Accumulation of malathion residues in grain stored on malathion-treated wood surfaces

Laboratory studies were conducted to determine whether insecticides applied to storage structures are able to move past a single layer of grain kernels to give adequate control of stored-grain insects. The extent of uptake of insecticides was assessed on three layers of wheat in contact with wood surfaces treated with malathion 836 g litre^?1 e.c. at 1–0 g a.i. m^?2 using chemical and biological methods at predetermined time intervals. There was a progressive uptake of malathion beyond the layer directly in contact with the treated surfaces and the uptake depended on the duration of storage. After 8 weeks a sufficient amount of malathion accumulated on the top layer of grain kernels to cause 100% mortality of adult Tribolium castaneum (Herbst).     

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.     

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.     

Thoracoscopic Lung Lobectomy for Primary Lung Tumors in 13 Dogs

Objectives

To report our experience with thoracoscopic lung lobectomy in dogs with primary lung tumors and compare the long‐term outcome between dogs with primary lung tumors treated with lobectomy via thoracoscopy or thoracotomy.

Study Design

Retrospective case series; case–control study.

Animals

Thirteen dogs with primary lung tumors treated with thoracoscopic lung lobectomy; case‐matched cohort of 9 dogs with primary lung tumors treated with lobectomy via thoracotomy.

Methods

Medical records from dogs that underwent thoracoscopic lung lobectomy at a single institution were reviewed. Only cases with primary lung tumors were included. Surgical complications and conversion rate were reported. Cases without conversion and with clean margins on histologic examination were matched on prognostic criteria to cases with primary lung tumors treated with lobectomy via thoracotomy. Survival was compared between thoracoscopy and thoracotomy.

Results

Thirteen dogs with primary lung tumors that measured 2.2–7 cm underwent thoracoscopic lung lobectomy. Nine dogs were diagnosed with carcinoma and 4 with histiocytic sarcoma. There were 3 conversions to open thoracotomy because of poor visualization. There were no differences in short‐term outcome between dogs that had their procedures completed via thoracoscopy and those that were converted to thoracotomy. Nine dogs with clean margins were matched with 9 dogs treated via thoracotomy. Mean (standard deviation) followup was 367 (327) days for dogs undergoing thoracoscopy and 603 (612) days for dogs undergoing thoracotomy. The 2‐year survival rate was 44% for thoracoscopy and 56% for thoracotomy (P = .942).

Conclusion

Selected primary lung tumors in dogs can be safely resected with thoracoscopy and not affect long‐term outcome.

     

Extirpation, colonization, and habitat dynamics of a keystone species along an urban gradient

Using 5 years of patch occupancy data for 384 habitat fragments, we evaluated population and habitat dynamics of the black-tailed prairie dog in urban habitat remnants in the rapidly developing landscape of Denver, CO, USA. Specifically, we evaluated the landscape factors, including fragment area, age, and connectivity, that characterize the habitat fragments most likely to be colonized by prairie dogs, as well as those experiencing local extinctions. In addition, we determined which patch types were most often removed by land development. Sites in proximity to colonies were more likely to be colonized by prairie dogs. Local extinctions were most common on isolated colonies, and older and more isolated colonies were more likely to be extirpated by human activity. In general, smaller and older habitat patches were at the highest risk of being lost to land development. Our results provide observations of dynamic changes to the distribution of a potential keystone species in an urban area, which can be used to inform island biogeographic and metapopulation models for wildlife persistence in developing landscapes. Although populations are currently in decline, most local extinctions are the direct result of human activity, and we suggest that prairie dogs in this area can persist with appropriate management.