Early failure of expanded polytetrafluoroethylene in femoral vein replacement.

Grafts of expanded 30-mu fibril length polytetrafluoroethylene (PTFE) were inserted as segmental femoral vein replacements in nine dogs. The contralateral femoral vein served as a control, receiving a graft from each dog's right external jugular vein. Graft patency was monitored for 24 weeks postoperatively with serial venograms and venous pressures of the operated limbs. All expanded PTFE grafts and one autogenous graft thrombosed within 24 to 48 hours. Significant venous hypertension in the extremities receiving the PTFE grafts persisted for six months.

Effect of staphylococcal enterotoxin B on cardiorenal functions in rhesus macaques.

Selected cardiovascular and renal functions were measured for 5 hours in conscious, chair-restrained, female rhesus macaques (Macaca mulatta) after IV (0.05 and 1.0 mg/kg) or oral (1.0 mg/kg) administration of staphylococcal enterotoxin B (SEB). Cardiovascular functions, renal hemodynamics, and renal metabolism were also studied between 6 and 11 hours after IV SEB inoculation. Oral SEB produced few changes in cardiorenal functions. In contrast, IV SEB produced hypotension, tachycardia, increased total peripheral and renal vascular resistance, and decreased cardiac and renal functions. The early significant (P less than 0.05) renal depression was not associated with hypotension (mean arterial blood pressure greater than 100 mm of Hg). However, all measured renal functions except extraction ratio of PAH were positively correlated with decreased blood pressure (r = 0.52 - 0.71) in the later phase of SEB toxemia. It is concluded that the kidney is one of the organs affected by IV SEB. Renal impairment may partially contribute to death during SEB enterotoxemia in macaques.

Cardiovascular and hepatic responses of rhesus macaques to staphylococcal enterotoxin B.

Certain cardiovascular and hepatic functions were measured for a period of 6 to 14 hours in conscious, chaired, male rhesus macaques given (intravenously (IV) or orally) staphylococcal enterotoxin B (SEB). In macaques orally given SEB (1 mg/kg), there was little change in the cardiovascular variables. The half-life of injected indocyanine green was apparently prolonged in macaques given SEB as compared with that in the controls. However, in macaques given SEB (0.05 or 1.0 mg/kg) by IV injection, there were tachycardia, increase in arterial resistance, and decreases in blood pressure, cardiac output, stroke volume, cardiac work, mean cardiac power, and central blood volume. In addition, mean transit time from caudal vena cava to ascending aorta was prolonged and a simultaneous reduction of hepatic removal of indocyanine green occurred.

Portal and peripheral vein insulin responses to intravenous glucose in the rhesus monkey.

Catheterization of the portal vein and bilateral femoral veins were performed under general anesthesia in 6 healthy male rhesus monkeys. Four days later, sequential, simultaneous peripheral and portal plasma samples were obtained for glucose and immunoreactive insulin determinations before and after administration of 0.5 Gm. of glucose per kilogram (over a 1-minute period) via the opposite peripheral catheter. Two phases of insulin secretion were noted in both portal and peripheral plasma samples. An immediate early-phase insulin response was noted with a peak response at 1 minute followed by a rapid decline to a nadir at 5 minutes. A second phase of insulin secretion was evident with a peak response at 10 minutes and a subsequent decline to basal levels by 60 minutes. Simultaneous portal vein and peripheral vein glucose concentrations were not significantly different from each other by paired analysis. Thus, in the rhesus monkey peripheral insulin concentrations following intravenous glucose exhibit a biphasic response closely paralleling pancreatic insulin secretion.

Technique for portal catheterization in rhesus monkeys (Macaca mulatta).

A technique was developed for catheterization of the portal vein in rhesus monkeys (Macaca mulatta). Silicone rubber catheters (0.040 ID by 0.085 inch OD, or 0.030 ID by 0.065 inch OD) were surgically placed into the portal vein via the umbilical, inferior mesenteric, right colic, or ileocolic veins. The right colic and ileocolic veins proved to be the preferred route for catheterization. Both single end-hole and multiple end-hole catheters with 2 side holes were used. Catheter function was dependent upon proper placement within the portal vein and on maintaining patency. Single-hole catheters were successfully maintained by periodic flushing (2-3 times daily) with heparinized saline solution (1.5-4.0 units/ml), and multiple-hole catheters were best maintained by a continuous flow (1-2 ml/hour) of heparinized saline solution (1.5 units/ml). No adverse clinical effects due to the portal catheter were observed in any of the monkeys catheterized. The technique allowed placing the monkey in a restraint chair, thus enabling one to utilize the monkey in a conscious state.

Oral fructose tolerance, gastric emptying and absorption: a compartmental model.

Gastric emptying and intestinal absorption regulate transfer of ingested fructose from stomach to plasma. Using conscious rhesus monkeys we have developed a compartmental model which describes this system. Fructose tolerance tests were performed in groups of monkeys by intragastrically administering 2 g/kg of 10.5% D-fructose solution; fructose concentration in arterial plasma, [fructose], and intragastric volume were measured at intervals afterward. One group was pretreated with atropine; stomachs imptied with a time constant, tau, of 67 min. Another group received fructose solution with trisodium citrate added; tau was 18 min. Another group received only fructose; tau was 30 min. Using these constants, a model was developed to describe the [fructose] data. In this model k1 related amount of fructose in intestine to absorption rate and Ae represented absorption efficiency. K1 = 0.03 and Ae = 89% provided a good fit for data from the atropinized group. k1 = 0.018 and Ae = 56% provided a good fit for data from the other groups. Differences were explained by considering effects of atropine on gastrointestinal secretion. The model adequately describes our [fructose] data and may be adapted for tests utilizing other substances.

Effect of staphylococcal enterotoxin B on body fluid compartments in conscious rhesus monkeys.

Techniques for measuring changes in body fluid compartments after SEB injection i.v. in conscious rhesus monkeys are described and compared with base line values measured by identical techniques in normal monkeys. Although few changes were observed in body fluid volumes 3 h after i.v. staphylococcal enterotoxin B (SEB; 1 mg/kg), the F cell ratio and all fluid compartments except for RBC volume were decreased significantly by 5 h after i.v. SEB administration. Rapid intracellular dehydration and decreases in plasma and blood volumes appear to play a role in the development of circulatory shock during enterotoxemia in monkeys.