Expression of connexin 43 protein in testes, epididymides and prostates of stallions

REASONS FOR PERFORMING STUDY: Connexin 43 (Cx43) is a ubiquitously distributed gap junction protein in testes and other reproductive tissues. Adjacent cells share ions and small metabolites through intercellular channels, which are present in gap junctions. Previously, Cx43 has not been reported in testes, epididymides and prostates either in healthy stallions or cryptorchid horses. OBJECTIVES: To demonstrate the expression pattern of Cx43 in the reproductive tissues of stallions and examine whether naturally occurring bilateral cryptorchidism has any influence on distribution and expression of Cx43. METHODS: The expression and the presence of Cx43 protein were detected by means of immunohistochemistry and Western blot analysis using a polyclonal rabbit anti-Cx43 antibody. RESULTS: In stallions, gap junctions appeared as structures localised to cell-cell contacts between adjacent cells. In testes, Cx43 expression was detected in the interstitial tissue and seminiferous tubules, between Leydig and Sertoli, as well as Sertoli and germ cells. In epididymides, Cx43 was localised between epithelial cells, whereas in prostates, between secretory cells of the glandular epithelium. In the cryptorchid, a clear reduction of Cx43 signal was observed in all reproductive tissues. CONCLUSIONS: Coupling of Leydig cells via gap junctions may suggest that steroidogenic function of the testis is under the influence of these intercellular channels. Within seminiferous tubules, the expression was found to be stage-specific, pointing to its role in coordinating spermatogenesis. Differential distribution of Cx43 protein in the reproductive tract of normal and cryptorchid stallions indicates that expression is clearly dependent on the physiological status of the horse. POTENTIAL RELEVANCE: Detection of Cx43 expression in equine testicular, epididymal, and prostatic cells is important for a better understanding of the role of intercellular membrane channels in direct cell communication within the reproductive tract of stallions.     

Improving response rates: introducing an anonymous longitudinal survey research protocol for veterinary medical students

With the Journal of Veterinary Medical Education's recent summer 2005 theme issue on stress, the mental-health concerns of veterinary medical students has been brought to the forefront of the field. Since it is anticipated that research on this topic will continue and that educational institutions may implement changes based upon these results, it is of the utmost importance that this research be of the highest quality. Of particular concern with human-subject inquiries are response rates and confidentiality. In order to accommodate these concerns, an example of a survey research protocol that promotes high response rates and minimizes threats to internal validity influenced by student mistrust in assurances of confidentiality is presented. Specifically, the protocol is designed to ensure anonymity and to preserve the ability to track students longitudinally through the use of anonymous longitudinal identifiers. This protocol was tested with the first-year class of veterinary medical students at Kansas State University in October 2004 and March 2005. The two data collection periods yielded 90% and 76% response rates, respectively. The matching rate of participants, according to the anonymous longitudinal identifiers from Time 1 to Time 2, was 88%.     

Factors associated with practice decisions of Nebraska veterinarians regarding type of practice and community size

Nebraska veterinary practitioners were surveyed to collect data about background characteristics and other factors related to veterinarians' decision to include or not include food animals in their practices and to practice in rural versus urban communities. Background characteristics that were significantly (p < or = 0.05) associated with choosing food-animal practice included growing up on a working farm or ranch; having parents who owned livestock; growing up in a town with a population of less than 10,000; majoring in animal science at university; being male; and having a primary interest, at the time of entering veterinary college, in food animal-exclusive or mixed-animal veterinary practice. The primary factor for choosing the community in which to practice was rural/urban lifestyle for rural veterinarians, while this factor was second for urban veterinarians. For all groups of veterinarians, the primary consideration in selecting their current practice was the species orientation of the practice. The primary reason for not choosing food-animal practice was better working conditions and lifestyle in companion-animal practice, followed by greater interest elsewhere.     

North American veterinary pathology residency training programs: an overview of where they are today and where they were five years ago, with an analysis of trends

An e-mail/telephone survey of all active North American residency training programs in veterinary pathology was conducted in September 2005. The purpose of this survey was to determine current numbers of trainees, their program length and type, and salaries; to compare current numbers to five years earlier; and, finally, to gauge interest in expanding current programs. All 41 training institutions contacted responded to the survey. Briefly, the survey found that there are currently 235 veterinary pathology residents, for a mean of 5.7 residents per training program. The number of residents currently in training programs and the number of applicants for these programs has increased compared to five years earlier. There is widespread interest in further expanding capacity in these programs, and the coalition of the American College of Veterinary Pathologists and the Society of Toxicologic Pathology is a well-known source of possible funding for additional residents. This survey report further documents the numbers of combined residency/PhD programs, average starting salaries for new residents, outside sponsorship effects on pathology training programs, and some of the common concerns regarding veterinary pathology training programs voiced by the respondents. While residency training capacity has expanded in the last five years, and there is widespread desire to further expand these training programs, a shortage of veterinary pathologists for future market needs will need to be addressed by increased funding from as yet unspecified sources.     

Papillary muscle measurements in cats with normal echocardiograms and cats with concentric left ventricular hypertrophy

BACKGROUND: Papillary muscle hypertrophy can occur in conjunction with, or as the only indication of, hypertrophic cardiomyopathy or other diseases that result in left ventricular concentric hypertrophy (LVCH). Assessment of papillary muscle size is usually subjective because objective measures have not been reported. HYPOTHESIS: The study hypothesis was that papillary muscle dimensions are different between normal cats and cats with LVCH. ANIMALS: Echocardiograms from 44 normal cats and 40 cats with LVCH were included in the study. METHODS: All measurements were taken from the right parasternal short-axis view at the level of the papillary muscles at end-diastole. Three methods were used to assess papillary muscle size: the area subtraction method, the direct area trace method, and the diameter method. Measurements were compared between cat groups and method comparisons were made among methods for area determination. RESULTS: Cats with LVCH were older and had significantly greater left ventricular septal and free wall thicknesses and larger left atrial measurements than normal cats (P < .0006). Papillary muscle measurements were significantly greater by all measurement methods in cats with LVCH than in cats with normal echocardiograms (P < .0001). The area subtraction method and direct area trace method showed moderate agreement. CONCLUSIONS AND CLINICAL IMPORTANCE: Papillary muscle measurements were larger for LVCH cats than normal cats; however, some overlap was present. The establishment of these objective measures adds to the echocardiographic examination of cats.     

Day-to-Day variation of the urine protein: creatinine ratio in female dogs with stable glomerular proteinuria caused by X-linked hereditary nephropathy

BACKGROUND: Interpretation of serial urine protein:creatinine (UPC) values is confounded by a lack of data regarding random biologic variation of UPC values in dogs with stable glomerular proteinuria. HYPOTHESIS: That there is minimal day-to-day variability in the UPC of dogs with unchanging proteinuria and the number of measurements needed to reliably estimate UPC varies with the magnitude of proteinuria. ANIMALS: Forty-eight heterozygous (carrier) female dogs with X-linked hereditary nephropathy (XLHN) causing stable proteinuria. METHODS: Urine samples were obtained daily by cystocentesis for 3 consecutive days on 183 occasions (549 samples). The UPC was measured for each sample with a single dry-film chemistry auto-analyzer. Data were analyzed retrospectively by a power of the mean model because the variance of UPC values within the 3-day evaluation periods increased as the magnitude of proteinuria increased. RESULTS: To demonstrate a significant difference (P < .05) between serial values in these proteinuric dogs, the UPC must change by at least 35% at high UPC values (near 12) and 80% at low UPC values (near 0.5). One measurement is adequate to reliably estimate the UPC when UPC <4, but 2-5 determinations are necessary at higher UPC values. CONCLUSIONS AND CLINICAL IMPORTANCE: These guidelines for interpretation of serial UPC values in female dogs with XLHN may also be helpful for interpretation of UPC values in dogs with other glomerulopathies.     

Plethysmographic comparison of breathing pattern in heaves (recurrent airway obstruction) versus experimental bronchoconstriction or hyperpnea in horses

BACKGROUND: Horses with recurrent airway obstruction (heaves) are described as exhibiting "increased abdominal effort," but it is unknown whether this translates to an effective contribution to ventilation. HYPOTHESIS: We hypothesized that heaves is characterized by asynchrony between rib cage and abdominal motions, and that the abdominal component is the major contributor to ventilation. ANIMALS: The rib cage versus abdominal motion in naturally occurring heaves (n = 15) was compared to controls at rest (n = 7) and during hyperpnea because of lobeline treatment, and the effects of histamine-induced bronchoconstriction in controls (n = 10). METHODS: Flow patterns, phase angle (theta) between the rib and abdominal compartments, abdominal (Vabd) contribution to tidal volume (VT), and lung mechanics were measured. RESULTS: Findings unique to the heaves group included the loss of biphasic expiratory flow, severely increased theta with the abdomen consistently lagging behind the rib cage, and a reduced contribution of the abdomen to ventilation. A subgroup of heaves (n = 5) with abdominal paradox showed a significant (P < .05) reduction in tidal volume, and increased respiratory rate. Bronchodilation reduced theta in heaves (P = .06), but theta remained significantly higher after bronchodilation than found in controls. CONCLUSIONS AND CLINICAL IMPORTANCE: We conclude that breathing pattern in horses with heaves is characterized by severe rib cage/abdominal asynchrony, with the rib cage motion in synchrony with flow, therefore dominating ventilation. In a subset of heaves, the abdominal compartment (diaphragm, abdominal muscles) was completely out of synchrony with flow ("abdominal paradox") despite the clinical appearance of "increased abdominal effort."     

Insulin-like growth factor I in growing thoroughbreds

The objective of this longitudinal study was to characterize growth and plasma insulin-like growth factor I (IGF-I) concentrations in pasture-raised thoroughbreds fed two sources of dietary energy. Mares and foals were randomly assigned to either a sugar and starch (SS) or fat and fibre (FF)-rich feed, and plasma IGF-I and growth were measured once a month from 1 to 16 months of age. These dependent variables were also compared with day length and ambient temperature. There was an association between plasma IGF-I concentration and average daily gain (ADG) (r = 0.32, p < 0.001). There were also clear seasonal patterns in both ADG and plasma IGF-I, with high values in June and May, and a low value in March. Plasma IGF-I and ADG were positively associated with day length and temperature. Plasma IGF-I was never higher (p > 0.10) in the FF group when compared with the SS group, and was higher in the SS group during a rapid growth phase in the spring of year 2 (p < 0.10). The results establish an association between ADG and IGF-I in the horse and indicate that environment and age may influence this relationship. In addition, plasma IGF-I is influenced by dietary energy source at particular times of year. This link has important implications in designing feeding management strategies that are aimed at addressing skeletal development.     

The reproductive performance of dairy cows with anovulatory anoestrus that were injected with either gonadotrophin-releasing hormone or oestradiol benzoate as part of a re-treatment process after insemination

This experiment compared the reproductive performance of synchronised anoestrous dairy cows that were treated initially with a combination of progesterone and oestradiol benzoate and then with either gonadotrophin-releasing hormone (GnRH) or oestradiol benzoate to resynchronise returns to service. It was hypothesised that injecting anoestrous dairy cows with GnRH 12-15 days after insemination and coinciding with the time of insertion of a controlled intravaginal progesterone-releasing (CIDR) device would increase conception rates to the preceding 1st insemination compared with oestradiol benzoate treated cows; both GnRH and oestradiol benzoate would resynchronising the returns to service of those cows that did not conceive to the preceding insemination. Groups of cows in 11 herds were presented for a veterinary examination after they had not been seen in oestrus postpartum. Those cows diagnosed with anovulatory anoestrus (n = 1112) by manual rectal palpation and/or ultrasonography were enrolled in the trial. Each enrolled cow was injected with 2 mg oestradiol benzoate i.m. on Day -10, (where Day 0 was the 1st day of the planned insemination) concurrently with vaginal insertion of a CIDR device. The device inserted was withdrawn on Day -2 and then each cow injected i.m. with 1 mg of oestradiol benzoate on Day -1 unless it was in oestrus. Observation for oestrus preceded each insemination. Every cow that had been inseminated on Days -1,0,1 or 2 was presented for treatment for resynchrony on Day 14 (n = 891). They were divided into 2 groups; those with an even number were each injected i.m. with 250 microg of a GnRH agonist (Treatment group n = 477); each of the cows with an odd number injected i.m. with 1 mg of oestradiol benzoate (control group, n = 414). Each GnRH or oestradiol benzoate injection preceded reinsertion of a CIDR device previously inserted from Days -10 to -2. It was withdrawn on Day 22, 24 hours before injecting 1 mg oestradiol benzoate. Cows observed in oestrus were submitted for a 2nd insemination. Every enrolled cow still present in the herd was pregnancy tested by palpation of uterine contents per rectum about 6 weeks later and again at the end of a herd's seasonal breeding programme. The alternative use of GnRH instead of oestradiol benzoate did not affect the percentage of cows conceiving within 3 days of the mating start date (MSD) (35.6 % vs 35.3 %, P = 0.90), resubmission rates for a 2nd insemination among cows not pregnant to the 1st insemination (81.6 % vs 83.5 %, P = 0.41), 6-week pregnancy rate (59.3 % vs 60.6 %, P = 0.65), 21-weekpregnancy rate (86.6 vs 85.0, P = 0.36), mean interval from MSD to conception (32.5 +/- 1.8 days vs 29.9 +/- 1.8 days, P = 0.26) or conception rate of cows reinseminated by Day 28 (43.3 % vs 38.8 %, P = 0.39). When GnRH was compared with oestradiol benzoate, it did not increase conception rates to the 1st service; it was as effective as oestradiol benzoate in synchronising returns to service in previously treated anoestrous cows that did not conceive to the 1st service. Its use affected neither conception rates to the preceding 1st inseminations nor to the following 2nd inseminations.