Biomedical subjects
Publications and source records attributed to J Morin.
The use of a Fogarty catheter instead of a silk suture in performing an endoscopic gastrostomy offers several advantages. It avoids the problems of stomach deflation, the stomach slipping off the intravenous cannula, the troublesome passage of a soft suture through a small caliber tube and grasping a soft mobile object in the stomach.
Autoradiographic studies were conducted to identify and characterize target cells for 1,25(OH)2 vitamin D3 in the pyloric region of rats and mice. After injection of 3H 1,25(OH)2 vitamin D3, nuclear concentration of radioactivity was observed in nuclei of duodenal epithelium and certain cells of pyloric glands, while most of the epithelial cells in the pyloric and gastric glands did not show nuclear labeling. In combined immunohistochemical studies, cells in the pyloric glands that showed nuclear concentration of radioactivity, were stained in their cytoplasm with antibodies to gastrin. Also, cells of the pyloric sphincter muscle showed nuclear labeling, in contrast to cells of the duodenal muscularis, which remained unlabeled under the conditions of the experiments. The results indicate that the cells with nuclear radioactivity contain receptors for 1,25(OH)2 vitamin D3 and suggest that gastrin secretion and pyloric muscle functions are regulated by a direct action of 1,25(OH)2 vitamin D3 on these cells.
Metabolic and hormonal responses to the administration of a gastric load of glucose (2.4 mg/g body wt) were evaluated after a fast of 6-7 h in unrestrained rats bearing a portal vein catheter. For the purpose of this study, we have designed a new technique for a direct catheterization of the portal vein that allows serial blood sampling in unrestrained Wistar rats. On the 6th postoperative day, food intake, body weight gain, liver function, histology of the liver, pancreas, intestine, and splanchnic blood flows were similar to those of sham-operated control rats. In the basal state glucose turnover was 21.3 +/- 0.9 mg.kg-1.min-1. After glucose ingestion, a portoperipheral gradient of lactate was present, reflecting the production of lactate by the intestine. Insulin secretion was biphasic and peaked at 12 min (344 +/- 46 microU/ml), whereas portal glucagonemia (400-500 pg/ml) remained unchanged. Sixty minutes after gastric glucose administration, 50% of the load was delivered at the periphery, and glucose utilization was increased by 100%. Hepatic glucose production decreased after 20 min and was inhibited by 30% at 60 min. Liver glycogen concentration remained unchanged during the experiment despite a normal capacity for glycogen synthesis.
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An experimental study was conducted in the rat to evaluate the sensitivity of the liver to hyperthermia and ischemia. A 15-min asanguineous isolated hyperthermic in vivo perfusion of the liver was done in rats with a normal liver and in rats with an hepatocarcinoma induced by chronic 3'-diethylaminoazobenzene intoxication. The perfusion was made using various ranges of temperature of the perfusate. In normal rats, the in vivo perfusion was well tolerated as long as the mean intrahepatic temperature remained under 38 degrees C. Postoperative evolution of serum transaminase level was similar whatever the temperature of the perfusate. Histological lesions of the hepatic parenchyma were as severe as the temperature of the perfusate was elevated. In rats with tumors, the mortality rate was elevated in the animals with large tumors. A moderate decrease in the serum alpha-fetoprotein level was observed during the first days after liver perfusion. In all cases, death occurred apparently as a direct consequence of liver injury. This study defines the sensitivity of the normal or neoplastic rat liver to hyperthermia and ischemia using a model of isolated in vivo perfusion of the liver. It provides a basis for further investigations on the effect of hyperthermia on experimental liver tumors.
The objectives of this study were to investigate the bactericidal activity in serum of cefotaxime alone or in combination with tobramycin against clinical strains and to determine the influence of tobramycin on the pharmacokinetics of cefotaxime. The peak bactericidal activity in serum of cefotaxime alone against Klebsiella oxytoca, Enterobacter aerogenes, Serratia marcescens, Pseudomonas cepacia, and Listeria monocytogenes varied between 1:4 and 1:256. Bactericidal activity could still be detected at 6 h against K. oxytoca and L. monocytogenes. The addition of tobramycin increased the bactericidal activity of cefotaxime against E. aerogenes from 1:16 to 1:128 (P less than 0.01). Cefotaxime recovery from urine was significantly decreased when tobramycin was added. Our data are comparable with those of other investigators who have shown a limited increase in the bactericidal activity of cefotaxime when aminoglycosides are added.
In this study, the beneficial effect of intrasplenic transplantation of hepatocytes or splenocytes was shown in animals with 75% hepatectomy and portacaval shunt but not in animals with total dehepatization by hepatic vascular exclusion. No enhancement of the phagocytic activity was observed in the animals with 75% hepatectomy and portacaval shunt after injection of hepatocytes or splenocytes. This study confirms the efficacy of hepatocytes for the treatment of experimental liver failure but shows that nonhepatic cells may be equally as effective. Metabolic activity of the transplanted cells and stimulation of the phagocytic activity of the reticuloendothelial system probably do not explain the therapeutic effect of the transplanted cells.
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Early region 1 of the adenovirus type 5 genome was replaced with a DNA sequence containing the gene coding for the hepatitis B surface antigen (HBsAg) flanked by the major late promoter from adenovirus 2 and processing and polyadenylylation signals from simian virus 40. In one type of hybrid virus only the adenovirus 2 major late promoter, including just 33 base pairs of the adenovirus type 2 tripartite leader, preceded the coding region of the HBsAg gene. In another, this region was preceded by both the adenovirus major late promoter and almost the entire tripartite leader. The structure of the substituted sequence in each of the recombinant viral DNAs was identical to that in the plasmids used to construct the viruses. Approximately equivalent amounts of HBsAg-specific mRNA were produced late in infection with each recombinant virus. Although HBsAg production was detected late in infection of the hybrid virus not containing the full tripartite leader sequence, its level was 1/70th of that obtained with the hybrid virus containing this sequence. One likely interpretation is that the presence of the tripartite leader at the 5' end of this mRNA is critical for the synthesis of HBsAg polypeptide in the late stage of infection. HBsAg produced upon infection with the hybrid adenoviruses was glycosylated and secreted into the culture medium as particles that were essentially indistinguishable from the 22-nm particles found in human serum.
An experimental study was conducted in rats to evaluate the sensitivity of the liver to infrared hyperthermia. A 15-min hyperthermia session treating only the liver was done in rats with a normal hepatic parenchyma and in rats with hepatocarcinoma induced by chronic 3'-diethylaminoazobenzene intoxication, at various ranges of intrahepatic temperature. In normal rats, 40-42 degrees C hyperthermia was well tolerated, but the mortality rate increased when the intrahepatic temperature exceeded 42 degrees C. In rats with tumors, a 40-42 degrees C hyperthermia session was well tolerated in case of small tumors, but resulted in a high mortality rate in case of large tumors. In all cases, death occurred as a consequence of liver injury. This study using a simple method of hyperthermia defines the thermosensitivity of the neoplastic or normal rat liver and provides a basis for further investigations on the effect of hyperthermia on experimental liver tumors.
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To perform kinetic studies of pancreatic hormones in freely moving rats, we have designed a new technique for hepatic portal vein catheterization through the left branch of the portal vein. Rats were followed up for 14-38 days. Catheter patency allowed blood sampling in 86% of rats on postoperative day 8 and in 55% on day 12. Rat growth, liver functions, and regional blood flows (measured with radiolabeled microspheres) were normal. In freely moving rats fasted for 16 h, portal venous concentrations in the basal state were: glucose, 112 +/- 4 mg/dl; insulin, 67 +/- 10 microU/ml; and glucagon, 480 +/- 74 pg/ml. These values remained stable for a 1-h period. Intravenous glucose infusion induced a biphasic insulin release, significant from the 1st min of infusion on, and a significant decline in glucagon level. Intravenous arginine stimulated both A and B cells. The portoperipheral hormone concentration gradient, which was detected in the basal state, increased during arginine infusion, particularly in regard to insulin. Ingestion of a mixed meal induced an early glucagon release and a sustained rise in insulin and glucose concentrations.
Efficacy of transplanted hepatocytes was evaluated in rats with a surgically induced acute hepatic failure. After 75% liver resection and portacaval shunt, the intrasplenic or intraperitoneal injection of 20 million isolated fresh hepatocytes was shown to significantly reduce the mortality rate. These results confirm that the transplantation of isolated hepatocytes may prevent death in rats with acute hepatic failure, and suggest that hepatocyte transplantation acts by a mechanism of hepatic support.
Two benign appearing endobronchial soft tissue lesions in two young patients (ages 33 and 26) were incompletely excised to conserve normal lung. Both tumors recurred four and seven years later. The first tumor had abundant small vessels in a myxomatous background (angiomyxoma); myofibroblasts formed the invasive component of the second tumor. To the best of our knowledge these two types of tumor have not been reported in the endobronchial location. Endobronchial lipoma, epithelial papilloma, inflammatory polyps, nodular sarcoid or amyloid and lymph nodes should be managed endoscopically. The potentially recurring and locally invasive endobronchial tumors such as granular cell myoblastoma, pleomorphic adenoma, angiomyxoma, and tumors of myofibroblast, and probably all other sessile benign tumors should be excised completely with part of the bronchial wall. The maximum preservation of normal lung usually does not conflict with this type of radical procedure.
The relationship between liver trophicity and the early (24 h) or late (14 days) modifications of the hepatic blood flow were studied in the rat after several types of portosystemic shunts (portacaval shunt, mesocaval shunt, portacaval transposition and arterialization of the portal vein after portacaval shunt). Twenty-four hrs after portacaval shunt, the total hepatic blood flow was decreased to 60 p. 100 of the initial value and remained so during the following days. Within a week, there was a liver atrophy with a decrease of the LW/BW to 60 p. 100 of the preoperative value. Fourteen days after operation, the hepatic blood flow per gram of liver was similar to that observed preoperatively. Whatever the type of shunt, there was a significant relationship between total hepatic blood flow and liver weight, 14 days after operation. Thus, after portal diversion, the quality of the blood perfusing the liver has little incidence upon the maintenance of liver trophicity. These results suggest that hemodynamic factors are more important than hormonal (pancreatic) factors in the constitution of liver atrophy after end-to-side portacaval shunt.