Isolation,characterization, and properties of factor F1 from mitochondrial preparations of housefly (Musca domestica L.) thorax

A water-soluble Mg²⁺-dependent ATPase (coupling factor F₁) was isolated from the mitochondria of housefly thorax. It comprised about 14% of the proteins from a crude preparation. The F₁ preparation was nearly homogeneous as assessed by gel electrophoresis, isoelectric focusing, and electron microscopy. It was composed of five subunits with the following apparent molecular weights: α, 68,000; β, 61,000; γ, 38,000; δ, 27,000; and ?, 17,500. The isoelectric pH (pI) of this protein was 7.3. F₁ had a pH optimum of 8.2 and a temperature optimum between 37 and 45°C. The enzyme was fairly stable at 25°C. Nearly complete loss of activity was noticed at 0°C, while at 0 or 25°C, glycerol (20%) partially stabilized the enzyme activity against such inactivation. The K_m value of the enzyme with respect to ATP was 0.4 mM. The activity was stimulated by low concentrations of 2,4-dinitrophenol. The enzyme was inhibited by azide, p-hydroxymercuribenzoate, and guanidine hydrochloride. Oligomycin and the pesticides pyrethrin, cyhexatin, and DDT have no effect on the enzyme activity. However, all of these chemicals inhibited intact Mg²⁺- ATPase. The results are discussed in the light of differential responses of soluble and intact ATPase to these pesticides.     

Methods and characteristics used in resident selection within the American College of Veterinary Ophthalmologists

A survey of Diplomates from the American College of Veterinary Ophthalmologists, which trains residents, confirms that subjective criteria are most commonly used in selecting new residents. The ophthalmologist(s) who oversee(s) the training was/were primarily responsible for resident selection. In general, Diplomates seemed to be searching for a resident who was intelligent, could communicate well, was hard working, and had good interpersonal skills. The most important part of an application was the letters of recommendation, with the most important consideration being how well the person doing the selecting knew the author of a letter. The current process of resident selection does result in a majority of residents' completing their programs and ultimately becoming Diplomates of the American College of Veterinary Ophthalmologists.     

Hypofractionated radiation therapy for the treatment of malignant melanoma and squamous cell carcinoma in dogs and cats

This study describes the experience with hypofractionated radiation therapy of squamous cell carcinoma and melanoma in dogs and cats. A total dose of 32-48 Gray (Gy) was delivered once a week in 8 Gy fractions. 34 animals in which a complete surgical excision was impossible were treated. There was no tumor detectable macroscopically in 14 patients at the beginning of radiation therapy. In 20 animals the median volume of the tumor was 9.9 cm3. The median survival times and the local tumor control of squamous cell carcinoma of the oral and nasal cavities and of the body are comparable to results which were reached with a Monday-Wednesday-Friday scheme. For the treatment of Melanoma the hypofractionated radiation therapy is first choice. There are no significant side effects. Late side effects did not occur. 88% of the owners are satisfied with this kind of treatment and would choose it again.     

Comparison of models for estimation of genetic parameters for mature weight of Hereford cattle

Genetic parameters of mature weight are needed for effective selection and genetic evaluation. Data for estimating these parameters were collected from 1963 to 1985 and consisted of 32,018 mature weight records of 4,175 Hereford cows that were in one control and three selection lines that had been selected for weaning weight, for yearling weight, or for an index combining yearling weight and muscle score for 22 yr. Several models and subsets of the data were considered. The mature weight records consisted of a maximum of three seasonal weights taken each year, at brand clipping (February and March), before breeding (May and June), and at palpation (August and September). Heritability estimates were high (0.49 to 0.86) for all models considered, which suggests that selection to change mature weight could be effective. The model that best fit the data included maternal genetic and maternal permanent environmental effects in addition to direct genetic and direct permanent environmental effects. Estimates of direct heritability with this model ranged from 0.53 to 0.79, estimates of maternal heritability ranged from 0.09 to 0.21, and estimates of the genetic correlation between direct and maternal effects ranged from -0.16 to -0.67 for subsets of the data based on time of year that mature weight was measured. For the same subsets, estimates of the proportions of variance due to direct permanent environment and maternal permanent environment ranged from 0.00 to 0.09 and 0.00 to 0.06, respectively. Using a similar model that combined all records and included an added fixed effect of season of measurement of mature weight, direct heritability, maternal heritability, genetic correlation between direct and maternal effects, proportion of variance due to direct permanent environmental effects, and proportion of variance due to maternal permanent environmental effects were estimated to be 0.69, 0.13, -0.65, 0.00, and 0.04, respectively. Mature weight is a highly heritable trait that could be included in selection programs and maternal effects should not be ignored when analyzing mature weight data.     

Canine choroidal melanoma with metastases

A 3-year-old-female, spayed Golden Retriever was examined for a unilateral retinal detachment with exophthalmos. Ultrasonographically, a mass was detected with intra- and extraocular extension. The orbit was exenterated and the dog recovered uneventfully. Histopathologic diagnosis was a primary choroidal melanoma with orbital extension, however, the behavioral and cytologic features were benign. Routine examinations postsurgically were nonremarkable. Twenty-one months after surgery the dog was euthanized for respiratory collapse with radiographic signs of metastasis. Necropsy revealed black lesions in the lung and liver. Histopathologic diagnosis was metastatic melanoma with morphology and behavior identical to the primary choroidal melanoma. This is the first definitive case of a canine choroidal melanoma with metastasis.