Search PubMed⌕ Search

Biomedical subjects

Y Murakami

Publications and source records attributed to Y Murakami.

At least 919 records · Page 51Linked to original sources
PubMed1985

Purification and characterization of endo-beta-N-acetylglucosaminidase of Aspergillus oryzae.

An endo-beta-N-acetylglucosaminidase which hydrolyzes the N,N'-diacetylchitobiosyl linkage in asparagine-linked oligosaccharides was purified from the enzyme product of Aspergillus oryzae. Its substrate specificity was similar to that of endo-beta-N-acetylglucosaminidase H from Streptomyces griseus with respect to the relative activities toward the glycopeptides obtained from ovalbumin and bovine IgG. The present endoglycosidase exhibited a broad optimum pH range and was relatively stable. Metal ions, chelating agents and D-mannose did not have a significant effect on the enzyme activity.

Acetylglucosaminidase↗
PubMed1985

Appearance of dark keratinocytes following intracutaneous injection of cholera toxin in mouse skin.

Intracutaneous injection of cholera toxin (CT), exotoxin of Vibrio cholerae, induces epidermal hyperplasia in mice, rats, and hamsters. In the work reported here we found that, like other hyperplasiogenic compounds such as 12-O-tetradecanoylphorbol-13-acetate which are tumor promoters, CT induces dark basal keratinocytes (dark cells) in the epidermis of mice. These are distinct from other epidermal cells since they contain dense cytoplasm rich in ribosomes and tonofilaments. This was demonstrated by electron microscopy and by toluidine blue staining of paraffin- or Epon-embedded sections. They comprised 3.1% of interfollicular basal cells 24-64 h after injection of 1 ng CT as compared with 0.5% in saline-injected skin. It was found by autoradiography of paraffin sections that about 47.2% of dark cells were labeled with [3H]thymidine at these times, while under the same conditions, labeling indices of basal cells were about 30% at the peaks. These results are discussed in relation to tumor promotion in two-stage carcinogenesis of mouse skin.

Animals↗
PubMed1985

Novel dnaG mutation in a dnaP mutant of Escherichia coli.

Reexamination of the dnaP18 mutant strain of Escherichia coli revealed that the mutation responsible for the arrest of DNA replication and cell growth at high temperatures resides in the dnaG gene rather than in the dnaP locus as previously thought; this mutation has been designated dnaG2903.

Bacterial Proteins↗
PubMed1985

Involvement of growth hormone-releasing factor in growth hormone secretion induced by gamma-aminobutyric acid in conscious rats.

Intracerebroventricular (icv) injection of gamma-aminobutyric acid (GABA) (10 mumol/rat) resulted in an increase in plasma GH in conscious freely moving rats pretreated with normal rabbit serum (0.5 ml/rat, iv). Rabbit antiserum specific for rat GH-releasing factor (GRF) (0.5 ml/rat, iv) abolished GH release induced by GABA in these animals. Rabbit anti-rat GRF serum also blunted GH release induced by a Met5-enkephalin analog, FK33-824 (10 micrograms/100 g BW, iv) in conscious rats. Considering our previous findings that rat GH release induced by FK33-824 was blunted by GABA antagonists (Endocrinology 103:1033, 1981), these results suggest that GH secretion induced by opioid peptides via GABAergic mechanisms is mediated, at least in part, by hypothalamic GRF in the rat.

Animals↗
PubMed1985

Isolation and initial characterization of a temperature-sensitive mutant of mouse FM3A cells defective in cytokinesis.

A temperature-sensitive mutant, designated tsFT101, was isolated from a mouse mammary carcinoma cell line, FM3A, and given an initial characterization. In this cell line, cytokinesis was blocked at a non-permissive temperature (39 degrees C), but DNA synthesis and nuclear division proceeded normally for at least 24 h at 39 degrees C as detected respectively by autoradiography and cytofluorometric analysis. As a result, multinucleate cells accumulated at 39 degrees C (more than 95% in 36 h). When the culture was returned to a permissive temperature (33 degrees C) after 24 h of arrest at 39 degrees C, cytokinesis was resumed and there was a rapid decrease in the number of multinucleate cells. At 39 degrees C, tsFT101 cells had less F-actin than cells at 33 degrees C, indicative of the existence of an abnormality in actin polymerization in this mutant.

Actins↗
PubMed1985

Inhibition by antiserum to rat growth hormone-releasing factor of growth hormone secretion induced by a met5-enkephalin analog, FK33-824, in rats.

A Met5-enkephalin analog, FK33-824 (5, 10 and 20 micrograms/100 g body wt, iv) caused a dose-related increase in plasma growth hormone (GH) in urethane-anesthetized male rats. Pretreatment with cysteamine (30 mg/100 g body wt, sc), a depletor of hypothalamic somatostatin, increased the plasma GH response to FK33-824 (10 micrograms/100 g body wt, iv). Antiserum specific for rat GH-releasing factor (GRF) (0.5 ml/rat, iv) blunted GH release induced by FK33-824 (10 micrograms/100 g body wt, iv) in rats with or without cysteamine pretreatment. These results suggest that GH secretion induced by the opioid peptide is mediated, at least in part, by hypothalamic GRF in the rat.

Animals↗
PubMed1985

Involvement of peptide histidine isoleucine (PHI) in prolactin secretion induced by serotonin in rats.

The possible role of hypothalamic peptide histidine isoleucine (PHI) in prolactin (PRL) secretion induced by serotoninergic mechanisms was investigated in male rats using a passive immunization technique. Intracerebroventricular injection of serotonin (5HT, 10 micrograms/rat) raised plasma PRL levels both in urethane-anesthetized rats and in conscious rats pretreated with normal rabbit serum (0.5 ml/rat, iv, 30 min before). Plasma PRL responses to 5HT were blunted in these animals when they were pretreated with rabbit antiserum specific for PHI (0.5 ml/rat, iv, 30 min before) (mean +/- SE peak plasma PRL: anesthetized rats 271.3 +/- 38.3 ng/ml vs 150.0 +/- 12.6 ng/ml, p less than 0.01, conscious rats 54.3 +/- 6.8 ng/ml vs 30.7 +/- 4.1 ng/ml, p less than 0.025). These results suggest that hypothalamic PHI is involved, at least in part, in PRL secretion induced by central serotoninergic stimulation in the rat.

Animals↗
PubMed1985

[Combined chemotherapy for head and neck cancer using cisplatin, methotrexate and continuous subcutaneous infusion of peplomycin].

Twenty-one patients with advanced or recurrent squamous cell carcinoma of the head and neck were treated with cisplatin, methotrexate and continuous subcutaneous infusion of peplomycin. The overall response rate was 62% (13/21) with 19% (4/21) complete response. The median duration of partial response was 2 months, while that of complete response was 3 months. Toxic effects were acceptable with no fatalities, but nephrotoxicity (33%), leukocytopenia (24%), thrombocytopenia (29%) and severe nausea and vomiting (76%) occurred. Pulmonary toxicity due to continuous subcutaneous infusion of peplomycin (15 mg/day, 4 days) was not seen.

Adult↗
PubMed1985

[Human science].

Explore the source record for details and available documents.

Dentistry↗
PubMed1985

[CT-guided stereotactic neurosurgery].

Brown-Roberts-Wells stereotactic instruments were used for CT guided stereotactic surgery in 54 cases (65 operations). Stereotactic biopsy was done in 9 cases and successive regional chemotherapy was done in 3 cases. Stereotactic drainage was done in 2 cases of bacterial abscess, 3 cases of cystic neoplasm and 33 cases (43 operations) of intracerebral hematoma. CT guided stereotactic procedure was valuable for the correct cannulation to the center of the cavity. We tried to utilize CT image for the selection of targets for stereotactic functional neurosurgical procedures in 6 cases. In the cases of thalamotomy, the information derived from CT made the operation safer than that by contrast ventriculography alone. In all cases of electrode implantation for deep brain stimulation, accurate and precise electrode placement was achieved from CT images alone. This rapid and easy surgical technique was useful also for poor risk patients.

Astrocytoma↗
PubMed1985

[A case report of cystadenocarcinoma of the liver].

A 65-year-old woman with cystadenocarcinoma of the liver is reported, and 21 Japanese patients cited in the previous literature are reviewed. In our case, CT and US demonstrated a huge solid tumor with calcification in the right lobe of the liver. Angiograms showed a hypovascular tumor with peripheral irregular neovascularity. ERCP showed compression of the extrahepatic bile duct. Right lobectomy of the liver was performed. The pathological diagnosis was cystadenocarcinoma of the liver. In our case, it was difficult to diagnose cystadenocarcinoma because the cystic mass had viscious contents and necrotic tissues, so CT and US showed findings of a solid tumor.

Angiography↗
PubMed1985

[A case of sigmoid-vesical fistula complicating diverticulitis of the colon].

The clinical course of sigmoidvesical fistula due to rupture of colonic diverticulitis is described. The patient, a 72-year-old-man, had chief complaints of cloudy urine, pneumaturia and fecaluria. The fistula was diagnosed by cystoscopy. In this case, primary resection of the sigmoid colon and wedge resection of the bladder including fistula were performed, and the sigmoidvesical fistula was completely cured. Statistical analysis was made on 43 cases of colovesical fistula due to diverticulitis in Japan including our own case.

Aged↗
PubMed1984

Antizyme to ornithine decarboxylase is present in the liver of starved rats.

Antizyme to ornithine decarboxylase (ODC) and ODC-antizyme complex were both present in liver cytosols of starved rats. The antizyme was identified by its molecular weight, kinetic properties, formation of a complex with ODC, and reversal of its inhibition by antizyme inhibitor. The average amount of antizyme in liver cytosols of starved rats was 0.1 unit/mg of protein, roughly corresponding to basal hepatic ODC activity in rats fed ad libitum. The presence of ODC-antizyme complex was detected by using antizyme inhibitor. These results indicate that antizyme participates in the regulation of ODC activity in vivo under physiological conditions.

Animals↗