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Biomedical subjects

P Landais

Publications and source records attributed to P Landais.

At least 73 records · Page 4Linked to original sources
PubMed1994

[Role of physician-patient dialogue in the "white-coat" effect in arterial hypertension. Reproducibility during the consultation. Existence despite of treatment].

A prospective study in 35 hypertensive patients indicated that blood pressure during a visit was increased by a "white coat" effect in 33 cases out of 35. On average, systolic blood pressure during a visit was 12.4 mmHg (+9%) higher than ambulatory systolic pressure (p < 0.0001), while diastolic pressure was increased by 10.3 mmHg (+11%, p < 0.0001). This alerting reaction is caused above all by dialogue between the physician and patient and lessens during periods of silence. Systolic pressure increased by 13.8 mmHg (+10%, p < 0.0001) during dialogue in comparison with period of silence, and by 18.9 mmHg (+14%, p < 0.0001) in comparison with ambulatory period. Diastolic pressure increased by 8 mmHg (+8%, p < 0.0001) and 14 mmHg (+14%, p < 0.0001) under the same circumstances. This effect would appear to depend upon the emotional content of the dialogue. It could recur to the same extent 30 minutes after the start of the visit. This effect is identical in treated and non-treated hypertensive patients. Thus the persistence of high pressure levels measured during medical visits of treated patients should lead to evaluation of their ambulatory pressure before concluding that treatment is ineffective.

Ambulatory Care↗
PubMed1994

Extracorporeal lithotripsy associated with laparoscopic cholecystectomy: results of 60 patients.

Gallbladder extracorporeal lithotripsy was performed on 60 patients before laparoscopic cholecystectomy. Of the 44 cases with solitary stones (range, 17-45 mm; mean +/- SEM, 26.9 +/- 0.1 mm), satisfactory fragmentation was obtained in 77.2%. Of the 16 cases with multiple stones (range, 11-25 mm; mean +/- SEM, 14.9 +/- 0.7 mm), satisfactory fragmentation was obtained in 18.75%. Minimal adverse effects were observed both clinically and macroscopically during surgery. Upon histologic investigation, only two small gallbladder lesions could be attributed to extracorporeal lithotripsy. No changes in blood chemistry tests were recorded. When carried out with high performance equipment, extracorporeal lithotripsy appears to be an interesting procedure that permits an appreciable reduction in the number of parietal wall incisions that need to be widened, therefore simplifying laparoscopic cholecystectomy when dealing with large stones.

Adult↗
PubMed1994

[Evaluation of the diagnostic contribution of a test. Main information indices].

Evaluating a new diagnostic test is an essential step required before using a new examination technique. The information concerning the disease provided by the test must be examined in terms of diagnostic value and cost. A test can be evaluated using several indexes. For tests giving binary results, the main information indexes were defined and the calculation of the index was illustrated by an example. The sensitivity, specificity, the Youden index, and the positive and negative predictive values were presented together with the likelihood and odds-ratio. For tests giving quantitative results, the analysis of the ROC curves was discussed. Indexes were interpreted in terms of disease prevalence, the modalities (diagnosis, screening) for applying the test, the sampling technique for the tested population, the gain in diagnosis, and cost of the examination.

Diagnosis↗
PubMed1993

Relief of akinesia by apomorphine and cerebral metabolic changes in Parkinson's disease.

The cerebral metabolic rate of glucose was measured in 14 Parkinson's disease patients with severe on-off fluctuations. Two positron emission tomography (PET) scans with [18F]fluorodeoxyglucose were performed, one after a challenge of subcutaneous apomorphine at a dose able to relieve akinesia within 15 min and the other with the vehicle. Apomorphine reduced glucose utilization by 4-6% in the lenticular nuclei and the occipital cortex and by 6-9% in the thalamic nuclei, but this effect was not statistically significant. Thus, central stimulation of dopamine receptors by apomorphine in advanced Parkinson's disease is not associated with cerebral metabolic changes as assessed by PET. Despite a dramatic improvement of the motor state, the global neuronal activity in the striatum and its downstream projections remains stable, suggesting an equilibrium between excitatory and inhibitory dopaminergic activities.

Aged↗
PubMed1993

Thalamic stimulation and suppression of parkinsonian tremor. Evidence of a cerebellar deactivation using positron emission tomography.

Parkinsonian tremor can be abolished by chronic high frequency thalamic stimulation of the ventral intermediate nucleus. We have studied six patients with unilateral Parkinson's disease. The patients had an electrode chronically implanted in the ventral intermediate nucleus of the thalamus. We measured changes in cerebral activity by positron emission tomography using an index of regional cerebral blood flow (rCBF). Each patient was scanned in three states: (i) tremor without stimulation (condition A); (ii) tremor with ineffective stimulation (condition B); (iii) tremor abolished by effective stimulation (condition C). The suppression of tremor (C compared with B) was specifically associated with a decrease of rCBF in the cerebellum, whereas the ineffective stimulation (B compared with A) induced a decrease of rCBF in homolateral cerebral cortex. The results give evidence for different contributions from cortex and cerebellum to the generation of parkinsonian tremor and suggest that tremor suppression is mainly associated with a decrease of synaptic activity in the cerebellum.

Aged↗
PubMed1993

Improvement of diabetic control and acceptability of a three-injection insulin regimen in diabetic adolescents. A multicenter controlled study.

OBJECTIVE: To compare the effectiveness and acceptability of a three-injection insulin regimen with the conventional two-injection therapy in an unselected population of diabetic adolescents. RESEARCH DESIGN AND METHODS: Some 205 patients aged 10-18 yr with IDDM, who were previously treated with two daily insulin injections, were included without any selection into a randomized trial. They were either switched to three (regular prebreakfast, regular prelunch, and [regular+ultralente] predinner) or remained on two ([regular+intermediary] prebreakfast and predinner) subcutaneous injections. They were evaluated after 1 yr of treatment. The major criteria of outcome of efficacy were the concentration of GHb, the frequency of severe hypoglycemia and DKA, and body weight. RESULTS: Of the patients, 82% accepted the three-injection regimen, and 83% accepted the two-injection regimen. At entry into the trial, no significant differences appeared between the two treatment groups nor among patients refusing the allocated regimen. Significant explanatory variables predicting initial diabetes control were duration of disease and adherence to diet. GHb, decreased from 9.8 +/- 0.1 to 9.3 +/- 0.2% (P < 0.05) in the three-injection group, whereas it increased from 9.5 +/- 0.3 to 9.8 +/- 0.3% (P < 0.05) in the two-injection group, resulting in a modest (0.75%) but significant difference (P < 0.05) between GHb change in the two groups. The difference reached 1.4% (P < 0.0002) in patients with GHb > 11.2% at entry. The frequency of hypoglycemia and DKA was similar in the two groups. None of the parameters known to potentially influence glycemic control changed during the trial, and, therefore, the improvement of GHb could be attributed to the pattern of daily insulin distribution per se. CONCLUSIONS: In the general diabetic adolescent population, the efficacy of a three-injection regimen is somewhat superior to that of a conventional two-injection regimen, particularly in patients previously poorly controlled. The acceptability of this regimen being excellent, its increased use should be considered in this age-group.

Adolescent↗
PubMed1993

Hypersensitivity to insulin during remissions in cyclosporin-treated IDDM patients.

OBJECTIVE: To test the sensitivity to insulin in recent-onset IDDM patients, its course according to treatment, and the advent of remissions. RESEARCH DESIGN AND METHODS: The euglycemic hyperinsulinemic clamp was used in 54 recent-onset IDDM patients and 14 healthy control subjects. Patients were tested after 1,2, and 4 wk of treatment with either insulin or insulin plus cyclosporin A, during cyclosporin A-associated long-lasting remissions, and during relapses. RESULTS: Insulin sensitivity was markedly decreased in all patients at onset. It was rapidly restored by insulin therapy, whether immunosuppression was associated with it or not. Insulin sensitivity was even higher than normal in the remission patients, who also were characterized by the reappearance of some endogenous insulin secretion and the sustained normalization of blood glucose profiles. During relapses, the deterioration of the blood glucose profiles was associated with some loss of insulin sensitivity. CONCLUSIONS: Cyclosporin A-associated remissions represent an original situation that associates euglycemia with the persistence of low endogenous insulin secretion. Cyclosporin A by itself had no influence on sensitivity to insulin, but allowed the reappearance of some insulin secretory capacity that contributed, with the improvement of insulin sensitivity, to the development of the diabetes honeymoon. The secretion of endogenous insulin, although lower than normal, was sufficient to secure a high sensitivity to insulin and the maintenance of normal blood glucose profiles, presumably because of the fact that insulin was released directly into the portal vein in these conditions. This metabolic state was precarious: the optimal sensitivity to insulin disappeared in patients who relapsed. These results have important clinical consequences: the preservation of islet residual secretory capacity by the use of newer nontoxic immunosuppressive protocols, combined with a minimal supportive insulin therapy in remission patients, may prolong remissions and maintain an optimal insulin sensitivity.

Adult↗
PubMed1993

["White-coat" effect in 35 consecutive patients with hypertension. Quantification method, role of physician-patient dialogue].

The "white coat" effect, an alarm reaction to the presence of a doctor, is an important cause of blood pressure variability, the frequency, amplitude and mechanisms of which are only partially understood. In order to evaluate these factors, a prospective study was undertaken in 35 consecutive patients referred for assessment of clinical hypertension. The alarm reaction was investigated during the consultation, at the time of interrogation, in periods of silence, in the sitting and upright positions. Twenty-four to forty-eight measurements (average 36.8) of the blood pressure and heart rate were performed in each patient with a Diasys 200 R monitor. The ambulatory period of 3 to 5 hours after the consultation provided 12 to 24 measurements (average 20.7) which were considered to be the reference for comparison with the consultation period. A total of 2,038 measurement were made and analysed. Analysis of variance (GLM) for each patient and for the whole group gave an assessment of the alarm reaction during the patient-doctor dialogue and periods of silence with reference to the ambulatory period. During the ambulatory period, the average and standard deviation for systolic pressure were 134 +/- 0.7 mmHg, and for diastolic pressure 93.1 +/- 0.6 mmHg. These pressures were significantly lower than during the two periods of consultation, with and without dialogue (p < 0.0001). During the consultation, the systolic and diastolic blood pressure values were significantly higher during the dialogue than during the periods of silence (p < 0.0001). During the dialogue, the systolic pressure attained 153.7 +/- 0.7 mmHg and the diastolic pressure: 107.2 +/- 0.6 mmHg.(ABSTRACT TRUNCATED AT 250 WORDS)

Ambulatory Care↗
PubMed1992

[Effect of pregnancy on renal function after transplantation].

Between 1968 and 1991, 36 pregnancies were reported in 28 patients who had undergone kidney transplantation at the Necker hospital, Paris. Pregnancies with favourable graft outcome were compared with those accompanied by significant deterioration of graft function and requiring haemolysis. The risk factors for renal function deterioration during pregnancy in kidney-transplanted women were found to be an initial nephropathy induced or aggravated by a previous pregnancy, an alteration, even mild, of graft function, hypertension, even controlled by treatment, an HLA mismatch and several episodes of acute graft rejection soon after kidney transplantation.

Female↗
PubMed1992

Autosomal dominant polycystic kidney disease with primary hyperaldosteronism.

We report three cases of primary aldosteronism associated with autosomal dominant polycystic kidney disease. The diagnosis of primary hyperaldosteronism was based on the presence of hypokalaemia with excessive urinary potassium excretion and/or the characteristic hormonal changes. Renal function impairment due to autosomal dominant polycystic kidney disease could mask hypokalaemia. The interpretation of adrenal imagery may be hindered by adjacent renal cysts. In one case an adrenal adenoma was detected and surgically removed, with only partial correction of the blood pressure. This could be explained by the persisting underlying autosomal dominant polycystic kidney disease. We conclude that in a hypertensive patient with polycystic kidney disease, extrarenal causes of hypertension may be present.

Adult↗
PubMed1991

Asymmetric synthesis of a precursor for the automated radiosynthesis of S-(3'-t-butylamino-2'-hydroxypropoxy)-benzimidazol-2-[11C]one (S-[11C]CGP 12177) as a preferred radioligand for beta-adrenergic receptors.

S-[1-(2,3-Diaminophenoxy)]-3'-(N-t-butylamino)propan-2'-ol has been synthesized in three steps from 2,3-dinitro-phenol and the chiral auxiliary, S-glycidyl-3-nitrobenzenesulphonate, to provide a precursor for labelling S-(3'-t-butylamino-2'-hydroxypropoxy)-benzimidazol-2-one (S-CGP 12177) with the short-lived positron-emitting radionuclide, carbon-11 (t 1/2 = 20.4 min; beta+ = 99.8%). Reaction of the diamine with [11C]phosgene, itself derived from no-carrier-added cyclotron-produced [11C]methane, provides radiochemically and chemically pure S-[carbonyl-11C]CGP 12177 in greater than 95% enantiomeric excess after HPLC. Automated apparatus is described for safely producing up to 5.9 GBq (160 mCi) of S-[11C]CGP 12177 with high sp. act. (20-40 GBq/mu mol or 0.54-1.08 Ci/mu mol) in a form suitable for human intravenous injection at only 30 min from the end of radionuclide production. S-[11C]CGP 12177 is preferred to the formerly described racemate as a radioligand for the study of beta-adrenergic receptors in vivo by positron emission tomography.

Adrenergic beta-Antagonists↗