Parathyroid, Thyroid and Recurrent Laryngeal Nerve Anatomy in an Indian Rhinoceros (Rhinoceros unicornis)

Introduction

The parathyroid gland was first identified in the Indian rhinoceros in 1849 by Sir Richard Owen. We performed a necropsy in an Indian rhinoceros, recapitulating Owen’s dissection and display what appear to be the initial identification of the recurrent laryngeal nerve in situ and the anatomy and histology of the largest rhinoceros parathyroid glands yet identified.

Materials and methods

Patrick T. Rhino, a 41-year-old Indian rhinoceros was born in 1974. His early years were unremarkable. In 2006, he was donated to White Oak Conservation in Yulee, Florida, where he bred and sustained minor injuries. In his geriatric years, he developed a cataract and degenerative joint disease (DJD). At age 41, he developed progressive ataxia and lameness and was euthanized to minimize suffering when he was unable to stand. ROS, FH, SH and medication history were unremarkable. Physical exam was age and species appropriate. Pre-mortem serum demonstrated: creat 1.8 mg/dL (0.8–2.1), calcium 10.6 mg/dL (9.7–13.1), phos 3.8 mg/dL (2.5–6.7), alk phos 69 U/L (26–158) and intact PTH 44.1 pg/mL (rhinoceros reference range: unknown). Necropsy revealed intervertebral DJD with thoracic spondylosis, which combined with osteoporosis, resulted in thoracic myelopathy and ataxia. The neck block was sent in formalin to the Yale University School of Medicine.

Results

Detailed dissection was performed under loupe magnification. Presumed structures were photographed in situ and biopsied. The thyroid was identified deep to the strap muscles, received its blood supply from the inferior and superior thyroid arteries and was blue in color. The right recurrent laryngeal nerve, identified and photographed in situ for the first time in the rhinoceros, was deep to the inferior thyroid artery and was traced throughout its cervical course. Single parathyroid glands identified on the lateral thyroid lobes received their blood supply from the inferior thyroid arteries and were confirmed histologically. They appear to be the largest parathyroids yet identified in the rhinoceros with estimated weights of 6,280 and 11,000 mg, respectively. Although the etiology of the parathyroid gland enlargement is unknown, the specimen has been preserved recapitulating the dissection performed by Sir Richard Owen.

Conclusion

The parathyroids, thyroid and recurrent laryngeal nerve were identified in an Indian rhinoceros. This appears to be the first display of the rhinoceros recurrent laryngeal nerve in situ, and the parathyroid glands are the largest yet identified in the rhinoceros.

Leukoencephalomyelopathy of mature captive cheetahs and other large felids: a novel neurodegenerative disease that came and went?

A novel leukoencephalomyelopathy was identified in 73 mature male and female large captive felids between 1994 and 2005. While the majority of identified cases occurred in cheetahs (Acinonyx jubatus), the disease was also found in members of 2 other subfamilies of Felidae: 1 generic tiger (Panthera tigris) and 2 Florida panthers (Puma concolor coryi). The median age at time of death was 12 years, and all but 1 cheetah were housed in the United States. Characteristic clinical history included progressive loss of vision leading to blindness, disorientation, and/or difficulty eating. Neurologic deficits progressed at a variable rate over days to years. Mild to severe bilateral degenerative lesions were present in the cerebral white matter and variably and to a lesser degree in the white matter of the brain stem and spinal cord. Astrocytosis and swelling of myelin sheaths progressed to total white matter degeneration and cavitation. Large, bizarre reactive astrocytes are a consistent histopathologic feature of this condition. The cause of the severe white matter degeneration in these captive felids remains unknown; the lesions were not typical of any known neurotoxicoses, direct effects of or reactions to infectious diseases, or nutritional deficiencies. Leukoencephalomyelopathy was identified in 70 cheetahs, 1 tiger, and 2 panthers over an 11-year period, and to our knowledge, cases have ceased without planned intervention. Given what is known about the epidemiology of the disease and morphology of the lesions, an environmental or husbandry-associated source of neurotoxicity is suspected.

Surgical resolution of an ectopic pregnancy in a captive gerenuk (Litocranius walleri walleri)

A full-term ectopic pregnancy was diagnosed in a multiparous, captive gerenuk (Litocranius walleri walleri) following prolonged gestation without parturition. Until 213 days of gestation, fetal viability was determined by transabdominal ultrasound of fetal heartbeat, physical palpation, and visual observations of fetal movements. Survey abdominal radiographs obtained at day 229 of gestation revealed a fully mineralized fetal skeleton in an inappropriate position for parturition. Surgical exploration revealed a full-term, nonviable, male calf contained within fetal membranes attached to the omentum. Histologic examination of the fetal membranes identified lesions compatible with placenta-cotyledon separation occurring prior to surgical removal. No congenital fetal abnormalities or infectious processes were identified. Visual observation of the reproductive tract at the time of surgery revealed no abnormalities or evidence of concurrent pregnancy.

Anaesthesia of roan antelope (Hippotragus equinus) with a combination of A3080, medetomidine and ketamine

A dose range was determined for anaesthesia of 20 recently boma-captured roan antelope (Hippotragus equinus) with the synthetic opiate A3080 combined with medetomidine and ketamine. A dose of 10-30 micro/kg A3080 (x = 20+/-8 microg/kg) combined with 5-21 microg/kg medetomidine (x = 13+/-7 microg/kg) plus 0.29-1.11 mg/kg ketamine (x = 0.71+/-0.24 mg/kg) was found to be safe and effective for the field conditions in this study. The anaesthesia produced by this drug combination was predictable and characterised by a short induction time, good muscle relaxation, and acceptable physiological parameters for anaesthesia periods ranging from 49-103 min (x = 64+/-19 min). The wide range (3-4-fold) of doses with acceptable results is also an indication that this drug combination has a wide margin of safety in roan antelope, making it desirable for field use. When 2 dose levels (2-3-fold dif ference) were retrospectively evaluated, no statistical difference was found in induction times, and no observable clinical differences in the anaesthetic episodes were seen. Based on this study, the recommended dose range in roan antelope for this combination is 10-13 microg/kg A3080, 5-6 microg/kg medetomidine and 0.3-0.6 mg/kg ketamine. The anaesthesia produced by this combination was rapidly and completely reversed by i.m. or i.v. injections of naltrexone at 30 times the A3080 dose (x = 0.60+/-0.25 mg/kg) and atipamezole at 3 times the medetomidine dose (x = 38+/-20 microg/kg). No residual effects from ketamine were noted following reversal of A3080 and medetomidine. No mortality was associated with this protocol.

Diverticulitis with rupture and fatal peritonitis in a Sumatran orangutan (Pongo pygmaeus)

A 30-year-old male Sumatran orangutan (Pongo pygmaeus) presented with signs of depression, lethargy, anorexia, and diarrhea that progressed to acute colic. Exploratory laparotomy revealed fibrinopurulent peritonitis and 50 cm of devitalized small intestine. The surgically resected small intestine contained several mucosal diverticula along the mesenteric attachment; one had ruptured, resulting in peritonitis. Fifteen days after surgery, the orangutan's abdominal incision dehisced. Repeated laparotomy revealed dehiscence of the distal intestinal anastomosis site, as well as extensive adhesions and purulent exudate. The defect was repaired, and the abdomen was extensively irrigated and closed, but the animal died within 24 hours. To our knowledge, this is the first report of diverticulitis in a great ape. Diverticulosis should be considered in the differential diagnosis for great apes that present with signs of depression, lethargy, anorexia, and/or diarrhea.

Fecal cortisol metabolite analysis for noninvasive monitoring of adrenocortical function in the cheetah (Acinonyx jubatus)

A radioimmunoassay was validated for quantifying excreted cortisol metabolites in cheetah (Acinonyx jubatus) feces. High-performance liquid chromatography analysis indicated that immunoreactivity was associated with a water-soluble metabolite in fecal extracts from males and females. None of the immunoreactivity corresponded with free cortisol or corticosterone but rather was associated with a more polar, unidentified metabolite. To determine the biologic relevance of excreted immunoreactive cortisol metabolites, cheetahs were exposed to a variety of situations anticipated to increase cortisol secretion. First, to assess acute changes in adrenal activity, adrenocorticotropic hormone (ACTH; 400 IU i.m.) was administered to two adult males and two adult females. Pre-ACTH baseline serum cortisol and fecal cortisol metabolite concentrations varied among individuals. Serum cortisol concentrations were elevated above baseline within 10 min of ACTH injection, followed by corresponding increases in fecal cortisol metabolite concentrations (690-4,194% above baseline) 48 hr later in three of four cheetahs. In the fourth cheetah, a smaller increase (334% above baseline) in fecal cortisol metabolite excretion was observed 96 hr after ACTH injection. Seven cheetah females also were subjected to a variety of potentially stressful manipulations, including immobilization, translocation, and introduction to a male to assess the ability of this technique to detect physiologic changes in adrenal activity. Increased fecal corticoid metabolite excretion was observed 24-72 hr after exposure to these exogenous stressors. Results indicate that adrenocortical activity can be monitored noninvasively in the cheetah through analysis of these metabolites. This technique could be valuable for evaluating, and thus optimizing, environmental and management conditions and for investigating the role of stress in disease pathogenesis and the usually poor reproductive performance of this species in captivity.

Atrial septal defects in Florida panthers

Ostium secundum atrial septal defects (ASDs) were observed in six (3 M, 3 F) of 33 (20 M, 13 F) (18%) Florida panthers (Puma concolor coryi) necropsied by veterinary pathologists between 1985 and 1998. A seventh ASD was found in a female panther necropsied in the field and is included in the pathological description but not the prevalence of ASDs in Florida panthers. One panther (FP205) with severe ASD also had tricuspid valve dysplasia (TVD). Atrial septal defects and/or TVD are believed to have caused or contributed to the deaths of three (9%) Florida panthers in this study. Mean diameter +/- SD of ASDs was 9.0 +/- 4.7 mm (range 3 to 15 mm). Gross pathological changes attributed to ASDs/TVD in severely affected panthers (ASD > or = 10 mm) (n = 4) included mild right ventricular dilatation (n = 3) and hypertrophy (n = 2), mild to severe right atrial dilatation (n = 2), and acute pulmonary edema (n = 3). Panthers with mild ASDs (ASD < or = 5 mm) (n = 3) had no other detectable gross pathological changes associated with the ASDs. Histological examination of lungs of three panthers with severe ASDs revealed mild to moderate dilatation with fibrosis and smooth muscle atrophy of the tunica media of medium to large caliber arteries (n = 2), interstitial and/or pleural fibrosis (n = 2), perivascular fibrosis (n = 1), and acute to chronic edema (n = 3). Twenty-six necropsied panthers were examined one or more times while living; medical records were retrospectively evaluated. Antemortem radiographic, electrocardiographic, and echocardiographic examinations were performed on two panthers with severe ASDs (FP20 and FP205). Thoracic radiographic abnormalities in both included right heart enlargement, and in FP205 (severe ASD and TVD), mild pulmonary overperfusion. Electrocardiographic examination of FP205 revealed a right ventricular hypertrophy pattern, while FP205 had a normal electrocardiogram. Echocardiographic examination of FP20 revealed marked right atrial dilatation; a bubble contrast study indicated regurgitation across the tricuspid valve. Echocardiographic abnormalities in FP20 included right atrial and ventricular lilatation, atrial septal drop-out, and severe tricuspid regurgitation; non-selective angiography revealed significant left to right shunting across the ASD. All panthers with severe ASDs ausculted (n = 3) had systolic right or left-sided grade I-V/VI murmurs loudest at the heart base. All male panthers with ASDs (n = 3) (100%) and 9 of 17 (53%) male panthers without ASDs in this study were cryptorchid.

Dermatophyte infections in free-ranging Florida panthers (Felis concolor coryi)

Three free-ranging Florida panthers (Felis concolor coryi) were diagnosed with clinical dermatophytosis; two were infected with Trichophyton mentagrophytes, and one was infected with Microsporum gypseum. Two of these panthers were juvenile males that were diagnosed with focal to focally coalescing dermatophytosis; one caused by M. gypseum and the other by T. mentagrophytes. These animals were not treated, and clinical signs resolved spontaneously over 6 mo. The third panther, an adult male from southern Florida, presented with a diffuse dermatophytosis due to T. mentagrophytes infection. Initially, the panther had alopecia, excoriations, ulcerations, and multifocal pyoderma of the head, ears, neck, rear limbs, and abdominal region that progressed to lichenification of the skin and loss of nails from two digits. When topical therapy applied in the field at 45-day intervals was ineffective in clearing the infection, the animal was placed in captivity for intensive oral therapy to prevent further development of dermal mycosis, loss of additional nails, and spread of infection to other panthers. The panther was treated orally with itraconazole (9.5 mg/ kg) in the food s.i.d. for 6 wk. After treatment, nail regrowth occurred but the multifocal areas of alopecia remained. The panther was released back into the wild after two skin biopsy cultures were negative for fungal growth. Temporary removal of a free-ranging animal of an endangered species from its habitat for systemic treatment of dermatophytosis requires consideration of factors such as age, reproductive potential, holding facilities, treatment regimen, and the potential for successful reintroduction of the animal.

Anesthetic and cardiorespiratory effects of tiletamine-zolazepam-medetomidine in cheetahs

OBJECTIVE

To evaluate anesthetic and cardiorespiratory effects of an intramuscular injection of a tiletamine-zolazepam-medetomidine combination in cheetahs.

DESIGN

Prospective study.

ANIMALS

17 adult captive cheetahs.

PROCEDURE

The anesthetic combination was administered intramuscularly via a dart. Induction quality, duration of lateral recumbency, duration of recovery, and quality of anesthetic reversal with atipamezole were assessed. Cardiorespiratory variables (arterial blood gas partial pressures, arterial blood pressure, heart and respiratory rates, end-tidal CO2, oxygen saturation, and rectal temperature) were measured during anesthesia.

RESULTS

Sedation and lateral recumbency developed within 1.9 +/- 1.0 (mean +/- SD) and 4.3 +/- 2.0 minutes of drug administration, respectively. Clinically acceptable cardiorespiratory and blood gas values were recorded for at least 87 minutes after drug administration in all but 1 cheetah. Hypoxemia and arrhythmias developed in 1 cheetah breathing room air but resolved after treatment with oxygen. Hypertension developed in all cheetahs. Significant differences in heart and respiratory rates, mean arterial blood pressure, arterial pH, partial pressure of oxygen, and hemoglobin saturation were found between cheetahs that did and did not receive oxygen supplementation. After administration of atipamezole, sternal recumbency and mobility returned within 6.9 +/- 5.8 and 47.5 +/- 102.2 minutes, respectively. Postreversal sedation, which lasted approximately 4 hours, developed in 4 cheetahs.

CLINICAL IMPLICATIONS

Tiletamine-zolazepam-medetomidine delivered via a dart provided an alternative method for induction and maintenance of anesthesia in cheetahs. Atipamezole at the dose used was effective for reversal of this combination in the initial phase of anesthesia.

Cardiopulmonary and anesthetic effects of propofol in wild turkeys

OBJECTIVE

To determine safety, anesthetic variables, and cardiopulmonary effects of i.v. infusion of propofol for induction and maintenance of anesthesia in wild turkeys.

ANIMALS

10 healthy, adult wild turkeys.

PROCEDURE

Anesthesia was induced by i.v. administration of propofol (5 mg/kg of body weight) over 20 seconds and was maintained for 30 minutes by constant i.v. infusion of propofol at a rate of 0.5 mg/kg/min. Heart and respiratory rates, arterial blood pressures, and arterial blood gas tensions were obtained prior to propofol administration (baseline values) and again at 1, 2, 3, 4, 5, 10, 15, 20, 25, and 30 minutes after induction of anesthesia. All birds were intubated immediately after induction of anesthesia, and end-tidal CO2 concentration was determined at the same time intervals. Supplemental oxygen was not provided.

RESULTS

Apnea was observed for 10 to 30 seconds after propofol administration, which induced a decrease in heart rate; however, the changes were not significant. Compared with baseline values, respiratory rate was significantly decreased at 4 minutes after administration of propofol and thereafter. Systolic, mean, and diastolic pressures decreased over the infusion period, but the changes were not significant. Mean arterial blood pressure decreased by 30% after 15 minutes of anesthesia; end-tidal CO2 concentration increased from baseline values after 30 minutes; PO2 was significantly decreased at 5 minutes after induction and thereafter; PCO2 was significantly (P < 0.05) increased after 15 minutes of anesthesia; and arterial oxygen saturation was significantly (P < 0.05) decreased at the end of anesthesia. Two male turkeys developed severe transient hypoxemia, 1 at 5 and the other at 15 minutes after induction. Time to standing after discontinuation of propofol infusion was 11 +/- 6 minutes. Recovery was smooth and unremarkable.

CONCLUSION

Propofol is an effective agent for i.v. induction and maintenance of anesthesia in wild turkeys, and is useful for short procedures or where the use of inhalational agents is contraindicated.

Cardiopulmonary effects of carfentanil in dama gazelles (Gazella dama)

Sixteen (10 female, six male) captive-born dama gazelles (Gazella dama) weighing 48 +/- 10 kg (mean +/- SD) were used to evaluate the cardiopulmonary effects of i.m. carfentanil and to validate the use of pulse oximetry in immobilized gazelles. Carfentanil (18.4 +/- 2.2 micrograms/kg i.m.) produced rapid induction (6 +/- 3 min), moderate muscle relaxation, and a significant (P < 0.05) decrease in heart rate (87 +/- 12 beats/min) beginning 5 min following induction and continuing throughout the immobilization period. A decrease in respiratory rates began 15 min following induction (11 +/- 4 breaths/min). Systemic hypertension was present throughout the immobilization period. Arterial blood gas analysis, performed at 10, 20, and 30 min after induction, showed PaCO2 and PaO2 values within normal limits. Arterial blood oxygen saturation (SaO2) was < 95% 10 min after induction. Relative arterial oxygen saturation (SpO2) values indicated by pulse oximetry were generally lower than SaO2 values but reliably demonstrated trends in arterial oxygen saturation as confirmed by arterial blood gas analysis. Periods of hypoxemia were usually indicated by the pulse oximeter reading and confirmed by SaO2 measurements. There was an increase in creatine phosphokinase values (88 +/- 53 U/L to 109 +/- 48 U/L) at 30 min postimmobilization. Naltrexone reversal (1.8 +/- 0.3 mg/kg, half i.v. and half s.c.) was rapid and uneventful, and time to standing was 2 +/- 1 min.

Effects of a carfentanil-xylazine combination on cardiopulmonary function and plasma catecholamine concentrations in female bongo antelopes

OBJECTIVE

To determine the effects of an i.m. administered carfentanil-xylazine combination on cardiopulmonary variables and plasma catecholamine concentrations and to validate use of pulse oximetry in bongo antelopes.

ANIMALS

8 healthy adult females.

PROCEDURE

Antelopes were immobilized with carfentanil citrate (8.3 micrograms/kg of body weight, i.m.) and xylazine hydrochloride (0.79 mg/kg, i.m.). Hematologic values and plasma biochemical and catecholamine concentrations were determined at the beginning and end of immobilization. Immediately after induction of immobilization and every 15 minutes thereafter, cardiopulmonary variables were determined.

RESULTS

Induction time after carfentanil-xylazine administration was 6 +/- 2 minutes. At 15 and 45 minutes after immobilization and thereafter, significant decrease in heart and respiratory rates, respectively, were observed. After 15 minutes of immobilization, all antelopes had developed mild hypoxemia, which resolved after nasal insufflation with 100% oxygen. Pulse oximetry readings underestimated arterial blood gas values, but reliably indicated trends in arterial oxygen desaturation. Antelopes developed hypoxemia after oxygen administration was terminated at the end of the procedure, prior to reversal of immobilization. Norepinephrine concentrations increased significantly (P < 0.05), and 3,4-dihydroxyphenylacetic acid concentrations decreased significantly at the end of the anesthetic event. Immobilization of all antelopes was reversed, using antagonists naltrexone and yohimbine hydrochloride. Time to standing was 3 +/- 1 minutes, and renarcotization was not observed.

CONCLUSIONS AND CLINICAL RELEVANCE

The carfentamil-xylazine combination at the dosage used induced hypoxemia, pronounced arterial hypertension, and significant increase in plasma norepinephrine and decrease in plasma 3,4-dihydroxyphenylacetic acid concentrations in bongo antelopes. Supplemental administration of oxygen is recommended. Pulse oximetry is a useful tool to monitor trends in arterial oxygen desaturation, but does not substitute for arterial blood gas analysis.

Dubin-Johnson-like syndrome in golden lion tamarins (Leontopithecus rosalia rosalia)

On routine blood screens, persistent conjugated hyperbilirubinemia was discovered in two groups of closely related adult female golden lion tamarins (Leontopithecus rosalia rosalia, n = 8). Bromosulfophthalein (BSP) retention tests were performed on four hyperbilirubinemic and three control tamarins. BSP excretion was delayed in hyperbilirubinemic tamarins as compared with controls. Grossly, liver of affected tamarins was dark brown to black, with a prominent reticulated pattern. Histologic examination revealed abundant intrahepatic pigment, primarily in a centrilobular and midzonal distribution. Most of the pigment did not react with Perls' Prussian blue method for iron, Hall's method for bilirubin, or the Armed Forces Institute of Pathology acid-fast method for lipofuscin but was positive with Fontana and lipofuscin-ferric ferricyanide reduction techniques. Liver from control golden lion tamarins had intrahepatocellular Perls' iron-positive pigment diffusely throughout the lobule with a small amount of Fontana method-positive pigment. Ultrastructurally, hepatocytes from a hyperbilirubinemic tamarin contained pleomorphic electron-dense structures within lysosomes. Transport studies demonstrated secretion of fluorescein isothiocyanate-labeled glycocholic acid, a fluorescent bile acid analog, into bile canaliculi and no secretion of carboxydichlorofluorescein diacetate, a non-bile acid organic anion, by liver from a hyperbilirubinemic tamarin. In contrast, control liver secreted carboxydichlorofluorescein diacetate readily into bile canaliculi. The clinicopathologic presentation of this syndrome in golden lion tamarins is similar to that described for Dubin-Johnson syndrome of human beings.

Seasonal variation in pituitary-gonadal function in free-ranging impala (Aepyceros melampus)

Blood, testicular biopsies and electroejaculates were collected from adult male impala, free-ranging in the Kruger National Park (Republic of South Africa), during the breeding (rut; April-May) and nonbreeding (September-October) seasons. Blood samples were collected at 5-min intervals for 120 min from anaesthetized males (n = 7 impala/group) treated intravenously with saline, gonadotrophin-releasing hormone (GnRH: 1 microgram/kg body weight) or human chorionic gonadotrophin (hCG: 10 or 30 iu/kg). Semen was collected from six more animals during the breeding season and 12 animals during the nonbreeding season using a standardized electroejaculation protocol. Ejaculates obtained during the nonbreeding season were of inferior quality to those collected during the breeding season, and were characterized by lower sperm concentrations, poorer sperm motility and more morphologically abnormal sperm forms. Within season, there were no differences in testosterone secretion between the two hCG doses, and these responses were similar to those observed after GnRH, but during the rut, testosterone secretion stimulated by both GnRH and hCG was approximately nine times greater than during the nonbreeding season. This seasonal increase in testosterone production was associated with a doubling in testicular volume and concentrations of luteinizing hormone (LH) receptors. Although concentrations of testicular follicle-stimulating hormone (FSH) receptors were similar between seasons, receptor content increased during rut as a result of increased testicular volume. In contrast to testosterone secretion, basal LH and FSH secretions were unaffected by season and GnRH-induced gonadotrophin secretion was reduced during rut.(ABSTRACT TRUNCATED AT 250 WORDS)

Salivary gland oncocytes in African hedgehogs (Atelerix albiventris) mimicking cytomegalic inclusion disease

The salivary glands from three African hedgehogs contained multiple foci of cytomegalic cells, which occasionally had a mild to moderate infiltrate of lymphocytes at the periphery. The cytomegalic cells were 35 to 40 microns in diameter with abundant acidophilic granular to hyalin cytoplasm. The nuclei were enlarged with clumped marginalized chromatin and a large, (6 to 8 microns in diameter) central, brightly eosinophilic nucleolus that had the appearance of an inclusion body by light microscopy. Histochemically most of the cytomegalic cells contained cytoplasmic metachromatic granules with Feyrter's thionine inclusion stain. Scattered cells at the periphery of the cytomegalic foci contained periodic acid-Schiff-positive cytoplasmic granules. Ultrastructurally the cytomegalic cells contained numerous tightly-packed, often bizarre, enlarged mitochondria that completely filled the cytoplasm. The nucleus consisted of a dense central core of chromatin associated with the nucleolus and the remaining chromatin was clumped and marginalized. Nuclear and cytoplasmic virions consistent with cytomegalovirus were not present. Histochemical stains of the nucleus for heavy metals were negative. The ultrastructural and histochemical findings of the cytomegalic cells were consistent with oncocytes. Previous reports in the literature of similar cells in the salivary glands of insectivores appear to have been erroneously described as cytomegalovirus infections.

Impact of season on seminal characteristics and endocrine status of adult free-ranging African buffalo (Syncerus caffer)

Pituitary, gonadal and adrenal activity were compared in free-living, adult African buffalo bulls during the breeding and nonbreeding seasons. Frequent blood samples were collected for 2 h from anaesthetized bulls treated intravenously with saline, gonadotrophin-releasing hormone (GnRH, 200 micrograms), human chorionic gonadotrophin (hCG, 10,000 i.u.) or adrenocorticotrophic hormone (ACTH, 1.5 mg). Electroejaculates also were collected from anaesthetized bulls during the breeding and nonbreeding seasons. Pretreatment testosterone concentrations among bulls varied more during the breeding (0.17-23.0 ng/ml) than the nonbreeding (0.15-2.21 ng/ml) season. The variation within the breeding season was attributed to 8 of 25 bulls producing higher (P less than 0.05) serum testosterone (High-T; 16.28 +/- 2.03 ng/ml) and testicular LH receptor (1.53 +/- 0.22 fmol/mg testis) concentrations compared with their seasonal counterparts (Low-T; 0.95 +/- 0.26 ng/ml; 0.38 +/- 0.04 fmol/mg) or with all bulls during the nonbreeding season (0.90 +/- 0.27 ng/ml; 0.31 +/- 0.04 fmol/mg). The magnitude of GnRH- and hCG-induced increases in serum testosterone was similar (P greater than 0.05) between Low-T bulls and bulls during the nonbreeding season. In the High-T animals treated with GnRH or hCG, serum testosterone did not increase, suggesting that secretion was already maximal. Peak serum LH concentrations after GnRH were greater (P less than 0.05) in bulls during the nonbreeding than the breeding season; FSH responses were similar (P greater than 0.05). ACTH treatment did not increase serum cortisol concentrations above the 2-fold increase measured in bulls treated with saline, hCG and GnRH (P greater than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Circulating plasma alpha-tocopherol following a single injection in a black rhinoceros (Diceros bicornis)

Injectable all rac-alpha-tocopherol, at a dose of 12.4 IU/kg body mass, increased circulating levels of alpha-tocopherol in the black rhinoceros (Bicornis diceros) from 0.18 microgram/ml to 1.47 micrograms/ml within 2 hr. Although the plasma level peaked at Day one (13.07 micrograms/ml) and dropped rapidly, substantial residual effects were seen even 10 days (1.50 micrograms/ml) following a single injection. It appears that parenteral vitamin E administration may be suitable for therapeutic treatment of vitamin E deficiency in the black rhinoceros.

Use of a subunit feline leukemia virus vaccine in exotic cats

Three adult bengal tigers, 2 immature white tigers, and 3 adult servals were vaccinated IM with three 1-ml doses of a subunit FeLV vaccine with dosage interval guidelines of the manufacturer. All cats had increased antibody titers to FeLV gp 70 capsular antigen and feline oncornavirus cell membrane-associated antigen during the vaccination trial. Three weeks after the third vaccination, 7 of the 8 cats had gp70 antibody titers greater than 0.2 (optical density), and all 8 cats had feline oncornavirus cell membrane-associated antigen antibody titers greater than 1:8.

Tropical fish medicine. Providing veterinary care to the commercial fish farmer

The veterinarian with experience in preventive and herd health medicine is in a unique position to help the tropical fish farmer reduce losses and increase profits. This goal can best be accomplished through a comprehensive medical consultation program involving both problem-oriented and preventive medicine.

A malignant nephroblastoma in an aged fox (Fennecus zerda)

A malignant nephroblastoma with pulmonary metastasis which was found at necropsy in an old fox is described. This is the first report of such a tumour in a fox. Nephroblastoma is rare in the family Canidae and usually occurs in young individuals. The presence of a tumour arising from embryonal tissue in an aged animal raises questions about the genesis and behaviour of this tumour. The tumour may have contributed to the animal's congestive heart failure as a result of the generalized pulmonary involvement, an erythropoietin-induced polycythaemia, or increased peripheral resistance via the renin-angiotensin system.

Four cases of neoplasia in captive wild birds

Four cases of malignant neoplasia in captive wild birds are described: an adenocarcinoma of the adrenal gland in a Mountain duck (Tadorna tadornoides), a malignant melanoma in the thoracic cavity of a Combed duck (Sarkidiornis melanotos), a hepatocellular carcinoma with pulmonary metastasis in an Asian Purple Swamphen (Porphyrio porphyrio), and an undifferentiated carcinoma in the abdomen with metastasis to skeletal muscle in a White-Breasted Waterhen (Amaurornis phoenicurus). The tumors were diagnosed during a 1-year period and represented an incidence of neoplasia of 3.1%. These appear to be the first documented cases of a malignant adrenal gland tumor and a non-ocular melanoma in the order Anseriformes. The hepatocellular carcinoma failed to react with an immunoperoxidase stain for alphafetoprotein.