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Biomedical subjects

D Castaing

Publications and source records attributed to D Castaing.

At least 145 records · Page 8Linked to original sources

[Value of peroperative ultrasonography in the surgery of hepatic metastases].

16 patients with hepatic metastases and 35 patients with a cancer of the gastrointestinal tract with no apparent metastases on the pre-operative survey were studied prospectively in order to compare the effectiveness of intra-operative ultrasonography and other morphological examinations in the detection of tumour. In this study, the topographical precision of the various morphological examinations was also assessed. This precision is fundamental for modern surgery for hepatic metastases, as it allows limited anatomical resections which are associated with a decreased operative risk, while maintaining the same long term results as wide resections.

Humans↗

[Increase in urinary uric acid in the rat following portacaval shunt. The action of clofibrate].

Two successive experiments on rats confirm that a portocaval shunt leads to a substantial increase in uricosuria, which does not climax in the first week postoperatively. Clofibrate, an inductive liver enzyme, significantly reduces the uricosuria, but only after a certain timelag. Uricosuria, the degree of which varies with individual rats, leads to crystallization of uric acid, mainly in the form of ammonium urate, but polyuria secondary to portocaval shunt tends to inhibit the crystallization. A reduced water intake one day out of two facilitates the crystallization after a portocaval shunt.

Animals↗

Cholesterol metabolism in lean and obese Zucker rats: effects of portacaval anastomosis.

The effects of portacaval anastomosis (PCA) on cholesterol biodynamics of male adult (fa/fa) Zucker rats and their lean littermates were studied with an isotopic equilibrium method. Animals were fed with a sucrose-rich semi-purified diet. Obese rats were hypercholesterolemic (2.03 +/- 0.14 vs 1.06 +/- 0.7 mg/ml), had a cholesterol-enriched liver (135.3 +/- 14.5 vs 40.0 +/- 2.6 mg/liver) and accumulated cholesterol in body pools. However no difference in the rates of cholesterol absorption, synthesis, fecal elimination or transformation into bile acids distinguished obese from lean Zucker rats. In both lean and obese rats, PCA decreased cholesterolemia by about 28 per cent and liver weight by 40 per cent while the total cholesterol content of the liver was not affected. Input of synthesized cholesterol (internal secretion) was strikingly decreased by the shunt (from 13.2 +/- 0.6 and 12.6 +/- 0.7 mg/day/rat before PCA, to 8.9 +/- 0.8 and 8.6 +/- 1.0 mg/day/rat after PCA) in lean and obese rats respectively. A similar decrease was observed in the cholesterol transformation into bile acids. Since the activity of the gut for cholesterol synthesis, as shown by the fecal external secretion (cholesterol synthesized by the gut and directly eliminated in the gut and feces) was probably not modified, the reduction of internal secretion induced by PCA resulted from decreased hepatic cholesterogenesis. It is suggested that this decrease may be one of the factors involved in the lowering effect of PCA on plasma cholesterol level.

Animals↗

[Surgical treatment of hepatic metastases].

355 patients with hepatic metastases were followed between 1970 and 1984 at the Hôpital Paul Brousse. 132 cases were of colonic origin: 32 were treated by means of hepatic resection (including 5 metastasectomies), 7 by intra-hepatic anastomosis and 5 by devascularisation. The other 88 patients did not receive any surgical treatment. In 148 of the other 233 patients, the metastases were of non colonic gastro-intestinal or rectal origin and in the remaining 75 cases the metastases were derived from another site. 12 patients were treated by hepatic resection, 6 by devascularisation, 2 by intra-hepatic anastomosis and 2 by intubation of the bile ducts. One patient (0.5 per cent) died during the post-operative period following these operations. The long term survival was 73 per cent at 1 year and 29 per cent at 3 years. In conclusion, some patients are definitely cured by hepatic resection, although these patients cannot be predicted. For this reason, the surgeon's role consists of trying to decrease as much as possible the operative risk and to propose this type of treatment to all patients in which it may be beneficial.

Colonic Neoplasms↗

[Brain-death unit and renal transplantation. Evaluation of 5 years' experience].

From 1977 to 1982, 170 potential organ donors were referred to "a brain-death unit". A vast majority of these patients were provided by intensive care units of district general hospitals from Ile-de-France. This fact confirms the dispersion of potential organ donors and the usefulness of an organ-procurement structure based in an University Hospital. Its effectiveness is demonstrated by an harvesting rate of 58%, largely over the already published reports in case of absence of such a center. It is concluded that the adoption of this system by other hospitals would significantly increase the number of cadaver kidney grafts available for transplantation whereas actually the number of kidney grafts remains dramatically low in France.

Adolescent↗

A new technique for hepatic portal vein catheterization in freely moving rats.

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.

Animals↗

[Cost of the surgical treatment of gallbladder lithiasis. Example of an attempted rationalization of medical care and expenditure].

A medical audit was conducted in a Paris hospital on patients who, in 1975, underwent cholecystectomy for uncomplicated gallstones. The audit comprised the duration of pre- and post-operative hospitalisation, the Social Security grading of medical acts, biochemical and radiological examinations and the quality of medical care, as assessed by morbidity and mortality rates. The results were brought to the knowledge of all members of the surgical team concerned. Similar studies conducted two and five years later showed that self-restriction on the part of the physicians resulted in improved costs through shorter stays in hospital (especially before surgery) and less extensive and numerous examinations, the incidence of complications remaining the same.

Adult↗

Surgical management of gallstones in cirrhotic patients.

Among the cirrhotic patients admitted to our department, 64 (17 percent) were found to have cholelithiasis. In 14 patients (22 percent), cholelithiasis caused cholecystitis, obstructive jaundice, or biliary pain. These 14 patients were operated on and underwent cholecystectomy. There was one postoperative complication (gastrointestinal bleeding from esophageal varices) and one death (due to acute respiratory failure). In 50 patients (78 percent) cholelithiasis was asymptomatic. Ten of the 50 patients died from liver failure and the stones were discovered at necropsy. Seven of the patients had radiographically demonstrated stones that were not operated on. They are alive at the present time, more than 2 years later. In the remaining 33 patients, the stones were discovered during portasystemic shunt procedures. In these patients, cholelithiasis was systematically treated by cholecystectomy (8 patients) or cholecystolithotomy (25 patients). Postoperative mortality and morbidity rates were not different in these 33 patients when compared with the rates in 170 patients who underwent portal surgery alone during the same period. Our results confirm the high incidence of cholelithiasis in cirrhotic patients. Complications of gallstones are not frequent but require an emergency operation that carries a high risk in these patients. On the other hand, elective surgical treatment of asymptomatic cholelithiasis at the time of portal diversion does not bear any peculiar risk. In such a situation, cholecystolithotomy is easier and probably safer than cholecystectomy.

Cholecystectomy↗

Effect of portacaval or mesentericocaval anastomosis on cholesterol metabolism in rats.

Portacaval anastomosis (PCA) lowered by 50% the cholesterol concentration in the plasma of rats. The free and esterified cholesterol contents in the lipoproteins were decreased with the very low density lipoproteins most affected (-85%). Cholesterol concentration as total content in the liver was reduced. The major change in the cholesterol metabolism, as studied with an isotopic equilibrium method, was the decrease in the intestinal absorption coefficient of dietary cholesterol (56.0 +/- 2.7% instead of 73.3 +/- 1.9% in controls). The rate of cholesterol transformation into bile acids was decreased (10.5 +/- 0.3 vs 14.5 +/- 0.5 mg/day/rat in controls). The rate of internal secretion of cholesterol was slightly reduced while the rate of fecal external secretion was increased, suggesting that the synthesis of cholesterol by extra-digestive tissues (including liver) was reduced after PCA. The effects of PCA on cholesterol metabolism were similar to those described for glucagon administration. Since this shunt results in hyperglucagonemia, it is suggested that this hormonal perturbation was the main factor involved in the modifications of cholesterol metabolism after PCA. Moreover, mesentericocaval anastomosis, which shunts only the intestinal blood and allows the pancreatic hormones a normal transport through the liver, did not significantly modify cholesterol metabolism. Only cholesterolemia (-28%) and the absorption coefficient of dietary cholesterol (66.0 +/- 2.3%) were slightly reduced.

Animals↗

[Removal of the kidney following in situ perfusion].

Kidneys of potential donors undergoing sudden cardiac arrest are generally not gathered because the warm ischemia time is too long until nephrectomy. A rapid in situ cold perfusion technique was developed to preserve kidneys in 21 brain-dead patients after cardiac arrest not responding to cardiac resuscitation. In 7 of the 21 potential donors, the in situ perfusion was unsuccessful. In 14 other subjects this technique permitted to save 15 transplantable kidneys; 1 month after grafting, the renal function was similar to that observed in kidneys gathered in living patients. The in situ perfusion technique allows to increase by nearly 10% the efficacy of kidney gathering.

Brain Death↗

Microlithiasis of the gallbladder.

Patients with microlithiasis represent a small group compared with the general population of patients with gallstones. However, it is a group which deserves particular attention because of the risk of acute pancreatitis. For this reason, cholecystectomy should be advocated in patients considered to be at low anesthetic risk in which echography or roentgenography detects the presence of minute stones in the gallbladder, even in the absence of biliary disorders.

Acute Disease↗

[Changes in hepatic blood flow after various types of portal shunt in the rat].

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.

Animals↗

Liver atrophy and encephalopathy after portacaval shunt in the rat.

The effect of various types of portal diversion (portacaval, mesocaval and pancreatico-splenocaval anastomoses, portacaval transposition and arterialization) on liver atrophy and post-shunt encephalopathy was studied in the rat. Among all diversions, only portacaval anastomosis produced dramatic liver atrophy and encephalopathy. Moreover, portacaval anastomosis was also the only portal diversion which induced low body weight gain. There was no correlation between blood ammonia levels and encephalopathy. Liver atrophy was always correlated to a decrease of hepatic blood flow. Diminution of liver blood flow was only slight following partial (either mesenteric or pancreatico-splenic) diversion of portal blood and nil after portacaval transposition or anastomosis. These results suggest that: (1) pancreatic (insulin-rich) blood is not essential for maintenance of liver trophicity. Hemodynamic factors seem to be predominant in the pathogenesis of post-shunt liver atrophy. (2) Post-shunt encephalopathy arises only when total diversion of the portal blood and liver atrophy are associated.

Ammonia↗