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S Shigeta

Publications and source records attributed to S Shigeta.

At least 271 records · Page 15Linked to original sources
PubMed1986

Immunological effects of arsenic compounds on mouse spleen cells in vitro.

Immunological effects of arsenic compounds on mouse spleen cells in vitro were examined. Three kinds of arsenic compounds: sodium arsenite, sodium arsenate and dimethyl arsenic acid, at high doses, suppressed the plaque-forming cell response to sheep erythrocytes and the proliferative response to mitogens, whereas at low doses they enhanced both responses. And each of arsenic compounds differs in strengths at which the modulation effects on both responses were exerted. The strength was comparable to general toxicity of arsenic compounds.

Animals↗
PubMed1985

Weight reduction of thymus and depletion of lymphocytes of T-dependent areas in peripheral lymphoid tissues of mice infected with Francisella tularensis.

When BALB/c mice (young and adult animals of both sexes) were infected intraperitoneally with 10(3) viable cells of Francisella tularensis (10(2) 50% lethal dose), all mice in these groups died on day 4. Reductions in thymus weights and in numbers of thymic cortex lymphocytes were observed in all the groups, but the decline was not so severe in the young females. Increases of plasma corticosterone in the adult males began 1 day after infection, but in the young females, the levels did not increase until day 3, the same days on which the respective thymus weights began to decline. Depletion of the thymus weights in the infected mice was prevented by adrenalectomy. The lymphocytes of the thymus (T)-dependent areas in peripheral lymphoid tissues in all groups were destroyed. By using an electron microscope, we found a large quantity of F. tularensis within the macrophages in the T-dependent areas but not in the thymus. The destruction of lymphocytes in the T-dependent areas was not prevented by adrenalectomy. Therefore, it was concluded that the weight reduction of the thymus is due to the stress of the F. tularensis infection. However, we think other mechanisms are responsible for the depression of lymphocytes in the T-dependent areas of peripheral lymphoid tissues.

Adrenalectomy↗
PubMed1985

[Development and evaluation of the ambulatory relative metabolic rate (RMR) realtime monitoring system].

Development of an ambulatory RMR monitoring system for evaluating the physical work-load is presented. This system can be used under special conditions where it is difficult to use the traditional "Douglas" method. The main features of this system are: Using an improved turbin-spirometer to measure expiratory gas volume, data-processing procedure is simplified by converting a 0.1 iota expiratory gas volume to an electric pulse signal. Utilizing a Galvanic-cell type sensor, a kind of porlarograph electrode, to measure oxygen concentration in expiratory gas, the temperature of the electrode is maintained constantly at 40 degrees C in order to stabilize the output of the sensor against change in environmental and expiratory gas temperature. To improve the accuracy measurement of oxygen concentration and to prevent the teflon membrane at the top of the electrode from chilling and vibrating by direct expiratory gas flow, the bypass stream line is led to the electrode and a small portion of expiratory gas is introduced to measure oxygen concentration. It is possible to measure the time-sequential RMR value for several hours by minimizing and lightening the measuring instruments. It is possible to measure the time-sequential changing characteristics of the physical work-load (RMR), heart rate, breathing rate, and skin temperature under the actual work environment by a telemetring or portable recording method.

Energy Metabolism↗
PubMed1985

[Comparative studies of antimicrobial agents against causative organisms isolated from urinary tract infections (1983). III. Secular changes in susceptibility].

The in vitro antimicrobial activities of antibiotics against causative pathogens isolated from patients with urinary tract infections (UTI) in the 8 institutions in Japan during the period from 1980 to 1983 were compared. A number of new beta-lactam antibiotics with broad spectrum of activity have become available for clinical use in recent years. Some of them, in particular so-called third generation cephems, are reported to be responsible for developing microbial-cross resistance to multiple beta-lactam antibiotics. We have been making survey in recent years to explore changes in susceptibility to various antimicrobial agents of clinical isolates. All bacterial isolates from clinical specimens were submitted to the Department of Clinical Pathology, Juntendo University School of Medicine, where they were tested for antimicrobial susceptibility with MIC 2000 apparatus. Of all pathogens from patients with simple UTI, the majority of the isolates was E. coli and Klebsiella spp. In cases of complicated UTI, on the other hand, Pseudomonas spp. were most frequent, followed in order by Proteus spp., Klebsiella spp., Serratia spp., Citrobacter spp. and E. coli. Conspicuous changes in antimicrobial activity of antibiotics against E. coli and Klebsiella spp. from simple UTI have not been found in our survey. Against strains of Citrobacter spp., even the third generation cephems proved to be not remarkably active and there was a significant decrease in susceptibility of isolates to the drugs test-showed MIC values of 50 micrograms/ml and the proportion increased to 50% (22/44) with isolates obtained in 1982. The antimicrobial activity of cefsulodin and gentamicin against P. aeruginosa was decreased in 1982 compared with that in 1980 and 1981. However, resistant strains were slightly more frequent with gentamicin. In 1983, the antimicrobial activity of third generation cephems against Serratia spp. was significantly reduced from that in 1982.

Anti-Bacterial Agents↗
PubMed1985

[Comparative studies of antimicrobial agents against causative organisms isolated from urinary tract infections (1983). I. Susceptibility distribution].

During 1979-1983 in vitro activities of antimicrobial agents against causative bacteria isolated from patients with urinary tract infections (UTI) were investigated by Microbiological Research Group of UTI including the 8 institutions in Japan. Of all strains (219) isolated from patients with simple UTI, 65.3% were E. coli, and 9.6% Klebsiella spp.; these species accounted for about 75% of all isolates in 1983. MPC and CCL among the oral antimicrobial agents have showed potent activities against E. coli, MPC at 1.56 micrograms/ml and CCL at 3.13 micrograms/ml inhibited 80% of E. coli from simple and complicated UTI. CTM, CTX, CZX, CMX and LMOX among the parenteral antimicrobial agents, at concentrations of 0.20 micrograms/ml or less inhibited 90% of E. coli isolated from simple and complicated UTI. The frequency of isolates from patients with complicated UTI, without catheter, was as follows; E. coli 27.6%, P. aeruginosa 20.1%, Streptococcus spp. 12.6%, Serratia spp. 8.8% and Klebsiella spp. 8.0%. The frequency of isolates from patients with complicated UTI, indwelling catheter, was as follows; P. aeruginosa 22.6%, Streptococcus spp. 18.0%, Serratia spp. 15.0%, Proteus spp. 12.4%, and Enterobacter spp. and Klebsiella spp. are 6.0%, respectively, in 1983. The antibacterial activity (MIC80) against E. coli, Klebsiella spp., P. mirabilis, Citrobacter spp. and Serratia marcescens from simple and complicated UTI was compared, for example, among third generation cephem antibiotics. Four drugs such as CMX, CZX, CTX and LMOX showed virtually comparable activities while CPZ was slightly less active against the strains tested. There have been many studies reported concerning the antibacterial activity of various drugs against clinical isolates from patients with infections, but it seems that, to our knowledge, no article has dealt with yearly surveys on antimicrobial susceptibility of bacterial isolates from defined clinical specimens with the same period of each year at the same series of institutions.

Anti-Bacterial Agents↗
PubMed1985

[Comparative studies of antimicrobial agents against causative organisms isolated from urinary tract infections (1983). II. Background of patients].

We have been collected the causative isolates from patients with urinary tract infections (UTI) from the 8 institutions in Japan during 1980-1983. All strains isolated from UTI and recognized as etiologically responsible in each institution were sent to Bacteriology Laboratory of Juntendo University Hospital, Tokyo and the species of these strains were reidentified. We classified the UTI into 3 categories, simple, complicated without catheter and complicated with catheter. Of all strains isolated as etiologically responsible from cases of simple UTI, 65.3% were E. coli and 9.6%, Klebsiella spp. in 1983: these species accounted for about 75% of all isolates. Most frequently isolated from patients without catheter were E. coli 27.6% in 1983, followed in order by Pseudomonas spp. (20.9%), Gram-positive bacteria (16.7%), Serratia spp. (8.8%), Klebsiella spp. (8.0%) and Proteus spp. (7.1%). In complicated UTI with catheter, Pseudomonas spp. were most frequently isolated (25.6%), followed in order by Gram-positive bacteria (22.9%), Serratia spp. (15.0%), Proteus spp. (12.4%), Enterobacter spp. (6.0%) and Klebsiella spp. (6.0%). A remarkable difference, that is, Gram-positive bacteria, especially S. aureus, showed conspicuous increase of isolation between 1982 and 1983. Furthermore, we discussed the detailed analysis of patient background to clinical bacterial isolates from UTI in respect of patient distribution by sex, types of infections, distributions by age in male and female, interrelations between the species of bacterial isolates and types of infection and antimicrobial chemotherapy.

Administration, Oral↗
PubMed1984

Isolation and characterization of an asthma-inducing sea-squirt antigen.

An antigen capable of inducing asthmatic attack in patients with sea-squirt allergy has been isolated from body fluid of sea-squirt, Styela plicata, and designated as DIIIa. The chemical composition and the behavior in anion-exchange chromatography showed that the antigen was a weakly acidic glycoprotein. The weight-average molecular weight of DIIIa was estimated to be 9,880 by the sedimentation equilibrium method. This antigen was apparently discriminated from the previously isolated sea-squirt antigens, Gi-rep and Ei-M, by its activity to induce asthmatic attack and conjunctival congestion, though it gave a strongly positive reaction in skin tests against allergic patients, similarly to the previous antigens. From the cross-reaction of DIIIa to rabbit anti-Gi-rep and anti-Ei-M sera in vitro, it was confirmed that the antigen carried essentially the same antigenic determinant as Gi-rep and Ei-M, and this was termed type alpha determinant. Furthermore, the allergenic activities detectable in vivo and the reactivity to the rabbit antisera in vitro were simultaneously absorbed by immobilized immunoglobulin from anti-Gi-rep serum. Thus, it was suggested that the antigenic determinant responsible for the allergic reactions in vivo corresponded to that specified as type alpha in vitro on the basis of the reactivity against the rabbit anti-Gi-rep serum.

Amino Acids↗
PubMed1984

[An experimental study on the duration of a single spell of work on VDT (visual display terminal) performance].

The relation between work load and the duration of a single spell of work on VDT performance studied in an experimental word processing task. Nine healthy male college students performed 2-hour visual tasks under the following three sets of work conditions. In the first set, subjects performed VDT work for two hours without intermission. In the second set, subjects had a 10-minute intermission after a 1-hour task. In the third set, there was a 5-minute intermission after a 30-minute task. Critical flicker fusion, near point distance, subjective fatigue symptoms, heart rate, respiratory rate, blinking counts, electromyogram in upper limb and performance score were measured. Results are as follows. Decrease in critical flicker fusion, increase in near point distance and subjective fatigue symptoms appeared in all three sets of experimental conditions after two hour tasks. Increased slow wave components on electromyogram and increased errors in performance appeared after 60-minute or more tasks without intermission. Effects on the critical flicker fusion, near point distance, subjective fatigue symptoms, electromyogram, blinking counts and errors in performance were least in the third set. The results of this study suggest that in order to reduce operators' fatigue on VDT work of the conversation type, countermeasures such as shortening the duration of a single spell of work to less than 60 minutes and taking frequent short intermission are necessary.

Adult↗
PubMed1984

Influence of various experimental conditions on the inhibitory effects of (E)-5-(2-bromovinyl)-2'-deoxyuridine on varicella-zoster virus replication in cell culture.

Inhibition of varicella-zoster virus (VZV) replication by (E)-5-(2-bromovinyl)-2'-deoxyuridine (BVDU) has been examined in vitro under various experimental conditions. The 50% inhibitory dose (ID50) of BVDU for VZV replication in human embryonal fibroblast (HEF) cultures was 0.016 micrograms/ml, if the assay was based on the reduction of visible foci. If the assay was based on the reduction of immunofluorescent foci, the ID50 was 3 times higher. There was no significant difference in ID50, whether the HEF cultures were infected with cell-free or cell-associated VZV. When the HEF cells were infected with VZV at different multiplicities of infection (MOI), the ID50 of BVDU increased in parallel with the increase of MOI. BVDU was normally added immediately after virus infection. However, the addition of BVDU could be delayed until 8 hr after infection without substantial decrease of activity. On the other hand, BVDU did not cause any inhibition of focus formation when it was removed within 8 hr after VZV infection. If removed at 24 or 48 hr after infection, BVDU caused a significant reduction in focus formation. BVDU had no effect on focus formation if added to the HEF cells before virus infection. BVDU was also found to inhibit VZV focus formation in Vero cells, but only at an ID50 that was 5-10 times higher than the ID50 noted in HEF cells.

Animals↗
PubMed1984

Comparative inhibition of DNA polymerases from varicella zoster virus (TK+ and TK-) strains by (E)-5-(2-bromovinyl)-2'-deoxyuridine 5'-triphosphate.

The inhibitory effect of (E)-5-(2-bromovinyl)-2'-deoxyuridine (BVDU) 5'-triphosphate on varicella zoster virus (VZV) DNA polymerase was studied using the parent strain (TK+-VZV) and the mutant strain (TK--VZV). The mutant strain was deficient in thymidine kinase (TK)-inducing activity and resistant to BVDU. In the absence of BVDU, TK--VZV and TK+-VZV induced an equivalent level of viral DNA polymerase activity in human embryo fibroblasts. In the presence of 5 microM BVDU, TK--VZV still induced viral DNA polymerase activity, whereas TK+-VZV failed to do so. BVDU 5'-triphosphate (BVDUTP) was considerably more inhibitory to the TK+- and TK--VZV DNA polymerases than to the cellular DNA polymerases. There were no significant differences in the affinity for dTTP as substrate and the sensitivity to BVDUTP as inhibitor between the TK+- and TK--VZV DNA polymerases. The Km value for dTTP and the Ki value for BVDUTP of the VZV DNA polymerases were 1.43 microM and 0.55 microM, respectively. The inhibitory effect of BVDUTP to VZV DNA polymerase was competitive with respect to the natural substrate.

Antiviral Agents↗