Analysis of sphingosine 1-phosphate receptors involved in constriction of isolated cerebral arteries with receptor null mice and pharmacological tools.

BACKGROUND AND PURPOSE: Sphingosine 1-phosphate (S1P) selectively and potently constricts isolated cerebral arteries, but this response has not been pharmacologically characterized. EXPERIMENTAL APPROACH: The receptor subtype(s) involved in S1P-induced cerebrovascular constriction were characterized using genetic (S1P(2) and S1P(3) receptor null mice) and pharmacological tools (phospho-FTY720, a S1P(1/3/4/5) receptor agonist; SEW2871, a S1P(1) receptor agonist, JTE-013, a S1P(2) receptor antagonist, VPC23019, a S1P(1/3) receptor antagonist). Isolated basilar or peripheral (femoral, mesenteric resistance) arteries, from either rat or mouse, were studied in a wire myograph. KEY RESULTS: S1P concentration-dependently constricted basilar artery in rat, wild-type (WT) and S1P(2) null mice, but barely affected vascular tone in S1P(3) null mice. Vasoconstriction to U46619 (a thromboxane analogue) or to endothelin-1 did not differ between WT, S1P(2) and S1P(3) null mice. JTE-013 inhibited not only S1P-induced vasoconstriction, but also KCl-, U46619- and endothelin-1-induced constriction. This effect was observed in WT as well as in S1P(2) null mice. VPC23019 increased the concentration-dependent vasoconstriction to S1P in both rat and mouse basilar arteries with intact endothelium, but not in rat basilar artery without endothelium. Phospho-FTY720 concentration-dependently constricted rat basilar arteries, but not femoral or mesenteric resistance arteries, while SEW2871 did not induce any response in the same arteries. CONCLUSIONS AND IMPLICATIONS: S1P constricts cerebral arteries through S1P(3) receptors. The purported S1P(2) receptor antagonist JTE-013 does not appear to be selective, at least in rodents. Enhancement of S1P-induced contraction by VPC23019 might be related to blockade of S1P(1) receptors and NO generation.

The effect of the anastomotic size on gastric emptying after hemigastrectomy with Billroth II reconstruction.

OBJECTIVE: To determine if the size of the gastrojejunal anastomosis after Billroth II reconstruction was the rate-limiting factor in gastric emptying in the postoperative period. METHODS: Twelve mongrel dogs were randomized to have either 1.5 cm or 5 cm gastrojejunal anastomoses prior to Billroth II hemigastrectomy. Each dog had three solid and three liquid radiolabelled emptying studies pre- and postoperatively. Data were collected using a gamma camera. For liquid studies, images were obtained at 0 min, 2 min, 4 min, 6 min, 8 min, 10 min, 20 min, 30 min, 40 min, 50 min and 60 min. For solid studies, images were obtained at 0 min, 5 min, 10 min, 20 min, 30 min, 40 min, 50 min, 60 min, 70 min, 80 min, 90 min, 100 min, 110 min and 120 min. Means were compared by analysis of variance using the repeated measures option. RESULTS: Postoperative liquid emptying was significantly faster in the first 10 min with both 1.5 cm and 5 cm anastomoses compared with preoperative scans in the same animals (45% versus 20% and 48% versus 29%, respectively). On the other hand, solid gastric emptying was much slower postoperatively with the 1.5 cm anastomosis compared with preoperative scans (29% versus 65%) as well as compared with postoperative 5 cm anastomosis (29% versus 62%) at the end of 120 min. CONCLUSIONS: Our model suggests that the gastric emptying of solids is affected by the size of the gastrojejunal anastomosis and not by the diameter of the efferent limb of the small intestine following Billroth II reconstruction.

Groin lymphatic complications after arterial reconstruction.

PURPOSE: The purpose of this study was to better define the associated risks and optimal management of groin lymphatic complications (GLC) after femoral artery reconstructive operations. METHODS: Retrospective review of a vascular surgery registry for the last 15 years identified 2679 arterial operations requiring a groin incision. Forty-one GLC were recognized, 28 lymphocutaneous fistulas (LF) and 13 lymphoceles. RESULTS: The incidence of GLC was 1.5% per patient or 1.2% per incision. The highest incidence of GLC was in patients having an aortobifemoral bypass for aneurysmal disease in a previously operated groin (8.1% per patient) and in those undergoing an isolated femoral procedure in a previously operated groin (5.3%). The lowest frequency of GLC was after femoropopliteal/tibial bypasses (0.5%). Twenty-nine patients (71%) were treated without operation with bedrest, intravenous antibiotics, and aggressive local wound care. Operative therapy with wound reexploration attempted identification and control of the leak site, and meticulous wound closure was used in 12 patients (29%). Lymph fistulas in patients undergoing reoperation (10/28) resolved sooner than in patients treated without operation (18/28) (9 +/- 3 days vs 24 +/- 3 days). Infectious wound complications with one resultant graft infection developed in five of 18 patients with LF who did not undergo reoperation. There were no wound or graft infections in the patients in the LF group treated with operation. Operative exploration of lymphoceles did not reduce hospital stay or infectious wound complications. Repetitive lymphocele aspiration did not affect rapidity of resolution or increase the infectious complications. CONCLUSION: GLC remain a troublesome complication of femoral arterial reconstruction. Early reoperation should be performed once a LF is diagnosed. Treatment for lymphoceles should be individualized, with neither operative nor nonoperative management showing clear superiority.

Industrial accidents at a bauxite mining community Linden, Guyana - abstract

The objectives of this prospective, 4-month study were to determine the incidence and types of injuries at Guymine (a bauxite mining company) and evaluate the factors which predispose to injuries at the work site. From June 1 to September 30, 1991, 86.5 percent (77) of all full-time employees referred for involvement in an industrial accident were seen by one of the investigators and information on the injury was collected, using a designed questionaire. There were 69 males and 8 females and most of the injured were in the age ranges 20-24 and 35-44 years. The incidence rate (IR) in males was 29.5/1,000 and 8/1,000 in females. The IR was highest in labourers (220/1,000), increased with increasing work experience and was highest in the mines (58.4/1,000). Most accidents occurred during the day-light hours and injuries most frequently involved the hands and fingers. Hazardous practices by workers and defective agencies were the main predisposing factors. Forty-four point four per cent of work sites were in a poor condition. About one year of work time was lost due to injuries during the study (AU)

Open laparoscopy for laparoscopic cholecystectomy.

This report deals with the first 350 laparoscopic cholecystectomies performed at Creighton University, beginning in October 1989, by one of the authors (R.J.F., Jr.). An open technique was used for initial access to the abdominal cavity in 343 patients (98%). Patients included 274 females and 76 males, with an average age of 45.5 years. Weight ranged from 72 to 316 pounds (32-142.2 kg). The laparoscopic procedure was successfully completed in 338 (96.6%). Operative cholangiography was performed in 113 (32.3%), and 52 (14.7%) had acute cholecystitis as determined by the final pathological report. Median operating time was 80 min. There was no operative mortality. Bile duct injury was not seen. Postoperative complications occurred in 21 patients (6%), only two of which were directly related to the open technique (cellulitis of the umbilical wound requiring antibiotics). A third patient (0.3% of 343 successful laparoscopies) required reoperation on postoperative day 4 for a small bowel perforation; the exact cause could not be determined, but conceivably it was related to the umbilical minilaparotomy. We conclude that the open technique is safe and effective method for initial peritoneal access prior to laparoscopic cholecystectomy.

Extension of renal cell carcinoma into the vena cava with concomitant coronary artery disease: surgical considerations.

Surgical removal of renal cell carcinoma with extension into the inferior vena cava can be a difficult operation. Cardiopulmonary bypass and circulatory arrest have been used to assist in resection of tumors that extend into the vena cava above the level of the hepatic veins. Coronary artery disease is a common problem and may present together with renal cell tumors. A patient with left main coronary artery disease and a renal cell carcinoma extending into the vena cava provides a management challenge. We present such a case and discuss the surgical options.

The prevention of cholelithiasis with infused sodium chenodeoxycholate in the prairie dog (Cynomys ludovicianus).

1. This study examines the efficacy of infused sodium chenodeoxycholate to prevent cholesterol gallstone formation in the prairie dog when fed a high cholesterol diet. 2. Three experimental groups were designed to examine this. The first group (N = 5) was fed a normal rat chow diet, the second group (N = 5) was fed a high cholesterol diet (0.4% cholesterol by weight), and the third group (N = 5) was fed a high cholesterol diet plus given a daily injection of intravenous sodium chenodeoxycholate (15 mg/kg). 3. All of the animals in the second group had cholesterol crystals and cholesterol gallstones. In the third group, none of the animals had gallstones, and all but one lacked cholesterol crystals. 4. Statistical analysis showed that the first and third groups were statistically identical in their lithogenic indices and biliary lipid composition. 5. We concluded that infused sodium chenodeoxycholate is effective in preventing cholesterol gallstone formation in the prairie dog when fed a high cholesterol diet.