Unusual immunophenotype of a soft tissue sarcoma in a European polecat (Mustela putorius)

The most commonly reported tumors in ferrets are carcinomas, followed by round cell tumors. Soft tissue sarcomas are reported and characterized much less frequently. Because domesticated ferrets (Mustela putorius furo) are direct descendants of European polecats (Mustela putorius), the types and prevalence of tumors are expected to be similar in the two species. Presented here is a case report of unusual immunohistochemical staining characteristics of an abdominal wall leiomyosarcoma in a close relative of domestic ferrets, the European polecat. Sections of tissue were preserved in 10% buffered formalin, embedded in paraffin, and sectioned at 5 mm. Routine staining with hematoxylin and eosin and several immunohistochemical tests were performed to identify the tumor tissue of origin. Although the tumor did not stain with antibody to desmin, further staining for smooth muscle actin was consistent with a smooth muscle origin. To the authors' knowledge, this report is the first description of a leiomyosarcoma in the European polecat. This report emphasizes the importance of using additional secondary markers to accurately diagnose anaplastic tumors.

Potentiation of metastasis by cell surface sialomucin complex (rat MUC4), a multifunctional anti-adhesive glycoprotein

Sialomucin complex (SMC), a rat homologue of the human mucin MUC4, is a large membrane-bound mucin complex, originally isolated from highly metastatic ascites 13762 mammary adenocarcinoma cells. When overexpressed, SMC exerts potent anti-adhesive effects, which sterically disrupt molecular interactions for cell-cell and cell-ECM adhesions. SMC similarly suppresses anti-tumor immunity by inhibition of interactions between cytotoxic lymphocytes and target tumor cells. Previously, recombinant cDNAs for SMC were transfected and inducibly expressed in A375 human melanoma cells using a tetracycline-responsive expression system. In the current studies, we investigated the role of MUC4/SMC in tumor metastasis by regulating SMC expression of tumor transplants in vivo. Intravenous injection of SMC-overexpressing cells resulted in substantially greater lung metastasis than injection of SMC-repressed cells. Injection of SMC-overexpressing cells followed by in vivo downregulation of SMC did not lower the frequency of lung metastasis. Growth of the micrometastatic lesions was the same for all 3 cases in short-term (3-week) assays. Further, subcutaneous injection of A375 cells followed by in vivo induction of SMC overexpression within the solid tumor resulted in spontaneous distant metastasis. These studies suggest that SMC potentiates metastasis by contributing to the establishment of metastatic foci. These studies directly demonstrate for the first time that tumor metastasis can be modulated by the regulation of MUC4/SMC expression.

Potentiation of metastasis by cell surface sialomucin complex (rat MUC4), a multifunctional anti-adhesive glycoprotein

Sialomucin complex (SMC), a rat homologue of the human mucin MUC4, is a large membrane-bound mucin complex, originally isolated from highly metastatic ascites 13762 mammary adenocarcinoma cells. When overexpressed, SMC exerts potent anti-adhesive effects, which sterically disrupt molecular interactions for cell-cell and cell-ECM adhesions. SMC similarly suppresses anti-tumor immunity by inhibition of interactions between cytotoxic lymphocytes and target tumor cells. Previously, recombinant cDNAs for SMC were transfected and inducibly expressed in A375 human melanoma cells using a tetracycline-responsive expression system. In the current studies, we investigated the role of MUC4/SMC in tumor metastasis by regulating SMC expression of tumor transplants in vivo. Intravenous injection of SMC-overexpressing cells resulted in substantially greater lung metastasis than injection of SMC-repressed cells. Injection of SMC-overexpressing cells followed by in vivo downregulation of SMC did not lower the frequency of lung metastasis. Growth of the micrometastatic lesions was the same for all 3 cases in short-term (3-week) assays. Further, subcutaneous injection of A375 cells followed by in vivo induction of SMC overexpression within the solid tumor resulted in spontaneous distant metastasis. These studies suggest that SMC potentiates metastasis by contributing to the establishment of metastatic foci. These studies directly demonstrate for the first time that tumor metastasis can be modulated by the regulation of MUC4/SMC expression.

Hematologic, plasma protein, and biochemical profiles of brown pelicans (Pelecanus occidentalis)

OBJECTIVE

To establish hematologic and biochemical reference values for the brown pelican (Pelecanus occidentalis).

ANIMALS

31 captive, healthy, but permanently disabled pelicans and 35 wild-caught, healthy pelicans from a rehabilitation facility on the east coast of Florida.

PROCEDURES

Samples of venous blood were collected from each pelican, and hematologic, plasma biochemical, and electrophoretic protein analyses were performed. Student t-tests were used to compare blood values between captive versus wild-caught, adult male versus adult female, and adult versus juvenile pelicans.

RESULTS

Hematologic and electrophoretic values were similar between male and female, adult and juvenile, and captive and wild-caught pelicans. Significant sex differences existed for plasma calcium and triglyceride concentrations. Plasma concentrations of calcium, cholesterol, and CO2 content differed between captive and wild-caught adults. No significant differences were found between wild-caught adult and juvenile pelicans.

CONCLUSIONS AND CLINICAL RELEVANCE

Our plasma biochemical results are similar to those of other brown pelicans and confamilial species. Additional studies on seabirds are encouraged, as age, sex, reproductive status, feeding habits, and captivity are important variables for health assessment in this and other aquatic species.

Medium-sized business employees speak out about smoking

A health promotion study, funded by a state health department to meet objectives 3.4 and 3.11 of Healthy People 2000, was designed to: (1) identify tobacco use; (2) assess employees' beliefs on one's health and family member's health; and (3) assess the type of smoking policies favored. Using the Health Belief Model, it was hypothesized that there were differences in the health beliefs of tobacco users, former users, and never users. A 34-item questionnaire was administered to 1090 employees with a return rate of 603 (55%).

RESULTS

tobacco users perceived weight control and reduction of tension as benefits; they accepted warning label as hazardous but reported smokeless not as harmful; they perceived heart disease and cancer as related to tobacco use; and 62% had tried to quit smoking. Former and never users wanted "total ban policies" while, tobacco users wanted "designated areas" for smoking. All perceived their smoking and environmental tobacco smoke hazardous to their health and the health of family.

Prostate cancer progression, metastasis, and gene expression in transgenic mice

We previously reported that a transgenic mouse line containing the fetal globin promoter linked to the SV40 T antigen (T Ag) viral oncogene (Ggamma/T-15) resulted in prostate tumors. In this study, we further explored tumor origin, frequency, invasiveness, androgen sensitivity, and gene expression pattern. T Ag was detected in adult but not fetal and neonatal prostates, suggesting a role for androgens in tumor progression. However, castration shortly after prostate morphogenesis did not prevent tumor development, suggesting an androgen-independent phenotype. Tumors originated within ventral or dorsal prostate lobes and involved intraepithelial neoplasia, rapid growth in the pelvic region, and metastasis to lymph nodes and distant sites. In addition, the primary cancers could be propagated in nude mice or nontransgenic mice. Seventy-five percent of hemizygous and 100% of homozygous transgenic males developed prostate tumors, suggesting a T Ag dosage effect. Biochemical characterization of advanced tumors revealed markers of both neuroendocrine and epithelial phenotypes; markers of terminal differentiation are lost early in tumorigenesis. Tumor suppressor genes (p53 and Rb), normally bound to T Ag, were up-regulated; bcl-2 proto-oncogene, which prevents apoptosis, was slightly up-regulated. Myc, a stimulus to cell cycle progression, was unchanged. We propose the Ggamma/T-15 transgenic line as a model of highly aggressive androgen-independent metastatic prostate carcinoma with features similar to end-stage prostate cancer in humans.

Macrophage inhibitory factor-A3 derived from Mycobacterium avium serovar 2 inhibits candidacidal activity of murine peritoneal macrophages

Macrophage inhibitory factor-A3 (MIF-A3), a fraction derived from Mycobacterium avium serovar 2 inhibited candidacidal activity in macrophages from C57BL/6, C57BL/10, C3H/HeJ and A/J strains of mice. Inhibition of candidacidal activity was demonstrated at MIF-A3 concentrations ranging from 100-400 micrograms/ml in macrophages without additional stimulators (exception C3H/HeJ macrophages) and in macrophages additionally stimulated with 200 U/ml interferon-gamma, 100 ng/ml phorbol myristate acetate and 0.4 ng/ml E. coli lipopolysaccharide from all mouse strains tested. The decreased candidacidal effect produced by MIF-A3 was dose-dependent and appeared greatest in macrophages treated with phorbol myristate acetate and lipopolysaccharide. This effect was neutralized by the addition of goat anti-MIF-A3 antiserum. Macrophages from the Bcgs mouse strains (C57BL/6 and C57Bl/100 were more sensitive to the effect(s) of MIF-A3 than macrophages from the Bcgr mouse strains (C3H/HeJ and A/J).

The role of cell-mediated cytotoxicity in acute GVHD after MHC-matched allogeneic bone marrow transplantation in mice

The role of cell-mediated cytotoxicity in the complex pathophysiology of graft-versus-host disease (GVHD) has remained poorly defined for several decades. We transplanted T cells from Fas-ligand (FasL)-defective and perforin-deficient mutant donor mice into lethally irradiated MHC-matched allogeneic recipient mice to characterize the role of cell-mediated cytotoxicity in GVHD. Although recipients of allogeneic FasL-defective donor T cells underwent severe GVHD-associated cachexia, they exhibited only minimal signs of hepatic and cutaneous GVHD pathology. Recipients of perforin-deficient allogeneic donor T cells developed signs of acute GVHD, but the time of onset was significantly delayed. These findings demonstrate that Fas-mediated anti-recipient cytotoxicity may be critical for the development of hepatic and cutaneous GVHD, but is not required for GVHD-associated cachexia. In addition, perforin-mediated anti-recipient cytotoxicity appears to play an important role in the kinetics of GVHD pathophysiology, but is not required for GVHD-associated tissue damage.

Prostate, adrenocortical, and brown adipose tumors in fetal globin/T antigen transgenic mice

Targeted oncogenesis in transgenic mice has unexpectedly produced predictable tissue-specific tumors. We previously showed that hybrid gene constructs of the human fetal G gamma- or mouse embryonic beta h1-globin promoter linked to the viral simian virus 40 T antigen (G gamma/T and beta h1/T) expressed appropriately in embryonic erythroid tissue, with some unexpected expression elsewhere. Tumors arising in the G gamma/T and beta h1/T transgenic mice were identified by histology, electron microscopy, cell culture, and RNase protection analyses. In one G gamma/T transgenic line, males developed prostate tumors that showed mixed neuroendocrine and epithelial cell features, whereas females developed adrenocortical tumors. In several other G gamma/T lines, brown adipose tumors, or hibernomas, developed in the subcutaneous interscapular neck and shoulder area, as well as internally in the periadrenal and pericardial areas. Little or no expression of T antigen was detected in adult animals before visible tumor formation. In contrast, beta h1/T transgenic mice developed only choroid plexus tumors. Transient transfection assays in prostate and adrenocortical tumor-derived cell lines showed that the G gamma-globin promoter is 7-to 10-fold more active than the beta h1-globin promoter. Activity of 5' G gamma-globin promoter-deletion DNA plasmids was analyzed by transient transfection in a variety of human prostate cancer cell lines. The G gamma-globin promoter region between -140 and -201 also showed high activity in the androgen-independent human prostate cancer cell lines DU-145 and PPC-1, but low activity in the androgen-responsive human prostate cell line LNCaP. We conclude that tumor formation in the G gamma/T transgenic lines apparently results from cryptic positive DNA cis elements active in prostate and adrenocortical cells. Because G gamma-globin promoter activity is highest in embryonic tissue, tumors in adult transgenic mice may result from expression of T antigen in embryonic prostate, adrenal glands, and brown adipose tissue.

Metastatic malignant melanoma in a mandarin duck (Aix galericulata)

A biopsy taken from a mass on the dorsal surface of the bill of an adult female mandarin duck (Aix galericulata) was diagnosed as a malignant melanoma by light microscopy. Two months later, the tumor had enlarged considerably; the duck developed severe dyspnea and was euthanatized. At necropsy, there were metastases to lymphoid tissues in the lower regions of the neck. To our knowledge, this is the first report of a malignant melanoma in a mandarin duck.

In vitro and long-term in vivo immune dysfunction after infection of BALB/c mice with mouse hepatitis virus strain A59

Mouse hepatitis virus (MHV) is a pervasive pathogen in most mouse colonies worldwide. Infection with this virus, which is often inadvertent and unrecognized, has previously been correlated in numerous anecdotal reports with immune modulation seriously affecting the outcome of biomedical experiments. Studies using experimental models to examine the effects of MHV infection have demonstrated that the virus can both stimulate and depress immune function in vitro. We have used intranasal infection of MHV-susceptible BALB/c mice with MHV strain A59 to examine the effects of this virus on lymphoid tissue composition as well as immune function both in vitro and in vivo. We observed that the thymus, spleen, and lymph nodes underwent a transient period of marked cellular depletion. During that time, the percentages of T and B cells in the spleen remained normal. However, within 1 week after inoculation, splenic lymphoid cell proliferation was significantly decreased in response to the T-cell stimuli, concanavalin A and anti-CD3 monoclonal antibody. This continued through day 35 but was resolved by 102 days postinoculation. Notably, at days 35 and 102, mice infected with MHV-A59 were unable to reject skin grafts at a rate comparable to normal animals. These results support a basis for in vitro and, importantly, long-term in vivo immune dysfunction after infection with MHV.

Metastasizing extra-adrenal paraganglioma with neurological signs in four dogs

Extra-adrenal paragangliomas associated with vertebral pain and clinical neurological abnormalities as a result of metastasis to the vertebral column were diagnosed in four dogs of different breeds by light microscopy. All were males (two intact and two neutered) aged 8 years. Metastatic neoplasms occurred as extradural masses with associated bone lysis at vertebrae C4 (2 cases), T12-L1 (1 case) and L4 (1 case). The neoplastic cells exhibited similar morphology with little variation between cases. All neoplasms showed cytoplasmic granules after staining with the Churukian-Schenk modification of the Pascual argyrophil stain for neurosecretory granules or for membrane bound electron-dense granules (dense-core granules). On immunohistochemical examination the neoplastic cells gave positive results for neuron-specific enolase and negative results for chromogranin and epithelial membrane antigen. Multiple organ metastasis and metastasis to bone have been reported previously, but these cases were unusual due to the involvement of the spine as an apparent predilection site for metastasis, and the sex (male) and age of the animals affected.

Metastasis of a myxoid leiomyosarcoma via the renal and hepatic portal circulation in a sarus crane (Grus antigone)

A 12-year-old female sarus crane (Grus antigone) developed a recurrent proliferative lesion in the subcutaneous tissue of the tarsometatarsus, which failed to respond to medical and surgical therapy. The crane was killed and microscopic examination of the tissues taken at necropsy revealed a myxomatous, poorly-differentiated sarcoma with metastasis to the liver and kidney. Immunohistochemical staining for muscle actin, smooth muscle myosin and vimentin were positive, indicating that the primary and metastatic tumours were leiomyosarcomas. Location of the metastatic lesions in only the portal venous system of the liver and veins of the kidney indicated that the route of metastasis was the portal circulation via the ischiatic vein, caudal mesenteric vein and both the renal-portal shunt and hepatic portal vein. This is the first report of metastatic subcutaneous leiomyosarcoma in an avian species.

Persistent pulmonary interstitial fibrosis, induced by immune response to TNP, is associated with altered mRNA procollagen type I:III ratio

Pulmonary interstitial fibrosis is characterized by a progressive increase in connective tissue in the lung parenchyma. Fibrosis is associated with conditions that result as a consequence of cell mediated responses including graft versus host disease, delayed type hypersensitivity reactions, and granulomas. The hapten-immune animal model for pulmonary interstitial fibrosis correlates the nonresolving fibrosis observed in the lung parenchyma directly with the animal's prior immunization to the hapten. Because the model is patterned after the well studied contact hypersensitivity assay in the skin, the immune response can be directly correlated with a cell-mediated (T-lymphocyte) immune mechanism. Previously, we reported that hapten-immune animals showed increased collagen deposition as identified on routine paraffin fixed slides that were stained with Masson's trichome. In this report, morphometric procedures were used to quantitate the fibrotic lesion. Fibroblasts were harvested from lungs of all treatment groups, cultured, and assayed for collagen production. Once it was determined that collagen production by fibroblasts was similar to that recorded in assays using fresh lung tissue, the fibroblasts were used as a homogeneous cell source for RNA. Total RNA from various treatment groups was used to assess the ratio of mRNA for procollagen I:III using slot and northern blot hybridization procedures. An increased ratio in the procollagen type I:III mRNA was observed in total RNA isolated from fibroblasts from immune and challenged hamsters, and not in samples from all other groups. These results support the hypothesis that the activated T lymphocytes involved in "contact" hypersensitivity-like reactions in the lung regulate not only the quantity, but also the quality of collagen produced by the fibroblasts in the lungs of the hamsters that develop nonresolving fibrosis. The model may be important for the study of skin and pulmonary disease induced by exposure to environmental haptens.

Gastric extramedullary plasmacytoma in a dog

A 10-year-old mixed-breed dog was examined because of a 6-week history of daily vomiting and sporadic diarrhea. On gastroscopy, a crateriform mass was observed on the greater curvature of the stomach. Partial gastrectomy and lymphadenectomy of a large mesenteric lymph node was performed. Gastric plasmacytoma with lymph node metastasis was diagnosed by histologic and immunoperoxidase methods, and chemotherapy was initiated with doxorubicin hydrochloride and diphenhydramine hydrochloride. The dog remains clinically normal 30 months after initial diagnosis. Although gastric plasmacytomas are rare in dogs, long-term survival appears to be better with this disease than with other types of gastric neoplasia.

Laboratory assessment of chronic hepatitis in Syrian hamsters

Clinical chemistry studies in the diagnosis of hamster diseases have received little attention. Although normal values exist for serum constituents, the effects of disease on these values are not well documented. Chronic hepatitis is endemic in several Syrian hamster (Mesocricetus auratus) colonies and is reported mainly through routine histologic examination. We investigated whether any differences in serum clinical chemistries were present in animals with hepatobiliary disease versus unaffected hamsters. Only serum alanine aminotransferase (ALT) and bile acids were significantly elevated in hamsters with chronic hepatitis only. In hamsters that had both chronic hepatitis and biliary disease, the serum ALT, alkaline phosphatase, cholesterol, and bile acids were significantly elevated. The results of this study indicated that serum clinical chemistries may be a useful antemortem diagnostic test for chronic hepatobiliary disease in hamsters.

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.

Identification of immunoglobulin light chains in canine extramedullary plasmacytomas by thioflavine T and immunohistochemistry

Extramedullary plasmacytomas were studied in 29 dogs. The site at which tumors occurred and the age and sex of the dogs were similar to those in previous reports. The skin of the digits, chin, ear, and lip represented the most common (17/29) tumor sites. Males and females were equally represented, and tumors occurred in middle-aged to old dogs (mean age, 9.0 years). A breed predilection was seen in the Cocker Spaniel (n = 7; 24%); Cocker Spaniels represented only 4% (210/4,725) of the submissions during the same period. Tumors were stained with immunohistochemical markers (lambda light chain, K light chain) and thioflavine T. Immunoreactivity was limited to either lambda or K light chains, consistent with a monoclonal plasma cell population. The majority of tumors expressed lambda light chains, consistent with previously reported canine plasma cell dyscrasias. Thioflavine T cytoplasmic fluorescence was seen in the majority (18/29) of plasmacytomas and with inflammatory plasma cells present in control specimens. Other round cell neoplasms (lymphosarcoma, histiocytoma, and mastocytoma) were negative with thioflavine T, indicating that positive staining with thioflavine T was specific for plasma cells (neoplastic and inflammatory). This study confirms by immunohistochemistry that canine extramedullary plasmacytomas disproportionately express lambda light chains and establishes thioflavine T staining as a rapid histochemical method for diagnosis of these tumors.

Development of small-cell osteogenic sarcoma after ulnar ostectomy in a dog

A 5-year-old male Saint Bernard was evaluated for vague forelimb lameness. Four and a half years earlier, the dog had undergone left ulnar ostectomy to correct a valgus deformity. Focal bone lysis was evident radiographically at the ostectomy site. Four months later, marked bony swelling was apparent and the dog was bearing partial weight. The dog was euthanatized, and at necropsy, a bone tumor with lung metastasis was found. Microscopically, features of the tumor were compatible with those of small-cell osteogenic sarcoma.

Dystrophic cardiac calcinosis in mice: abnormal myocardial response to freeze-thaw injury

Dystrophic cardiac calcinosis (DCC) is a frequent finding in DBA/2, C3H and BALB/c mice and its etiology is not known. Previous studies have speculated that myocardial necrosis is involved in the pathogenesis of DCC. In this study, cardiac necrosis was induced in DBA/2, C3H and C57BL/6 mice by freeze-thaw injury through the abdominal diaphragm. Four weeks after freeze-thawing, the mice were sacrificed and the hearts and diaphragms were examined. In response to injury, cardiac mineralization was present only in DBA/2 and C3H mice. The myocardium of C57BL/6 mice (control strain) healed by fibrosis without mineralization, the normal response of the myocardium to injury. Calcified diaphragms also were present at the site of freeze-thaw injury in DBA/2 and C3H mice, which is supportive evidence that a systemic abnormality is involved in the pathogenesis of DCC. The conclusion from this study is that the pathogenesis of DCC in DBA/2 and C3H mice is multifactorial and involves both myocardial necrosis and an abnormal response to injury.

Histopathologic study of herpes virus-induced retinitis in athymic BALB/c mice: evidence for an immunopathogenic process

In order to determine whether antiviral immunity is pathogenic in mouse eyes, HSV-1 was injected into the anterior chamber of one eye of adult athymic BALB/c mice. The eyes of these T cell deficient mice were examined clinically and histopathologically for ocular disease. The anterior segment of injected eyes developed progressive inflammatory reactions that eventually destroyed the ciliary body and then progressed to the posterior compartment where partial necrosis occurred, but only in the inner layers of the retina. A milder form of the same process developed between 7 and 10 days in the contralateral eye. Uninoculated eyes displayed little evidence of choroiditis, hemorrhage, massive necrosis, or disintegration of the architecture of the retina. Since these are features that are found in contralateral retinas of euthymic BALB/c mice infected in one eye via the anterior chamber route, it is concluded that acute retinitis found in contralateral eyes of immunocompetent mice has an immunopathogenic basis. However since euthymic mice develop anterior chamber associated immune deviation (ACAID) (and therefore do not display virus-specific delayed hypersensitivity), the identity of the relevant immune effector remains unknown. Based on these observations and our previous ocular findings following intracameral inoculation of HSV-2, we suggest that in susceptible mice, herpes simplex viruses can induce several pathogenetically distinct forms of retinitis, some of which are mediated by virus-specific immune effector cells.

Feline immunodeficiency virus infection in a population of pet cats from southeastern Florida

Blood samples from 95 randomly selected pet cats that were brought to veterinarians in southeastern Florida were tested for antibodies to feline immunodeficiency virus (FIV). Virus-specific antibodies (indicative of virus infection) were found in 8 of the 95 (8.4%) cats tested. All of the virus-infected cats were males (statistically significant, P less than or equal to 0.016) and were at least 1 year of age. The 3 most severely ill cats infected with FIV were also infected with feline leukemia virus.

Schisis contributes to necrosis in experimental HSV-1 retinitis

Injection of the KOS strain of herpes simplex virus type 1 into the anterior chamber of one eye of a BALB/c mouse produces bilateral retinal inflammation which progresses in the contralateral eye to total retinal necrosis by day 10 post-inoculation. Although both immune and direct viral cytopathic effects have been proposed as causes of the initial infiltration, the precise mechanism(s) of the contralateral retinal necrosis remains uncertain. In this study, histopathological examination of the uninoculated eyes of HSV-1 injected BALB/c mice revealed the presence of vitreous traction against the internal limiting membrane of the retina which was associated with separation of the nerve fiber layer from the underlying ganglion cell layer. This separation resulted in avulsion of Mueller cell footplates and retinal vessels, hemorrhage into the schisis cavity and disruption of the underlying retinal architecture. The schisis began focally on day 8 or 9 post-inoculation, and the entire retina of most animals was involved by day 10 or 11. These results suggest that retinal schisis involving separation of the nerve fiber layer from the ganglion cell layer contributes to necrosis of the retina in the uninoculated contralateral eye.

Neoplasia in ferrets: eleven cases with a review

Records from a veterinary diagnostic laboratory in south Florida, U.S.A. were reviewed for cases of neoplasia in pet ferrets. Twelve ferret tumours were received over a four-year period; one case, a ferret with lymphocytic leukaemia and multi-organ involvement, had been reported previously. The other eleven tumours were: two chordomas of the tail, two sebaceous adenomas of the skin, a sebaceous epithelioma of the skin, a cutaneous mastocytoma, a malignant fibrous histiocytoma from the eyelid, a malignant mesenchymoma and an undifferentiated sarcoma from the dorsal abdominal cavity, a leiomyosarcoma found unattached in the abdominal cavity and an interstitial cell tumour of the testicle. A review of the literature yielded reports of 83 other tumours in domestic ferrets, black-footed ferrets and European polecats. Of the 95 ferret tumours, 46 were considered malignant. Tumours occurred in all organ systems except the respiratory tract and central nervous system. Affected ferrets ranged in age from 209 days to 12 years. The most frequently occurring tumours were ovarian stromal tumours (24 of 95), haemangiomas/haemangio-sarcomas (15 of 95). This information indicates that, contrary to previous opinion, ferrets appear to be subject to a similar incidence and variety of tumours as other animals.

Hepatic protection from chemical injury by isoflurane

Isoflurane inhibits oxidative metabolism of halothane. Because hepatotoxicity of chemicals may be associated with their metabolism, whether isoflurane can protect the liver against chemical injury was investigated. Hepatic injury was produced in female F344 rats by a 30-minute exposure to 250 ppm of carbon tetrachloride. In this and all other parts of the study, the inspired oxygen concentration was maintained at 21%. The injury was accompanied by elevated activity of liver enzymes in serum (SGOT, SGPT, and SDH), enlarged liver, fatty infiltration of the liver, and vacuolar degeneration of hepatocytes. These signs of toxicity were partly or completely suppressed by concurrent exposure to subanesthetic concentrations of isoflurane (0.2 or 0.038%, respectively). The protective effect was concentration-dependent. Enflurane was protective, but less so than isoflurane. Nitrous oxide and fentanyl had no protective effect.

Protothecosis in two cats

Protothecosis was diagnosed in 2 cats from Florida with nodular skin lesions. Microscopically, lesions were composed of macrophages and multinucleated giant cells arranged in solid sheets in the dermis and subcutis. In both cats, characteristic algal endospores identified as Prototheca wickerhamii were observed within the cytoplasm of infiltrating cells.

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.

Focal mucinosis in dogs: seven cases and review of cutaneous mucinoses of man and animals

Seven dogs had one or more asymptomatic nodules, papules, or plaques on the skin or oral mucosa. The primary histologic feature was the accumulation of excess mucin within the dermis or submucosa. Based upon the clinical presentation and the histopathologic changes, it was proposed that these lesions represent the canine analogue of focal mucinosis in man, and that the same name be applied to the lesion in dogs. The criteria for the diagnosis of focal mucinosis were: (1) the presence of a single (rarely multiple) papule, nodule, or plaque which may be firm, rubbery, or soft, (2) the accumulation of mucin which disrupts and separates collagen fibers, (3) mild to extensive fibroblast proliferation, and (4) a mild mononuclear cell infiltration. The mucinoses of man and animals were reviewed.

Topical fluorouracil. II. Postoperative administration in an animal model of glaucoma filtering surgery

Unilateral posterior lip sclerectomies were performed in ten owl monkeys. Five milligrams of fluorouracil was injected subconjunctivally in each operated eye immediately after surgery. Three drops (approximately 2.4 mg/drop) of fluorouracil were instilled ten minutes apart in each operated eye twice daily on postoperative days 1 through 7 and once daily on postoperative days 8 through 15, 17, 19, and 21. One monkey died on the seventh postoperative day; its death could not be attributed to systemic fluorouracil toxicity. All of the operated eyes had filtering blebs after the full course of fluorouracil, but seven also had corneal epithelial defects. By the seventh postoperative week, two of the operated eyes manifested moderately severe corneal opacification. Ten weeks postoperatively, the electroretinographic a- and b-wave amplitudes averaged 17% and 12% less, respectively, in the seven operated eyes without clinically significant corneal opacification than in the unoperated fellow eyes. Only two eyes had blebs after the 12th postoperative week. Histopathologic examination was performed on five eyes, of which only two revealed patent sclerostomies. Although topical fluorouracil appears to delay bleb scarring, the corneal findings suggest that it may be more toxic than subconjunctival fluorouracil.

Cardiomyopathy in stranded pygmy and dwarf sperm whales

Necropsy and histologic examinations were performed in 23 pygmy sperm whales (Kogia breviceps) and 6 dwarf sperm whales (Kogia simus) that had been stranded singly or in cow-calf pairs along the southeastern coastline of the United States. At necropsy, the gross findings in the adult whales included pale, flabby right ventricles. Microscopically, lesions in the hearts of the whales were characterized by moderate to extensive myocellular degeneration, atrophy, and fibrosis. Similar changes were not seen in 5 of 6 sexually immature whales or in the whale calves. Hepatic changes were consistent with heart failure. The cause of the myocardial lesions was not determined. The systemic effects of failing myocardium probably were a major reason for the stranding of the adult whales.

The effect of methionine on the progression of hepatocellular carcinoma induced by ethionine

Female Wistar rats were fed a semisynthetic diet containing 0.3% DL-ethionine for 52 weeks and, most of them bearing hepatocellular carcinomas, were switched to a basal diet for one week and then received 80 mg DL-methionine per rat (cir. 25 mg/100 g body wt) by gavage once per day, five times a week, over a period of 13 weeks. Methionine treatment significantly affected progression of hepatic tumors induced by DL-ethionine administration. The frequency of rats with hepatocellular carcinomas in the methionine treated group was significantly lower than that in control groups. It therefore appears that methionine treatment resulted in a remission of the malignant process.

Failure of pure 1-naphthylamine to induce bladder tumors in dogs

1-Naphthylamine was administered p.o. to beagles for approximately 9 years at a daily dose of 15 mg/kg (5 days a week). At autopsy, no tumors or other pathological changes were observed in the bladders of any of these animals. With the possible exception of the excessive accumulation of lipofuscin in the hepatocytes of these dogs, no test compound-related pathological changes in other tissues of the body were observed. Analysis of the urine revealed the presence of small amounts of N-oxidation products (1-nitrosonaphthalene plus N-hydroxy-1-naphthylamine), ranging from 2.85 to 125 microgram, following a dose of 1-naphthylamine. The theoretical significance of these findings is discussed.

A spontaneous outbreak of polychlorinated biphenyl (PCB) toxicity in rhesus monkeys (Macaca mulatta): clinical observations

A spontaneous, progressive disease occurred in a large domestic breeding colony of rhesus monkeys (Macaca mulatta). The disease was characterized by slow but continuous weight loss, alopecia, acne, facial edema, diarrhea and trauma from other monkeys. Breeding efficiency was impaired with a high incidence of abortions and stillbirths. Live offspring were small and unthrifty contributing to a high infant mortality rate. The cause of this disease was polychlorinated biphenyls (PCSs) which were present in the concrete sealant on the cage floors. Removing the sealant and resurfacing the floors alleviated the problem.