Search PubMed⌕ Search

Biomedical subjects

S Miyachi

Publications and source records attributed to S Miyachi.

At least 109 records · Page 6Linked to original sources
PubMed1981

Light-induced conversion of nicotinamide adenine dinucleotide to nicotinamide adenine dinucleotide phosphate in higher plant leaves.

Light-induced conversion of NAD to NADP was investigated in higher plants. Upon illumination, conversion of NAD to NADP was observed in intact leaves of wheat and pea following incubation in the dark. This conversion was also observed in mesophyll protoplasts of wheat leaves when they were isolated in the dark or isolated in light and then preincubated in the dark. Chloroplasts isolated from wheat protoplasts prepared in the dark carried out the conversion. The conversion in the mechanically isolated spinach chloroplasts was observed only when they were isolated in the dark from leaves preincubated in darkness.Sucrose density gradient centrifugation of wheat protoplast extracts and differential centrifugation of protoplast extracts from various plants showed that most of the NAD kinase was localized in the chloroplasts. Therefore, the conversion of NAD to NADP is considered to occur in the chloroplasts. However, with extracts of maize mesophyll protoplasts, the enzyme was localized in the extrachloroplast fraction. The NAD kinase was activated some 30% by illumination of leaves or protoplasts of pea and wheat after preincubation in the dark.These results suggest that, in general, the light-induced conversion of NAD to NADP occurs in the chloroplast and is catalyzed by photoactivated NAD kinase using photochemically produced ATP.

Journal Article↗
PubMed1981

The dynamics of clindamycin-2-phosphate in vivo and its transfer to tissues.

Studies were conducted on clindamycin-2-phosphate, a preparation of clindamycin CLDM developed for injection, and the following results were obtained. 1) The concentration of CLDM phosphate and lincomycin (LCM) in sera were measured in rabbits following continuous intravenous infusion of 20 mg/kg over a 60 minute period, and the results were compared in a crossover test. 2) The concentration of CLDM phosphate in the oral tissues of rabbits following continuous intravenous drip infusion of 20 mg/kg over a 60 minute period was found to be a maximum in the submaxillary gland (21.1 microgram/g), followed by the liver, submaxillary lymph nodes, sera and tongue. The concentration of LCM was found to be the highest in the submaxillary gland (20.2 microgram/g), followed by the submaxillary lymph nodes, tongue, sera and liver. 3) The metabolism of CLDM phosphate in vivo was investigated using TCL. CLDM phosphate was found to metabolize to CLDM N-demethyl CLDM in vivo. 4) The peak concentration of CLDM phosphate in human sera following intravenous drip infusion of 600 mg over a 60 minute period averaged 11.9 microgram/ml, while the average concentration of LCM in sera under identical circumstances was approximately twice that of CLDM phosphate.

Animals↗
PubMed1979

Comparison of the atopic background between allergic and non-allergic beekeepers.

A study was carried out on beekeepers and their families. 34 subjects with a history of bee sting allergy and also a positive radioallergosorbent test (RAST) to honey bee venom were compared with 47 subjects with neither. 16 subjects in the bee allergy group (47%) had a history of atopic diseases as compared to 6 (13%) in the control group (p less than 0.01). 15 in the bee allergy group (44%) had at least one positive RAST to three common inhalant allergens as compared to 5 (11%) in the control group (p less than 0.01). These results suggest that, although bee sting allergy frequently affects non-atopic subjects, sensitization among beekeepers and their families occurs more readily in atopics. It is notable that a large proportion of patients injected with foreign proteins (the control group) either never develop venom-specific IgE antibodies or have suppressed their production.

Adult↗
PubMed1979

Evaluation of bee sting allergy by skin tests and serum antibody assays.

We studied 55 subjects who had had anaphylactic reactions to bee stings within the previous 3 years. 38 out of 54 tested had IgE antibody to honey bee venom (HBV) as measured by radioallergosorbent test (RAST). On skin testing, 30 out of 34 had a positive test to HBV. Of these, 26 had a positive RAST. A positive skin test to HBV at high dilution or else a high anti-HBV RAST score appeared to identify those who, in a 6-month follow-up period, were at risk of developing further anaphylaxis following bee stings or immunotherapy. Of the two tests, RAST appeared to be the less sensitive. Measurements of IgG antibody to phospholipase A were seldom available for the period immediately preceding an anaphylactic episode and proved to be a poor means of predicting the liability to bee sting anaphylaxis in subsequent months.

Anaphylaxis↗
PubMed1977

Properties of a Protein Activator of NAD Kinase from Plants.

Purification of pea (Pisum sativum) seedling NAD kinase by DEAE-cellulose column chromatography resulted in loss of activity, due to dissociation of an activator from the enzyme. The purified enzyme preparation, which was almost completely inactive, regained the activity when the activator was added back.The activator was purified 320-fold by ion exchange chromatographies. The activator was susceptible to proteolytic enzymes, but not to ribonuclease, glucoamylase or pectinase, indicating that it is of a protein nature. This protein was relatively stable in boiling water, but susceptible to acid or alkali, especially under high temperatures. Restoration of catalytic activity of inactive enzyme was proportional to amounts of the activator added. Gel filtration indicated that molecular weight of the activator was 28,000.The activator was found in extracts from various plants.

Journal Article↗
PubMed1970

Effect of Oxygen on the Light-enhanced Dark Carbon Dioxide Fixation in Chlorella Cells.

With Chlorella ellipsoidea cells, the effect of oxygen was investigated on the products of enhanced dark (14)CO(2) fixation immediately following preillumination in the absence of CO(2). When the reaction mixture was made aerobic by bubbling air (CO(2)-free) throughout preillumination and the following dark (14)CO(2) fixation periods, the initial fixation product was mainly 3-phosphoglyceric acid. When nitrogen gas had been used instead of air, only about one-half of the total radioactivity in the initial fixation products was in 3-phosphoglyceric acid and the rest in aspartic, phosphoenolpyruvic, and malic acids. The percentage distribution of radioactivity incorporated in these initial products rapidly decreased during the rest of the dark period. Concurrent with the decrease in the initial (14)CO(2) fixation products, some increase was observed in the radioactivities of the sugar phosphates. The maximal radioactivity incorporated in sugar mono- and diphosphates accounted for only 10% of total (14)C, under either the aerobic or anaerobic conditions. Under anaerobic conditions most of the (14)C incorporated was eventually transferred to alanine, whereas the main end products under aerobic conditions were aspartate and glutamate. The pattern of (14)CO(2) fixation products was unaffected by the atmospheric condition during the period of preillumination. The preferential flow of the fixed carbon atom to alanine or aspartate depended on the presence or absence of oxygen during the period of dark CO(2) fixation.

Journal Article↗