The effects of metabolic acidosis and alkalosis in the initial reperfusate on post-ischemic stunned myocardium were investigated in isolated rat hearts. Metabolic acidosis and alkalosis were produced by altering the doses of artificial buffer (Tris) in place of sodium bicarbonate. All hearts were subjected to global ischemia for 15 min at 37 degrees C. The initial reperfusate under study was given during the subsequent 10 min of reperfusion, just prior to release of the aortic clamp. After that, reperfusion using normal Krebs-Henseleit buffer solution was carried out for 40 min. The acidotic initial reperfusate (pH 6.8) resulted in better protection than the alkalotic initial reperfusate (pH 7.8), as demonstrated by 1) a higher recovery of aortic flow (80.6% +/- 3.8% vs 32.7% +/- 4.8%, p less than 0.01), 2) a smaller leakage of creatine kinase during the initial reperfusion phase (6.0 +/- 0.7 vs 14.6 +/- 2.1 IU/10 min/g dry weight, p less than 0.05) and during the post-ischemic Langendorff perfusion phase (8.8 +/- 1.7 vs 37.3 +/- 5.2 IU/10 min/g dry weight, p less than 0.05), and 3) a lower myocardial water content at the end of reperfusion (84.8% +/- 0.2% vs 85.7% +/- 0.3%, p less than 0.05). Not only Tris buffer system, but also HEPES buffer system indicated that acidotic initial reperfusate was effective to protect against myocardial injury. These results suggest that 1) the extracellular pH during initial reperfusion profoundly influences the reversible myocardial dysfunction (stunned myocardium), and 2) the acidotic initial reperfusate improves post-ischemic myocardial performance.

Acidosis↗

PubMedDate not supplied

Epidemiologic studies of lung disease due to mycobacteria other than Mycobacterium tuberculosis in Japan.

The incidence of lung disease due to mycobacteria other than Mycobacterium tuberculosis (atypical mycobacteria) in Japan was estimated to be 0.9--1.9 per 10(5) population per year in 1971--1979. Although the incidence of lung tuberculosis is steadily decreasing, the incidence of lung disease due to atypical mycobacteria has remained at almost the same level. The number of patients newly infected per year in recent years was calculated to be approximately 2,000. The ratio of the number of patients with lung disease due to atypical mycobacteria to the number of patients with lung disease due to atypical mycobacteria to the number of patients with lung disease due to all species of mycobacteria was highest in hospitals on the southwest coast of the Pacific. The atypical mycobacteria that caused disease most frequently belonged to the Mycobacterium avium-intracellulare complex. Of the 537 cases of disease due to atypical mycobacteria, 491 (89.6%) were due to these organisms; 43 (8.0%), to Mycobacterium kansasii; and 7 (1.3%), to Mycobacterium fortuitum. The disease due to M. kansasii appeared most frequently in hospitals in the Tokyo and Kanagawa prefectures. Patients with lung tuberculosis had a high risk of lung infection due to M. avium-intracellulare. The incidence of such disease in tuberculous patients was estimated to be 18.7 per 10(5) population per year, a rate that is approximately 10 times that found in the general population.

Humans↗

PubMedDate not supplied

Technical evaluation of oxygen transfer rates of fish gills and artificial gills.

An artificial gill, which takes oxygen from water, would enhance the ability of people to function under water for extended periods. Increasing oxygen transfer rate, however, would be essential to the realization of compact, commercially viable equipment. Fish have evolved a variety of techniques to enable them to breathe under water, and their mechanisms must be clarified before compact, high-performance artificial gills can be developed. A model of the secondary lamellae of fish gills, through which oxygen is taken up from water to the blood, was devised, and its structure and oxygen transfer rate were evaluated by computer simulation analysis for carp and dogfish. Oxygen transfer rates were also found for an outside-water-flow artificial gill using a hollow fiber membrane at various fiber packing ratios. The biologic membrane is rate-determining for oxygen transfer through the secondary lamellae. Blood and water side boundary film resistances are small for fish because the blood and water channels are very narrow and numerous. When the fiber packing ratio of the artificial gill is raised, the oxygen transfer rate increases because of lower water side boundary film resistance. An optimum fiber packing ratio should be selected so that there is no major increase in pressure drop and no channeling occurs.

Animals↗

PubMedDate not supplied

Oral findings in Johanson-Blizzard syndrome.

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Anodontia↗