Nihon juigaku zasshi. The Japanese journal of veterinary science最新文献

To investigate whether adult heartworms harboring in the pulmonary arteries contribute to pulmonary hypertension, we determined the cardio-pulmonary values immediately before and after removal of heartworms from the pulmonary arteries and before and after insertion of live worms in their place. In 10 heartworm-infected dogs, 8 to 46 worms were removed. The mean pulmonary arterial pressure fell significantly from 24.5 +/- 7.9 mmHg to 16.3 +/- 4.9 mmHg (p less than 0.01) immediately after removal. The right cardiac output decreased in 7 of the 10 cases. The total pulmonary resistance and right ventricular stroke work index also decreased. At 24 hours after removal, live heartworms were put back into the pulmonary arteries of their host dog. The mean pulmonary arterial pressure elevated significantly (p less than 0.01) immediately after insertion. The right cardiac output further decreased in 7 of the 10 dogs, and the total pulmonary resistance and right ventricular stroke work index increased. Separate from this, 12 to 42 heartworms were transplanted into the pulmonary arteries of 5 heartworm-free dogs. Immediately after transplantation, the pulmonary arterial pressure did not show any significant change. However, the stroke volume decreased, and the total pulmonary resistance increased. These facts suggest a contribution of live heartworms to the pulmonary hypertension, although there is a complicated interaction among the presence of heartworms, the pulmonary lesions and the pulmonary hypertension.

A triangular wave microelectrode oscillating apparatus was constructed to evaluate an intracellular recording of rat neuron activity in the medial preoptic area (POA) of the hypothalamus. In this apparatus, electrodes passed a current with a frequency of 1.0 to 1.8 kHz and a voltage of 2.2 to 3.2 V and produced micro-oscillation of the electrode tip. The electrode was inserted into a neuron of the rat POA in vivo. In vivo recording of the activity of the rat POA neuron was possible. By means of electrical stimulation of the median eminence arcuate of the hypothalamus, an intracellular recording of antidromic, orthodromic or non-responding neuron was also possible. As a result, various components of the action potential such as the resting, threshold and spike potentials, and depolarization and repolarization such as after-hyperpolarization and after-depolarization were observed. The resting potentials ranged from 45 to 90 mV, and POA neurons possessed action potentials of almost the same magnitude. Several problems, however, remain to be solved. In general, the time available for the intracellular recordings is too short. The cells survive only for 15 minutes at the longest and may die in only a few minutes. An improvement of the apparatus was mandatory.

Fecal samples (2,019) from cattle in the university farm, Tohoku University, were examined for coccidian oocysts from April 1986 to January 1987, and 19.3% of them was positive for Eimeria spp. Thirteen Eimeria species were identified. Eimeria bovis (25.7%) was the most dominant species, followed by E. auburnensis (17.6%), E. canadensis (14.5%), E. alabamensis (9.7%), E. ellipsoidalis (8.1%), E. zuernii (7.0%), E. bukidnonensis (5.4%), E. brasiliensis (3.9%), E. cylindrica (1.3%), E. illinoiensis (0.4%), and E. pellita (0.2%). Fecal samples positive for coccidial oocysts amounted to 12.9% and 26.7% on average during grazing on pasture and loose housing, respectively.

A total of 500 fecal droppings of crows collected from a seashore of an ocean bay and from a cemetery on a hill surrounded by a forest were examined for thermophilic campylobacters, and the Skirrow's biovars and Penner's serogroups of the isolates were determined. The organisms were isolated from 169 (62.6%) of 270 seashore crow samples and 106 (46.1%) of 230 cemetery crow samples. During the investigation period from May 1986 to April 1987, the monthly isolation rate of thermophilic campylobacters in the seashore crow varied from 32.0 to 85.0%. C. jejuni, C. coli, and C. laridis were isolated from 150, 21 and 14 samples, respectively. In case of the cemetery crow, the monthly isolation rate varied from 20.0 to 75.0%, and C. jejuni, C. coli, and C. laridis were detected from 80, 12 and 16 samples, respectively. Among 192 strains of C. jejuni selected from 98 seashore and 57 cemetery crow samples, 106 (93.0%) of 114 seashore crow strains and 69 (88.5%) of 78 cemetery crow strains were identified as Skirrow's biovar I. Of 192 strains of C. jejuni serogrouped, 169 strains were classified into 20 serogroups. The Penner's serogroup 2, one of common serogroups among poultry and human isolates in Japan, was the most predominant in crow strains.

The characteristics of developing intraerythrocytic stages of T. sergenti were studied by light and transmission electron microscopy. The parasites with many ribosomes, acristate mitochondria, cytostome, and food vacuoles were morphologically regarded as the trophozoite stage. Although this type of parasites was frequently detected, intraerythrocytic merozoite stage with electron dense cisternae, rhoptries and small electron dense bodies was rarely observed in high parasitaemia. The intraerythrocytic stages of T. sergenti were divided mainly into four daughters by schizogony, and alternatively into two by binary fission. The daughter parasites in each division had the same ultrastructural features as of merozoites. As a result, it was suggested that T. sergenti trophozoites multiplied by schizogony to four organisms or by binary fission in the peripheral erythrocyte, and differentiated to the merozoites which acquired penetrating ability into the erythrocytes.