Biomedical subjects

A M Ress

Publications and source records attributed to A M Ress.

8 recordsLinked to original sources

PubMed1998

Nerve regeneration in diabetic rats.

This study evaluated the capacity of diabetic rats to recover the ability to walk after nerve repair or nerve graft of the posterior tibial nerve at thigh level. Functional recovery of the posterior tibial nerve was evaluated by walking track analysis during regeneration in streptozotocin-induced diabetic rats. Surgical procedures were performed 8 weeks after induction of diabetes. The nerve repair was epineurial. The nerve graft was a 1.5 cm segment orthotopically replaced. There was no significant difference in functional recovery between normal and diabetic rats for both the nerve repair and nerve graft groups at 6, 12, and 24 weeks after nerve reconstruction. It is concluded that the presence of diabetes is not a contraindication for nerve reconstruction.

Animals↗

PubMed1998

Finger polydactyly.

Polydactyly is one of the most common congenital differences. Duplications of the index finger, central rays, and small digit each have unique characteristics and associations. Complex anomalies such as the mirror hand and pentadactyly represent specialized forms of polydactyly. The goal of reconstructing a functional hand is met by appreciating the anatomic variations and systemic implications, then employing the challenging technical and intellectual concepts described.

Fingers↗

PubMed1995

Preoperative highly selective catheter localization of occult small-intestinal hemorrhage with methylene blue dye.

In patients with occult lower gastrointestinal bleeding, locating of the source of the hemorrhage can be quite difficult. While multiple diagnostic tests may confirm a small bowel source of bleeding, precise localization allowing a directed, conservative surgical resection may be problematic. We describe three patients each of whom presented with hemorrhage from the small intestine. The preoperative use of highly selective angiographic catheter placement combined with intraoperative methylene blue dye injection allowed us to precisely locate the source of hemorrhage and to resect a conservative length of small intestine. This technique has been successful in the three patients herein, and we believe that it should be included in the options available to the surgeon.

Adult↗

PubMed1995

Free radical damage in acute nerve compression.

Nerve compression causes injury by local ischemia and direct mechanical distortion. Peripheral nerves in diabetes mellitus are more prone to injury than those of nondiabetics. We sought to determine whether reperfusion-induced, oxygen-derived free radical injury occurs in peripheral nerves subjected to acute compression in normal and chronically diabetic rats. Female Sprague-Dawley rats weighing 250 to 275 g (N = 347) were divided into two groups: normal and streptozocin-induced diabetics. A total of 187 normal and 160 diabetic nerves were analyzed. After 8 weeks of untreated hyperglycemia, the sciatic nerves of normal and diabetes mellitus rats were subjected to one of three operations: a sham operation, 24-hour compression alone, and 24-hour compression followed by 1-hour reperfusion (CR). Nerve compression was established by banding the right sciatic nerve with a Silastic tubing, 1 cm long and 0.62 mm internal diameter, which was secured with 6-0 nylon suture. In the CR group, after 24 hours of compression, the tubings were released for 1 hour to permit reperfusion. Nerve tissue within the zone of compression underwent biopsy examination and was frozen for subsequent analysis. Blood flow to the nerve was quantified by injecting fluorescein (10 mg/kg intravenously) 10 minutes before harvest and measuring tissue levels fluorometrically. Compression with the Silastic tubing significantly reduced neural blood flow by 75%. Blood flow improved but failed to return to baseline levels after tubing release in diabetes mellitus nerves while perfusion returned to baseline in non-diabetes mellitus nerves. Nerve homogenate was assayed for malonyldialdehyde, an indicator of lipoperoxidation, as well as enzymes of cellular defense and glucose metabolism.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1995

Effects of tissue expansion on secondary ischemic tolerance in experimental free flaps.

The effects of tissue expansion on free flap tolerance and metabolic response to secondary ischemia were evaluated. A total of 178 male syngeneic Lewis rats were used: 28 in perfusion study and 75 donor and 75 recipient animals in flap survival study. Animals were organized in three experimental groups: control, sham operation, and expansion group. Sham group animals had the expander implanted but not insufflated. After 4 weeks of tissue expansion, 3 x 5-cm epigastric free flaps were transplanted to recipient animals. Twenty-four hours later, secondary ischemia was produced by 3-hour venous occlusion. Flap survival, perfusion, and enzyme activities were determined. Pre-expanded skin flaps had an increase in perfusion of approximately 700% as measured by fluorescein levels compared with control flaps (p < 0.001) and demonstrated a better success rate (76%) compared with those of the control (40%) (p < 0.05) and sham (28%) groups (p < 0.05). Glutathione peroxidase, glutathione reductase, and glucose 6-phosphate dehydrogenase of the antioxidant defense systems significantly increased in skin in both the sham and the expansion groups. In response to secondary ischemia, the control and sham groups exhibited a decrease in enzyme activities of the glutathione redox cycle, whereas the expansion group showed no significant changes from the elevated baseline activities. Tissue expansion improved flap tolerance to secondary ischemia by increasing flap circulation and probably by augmenting tissue metabolic response to oxidative stress.

Animals↗

PubMed1994

Age and tolerance to secondary ischemia in rat epigastric flaps.

The use of microvascular procedures is increasing as the population continues to age. The purpose of this study was to observe the survival of skin flaps after ischemic injury. Skin flaps (n = 50) underwent either 3 hours of primary (1 degree) or secondary (2 degrees) venous occlusion in young (2-3 mo) and old (18-22 mo) rats. Skin flap survival was assessed on postoperative day 7. Survival rates for young and old after 3 hours of 1 degree ischemia was 100% and 90% (ns). Survival rats for young and old after 2 degrees ischemia were 67% and 47% (ns).

Aging↗

PubMed1993

Spectrum and management of major complications of laparoscopic cholecystectomy.

Laparoscopic cholecystectomy has become the most prevalent method of treating uncomplicated, symptomatic cholelithiasis in the United States and elsewhere. As experience with this procedure grows, certain pitfalls are becoming apparent. Since October 1990, we have treated 22 patients for major injuries incurred during laparoscopic cholecystectomy, including 15 women and 7 men (range: 23 to 85 years). One patient had previous upper abdominal surgery; no other patient had any relative contraindication to laparoscopic surgery. The most frequent site of injury (19 patients) was the extrahepatic biliary tract. There was one fatal duodenal perforation. All but two patients whose injuries went unrecognized at laparoscopy were symptomatic during the immediate postoperative period. The biliary injuries included complete transection of the common hepatic or common bile duct in 10 patients, complete ductal occlusion in 3, a cystic duct stump leak in 2, and a partially retained gallbladder with a contained intraperitoneal bile leak in 2. The site and extent of biliary injuries were delineated with transhepatic or endoscopic retrograde cholangiography. Reconstruction or repair of the biliary tract was accomplished with Roux-en-Y hepaticojejunostomy or cholangiojejunostomy in 11 and 1 patients, respectively, completion cholecystectomy in 2, and temporary transhepatic stenting, primary choledochocholedochostomy, and primary choledochorrhaphy over a T-tube in 1 patient each. One patient with a cystic duct stump leak was managed successfully with endoscopic sphincterotomy, whereas another required operative ligation. Laparoscopic injuries during cholecystectomy can lead to serious morbidity and mortality, thus emphasizing the need for adequate training and credentialing for surgeons and for a heightened clinical awareness of the potential complications, their long-term sequelae, and how to avoid them.

Adult↗

PubMed1992

Efficacy of intraoperative enteroscopy in diagnosis and prevention of recurrent, occult gastrointestinal bleeding.

The role and effectiveness of intraoperative enteroscopy in the evaluation of gastrointestinal (GI) bleeding of obscure origin is not clearly defined. Our aim was to determine if intraoperative enteroscopy is effective in identifying a source, which would lead to therapy and prevent recurrent gastrointestinal hemorrhage. Forty-four patients (median age: 64 years) underwent intraoperative enteroscopy. Median number of preoperative blood transfusions, duration of bleeding (months), and prior hospitalizations for GI hemorrhage were 19, 15, and 2, respectively. Many patients had risk factors associated with bleeding. All had undergone an extensive preoperative evaluation. Intraoperative enteroscopy was completely negative in 13 (30%). A site-specific source was seen in the small bowel in 31 patients (70%); 27 patients had lesions amenable to segmental resection with or without other means of definitive management. Only 6 of 31 patients (19%) had lesions that were actively bleeding. Twenty-three (52%) patients have had recurrent bleeding requiring transfusion (median follow-up: 21 months). Although intraoperative enteroscopy identified specific mucosal abnormalities in 70% of patients, the therapeutic efficacy in preventing recurrent hemorrhage was only 41%. Intraoperative enteroscopy is an effective tool in selected patients with occult GI bleeding and correctly identifies a treatable source and prevents recurrent bleeding in 41% of patients.

Endoscopy, Gastrointestinal↗