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A Owaki

Publications and source records attributed to A Owaki.

6 recordsLinked to original sources
PubMed2001

The rate-determining step in P450 C21-catalyzing reactions in a membrane-reconstituted system.

Adrenal cytochrome P450 C21 in a membrane-reconstituted system catalyzed 21-hydroxylation of 17alpha-hydroxyprogesterone at a rate higher than that for progesterone in the steady state at 37 degrees C. The rate of product formation in the steady state increased with the concentration of the complex between P450 C21 and the reductase in the membranes. The complex formation was independent of the volume of the reaction, showing that the effective concentrations of the membrane proteins should be defined with the volume of the lipid phase. The rates of conversion of progesterone and 17alpha-hydroxyprogesterone to the product in a single cycle of the P450 C21 reaction were measured with a reaction rapid quenching device. The first-order rate constant for the conversion of progesterone by P450 C21 was 4.3 +/- 0.7 s(-)1, and that for 17alpha-hydroxyprogesterone was 1.8 +/- 0.5 s(-)1 at 37 degrees C. It was found from the analysis of kinetic data that the rate-determining step in 21-hydroxylation of progesterone in the steady state was the dissociation of product from P450 C21, whereas the conversion to deoxycortisol was the rate-determining step in the reaction of 17alpha-hydroxyprogesterone. The difference in the rate-determining steps in the reactions for the two substrates was clearly demonstrated in the pre-steady-state kinetics.

17-alpha-Hydroxyprogesterone↗
PubMed2001

[Differences in intake of food and nutrients between manual and desk workers].

AIM: To compare intake of food and nutrients between manual and desk workers. SUBJECTS AND METHODS: Subjects were 28,603 residents (13,432 were male and 15,171 were female) in a city. Using a questionnaire, information on frequencies of consumption of different foodstuffs for one year and the type of employment was collected. Intake of nutrients was calculated from the frequencies and compared between manual and desk workers. The comparison was carried out with stratification by gender and adjustment for age and smoking habits. RESULTS: Desk workers took larger amounts of protein and lipids, and smaller amounts of carbohydrates than manual workers. Predominant foodstuffs in the latter was rice wheat products, potatoes and soybean products, while desk workers consumed more meat, processed meat, milk products, fish, vegetables and fruits. CONCLUSIONS: Differences in intake of nutrients and food depending on occupation should be considered, when the relationship between health status and employment is evaluated.

Adult↗
PubMed1997

Validation of simplified diet history questionnaire.

Simplified methods to estimate long term nutrient intakes would be needed for not only nutritional epidemiologic studies but also other ones. Based on data of diet history questionnaires (DHQ) which ask frequency and portion size for 169 items from 2,371 participants randomly selected from our cohort study in a rural city of Japan, we simplified the DHQ by eliminating some items using stepwise regression method. To examine the validity of the simplified DHQ (SDHQ), we obtained the SDHQs from 31 volunteers who had finished to complete one-day records once a month during the previous year, we calculated Pearson's correlation coefficient and calorie-adjusted correlation coefficient between the SDHQ and twelve one-day records for each nutrient intake value. Thirty one items were selected for our SDHQ. The mean values of most nutrient intakes from the SDHQ were more than those from twelve one-day records. The correlation coefficients between the SDHQ and twelve one-day records were more than 0.30 except for fat and monounsaturated fat. Calorie adjustment increased in the correlation coefficients for some nutrients. Our results suggest that the SDHQ is a validated and easy-to-use method for assessing long term 17 selected nutrient intakes.

Adult↗
PubMed1995

[Pediatric anesthesia and stress response].

The hyperglycemic and adrenocortical responses to upper and lower abdominal surgery were studied in four groups of children. In F group, lower abdominal surgery was performed under light general anesthesia (halothane 0.3-0.5% plus nitrous oxide and oxygen) combined with intravenous injections of fentanyl 10-13 micrograms.kg-1. In L-E group, lower abdominal surgery was performed under light general anesthesia combined with lumbar epidural anesthesia (intermittent injections of 1.0% lidocaine). In T-E group, upper abdominal surgery was performed under light general anesthesia combined with thoracic epidural anesthesia (intermittent injections of 1.0% lidocaine). In H group, lower abdominal surgery was performed under general anesthesia (halothane 1.0-1.5% plus nitrous oxide and oxygen). The hyperglycemic and adrenocortical responses were inhibited in F group, suggesting that intravenous injections of fentanyl 10-13 micrograms.kg-1 prevented the endocrine-metabolic response. On the other hand, in other three groups, those responses were not inhibited. Therefore we must consider the concentration and the volume of lidocaine in epidural groups. But general anesthesia combined with epidural anesthesia had a excellent effect on the postoperative pain management.

Abdomen↗