CD8-positive lymphocytes in graft-versus-host disease of humanized NOD.Cg-Prkdc(scid)Il2rg(tm1Wjl)/SzJ mice.

Immunocompromised mice that can support a human immune system are an increasingly important model for the investigation of haemopoietic stem/progenitor cell (HSPC) development and human infectious disease. NOD-SCID IL-2Rγ(-/-) (NSG) mice engrafted with human fetal liver and thymus prior to HSPC engraftment, commonly known as NSG-bone marrow-liver-thymus (NSG-hu-BLT) mice, are one such model and have robust reconstitution of human leucocytes within the peripheral blood and tissues. Four NSG-hu-BLT mice were submitted for diagnostic necropsy examination following the development of alopecia, pruritus and lethargy after HSPC engraftment. Histopathology revealed multifocal to coalescing single keratinocyte cell death in the epidermis and follicles with dermatitis and mild dermal fibrosis. Single-cell hepatocyte cell death was present in three cases, with various degrees of portal fibrosis. In the skin and liver, cell death was associated with lymphocytes that reacted with anti-human CD45, CD3 and CD8 antibodies, consistent with a diagnosis of graft-versus-host disease (GvHD). This study expands on recently reported microscopical features of GvHD in NSG-hu-BLT mice and suggests a role for CD8(+) T lymphocytes in the progression of the disease. NSG-hu-BLT mice represent an excellent model of GvHD, but its prevalence may compromise their use in other fields of biomedical research.

Opportunistic bacterial infections in breeding colonies of the NSG mouse strain.

Spontaneous morbidity primarily affecting female breeders in 3 independent breeding colonies of NSG (NOD.Cg-Prkdc(scid) I12rg(tm1Wjl) /SzJ) mice prompted an investigation to uncover the cause of disease. Necropsies were performed on 264 (157 female and 107 male) spontaneously sick, experimentally unmanipulated NSG mice. In sum, 42 mice (15.9%) had acute or chronic renal inflammatory lesions, of which 12 had concurrent histologic evidence of an ascending urinary tract infection. From 94 kidneys cultured for bacterial organisms, 23 (24.5%) grew Enterococcus sp and 19 (20.2%) grew Klebsiella oxytoca. Female mice were twice more likely than males to present with nephritis. These findings indicate that bacterial nephritis is a major contributor to morbidity in the NSG strain.

Cyclin D3 expression in normal fetal, normal adult and neoplastic feline tissue.

Cyclin D3 is a tightly regulated cell cycle protein and member of the cyclin D family-a group of proteins that facilitates the progression of a cell through G(1) and into the S phase of the cell cycle. All cells use at least one of the cyclin D proteins for cell cycle regulation. In this study, feline tissues (normal fetal and adult, and neoplastic) were examined immunohistochemically for expression and topographical distribution of cyclin D3. Its distribution was similar to that in human tissues in health and neoplasia, and suggested a dual role of cyclin D3 in cell proliferation and differentiation. Immature lymphoid tissue and proliferating epithelial cells in health and neoplasia were immunoreactive for cyclin D3, whereas expression of the protein in other immunoreactive tissues reflected differentiated cell types. Immunoreactivity for cyclin D3 was particularly striking in germinal centre cells of normal lymph nodes and B-cell lymphomas, and in normal suprabasal epithelial cells of the skin and mucous membranes of the oropharynx and in squamous cell carcinomas at these sites.

Histopathologic findings and classification of feline renal transplants.

Seventy-seven feline transplant kidney specimens, obtained from 1 to 3,183 days (9 years) after transplantation, were reevaluated histologically and classified on the basis of the Banff '97 guidelines for human renal transplant kidneys. Overall, this classification system appeared useful in detecting rejection reactions and confirmed the finding in humans that biopsies can diagnose subclinical rejection and therefore are an important diagnostic tool for the follow up of renal transplants. However, on the basis of serum creatinine values, the severity of the acute or active and chronic lesions was not accurately reflected by this scoring system. This is thought to be due to the significant differences in histologic rejection patterns, especially in acute or active rejection, in cats when compared with humans. Tubulitis, lymphocytic glomerulitis, and vasculitis, which are the main pillars of the Banff '97 acute or active rejection scoring system, are either rare or not found in cats. The presence of significant necrotizing glomerulitis and vasculitis in feline renal transplants might imply that the rejection is complicated by acute antibody-mediated rejection. Alternatively, cyclosporine toxicity also should be considered because some of these kidneys show other signs of cyclosporine toxicity. Finally, the significance of subcapsular and interlobular phlebitis, rarely described in human rejection reactions but a distinct entity in cats, is unknown. From this study, it is clear that there are significant differences in the histology of acute or active rejection between humans and cats and that a better understanding of the histologic appearance of renal allografts will be especially beneficial for treatment and prognostic purposes.

T-cell-derived malignant lymphoma in the boxer breed.

The boxer breed of dog is at high risk for a variety of neoplasms including lymphoma. In this observational study, tissue sections from boxer dogs with lymphoma were immunostained for T and B lymphocyte distinction, and the results compared with similar studies carried out on lymphoma tissues from temporally selected cohorts of golden retriever and rottweiler dogs. The frequency of T-cell lymphomas was significantly (P < 0.001 for all comparisons) higher in the boxers than in the rottweilers or golden retrievers. We are unaware of other reports linking immunotype of canine lymphoma with breed; whether other brachycephalic breeds of dogs have a similar preponderance of T-cell lymphoma awaits further study.

Feline vaccine-associated fibrosarcoma: morphologic distinctions.

Forty-four primary feline vaccine-associated fibrosarcomas and 16 recurrences were examined histologically for detailed morphologic characterization with emphasis on tumor grade, presence of neoplastic multinucleated giant cells, presence and proportion of T and B lymphocytes within the tumor, and thin and intermediate filament contents of neoplastic and stromal cells. The microvascularity and proliferation rates of central and peripheral areas of the tumors were also quantified by computerized image analysis. For primary fibrosarcomas, 11 of 44 (25%) were grade I, 21 of 44 (47.7%) were grade II, and 12 of 44 (27.3%) were grade III. The recurrences followed a similar pattern: 4 of 16 (25%) were grade I, 8 of 16 (50%) were grade II, and 4 of 16 (25%) were grade III. A positive correlation was found between the presence of neoplastic multinucleated giant cells and tumor grade. These cells were present in 9 of 12 (75%) of grade III and none of the grade I tumors. Prominent peritumoral lymphoid aggregates or follicles were present in 59% of the tumors, and many contained high proportions of T lymphocytes, varying from 19 to 87%. All fibrosarcomas were immunoreactive for vimentin and 28 of 44 (64%) were reactive for alpha-smooth muscle actin. The actin-positive cells were either part of the tumor or formed a capsule around tumor nodules. The peripheral vascularity was significantly higher than the central vascular density but no difference was found in tumor cell proliferation rates between the two areas. Centrally located, fluid-filled micro- or macrocavitations were frequently observed in the large vaccine sarcomas and probably formed secondary to rapid tumor growth and central necrosis.

Fluvastatin in combination with rad significantly reduces graft vascular disease in rat cardiac allografts.

BACKGROUND: RAD is a potent immunosuppressive agent that has been shown to be effective in preventing acute and chronic allograft rejection in animal models. The HMGCoA reductase inhibitors have been found to reduce the incidence of graft vascular disease (GVD) in heart transplant patients and in animal models. This study was designed to investigate the effects of fluvastatin or pravastatin in a rodent model of GVD produced using low doses of RAD to prevent acute rejection. METHODS: Hearts from Fisher 344 rats were heterotopically transplanted to Lewis rat recipients. RAD was administered orally at 0.5 mg/kg per day for days 0 to 14 and then 0.25 mg/kg per day for an additional 85 days to prevent acute rejection but allow for the development of GVD. Pravastatin (20 mg/kg per day) or fluvastatin (2 or 6 mg/kg per day) was added to the RAD treatment. At the end of a 100-day treatment period, the hearts were harvested for morphometric and histopathologic examinations. RESULTS: Rats treated with fluvastatin, at either dose, had a significant (P< or =0.0239) decrease in coronary arterial intimal thickening (GVD) of approximately 43%. Rats treated with pravastatin had a 22% reduction in GVD that did not reach statistical significance. Treatment with fluvastatin, but not pravastatin, decreased the degree of endomyocardial mononuclear cell infiltration seen with RAD administered alone. CONCLUSIONS: Fluvastatin significantly decreased GVD in a rat model produced using low-dose RAD immunosuppression. To a lesser extent, pravastatin also decreased GVD in this model. These data lend further support for the study of fluvastatin, pravastatin, and other HMG-CoA reductase inhibitors for the prevention of GVD in cardiac transplant patients.

Effects of haemoglobin-based oxygen carrier hemoglobin glutamer-200 (bovine) on intestinal perfusion and oxygenation in a canine hypovolaemia model.

The objective of this investigation was to study the effects of the first marketed haemoglobin-based oxygen carrier, Hemoglobin glutamer-200 (bovine) (Hb-200) (Oxyglobin) on splanchnic perfusion and oxygenation in a canine model of acute hypovolaemia. Twelve anaesthetized dogs [mean weight 30.8 (S.D. 1.4) kg] were instrumented for recordings of heart rate (HR), mean arterial pressure (MAP), central venous pressure (CVP), cardiac output and cranial mesenteric arterial (CMA) and venous blood flows (CMV). Total and plasma haemoglobin (Hb), oxygen content and saturation, lactate concentration, pH and blood gases were analysed in arterial, mixed venous and mesenteric venous blood samples. Measurements were made before (baseline) and after 1 h of haemorrhage, after which animals were resuscitated with either shed blood (controls) or Hb-200 until HR, MAP and CVP returned to prehaemorrhage levels. Recordings were repeated immediately and 3 h after termination of fluid resuscitation, after which organ specimens were obtained for microscopic examination. Haemorrhage (average 32 ml kg(-1)) reduced MAP to 50 mm Hg, increased HR and systemic vascular resistance (SVR), and was accompanied in both the systemic and the splanchnic circulation by significant decreases in blood flow, Hb content and oxygen delivery (DO2), and lactic acidosis. In controls, all variables recovered to baseline after isovolaemic resuscitation with shed blood. In dogs resuscitated with a small volume of Hb-200 (10 ml kg(-1)), HR, MAP, CVP and CMA and CMV blood flows returned to baseline. However, cardiac output, total Hb, oxygen content and systemic and mesenteric DO2 remained depressed while SVR increased further. Mesenteric and systemic acid-base status recovered in both groups, and there was no difference in microscopic tissue damage between groups. Thus, Hb-200 reconstituted splanchnic perfusion and oxidative metabolism in spite of pronounced systemic vasoconstriction and insufficient restoration of CO and DO2; it may improve diffusive oxygen transport in the microvasculature by virtue of haemodilution and its high efficiency in the uptake and release of oxygen.

Comparison of practical treatment methods to eradicate pinworm (Dentostomella translucida) infections from Mongolian gerbils (Meroines unguiculatus).

This study evaluates the efficacy of various treatment methods to eradicate Dentostomella translucida from Mongolian gerbil colonies. The following five treatment methods were instituted in naturally infected groups of 10 gerbils each: topical ivermectin misting, ivermectin-medicated drinking water, piperazine citrate-medicated drinking water, fenbendazole-medicated feed, and a combination of ivermectin-medicated drinking water and fenbendazole-medicated feed. Treatment success was assessed by using weekly fecal flotations, with necropsy examinations performed on fecal-negative gerbils (except those in the misted group) at 5 weeks after the last treatment. Topical ivermectin misting left 40% of gerbils fecal-positive. With piperazine citrate-medicated drinking water, 60% of the gerbils were fecal-positive; the remaining 40% had adult worms in their digestive tract at necropsy. Ivermectin-medicated drinking water caused 80% of the gerbils to be negative on fecal flotation. On necropsy, however, all but one of these gerbils harbored adult pinworms. Treatments with fenbendazole-supplemented feed alone or in combination with ivermectin-treated water resulted in no fecal shedding or evidence of adult pinworms on necropsy examination. Of the five treatments evaluated, only those using fenbendazole-medicated feed (150 ppm) provided a practical and reliable treatment method to eradicate pinworm infections in Mongolian gerbil colonies.

Comparison of results of thoracic radiography, cytologic evaluation of bronchoalveolar lavage fluid, and histologic evaluation of lung specimens in dogs with respiratory tract disease: 16 cases (1996-2000).

OBJECTIVE: To compare results of thoracic radiography, cytologic evaluation of bronchoalveolar lavage (BAL) fluid, and histologic evaluation of biopsy and necropsy specimens in dogs with respiratory tract disease and to determine whether histologic evaluation provides important diagnostic information not attainable by the other methods. DESIGN: Retrospective study. ANIMALS: 16 dogs. PROCEDURE: BAL fluid was classified as normal, neutrophilic, eosinophilic, mononuclear, mixed, neoplastic, or nondiagnostic. Radiographic abnormalities were classified as interstitial, bronchial, bronchointerstitial, or alveolar. Histologic lesions were classified as inflammatory, fibrotic, or neoplastic, and the predominant site of histologic lesions was classified as the alveoli, interstitium, or airway. RESULTS: The predominant radiographic location of lesions correlated with the histologic location in 8 dogs. Of 11 dogs with histologic evidence of inflammatory disease, 8 had inflammatory BAL fluid. Of the 2 dogs with histologic evidence of neoplasia, 1 had BAL fluid suggestive of neoplasia, and the other had BAL fluid consistent with septic purulent inflammation. Two dogs without any histologic abnormalities had mononuclear or nondiagnostic BAL fluid. Two dogs with histologic evidence of fibrosis had mononuclear or mixed inflammatory BAL fluid. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that although thoracic radiography, cytologic evaluation of BAL fluid, and histologic evaluation of lung specimens are complementary, each method has limitations in regard to how well results reflect the underlying disease process in dogs with respiratory tract disease. Lung biopsy should be considered in cases where results of radiography and cytology are nondiagnostic.

Bovine papillomavirus DNA in neoplastic and nonneoplastic tissues obtained from horses with and without sarcoids in the western United States.

OBJECTIVE: To determine the incidence of bovine papillomavirus (BPV) type 1 or 2 in sarcoids and other samples of cutaneous tissues collected from horses in the western United States. ANIMALS: 55 horses with sarcoids and 12 horses without sarcoids. PROCEDURE: Tissue samples (tumor and normal skin from horses with sarcoids and normal skin, papillomas, and nonsarcoid cutaneous neoplasms from horses without sarcoids) were collected. Tissue samples were analyzed for BPV-1 or -2 DNA, using a polymerase chain reaction (PCR) and restriction fragment length polymorphism. The PCR products from 7 sarcoid-affected horses were sequenced to evaluate percentage homology with expected sequences for BPV-1 or-2. RESULTS: Most (94/96, 98%) sarcoids contained BPV DNA. Sixty-two percent of the tumors examined had restriction enzyme patterns consistent with BPV-2. Thirty-one of 49 (63%) samples of normal skin obtained from horses with sarcoids contained BPV DNA. All samples subsequently sequenced had 100% homology with the expected sequences for the specific viral type. All tissues from healthy horses, nonsarcoid neoplasms, and papillomas were negative for BPV DNA. CONCLUSIONS AND CLINICAL RELEVANCE: Bovine papillomaviral DNA was detected in essentially all sarcoids examined. There appears to be regional variation in the prevalence of viral types in these tumors. The fact that we detected viral DNA in normal skin samples from horses with sarcoids suggests the possibility of a latent viral phase. Viral latency may be 1 explanation for the high rate of recurrence following surgical excision of sarcoids.

Feline vaccine-associated fibrosarcoma: an ultrastructural study of 20 tumors (1996-1999).

Twenty feline vaccine-associated sarcomas were examined by transmission electron microscopy. Tumors contained pleomorphic spindle cells, histiocytoid cells, and giant cells. Most tumors contained myofibroblasts, which had morphologic features similar to those of fibroblasts. These cells were further distinguished by subplasmalemmal dense plaques and thin cytoplasmic actin myofilaments organized as elongated bundles concentrated at irregular intervals forming characteristic dense bodies. Intracellular crystalline particulate material was found in 5 of the 20 tumors. Energy dispersive X-ray spectroscopy was used to identify the crystalline material within one tumor as aluminum-based. One tumor from a feline leukemia virus-infected cat contained budding and immature retroviral particles.

Bax/bcl-2: cellular modulator of apoptosis in feline skin and basal cell tumours.

Bcl-2 and bax are two members of the BCL-2 gene family that play a prominent role in the regulation of apoptosis. Bax and bcl-2 expression were examined immunohistochemically in normal (healthy) feline skin and in 24 benign feline cutaneous basal cell tumours. The tumours were also examined for cellular proliferation by measurement of reactivity for the proliferation marker Ki-67, and for apoptosis by in-situ labelling for fragmented DNA. Bcl-2 was detected in normal basal epithelium and in 23 of 24 basal cell tumours. Bax was detected in both basal and suprabasal epithelium, but in only seven of 24 tumours. For tumours that expressed both bax and bcl-2, the bax:bcl-2 ratio was low. Neither bax nor bcl-2 expression was detected in 14 feline cutaneous squamous cell carcinomas. Basal cell tumours showed modest cellular proliferation (median, 17.5% Ki-67- reactive cells), but few (less than 1%) apoptotic cells. The slow, indolent growth of feline cutaneous basal cells in these benign skin tumours may be a response, at least in part, to opposing regulatory expressions of bcl-2 and bax.

Spontaneous intestinal adenocarcinoma in geriatric macaques (Macaca sp.).

BACKGROUND AND PURPOSE: Intestinal adenocarcinoma appears to be the most common malignant neoplasm in macaques, and is a substantial cause of morbidity and mortality in the elderly. METHODS: A retrospective review of 32 cases was done. RESULTS: Thirty-two cases were reviewed. Clinical examination had revealed severe weight loss, anorexia, and palpable abdominal mass. Microcytic hypochromic anemia, intermittent fecal occult blood positive test results, hypoproteinemia, and hypoalbuminemia were the predominant clinical laboratory findings. Carcinoembryogenic antigen serologic testing and single-strand conformational polymorphism analysis were performed in selected cases. The most common sites of the intestinal adenocarcinoma were ileocecal junction, colon, ileum, jejunum, and cecum. Metastases were evident in 34% of the cases and involved peripheral nodes, liver, lungs, pancreas, and adrenal gland. Overall survival of 12 macaques that underwent surgical excision was 83% at 6 months, 58% at 1 year, 50% at 1.5 years, 33% at 2 years, and 8% at 4 years. The overall mean survival rate (MSR) was > 483 postoperative days. CONCLUSION: Intestinal adenocarcinomas should be amenable to surgical resection. Early detection of localized, non-invasive neoplasms will increase surgical cure rate. Survivability could be potentially improved by use of adjuvant therapies.

Histopathological, radiographic, and arthrographic comparison of the biceps tendon in normal dogs and dogs with biceps tenosynovitis.

In dogs surgically treated for biceps tenosynovitis, the most common histopathological findings were fibrosis and collagen degeneration (n=13), synovial villous or vascular hyperplasia (n=10), lymphocytic-plasmacytic infiltrates (n=10), cartilaginous metaplasia (n=8), and ischemic necrosis (n=5). Degree of histopathological changes was associated with degree (p equals 0.000), but not duration (p equals 0.543), of lameness. Furthermore, there was no association between histopathological changes and age or radiographic and arthrographic findings. Cartilage metaplasia was the only histopathological finding in both affected tendons (8/18) and normal control dogs (13/13). Age and size of the control dogs were not determined; however, since all these dogs were clinically normal, fibrocartilaginous metaplasia can be present as an incidental finding in the biceps tendon of origin in dogs.

Radio-frequency electrocautery ablation of mammary tissue in swine.

PURPOSE: To establish the size, configuration, and histopathologic features of acute, subacute, and chronic radio-frequency (RF) electrocautery of mammary tissue in swine. MATERIALS AND METHODS: Eighteen RF treatments were performed in the mammary tissue of three domestic swine under ultrasonographic (US) guidance. Histopathologic examination was performed immediately after (acute animal); 2 weeks after (subacute animal); and 4 weeks after (chronic animal) treatment. RESULTS: In the acute animal, lesions were firm nodules on palpation and had a distinct line of demarcation between necrotic and viable mammary tissue (mean lesion volume, 14.24 cm(3); largest volume, 29.06 cm(3)). In the subacute animal, there was diffuse coagulation necrosis with neutrophilic infiltrates at the periphery (mean lesion volume, 6.46 cm(3); largest volume, 9.47 cm(3)), and two treatment areas had a secondary bacterial infection. In the chronic animal, lesions were still palpable and firm (mean lesion volume, 11.67 cm(3); largest volume, 25.5 cm(3)), and five of six treatment sites had an area of gray to white fibrotic tissue that blended with the surrounding tissue. However, one site had a pale yellow area of central necrosis surrounded by a fibrotic area. In both the subacute and chronic animals, two and one treatment site, respectively, had minimal areas of skin necrosis. CONCLUSION: RF ablation of breast tissue is feasible in this animal model. Problems included minimal skin erythema, residual firm treatment regions at 4 weeks, slightly variable margins of coagulation necrosis, and occasional bacterial infection.

Differential regulation of c-jun expression in liver and lung of mice after thermal injury.

In addition to skin injury, burns may also damage distant organs. Understanding the mechanisms of distant organ injury will substantially improve the survival of burn patients. Transcription factors are the major regulators of gene expression in response to most types of injury. C-Jun, which is a part of the activator protein-1 transcription factor complex, is one of the major immediate-early response genes, which is rapidly induced after injury. The expression of c-Jun in mouse liver and lung at different time points (3 h to 29 days) after thermal injury was examined by using Reverse Transcription-Polymerase Chain Reaction (RT-PCR), Western blot, and immunohistochemistry. Rapid induction of c-Jun mRNA and protein was observed in the liver 3 h after an 18% TBSA burn. C-Jun expression returned to basal levels within 3 days after injury. In contrast to the up-regulation observed in liver, lungs from the same mice expressed c-Jun constitutively throughout the same time points. The finding that thermal injury leads to up-regulation of c-Jun in liver but not lungs suggests that either the liver has a lower threshold for early response to injury or that different cellular events exist when each organ is stressed.