Anesthesia for geriatric patients.

Choosing the best anesthetic agents for each geriatric animal does not in itself ensure a successful outcome. Aggressive, careful, vigilant monitoring during the anesthetic and recovery periods is required to detect and correct alterations in homeostasis that may develop during the perianesthetic period. With appropriate preoperative screening, informed choice and judicious dosing of anesthetics, and careful monitoring and supportive care, the risk of anesthesia in geriatric animals can be greatly reduced.     

Chronic obstipation in a leopard (Panthera pardus) caused by intrapelvic uterine leiomyoma compression of the distal colon.

A 6-yr-old female leopard (Panthera pardus) was evaluated for a history of chronic obstipation of 4-mo duration. Radiographic, ultrasonographic, and computed tomographic evaluation revealed an intrapelvic mass that was compressing the distal colon. Because of the difficulties of postsurgical management of this animal, the owner requested euthanasia. On postmortem examination, a mass measuring 3 times 5 times 10 cm was found arising from the body of the uterus. Histopathologic evaluation of the mass revealed a leiomyoma of the uterus. This case report documents the presence of a uterine tumor in a large felid that resulted in constipation and obstipation. Additionally, the value and limitations of the imaging modalities used to provide diagnostic, prognostic, and treatment options are discussed.     

Efficacy of selected coccidiostats in sandhill cranes (Grus canadensis) following challenge.

The anticoccidial efficacy of amprolium, clazuril, and monensin were studied in sandhill cranes (Grus canadensis) infected with a mixture of Eimeria spp. oocysts. Five groups of four 1-day-old sandhill crane chicks were maintained on a crumbled ration containing no coccidiostat, amprolium at 2.2 ppm, clazuril at 1.1 ppm, clazuril at 5.5 ppm, or monensin at 99 ppm. After 2 wk on their respective feeding regimens, birds in each of the five groups were administered 25 x 10(3) pooled sporulated Eimeria spp. oocysts per os and observed for another 3 wk. A sixth group of four chicks served as nonmedicated, nonchallenged control during the study. Clinical signs and lesions consistent with disseminated visceral coccidiosis were observed in all challenged controls and birds fed amprolium and clazuril. Birds in these groups died 9-10 days after challenge. In contrast, only one monensin-medicated bird had clinical signs of disseminated visceral coccidiosis, and it died 13 days after challenge (DAC). This and an asymptomatic bird that were necropsied at study termination had less-severe gross and microscopic lesions of disseminated visceral coccidiosis. Two of three monensin-treated birds that survived challenge passed from 50 to 500 coccidial oocysts 11 to 18 DAC but were negative at study termination. Of the coccidiostats tested, monensin, at the dietary level of 99 ppm, was the only anticoccidial drug that provided protection against experimentally induced disseminated visceral coccidiosis in sandhill cranes.     

Low internal conductivity of Aplysia neuron somata

The internal conductivity of Aplysia neuron somata was measured by passing constant current pulses across a calibrated four-electrode array. The intracellular medium is less than one-tenth as conductive as seawater. The low conductivity probably results from structured cell water since ions are present in quantity and do not appear to be bound.     

Immobilized long-lived free radicals at the host–pathogen interface in sycamore (Acer pseudoplatanusL.)

High concentrations (up to 2.4 m ) of long-lived, immobilized, organic free radicals were observed in column boundary layer (CBL) reaction zones at the boundary between fungal lesions and healthy, functional sapwood (xylem) in sycamore (Acer pseudoplatanusL.). These free radicals, with measured half-lives of up to 142 days at ambient temperature, were associated with the green polymeric material characteristically deposited in CBL reaction zones in this species, and may represent a novel category of chemical defence in plants. Such free radicals could contribute to the durable protection required in the bulky secondary tissues of living trees by acting as free radical scavengers, quenching the free radical chain reactions involved in the biodegradation of lignocellulose, thus protecting cell walls from decay and conferring a barrier function on the altered tissue. Reaction zone tissues were more resistant to decay and fungal colonization than normalA. pseudoplatanussapwood.     

Simulation model for evaluation of testing strategies for detection of paratuberculosis in midwestern US dairy herds

We developed a stochastic simulation model to compare the herd sensitivity (HSe) of five testing strategies for detection of Mycobacterium avium subsp. paratuberculosis (Map) in Midwestern US dairies. Testing strategies were ELISA serologic testing by two commercial assays (EA and EB), ELISA testing with follow-up of positive samples with individual fecal culture (EAIFC and EBIFC), individual fecal culture (IFC), pooled fecal culture (PFC), and culture of fecal slurry samples from the environment (ENV). We assumed that these dairies had no prior paratuberculosis-related testing and culling. We used cost-effectiveness (CE) analysis to compare the cost to HSe of testing strategies for different within-herd prevalences. HSe was strongly associated with within-herd prevalence, number of Map organisms shed in feces by infected cows, and number of samples tested. Among evaluated testing methods with 100% herd specificity (HSp), ENV was the most cost-effective method for herds with a low (5%), moderate (16%) or high (35%) Map prevalence. The PFC, IFC, EAIFC and EBIFC were increasingly more costly detection methods. Culture of six environmental samples per herd yielded >or=99% HSe in herds with >or=16% within-herd prevalence, but was not sufficient to achieve 95% HSe in low-prevalence herds (5%). Testing all cows using EAIFC or EBIFC, as is commonly done in paratuberculosis-screening programs, was less likely to achieve a HSe of 95% in low than in high prevalence herds. ELISA alone was a sensitive and low-cost testing method; however, without confirmatory fecal culture, testing 30 cows in non-infected herds yielded HSp of 21% and 91% for EA and EB, respectively.     

Effects of Exogenous Insulin on Luteolysis and Reproductive Cyclicity in the Mare

Insulin is a pancreatic hormone that classically regulates carbohydrate and fat metabolism, but also appears to play a role in various reproductive processes. A preliminary study suggested insulin production by day 10 to 18 equine conceptuses. The aim of the present study was to examine the hypothesis that insulin is the conceptus signal responsible for maternal recognition of pregnancy (MRP) in the mare, or otherwise influences reproductive cyclicity during the MRP period. Six Warmblood mares were treated daily during days 7 to 17 after ovulation of two successive oestrous cycles with either (short and intermediate acting) insulin or control saline. Mares were assigned randomly to treatment, and crossed over during the subsequent cycle. Time of ovulation and corpus luteum surface area were determined by serial transrectal ultrasonographic examination of the mares' ovaries, and daily jugular vein blood samples were analysed for progesterone and luteinizing hormone (LH) concentrations. On day 14 of dioestrus, the luteolytic drive was examined by measuring systemic 15-ketodihydroprostaglandin F_{2 α} (PG-metabolite) release in response to oxytocin challenge. In addition, yolk sac fluid recovered from 32 day 10 to 14 equine conceptuses was analysed for insulin concentrations. Insulin administration did not affect luteal size, dioestrus length, the interovulatory interval, or circulating LH concentrations. Insulin administration also failed to suppress oxytocin-induced PGF_{2 α} release, and tended to depress systemic progesterone concentrations. Finally, insulin could not be detected in the yolk sac fluid of day 10 to 14 equine conceptuses by radio-immunoassay. It is concluded that insulin administered daily during days 7 to 17 of dioestrus has little or no effect on reproductive cyclicity in the mare, and is unlikely to be the MRP signal.     

Translocation as a species conservation tool: status and strategy

Surveys of recent (1973 to 1986) intentional releases of native birds and mammals to the wild in Australia, Canada, Hawaii, New Zealand, and the United States were conducted to document current activities, identify factors associated with success, and suggest guidelines for enhancing future work. Nearly 700 translocations were conducted each year. Native game species constituted 90 percent of translocations and were more successful (86 percent) than were translocations of threatened, endangered, or sensitive species (46 percent). Knowledge of habitat quality, location of release area within the species range, number of animals released, program length, and reproductive traits allowed correct classification of 81 percent of observed translocations as successful or not.     

Identification of bovine T cell stimulatory antigens using a cosmid library of Mycobacterium bovis in Mycobacterium smegmatis

Culture filtrates derived from a Mycobacterium bovis cosmid library in Mycobacterium smegmatis were screened for T cell antigens. Recognition and reactivity were measured by the levels of lymphocyte proliferation and the levels of gamma interferon (IFN-gamma) produced when the culture filtrates were incubated with peripheral blood mononuclear cells (PBMC) taken from cattle immunised with M. bovis BCG. The screening system was optimised to distinguish between M. bovis secreted antigens and normal M. smegmatis secreted proteins. From ten culture filtrates screened, two were identified that induced lymphocyte proliferation and IFN-gamma production. Analysis of the DNA inserts from the recombinant cosmids suggest that they may code for different proteins. The results demonstrate that screening recombinant M. smegmatis culture filtrates can be used to identify M. bovis T cell antigens that are recognised by immunised cattle. These antigens may be important for the development of vaccines with protective ability against bovine tuberculosis.