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Biomedical subjects

A Ribet

Publications and source records attributed to A Ribet.

At least 127 records · Page 7Linked to original sources
PubMed1977

[Problem posed by the prevention and detection of colorectal cancers].

The incidence of colonic and rectal carcinoma is in constant progression. The detection and destruction of polyps is the only effective means of reducing the number of adenocarcinomas. The technical means of detection are well known and fully proved: rectosigmoidoscopy, thin layer double contrast enema, colonoscopy. The true problem is that of the cost of this prevention. It is important to define high risk groups in which these tests should be carried out as a routine. Furthermore it is necessary to know whether blood tests or examination of the stools may be considered as a means of detection of polyp or at least certain types of potentially malignant polyp. without suggesting a considerable increase in the number of medical investigations, one may hope for better use of sigmoidoscopy and double contrast barium enema. These two examinations represent undoubtedly the essential factor in the diagnosis of colonic and rectal tumours.

Adenocarcinoma↗
PubMed1977

In-situ-isolated perfused rat pancreas: a new method for pharmacological studies of the exocrine pancreas.

A method of in-situ-isolated perfused rat pancreas is described. In situ perfusion of the isolated rat pancreas allows a faster set-up, thanks to a simpler operating procedure. The sensitivity of the isolated rat pancreas has been tested with secretin and cholecystokinin. The pancreas responds to doses of secretin as low as 0.005 CU/kg-h. Such a highly sensitive model might prove to be useful for the bioassay of secretin and the study of the effects of pancreatic secretagogues.

Animals↗
PubMed1977

Effects of catecholamines and their inhibitors on the isolated canine pancreas. I. Noradrenaline and isoprenaline.

alpha Adrenergic agonist (noradrenaline, 2, 20, and 200 mug) and antagonist (phenoxybenzamine, 15 mg), and beta adrenergic agonist (isoproterenol, 2, 20, and 200 mug), and antagonist (propranolol, 6 mg), were tested on isolated perfused canine pancreas under basal conditions, and under stimulation by a background of secretin (0.5 clinical unit per hr), or of caerulein (600 to 1200 ng per hr). Noradrenaline induced a strong vasoconstriction (inhibited by phenoxybenzamine), followed by a moderate vasodilation (possibly mechanical). Noradrenaline did not stimulate a resting pancreas and inhibited a pancreas from secreting in response to secretin or caerulein. After phenoxybenzamine, in the absence of vasoconstriction, this latter effect was reversed into a dose-dependent stimulation of hydrelatic secretion, suggesting that noradrenaline had a direct action on the secretory cell. There was no stimulation of protein and no acinar degranulation. Propranolol and atropine did not modify the effectiveness of noradrenaline. Isoprenaline had a weak vasodilatory effect but no effect on the secretion. Adrenergic blocking agents did not alter the response to secretin or caerulein.

Animals↗
PubMed1977

Effects of catecholamines and their inhibitors on the isolated canine pancreas. II. Dopamine.

Dopaminergic agonists (dopamine, 2, 10, 50, and 250 mug; apomorphine, 1 mg; noradrenaline, 2, 20, and 200 mug), and inhibitors (haloperidol, 5 mg; pentamethonium, 500 mg; phenoxybenzamine, 15 mg, and atropine sulfate, 10 mg), were tested on isolated perfused canine pancreas; under basal conditions and under stimulation by a background of secretin (0.1, 0.5, and 10.0 clinical unit per hr), or of caerulein (1200 ng per hr). Low doses of dopamine induced a vasodilation inhibited by haloperidol Large doses induced a vasoconstriction, presumably by stimulation of alpha adrenergic receptors. Dopamine stimulated hydrelatic secretion. The calculated maximal response was about one-half that of secretin. This response was inhibited by haloperidol but not by atropine, pentamethonium, and phenoxybenzamine. No acinar degranulation was observed after stimulation by dopamine. The response to secretin was not altered by haloperidol. It was concluded that blood vessels and pancreatic tissue contain specific receptors to dopamine different from secretin receptors. Secretory response to noradrenaline after phenoxy benzamine was inhibited by haloperidol, suggesting that this effect was mediated by the stimulation of dopamine receptors of the cells. A hypothetical representation of the interrelation between dopamine, secretin, and noradrenaline is discussed.

Animals↗
PubMed1977

Secretion of labelled proteins by the isolated dog pancreas in the response to secretin and cholecystokinin.

We compared the effects of secretin (10 clinical units/hur.) and cholecystokinin-pancreiozymin (CCK-PZ 10 Ivy units/hr.) from G.I.H. Laboratory in Stockholm, Sweden, on the secretion of radioactively labelled proteins in the pancreatic juice. This was carried out on isolated dog pancreas perfused "ex-vivo" with whole heparinized oxygenated blood. CCK-PZ and secretin were infused together and the results compared with a second series of experiments where secretin alone was administered, at the same dose. Both hormones caused a discharge of labelled proteins, which was linear over 55 minutes. Secretin increased the flow rate of the pancreatic juice and to a lesser extent the enzymatic protein output. CCK-PZ stimulated the mass flow of secretory proteins.

Animals↗
PubMed1976

[Clinical aspects and course of drug-induced upper digestive hemorrhage].

In a series of 500 patients admitted to hospital for upper digestive hemorrhage, the authors studied the influence of taking drugs on the clinical characteristics and course of the original disease. Taking aspirin is exceptional before rupture of esophageal varices. One may isolate a homogenous group of elderly women consuming aspirin and another anti-inflammatory drug, and bleeding from a gastric ulcer. One may also isolate another group of men, bleeding from acute gastro-duodenal lesions after taking aspirin alone. If one considers apart portal hypertension, owing to its extreme gravity, one may note that the prognosis depends on the age. One patient out of five, dies of hemorrhage after the age of 60 years. Taking an anti-inflammatory drug at this age is thus not harmless.

Adrenal Cortex Hormones↗
PubMed1976

[Immunologic evaluations during prolonged and chronic hepatitis. Significance for diagnosis and prognosis. 100 cases].

This retrospective study illustrates the valuable contribution of immunological studies carried out during the third month of hepatitis. The persistence of HBs antigen at this stage of the disease considerably increases the risk of chronic hepatitis though not necessarily implying progression to cirrhosis. The latter should be feared if there is a marked increase in gamma globulins and in the presence of a high level of anti-smooth muscle and antinuclear antibodies. Amongst the other immunological features, an increase in IgA and IgM also indicates the possibility of progression from chronic hepatitis to cirrhosis. Comparative study in chronic active hepatitis of HBs antigen and various antibodies indicates essentially three types: - CAH with Ag HBs without auto-antibodies - Auto-immune CAH without Ag HBs - CAH without auto-antibodies nor Ag HBs. Progression to cirrhosis appears to be less frequent in the first group than in the second.

Adolescent↗
PubMed1976

[Cholestatic hepatitis with a chronic course. 7 cases].

Cholestatic hepatitis, whilst having a longer course than cytolytic forms, in general regresses in a few months. The authors report here seven cases of cholestatic hepatitis lasting for more than 18 months. These chronic forms have certain characteristic features: - female predominance (6 cases out of 7). - a severe degree of cholestasis with, in particular, marked elevation of lipids, cholesterol and alkaline phosphatase. - the absence of Australia antibody and antigen, together with the absence of anti-smooth muscle antibody and anti-mitochondrial natibody. - a decrease in the number of permeable biliary canaliculi in the portal spaces. - a decrease in the number of permeable biliary canaliculi in the portal spaces. - a course which appears to be little influenced by various therapeutic measures. Although the final course seems satisfactory on the majority of cases, the possibility of a slow cirrhogenic transformation cannot be excluded in certain instances.

Adult↗
PubMed1976

Respiratory exchanges and acid-base balance during perfusion of ex vivo isolated pancreas.

We used the technique of ex vivo isolated pancreas, perfused with whole heparinized blood. The organ was stimulated by secretin (G.I.H. Stockolm, 0.1-5.0 clinic units/hr), and/or carbamylcholine (100-200 mug/hr). Oxygen consumption was increased under stimulation. This increase was a function of the dose of secretin and also of the bicarbonate output in the juice. Oxygen uptake increased further when carbamylcholine was super-imposed on secretin. This extra increase was independent of hemodynamic conditions of the organ perfusion. Arteriovenous difference in oxygen saturation did not increase when the gland was stimulated. It tended to decrease when the stimulation resulted in a marked vasodilatation. Thus, oxygen needs seemed to be neither the limiting factor of the response to a given stimulation nor the triggering mechanism of functional vasodilatation. Values of pCO2 were spread over a wide range from one experiment to another. However, it could be observed that CO2 efflux into the vein decreased under stimulation by secretin; in most experiments, CO2 efflux was even replaced by an apparent consumption of CO2 during the perfusion of the stimulated gland. Furthermore, arteriovenous pH difference increased following secretin stimulation. This increase was dose-related to secretin. These facts are discussed under the background of theories recently proposed for bicarbonate secretion.

Acid-Base Equilibrium↗
PubMed1976

Use of caerulein with submaximal doses of secretin as a test of pancreatic function in man.

The pancreatic exocrine secretory response to different combinations of the pancreozymin-like peptide caerulein and secretin was studied in 110 healthy control subjects and 32 patients with pancreatic disease. A combination of 0-5 CU/kg-h secretin and 75 ng/kg-h caerulein provided maximal or near-maximal stimulation of the secretion of both bicarbonate and pancreatic enzymes. The combination of stimulant peptides in the above doses was found to give excellent separation between the secretion of bicarbonate, lipase, and chymotrypsin of the control group and patients with chronic pancreatitis. A combination of caerulein and secretin represents a safe, reliable, and effective mean of stimulating pancreatic exocrine secretion for the purpose of testing pancreatic function.

Adult↗
PubMed1975

[Diagnostic and therapeutic problems posed by 2 cases of exudative enteropathy].

The authors report two cases of exsudative enteropathy characterised by the existence of oedema of the lower limbs associated with hypoproteinemia and marked lymphopenia with disturbances of the P.V.P. test. In both cases lymphography demonstrated major abnormalities with obvious obstruction in one case, and signs of slowing of lymph flow with appearances of dysplasia in the other. Surgery permitted us in one case, to discover a calcified lymph node probably due to tuberculosis. The etiology of these cases is discussed and seems to be mainly related to abnormalities of the lymphatic system. A low fat diet and administration of medium-chain triglycerides, gave an undoubted improvement when the treatment was followed by the patient. These two cases illustrate well the difficult diagnostic and therapeutic problems sometimes raised by syndromes of exsudative enteropathy, in particular owing to the many possible causes.

Adult↗
PubMed1975

Role of cholinergic mechanisms in the response to secretin of isolated canine pancreas.

The effects of carbamylcholine (CCH, 100 mug per hr) and of atropine (0.25, 1.0, and 10.0 mg per hr) on the response of the exocrine pancreas to secretin (0.1, 0.5, and 5.0 clinic units per hr) were studied using the isolated canine pancreas perfused with whole heparin-treated blood. CCH induced a sharp decrease in D50 (dose of secretin which elicits half the calculated maximal response) but no increase in maximal response to secretin. Experiments performed under different haemodynamic conditions show that this potentiating effect (synergism) is partly due to vasomotor modifications and chiefly to the action of CCH on the receptor of secretin. Although this work indicates that cholinergic tone is not necessary for secretin-induced hydrelatic response to occur, it evidences that this cholinergic tone plays a major role in modulating the pancreatic response to submaximal doses of secretin. It has also been found that large doses of atropine (10 mg per hr) were necessary to achieve a complete inhibition of enzymatic response to CCH. Even at these high doses, however, enzymatic response to secretin and cholecystokinin-pancreozymin were not significantly inhibited.

Animals↗
PubMed1975

Glucagon treatment of experimental acute pancreatitis.

CFY male rats anaesthetized with pentobarbital were used in different groups for inducing acute pancreatitis by the retrograde injection either of 1 mg elastase, 5 mg trypsin, 4 mg lysolecithin, 10 mg Na-taurocholate in 0.2 ml volume or of 0.3 m. sunflower oil. In each group laparatomized animals served for control. The animals with pancreatitis were treated either with 15 mug/b.w.kg/hour glucagon or with physiological saline for 72 hours. Twenty-four and 72 hours after inducing pancreatitis glucagon did not influence the significant fall in blood pressure elicited by the intraductal injection of trypsin or elastase or in the plasma calcium level in pancreatitis induced by trypsin or sunflower oil. Neither did glucagon affect the significant increase of plasma lipase activity in pancreatitis induced by trypsin or taurocholate. It also failed to reduce the 24-hour mortality rate and the extension of fat tissue necrosis in the abdominal cavity of pancreatitic animals. In contrast, glucagon treatment significantly reduced the amount of abdominal exudate associated with bile salt induced pancreatitis and, probably due to its pancreatic blood flow increasing effect, seemed to moderate the degree of tissue damage elicited in the pancreas by detergents such as taurocholate or lysolecithin.

Acute Disease↗