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Biomedical subjects

Y Miyake

Publications and source records attributed to Y Miyake.

At least 559 records · Page 31Linked to original sources
PubMed1986

Human urinary prokallikrein: rapid purification and model activation by trypsin.

With only a three-step chromatographic procedure, human urinary prokallikrein has been purified completely. The active kallikrein also could be purified in the process of this purification. The prokallikrein was very rapidly activated by trypsin, followed thereafter by a very slow increase in the kallikrein activity. In the rapidly activated state, the molecular weight and the values of Km and Vmax were very similar to those of the purified active kallikrein. Only the slow increase in the activity was observed by tryptic digestion of the active kallikrein. The results suggest that the initial rapid activation is due to release of the propeptide and the slow reaction is due to a limited hydrolysis of the activated prokallikrein at sites which are not directly related to the active site.

Chromatography, Affinity↗
PubMed1985

Experimentally produced sinusoidal fetal heart rate pattern in the chronically instrumented fetal lamb.

A sinusoidal fetal heart rate and elevated fetal arginine vasopressin levels were found in two bled fetal lambs. Arginine vasopressin was continuously infused intravenously in chronically instrumented fetal lambs at rates ranging between 1.0 and 90 mlU/kg/min. No sinusoidal heart rate occurred in 21 experiments on six control animals with intact vagal nerves. Atropine at doses less than 0.4 mg had no effect (six experiments on three animals). Higher doses of atropine (greater than 1.2 mg) resulted in sinusoidal heart rate (24 experiments on six animals). Twenty-three infusions were performed in five bilaterally vagotomized fetuses, and the sinusoidal heart rate was successfully induced in 17 experiments. The arginine vasopressin infusion rate was less than 1.5 mlU/kg/min on the six occasions in which the sinusoidal heart rate did not appear. All sinusoidal heart rate patterns were associated with fluctuation of fetal arterial pressure at the same frequency. There was a linear correlation between the amplitude of sinusoidal heart rate and magnitude of arterial blood pressure fluctuation. The amplitude of sinusoidal heart rate increased with the concentration of arginine vasopressin infused. Modification of sinusoidal heart rate pattern was attempted with use of sympathetic agonists and antagonists. The possible etiology and mechanisms of sinusoidal heart rate pattern are discussed.

Animals↗
PubMed1985

Temporal aspects of the electroretinogram in cone-rod dystrophy.

Twelve patients with cone-rod dystrophy were studied in terms of the temporal aspects of electroretinography (ERG). The peak time of scotopic b-wave was within normal limits in all patients, while the amplitude was reduced in nine patients. The normal peak time of the scotopic-b wave may help explain rod involvement with normal or only slightly elevated final rod thresholds of subjective dark adaptation. The peak time of photopic b-wave and 30-Hz flicker response was normal in four patients and significantly delayed or nonrecordable in eight patients. Such variations of peak time in photopic and 30-Hz flicker ERG may reflect the stage of the disease or may be caused by the different hereditary mode.

Adult↗
PubMed1985

Cells of a human monocytic leukemia cell line (THP-1) synthesize and secrete apolipoprotein E and lipoprotein lipase.

A human cell line established from a patient of an acute monocytic leukemia (THP-1) retained an ability to synthesize and secrete plasma apolipoprotein E like protein. The protein was identified with monospecific antibody raised against human plasma apolipoprotein E. The cells also secreted lipoprotein lipase (EC 3.1.1.34). The enzyme was characterized as lipoprotein lipase on the basis of the requirement of apolipoprotein C-II as an activator and the inhibition of its activity by sodium chloride. The secretion of both apolipoprotein E and lipoprotein lipase was markedly enhanced in the process of differentiation into macrophage-like cells by the addition of 4 beta-phorbol 12 beta-myristate 13 alpha-acetate.

Apolipoprotein C-II↗
PubMed1985

Differential diagnosis of congenital tritanopia and dominantly inherited juvenile optic atrophy.

To determine whether congenital tritanopia and dominantly inherited juvenile optic atrophy (DIJOA) are the same clinical entity, we used electroretinograms of the blue-sensitive cone system (blue cone ERGs), comparing those of two patients with congenital tritanopia from two pedigrees with those of four patients with DIJOA from two pedigrees. The examinations also included visual acuity and visual field tests, fundus examination, the dark-adaptation test, and several color vision tests. The blue cone ERG confirmed a difference between the two groups; it was unrecordable in the patients with congenital tritanopia but within the normal range in those with DIJOA. We believe that congenital tritanopia and DIJOA are distinct disease entities and that the blue cone ERG is a key factor in the differential diagnosis.

Adult↗
PubMed1985

Crystallization of excipients in tablets.

Whisker-like crystals appeared on the surface of tablets that contained lactose or mannitol, a hygroscopic material such as docusate sodium, magnesium chloride, or potassium acetate, and other ingredients stored in an atmosphere of high relative humidity. The crystals were observed under a scanning electron microscope and were measured using differential scanning calorimetry and TLC. The crystals contained lactose or mannitol.

Calorimetry, Differential Scanning↗
PubMed1985

Effects of dose, pH, and osmolarity on nasal absorption of secretin in rats.

The effects of dose, pH, and osmolarity on the nasal absorption of a secretin solution were studied in rats. The nasal absorption of secretin was determined by measuring the increased secretion of pancreatic juice, and this was compared with the same response on intravenous administration. The relative bioavailability of secretin on intranasal administration compared with intravenous administration, as estimated from the pharmacological response, was approximately one-tenth. It was enhanced in acid solution and reached a maximum in a 0.462 M sodium chloride solution.

Absorption↗
PubMed1985

Ability of enzymes to remove Candida.

Infection by C. albicans is a significant cause of denture stomatitis. Therefore, the results of this study, which demonstrated that yeast lytic enzymes and proteolytic enzymes removed C. albicans from acrylic resin surfaces, suggest that these compounds are potentially useful denture cleansers.

Acrylic Resins↗
PubMed1985

A study on renin binding protein (RnBP) in the human kidney.

We purified, from human kidney, a protein that reacts with rabbit anti-porcine kidney renin binding protein (RnBP) antiserum by trapping with porcine kidney renin. The purified preparation showed a single protein peak on gel filtration by high performance liquid chromatography (HPLC) and two protein bands on sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The latter two kinds of protein were identified as the porcine renin and human kidney protein from their electrophoretic mobilities and reactivity toward rabbit anti-porcine kidney renin and RnBP antisera. The molecular weights of the purified preparation and the human kidney protein were estimated to be 56,000 by HPLC and 43,000 by SDS-PAGE, respectively. The specific activity of porcine renin in the purified preparation was 8.6 mg angiotensin I per mg of protein per h at 37 degrees C and pH 6.5. This specific activity was about one-fifth that of free porcine renin. Therefore, it is suggested from the reactivity toward the anti-porcine RnBP antiserum and inhibitory action toward porcine renin that the human kidney protein is RnBP and that the human RnBP is purified as a complex with porcine renin.

Animals↗
PubMed1985

A spin-label study on human high density lipoprotein.

Human plasma high density lipoproteins (HDL) have been labeled with N-(1-oxyl-2,2,6,6-tetramethyl-4-piperidinyl)maleimide (NEM-TEMPO). The spin-labeled HDL exhibited an ESR spectrum containing signals of both strongly immobilized and weakly immobilized components by the reaction with a high concentration of NEM-TEMPO, while an ESR spectrum containing only signals of a strongly immobilized component range between 4 degrees C and 37 degrees C, the signal height of the strongly immobilized component exhibited reversible temperature-dependent changes, whereas that of the weakly immobilized component changed irreversibly at temperatures above 25 degrees C. The activation energy of the irreversible change was estimated to be 26 kcal per mol. The strongly immobilized component was derived from NEM-TEMPO which modified apolipoprotein A-I covalently, while the weakly immobilized component was derived from NEM-TEMPO noncovalently bound to HDL. The rate of binding of NEM-TEMPO to either the strongly binding or weakly binding sites and the number of the strongly binding sites in apolipoprotein A-I were estimated to be 125 M-1.day-1 and 1.78, respectively. The binding of NEM-TEMPO to the strongly binding sites was suppressed greatly by pretreatment of HDL with 2,4,6-trinitrobenzene sulfonic acid (TNBS). The slow reaction and suppression with TNBS suggest that NEM-TEMPO binds to some amino acid residue, probably a lysine residue, in apoprotein A-I. The strongly immobilized and weakly immobilized components were reduced almost completely by ascorbate at the same rate, 0.048 min-1 at pH 7.4 and at 4 degrees C.

Ascorbic Acid↗
PubMed1985

Rate of cholesteryl ester transfer between high and low density lipoproteins in human serum and a case with decreased transfer rate in association with hyperalphalipoproteinemia.

The rate of cholesteryl ester transfer between intrinsic high and low density lipoproteins (HDL and LDL) was measured in human serum in the absence of lecithin:cholesterol acyltransferase (LCAT) and very low density lipoproteins. The rate was calculated according to the equilibrium transfer model between the two lipoprotein cholesteryl ester pools. The average rate of the transfer was 213 +/- 95 nmol/h/ml (mean +/- S.E.) for all 20 normal and 13 hyperlipoproteinemic subjects. The transfer rate in individual serum was higher by several times than the cholesterol esterification rate, showing that cholesteryl ester generated by LCAT on HDL is promptly distributed among various lipoprotein subclasses. The rate of cholesteryl ester transfer in the serum was significantly proportional to the product of intrinsic HDL and LDL concentrations, a possible indicator of the frequency of collision between these lipoproteins, for the range of physiological lipoprotein concentrations. Among the subjects analyzed was a patient with remarkable hyperalphalipoproteinemia accompanied by hypertriglyceridemia, who showed a very low rate of cholesteryl ester transfer in relation to his LDL and HDL concentrations. Compositional analysis of lipoprotein lipids of the patients also supported the possibility of impaired neutral lipids transfer activity among lipoproteins in the blood.

Adult↗