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Biomedical subjects

Y Chiba

Publications and source records attributed to Y Chiba.

At least 289 records · Page 16Linked to original sources
PubMed1987

Effect of breast feeding on responses of systemic interferon and virus-specific lymphocyte transformation in infants with respiratory syncytial virus infection.

In order to elucidate the mechanisms of breast-feeding-induced resistance to respiratory syncytial virus (RSV) infection, groups of breast-fed and bottle-fed infants with this infection were tested at the onset of illness and then again 1 and 2 weeks later for the presence of interferon (IFN) as well as of virus-specific lymphocyte transformation (LTF) activity. Alpha-IFN was detected in nine out of ten breast-fed infants, while it was found in only 11 out of 21 bottle-fed subjects. The rate of the detection of IFN was significantly higher in the former group (P less than .05). Mean levels of IFN activity were also higher in breast-fed infants than in bottle-fed subjects during the course of the illness. It was noted, however, that previous breast feeding elicited little enhancing effect on the IFN response of infants with RSV infection. Combining the two feeding groups, suppressed LTF activity to RSV seemed to be related to a positive IFN response, although the association was not statistically significant. These observations suggest that breast feeding has unique mechanisms for modulating the immune response of infants with RSV infection.

Breast Feeding↗
PubMed1987

Cerebral gangliocytoma. An ultrastructural study.

We report a case of cerebral gangliocytoma (GC) with a variety of unusual structures in the tumor cells. Light microscopically, the tumor consisted of typical ganglion cells, atypical cells which has argyrophilic granules in the cytoplasm, and a few astrocytes. Electron microscopically, the tumor cells showed typical gangliocytic features, which had abundant rough endoplasmic reticula, ribosomes and cored vesicles of 90-150 nm diameter, a few 50-nm-diametered non-cored vesicles, and other common organelles in their cytoplasm. Furthermore, neoplastic ganglion cells contained a variety of abnormal structures, including membranous cytoplasmic bodies (MCB), Zebra bodies (ZB), tubular structures, branched tubular structures (BTS), concentrical laminated bodies and curvilinear bodies (CB). The MCB, ZB and CB resembled those in GM2 gangliosidosis (GMG), and the BTS that in infantile neuroaxonal dystrophy (INAD). Although the significance of these inclusions is still unknown, it is considered that some common mechanism might play a role in the metabolism of both neoplastic neuronal cells and degenerating neurons (GMG and INAD). Synapses could not be observed anywhere despite complete neuronal differentiation of many tumor cells.

Adult↗
PubMed1987

Antigenic characterization of rotaviruses isolated in Kenya from 1982 to 1983.

The electropherotypes of human rotavirus RNAs from 100 diarrheic stool specimens collected in two major districts of Kenya from 1982 to 1983 were previously reported (Y. Chiba, C. Miyazaki, Y. Makino, L. N. Mutanda, A. Kibue, E. O. Lichenga, and P. M. Tukei, J. Clin. Microbiol. 19:579-582, 1984). Of these specimens, 25 that contained rotaviruses with different RNA electropherotypes were subjected to a virus isolation experiment with MA-104 cells, and 16 rotavirus strains were isolated. The use of an enzyme-linked immunosorbent assay with subgroup-specific monoclonal antibodies enabled us to successfully subgroup 15 isolates: 4 in subgroup I and 11 in subgroup II. By fluorescent-focus-neutralization test with serotype-specific rabbit antisera, 13 isolates could be serotyped: 7 as serotype 1, 4 as serotype 2, and 2 as serotype 3. Of the remaining three isolates, F153, F247, and G402, the former was doubly neutralizable with serotype 1 and serotype 4 antisera and the latter two were neutralizable with serotype 3 and serotype 4 antisera. Detailed analysis with the antisera against F153 and F247 and four serotype-specific, VP7-directed monoclonal antibodies suggested that F153 is a serotypic mosaic strain with serotype 4-specific VP3 and serotype 1-specific VP7 outer capsid proteins and F247 and G402 are possibly antigenic mosaic strains with serotype 3 and serotype 4 antigens. On the basis of the correspondence of the rotavirus isolate serotypes determined in this study to the electropherotypes reported previously, it was inferred that serotype 1 strains were most prevalent in two districts of Kenya from 1982 to 1983, followed by any type of serotypic mosaic strains.

Antibodies, Monoclonal↗
PubMed1987

Hormone release from pancreatic islets perfused from venous side.

Directional blood flow in pancreatic islets may be important for regulation of islet hormone release. We therefore perfused an isolated canine pancreas via the celiac artery (arterial perfusion) and then via the portal vein (venous perfusion) in the same pancreas. Basal insulin and glucagon levels and their rate of release in response to 10 mM arginine, 11 mM glucose, 500 pg/ml somatostatin, or 500 pg/ml glucagon were similar under both conditions. However, the inhibition of glucagon release due to somatostatin and its recovery after the cessation of somatostatin infusion was poor in the case of venous perfusion. The basal somatostatin level and its release in response to 10 mM arginine, 11 mM glucose, and 500 pg/ml glucagon during venous perfusion was significantly higher than that during arterial perfusion. From these results, it is speculated that the directional blood flow in pancreatic islets may not be essential for regulation of hormone release from the canine pancreas or that such directionality does not exist in canine pancreatic islets, and that a considerable portion of released somatostatin may be taken up by the pancreas located downstream--probably in the exocrine pancreas.

Animals↗
PubMed1987

Effect of the intermittent prophylactic treatment of the central nervous system in adults with acute leukemia.

Nineteen patients with acute leukemia, who achieved complete remission between January, 1980 and March, 1983, were given 10 mg of methotrexate (MTX) and 20 mg of prednisolone (PSL) intrathecally at 1st, 3rd, 6th, 10th and 15th month after the termination of consolidation therapy followed by the same dose twice a year, when the intensification therapy was being performed. During the observation period of 29 to 68 months, none developed central nervous system (CNS) leukemia. On the other hand, the incidence of CNS leukemia in patients given the prophylactic intrathecal treatment once or twice just after the complete remission was 35% (7/20) compared with 24% (8/33) in patients without treatment. No statistical difference was observed in these groups. The intrathecal administration of MTX and PSL is easy to perform and no adverse reaction was observed in our series. It is concluded that the intermittent prophylaxis with MTX and PSL is of benefit in preventing CNS leukemia in adults patients with acute leukemia.

Acute Disease↗
PubMed1987

[Successful management of abdominal aortic aneurysm due to bacterial infection: report of a case].

A successful surgery of abdominal aortic aneurysm due to bacterial infection is described. The patient, 71-year-old man, had been suffering from high fever of unknown origin which had narrow escape with the several kinds of antibiotics about a month and more. During the antibiotic therapy in another hospital, he was diagnosed as an abdominal aortic aneurysm by whole body computed tomography. Immediately after the arrival to our hospital, digital subtraction angiography was done, and it showed a saccular aneurysm in the infrarenal abdominal aorta. Surgical removal of this aneurysm without opening of the aneurysmal wall was performed and the kitted dacron graft was used for aorto-biiliac anastomosis. The diagnosis of aneurysm due to bacterial infection was confirmed by bacteriological and pathological examinations. The patient in now surviving 17 months after operation. Abdominal aortic aneurysm due to bacterial infection is a serious disorder that generally carries grave prognosis. Complete removal of infected lesion without contamination and long-term follow-up with antibiotic chemotherapy are essential for this disease.

Acinetobacter Infections↗
PubMed1986

Predominance of nasal over temporal saccades in fast eye movement.

Quantitative analysis of saccadic eye movement caused by 20 degree amplitude gaze in horizontal plane was undertaken in 131 subjects using the Contraves' computerized oculomotor testing system. All of the subjects were free from any spontaneous nystagmus, neurological symptoms, and abnormalities of vestibular function. Both of the monocular recordings of saccade were made with a 3 sec time constant, 25 Hz high-cut filter, and digitized with a 3.9 msec sampling time. Four parameters i.e., maximum velocity, gain, latency, and duration, were analyzed. The average (S.D.) of each parameter was 337.1 (65.7) degree/sec, 1.00 (0.14), 199.1 (44.0) msec, and 128.3 (20.2) msec, respectively. We discussed the differences between nasal saccade and temporal saccade. The former was faster than the latter in maximum velocity and shorter in duration, while no differences were recognized in latency. It is suggested that the predominance of nasal saccade in fast eye movement is due to the anatomical difference of the vestibulo-ocular pathway between the medial rectus and the lateral rectus. In other words, because the synaptic inputs to the medial rectus are excitatory as opposed to the inhibitory and excitatory the inputs to the lateral rectus, the difference in muscle tone between the two muscles results in a faster maximum velocity of nasal saccades in fast eye movement.

Adult↗
PubMed1986

Effects of parenteral palatinose on glucose metabolism in normal and streptozotocin diabetic rats.

The present experiment was carried out to investigate the metabolism of palatinose (6-O-alpha-D-glucopyranosyl-D-fructose) in the rat. The bolus injection of palatinose (0.5 g/kg) in the tail vein of normal and streptozotocin (STZ) diabetic rats caused significant increments in glucose and insulin concentrations. However, in severe STZ diabetic rats (greater than 300 mg/dl of fasting plasma glucose) no significant change in glucose and insulin concentrations was observed. In liver perfusion, the gradual decrease in glucose output from the normal and mild STZ diabetic rat livers perfused with 20 mM Krebs-Ringer-Tris buffer pH 7.4 was prevented by the addition of 5.5 mM palatinose in the perfusate and fructose was detected in the effluent during the palatinose infusion. The results indicate that palatinose is metabolized to glucose and fructose in both normal and diabetic rat tissues, and this causes the increase in blood glucose concentration. On the other hand, the direct stimulatory effect of insulin release from pancreatic B-cell was not observed when the palatinose was infused into the isolated perfused rat pancreas. The study suggest that palatinose administered parenterally is metabolized by tissues and expected to be used as a source of fluid and energy supply.

Animals↗
PubMed1986

Enhancement of antitumor activity of 5-fluorouracil by ribothymidine.

The antitumor activity of 5-fluorouracil (5-FU) in combination with ribothymidine was examined on some experimental murine carcinomas. The antitumor activity of 5-FU against Ehrlich ascites carcinoma was markedly enhanced by intraperitoneal coadministration of ribothymidine. The enhancement of the antitumor activity of 5-FU by ribothymidine was also observed against Ehrlich solid carcinoma both by oral and intraperitoneal administrations. Furthermore, the combination therapy of 5-FU and ribothymidine was effective even on 5-FU-resistant P388 leukemia. These results suggest that the combination of 5-FU and ribothymidine may be more effective than 5-FU monotherapy in clinical use.

Animals↗
PubMed1986

Mechanisms of potentiation of antitumor activity of 5-fluorouracil by ribothymidine in a mouse tumor system.

In the presence of ribothymidine, the uptake of 5-fluorouracil (5-FU) was enhanced in Ehrlich ascites carcinoma cells in vitro, and was efficiently converted to FU-nucleotides. In these cells, almost all ribothymidine was found to be converted to thymine by, presumably, uridine phosphorylase. The enhanced uptake of 5-FU and its efficient conversion to FU-nucleotides were also observed in Ehrlich ascites carcinoma of ribothymidine-coadministered mice. The radioactivity of 5-FU-14C in the carcinoma cells, which was detected mainly in the acid-soluble fraction immediately after the administration and then shifted to the ribonucleic acid fraction, was approximately 2-fold higher in the ribothymidine-coadministered group than in the control group. On the other hand, ribothymidine-14C was also taken up by the carcinoma cells and an appreciable portion of its radioactivity appeared in the thymine fraction. Thymine produced from ribothymidine-14C was also detected in the extracellular ascitic fluid. The conversion of ribothymidine to thymine was assumed to be catalyzed by uridine phosphorylase, suggesting that ribose 1-phosphate was coproduced and served as a ribose donor for 5-FU. These results suggest that ribothymidine may act as a ribose donor for 5-FU to form FU-nucleotides via 5-fluorouridine in carcinoma cells, resulting in the potentiation of 5-FU activity.

Animals↗