In vivo safety, biodistribution and antitumor effects of uPAR retargeted oncolytic measles virus in syngeneic cancer models.

The urokinase receptor (uPAR) is a clinically relevant target for novel biological therapies. We have previously rescued oncolytic measles viruses fully retargeted against human (MV-h-uPA) or murine (MV-m-uPA) uPAR. Here, we investigated the in vivo effects of systemic administration of MV-m-uPA in immunocompetent cancer models. MV-m-uPA induced in vitro cytotoxicity and replicated in a receptor-dependent manner in murine mammary (4T1) and colon (MC-38 and CT-26) cancer cells. Intravenous administration of MV-m-uPA to 4T1 tumor-bearing mice was not associated with significant clinical or laboratory toxicity. Higher MV-N RNA copy numbers were detected in primary tumors, and viable viral particles were recovered from tumor-bearing tissues only. Non-tumor-bearing organs did not show histological signs of viral-induced toxicity. Serum anti-MV antibodies were detected at day 14 of treatment. Immunohistochemistry and immunofluorescence studies confirmed successful tumor targeting and demonstrated enhanced MV-m-uPA-induced tumor cell apoptosis in treated compared with control mice. Significant antitumor effects and prolonged survival were observed after systemic administration of MV-m-uPA in colon (CT-26) and mammary (4T1) cancer models. The above results show safety and feasibility of uPAR targeting by an oncolytic virus, and confirm significant antitumor effects in highly aggressive syngeneic immunocompetent cancer models.

Circulating levels of glucocorticoid hormones in WHHL and NZW rabbits: circadian cycle and response to repeated social encounter.

Social environment influences the progression of atherosclerosis in an important experimental model of disease, the Watanabe Heritable Hyperlipidemic rabbit (WHHL). Although the hypothalamic-pituitary-adrenocortical (HPA) system is likely to play an important role in the behavioral modulation of disease, relatively little is known about the glucocorticoid responses in these animals, or in other strains of rabbits. The purpose of the present study was to: (1) evaluate the rabbit glucocorticoid circadian rhythm, (2) compare plasma cortisol and corticosterone responses to social stress, and (3) examine strain differences (i.e., WHHL vs. New Zealand White (NZW)) in rabbit glucocorticoid responses to assess whether WHHLs have an aberrant HPA system. It was found that male rabbits secrete both corticosterone and cortisol in a circadian rhythm that peaks in the afternoon and reaches a nadir at 0600 h, i.e., approximately 12 h out-of-phase with the human glucocorticoid rhythm. Both glucocorticoids responded similarly to social stress induced by repeated daily 4 h pairings with another male rabbit; after 10 days of pairings, glucorticoid values were significantly correlated with the amount of defensive agonistic behavior exhibited. Finally, there were no significant strain differences in glucocorticoid circadian rhythms, baselines, or responses to social stress. These data suggest that glucocorticoid responses (i.e., circadian rhythms, responses to social stress) in the WHHL are similar to glucocorticoid responses in standard laboratory white rabbits.

Florida Red Tide: Inhalation Toxicity of Karenia brevis Extract in Rats.

Brevetoxins are neurotoxins produced by the marine dinoflagellate Karenia brevis. Histopathologic examination of marine mammals dying following repeated exposure of brevetoxins during red tide events suggests that the respiratory tract, nervous, hematopoietic, and immune systems are potential targets for toxicity in repeatedly exposed individuals. The purpose of this experiment was to evaluate the effects of repeated inhalation of K. brevis extract on these potential target systems in rats. Male Sprague-Dawley rats were exposed four hours/day, five days/week for up to four weeks to target concentrations of 200 and 1000 µg/L K. brevis extract (approximately 50 and 200 µg/L brevetoxin-like compounds; positive neurotoxicity in a fish bioassay). Control rats were sham exposed to air. Immunohistochemical staining of pulmonary macrophages indicated deposition of brevetoxin-like compound within the lung. However, exposure resulted in no clinical signs of toxicity or behavioral changes. There were no adverse effects on hematology or serum chemistry. No histopathological changes were observed in the nose, lung, liver, kidneys, lymph nodes, spleen, or brain of exposed rats. Immune suppression was suggested by reduced responses of spleen cells in the IgM-specific antibody-forming plaque cell response assay and reduced responses of lymphocytes to mitogen stimulation in vitro. Differences between responses observed in rats in this study and those observed in manatees may be a function of dose or species differences in sensitivity.

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.

Cholangiocarcinoma with metastasis in a captive Adelie penguin (Pygoscelis adeliae).

A captive male Adelie penguin (Pygoscelis adeliae), wild caught in 1976, died unexpectedly. Necropsy revealed cholangiocarcinoma with metastases to lung, pancreas, mesentery, and cloaca, the first known case of a penguin hepatic tumor.

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.

Radiofrequency ablation of rabbit kidney using liquid electrode: acute and chronic observations.

BACKGROUND AND PURPOSE: The percentage of small renal tumors being diagnosed has increased at least five-fold in the last 20 years. The question of how best to treat these lesions remains unanswered. We studied the effectiveness of "wet" radiofrequency (RF) ablation of renal tissue. MATERIALS AND METHODS: New Zealand white rabbits (N = 48) underwent a 1- or 2-minute ablation of renal parenchyma with a modified insulated spinal needle capable of infusing saline, measuring temperature and impedance, and delivering RF energy. Animals were followed and examined up to 54 days after surgery. RESULTS: All animals survived for the planned period. Intravenous urograms showed no fistula or urinoma formation and confirmed continued function of the remaining parenchyma. The 1-minute treatments consistently ablated 20% to 25% (average 7 cm) of the tissue, whereas the 2-minute treatments ablated 34% to 36% (average 10 cm). Acutely, there was coagulative necrosis and infiltration of inflammatory cells. Chronically, there were well-demarcated lesions with complete effacement of the tubular epithelium and destruction of the glomeruli. CONCLUSION: Wet radiofrequency ablation with a liquid electrode can reproducibly create large lesions safely and quickly. The technique may soon become an alternative, minimally invasive therapy for small renal tumors.

Protein electrophoresis as a diagnostic and prognostic tool in raptor medicine.

Plasma proteins of 139 healthy adult birds of prey from 10 species were separated by electrophoresis to characterize and document normal reference ranges and species-specific electrophoretic patternsand to evaluate the value of this technique for health screening, disease diagnosis, and prognostic indication. Species studied included bald eagle (Haliaeetus leucocephalus), red-tailed hawk (Buteo jamaicensis), barn owl (Tyto alba), great horned owl (Bubo virginianus), turkey vulture (Cathartes aura), Harris' hawk (Parabuteo unicinctus), Stellar's sea eagle (Haliaeetus pelagicus), barred owl (Strix varia), screech owl (Otus asio), and black vulture (Coragyps atratus). Several clinical cases show the diagnostic/therapeutic value of protein electrophoresis in raptors. This study establishes species-specific reference ranges for several birds of prey and discusses the benefit of electrophoresis as a diagnostic technique in health screens, as a diagnostic aid in conjunction with other tests, and as a prognostic indicator in clinical evaluation of raptors.

Inhibitory effects of naltrexone on the induction of parental behavior in juvenile rats.

Juvenile rats are rapidly responsive to pups soon after weaning, displaying maternal-like behaviors such as licking, retrieving, grouping, and crouching over pups. As juveniles reach 30 days of age, they become less responsive to pups and show increased latencies to display the same parental behaviors. In light of previous data implicating opiates in the display of ongoing maternal behavior, we administered naltrexone, a long-acting opiate antagonist, beginning 5 and 9 days prior to and continuing throughout the period of behavioral testing, which started at 26 or 30 days of age. Male and female juveniles treated with 10 mg/kg of naltrexone SC for 9 days (days 21 to 29 of age) prior to and during behavioral testing (days 30 to 37) showed longer latencies to retrieve, group, and crouch over pups than did the vehicle-injected controls. These results suggest that opioids may have a stimulatory role in parental behavior during this prepubertal period.