Anesthetic protocol: propofol use in Rhesus macaques (Macaca mulatta) during magnetic resonance imaging with stereotactic head frame application.

Magnetic resonance image (MRI) guidance is often necessary for accurate targeting for stereotactic intracranial surgery in animals used for experimental research studies. The magnetic field created by the MR imaging equipment, logistics of the use of stereotactic head frame in confined space and the need to limit movement of the subject during the imaging creates unique challenges. We demonstrate in this study the usefulness of intravenous propofol to anesthetize adult Rhesus monkeys to obtain high resolution 3D MR images immediately followed by conversion to inhalation anesthesia and stereotactic intracranial surgery with the head frame 'in situ.' There was minimal morbidity with achieving a high degree of precision for the stereotactic targeting.

Fenbendazole treatment without environmental decontamination eradicates Syphacia muris from all rats in a large, complex research institution.

Syphacia muris parasitism was eliminated from rats and voles by feeding fenbendazole-medicated chow (150 ppm) for five 7-day periods; treatment periods were separated by 7-day periods of feeding non-medicated chow, yielding atotal treatment course of 9 weeks. No other manipulations to facilitate eradication, including the use of filter tops, autoclaved cages, environmental decontamination, colony depopulation, breeding cessation, and research restriction, were done. The examination of 3143 cellophane-tape impressions of the anus and 160 cecal examinations from euthanized rats and voles during the treatment period and for 7 months afterwards confirmed the efficacy of treatment. Treatment was rapidly effective in voles. In rats, pinworm eggs persisted at high levels for 2 weeks after the start of treatment, but no eggs were found after 22 days.

Changes in rat paw perfusion after experimental mononeuropathy: assessment by laser Doppler fluxmetry.

UNLABELLED: This study was performed to determine the changes in perfusion that occur after chronic constriction injury (CCI). Male Sprague-Dawley rats weighing 275-300 g had loosely constricting ligatures placed around the left sciatic nerve. Paw withdrawal latency (PWL) to heat, skin temperature, and skin perfusion (laser Doppler) of the hind paws were measured before and for 30 days after CCI. PWL decreased significantly on the side of the CCI (maximum of 34% decrease on Postoperative Day [POD] 3), then returned to normal over a 20-day period. Skin temperature initially increased on the side of CCI, then decreased with respect to the control limb on PODs 20-30. Despite the initial increase in skin temperature on the side of CCI, skin perfusion significantly decreased immediately after CCI (maximum of 51% decrease on POD 6). The perfusion gradually returned to normal over 20 days. Because return to normal perfusion occurred while the skin temperature became colder than the control side, we conclude that there is no relationship between paw surface temperature and perfusion. IMPLICATIONS: Our data suggest that loss of sympathetic tone in thermoregulatory arteriovenous anastomoses leads to decreased nutritional blood flow to the skin of the affected limb after chronic constriction injury, which is consistent with the findings reported in humans with reflex sympathetic dystrophy.

Ivermectin eradication of pinworms from rats kept in ventilated cages.

Studies using rats that were naturally infested with Syphacia muris and kept in forced-air, individually ventilated cages showed that ivermectin given orally at a dose of 2 mg/kg for three treatments at 7- or 9-day intervals was eradicative. Paired ivermectin treatments given at 7- or 9-day intervals were ineffective in eliminating parasitism. Pinworm eggs persisted on the perianal region of rats for up to 17 days and eggs were also present in soiled contact bedding within cages and on surfaces within the animal room. Anal tapes as a diagnostic test had 88% sensitivity in detecting pinworms.

The effectiveness of a microisolator cage system and sentinel mice for controlling and detecting MHV and Sendai virus infections.

Experiments were conducted to determine (a) whether BALB/c mice housed on soiled bedding can be used as sentinels for the detection of Sendai virus and MHV from infected mice housed in microisolators, and (b) whether the microisolator caging system protects mice against Sendai virus and MHV infections. Sentinel mice were housed in microisolator cages, exposed continuously to soiled bedding and bled at 21 and 42 days for serology. All sentinel mice were seropositive for MHV by 42 days; however, sentinel mice exposed to soiled bedding were seronegative for Sendai virus at 21 and 42 days. These results suggest that sentinels housed on soiled bedding may not detect all infectious murine viruses. This study also showed that the microisolator caging system provided an effective barrier against MHV infection at the cage level and suggests that the microisolators should protect mice against other infectious agents.

Outbreaks of Pneumocystis carinii pneumonia in colonies of immunodeficient mice.

Outbreaks of Pneumocystis carinii pneumonia occurred in colonies of nu/nu and scid/scid mice at four different institutions. The disease, which was characterized by chronic wasting and respiratory insufficiency, was more severe in older mice and in animals housed in cages with special protective tops. Histopathologic features included alveolar filling with the typical foamy honeycomb material and a mild, nonspecific host inflammatory response. Immunofluorescence and immunoblotting studies suggested the P. carinii isolate was of mouse rather than of rat or human origin, and the outbreaks could be related to each other by common vendor or source of breeding animals. Once P. carinii became established in a mouse colony, the organism tended to persist for long periods of time. The principal control measure was depopulation of the colony, although limited experience with the administration of trimethoprim-sulfamethoxazole was encouraging. Thus, outbreaks of pneumocystosis are a serious problem among colonies of immunodeficient mice, with important implications for the use of these animals in biomedical research. Data obtained by studying these outbreaks should enhance understanding of the pathogenesis of P. carinii pneumonia and be helpful in formulating improved methods of detection and control.

Vitamin E deficiency in goldfish fed a shellfish derived diet.

Six month old, laboratory-raised goldfish (Carassius auratus) used in morphologic studies of retinal development developed progressive fraying and deterioration of the tail and fins that reached epizootic proportions and culminated in fungal infection and death. Diagnostic histopathology showed marked skeletal muscle degeneration in the muscles of the tail and caudal body wall compatible with a vitamin E/selenium deficiency. Ration analysis demonstrated inadequate vitamin E in the commercial shrimp-based diets fed to the goldfish fry. Replacement of shrimp-derived diets by a commercial trout diet containing adequate levels of vitamin E was curative.