Heritability estimates of liabilities to digestive diseases in heavy racehorses

Data on 1410 heavy racehorses were taken from the Hokkaido Banei Horse Racing Result Book published during 1997–2000. Heritabilities were estimated using the restricted maximum likelihood method with a full data set of the accumulated prize winnings and the frequency of medical treatment against digestive diseases. Heritability estimates for the same traits were also obtained using a partial data set from affected animals only. In addition, a ‘two classes, one threshold’ model was applied to the full data set for the heritability estimation of liability to the diseases. Heritabilities estimated by restricted maximum likelihood with the full data set were quite low: 0.09 ± 0.02 for the prize winnings and 0.08 ± 0.03 for all three digestive diseases – colic resulting from flatulence, constipation and overfeeding. Low heritabilities were also estimated for each of the three kinds of colic. Medium heritabilities were estimated for colic resulting from constipation (0.30 ± 0.19) and overfeeding (0.46 ± 0.22) using the partial data set taken from the affected animals. Using the threshold model, higher heritabilities from 0.42 ± 0.04 to 0.57 ± 0.03 were estimated for the liabilities to all three digestive diseases and to the individual digestive diseases. These results suggest that liability evaluation of the frequency of medical treatment is insufficient because all non‐affected animals are scored as 0. The high heritabilities estimated by the threshold model with half‐sib relationships should be verified in future studies by comparing them with estimates from other genetic relationships and with realized heritabilities from a small‐scale practical selection program.     

Cellular compartmentation and membrane permeability to sugars in relation to early or high temperature-induced watercore in apples

Early watercore was observed in apples (Malus domestica Borkh.) from the outer canopy of ‘Orin’, an early watercore susceptible cultivar, while there was no watercore in ‘Orin’ fruit from the inner canopy and resistant ‘Fuji’. Sorbitol content was higher not only in the free space but also in the vacuole and cytoplasm in watercored ‘Orin’ than in other non-watercored fruit. Comparing watercored apples to non-watercored fruit of ‘Orin’, higher fructose and glucose in the vacuole and no significant difference in the distribution rate of sorbitol to each compartment were observed. Watercored ‘Orin’ apples showed significantly higher permeability of tonoplast to fructose, glucose, and sorbitol than those in other non-watercored apples. The permeability of plasma membrane to each sugar was much higher than that of tonoplast but no marked difference was observed among the treatments. The results suggest that metabolism of sorbitol could be active even in watercored ‘Orin’ apples and the accumulated sorbitol in the intercellular spaces might be primarily due to an active unloading from the phloem and not be brought by increased leakage from the cells.     

A retrospective study on adverse reactions to canine vaccines in Japan

Adverse reactions to vaccines were examined in 311 canine cases reported to the Ministry of Agriculture, Forestry and Fisheries in Japan during the period of 6 years from April of 1994 to March of 2000, and classified according to their clinical symptoms. There were 27 cases of adverse reactions to rabies virus vaccines. Gastrointestinal symptoms were the most frequently observed (26%), followed by respiratory and/or cardiovascular symptoms (22%) and dermatologic symptoms (11%). There were 284 cases of adverse reactions to non-rabies monovalent vaccines and mixed vaccines. Dermatologic symptoms were the most frequently observed (53%), followed by gastrointestinal symptoms (16%) and respiratory and/or cardiovascular symptoms (14%). Of the total 311 cases, 11 (3.5%) died of adverse reactions to vaccines.     

Omental herniation through the esophageal hiatus in a cat

A four-year-old male cat was presented with regurgitation. Thoracic radiography and contrast radiogram showed a large oval mass and elevated esophagus. Exploratory thoracotomy showed omental herniation into the posterior mediastium through the esophageal hiatus. Because the mass of the omental herniation was so large, celiotomy through a paracostal incision was combined in order to return the omentum to its normal position. The diameter of the esophageal hiatus was approximately 1 cm but no fibrous adhesion was observed around the hiatus. Continuous 1-0 surgical sutures on the hiatus reduced the diameter of the hiatus. The cat made a successful postoperative recovery without complications.     

Novel variations and loss of heterozygosity of BRCA2 identified in a dog with mammary tumors

OBJECTIVE: To establish novel polymorphic markers for analysis of loss of heterozygosity (LOH), so as to study the possible involvement of BRCA2 in mammary tumors obtained from dogs. SAMPLE POPULATION: Blood samples, mammary gland specimens, or mammary tumors from 3 tumor-bearing dogs and 10 tumor-free dogs. PROCEDURES: Nucleotide sequence analysis was performed with a DNA autosequencer. Loss of heterozygosity analysis was performed for markers established in the present study. The expression level of canine BRCA2 was quantified by real-time PCR analysis. RESULTS: 3 novel microsatellite markers with high heterozygosity rates (> 50%) were established, and the previously reported marker for canine BRCA2 gene locus was improved. These markers were used for the analysis of DNA from formalin-fixed and paraffin-embedded samples. By use of these markers, LOH in canine BRCA2 was identified as a result of recombination. In mammary tumor DNA that corresponded to the LOH-positive dog, the level of canine BRCA2 expression was decreased compared with that of nonneoplastic mammary gland tissue; the open reading frame contained 4 missense variations, 1 insertion variation, and 1 silent variation, some of which were localized to functional domains. CONCLUSIONS AND CLINICAL RELEVANCE: 3 novel polymorphic markers were developed for LOH analysis of canine BRCA2 and identified a dog with LOH with some variations in the functional domains. These markers could be useful for assessing the relevance of BRCA2 variation in mammary tumors of dogs.     

A pre-harvest method for predicting understory light levels created by artificial canopy gaps

A new method for predicting understory light levels around an artificial canopy gap prior to the selective cutting is presented. In two even-aged coppice stands, hemispherical photographs were taken at a height of 1.3 m, and crowns of each canopy stem on the photographs were identified by field observations. To predict light levels after cutting, we used computerized images of the hemispherical photographs, in which we digitally erased all crowns to be cut (named ‘erasing method’). Light levels were calculated by an analyzing program; HEMIPHOT. Light levels predicted by the ‘erasing method’ were compared with that calculated by the ordinary photograph-analyzing method using photographs taken after the actual cutting. The correlations between the two methods were highly significant in the two stands. The ‘erasing method’ is eminently effective for the prediction of understory light levels in an artificial canopy gap.     

Pulmonary atherosclerosis and pulmonary arterial pressure in cholesterol-fed New Zealand white rabbits.

The lung produces many vasoactive substances originating from its vascular endothelium and plays an important part in various pathose. The present study was carried out to clarify pulmonary atherosclerosis and pulmonary arterial pressure, and to elucidate a part of the pulmonary pathosis in cholesterol-fed rabbits. Atherosclerosis was induced by feeding the animals a cholesterol-rich diet. When the rabbits were fed the cholesterol-enriched diets for 15 weeks, the grade of the atherosclerosis was severer than in 8W-feeding rabbits. The lesions of 8W-feeding rabbits were mainly composed of foam cells and fibrous components, whereas in 15W-feeding rabbits, the aggregation of foam cells beneath the endothelium of the vessel was infiltrating the media and severe stenose of the lumen was observed. In the entire pulmonary arterial system, the severe obstructive vascular lesions were localized and not diffused. The pulmonary arterial pressures of the rabbits increased slightly with time and the mean pressures were 11.3+/-0.9 (control group), 11.8+/-1.0 (8W group) and 13.7+/-1.5 mmHg (15W group) respectively. A significant difference existed in the mean pressure between the control group and 15W-feeding group, but there were no significant differences in the systolic and diastolic pressures among the three groups. In conclusion, we could induce pulmonary atherosclerosis in rabbits by feeding them a hyper-cholesterol diet but not overt pulmonary hypertension.