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Biomedical subjects

M Kamiyama

Publications and source records attributed to M Kamiyama.

At least 55 records · Page 3Linked to original sources
PubMed1989

In vivo binding of circulating immune complexes by C3b receptors (CR1) of transfused erythrocytes.

The effects of packed erythrocyte transfusion with high CR1 activity on circulating immune complex concentrations were studied in 14 transfusion experiments involving 12 patients with immune complex related diseases. Before erythrocyte transfusion circulating immune complex concentrations ranged from 8 to 128 micrograms/ml. After transfusion (2-3 units) immune complex concentrations decreased depending on the levels of CH50 titres in the recipients. In 11 experiments, in which the patients' CH50 titres ranged from 21 to 44, immune complex concentrations decreased by 75-100% within five days. The CH50 titres were also decreased after erythrocyte transfusion but subsequently increased to initial ranges within 6-35 days. In three patients with low CH50 titres (1.0-10.0) decreases in immune complexes were not observed. Direct Coombs' tests for IgG and C3 were performed before and after erythrocyte transfusion to determine potential in vivo binding of circulating immune complexes. Thus in eight of 14 experiments, in which erythrocytes carried no IgG before packed erythrocyte transfusion, seven became Coombs' positive for IgG after the transfusion. In seven of 14 experiments, in which erythrocytes were negative for complement before transfusion, five became positive afterwards. Moreover, in 12 instances slight increases of CR1 activity of patients' erythrocytes were observed within eight days, which improved further within 35 days after erythrocyte transfusion. These studies suggest that transfusion of erythrocytes with high CR1 activity results in the removal of circulating immune complexes and that this process is dependent on complement consumption. These experiments support the hypothesis that erythrocyte-CR1 has a functional role in the removal of circulating immune complexes and may thereby inhibit the deposition of immune complexes within body tissue constituents.

Antigen-Antibody Complex↗
PubMed1988

Steroid therapy in IgA nephropathy: a retrospective study in heavy proteinuric cases.

29 patients with IgA nephropathy whose proteinuria persisted at a level of 2.0 g/day or more and who received prednisolone treatment for 1-3 years were retrospectively evaluated on their clinical courses. 13 of 14 patients with renal dysfunction of less than 70 ml/min in initial creatinine clearance (Ccr) values subsequently entered a progressive course during a follow-up period of 47 months, leading to end-stage renal failure in 8 cases. On the other hand, only 1 of the other 15 patients with preserved renal function of 70 ml/min or more ended up with end-stage renal failure during a follow-up period of 74 months, although 7 underwent a progressive course. Three patients in the latter group experienced a prominent reduction in proteinuria to less than 1.0 g/day and maintained renal function. Meanwhile, the steroid group of moderate proteinuric patients with a creatinine clearance greater than 70 ml/min had a benign course, while the nonsteroid group had an unfavorable one. These results suggest that steroid therapy in IgA nephropathy may be able to stabilize a progressive course, especially in the early stage of the disease, although, because they come from an uncontrolled study, a definite conclusion cannot be drawn.

Adolescent↗
PubMed1988

Glomerulonephropathy with amyloid-stain-negative microfibrillar glomerular deposits.

A 44-year-old man demonstrated proteinuria, microhematuria and renal dysfunction during the course of hyperthyroidism. Neither cryoglobulinemia nor paraproteinemia including light chains was found. No systemic signs suggestive of amyloidosis appeared. Histological findings showed a diffuse mesangial matrix increase with slight mesangial proliferation and diffuse granular depositions of IgG, IgA, C3, C4, Clq, kappa and lambda light chains. Ultrastructurally, microfibrils of about 20 nm in width were seen to be deposited diffusely in mesangial areas and in glomerular basement membranes. Congo red and thioflavin T staining were negative. These findings support the possible existence of a specific glomerular disease different from amyloidosis.

Adult↗
PubMed1987

Antibodies to a surface membrane marker from human mammary carcinoma cell line.

A tumor surface antigen (BTA-BT20-68K) was isolated from a human mammary carcinoma cell line (BT-20). The antigen (Mr 68,000) induced the formation of high titer antibodies which recognized BTA-BT20-68K as a cell surface marker by the immune adherence hemagglutination test and recognized the soluble antigen by solid phase radioimmunoassay. The antibodies which failed to recognize human beta-2-microglobulin, alpha-fetoprotein, and carcinoembryonic antigen were cytotoxic to the parent BT-20 tumor cells at high serum dilutions. The antibodies recognized a similar tumor surface marker isolated directly from human breast adenocarcinomas, but failed to recognize human lymphocyte antigens isolated from BT-20 cells or bound to human lymphocytes bearing human lymphocyte antigen markers in common with those of BT-20 cells. Added to BT-20 tumor cells in culture and in the absence of complement, antibody-dose-related inhibition of tumor cell growth was documented. In the presence of complement, the antibodies were highly cytotoxic to the parent cells. These results demonstrate the presence of a unique tumor surface marker with chemical and immunological properties in common with that isolated directly from human breast adenocarcinomas.

Adenocarcinoma↗
PubMed1986

Acetylation and phosphorylation of histones and nonhistone chromosomal proteins in neuronal and glial nuclei purified from cerebral hemispheres of developing rat brain.

The processes of acetylation and phosphorylation of histones and nonhistone proteins (NHPs) in neuronal and glial nuclei purified from cerebral hemispheres of rats at 1, 10, and 30 days of age were investigated. Purified neuronal and glial nuclei were incubated in the presence of [3H]acetyl-CoA and of [gamma-32P]ATP. Histones and NHPs were extracted and fractionated by gel electrophoresis. Densitometric and radioactive patterns were obtained. The results showed an increase of acetylation and phosphorylation from 1 to 10 and 30 days of age in both neuronal and glial nuclei in almost all histone and NHP fractions. Among the histones, the H3 fraction was always more labeled than the other fractions and showed the most remarkable differences during postnatal development. In the NHP fractions, the increase in acetylation from 1 to 10 and 30 days of age was more evident in the low-molecular-weight region of neuronal nuclei than in the corresponding fraction of glial nuclei. The appearance of highly phosphorylated proteins (70,000-90,000 daltons)--absent at 1 day, appearing at 10 days, and more evident at 30 days of age--was observed in both neuronal and glial nuclei.

Acetylation↗
PubMed1986

Relationships between C3b receptor (CR1) activity of erythrocytes and positive Coombs' tests.

Although positive direct Coombs' tests occur in most patients with active systemic lupus erythematosus (SLE), haemolytic anaemic associated with antibody to erythrocytes (E) occurs in less than 10%. Our studies show an association between positive direct Coombs' tests and both the presence of circulating immune complexes and diminished activity of the C3b receptor (CR1) of E. Data presented in this report suggest that in vivo binding of immune complexes and complement by the CR1 of E results in positive direct Coombs' tests in the absence of antibody to E. These observations explain the low frequency of haemolytic anaemia compared with the high frequency of direct positive Coombs' tests in patients with SLE.

Antibodies↗
PubMed1985

Methylation of chromosomal proteins in neuronal and glial nuclei purified from cerebral hemispheres of rat during postnatal development.

The process of methylation of chromosomal proteins [histones and nonhistone proteins (NHP)] in neuronal and glial cell nuclei obtained from cerebral hemispheres of rats at 1, 10, and 30 days of age was investigated. Purified neuronal and glial nuclei were incubated in the presence of S-adenosyl[methyl-3H]methionine. Histone and NHPs were extracted and fractionated by polyacrylamide gel electrophoresis. The results obtained indicate remarkable differences in the process of methylation of histones and NHPs between neuronal and glial nuclei, especially during the first period of postnatal development. In both nuclear populations the histone fraction H3 was labeled to a greater degree than the other fractions and showed the major changes during postnatal development. The densitometric and radioactive patterns of NHPs show considerable changes in the two nuclear populations at the various ages examined. The main difference between neuronal and glial nuclei consists in the intense methylation of proteins with a molecular weight of approximately 100,000, which are present in neuronal nuclei and virtually absent in glial ones. The results obtained may be correlated with the different chromatin structures of neuronal and glial nuclei and with the patterns of maturation and differentiation of neuronal and glial cells during postnatal development.

Age Factors↗
PubMed1983

Post-translational changes of chromosomal proteins in rat cerebellum during postnatal development.

Acetylation, phosphorylation and methylation of nuclear proteins in rat cerebellum at 10 and 30 days of age were investigated in vitro. Isolated nuclei were incubated in the presence of [1-14C]acetyl CoA, S-adenosyl [methyl-3H]methionine and [gamma-32P]ATP and then separated into histones and non histone proteins (NHP), which were further fractionated by polyacrylamide gel electrophoresis. The results obtained indicate that acetylation, phosphorylation and methylation of both basic and acidic proteins decrease from 10 to 30 days of age. Electrophoretic analysis of histones shows that the decrease mainly concerns H1, H3, and H2b fractions. The H3 fraction is always more labeled than the other fractions and shows the major changes during postnatal development. Phosphorylation of H2a and H4 fractions increases from 10 to 30 days of age, whereas acetylation and methylation of these fractions do not show significant changes from 10 to 30 days. The densitometric and radioactive patterns of NHP show considerable changes between 10 and 30 days, especially in the high molecular weight region. The incorporation of 14C-acetyl and 3H-methyl groups and of 32P phosphate appears to be generalized throughout the molecular weight range and decreases from 10 to 30 days of age. The methylation of an as yet unidentified protein with a molecular weight of approximately 110,000 daltons occurred at both ages.

Acetylation↗
PubMed1983

Posttranslational modifications of nuclear proteins in rat cerebral hemispheres during postnatal development.

The processes of acetylation, phosphorylation, and methylation of nuclear proteins in cerebral hemispheres of 10- and 30-day-old rats were investigated. The experiments were carried out in vitro by measuring the incorporation of labeled precursors into histones and nonhistone chromosomal proteins (NHP) extracted from nuclei and separated by polyacrylamide gel electrophoresis. The results obtained indicate that there are age-specific differences in the processes of phosphorylation and methylation of chromosomal proteins, whereas the acetylation process did not change significantly between 10 and 30 days of age. Electrophoretic analysis of histones indicated that the histone H3 was labeled to a greater degree than the other fractions and showed major changes in the processes of phosphorylation and methylation during postnatal development. The electrophoretic analysis of NHP showed considerable changes between 10 and 30 days of age. Certain components of NHP became increasingly evident as the brain developed. The methylation of an as yet unidentified protein with a molecular weight of approximately 118,000 daltons occurred at both ages.

Acetylation↗
PubMed1983

Studies on immune adherence (C3b) receptor activity of human erythrocytes: relationship between receptor activity and membrane osmotic fragility.

Although human erythrocytes (E) possess C3b receptors (C3b-R), their in vivo functions are unknown. We had observed that E from patients with immune complex diseases had defective or impaired C3b-R activity when circulating immune complexes (CIC) could be demonstrated. This phenomenon has been investigated in relation to membrane osmotic fragility of such E by a coil planet centrifugation (CPC) system. Osmotic fragility was defined by the hemolysis starting point (HSP), peak point (HPP) and end point (HEP) using NaCl osmotic gradient (150-30 mOsM) coiled tubes. It was observed that E with low C3b-R activity showed high osmotic fragility. Hemolysis of E with low C3b-R activity started at 104 +/- 8 mOsM (n = 133) compared to 97 +/- 3 mOsM (n = 18) of patients' E with normal C3b-R activity and 96 +/- 5 mOsM of E from normal healthy donors (n = 128). Furthermore, we observed that HSP shifted towards lower osmolarity with clinical and immunological improvement of disease activity after treatment with corticosteroids. When osmotic gradients were lower to 120-50 mOsM, 52 out of 116 E samples with low C3b-R activity separated into 2 E populations. In contrast, none of 18 E samples with normal C3b-R activity separated into 2 E populations. However, we observed broadened fragility patterns in these 18 E samples. Serial studies of C3b-R activity, osmotic fragility and the presence of CIC were performed in 7 patients. Improvement of disease activity was associated with increased C3b-R activity, decreased osmotic fragility and the disappearance of CIC.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenal Cortex Hormones↗
PubMed1982

Studies on immune adherence (C3b) receptor activity of human erythrocytes: relationship between receptor activity and presence of immune complexes in serum.

Human erythrocytes (E) have surface receptors for the third component of complement (C3b-IA receptors) which mediate immune adherence haemagglutination (IAHA). We have observed that E from patients with systemic lupus erythematosus had imparied or defective C3b receptor (C3b-R) activity when circulating immune complexes (CIC) were found in serum. This phenomenon has been investigated by a newly developed method involving competitive inhibition of IAHA in patients with immune complex diseases. IAHA involving sheep E coated with antibody and complement (EAC), and indicator human E was inhibited by lysates of E with normal C3b-R activity from healthy donors and a monkey. In contrast, the lysates of E from 95% of patients bearing CIC did not inhibit IAHA, which indicated such E had defective or impaired C3b-R activity. This phenomenon was supported by control studies in which IAHA was not inhibited by lysates of E with absent, inactivated or occupied C3b-R. In those patients, in whom CIC disappeared during immunosuppressive therapy, C3b-R activity slowly returned to normal levels. Moreover, it was observed that C3b-R activity of patients' E decreased with the reappearance of CIC during exacerbations of disease. These observations suggest that CIC are carried in vivo by the C3b-R of E as well as those of the mononuclear phagocyte system, and that the E C3b-R may also contribute to the clearance of CIC.

Animals↗