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Biomedical subjects

A Kikuchi

Publications and source records attributed to A Kikuchi.

At least 415 records · Page 23Linked to original sources
PubMed1985

Enhancement of collagen-induced phosphoinositide turnover by thromboxane A2 analogue through Ca2+ mobilization in human platelets.

In human washed platelets, collagen-induced phosphoinositide turnover was inhibited by indomethacin, an inhibitor of thromboxane A2 (TXA2) formation, particularly at lower doses of collagen. This inhibition was counteracted by the addition of 9,11-epithio-11,12-methano-TXA2 (STA2), a stable analogue of TXA2 as well as by the Ca2+ ionophore A23187. STA2 and A23187 did not stimulate phosphoinositide turnover markedly, but significantly increased cytoplasmic free Ca2+ concentrations. The actions of STA2 were blocked by 13-azaprostanoic acid, a TXA2 receptor antagonist. The results suggest that TXA2 is generated during the action of collagen and increases cytoplasmic free Ca2+ which then stimulates phosphoinositide turnover in cooperation with collagen.

Blood Platelets↗
PubMed1985

An Escherichia coli mutant unable to support site-specific recombination of bacteriophage lambda.

We report the isolation of mutations in, and the characterization of, an Escherichia coli gene, hip, that is required for site-specific recombination of phage lambda. hip mutants are recessive and are located near minute 20 on the linkage map. The gene product is not vital to bacterial growth, since deletion mutants are viable. The absence of hip product reduces lambda integration to barely detectable levels and also reduces prophage excision, but less drastically. Certain mutations in the lambda int gene partially restore integration and excision in hip- hosts. Homologous recombination promoted by recA does not require hip function. In addition to their defect in site-specific recombination, hip mutants are unable to support lytic growth of phage Mu or of certain lambda mutants. Their pleiotropic phenotype closely resembles that of himA mutants, but complementation, mapping and DNA sequencing show that hip and himA are different genes.

Bacterial Proteins↗
PubMed1985

Reverse gyrase; ATP-dependent type I topoisomerase from Sulfolobus.

Reverse gyrase, a topoisomerase which introduces positive superhelical turns into DNA, has been purified from Sulfolobus to near homogeneity. It is a single polypeptide with a mol. wt. of 120 000 as determined by denaturing gel electrophoresis. Contrary to a previous report, it is a type I topoisomerase as judged by the linking-number change of closed circular DNA topoisomer. Unlike other known type I topoisomerases, ATP or dATP is required for introducing positive superhelical turns. In order to relax negatively supercoiled DNA, other nucleotide triphosphates (XTP) are also effective with low efficiency. In the absence of either XTP or divalent cations, the enzyme introduces nicks into closed circular DNA when the reaction is stopped by SDS. This suggests that reverse gyrase cuts one of the two strands of DNA in the course of its enzymatic reaction.

Journal Article↗
PubMed1985

Significance of a gastric mass screening survey.

We analyzed the rate of occurrence of gastric cancer in a population of 39,250 by mass screening survey. In 0.123% of the total subjects gastric cancer was detected, 0.064% was at early stage and 0.059% at an advanced stage. The incidence of gastric cancer in the newly examined persons was 0.17%, 0.08% was at early stage and 0.09% at advanced stage. Of the frequently examined persons 0.07% was found to have gastric cancer, 0.043% at early stage and 0.027% at an advanced stage. The rate of occurrence of early gastric cancer was significantly higher than that of advanced gastric cancer within a 1 1/2 year interval of screening. From these results, gastric mass screening survey is considered to be effective in detecting asymptomatic gastric cancer in the "newly examined persons," and also to be beneficial in detecting "early" gastric cancer at intervals of 1 1/2 years of screening.

Adult↗
PubMed1984

[Radiotherapy for esophageal carcinoma with broncho-esophageal fistula].

We studied treatment methods after fistula formation in 14 esophageal carcinoma patients with broncho-esophageal fistulae. Among 12 patients, 8 had no treatment, one was operated and 3 underwent radiotherapy using conventional fractionation. In only one case was there temporary closure of the fistula; none of the patients survived for more than 1 year. The other 2 patients were treated by the long protracted method (1.5 Gy/day). Long-term closure of the fistula was seen. These patients received additional low-dose rate teletherapy (1 Gy/hour, 7 Gy/day) and both survived for over 1 year.

Aged↗
PubMed1983

Genetic determinant of pyocin R2 in Pseudomonas aeruginosa PAO. II. Physical characterization of pyocin R2 genes using R-prime plasmids constructed from R68.45.

The chromosome segment which contains the genes responsible for production of pyocin R2 in P. aeruginosa PAO was defined physically using R-prime plasmids constructed in vivo from R68.45. The previous conclusion from genetic mapping that the cluster of pyocin R2 genes is located in between trpC and trpE genes was confirmed by deletion mapping of various R prime plasmids bearing the trpC gene. The pyocin R2 gene cluster was further localized on two contiguous HindIII fragments of 16 kb and 8.0 kb. PML14 strain, in which R-type pyocin genes were completely deleted, had only one 11 kb HindIII fragment instead. Heteroduplexes between this 11 kb fragment with the two HindIII fragments of PAO revealed that the cluster of pyocin R2 genes was an insertion 13 kb long.

Bacteriocins↗
PubMed1982

The effects of postoperative radiotherapy in cases of invasive carcinoma of the uterine cervix.

An investigation was made of the effects on cure rate of postoperative radiotherapy following radical hysterectomy with lymphadenectomy for cases of invasive carcinoma of the uterine cervix performed over 7 years between 1969 and 1975 at the Department of Obstetrics and Gynecology. Tohoku University Hospital. For cases in which resection was complete but the cancer extended to the pelvic wall, the 5 year survival rate was similar to that in comparable cases of the same clinical stage regardless of whether or not postoperative radiotherapy was employed. The 5 year survival rate in cases undergoing postoperative radiotherapy because of lymph node metastasis was lower than that of cases where the lesion approached the pelvic wall and for which postoperative radiotherapy was employed. An investigation of the 5 year survival rate among those cases with lymph node metastasis and receiving postoperative radiotherapy indicated that survival in cases with metastasis to only one lymph node was similar to that of cases of the same clinical stage which received the operation only, whereas the survival rate of cases with multiple lymph node involvement was markedly lower.

Adenocarcinoma↗