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Biomedical subjects

M Yakata

Publications and source records attributed to M Yakata.

At least 73 records · Page 4Linked to original sources
PubMed1983

Three families with fast bisalbuminaemia.

We describe three cases of familial (SH, AY, and TM) fast-type bisalbuminaemia identified from 300 000 electrophoretic strips screened during the past six years. The immunological antigenicity and chemical composition of the isolated fast and normal albumins were essentially indistinguishable in all three cases. Detailed analyses on one of them (TM) by circular dichroism and fluorescent spectra measurements indicated that there was a marked change in the environment of the single tryptophan residue of the fast albumin, suggesting an alteration in the tertiary structure of the molecule. It is likely that this abnormality of the tertiary structure modulated (perturbed) the distribution of electric charges on the protein surface and thus changed its electrophoretic mobility.

Aged↗
PubMed1983

Clinical evaluation of the liquid-chromatographic determination of urinary free cortisol.

We recently reported (Clin. Chem. 28: 1497-1500, 1982) a liquid-chromatographic method for quantifying free cortisol in urine. We have since evaluated the clinical utility of our method by assaying cortisol in urine from normal subjects, patients, and subjects undergoing endocrine tests. We found that, in contrast with plasma cortisol, urinary cortisol is not bound to protein. It shows some correlation with 17-hydroxycorticosteroids in urine, but is independent of creatinine excretion. The amount of cortisol excreted daily by a particular individual was found to be fairly constant during nine or 10 days. Normal values determined for 203 apparently healthy individuals were 35.8 (SD 18.7) micrograms/day, with no significant sex-related differences but a tendency for a gradual decrease of cortisol excretion with age. We also report urinary cortisol excretion by patients with pituitary-adrenal disorders and some other diseases, and the pattern of response to dexamethasone and metyrapone administration.

Adolescent↗
PubMed1982

Two-cycle liquid-chromatographic quantitation of cortisol in urine.

When the free cortisol in urine was analyzed by liquid chromatography after pretreatment with the usual organic extraction, interfering substances having chromatographic behavior similar to that of cortisol and the internal standard precluded accurate measurement. To remove these materials, we processed the organic extract by liquid chromatography with a normal-phase column for clean-up; the specific cortisol fraction and the internal standard collected in the effluent were then subjected to liquid chromatography with a reversed-phase column. The "two-cycle" chromatograms thus obtained were sufficiently specific for the quantitation of urinary cortisol. The method clearly detects cortisol in urine at a minimum concentration of about 5 micrograms/L when 1 mL of urine is extracted. The mean urinary free cortisol in apparently healthy individuals was 40.9 (SD 17.7) micrograms/day (n = 32) by this method.

Adult↗
PubMed1982

Urine contains an inhibitor for turbidimetric determinations of protein.

Our examination of urine components separated by gel filtration revealed the presence of an inhibitor that decreases the analytical recovery of protein in a turbidimetric assay involving sulfosalicylic acid as reagent (Proc. Soc. Exp. Biol. Med. 92: 748, 1956). The apparent relative molecular mass of this inhibitor was in the range 160 000-240 000. A study with purified proteins showed a similar inhibition by gamma-globulin, glycoprotein, and beta-lipoprotein in the assay of albumin by the same turbidimetric method. In contrast, measurement of protein by a dye binding method was not affected by these materials. The low values for apparent urinary protein given by the turbidimetric method as compared with those by the dye-binding method are at least partly ascribable to the inhibitor.

Albuminuria↗
PubMed1980

Thyroid hormone metabolism in patients with liver cirrhosis, as judged by urinary excretion of triiodothyronine.

This study included 35 patients with liver cirrhosis, 23 patients with hyperthyroidism, 12 with hypothyroidism, and 2 with other endocrine disorders. In the various endocrine disorders an appreciable amount of triiodothyronine (T3) was excreted into the urine but the daily excretion was fairly constant in each patient. Urinary excretion of T3 was negligible or depressed in hypothyroidism, but increased with a rise in the serum level of T3. Serum and urinary T3 decreased in liver cirrhosis, but the serum thyroxine (T4) level was within the normal range. When the cirrhosis patients were divided into 3 groups according to the urinary excretion of T3, a decrease of urinary T3 was associated with a decrease in the serum levels of T3 and free T3. An increase of serum thyroid-stimulating hormone (TSH) either before or after injection of thyrotropin-releasing hormone (TRH) was inversely correlated with a decrease of serum and urinary T3. The decrease of serum and urinary T3 was correlated with the magnitude of lh a decrease in the serum levels of T3 and free T3. An increase of serum thyroid-stimulating hormone (TSH) either before or after injection of thyrotropin-releasing hormone (TRH) was inversely correlated with a decrease of serum and urinary T3. The decrease of serum and urinary T3 was correlated with the magnitude of lh a decrease in the serum levels of T3 and free T3. An increase of serum thyroid-stimulating hormone (TSH) either before or after injection of thyrotropin-releasing hormone (TRH) was inversely correlated with a decrease of serum and urinary T3. The decrease of serum and urinary T3 was correlated with the magnitude of liver damage as judged by indocyanine green retention and a decreased urinary excretion of cyclic adenosine 3',5'-monophosphate. In vitro experiments indicated that rat liver, as compared to the kidney, heart and skeletal muscle, strongly converts T4 to T3, but this activity is greatly reduced by liver damage induced by ligation of the bile duct. It is suggested that patients with liver cirrhosis are, to some extent, in a state resembling subclinical hypothyroidism because of inability of the liver to metabolize a sufficient amount of T3 from T4.

Adult↗