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Biomedical subjects

T Iwata

Publications and source records attributed to T Iwata.

At least 325 records · Page 18Linked to original sources
PubMed1987

[The criteria of radiotherapy for treating carcinoma of the esophagus].

The criteria of radiation therapy is given for the treatment of a carcinoma of the esophagus, said criteria decided by a committee of the Japanese Association for Radiotherapy Systems at the request of the Japan Radiological Society. The indication for radiation therapy is described and adapted to the new TNM Classification, based on the depth of the invasion of the tumor. The depth of the tumor invasion is divided into 4 stages and the radiological images for each are shown. To evaluate the effect of radiotherapy, cases are divided into curable and non-curable groups, according to the degree of changes of the radiological findings after irradiation, and each group is further subdivided into absolute and relative categories.

Esophageal Neoplasms↗
PubMed1986

Effects of 5-fluorouracil on globin mRNA synthesis in murine erythroleukemia cells.

Although 5-fluorouracil (FUra) incorporates in all species of RNA, the molecular basis for producing cytotoxicity by RNA-related mechanisms remains unclear. We have studied the effects of FUra on the synthesis of alpha- and beta-globin mRNA in murine erythroleukemia cells. An analysis of equivalent amounts of RNA from FUra-treated cells suggested that this agent causes a relative increase in globin mRNA. However, when RNA obtained from the same number of cells was analyzed, thus taking into account decreases in ribosomal RNA, the amount of intracellular alpha- or beta-globin mRNA actually decreased following FUra treatment. The decrease in globin mRNA was associated with decreases in both intracellular globin and hemoglobin content. The findings thus indicate that FUra inhibits the accumulation of alpha- and beta-globin transcripts. This effect of FUra could occur by decreasing transcriptional rate or, as in the case of ribosomal RNA, by interfering with the processing of these nucleic acids. Either mechanism could contribute to the RNA-related cytotoxicity induced by this agent.

Animals↗
PubMed1986

Immunological characterization of sn-1,2-diacylglycerol and sn-2-monoacylglycerol kinase from pig brain.

Rabbit antisera were raised against diacylglycerol kinase purified from pig brain cytosol. Upon immunoblot analysis, the antibody was specifically reactive with the kinase (Mr = 79,000-80,000). Pig brain cytosol, microsomal, and synaptosomal fractions all contained the immunoreactive Mr = 80,000 polypeptide, thus showing that the same enzyme is present in the soluble as well as membrane fractions of the brain. The antibody could precipitate only 60% of the kinase activity present in the crude cytosol. Further, the antibody exhibited very little or no cross-reactivity toward liver cytosolic enzymes obtained from different animals including pigs. Immunostaining of brain tissues demonstrated that neurons, in particular, their nuclei, were positively stained, whereas glial cells were not stained. It is likely that there exists a tissue-and/or cell-dependent immunological multiplicity of diacylglycerol kinase. The enzyme activities phosphorylating sn-1 and sn-2 monoacylglycerols were co-precipitated by the antibody, indicating their identity with diacylglycerol kinase. The enzyme activity toward sn-1 monoolein was much lower than that obtained with sn-2 monoolein. Enzymic as well as chemical analyses of acyl isomers of the reaction products showed that even tested with pure (greater than 95%) sn-1 monoolein, about 70% of the formed lysophosphatidate was of the sn-2 acyl type. The results show that diacylglycerol kinase phosphorylates almost exclusively the sn-2 acyl type of monoacyl-glycerol.

Animals↗
PubMed1986

Effects of ornithine decarboxylase inhibition on c-myc expression during murine erythroleukemia cell proliferation and differentiation.

The polyamines putrescine, spermidine, and spermine have been implicated in the regulation of cellular proliferation and differentiation. We have previously demonstrated that spermidine is required for proliferation of murine Friend erythroleukemia (MEL) cells. We have also shown that spermidine is required at a transcriptional level for induction of MEL globin synthesis. Since studies monitoring c-myc expression have suggested that this gene also plays a role in both growth and differentiation, we have monitored the effects of inhibiting ornithine decarboxylase (ODCase) activity and polyamine synthesis on levels of c-myc transcripts. The results demonstrate that the level of c-myc RNA is independent of ODCase inhibition and depletion of intracellular spermidine. More importantly, arrest of MEL proliferation is not associated with detectable changes in c-myc expression, while under these conditions there is a decline in ODCase transcripts. During induction of MEL differentiation with dimethyl sulfoxide (DMSO) and hexamethylene bisacetamide (HMBA), c-myc and ODCase undergo similar changes in patterns of expression. However, although spermidine is required for appearance of the differentiated MEL phenotype, depletion of this polyamine by ODCase inhibition had no detectable effect on the biphasic changes in c-myc RNA observed during MEL differentiation. Thus, these biphasic changes in c-myc expression are not sufficient for induction of the mature phenotype. Finally, these results would indicate that the regulation of c-myc expression during both proliferation and differentiation is independent of ODCase activity and inhibition of proliferation by spermidine depletion.

Acetamides↗
PubMed1986

Plasma half-life and organ uptake ratio of radiolabeled glandular kallikrein in control and nephrectomized rats.

The purified rat urinary kallikrein was radiolabeled by lactoperoxidase method and by chloramine T method. Plasma half-life of radiolabeled kallikrein was 5.06 +/- 0.59 (n = 5) min in control rats and 5.24 +/- 0.42 (n = 5) min in nephrectomized rats. There was no difference between two groups. From autoradiogram, main metabolic organs of radiolabeled kallikrein were liver, kidney and spleen. Total uptake of radiolabeled kallikrein in ech organ was the highest in liver (73.2%). The uptake per g tissue of radiolabeled kallikrein in each organ was high in liver (33.0%), kidney (31.4%) and spleen (21.1%). These results suggest that the active kallikrein is metabolized mainly in the liver, and kidney is not so an important organ to metabolize or to eliminate the active kallikrein in plasma. In order to clarify the mode of existence of active kallikrein in plasma, the following experiment was done by using disc gel electrophoresis. Radioactive profile of radiolabeled kallikrein showed one peak (Rf = 1.0), but radiolabeled kallikrein mixed with rat plasma showed two peaks, that is small peak (Rf = 1.0), and main peak (RF = 0.5). The most of radiolabeled kallikrein was bound to plasma protein and only five per cent was in free form. Furthermore, the binding of radiolabeled kallikrein to plasma protein was interfered by the addition of active kallikrein. These results suggest the possibility of existence of kallikrein binding protein in plasma.

Animals↗
PubMed1986

Adverse reactions and antibody responses to acellular pertussis vaccine.

Two types of acellular pertussis vaccine are used in Japan: the filamentous hemagglutinin (F-HA) predominant type and the pertussis toxin (PT)-F-HA type. We tested one lot of vaccine from each of three manufacturers (lots A and B, F-HA predominant type; lot C, PT-F-HA type). One hundred fifteen healthy children between the ages of 3 months and 23 months were immunized with one of the three lots of acellular pertussis vaccine to assess adverse reactions and antibody responses. The incidence of fever (temperature greater than or equal to 38 degrees C) was 2.6% for lot A, 1.2% for lot B, and 2.5% for lot C. The incidence of local reactions greater than 5 cm in diameter was 1.9% for lot A, 2.4% for lot B, and 3.3% for lot C. Thus no significant differences in adverse reaction were observed. The anti-PT antibody responses in the tested vaccines were equal to or greater than those in patients with pertussis in the convalescent stage, and the anti-F-HA antibody responses were far higher than those of convalescing patients. Lot C produced the highest anti-PT antibody, and Lot A the highest anti-F-HA antibody.

Agglutinins↗
PubMed1986

Comparison of blood-free medium (cyclodextrin solid medium) with Bordet-Gengou medium for clinical isolation of Bordetella pertussis.

Cyclodextrin solid medium (CSM) developed by us was evaluated to be a suitable synthetic medium for the clinical isolation of Bordetella pertussis when compared with Bordet-Gengou (BG) medium. The addition of 5 micrograms of cephalexin (CEX) per ml to CSM not only supported the good growth of B. pertussis but also sufficiently suppressed the growth of nasopharyngeal flora. During period 1 of this study, nasopharyngeal specimens from 60 patients with clinical pertussis were inoculated on CSM supplemented with 5 micrograms of CEX per ml. The isolation rate was 70% (42 of 60). To confirm the efficacy of CSM, another study was performed. During period 2 of this study, nasopharyngeal specimens were cultured on both CSM and BG medium, each with 5 micrograms of CEX per ml. The comparative isolation rates were 100% (40 of 40 specimens from 29 patients) on CSM with 5 micrograms of CEX and 65% (26 out of 40) on BG medium with 5 micrograms of CEX. The excellent efficacy of CSM as measured by the isolation rate was thought to be due to the poor nutrition of this medium for the growth of nasopharyngeal bacteria. CSM retained its efficacy in clinical isolations even after 3 months of storage in a refrigerator. These data led us to conclude that CSM with 5 micrograms of CEX was much better than BG medium with 5 micrograms of CEX, determined by both the isolation rate and preservativity considerations, and that CSM with 5 micrograms of CEX per ml can be successfully used instead of BG medium as a medium for the clinical isolation of B. pertussis.

Bordetella pertussis↗
PubMed1986

Plasma norepinephrine in sleep apnea syndrome.

In 8 male patients suffering from sleep apnea syndrome, plasma norepinephrine (NE) levels were examined. At 22.00 and at 6.30 blood samples were obtained. In 3 cases, plasma NE levels displayed little changes between 22.00 and 6.30. In 2 cases, plasma NE levels at 6.30 increased 20% compared with those at 22.00. In 3 cases, plasma NE levels at 6.30 increased more than 40%. No significant correlation between apnea index and plasma NE levels was observed. Total time under 90% arterial oxygen saturation (SaO2) significantly correlated with the ratio of plasma NE levels at 6.30 to those at 22.00. In 2 cases of the 8 patients blood samples were drawn hourly (22.00-6.00) and at 6.30. In these 2 cases, when SaO2 decreased, plasma NE levels tended to increase. It is concluded that in sleep apnea syndrome plasma NE levels increased during sleep and did not correlate with apnea index but with oxygen desaturation.

Adult↗