High-resolution computed tomography of the mammalian lung.

High-resolution computed tomography (HRCT) was performed in 21 isolated animal lungs, from 4 mammalian species (pigs, rabbits, dogs, sheep). Gross and subgross central and peripheral lung morphology was determined by HRCT. Three distinct types of lungs can be identified, principally based on the extent of interlobular septal development; the relationship of major vessels to airways; and the thickness of the visceral pleura. Type-I lung is found in pigs, sheep, and cattle; type-II lung is found in rabbits, dogs, cats, and monkeys; and type-III lung is found in human beings and horses. These mammalian lungs were compared with human lungs. The potential use of HRCT to investigate specific human lung diseases in the aforementioned species also was considered.     

Effect of initial restraint, weaning, and transport stress on baseline and ACTH-stimulated cortisol responses in beef calves of different genotypes.

The productivity and well-being of animals can be substantially affected by stress. This is particularly true in the case of beef calves that are subjected to a multitude of stressors over a short period during the first year of life. Perhaps the most often studied stress-responsive variable has been blood corticosteroid concentrations. Factors such as age, gender, genetics, and degree of prior experience, can influence how an animal perceives and responds to a given stressor. Few studies have tried to control these variables, and accordingly, many conflicting results have been published regarding the impact of various stressors on cortisol response. We measured baseline plasma cortisol concentration over a 44-day study in Bos indicus and Bos taurus calves. Plasma cortisol values in Bos indicus calves were higher (32.60 +/- 0.66 ng/ml) than values in calves of Bos taurus (25.81 +/- 0.76) breeding. A precipitous decrease in cortisol concentration was observed 7 days after transport stress in all calves. Baseline cortisol concentration did not provide any indication of the intensity of the various stressors. However, significant differences were readily observed after ACTH administration. On the basis of cortisol secretion, stresses of transport and weaning were similar and were the most stressful to calves, regardless of genotype.     

Dinoseb toxicosis in two dogs

Two male English Setters were noticed to be breathing rapidly, hyperexcitable, and atactic after roaming a rural area for 2 hours. Both dogs' cost were stained with yellow liquid. One dog died while en route to the veterinarian. Treatment was begun for the surviving dog for what was initially diagnosed to be organophosphorus or carbamate insecticide toxicosis. Before the diagnosis could be confirmed, the second dog died. The yellow liquid on the dogs' skin was identified as dinoseb in high concentrations. Dinoseb is an acutely toxic, substituted dinitrophenolic herbicide believed to act as an uncoupler of electron transport from oxidative phosphorylation.     

Infection of Cherax quadricarinatus (Decapoda: Parastacidae) by the microsporidium Thelohania sp. (Microsporida: Nosematidae)

Abstract The microsporidian parasite Thelohania sp. was present in a population of Cherax quadriearinatus in the Mitchell River, north Queensland. An infection rate of 7--8% was recorded for the population sampled. Cohabitation, passage of spores through fish, ingestion of spores and injection of blood from an infected individual failed to elicit infection in laboratory held animals. Injection of spores elicited a host responseconsisting of encapsulation and melanization of spores. Further studies are necessary to clarify the taxonomic position and mode of transmission of this parasite.     

Genomic variability among globally distributed isolates of equine arteritis virus.

Equine arteritis virus (EAV), a non-arthropod borne togavirus, has been shown to have a global distribution. To date, no major antigenic variation has been demonstrated between EAV isolates from different geographic origins. In this study, the genomic RNA of EAV isolates obtained from horses of different breeds in various countries around the world was oligonucleotide fingerprinted. Comparisons of these fingerprints were used to determine the extent of genomic variation among such isolates. Comparisons among isolates from North American horses revealed, for the most part, oligonucleotide homologies of less than 60%. Only 29 of the 98 comparisons revealed greater than 60% oligonucleotide homology. Nonetheless, several comparisons indicated a close epidemiologic relationship between isolates from horses of different breeds located in different states. Though all European isolates were of Standardbred origin and were from horses located in northern European countries, the majority had oligonucleotide homologies of less than 60%. Where oligonucleotide homology was apparent, it was, with one exception, greater than 70%. The two isolates from New Zealand had 93.2% oligonucleotide homology. This is indicative of an extremely close epidemiologic relationship. Comparisons between EAV isolates from around the world revealed oligonucleotide homologies between viruses from North America, Europe and New Zealand. In several instances, this homology was greater than 70% and in one case greater than 80%. No oligonucleotide homology was evident in comparisons involving the virus from South Africa. The high level of genomic conservation between certain EAV isolates of disparate geographic origins may reflect dissemination of the virus associated with the international movement of horses. The extent of genomic variation demonstrated between most of the EAV isolates used in this study confirms the need for further investigation of genomic heterogeneity among strains of this virus before techniques that rely upon nucleic acid hybridization can be effectively applied as diagnostic procedures.     

Toxic peripheral neuropathy with demyelination in Sprague-Dawley rats given CGS 21595--a 5-lipoxygenase inhibitor.

Male and female Sprague-Dawley rats were given CGS 21595, a pro-drug that is almost immediately metabolized to CGS 19213, a naphthoquinone that acts as a 5-lipoxygenase inhibitor. The compound was administered by gavage to five groups of Sprague-Dawley rats (group Nos. 1, 5, n = 30; group Nos. 2-4, n = 20) at daily doses of 0, 50, 150, 500, or 1,000 mg/kg for 13 weeks. Rats in the higher dose groups had a reduced weight gain, but significant neurologic signs were not observed. A peripheral neuropathy consisting predominantly of myelin destruction in the spinal nerve roots and sciatic nerves in male rats treated with greater than or equal to 150 mg/kg CGS 21595 and in female rats treated with greater than or equal to 50 mg/kg CGS 21595 for 13 weeks. This lesion was not fully reversible after a recovery period of 4 weeks. Lesions consisted of ballooning of myelin sheaths, infiltration by macrophages, demyelination, and occasional areas of remyelination. Axons were generally preserved, and the brain and spinal cord were not affected. Male and female rats in all treatment groups had cytoplasmic hyaline droplets in the proximal renal tubules. This change was reversible after 4 weeks and was not associated with any other adverse effects on the kidney.     

鸭瘟病毒的PCR检测及其产物分析

根据基因库中已有的鸭瘟 Ul6的序列 ,合成一对引物 ,对 3株鸭瘟病毒进行 PCR扩增 ,均扩增出大小约 42 0 bp的特异性片段。进行测序 ,结果表明 3个毒株扩增后的片段均为 42 1bp。经重复实验后确定最佳反应条件 ,按该条件对两例临床病料进行检测 ,结果均出现大小约为 42 0 bp的特异片段。PCR产物与 L ake Andes株的相关序列比较 ,广东毒株与 L ake Andes株同源性较高     

家蚕豆腐渣人工饲料及五龄期饲育研究

以３个栽培品种的冬芽为试验材料，分析了茎尖培养生长差异的生理原因．结果表明：添加果糖的效果优于蔗糖，而提高蔗糖浓度可以促进茎叶生长；不同品种茎尖的蔗糖酶活性存在较大差异，生长良好的品种（剑持）其蔗糖酶活性及酶蛋白含量高于生长较差的湖桑３２号和一之濑；茎尖内源激素含量及其比例差异明显．其中ＧＡ、ＡＢＡ含量及其比值剑持较高，其次为一之濑，湖桑３２号最低     

赤霉酸及矮壮素对苦瓜性别表现的影响

以兰山大白、株洲长白和英引３个苦瓜品种为材料进行外源激素处理对苦瓜植株性别表现影响的试验．结果表明，苗期进行ＧＡ３２５～１００ｍｇ／Ｌ处理有明显的促雌效果；ＣＣＣ５０～２００ｍｇ／Ｌ处理则有促雄效果，但促雄程度因品种而异，ＣＣＣ５００ｍｇ／Ｌ处理对兰山大白有适度的促雌作用．外源激素处理对苦瓜植株性别分化的影响可持续８０ｄ以上．苦瓜第一雌花形成与茎尖ＧＡ３含量达到峰值有关，２５ｍｇ／Ｌ的ＧＡ３处理使茎尖ＧＡ３含量的峰值提前出现而使第一雌花形成提早，而１００ｍｇ／ＬＣＣＣ处理使茎尖ＧＡ３含量先下降再逐渐回升而使植株第一雌花形成滞后