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Biomedical subjects

T Eguchi

Publications and source records attributed to T Eguchi.

At least 109 records · Page 6Linked to original sources
PubMed1995

Age-dependent changes in response of rat prostatic tissues to isoproterenol and forskolin: changes with sexual maturation in function of G proteins.

Developmental changes in the responses of rat ventral prostate to isoproterenol (IPR) and forskolin (F) were studied in relation to the function of beta-adrenoceptor-adenylate cyclase system. The response of adenylate cyclase in the tissues to IPR at 10(-7)M and above was steadily enhanced after birth and reached a maximum at 12 weeks, followed by a decrease with age. In contrast, the response of the enzyme to F at 10(-7)M and above was highest at 2 weeks, but thereafter decreased. The changes in the response of the enzyme to IPR coincided with changes in the beta-adrenoceptor density and the binding ability of GTP binding proteins (G proteins) to GTP. The ADP-ribosylation of inhibitory G proteins (Gi proteins) catalyzed by pertussis toxin (IAP) decreased 70% in the tissues from 4 to 8 weeks, and then maintained this level. On the other hand, the ADP-ribosylation of stimulatory G proteins (Gs proteins) catalyzed by cholera toxin (CT) increased only 20% in the tissues from 2 to 4 weeks. Thus, the ratio of ADP-ribosylation of Gs to that of Gi significantly increased from 4 weeks, reaching a maximum at 12 weeks, but thereafter decreased gradually with age. These changes paralleled those in the function of G proteins and the response of the enzyme to IPR. It is suggested that the rapid and marked decrease in apparent level of Gi proteins in the rat ventral prostate after 4 weeks may have a key role in controlling the function of the beta-adrenoceptor-adenylate cyclase system in the tissues.

Adenosine Diphosphate Ribose↗
PubMed1995

Mechanism of isoproterenol-induced heterologous desensitization of mucin secretion from rat submandibular glands. Regulation of phosphorylation of Gi proteins controls the cell response to the subsequent stimulation.

Short-term treatment of rat submandibular tissues with 10 microM isoproterenol (IPR) resulted in reduction of mucin secretion in response to the agonist during further incubation, and in increases in EC50 values. This IPR-induced reduction of secretion was coupled with selective decreases in the number of beta-adrenoceptors in the tissues and in their affinity for agonists, as assessed by measurement of the specific binding of [3H]dihydroalprenolol. Treatment of the tissues with IPR caused a 30% decrease in IPR-stimulated adenylate cyclase activity and a 25% increase in the GTP binding capacity of inhibitory G proteins (Gi proteins). This IPR treatment triggered a 60% increase in the ability of pertussis toxin (IAP) to catalyze ADP-ribosylation of Gi proteins in the tissue membranes. Enhanced function of stimulatory G proteins (Gs proteins) was observed only during the first incubation of the tissues with IPR. The IAP-catalyzed ADP-ribosylation of Gi proteins in tissues treated with IPR was decreased by prior treatment with cyclic AMP dependent protein kinase, but was increased markedly by prior treatment with alkaline phosphatase. Neither IPR-induced desensitization of protein secretion nor increase in the IAP-catalyzed ADP-ribosylation of Gi proteins was observed in the tissues pretreated with 0.25 microM okadaic acid. These findings suggest that the regulation of Gi protein phosphorylation plays an important role in the IPR-induced heterologous desensitization of mucin secretion from rat submandibular glands.

Adrenergic beta-Agonists↗
PubMed1995

Inhibition of vitamin D3-induced cell differentiation by interferon-gamma in HL-60 cells determined by a nitroblue tetrazolium reduction test.

The combined effects of 1 alpha,25-dihydroxyvitamin D3 [1,25(OH)2D3] and interferon-gamma (IFN-gamma) or tumor necrosis factor alpha (TNF-alpha) on cell differentiation in HL-60 human promyelocytic leukemia cells were examined by a nitroblue tetrazolium (NBT) reduction test. 1,25(OH)2D3 at the concentrations of 7-70 nM induced NBT-positive cells, which was used as a criterion of cell differentiation. IFN-gamma itself showed little effect on induction of NBT-positive cells or on cell growth at a concentration up to 1000 U/ml. However, in a combination of 1,25(OH)2D3 with IFN-gamma (100 and 300 U/ml), cell differentiation was strongly inhibited and was accompanied by growth inhibition. Treatment with a combination of 1,25(OH)2D3 and TNF-alpha or IFN-gamma and TNF-alpha showed an additive effect on cell differentiation. IFN-gamma seems to act as a specific inhibitor for 1,25(OH)2D3-induced cell differentiation. To elucidate the cause of the inhibition of cell differentiation by IFN-gamma, the ability of the cells to produce superoxide (O2-) was examined after culture for 5 days in the presence of 1,25(OH)2D3 and IFN-gamma. The results indicated that the inhibition of IFN-gamma was caused by a reduction in the ability of the cells to produce O2- in response to stimulation by 12-O-tetradecanoylphorbol-13-acetate (TPA).

Calcitriol↗
PubMed1995

Impaired colour discrimination among workers exposed to styrene: relevance of a urinary metabolite.

OBJECTIVES: To survey the loss of colour vision among Japanese workers who have been exposed to styrene concentrations currently considered low (about 20 ppm). Also to assess the effects of styrene by examination of the nature of the relation between disorder of colour vision and age, alcohol consumption, and other variables. METHODS: Colour discrimination was examined in 64 male workers exposed to styrene (mean age; 38.0, mean exposed years; 7.0) and in 69 controls (mean age; 38.0). A standardised questionnaire was adopted to collect work history, occupational or non-occupational solvent exposure, alcohol consumption, and drug use. Colour vision was evaluated by the Lanthony desaturated panel D-15 test. The results of the test were expressed as the colour confusion index (CCI). RESULTS: The mean atmospheric styrene concentration was about 20 ppm. The mean urinary concentration of mandelic acid was 0.22 g/l. There was a significant difference in CCI between exposed workers and age matched controls. Colour vision of workers whose concentration of urinary mandelic acid was > or = 0.42 g/l was significantly impaired when compared with workers whose concentration was < 0.42 g/l. Multiple linear regression analysis that controlled confounding variables such as age, alcohol consumption, smoking, and educational attainment showed that the CCI was significantly related to the concentration of urinary mandelic acid. In both exposed workers and controls, the types of defects were mostly blue-yellow loss, although a few subjects showed complex loss. No one showed only red-green loss. CONCLUSIONS: These findings suggest that exposure to moderate styrene concentrations can lead to impairment of colour vision, and that there is a significant correlation with the urinary metabolite of styrene.

Adult↗
PubMed1995

Amino acid sequence of alpha- and beta-polypeptide chains of turkey (Meleagris gallopavo) hemoglobin.

Two hemoglobin components are recognized in erythrocytes of the adult turkey (Meleagris gallopavo). We determined the amino acid sequences of turkey alpha A-, alpha D- and beta-globin from intact globin chains and chemical cleavage fragments. The sequences are highly similar to the hemoglobin of the Phasianidae, chicken, Japanese quail and pheasant. Turkey and pheasant beta-globin are identical. The amino acid sequence of turkey alpha A-globin differs by only one residue from chicken alpha A-globin. Phylogeny trees from alpha A-, alpha D- and beta-globin were constructed by the neighbor-joining method. Although the trees generated from alpha A- and beta-globin were similar, that from turkey alpha D-globin differed.

Amino Acid Sequence↗
PubMed1995

[Experimental study on hypertensive crises in epileptic seizures--changes in pial artery diameter, intracranial pressure and regional cerebral blood flow].

It is well known that severe hypertension occurs during epileptic seizures, but little information is available concerning these hypertensive crises. We therefore investigated them by monitoring regional cerebral blood flow (rCBF), intracranial pressure (ICP) and pial artery diameter (PAD) in paralyzed mechanically-ventilated cats with penicillin-induced seizures. The animals were assigned to two groups. In one (Group H), they were maintained in an untreated state. In the other (Group C), spinal cord injury was performed in advance to prevent the rise in arterial blood pressure during the seizures. In both groups, the values of the various parameters increased during seizure activity, but the increases in group H, were greater than in group C. In both groups, PAD, rCBF and ICP increased immediately at the onset of the seizures with no hypertension. In group H, further increases in PAD, rCBF, and ICP were found concurrent with the elevation of arterial blood pressure in the latter half of the seizure, while in group C, rCBF decreased concurrent with the increase in ICP in the latter half of the seizure, although PAD was found to be maximal. These findings suggest that hypertensive crises during epileptic seizures represent a protective mechanism to maintain perfusion pressure.

Animals↗
PubMed1994

Exposure monitoring and health effect studies of workers occupationally exposed to cyclohexane vapor.

A survey was conducted in the second half of a working week on 33 women who either applied glue (with cyclohexane as an almost exclusive solvent component) or worked in the vicinity of glue application. Carbon cloth-equipped diffusive samplers were used for personal measurement of time-weighted average intensity of exposure to the solvent. The geometric mean and the highest cyclohexane concentration observed in air were 27 ppm and 274 ppm, respectively. Concentrations of cyclohexanol in urine samples and cyclohexane in whole blood and serum collected at the end of a shift showed significant correlations with the solvent exposure levels. Urinary cyclohexanone also correlated, but with a smaller correlation coefficient. The observation suggests that cyclohexanol in urine and cyclohexane in blood or serum collected at the end of a shift are useful indicators of occupational exposure to cyclohexane vapor. Quantitative estimation of balance at the end of the shift suggested that only a minute portion (< 1%) of cyclohexane absorbed is excreted in the urine as cyclohexanol, almost exclusively as a glucuronide. A survey of subjective symptoms revealed an increase in the prevalence of "dimmed vision " and "unusual smell", but hematology and serum biochemistry testing did not indicate any specific signs.

Adult↗
PubMed1994

Effect of betaine on S-adenosylmethionine levels in the cerebrospinal fluid in a patient with methylenetetrahydrofolate reductase deficiency and peripheral neuropathy.

A 16-year-old Japanese girl with 5,10-methylenetetrahydrofolate reductase deficiency showed peripheral neuropathy. There were no significant responses to vitamin B6, vitamin B12 or folate, given alone or in combination. With the addition of betaine monohydrate, she has been free from gait disturbance and muscle weakness. The concentration of S-adenosylmethionine in cerebrospinal fluid, which was undetectable before receiving betaine monohydrate, increased to about the normal level 24 months after treatment with betaine monohydrate.

Adolescent↗
PubMed1994

Malignant brain stem hyperthermia caused by brain stem hemorrhage.

BACKGROUND: We report two cases of brain stem hemorrhage characterized by severe hyperthermia, rhabdomyolysis, acute renal failure, and a rapidly fatal course. METHODS: A 55-year-old man and a 65-year-old man were admitted with coma-producing brain stem hemorrhage accompanied by hyperthermia. Both underwent ventricular drainage. RESULTS: Within 1 day of onset, both patients developed hyperthermia of over 41 degrees C, increased serum creatine phosphokinase (CPK) level indicating rhabdomyolysis, and acute renal failure. One patient died on the second day and the other on the third day after onset despite supportive treatment. CONCLUSIONS: These cases of brain stem hemorrhage with fulminant hyperthermia should be distinguished from those with simple hyperthermia. They may represent a kind of malignant hyperthermia, in which case dantrolene sodium might be beneficial. Monitoring serum CPK levels would be of help in making the diagnosis early in the course.

Aged↗
PubMed1994

Intracranial vertebral artery dissections: clinical, radiological features, and surgical considerations.

We reviewed 24 patients with intracranial vertebral artery dissections treated during the last 12 years. Sixteen patients were admitted with subarachnoid hemorrhage (SAH) and 8 did not have SAH. The mean age at the time of onset was 50.0 years. Male preponderance was noted. Among 21 patients with acute onset, 6 (29%) experienced prodromal neck pain and 3 (60%) of 5 SAH patients showed nuchal stiffness when examined within 6 hours of onset. The preoperative angiographical findings were uniform in SAH cases in contrast to the varied angiographical findings seen in non-SAH cases. So-called pearl and string sign was observed in most SAH cases, but the "string" was often so short and wide that the term "constriction" appeared more suitable. From intraoperative observations, the angiographical point of constriction seemed to represent the proximal or distal end of dissection. As for treatment, 19 patients underwent 20 surgeries. Trapping was performed in eight surgeries, base clipping was performed in five, and proximal clipping was performed in seven. Both trapping and base clipping prevented further bleeding, but trapping was associated with a high rate of postoperative lower cranial nerve palsy. Postoperative neurological complications were less frequent after proximal clipping, but subsequent postoperative bleeding occurred in one patient treated by this technique. The overall long-term outcome in the surgically treated cases in our series was favorable, but most patients suffered from various degrees of uncomfortable dysphagia or hoarseness for some period after surgery. It was also noted that, in half of the disabled cases, the major disability was attributable to lower cranial nerve palsy and respiratory troubles that developed postoperatively.

Adult↗
PubMed1994

[Health status, social networks and support systems of elderly men and women in a large city and in former coal-mining areas--a population-based comparative study of 70-year-old residents of Sapporo and Yubari].

In order to analyze the different features of the social network, social support system and health status of elderly people, a survey was performed of the social environment and health related issues among 70 year-old men and women in Sapporo, a large city, and Yubari, a small city which has experienced coal mine closures, both in Hokkaido prefecture. The results were as follows: 1. In Yubari, the health status of the elderly living alone was better than those with other familial categories such as living with their spouse, or with the families of their children. In contrast, the status of the elderly living alone in Sapporo was worse than the others. The mean numbers of out-patient visits and hospital admissions during the previous one year were higher among elderly people living alone in both areas. 2. There were large differences in social support and social network in the two areas and among the living status of the elderly. In particular, persons living alone in Sapporo had statistically significantly lower amount of support than others. Elderly people in Sapporo had fewer contacts with their neighbors and only a small number of them participated in community-based social associations compared with the same age groups in the city of Yubari. 3. An extremely small number of the elderly were provided formal support from official personnel such as public health nurses, district welfare commissioners and so on. The results of this study suggest the need for more formal and informal networks to provide for social support for those elderly men and women living alone in large cities.

Aged↗
PubMed1993

Erythrocyte galactokinase assay with high performance liquid chromatography.

An assay for erythtocyte galactokinase based on high performance liquid chromatographic determination of galactose 1-phosphate (Gal-1-P) is described. The determination of Gal-1-P was applied to a post-column fluorometric detection of reducing sugars using arginine. This method is as sensitive and accurate as conventional radioisotopic methods, but needs no radioisotopic facilities. It requires only a small blood sample and is suitable as a follow-up test in neonatal screening.

Adult↗
PubMed1993

Spontaneous large intra-abdominal wall haematoma as a rare complication in a maintenance haemodialysis patient.

The incidence of spontaneous bleeding in various parts of the body has been reported to be high in patients receiving maintenance haemodialysis. We present a case of spontaneous large haematoma of the intra-abdominal wall which developed in a 71-year-old Japanese man with 9 years' maintenance haemodialysis. Due to the clinical symptoms and signs, ileus was suspected and an emergency operation was performed. In maintenance haemodialysis the possibility of spontaneous bleeding should always be considered whenever unexplained and unexpected symptoms and signs are apparent.

Abdominal Muscles↗