Gonadectomy and Blood Sampling Procedures in the Small Size Teleost Model Japanese Medaka (Oryzias latipes).

Sex steroids, produced by the gonads, play an essential role in brain and pituitary tissue plasticity and in the neuroendocrine control of reproduction in all vertebrates by providing feedback to the brain and pituitary. Teleost fishes possess a higher degree of tissue plasticity and variation in reproductive strategies compared to mammals and appear to be useful models to investigate the role of sex steroids and the mechanisms by which they act. The removal of the main source of sex steroid production using gonadectomy together with blood sampling to measure steroid levels has been well-established and fairly feasible in bigger fish and is a powerful technique to investigate the role and effects of sex steroids. However, these techniques raise challenges when implemented in small size teleost models. Here, we describe the step-by-step procedures of gonadectomy in both males and female Japanese medaka followed by blood sampling. These protocols are shown to be highly feasible in medaka indicated by a high survival rate, safety for the life span and phenotype of the fish, and reproducibility in terms of sex steroid clearance. The use of these procedures combined with the other advantages of using this small teleost model will greatly improve the understanding of feedback mechanisms in the neuroendocrine control of reproduction and tissue plasticity provided by sex steroids in vertebrates.

Technological Advances in Surgical Equipment in Exotic Pet Medicine.

Surgery can be challenging in exotic pets owing to their small size and blood volume, and their increased anesthetic risk compared with small animals. Various devices are available to facilitate suturing, cutting, and hemostasis in the human and veterinary fields. These surgical equipment improve the simplicity, rapidity, and effectiveness of surgery. Vessel-sealing devices, radiosurgery, lasers, and ultrasound devices are commonly used because of their ease of use and increase in surgical efficiency. Other surgical devices are available (eg, stapling devices) but are not discussed in this article.

First clinical experiences with a high field 1.5 T MR linac.

Purpose: A 1.5 T MR Linac (MRL) has recently become available. MRL treatment workflows (WF) include online plan adaptation based on daily MR images (MRI). This study reports initial clinical experiences after five months of use in terms of patient compliance, cases, WF timings, and dosimetric accuracy. Method and materials: Two different WF were used dependent on the clinical situation of the day; Adapt To Position WF (ATP) where the reference plan position is adjusted rigidly to match the position of the targets and the OARs, and Adapt To Shape WF (ATS), where a new plan is created to match the anatomy of the day, using deformable image registration. Both WFs included three 3D MRI scans for plan adaptation, verification before beam on, and validation during IMRT delivery. Patient compliance and WF timings were recorded. Accuracy in dose delivery was assessed using a cylindrical diode phantom. Results: Nineteen patients have completed their treatment receiving a total of 176 fractions. Cases vary from prostate treatments (60Gy/20F) to SBRT treatments of lymph nodes (45 Gy/3F) and castration by ovarian irradiation (15 Gy/3F). The median session time (patient in to patient out) for 127 ATPs was 26 (21-78) min, four fractions lasted more than 45 min due to additional plan adaptation. For the 49 ATSs a median time of 12 (1-24) min was used for contouring resulting in a total median session time of 42 (29-91) min. Three SBRT fractions lasted more than an hour. The time on the MRL couch was well tolerated by the patients. The median gamma pass rate (2 mm,2% global max) for the adapted plans was 99.2 (93.4-100)%, showing good agreement between planned and delivered dose. Conclusion: MRL treatments, including daily MRIs, plan adaptation, and accurate dose delivery, are possible within a clinically acceptable timeframe and well tolerated by the patients.

Ligation of the spermatic cord in dogs with a self-locking device of a resorbable polyglycolic based co-polymer--feasibility and long-term follow-up study.

BACKGROUND: New surgical techniques are developed to enable a quicker, easier and safer surgery with reduced risk of complications and shortened time needed for recovery. A resorbable device, a self-locking loop, was designed for surgical ligation. The objective of this pilot study was to investigate the feasibility of ligating the spermatic cord with the device, its biocompatibility and long-term resorption in dogs. RESULTS: The device was made of a block co-polymer (glycolide and trimethylene carbonate), manufactured by injection moulding and consisted of a flexible band running through a case with a locking mechanism. Ten devices were tested for ligation of the spermatic cords in five dogs admitted for routine neutering. The dogs were monitored by physical examination and ultrasonography of the site of ligation, area of spermatic cord and medial iliac lymph nodes regularly until no hyperechoic remnants of the device or acoustic shadowing or local tissue reactions were observed. Haemostasis of the spermatic cords was achieved with the devices. On ultrasonography the devices were seen as hyperechoic structures for 2 months after neutering causing acoustic shadowing for 1 month. The dogs were monitored for 3 - 5 months after surgery. Gradual decrease in echogenicity and final disappearance of the hyperechoic structures suggested resorption. Macroscopic and histological post mortem examinations were performed in one dog at 3 months after surgery. Post mortem examination showed a tissue reaction of a suture granuloma that was restricted in extent at site of the device. CONCLUSIONS: The results of this pilot study suggest biocompatibility and indicate that ligation of the spermatic cord is feasible with the device.

Reduction in pain suffered by lambs at castration.

The acute pain produced by bloodless castrators was studied by comparing the behavioural and plasma cortisol changes in groups (n=8) of 3-week-old Dorset cross lambs after castration with a 22 cm (9") Burdizzo, a new power assisted castrator and by a combined method using a Burdizzo and elastrator ring. The time spent in abnormal postures (52-58 min) and the peak cortisol response (110-120 mmol l(-1)) were similar for the three methods, although the powered castrator produced a more sustained response. The Burdizzo method halved the incidence of active behaviours compared with the powered castrator and combined methods (16 versus 30, 32 counts). Intratesticular local anaesthetic administered 2 min before the Burdizzo castrator and combined method, or intramuscular injection of the non-steroidal anti-inflammatory drug diclofenac, 20 min before the application of a Burdizzo, significantly reduced the peak plasma cortisol response to 80 nmol l(-1). Diclofenac also significantly reduced the time spent trembling or in abnormal postures.

[Analysis of silicone testicular implants after explantation]. / Analyse d'implants testiculaires en silicone après exérèse.

Two juvenile size silicone testicular prostheses were analyzed following replacement by adult size devices after 72 and 99 months in situ. Scanning electron microscopy and electron microprobe studies were carried out on the explanted silicone prostheses and their attached tissue capsules. The material at the surface of the prostheses gave no evidence of biodeterioration. However, localized sites of calcification were observed. The adjacent tissue capsule consisted of two distinct concentric layers with different morphologies; the one adjacent to the prosthesis consisted of dense arrays of collagen fibres oriented parallel to the silicone surface and extending outward to a thickness of 100-120 microns. The outer layer was less dense, more disordered and was uneven in thickness. It contained numerous discrete particles of silicon-rich material. Technical and clinical implications of these results are discussed.

Tissue-puncher and loop-ligation--new aids for surgical-therapeutic pelviscopy (laparoscopy) = endoscopic intraabdominal surgery.

The optimal development of the pelviscopic instruments for diagnostic purposes provides us with the start in the field of surgical therapeutic pelviscopy. Newly developed instruments: Loop ligation-applicator, Tissue-Puncher (morcellation-forceps), Aqua-Purator and the new CO2-PNEUS-AUTOMATIC (S = security) have enabled us to replace some of the prior operations requiring classic gynecologic laparotomy with surgical-therapeutic pelviscopy: Ovarectomy, adnectomy, myomectomy, cystectomy, resection of the tube-pregnancy. After more than 2,200 smaller surgical interventions were performed successfully since 1973 via pelviscopy with the hemostasis aided by 100 degrees C destructive heat (Endocoagulatory, Crocodile-Forceps and Point-Coagulator) more than 50 ovarectomies etc, could be performed in 1977 via pelviscopy without intra- or postoperative complications.