Biomedical subjects

Y Hashimoto

Publications and source records attributed to Y Hashimoto.

At least 955 records · Page 53Linked to original sources

PubMed1992

Flow cytometric analysis of pig epidermal keratinocytes: effects of tape stripping.

Tape stripping is a dynamic in vivo model for the induction of synchronized keratinocyte proliferation. We investigated the cell kinetics of pig epidermis by DNA-flow cytometric analysis, which was compared with [3H]thymidine incorporation mitotic counts and 2-[3H]-deoxy-D-glucose uptake. The stripping was standardized and confirmed histologically by the observation of complete removal of horny layer. Following the stripping, the proportion of cells in S-phase showed no remarkable change until 12 h. This was followed by a spike-like increase in the S-phase cells, the peak of which was reached at 24 h. This gradually decreased and returned to basal levels by 48 h. The cells in G2/M fraction initially decreased; the lowest value was obtained at 12 h. This was followed by a marked increase in the G2/M fraction, the peak of which was at 36 h. The keratinocytes in G2/M fraction gradually returned to basal levels by 96 h. [3H]Thymidine uptake and mitotic counts were mostly parallel with the data of the flow cytometric analysis, suggesting the latter as being a reliable system for cell kinetic analysis. The glucose uptake initially decreased (at 6 h following the stripping) and then increased at 24 h. Histologically the stripped epidermis regained its horny layer almost completely by 72 h following the stripping; this was occasionally accompanied by a moderate acanthotic change thereafter.

Animals↗

PubMed1992

Hyperpolarizing interplexiform cell of the dace retina identified physiologically and morphologically.

One type of interplexiform cell (IPC) in the dace retina was discriminated physiologically from other cell classes and identified morphologically with HRP staining. This type responded with slow hyperpolarizing potentials to white diffuse light, and in addition a slow hyperpolarization (after potential) was observed after the cessation of light with relatively high intensities. The latency of the ON phase of the response was always longer than that of the second-order neurons and the amacrine cells. Morphologically, this type of IPC was similar in appearance with the dopaminergic IPC. The conventional synaptic specialization between this type of IPC and horizontal cells was observed, and the IPC was presynaptic.

Animals↗

PubMed1992

Comparison of the relaxant effects of diazepam, flunitrazepam and midazolam on airway smooth muscle.

The mechanisms by which benzodiazepines produce muscle relaxation and respiratory depression are not known, but they may include actions on peripheral benzodiazepine receptors or central GABA receptors, or a direct action on airway smooth muscle may also be involved. We have compared, therefore, the effects of diazepam, flunitrazepam and midazolam on airway tone by measuring isometric tension of guineapig trachealis muscle. Cumulative concentrations of diazepam, flunitrazepam and midazolam caused concentration-dependent relaxation of resting tone in the tracheal smooth muscle with no significant differences in pD2 values (-log EC50--an index of potency) or intrinsic activities (% of maximum response) for relaxations for the three compounds. Pretreatment with propranolol 10(-6) mol litre-1, flumazenil 10(-7) and 10(-6) mol litre-1 or PK11195 10(-6) mol litre-1 had no effect on diazepam- or midazolam-induced relaxation. Diazepam 3 x 10(-6) mol litre-1 pretreatment shifted the concentration-response curves for acetylcholine, histamine and serotonin (5-HT) to the right by a factor of approximately 2. Flunitrazepam 3 x 10(-6) mol litre-1 pretreatment also shifted the curves for histamine and 5-HT similarly to the right, whereas midazolam pretreatment did not inhibit any agonist-induced contractions. These results suggest that benzodiazepines relax airway smooth muscle, not via neural pathways or central and peripheral benzodiazepine receptors, but by a direct action on airway smooth muscle.

Animals↗

PubMed1992

Elderly, conscious patients have an accentuated hypotensive response to nitroglycerin.

There is no adequate explanation for the highly variable response of systemic blood pressure to nitroglycerin (glyceryl trinitrate [GTN]). Aging produces cardiovascular changes that should alter the effects of GTN, but elderly patients usually have been excluded from studies of GTN. Accordingly, the authors compared the effects of GTN on systemic blood pressure in elderly and younger patients. Fifty-three patients, aged 49-87 (with 30 patients older than 70), were studied. Before elective vascular surgery, 14 patients received an infusion of placebo; 26, a constant infusion of GTN; and 13, a stepwise increasing infusion of GTN. After a standardized anesthetic induction and the start of surgery, the identical infusion protocols were repeated in each group. Data on GTN infusion rate, arterial blood pressure, and GTN concentrations versus time, age, and other potentially influencing variables were pooled for analysis. Before anesthesia and surgery, GTN more commonly caused excessive hypotension in patients older than 70 yr than in younger patients, but none of the patients had complications. A repeated-measures model analysis indicated that age significantly influenced the effects of GTN on blood pressure. That is, patients who are in their 70s who receive 0.5 micrograms.kg-1.min-1 of GTN are predicted to experience a twofold greater decrease in systolic arterial pressure (approximately 33 mmHg) than patients in their 50s. However, no apparent effect of age on intraoperative GTN responsiveness was discernible nor was a predictable relationship found between the preoperative and intraoperative responsiveness or between arterial concentrations of GTN and blood pressure or age. Therefore, the authors conclude that, in the absence of the effects of anesthesia and surgery, elderly patients have a more pronounced blood pressure response to GTN than younger patients. Furthermore, the authors conclude that preoperative blood pressure responsiveness to GTN is not a reliable predictor of intraoperative responsiveness.

Aged↗

PubMed1992

Staphylococcus piscifermentans sp. nov., from fermented fish in Thailand.

New coagulase-negative staphylococci were isolated from fermented fish in Thailand. These organisms were differentiated from other Staphylococcus species on the basis of DNA relatedness and biochemical characteristics. Staphylococcus piscifermentans sp. nov. is described, and the type strain is strain SK03 (= NRIC 1817 = JCM 6057 = TISTR 824).

Animals↗

PubMed1992

Three new species of the genus Peptostreptococcus isolated from humans: Peptostreptococcus vaginalis sp. nov., Peptostreptococcus lacrimalis sp. nov., and Peptostreptococcus lactolyticus sp. nov.

We describe three new species of the genus Peptostreptococcus which were isolated from human specimens and were tentatively identified as Peptostreptococcus prevotii. These three organisms were not homologous with previously described type strains of the genus Peptostreptococcus. A total of 12 strains that were identified biochemically as P. prevotii were divided into five independent DNA similarity groups; 10 of these strains were divided into three similarity groups which exhibited significant phenotypic differences from previously described species. Therefore, we propose the following new species: Peptostreptococcus vaginalis for group 1 strains, Peptostreptococcus lacrimalis for group 2 strains, and Peptostreptococcus lactolyticus for group 3 strains. The type strain of P. vaginalis is strain GIFU 12669 (= JCM 8138), the type strain of P. lacrimalis is strain GIFU 7667 (= JCM 8139), and the type strain of P. lactolyticus is strain GIFU 8586 (= JCM 8140).

Bacterial Typing Techniques↗

PubMed1992

Isolation and characterization of Shewanella alga from human clinical specimens and emendation of the description of S. alga Simidu et al., 1990, 335.

Genetic and phenotypic studies on the strains biochemically identified as Shewanella putrefaciens, which had a G+C content ranging from 52 to 54 mol% were conducted. The moles percent G+C of the type strain of S. putrefaciens is 46. Surprisingly, DNA homology experiments revealed that all these strains are genetically related to Shewanella alga (which was reported to produce tetrodotoxin), not to the type strain of S. putrefaciens. In this study, we reidentified clinical strains of S. putrefaciens which have a high range of moles percent G+C, as does S. alga. We also characterized the reidentified strains and found that the original description of S. alga (U. Simidu, K. Kita-Tsukamoto, T. Yasumoto, and M. Yotsu, Int. J. Syst. Bacteriol. 40:331-336, 1990) is insufficient to identify this strain. An emended description of S. alga is given.

Animals↗

PubMed1992

Development of a host-vector system in a Rhodococcus strain and its use for expression of the cloned nitrile hydratase gene cluster.

Two different types of plasmid were isolated from strains of Rhodococcus rhodochrous. Two plasmids, of the same type but from different strains, were combined with Escherichia coli plasmids carrying antibiotic resistance markers to develop E. coli-Rhodococcus shuttle vectors. The ampicillin and kanamycin resistance markers served for selection in Rhodococcus. Electroporation was used to introduce recombinant plasmid DNA into R. rhodochrous ATCC 12674 at a frequency of 5 x 10(7) transformants per microgram DNA. With these host-vector and transformation systems, the nitrile hydratase and amidase genes of a Rhodococcus strain were introduced into the host strain and were efficiently expressed.

Acrylamides↗

PubMed1992

alpha-l-Arabinofuranosidase from Radish (Raphanus sativus L.) Seeds.

An alpha-l-arabinofuranosidase has been purified 1043-fold from radish (Raphanus sativus L.) seeds. The purified enzyme was a homogeneous glycoprotein consisting of a single polypeptide with an apparent molecular weight of 64,000 and an isoelectric point value of 4.7, as evidenced by denaturing gel electrophoresis and reversed-phase or size-exclusion high-performance liquid chromatography and isoelectric focusing. The enzyme characteristically catalyzes the hydrolysis of p-nitrophenyl alpha-l-arabinofuranoside and p-nitrophenyl beta-d-xylopyranoside in a constant ratio (3:1) of the initial velocities at pH 4.5, whereas the corresponding alpha-l-arabinopyranoside and beta-d-xylofuranoside are unsusceptible. The following evidence was provided to support that a single enzyme with one catalytic site was responsible for the specificity: (a) high purity of the enzyme preparation, (b) an invariable ratio of the activities toward the two substrates throughout the purification steps, (c) a parallelism of the activities in activation with bovine serum albumin and in heat inactivation of the enzyme as well as in the inhibition with heavy metal ions and sugars such as Hg(2+), Ag(+), l-arabino-(1-->4)-lactone, and d-xylose, and (d) results of the mixed substrate kinetic analysis using the two substrates. The enzyme was shown to split off alpha-l-arabinofuranosyl residues in sugar beet arabinan, soybean arabinan-4-galactan, and radish seed and leaf arabinogalactan proteins. Arabinose and xylose were released by the action of the enzyme on oat-spelt xylan. Synergistic action of alpha-l-arabinofuranosidase and beta-d-galactosidase on radish seed arabinogalactan protein resulted in the extensive degradation of the carbohydrate moiety.

Journal Article↗

PubMed1992

Comparison of Borrelia burgdorferi isolated from humans and ixodid ticks in Hokkaido, Japan.

Four spirochetal isolates (JEM1 to JEM4) were obtained from cutaneous lesions of patients manifesting erythema chronicum migrans in Hokkaido, Japan. In the protein profiles by SDS-PAGE and the reactivities with monoclonal antibodies (H5332 and H9724) by immunoblotting, all the human isolates were identical with the tick isolates from Ixodes persulcatus. These data indicate that I. persulcatus is an important vector of Lyme disease for humans in Japan.

Animals↗

PubMed1992

Proposal of Burkholderia gen. nov. and transfer of seven species of the genus Pseudomonas homology group II to the new genus, with the type species Burkholderia cepacia (Palleroni and Holmes 1981) comb. nov.

Based on the 16S rRNA sequences, DNA-DNA homology values, cellular lipid and fatty acid composition, and phenotypic characteristics, a new genus Burkholderia is proposed for the RNA homology group II of genus Pseudomonas. Seven species in this group were transferred to the new genus. Thus seven new combinations, Burkholderia cepacia (Palleroni and Holmes 1981), Burkholderia mallei (Zopf 1885), Burkholderia pseudomallei (Whitmore 1913), Burkholderia caryophylli (Burkholder 1942), Burkholderia gladioli (Severini 1913), Burkholderia pickettii (Ralston et al 1973) and Burkholderia solanacearum (Smith 1896) were proposed.

Amino Acids↗

PubMed1992

Species difference among experimental rodents in induction of P450IA family enzymes by 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine.

Rats, mice, hamsters and guinea pigs were given an i.p. injection of 2-amino-1-methyl-6-phenyl-imidazo[4,5-b]pyridine (PhIP), a protein-derived pyrolysate component present in cooked foods, and inductions of cytochrome P450 (P450) in the liver and kidney of these animals were examined. The activity and amount of P450s corresponding to the rat P450IA1 and P450IA2 were assessed by means of a bacterial mutation test using 3 carcinogenic heterocyclic aromatic amines including PhIP as substrates and by Western blotting with a monoclonal antibody reactive with both P450IA1 and P450IA2. In rats, PhIP induced P450IA1, P450IA2 and a new but unspecified P450 isozyme in the liver, and induced P450IA1 in the kidney. However, PhIP induced none of these P450 isozymes in mice, hamsters and guinea pigs.

Amines↗

PubMed1992

HLA-DP antigen and Takayasu arteritis.

Sixty-four patients with Takayasu arteritis and 317 healthy individuals in the Japanese population were examined for HLA-A, -B and -C alleles by serological typing and for HLA-DR, DQ and DP alleles by DNA typing using PCR/SSOP analysis. The frequencies of HLA-Bw52, DRB1*1502, DRB5*0102, DQA1*0103, DQB1*0601 and DPB1*0901 alleles were significantly increased and the frequencies of HLA-Bw54, DRB1*0405, DRB4*0101, DQA1*0301, DQB1*0401 alleles were significantly decreased. Strong linkage disequilibria among the increased alleles and among the decreased alleles were evident in the Japanese population. Therefore, the combination or haplotype of HLA-Bw52-DRB1*1502-DRB5*0102-DQA1*0103-DQB1*0601 -DPA1*02-DPB1*0901 may confer susceptibility to Takayasu arteritis while another combination or haplotype of HLA-Bw54-DRB1*0405-DRB4*0101-DQA1*0301-DQB1++ +*0401 may confer resistance to the disease. Because this is the first evidence for the association between an HLA-DP allele and Takayasu arteritis, we examined the nucleotide sequences of the DPB1*0901 allele from a patient and her healthy relatives and found no difference. The disease is therefore not caused by a mutated DPB1 gene.

Alleles↗

PubMed1992

[A lectin histochemical study of the epidermis off the skin and the hoof of horses].

Carbohydrate moieties of cell membranes in the epidermis of equine skin and hoof were investigated using lectin-histochemistry. The loss of desmosomes during keratinization leads to a reduced lectin affinity. Lectin binding capacity of the intercellular matrix in the stratum corneum of the epidermis is weak compared to that of the intercellular kitt of the hoof. Qualitative differences in lectin binding of the intercellular kitt of different hoof segments correlate with the quality of the horn in the respective areas.

Animals↗

PubMed1992

[Genetic identification of 25 Legionella species by modified microdilution plate hybridization, and its evaluation with isolated strains].

Modified microdilution plate hybridization was used for genetic identification of 25 Legionella species. The cell wall of the isolate was broken down by glass beads. And the DNA was extracted, labeled photo-reactive biotin, and hybridized with reference DNAs immobilized in microdilution wells. Hybridized DNAs were detected by colormetric method. Each type strain of 25 Legionella species was clearly differentiated by this method. Among 103 clinical and environmental Legionella strains, 97 strains were genetically identified by this method. 60 strains were identified as the same species as by the conventional method. Concerned with ten strains that had been serologically identified as L. bozemanii, two strains isolated from the human lung were genetically identified as L. bozemanii, but the remaining environmental 8 strains were identified as L. anisa. Among the 35 strains of legionellae that had been unidentified at species level, by physiological and serological tests, 27 strains were genetically identified as L. pneumophila, 1 strains as L. feeleii, and another, as L. anisa, but 6 strains were not identified. We found that three strains among the 6 strains belong to a single species of genus Legionella other than the 25 reference species used in this study.

Bacteriological Techniques↗

PubMed1992

Effect of increasing heart rate on Doppler indices of left ventricular performance in healthy men.

OBJECTIVE: To investigate the effects of heart rate on the Doppler measurements of left ventricular function and to determine the normal pattern of rate dependency. SETTING: University hospital specialising in internal medicine. PARTICIPANTS: 14 healthy male volunteers 10 of whom were studied. INTERVENTION: Transoesophageal atrial pacing. MAIN OUTCOME MEASURES: At paced rates of 70, 80, and 90 ppm the ratio of early to late peak transmitral flow velocity (E/A) was 1.97 (0.28), 1.49 (0.21), and 0.95 (0.11) respectively; the ratio of early to late time-velocity integrals of transmitral flow (Ei/Ai) was 3.03 (0.51), 2.11 (0.24), and 1.14 (0.30) respectively; and the atrial filling fraction (AFF) was 0.17 (0.03), 0.21, (0.04), and 0.24 (0.04) (mean (SD)). RESULTS: Heart rate showed a linear correlation with E/A (r2 = 0.806), Ei/Ai (r2 = 0.838), and AFF (r2 = 0.343). Neither the peak aortic flow velocity or the mean aortic flow acceleration showed significant changes during pacing at rates of 70, 80, 90, and 100 ppm. CONCLUSIONS: E/A and Ei/Ai can be expected to decrease by 0.5 and 0.9 for each increase of 10 beats/min in heart rate. Knowledge of this relation may be useful for the development of algorithms to correct for heart rate when diastolic function is assessed.

Adult↗

PubMed1992

Precocious cessation of intestinal macromolecular transport by synthetic trypsin inhibitor in suckling rats.

The effects of repeated oral administration of the synthetic trypsin inhibitor camostat on intestinal macromolecular transport and disaccharidase development were investigated in suckling rats. By daily treatment with camostat, bovine immunoglobulin (Ig) G transport in the intestine declined more rapidly in treated than in control rats. The absorption curve shifted to the left in treated rats 3 days before the controls. Morphological inspection of treated pups showed a decline in the number of epithelial cells that absorb bovine IgG and in their vesicle size from basal to upper regions of the villi. Maltase activity precociously increased with camostat treatment. Chronic subcutaneous injection of camostat did not cause any changes in IgG transport and maltase activity. The depression of IgG transport by oral treatment with camostat was not affected by the cholecystokinin (CCK) receptor antagonist L 364718 and was not inhibited by adrenalectomy. The absorptive responses of IgG and maltase activity were not affected by CCK-8 treatment. These data indicate that oral administration of camostat induces precocious maturation of the small intestine and that the effect is not mediated via endogenous CCK released by camostat.

Administration, Oral↗

PubMed1992

An immunoelectron-microscopical observation of mouse juxtaglomerular cells in the case of experimental hydronephrosis.

Changes in juxtaglomerular (JG; renin-containing) cells in experimental hydronephrosis 1 month after ureteral ligation were investigated with immunoelectron-microscopical techniques. Two types of granules, electron dense (D) and lucent (L), were observed. D type granules were labeled more intensely with gold particles than those of L type. Granules intermediate between D and L types and exocytosis of D types were observed. In the cells containing D types exclusively, gold particles were restricted to the granules, whereas in the cells containing both D and L type granules, the particles were scattered throughout the cytoplasmic cytosol. The authors discuss the mechanisms of renin release in JG cells.

Animals↗