Investigation of the renal injury caused by liver ischemia-reperfusion in rats

To explain the mechanism of renal injury caused by liver ischemia-reperfusion, we investigated biochemical and morphological changes in the liver and kidney in rats. After reperfusion following 60 min of liver ischemia, numerous changes were found. The level of serum transaminases and lipid peroxide formation in the liver tissue increased significantly. Electron microscopic studies revealed that most of the hepatocytes had swollen mitochondria and clumping of the nuclear chromatin. The sinusoidal endothelium was disrupted and the sinusoidal lumen was filled with numerous erythrocytes. Blood endotoxin concentration, plasma lipid peroxide levels, and serum -glucuronidase activities were significantly higher than in the control group. Biochemical and morphological renal injury was also observed. Tissue lipid peroxide levels increased in both the kidney and the liver. Microscopic examination revealed damage to the renal tubules, including interstitial edema, dilatation of the lumen, and granular casts derived from necrotic cells in the proximal convoluted tubule. The levels of urinary N-acetyl--d-glucosaminidase (NAG) in the liver ischemia-reperfusion group were also higher than in the control group. These results suggest that the renal injury was caused by an increase in endotoxin, lipid peroxide, and lysosomal enzymes in the blood following the liver injury induced by the ischemia-reperfusion.     

Efficacy of recombinant human granulocyte-macrophage colony-stimulating factor for chemotherapy-induced leukopenia in patients with non-small-cell lung cancer

To assess the feasibility and efficacy of rhGM-CSF in ameliorating chemotherapy-induced leukopenia in patients with advanced non-small-cell lung cancer, we conducted a double-blind placebo controlled phase III study in a multicenter setting. Patients were eligible if they had cytologically or histologically proven cancer, no prior chemotherapy, stage IIIB or IV disease, an Eastern Cooperativve Oncology Group (ECOG) performance status of 0–2, an age of less than 76 years, and no symptomatic brain metastasis, disseminated bone metastasis, or previous vertebral/pelvic irradiation. The chemotherapy regimen consisted of mitomycin given at 8 mg/m² on day 1, cisplatin given at 100 mg/m² on day 1, and vindesine given at 3 mg/m² i.v. on days 1 and 8 (MVP). If the granulocyte nadir count recorded after the first cycle of MVP was less than 1,000/mm³, patients were randomly assigned to receive recombinant human granulocyte-macrophage colonystimulating factor (rhGM-CSF) or placebo during the second cycle of MVP. The dose of rhGM-CSF was 125 g/m² given daily s.c. for 14 consecutive days starting on day 2. Of the 52 patients enrolled, 45 were evaluable. The nadir of granulocytes was significantly lower in the placebo group (P=0.007). The period during which the granulocyte count was less than 1,000/mm³ was significantly longer in the placebo group (median, 6 vs 10 days;P=0.04). The incidence of adverse effects related to rhGM-CSF, such as fever (38°C) and skin rash, was significantly higher in the rhGM-CSF group (P=0.011). The rate of response to chemotherapy did not significantly differ between the two groups. In conclusion, rhGM-CSF reduced the duration of chemotherapy-induced granulocytopenia. The clinical usefulness of this agent may be deminished because of the adverse effects encountered when it is used in combination with a moderately myelotoxic chemotherapy regimen.Institutions of the BI 71.018 Cooperative Study Group, National Cancer Center Research Institute (N. Saijo, Chairman): Douai Memorial Hospital (Y. Sano), Kanagawa Prefectural Cancer Center (K. Noda), Kantou Teishin Hospital (T. Uzawa), National Medical Center (J. Kabe), Shizuoka Prefectural General Hospital (H. Etou), Teikyo University (K. Mano), Tochigi Prefectural Cancer Center (Y. Saito), Tokyo Geriatric Medical Center (A. Kida), Tokyo Teishin Hospital (T. Morinari), Tokyo Metropolitan Komagome Hospital (S. Kudo), Tokyo Metropolitan Hiroo Hospital (A. Fujikawa), Toranomon Hospital (K. Nakada), Yokohama Municipal Hospital (K. Watanabe), National Cancer Center Central Hospital (K. Eguchi)     

Effect of distance and population size on patient trips in a prefecture of Japan: Application of a transportation distribution model to the demand for and supply of health services

The gravity model, a method for analyzing transportation distribution in transportation engineering, was used to explain patient trips between ten health service regions in a Japanese prefecture. The OD (Origin-Destination) tables were constructed with zoning by regions, distinguishing between out- and inpatients. The observed trips were determined from the data of a survey conducted in 1992 that reported the locations of patient residences and chosen medical facilities. The base values used in the model calculations were the population size of each region and the road distance between the centers of regions. Problems of intrazonal trip were avoided by setting a mean intrazonal movement distance. This model was calibrated by the linear regression method with simultaneous validation by the index of correlation coefficients. The model was found to accurately simulate the effect of distance on the choice of medical facilities and the differences between the characteristics of in- and out-patients. The population value in use showed the relation not only with demand but also the supply of clinical services. It was suggested that the model presented here was useful in the allocation of medical resources and would help explain the relationship between suppliers and consumers of medical services.     

Developmental changes in distribution of death-associated protein kinase mRNAs

Death-associated protein kinase (DAP-kinase) is Ca(2+)/calmodulin-dependent serine/threonine kinase that contains ankyrin repeats and the death domain. It has been isolated as a positive mediator of interferon-gamma-induced apoptotic cell death of HeLa cells. In order to reveal the physiological role of DAP-kinase, the tissue distribution and developmental changes in mRNA expression of DAP-kinase were investigated by Northern blot and in situ hybridization analyses. DAP-kinase mRNA was predominantly expressed in brain and lung. In brain, DAP-kinase mRNA had already appeared at embryonic day 13 (E13) and was, thereafter, detected throughout the entire embryonic period. High levels of expression were detected in proliferative and postmitotic regions within cerebral cortex, hippocampus, and cerebellar Purkinje cells. These findings suggest that DAP-kinase may play an important role in neurogenesis where a physiological type of cell death takes place. The overall expression of DAP-kinase mRNA in the brain gradually declined at postnatal stages, and the expression became restricted to hippocampus, in which different expression patterns were observed among rostral, central, and caudal coronal sections, suggesting that DAP-kinase may be implicated in some neuronal functions. Furthermore, it was found that the expression of DAP-kinase mRNA was increased prior to a certain cell death induced by transient forebrain ischemia, indicating a possible relationship between DAP-kinase and neuronal cell death.     

Anticoagulation after valve replacement: a multicenter retrospective study

Anticoagulant therapy after cardiac valve replacement was evaluated retrospectively in 1,200 patients attending 8 cardiac surgery clinics in the Tokyo area as part of the Tokyo Area Study on Anticoagulation After Cardiac Valve Replacement Using PT-INR (TAS). A prospective trial is also in progress and will be reported later. The prothrombin time international normalized ratio (PT-INR) was determined at the time of thromboembolic and bleeding complications in 1,200 patients. During the 5 year study period, thromboembolisms occurred in 21 patients, and bleeding complications occurred in 15 patients. In 71% of patients with thromboembolism and 47% of those with bleeding complications, the PT-INR was within the range of 1.6 to 2.8, which is the accepted therapeutic range in Japan. Therefore, the correct PT-INR therapeutic range for Japanese patients with mechanical heart valves needs to be reexamined, and data from the prospective TAS trial that is currently underway will be used for this purpose.     

Effect of hydrazine upon vitamin B12-dependent methionine synthase activity and the sulphur amino acid pathway in isolated rat hepatocytes

The effect of the industrial chemical, hydrazine (4-12 mM), on methionine synthase (EC 2.1.1.13) activity and levels of the sulphur amino acids homocysteine, cysteine, and taurine as well as GSH were investigated in vitro in isolated rat hepatocyte suspensions and monolayers in order to explain some of the adverse in vivo effects of hydrazine. None of the concentrations of hydrazine were overtly cytotoxic in hepatocyte suspensions (measured as lactate dehydrogenase [LDH] leakage) after 3 hr. However, after 24 hr in culture cells treated with 12 mM, hydrazine showed a significant increase in LDH leakage. Methionine synthase activity was reduced by hydrazine (8 and 12 mM) in suspensions (by 45 and 55%, after 3 hr) and monolayers (12 mM; 65-80% after 24 hr). This was not due to nitric oxide production and the inhibitor of nitric oxide synthase, Nomega-nitro-L-arginine, failed to protect against the hydrazine-induced loss of ATP and GSH and the reduction in urea synthesis at 24 hr. Homocysteine export was increased by 6 mM hydrazine, and total taurine content of treated cells was increased by 12 mM hydrazine. Thus, hydrazine was found to have several important and possibly deleterious effects on some parts of the sulphur amino acid pathway.     

Effects of ginseng saponins on responses induced by various receptor stimuli

We investigated the effects of four ginseng saponins, ginsenoside-Rb1, -Rg2, -Rg3 and -Ro, on the responses induced by receptor stimulation of various stimuli. Ginsenoside-Rg2 (1-100 microM) reduced the secretions of catecholamines from bovine adrenal chromaffin cells stimulated by acetylcholine and gamma-aminobutyric acid but not by angiotensin II, bradykinin, histamine and neurotensin. In guinea-pig, the ginsenoside also diminished the nicotine-induced secretion of catecholamines from the adrenal chromaffin cells, but it did not affect the muscarine- and the histamine-induced ileum contractions. On the other hand, ginsenoside-Rg3 (1-100 microM) reduced not only the acetylcholine-, the gamma-aminobutyric acid- and the neurotensin-induced secretions but also, at a higher concentration (100 microM), the angiotensin II-, the bradykinin- and the histamine-induced secretions from the bovine chromaffin cells. Furthermore, the saponin (3-100 microM) significantly inhibited the muscarine- and the histamine-induced ileum contractions of the guinea-pig. Ginsenoside-Rb1 and -Ro had no marked effect on their responses. These results strongly suggest that ginsenoside-Rg2 is a potent selective blocker of nicotinic acetylcholine and gamma-aminobutyric acid receptors (ionotropic receptors) and ginsenoside-Rg3 is not only a blocker of ionotropic receptors but also an antagonist of muscarinic or histamine receptors.     

Purification and characterization of 2-deoxy-scyllo-inosose synthase derived from Bacillus circulans. A crucial carbocyclization enzyme in the biosynthesis of 2-deoxystreptamine-containing aminoglycoside antibiotics.

The biosynthesis of 2-deoxystreptamine, the central aglycon of a major group of clinically important aminoglycoside antibiotics, commences with the initial carbocycle formation step from D-glucose-6-phosphate to 2-deoxy-scyllo-inosose. This crucial step is known to be catalyzed by 2-deoxy-scyllo-inosose synthase, which has not yet been characterized so far. Reported in this paper is the first purification of 2-deoxy-scyllo-inosose synthase from butirosin-producing Bacillus circulans SANK 72073 to electrophoretic homogeneity. The enzyme was isolated as a heterodimeric protein comprising from a 23 kDa- and a 42 kDa polypeptide chains. The Km of the enzyme for D-glucose-6-phosphate was estimated to be 9.0 x 10(-4) M and that for NAD+ 1.7 x 10(-4) M, kcat for D-glucose-6-phosphate being 7.3 x 10(-2) s(-1). The presence of Co2+ was essential for the enzyme activity, but Zn2+ was totally inhibitory. While the reaction mechanisms are quite similar, 2-deoxy-scyllo-inosose synthase appears to be distinct from dehydroquinate synthase in the shikimate pathway, with respect to the quaternary structure, metal ion requirement, and the kinetic parameters.     

A case of drowning linked to ingested sulfides — a report with animal experiments

An adult male was found dead beneath a pool of sewage in the pump room of a fish market. Autopsy revealed the cause of death to be suffocation after aspirating sewage into the respiratory tract. Since hydrogen sulfide gas was detected in the atmosphere at the scene of the accident, gas poisoning was suspected and toxicological analysis of sulfides in body tissues was performed. The concentrations of sulfides in the blood, lung and kidney were 0.95 mol/ml, 0.22 and 0.38 mol/g, respectively. These values were remarkably higher than those in previously reported cases involving exposure to hydrogen sulfide gas. Therefore, oral intake of sulfides was assumed and the distribution of sulfides in tissues following oral administration of sodium sulfide solution was examined by means of animal experiments using rats. The concentration of sulfides in the blood from rats following oral intake was much higher than that seen following gas exposure. Based on these results, we concluded that the victim had been exposed to hydrogen sulfide gas and had then collapse into a pool of sewage containing sulfides. The sulfides which were distributed throughout the body tissues had mainly issued from the alimentary tract prior to death by drowning.