Biomedical subjects

A Kononov

Publications and source records attributed to A Kononov.

7 recordsLinked to original sources

PubMed1997

Fibrin-glue assisted vasoepididymostomy: a comparison to standard end-to-side microsurgical vasoepididymostomy in the rat model.

PURPOSE: The use of fibrin glue for vasovasostomy has produced high patency rates in animal models. Vasoepididymostomy is a microsurgical technique that might be made easier if fibrin glue could substitute for microsutures. We evaluated the efficacy of a new vasoepididymostomy technique using fibrin glue. MATERIALS AND METHODS: Bilateral vasoepididymostomies were performed in 24 male Sprague-Dawley rats using a conventional microsurgical technique on one side and a fibrin-glue assisted technique on the other. The rats were sacrificed 30 days after surgery and anastomotic patency was assessed by examining the vasal fluid for sperm, injecting methylene blue dye into the vas deferens and observing backflow into the epididymis by gross inspection and histological studies. Additionally, the incidence of granuloma formation was compared between the two techniques. RESULTS: Fibrin-glue anastomoses showed a patency rate of 79% (n = 19), compared with 63% (n = 15) for the conventional suture anastomoses (p = 0.29). Among the patent anastomoses, the incidence of sperm granuloma formation between the sutured (12, 50%) and the fibrin glue anastomoses (16, 67%) did not differ significantly (p = 0.36). Morphological tissue changes were similar for the two techniques. The time required for anastomosis using fibrin glue was significantly shorter than the conventional suture technique (p < 0.001). CONCLUSIONS: Conventional suturing techniques for vasoepididymostomy require advanced microsurgical skills. The use of fibrin glue simplifies this procedure and provides patency rates comparable to microsutured, end-to-side anastomoses.

Animals↗

PubMed1996

Fibrin glue-assisted end-to-side anastomosis of rat femoral vessels: comparison with conventional suture method.

Conventional methods of microvascular anastomosis using sutures cause vessel narrowing, foreign body reactions, and intravascular thrombosis. Although fibrin glue seems to be the ideal material to perform a microvascular anastomosis, its success has been limited. Excess fibrin used in some of the earlier methods has caused vessel narrowing and intravascular thrombosis. We evaluated the quality of end-to-side anastomosis using fibrin glue applied with a new technique and minimal sutures, and compared the results to those obtained with a standard suture technique. End-to-side anastomosis of femoral vessels was performed in 32 male Sprague-Dawley rats. Fibrin glue was topically applied at the anastomotic site, after inserting only two corner sutures. The fibrinogen component obtained from single donor human cryoprecipitate, was combined with bovine thrombin (500 IU per milliliter). In the control group (N = 16), the anastomosis was performed using eight to ten interrupted 10/0 nylon sutures. Fibrin glue-assisted anastomosis took less time, caused less bleeding at the anastomotic sites, and achieved a patency rate comparable to that provided by the suture technique. We have shown that a new, atraumatic technique of microvascular anastomosis with cryoprecipitate-thrombin glue and only two sutures, can produce excellent patency rates. This technique is easy to perform, inexpensive, and does not involve new equipment.

Anastomosis, Surgical↗

PubMed1996

Evaluation of nerve recovery from minimal-duration crush injury.

The recovery of damaged peripheral nerves has been the subject of multiple studies. The effects of an inadvertent clamping of a nerve has not been well examined. An experiment was performed to evaluate the effects of a minimal-duration crush injury on the rat sciatic nerve and to determine if walking track analysis was useful in evaluating the short-term functional deficit. Ten Sprague-Dawley rats underwent high-pressure, short-duration crush injuries. Walking track analysis was done regularly for 3 weeks. Histological specimens for light and electron microscopy were taken at postoperative days 3, 7, 14, 21, and 42 from similar animals. There was significant decrease in function by the second week, which then improved to control levels after week 3. Toluidine blue and electron microscopic findings confirmed the clinical course, while routine histological findings tended to lag behind the return of function. Walking track analysis appears to be an effective method of evaluating the short-duration nerve crush injury.

Animals↗

PubMed1995

Surgical anatomy of the celiac artery and portal vein of the rat.

The study of liver function and diseases requires detailed knowledge of the regional anatomy of and surgical approach to the vascular supply of the liver. The objective of this study was to systematically describe the regional anatomy of the circulation to the rat liver to facilitate the planning and performance of future studies of the liver in this animal. Twelve adult rats underwent general anesthesia and vivisection of the celiac axis and portal vein using an operating microscope. The major vessels of these vascular systems were evaluated for their origin, course, relationship with neighboring structures, diameter, and length. All vessels were easily visualized by a ventral approach after mobilization of the intermediate lobe of the liver and its papillary process. The origin and course of the major vessels are similar to those of humans, and variability in vessel origin was identified in this small number of animals. Median vessel diameters were between 0.5 and 1 mm (range, 0.25 to 1 mm) for the celiac artery and its branches, and 3 mm for the portal vein (range, 2 to 3 mm). Median vessel length was between 3 and 7 mm (range, 2 to 8 mm) for the celiac artery and its branches, and 7 mm for the portal vein (range, 4 to 8 mm). The anatomic description obtained in this study is important for the appropriate selection of vessels for cannulation or ligation during study design, as well as vessel isolation during performance of the study. The diameter and length of vessels are important in the selection of appropriately sized catheters and perivascular devices.

Animals↗

PubMed1994

Continuous rat intravenous infusion.

Hypovolemic shock and ischemic injury to the graft commonly cause death in small animals after organ transplantation. A venous line must be readily available to replace fluids before fatal complications occur. To establish a venous line, researchers expose a vein by preliminary surgery. This time-consuming procedure adds unnecessary trauma to the recipient and worsens the results. The possibility of long-term fluid transfusion in small animals by serial injections at close intervals is quite limited. We describe a simple technique of continuous i.v. infusion by catheterization of the rat dorsal penile vein with a 24-gauge, 3/4-inch catheter. This easy-to-learn technique has permitted us to establish a venous line quickly without trauma in 148 rats while doing donor and recipient procedures for small bowel and ileocecal segment transplantation. The technique we describe has eliminated one of the most frequent causes of postoperative mortality after organ transplantation-hypovolemic shock. We would like to emphasize that other measures, including avoiding massive bleeding and reducing operative and warm ischemic time, are also very important in preventing this complication. The massive i.v. infusion alone may not totally eliminate hypovolemic shock if other factors are neglected. The use of this technique has allowed us to perform small bowel transplantation with 90% success.

Animals↗

PubMed1994

Two metric solutions to three-dimensional reconstruction for an eye in pure rotations.

A problem in space perception concerns how a mobile observer acquires information about the structure of objects. Earlier research derived the optic-flow equations for an eye undergoing pure rotations. It was suggested that, by utilizing three points and two views, one can recover the distance of points and the motion parameters. The radius of the eyeball was the metric unit. Yet the common view regards this problem as indeterminate. We derived a unique solution in the discrete case, which required three points and two views. However, when we observed a single bright point, a substantial amount of visual stability existed. We therefore derived a solution in the differential approach for a single point, which is based on a distinction that we made between mathematical and visual points. Both solutions were checked with a computer simulation and were found to be accurate, supporting the space perception in navigation (SPIN) theory.

Computer Simulation↗

PubMed1993

A simple arteriotomy method for microsurgical end-to-side anastomoses: technical aspects of use in training and laboratory applications.

An experiment was carried out to show the patency rates of microsurgical carotid artery bypasses with femoral artery grafts, using a single-cut arteriotomy in rats. A bypass was done on 127 Sprague-Dawley rats. Of these, 125 were patent after 20 min, and all of these were patent after the animals were sacrificed at 3 days, for a 98 percent patency rate. The method of performing the arteriotomies, as well as the bypass itself, is described. The benefits of using the end-to-side anastomosis are explained. The authors conclude that the single-cut arteriotomy is convenient and easy to perform. The end-to-side anastomosis is a worthwhile technique and should encourage the proficiency of every student of microsurgery.

Anastomosis, Surgical↗