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Biomedical subjects

E Miyamoto

Publications and source records attributed to E Miyamoto.

At least 235 records · Page 13Linked to original sources
PubMed1981

Occurrence of two types of Ca2+-dependent protein kinases in the cytosol fraction of the brain.

Two types of Ca2+-dependent protein kinases were demonstrated and partially purified from the cytosol fraction of rat brain by DEAE-cellulose, Sephadex G-200, and calmodulin-affinity column chromatography, using endogenous proteins and chicken gizzard myosin light chains as substrates. The molecular weights of the enzymes were 88,000 (peak I) and 120,000 (peak II) on gel filtration. Peak I had no affinity for calmodulin, whereas peak II had a high affinity for it, with a Ka value of 16.7 nM. The Ka values of peaks I and II for Ca2+ were 2.4 and 1.6 microM, respectively.

Animals↗
PubMed1981

Cranial chondromyxoid fibroma. Case report.

A case of chondromyxoid fibroma of the frontal bone in a 15-year-old girl is presented. This is a benign tumor, but should be excised widely enough to include a rim of normal bone, otherwise it may recur or even undergo malignant transformation.

Adolescent↗
PubMed1980

Specific regulation by steroid hormones of protein kinases in the endometrium. 1. Alteration by estrogen and progesterone in levels of protein kinases in rabbit endometrium.

The alteration in activities of multiple protein kinases has been studied in the endometrium of a rabbit treated with estrogen and progesterone. The administration of estrogen or progesterone to the castrated rabbit resulted in a remarkable increase of total activity in the cytosol fraction of the endometrium. The administration of estrogen caused an increase of type I adenosine-3',5'-monophosphate-dependent (cAMP-dependent) protein kinase and a slight decrease of type II cAMP-dependent protein kinase. In contrast, the treatment with progesterone after priming administration of estrogen brought about an increase of type II cAMP-dependent protein kinase and a decrease of type I cAMP-dependent protein kinase. Therefore, the activity ratio of type II to type I decreased by estrogen and increased by progesterone. The simultaneous administration of cycloheximide abolished the stimulatory effect of respective hormones on the level of each protein kinase. The activity profile of protein kinases on DEAE-cellulose column after ovulation caused by the administration of human chorionic gonadotropin to a non-castrated rabbit was similar to that of the rabbit treated with progesterone. The results presented demonstrate the specific regulation by the steroid hormones of de novo synthesis of protein kinases in the target organ.

Animals↗
PubMed1980

Specific regulation by steroid hormones of protein kinases in the endometrium. 2. Alteration in levels of protein kinases in human endometrium during the menstrual cycle.

The alteration in the levels of multiple protein kinases has been studied in human endometrium during the menstrual cycle. Protein kinases were examined in the cytosol fraction and separated by DEAE-cellulose column chromatography. The level of type I adenosine 3',5'-monophosphate-dependent (cAMP-dependent) protein kinase was higher than that of type II cAMP-dependent protein kinase at the proliferative phase. At the late secretory phase, type I cAMP-dependent protein kinase markedly decreased, whereas type II cAMP-dependent protein kinase remained at the same level. Therefore, type II cAMP-dependent protein kinase was exclusively predominant at this phase. cAMP-dependent and cAMP-independent protein kinases with protamine increased more at the late secretory phase than at the proliferative phase. The results presented demonstrate a specific alteration in protein kinase activities during the menstrual cycle and are compatible with those obtained in rabbit endometrium (the preceding paper).

Adult↗
PubMed1979

Chemical reactions in cephalosporin allergy: high-pressure liquid chromatographic analysis of cephalosporin aminolysis kinetics.

Cephalosporin reaction with protein amino groups is fundamental to cephalosporin allergy. Cephalothin and cefazolin reaction kinetics with epsilon-aminocaproic acid, B-alanine, and glycine in aqueous solution were investigated. All reactions were conducted at 35 degrees and 0.5 ionic strength and were followed by ion-exchange high-pressure liquid chromatography. The aminolysis rate constants can be expressed as terms representing uncatlyzed or water-catalyzed amine reaction, self-assited nucleophilic reaction, and hydroxide-ion-catalayzed nucleophilic amine attack on the beta-lactam moiety. Cephalothin and cefazolin react with amines as readily as penicillin G. The UV spectra of several cephalothin-glycine reaction products were recorded, and their possible structures are discussed.

Amines↗
PubMed1979

GI absorption of beta-lactam antibiotics. III: Kinetic evidence for in situ absorption of ionized species of monobasic penicillins and cefazolin from the rat small intestine and structure-absorption rate relationships.

Absorption rates of monobasic beta-lactam antibiotics were measured as a function of lumen solution pH between 4 and 9 by utilizing the rat intestinal recirculating method in situ. Between pH 6.5 and 9, the absorption rate constants of ionized antibiotics were almost identical; but, at pH 4, the unionized species were highly absorbed, depending on their lipophilicity through the GI membrane lipoidal barrier. The structure-absorption rate relationship was established with the unstirred layer model.

Animals↗
PubMed1979

Carbenicillin prodrugs: stability kinetics of alpha-phenyl and alpha-indanyl esters in aqueous solution.

Both ester and beta-lactam degradations of alpha-esters of carbenicillin disodium, carbenicillin indanyl sodium, and carbenicillin phenyl sodium in aqueous solution at 35 degrees and at 0.5 ionic strength were investigated. The reactions were followed by spectrophotometric assay, reversed-phase high-pressure liquid chromatography, and colorimetric assay. The degradation pathways were established, and the rate-pH profiles for ester and beta-lactam cleavage reactions are given for pH 1-11. Below pH 3, the beta-lactam degradation of the prodrugs proceeded exclusively. Above pH 7, the degradation was superseded by the ester hydrolysis to carbenicillin, beta-Lactams of both prodrugs are around three times more stable than carbenicillin disodium at pH 1, six times at PH 2, and 17 times at pH 3. The half-lives for carbenicillin production were predicted to be 17 hr for carbenicillin indanyl sodium and 8.5 hr for carbenicillin phenyl sodium at pH 7.0 and 37 degrees.

Carbenicillin↗
PubMed1978

GI absorption of beta-lactam antibiotics I: kinetic assessment of competing absorption and degradation in GI tract.

An equation was derived for the simultaneous assessment of rate constatns for absorption and nonenzymatic degradation of unstable drugs in in situ absorption experiments. The equation was substantiated by using a variety of beta-lactam antibiotics in the recirculation technique through the rat small intestine. Plots of the apparent first-order rate constant for the disappearance of the drug from the gut lumen versus the reciprocal of the volume of recirculating solution yielded a straight line with a slope equal to the intrinsic absorption rate constant and with an intercept equal to the nonenzymatic degradation rate constant in the GI lumen. The kinetic method for evaluation of the absorption rate constant also was developed for a more complex situation in the GI lumen involving absorption, nonenzymatic degradation, and enzymatic metabolism. The proposed method was confirmed with carbenicillin indanyl, which was metabolized rapidly to carbenicillin by the action of nonspecific esterase in the intestine. In the absence of information of Michaelis--Menten kinetic parameters, the present method is advantageous for evaluation of the intrinsic absorption rate of all unstable drugs.

Animals↗
PubMed1978

GI absorption of beta-lactam antibiotics II: deviation from pH--partition hypothesis in penicillin absorption through in situ and in vitro lipoidal barriers.

The absorption of propicillin from the rat stomach and small intestine in situ was examined as a function of recirculating solution pH. The in vitro interphase transport from an aqueous buffer of various pH values to the octanol phase was also studied for several penicillins by the use of a two-phase rolling cell. The rate--pH profiles obtained from both in situ and in vitro experiments deviated significantly from the dissociation curves. The degrees of the shifts were approximately 2 pH units for the in situ intestinal absorption of propicillin and in vitro transport of propicillin and cloxacillin, approximately 1.5 pH units for the in vitro transport of penicillin V, and 0.8 pH unit for the in situ stomach absorption of propicillin. These discrepancies from the classical pH--partition hypothesis can be interpreted by the permeation through the lipoidal barrier of the undissociated species of penicillins transported through the aqueous diffusion layer adjacent to the lipoidal surface. All in situ and in vitro experiments tend to support this theory.

Animals↗