DEGUCHI, Y. and OGATA, A. Relationship between Serum SeleniumConcentration and Atherogenic Index in Japanese Adults. Tohoku J. Exp. Med., 1991, 165 (4), 247-251-In mass health screening of the inhabitants of a coastal district in Fukui Prefecture, venous blood samples were collected from 304 men (aged 22-87 years) and 223 women (aged 23-84 years). We examined whether serum selenium concentration was related to atherogenic index [=(total serum cholesterol-high-density-lipoprotein cholesterol)/high-density-lipoprotein cholesterol] by multiple regression analysis with age, body mass index, and smoking and drinking habits as independent variables. Atherogenic index was a significant increasing factor of serum selenium concentration in the entire male subjects and the female subjects aged above 60 years.
KATSUYA, T., HIGAKI, J., MIKI, T., NAKURA, J., IKEGAMI, H., MORISHITA, R., NAGANO, M., HIGASHIMORI, K., NAKAMURA, F., MIKAMI, H. and OGIHARA, T. Substrain Comparison of Genetically Hypertensive Rats Using DNA Fingerprinting, and Genetic Analysis of Blood Pressure in the Inbred Rats. Tohoku J. Exp. Med., 1991, 165 (4), 253-260-Using DNA fingerprinting, genetic heterogeneity or homogeneity was studied between substrains of spontaneously hypertensive rats (SHR) and Wistar-Kyoto (WKY) rats maintained in Japan. Using human myoglobin minisatellite 33.15 as a probe, we did not detect any inter- or intra-substrain genetic heterogeneities in HinfI digests of SHR or WKY rat DNA. However, analysis of Sau3AI digests of rat DNA using mouse C-6 gene as a probe revealed intra-substrain heterogeneity of 1-2 DNA bands in one of the WKY rat substrains. In the other substrains of SHR and WKY rats, there existed no intra-substrain heterogeneities, but several inter-substrain heterogeneities were observed in both SHR and WKY rats. In another experiment using the inbred substrains of SHR and WKY rats which have been confirmed as genetically homogeneous, we produced F1 and F2 rats, and biometrically analyzed their systolic blood pressure. The results suggested that there may be 1-4 dominant antihypertensinogenic genes with high heritability of 0.6-0.7.
SUZUKI, H. Effects of a Benzodiazepine Antagonist, Ro 15-1788, onHippocampal Field Potentials in Freely Moving Rats. Tohoku J. Exp. Med., 1991, 165 (4), 261-270-Effects of a benzodiazepine receptor agonist (diazepam) and an antagonist (Ro 15-1788, flumazenil) administered separately or in combination on field potentials recorded from the hippocampal dentate area were examined in unanesthetized, unrestrained rats. Population excitatory postsynaptic potentials (EPSPs) evoked by stimulation of the perforant path were depressed significantly by diazepam (4mg/kg, i.p.). However, diazepam did not affect the firing (spike) threshold of dentate granule cells. The injection of Ro 15-1788 (4 mg/kg, i.p.) alone affected neither excitatory synaptic transmission nor population spike threshold. Strength of γ-amino butyric acid-mediated recurrent inhibition as measured by the paired-pulse technique was potentiated by diazepam but unaffected by Ro 15-1788. However, the diazepam-enhanced inhibition was reversed by a subsequent administration of Ro 15-1788. Previous studies indicate that Ro 15-1788 acts not only as a selective benzodiazepine antagonist but also as a partial agonist-antagoinst or an inverse agonist depending probably on doses. The present study demonstrated that Ro 15-1788 acted as a pure antagonist at low doses. These data suggest that the clinical use of Ro 15-1788 at high doses against comas induced by unidentified drugs could worsen the conditions and that low doses are recomendable for initial treatments because of its pure antagonist action.
SHIRATO, K., ISHIKAWA, K., KANAZAWA, M., NAKAJIMA, T., MUNAKATA, K., SAKUMA, M., HANEDA, T. and TAKISHIMA, T. Effect of Pericardium of RegionalMyocardial Systolic Function in Acute Ischemia. Tohoku J. Exp. Med., 1991, 165 (4), 271-282-To know whether or not the pericardium affects regional myocardial systolic function in acute ischemia, we measured ischemic and non-ischemic segment lengths of the left ventricle using ultrasonic crystals in 10 open-chest dogs with the pericardium preserved. When the left ventricular pressure and segment lengths were stable after left circumflex coronary occlusion, we opened the pericardium widely. After coronary occlusion, end-diastolic length (EDL) in ischemic and non-ischemic segments increased, and the ischemic segment showed paradoxical systolic expansion while the non-ischemic segment increased its active shortening. After pericardiectomy, heart rate, left ventricular systolic pressure, and peak positive and negative dP/dt did not change. EDL in ischemic and non-ischemic segments further increased from 12.02±0.18 to 12.50±0.16mm (mean±S.E., p< 0.01) and from 11.12±0.20 to 11.45±0.18mm (p<0.05), respectively, despite the concomitant fall in left ventricular end-diastolic pressure (LVEDP) from 12.4±0.6 to 10.6±0.8mmHg (p<0.01). End-systolic length in ischemic and non-ischemic segments also increased from 12.37±0.25 to 12.70±0.20mm (p<0.05) and from 8.50±0.13 to 8.74±0.13mm (p<0.01), respectively, although the left ventricular end-systolic pressure did not change. Maximum expanded systolic length of the ischemic segment also increased from 12.99±0.20 to 13.42±0.16mm (p<0.01). These results indicate that, in acute ischemia, the pericardium inhibits paradoxical systolic expansion of the ischemic region and increase in end-systolic length of non-ischemic segment. Thus, it is concluded that the pericardium modifies the regional myocardial systolic function in acute ischemia, perhaps through the mechanical restraint of the pericardium.
ZAVOS, P.M., SDFIKITIS, N., TODA, T. and MIYAGAWA, I. Improvements inQualitative Characteristics of Cryopreserved Human Spermatozoa Following Recoveryvia the Use of the SpermPrepTMII Filtration Method. Tohoku J. Exp. Med., 1991, 165 (4), 283-290-Motile, morphologically normal human spermatozoa can be separated from semen via a disposable SpermPrepTM filtration method. This method was employed with great success using frozen-thawed spermatozoa. The present study examined the qualitative characteristics of filtered spermatozoa via a new SpermPrepTMII filtration method in conjunction with the short-term freeze preservation of these spermatozoa. The isolation procedure yielded populations of spermatozoa with very high percentage motility and progressive motility grade (0-4) and which were free of seminal debris. For 20 semen samples the prefreeze values of percentage of motility and grade for the fresh and post-filtered were 58.6% and 3.1 vs 84.1% and 3.6, respectively. The sperm freeze preservation procedure involved dilution of the spermatozoa in Test-Yolk buffer (TYB) with 7% glycerol (v/v) and freezing and thawing in a conventional manner. Post-thaw percent motility, and survival % were substantially higher (p<0.05) for the filtered fraction than for the parent semen. The filtered fractions yielded postthaw mean values of motility percent and grade of 68.9 and 3.4 vs 47.6 and 3.0 for the parent semen, respectively. Survival following incubation at 37°C for 3 hours yielded respective values of 75.9% and 53.2% (p<0.05). It was concluded that the major factor in improving post-thaw quality recovery overall was the filtration via the SpermPrepTMII as applied in this study. This technique could have significant clinical applications in the use of frozen-thawed specimens for noncoital reproduction purposes.
KOMATSU, S., MASUDA, T. and HISAMICHI, S. Effect of Calcium on RatGastric Carcinogenesis Induced by N-Methyl-N'-Nitro-N-Nitrosoguanidine. Tohoku J. Exp. Med., 1991, 165 (4), 291-297-The effect of calcium carbonate (CaCO3) on the initiation of gastroduodenal carcinogenesis induced by N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) was examined under the conditions with and without sodium chloride. Male Wistar rats were given drinking water containing MNNG (100mg/liter) and one of the following diets during the first 20 weeks ad libitum. Group 1 was given basal diet; group 2, diet with 10% NaCl; group 3, diet with 10% NaCl and 2.5% CaCO3; group 4, diet with 10% NaCl and 7.5% CaCO3; group 5, diet with 7.5% CaCO3. During the next 20 weeks, all groups were fed with the basal diet and tap water. The carcinogenic incidences of glandular stomach between the nonsalted diet groups, 1 and 5 (15% and 16% respectively), were not significantly different at the 40th week. The incidences in the salted diet groups 2, 3, and 4 were 59, 63, and 43%, respectively, indicating no statistical difference among them. Thus, CaCO3 showed no anticarcinogenic effect on gastroduodenal carcnogenesis. In the groups 3 and 4, however, increased incidence of duodenal cancer was observed.
NAKAZAWA, I., IWAIZUMI, M. and OHUCHI, K. A Deference in Prostaglandin-producing Ability between Cancer Cells Metastasized into Liver and Kidney. Tohoku J. Exp. Med., 1991, 165 (4), 299-304-In order to study the mechanism of cancer metastasis AH100B cells, a rat hepatoma cell line, were injected into the left carotid artery of male Donryu rats to form metastatic lesions. Each metastatic nodule in the liver and kidney was collected and injected into the peritoneal cavity of normal rats. About 3 weeks later, intact metastatic cancer cells were collected from each ascites that was not bloody. After washing in Dulbecco's phosphate-buffered saline (PBS, Ca2+ and Mg2+-free, pH 7.2), 1×106 cancer cells were incubated in the PBS containing [1-14C]-arachidonic acid (AA ) at 24°C for 5min. AA metabolites formed during the incubation period were extracted and subjected to thin layer chromatography, followed by autoradiography. Each radioactive spot was scraped off the plate and its radioactivity was measured. In the cancer cells which metastasized to the liver, the ability to produce prostaglandin (PG) E2 was higher (p<0.05) but those to produce PGF2α and 6-keto-PGF1α were lower (p<0.01) than in the cancer cells which metastasized to the kidney. These results suggest that cancer cells metastasizing to the liver and the kidney are different from each other in the ability to produce PG.
SHAMSA, F., NAGATA, N., On-ISHI, M. and OHTSUKI, K. The In VitroEffects of Glycyrrhizin and the Derivatives of Glycyrrhetinic Acid on the Activity ofcAMP-Dependent Protein Kinase and Phosphorylation of Cellular Polypeptide bythe Kinase from Ehrlich Ascites Tumor Cells. Tohoku J. Exp. Med., 1991, 165 (4), 305-318-The effects of glycyrrhizin (GL) and the derivatives of glycyrrhetinic acid (GA) on the activity of cAMP-dependent protein kinase (A-kinase) and the phosphorylation of cellular polypeptides by the kinase purified from Ehrlich ascites tumor cells had been investigated in vitro. It was found that (i) the derivatives [3β-hydroxy-olean-11, 13 (18)-diene-30-oic acid Na, olean-9(11), 12 diene-3β, 30-diol-3β, 30-di-o-hemiphthalate 2Na and olean-12-ene-3β, 30-diol 3β, 30-di-o-phosphate 2Na] of GA inhibited the activity of A-kinase at the concentrations higher than 25μM; (ii), at 10μM, these derivatives and native GL stimulated the activity of the kinase significantly; and (iii) the inhibitory and stimulatory effects of some GA derivatives were clearly correlated with their chemical structures. Moreover, sodium dodecyl sulfate polyacrylamide gel electrophoresis and two dimensional gel electrophoresis followed by autoradiography detected several acidic polypeptides, including polypeptides with approximate molecular weights of 35, 000 (pI 4.3), 27, 000 (pI 4.5) and 18, 000-21, 000 (pI 4.5), phosphorylated by A-kinase, to be functioning as mediators in response to these drugs. This observation suggests that the GL-induced inhibition of phosphorylation of these cellular polypeptides by A-kinase may be physiologically implicated in the biochemical mechanisms involved in the anti-inflammatory effect of the drug.