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Biomedical subjects

P Landais

Publications and source records attributed to P Landais.

At least 55 records · Page 3Linked to original sources
PubMed1996

Talking effect and white coat phenomenon in hypertensive patients.

Both white coat effect (the tendency of blood pressure to rise during a medical visit) and talking effect were analyzed in 42 patients with essential hypertension. Blood pressure was measured during the clinic visit and over the subsequent 24-hour ambulatory period, with the physician performing 49 +/- 4 measurements for each patient. Three silent periods and two talking periods (stress and relaxation) were randomly allocated in a crossover design and studied, using analysis of variance. During the initial 11-minute silent period, systolic/diastolic blood pressures increased by 6 mm Hg/5 mm Hg. During the subsequent talking periods, these variations were significantly greater: +22 mm Hg/+17 mm Hg. Measures of systolic/diastolic blood pressure were higher during stressful talking than during relaxed talking. The talking and its emotional contents seemed to explain 70% of the white coat phenomenon. To minimize the white coat phenomenon in the clinic, physicians, nurses, and clinicians are advised to measure blood pressure during an initial period of silence.

Communication↗
PubMed1996

Prognostic factors in acute renal failure due to sepsis. Results of a prospective multicentre study. The French Study Group on Acute Renal Failure.

BACKGROUND: Sepsis is a major cause of acute renal failure in hospital patients, but its incidence and the associated prognostic factors have rarely been assessed prospectively by multivariate analysis. METHODS: We conducted a prospective 6-month study in 20 multidisciplinary intensive care units to assess the prognosis of patients hospitalized with acute renal failure due to sepsis. Sepsis syndrome and septic shock were defined according to the criteria of the Society of Critical Care Medicine Consensus Conference. Severity scoring indexes (SAPS, APACHE II, and organ system failure (OSF)) were measured on ICU admission and on inclusion. The end-point was hospital mortality. RESULTS: Acute renal failure had a septic origin in 157 patients (Group 1), comprising 68 with septic shock and 89 with sepsis syndrome, and did not result from infection in 188 patients (Group 2). Patients with septic acute renal failure were older (mean age: 62.2 versus 57.9 years, P<0.02) and had on inclusion a higher SAPS (19.3 versus 16.1, P<0.001), APACHE II (29.6 versus 24.3, P<0.001), and OSF (2.07 versus 1.52, P<0.001) than patients with non-septic acute renal failure. They had a higher need for mechanical ventilation (69.1% versus 47.3%, P<0.001), and acute renal failure was more often delayed during the ICU stay than was present on admission (47.7% versus 32.4% respectively, P<0.005). Hospital mortality was higher in patients with septic acute renal failure (74.5%) than in those whose renal failure did not result from sepsis (45.2%, P<0.001). Mortality was influenced by the presence of a septic shock (79.4%) or of a sepsis syndrome on inclusion (70.8%). Using a stepwise logistic regression model, sepsis was an independent predictor of hospital mortality (OR, 2.51; 95% CI, 1.44-4.39) as well as a delayed occurrence of acute renal failure, oliguria, an altered previous health status hospitalization prior to ICU, need for mechanical ventilation, age and severity scoring indexes on inclusion. In total patients, mortality was higher in dialyzed than in non-dialyzed patients (P<0.001), and in those treated by continuous compared to intermittent techniques (P<0.01). Patients dialyzed with biocompatible membranes had a lower mortality than those treated with cellulose membranes (P<0.005). CONCLUSIONS: Patients with acute renal failure due to sepsis have a worse prognosis than those with non-septic acute renal failure. Sepsis and the above-defined predictive factors are to be considered in studies on prognosis of ARF patients. Our results suggest that the use of biocompatible membranes may reduce significantly mortality in these patients.

Acute Kidney Injury↗
PubMed1996

Perfusion-MVO2 mismatch during inotropic stress in CAD patients with normal contractile function.

With the use of[11C]acetate, positron emission tomography (PET) permits exploration of myocardial blood flow (MBF) and oxidative metabolism (MVo2) coupling. PET imaging was performed at rest and under dobutamine infusion in 8 normal subjects and 10 coronary artery disease (CAD) patients with significant single-vessel left anterior descending (LAD) stenosis (> 70%) and normal regional left contractile function at rest. Resting MBF and MVo2 were similar in remote and LAD regions of normal subjects and patients. During dobutamine infusion, MBF and myocardial flow reserve were lower in LAD regions of patients compared with remote regions (MBF: 1.49 +/- 0.42 and 2.06 +/- 0.57 ml.g-1.min-1, P < 0.01; reserve: 1.73 +/- 0.59 and 2.14 +/- 0.47, P < 0.01, respectively), whereas MVo2 expressed as kmono (an index of MVo2) and metabolic reserve were similar (kmono: 0.106 +/- 0.021 vs. 0.107 +/- 0.017 min-1; reserve: 1.88 +/- 0.32 vs. 1.98 +/- 0.37, respectively). This is the first human study showing that, in normal contractile regions at rest but perfused by stenosed artery, a disparate rise in MVo2 relative to the rise in myocardial perfusion occurs during increased cardiac work induced by dobutamine. This flow-metabolism uncoupling probably reflects an increase in O2 extraction.

Adult↗
PubMed1995

Allele doses of apolipoprotein E type epsilon 4 in sporadic late-onset Alzheimer's disease.

Apoliprotein E, type epsilon 4 allele (ApoE-epsilon 4) is associated with late-onset sporadic Alzheimer's disease (AD). We have found that the cumulative probability of remaining unaffected over time decreases for each dose of ApoE-epsilon 4 in sporadic, late-onset French AD. The effect of genotypes on age at onset of AD was analyzed using the product limit method, to compare unaffected groups during aging.

Age of Onset↗
PubMed1995

Hepatitis C virus type 1b (II) infection in France and Italy. Collaborative Study Group.

OBJECTIVE: To analyze the distribution of hepatitis C virus (HCV) genotypes among patients positive for antibody to HCV (anti-HCV) according to age, severity of liver disease, and duration of infection; to investigate the influence of HCV genotypes on response to interferon-alpha therapy; and to study HCV viremia levels in relation to genotypes and severity of liver disease. DESIGN: Cross-sectional study. SETTING: 3 university hospitals and 2 research units. PATIENTS: 3 groups of French and Italian patients with chronic HCV infection and detectable serum HCV RNA: Group 1 included 35 patients with hepatocellular carcinoma; group 2, 71 patients with cirrhosis who did not have hepatocellular carcinoma; and group 3, 114 patients with chronic active hepatitis. 106 of the patients with chronic hepatitis or cirrhosis were treated with interferon-alpha (3 MU subcutaneously 3 times/wk for > or = 6 months). MEASUREMENTS: Genotyping by polymerase chain reaction with capsid-specific primers; serum HCV RNA by branched DNA (bDNA) signal amplification. RESULTS: Hepatitis C virus genotype 1b (II) was the most prevalent genotype (61.8%). In a univariate analysis, it was associated with older age (< 40 years, 47.4%; > or = 60 years, 80.4%; P = 0.001), longer duration of disease (< or = 10 years, 40.4%; > or = 20 years, 86.7%; P = 0.005), and cirrhosis with or without hepatocellular carcinoma (78.4% compared with 53.8% for chronic hepatitis; P < 0.001). Viremia levels did not differ between patients infected with HCV type 1b (II) and those infected with other HCV genotypes. Patients with HCV type 1b (II) responded to interferon-alpha therapy significantly less than did patients with other HCV genotypes (P = 0.01). In a multivariate analysis, age and cirrhosis were independently associated with HCV genotype 1b (II). Genotype and HCV viremia level were independent predictors of response to interferon-alpha therapy. CONCLUSIONS: The prevalence of HCV genotypes in French and Italian patients has been changing; the prevalence of HCV type 1b (II) infection has progressively decreased, although it still accounts for most HCV-related cirrhosis and hepatocellular carcinoma. High HCV viremia levels and HCV genotype type 1b (II) are independent predictors for poor response to interferon-alpha therapy and should be considered in the management of patients with HCV infection.

Adult↗
PubMed1995

Evaluation of severity scoring systems in ICUs--translation, conversion and definition ambiguities as a source of inter-observer variability in Apache II, SAPS and OSF.

OBJECTIVE: To explore translation, conversion and definition ambiguities, when using severity scoring systems in patients admitted to intensive care units (ICUs). DESIGN: A prospective study of the prognosis of acute renal failure in ICUs. SETTING: The study was conducted in 20 French ICUs. PATIENTS: 360 patients presenting with severe acute renal failure were studied during their ICU stay. MEASUREMENTS AND RESULTS: The inter-observer variability of Apache II (acute physiology and chronic health evaluation), SAPS (simplified acute physiology score), and OSF (organ-system failure) was considered. For Apache II, we explored the uncertainty of measurements arising from conversion into SI units, the rounding procedures used for the non-inclusive intervals defined for quantitative parameters such as age, mean arterial pressure (MAP) or serum creatinine, the absence of definition of acute renal failure (ARF) and its consequence on doubling serum creatinine values, and the absence of guidelines in the case of spontaneous ventilation when arterial blood gases (ABG) and forced inspiratory oxygen (FIO2) were not measured. The resulting variability was evaluated, calculating the lowest and the highest value of the scoring system for each patient. The mean difference by patient was greater than 1.5 (p < 0.0001). Other examples were presented and discussed for SAPS and OSF. CONCLUSIONS: Translation, conversion and definition ambiguities are a source of inter-observer variability and increase the risk of classification and/or selection biases. This gives rise to particular concern in the design and analysis of multicenter trials of meta-analysis, and improvement of these scoring systems should be envisaged in the future.

APACHE↗
PubMed1995

Prognosis of patients with nonmalignant chronic intestinal failure receiving long-term home parenteral nutrition.

BACKGROUND/AIMS: Long-term survival of patients with intestinal failure requiring home parenteral nutrition (HPN) has been only partly shown. Therefore, we described the survival of these patients and explored prognosis factors. METHODS: Two hundred seventeen noncancer non-acquired immunodeficiency syndrome adult patients presenting with chronic intestinal failure enrolled from January 1980 to December 1989 in approved HPN programs in Belgium and France; prognosis factors of survival were explored using multivariate analysis. Data were updated in March 1991; not one of the patients was lost to follow-up. RESULTS: Seventy-three patients died during the survey, and the mortality rate related to HPN complications accounted for 11% of deaths. Probabilities of survival at 1, 3, and 5 years were 91%, 70%, and 62%, respectively. Three independent variables were associated with a decreased risk of death: age of patients younger than 40 years, start of HPN after 1987, and absence of chronic intestinal obstruction. In patients younger than 60 years of age included after 1983 with a very short bowel, who could represent suitable candidates for small bowel transplantation, the 2-year survival rate was 90%, a prognosis that compared favorably with recent reports of survival after small bowel transplantation. CONCLUSIONS: HPN prognosis compares favorably with recent reports of survival after small bowel transplantation.

Adolescent↗
PubMed1995

Malignancies after renal transplantation: the EDTA-ERA registry experience. European Dialysis and Transplantation Association-European Renal Association.

The incidence of malignancies in recipients of renal transplants was compared to that in non-grafted patients on maintenance dialysis as reported to the EDTA-ERA Registry and in the general population as recorded by the cancer registries of England and Wales, of Sweden, of the (former) German Democratic Republic, and of Lombardy and Varese in Northern Italy. For tumours known to be associated with immunosuppression, namely Kaposi's sarcoma, non-Hodgkin lymphoma and the common malignancies of the skin (except melanoma), an increased incidence was confirmed for the transplanted population. Thyroid carcinoma and hepatoma were found to be more frequent in non-grafted patients on dialysis as well as after renal transplantation. An increased incidence of cancer of the cervix and of the body of the uterus was recorded only for young cohorts with a functioning graft but not for women after menopause. Most of the other malignancies had similar incidences in grafted and non-grafted populations which did not differ from those in the general populations of the cancer registries except cancer of the colon which was slightly more frequent, particularly at 10-20 years after the first transplant operation. Survival after diagnosis of cancer at the most frequent sites, such as bronchopulmonary, breast, oesophagogastric and colorectal cancer, did not differ between non-grafted patient groups on dialysis and those who developed the tumour while carrying a functioning renal transplant.(ABSTRACT TRUNCATED AT 250 WORDS)

Age Distribution↗
PubMed1995

Survival modelling in kidney transplantation: hazard rates of graft loss. Transplant Working Group of the Registry Committee of the European Dialysis and Transplantation Association-European Renal Association (EDTA-ERA).

Mathematical modelling of survival data provides long-term projection of graft survival and allows evaluation of the impact of several variables on graft outcome. We analysed 52,315 first cadaveric grafts performed between 1971 and 1985 and reported to the EDTA Registry. We quantified the risk of graft loss using the hazard rates. The hazard function provides the magnitude of the risk of graft loss at a given time post-transplantation. For the 1971 and the 1985 cohorts, the risk of graft loss at 1 month posttransplantation was 143 and 53 per 1000 patient-months, respectively. At 1 year it was 5 and 2.4 per 1,000, respectively. The hazard function thus allowed quantification of the magnitude of the risk of graft loss and its evolution along with time. At 5 years posttransplantation, the risk of graft loss was close to 1 per 1,000, whatever the cohort considered, quantifying the lack of improvement of graft losses in the long term since the early 1970s. It was also possible to evaluate the composition of the risk and to explore the respective influence of graft failure and of patient death.

Aged↗
PubMed1994

Randomised controlled trial of enalapril and beta blockers in non-diabetic chronic renal failure.

OBJECTIVE: To compare the ability of angiotensin converting enzyme inhibitors and beta blockers to slow the development of end stage renal failure in non-diabetic patients with chronic renal failure. DESIGN: Open randomised multicentre trial with three year follow up. SETTING: Outpatient departments of six French hospitals. PATIENTS: 100 hypertensive patients with chronic renal failure (initial serum creatinine 200-400 mumol/l. 52 randomised to enalapril and 48 to beta blockers (conventional treatment). INTERVENTIONS: Enalapril or beta blocker was combined with frusemide and, if necessary, a calcium blocker or centrally acting drug in patients whose diastolic pressure remained above 90 mm Hg. RESULTS: 17 patients receiving conventional treatment and 10 receiving enalapril developed end stage renal failure. The cumulative renal survival rate was significantly better in the enalapril group than in the conventional group (P < 0.05). The slope of the reciprocal serum creatinine concentration was steeper in the conventionally treated patients (-6.89 x 10(-5)l/mumol/month) than in the enalapril group (-4.17 x 10(-5)l/mumol/month; P < 0.05). No difference in blood pressure was found between groups. CONCLUSION: In hypertensive patients with chronic renal failure enalapril slows progression towards end stage renal failure compared with beta blockers. This effect was probably not mediated through controlling blood pressure.

Acebutolol↗
PubMed1994

Bone marrow transplantation (BMT) in Europe for primary immunodeficiencies other than severe combined immunodeficiency: a report from the European Group for BMT and the European Group for Immunodeficiency.

Bone marrow (BM) transplantations performed between 1977 and 1991 at 13 European centers in 149 patients with 11 different primary immunodeficiency (ID) diseases (excluding severe combined immunodeficiency) were analyzed retrospectively. Overall survival among recipients of HLA genetically identical BM (n = 56) was 66%. Since October 1985, the date of a previous survey, a significant improvement in survival has been achieved in most ID diseases (overall survival, 81.5% v 51.7%; P < .01), primarily because of a decrease in the frequency of infectious complications. In long-term survivors, disease correction is excellent, with minimal sequelae in most patients. In 22 patients who received closely matched BM (ie, from phenotypically identical related donors, matched unrelated donors, or one HLA-ag-mismatched related donors), the survival rate (45.5%) was not significantly better than among 71 recipients of BM with 2 or 3 mismatched HLA antigens (38%). In the latter group, favorable outcome was associated with younger age, with transplantation since October 1985 (47% v 25%; P < .0001), and with a diagnosis of leukocyte adhesion deficiency. The improvement in outcome was mainly because of a higher engraftment rate and a decrease in the frequency of infections, although Epstein-Barr virus-induced B-lymphocyte proliferative disorders occurred in 16 patients (mainly those with Wiskott-Aldrich syndrome), 10 of whom died. The improvement in engraftment corresponded to the introduction of treatment in vivo with anti-LFA-1 antibody to prevent rejection of T-cell-depleted grafts (74% engraftment and 45% survival in 38 treated patients versus 37.5% and 21%, respectively, in 24 untreated patients.

Adult↗
PubMed1994

Effects of GABAA receptors activation on brain glucose metabolism in normal subjects and temporal lobe epilepsy (TLE) patients. A positron emission tomography (PET) study. Part I: Brain glucose metabolism is increased after GABAA receptors activation.

Though gamma-aminobutyric acid (GABA) is the major inhibitory neurotransmitter in the human central nervous system, the metabolic response to GABA system activation remains imperfectly known. We studied in vivo with positron emission tomography (PET) the variations of glucose metabolism in the human brain after stimulation of the GABAA receptors by systemic administration of the specific GABAA agonist, 4,5,6,7-tetrahydroisoxazolo[5,4-c]pyridin-3-ol (THIP). These investigations were performed in three normal volunteers and as part of presurgical evaluation for temporal lobe epilepsy in six patients. While clinical and electroencephalographic (EEG) monitoring showed a sedative effect and sleepiness after THIP administration, glucose metabolism was paradoxically increased in grey matter structures, which are known to have a high density of GABAA receptors. These findings suggest that the pharmacological activation of GABA pathways, although inhibitory and producing a decrease of vigilance, increases the energetic demand at least during a phase of GABA agonist action, probably at the synaptic or at the glial cell level.

Adult↗
PubMed1994

Effects of GABAA receptors activation on brain glucose metabolism in normal subjects and temporal lobe epilepsy (TLE) patients. A positron emission tomography (PET) study. Part II: The focal hypometabolism is reactive to GABAA agonist administration in TLE.

Positron emission tomography (PET) using [18F]fluorodeoxyglucose (FDG) was used to study the metabolic response of focal hypometabolism to the administration of a specific GABAA agonist (4,5,6,7-tetrahydroisoxazolo[5,4-c]pyridin-3-ol), THIP, in six temporal lobe epilepsy (TLE) patients. After THIP injection, the increase of glucose metabolism in the hypometabolic focus was larger than the mean increase reported in the whole brain (Part I; Epilepsy Res., 19 (1994) 45-54). Within the hypometabolic focus, this increase was significantly higher in regions with the lowest basal metabolic level. This metabolic response in the hypometabolic focus, observed in the absence of any epileptic discharge during FDG accumulation and PET data acquisition, suggests that GABAA receptors are up-regulated or, at least, preserved in TLE.

Adult↗
PubMed1994

Absence of association between HLA antigens and chronicity of viral hepatitis in haemodialyzed patients.

The role of HLA antigens in the chronicity of viral hepatitis is still being debated. We analyzed the relation between HLA status and viral hepatitis in 558 consecutive haemodialyzed patients who underwent kidney transplantation. HLA A, B, DR status, ABO-Rh blood group, duration of haemodialysis, and number of blood units transfused during the dialysis period were known for all patients. Serological status for hepatitis B virus and hepatitis C virus and results of liver biopsies were available in 495, 300 and 316 patients, respectively. After correction for the number of tests performed, frequencies of HLA antigens did not differ significantly for: 1. hepatitis B virus infection (compared to HBsAg-positive and anti-HBc and/or anti-HBs-positive nonvaccinated patients); 2. hepatitis C virus infection (compared to anti-HCV-negative and -positive patients); 3. histopathological status (compared to patients who had chronic viral hepatitis and those who did not). These results suggest that there is no evidence for a significant role of a particular HLA antigen in the development of chronic viral hepatitis in haemodialysis patients with similar underlying immunosuppression and exposure to infection by hepatotropic viruses.

Adult↗
PubMed1994

Variation of rheological properties of the human rectal wall with distending volume.

Pressure-relaxation curves of in vivo human rectal wall were studied in 30 normal children for 5 volumes of distension, 10-50 ml, to define the conditions of application of the quasi-linear viscoelastic law. Three normalization methods were compared: the use of the maximum pressure of the curve, the use of the first measured point after the rectal distension, and the use of the passive state defined as the inferior envelope of the experimental curve. Analysis of variance with repeated measures was used for data analysis. It was shown that: i) the first relaxation curve, corresponding to a 10-ml distension volume, was significantly different from the other curves (p < 0.0001); ii) the quasi-linear viscoelastic law could be applied to the in vivo determination of the mechanical properties of the rectal wall, when considering the mean level of the measured points; and iii) the shapes of the experimental curves at different level of distension were significantly different (p < 0.0001). We conclude that the hypothesis of quasi-linearity is appropriate, in a first approximation, as a model of rheological properties of the rectal wall.

Adolescent↗