Growth hormone receptors in the porcine testis during prepuberty.

Supplementation of exogenous growth hormone (GH) during prepuberty advances onset of spermatogenesis in boars, but the mechanism of action is unknown. The present study is an investigation of the presence and characteristics of testicular growth hormone receptors (GHR). A total of 36 boars were castrated, three boars every 10 days, between the ages of 10 and 120 days. Testicular membrane preparations of 10, 20, 30, 50, 70, 100 and 120-day-old boars were used to determine (125)I-bGH binding and Scatchard analysis. Liver from a 60-kg barrow was used for comparison. Specific (125)I-bGH binding to testicular membrane preparations occurred in all age groups with the exception of 20-day-old boars at levels of 30-40% of liver binding. At 30 days of age the unlabelled bGH at 1.1 ng/tube achieved half maximal inhibition (ID(50)). Results of Scatchard analysis indicated a single class of binding sites. Binding affinity was 2.89 x 10(9) m with a binding capacity of 12 fmole/mg membrane protein. The results from this study suggest that GH may act directly on the cells of the prepubertal boar testis.

Alternative model for teaching microsurgery.

Animals have been widely used as a training model for teaching microsurgery. However, unlimited access to the animal laboratory is not always possible, and increased scrutiny of the ethical use of laboratory animals is a major factor to consider when teaching microsurgery. In such situations, an alternative method is required for microsurgical training techniques, such as medical grading tubes, and surgical gloves. These alternative teaching tools provide an ideal training model and present an alternative for teaching microsurgical techniques. They are readily available and abundant in the laboratory. In addition, these alternative tools can be used to provide initial training before entering the clinical setting. A practice card designed from surgical gloves and medical grading tube was used to practice simple sutures. The training progressed to a more difficult level, using medical-grade tubing for end-to-end anastomosis, end-to-side anastomosis, side-to-side anastomosis, and free graft placement. This alternative proved challenging for the trainees, but improved hand coordination was observed. The alternative models familiarized trainees with the instruments and with developing a surgical approach before moving on to more clinical settings. The use of surgical gloves and medical grading tubes resulted in a significant reduction in the numbers of laboratory animals used for teaching microsurgery, as well as reduced cost.