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M Nishihara

Publications and source records attributed to M Nishihara.

At least 163 records · Page 9Linked to original sources
PubMed1990

Duration and frequency of multiunit electrical activity associated with the hypothalamic gonadotropin releasing hormone pulse generator in the rhesus monkey: differential effects of morphine.

The effects of morphine on the frequency and duration of the characteristic bursts or 'volleys' of multiunit electrical activity (MUA) associated with pulsatile pituitary luteinizing hormone (LH) secretion were studied in unanesthetized ovariectomized rhesus monkeys bearing bilateral arrays of electrodes implanted in the mediobasal hypothalamus. Morphine administration resulted in a dose-dependent decrease in MUA volley duration and frequency. When morphine was infused at 10 micrograms/kg/h, the inhibiting effect on volley duration was observed without a change in volley frequency. It is concluded that the frequency and duration of hypothalamic MUA volleys associated with pulsatile LH secretion may be independently regulated.

Animals↗
PubMed1990

[A case of mediastinal schwannoma originating from the thoracic vagal nerve complicated by early stomach cancer].

Most of primary tumors of the nerves arising in the mediastinum originate from the sympathetic or intercostal nerves. Schwannoma developing from the vagal nerve is very rare. The patient was a 73-year-old male referred to us with abnormal chest X-rays and stomach cancer. One-staged operation was performed by thoracic and upper abdominal median incision. The tumor was removed, which measured 6 X 5 X 4 cm and involved the origin of the left recurrent nerve, by neurectomy. To our knowledge, this was the 18th reported case of schwannoma of the intrathoracic vagal nerve in Japan. A similar schwannoma was observed also in the celiac plexus, and this case was also a rare instance of multiple schwannoma.

Aged↗
PubMed1990

[The therapeutic effect of norfloxacin on chronic prostatitis].

The clinical efficacy of norfloxacin (NFLX) was evaluated on 40 patients. They had subjective symptoms suggestive of prostate inflammations and more than five white blood cells (WBC)/hpf in their prostatic secretions (EPS) or VB3. Of these, gram negative rods were isolated from the EPS in 3 patients and gram positive cocci were obtained in 26 patients. The overall clinical efficacy was determined at the second week. The effectiveness rate of the subjective symptoms was 82.5%. The effectiveness rate of the WBC in the EPS was 47.4%. The effectiveness rate of the bacteria in the EPS was 64.3%. The overall clinical effectiveness rate was 77.8%. A subjective side effect was observed only in one patient who had skin eruption like urticaria. Mild liver dysfunction of blood chemistry analysis was shown only in two patients but they had had long standing chronic hepatitis. We conclude that NFLX is an effective drug for the patients with chronic prostatitis.

Adult↗
PubMed1989

Postsynaptic effects of prolactin and estrogen on arcuate neurons in rat hypothalamic slices.

The effects of 17 beta-estradiol (E2) and prolactin (PRL) on the excitability of neurons in the arcuate nucleus were examined using hypothalamic slices obtained from ovariectomized rats. Neither E2 nor PRL affected the excitability of neurons having antidromic responses due to median eminence stimulation. On the other hand, E2 and PRL altered the spontaneous activity of unidentified neurons, which were not activated by median eminence stimulation, by 6 and 11%, respectively. Both excitatory and inhibitory responses were recorded, which were not abolished in the low Ca2+/high Mg2+ medium. These results suggest that E2 and PRL can rapidly modulate the excitability of some arcuate, but presumably not tuberoinfundibular, neurons by acting directly on the postsynaptic membrane.

Animals↗
PubMed1989

[Clinical evaluation of Parkinson's disease using 123I-IMP SPECT].

N-isopropyl-p[123I]iodoamphetamine (123I-IMP) SPECT and regional cerebral blood flow (rCBF) studies were performed in 20 patients with Parkinson's disease (PD) and 8 normal subjects. RCBF was measured by the arterial blood sampling method which used the microsphere model. We analyzed seven factors which might be related to the rCBF in PD, i.e., age, stage, duration of the disease, cerebral atrophy, severity of dementia, laterality of symptoms and motor disability score (MDS; the degree of akinesia, rigidity, tremor, gait disturbance, freezing and pulsion sign). Compared with normal subjects, global CBF (supratentorial mean rCBF) was reduced 21.8% in PD. In particular, rCBF in the basal ganglia and that of frontal cortex were reduced 25.3%, 24.8%, respectively. Distribution patterns of rCBF in PD were almost as same as those in normals except for cerebellum. The reduction of both rCBFs in the basal ganglia and parietal cortex significantly correlated with MDS (p less than 0.05, respectively). Especially, akinesia was closely correlated to the reduction of rCBF in the parietal cortex (p less than 0.02). Moreover, we observed a significant relationship between cerebral atrophy and reduction of rCBF in each region except for cerebellum. However, there was no significant correlation between the severity of dementia and reduction of rCBF, even in the frontal cortex or parietal cortex. These data show that the severity of dementia in PD may be connected with other factors except for rCBF. 123I-IMP SPECT study is a useful method for clinical evaluation of PD.

Aged↗
PubMed1989

[A clinical study of prostatic carcinoma].

Seventy seven patients with prostatic carcinoma were treated in our clinic between 1977 and 1986. Most of them were treated by a hormonal agent as the first therapy. None of the 9 stage A1 cases showed any reactivation, but 4 of the 5 stage A2 cases relapsed to metastatic disease. The chemotherapy performed in 3 of the 4 reactivated cases had no obvious effect on the disease. Seven of the 8 patients with stage B disease were alive without relapse. Relapse was seen in the other patient who had poorly differentiated carcinoma and chemotherapy in this case resulted in stable disease for the present. Four of the 15 stage C cases including 3 poorly differentiated carcinomas were hormone resistant or reactivated. For these resistant cases radiotherapy and/or the chemotherapy were performed, but a response was seen in only one case. Consequently, the first therapy for stage A2, B and C of poorly differentiated carcinoma must be improved. Of the 40 stage D cases, 4 patients who were treated by an early combination of hormonal therapy and chemotherapy had a better prognosis than the others. These 4 patients had poorly differentiated carcinomas with multiple bone metastases. Two of these 4 patients were alive without relapse for 17 and 72 months, and one of the 2 patients with relapse was also alive for 75 months. We believe that early chemotherapy is the key for better prognosis in stage D cases.

Androgen Antagonists↗
PubMed1988

Hormonal regulation of rat Leydig cell cytochrome P-45017 alpha mRNA levels and characterization of a partial length rat P-45017 alpha cDNA.

We have isolated and characterized a P-45017 alpha cDNA fragment from a rat testis library. The partial length rat P-45017 alpha cDNA (1Kb) has high overall nucleotide and deduced amino acid similarity with human and bovine P-45017 alpha cDNA's and contains the conserved tridecapeptide and heme regions, the termination codon and polyadenylation site. Using this rat testis cDNA probe we measured P-45017 alpha mRNA levels of rat Leydig cells from animals treated with hCG. Temporal studies with a low hCG dose showed an early increase in mRNA levels returning to control values at later times, while a higher desensitizing dose caused a marked reduction in the mRNA (24 h) and a small recovery at 48 h. Fetal rat Leydig cells maintained in the presence of LH treated with estradiol showed a 70% decrease in P-45017 alpha mRNA levels and testosterone production followed closely the changes in P-45017 alpha mRNA. These studies suggest that gonadotropin stimulation and desensitization of P-45017 alpha dependent enzymes in the adult rat testis as well as estradiol induced desensitization in fetal Leydig cells are related to levels P-45017 alpha mRNA.

Amino Acid Sequence↗
PubMed1988

Quantitative conversion of diether or tetraether phospholipids to glycerophosphoesters by dealkylation with boron trichloride: a tool for structural analysis of archaebacterial lipids.

A method for preparing glycerophosphoesters from ether phospholipids by dealkylation with boron trichloride (BCl3) is described. Treatment of ether phospholipids in chloroform with BCl3 for 30 min at room temperature yielded almost quantitatively the corresponding glycerophosphoesters retaining the intact polar head group of the ether phospholipids. Thus, glycerophosphocholine, glycerophosphoinositol, glycerophosphoglycerol, glycerophosphoserine, glycerophosphate, and glycerophosphoethanolamine were prepared from the diether analogs of phosphatidylcholine, phosphatidylinositol, phosphatidylglycerol, phosphatidylserine, and phosphatidic acid, and the tetraether analog of phosphatidylethanolamine, respectively. BCl3 also cleaved diacyl, alkyl-acyl, and alk-1-enyl-acyl forms of phospholipids to yield corresponding glycerophosphoesters. The glycerophosphoesters were separated more rapidly by cellulose thin-layer chromatography with the same solvent system as in paper chromatography. This method is of great use for structure determination of glycerophosphoester backbones of ether phospholipids, analogous to the mild alkaline methanolysis of diacyl form of phospholipids, as well as for the analysis of alkyl chains. It is, however, not applicable to glycolipids because of cleavage of glycosidic bonds by BCl3.

Archaea↗
PubMed1988

[A clinical study of 33 cases of renal pelvic and ureteral tumors].

Thirty-three cases of primary renal pelvic and/or ureteral tumors, i.e., 14 renal pelvic tumors, 14 ureteral tumors and 5 renal pelvic and ureteral tumors, treated at our hospital between November, 1976 and August, 1987 are reviewed retrospectively. Tumor occurred on the right side in 18 cases, left side in 14 cases and bilateral in one case. The patients ranged in age from 33 to 77 years (average 65.7 years), the sex ratio was 4.5:1 with male predominance over female. The most frequent symptoms were gross hematuria in 22 cases (67%). Interval from onset of initial symptoms to first visit within one month for 23 cases (70%). The major findings of excretory urograms were non-visualizing kidney in 18 cases (55%) and filling defect in 12 cases (36%). Positive urinary cytology was obtained in 18 cases (55%). Operative therapy was performed in all cases, namely, total nephroureterectomy with partial cystectomy in 21 cases (64%) and nephrectomy with transurethral ureterectomy in 7 cases (21%). Histopathologically, all cases but one case of squamous cell carcinoma were transitional cell carcinoma. Subsequent bladder tumors were found in 10 cases (30%). The overall survival rate at 1, 3 and 5 years were 84%, 68% and 61%, respectively by Kaplan-Meier method. In this series, grade and stage of tumor were the most influential factors for prognosis.

Adult↗
PubMed1987

Structure determination of a quartet of novel tetraether lipids from Methanobacterium thermoautotrophicum.

The structures of three of the major polar lipids (PNL1a, GL1a, and PNGL1) of Methanobacterium thermoautotrophicum were elucidated. These lipids are derivatives of dibiphytanyl diglycerol tetraether (C40 tetraether; the proposed name is caldarchaeol). PNL1a is a C40 tetraether analog of phosphatidylethanolamine (proposed name: caldarchaetidylethanolamine). GL1a was identified as beta-D-glucopyranosyl-(1-6)-beta-D-glucopyranosyl C40 tetraether (diglucosyl caldarchaeol). PNGL1 has the polar head groups of both PNL1a and GL1a; one of the free hydroxyls of this tetraether is esterified with phosphoethanolamine while the other is linked to a glucosylglucose residue with the same structure as that of GL1a (proposed name: diglucosyl caldarchaetidylethanolamine). That is, PNL1a (aminophospholipid), GL1a (glycolipid), and PNGL1 (aminophosphoglycolipid) form structurally a quartet of lipids with the bare caldarchaeol. We propose a new systematic nomenclature of archaebacterial polar lipids in the "DISCUSSION," because the alternative names are too lengthy and laboratory designations of these lipids are not at all systematic. This nomenclature starts with giving the names archaeol and caldarchaeol to dialkyl diether of glycerol or other polyol and tetraether of glycerol or other polyol and alkyl alcohols, respectively, because these lipids are specific to archaebacteria. Phospholipids with a phosphodiester bond were named as derivatives of archaetidic acid or caldarchaetidic acid (phosphomonoesters of archaeol and caldarchaeol) by analogy with phosphatidic acid.

Ethanolamine↗
PubMed1987

Extraction and composition of polar lipids from the archaebacterium, Methanobacterium thermoautotrophicum: effective extraction of tetraether lipids by an acidified solvent.

The usual Bligh and Dyer method could extract only a small part of the lipids of Methanobacterium thermoautotrophicum. When the water in the solvent was replaced by 5% trichloroacetic acid, the lipid recovery reached the maximum level, which was 6 times higher than that by the former method. The use of HCl (2 M) or disruption of cells was also effective but prolonged extraction with the HCl-containing solvent caused degradation of some phosphoglycolipids. Twenty-three spots of polar lipids were detected on a thin-layer chromatogram of the total lipid. These were 10 phospholipids (18%), 6 aminophospholipids (17%), 3 aminophosphoglycolipids (15%), 2 phosphoglycolipids (31%), and 2 glycolipids (19%). The predominant polar lipids were a highly polar phosphoglycolipid (PGL1, 30%) and a glycolipid (GL1a, 16%). The other major lipids included an aminophospholipid (PNL1a, 9%), and an aminophosphoglycolipid (PNGL1, 7%). The complete structure determination of PNL1a, GL1a, and PNGL1 is described in the accompanying paper. Acetolysis of the total lipids followed by acid methanolysis was required for the complete cleavage of polar head groups, releasing core residues of diphytanyl glycerol diether (C20 diether) and dibiphytanyl diglycerol tetraether (C40 tetraether). A densitometric assay of a thin-layer chromatogram showed that the ratio of C20 diether and C40 tetraether was 1:14. GLC analysis of alkyl chlorides prepared from the total lipid by BCl3 treatment showed that phytanyl (C20), biphytanyl (C40), and unidentified alkyl chains accounted for 10, 83, and 7 mol% of the total alkyl chains, respectively. Strong acid hydrolysis of the macromolecular residue obtained after lipid extraction gave a significant amount of C40 tetraether, which had probably been bound covalently to other substances in the cells.

Ethers↗
PubMed1987

Roles of gamma-aminobutyric acid and serotonin in the arcuate nucleus in the control of prolactin and luteinizing hormone secretion.

The effects of implantation of gamma-aminobutyric acid (GABA) and serotonin (5-HT) into the arcuate nucleus (ARC) on serum luteinizing hormone (LH) and prolactin (PRL) were examined in the conscious ovariectomized rat. Following implantation of 5-HT, but not GABA, serum PRL was significantly increased. While 5-HT did not affect pulsatile LH secretion, GABA significantly decreased the mean LH concentration and pulse frequency, but not amplitude.

Animals↗