Effects of fescue toxicosis on bull growth, semen characteristics, and breeding soundness evaluation.

Tall fescue possesses heat, drought, and pest resistance conferred to the plant by its mutualistic relationship with the ergot alkaloid producing fungal endophyte, Neotyphodium coenophialum. The objective of this study was to evaluate the impact of ergot alkaloid consumption on growth, scrotal circumference (SC), and semen quality. The SC measurement and percentage of motile and normal sperm were used to determine if a bull passed the breeding soundness exam (BSE) requirements. Bulls (n = 14) between 13 and 16 mo of age exhibiting ≥32 cm SC and having passed a BSE were assigned to 1 of 2 dietary treatments accounting for BCS and BW. Bulls were fed the treatment diet containing toxic tall fescue seed (E+; 0.8 µg of ergovaline and ergovalanine/g DM) or the control diet containing endophyte-free nontoxic tall fescue seed (E-) for 126 d. Blood samples were collected and BSE and BCS accessed at the start of the test (d 0) and every 21 d to the end of test (d 126). Weights were obtained on d 0 and d 126. Serum prolactin (PRL) concentrations were affected by treatment × day interactions (P = 0.04) verifying the effectiveness of the E+ diet. Bulls consuming the E+ diet exhibited declining PRL concentrations from 250 ± 52.1 ng/mL on d 0 to 30.6 ± 46.9 ng/mL by d 126 whereas bulls receiving the E- ration maintained serum PRL concentrations greater than or equal to 226.7 ± 50.4 ng/mL across the 126-d study. Body condition score (P = 0.4) and BW (P = 0.4) were not different between treatments. No difference due to treatment was observed for the percentage of bulls passing a standard BSE exam (P = 0.6) and no treatment effect was observed for any semen characteristic measured by computer-assisted semen analysis (CASA; P ≥ 0.2). The SC was negatively affected by treatment × day interaction (P = 0.04) with E- bulls exhibiting a larger SC at d 126 compared with E+ bulls of 36.7 ± 0.8 versus 34.3 ± 0.8 cm, respectively. Within treatment, E+ bulls exhibited a decrease in SC (P = 0.0001) with a d 0 SC of 37.3 ± 0.8 cm and dropping to 34.3 ± 0.8 by d 126. Theoretically, reduced SC would negatively impact semen quality, but this was not observed. However, CASA and BSE evaluation data are consistent with recent reports indicating that bulls grazing E+ tall fescue exhibited only subtle, if any, differences on semen characteristics.

Endocardial fibroelastosis in a quarterhorse mare.

A 4-year-old crossbred Quarterhorse mare was submitted to the Clemson Veterinary Diagnostic Center for necropsy examination with a chronic history of inappetence, weight loss and lethargy. Prior to death the horse had developed mild diarrhoea and began showing evidence of colic. Necropsy examination revealed a markedly enlarged heart due predominantly to marked dilation of the right atrium, tortuous congested mesenteric blood vessels, marked ascites, pleural effusion and pulmonary oedema. Further examination of the heart showed the endocardium of the left side of the heart, including the mitral valve leaflets, to be diffusely thickened. Microscopically, the endocardial thickening was due to deposition of fibrous connective tissue and elastin fibres. These findings are consistent with a diagnosis of endocardial fibroelastosis.

Pharyngeal odontoma in an adult walleye (Sander vitreus).

An adult walleye (Sander vitreus) was submitted to Cornell University for evaluation of a hard pale-tan pharyngeal mass attached to the gill arches. Dozens of hard white conical structures radiated from the surface. Microscopically, conical structures were identified as denticles and rested on plates of dysplastic orthodentine, cementum, and acellular bone. A diagnosis of compound odontoma was made based upon the presence of proliferative epithelial and mesenchymal odontogenic tissues that recapitulated tooth structures normally present on gill rakers. Odontomas are classified as hamartomas and typically develop in immature diphyodont mammals. The pharyngeal location and lifelong regeneration of teeth in fish, however, both qualify the present diagnosis in the pharyngeal region of an adult teleost. Ontogenic and morphologic differences between mammalian and piscine dentition and differentials for tooth-bearing tumors in fish are presented within the context of a developmental anomaly.

Acute pancreatitis in two five-day-old Appaloosa foals.

Severe acute pancreatitis (SAP) in foals is rare and treatment has not been documented. This paper describes the clinical, haematological and ultrasonographic findings as well as attempted treatment of SAP in two 5-day-old Appaloosa fillies. Clinical signs, including colic, diarrhoea and coma, may be mistaken for sepsis or neonatal encephalopathy. Hyperlipaemic serum and peritoneal fluid, and elevated serum and peritoneal fluid amylase and lipase activities aided the diagnosis. Severe acute pancreatitis should be included as a differential in an acutely ill foal with diarrhoea, colic, cerebral cortica dysfunction and hyperlipaemia.

Benign placental mass with fetal growth retardation in a bull mastiff.

A 4-year-old bull mastiff presented due to premature labour. The referring veterinarian elected to perform a caesarian delivery and at the time of surgery a 4×4×2 cm round, smooth, red to tan, lobulated soft mass was identified attached to the allantoic surface of the zonary placenta of one pup. Microscopically, this mass was composed of loosely arranged confluent undulating cords of polygonal to columnar epithelioid cells separated by a fine fibrovascular stroma resembling the placental labyrinth. The labyrinthine structure and epithelioid nature of the cells suggested that the mass was of trophoblastic origin. Due to the non-invasive nature of the mass and relatively low mitotic activity, this proliferative trophoblastic mass was considered to be benign. The absence of morphological features supporting malignant behaviour and the recapitulation of the normal labyrinthine architecture led to the diagnosis of a trophoblastic hamartoma. To the authors' knowledge this is the first report of a placental hamartoma in the dog.

Characterization of the host response in systemic isosporosis (atoxoplasmosis) in a colony of captive American goldfinches (Spinus tristis) and house sparrows (Passer domesticus).

Systemic isosporosis, also known as atoxoplasmosis, is a common parasitic disease of passerines. Infection is thought to be endemic in wild birds with fulminant, fatal disease occurring under the influence of stress, concurrent infections, or immunosuppression. Here, we describe the histologic and immunohistochemical characteristics of the cellular infiltrate occurring in captive colonies of American goldfinches and house sparrows. Necropsies were performed on 9 birds, and histologic examination was performed on the intestines of 7 additional birds. Lesions were most severe in the proximal small intestines. Histologically, the changes ranged from variably intense infiltrates of lymphocytes that filled the lamina propria to sheets of large, atypical cells that expanded and obliterated normal mucosal epithelium and invaded through the wall of the intestine and into the ceolomic cavity. Both the smaller lymphocytes and large atypical cells were immunoreactive for CD3. Intracellular parasites consistent with Isospora were detected in the large atypical cells, but they were more easily detectable in the more differentiated lymphocytes. Polymerase chain reaction and virus isolation performed on tissues from 7 birds were negative for retroviruses and herpesvirus. The immunohistochemical results of this study and the destructive nature of the cellular infiltrate suggest that the lesion represents T-cell lymphoma. In birds, lymphomas are most often associated with herpes and retroviruses; the absence of these viruses suggests that the parasite initiated neoplastic transformation. Though much work needs to be done to prove the transformative nature of the lesions, these preliminary results suggest that passerine birds may be susceptible to parasite-associated lymphomas.

SAR studies on a novel series of human cytomegalovirus primase inhibitors.

A novel series of imidazolylpyrimidines were found to possess inhibitory activity against the human CMV UL70 primase. Extensive SAR studies on an HTS lead led to potent, orally bioavailable compounds with anti-CMV IC(50) values of 150 nM in both viral yield and viral DNA replication assays and with a much reduced cytotoxicity compared to marketed treatments ganciclovir and cidofovir.

Discovery of a novel series of inhibitors of human cytomegalovirus primase.

Infection by human cytomegalovirus (hCMV) remains a potent threat to susceptible people throughout the world. We have discovered a series of imidazolyl-pyrimidine compounds, which were found to be irreversible inhibitors of the hCMV UL70 primase based on results from radiolabeling and SAR studies. Two promising analogs are described that rival ganciclovir and cidofovir in antiviral potency and possess improved cytotoxicity profiles.

The Department of Veterans Affairs' role in Federal Emergency Management.

The Veterans Health Administration (VHA) has been increasingly called on to provide disaster relief health care personnel and other emergency assistance since the role of the Department of Veterans Affairs in emergency management was expanded by the Federal Response Plan in 1992. This article briefly reviews the VHA's emergency management functions currently specified by the Federal Response Plan and its present activities in procuring and maintaining antidotes, antibiotics, and other pharmaceutical stockpiles to be used in response to terrorist incidents involving weapons of mass destruction. In view of VHA's national scope and extensive assets, its administration by the government, and its critical role in health professional training, there are several additional ways that VHA could economically augment the federal government's efforts to better support and prepare local jurisdictions for disasters or incidents involving weapons of mass destruction, if the required authorization and funding were provided.

Expressed sequences from conidial, mycelial, and sexual stages of Neurospora crassa.

In the Neurospora Genome Project at the University of New Mexico, expressed sequence tags (ESTs) corresponding to three stages of the life cycle of the filamentous fungus Neurospora crassa are being analyzed. The results of a pilot project to identify expressed genes and determine their patterns of expression are presented. 1,865 partial complementary DNA (cDNA) sequences for 1,409 clones were determined using single-pass sequencing. Contig analysis allowed the identification of 838 unique ESTs and 156 ESTs present in multiple cDNA clones. For about 34% of the sequences, highly or moderately significant matches to sequences (of known and unknown function) in the NCBI database were detected. Approximately 56% of the ESTs showed no similarity to previously identified genes. Among genes with assigned function, about 43.3% were involved in metabolism, 32.9% in protein synthesis and 8.4% in RNA synthesis. Fewer were involved in defense (6%), cell signalling (3.4%), cell structure (3.4%) and cell division (2.6%).

Metal-coordination sphere in the methylated Ada protein-DNA co-complex.

BACKGROUND: The Ada protein of Escherichia coli repairs methyl phosphotriesters in DNA by direct, irreversible methyl transfer to one of its own cysteine residues. This residue, Cys69, is ligated to a tightly bound zinc ion in the protein. After methyl transfer, Ada can bind DNA sequence-specifically, inducing the transcription of genes that confer resistance to the toxic effects of methylating agents. Coordination of zinc via a thioether-S is exceedingly rare. We therefore investigated whether methylation causes ligand exchange of Cys69, replacing the thioether with a new zinc ligand with higher affinity for the metal. RESULTS: We added a 13C-labeled methyl group to Cys69 of Ada and used isotope-edited NMR to observe the behavior of its protons. Comparison of the spectra for the Zn- and 112Cd-bound forms of the methylated protein with that of the 113Cd-bound form provided clear evidence that S-Me-Cys69 is coordinated to the metal in Ada when Ada is bound specifically to DNA. CONCLUSIONS: The transcriptionally competent form of Ada, in which Cys69 is methylated and the protein is bound to DNA, maintains the coordination of S-Me-Cys69 to the metal ion. Thus, ligand exchange is not responsible for switching Ada from a DNA-repair protein to a transcriptional activator. We propose that the lability of the thioether-zinc coordinate bond may provide a mechanism for down-regulation of the adaptive response by inactivation of the Ada DNA-binding domain.