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Biomedical subjects

K Hirota

Publications and source records attributed to K Hirota.

At least 271 records · Page 15Linked to original sources
PubMed1995

An investigation of gram-negative tannin-protein complex degrading bacteria in fecal flora of various mammals.

Gram-negative tannin-protein complex degrading bacteria (T-PCDB) were first isolated from animals except for the koala. The occurrence of T-PCDB in feces of 15 species of mammals with different feeding habits was investigated. T-PCDB occurred in 7 of 54 horses but they could not be isolated from other mammals tested. These T-PCDB comprised less than 0.1% of the facultative anaerobic microflora in horse feces and it was much less than that previously reported in koala feces ( > 60%). A total of 7 T-PCDB fecal isolates showed a range of phenotypic diversities. They were all Gram-negative rods of various sizes and shapes including coccoidal rod. Although all produced tannase, no strain showed to have gallate decarboxylase. A total of 23 representative strains belonging to the family Pasteurellaceae were also tested for tannase production. Two strains, Haemophilus actinomycetemcomitans NIAH-10202T and Haemophilus segnis NIAH-10183T which were isolated from human oral cavity were detected positive for tannase.

Animals↗
PubMed1995

[Does aging influence effect of pirenzepine alone or combination of pirenzepine and famotidine on gastric secretion during anesthesia and surgery?].

Effect of pirenzepine alone or the combination of pirenzepine and famotidine on gastric secretion during anesthesia and surgery was evaluated in 52 elective surgical patients ranged in age from 17 to 68 years. These patients of each group were divided into two subgroups according to their age either 40 years and under or over. The patients underwent orthopedic, ophthalmic, ENT, plastic or non-abdominal general surgery under neuroleptanesthesia except 5 patients who had enflurane or isoflurane anesthesia. They received either pirenzepine 10 mg or the combination of pirenzepine 10 mg and famotidine 20 mg intravenously just before the induction of anesthesia. Volume and acidity of gastric juice were measured for 3 hours after the administration of these agents. Decrease in volume and acidity of gastric juice continued for more than 3 hours after the administration of pirenzepine alone or the combination of pirenzepine and famotidine, and it was more prominent in the combination group than in the pirenzepine group. There was no statistical difference in volume of gastric juice between the patients of 40 years and under in age and those over 40 years in each group. However, the intragastric pH tended to be lower in patients of 40 years and under in age than that in those over 40 years. A percentage of patients who had intragastric pH below 2.5 was larger in the pirenzepine administered patients of 40 years and under in age than that of the remaining patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1995

[Anesthesia for SUMO wrestlers].

We anesthetized 34 sumo wrestlers. All patients were male. Average age was 21.1. Their height was 181.9 +/- 4.5 (mean +/- SD) cm, and they weighted 135.2 +/- 16.9 kg. Anesthetic methods used were spinal anesthesia alone in 17 patients, general anesthesia alone in 9, general anesthesia + epidural anesthesia/or spinal anesthesia/or axillary block in 8. The preoperative data showed findings common to obese patients; liver dysfunction, abnormal blood sugar, and abnormal ECG such as ST depression or left ventricular hypertrophy. For intubation, fiberscopy was required in one patient, and almost all patients required high FIO2, otherwise SaO2 decreased. For spinal anesthesia or epidural anesthesia, we needed long needles of 8 to 15 cm.

Adult↗
PubMed1995

Substitution effect of purine nucleosides on diisobutylaluminum hybride reduction.

It is reported that the diisobutylaluminum hydride (DIBALH) reduction of inosine and adenosine derivatives (1a and 1d) causes cleavage of the ribose moiety to give the corresponding 9-ribitylhypoxanthine (2a) and 9-ribityladenine (2d), respectively. The substitution effect of purine nucleosides on the reduction was investigated. O6-alkylinosine derivatives (1b and 1c) were reduced in good yields like 1a. Introduction of methyl group into the N6-position of adenosine (1d), however, greatly reduced the reactivity toward DIBALH. The reduction of 7-deazainosine (3a) and 7-deazaadenosine (3b) hardly proceeded. These results suggest that oxygenophilicity of aluminum atom facilitates coordination of DIBALH to the 7-ring nitrogen atom and accelerate a cleavage of the ribose.

Binding Sites↗
PubMed1994

In vitro effects of CINC/gro, a member of the interleukin-8 family, on hormone secretion by rat anterior pituitary cells.

We investigated the effects of CINC/gro on hormone secretion using normal rat anterior pituitary cells. In normal anterior pituitary cells, 10-100 ng/ml of CINC/gro significantly increased the secretion of PRL within 3 h of incubation, and two-fold enhancement of PRL secretion was induced by 100 ng/ml of CINC/gro within 24-h incubation, while the response of GH and ACTH secretions to CINC/gro was weak. On the other hand, CINC/gro suppressed basal LH and FSH secretions in a concentration-dependent manner. The percent inhibition of basal secretion by CINC/gro (50 ng/ml) within 24-h incubation was 70% for LH and 43% for FSH. Twenty-four-hour incubation with 100 ng/ml of IAP completely blocked the CINC/gro-stimulated PRL and GH secretions and CINC/gro's suppression of both basal LH and FSH secretions. These data demonstrate a new biological activity for CINC/gro and provide evidence for immune system regulation of anterior pituitary hormone secretion.

Analysis of Variance↗
PubMed1994

The production of CINC/gro, a member of the interleukin-8 family, in rat anterior pituitary gland.

We investigated the possibility of detection of CINC/gro, which is a IL-8-like neutrophil chemoattractant, immunoreactivity in rat normal anterior pituitary gland by immunohistochemistry, western blot analysis and an ELISA. We first ascertained the possibility of detection of CINC/gro immunoreactivity in the anterior pituitary gland by immunocytochemistry. In the anterior lobe of the pituitary gland, a few CINC/gro-like immunoreactive cells were observed (1-3% of all cells in the anterior pituitary). The positive cells were middle or large in size and looked angular in shape. Intense immunoreactivity was observed in the cytoplasm but not in the nucleus. Analysis by immunoblotting with anti-CINC/gro antiserum gave a characteristic single CINC/gro band with a molecular weight of 6.3 kDa. CINC/gro immunoreactivity was also detected in 3-h conditioned medium of normal anterior pituitary cells by an ELISA, and that immunoreactivity increased significantly in a time-dependent manner during 24-h incubation. This immunoreactivity could be induced by TNF-alpha in a dose-dependent manner. These findings indicate that CINC/gro is produced in pituitary gland and also suggests the possibility that CINC/gro may play some role asa modulator of anterior pituitary function, especially in the cross-talk mechanism between the immune and neuroendocrine systems.

Analysis of Variance↗
PubMed1994

Dopamine inhibits TRH-induced MAP kinase activation in dispersed rat anterior pituitary cells.

We recently reported the existence of two separate pathways for thyrotropin-releasing hormone (TRH)-induced mitogen-activated protein (MAP) kinase activation in GH3 pituitary tumor cells. To test the role of MAP kinase in TRH action, we examined the effect of dopamine (DA) on TRH-induced MAP kinase in primary cultures of rat anterior pituitary cells. 1 microM of DA attenuated 1 microM TRH-induced MAP kinase activity and phosphorylation. 100 ng/ml of islet-activating protein (IAP) blocked these inhibitory effects of DA. These results suggest that crosstalk exists between the DA signaling pathway and the TRH-stimulated MAP kinase activating pathway in rat anterior pituitary cells.

Adenosine Triphosphate↗
PubMed1994

In vitro effects of CINC/gro, a member of the interleukin-8 family, on interleukin-6 secretion by rat posterior pituitary cells.

We investigated the effects of CINC/gro on IL-6 secretion by rat posterior pituitary cells. CINC/gro immunoreactivity was already detected in 1-h conditioned medium of normal posterior pituitary cells, and it increased significantly in a time-dependent manner during the first 24 h of culture. This immunoreactivity could be induced by TNF-alpha in a dose-dependent manner. On the other hand, CINC/gro stimulated IL-6 secretion by posterior pituitary monolayer cultures in a concentration dependent manner. Thus, CINC/gro significantly (P < 0.01) increased the secretion of IL-6 within 13 h of incubation, and this effect continued throughout 24 h of incubation. The stimulatory effect of 100 ng/ml CINC/gro on IL-6 secretion was completely blocked by 24-h incubation with 100 ng/ml IAP. These data demonstrate a new biological activity for CINC/gro in the posterior pituitary system.

Animals↗
PubMed1994

A possible involvement of tyrosine kinase in TRH-induced prolactin secretion in GH3 cells.

Thyrotropin-releasing hormone (TRH) is a well-known regulatory factor of prolactin (PRL) secretion and synthesis in lactotrophs. Recently we have found that TRH stimulates early tyrosine phosphorylation of MAP kinase in GH3 cells. Then we investigated whether tyrosine phosphorylation in TRH action is involved in TRH-stimulated PRL secretion by GH3 cells, using a 4-hydroxycinnamamide derivative (ST638), a tyrosine kinase inhibitor. TRH-stimulated tyrosine phosphorylation of MAP kinase and PRL secretion were remarkably inhibited by ST638 treatment. These results suggest that tyrosine phosphorylation of MAP kinase is strongly associated with TRH-stimulated PRL secretion.

Animals↗
PubMed1994

Thyrotropin-releasing hormone stimulates MAP kinase activity in GH3 cells by divergent pathways. Evidence of a role for early tyrosine phosphorylation.

Regulation of the mitogen-activated protein (MAP) kinase by thyrotropin-releasing hormone (TRH) in GH3 rat pituitary tumor cells was investigated. Both TRH and epidermal growth factor (EGF) acutely activated this enzyme, via tyrosine and serine/threonine phosphorylation. Down-regulation of cellular protein kinase C (PKC) only partly inhibited the phosphorylation of MAP kinase by TRH, suggesting both PKC-dependent and -independent pathways. Both TRH and EGF similarly increased the phosphorylation of raf-1, by a PKC-independent mechanism. Both TRH and EGF stimulated the formation of a ras-GTP complex. This activation of ras by growth factors is thought to involve the tyrosine phosphorylation of Shc. EGF stimulated the tyrosine phosphorylation of three Shc proteins and their subsequent association with its receptor. TRH stimulated the tyrosine phosphorylation of the 52-kDa Shc protein, although neither phorbol esters nor the calcium ionophore A23187 had any effect, indicating that this effect of TRH was not dependent on PKC. Both TRH and EGF induced the association of tyrosine phosphorylated Shc proteins with a fusion protein containing SH2 and SH3 domains of Grb2, another important component in ras activation. These results provide evidence that MAP kinase is acutely activated by TRH through a PKC-dependent pathway as well as a second pathway possibly involving tyrosine phosphorylation.

Adaptor Proteins, Signal Transducing↗