Search PubMed⌕ Search

Biomedical subjects

T Seki

Publications and source records attributed to T Seki.

At least 577 records · Page 32Linked to original sources
PubMed1987

Cloning and nucleotide sequence of phoP, the regulatory gene for alkaline phosphatase and phosphodiesterase in Bacillus subtilis.

Two DNA fragments which complement the alkaline phosphatase-negative mutation phoP of Bacillus subtilis were cloned from a B. subtilis chromosome with the prophage vector phi CM (a derivative of phi 105). One of the fragments contained the regulatory gene phoR in addition to phoP. Nucleotide sequence analysis of the phoP region revealed that the phoP gene product consists of 241-amino-acid residues and that the sequence of these amino acids is extensively homologous with the sequence of the phoB gene product. This protein is the positive regulator for the phosphate regulon in Escherichia coli. It therefore appears that phoP is a regulatory gene for alkaline phosphatase synthesis in B. subtilis.

Alkaline Phosphatase↗
PubMed1987

Results of internal mammary artery-coronary artery bypass surgery and the characteristics of internal mammary artery grafts.

Coronary artery bypass grafting utilizing the internal mammary artery (IMA) was performed in 108 patients with an operative mortality (less than 1 month) of 0% and a hospital mortality of 1.9%. The IMA was used most often in the left anterior descending artery system in combination with saphenous vein grafts (SVG) to the right and left circumflex artery systems. Although the IMA flow was smaller than the SVG flow when measured intraoperatively by an electromagnetic flow meter, postoperative clinical, electrocardiographic, isotopic, angiographic and coronary sinus flow-metric studies all demonstrated that the IMA can respond well to myocardial blood flow demand both at rest and during exercise, resulting in excellent clinical improvements with no detectable signs of flow deficiency. In addition, no signs of ischemia were detected in any of the 15 patients with stenosis in the left main trunk treated with an IMA graft. The IMA graft appears to have a great adaptive capacity to meet increased myocardial demand. Postoperative angiography performed at an average of 3 months after surgery in 60 unselected patients demonstrated an IMA patency rate of 98% in comparison with 88% patency in SVGs to the left anterior descending artery (p less than 0.05). Not only the patency rate, but also the graft wall characteristics were much better in IMA grafts than in SVGs. Some SVGs showed marked wall irregularity as early as 3 months after surgery.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

Self-priming effect of LH-RH on pituitary gonadotropins in hyperprolactinemic women.

To investigate how various concentrations of serum prolactin (PRL) influence the priming effect of luteinizing hormone releasing hormone (LH-RH) on the pituitary gland, 24 women with various blood PRL concentrations received intravenous injections of 100 micrograms of synthetic LH-RH twice at an interval of 60 minutes and their serum LH and follicle-stimulating hormone (FSH) were measured and analysed. In the follicular phase with a normal PRL concentration (PRL less than 20 ng/ml, n = 6), marked first peaks of the two hormones following the first LH-RH stimulation and enhanced second peaks after the second LH-RH administration were observed, indicating a typical priming effect of LH-RH on gonadotropins, though the second response of FSH was more moderate than that of LH. In hyperprolactinemia, in which the serum PRL concentration was higher than 70 ng/ml (n = 13), the basal concentration of gonadotropins was not significantly changed but the priming effect of LH-RH on LH and FSH was significantly decreased (p less than 0.01). No marked second peaks of LH and FSH were observed, suggesting an inhibitory effect of hyperprolactinemia on the second release of LH and FSH. In contrast, this effect was restored in a group of women whose serum PRL concentration was between 30 and 50 ng/ml (n = 5). Furthermore, enhanced second peaks of both LH and FSH were noted after successful bromocriptine therapy reduced hyperprolactinemia (PRL greater than 70 ng/ml) to less than 25 ng/ml (n = 5).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

[One-year chronic dietary toxicity study of d.d-T80-prallethrin in rats].

d.d-T80-prallethrin, a pyrethroid insecticide for sanitary use, was administered to Crj : CD (Sprague Dawley) rats at concentrations of 120, 600 or 3,000 ppm in diet for one year to assess the chronic toxicity potential and the reversibility. The summarized results obtained are as follows: 1. Chronic toxicity study 3,000 ppm : Decreases in body weight gain, food consumption, and water intake were observed. Slight alopecia in the neck and/or back was noticed during the first and second weeks, but the animals were recovered thereafter. Slight anemic changes such as decreases in hemoglobin concentration, hematocrit value, MCV and MCH were observed in the females at 52 week. Blood biochemistry revealed increases in total cholesterol (in the males and females at 13, 26 and 52 weeks), phospholipid (in the males and females at 13, 26 and 52 weeks), albumin (in the males at 13 and 26 weeks, in the females at 52 week), total protein (in the males at 26 week, in the females at 52 week), A/G ratio (in the males at 13 week, in the females at 26 week), creatinine (in the males at 52 week), urea nitrogen (in the females at 52 week), GOT (in the males and females at 52 week) and GPT (in the males and females at 52 week), and decreases in triglyceride (in the females at 26 and 52 weeks) and alkaline phosphatase (in the males at 13 and 52 weeks). In urinalysis, an increase in bilirubin was observed in the males at 52 week. Gross-pathology revealed a lower incidence of accentuated lobular pattern of liver (in the males at 26 week) and a higher incidence of enlarged liver (in the males at 52 week). In organ weight, increases in liver (in the males and females at 26 and 52 weeks), kidney (in the males at 26 and 52 weeks) and thyroid weights (in the males at 26 and 52 weeks, in the females at 26 week), and decreases in spleen (in the females at 26 and 52 weeks) and adrenal weights (in the females at 52 week) were observed. Histopathological examination revealed a lower incidence of fatty metamorphosis in the liver of females at 52 week. 600 ppm: An increase in liver weight was observed in the males at 26 week. 120 ppm: No effect was observed. 2. Reversibility study Almost all the above chronic toxicities were reversible.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1987

[Physiological significance of the self-priming effect of LH-RH on the anterior pituitary glands].

To investigate the intracellular mechanisms of the self-priming effect of LH-RH on the anterior pituitary gland, the responses of pituitary and serum gonadotropins to two administrations of this decapeptide at a 60 min, interval were studied in male rats. A clearly recognized self-priming effect in male rats was significantly suppressed by the administration of RNA synthesis inhibitor. Although the pituitary LH content decreased significantly after the first administration, the content increased to the control level immediately before the second administration. This recovery was prevented by the administration of RNA synthesis inhibitor. In spite of the large second response, the rate of the second LH depletion was low. The number of secretory granules in gonadotrophs showed similar changes to the pituitary LH content. The dilatation of the Golgi apparatus was observable at 60 min. after the first administration. These results of rat experiments indicate that the second response includes the newly synthesized gonadotropins, and a clinical LH-RH two step test could be employed to evaluate both pituitary gonadotropin synthesizing and secreting functions.

Animals↗
PubMed1987

The characteristics of luteinizing hormone and its beta-subunit secretion in dispersed rat anterior pituitary cells.

Secretion of luteinizing hormone (LH) and its beta-subunit (LH-beta) by luteinizing hormone-releasing hormone (LH-RH) were studied in perifused rat anterior pituitary cells. LH release was dose related between 10(-10) and 10(-6)M LH-RH. Every 5-minute pulse of 10(-8)M LH-RH induced almost similar response to the initial LH release; neither the self-priming effect nor desensitization were significant. Continuous administration of 10(-8)M LH-RH caused an initial LH release, followed by distinct desensitization, which could not be overcome by subsequent pulses of 10(-8)M LH-RH. The results were quite similar in LH-beta release. The perifusion study is shown to be useful in analyzing the characteristics of LH and LH-beta release, and the present results suggest that LH-RH receptor-mediated regulation may be also involved in LH-beta release.

Animals↗
PubMed1987

Retinoid composition in the compound eyes of insects.

Retinoids in the compound eyes of insects in ten orders were extracted by the oxime method and analysed by HPLC. Four geometrical isomers (13-cis, 11-cis, 9-cis and all-trans) of syn and anti retinal oximes, and syn and anti 3-hydroxyretinal oximes were separated in a single analysis by a stepwise eluent condition. The amounts of the two isomers, syn 11-cis and syn all-trans, were quantified. 11-Cis 3-hydroxyretinal was detected in six orders: Lepidoptera, Diptera, Coleoptera, Neuroptera, Hemiptera and Odonata, and retinal and 3-hydroxyretinal were found together in the compound eyes of some species of Coleoptera and Odonata. We conclude that early in their phylogeny, insects had the ability to use 3-hydroxyretinal as the chromophore of visual pigment. Peaks corresponding to syn 9-cis and 13-cis 3-hydroxyretinal oximes were observed on the chromatogram of extracts from fly heads and compound eyes of cicadas. Retinol and 3-hydroxyretinol were also analysed and quantified relative to retinal and 3-hydroxyretinal. Larger amounts of the alcohols than the aldehydes were found in the compound eyes of butterflies, hornets, cicadas and grasshoppers, which are diurnal insects. 3-Dehydroretinal has not been detected in insects.

Animals↗
PubMed1986

Differential metabolism of fenvalerate and granuloma formation. II. Toxicological significance of a lipophilic conjugate from fenvalerate.

Male mice of the ddY strain were fed a diet containing the [2S, alpha S]-, [2S, alpha RS]-, [2R, alpha S]-, and [2R, alpha R]-isomers of fenvalerate. Microgranulomatous changes were observed only in mice treated with the [2R, alpha S]-isomer at 125 and 1000 ppm for 1, 2, or 3 months. In contrast, the changes did not occur in mice treated with the [2R, alpha R]-isomer under the same conditions. Feeding of the [2S, alpha S]- and [2S, alpha RS]-isomers for 1 year did not cause the microgranulomatous changes at 500 or 1000 ppm. To clarify the causative agent of granuloma formation, cholesterol ester of 2-(4-chlorophenyl)isovaleric acid (CPIA), a lipophilic conjugate from the [2R, alpha S]-isomer of fenvalerate, was injected iv into ddY mice. Microgranulomatous changes were observed in the liver of mice treated with the [2R]-, [2S]-, or [2RS]-CPIA-cholesterol ester 1 week after a single treatment of 1, 10, or 100 mg/kg, as well as in liver of mice treated with a single dose of 10 or 30 mg/kg of the [2R]-CPIA-cholesterol ester and kept up to 26 weeks afterward. Histochemistry and microscopic autoradiography of the liver of mice demonstrated the presence of tritium derived from 3H-labeled[2R]-2-(4-chlorophenyl)isovalerate and cholesterol. Histochemistry also was positive for cholesterol ester in livers of mice treated with the [2R, alpha S]-isomer of fenvalerate. These results lend support for the hypothesis that CPIA-cholesterol ester is the causative agent of microgranulomatous changes induced by fenvalerate.

Animals↗