Osteocyte apoptosis and osteoclast presence in chicken radii 0-4 days following osteotomy.

Osteocyte apoptosis caused by load-induced microdamage is followed by osteoclastic bone remodeling, and a causal link between apoptosis and repair has been suggested. The objectives of the present study were to use a chick model to examine the incidence of osteocyte apoptosis and the presence of osteoclasts during the first 96 hours following an osteotomy, prior to extensive callus mineralization. Osteotomies were performed on the right radii of 24 chicks at 23-24 days of age. The left radii served as controls. Radii were collected and processed at six time points following surgery (0, 12, 24, 48, 72, and 96 hours). Decalcified bone tissue sections were stained either for apoptosis using a modified TUNEL procedure or for tartrate-resistant acid phosphatase to identify osteoclasts in the intracortical and periosteal envelopes. The percentage of apoptotic osteocytes, as well as osteoclast counts (n/mm or n/mm2) were quantified in four regions (0-1, 1-2, 2-4, and 4-8 mm from the site of the osteotomy; regions 1-4, respectively) in the osteotomized radii and in the same measured areas in the control radii. Data for osteocyte apoptosis and osteoclasts in the control limb were subtracted from the osteotomized limb data to identify differences due to surgical influence. The incidence of osteocyte apoptosis was significantly higher at 12, 24, 48, and 72 hours versus 0 hours following osteotomy, and the response was highest in region 1; however, there was no interaction between time and region. Intracortical osteoclast counts (n/mm2) were elevated after 48 hours, and the response was similar in all regions. The data demonstrate that osteocyte apoptosis occurs within 24 hours in response to an osteotomy and temporally precedes an increase in osteoclast presence. Hence, osteocyte apoptosis may play a role in signaling during the bone healing process.

Refractive state and accommodation in the eyes of free-swimming versus restrained juvenile lemon sharks (Negaprion brevirostris).

Optical measurements of the refractive state of the eyes of various shark species typically have depicted sharks as hyperopic (far-sighted) with little evidence of accommodation (i.e. the ability to change focus for visualizing objects at different distances from the eye). In this study, we used infrared video retinoscopy to measure the refractive state in juvenile lemon sharks (Negaprion brevirostris). This technique allows dynamic measurement of refractive state in free-swimming animals as they pass by an aquarium window. We found that unrestrained lemon sharks are focused emmetropically relative to a 1-m distant photorefractor for the lateral visual field. However, when restrained either right side up or upside down (the latter inducing tonic immobility), the sharks become increasingly hyperopic, an artifact also reported in some other vertebrates. In addition, unrestrained lemon sharks display small amplitude accommodative excursions. Thus, refractive state measurements on restrained sharks in general may not reflect the natural, resting state of the shark eye, but rather, an induced hyperopia and lack of accommodative function. Such an artifact may be present in other vertebrate species, underscoring the need to obtain measurements of refractive state in unrestrained animals.

Granulosa cell tumor in a guinea pig.

Abdominal distention is a common clinical sign in guinea pigs and may have many causes. Abdominal ultrasonography may be a useful diagnostic tool in differentiation of abdominal disorders in guinea pigs. Ovariohysterectomy is indicated for granulosa cell tumors and cystic rete ovarii in guinea pigs.

Avian analgesia.

Understanding behavioral indicators of pain and other assessment techniques can help one to recognize pain in birds and prompt us to treat birds with analgesics. An analgesic plan needs to include several modalities to help reduce pain in the avian patient. Analgesic therapy should be directed at treating the disease/injury in the periphery, and the changes that occur in the central nervous system (CNS). Both opioid and nonsteroidal anti-inflammatory drug (NSAID) therapeutics can be selected to provide analgesia for the avian patient.

Effects of hemolysis on plasma electrolyte and chemistry values in the common green iguana (Iguana iguana).

Hemolysis of serum and plasma samples is a common problem in veterinary diagnostic laboratories. We measured the effects of hemolysis on nine plasma analytes in 10 clinically normal common green iguanas (Iguana iguana). Blood samples with moderate and marked hemolysis were produced from each iguana by freezing, centrifuging, and decanting plasma from a portion of each blood sample, and combining the nonhemolyzed plasma with different amounts of hemolyzed plasma from the same individual. Moderate hemolysis significantly increased plasma phosphorus levels. Marked hemolysis significantly increased plasma values of potassium, phosphorus, total protein, and aspartate aminotransferase. The severity of hemolysis must be considered when interpreting values for these analytes in iguana plasma.

Ultrasonography and fine needle aspirate cytology of the mesenteric lymph node in normal domestic ferrets (Mustela putorius furo).

The large mesenteric lymph node of 28 normal ferrets was imaged with ultrasound. The large node, located in the mid-abdomen at the root of the mesentery, was round to ovoid and uniformly hyperechoic. Mean ultrasonographic dimensions of the lymph node were 12.6 +/- 2.6 mm by 7.6 +/- 2.0 mm. Fine needle aspirates of 20 lymph nodes were obtained either using ultrasound guided free-hand techniques or at necropsy. The cytological descriptions were compared to histological descriptions of 13 lymph node core biopsies obtained during laparotomy or necropsy as well as 10 peripheral blood smear differentials. The large mesenteric lymph node of ferrets could be easily imaged and measured by ultrasound and evaluated by fine needle aspirate cytology. Normal lymph node cytology may include an eosinophilic infiltrate.

Clinical pathology of the domestic rabbit. Acquisition and interpretation of samples.

Diagnostic laboratories are receiving increasing numbers of samples from practitioners as they strive to diagnose complex disease processes and manage rabbit cases. Proper acquisition of diagnostic samples and interpretation of results are key skills necessary for successful management of medical cases. This article reviews the collection and interpretation of clinicopathologic samples commonly used in rabbits.

A technique for evaluating analgesia in conscious perching birds.

OBJECTIVE: To develop a technique for objective assessment of modulation of nociperception in conscious perching birds. ANIMALS: 31 adult African grey parrots. PROCEDURE: Birds were randomly assigned to receive saline (0.9% NaCl) solution (n = 10), butorphanol tartrate (11), or buprenorphine hydrochloride (10), i.m. Birds were fitted with a surface electrode on the medial metatarsus of 1 leg. An electrical stimulus was delivered to the bird's foot through an aluminum surface on half of the perch. The alternate side of the perch delivered a noxious thermal stimulus. A withdrawal response to either stimulus was recorded when the bird lifted its foot or vigorously flinched its wings. RESULTS: Responses to thermal stimuli were extremely variable during baseline testing and after administration of drugs. Thus, significant differences were not detected after drug injection. In contrast, responses to an electrical stimulus were predictable with much less variation. CONCLUSIONS AND CLINICAL RELEVANCE: This method and device allowed for the reliable determination of withdrawal threshold in perching birds. Use of this technique for objective assessment of modulation of nociperception in conscious perching birds will enable assessment of analgesic drugs.

Analgesic effects of butorphanol and buprenorphine in conscious African grey parrots (Psittacus erithacus erithacus and Psittacus erithacus timneh).

OBJECTIVE: To evaluate effects of butorphanol tartrate and buprenorphine hydrochloride on withdrawal threshold to a noxious stimulus in conscious African grey parrots. ANIMALS: 29 African grey parrots (Psittacus erithacus erithacus and Psittacus erithacus timneh). PROCEDURE: Birds were fitted with an electrode on the medial metatarsal region of the right leg, placed into a test box, and allowed to acclimate. An electrical stimulus (range, 0.0 to 1.46 mA) was delivered to each bird's foot through an aluminum perch. A withdrawal response was recorded when the bird lifted its foot from the perch or vigorously flinched its wings. Baseline threshold to a noxious electrical stimulus was determined. Birds then were randomly assigned to receive an i.m. injection of saline (0.9% NaCl) solution, butorphanol (1.0 mg/kg of body weight), or buprenorphine (0.1 mg/kg), and threshold values were determined again. RESULTS: Butorphanol significantly increased threshold value, but saline solution or buprenorphine did not significantly change threshold values. CONCLUSIONS AND CLINICAL RELEVANCE: Butorphanol had an analgesic effect, significantly increasing the threshold to electrical stimuli in African grey parrots. Buprenorphine at the dosage used did not change the threshold to electrical stimulus. Butorphanol provided an analgesic response in half of the birds tested. Butorphanol would be expected to provide analgesia to African grey parrots in a clinical setting.

Orbital lymphosarcoma associated with reticuloendotheliosis virus in a peafowl.

Lymphosarcoma associated with infection by avian reticuloendotheliosis virus was diagnosed in an Indian peafowl with exophthalmia and exposure keratitis. Exenteration of the orbit was complicated by a profound oculocardiac reflex and extensive hemorrhage during surgery. Orbital bleeding was controlled by direct pressure, electrocautery, topical administration of bovine thrombin, and application of sterile gelatin sponges and oxidized regenerated cellulose. A blood transfusion was also performed. In addition to describing methods of handling intraoperative complications of orbital exenteration in birds, to the authors' knowledge, this is the first report to describe an association of reticuloendotheliosis virus, which more commonly affects poultry, with lymphosarcoma in an Indian peafowl.

Urgent care of the pet rabbit.

Emergency and critical care principles are similar for all mammals; however, the physiology and natural behavior of rabbits create an animal that is easily stressed and requires specialized handling techniques. This article reviews diagnostic and therapeutic techniques, nutritional support, and pain management for urgent care of pet rabbits. Common differential diagnoses for emergencies are briefly reviewed by the clinical presentation. A table of drug dosages used for urgent care is provided.

Effects of mydriatic agents in cockatoos, African gray parrots, and Blue-fronted Amazon parrots.

OBJECTIVE: To compare, in psittacines, the mydriatic effects of several topically applied curariform, sympathomimetic, and parasympatholytic drugs with and without the addition of surface-acting penetrating agents. DESIGN: Prospective, randomized controlled trial. ANIMALS: 10 adult cockatoos (Cacatua sulphurea subspecies), 2 adult African gray parrots (Psittacus erithacus), and 3 adult Blue-fronted Amazon parrots (Amazona aestiva). PROCEDURE: Three curariform drugs (d-tubocurarine, pancuronium, and vecuronium bromide) and 2 autonomic drugs (atropine and phenylephrine hydrochloride) were evaluated. Drugs were tested with and without the addition of a surface-acting penetrating agent, either saponin or benzalkonium chloride. The agent that resulted in the most significant change in pupillary diameter with the fewest systemic side effects in the cockatoos then was evaluated for its effects in the African gray parrots and the Blue-fronted Amazon parrots. During each drug trial, 1 eye was randomly selected to receive the control drug (0.9% NaCl), and the opposite eye was selected to receive the test drug. Each pupil was videotaped 5 (cockatoos only), 15, 30, 45, 60, and 75 minutes after treatment. Pupil diameters were measured by use of a computerized image analysis system. Data for pupil size were analyzed by means of repeated measures ANOVA. RESULTS: Vecuronium without the addition of a surface-acting penetrating agent produced the most consistent and greatest pupillary dilatation in all 3 species with the fewest systemic side effects. CLINICAL IMPLICATIONS: Vecuronium is potentially a clinically useful, topical mydriatic agent for use in avian species. Documented differences in the prevalence of systemic side effects between species suggests that caution should be applied when applying this drug bilaterally.

Trace element status and free radical defense in elderly rhesus macaques (Macaca mulatta) with macular drusen.

Research into the mechanisms underlying the development of age-related macular degeneration (AMD), the leading cause of visual loss in the United States and Europe in people over 60 years old, has been limited in part by the lack of animal models for this disease. In the current study, we examined 62 elderly (> or = 20 years old) rhesus macaques (Macaca mulatta) for the presence and severity of macular drusen. Drusen were observed in 47% of the macaques; they were similar histologically and in clinical appearance to the drusen observed in humans with AMD. It has been proposed that excessive tissue free radical damage may contribute to the development of AMD. Thus, circulating levels of select components of the free radical defense system and plasma thiobarbituric acid reactive substances (TBARS), an estimate of lipid peroxides, were measured in the above animals. Macaques diagnosed with drusen were characterized by alterations in concentrations and activities of several components of the free radical defense system. Alterations were most evident with respect to those enzymes associated with copper. The concept that excessive oxidative lipid damage might be a factor contributing to the occurrence of this disease is suggested by the findings of higher plasma TBARS concentrations in animals with > 10 drusen compared with animals without drusen.

Determination of the ED50 of isoflurane and evaluation of the isoflurane-sparing effect of butorphanol in cockatoos (Cacatua spp.).

The use of butorphanol as an analgesic in a psittacine species was evaluated by determining its isoflurane-sparing effects. The Effective Dose 50 (ED50) of isoflurane was determined using a bracketing technique based on the purposeful movement elicited by pressure applied to a digit with a hemostat. The ED50 of isoflurane for 11 cockatoos (four greater sulfur crested, three lesser sulfur crested, and four citron crested) was determined to be 1.44 +/- 0.07%. After the administration of 1 mg/kg of butorphanol tartrate intramuscularly (IM), the ED50 was significantly (P < .05) decreased to 1.08 +/- 0.05%. Physiological variables that changed significantly included decreases in heart rate, tidal volume (Vt), inspiratory (Ti) and expiratory times (Te), and an increase in respiratory rate. No complications resulted because of these changes. Based on the results, butorphanol produces an isoflurane-sparing effect in cockatoos and has the potential to be a useful analgesic in psittacines.

Serologic survey and serum biochemical reference ranges of the free-ranging mountain lion (Felis concolor) in California.

Serum samples from 58 mountain lions (Felis concolor) in California (USA) were collected between April 1987 and February 1990. Nineteen serum samples were used for serum biochemistry determinations; the ranges were similar to reference values in domestic cats, captive exotic felidae and free-ranging mountain lions. A serological survey was conducted to determine whether antibodies were present against selected infectious agents. Fifty-four (93%) of 58 sera had antibodies against feline panleukopenia virus. Fifteen (68%) of 22, 16 (28%) of 58, 11 (19%) of 58, and 10 (17%) of 58 had serum antibodies against feline reovirus, feline coronavirus, feline herpes virus, and feline calicivirus, respectively. Twenty-three (40%) of 58 and 21 (58%) of 36 had serum antibodies against Yersinia pestis and Toxoplasma gondii, respectively. Only one of 22 sera had antibodies against the somatic antigen of Dirofilaria immitis. Feline leukemia virus and feline immunodeficiency virus antigens were not detected in any mountain lion's sera. All 58 sera samples were negative for antibodies to feline immunodeficiency virus and Chlamydia psittaci.

Prevalence and risk factors for iron deficiency anemia in weanling rhesus macaques.

Standard epidemiologic methods were used to determine the prevalence and risk factors for iron deficiency at weaning in 143 weanling rhesus macaques (Macaca mulatta) raised indoors at the California Primate Research Center, Davis, CA. Maternal, infant, and management factors were investigated. Prevalence of iron deficiency anemia was 19%, as defined by mean corpuscular volume less than or equal to 66 femtoliters. It was found that animals raised entirely or partially in the nursery had less iron deficiency than dam-reared offspring. Results also suggest multiparous dams were more likely to have iron-deficient weanlings than primiparous dams. These results were discussed in relation to human and nonhuman primate pediatric medicine.

Enrofloxacin treatment of long-tailed macaques with acute bacillary dysentery due to multiresistant Shigella flexneri IV.

Thirty-four cases of acute bacillary dysentery occurred within 90 days among macaques housed at the California Regional Primate Research Center. Cases were identified by depression, diarrhea with blood and leukocytic exudate, and/or leukocytosis with a left shift. Antimicrobial susceptibility testing of enteric isolates and plasmid profile analyses established an etiologic diagnosis of multiple antibiotic resistant Shigella flexneri IV infection. When standard therapies were invalidated by high frequencies of resistance among the isolates, therapy with enrofloxacin, a fluoroquinolone antimicrobial, was initiated to interrupt the epidemic. Serum concentrations of enrofloxacin and its primary metabolite ciprofloxacin were measured in selected cases. A serum concentration-time data analysis was performed to evaluate the oral enrofloxacin dose and dosing interval for nonfasted macaques. Once daily administration of 5 mg/kg enrofloxacin by gastric intubation produced 24-hour serum concentrations above the MICs for the Shigella isolates from this outbreak.

Partial colectomy for treating acquired megacolon in long-tailed macaques.

A syndrome presenting as gross abdominal distension and diagnosed as acquired megacolon was observed in five adult female long-tailed macaques. Gastrointestinal signs included diarrhea, mucus in the stool, anorexia, and failure to pass stool, with repeated episodes of extreme abdominal distension and accumulation of gas and feces in greatly enlarged colons. Medical management was unsuccessful. A partial colectomy with a standard end-to-end colonic anastomosis was performed to remove the section of distended colon in each animal. Histologically, affected colons had degeneration and fibrosis, primarily in the longitudinal layer of the lamina muscularis. Hemograms, serum chemistries, and histopathologic features were not diagnostic of a specific etiology for megacolon. Four of five animals had undergone at least one obstetrical surgery. Two of these had the first episode of colonic distension within 3 days postoperatively. Intra-abdominal adhesions were noted during exploratory surgery in all animals. Three of five had colonic volvulus observed during colectomy. Recovery post-colectomy was uneventful and animals remained free of clinical signs of megacolon.