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Biomedical subjects

M Nishida

Publications and source records attributed to M Nishida.

At least 361 records · Page 20Linked to original sources
PubMed1992

Endothelins. Myocardial actions of a new class of cytokines.

There is growing evidence to support the existence of a dynamic interaction in vivo between cardiac myocytes and adjacent microvascular endothelial cells in the regulation of both cardiac myocyte and possibly endothelial cell phenotype and function. Endothelins may be only one of several endogenous cytokines or autocoids that are released by the cardiac microvascular and/or endocardial endothelium and transported vectorially to adjacent myocytes that could modify cardiac contractile state, perhaps in response to changes in microvascular blood flow. Similarly, cardiac myocytes themselves could release cytokines that could directly affect endothelial cell proliferation or angiogenesis and indirectly elicit or modify the release of endothelium-derived cytokines and autocoids. Thus, in addition to modifying function, endothelial cell-cardiac myocyte interactions may also be of importance in the dynamic events that lead to myocardial wall remodeling and angiogenesis during hypertrophic growth and in the response to cardiac injury.

Amino Acid Sequence↗
PubMed1992

Characterization of thyroidal membrane-bound Mg-adenosinetriphosphatase activated by trypsin or poly-L-lysine.

The Mg-adenosinetriphosphatase (ATPase) in the thyroidal NaI-treated microsome fraction was activated by treatment with basic polyamino acids or trypsin, but not with acidic polyamino acids and basic proteins such as lysozyme and ribonuclease. The enzyme kinetics showed that the activation of trypsin or poly-L-lysine was due to an increase in the maximal velocity of the hydrolyzing reaction without a change in the affinity of the enzyme for its substrate. A break at about 25 degrees C was observed in the Arrhenius plots of Mg-ATPase in the trypsin- or poly-L-lysine treated preparations, but there was no break in the control preparation. These results suggest that the activating effect of trypsin or poly-L-lysine on Mg-ATPase activity in the thyroidal NaI-treated microsome fraction is related to the lipid environment surrounding the enzyme molecule in the thyroid cell membrane.

Animals↗
PubMed1992

Beneficial effect of stopping smoking on future cardiac events in male smokers with previous myocardial infarction.

UNLABELLED: We assessed the effect of stopping smoking on future cardiac events (cardiac death and non-fatal myocardial infarction (MI)) in 90 male smokers with previous MI by a prospective follow-up study. At the time of enrollment, the patients were divided into 2 groups according to their current smoking status (Group A: those who had stopped smoking (n = 60), and Group B: those who were still smoking (n = 30)). Follow-up was performed prospectively by annual postal questionnaires. During the mean follow-up period of 3.1 +/- 1.4 years, 13 cardiac events (11 cardiac deaths and 2 cases of non-fatal MI) occurred in the 87 evaluable patients. The cardiac event rates in Groups A and B were 8.5% and 28.6%, respectively, and the relative risk was 3.4 (Group A vs B, p less than 0.05) by univariate analysis. The relative risk using multivariate analysis (Cox) was also statistically significant (3.1, p less than 0.05). HDL-cholesterol was significantly lower in Group B than in Group A, but other coronary risk factors apart from smoking were not significantly different between the two groups. At the end of the follow-up period, 89.8% of the patients in Group A remained nonsmokers and 21% of the patients in Group B had stopped smoking. CONCLUSION: Stopping smoking significantly reduced the risk of future cardiac events in male smokers with previous MI. This prospective follow-up study demonstrated that a significant reduction in the risk of future cardiac events could be achieved by stopping smoking in this group of patients.

Adult↗
PubMed1992

A simple ergometer for 31P NMR spectroscopy during dynamic forearm exercise in a whole body magnetic resonance imaging system.

The purpose of this study was to construct a simple ergometer for the 31P NMR spectroscopic study of dynamic forearm exercise in a whole body magnetic resonance imaging system and to evaluate the total system and the physiological response to this type of exercise using a multistage protocol. The system consisted of a completely nonmagnetic assembly including a rope, pulley and weights. The work of lifting weights was quantitated. The exercise protocol of 1-min increments in work load enabled subjects to reach maximal effort. Phosphocreatine decreased linearly with an increase in work load and was accompanied by a fall in pH and an increase in lactate level in the antecubital vein of the exercising forearm; concomitantly, there was a slight increase in whole body oxygen uptake and heart rate. Spectroscopy gave reproducible results using this exercise protocol. These results demonstrate that this system provides a reliable means for performing 31P magnetic resonance spectroscopy studies during forearm exercise.

Adenosine Triphosphate↗
PubMed1992

Bilateral symmetrical cerebral arteriovenous malformations in the basal ganglia--case report.

A 21-year-old male presented with visual disturbance followed by severe headache. Computed tomography showed right thalamic hemorrhage entering the right lateral ventricle. Cerebral angiography revealed bilateral symmetrical arteriovenous malformations (AVMs) fed by the lenticulostriate, anterior choroidal, and lateral posterior choroidal arteries and draining into the vein of Galen. Partial removal of the right AVM induced bleeding on the left side, probably due to postoperative hemodynamic changes. Bilateral symmetrical cerebral AVMs are extremely rare, but provide serious problems for surgical intervention in the deep cerebrum.

Adult↗
PubMed1992

A binding profile of manganese to the nucleus of rat liver cells, and manganese-induced aberrations in thyroid hormone content and RNA synthesis in the nucleus.

Manganese (Mn) is accumulated in the nuclear and mitochondrial fractions when excess Mn is administered. However, little is known with respect to the behaviors of Mn in nuclei. In the present study, rats were given excess Mn and the nuclei were purified from liver cells by differential and sucrose gradient centrifugations. Being subjected to equilibrium dialysis with a radioactive 54Mn, the binding capacity of Mn in nuclei from the control rat was five-fold higher than BSA, which was used as a reference protein; and the capacity of 54Mn-binding rose in the nuclei from the Mn-treated animals in comparison with those from the control. On the analyses of nuclear materials with partial solubilization, sepharose column chromatography and HPLC, there were two major fractions which associated with a lot of Mn; one fraction was of large molecules of DNA, and the other fraction seemed to be peptides with small molecular weights. Therefore, Mn may open up a superhelical structure of DNA to provide more negatively charged phosphate moiety as a binding-site for a positively charged Mn. The results also disclosed a possible aberration in biological functions due to excess Mn in nuclei; the apparent association constant of triiodothyronine, a physiologically active thyroid hormone, to the nucleus was reduced by 75% and the uptake of 14C-labelled orotic acid to a newly synthesized RNA in the liver was severely inhibited.

Animals↗
PubMed1992

[A study on creatine uptake into human erythrocytes: relation to erythrocyte aging].

In order to assess the relation between creatine uptake into human erythrocytes and erythrocyte aging, actual influx of creatine into erythrocytes and creatine contents in erythrocytes were measured by using method of high performance liquid chromatography and isotopic estimation of 14C-creatine concentration. Actual influx of creatine into erythrocytes was showed rapidly, in spite of constant contents of erythrocyte creatine under the condition to be incubated at 37 degrees C for approximate 4 hours in isotonic saline containing high concentration of creatine. Km values of the creatine uptake into young erythrocytes were evidently smaller than that into old erythrocytes. On the other hand, no significant difference of Vmax values was observed to be dependent on erythrocyte aging.

Creatine↗
PubMed1992

[Efficacy of individual smoking cessation instructions for general smokers among clients of a health center].

Smoking cessation instruction for individuals using a standardized smoking cessation manual and a handout developed by the authors was studied in a controlled trial among employees who visited a health center for Industrial Safety and Health Law mandated annual health examinations. Smokers in the study group were given 5-10 minutes smoking cessation instruction mainly by public health nurses and nutritionists following the above-mentioned manual and using the handouts. Subjects in both groups were interviewed by telephone to assess changes in smoking habits one month after the first contact. Smoking clients who came on Friday (132) and on Monday (93) were assigned to study and control groups, respectively. One hundred and nineteen members (90.2%) of the study group and 88 (94.6%) of the control group were successfully followed until one month after the initial contact. Seven subjects in the study group were not smoking one month after the instruction, while no one gave up smoking in the control group (p less than 0.05). It was confirmed by telephone survey that 6 of the 7 subjects who were not smoking at one month were still maintaining abstinence from smoking one year after the instruction. Smokers who did not stop smoking reported a reduction in their smoking dose in the study group. Lighter smokers reacted more readily to instruction than did heavier smokers and the knowledge level of subjects was positively associated with the success rate.

Adolescent↗
PubMed1992

[Effect of vasopressin on phospholipid metabolism in cultured rat mesangial cells].

Aqueous solutions containing extracts of cultured rat mesangial cells treated with and without arginine vasopressin (AVP) were measured by phosphorus-31 nuclear magnetic resonance spectroscopy (31P-NMR). Ratios of the NMR signal intensities of phospholipids in the solutions were calculated with the areas of those resonance lines. Furthermore, prostaglandin E2 (PGE2) production and incorporation of 3H-methyl group into phospholipids in mesangial cells were observed in the presence and in the absence of AVP. We examined the role of AVP in the phospholipid metabolism of mesangial cells by the results from these three kinds of experiments. Ratios of (phosphorylcholine + glycerophosphorylcholine)/(phosphorylethanolamine + glycerophosphorylethanolamine), (PC + GPC)/(PE + GPE), and PC/PE increased significantly 5 min after AVP administration. Ratios of (GPE + GPC)/(PE + PC) and GPE/PE also increased significantly 30 min and 60 min after administration of AVP. The production of PGE2 increased with AVP treatment. This increment was inhibited with mepacrine and Adenosyl-S-isobutyl mercaptan (SIBA). Incorporation of 3H-methyl group into cellular phospholipids was accelerated with AVP, and then the resolution of methylated phospholipids and the release of PGE2 increased. These findings indicate that phospholipid methylation may be accelerated with AVP treatment and phosphatidylcholine, synthesized by transmethylation pathway, may be important as the substrate for PGE2 production in mesangial cells.

Animals↗
PubMed1991

Determination of atropine in biological specimens by high-performance liquid chromatography.

A sensitive and selective method for the determination of atropine in biological specimens has been developed. Samples alkalinized with sodium hydroxide were extracted with dichloromethane, and the organic phase was evaporated in a water-bath at 50 degrees C for ca. 10 min. The residue was dissolved in the mobile phase and injected into a reversed-phase column (TSK gel ODS-120A). The retention time for atropine could be varied by changing either the acetonitrile-water ratio in the mobile phase or the pH of the mobile phase. Acetonitrile-water (2:8, v/v) containing 6 mM phosphoric acid was used as mobile phase. Samples of 200 microliters or less were injected into the chromatography and measured at 215 nm. The recoveries of atropine added to drug-free specimens were satisfactory with coefficients of variation of 4% or less. Ninety-two compounds tested did not interfere with the assay of atropine. The method has been applied for monitoring atropine concentrations in cases of organophosphate and drug poisoning.

Adult↗
PubMed1991

Dynamic sweating response of man to infrared irradiation in various spectral regions.

In an attempt to detect differences in the thermal effect of infrared irradiation of different wave-lengths, transient sweating response to infrared irradiation in various spectral regions was examined. In Series 1, the ventral or dorsal surface of the nude subject was irradiated repetitively for a period of 4 min (2 min on, 2 min off) by each of three kinds of infrared heaters with main emissivity in 'near-infrared' (NIR; 0.7-2.8 microns), 'intermediate-infrared' (MIR; 1.5-5.8 microns), and 'far-infrared' (FIR; 2.8-25 microns) regions. The sweating response on a non-irradiated area tended to be the greatest with MIR, while the magnitude of the sweating response on the irradiated area showed no consistent differences among various wavelengths. The results infer that MIR stimulated cutaneous thomoreceptors most effectively, while its direct effect on local sweat gland activity was minimal. In Series 2, the effects of 9-12 min irradiations in more restricted ranges of wavelength were compared by the combination of the three kinds of heaters with filters (translucent to wavelength ranges of 1.3-2.7, 2.7-3.5, 3.6-8.0 microns, respectively). The sweating response on a remote area was predominantly greater with the range of 2.7-3.5 microns than with the other wavelength ranges, while the local effect on sweating was minimal with this range. The results of Series 2 reinforce those of Series 1, indicating that the degree of stimulation of cutaneous thermoreceptors and of direct thermal effect on sweat gland activity differ with spectral regions incident on the skin, thus affecting local and remote effects on the sweating response.

Adolescent↗
PubMed1991

Relationship between the onset of dysmenorrhea and histologic findings in adenomyosis.

An attempt was made to evaluate the relationship between histologic findings of adenomyosis and onset of dysmenorrhea. Thirty-four cases of histologically diagnosed adenomyosis were investigated in this study. One large sample cut along the longitudinal axis was made and examined to evaluate the histologic parameters and CA 125 levels. Dysmenorrhea was classified into grade I (absent or mild) and grade II (severe). Localization of adenomyosis was divided into type I, adenomyosis continuous from the surface endometrium (29 cases), and type II, adenomyosis present on the serous side of the uterus and not continuous from the surface endometrium (five cases). We made type I adenomyosis, which included 13 cases of grade I and 16 cases of grade II, the focus of our investigation. The parameters that correlated with dysmenorrhea were the number of islands of adenomyosis and glands, distance of invasion, relative rate of invasion, and CA 125 levels. The differences between grades I and II were apparent in the frequency distribution tables, with dysmenorrhea occurring at invasion rates of 80% and greater.

Adult↗
PubMed1991

Introduction of monoclonal antibodies to bromodeoxyuridine to monitor hepatic regeneration.

The effect on the liver of portal vein and/or bile duct branch ligation was examined in rabbits by measuring cellular kinetics using the bromodeoxyuridine labeling index. Twenty-four days after ligation of a portal vein and/or bile duct branch, similar degrees of compensatory regeneration were observed. However, there were significant differences in the pattern in which regeneration developed. Compensatory regeneration after ligation of a bile duct follows a different pattern than that after portal vein branch ligation.

Animals↗
PubMed1991

Juvenile granulosa cell tumor in association with a high serum inhibin level.

Inhibin is a glycoprotein hormone produced mainly by ovarian granulosa cells. Recently measurement of serum inhibin levels was made possible by radioimmunoassay. We describe a patient with a juvenile granulosa cell tumor, a distinctive and rare form of granulosa cell tumor. This patient's serum inhibin level was extremely high preoperatively and returned to normal after the tumor was resected. This case suggests that serum inhibin level may be a useful marker of granulosa cell tumors.

Biomarkers, Tumor↗
PubMed1991

Anticancer activity of the combination of cisplatin and etoposide in endometrial cancer-bearing nude mice.

We investigated the efficacy of the combination of cisplatin and etoposide in endometrial cancer using mice bearing human endometrial cancer. Cisplatin (5 mg/kg) plus etoposide (10 mg/kg) caused markedly greater inhibition of the growth of medium-sized tumors (96.1% inhibition) than cisplatin alone at the same dose. Similarly, the combination of cisplatin (7.5 mg/kg) and etoposide (10 mg/kg) produced a significantly higher complete remission rate in small tumors, compared with cisplatin alone at the same dose (82.6% vs 35.3%, P less than 0.01). As a single agent, etoposide had almost no inhibitory effect on tumor growth and produced a considerably lower complete remission rate. Total platinum and etoposide concentrations in serum and tumor tissue were unaltered when these agents were used either singly or in combination. Our results suggested that combination cisplatin-etoposide therapy was synergistic against endometrial cancer.

Animals↗