and may be involved in carcinogenesis of colon cancers.

Cell Transformation, Neoplastic↗

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The antitumor effects of IFN- beta against human renal cell carcinoma in athymic nude mice.

IFN-beta was more active than recombinant interferon-alpha (rIFN-alpha) and interferon-gamma (rIFN-gamma) in a human renal cell carcinoma transplanted in nude mice. In 3 out of 5 mice, the tumor completely disappeared and viable tumor cells were not observed at a daily dose of 5 x 10(5) U/mouse. Combination with anti-asialo GM1 antibody did not influence the tumor growth inhibition by IFN-beta. Mononuclear cells around damaged cancer cells were found not to be macrophages. Although the role of mononuclear cells remained unknown, the antitumor activity of IFN-beta seemed to depend on its direct cellular action. IFN-beta may be a useful agent in some renal cell carcinomas.

Animals↗