Oxygen consumption for constant work is minimal at lowest working contractility in normal dog hearts

We tested whether minimal myocardial oxygen consumption (MVO2) for a given external work would exist in the middle of a normal contractility range as previously predicted theoretically. The left ventricle of the excised cross-circulated dog heart preparation was connected to a volume servo pump. Myocardial contractility in terms of ventricular end-systolic elastance (Emax) was gradually increased from control 8.9 +/- 3.4 (mean +/- SD) to 30.0 mmHg/(ml/100 g) by epinephrine and decreased to 1.8 mmHg/(ml/100 g) by propranolol while heart rate, end-systolic pressure and stroke work were kept constant. MVO2 was determined as the product of total coronary flow and coronary arteriovenous oxygen content difference in each contractile state. We plotted MVO2 values against E(max) values in each heart. The MVO2-E(max) relation for a constant cardiac work showed that MVO2 was minimal at the low end of the covered E(max) range. We conclude that minimal MVO2 for a given cardiac work is generally obtained at the lowest working contractility in normal dog hearts. This conclusion might pose some problems in the previous theoretical prediction as to the contractility that achieves the minimal MVO2 in a given external work.     

Subacute toxicity of piperonyl butoxide in ICR mice

Piperonyl butoxide, alpha-[2-(2-butoxyethoxy)ethoxy]-4,5-methylenedioxy-2-propyltol uene, is a pesticide synergist. ICR mice of both sexes were maintained on diet containing 0, 0.1, 0.3 or 0.9% of piperonyl butoxide for 20 days. At the end of the experimental period, they were necropsied. Selected organs were weighed and serum chemistries were analyzed. In male and female mice of the 0.9% group, body weight, kidney and spleen weight were depressed in comparison to those of control group. Liver weight of the 0.3 and 0.9% group of both sexes were significantly higher than those of control group. Mice of the 0.9% group of both sexes had increased serum levels of cholesterol, total protein, gamma-glutamyl transpeptidase. Histological examination of livers from mice of the 0.9% group by light microscopy showed enlarged hepatocytes, anisonucleosis and single cell necrosis. The results indicated that subacute toxicity of piperonyl butoxide in ICR mice was directed primarily at liver.     

Effect of sodium nitroprusside on compound action potential thresholds in the gerbil cochlea

OBJECTIVE: Trials that do not allow rejection of the null hypothesis of no treatment effect may have had an inappropriate design. Trials are virtually never assessed for correlation between responses to different treatment modalities. METHODS: Using a hypothetical example and several published studies we examine the influence of correlation levels between treatment modalities on the sensitivity of testing. RESULTS: The level of correlation between responses to different treatment modalities is a major determinant of the sensitivity both of crossover and parallel group clinical trials. CONCLUSIONS: It is very relevant to assess a priori correlation levels between responses to the different treatment modalities of a trial. If a negative correlation is anticipated, a crossover design is likely to lack sensitivity. If a positive correlation is anticipated a parallel-group design seems less appropriate, because it would lack the extra sensitivity of accounting for the positive correlation. Both designs would seem suitable for approximately zero correlations (e.g. comparison vs baseline or vs placebo under the assumption that the number of placebo responders is negligible.     

Acquired autoimmune thrombocytopenia post-bone marrow transplantation for severe combined immunodeficiency

Children with severe combined immunodeficiency (SCID) have profoundly diminished humoral and cellular immunity resulting in death during infancy unless immune reconstitution occurs by bone marrow transplantation (BMT). Thrombocytopenia post-bone marrow transplantation can be seen in relation to infection, graft-versus-host disease (GVHD) and rarely, as an autoimmune phenomenon due to immune dysregulation. We report two cases of severe AITP following BMT for SCID. Both cases developed large intracerebral hemorrhages from which one died. Autoimmune thrombocytopenia in this setting can be life-threatening and we recommend early and active intervention.     

Development of `information collection and delivery sensor basesystem' for large-scale power systems

The authors present a real-time database system capable of collecting and delivering a large amount of information accurately at a high speed and by a simple method. This system has a microprocessor unit (MPU) for each private communication line around the main memory and coordinates the independent parallel operation for a number of these MPUs with the main memory access operation, using a fixed cyclic scan method and having all the MPUs perform multi-operation. Many advantages can be expected when this method is adopted, especially for the monitoring and control of power systems. Degradation of the system can be avoided during an information rush due to accidents, and it can be easily extended when adding to or expanding the power facilities in the future. Excellent daily maintainability can be assured, and a low overall cost can be expected     

Fractal dimension of the grain boundary fracture in creep-fracture of cobalt-based heat resistant alloys

The effects of grain boundary configuration and creep conditions on the fractal dimension of the grain boundary fracture (D _f) were investigated using commercial cobalt-based heat resistant alloys, namely, HS-21 and L-605 alloys. Creep-rupture experiments were carried out under the initial creep stresses of 19.6–176 MPa in the temperature range from 1089–1422 K in air. The value of D _f was larger in specimens with serrated grain boundaries than in those with straight grain boundaries in the HS-21 alloy under the same creep condition, and the difference in the value of D _f between these specimens was large in the scale range of the analysis which was less than about one grain boundary length. However, there was almost no difference in the value of D _f between the specimens with serrated grain boundaries and those with straight grain boundaries in the L-605 alloy, because there was no obvious difference in the microstructure between these specimens. The value of D _f increased with decreasing creep stress in the scale range of the fractal analysis larger than about one grain boundary length in both HS-21 and L-605 alloys, while the stress dependence of D _f was larger in the HS-21 alloy. The stress dependence of D _f was explained by the stress dependence on the number of grain boundary microcracks linked to the fracture surface. The value of D _f estimated in the scale range smaller than about one grain boundary length showed essentially no stress dependence in both L-605 and HS-21 alloys.