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Biomedical subjects

T Murai

Publications and source records attributed to T Murai.

At least 145 records · Page 8Linked to original sources
PubMed1996

Functional psychosis mimicking acute confusional state: longitudinal neuropsychological assessment of an acute and transient psychotic patient.

One patient with acute and transient functional psychosis was assessed repeatedly using a brief neuropsychological assessment during his recovery from the psychotic episode. The psychotic features of the patient were characterized by perplexed behavior, attentional disturbance and emotional turmoil. Characteristic findings, including impairment of attention tests, dysgraphia and constructional disturbances, were seen. Findings improved in accordance with recovery on a behavioral level. We discussed the similarity of neuropsychological and behavioral abnormalities of this patient and those of patients in an acute confusional state.

Acute Disease↗
PubMed1996

Evaluation of ethanol on gastric epithelial restoration in vitro.

Ethanol exerts damaging effects on gastric mucosa and delays ulcer healing. To investigate the effect of ethanol on the wound repairing process, we used a wound repair model using primary cultured gastric mucosal cells. A confluent monolayer gastric mucosal cell sheet consisting mainly of mucous cells was wounded to make a cell-free area of constant size. Cell-free area was restored with time after wounding and monitored every 12 hr using a computer image analyzer to observe epithelial cell restoration quantitatively in the presence and absence of ethanol (2.0%). It was found that, although the control wound was completely repaired in 36 to 48 hr, the group treated with 2.0% ethanol showed a significant delay of repair. In the control, 5-bromodeoxyuridine-positive cells appeared around the wound in 24 to 36 hr. In contrast, the group treated with 2.0% ethanol showed no 5-bromodeoxyuridine-positive cells during the experiment. In conclusion, 2.0% ethanol retarded the repair of gastric mucosal restoration by inhibiting the initial gastric cell migration, followed by inhibition of proliferation of cells.

Animals↗
PubMed1996

Potentiation of lethal endotoxin shock by streptococcal pyrogenic exotoxin in rabbits: possible relevance of hyperreactivity of macrophages to endotoxin.

Streptococcal pyrogenic exotoxin (SPE) potentiates lethal shock induced by endotoxin. We have previously reported that macrophages derived from SPE-treated rabbits showed hyperreactivity to endotoxin, and that the effect of SPE on macrophages was mediated by a lymphokine(s). Here we show that culture supernatants of SPE-stimulated lymphocytes, when administered into rabbits three hours before or together with endotoxin, potentiate a variety of endotoxin-induced pathophysiological changes and even lethal shock. These results suggest that SPE-induced lymphokine(s) mediates the potentiating effect of SPE on the lethal endotoxin shock through enhancing endotoxin reactivity of macrophages which play the central role in mediating endotoxin toxicity.

Animals↗
PubMed1996

Effect of in vitro and in vivo administration of dexamethasone on rat macrophage functions: comparison between alveolar and peritoneal macrophages.

Resident alveolar macrophages (AMs) and peritoneal macrophages (PMs), though they originate from common precursor cells, differ morphologically and functionally. The two types of macrophages residing in different tissues may respond differently to glucocorticoids. In the present study, we compared the effects of a synthetic glucocorticoid, dexamethasone (Dex), on rat AMs and PMs with regard to their phagocytic activity and tumour necrosis factor-alpha (TNF-alpha) releasability. In vitro exposure of the macrophages to Dex caused the depression of phagocytic activity of AMs but not of PMs. In contrast, TNF-alpha releasability was depressed in the both types of macrophages, and no difference was found between AMs and PMs in their susceptibility to TNF-alpha regulation by Dex. When Dex was administered subcutaneously into rats, phagocytic activity was severely depressed in AMs but not in PMs. On the other hand, TNF-alpha releasability was depressed both in AMs and PMs by the in vivo Dex administration. The depression in PMs, however, was transitory and less severe than that in AMs. These results suggest that alveolar macrophages and peritoneal macrophages differ intrinsically in responses to glucocorticoid, and that the cell location and the cell's microenvironment can also modulate the effects of glucocorticoid on macrophage functions.

Administration, Cutaneous↗
PubMed1995

Cancer induction by an organic arsenic compound, dimethylarsinic acid (cacodylic acid), in F344/DuCrj rats after pretreatment with five carcinogens.

Arsenic (As) is environmentally ubiquitous and an epidemiologically significant chemical related to certain human cancers. Dimethylarsinic acid (cacodylic acid; DMA) is one of the major methylated metabolites of ingested arsenicals in most mammals. To evaluate the effects of DMA on chemical carcinogenesis, we conducted a multiorgan bioassay in rats given various doses of DMA. One-hundred twenty-four male F344/DuCrj rats were divided randomly into 7 groups (20 rats each for groups 1-5; 12 rats each for groups 6 and 7). To initiate multiple organs and tissues, animals in groups 1-5 were treated sequentially with diethylnitrosamine (100 mg/kg body weight, i.p., single dose at the commencement) and N-methyl-N-nitrosourea (20 mg/kg body weight, i.p., 4 times, on days 5, 8, 11, and 14). Thereafter, rats received 1,2-dimethylhydrazine (40 mg/kg body weight, s.c., 4 times, on days 18, 22, 26, and 30). During the same period, the animals were sequentially administered N-butyl-N-(4-hydroxybutyl)nitrosamine (0.05% in the drinking water, during weeks 1 and 2) and N-bis(2-hydroxypropyl)nitrosamine (0.1% in the drinking water, during weeks 3 and 4; DMBDD treatment). After a 2-week interval, groups 2-5 were given 50, 100, 200, or 400 ppm DMA, respectively, in the drinking water. Groups 6 and 7, which were not given DMBDD treatment, received 100 and 400 ppm DMA during weeks 6-30. All rats were killed at the end of week 30. In the initiated groups (groups 1-5), DMA significantly enhanced the tumor induction in the urinary bladder, kidney, liver, and thyroid gland, with respective incidences in group 5 (400 ppm DMA) being 80, 65, 65, and 45%. Induction of preneoplastic lesions (glutathione S-transferase placental form-positive foci in the liver and atypical tubules in the kidney) was also significantly increased in DMA-treated groups. Ornithine decarboxylase activity in the kidneys of rats treated with 100 ppm DMA was significantly increased compared with control values (P < 0.001). In conclusion, DMA is acting as a promoter of urinary bladder, kidney, liver, and thyroid gland carcinogenesis in rats, and we speculate that this may be related to cancer induction by As in humans.

Acetyltransferases↗
PubMed1995

Auditory brainstem response findings in brainstem ischemia following selective occlusion of the anterior inferior cerebellar artery in the rat.

Auditory brainstem responses (ABRs) were measured ipsilaterally (n = 13) or contralaterally (n = 5) after inducing permanent right and left anterior inferior cerebellar artery (AICA) occlusion. Three types of wave patterns were classified when ABRs were recorded ipsilaterally. In type 1 (n = 4) all components disappeared; in type 2 (n = 2) all components disappeared transiently and then reappeared; and in type 3 (n = 7) only the latency difference between components I and IV increased. These findings indicate that all components reappeared in type 2 responses because cochlear blood flow was re-established quickly by collateral circulation, while type 3 changes reflected the relative sensitivity of the cochlea to ischemic damage when compared with the rest of the auditory pathways. When the ABRs were recorded contralaterally, characteristic findings included a delay in latency of component IV and a significant increase in inter-peak latency in components I-IV and IIb-IV.

Animals↗
PubMed1995

Validation of silver-stained nucleolar organizer regions for evaluation of invasive character of urinary bladder carcinoma in rats and mice.

A series of 8 rat and 16 mouse invasive bladder carcinomas were investigated for the presence of silver-stained nucleolar organizer regions (AgNORs) to clarify whether this parameter is applicable to the estimation of their invasive character. With regard to number of AgNORs per cell, neither rat nor mouse carcinomas showed any difference between invasive and noninvasive sites within the same tumor. However, the frequency of cancer cells bearing bizarre dots, irregular in size and shape, was significantly higher at sites of actual invasion. Quantitative data generated using an image analyzer revealed significantly lower values for NOR roundness and significantly larger NOR size in invasive sites than in noninvasive sites in all groups. Double staining for the proliferation marker proliferating cell nuclear antigen (PCNA) and AgNORs was performed on eight rat carcinomas and a close correlation between the two was confirmed. Thus the number of AgNORs in PCNA-positive cells was significantly greater than in PCNA-negative cells. Furthermore, a particularly strong correlation was observed for incidences of PCNA-positive cells and bizarre dots (P < 0.01). The quantitative data also demonstrated significant differences in size and shape of dots. It is concluded that AgNORs have diagnostic value for the invasive character of bladder carcinomas.

Animals↗
PubMed1995

Frequent mutations of the p53 gene and infrequent H- and K-ras mutations in urinary bladder carcinomas of NON/Shi mice treated with N-butyl-N-(4-hydroxybutyl)nitrosamine.

To elucidate whether common genetic events in human urinary bladder carcinogenesis also occur in rodent models, we investigated the presence of p53, H- and K-ras mutations in 18 urinary bladder carcinomas induced by various concentrations of N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN) in male NON/Shi mice. Histopathologically, all were invasive, 11 being squamous cell carcinomas (SCCs) and the remaining seven being transitional cell carcinomas (TCCs). Using polymerase chain reaction single-strand conformation polymorphism (PCR-SSCP) analysis followed by DNA sequencing, p53, H- and K-ras mutations were observed in 14 (78%; exons 5-7), two (11%; one each on exons 1 and 2) and one (5.6%; exon 1) animals respectively. The frequencies of mutations in p53 exons 5, 6 and 7 were 7 (39%), 4 (22%), and 9 (50%) respectively, and no mutation was found in exon 8. All mutations involved one base-pair substitution with or without amino acid changes and the types of base-pair substitution were random. No evident association was observed between mutation sites and the histological phenotypes. In conclusion, p53 mutations are frequent in BBN-induced mouse invasive urinary bladder tumors, at similar levels to those observed for human high-grade invasive carcinomas, and this plus their distribution suggests their possible participation in this model of urinary bladder carcinogenesis.

Amino Acid Sequence↗
PubMed1995

Lack of promoting effects of alpha-linolenic, linoleic or palmitic acid on urinary bladder carcinogenesis in rats.

Potential promoting effects of alpha-linolenic, linoleic and palmitic acids were investigated in a two-stage urinary bladder carcinogenesis model. In experiment 1, male F344 rats were given 0.05% N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN) in their drinking water for 4 weeks and then basal diet containing 10% alpha-linolenic, 10% linoleic or 10% palmitic acid along with 0.2% butylated hydroxyanisole (BHA) as an antioxidant for 24 weeks. The development of tumors in the urinary bladder was not increased by treatment with any of the fatty acids. In experiment 2, male F344 rats were given 10% alpha-linolenic, 10% linoleic or 10% palmitic acid along with 0.2% BHA in their diet for 8 weeks without prior BBN treatment. The administration of fatty acids was not associated with any increase in the 5-bromo-2'-deoxyuridine labeling index of the urinary bladder epithelium. Serum and/or urine fatty acid levels increased in the cases of alpha-linolenic and linoleic acid treatments, but not with palmitic acid. Under the present experimental conditions neither the two polyunsaturated nor the one saturated fatty acid exerted any promoting effect on urinary bladder carcinogenesis.

Animals↗
PubMed1995

Thyrotropin-producing pituitary adenoma discovered as a pituitary incidentaloma.

A 46-year-old woman with incidentally discovered thyrotropin (TSH)-producing pituitary adenoma showed endocrine data which was consistent with TSH-producing pituitary tumor. However, she showed only slight hyperthyroidism and the oversecretion and autonomous secretion of TSH from the tumor seemed to be limited from the results of several endocrine examinations. Immunohistochemical examination revealed that not only TSH-beta and TSH-alpha but also prolactin and growth hormone synthesizing cells were present in the tumor tissue. Pituitary-transcription activator 1 (Pit-1) immunoreactivity was also detected in the adenoma cell nuclei. It was conceivable that the presented TSH-producing adenoma clinically located close to the non-functioning adenoma and Pit-1 may have played an important role in the multidirectional differentiation or development of this tumor.

Adenoma↗
PubMed1995

Autoradiographic measurement of regional brainstem blood flow. Findings after 2 hours of occlusion of the unilateral anterior inferior cerebellar artery and 30 minutes' occlusion of the unilateral vertebral artery.

Using [14C]iodoantipyrine, regional brainstem blood flow was measured in the rat 2 h after occlusion of the left anterior inferior cerebellar artery (AICA) and 30 min after occlusion of the left vertebral artery (VA). Two hours after occluding the left AICA, the mean +/- SEM value of blood flow in 6 animals in the right superior olive was 2.13 +/- 0.13 ml/g/min and in the left side, 1.13 +/- 0.11. Thirty minutes after occlusion of the left VA, there were no significant differences between the right and left sides. Blood flow changes were assessed in the hindbrain structures between the control group, 30 min after occlusion of the left VA and 2 h after occlusion of the left AICA. Changes observed in the blood flow in the hindbrain structures suggest that the extra volume of the blood flow might be concealed in the brainstem. However, whether the recovery of the blood flow rate indicates the recovery of the brainstem function remains unclear.

Animals↗
PubMed1995

ABR findings in brainstem ischemia: occlusion of the left anterior inferior cerebellar artery.

ABR was measured ipsilaterally following permanent left anterior inferior cerebellar artery (AICA) occlusion to assess the discrepancy in recovery between blood flow and function in the rat brainstem. Three types of wave patterns were classified: in type 1, all components disappeared: in type 2, all components disappeared transiently, then re-appeared; and in type 3, only a significant increase in the latency difference between components I-IV was noted. In type 2, we suggest that all components re-appeared because cochlear blood flow was re-established quickly by collateral circulation.

Animals↗
PubMed1995

Thymosin fraction 5 does not influence urinary tract carcinogenesis by phenacetin and N-butyl-N-(4-hydroxybutyl)nitrosamine in NON/Shi mice.

The effect of thymosin fraction 5 (TF5) on the promotion and progression phases of urinary tract carcinogenesis induced by consecutive administration of phenacetin and N-butyl-N-(4-hydroxybutyl)-nitrosamine (BBN) in NON/Shi mice was investigated. The study was carried out twice with a minor modification to the protocol in the second experiment. Fifty-seven male NON/Shi mice in experiment 1 and 100 mice in experiment 2 were each divided into four groups. Phenacetin was administered for 8 weeks in experiment 1 and 12 weeks in experiment 2, and subsequently BBN was given for 6 weeks in both cases, for total observation periods of 30 and 34 weeks, respectively. Sixty micrograms of TF5 per mouse was inoculated subcutaneously twice a week during (group 2) or after (group 3) BBN exposure, or both periods (group 4). Group 1 served as a control group without TF5 treatment. Histopathological examination revealed no effects on either induction of urinary tract carcinomas or distant metastasis from renal pelvic carcinomas in either experiment.

Animals↗
PubMed1995

[The human chorionic gonadotrophin reference standard (Control 941) of the National Institute of Health Sciences].

Raw human chorionic gonadotrophin material was examined for preparation of the "Human Chorionic Gonadotrophin Reference Standard (Control 941)". The candidate material was assayed against the 3rd International Standard by the rat ovarian weight method. The potency of the new standard was defined as 1180 international units per ampoule as the result of 18 assays in four collaborative laboratories.

Chorionic Gonadotropin↗