Biomedical subjects

I S Benjamin

Publications and source records attributed to I S Benjamin.

130 records · Page 8Linked to original sources

PubMedDate not supplied

Nutritional risk factors in major hepatobiliary surgery.

Preoperative nutritional assessment was performed for 32 patients undergoing surgery for malignant hepatobiliary and pancreatic disease. Weight, mid-arm circumference, total body potassium (TBK), and skin test reactivity were significantly reduced in the seven patients who died after operation (p less than .05, Student's t-test and Fisher's exact test). Analyses of major life-threatening complications indicated that those who had a complicated postoperative course (17 patients) had a significantly lower TBK (p less than .05, Fisher's exact test). Using linear discriminant analysis (SPSS computer program), correct prediction of postoperative death or survival was possible in 85% of patients if measured by TBK alone, and in 83% if weight loss and serum albumin were used. Seventy three percent were correctly classified as complicated or uncomplicated by TBK alone, but serum albumin and weight loss were not helpful in predicting patients with complications. This study shows that malnutrition and operative risk may be identified preoperatively in patients with malignant hepatobiliary and pancreatic disease. Objective improvement may be achieved by intensive nutritional support.

Adenocarcinoma↗

PubMedDate not supplied

Pyridoxalphosphate-6-azophenyl-2',4'-disulphonic acid (PPADS) as a tool for differentiation of P2Y2-receptor-mediated vasorelaxation in guinea pig aorta.

The action of the putative P2Y1-receptor antagonist pyridoxalphosphate-6-azophenyl-2',4'-disulphonic acid (PPADS) was studied in guinea pig aorta for potential use in the differentiation between P2Y1 and P2Y2 purine receptors. Concentration-effect curves to 2-methylthioadenosine triphosphate (2MeSATP) and uridine triphosphate (UTP), agonists at P2Y1- and P2Y2-receptor sites, respectively, and the common agonist adenosine triphosphate (ATP) were constructed in guinea pig aortic ring preparations with the tone raised by 5 microM of noradrenaline. A ranked order of agonist potency of 2MeSATP > ATP > UTP resulted from the construction of concentration response curves to vasorelaxation of the agonists. Deendothelialization virtually abolished vasorelaxation to UTP but made no significant difference to 2MeSATP-induced responses. PPADS exhibited noncompetitive inhibition at P2Y1-receptor sites by reducing the maximal response to 2MeSATP, although a trend towards a right shift of the concentration-effect curves was observed. In total contrast, PPADS enhanced P2Y2-mediated vasorelaxation to UTP by shifting the concentration-effect curves to the left and increasing maximal responses. Thus, PPADS is a noncompetitive antagonist at P2Y1 receptors but enhances responses, at least to UTP, at P2Y2 receptors in guinea pig aorta via a hitherto unknown mechanism. Thus, PPADS is a potentially useful substance that may be used for differentiation between P2Y1 and P2Y2 receptors in the guinea pig aorta.

Adenosine Triphosphate↗

PubMedDate not supplied

Early systemic hypertension after surgical closure of atrial septal defect.

The systemic haemodynamic changes occurring in the immediate post-operative period were examined in a series of patients undergoing closure of atrial septal defect (A.S.D.) and in a consecutive series of all patients undergoing open-heart surgery in this Unit. Significant systemic hypertension was observed in 47.5% of patients in the A.S.D. series. In an attempt to explain this finding, several other haemodynamic variables were examined in relation to the systemic blood pressure. There was no correlation between central venous pressure or blood loss and systemic blood pressure. However, there was an inverse correlation between blood balance and systolic and diastolic blood pressure at 4 hours after operation. The explantation of this finding is unclear but it may be due to the effects on atrial receptors of lower right atrial and pulmonary artery pressures following closure of the A.S.D. Although the post-operative systemic hypertension was transient in most cases, it may produce adverse effects in the early post-operative period and therefore treatment with hypotensive agents should be considered in severe cases.

Blood Volume↗

PubMedDate not supplied

Antibiotic prophylaxis for biliary tract surgery: selection of patient and agent.

One hundred and three patients undergoing biliary surgery have been entered in a randomized prospective trial for antibiotic prophylaxis. Fifty six received piperacillin (2 gr) and 47 tobramycin (100 mg). Cultures were taken from bile at operation and a clinical and microbiological assessment for infection was carried out postoperatively. Overall infection rate was significantly lower in the piperacillin group (P less than 0.05). The positive bile culture and wound infection rates were also lower in the piperacillin group, though this did not reach statistical significance. Anaerobic bacteria (three patients) and Streptococcus faecalis (one patient) were isolated in the tobramycin group. Overall postoperative infection rate was similar in patients with risk factors for infection and in those without. In conclusion, piperacillin did not significantly improve bile and wound infection rates compared to tobramycin. However piperacillin showed a more appropriate spectrum of activity. Antibiotic prophylaxis is suggested for all patients undergoing biliary surgery.

Bile↗