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Biomedical subjects

F Carrat

Publications and source records attributed to F Carrat.

At least 19 recordsLinked to original sources

Quality control of leucoreduced cellular blood components in France.

BACKGROUND AND OBJECTIVES: Since 1 April 1998, all cellular blood components in France have been leucoreduced. The current French standard is < 1 x 10(6) white blood cells (WBC) per unit with a 95% confidence that at least 97% of units will meet this standard. MATERIALS AND METHODS: Quality control (QC) data for leucoreduced cellular blood components were collected from the 41 French blood centres over a 5-month period. Conformance to the standard was determined using a non-parametric approach. RESULTS: More than 98% of the 15 286 red cell concentrates and of the 2895 platelet concentrates tested had < 1 x 10(6) WBC per unit. One filtration device gave unsatisfactory results and its use was discontinued. CONCLUSION: This QC survey shows an overall compliance with the standard. The data illustrate the practical value of identifying devices or centres with consistent QC problems.

Adult↗

[D-Dimer determination combined with clinical probability for the diagnosis of leg venous thrombosis].

OBJECTIVE: To evaluate the results of combination of D-Dimer test and simple clinical model for the diagnosis of deep vein thrombosis (DVT). MATERIALS AND METHODS: Inclusion: clinical suspicion of DVT. Non inclusion criteria were Clinical model performed by the referring physician included probability varying from high to low. D-Dimer test was performed by five different rapid techniques. Standard of reference was Doppler ultrasonography (DU) performed by a senior radiologist. RESULTS: Eight hundred and fifty-four DU were performed on a 14 months time period, including 206 suspicion of pulmonary embolism, 109 postoperative time period, 120 non-included or excluded patients, 278 incomplete observations, 141 complete observations. DVT was present in 33 cases and absent in the other 108 cases (prevalence 23%). Sensitivity and negative predictive value of the five tests were between 82 and 97% and 90 et 97%. The most sensitive test had a specificity of 36% and a positive predictive value of 32%. Combination of clinical model and D-Dimer test did not improve the diagnostic accuracy. CONCLUSION: None of the test evaluated in the present study, even when combined with the clinical model results, did allow the exclusion of DVT.

Formycins↗

Severe accidental hypothermia treated in an ICU: prognosis and outcome.

STUDY OBJECTIVES: To assess the characteristics and outcomes of patients admitted to an ICU for severe accidental hypothermia, and to identify risk factors for mortality. METHODS: All consecutive patients admitted to an ICU between January 1, 1979, and July 31, 1998, with a temperature of < or = 32 degrees C were retrospectively analyzed. Rewarming was always conducted passively with survival blankets and conventional covers. Prognostic factors were studied by means of univariate analysis (Mann-Whitney U and chi(2) tests) and multivariate analysis (logistic regression). RESULTS: Forty-seven patients were enrolled (mean +/- SD age, 61.7 +/- 16 years). Five patients had a cardiac arrest before ICU admission. Patient characteristics at ICU admission were as follows: temperature, 28.8 +/- 2.5 degrees C; systolic BP, 85 +/- 23 mm Hg; heart rate, 60 +/- 24 beats/min; Glasgow Coma Scale, 10.4 +/- 3.7; and simplified acute physiology score (SAPS) II, 50.9 +/- 27. Mechanical ventilation was necessary in 23 cases, and 22 patients in shock received vasoactive drugs. The mean length of stay in the ICU was 6.7 +/- 9 days. Eighteen patients (38%) died, but ventricular arrhythmia was never the cause. Univariate analysis identified several prognostic factors (p < 0.05): age (57 +/- 16 years vs 69 +/- 14 years), systolic arterial BP (93 +/- 20 mm Hg vs 71 +/- 21 mm Hg), blood bicarbonate level (23.5 +/- 5.2 mmol/L vs 16.6 +/- 6.2 mmol/L), SAPS II score (35.3 +/- 19.5 vs 72 +/- 21), mechanical ventilation (34% vs 81%), vasopressor agents (42% vs 82%), rewarming time (11.5 +/- 7.2 h vs 17.2 +/- 7 h), and discovery of the patient at home (2.3% vs 54.5%). The initial temperature did not influence vital outcome (28.9 +/- 2.6 degrees C vs 28.6 +/- 2.2 degrees C). Only the use of vasoactive drugs (odds ratio, 9; 95% confidence interval, 1.6 to 50.1) was identified as a prognostic factor in the multivariate analysis. CONCLUSION: Severe accidental hypothermia is a rare cause of ICU admission in an urban area. Its mortality remains high, but there is no overmortality according to the SAPS II-derived prediction of death. Shock, requiring treatment with vasoactive drugs, is an independent risk factor for mortality, while initial core temperature is not. It remains to be determined whether aggressive rather than passive rewarming procedures are better.

Adult↗

[Does Doppler analysis of hepatic venous flow predict increased right atrial pressure and right ventricular dysfunction?].

The aim of this study was to test the hypothesis that Doppler study of hepatic venous flow, reflecting right atrial pressures and right ventricular dysfunction, allows prediction of increased right atrial pressure and right ventricular dysfunction in patients with right ventricular infarction. The authors studied 30 patients (27 men, mean age 54 +/- 12 years) in sinus rhythm with acute inferior myocardial infarction who underwent right heart catheterisation and Doppler echocardiography including recording of regurgitant and hepatic vein flow within 48 hours of hospital admission. Hepatic venous flow was used to measure peak velocity and velocity time integrals (VTI) of the systolic (S), diastolic (D) and atrial (a) contraction waves. The fraction of systolic filling was calculated: VTI S/VTI S + VTI D. The pressure half-time of pulmonary regurgitant flow (PHT IP) was also measured. Using haemodynamic criteria (non-compliant right atrial pressure wave form or right ventricular end diastolic pressure/pulmonary capillary pressure > or = 0.8), patients were divided into two groups: Group 1: right ventricular infarction (VD+, N = 22). Group 2: no right ventricular infarction (VD-, N = 8). No correlation was observed between Doppler parameters of hepatic venous flow and haemodynamic data, in particular right atrial pressure and pressure wave form. Moreover, no statistically significant difference was observed between the two groups with respect to the Doppler parameters derived from hepatic venous flow. On the other hand, the results confirmed good diagnostic performance of Doppler analysis of pulmonary regurgitant flow: sensitivity 80%, specificity 83%, positive predictive value 94%, negative predictive value 55%. The authors conclude that, in patients with acute inferior wall infarction, Doppler analysis of hepatic venous flow does not allow assessment of right atrial pressure or of ischaemic right ventricular dysfunction.

Adult↗

[Comparing two groups of patients].

In medical research, comparing two groups of patients occurs frequently. The basic principles of comparison and the usual statistical tests--according to the types of variables and the choices of sampling methods--are presented. Elements needed for the computation of the size of a comparative study are given.

Humans↗

The effect of ursodeoxycholic acid therapy on liver fibrosis progression in primary biliary cirrhosis.

Ursodeoxycholic acid (UDCA) is the only approved treatment for primary biliary cirrhosis (PBC). However, the benefit from UDCA therapy on the progression of PBC from its early stage towards extensive fibrosis and cirrhosis has not been clearly shown. The aim of this study was to assess the effect of UDCA therapy on liver fibrosis progression in PBC. A Markov model was used to analyze the progression rates between early and late histologic stages in 103 patients with PBC enrolled in a randomized, double-blind, placebo-controlled trial of UDCA. Early stage was defined by the presence of portal and periportal lesions without extensive fibrosis, whereas late stage was defined by the presence of numerous septa, bridging fibrosis, or cirrhosis. A total of 162 pairs of liver biopsy specimens were studied. The model accurately described the observed data. UDCA therapy was associated with a 5-fold lower progression rate from early stage disease to extensive fibrosis or cirrhosis (7% per year under UDCA vs. 34% per year under placebo, P <.002), but was not associated with a significant difference in regression rates (3% per year under both UDCA and placebo). At 4 years, the probability of UDCA-treated patients to remain in early stage disease is 76% (95% confidence interval: 58%-88%), as compared with 29% (15%-52%) in placebo-treated patients. In conclusion, UDCA therapy significantly delays the progression of liver fibrosis in PBC. Markov modeling should prove useful in assessing the efficacy of future medical treatments in clinical trials involving histologic endpoints.

Disease Progression↗

A scale of methodological quality for clinical studies of radiologic examinations.

PURPOSE: To develop and evaluate a scale for assessment of the methodological quality for clinical investigations of radiologic studies. MATERIALS AND METHODS: A scale was developed that included methodological standards compiled from established sources for assessing the methodological quality of study designs in clinical research and characteristics related to biases commonly observed in clinical radiologic research. The scale was composed of 15 standards and was tested with the results of 96 studies on imaging of liver hemangioma. Interrater reliability was measured between two observers by using percentage agreement and kappa statistics. Interrater reliability between two observers for a composite quality index that encompassed the 15 standards was measured with the intraclass correlation coefficient. RESULTS: Agreement between the two observers was almost perfect (kappa value, 0.8-1.0) for 11 standards and substantial (kappa value, 0.74-0.78) for four standards. Agreement between the observers with regard to the composite quality index also was high (intraclass correlation coefficient r, 0.91 [95% CI: 0.87, 0.94]). CONCLUSION: The scale appears to be reliable for the assessment of methodological quality of clinical investigations of radiologic studies.

Hemangioma↗

Comparison of a new method for the direct and simultaneous assessment of LDL- and HDL-cholesterol with ultracentrifugation and established methods.

BACKGROUND: Automated electrophoresis combined with enzymatic cholesterol staining might improve routine assessment of LDL- and HDL-cholesterol (LDLC and HDLC), as an alternative to the Friedewald equation and precipitation. A new method (Hydrasys; SEBIA) that adapts the cholesterol esterase/cholesterol oxidase reaction within urea-free gels was evaluated. METHODS: Fresh sera from 725 subjects (512 dyslipidemics) were analyzed by electrophoresis, in parallel with sequential ultracentrifugation, beta-quantification, calculation, and precipitation. RESULTS: Electrophoresis was linear up to 4 g/L cholesterol, with a detection limit of 0.042 g/L cholesterol/band. Within-run, between-run, between-batch, and between-operator imprecision (CVs) were 1.6%, 2.0%, 1.5%, and 2.7% for LDLC, and 3.9%, 4.3%, 5.5%, and 4.9% for HDLC, and remained unchanged up to 6.3 g/L plasma triglycerides (TGs). Precision decreased with very low HDLC (<0.25 g/L). Serum storage for 3-7 days at +4 or -80 degrees C did not interfere significantly with the assay. Agreement with beta-quantification was stable for LDLC up to 5.07 g/L (r = 0.94), even at TG concentrations >4 g/L (r = 0.91). Bias (2.88% +/- 12%) and total error (7.84%) were unchanged at TG concentrations up to 18.5 g/L. Electrophoresis predicted National Cholesterol Education Program cut-points with <0.04 g/L error, exactly and appropriately classified 79% and 96% of the subjects, and divided by 2.4 (all subjects) and 5.8 (TGs >1.5 g/L) the percentage of subjects underestimated by calculation. One-half of the patients with TGs >4 g/L had LDLC >1.30 g/L. For HDLC, correlation was better with precipitation (r = 0.87) than ultracentrifugation (r = 0.76). Error (-0.10% +/- 26%) increased when HDLC decreased (<0.35 g/L). Direct assessment of the LDLC/HDLC ratio detected 45% more high-risk subjects than the calculation/precipitation combination. CONCLUSIONS: Electrophoresis provides reliable quantification of LDLC, improving precision, accuracy, and concordance over calculation, particularly with increasing plasma TGs. Implementation of methods to detect low cholesterol concentrations could extend the applications for HDLC assessment.

Adolescent↗

Monitoring epidemiologic surveillance data using hidden Markov models.

The analysis of routinely collected surveillance data is an important challenge in public health practice. We present a method based on a hidden Markov model for monitoring such time series. The model characterizes the sequence of measurements by assuming that its probability density function depends on the state of an underlying Markov chain. The parameter vector includes distribution parameters and transition probabilities between the states. Maximum likelihood estimates are obtained with a modified EM algorithm. Extensions are provided to take into account trend and seasonality in the data. The method is demonstrated on two examples: the first seeks to characterize influenza-like illness incidence rates with a mixture of Gaussian distributions, and the other, poliomyelitis counts with mixture of Poisson distributions. The results justify a wider use of this method for analysing surveillance data.

Disease Outbreaks↗

Air pollution and respiratory drug sales in the City of Le Havre, France, 1993-1996.

The aim of this study is to evaluate ambulatory respiratory drug sales data as health indicators for the short-term effects of ambient air pollution in the city of Le Havre. Daily respiratory drug sales data were crossed with daily ambient air concentrations of sulfur dioxide (SO2), nitrogen dioxide (NO2), and black smoke (BS) using an autoregressive Poisson regression model adjusting for time trends, seasonal variations, influenza epidemics, and weather. Relative risks (RR) were expressed for an increase of two standard deviations above the mean of each pollutant. Respiratory drug sales were associated with most pollutants studied with lags varying from 1 to 9 days. For daily mean concentrations of BS, RR = 1.037 (95% confidence interval (CI) 1.009-1.066) for lag 1 and RR = 1.052 (95% CI 1.023-1.081) for lag 8. For daily mean concentrations of N02, RR = 1.033 (95% CI 1.001-1.066) for lag 1 and RR = 1.046 (95% CI 1.014-1.079) for lag 8. RR observed with a daily 1 h maximum of SO2 were RR= 1.027 (95% CI 1.004-1.051) for lag 3 and RR= 1.032 (95% CI 1.009-1.056) for lag 9. Our study concludes that ambulatory respiratory drug sales data could be useful for epidemiological surveillance of air pollutant health effects.

Air Pollution↗

Risk of hepatitis C virus transmission to surgeons and nurses from infected patients: model-based estimates in France.

BACKGROUND/AIM: The aim of this study was to estimate the annual number of cases of hepatitis C virus transmission from infected patients to uninfected surgeons or nurses due to percutaneous injury during invasive procedures. METHODS: The risk of transmission was estimated using a model involving three probabilities: A, that a health care worker sustains at least one percutaneous injury during a procedure; B, that 1 to 10% of patients are seropositive for hepatitis C virus; and C, that infection by this virus is transmitted to the Health Care Worker after such exposure. Probability A was estimated from the results of 2 French multicentric prospective trials. Probability C was estimated from the results of 9 international prospective studies. A ten-fold decreased risk was assumed for surgeons who wear gloves and use solid-bore suture needles. RESULTS: During a single procedure, the estimated probability of hepatitis C virus transmission from an infected patient to an uninfected surgeon ranged from 4.2x10(-5)% to 4.2x10(-4)%, and from 2.98x10(-6)% to 2.98x10(-5)% to an uninfected nurse. For surgeons, the estimated annual cumulative risk of occupational infection ranged from 0.01% to 0.1% (1 in 10000 to 1 in 1000), and for nurses from 0.0054% to 0.054% (1 in 18700 to 1 in 1900). CONCLUSIONS: Between 2 and 21 surgeons out of a total 20000 are estimated to acquire occupationally-related hepatitis C virus infection, and between 16 and 167 nurses out of a total 300000. These estimates strongly justify introducing preventive measures to protect health care workers from bloodborne infection.

France↗

Effects of current and former cigarette smoking on the clinical course of Crohn's disease.

BACKGROUND: Cigarette smoking is associated with a more severe course of Crohn's disease, but individual factors determining this effect are poorly known and it is not clear whether smoking cessation is associated with an improvement in the disease activity. AIM: To assess the factors determining the harmful effect of smoking in individuals with Crohn's disease. METHODS: A total of 622 consecutive patients with Crohn's disease and Crohn's disease activity index <200 were enrolled in a prospective 12-18 month cohort study. Patients were classified as current smokers, former smokers, or non-smokers. Alcohol consumption, oral contraceptive use, body mass index, and blood lipid levels were also recorded. The main outcome measure was the rate of flare-up. RESULTS: A total of 139 current smokers (46%) developed a flare-up, vs. 79 non-smokers (30%) and 13 former smokers (23%). The relative risk of flare-up adjusted for confounding factors was 1.35 (1.03-1.76) in current smokers. This risk was increased in patients with previously inactive disease and in those who had no colonic lesions. It became significant above a threshold of 15 cigarettes per day. Former smokers behaved like non-smokers. Obesity, dyslipidaemia, and alcohol consumption had no significant effect. CONCLUSIONS: Current smoking, particularly heavy smoking, markedly increases the risk of flare-up in Crohn's disease. Former smokers have a risk similar to that of non-smokers.

Adult↗

Evaluation of clinical case definitions of influenza: detailed investigation of patients during the 1995-1996 epidemic in France.

Using clinical predictors, we evaluated clinical case definitions of influenza during the 1995-1996 outbreak in France. Thirty-five general practitioners collected virological specimens and clinical data. Predictors of influenza virus infection were selected with logistic regression models. The results varied with the influenza virus subtype: temperature of >38.2 degrees C, stiffness or myalgia, rhinorrhea, and cough were predictive of influenza A/H3N2, whereas fatigue, lacrimation or conjunctival injection, and the absence of stiffness or myalgia were predictive of influenza A/H1N1. On the basis of this analysis and data from the literature, 12 clinical case definitions were evaluated for their abilities to diagnose influenza virus infection. They were associated with positive predictive values of 27% to 40% and negative predictive values of 80% to 91%. We conclude that focused studies evaluating clinical case definitions of influenza with use of subsets of patients should accompany population-based disease surveillance for optimal estimates of the disease burden associated with influenza epidemics.

Disease Outbreaks↗

Oral contraceptive use and the clinical course of Crohn's disease: a prospective cohort study.

BACKGROUND: Women with Crohn's disease are usually advised not to take oral contraceptives, but, unlike smoking, there is no clear association between current oral contraceptive use and more severe disease. AIM: To assess the effect of oral contraceptive use on the clinical course of Crohn's disease. PATIENTS: 331 women, aged 16-50 years, with Crohn's disease and Crohn's disease activity index <200, were enrolled consecutively during a one year period. Patients were classified at inclusion as oral contraceptive users or non-users and smokers or non-smokers. METHODS: A prospective 12-18 month cohort study was used. The main outcome measures were flare up rate and time to flare up. RESULTS: In total, 134 women used oral contraceptives, in most cases low oestrogen formulations. During the study period, 61 oral contraceptive users (46%) developed a flare up, compared with 85 non-users (43%). The hazard ratio for oral contraceptive use was 1.11 (95% confidence interval 0.80 to 1.55). Variables associated with flare up were smoking status, recently active disease, baseline Crohn's disease activity index, and presence of anoperineal lesions. The same results were obtained when the analysis was restricted to patients eligible for a relapse prevention trial. CONCLUSION: Unlike smoking, oral contraceptives have no effect on Crohn's disease activity.

Adolescent↗

Effect of indinavir on HIV-related wasting.

OBJECTIVE: To study the effect of the protease inhibitor indinavir on body weight and body composition of subjects with HIV-related wasting. DESIGN: Prospective measurement of body weight in patients who had wasting and were treated with indinavir. A subgroup of 16 representative patients also underwent a metabolic study that included measurements of body composition (skinfolds and bioelectrical impedance) and food intake. Seven from this subgroup who did not have chronic diarrhoea also underwent indirect calorimetry for measurement of resting energy expenditure; the nine patients with wasting and chronic diarrhoea had measurements of faecal losses and intestinal permeability using the lactulose-mannitol test. SETTING: A tertiary care university hospital. PATIENTS: Two hundred and fourteen HIV-infected patients with wasting (less than 95% of usual body weight) had their body weight measured at day 0; 186 patients had a second body weight measurement within the first 100 days of treatment, and 160 patients were weighed a third time, at a median of 176 days. RESULTS: Body weight increased significantly (P < 0.0001) during treatment, whatever the degree of weight loss at baseline. After a median of 176 days on treatment, body weight had increased in 119 out of the 160 patients followed (74.4%; mean weight gain, 6.3+/-SD 3.8 kg; range, 1-18 kg), had not changed in 13 (8.1%) and had fallen in 28 (17.5%; mean weight loss, 4.2+/-3.0 kg; range, 1-12 kg), relative to baseline. Overall, 119 out of the 214 patients (55.6%) from the initial population gained weight. Fat mass, fat-free mass and body cell mass increased significantly in the 16 patients who underwent metabolic studies, together with energy, protein and lipid intake. In the patients with chronic diarrhoea, intestinal permeability improved but there was no change in intestinal losses. In patients who had wasting but not chronic diarrhoea, resting energy expenditure did not change significantly. Body weight changes correlated with changes in the CD4+ cell count (r = 0.882; P = 0.00001) and, to a lesser extent, with changes in the viral load (r = -0.466; P = 0.047). CONCLUSION: Indinavir significantly improved the nutritional status of these patients with HIV-related wasting.

Adult↗

Factors of weight loss in patients with HIV and chronic diarrhea.

Weight loss is significant in patients with HIV and chronic diarrhea. The aim of our study was to test for the links between weight loss, the level of food intake, and the severity of diarrhea and nutrient malabsorption. One hundred and sixteen patients with HIV and chronic diarrhea underwent a standardized gastrointestinal and nutritional evaluation, which included a questionnaire on diarrhea, a prospective estimation of food intake, a measurement of blood parameters and fecal lipid and nitrogen outputs, a stool examination for bacteria and parasites, and upper and lower digestive tract endoscopy. Diarrhea resulted from an infection by Cryptosporidia, Microsporida, or other pathogens in 22%, 20%, and 13% of the patients, respectively. Diarrhea appeared idiopathic in 45% of the patients. A significant negative correlation existed between the severity of weight loss and the levels of nutrient intake (p < .005), and a significant positive correlation between the severity of weight loss and stool frequency (p < .01). Multiple linear regression identified low caloric intake and high stool frequency as predictive of weight loss. No significant correlation was found between weight loss and the parameters of malabsorption, either by bivariate study or multiple regression. These results suggest that, in patients with HIV and chronic diarrhea, the degree of wasting is significantly related to the levels of dietary intake and the clinical severity of diarrhea, but not to the extent of nutrient malabsorption.

AIDS-Related Opportunistic Infections↗

[Transmission modes of hepatitis C virus].

SITUATION IN FRANCE: The prevalence of hepatitis C virus (HCV) infection in the French population is estimated at 1%, a level similar to that in other western countries. USUAL CONTAMINATION ROUTES: Epidemiological studies, together with gene typing, have made it possible to distinguish transmission modes. A history of intravenous drug abuse or transfusion is found in 60 to 80% of all subjects infected by the HCV. Other documented modes of contamination include hemodialysis, organ transplantation, accidental occupational-related puncture and mother-infant transmission. OTHER ROUTES: Sexual or intra-familial nonsexual transmission is uncommon and related to the length of exposure and the stage of HCV infection in the "source" subjects. Cases of HCV transmission have been reported during medical procedures. Currently the mode of of transmission is unknown in 20 to 40% of the cases.

Blood Transfusion↗

Overexpression of stromelysin-3, BM-40/SPARC, and MET genes in human esophageal carcinoma: implications for prognosis.

Molecular markers can improve staging and predict aggressive clinical behavior in esophageal cancer, thus helping to define appropriate therapeutic protocols and to identify patients who will benefit from surgery. We therefore characterized, by Northern blot and/or immunohistochemistry, the relative expression of three effectors involved in the invasion, angiogenesis, and dissemination of tumor cells in esophageal cancer versus nontumoral mucosae: (a) stromelysin-3 (ST3), a member of the metalloproteinase family; (b) basement membrane 40/secreted protein acidic and rich in cysteine (BM-40/SPARC), an extracellular matrix-associated protein involved in angiogenesis; and (c) the hepatocyte growth factor receptor MET, which triggers the scattering of epithelial cells. Results were analyzed in relation to clinicopathological parameters (cpTNE) including tumor size (T), lymph node status (N), periesophageal tissue invasion (E), disease recurrence, and overall survival. The ST3, BM-40/SPARC, and MET genes were found to be overexpressed in tumor samples compared to control mucosa. BM-40/SPARC and MET mRNA levels were not linked to any one of the cpTNE, indicating that this overexpression occurs at an early stage of neoplastic progression. In contrast, ST3 expression, identified by immunohistochemistry in fibroblastic cells surrounding neoplastic islets, correlated with tumor size and periesophageal tissue invasion. Of the 36 patients studied, those with high ST3 levels had shorter disease-free survival than those with low levels, but there was no relationship between the cpTNE and disease recurrence or survival. Our study demonstrates that ST3, BM-40/SPARC, and MET are involved in different steps of esophageal carcinogenesis and that ST3 overexpression is a marker of aggressive clinical behavior. We conclude that in esophageal cancer, ST3 might help to assess survival and the risk of recurrence after surgical resection.

Adenocarcinoma↗