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Biomedical subjects

Z Saito

Publications and source records attributed to Z Saito.

At least 19 recordsLinked to original sources
PubMed1994

[Analysis of synthetic corticoids by high performance liquid chromatography].

High performance liquid chromatography (HPLC) has been developed to analyze the synthetic corticoids (SCS) in human biological fluids. First, steroid moiety was extracted with a chemical solvent and/or an octadecylsilan (or diatomaceous earth) column, then the extracts were separated on the ordinary or reversed phase HPLC column with ultraviolet detection, at 254 nm. The total automatic system for the HPLC method has improved the accuracy and precision of SCS measurement for clinical use. Protein binding and free steroids, assayed by HPLC in plasma and saliva of the subjects treated with SCS may relate to steroid sensitivity. On the other hand, the simultaneous analysis of the metabolites of SCS in urine and other fluids reveals the clinical activity of the given SCS. HPLC analysis can therefore be utilized for evaluation of SCS pharmacodynamics.

Chromatography, High Pressure Liquid↗
PubMed1993

Purification and some properties of proteinase from Pseudomonas fluorescens No. 33.

The extracellular proteinase from Pseudomonas fluorescens No. 33 was purified to electrophoretic homogeneity by a procedure including precipitation with HCl and (NH4)2SO4, and column chromatography. The enzyme was purified 170-fold giving a yield of 7% of the original activity. The molecular mass of the purified enzyme was 48,000 by SDS-PAGE. The optimum pH and temperature for the hydrolysis of casein were 8.0-9.8 and 30-35 degrees C respectively. The enzyme was more thermostable in synthetic milk salts solution than in 0.1 M-sodium phosphate buffer, but was heat-labile at 50 degrees C in both buffer systems. The activity was inhibited by o-phenanthroline, Hg2+, Cu2+, Fe2+ and, to a lesser extent, Ni2+. Caseins were susceptible to the proteinase, but degradation patterns were dependent on the form of the casein.

Caseins↗
PubMed1993

Influence of milk proteins on the thermostability of the lipase from Pseudomonas fluorescens 33.

The effects of some milk proteins on the thermostability of the lipase from Pseudomonas fluorescens 33 were investigated. All purified milk protein fractions except kappa-casein that dissolved in phosphate buffer were effective for thermostabilization of the lipase. Thermal behavior of the lipase containing beta-lactoglobulin was so specific that, after heating at 80 to 90 degrees C, activity remained high and was comparable with that of unheated treatment. The thermostability of the lipase containing whey proteins in synthetic salts solution was extensively lowered, but that containing casein micelles retained 50% of original activity after heat treatment at 80 degrees C for 10 min. Low temperature inactivation of the lipase was influenced by concomitant milk proteins.

Caseins↗
PubMed1988

[Aldosterone metabolites in spontaneously hypertensive rats].

Several aldosterone metabolites are now known to possess some mineralocorticoid activities. In order to test the hypothesis that these metabolites could contribute to the pathogenesis of hypertension, we studied the aldosterone metabolism in SHR in vitro and in vivo. In vitro experiment, male SHR and WKY rats of 4 and 15 weeks of age were used. The microsome, cytosol and heavy mitochondria fractions from liver and kidney were isolated by ultracentrifuge. 10mg protein/ml of each subcellular fraction was incubated with 3H-aldosterone in Tris-HCl buffer at pH 7.4 containing NADPH, glucose-6-phosphate (G-6-P) and G-6-P dehydrogenase as described by Morris, D.J. et al. (Hypertension, 5 (suppl. I]: I-35-I-40, 1983.). Aldosterone and its metabolites synthesized were extracted with Sep-pak C18 cartridges and separated by HPLC on a reverse phase column. In vivo experiments, the urine of male SHR and WKY rats of 15 weeks old injected 10 microCi 3H-aldosterone intraperitoneally was collected for 48 hours, extracted and analyzed by HPLC. Peaks of steroids from SHR were compared with those from WKY. Incubation of aldosterone with liver microsomes yielded at least 10 polar and 3 less polar metabolites (A-ring reduced metabolites). SHR liver microsomes synthesized larger amounts of 3 polar metabolites than WKY liver microsomes. Liver cytosol, liver heavy mitochondria and kidney subcellular fractions mainly synthesized less polar metabolites, but failed to synthesize as much polar metabolites as liver microsomes. Kidney microsomes and cytosol from 4 weeks old SHR synthesized larger amounts of less polar metabolites compared to those from WKY. In vivo experiment, SHR of 15 weeks of age excreted larger amounts of 2 polar metabolites than WKY. The present study suggests that the difference of metabolism of aldosterone between SHR and WKY observed from an early stage in the liver and the target organ, kidney, may be associated with hypertension or its causative factors, and confirms that aldosterone will be metabolized to several polar and less polar forms by rat liver and kidney subcellular fractions.

Aldosterone↗
PubMed1985

Cushing's syndrome associated with bilateral adrenal adenomas.

The fifth case of Cushing's syndrome with bilateral adrenocortical tumours is described. By the hormonal dynamic studies both tumours have been shown to be autonomous in the secretion of cortisol. Histopathologically, both tumours were identified as benign adrenocortical adenomas without nodules, and the right one was a so-called black adenoma. A high concentration of cortisol was obtained from both tumour tissue extracts. The differential diagnosis of Cushing's syndrome due to bilateral adrenocortical adenomas from primary adrenocortical nodular dysplasia is briefly discussed.

Adenoma↗
PubMed1983

Analysis of corticosteroids in human adrenal tissue by high pressure liquid chromatography.

High pressure liquid chromatography (HPLC) was demonstrated to be a good tool for the separation, identification and quantitation of corticosteroids (CS) extracted from homogenized tissue of adrenal glands and adrenal tumors in patients with hypercorticism. A chromatographic system consisting of Sorbax-SIL and Sorbax-CN columns, organic solvent extraction and a UV detector was used to analyze both more polar and less polar corticosteroids in the adrenal tissue.

Adrenal Cortex Hormones↗
PubMed1982

[Total blood volume in essential and secondary hypertension].

To study the role of volume factors in the pathogenesis of hypertension, total blood volume (TBV) was determined in 43 patients with essential hypertension, 10 with primary aldosteronism, 5 with Cushing's syndrome, 5 with renovascular hypertension and 23 age-matched normotensives. The radioisotope (131I) labeled plasma tracer technique was employed under conditions of constant sodium intake (200mEq/day). The TBV values obtained were expressed as % normal against the predicted values according to the formulae of Fujita and his co-workers. The results were as follows: (1) TBV was increased in patients with primary aldosteronism. (2) In essential hypertensive patients, with either normal or low plasma renin activity, TBV was normal. (3) There was no increment of TBV in patients with Cushing's syndrome. These results suggest that expanded intravascular volume plays a major role in the mechanism of hypertension with suppressed plasma renin activity in primary aldosteronism, whereas other unknown factors may be related to the causes of hypertension in patients with essential hypertension and Cushing's syndrome.

Adult↗
PubMed1979

[The high pressure liquid chromatography of corticoids. II. Analysis of synthetic corticoids in blood and urine (author's transl)].

The high pressure liquid chromatographic (HPLC) technique was developed to separate and quantitate the synthetic corticosteroids (s-CS) which are widely used clinically. 1) 12 kinds of s-CS in alcoholic solvent and 2) some of their metabolites in the plasma and urine of healthy subjects with oral administration of s-CS were investigated for the preliminary work. The results are summarized as follows: 1) Cortisol sodium phosphate, Dexamethasone 21, disodium phosphate, Paramethasone acetate, Cortisol acetate, Cortisone acetate, Methylprednisolone acetate, Prednisone, Dexamethasone, 9 alpha-fluorocortisol, Betamethasone, Triamcinolone, and Prednisolone in ethanol were clearly separated by HPLC from Cortisol (F). In the suitable condition of the HPLC (LC-2 type) with a Zorbax SIL column, organic solvent (cyclohexane:dichloromethane:ethanol = 9:4:1)-carrier mobile phases and UV detector, the retention time of each s-CS was obviously different from that of F. The calibration curve was obtained in a linear line with regards to each s-CS. The mean recovery was 97.6% and the coefficient of variation were 1.6 (intraassay) and 7.2 (interassay)%. The sensitivity of the steroid determination was 200pg order. 2) The serial changes in plasma concentrations of s-CS; CS-metabolites and endogenous F were shown in 3 healthy males and 2 females following oral administration of the s-CS. The separated metabolites in number and quality depended on the kind of s-CS. Prednisone and other kinds of the acidified products were separated from prednisolone in the plasma and urinary samples of the healthy subjects as well as Addisonian patients. In conclusion, the HPLC method is useful for the separation and quantitation of the UV-absorbing CS of human plasma and urine. The obtained chromatograms may be an indication of the metabolic state of the subject with treatment of s-CS.

Adrenal Cortex Hormones↗