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Biomedical subjects

A Lacroix

Publications and source records attributed to A Lacroix.

At least 163 records · Page 9Linked to original sources
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↗
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↗
PubMed1973

[Allergology].

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Allergens↗
PubMedDate not supplied

Hormone receptor abnormalities in adrenal Cushing's syndrome.

Cortisol secretion in ACTH-independent primary adrenal Cushing's syndromes was previously believed to be autonomous. In most cases, the pathophysiology of the disease was largely unknown. However, recent work by our group and others have shown that these cortisol-producing adrenocortical tumors may be under the control of inappropriate, illicit or ectopic hormone receptors. This review provides a rapid overview of the physiology of the normal adrenal cortex and outlines recent findings supporting the hypothesis that cortisol production may be regulated by a diversity of abnormal or ectopic hormone receptors in primary adrenal Cushing's syndrome.

Adrenal Gland Diseases↗
PubMedDate not supplied

Purification and partial characterization of a rat kidney aldehyde dehydrogenase that oxidizes retinal to retinoic acid.

A NAD-dependent aldehyde dehydrogenase (EC 1.2.1.3) which catalyzes the oxidation of retinal to retinoic acid was purified to homogeneity from rat kidney by using Affi-Gel blue affinity chromatography and chromatofocusing, followed by Mono-Q anion-exchange chromatography. The apparent molecular weight of the native enzyme determined by size-exclusion fast protein liquid chromatography was 140,000. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis gave a subunit molecular weight of 53,000. The isoelectric point as measured by chromatofocusing was 8.5. The enzyme also catalyzed the oxidation of acetaldehyde, but showed much lower Km value for the retinal substrate. We suggest that aldehyde dehydrogenase found in the kidney may be a specific retinal dehydrogenase, involved in vitamin A metabolism.

Acetaldehyde↗
PubMedDate not supplied

Abnormal expression and function of hormone receptors in adrenal Cushing's syndrome.

The initial description of GIP-dependent Cushing's syndrome suggested that abnormal or ectopic expression of adrenal receptors for various ligands may underlie other cases of ACTH-independent hypercortisolism. GIP-dependent Cushing's syndrome has been described in patients with unilateral adenomas or bilateral ACTH-independent macronodular adrenal hyperplasia (AIMAH) and results from the adrenal overexpression of non-mutated GIP receptor. In AIMAH, other patients were identified in whom regulation of cortisol production resulted from an abnormal adrenocortical response either to vasopressin, beta-adrenergic receptor agonists, hCG/LH, or serotonin 5-HT-4 receptor agonists. The identification of the presence of an abnormal adrenal receptor offers the possibility of a new pharmacological approach to control hypercortisolism by suppressing the endogenous ligands or by using specific antagonists of the abnormal receptor.

Adrenal Cortex↗
PubMedDate not supplied

[Is it possible to improve the teaching methods of physicians who instruct patients? Comparative analysis of the same courses given before and after teacher's training].

The goal of the present study is to compare the pedagogic involvement of two groups of doctors, both of which were in charge of teaching the same courses to diabetic patients. Important structural differences were-shown exit between the two series of courses. The first group of ten doctors (who not undergone any pedagogic training) applied either ex-catedra teaching methods or proceeded by systematically asking questions to the patients. These scholastic methods led to passive attitudes in their patients in listening and replies to a large number of questions. In the second group of ten doctors (who had undergone pedagogic training) learning practices and a stimulating didactic material were used which resulted in more diversified and more attractive responses in the participation of the patients. Providing improved didactic means on the behalf of the doctors is aimed at obtaining better knowledge from patients who have themselves to assume the self-management of their treatment.

Diabetes Mellitus↗