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Biomedical subjects

B Tavernier

Publications and source records attributed to B Tavernier.

At least 19 recordsLinked to original sources
PubMed2006

Cross-sectional association between homocysteine and motor function in the elderly.

OBJECTIVE: To determine if there is a cross-sectional association between homocysteine (tHcy) level and measures of gait and balance in elderly subjects. METHODS: We studied 3,609 noninstitutionalized subjects aged 65 to 85 years from the Dijon (France) center of the Three-City Study. tHcy concentration was measured from fasting blood samples. Motor function was assessed by measuring walking speed and by using a modified version of the Tinetti scale. RESULTS: After adjustment for confounders, mean maximum walking speed (MWS) decreased with increasing tHcy levels (p = 0.001). The odds ratio (OR) (95% CI) for having a MWS below the 40th percentile was 1.9 (1.4 to 2.5) in subjects with tHcy levels in the upper quintile compared with those in the lowest quintile. Compared with subjects in the lowest tHcy quintile, the OR for having a modified Tinetti score below 16 ranged from 1.0 (0.8 to 1.4) in the second quintile to 1.9 (1.3 to 2.6) in the upper quintile (p < 0.0001). CONCLUSIONS: Elevated homocysteine concentrations are associated with worse motor performances in the elderly. These findings support the hypothesis of a vascular contribution to motor function.

Age Factors↗
PubMed2006

Non-invasive prediction of fluid responsiveness during major hepatic surgery.

BACKGROUND: The aim of this study was to evaluate potential predictors of fluid responsiveness obtained during major hepatic surgery. The predictors studied were invasive monitoring of intravascular pressures (radial and pulmonary artery catheter), including direct measurement of respiratory variation in arterial pulse pressure (PPVart), transoesophageal echocardiography (TOE), and non-invasive estimates of PPVart from the infrared photoplethysmography waveform from the Finapres (PPVfina) and the pulse oximetry waveform (PPVsat). METHODS: We conducted a prospective study of 54 fluid challenges (250 ml colloid) given for haemodynamic instability in eight patients undergoing hepatic resection. Fluid responsiveness was defined as an increase in stroke volume index (SVI) >or=10%. The following variables were recorded before each fluid challenge: right atrial pressure (RAP), pulmonary artery occlusion pressure (PAOP), PPVart, PPVfina, PPVsat, and the TOE-derived variables left ventricular end-diastolic area index (LVEDAI), early/late (E/A) diastolic filling wave ratio, deceleration time of the E wave (MDT) of mitral flow and the systolic fraction of the pulmonary venous flow (SF). RESULTS: Only PPVfina, PPVart (both P<0.001), PPVsat (P=0.02), LVEDAI and MDT (both P=0.04) were different in responder vs non-responder fluid challenges. The areas under the receiver operating characteristic (ROC) curves were 0.81 (PPVfina), 0.79 (PPVart), 0.70 (LVEDAI), 0.68 (PPVsat and MDT), 0.63 (RAP), 0.62 (E/A), 0.55 (PAOP) and 0.42 (SF). The areas under the ROC curves for RAP, E/A, PAOP and SF were significantly less than that for PPVfina (P<0.05 in each case). Only PPVart (r=0.59, P=0.0001) and PPVfina (r=0.56, P=0.0001) correlated with the fluid challenge-induced changes in SVI. CONCLUSIONS: PPVart and PPVfina predict fluid responsiveness during major hepatic surgery. This suggests that intraoperative monitoring of fluid responsiveness may be implemented simply and non-invasively.

Aged↗
PubMed2005

Correlates of regular fish consumption in French elderly community dwellers: data from the Three-City study.

OBJECTIVE: Several studies have found an inverse association between fish consumption and risk of dementia. The objective of this study was to describe the characteristics of older fish consumers, in order to identify potential confounders in this relationship. DESIGN: Cross-sectional analysis of the baseline data of a prospective cohort study. SETTING: Bordeaux, Dijon, and Montpellier (France) in 1999-2000. SUBJECTS: A total of 9280 community dwellers aged 65 y and above participating in the baseline examination of the Three-City Study. INTERVENTIONS: All participants answered a face-to-face interview and underwent a physical examination. Cross-sectional analyses were performed by logistic regressions. RESULTS: Regular fish consumers (at least weekly) had a higher education (OR from 1.19 to 1.65, P = 0.0003) and income (OR from 1.37 to 1.89, P < 0.0001). Controlling for age, sex, education, and city, they had a higher consumption of pulses, fruit, and vegetables (P < 0.001). They were more often alcohol drinkers (P < 0.0001). They felt in better health (P < 0.05), exhibited less depressive symptoms (P < 0.001), and scored higher on the Mini Mental Status Examination (P < 0.05). However, their objective physical health status was not better, except that they were leaner. They suffered more often from hypertension and past stroke. CONCLUSIONS: Socioeconomic status, dietary habits, depression, and vascular risk factors could act as confounders in the relationship between fish consumption and risk of dementia.

Aged↗
PubMed2005

The effect of calcium channel blockers on outcome following the surgical treatment of phaeochromocytomas and paragangliomas.

The peri-operative management of patients undergoing surgery for phaeochromocytoma or paraganglioma with calcium channel blockers (CCB) and their impact on postoperative morbidity and mortality were studied. The medical records of 105 patients undergoing surgery between 1991 and 2002 were analysed retrospectively. In all patients, the calcium channel blocker nicardipine was used for the peri-operative management of haemodynamic changes. Sixty-five patients (61.9%) showed transient intra-operative hypertension. Systolic blood pressure (SBP) > 220 mmHg and SBP > 180 mmHg for > 10 consecutive minutes was observed in 14 (13%) and four patients (2.8%), respectively. SBP < 80 mmHg for > 10 consecutive minutes occurred in 13 patients (12.3%). Eleven patients (10.4%) developed postoperative complications and three patients died (2.8%). The median (range) ICU and hospital length of stay were, respectively, 1 (0-7) day and 10 (2-35) days. The sole use of calcium channel blockers for the peri-operative management of phaeochromocytoma and paraganglioma resection does not prevent all haemodynamic changes; however, its use was associated with a low morbidity and mortality.

Adolescent↗
PubMed2004

Sociodemographic differences in dietary habits in a population-based sample of elderly subjects: the 3C study.

PURPOSE: Diet plays an important role in maintaining quality of life in ageing and can be influenced by sociodemographic factors. We aimed to describe dietary habits in a large population-based sample of elderly people and to explore how they may vary according to sex, age, educational level and lifestyle. METHODS: 9250 community dwellers aged 65 years and over recruited in three French cities were interviewed about their food habits with a brief frequency questionnaire. For each food considered, the subjects were classified as occasional or regular consumers. Quantities of alcoholic beverages consumed daily were also assessed. Dietary habits were compared for men and women separately according each sociodemographic factor. RESULTS: Women were characterized by a more regular consumption of fruit and vegetables and drunk fewer alcoholic beverages. Older subjects ate meat, fish, cereals, raw vegetables and pulses less regularly. The proportion of regular consumers of fish, raw fruit, raw vegetables and cooked fruit or vegetables and the quantity of alcohol consumed increased with educational level. Subjects living alone were less regular consumers of almost all foods. DISCUSSION: The results show that even in a sub-population of elderly people, dietary patterns can vary greatly according to several factors. Identifying such factors is of value for future analytic studies on nutrition and health in the elderly. In view of dietary recommendations advising a high consumption of fruit and vegetables, subjects living alone and people with a low educational level are particularly at risk and should be encouraged to eat more balanced meals.

Aged↗
PubMed2001

[Xenon anesthesia: from myth to reality].

OBJECTIVE: To analyze the current knowledge concerning xenon anaesthesia. DATA SOURCES: References were obtained from computerized bibliographic research (Medline), recent review articles, the library of the service and personal files. STUDY SELECTION: All categories of articles on this topic have been selected. DATA EXTRACTION: Articles have been analysed for history, biophysics, pharmacology, toxicity and environmental effects and using prospect. DATA SYNTHESIS: The noble gas xenon has anaesthetic properties that have been recognized 50 years ago. Xenon is receiving renewed interest because it has many characteristics of an ideal anaesthetic. In addition to its lack of effects on cardiovascular system, xenon has a low solubility enabling faster induction of and emergence from anaesthesia than with other inhalational agents. Nevertheless, at present, the cost and arety of xenon limit its widespread use in clinical practice. The developement of closed rebreathing system that allowed recycling of xenon and therefore reducing its waste has led to a recent interest in this gas. Reducing its cost will help xenon to find its place among anaesthetic agents. An European multicentric clinical trial under submission will contribute to the discussion of the opportunity for xenon introduction in anaesthesia.

Anesthesia, Inhalation↗
PubMed2001

[Hemodynamic instability and paraplegia after thoracotomy for excision of a cardiac pheochromocytoma].

We report the occurrence of a sustained hypotension (vasoplegia) following thoracic phaeochromocytoma surgery. Diagnosis of spinal cord injury was done by magnetic nuclear resonance (MNR) showing surgical "Horsley wax" inside the vertebral canal and ischaemic signal inside the anterior part of the spine cord. Removal of "Horsley wax" dramatically improved arterial blood pressure but did not correct all neurologic disorders. Haemodynamic disorders related to spinal cord injury are rare after thoracotomy, and may have been enhanced by the haemodynamic instability typically associated with phaeochromocytoma surgery. Early diagnosis has to be done by MNR.

Heart Neoplasms↗
PubMed2001

Perioperative care of diabetic patients.

Diabetes mellitus is the most common metabolic disease and its incidence is increasing. New classifications have been recently proposed based upon a better knowledge of pathogenesis, mechanisms of glucose transport and insulin resistance. The perioperative care of diabetic patients is less dependent on blood-glucose control, which needs to be exceptionally tight, and is usually easily obtained thanks to pharmacological improvements, human insulins and analogues, technical progress with blood-glucose monitoring at the bedside and infusion with constant flow rates. More important is the influence of end-organ pathology, often clinically silent, which must be carefully assessed during the preoperative evaluation. The organ impairments concern especially the heart, but also all those organs that were modified by abnormal glycosylated proteins. The pre-existing pathology has many consequences on anaesthesia management; the anaesthetic technique depends essentially on their existence. A better long-term control of diabetes both for Type 1 and Type 2 by insulins, and the new oral anti-diabetic drugs reduce the incidence of the end-organ pathology and the risk linked to organ failures in the perioperative period.

Blood Glucose↗
PubMed2001

Influence of structure on nickel-titanium endodontic instruments failure.

The purpose of this work was to investigate the process history on fracture life of nickel-titanium endodontics files. The results are based on microstructural investigations of nickel-titanium engine-driven rotary instruments based on X-ray diffraction, scanning electron microscopy, and microhardness tests. Endodontic files are very work-hardened, and there is a high density of defects in the alloy that can disturb the phase transformation. The microhardness Vickers confirmed these observations (dislocations and precipitates). The X-rays show that experimental spectrum lines are extended, typical of a distorted lattice. The surface state of the endodontic files (scanning electron microscopy) is an important factor in failure and fracture initiation.

Dental Alloys↗
PubMed2001

Phosphorylation-dependent alteration in myofilament ca2+ sensitivity but normal mitochondrial function in septic heart.

The subcellular mechanisms responsible for myocardial depression during sepsis remain unclear. Recent data suggest a role for impaired energy generation and utilization, resulting in altered contractile function. Here, we studied the energetic and mechanical properties of skinned fibers isolated from rabbit ventricle in a nonlethal but hypotensive model of endotoxemia. Thirty-six hours after lipopolysaccharide (LPS) injection (in the presence of altered myocardial contractility), mitochondrial respiration, coupling between oxidation and phosphorylation, and creatine kinase function were similar in preparations from endotoxemic (LPS) and control animals. The maximal Ca2+-activated force was similar in LPS and control preparations. However, the Ca2+ concentration corresponding to half-maximal force (pCa50, where pCa = -log10[Ca2+]) was 5.55 +/- 0.01 (n = 11) in LPS fibers versus 5.61 +/- 0.01 (n = 10) in control fibers (p < 0.01). Both protein kinase A (PKA) and alkaline phosphatase treatment led to the disappearance in the difference between control and LPS pCa50 values. Incubation of control fibers with the nitric oxide donor S-nitroso-N-acetylpenicillamine (SNAP) did not change the Ca2+ sensitivity after subsequent skinning, whereas isoproterenol decreased pCa50 from 5.62 +/- 0.01 to 5.55 +/- 0.01 (p < 0.01). These data suggest that during sepsis, cardiac mitochondrial and creatine kinase systems remain unaltered, whereas protein phosphorylation decreases myofibrillar Ca2+ sensitivity and may contribute to the depression of cardiac contractility.

Actin Cytoskeleton↗
PubMed2001

Effect of dentin adhesives on the enamel-dentin/composite interfacial microleakage.

PURPOSE: To evaluate the microleakage at the enamel-dentin resin-based composite (RBC) interface of 4 dentin bonding systems (DBS). MATERIALS AND METHODS: Standardized kidney-shaped Class V cavities were prepared on the buccal and lingual surfaces at the cemento-enamel junction of 90 extracted human teeth and restored with a microhybrid RBC (Filtek P60) following application of either Excite (EXC), a single component adhesive; Prompt L Pop (PLP), a self-etching priming bonding adhesive; Clearfil SE Bond (SEB), a self-etching adhesive; or OptiBond Solo (OPS), a single component adhesive. The teeth were thermocycled, immersed in a dye solution and sectioned. The enamel failures and the occlusal and cervical dentin microleakages were measured. RESULTS: Significant differences were evident between the self-etching adhesives and the adhesives using phosphoric acid (P 0.05) for the enamel. The occlusal dentin microleakage was similar for the four DBS. PLP presented the worst values at the cervical dentin margin compared to the three other DBS. Significant differences were noted between PLP and EXC and OPS, which performed better.

Acid Etching, Dental↗
PubMed2000

Cardiac contractile impairment associated with increased phosphorylation of troponin I in endotoxemic rats.

The subcellular mechanisms underlying intrinsic myocardial depression during sepsis remain poorly defined, in particular the relative roles of altered intracellular Ca2+ transients versus changes in myofilament properties. We studied contractile function of cardiac myocytes isolated 12 h after induction of endotoxemia (5 mg/kg intravenous E. coli lipopolysaccharide [LPS]) in conscious rats. Cardiomyocytes from LPS-injected rats had depressed twitch shortening compared with control cells (4.10.2% versus 7.80.3%; P2+ transients (peak indo-1 ratio 1.130.02 versus 1.120.02; P = NS). Contractile depression was unaffected by inhibitors of nitric oxide synthase. Steady-state myofilament response to Ca2+, assessed by tetanization of intact cells over a range of [Ca2+], was reduced significantly in the LPS group (P2+ was unaffected by isoproterenol (3 nmol/L) in endotoxemic cells, whereas there was a rightward shift in control cells. A reduction in myofilament response to Ca2+ is the major determinant of intrinsic cardiac depression in systemic endotoxemia. This condition appears to be related to an increase in myocardial troponin I phosphorylation.

Actin Cytoskeleton↗
PubMed2000

Shortening velocity of skeletal muscle from humans with malignant hyperthermia susceptibility: effects of halothane.

The aim of this investigation was to assess the effect of halothane on the velocity of shortening and lengthening of muscle from normal subjects and from patients with malignant hyperthermia susceptibility. Strips were mounted horizontally at optimal length in normal Krebs-Ringer's solution and mechanical parameters were obtained before and after exposure to 3 vol.% halothane. The maximun shortening velocity at zero load (V(max)) was determined by using Hill's characteristic equation. The contraction and relaxation indices were measured under isotonic and isometric conditions: maximum shortening and lengthening velocities (maxV(c) and maxV(r), respectively); isometric peak twitch tension; peak of the positive (+dP/dt(max)) and negative (-dP/dt(max)) twitch tension derivative; ratio R1=maxV(c)/maxV(r) and ratio R2=(+dP/dt(max))/(-dP/dt(max)). In normal muscle, halothane markedly increased V(max), maxV(c) and peak twitch tension by 30+/-10%, 30+/-5% and 40+/-15%, respectively. The maxV(r) values increased concomitantly with the maxV(c) values, such that no change in the ratio R1 was observed. Both +dP/dt(max) and -dP/dt(max) increased such that the ratio R2 did not vary. In malignant hyperthermia susceptibility muscle, halothane induced a significant decrease in V(max) (-30+/-10%) and maxV(r) (-45+/-15%) without changing maxV(c). The decrease in maxV(r) was greater than that of maxV(c), such that the ratio R1 increased significantly. Peak twitch tension and +dP/dt(max) remained unchanged whereas -dP/dt(max) decreased significantly; the ratio R2 increased by 40+/-10%. These results suggest that halothane alters the contractile properties of malignant hyperthermia susceptibility muscle.

Anesthetics, Inhalation↗
PubMed2000

[Postoperative mortality a university Department of General Surgery: incidence of cardiac-related deaths].

OBJECTIVES: To evaluate the incidence of cardiac deaths following noncardiac nonvascular surgery. STUDY DESIGN: Retrospective survey. PATIENTS: All patients undergoing mainly endocrinous and digestive surgery in a University department of general surgery between 1991 and 1996. METHODS: Analysis of all deaths occurring intra- and postoperatively, until discharge of the patients. Demographic and medical data, including patent myocardial ischaemia and risk factors for coronary artery disease, were recorded and compared with a control group including all patients undergoing surgery from January to September 1996. RESULTS: In the 8,700 patients who underwent mainly endocrine neck surgery (66%), or intra-abdominal surgery (31%), the mortality rate (n = 96) was 1.1% (95% confidence interval [95% CI] = 0.9-1.3%). Patent myocardial ischaemia or high risk factors for coronary artery disease were existing in 24% of patients with neck surgery, 31% of those with intra-abdominal surgery, and in 60% of the deceased patients (P < 0.01 vs control group). Those who died were older, were in a higher ASA physical class, and had undergone an emergency procedure more often than patients of the control group (P < 0.002 for each parameter). Two cardiac deaths, in patients with a patent cardiopathy, were recorded (cardiac mortality: 0.02%; 95% CI = 0.003-0.08%). The main cause of death was infection (n = 46), followed by haemorrhage (n = 12). Seven deaths remained unexplained. CONCLUSION: This study suggests that cardiac morbidity is a rare cause of death after noncardiac nonvascular surgery.

Adult↗
PubMed2000

Assessment of tissue oxygenation in the critically-ill.

It is hypothesized that tissue dysoxia and O2 debt are major factors in the development and the propagation of multiple organ failure in critically ill patients. Dysoxia is the result of an abnormal relationship between O2 supply (DO2) and O2 demand and translates into increased anaerobic metabolism and tissue and blood lactate concentration. First-line therapeutic strategies used to avoid the development of an O2 debt involve correction of cardiac output, haemoglobin, and O2 saturation in order to increase DO2 above its critical value. They are not sufficient, however, to ensure appropriate end-organ perfusion and oxygenation. The adequacy of cardiac output towards tissue metabolic requirements may be appreciated by venous-to-arterial and gut mucosal-to-arterial PCO2 differences. This review details these strategies and discusses their usefulness in current practice.

Critical Illness↗
PubMed1999

[Caffeine skinned fiber tension test: application to the diagnosis of susceptibility to malignant hyperthermia].

OBJECTIVE: To assess the reactivity of sarcoplasmic reticulum to caffeine, using the skinned muscle fibre tension test and to compare it with the reference in vitro contracture test in the diagnosis of malignant hyperthermia (HM) susceptibility. STUDY DESIGN: Laboratory investigation. MATERIAL: Muscle biopsies from 63 patients, including 29 classified as susceptible to MH (MHS) and 34 classified as non-susceptible (MHN) according to criteria of the European and the North American MH groups. METHOD: The reactivity to caffeine and halothane of skinned muscle fibres was compared, according to the type of fibres, with the data of the in vitro contracture test. The type of fibres (type I: oxidative, slow; type II: glycolytic, fast) were determined with strontium dose-response curves. RESULTS: The reactivity to caffeine was significantly lower in the MHS group, for both type I and type II skinned fibres. However, in comparison with the data of the in vitro contracture tests, using the ROC curve analysis, the best sensitivity-specificity compromise was 90%-71% and 74%-84% for type I and type II skinned fibres respectively. CONCLUSION: The skinned muscle fibre tension test cannot be used instead of the in vitro contracture test for the diagnostic of MHS. However, it may strengthen the data of the latter.

Caffeine↗