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C Colin

Publications and source records attributed to C Colin.

At least 37 records · Page 2Linked to original sources
PubMed2003

The role of evoked potentials (EPs) in the assessment of the human central auditory nervous system (CANS).

This paper presents an overview of the use of EPs in the assessment of the CANS. Emphasis is laid on recent developments and research efforts centered on appraising how the auditory neural code is processed by the central pathways. It is shown how, in addition to their classical site-of-lesion testing role, EPs can, especially when combined with ecological (mostly speech-like) stimuli, yield highly valuable information on the neurophysiological processes leading to the perception of auditory objects as well as speech. Special space is devoted to the Mismatch Negativity that currently provides the only objective measure of the accuracy with which the CANS detects auditory and phonetic contrasts.

Auditory Diseases, Central↗
PubMed2002

[Worsening of heart failure during hospital course in myocardial infarction is a factor of poor prognosis. Apropos of a prospective cohort study of 2,507 patients hospitalized with myocardial infarction: the PRIMA study].

BACKGROUND: Worsening of heart failure in patients with myocardial infarction is seldom studied, elderly patients often are not included, and multivariate analysis is uncommon. AIMS: The prospective PRIMA study (Prise en charge de l'Infarctus du Myocarde Aigu; management of acute myocardial infarction) sought to determine the incidence of heart failure worsening, its risk factors, and its prognostic importance in patients with myocardial infarction, regardless of age and hospital facilities, in the "real world" in a region in France, using multivariate analysis. METHODS: Data were prospectively collected in all patients with myocardial infarction admitted in all hospitals in three departments in the Rhône-Alpes region in France between September 1, 1993 and January 31, 1995. RESULTS: Among 2,507 patients, 33% were in Killip classes II-IV at admission. Four hundred and sixteen patients (17%) had worsening of Killip class during the first five days. In-hospital mortality (overall: 14%) increased dramatically with Killip class at admission (9% in class I; 62% in class IV) and with worsening of Killip class during the first five days (36% vs 8% if no worsening). In multivariate analysis, older age, diabetes mellitus and anterior Q-wave myocardial infarction were significant predictors of Killip class at admission and of its worsening. The significant predictors of in-hospital mortality were older age, Killip class III at admission and worsening of Killip class during the first five days. CONCLUSION: This large, unselected cohort revealed that among patients with myocardial infarction, heart failure and its worsening are frequent, especially in the elderly, and dramatically worsen the in-hospital mortality.

Aged↗
PubMed2002

Method of correction to assess the number of hospitalized incident breast cancer cases based on claims databases.

Estimations of the number of hospitalized incident cancer cases show biases when claims databases are used. This is due to false reports of incident cancer because of a lack of specificity, and because of unrecorded cancers resulting from a lack of sensitivity. We present a statistical method to provide corrected estimations. This method is based on a two-phase study design using an external data set for sensitivity and specificity estimates. Inaccuracy of the corrected number of hospitalized incident cancer cases was assessed by a credibility interval determined by a Bayesian approach using a Monte Carlo method. Based on the population hospitalized in a large group of French University hospitals, 334 women were identified in the French claims database as having potential incident cases of breast cancer in 1997. According to our method, the corrected number was 565 (550-580). In absence of hospital-based cancer registries, our approach provides estimates and credibility intervals, and has many potential applications in defining hospital policies with its applicability to other diseases.

Breast Neoplasms↗
PubMed2002

Declared hepatitis C screening strategies in blood recipients in French hospitals.

AIMS OF THE STUDY: In spite of official recommendations and measures in France, screening strategies of hepatitis C performed in the field of transfusion are not clearly known. The aim of this study is to describe the screening strategies before and after the current year of the transfusion in blood recipients in several French medical departments and hospitals. MATERIALS AND METHODS: A qualitative study using the key informant technique was carried out. A sample of 179 departments and 64 hospitals in charge of patients transfused with low or high-volumes of homologous blood products was constituted. The key informants were asked about the number of homologous blood products, the number of recipients transfused in the hospital, the volume of transfusion performed, the existence of a single defined screening strategy, the time of prescription of the biological tests (before or after transfusion), the tests performed on cryopreserved blood samples, and the indications of the transfusion. RESULTS: The main screening strategy was HCV serology (second or third generation of enzyme immunoassays) with transaminase assessments before and after transfusion in 14% of the declared screening strategies. Screening tests were more frequently prescribed after transfusion, in at least 64% of the declared screening strategies according to the volume of transfusion. HCV serology was the common test prescribed in 61 and 50% of the screening strategies for low and high-volume transfusion respectively. The screening strategies showed a large heterogeneity combining HCV serology, transaminase assessment, before or after transfusion. CONCLUSION: A great heterogeneity of screening strategies was found. The most frequent was HCV serology with transaminase assessment before and after transfusion. Recommendations on screening strategies are needed in order to limit practice heterogeneity. This study will help building a cost-efficacy model in order to guide public health decision making.

Alanine Transaminase↗
PubMed2002

Mismatch negativity evoked by the McGurk-MacDonald effect: a phonetic representation within short-term memory.

OBJECTIVES: The McGurk-MacDonald illusory percept is obtained by dubbing an incongruent articulatory movement on an auditory phoneme. This type of audiovisual speech perception contributes to the assessment of theories of speech perception. The mismatch negativity (MMN) reflects the detection of a deviant stimulus within the auditory short-term memory and besides an acoustic component, possesses, under certain conditions, a phonetic one. The present study assessed the existence of an MMN evoked by McGurk-MacDonald percepts elicited by audiovisual stimuli with constant auditory components. METHODS: Cortical evoked potentials were recorded using the oddball paradigm on 8 adults in 3 experimental conditions: auditory alone, visual alone and audiovisual stimulation. Obtaining illusory percepts was confirmed in an additional psychophysical condition. RESULTS: The auditory deviant syllables and the audiovisual incongruent syllables elicited a significant MMN at Fz. In the visual condition, no negativity was observed either at Fz, or at O(z). CONCLUSIONS: An MMN can be evoked by visual articulatory deviants, provided they are presented in a suitable auditory context leading to a phonetically significant interaction. The recording of an MMN elicited by illusory McGurk percepts suggests that audiovisual integration mechanisms in speech take place rather early during the perceptual processes.

Acoustic Stimulation↗
PubMed2002

Electrophysiology of spatial scene analysis: the mismatch negativity (MMN) is sensitive to the ventriloquism illusion.

OBJECTIVES: The ventriloquism effect is the tendency to underestimate the spatial separation between synchronous auditory and visual signals moderately separated in space. If, as it is thought, this effect is pre-attentive, it could modulate the mismatch negativity (MMN) that indexes the automatic, pre-attentive detection of deviant auditory stimuli rarely occurring in a sequence of standard stimuli. We assessed the existence of an MMN evoked by auditory and visual signals made up of standard sounds coming from the same location as the visual signal and deviant sounds coming from lateral deviations (20 or 60 degrees). As first observed in a behavioral study, a ventriloquism effect occurred for 20 degrees spatial separation but not for 60 degrees. METHODS: Cortical evoked potentials were recorded using the oddball paradigm on 8 adults in auditory alone and audiovisual conditions. RESULTS: In the auditory alone condition, each spatial localization contrast elicited a significant MMN. In the audiovisual condition, a significant MMN was only evoked for the 60 degrees contrasts. CONCLUSIONS: The MMN evoked by spatial separation contrasts (20 and 60 degrees) in the auditory alone condition was suppressed by the corresponding audiovisual condition only when the latter yielded a ventriloquism effect, suggesting that this effect occurs at an early perceptual level.

Acoustic Stimulation↗
PubMed2002

Percutaneous stereotactic en bloc excision of nonpalpable breast carcinoma: a step in the direction of supraconservative surgery.

Recently, the advanced breast biopsy instrumentation (ABBI) system has been introduced as an alternative to conventional breast biopsy techniques. This study was prospectively conducted to evaluate the potential of the ABBI method in locoregional management of a consecutive series of patients with nonpalpable mammographically detected breast carcinomas. Sixty-one consecutive patients underwent an ABBI procedure as a first step before possible surgery for nonpalpable breast lesions that would in any case require complete excision. For the 27 patients in whom the ABBI biopsy revealed malignancy further surgery was recommended, including re-excision of the biopsy site and axillary dissection in cases of infiltrating carcinoma. We calculated the probabilities that the ABBI specimen would have tumor-free margins and that a definitely complete excision had been achieved as a function of the mammographic or pathological diameter of the cancer. For cancer with a pathological diameter less than 10 mm measured on the ABBI specimen, the probability (92%) of obtaining complete resection was significantly better than for larger lesions (P=0.01, Fisher's exact test). Although the therapeutic perspectives for the ABBI method are limited at present, we suggest that this approach is a first step in the direction of a surgical strategy that is better adapted to the pathological characteristics peculiar to these small tumors, whose incidence is increasing.

Journal Article↗
PubMed2002

[Patterns physicians use to screen for gestational diabetes: descriptive analysis in a cohort of 701 women].

OBJECTIVE: To study the way physicians screen for gestational diabetes. PATIENTS AND METHODS: Descriptive analysis of the pattern of screening used by physicians for 701 women who gave birth in a public or private maternity in the Rhône district in France. RESULTS: Overall, a screening test was used in 17.7% of the women (95%CI 14.9-20.7). A 50 g glucose tolerance test was performed in 60% of the screening prescriptions and was positive in 37.3%. One-third of the screening tests were achieved after the 28th gestational week. About half of the women were at risk for gestational diabetes. Among them, 24.6% had had a screening test. Factors associated with prescription of a screening test were gestational diabetes or macrosomia in a previous pregnancy, diabetes in relatives, high body mass index, weight gain of more than 15 kg, African origin, and follow-up in a public maternity. The diagnosis of gestational diabetes was made in 9 women. The prevalence of gestational diabetes was 1.28% (95%CI 0.59%-2.42%). CONCLUSION: Guidelines from the national colleges of obstetricians and endocrinologists for systematic screening for gestational diabetes are not properly applied. Questions concerning the implementation, results, and feasibility of these guidelines are raised.

Adult↗
PubMed2002

Two-phase study to assess the number of cases based on claims databases: characteristics of the validation data set.

OBJECTIVE: In a two-phase study design, the characteristics of an external data set were studied for precision and bias of the number of incident or prevalent cases of a disease obtained from claims databases. METHODS: In the study population (first phase), incident or prevalent cases were counted whereas external data (second phase) provided sensitivity and specificity estimates to count cases in a claims database. Influence of potential differences in sensitivity and specificity between the two phases were evaluated. This was illustrated for 50-90% sensitivity and 99-99.99% specificity ranges. RESULTS AND CONCLUSIONS: The impact of differences in sensitivity and specificity depends on the odds of disease in the study population. We provide advice on the choice of adequate data sets to correct claims database estimates.

Bias↗
PubMed2001

Regulation of microglial development: a novel role for thyroid hormone.

The postnatal development of rat microglia is marked by an important increase in the number of microglial cells and the growth of their ramified processes. We studied the role of thyroid hormone in microglial development. The distribution and morphology of microglial cells stained with isolectin B4 or monoclonal antibody ED1 were analyzed in cortical and subcortical forebrain regions of developing rats rendered hypothyroid by prenatal and postnatal treatment with methyl-thiouracil. Microglial processes were markedly less abundant in hypothyroid pups than in age-matched normal animals, from postnatal day 4 up to the end of the third postnatal week of life. A delay in process extension and a decrease in the density of microglial cell bodies, as shown by cell counts in the developing cingulate cortex of normal and hypothyroid animals, were responsible for these differences. Conversely, neonatal rat hyperthyroidism, induced by daily injections of 3,5,3'-triiodothyronine (T3), accelerated the extension of microglial processes and increased the density of cortical microglial cell bodies above physiological levels during the first postnatal week of life. Reverse transcription-PCR and immunological analyses indicated that cultured cortical ameboid microglial cells expressed the alpha1 and beta1 isoforms of nuclear thyroid hormone receptors. Consistent with the trophic and morphogenetic effects of thyroid hormone observed in situ, T3 favored the survival of cultured purified microglial cells and the growth of their processes. These results demonstrate that thyroid hormone promotes the growth and morphological differentiation of microglia during development.

Animals↗
PubMed2001

Behavioral and electrophysiological study of phonological priming between bisyllabic spoken words.

Phonological priming between bisyllabic (CV.CVC) spoken items was examined using both behavioral (reaction times, RTs) and electrophysiological (event-related potentials, ERPs) measures. Word and pseudoword targets were preceded by pseudoword primes. Different types of final phonological overlap between prime and target were compared. Critical pairs shared the last syllable, the rime or the coda, while unrelated pairs were used as controls. Participants performed a target shadowing task in Experiment 1 and a delayed lexical decision task in Experiment 2. RTs were measured in the first experiment and ERPs were recorded in the second experiment. The RT experiment was carried out under two presentation conditions. In Condition 1 both primes and targets were presented auditorily, while in Condition 2 the primes were presented visually and the targets auditorily. Priming effects were found in the unimodal condition only. RTs were fastest for syllable overlap, intermediate for rime overlap, and slowest for coda overlap and controls that did not differ from one another. ERPs were recorded under unimodal auditory presentation. ERP results showed that the amplitude of the auditory N400 component was smallest for syllable overlap, intermediate for rime overlap, and largest for coda overlap and controls that did not differ from one another. In both experiments, the priming effects were larger for word than for pseudoword targets. These results are best explained by the combined influences of nonlexical and lexical processes, and a comparison of the reported effects with those found in monosyllables suggests the involvement of rime and syllable representations.

Acoustic Stimulation↗
PubMed2001

Human islet transplantation network for the treatment of Type I diabetes: first data from the Swiss-French GRAGIL consortium (1999-2000). Groupe de Recherche Rhin Rhĵne Alpes Genève pour la transplantation d'Ilots de Langerhans.

AIMS/HYPOTHESIS: Improvements in islet transplantation require clinical series large enough to implement controlled new strategies. The goal of this study was to demonstrate the feasibility of a multicentre network for islet transplantation in Type I (insulin-dependent) diabetic patients. METHODS: The five centres (Besançon, Geneva, Grenoble, Lyon, Strasbourg) of the GRAGIL network allow pancreas procurement, recipient recruitment, transplantation procedure and follow-up. Islet isolation is, however, performed in one single laboratory (Geneva). Pancreata were procured in each of the five centres and transported to Geneva with an ischaemia time of less than 8 hours. Islets were isolated using a standard automated method. If the islet number was too low for a graft (< 6,000 Islet-equivalent/kg), islets were cultured up to 12 days until another isolation was possible. Islets were transplanted by percutaneous transhepatic intraportal injection. Immunosuppression consisted of cyclosporine, mycophenolate mofetil, steroids and an anti-interleukin 2 receptor antibody. RESULTS: From March 1999 to June 2000, 56 pancreata procurements were performed with an average yield of 234500 islet-equivalent, with 32 preparations over 200000 islet-equivalent. Ten C-peptide negative Type I diabetic patients (5 men and 5 women, median age 44 years, median diabetes duration 29 years) with an established kidney graft (> 6 months) received 9,030 +/- 1,090 islet-equivalent/kg with a median purity of 63 %. The number of pancreata required for each graft was 1 (n = 5) or 2 (n = 5). At the completion of a 12 month follow-up, we observed 0% primary nonfunction, 50% graft survival and 20% insulin-independence. CONCLUSIONS/INTERPRETATION: This study demonstrates the interest and the feasibility of a multicentre collaboration in human islet transplantation.

Adult↗
PubMed2001

En bloc excision of nonpalpable breast lesions using the advanced breast biopsy instrumentation system: an alternative to needle guided surgery?

This study was prospectively conducted to evaluate the clinical potential of the advanced breast biopsy instrumentation (ABBI) system as an alternative to needle localization and open surgery in the management of nonpalpable breast lesions (NPBL). One hundred and eighty-six consecutive patients were referred for management of NPBL. Thirty-six underwent an ABBI procedure, offered as a first step before possible surgery for lesions which would in any case have required complete excision. The 18 patients with a malignant ABBI biopsy underwent re-excision of the biopsy site and axillary dissection was carried out in cases of infiltrating carcinoma. The other 150 patients underwent image-guided needle biopsy. Following these procedures, 60/150 (40%) patients underwent needle-guided surgery. Finally, 96/186 (51%) patients required complete excision. A total of 43 benign lesions and 53 carcinomas were confirmed. Thirty-six out of 96 (38%) excisions were obtained with the ABBI system; 17/43 (40%) benign lesions and 11/53 (21%) carcinomas were completely removed with the ABBI system. Out of 9 malignant specimens with a pathological size less than 10 mm, 5/9 (55%) had tumor-free margins and in 8/9 (89%) no residual disease was found at re-excision. The preliminary results of this study suggest that, in selected cases, en bloc excision using the ABBI procedure could be an alternative to conventional surgery.

Adult↗
PubMed2001

Indicators of myocardial dysfunction and quality of life, one year after acute infarction.

BACKGROUND: There remains controversy concerning the association between myocardial dysfunction diagnosed soon after acute myocardial infarction (AMI), and subsequent quality of life. AIMS: We searched for a correlation between criteria of myocardial dysfunction assessed within the first month after AMI, and quality of life perceived 1 year later. METHODS: Six hundred and seventy-one patients were followed up and quality of life was assessed using the Nottingham Health Profile. Spearman correlation was used for univariate analyses. A logistic regression identified independent predictors of impaired quality of life. RESULTS: Patients perceiving inferior quality of life were 61% for energy, 61% for sleep, 49% for physical mobility, 49% for pain, 63% for emotional reactions, and 28% for social isolation. Impaired quality of life was not associated with the initial Killip class. A low ejection fraction was associated with impaired physical mobility (OR=1.21, 95% CI=1.05-1.39). Presence of abnormally contracting myocardial segments was associated with impaired mobility (1.40, 1.09-1.80) and with increased pain (1.30, 1.02-1.66). The presence of diseased coronary vessels was associated with pain (1.25, 1.06-1.46). CONCLUSION: Myocardial dysfunction was generally associated with impaired quality of life. This has to be considered when assessing improvement of quality of life after medical or surgical treatment of AMI.

Activities of Daily Living↗
PubMed2001

Sensitivity and specificity of third-generation hepatitis C virus antibody detection assays: an analysis of the literature.

This study assessed the sensitivity and specificity of third-generation serological hepatitis C diagnostic tests from an analysis of the literature. The literature analysis was run using criteria from McMaster University for the assessment of diagnostic tests. The selected studies were grouped according to the type of population at high and low risk for hepatitis C virus (HCV) infection and to the type of reference test. The homogeneity of the sensitivity and the specificity was tested in each group using a Fisher's exact test. Of 132 studies, 10 were selected. When the estimates were homogeneous, summary point estimates and confidence intervals were computed; when the estimates were heterogeneous, subgroup analysis was performed. The sensitivity of third-generation enzyme-linked immunosorbent assay (ELISA3) was estimated at 98.9% (95% CI: 94-100%) in patients with chronic liver disease and at 97.2% (95% CI: 92-99%) in panels of sera. ELISA3 specificity was found at 100% in patients with chronic liver disease. The sensitivity of the third generation recombinant immunoblot assay (RIBA3) was assessed at 78.8% (95% CI: 65-89%) in haemodialysed patients. This analysis provides evidence for the good sensitivity and specificity of ELISA3 assays particularly in high risk patient groups and confirms their use for screening in these populations. Further studies are needed to assess properly RIBA3 in general population and in risk patients.

Enzyme-Linked Immunosorbent Assay↗
PubMed2001

Cost-effectiveness analysis of strategies for hepatitis C screening in French blood recipients.

BACKGROUND: In a context of scarce health resources and varied medical practices, the aim of this study was to compare cost-effectiveness of different screening strategies for hepatitis C virus among blood recipients. METHODS: A cost-effectiveness model was used to test nine screening strategies in three survival categories. Three Markov models were used for three methods of follow-up. The marginal cost-effectiveness ratio was estimated to compare the screening strategies. RESULTS: Hepatitis C virus serology by enzyme-linked immunosorbent assay and confirmation by detection of the virus RNA was proved to be the dominant strategy. The marginal cost-effectiveness ratios were for subjects under 40 and low-volume transfusion patients, 776,474 and 2,636,500 French Francs-1996 (about USD 111,000 and 376,650) per life-year gained, respectively. Sensitivity analysis showed that the marginal cost-effectiveness ratio was influenced by the prevalence and the survival rates. The lower marginal cost-effectiveness ratio was estimated at 690,221 French Francs-1996 per life-year gained. CONCLUSION: This study showed high costs and few life-years gained for the dominant strategy even for the more favourable risk group. New studies may be carried out for new screening and therapeutic strategies.

Adult↗
PubMed2001

[Cost-benefit ratio of tick-borne encephalitis vaccination of French troops based in Kosovo].

BACKGROUND: French military troops based in Kosovo are exposed to Tick-Borne Encephalitis (TBE) biorisk. An efficacious vaccine is available to prevent this disease, burdened by high morbidity and mortality. The epidemiologic features of TBE in Kosovo are unprecise. To help the French Department of Defense to make a decision about immunization against TBE, we performed a cost-benefit analysis. METHODS: By a Bayes'analysis decision, we have estimated the net benefits for a three-injection vaccine program versus absence of vaccination, for all French military troops based in Kosovo. Time expectancy was 4 years. Through the review of several medical reports, we have estimated the useful parameters for this study: morbidity incidence rate, mortality rate, sequelae rate, efficacy vaccine and side effects. We have chosen as initial hypothesis a sero-conversion rate of 1,080 per 100,000 men-by-year. Human life was valorized in francs, by calculating the allowance paid by Department of Defense to the family in case of death or for sequelae. RESULTS: Net benefits arised to 2.17 millions of francs. The vaccine program cost was 25.0 millions of francs. 140 cases of encephalitis viruses were saved by vaccination. Nevertheless a sensibility analysis has shown that results are well reliable with TBE incidence rate. CONCLUSION: The break even point being close to the incidence rate of the initial assumption, the decision to vaccine all French military troops depends at the same time on a better knowledge of the incidence of the disease in Kosovo, but also of the number of potentially avoided cases of tick-borne encephalitis and of the programs of vaccination concerning this disease of the other countries forming the United Nations Organization forces.

Bayes Theorem↗