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Biomedical subjects

Y Orita

Publications and source records attributed to Y Orita.

At least 199 records · Page 11Linked to original sources
PubMed1979

Effect of low protein diet and surplus of essential amino acids on the serum concentration and the urinary excretion of methylguanidine and guanidinosuccinic acid in chronic renal failure.

20 patients with moderate renal failure (serum creatinine 4.5--12.0 mg/dl) and some uremic symptoms on a diet ad libitum were treated with a high caloric diet containing 0.5--0.7 g/kg/day protein, supplemented with eight essential amino acids and histidine in the form of solution and/or granules. During the treatment uremic symptoms subsided or diminished without the signs of malnutrition, SUN and the ratio SUN/S-creatinine fell and the nitrogen balance and the ratio N-balance/intake N improved. The serum concentration and the urinary excretion of MG and GSA of the 12 patients were determined by Stein's method using the modified Sakaguchi reaction. In all patients, the serum concentration and the urinary excretion of MG and GSA diminished remarkably during the treatment with a low protein diet alone and furthermore with a low protein diet and essential amino acid supply. We concluded that conservative treatment -- low nitrogen diet supplemented with sufficient calories and essential amino acids -- improved the nutritional state of uremic subjects, and decreased the metabolic production of MG and GSA. The results show that the supplementation of essential amino acids to uremic patients may be a useful treatment.

Adult↗
PubMed1978

Effect of arginine or creatinine administration on the urinary excretion of methylguanidine.

The metabolic pathway of methylguanidine (MG) is mainly speculated from the change in urinary excretion of MG in the arginine (Arg)-injected normal rat, the creatinine (Cr)-injected normal rat, and the Arg-injected uremic rat. 15N-Arg was ingested to 2 uremic patients. Arg administration resulted in marked increase in urinary MG excretion both in the uremic rat and patient, but not in the normal rat. In the first phase of the 15N-Arg ingestion experiment, a rapid rise of 15N atom percent excess of urinary MG was observed in the uremic patient. In the second phase of this study, after 24 h of 15N-Arg ingestion, the 15N atom percent excess of urinary Cr and that of MG closely paralleled. These findings imply that there might be two metabolic origins of MG: one is a formation of MG from Arg itself or an Arg metabolite other than Cr, the other a pathway producing MG via Cr. The former is compatible with the hypothesis by Cohen.

Animals↗
PubMed1977

Immunofluorescent studies of urinary casts.

Immunofluorescent staining of urinary casts of patients with chronic glomerulonephritis or with acute renal failure was performed. Urinary and cast Tamm-Horsfall mucoproteins were purified by a modified McQueen's method. Rabbits were immunized by both of these materials to obtain antisera. The antigenic specificity of the prepared material was examined by Ouchterlony gel diffusion method and immunoelectrophoresis. Indirect and direct immunofluorescent staining methods were done using Tamm-Horsfall mucoprotein antiserum and FITC-GARG, FITC-labelled IgG, IgA, IgM, C3 and albumin. Hyaline casts of both chronic glomerulonephritis and acute renal failure demonstrated fluorescence with Tamm-Horsfall mucoprotein antiserum. The nature of the granular casts of chronic glomerulonephritis seemed to be different from those of acute renal failure because the granules of the former fluoresced for some serum protein fractions, but the latter fluoresced only for Tamm-Horsfall mucoprotein. The absence of fluorescence with epithelial casts for any serum protein fractions implied a different pathogenesis for epithelial casts as compared to granular casts, contrary to Lippman's assumption. A routine technique of immunofluorescent staining of urinary casts was developed. The interpretation of urinary casts should be more specific by this new technique.

Acute Kidney Injury↗
PubMed1977

Baroreflex sensitivity in patients with Takayasu's aortitis.

Takayasu's aortitis is an arterial inflammatory disease of arteries of unknown etiology. Fainting is a common symptom and has been attributed to ypersensitivity of the baroreflex. We studied baroreflex sensitivity in 11 patients with Takayasu's aortitis and compared it with that of eight control subjects of comparable age. Baroreflex sensitivity was assessed by determining the slope of a regression line relating the rise of systolic arterial pressure to the prolongation of the R-R interval of the electrocardiogram during a transient rise of arterial pressure induced by an intravenous injection of phenylephrine. The average baroreflex slope of patients with Takayasu's arteritis (4.0 +/- 0.8 msec/mm Hg) was significantly less than that of control subjects (10.7 +/- 0.8 msec/mm Hg, P less than 0.001). Reduced baroreflex sensitivity in patients with Takayasu's aortitis may be due to the hardening of the arteries where baroreceptors lie, or to hypertension and/or cardiac disease which was present in most of the patients included in this study. Patients with Takayasu's aortitis who complained of fainting also showed the reduced baroreflex sensitivity. This indicates that fainting in this disease is not likely to be caused by the hyperreactivity of the baroreceptors as is commonly postulated.

Adult↗
PubMed1977

Effect of supplementation of limiting amino acids on tyrosine toxicity in rats fed wheat gluten diets.

The effect of supplementation of limiting amino acids on rats fed a 10 or 20% wheat gluten diet containing 5% tyrosine has been investigated. Growth-limiting amino acids in a 20% wheat gluten diet were lysine and threonine. When rats were fed a 20% wheat gluten diet containing excess tyrosine, the addition of 1.0% lysine-HCl or 1.0% lysine-HCl and 0.4% threonine completely prevented the development of tyrosine toxicity, and was accompanied by a lowering of free tyrosine concentrations in plasma, liver and muscle. In rats receiving a 10% wheat gluten diet, lysine, threonine and methionine were limiting for growth. The addition of 1.0% lysine-HCl to the 10% wheat gluten plus 5% tyrosine diet failed to alleviate the tyrosine toxicity, but the supplement of 1.0% lysine-HCl and 0.4% threonine could partially alleviate the toxicity. The combined addition of 1.0% lysine-HCl, 0.4% threonine and 0.5% methionine was most effective. The free tyrosine concentrations in plasma, liver and muscle were lowered greatly by the supplementation of three limiting amino acids, but amounts of free tyrosine and phenolic metabolites excreted in the urine did not decrease with addition of these limiting amino acids.

Amino Acids↗