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Biomedical subjects

T Morozumi

Publications and source records attributed to T Morozumi.

60 records · Page 4Linked to original sources

Effect of temperature on the survival of Haemophilus parasuis in physiological saline.

The survival of Haemophilus parasuis in physiological saline and in sodium phosphate buffered saline (PBS) at various temperatures was investigated and compared with that of H. pleuropneumoniae, Pasteurella multocida, and Escherichia coli. When placed in physiological saline, H. parasuis became undetectable at 42 degrees C within one hour, at 37 degrees C within 2 hours, and at 25 degrees C within 8 hours, but decreased slightly in amount at 5 degrees C for 8 hours. It showed the same tendency when placed in PBS. In the same condition, H. plueropneumoniae decreased more slowly in amount than H. parasuis, P. multocida was much more stable than H. parasuis, and E. coli hardly decreased even at 42 degrees C for 8 hours.

Culture Media↗

Experimental infections of mice and guinea pigs with Haemophilus parasuis.

The pathogenicity of Haemophilus parasuis for mice and guinea pigs was examined. Mice were inoculated intraperitoneally with 2 X 10(7) to 2 X 10(9) organisms suspended in saline or in broth containing fresh yeast extract. Most of them survived after inoculation. Death occurred only in mice inoculated with 2 X 10(9) organisms suspended in broth. The recovery rate of H. parasuis from all the dead mice varied from 28.9% of the brains to 71.4% of the lungs. There were no lesions observed in any mouse, except one. Guinea pigs were inoculated intraperitoneally with 1 X 10(8) to 1.6 X 10(10) organisms suspended in saline. Many of them died after showing septicemia and serofibrinous serositis, which were associated with purulent leptomeningitis or meningoencephalitis in some of them. H. parasuis was recovered abundantly from many organs, including the brain, in the guinea pigs. It was also recovered from guinea pigs inoculated with 1.8 X 10(9) organisms by various routes. Serositis was observed in guinea pigs inoculated intramuscularly or intrapulmonarily. These results suggested that guinea pigs might be available for investigation of the pathogenicity of H. parasuis.

Animals↗

Glässer's disease in piglets produced by intraperitoneal inoculation with Haemophilus parasuis.

Haemophilus parasuis was inoculated into the abdominal cavities of piglets. Its infective doses varied from 1.4 X 10(6) to 1.0 X 10(9) organisms. When inoculated with 1.0 X 10(9) or 1.6 X 10(8) organisms, piglets were affected with fibrinous polyserositis associated with arthritis and purulent meningitis. The three disorders were considered to be characteristic of Glässer's disease. Septicemia was also found in many of the infected piglets, some of which died within a few days after inoculation. No lesions were observed in piglets inoculated with 1.4 X 10(7) or 1.4 X 10(6) organisms. It was difficult to reisolate H.parasuis from lesions, especially those in the abdominal cavities of piglets killed on the 6th day after inoculation. Agglutinating and complement-fixing antibodies were present in the piglets with Glässer's syndrome examined on the 6th day after inoculation. Neither of them was detected in any piglet manifesting no clinical signs, except transient pyrexia.

Animals↗

Effect of beta-blockade on regional left ventricular function in patients with dilated cardiomyopathy.

It has been reported that beta-blockade has beneficial effects on the cardiac function and prognosis of patients with congestive heart failure. However, the mechanism for these effects remained unclear. This study compared the use of an angiotensin-converting enzyme (ACE) inhibitor (enalapril, 2.5 to 5.0 mg/day, or delapril, 15 to 30 mg/day) alone with the effects of beta-blockade therapy (metoprolol, 40 to 60 mg/day) coupled with an ACE inhibitor on global and regional left ventricular (LV) function in patients with dilated cardiomyopathy. In 12 patients with dilated cardiomyopathy, the global LV ejection fraction (EF), regional EF (rEF), and regional ejection time (rET) were determined by sector analysis of the radionuclide ventriculogram before and after therapy (duration 14 +/- 9 months). The coefficients of variation of rEF and rET were calculated as indexes of the heterogeneity of regional LV systolic wall motion. EF increased significantly from 20% +/- 8% to 30% +/- 8% (p < 0.05) in patients who received beta-blockade and an ACE inhibitor (n = 5). Furthermore, the coefficients of variation of rET decreased from 27% +/- 13% to 16% +/- 7% (p < 0.05). In contrast, patients treated with an ACE inhibitor only (n = 7) showed no significant improvements in any of these parameters. These results suggest that, compared with an ACE inhibitor alone, beta-blockade improves global and regional LV function in dilated cardiomyopathy by synchronizing myocardial contraction.

Adrenergic beta-Antagonists↗