Electrocardiographic values from clinically normal, anesthetized ferrets (Mustela putorius furo).

Electrocardiograms were recorded from 25 clinically normal male ferrets anesthetized with ketamine and xylazine and from 7 ferrets anesthetized with ketamine alone. Ferrets anesthetized with ketamine alone had excessive salivation, open eyes, muscle tremors, muscle twitching, paddling motions, attempts to stand, and an unstable ECG baseline. Because ketamine/xylazine combination resulted in induction and good muscle relaxation, the ECG had little interference resulting from muscular movement.

Prevention of graft-versus-host disease by treatment of bone marrow with gliotoxin in fully allogeneic chimeras and their cytotoxic T cell repertoire.

Gliotoxin, a secondary fungal metabolite, at nanomolar concentrations, irreversibly inhibits murine T cell proliferation to mitogen. Treatment of allogeneic spleen cells with gliotoxin allows their transfer into sublethally irradiated recipients without inducing a GVH reaction. Gliotoxin treatment of bone marrow allows the establishment of fully allogenic bone marrow chimeras free of GVH disease. The cytotoxic T cell repertoire against influenza virus in these animals is restricted to both host- and donor-type MHC. However, their immune competence is severely compromised by their lack of host MHC-type stimulator cells.

Enhancement of murine thyroid allograft survival after 16 to 20 hours' organ culture.

Fully allogeneic thyroid organs cultured 16-20 hr in Hanks' balanced salt solution (HBSS) were transplanted to mice under the kidney capsule. Organ cultures maintained in 5% CO2 and air or in 100% nitrogen atmosphere in HBSS survived beyond the normal period required for graft rejection, in contrast to those maintained in room air or thyroids cultured in Eagle's minimum essential medium. Rejection of HBSS-cultured allogeneic thyroids can be induced by the injection of donor peritoneal exudate cells into the recipient 2 days after transplant. Lymphoid stimulator cells cultured overnight in HBSS, but not in (Eagle's) minimum essential medium in 5% CO2 and air, failed to induce alloreactive cytotoxic T cells in mixed lymphocyte cultures in vitro. The data suggest that short-term organ culture in a chemically simpler and nutritionally deficient medium in a low-oxygen environment enhances allograft survival. This is in contrast to the presently held theory, in which high-oxygen concentration is believed responsible for enhancement of allograft survival. This procedure should prove helpful in further determination of the factors involved in homograft rejection.

Dirofilariasis in a ferret.

An adult male ferret was found to be lethargic and dyspneic. Necropsy revealed 21 worms in the heart, vena cava, and pulmonary artery. The worms were identified as Dirofilaria immitis. Histologic examination of lung tissue revealed numerous microfilariae.

Serum concentrations of gentamicin in cats.

Twenty-one adult cats, allotted into 2 groups, were given gentamicin sulfate at dosages of either 5.0 mg/kg of body weight or 2.5 mg/kg as a single IM injection. During a 24-hour period, serum concentrations of gentamicin were measured serially, using a fluorescence immunoassay. The mean peak serum concentration of gentamicin in cats given 5.0 mg/kg was 23.1 micrograms/ml at postinjection hour (PIH) 0.5; thereafter, the mean serum concentration steadily decreased to 2.0 micrograms/ml at PIH 24. The mean peak serum concentration for cats administered 2.5 mg/kg was 9.1 micrograms/ml at PIH 0.5; thereafter, the mean serum concentration steadily decreased to 1.3 micrograms/ml at PIH 12. Serum therapeutic concentrations, without exceeding toxic concentrations, were attained at the 2.5 mg/kg dosage.

Evaluation of ketamine, ketamine-xylazine and ketamine-diazepam anesthesia in the ferret.

Ketamine, ketamine-xylazine, and ketamine-diazepam were evaluated clinically in 15 ferrets, and safe dosage was determined for each. All of the three regimens provided excellent immobilization. However, muscle rigidity and incomplete analgesia were noted in ketamine alone and in ketamine-diazepam respectively. It was concluded that 25 mg/kg ketamine and 2 mg/kg xylazine intramuscularly provided acceptable analgesia, muscle relaxation, duration and smooth recovery, although cardiac arrhythmias were a concern and require careful observation.

Effects of influenza, mumps, and western equine encephalitis viruses on fetal rhesus monkeys (Macaca mulatta).

Pregnant Rhesus monkeys were infected via instillation of influenza, mumps and western equine encephalomyelitis viruses respectively into the amniotic sacs at approximately 90 days gestation to determine if fetal infections would occur. Virus was recovered from fetal tissues after seven days in 100% of the exposed animals. Thus, the viruses are capable of causing fetal infection. Rhesus monkey fetuses were inoculated with influenza, mumps and WEE viruses by the direct intracerebral route at approximately 90 days gestation to determine possible teratogenicity of the viruses. influenza virus caused no malformations or measurable fetal effects. Mumps virus resulted in significant fetal mortality. WEE virus resulted in a 100% incidence of encephalitis and hydrocephalus. Thus, mumps and WEE viruses are teratogens in primates and are potential teratogens of man.

Fetal mortality and malformations associated with experimental infections of western equine encephalomyelitis vaccine virus in rhesus monkeys (Macaca mulatta).

Pregnant Rhesus monkeys were infected via installation of Western Equine Encephalomyelitis (WEE) vaccine virus into the amniotic sacs at 50 and 80 days gestation to determine if the resulting infections would produce fetal mortality or fetal malformations, particularly within the central nervous system. Of those receiving virus at 50 days gestation, 13 of 18 fetuses were aborted or dead in utero at time of Caesarean section; 2 of 18 were malformed (hydrocephalus and polyarthrosis); and 3 of 18 were anatomically normal. Of those receiving virus at 80 days gestation four of eight fetuses were aborted or dead in utero at time of Caesarean section, one of eight was malformed (hydrocephalus) and three of eight were anatomically normal. Three of three controls receiving neutralized virus at each gestational age were anatomically normal. Fetal WEE vaccine virus infection significantly increased fetal mortality and resulted in a significant incidence of fetal malformations.

Urolithiasis in ferrets (Mustela putorius).

Urinary calculi was observed frequently in ferrets which were from a group used for influenza research. They were submitted for necropsy with various clinical signs. The calculi were composed of magnesium ammonium phosphate hexahydrate and were found in the pelvis of the kidney, urinary bladder and urethra. Crystals of undetermined nature occasionally were observed in the kidneys.

Reduced beta adrenergic responsiveness in rats treated with estrogenic agents.

Chronic treatment with ethynyl estradiol alone (48-50 mug/kg/day) and in combination with several doses of norethynodrel either attenuated or prevented the increase in tail skin temperature accompanying sC. administration of isoproterenol (200 mug/kg b.wt.) to male and female rats. Dietary administration of an oral contraceptive containing norethynodrel and mestranol (7.5 mg/kg of food) was also accompanied by an attenuated response to isoproterenol. Attenuation of the tail skin temperature response was present in all groups after 3 to 5 weeks of treatment but was detectable in the oral contraceptive-treated group after 1 week of treatment. All steroids and combinations, except norethynodrel administered alone (154 mug/kg/day), reduced body weight gain.

PIP: 2 experiments designed to test beta adrenergic responsiveness of the tail skin temperature of rats treated with an estrogenic agent, a progestational agent, and both combined are reported. In the 1st experiment, 24 male rats were divided into 4 groups: 1) controls, 2) a 10 mm silastic tube containing norethynodrel (crystalline) was implanted, 3) a silastic tube containing crystalline ethinyl estradiol was implanted, and 4) both drugs were implanted. At 15 weeks the tail temperature of the rats and their colon temperature were observed for 1 hour. A 200 mcg injection of 1-isoproterenol/kg was given and the rats observed for an additional 2 hours. 22 weeks after implantation the rats were sacrificed and silastic tubes weighed in order to calculate the daily drug dose. In the 2nd experiment 30 female rats were divided into 5 groups: 1) controls, 2) a 20 mm length of silastic tube containing crystalline norethynodrel implanted beneath the shoulder blades and a 10 mm length of tubing containing crystalline ethinyl estradiol implanted beneath the skin covering the skull, 3) a 10 mm length of tubing containing norethynodrel plus a 20 mm length containing ethinyl estradiol, 4) a 10 mm length of tubing containing norethynodrel and a 10 mm length containing ethinyl estradiol, and 5) the oral contraceptive Enovid with 5.0 mg norethynodrel and .075 mg mestranol mixed in with food. Temperature observations were made at the end of week 1 after implantation, Week 3, and Week 5. Room temperature was maintained at 23 degrees C. During Week 12 the tail temperatures were again observed but in a room kept at 30 degrees C for 60 minutes. 100 mcg phenylephrine was administered at the end of this time to determine whether responsiveness of tail skin temperature to an alpha adrenergic agonist differed among the groups. Food intake was measured during Week 18. The rats were then sacrificed and daily rate of drug intake computed. Chronic treatment with ethinyl estradiol alone (48-50 mcg/kg/day) and in combination with several doses of norethynodrel either attenuated or prevented the increase in tail skin temperature accompanying sc administration of isoproterenol to male and female rats. Dietary administration of Enovid (7.5 mg/kg of food) was also accompanied by an attenuated response to isoproterenol. This reponse was detectable in all groups after 3-5 weeks treatment but was detectable after 1 week of the start of oral contraceptive treatment. All steroids and combinations, except norethynodrel administered alone (154 mcg/kg/day), reduced body weight gain.