Identification of a novel common proviral integration site, flit-1, in feline leukemia virus induced thymic lymphoma.

A new proviral integration site for feline leukemia virus (FeLV), termed flit-1, was identified from feline thymic lymphoma. Among 35 FeLV-related tumors examined, 5 of 25 thymic lymphomas demonstrated proviral insertion within flit-1 locus whereas none of four alimentary and five multicentric lymphomas and one T-lymphoid leukemia examined had rearrangement in this region. Extensive sequence analysis has shown that flit-1, which is noncoding, is conserved on human chromosome 12 and mouse chromosome 15. The human and murine homologs of flit-1 are positioned approximately 30-kb upstream to activin-A receptor type II-like 1 (ACVRL1/ALK1) gene. Expression of ACVRL1 mRNA was examined in two of five lymphomas with flit-1 rearrangement and detected in both of the two whereas normal thymuses and seven lymphoid tumors without flit-1 rearrangement had no detectable expression. Therefore, flit-1 appears to represent a novel FeLV proviral common integration domain that may influence lymphomagenesis as insertional mutagenesis.

Epizootiology and management of feline leukemia virus in the Florida puma.

Feline leukemia virus (FeLV) was not detected in Florida pumas (Puma concolor coryi) in almost 20 yr of surveillance; however, the finding of two FeLV antigen-positive pumas during the 2002-2003 capture season led to an investigation of FeLV in the population. Between January 1990 and April 2007, the proportion of pumas testing FeLV antibody positive increased, with antibody-positive pumas concentrated in the northern portion of puma range. Five of 131 (4%) pumas sampled between July 2000 and April 2007 were viremic, with all cases clustered in Okaloacoochee Slough (OKS). Clinical signs and clinical pathology at capture were absent or included lymphadenopathy, moderate-to-severe anemia, and lymphopenia. All viremic pumas died; causes of death were septicemia (n=2), intraspecific aggression (n=2), and anemia/dehydration (n=1). Outcome after FeLV exposure in pumas was similar to that in domestic cats, with evidence of regressive, latent, and persistent infections. Management of the epizootic included vaccination, and as of April 2007, 52 free-ranging pumas had received one or more inoculations. Vaccinations were concentrated in OKS and in a band between OKS and the remainder of the puma population. There have been no new cases since July 2004; however, the potential for reintroduction of the virus remains.

Efficacy of a scheduled IV cocktail of antiemetics for the palliation of nausea and vomiting in a hospice population.

This is a retrospective analysis of 10 mg metoclopramide, 25 mg diphenhydramine, and 4 mg dexamethasone given intravenous piggyback every 6 hours for nausea or vomiting. Outcome measures were rapidity of symptom relief based on the self-report of the patient and nursing documentation of relief from symptoms of nausea or vomiting. Seven hundred and ninety seven patients were admitted to the inpatient hospice unit during a 2-year period. Sixty-three patients developed nausea or vomiting requiring the cocktail. Fifty-seven patients (90%) had objective response as reflected in nursing notes. Symptom relief was usually noted within 2 days with improvement in oral intake and enjoyment in activities, such as parties and family interactions. Partial relief was noted in patients with gastrointestinal malignancies and peritoneal carcinomatosis even with the addition of other antiemetics to the cocktail.

In vivo expression of GFP transgene delivered via a replicating feline leukemia virus.

We previously described replication-competent feline leukemia virus (FeLV) vectors with high-level and stable expression of a green fluorescent protein (GFP) or a suicide transgene in cell cultures in vitro. Considering that FeLV might potentially be used to deliver therapeutic genes in vivo, we first evaluated the expression of the GFP gene introduced in cats by the FeLV, Rickard subgroup A (FRA) construct. Eight newborn kittens were either inoculated with pFRA-GFP plasmid DNA intradermally, or challenged intraperitoneally with FRA-GFP-infected feline fibroblasts. During a 12-week observation period, five cats were shown to be progressively viremic. Quantitative PCR and RT-PCR analyses of plasma and tissue samples from these cats showed that GFP was retained in FeLV DNA or RNA to a variable degree, ranging from 0.002 to 27.890%. Tissue DNA samples were analyzed by PCR for the status of GFP and the env-transgene complex. While the proviruses carrying the GFP transgene were shown to be minor species, all tissues, however, retained the full-length GFP transgene. Despite the occurrence of predominant species with various deletions in the viral genome, approximately 1-3% of the total cell population was GFP-positive in the lymphoid tissues as visualized by laser confocal microscopy. Co-localization of immunofluorescent cells indicated that CD3-positive T cells, dendritic cells and macrophages were the major targets for GFP expression. These findings on the detectable in vivo expression of GFP for as long as a period of 3 months could be viewed positively for contemplating a therapeutic strategy for control of FeLV infection in the cats.

Effects of calcitriol, seocalcitol, and medium-chain triglyceride on a canine transitional cell carcinoma cell line.

BACKGROUND: Transitional cell carcinoma (TCC) in dogs is associated with high morbidity and mortality. Calcitriol and its analog seocalcitol, combined with medium-chain triglyceride (MCT), have potential for the treatment of this disease. MATERIALS AND METHODS: TCC cells were treated with calcitriol or seocalcitol, alone or combined with MCT. Cell growth, cell cycle kinetics, vitamin D receptor (VDR) localization and expression, and Bcl-2 expression were measured. RESULTS: Canine TCC expresses high levels of nuclear VDR. Furthermore, calcitriol and seocalcitol significantly inhibited cell growth and calcitriol caused G0/G1 cell cycle arrest. Bcl-2 expression was slightly decreased in cells treated with these compounds, although no significant changes in VDR expression were observed. MCT enhanced the growth inhibitory effect of both compounds. CONCLUSION: Calcitriol and seocalcitol inhibited TCC cell growth via induction of cell cycle arrest and MCT enhanced this effect. Therefore, calcitriol and seocalcitol with MCT may have therapeutic potential for canine bladder cancer.

Lentivirus-specific cytotoxic T-lymphocyte responses are rapidly lost in thymectomized cats infected with feline immunodeficiency virus.

To what extent the thymus is needed to preserve the virus-specific cytotoxic T-lymphocyte (CTL) response of lentivirus-infected adults is unclear. Presented here is the first definitive study using thymectomized (ThX) animals to directly evaluate the contribution of thymic function to lentivirus-specific CTL response and the control of lentivirus infections. ThX and mock-ThX cats were inoculated with feline immunodeficiency virus (FIV) and monitored for their FIV-specific CTL responses. Early in infection, both FIV-ThX and FIV-mock-ThX cats produced similar CTL responses, but surprisingly, after 20 weeks, the FIV-ThX cats showed a statistically significant loss of FIV-specific CTL activity, while FIV-infected cats with intact thymuses continued to maintain FIV-specific CTL. The loss of CTL did not affect plasma virus load, which remained elevated for both groups. These results emphasize the importance of thymic integrity in maintaining immunity to lentiviruses, but also bring into question the notion that virus load is regulated predominantly by the virus-specific CTL response.

Expression of equine glucose transporter type 4 in skeletal muscle after glycogen-depleting exercise.

OBJECTIVES: To clone and sequence cDNA for equine insulin-responsive glucose transporter (glucose transporter type 4 [GLUT-4]) and determine effects of glycogen-depleting exercise and meal type after exercise on GLUT-4 gene expression in skeletal muscle of horses. SAMPLE POPULATION: Muscle biopsy specimens from 7 healthy adult horses. PROCEDURES: Total RNA was extracted from specimens, and GLUT-4 cDNA was synthesized and sequenced. Horses were exercised on 3 consecutive days. On the third day of exercise, for 8 hours after exercise, horses were either not fed, fed half of daily energy requirements as hay, or fed an isocaloric amount of corn. The GLUT-4 mRNA was determined by use of real-time reverse transcriptase-polymerase chain reaction in muscle biopsy specimens obtained before 3 consecutive days of exercise and within 10 minutes and 4, 8, and 24 hours after the third exercise bout. RESULTS: A 1,629-bp segment was sequenced, of which 1,530 bp corresponded to the coding region end encoded a protein of 509 amino acids. Expression of GLUT-4 gene increased by 2.3, 4.3, 3.3, and 2.6 times 10 minutes and 4, 8, and 24 hours after exercise, respectively, compared with that prior to exercise. No differences were observed in GLUT-4 gene expression among conditions of feed withholding, corn feeding, and hay feeding during the 8 hours postexercise. CONCLUSIONS AND CLINICAL RELEVANCE: Lack of increase of GLUT-4 gene expression after grain feeding and exercise may explain the apparently slower rate of glycogen synthesis after exercise in horses relative to that of other species.

Animal models of retroviral encephalopathies: feline model.

Human immunodeficiency virus infection in children and adults results in a progressive neurodegenerative disease consistent with a predominant subcortical mediated dementia. Techniques for developing a feline model of the early stages of lentiviral-associated neurodegeneration are presented. The behavioral, neurophysiologic, immunologic, virologic, and neuropathologic aspects of this model are also described.