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Biomedical subjects

H Shibata

Publications and source records attributed to H Shibata.

At least 739 records · Page 41Linked to original sources
PubMed1982

Ultrastructure of the regenerating growth cones of catecholamine nerve terminals in rat hypothalamic nuclei after 5,7-dihydroxytryptamine administration.

Ultrastructure of the regenerating growth cones of catecholamine axons is examined in the paraventricular nucleus and median eminence of the rat. Growth cones are observed during 1 to 4 months, and most frequently at 2 months, after the administration of 300 microgram of 5,7-DHT in the lateral ventricle. The growth cones of catecholamine axons are characterized by an accumulation of branching smooth endoplasmic reticula which contain dense material.

5,7-Dihydroxytryptamine↗
PubMed1982

Antibacterial action of condensed phosphates on the bacterium Streptococcus mutans and experimental caries in the hamster.

Condensed phosphates (CP: Na salts of pyro-, tripoly-, tetrapoly-, pentapoly-, hexameta- and ultra-; K salts of pyro- and poly-) used as food additives depressed the growth of seven strains of Streptococcus mutans (serotype a-g) as assessed by disc diffusion methods. Minimal inhibitory concentrations (MIC) of CP on growth of strain K1-R (g) in a chemically defined medium were measured turbidimetrically. Commercial grade CP (CP used) had the same growth inhibitory effects as purified linear type CP and they were superior to the cyclic type CP. The MIC of CP for Strep. mutans appeared to be related to their chelating capacity. As the growth inhibition by CP was reversed by the addition of divalent metal ions (Ca2+, Mg2+ or Mn2+), the chelating capacity of CP was apparently responsible for their antibacterial action. The antibacterial action of CP seemed largely bacteriostatic. Condensed phosphates depressed lactate production from glucose and sucrose by the cells of strain K1-R. A similar inhibition was produced by the supernatant of heated human saliva. Condensed phosphates depressed insoluble glucan production from sucrose by the cells of strain K1-R. The inhibition of sugar metabolism may be due to the interference of sugar transport into Strep. mutans induced by the chelation effects of CP. Hamsters were inoculated orally with strain K1-R and reared on the high-sucrose diet No. 2000 supplemented with 2 per cent (w/w) CP for 60 days. Dietary supplements of CP were associated with reduced caries activity (p less than 0.01) and plaque formation (p less than 0.05). The antibacterial actions of CP could be responsible for these caries-inhibitory effects.

Animals↗
PubMed1982

A correlative quantitative study comparing the nerve fibers in the cervical sympathetic trunk and the locus of the somata from which they originate in the rat.

Correlative quantitative analyses were performed on the rat comparing the number of fibers in the cervical sympathetic trunk (CST) and the horseradish peroxidase (HRP)-labeled neurons in the superior cervical sympathetic ganglion (SCG), stellate ganglion, as well as in the spinal cord. The total number of nerve fibers in the left CST was 4180 +/- 169 (mean +/- S.E.M.) among which 92 +/- 3 (mean +/- S.E.M.) were myelinated. The diameter of unmyelinated fibers was 0.68 +/- 0.22 (mean +/- S.D.) microns and showed single-peaked distribution. After the application of HRP to the proximal cut end of the CST, labeled neurons were found in the stellate ganglion as well as in the ipsilateral spinal cord from C7 to T4 segments. The total number of HRP-labeled neurons in the spinal cord was 1334 +/- 45 (mean +/- S.E.M.) with the range between 844 and 1808. Ninety-nine percent of labeled neurons were located in the intermediolateral column and in the lateral funiculus while 1% were in the intercalated region and central autonomic area. Labeled neurons were encountered only sporadically in the dorsal root ganglia (DRG) from C8 to T3 level. After the application of HRP to the distal cut end of the CST, about 200 labeled neurons were observed in the caudal part of the SCG. The present results were discussed with special reference to the organization of the CST of the rat.

Animals↗
PubMed1982

Ozone decontamination of bioclean rooms.

To establish a convenient method for decontaminating bioclean rooms, the effect of ozone at 80 mg/m3 for 72 h was compared with formaldehyde vaporization at an initial concentration of 150 mg/m3 with a gradual decrease to 20 mg/m3 during 72 h. Ozone was found to be inferior to formaldehyde in activity. When the bioclean room was decontaminated twice with ozone, the mean colony count per 10 cm2 was decreased to about the same level as when formaldehyde was used. Ozone had a strong caustic effect upon rubber materials. Despite these disadvantages, ozone decontamination was demonstrated to be superior to formaldehyde vaporization because of convenience, insignificant inhalation of the disinfectant by the hospital staff, and very rapid expulsion of the gas after ventilation. Because the disadvantages of ozone can be easily controlled, this study suggests that ozone decontamination is a promising method for maintaining bioclean rooms.

Bacillus subtilis↗
PubMed1982

Effects of gravity and branching on longitudinal gas mixing in glass tube models.

We investigated the effects of gravity and branching on gas mixing in glass tube models. The mixed gas (5% He and 5% SF6) was made to flow through a straight tube and tubes with bifurcated branches, and the effective axial diffusion coefficient (Deff) was measured. The direction of the branches was varied from upward to downward by 90% turns, and the flow distribution to each branch was separately controlled. In the case of a straight horiontal tube, the flow velocity dependency of the Deff of He and SF6 was observed as we expected from Aris' equation. In the case of glass tubes with branches, the Deff of SF6 was greater in the downward-directed branches than it was in the upward-directed branches when gas mixing occurred at the front of the gas mixture; however, when gas mixing occurred at the tail, the opposite effects were observed. These characteristics were more marked at slower flow rates and when the flow to each branch was different. Our findings suggest that gravity has an effect on gas mixing in glass tube airway models, especially at a low flow rate and uneven flow distribution.

Gravitation↗
PubMed1982

Hypoxic suppression of dietary-induced component of resting metabolism in rats.

Wistar rats fasted for 48 h were exposed to hypoxia (9.5% O2 in N2) at ambient temperatures (Ta) of 13.5, 24.5, and 32.0 degrees C. In normoxic environment, fasted rats showed significantly lower values of oxygen consumption (VO2), dry heat loss (R + C + K), and colonic temperature (Tcol) than in fed counterparts. The extent of decrease in each parameter was nearly same at any Ta. On exposure to hypoxia, fed rats showed a significant decrease in VO2, (R + C + K), and Tcol at any Ta. The decrease was particularly great at Ta 13.5 degrees C. In contrast to fed rats, fasted rats showed a significant decrease in all of these parameters only at Ta 13.5 degrees C. No such decrease was observed at Ta 24.5 and 32.0 degrees C. However, a significant difference in Tcol was found at Ta 24.5 degrees C in fasted rats between normoxic and hypoxic environments. Moreover, there was no statistically significant difference between fed and fasted rats in each parameter at any Ta in hypoxia. These results suggest that hypoxia suppresses both dietary-induced and cold-induced components of metabolism in rats.

Animals↗
PubMed1982

Inhibition of shivering as a cause of metabolic suppression with norepinephrine in warm- and cold-acclimated rats.

The metabolic response of warm-acclimated (25 degrees C for 4 weeks) and cold-acclimated (5 degrees C for 4 weeks) rats to infused norepinephrine (NE) (0.5-4 micrograms/(kg.min)) was measured at an ambient temperature of 13 degrees C, either before or after sinoaortic denervation. In warm-acclimated rats, vigorous shivering consistently occurring at 13 degrees C was greatly inhibited by NE in a dose of 2-4 microgram/(kg.min). After sinoaortic denervation, no such inhibition of shivering was observed. In cold-acclimated rats, NE did not suppress but increased heat production at this temperature, no visible shivering being noticed. Phenylephrine, a alpha-adrenergic stimulant, increased blood pressure and decreased heart rate to the same extent in both groups of rats at this temperature. NE suppressed heat production even in cold-acclimated rats at -5 degrees C, where the animals exhibited shivering. These results indicated that NE infusion inhibits shivering via the sinoaortic baroreceptor reflex, in both warm-acclimated and cold-acclimated rats. The non-occurrence of metabolic suppression in cold-acclimated rats after norepinephrine infusion in the 13 degrees C environment may be due to an absence of shivering which is suppressed at this temperature.

Acclimatization↗
PubMed1982

Baroreflex suppression of nonshivering thermogenesis in rats.

The effects of an elevation of arterial blood pressure (BP) on heat production (M) and interscapular brown adipose tissue temperature (Tbat) were studied at 15 degrees C in unanesthetized 5 degrees C-acclimated rats. The elevation in blood pressure (BP), caused by phenylephrine (PHE: 5-30 micrograms/(kg x min)) infusion for 10 min, decreased M and Tbat accompanied by a marked bradycardia. The decrease in M was not due to the suppression of shivering, because shivering did not appear under the present experimental conditions. After sinoaortic baroreceptor denervation, PHE infusion failed to produce these changes. After premedication with atropine, PHE infusion suppressed M and Tbat without the bradycardia. These results indicate that nonshivering thermogenesis (NST) in the brown adipose tissue (BAT) is suppressed by a sinoaortic baroreceptor reflex in response to an elevation of BP. Since metabolism of BAT is controlled by the sympathetic nervous system, the baroreflex inhibition of NST in the BAT may be largely attributed to the decrease of sympathetic nervous outflow to the BAT.

Adipose Tissue, Brown↗
PubMed1982

Serotype specificity for some biochemical characteristics of Streptococcus mutans.

Representative strains of Streptococcus mutans serotypes a to g were examined for characteristic in vitro traits thought to contribute to cariogenic virulence. Most strains of serotypes a, d and g produced higher proportion of the cell-associated, alkali-soluble glucans from sucrose. Cells of these serotypes agglutinated upon addition of high-molecular-weight dextrans or sucrose, but did not adsorb well to saliva-coated hydroxyapatite. Serotype c, e and f strains, by contrast, synthesized higher proportions of the extracellular, water-soluble glucans and adsorbed well to saliva-coated hydroxyapatite particles but did not agglutinate with dextrans. Thus, serotype a, d and g S. mutans and type c, e and f S. mutans formed two separate groups on the basis of these biochemical properties. Synthesis of intracellular iodophilic polysaccharides from glucose showed a different pattern of distribution among the serotypes: types a, d, e and f synthesized large amounts of this polysaccharide, while all but one of the eight type c and g strains produced only small amounts. Serotype b S. mutans seemed to constitute a separate subgroup in terms of the above in vitro traits.

Agglutination↗
PubMed1982

[Radiotherapy combined with pepleomycin administration for the treatment of esophageal cancer].

A combined therapy of pepleomycin (NK-613) and radiation was performed in 15 cases of esophageal and cancer. Twelve cases out of 15 were inoperable, and 3 cases were operable. NK-631 was administered by drip intravenous injection at a dose of 5 mg per day for 3 consecutive days weekly, aiming at total dose of 60-120 mg. Tumor regression rates, which were measured by planimeter on esophagogram, were 42-92% (mean 72%): two cases were more than 90%, and more than 50% in 12 cases. An average of the survival period of 15 cases was 57 weeks with 7 cases (46.7%) of 1 year survival, 2 cases (13.3%) of 2 year survival. The side effects of NK-631 observed in the present study consisted of fever 6, stomatitis 2, skin rash 2, and reversible pneumonitis 2. This study suggests that NK-631 exhibit remarkable anti-tumor effects on esophageal carcinoma, and seem to be less toxic.

Aged↗
PubMed1982

[Gastrointestinal transit in the chicken using 198Au-colloid as a marker (author's transl)].

Gastrointestinal transit in the chicken was investigated by using 198Au-colloid as a marker. Gastrointestinal transit was determined following administration of a 198Au-colloid solution (370 kBq (10 microCi), 0.5 ml) into the proventriculus by measuring the distribution of radioactivity in the gastrointestine. Most of 198Au-colloid administered into the proventriculus was transferred instantly to the gizzard and subsequently, some part of it quickly to the duodenum and the upper segment of the jejunoileum. A considerable quantity of 198Au-colloid in the duodenum, the upper and middle segment of the jejunoileum regurgitated to the gizzard. 198Au-colloid transferred to the caecum was retained for a long time (more than 48 hours) in these segments. A part of 198Au-colloid was found in the feces 90 to 120 minutes after administration into the proventriculus and the greater part of it was excreted into the feces 24 to 48 hours. Subcutaneous administration of acetylcholine (2 mg/kg) increased the gastrointestinal transit but atropine (2 mg/kg) decreased.

Acetylcholine↗
PubMed1982

[Effects of cefoxitin in the treatment of severe infections in patients with hematopoietic disorders].

Cefoxitin (CFX) at a daily dose of 3 to 12 grams was administered to patients who had hematopoietic disorders as underlying diseases and having severe infections. Efficacy and safety of the drug were evaluated. The underlying diseases in the 64 patients included in the evaluation of efficacy were acute myelocytic leukemia (30 cases), acute lymphocytic leukemia (9), acute promyelocytic leukemia (3), acute monocytic leukemia (2), chronic myelocytic leukemia-blastic crisis (10), erythroleukemia (2), malignant lymphoma (2), aplastic anemia (2), and others (4). The infections were septicemia in 3 patients, suspected septicemia in 47, respiratory tract infections in 7, oral infections in 3, urinary tract infections in 2, and others in 2. The clinical efficacy of CFX was 'excellent' in 13 patients, 'good' in 26, 'fair' in 6, 'poor' in 19 for an efficacy rate of 60.9%. The efficacy rate classified according to infections was 66.7% in septicemia, 66.0% in suspected septicemia, 42.9% in respiratory tract infections and 66.7% in oral infection. The organisms isolated from the patients with septicemia were E. coli in 2 patients and B. cereus in 1. B. cereus was not susceptible to CFX. The efficacy rate was 60.0% in the 10 patients whose causative organisms were identified and 61.1% in the 54 patients whose causative organisms were not identified. There was no significant difference in the efficacy rate between the patients who had failed to respond to prior antibiotic therapy and those treated with CFX from the beginning. The efficacy rates for the former group (23 patients) and for the latter group (41 patients) were 56.5% and 63.4%, respectively. The efficacy rate in patients with an initial neutrophil count less than 500/mm3 (35 cases) and from 501 to 1,000/mm3 (13 cases) were 57.1% and 76.9%, respectively. Side effects which might have been caused by CFX were skin eruptions in 2 patients (2.6%) and transient elevation of GOT and GPT in 1 patient (1.3%) among 76 patients who were evaluated for safety. CFX was considered to be a markedly useful and safe drug in the treatment of patients with hematopoietic disorders who developed severe infections.

Adolescent↗