Plasma levels of cortisol and corticosteroid-binding globulin (CBG) and hepatic CBG mRNA expression in pre- and postnatal pigs

The relationships among hepatic corticosteroid-binding globulin (CBG) mRNA expression and plasma concentrations of cortisol and CBG was evaluated in fetal pigs (n=7-14 per age) on days 50, 70, 80, 90, and 104 of gestation and postnatal pigs (n=8 per age) on days 1, 3, 10, 20, 30, and 40 following birth. In fetal pigs, hepatic CBG mRNA expression was highest (P<0.01) on day 50 as compared to days 90 and 104, exhibiting an overall negative relationship (r=-0.63; P<0.01) with estimated gestation age. Plasma porcine CBG (pCBG) concentration was correlated (r=0.34; P<0.05) with hepatic CBG mRNA level. Plasma cortisol concentrations were not different over this same period. In postnatal pigs, hepatic CBG mRNA expression increased (P<0.01) from days 3 to 40. The pCBG concentration increased (P<0.01) from days 1 (6.1+/-3.4 microg/ml) to 10 (15.1+/-3.7 microg/ml), while plasma cortisol concentration remained constant. An understanding of the relation between hepatic CBG mRNA and circulating pCBG concentrations may provide insight into the mechanisms determining the bioavailability of cortisol necessary in prenatal development and the conservation of cortisol during postnatal development in the pig.     

Pathogenicity of two recombinant avian leukosis viruses

We have recently described the isolation and molecular characteristics of two recombinant avian leukosis subgroup J viruses (ALV J) with an avian leukosis virus subgroup A envelope (r5701A and r6803A). In the present study, we examined the role of the subgroup A envelope in the pathogenesis of these recombinant viruses. Chickens of line 151(5) x 7(1) were inoculated at 1 day of age with r5701A, r6803A, Rous-associated virus type 1 (RAV-1), or strain ADOL-Hcl of ALV-J. At 2, 4, 10, 18, and 32 wk postinoculation (PI), chickens were tested for avian leukosis virus (ALV)-induced viremia, shedding, and neutralizing antibodies. All except one chicken inoculated with the recombinant viruses (98%) developed neutralizing antibodies by 10 wk PI compared with only 16% and 46% of the ADOL-Hcl and RAV-1-inoculated birds, respectively. ALV-induced tumors and mortality in the two groups inoculated with recombinant viruses were different. The incidence of tumors in groups inoculated with r5701A or RAV-1 was 100% compared with only 9% in the groups inoculated with r6803A or ADOL-Hcl. The data suggest that differences in pathogenicity between the two recombinant viruses might be due to differences in the sequence of the 3' untranslated region (presence or absence of the E element), and, therefore, not only the envelope but also other elements of the viral genome play an important role in the pathogenesis of ALV.     

Analysis of proglycogen and macroglycogen content in muscle biopsy specimens obtained from horses

OBJECTIVE: To determine proglycogen (PG) and macroglycogen (MG) content in equine skeletal muscle and to compare 2 analytical methods (acid hydrolysis [AC] and PG plus MG determination) for measurement of total muscle glycogen content (Gly(tot)) in biopsy specimens. SAMPLE POPULATION: Muscle biopsy specimens obtained from 41 clinically normal horses. PROCEDURE: Forty-five muscle biopsy specimens obtained from the middle gluteal (n = 31) or triceps (14) muscle were analyzed, using AC and MG plus PG determination for Gly(tot). Variability within muscle biopsy specimens for each method was calculated from duplicate analyses of muscle specimens. In a second experiment, variation in MG and PG content between muscle biopsy specimens and the effect of sample collection depth on the concentration of MG and PG in the middle gluteal muscle was evaluated. RESULTS: There was a strong correlation (r = 0.99) between Gly(tot) values obtained by use of AC and MG plus PG determination. Coefficients of variation for within- and between-specimen variability of Gly(tot) were approximately 4% for each method. The PG fraction was always in excess of the MG fraction. Biopsy specimens obtained from the superficial part of the middle gluteal muscle contained significantly more Gly(tot) and PG than specimens obtained from deeper parts. CONCLUSIONS AND CLINICAL RELEVANCE: This study confirms that MG and PG exist in equine skeletal muscle and can be measured reliably in biopsy samples. This technique could be applied in future studies to investigate glycogen metabolism in exercising horses and horses with glycogen-storage diseases.     

Rhodococcus equi pleuropneumonia in an adult horse

A 10-year-old warmblood gelding was evaluated for intermittent pyrexia, dullness, weight loss, and progressive respiratory disease. Multifocal necrotic pneumonia and pleuritis due to Rhodococcus equi infection was diagnosed. Case management is discussed, as well as factors that may have led to this rare cause of pleuropneumonia in an adult horse.     

A strategy for developing educational evaluations for learner,course, and institutional goals

The curricula for both veterinary and human medicine are undergoing review and change as a new and highly competitive practice environment influences what abilities graduates require to be successful. Concerning many is the contention that some graduates lack skills and aptitudes necessary for economic success. If significant changes are to be considered for the curricula of either profession, it will be difficult to plan for meaningful change in the absence of high-quality information about the needs of graduates and related curriculum gaps. The purpose of this article is to argue why educators should design more effective systems of evaluation that are responsive to the needs of educational program planning. One example from a medical school is described. In this case, the authors discuss how their institution's evaluations were insufficient for answering new and important questions that go beyond traditional cognitive measures: specifically, no data set was available that allowed the institution to answer questions about practice environment and curricular innovations. More recently, institutions have become interested in learning to what extent their broad missions are accomplished or not. Similarly, academic leaders are not simply interested in performance of learners on tests of competence; they want to know more about how their graduates are doing in the practice setting. To answer questions such as these, educators must expand their systems of evaluations to address these broader themes. The authors conclude by identifying several lessons learned from their experiences in developing a new system of educational program evaluation.     

Quantification of hepatic and renal cortical echogenicity in clinically normal cats

OBJECTIVE: To quantitatively determine echogenicity of the liver and renal cortex in clinically normal cats. ANIMALS: 17 clinically normal adult cats. PROCEDURE: 3 ultrasonographic images of the liver and the right kidney were digitized from video output from each cat. Without changing the ultrasound machine settings, an image of a tissue-equivalent phantom was digitized. Biopsy specimens of the right renal cortex and liver were obtained for histologic examination. Mean pixel intensities within the region of interest (ROI) on hepatic, renal cortical, and tissue-equivalent phantom ultrasonographic images were determined by histogram analysis. From ultrasonographic images, mean pixel intensities for hepatic and renal cortical ROI were standardized by dividing each mean value by the mean pixel intensity from the tissue-equivalent phantom. RESULTS: The mean (+/- SD) standardized hepatic echogenicity value was 1.06 +/- 0.02 (95% confidence interval, 1.02 to 1.10). The mean standardized right renal cortical echogenicity value was 1.04 +/- 0.02 (95% confidence interval, 1.01 to 1.08). The mean combined standardized hepatic and renal cortical echogenicity value was 1.02 +/- 0.05 (95% confidence interval, 0.99 to 1.04). CONCLUSIONS AND CLINICAL RELEVANCE: Quantitative determination of hepatic and renal cortical echogenicity in cats is feasible, using histogram analysis, and may be useful for early detection of diffuse parenchymal disease and for serially evaluating disease progression.     

Cisplatin and doxorubicin combination chemotherapy for the treatment of canine osteosarcoma: a pilot study

Sixteen dogs with histologically confirmed appendicular osteosarcoma were treated by amputation followed by cisplatin and doxorubicin chemotherapy. All dogs began chemotherapy within 24 hours of surgery. Cisplatin was administered at 50 mg/m2 intravenously (IV) concurrent with saline-induced diuresis. Doxorubicin was administered 24 hours later at 15 mg/m2 as a slow IV bolus. This protocol was given on a 21-day cycle for 4 cycles. No dose delays were required, but dose reduction of doxorubicin was required in 2 dogs because of neutropenia. Thoracic radiography was performed every 2 months after completion of therapy to monitor for metastatic disease. Two dogs were still alive and free from disease at the time of last contact (24 and 75 months, respectively). Postmortem examinations were performed on 13 of the 14 dogs that died. Eight of these dogs were euthanized because of metastatic osteosarcoma. Of the remaining 5 dogs, euthanasia was performed because of complications of idiopathic megaesophagus (n = 1), arthritis (n = 2), and hemangiosarcoma (n = 2). The median disease-free interval and survival times were 15.7 and 18 months, respectively. When compared to a historical group of 36 dogs with appendicular osteosarcoma treated with surgery and 4 doses of cisplatin. both disease-free interval and overall survival were significantly longer in the study population (P < .015 and P < .007, respectively).     

Clinical efficacy of chlortetracycline hydrochloride administered in milk replacer to calves

Two similar groups of 14 calves were housed and fed identically in individual pens on a calf-rearing farm. The groups were balanced for weight and immunological status as determined by zinc sulphate turbidity values. When an outbreak of enteric and respiratory disease occurred one group was treated with 20 mg chlortetracycline hydrochloride/kg bodyweight daily for seven consecutive days, by adding the active ingredient to the milk replacer, while the other group was left untreated. Both groups received additional therapy as required. The calves were examined daily during the period of treatment and the clinical observations were assessed and analysed statistically. There was a significant difference between the clinical scores of the two groups on the second day of treatment (P less than 0.05) and on all subsequent days (P less than 0.01) indicating that the calves receiving chlortetracycline hydrochloride were less affected by the disease outbreak. The abnormal enteric and respiratory signs were associated with several potential pathogens including bacteria, viruses and protozoa. The treatment was therefore effective against enteric and respiratory disease involving several organisms.