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Biomedical subjects

Y Nakamoto

Publications and source records attributed to Y Nakamoto.

At least 145 records · Page 8Linked to original sources
PubMed1986

Serum Erythropoietin levels and inhibitors of erythropoiesis in patients with chronic renal failure.

The role of various factors in erythropoiesis was studied in 13 predialysis patients and 41 hemodialysis patients. Serum erythropoietin (ESF) was measured by the fetal mouse liver cell bioassay in vitro. The effect of uremic sera on heme synthesis and erythroid progenitor cell (CFU-E) formation was examined using normal human bone marrow cultures. Serum ESF levels in both predialysis (99.9 +/- 45.0 mU/ml) and dialysis (141.2 +/- 109.7 mU/ml) patients were significantly higher than those in normal controls (42.0 +/- 25.8 mU/ml), although the titers were not sufficiently increased to correct the anemia. Serum ESF concentrations did not correlate with hemoglobin level or inhibition of both heme synthesis and CFU-E formation. Bone marrow CFU-Es in uremic patients were normal in the number, the responsiveness to ESF and the percentage in S-phase. Significant decrease in heme synthesis was observed in dialysis patients. The degree of inhibition of CFU-E formation showed a relationship to hemoglobin levels in uremic patients. By the CFU-E formation assay, the difference in inhibitory effects of the sera obtained from dialysis patients immediately before and after a hemodialysis was significant only under a low ESF concentration (0.125 U/ml) but not under a high concentration (1.0 U/ml). In conclusion, inhibition of heme synthesis and CFU-E formation, in addition to inadequate ESF production, plays an important role in renal anemia.

Adult↗
PubMed1985

Spontaneous glomerular IgA deposition in ddY mice: an animal model of IgA nephritis.

It was found that ddY mice derived from non-inbred dd-stock mice brought from Germany before 1920 and then raised in Japan developed spontaneously IgA dominant deposition in the glomerular mesangium. In this report we give a detailed natural history of the renal pathology of those mice. The animals were fed rodent laboratory chow and sacrificed in groups of 9 to 10 at 6, 10, 16, 24, 28, 40, and 59 weeks of age. The bladder urine was analyzed, serum immunoglobulins were measured, and the kidney specimens were evaluated with light, fluorescent, and electron microscopy. Proteinuria was (plus) to (2 plus) after 28 weeks and (2 plus) to (3 plus) at 59 weeks with negative hematuria. Mesangial cell proliferation began to appear at 16 weeks, then progressed to a definite proliferative glomerulonephritis. At 59 weeks an additional increase of the mesangial matrix occurred. By immunofluorescence, there were IgG of (2 plus), IgM (plus) to (2 plus), IgA (plus) and C3 (plus) in the glomeruli until 28 weeks. However, IgA started to be dominant at 40 weeks and the glomerular pattern was IgA (2 plus) to (3 plus), IgG (plus) to (2 plus), IgM (+/-) to (plus) and C3 (plus) to (2 plus) at 59 weeks. Polyclonal IgA and IgG2a among immunoglobulins steeply rose at 40 weeks, and at 59 weeks IgA increased by 850%, IgG2a by 280%, IgG1 by 170%, IgG2b by 90%, and IgM by 60%, as compared with their level at 6 weeks. There was no anti-nuclear antibody. Thus, ddY mice, at least after the age of 40 weeks, can be used as a new animal model for spontaneous IgA nephritis. The probable origin of IgA is also discussed.

Animals↗
PubMed1985

IgM monoclonal gammopathy accompanied by nodular glomerulosclerosis, urine-concentrating defect, and hyporeninemic hypoaldosteronism.

A 54-year-old male had monoclonal IgM-kappa light chains in the serum and free monoclonal kappa light chains in the urine. Renal biopsy revealed nodular glomerulosclerosis associated with the accumulation of kappa light chains. Isolated microscopic hematuria was present for over 1 year. He also showed a defect in urine concentration for which the light chains deposited along the basement membrane in the inner medullary tubules were judged to be responsible. When the glomerular filtration rate fell to 30 ml/min, the syndrome of mild renal failure, decreased potassium excretion, and hyporeninemic hypoaldosteronism developed, suggesting that kappa light chain nephropathy is a cause of this syndrome. Chemotherapy appeared to have some beneficial effects in maintaining renal function.

Aldosterone↗
PubMed1984

Radiation-induced fibrosarcoma of the thyroid.

A rare thyroid tumour is described. It started as a papillary cytoadenoma 20 years ago, followed by the appearance of a papillary adenocarcinoma 6 years later. At that time most of the tumour was excised, except for a small portion which had invaded the trachea. Post-operatively 6,000 rads of Co60 was given to the neck; the tumour remained quiescent for 18 years until two years ago, when a recurring fibrosarcoma appeared in her neck. It is suggested that this tumour was a radiation-induced sarcoma.

Carcinoma, Papillary↗
PubMed1984

Renal involvement patterns of amyloid nephropathy: a comparison with diabetic nephropathy.

Thirty kidney specimens obtained from 26 patients with intrarenal amyloid deposition were evaluated. The deposited amyloid belonged to AL protein in 15 cases and AA protein in 11. The intrarenal distribution was examined. Intraglomerular nodular pattern showed a wider extraglomerular distribution of amyloid with a florid accumulation along the vasa recta in the outer medulla, whereas intraglomerular diffuse pattern had amyloid deposition confined mainly to a narrow range surrounding the glomeruli. However, no essential difference was appreciated between AL and AA proteins in the intrarenal distribution, although the former more often disclosed the diffuse pattern. There were many morphological expressions resembling diabetic nephropathy; in addition to the diffuse and nodular pictures, capsular drop-like deposits along Bowman's capsule, simultaneous deposition in the afferent and efferent arterioles, glomerular microaneurysm of early stage, and accumulation along the tubular basement membrane were observed in amyloid nephropathy. Thus, the spicule formation in renal amyloidosis and the diffuse thickening of glomerular and tubular basement membranes in the diabetic emerged as the respective specific lesion. The implicated pathogenesis of diabetic nephropathy was also discussed.

Adult↗
PubMed1983

Local cerebral glucose utilization in epileptic seizures of the mutant El mouse.

The neural pathway and the focus of the epileptic seizure of mutant El mice were studied by the [14C]2-deoxyglucose technique. In the mice with full tonic-clonic seizure, the entire neocortex and hippocampus showed a remarkably increased metabolic rate. By contrast, a lower metabolic rate was evident in the thalamic nuclei, central gray, locus coeruleus and some interstitial nuclei. The epileptic focus in El mice presumably exists in the hippocampus.

Animals↗
PubMed1983

Tobramycin inactivation by carbenicillin, ticarcillin, and piperacillin.

The in vitro and in vivo inactivation of tobramycin by carbenicillin, ticarcillin, or piperacillin was investigated by the enzyme immunoassay method in clinically employed dosages. After the addition of an 80-mg dose of tobramycin to 4- to 5-g doses of a penicillin in 100 ml of 0.9% saline or distilled water, the degradation profile of tobramycin appeared to follow a biexponential pattern of decay. Remarkable losses (30 to 40%) of tobramycin combined with carbenicillin or ticarcillin were observed within 1 h, as compared with the later decline. The combination of tobramycin with piperacillin was least inactivating. When the admixture of tobramycin with carbenicillin or piperacillin used in the in vitro study was infused to six volunteers over 1 h, the observed maximum concentrations of tobramycin were on the average 66 and 74% for carbenicillin and piperacillin, respectively, of that observed after tobramycin alone was given. In contrast, the value obtained for tobramycin in combination with piperacillin was close to 90% of the control value. The elimination half-lives of tobramycin combined with the penicillins were slightly shorter than those of tobramycin alone, indicating that the interaction occurs even in patients with normal renal function.

Adult↗
PubMed1983

Pseudothrombocytopenia and IgA-related platelet agglutinin in a patient with IgA nephritis.

A 41-year-old female was evaluated for asymptomatic proteinuria and thrombocytopenia. The renal biopsy disclosed mild to moderate mesangial proliferation, and the immunohistology showed granular deposition of dominant IgA and C3 in the mesangium, which is consistent with IgA nephritis. Thrombocytopenia was EDTA-dependent pseudothrombocytopenia type 1. Heparinized blood restored the platelet count to normal. Serological examinations revealed that the platelet agglutinin was IgA, and the platelet clumping required both EDTA and IgA-related agglutinin. Thus, the present case adds the combination of IgA nephritis and pseudothrombocytopenia to the spectrum of the so-called thromborenal syndrome. In view of recent findings that platelet agglutinins belong to immunoglobulins or fractions, occurring frequently in a variety of immunologically abnormal situations, IgA-related agglutinin as seen in this patient may have more than a chance association with IgA nephritis.

Adult↗
PubMed1983

Pharmacokinetics of a sustained-release theophylline preparation in healthy subjects.

A comparative pharmacokinetic study between a sustained-release theophylline tablet (Theona) and aminophylline powder following multiple oral administrations every 12 h at a 200 mg theophylline dose was performed in ten healthy adult volunteers. As the results, theophylline in Theona revealed almost completely absorbed as is aminophylline. A peak-trough difference with Theona was less than half of that with aminophylline powder. These results suggest that Theona has excellent characteristics as a sustained-release preparation. In addition, in order to investigate dose-dependent kinetics for theophylline, the relationship between average plasma level and dosage was examined with Theona. The plasma level showed proportional change at the low concentrations. When the plasma level was close to 10 micrograms/ml, however, dosage increment results in an increasingly greater change of plasma level, which may indicate a high risk of toxicity.

Adult↗
PubMed1983

Enhancement of lymphatic transport of 1-(2-tetrahydrofuryl)-5-fluorouracil by polyacrylic acid aqueous gel and emulsion type suppositories in rats.

1-(2-Tetrahydrofuryl)-5-fluorouracil (FT-207) concentrations in lymph and plasma were measured after rectal administration of three types of suppositories containing FT-207. The suppositories used in this study were prepared from polyacrylic acid aqueous gel bases, emulsion type bases and a commercial fat base, witepsol w-35. Both aqueous gel and emulsion type suppositories were superior to the suppositories from witepsol with regard to FT-207 concentration in lymph and plasma. The addition of aqueous gel to the polyacrylic acid aqueous gel was found to be effective for the lymph transport from the aqueous gels. Polyacrylic acid aqueous gel containing 1% glycyrrhizin was better than other suppositories. Solidification of the emulsion type bases are also investigated, and it is suggested that these may be better substitutes of the oily suppository.

Acrylic Resins↗