Pathogenesis of a bovine enterovirus-1 isolate in experimentally infected calves.

The pathogenesis and virulence of Bovine enterovirus-1 (BEV-1) in cattle is largely unknown. Reports concerning its virulence suggest that there might be an association between BEV-1 infections and a range of diseases in cattle that vary from respiratory to enteric to reproductive disease and infertility. In the current study, the pathogenesis associated with acute infection of BEV-1 in calves experimentally inoculated with the Oklahoma isolate of BEV-1 was described. Although interpretation of the study was limited by lack of an effective control group, results suggest that an association between inoculation of BEV-1, virus localization, and the potential development of lesions in the brain and heart probably exists. In the experiment, BEV-1 virus localized to the terminal ileum, ileocecal and cecocolonic junctions, spiral colon, and ileocecal lymph nodes; BEV-1 virus was detected in the cytoplasm of enterocytes, lamina propria macrophages, endothelium, neurons of the submucosal and myenteric plexi, and lymphocytes of the submucosal lymphoid tissue. Although no clinical signs were noted following acute infection, BEV-1 was localized in the cerebellar white matter of a calf with encephalitis and in the heart of another calf with coronary arteritis. The current study suggests that the BEV-1 isolate is infectious to young calves and that BEV-1 potentially can have a similar pathogenesis to that observed in natural or experimental enterovirus infections in other species.

Pattern formation and eyespot determination in butterfly wings.

Butterfly wings display pattern elements of many types and colors. To identify the molecular processes underlying the generation of these patterns, several butterfly cognates of Drosophila appendage patterning genes have been cloned and their expression patterns have been analyzed. Butterfly wing patterns are organized by two spatial coordinate systems. One system specifies positional information with respect to the entire wing field and is conserved between fruit flies and butterflies. A second system, superimposed on the general system and involving several of the same genes, operates within each wing subdivision to elaborate discrete pattern elements. Eyespots, which form from discrete developmental organizers, are marked by Distal-less gene expression. These circular pattern elements appear to be generated by a process similar to, and perhaps evolved from, proximodistal pattern formation in insect appendages.

Recruitment of a hedgehog regulatory circuit in butterfly eyespot evolution.

The origin of new morphological characters is a long-standing problem in evolutionary biology. Novelties arise through changes in development, but the nature of these changes is largely unknown. In butterflies, eyespots have evolved as new pattern elements that develop from special organizers called foci. Formation of these foci is associated with novel expression patterns of the Hedgehog signaling protein, its receptor Patched, the transcription factor Cubitus interruptus, and the engrailed target gene that break the conserved compartmental restrictions on this regulatory circuit in insect wings. Redeployment of preexisting regulatory circuits may be a general mechanism underlying the evolution of novelties.

Ki-67 and vascular endothelial growth factor expression in intracranial meningiomas in dogs.

BACKGROUND: Tumor proliferation in human intracranial meningiomas can be defined by the reactivity of the monoclonal antibody MIB-1 to the Ki-67 antigen. Vascular endothelial growth factor (VEGF), a pro-angiogenic factor, is a predictive marker for survival of dogs with intracranial meningiomas. HYPOTHESIS: Ki-67 is expressed in canine intracranial meningiomas and is associated with VEGF expression. Ki-67 expression is a prognostic marker for patient outcome. ANIMALS: Seventy client-owned dogs with WHO grade I intracranial meningiomas. METHODS: Retrospective study assessing the degree of immunostaining for Ki-67 by MIB-1 and VEGF expression in intracranial meningioma tissue from dogs. MIB-1 Labeling Index (LI) was calculated with Image J NIH-software. Extent, intensity, and distribution of VEGF-expression was assessed semiquantitatively. Cross tabulations with Fisher's exact tests and nonparametric Spearman's rank correlations were performed to identify associations between VEGF expression and MIB-1 LI. Fifteen dogs underwent postsurgical radiotherapy and were included in survival analysis. The effect of MIB-1 LI on survival was examined by Kaplan-Meier and Cox proportional hazards regression procedures. RESULTS: Ki-67 staining was positive in 91% (64/70) and VEGF expression was detected in 96% (67/70). There was no significant association between VEGF expression and MIB-1 LI. MIB-1 LI was not associated with survival. CONCLUSIONS AND CLINICAL IMPORTANCE: MIB-1 antibody can be used to document cell proliferation in intracranial meningiomas in dogs, but does not predict outcome. No association between VEGF as a marker of angiogenesis and tumor proliferation was found. Angiogenesis might be a more important predictor of meningioma activity in dogs than is Ki-67.

Comparison of combination l-asparaginase plus CHOP or modified MOPP treatment protocols in dogs with multi-centric T-cell or hypercalcaemic lymphoma.

OBJECTIVES: To compare the progression-free survival of dogs with high-grade T-cell lymphoma treated with either a cyclophosphamide, doxorubicin, vincristine and prednisone-based or a modified mechlorethamine, vincristine, prednisone and procarbazine chemotherapy protocol. MATERIALS AND METHODS: In this retrospective study, cases were selected based on histologic or cytologic diagnosis of lymphoma, T-cell phenotype, hypercalcaemia, or both, and no previous chemotherapy for lymphoma. Treatment was not randomly allocated. RESULTS: Seventy-three dogs were included in this study: 50 in the cyclophosphamide, doxorubicin, vincristine and prednisone group and 23 in the mechlorethamine, vincristine, prednisone and procarbazine group. The median progression-free survival was 133 days for dogs in the cyclophosphamide, doxorubicin, vincristine and prednisone group and 97 days for dogs in the mechlorethamine, vincristine, prednisone and procarbazine group. When golden retrievers (n = 16) were evaluated -separately, progression-free survival was longer in the cyclophosphamide, doxorubicin, vincristine and prednisone versus mechlorethamine, vincristine, prednisone and procarbazine treatment group (median PFS 154 days versus 70.5 days, respectively). CLINICAL SIGNIFICANCE: The progression-free survival time for dogs with multi-centric T-cell lymphoma treated with a modified mechlorethamine, vincristine, prednisone and procarbazine protocol was similar to that of dogs treated with cyclophosphamide, doxorubicin, vincristine and prednisone. Further studies, including those evaluating golden retrievers separately, are needed to confirm these findings.

Interaction of TATA-binding protein with upstream activation factor is required for activated transcription of ribosomal DNA by RNA polymerase I in Saccharomyces cerevisiae in vivo.

Previous in vitro studies have shown that initiation of transcription of ribosomal DNA (rDNA) in the yeast Saccharomyces cerevisiae involves an interaction of upstream activation factor (UAF) with the upstream element of the promoter, forming a stable UAF-template complex; together with TATA-binding protein (TBP), UAF then recruits an essential factor, core factor (CF), to the promoter, forming a stable preinitiation complex. TBP interacts with both UAF and CF in vitro. In addition, a subunit of UAF, Rrn9p, interacts with TBP in vitro and in the two-hybrid system, suggesting the possible importance of this interaction for UAF function. Using the yeast two-hybrid system, we have identified three mutations in RRN9 that abolish the interaction of Rrn9p with TBP without affecting its interaction with Rrn10p, another subunit of UAF. Yeast cells containing any one of these individual mutations, L110S, L269P, or L274Q, did not show any growth defects. However, cells containing a combination of L110S with one of the other two mutations showed a temperature-sensitive phenotype, and this phenotype was suppressed by fusing the mutant genes to SPT15, which encodes TBP. In addition, another mutation (F186S), which disrupts both Rrn9p-TBP and Rrn9p-Rrn10p interactions in the two-hybrid system, abolished UAF function in vivo, and this mutational defect was suppressed by fusion of the mutant gene to SPT15 combined with overexpression of Rrn10p. These experiments demonstrate that the interaction of UAF with TBP, which is presumably achieved by the interaction of Rrn9p with TBP, is indeed important for high-level transcription of rDNA by RNA polymerase I in vivo.

Gamma-glutamyl transferase activity in fetal serum, maternal serum, and amniotic fluid during gestation.

Gamma-glutamyl transferase activity was measured in fetal serum, maternal serum, and amniotic fluid in 173 pregnancies from 15 to 40 weeks' gestation. Fetal serum was obtained in the second trimester by fetoscopy and in the third trimester by umbilical cord puncture at caesarian section or vaginal delivery. Enzyme activities in maternal blood (10 IU/1, SD 2) and fetal blood (88 IU/1, SD 20) remained relatively constant throughout gestation, whereas in the amniotic fluid there was a significant decrease at term from the value in the second trimester (p less than 0.001). Electrophoretic separation of the enzyme showed one isoenzyme in the fetal blood and at least two in the amniotic fluid. The fetal isoenzyme had the same mobility as the major isoenzyme in the amniotic fluid.

Quantitative evaluation of alternative mechanisms of blood disposition of di(n-butyl) phthalate and mono(n-butyl) phthalate in rats.

Phthalate esters are ubiquitous, low-level environmental contaminants that induce testicular toxicity in laboratory animals. The diester is rapidly metabolized in the gut to the monoester, which causes the testicular toxicity. Several physiologically based pharmacokinetic (PBPK) model structures have been evaluated for di(2-ethylhexyl) phthalate (DEHP) and mono(2-ethylhexyl) phthalate (MEHP). The objective of this study was to test these PBPK models for a less lipophilic phthalate diester, di(n-butyl) phthalate (DBP), and monoester, mono(n-butyl) phthalate (MBP). Alternate models describing enterohepatic circulation, diffusion-limitation, tissue pH gradients (pH trapping), and a simpler, flow-limited model were evaluated. A combined diffusion-limited and pH trapping model was also tested. MBP tissue:blood partition coefficients were similar when determined either experimentally by a nonvolatile, vial equilibration technique or algorithmically. All other parameters were obtained from the literature or estimated from MBP blood concentrations following intravenous or oral exposure to DBP or MBP. A flow-limited model was unable to predict MBP blood levels, whereas each alternative model had statistically better predictions. The combined diffusion-limited and pH trapping model was the best overall, having the highest log-likelihood function value. This result is consistent with a previous finding that the pH trapping model was the best model for describing DEHP and MEHP blood dosimetry, though it was necessary to extend the model to include diffusion-limitation. The application of the pH trapping model is a step toward developing a generic model structure for all phthalate esters, though more work is required before a generic structure can be identified with confidence. Development of a PBPK model structure applicable to all phthalate esters would support more realistic assessments of risk to human health from exposure to one or more members of this class of compounds.

Quantitative evaluation of alternative mechanisms of blood and testes disposition of di(2-ethylhexyl) phthalate and mono(2-ethylhexyl) phthalate in rats.

Di(2-ethylhexyl) phthalate (DEHP), a commercially important plasticizer, induces testicular toxicity in laboratory animals at high doses. After oral exposure, most of the DEHP is rapidly metabolized in the gut to mono(2-ethylhexyl) phthalate (MEHP), which is the active metabolite for induction of testicular toxicity. To quantify the testes dose of MEHP with various routes of exposure and dose levels, we developed a physiologically based pharmacokinetic (PBPK) model for DEHP and MEHP in rats. Tissue:blood partition coefficients for DEHP were estimated from the n-octanol: water partition coefficient, while partition coefficients for MEHP were determined experimentally using a vial equilibration technique. All other parameters were either found in the literature or estimated from blood or tissue levels following oral or intravenous exposure to DEHP or MEHP. A flow-limited model failed to adequately simulate the available data. Alternative plausible mechanisms were explored, including diffusion-limited membrane transport, enterohepatic circulation, and MEHP ionization (pH-trapping model). In the pH-trapping model, only nonionized MEHP is free to become partitioned into the tissues, where it is equilibrated and trapped as ionized MEHP until it is deionized and released. All three alternative models significantly improved predictions of DEHP and MEHP blood concentrations over the flow-limited model predictions. The pH-trapping model gave the best predictions with the largest value of the log likelihood function. Predicted MEHP blood and testes concentrations were compared to measured concentrations in juvenile rats to validate the pH-trapping model. Thus, MEHP ionization may be an important mechanism of MEHP blood and testes disposition in rats.

Occupational lead exposure: studies in two brothers showing differential susceptibility to lead.

Unexpected differences in clinical and biochemical findings in two brothers occupationally exposed to the same source of lead for dissimilar lengths of time are presented. Only the brother with the shorter period of lead exposure was anemic and afflicted by nausea, vomiting, abdominal colic and arthralgia. His urinary PBG output yielded the high orders of magnitude found in acute intermittent porphyria in relapse. Prior to administration of a single dose of EDTA (1 g of the calcium disodium salt given intravenously in 325 mL 0.15 mol/L NaCl), his blood lead levels averaged 3.6 mumol/L. The amount of chelatable lead retrieved from his urine, 31 mumol/day, was more than twice that found in his asymptomatic counterpart who was exposed to lead for 13 months and whose pre-EDTA blood lead levels averaged 4.0 mumol/L. Not only the activity of delta-aminolaevulinic acid dehydratase, but also that of uroporphyrinogen I synthetase, was markedly inhibited by lead in red cells of both brothers. These activities were restored to normal levels in vitro by addition to the assay system of zinc and dithiothreitol. This ruled out a coexisting genetic deficiency of either enzyme. The anemia of the symptomatic brother with the shorter period of lead exposure was alleviated by folic acid, 15 mg/day. The differences in findings between the two brothers point to differential susceptibility to lead and illustrate the extent to which symptomatic lead poisoning may mimic biochemical and clinical features of the acute porphyrias.

Thin-walled parallel plate ionization chamber for use with photon and electron beam dosimetry.

The design and construction of a thin-walled parallel plate ionization chamber is described. The chamber makes use of a sputtered collecting electrode. The characteristics of this chamber include low leakage (less than 10(-13) A), no stem effect, and reproducibility within 1%. No polarization effects have been seen for electron beams over an energy range 7-25 MeV while for cobalt 60-25 MV photon beams, it is only 10%-15%.

Histological evaluation of effects produced in alveolar bone following gingival incision with an electrosurgical scalpel.

Gingival incisions were performed distal to each of the two lower incisors on 25 adult male guinea pigs. For every animal, electrosection with an electrosurgical scalpel was used on one side, and a conventional scalpel was used on the other. The surgical instruments in all cases were brought into direct contact with periosteum. Five animals were sacrificed at each postoperative period (12, 24, 48, 72, and 96 hours), and sections of the areas of surgery were prepared by standard laboratory procedures. At 12 hours postoperatively there were far more soft tissue necrosis, a more extensive inflammatory reaction, and greater destruction of periosteum after electrosurgery. No significant changes in osteocyte viability were seen after either technique. However, by 24 hours, many empty lacunae were observed in the bone associated with electrosurgery, such necrosis being even more extensive by 48 hours. In contrast, only very minor, localised areas devoid of some osteocytes were seen after use of the conventional scalpel. By 96 hours the electrosurgical connective tissue wounds were still lined by coagulum, but repair of the scalpel wounds had begun. The periosteum and bone had the same features that were seen at 48 hours. Throughout the study, no increase in osteoclasts was seen in any section, nor were significant changes in adjacent bone marrow observed.

Drug misusers in police custody: a prospective survey.

Approximately 11% of individuals seen by forensic medical examiners in police custody in London are drug misusers. This prospective survey using an anonymized structured questionnaire attempted to define some of the characteristics of this selected group of drug misusers. The study was undertaken in Metropolitan Police Service stations (London, UK) within the area covered by Group IV Forensic Medical Examiners. One hundred and fifty consecutive drug misusers in police custody were assessed. Of these individuals 77% used heroin; 30% used both heroin and cocaine regularly; 72% were injecting drugs; 32% were being prescribed drugs (e.g. methadone) by general practitioners or drug agencies. Those individuals prescribed drugs spent a similar amount per day on illicit drugs as those who were not (100.30 pounds versus 106 pounds). Four per cent of individuals were HIV-positive; 25.7% were hepatitis-B positive. Only 9.7% were aware that prophylaxis for hepatitis-B was possible. Seventy-four per cent had served previous prison sentences and of those 82% had used class A controlled drugs whilst serving the sentence. It is concluded that drug misusers seen in police custody tend to be recidivists. It seems that some clear means of identifying and ensuring referral and attendance at an appropriate agency may be the only way to break the cycle of drug misuse, prison and further drug misuse in this highly (self) selected group of patients.

Effects of prolonged administration of azathioprine on parotid glands of rats: an assessment by electron microscopy.

Electron microscopy demonstrated degranulation, vacuolation, development of cytolysosomes and focal areas of cellular necrosis in the acinar cells of the rat parotid glands following daily administration of 2 mg/Kg azathioprine. The changes were noted after seven days but stopped short of complete acinar and ductal cell destruction after about fifty-six days. Ductal cells were not so noticeably affected and rapid recovery in both cells followed cessation of the drug being complete in most within fourteen days.

Effects of prolonged administration of azathioprine on parotid glands of rats: an assessment by light microscopy.

Azathioprine is principally used therapeutically as an immunosuppressive agent. Its mode of action and its effects on a range of target cells have been extensively studied, and there have been several studies on the side effects in organs and tissues including salivary glands. The studies involving salivary glands have concentrated on single injections of the drug whereas there is clearly a need to document the side effects associated with prolonged administration, the extent to which these effects interfere with structure and function in the tissues, and the extent to which they are reversible following withdrawal of the drug. This paper reported a preliminary study using albino Wistar rats, in which prolonged daily injections of azathioprine resulted in moderately severe changes in glandular architecture and cellular morphology. The severity of these changes did not increase appreciably after approximately fifty-six days of drug administration although the extent of damage at that stage seemed likely to result in significant impediments to glandular function. It is noteworthy and important that withdrawal of the drug after seventy days was followed rapidly by reestablishment of normal histological structure.

Salivary alcohol measurement: use in clinical forensic medical practice.

This report describes the use of a salivary alcohol measurement device in clinical forensic medicine, and concludes that it may be of use in assisting the diagnosis or the assessment of patients in the custodial setting.

Prevalence of HIV risk factors for individuals examined in clinical forensic medicine.

OBJECTIVE: to identify the prevalence of high-risk factors for infection with Human Immunodeficiency Virus (HIV) in individuals examined in clinical forensic medical practice and to determine opinions and attitudes about HIV in this patient group. DESIGN: Anonymised questionnaire completed by consecutive individuals seen in clinical forensic medical practice. SETTING: Police stations in London attended by Group IV forensic medical examiners. SUBJECTS: 518 individuals examined in police stations (including prisoners and suspects, those detained in police custody, police officers and victims of crime). RESULTS: 164 (31.7%) individuals did not respond to the questionnaire because of: 1) refusal (12.6%) 2) inability because of drugs and/or alcohol (11.4%) 3) mental illness/disorder (4.2%) or 4) language difficulties (3.5%). 28.4% of the respondents were in at least one of the 'high-risk' categories for HIV infection. 26.5% were intravenous drug misusers; 15% were prostitutes; 9.8% (or their sexual partners) had lived in Central or East Africa since 1977; 5.9% were male homosexuals and 0.5% were haemophiliacs. 5.1% were infected with HIV or had Acquired Immunodeficiency Syndrome (AIDS). Only 28.8% of individuals always used condoms in short-term sexual relationships. 44.4% of respondents believed that everyone should be tested for HIV. CONCLUSION: Over one-quarter of the respondents were in higher-risk groups for infection with HIV. Almost one-third could or would not respond. It is concluded that it is not possible to identify by questionnaire, individuals at higher risk of HIV infection in forensic medical practice. This reinforces the necessity of observing good clinical practice to reduce contamination risks in this work environment. It is clear that education about risks for HIV infection is still much needed.

Prognostic value of early magnetic resonance imaging in dogs after traumatic brain injury: 50 cases.

BACKGROUND: The prognostic value of early magnetic resonance imaging (MRI) in dogs after traumatic brain injury (TBI) remains unclear. OBJECTIVES: Determine whether MRI findings are associated with prognosis after TBI in dogs. ANIMALS: Fifty client-owned dogs. METHODS: Retrospective study of dogs with TBI that underwent 1.5T MRI within 14 days after head trauma. MRI evaluators were blinded to the clinical presentation, and all images were scored based on an MRI grading system (Grade I [normal brain parenchyma] to Grade VI [bilateral lesions affecting the brainstem with or without any lesions of lesser grade]). Skull fractures, percentage of intraparenchymal lesions, degree of midline shift, and type of brain herniation were evaluated. MGCS was assessed at presentation. The presence of seizures was recorded. Outcome was assessed at 48 h (alive or dead) and at 3, 6, 12, and 24 months after TBI. RESULTS: Sixty-six percent of the dogs had abnormal MRI findings. MRI grade was negatively correlated (P < .001) with MGCS. A significant negative correlation of MRI grade, degree of midline shift, and percentage of intraparenchymal lesions with follow-up scores was identified. The MGCS was lower in dogs with brain herniation (P = .0191). Follow-up scores were significantly lower in dogs that had brain herniation or skull fractures. The possibility of having seizures was associated with higher percentage of intraparenchymal lesions (P = 0.0054) and 10% developed PTE. CONCLUSIONS AND CLINICAL IMPORTANCE: Significant associations exist between MRI findings and prognosis in dogs with TBI. MRI can help to predict prognosis in dogs with TBI.

Canine idiopathic epilepsy: prevalence, risk factors and outcome associated with cluster seizures and status epilepticus.

OBJECTIVES: To evaluate the prevalence of cluster seizures and status epilepticus in dogs with idiopathic epilepsy and determine risk factors for cluster seizure frequency, severity and patient outcome. METHODS: Retrospective review of medical records of 407 dogs with idiopathic epilepsy was made. Follow-up questionnaires were evaluated in cases with cluster seizures. RESULTS: Mean age at diagnosis of idiopathic epilepsy was 4 years. Cluster seizures were documented in 169 (41%) dogs. German shepherds and boxers were significantly (P=0·04 and 0·01, respectively) more likely to suffer from cluster seizures compared to Labrador retrievers. There was no association between the occurrence of status epilepticus and cluster seizures and frequency and severity of cluster seizures and status epilepticus episodes with age or breed. Intact males were twice as likely (P=0·003) than neutered dogs to suffer from cluster seizures. Intact females had significantly (P=0·007) more frequent cluster seizures than neutered dogs. The median survival time for all dogs with cluster seizures was 95 months. Significantly (P=0·03) more dogs with frequent cluster seizures were euthanased because of the cluster seizures. CLINICAL SIGNIFICANCE: There was a high prevalence of cluster seizures in dogs with idiopathic epilepsy. Neutering status appears to influence cluster seizure occurrence with intact females more likely to experience more frequent episodes. Euthanasia is associated with frequency of cluster seizure episodes.