Search PubMed⌕ Search

Biomedical subjects

T Shiota

Publications and source records attributed to T Shiota.

At least 235 records · Page 13Linked to original sources
PubMed1982

Effects of insulin and glucagon on serum amino acid concentrations in liver disease.

The effects of insulin and glucagon administration on serum amino acid levels were investigated in patients with severe liver disease, since simultaneous injection of pancreatic hormones has been recently introduced as a therapeutic approach. The changes in serum amino acid concentrations, as observed 3 h after ceasing a 3 h infusion of insulin and glucagon in 500 ml glucose solution, were an elevation of serum branched chain amino acid (BACA) levels and of the molar ratio of BCAA/aromatic amino acid (AAA) levels in patients with liver cirrhosis. Similar increases of serum BCAA levels during the infusion were also observed in patients with fulminant hepatitis. The results suggest that insulin-glucagon therapy for severe liver disease has no harmful side effects at least with respect to alterations in the serum aminogram.

Amino Acids↗
PubMed1981

The enzymatic synthesis of sepiapterin by chicken kidney preparations.

A chicken kidney preparation which catalyzes the conversion of D-erythro-dihydroneopterin triphosphate to dihydrobiopterin in the presences of Mg2+ and NADPH has been fractionated into three fractions, A2, A1, and B. Fraction A2 in the presence of Mg2+ catalyzes the conversion of D-erythro-dihydroneopterin triphosphate to an unknown intermediate designated compound X. Fraction A1 in the presence of NADPH catalyzes the conversion of compound X to sepiapterin. Fraction B, in the presence of NADPH, catalyzes the conversion of sepiapterin to dihydrobiopterin. Fraction B which is sepiapterin reductase was not studied any further. Fraction A1 is heat-labile and its molecular weight is estimated to be 3.0 x 10(4), whereas fraction A2 is heat-stable and its molecular weight, 7.7 x 10(4). Compound X is labile and its degradation products have been identified to be pterin and pyruvic acid. This information suggests that compound X is 6-(1,2-dioxopropyl)-7,8-dihydropterin.

Alcohol Oxidoreductases↗
PubMed1981

Virulence of Streptococcus mutans: characterization of a serotype g antigen-defective mutants and its revertants.

A mutant of Streptococcus mutans 6715 HSR, which is defective in serotype antigen and designated C307, was shown to exhibit full virulence on buccal, sulcal, and proximal surfaces similar to that of 6715 HSR. In addition, this bacterium caused significant decay on the lingual surfaces. Its colonial morphology and certain biochemical activities which may be related to caries production were distinct from those of 6715 HSR. This mutant adsorbed to saliva-treated hydroxyapatite beads in greater amounts and aggregated in the presence of either sucrose or dextran in excess of that seen with the parent strain. The abilities of C307 to grow and to produce acid from sucrose and to adhere to glass surfaces were similar to that of 6715 HSR. Although revertants of C307 exhibited biological activities and a content of serotype g antigen similar to that of 6715 HSR, the virulence pattern was still unlike the parent strain. These results suggest that the serotype g antigen is not required for the adherence of cells to smooth surfaces or for caries formation and that the loss of this antigen may alter the surface of cells causing enhanced ability of the cells to aggregate and to adsorb to saliva-treated hydroxyapatite beads.

Animals↗
PubMed1981

Provocation experiment: Pneumocystis carinii in several kinds of animals.

Provocation experiments of P. carinii in several kinds of laboratory animals were carried out in an animal house where P. carinii of rat strain had been maintained for several years. The organism propagated in cortisone treated rats, rabbits and mice without difficulty as reported by some authors in the past. The organism also propagated in the lungs of rats which had been bred with protein free diet. The present paper first indicates that guinea pig is susceptible to P. carinii. On the other hand, it becomes evident by repeated experiments, that golden hamster seems to be non-susceptible to P. carinii of rat strain even if enough dose of corticosteroid hormones is given. The presence of non-susceptible animal to a certain strain of P carinii is quite interesting from an epidemiological point of view.

Animals↗
PubMed1981

Further light microscopic studies on morphology and development of Pneumocystis carinii.

In order to add more advance in light microscopic investigation of P. carinii, phase contrast microscopy partly followed by wet giemsa stain and semiultrathin section of the lungs embedded in JB-4 plastic were studied. In phase contrast microscopy, small and large sized trophozoites of P. carinii were clearly recognized. Although movement of trophozoite was not found, rhythmic movement of intracystic bodies with filopodia was often seen in mature cyst. Those living organisms were then directly stained with Giemsa by infiltrating under the coverglass. Thus the organism could be investigated both in unstained and stained conditions. It is noticed with interest that 8 intracystic bodies seem to fill up the cavity of cyst when cell division is completed, then they liberate and become independent into spherical bodies, followed by banana-shaped or amoeboid forms with motility. An emphasis was done that semiultrathin section made from JB-4 plastic embedded lungs was quite useful for investigation of P. carinii infection. Several sizes of mononuclear thin-walked trophozoites, mature and immature cysts, and empty cysts were more clearly distinguished than any other light microscopical method ever reported.

Animals↗
PubMed1981

[Quantitative evaluation of serial 201Tl Myocardial scintigrams after stress testing in ischemic heart disease (author's transl)].

Five normal adults and 31 patients with ischemic heart disease were studied by stress test, and 201Tl was injected one min. before the end of the test. Myocardial scintigrams in three views were recorded at 10 min, 1 and 2 hours (phase 0, 1 and 2) after the injection. The myocardial wall was geometrically divided into 5 segments. At the area where the count rate (Cts) was highest in phase 0 scintigrams, the washout rate from phase i to j was defined as WRij = (maxCtsi-maxCtsj)/maxCtsi where Ctsi denoted Cts at phase i in the relevant area. The redistribution index (Rdsij) in each segment was defined as Rdsij = [Ctsi X WRij + (Ctsi - Ctsj)]/Ctsi, where Ctsi denoted Cts at phase i in the segment. The ischemic segment was identified as 70% or less of maxCts 0, while the infarcted segment by VCG in phase 0 scintigram. Mean values of Rds 02 in the normal, ischemic and infarcted segments were -6.1 +/- 5.6, 9.7 +/- 7.0 and 3.5 +/- 7.2%, respectively, and the differences were statistically significant (p less than 0.001). All the 26 patients with anginal except one showed WR 12/WR 01 greater than 1.0. When the peak pressure rate product that attained at the test was 200 or more, it was significantly correlated with WR 02 (r = 0.80). The Redistribution index was helpful in quantitative assessment of the ischemic segments. The finding of WR 12 greater than WR 01 after the stress was reliable in suggesting myocardial ischemia.

Adult↗
PubMed1980

Virulence of Streptococcus mutans: revertants of mutant C4.

Mutant C4, a poor plaque-forming mutant of Streptococcus mutans 6715-HSR, was employed to obtain isolates resembling the parent strain (a plaque former). Seventeen presumptive revertants, as identified by colonial morphology, were isolated from mutant C4 after enrichment cycles in a sucrose-glass beads medium. These isolates displayed properties which resembled the parent in ability to produce plaque, patterns of fermentation, and resistance to streptomycin. In a detailed study, five selected isolates were found to be similar to the parent type 6715-HSR with respect to content of the serotype antigen, sucrose- or dextran-induced cell aggregation, glucosyltransferase and adherence activities, and cariogenicity. Thus, in selection for revertants to parental colonial morphology, the pleiotropic changes in plaque formation, adherence, glycosyltransferase activity, and virulence demonstrated by C4 all concomitantly reverted to their parental phenotypes.

Animals↗
PubMed1980

Virulence of Streptococcus mutans: immunochemical characterization of a serotype g-defective mutant (C307).

A mutant of Streptococcus mutans 6715 wild type designated C307 has been shown to possess a small amount of either Lancefield- or Rantz-Randall-extractable serotype antigen. Quantitative analysis employing combined immunoabsorption and radial immunodiffusion of anti-S. mutans serotype-specific serum demonstrated that C307 exhibited less than 1% of the amount of serotype g antigen normally expressed in S. mutans 6715 wild type.

Antigens, Bacterial↗
PubMed1980

Virulence of Streptococcus mutans: in vivo reversion of a low-virulence mutant results in partial displacement and pathogenesis.

A mutant of Streptococcus mutans 6715 wild type (WT), designated C4, has been shown previously to be defective in glucosyltransferase synthesis of insoluble glucan and to have low virulence in monoassociated gnotobiotic rats. The present investigation was concerned with the detection of WT-like variants of C4 in monoassociated rats, the supplantation of C4 by these WT-like organisms, and finally, the pathogenic potential of these WT-like organisms in gnotobiotic rats. In the first series of longitudinal studies with C4-monoassociated rats, WT-like organisms were detected at a low frequency (0.001%) in oral swab samples from only one of four cages of animals analyzed on day 7 after infection (age 27 days). The frequency of variants isolated from animals in the one cage increased, and by age 45 days these organisms represented approximately 1% of the mandibular plaque flora. After random redistribution of rats in the four cages (age 45 days), microbial analysis of oral swab samples (age 60 days) demonstrated the presence of variants in samples taken from rats in all four cages. The frequency of recoverable variants increased in older animals (age 90 days) and correlated with high caries activity. WT-like organisms were transmissible, since offspring (age 45 days) from these animals had high levels of variants as well as high caries activity. Similar results were obtained in a second longitudinal study; however, variants, although present in all four cages, were not detected until rats were 45 days old. All variant isolates exhibited morphological, biochemical, and in vivo virulence characteristics more similar to S. mutans 6715 WT than to C4. In vitro mixing experiments with C4 and either WT or a selected variant suggested that C4 was rapidly displaced by WT organisms. The results of this investigation demonstrate that the glucosyltransferase-defective, low-virulence C4 reverts to virulent WT-like organisms in vivo which compete more favorably for smooth surfaces than C4. Subsequently, these variants reached significant numbers in plaque which correlated with increased dental caries.

Animals↗
PubMed1980

Virulence of Streptococcus mutans: restoration of pathogenesis of a glucosyltransferase-defective mutant (C4).

Previous studies have shown that a mutant (designated C4) of Streptococcus mutans 6715 wild type (WT) is defective in glucosyltransferase (GTF)-synthesized insoluble glucan and is avirulent in gnotobiotic rats. This study investigated the factors which would render this mutant virulent in gnotobiotic rats. Microbial analysis of plaque from gnotobiotic rats (45 days old) infected with a mixture of C4 and virulent S. mutans PS-14 (approximately 15,000 C4 organisms to each S. mutans PS-14) yielded higher numbers of C4 organisms than S. mutans PS-14. These animals exhibited significantly lower caries scores than did gnotobiotic rats (age, 45 days) monoassociated with S. mutans PS-14. Similar mixed infection studies using C4 and an avirulent, aggregation-defective mutant of S. mutans 6715 WT (designated UAB 165) which exhibits GTF activity similar to that of the parent strain resulted in plaque consisting almost exclusively of UAB 165 and low caries activity. However, high levels of both C4 and UAB 165 in plaque and high caries activity were observed in gnotobiotic rats infected at weaning with C4 followed by UAB 165 3 days later. When dried S. mutans 6715 WT culture supernatant containing GTF activity was mixed with diet provided rats monoassociated with C4, significant caries activity was observed. Insoluble glucan supplemented in diet did not restore C4 to virulence; however, admixture of suboptimal GTF-rich supernatant with insoluble glucan and C4 resulted in high caries activity in gnotobiotic rats. These results suggest that in vivo restoration of pathogenesis of a GTF-defective mutant of S. mutans can be achieved either by complementation with a mutant defective in aggregation properties or by providing exogenous GTF and glucan from the parent S. mutans 6715 WT.

Animals↗
PubMed1979

Plasma ADH levels during heart surgery.

1) Plasma ADH levels measured by bioassay in the group with extracorporeal circulation were 2.3 +/- 0.6 muu/ml before surgery and 6.6 +/- 1.8 muu/ml during anesthesia. They increased to 196.5 +/- 62.3 muu/ml or about 100 times greater than before surgery during cardiopulmonary bypass. 2) In the group without extracorporeal circulation, plasma ADH levels were 1.5 +/- 0.9 muu/ml before surgery and increased to 44.1 +/- 15.2 muu/ml during operation. 3) After operation decrease in plasma ADH level was relatively rapid in both groups. It became three times that of the control level in the morning of the next day. 4) Marked increase in plasma ADH level during cardiopulmonary bypass was much the same as it was during hemorrhagic shock in dog experiments. 5) Fall in mean arterial blood pressure and loss of pulsatile blood flow will play main roles in this marked increase in ADH during cardiopulmonary bypass through stimulation of arterial baroreceptors and probably chemoreceptors. 6) In two cases with mitral stenosis, increase in plasma ADH during cardiopulmonary bypass was lesser than the other heart diseases.

Adult↗
PubMed1979

[Treatment of Diphyllobothrium latum and Taenia saginata infections with aminosidine (author's transl)].

Recently, it has been known that the aminosidine has marked anthelmintic efficacy against tapeworm. In this investigation, aminosidine was used for treating 14 cases with Ciphyllobothrium latum infection and 5 cases with Taenia saginata infection. Aminosidine was administered orally in a single dose of 50 mg/kg, followed by a purge after the treatment. Fourteen patients with D. latum infection and 5 patients with T. saginata infection expelled long strobila in all cases. Although only 7 scolices of 18 worms of D. latum were found in the stool and no scolex of T. saginata was found, follow-up examination for a long period showed no evidence of remaining infection with one exception of D. latum. Mild nausea, vomiting and abdominal pain were observed in only one of 19 cases given aminosidine. But in the other 18 cases, no side effects were encountered. It was concluded that aminosidine is safe, effective therapeutic agent for the treatment of cestodiasis in man.

Adolescent↗