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Biomedical subjects

D Stephens

Publications and source records attributed to D Stephens.

At least 145 records · Page 8Linked to original sources

A prospective randomized trial of fluorouracil versus fluorouracil plus cisplatin in the treatment of metastatic colorectal cancer: a Hoosier Oncology Group trial.

From May 1984 through December 1986, 141 patients with metastatic adenocarcinoma of the colon or rectum were entered on this Hoosier Oncology Group (HOG) trial evaluating the role of cisplatin in systemic therapy. Patients were stratified by the presence or absence of hepatic metastases and by performance status, and were subsequently randomized to receive fluorouracil (5-FU) (15 mg/kg/wk) alone or the same dose of 5-FU plus cisplatin (60 mg/m2 every 3 weeks). The total duration of treatment was six cycles (18 weeks). In 132 fully evaluable patients the objective response rates were 19% for 5-FU and 22% for 5-FU plus cisplatin. Statistically, the median survival times of 40 and 39 weeks were not significantly different (P = .62). However, the median duration of remission (MDR) was superior (P = .05) for 5-FU alone. This study fails to confirm clinically significant synergy of 5-FU plus cisplatin in the treatment of metastatic colorectal cancer.

Adult↗

Computerized axial tomography as an aid in bite mark analysis: a case report.

A case is presented to demonstrate the use of computerized axial tomography (CAT) to develop precise registration of incisal edges for comparison to bite marks. Emphasis is drawn to the availability of CAT Scanning equipment and the importance of understanding its use as an adjunct or alternative to already accepted methods of incisal registration.

Bites and Stings↗

Effect of beta-adrenergic blockade on lipid mobilization induced by fasting in dogs.

To evaluate the contribution of catecholamines to the fasting-induced lipid mobilization prolonged or acute blockade of beta-adrenergic receptors with propranolol was applied in dogs during 72 hrs of food withdrawal. Propranolol given orally in a dose of 15 mg twice daily throughout the whole period of fasting failed to modify the increases in the plasma FFA and glycerol concentrations. The acute beta-adrenergic blockade due to i.v. injection of propranolol (0.5 mg/kg b.w.) caused marked decreases in the plasma glycerol concentration both in the dogs fasting for 24 h and 72 hrs, whereas the effects of propranolol on the plasma FFA concentration was found only in the early stage of fasting. Plasma catecholamine concentrations were enhanced significantly by the 72 hrs food withdrawal and neither prolonged nor acute propranolol administration modified significantly this effect. The fasting-induced decreases in the serum insulin concentration were more pronounced in dogs treated with propranolol. Results of this study indicate that catecholamines are involved in the control of lipolysis during short term starvation. However, under these conditions beta-adrenergic blockade did not impair FFA mobilization most probably due to an enhanced contribution of other hormones to the control of this process.

Adrenergic beta-Antagonists↗

Mechanism of sympathetic activation during prolonged physical exercise in dogs. The role of hepatic glucoreceptors.

It seems likely that depletion of body carbohydrates may account for the rise in the sympathetic activity during prolonged exercise, since glucose given during or before exercise reduces the increase in plasma catecholamines. The aim of the present study was to find out whether the increase in plasma noradrenaline (NA) in response to exercise can be reduced by 1. increasing of the amount of carbohydrate available for metabolism without producing hyperinsulinemia and 2. by inhibition of afferent activity from hepatic glucoreceptors. The study was performed on dogs which exercised whilst receiving either the intravenous fructose infusion (2.2 mmol/min) or a slow glucose infusion (0.25 mmol/min) which was given either via the portal or a peripheral vein. Fructose infusion reduced the muscle glycogen depletion during exercise and reduced the increase in plasma NA and glycerol concentrations without altering the blood glucose or insulin levels. The exercise-induced increases in plasma NA and glycerol concentrations were significantly smaller with intraportal than with peripheral glucose infusion but there were no differences between these two cases in the concentration of glucose in the systemic circulation. These findings indicate that the reduction of the plasma NA response to physical effort under conditions of increased carbohydrate availability cannot be attributed to the inhibitory effect of insulin on sympathetic activity and provide evidence for the participation of hepatic glucoreceptors in the control of the sympathetic activity during exercise.

Animals↗

Distribution of vasoactive intestinal peptide, bombesin, and gastrin-cholecystokinin like peptides in the avian intestinal tract and brain.

The distribution of vasoactive intestinal peptide (VIP), bombesin and gastrin-cholecystokinin in the chicken was studied by radioimmunoassay of tissue extracts. VIP was present in high concentrations in colon (186 +/- 29 pmol/g), cloaca (116 +/- 27 pmol/g), jejunum (97 +/- 14 pmol/g) and pancreas (15 +/- 3 pmol/g) but not detected in lung, liver or thymus. The highest concentration of bombesin was in the proventriculus (92 +/- 13 pmol/g), negligible in remaining gut but found in brain. Gel chromatography indicated two forms of bombesin: one form eluting with bombesin-14 and the other with gastrin releasing peptide. Gastrin-like immunoreactivity was found in low levels in the gut and brain. The concentrations were higher with an antiserum which cross reacted with the carboxy terminus common to gastrin-17 and CCK compared to a gastrin specific antisera (P less than 0.01). This suggests that the carboxy terminal region has been conserved during evolution. Each distribution pattern of bombesin, VIP and gastrin CCK is different, and distinct from that found in mammals, suggesting specific roles for these peptides in birds.

Animals↗