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Biomedical subjects

T Furuyama

Publications and source records attributed to T Furuyama.

At least 73 records · Page 4Linked to original sources

Distribution of fibronectin and other connective tissue components in human placenta.

Human placenta specimens obtained at term were investigated for distribution of fibronectin, collagens and glycosaminoglycans. When examined by the immunofluorescence staining technique with anti-plasma fibronectin antiserum, fibronectin was shown to be present around the fetal blood vessels and in the stroma of placental villi. The distribution of type IV collagen also was examined with specific antiserum. It was found that its distribution was similar to that of fibronectin. Conventional alcian blue staining indicated that the placental villi contained only small amounts of glycosaminoglycans. These data suggest that fibronectin and type IV collagen play important roles in tissue organization of the placental villi.

Chorionic Villi↗

Modified anti-C3 immune complex assay which avoids interference by anti-F(ab')2 antibodies.

The present authors and Olds et al. reported that the anti-F(ab')2 antibodies (Abs) in serum interfere with the solid phase (SP) anti-C3 immune complex assay. The anti-F(ab')2 Abs in human sera bind solid phase F(ab')2 anti-C3 of rabbit or goat, and were measured erroneously as C3 bearing circulating immune complexes (CIC). Gel filtration analysis of SP anti-C3 assay revealed that C3 bearing CIC is detected only in heavy fractions and 7S CIC-like activity is not CIC but anti-F(ab')2 activity. As the molecular weight of such CIC is heavy enough to be precipitated by 5% polyethylene glycol (PEG) and IgG anti-F(ab')2 Abs and free C3 are not included in 5% PEG precipitates, 5% PEG precipitates of the test sera were used for SP anti-C3 (Modified SP anti-C3). CIC measured by modified SP anti-C3 were positive in 14/16 at active stage of SLE and positive only in 2/16 at inactive stage. CIC by this test were also correlated well to serum complement activity, and were thought to be clinically reliable and useful.

Antibodies↗

Circulating immune complex-like materials which bind to heat inactivated C1q interfere with the C1q solid phase assay for immune complexes.

C1q solid phase assay (C1q SP) was devised based on the fact that immune complexes (IC) and aggregated human globulin (AHG) bind to C1q. Neither IC nor AHG was found to bind to heat inactivated C1q. On the other hand, circulating immune complex (CIC)-like materials in patients' sera were able to bind to heat inactivated C1q, indicating that these CIC-like materials are not true CIC. Gel filtration analysis showed that molecular size of such CIC-like materials was almost the same as monomeric IgG, while true CIC were in heavy fractions. True CIC did not bind to heat inactivated C1q but bind only to native C1q. The CIC-like activity is not due to rheumatoid factors. About 2/3 of CIC positive sera by C1q-SP are not really CIC positive but are due to interference by the CIC-like materials.

Animals↗

A new and specific enzyme-linked immunosorbent assay for the detection of C3 nephritic factor.

C3 nephritic factor (C3 NeF) was measured by assessing its capacity to form complex with C3 and B using an enzyme-linked immunosorbent assay (ELISA). Incubation of C3 NeF with normal human serum in the presence of MgEGTA resulted in a dose-dependent increase of C3-B-IgG complex. No complex was formed in EDTA. The C3 NeF titer estimated in this way was in good accordance with those reported previously by other indirect methods.

Complement C3↗

Changes in distribution of connective tissue components of human placentae with maturation.

The distributional changes of type IV collagen and laminin with normal maturation of human placentae were examined in relation to those of fibronectin by the histochemical methods including immunofluorescence staining. In the early chorionic villi, these components were detected along the trophoblastic basement membrane, around the fetal blood vessels, and in the villous stroma. Laminin was detected also in the pericellular matrices of nonvillous cytotrophoblasts where type IV collagen was rarely detected. In the late and term placentae, laminin and type IV collagen were detected along the trophoblastic basement membrane, while this structure was virtually not stained for fibronectin. These observations suggest that type IV collagen and laminin are the constituents of the trophoblastic basement membrane throughout the maturation period of the placentae, while fibronectin is a transient constituent.

Chorionic Villi↗

The effect of protamine on serum complement activity in aminonucleoside nephropathy.

Combined administration of protamine sulfate (Ps) and aminonucleoside (AN) to rats causes severe nephrotic syndrome and, histologically, focal glomerular sclerosis. These changes are more distinct than those produced by AN alone. While the exact mechanism of Ps acting on AN nephropathy is not known, marked hypocomplementemia was observed regularly after the Ps + AN injection, suggesting that complement is activated and consumed in the kidney. It is suggested that complement may play an important role in AN + Ps nephropathy.

Animals↗

The effect of protamine on proteinuria and glomerular sclerosis in aminonucleoside nephropathy.

An administration of protamine sulfate combined with aminonucleoside of puromycin (AN) could produce in rats severe nephrotic syndrome and histological changes similar to focal glomerular sclerosis more distinctly than AN alone. This may be attributed to the action of protamine which seemed to enhance the effect of AN, causing polyanion loss at the glomerular basement membrane.

Animals↗

Relationship between complement-fixing (hemolytic) antibodies to single-stranded and double-stranded DNA and the prognosis in systemic lupus erythematosus.

Hemolytic (complement-fixing) antibodies to single-stranded (ss) or double-stranded (ds) DNA, measured by recently developed PHL assay, occurred closely correlated with renal activity in patients with systemic lupus (SLE). Approximately one third of the patients with renal disease had hemolytic antibodies to ss-DNA but never to ds-DNA. Hemolytic antibodies were scarcely detectable in patients with mild course. Serial studies also revealed that the estimation of the hemolytic antibodies to ds- and/or ss-DNA was particularly valuable in predicting the future course of the SLE. The emergence of hemolytic antibodies to DNA may be an ominous sign suggestive of grave prognosis in SLE.

Adolescent↗

Nephritic factor (NeF) of alternate pathway (NeFA) and of classical pathway (NeFc).

NeFA and NeFc were studied in various cases (115 cases). 5 cases were followed up for a long time. NeFA assay was done by the "microtest plate method". We detected the NeF activity for the first time in the cases of Sjögren syndrome (SjS) and SjS+SLE+Hashimoto's disease (Hashimoto). In some cases NeF activity disappeared after therapy, and in one case NeFA and NeFc were positive at first, but then only NeFA activity became negative following the adequate therapy. As to the antibody nature of NeF, the possibility was suggested that NeFA might be anti C3b autoantibody and NeFc might be anti C4b and/or C4b2a auto-antibody.

Complement Activation↗

'Nephritic factor' may be an autoantibody to C3b or C4b.

We attempted to clarify the character of 'Nephritic Factor' in the alternative (NeFA) and classical pathways (NeFC) of the complement, using an agglutinating and a hemolytic activity assay. The results suggested a possibility that NeFA and NeFC were different in their ability but might appear at the same time in some cases, and that NeFA was anti-C3b autoantibody and NeFC anti-C4b autoantibody.

Autoantibodies↗