Contexte : Le developpement d'une autonomie intellectuelle et d'une capacite de recul critique, face au developpement des connaissances scientifiques, passe par une meilleure comprehension des modes de constructio n du savoir scientifique et de renouvellement des connaissances. But et methodes : Analyser les conceptions sur la nature de la science de six etudiants en medecine francais ayant suivi l'enseignement scientifique des trois premieres annees des etudes medicales, a partir d'entretiens individuels semi-structures, suivis d'une analyse qualitative du contenu. Resultats : Une certaine homogeneite des conceptions a ete retrouvee chez les six etudiants. Elles sont a tendance empiriste, realiste et positiviste tant dans les opinions traitant des buts de la science, que de ses finalites, de son contexte de mise en oeuvre ou de ses methodes. Une etudiante presente cependant une approche plus constructiviste de la nature du renouvellement des connaissances. Des conflits cognitifs se sont manifestes chez quatre etudiants dans leurs opinions sur les methodes de validation des resultats, la notion d'universalite des connaissances et sur la demarche scientifique. Conclusion : Ce travail met en evidence l'importance d'un enseignement d'Epistemologie en Medecine. Les deux annees du premier cycle et la premiere annee du deuxieme cycle offrent l'opportunite d'introduire des exposes historiques et prospectifs concernant l'evolution des disciplines. Une formation specifique des enseignants a l'histoire des sciences apparait souhaitable.

Background Cyclosporin A (CyA) may induce acute nephrotoxicity. The question has been raised of the possible long-term unfavorable course of CyA-induced lesions. Advantage was taken of a large cohort of diabetic patients treated for several months using moderate CyA dosage to evaluate the long-term evolution of renal function in such patients.Methods Two hundred and eighty five recently diagnosed type 1 diabetic patients having received CyA for a mean of 19.9 months were monitored for 13 years, in parallel with 100 similar patients treated with insulin alone.Results In the CyA-treated group, a transient increase in creatininemia levels occurred during the first 18 months of treatment associated with a transient increase in renal vascular resistance. Both effects disappeared later on: creatininemia levels then remained normal. Inulin and p-aminohippurate (PAH) clearances remained normal throughout follow-up. Neither permanent renal failure nor progressive deterioration of renal function occurred in either group or in individual patients. A 10 to 12% increase in inulin and PAH clearance was elicited by TV amino acid infusion at 7 to 10 years, a finding consistent with a normal renal functional reserve. Patients with moderate kidney lesions on biopsy at 1 year had normal and stable clearance values at 7 to 13 years. The prevalence of arterial hypertension and retinopathy was lower in the CyA-treated group than in the control group, possibly because of the tighter metabolic control obtained in the CyA group.Conclusion These results suggest that low-dose CyA treatment combined with thorough monitoring does not result in long-term renal dysfunction. Copyright (C) 2002 John Wiley Sons, Ltd.

But : Ce travail décrit une formation mise en place à la faculté de médecine Xavier Bichat dans le cursus préclinique des études médicales. Elle a pour but de développer les capacités de communication des étudiants, en utilisant une technique journalistique : le « deux minutes radio ». Méthodes : Les étudiants ont été répartis en 5 groupes de 20 pendant 2 demi-journée de 3 heures. Cinq textes sur la douleur leur ont été proposés. Cette formation s’est déroulée en quatre étapes : 1- apprentissage de la technique de transformation d’un texte-source en une communication radiophonique de vulgarisation ; 2- travail d’analyse et transformation du texte ; 3- présentation orale au groupe d’une durée de 2 minutes. Résultats : La performance globale des orateurs (score maximal de 5) évaluée par les enseignants et les étudiants (Q1-Q3) concerne la cohérence du contenu du « deux minutes radio » et l’effet suscité par l’exposé sur le groupe ; les scores sont respectivement de 3,91 + 0,11 et de 4,39 + 0,07. Il existe une corrélation significative entre l’évaluation des enseignants et celle des étudiants (p < 0,0001). Un score moyen de 3,76 + 0,24 rend compte de l’évaluation par les enseignants du respect de la technique de communication. Conclusions : Les étudiants ont acquis par cette technique des aptitudes à délivrer un message concis et clair les préparant à la pratique de l’entretien médical. Cette formation peut être reproduite facilement sur d’autres sites.

Seven normotensive untreated patients with obstructive sleep apnea (OSA) and five control subjects without OSA were compared. Patients with cardiac dilation, chronic airflow limitation, liver and kidney disease, or diabetes mellitus were excluded. Change in pressure-heart rate relation to alpha-adrenergic stimulation (P-HRR), extracellular volume (ECV), and plasma volume (Vp) were measured during daytime. Plasma atrial natriuretic peptide (ANP), plasma renin and aldosterone concentrations were obtained at 1 hour intervals during the night. A mean apnea/hypopnea index (AHI) of 52.2 +/- 23.9/h and a mean lowest arterial oxygen saturation (SaO2) of 61.2 +/- 19.3% (mean +/- SD) were determined from polysomnographic monitoring in the patient group. Release of ANP was significantly higher during sleep in OSA patients than in control subjects (P < .01), with a maximum concentration between 4 and 6 AM in the former. Daytime ECV was significantly higher (P < .05) and Vp significantly lower (P < .05) in OSA patients. Night maximum concentration of ANP (max ANP) was negatively related to AHI (P < .05). P-HRR was negatively related to AHI (P < .05) and positively related to max ANP (P < .05). In conclusion, OSA syndrome alters hormonal system control of body fluid compartment regulation. The decreased response in night max ANP secretion in the most severe OSA patients could be explained by the smaller Vp observed in these patients, decreasing atrial and ventricular pressure loading. Furthermore, alteration of P-HRR, correlated to AHI and max ANP, strengthens the hypothesis that patients who develop hypertension are those in whom the protective mechanism of ANP release failed.

Seven normotensive untreated patients with significantly lower (P õ .05 ) in OSA patients. Night maximum concentration of ANP (max ANP) obstructive sleep apnea (OSA) and five control was negatively related to AHI ( P õ .05) . P-HRR subjects without OSA were compared. Patients was negatively related to AHI ( P õ .05) and with cardiac dilation, chronic airflow limitation, positively related to max ANP ( P õ .05) . In liver and kidney disease, or diabetes mellitus conclusion, OSA syndrome alters hormonal were excluded. Change in pressure-heart rate system control of body fluid compartment relation to a-adrenergic stimulation (P-HRR), regulation. The decreased response in night max extracellular volume (ECV) , and plasma volume ANP secretion in the most severe OSA patients (Vp ) were measured during daytime. Plasma atrial could be explained by the smaller Vp observed in natriuretic peptide (ANP), plasma renin and these patients, decreasing atrial and ventricular aldosterone concentrations were obtained at 1 pressure loading. Furthermore, alteration of Phour intervals during the night. A mean apnea/ HRR, correlated to AHI and max ANP, hypopnea index (AHI) of 52.2 { 23.9 /h and a strengthens the hypothesis that patients who mean lowest arterial oxygen saturation (SaO2 ) of develop hypertension are those in whom the 61.2 { 19.3% (mean { SD) were determined from protective mechanism of ANP release failed. polysomnographic monitoring in the patient q 1997 American Journal of Hypertension, Ltd. Am group. Release of ANP was significantly higher J Hypertens 1997;10:24–31 during sleep in OSA patients than in control subjects (P õ .01 ) , with a maximum concentration

Background and Design: Cyclosporine has proved to be highly effective in the treatment of psoriasis. However, cyclosporine is potentially toxic. Side effects include renal toxic effects, hypertension, and an increased risk of malignant neoplasm. The toxicity of cyclosporine is dose-related, yet the safe duration of treatment is undefined. We studied the hospital records of all patients with psoriasis treated with cyclosporine at Saint Louis Hospital, Paris, France, between January 1, 1987, and December 31, 1993. In total, 122 patients treated for 3 to 76 months were evaluated.Results: The percentage of patients who discontinued treatment because of side effects rose from a mean+/-SD of 14%+/-2.4% at 12 months to 41%+/-6.7% at 48 months. An increase in serum creatinine levels to more than 30% above the baseline value occurred in 53 patients after a median treatment time of 23 months. Hypertension developed in 29 patients after a median treatment time of 53 months. Three initial patient characteristics-age older than 50 years (P=.04), initial diastolic pressure higher than 75 mm Hg (P=.05),and serum creatinine levels more than 100 mu mol/L (1.1 mg/dL) (P=.02, log rank test)-predicted discontinuation of cyclosporine because of side effects.Conclusions: The risk of cyclosporine-induced toxic effects increases with age of the patient and with preexisting hypertension or high serum creatinine levels. The data suggest that the incidence of side effects increases with time. Thus, cyclosporine is not an acceptable long-term monotherapy for psoriasis.

Renal functional reserve represents the capacity of the kidney to increase its level of operation in response to certain demands. The reserve of glomerular filtration rate and of renal blood flow is discussed from the following points of view: evaluation, measurement, mechanisms involved and significance. Data from the literature are discussed which show (i) that the mechanism of the hyperfiltration seen in the early stage of diabetic nephropathy may be different from the hyperfiltration induced by infusion of amino acids, (ii) that the remaining kidney in healthy kidney donors maintains its functional reserve, and (iii) that the functional reserve is fairly well maintained as long as the glomerular filtration rate is decreased only moderately. The reserve of tubular functional capacity is discussed from the point of view of concentration and dilution and of acidification and alkalinization.

One hundred seven acutely ill ventilated patients were prospectively studied to ascertain the severity and frequency of alterations in gas exchange and hemodynamic parameters during brief bronchoscopy. Sedation was performed using midazolam (0.1 mg/kg IV) without topical anesthesia. An average decline in PaO2 of 26 percent was observed at the end of the procedure, compared to the baseline value, and this was associated with a mild increase in PaCO2 in spite of the use of a special adapter. Alterations in mean systolic blood pressure appeared to be modest, consisting of a 10 percent decrease from the control level, related to sedation, and a 10 percent rise from baseline during the procedure, associated with a concomitant mild tachycardia. At that time, central hemodynamic measurements performed in a subset of 31 patients showed a significant increase in cardiac output associated with higher pulmonary wedge pressure. Fourteen patients developed hypoxemia of less than 60 mm Hg on FIO2 adjusted to 0.8. Of the ten risk factors univariately associated with hypoxemia, only the presence of ARDS (p less than 0.001) and "fighting" the ventilator during the procedure (p less than 0.05) remained significant after stepwise logistic regression. Attempts to prevent hypoxemia in critically ill patients should focus on inducing complete sedation, with careful attention to hemodynamic status, or providing maximal levels of oxygen to the ventilator (or both).

Left ventricular hypertrophy has been found to be associated with a reduction of coronary vascular reserve, which could be responsible for episodes of myocardial ischemia. To evaluate coronary flow and resistance reserve in patients with chronic aortic regurgitation, coronary sinus blood flow and coronary resistance were measured before and after an intravenous dipyridamole infusion (0.14 mg/kg per min X 4 min) in eight control subjects and eight patients with aortic regurgitation, exertional angina pectoris and normal coronary arteriograms. Coronary flow reserve, evaluated by the dipyridamole/basal coronary sinus blood flow ratio, and coronary resistance reserve, evaluated by the basal/dipyridamole coronary resistance ratio, were both significantly reduced in patients with aortic regurgitation (1.67 +/- 0.40 versus 4.03 +/- 0.52 in control subjects, p less than 0.001 and 1.71 +/- 0.50 versus 4.38 +/- 0.88 in control subjects, p less than 0.001, respectively). In patients with aortic regurgitation, basal coronary sinus blood flow was higher than in control subjects (276 +/- 81 versus 105 +/- 24 ml/min, respectively, p less than 0.001) and basal coronary resistance was lower (0.31 +/- 0.13 versus 0.95 +/- 0.17 mm Hg/ml per min, respectively, p less than 0.001), but coronary blood flow and resistance after dipyridamole were not significantly different in the two groups (461 +/- 159 versus 418 +/- 98 ml/min in control subjects, 0.19 +/- 0.11 versus 0.22 +/- 0.04 mm Hg/ml per min in control subjects, respectively). These data demonstrate that coronary reserve is severely reduced in patients with chronic aortic regurgitation and exertional angina.(ABSTRACT TRUNCATED AT 250 WORDS)

Renal tubular dysfunction was investigated in two patients with meticillin-induced interstitial nephritis. Some degree of renal failure persisted after the acute episode in both cases. The first patient was investigated 10 weeks after the onset of the nephropathy. Nephrogenic diabetes insipidus and distal tubular acidosis were demonstrated. The second patient was investigated 7 months after the onset of the nephropathy. A major impairment in urinary concentration ability was demonstrated. Neither patient had proximal tubular dysfunction. These data show that meticillin-induced interstitial nephritis may be responsible for distal tubular abnormalities, namely nephrogenic diabetes insipidus and distal tubular acidosis, which may persist long after the onset of the nephropathy.

Coronary reserve can be assessed by the ratio of coronary blood flow after "maximum" vasodilation to control flow. The intravenous infusion of dipyridamole (0.56 mg X kg-1) is considered to elicit maximum coronary vasodilation. The present study was designed to compare coronary flow and resistance responses to intravenous dipyridamole and intracoronary injection of contrast medium (ioxaglate), this latter technique being frequently used in digital radiology to stimulate hyperemia. The comparison was performed in seven normal patients, nine patients with coronary artery disease, and 16 patients with dilated cardiomyopathy. Coronary flow reserve was calculated as the ratio of peak flow after dipyridamole or contrast medium to control flow, and coronary resistance reserve was calculated as the ratio of minimal to control coronary resistance after each stimulus. Although flow reserve after dipyridamole was approximately twice that obtained after contrast medium in the normal group (4.01 +/- 0.56 vs 2.02 +/- 0.24) there was a close and linear relationship between coronary flow and resistance reserve estimated by both techniques (r = 0.846, p less than 0.001 for flow reserve ratios, and r = 0.844 p less than 0.001 for resistance reserve ratios). However, contrast-induced hyperemia identified 13/25 (52%) of patients with coronary artery disease or dilated cardiomyopathy as having a reduced flow reserve, while dipyridamole revealed a restrained coronary flow reserve in 20/25 (80%) of these patients. Similar proportions were obtained when using coronary resistance reserve (56% for contrast vs 80% for dipyridamole). (ABSTRACT TRUNCATED AT 250 WORDS)