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G Janvier

Publications and source records attributed to G Janvier.

At least 19 recordsLinked to original sources
PubMed2002

Infected mediastinitis secondary to perforation of superior vena cava by a central venous catheter.

We describe the first case of infected mediastinitis associated with central venous catheter insertion. The rare occurrence of this complication may be explained by the fact that it results from central venous catheter-related bloodstream infection and catheter perforation of superior vena cava. The symptoms of this complication (chest pain, dyspnoea) are not specific. Diagnosis should be confirmed by chest x-ray and computerized tomography which show hydromediastinum and pleural effusion. Removal and subsequent culture of the catheter tip will confirm infection. Appropriate antibiotic therapy, guided by sensitivities of the cultured organisms, should be commenced. Any pleural effusion should be drained by thoracocentesis, and the pleural fluid cultured. In case of fever, bacteraemia or shock, a thoracotomy to drain mediastinal and pleural effusions may be considered.

Catheterization, Central Venous↗
PubMed2002

Platelet function point-of-care tests in post-bypass cardiac surgery: are they relevant?

BACKGROUND: Platelet dysfunction is an important cause of excessive bleeding after cardiac surgery. We assessed two platelet function point-of-care tests: the platelet function analyser (PFA-100) and the Hemostatus(TM) in patients with and without excessive bleeding after cardiac surgery with cardiopulmonary bypass. METHODS: Mediastinal chest tube drainage (MCTD) was measured for the first 6 h in the intensive care unit (ICU). Haematology and coagulation tests were done on arrival in the ICU, and when excessive bleeding occurred (MCTD >1 ml kg(-1) h(-1)) or after 3 h. RESULTS: Eighteen patients bled excessively and 27 had normal MCTD. Hemostatus measurements were prolonged in those with excessive bleeding compared with the normal group. The times for PFA-100 adenosine diphosphate (ADP) and epinephrine were 91 vs 71 s (P=0.004) and 155 vs 114 s (P=0.02) in the bleeding and normal group s, respectively. None of the Hemostatus or PFA-100 values correlated with total MCTD. Depending on the agonist used, maximum aggregation was 33-81% and 52-86% in bleeding and normal groups, respectively. Only poor correlations were found between PFA-100 epinephrine and maximum aggregation in response to ADP (r=-0.52, P=0.03) or to collagen (r=-0.48, P=0.04). CONCLUSION: Patients bleeding excessively in the ICU had abnormal measurements in point-of-care tests without a dramatic decrease in aggregation. Except for patients with increased risk of postbypass bleeding, point-of-care tests are not useful for routine use after cardiac surgery.

Aged↗
PubMed2001

A long-term follow-up of an HIV type 1-infected patient reveals a coincidence of Nef-directed cytotoxic T lymphocyte effectors and high incidence of epitope-deleted variants.

Cytotoxic T lymphocytes (CTL) play a critical role in controlling human immunodeficiency virus-1 (HIV-1) and simian immunodeficiency virus (SIV) infections. However, in spite of developing a strong CTL response most HIV-1-infected patients eventually progress to AIDS. Amino acid changes in CTL epitope have been previously described and may permit HIV to escape from CTL immune responses. The importance of CTL selection pressure in controlling the course of viral evolution in HIV-infected patient remains debatable. For over a 10-year period, we longitudinally followed a patient for bulk unstimulated effector (eCTL) and stimulated memory CTL responses (mCTL) against the viral proteins Gag, Pol, and Nef. The patient showed a strong CTL response against Nef in unstimulated peripheral blood mononuclear cells with a peak during Month 40 of the follow-up. The mCTL response was also higher against Nef than Gag and Pol. PCR amplification and nucleotide sequencing of the plasma viral variants showed a viral variant with the epitope deletion that was detected early during the follow-up and essentially replaced the wild-type virus during the peak eCTL response. These studies support the importance of Nef epitope deletion as a mechanism for HIV-1 escape from CTL immune pressure.

Amino Acid Sequence↗
PubMed2001

[Reproducibility and interchangeability of the Thromboelastograph, Sonoclot and Hemochron activated coagulation time in cardiac surgery].

PURPOSE: Despite their common use in cardiac surgery, few studies have evaluated the reproducibility of the Thromboelastograph (TEG), of the Sonoclot (SCT), and of the activated coagulation time with celite (ACT-C) or kaolin (ACT-K) measured with the Hemochron, in clinical conditions of on-site monitoring of hemostasis. This study determined the reproducibility of those measurements, and evaluated the ability of various devices to substitute for the ACT-C. METHODS: Blood samples collected from 20 volunteers and 21 patients undergoing myocardial revascularization were analyzed in the two channels of the TEG, in two SCT and four Hemochron analyzers. The overall of TEG and SCT coagulation profiles were analyzed by a computerized TEG and an experienced observer respectively. The variation rate (V%) was calculated for each variable. The ability of ACT-K and SCT to substitute for ACT-C under different clinical conditions was evaluated. RESULTS: ACT-C and ACT-K V% ranged between 5.6% and 10.8% and between 6.7% and 12.4% respectively. TEG and SCT V% ranged between 3.1% and 9.5% and between 5.8% and 33.6% respectively, according to different conditions and parameters. In volunteers and non-heparinized patients, the ACT-C and ACT-K were interchangeable. No other test can substitute for the ACT-C when patients are heparinized during cardiopulmonary bypass (CPB). CONCLUSIONS: In the clinical conditions of use, on-site hemostasis monitoring devices providing the most reproducible measurements are, in decreasing order, the TEG, the Hemochron and the SCT. In heparinized patients and during CPB, results from different tests are not interchangeable, stressing the importance of establishing appropriate instrument-specific values for monitoring anticoagulation during cardiac surgery.

Adult↗
PubMed2001

Electronic ventilator temperature sensors as a potential source of respiratory tract colonization with Stenotrophomonas maltophilia.

Stenotrophomonas maltophilia (S. maltophilia) is an important cause of nosocomial infection among ventilated and immunocompromised patients, and among patients receiving broad-spectrum antimicrobials. We report a cluster of patients in a surgical intensive care unit who were colonized or infected with S. maltophilia. An epidemiological investigation was initiated after surveillance data revealed that eight patients were culture-positive from sputum for S. maltophilia in the preceding month. Review of respiratory care procedures revealed that when mechanical ventilators were serviced between patients, the electronic temperature probes used with servo-controlled humidifiers were wiped with inadequate disinfection. We collected cultures of case-patient room surfaces, sinks and ventilator equipment. S. maltophilia was recovered from room surfaces, ventilator expiratory circuits and a temperature sensor which had been kept in ambient air after disinfection. Patients and environmental isolates were examined by RAPD-PCR. Three clinical isolates and one environmental isolate had the same profile, which suggests cross-contamination or common source exposure. The outbreak was controlled by adequate disinfection of the temperature sensors. No single epidemic strain was identified but several observations support the conclusion that the temperature probes contributed to the outbreak.

Cross Infection↗
PubMed2000

Immune responses following simian/human immunodeficiency virus (SHIV) challenge of rhesus macaques after human immunodeficiency virus (HIV)-1 third variable domain (V3) loop-based genetic immunization.

Following DNA immunization of rhesus macaques with a plasmid encoding the human immunodeficiency virus (HIV)-1 third variable domain (V3) loop, presented by pseudo-viral envelope particles of hepatitis B virus, specific immune responses were induced. The primates were then inoculated with a chimeric simian/human immunodeficiency virus (SHIV). All the animals were infected, but the V3-specific immunization provided a relative attenuation of the acute phase of infection in the absence of neutralizing antibody. In all animals, SHIV-specific cytotoxic T-lymphocyte precursors (CTLp) were detected early in peripheral blood and lymph nodes. The viremia peak correlated significantly with the decrease in CD4+ T cells and with a transient increase in the percentage of natural killer cells. The infection induced an oligoclonalization of the CD8+ T-cell variable beta chain repertoire in the blood. Surprisingly, HIV envelope-specific CTLp generated by genetic immunization may be governed by distinct circulation rules compared to SHIV-specific CTLp induced by infection.

AIDS Vaccines↗
PubMed1999

Inhibition of platelet aggregation by abciximab but not by aspirin can be detected by a new point-of-care test, the hemostatus.

We have investigated the type of platelet defect that can be detected with the Hemostatus test performed with the Hepcon/HMS instrument (Medtronic) designed to investigate platelet function during and after surgery. This assay is based on the comparison of the activated clotting time of whole blood measured in cartridges containing kaolin or kaolin and platelet-activating factor in different concentrations. Addition of platelet-activating factor shortened the blood activated clotting time when the platelet counts were normal. However, when platelet counts were below 70000/microL, the activated clotting time was prolonged in all channels including those without platelet-activating factor showing the influence of platelets in the formation of the clot under the conditions tested. Inhibition of platelet aggregation with c7E3 (abciximab, ReoPro) also induced a much-prolonged activated clotting time, and a similar finding was seen with blood from a patient with Glanzmann's thrombasthenia confirming the need for platelet aggregation and/or the glycoprotein (GP) IIb-IIIa complex. In contrast, the interaction of GP Ib with von Willebrand Factor was not of major importance, since inhibition of this interaction with the anti-GP Ib murine monoclonal antibody, ALMA-12, did not modify the activated clotting time. Furthermore, the activated clotting time measured for patients with an acquired defect in von Willebrand Factor activity were unchanged. Finally, inhibition of thromboxane A2 formation by aspirin did not influence the results of this test. Globally, the Hemostatus test was able to detect major abnormalities of GP IIb-IIIa function in the presence or absence of platelet-activating factor.

Abciximab↗
PubMed1999

[Medico-legal dimension of informed consent in medicine].

The practice of the medical arts is more and more becoming framed by laws and regulations. Concurrently, the civil liability in the medical field has also been deeply changed, in particular by reversing the charge of proof of the information given to the patient. After having been reminded of the place in the juridical arsenal of informed consent to a medical procedure, its value is discussed regarding the explanations given by the physicians. Guidelines for a forensic appraisal, with the aim of evaluating and appreciating the information received by the patient, are proposed. Recent judiciary decisions about refusal of care, especially blood transfusions, are discussed.

France↗
PubMed1999

[Cellular energy metabolism: physiologic and pathologic aspects].

Cellular homeostasis requires permanent energy production and consumption. Adenosine triphosphate (ATP) is the major energy component for the cell. Its synthesis occurs mainly in mitochondria where the oxidative phosphorylations realise the coupling between oxygen consumption and phosphorylation of adenosine diphosphate. The anaerobic production of ATP plays an important role in the intermediary metabolism. The enzymatic complexes of the mitochondrial respiratory chain are energy transducers acting as proton pumps. In cardiomyocytes, the phosphocreatine circuit allows a substrate channelling between mitochondria and myofibrils. This metabolic compartmentation explains the difficulties of studying energetic metabolism in the beating heart and the lack of correlation between cardiac function and the usual energy parameters. Mitochondria are a potential site of action of anaesthetic agents. Lipophilic local anaesthetics impair cellular energy metabolism and mitochondrial ATP production. Such effects could be associated with toxic effects of these molecules. NMR or near-infrared spectroscopy are non invasive techniques for monitoring energetic metabolism in vivo. Clinical applications are developed for analysing brain, muscle or cardiac function in physiological and pathological conditions.

Adenosine Triphosphate↗
PubMed1998

[Left ventricular diastolic function: physiology, physiopathology, evaluation, therapy, consequences of anesthesia].

With the exception of cardiac surgery, the acute disturbance of the left ventricular diastole occurs mainly in the elderly. Today it represents 30 to 40% of congestive cardiac failures, however with a lower mortality than for acute systolic disturbances. Generally indicated are relaxation anomalies, proto-mesodiastolic mechanism and problems with compliance, an indicator of the pressure/volume diastolic relationship. Invasive techniques remain the standard method. Doppler echocardiography is becoming increasingly important for the assessment of diastolic function. In most cardiopathies, relaxation anomalies occur early, whereas compliance disturbances are mainly associated with advanced cardiac diseases. During anaesthesia, adverse events (auricular fibrillation, hypovolaemia) may worsen a fragile situation. Anaesthetic agents, in particular volatile agents, act on the ventricular diastole. Long-term therapy of diastolic anomalies includes agents amending left ventricular hypertrophy. Emergency therapy has not yet been systematised.

Aged↗
PubMed1998

[Preoperative evaluation of hemorrhagic risk].

Evaluation of bleeding risk before surgery requires both precise knowledge of epidemiological data relating to haemostasis disorders and a true clinical approach to help guide the diagnosis. The patient's individual and familial history is recovered during both the interview with the anaesthesiologist and the clinical examination. Preoperative haemorrhage risk prevalence is 1/40,000 patients in patients with asymptomatic congenital haemostasis disorders with low bleeding and 1/2,000 patients for acquired asymptomatic haemostasis disorders. Deficits in haemostasis factors, i.e., congenital disorders with haemorrhage potential, have an overall prevalence of 1/6,500 patients. Whatever the clinical case, haemorrhage disorders will arise in patients with either congenital or acquired bleeding abnormalities without symptoms. To work in close collaboration with haemobiologists and to request appropriate biological screening tests, it is therefore important to take into account prevalence data according to the surgical environment from which the patient will benefit.

Blood Loss, Surgical↗
PubMed1998

Impact of heterozygosity for the chemokine receptor CCR5 32-bp-deleted allele on plasma virus load and CD4 T lymphocytes in perinatally human immunodeficiency virus-infected children at 8 years of age.

The CCR5 gene encodes one of the major human immunodeficiency virus type 1 (HIV-1) coreceptors. A 32-bp deletion in this gene (delta ccr5) is associated with relative resistance to disease progression in heterozygous HIV-1-infected persons. The effect of this mutation on virologic and immunologic parameters was determined in a cohort of 45 perinatally HIV-1-infected children prospectively followed after 5 years of age. At a median age of 8.3 years, heterozygous children had significantly lower virus load than homozygous children (median, 3.3 vs. 4.1 log copies/mL, P < .009) and higher percentages of CD4 T cells (median, 26% vs. 17%, P < .07). However, there was no discernible influence of the CCR5 genotype on the percentages of CD8 T cells (P < .27) or on HIV-specific cytotoxic T lymphocyte activities (P < .65). There was a trend for lower rates of progression to AIDS (CDC stage C) in heterozygous children. These data confirm a major role for the CCR5 coreceptor in HIV-1 pathogenesis in children.

Acquired Immunodeficiency Syndrome↗
PubMed1996

[A study of practice patterns of albumin administration in surgical patients by anesthetists].

The establishment of guidelines has to take into account the current practice patterns. For the preparation of the consensus conference organized by the French Society of Anesthesia and intensive care (SFAR) on the prescription of albumin, an interview with a questionnaire was undertaken in order to assess the practice patterns of anaesthetists during the perioperative period. A group of 498 anaesthetists were interviewed during a congress. Two out of three prescribe albumin. In case of haemorrhage, the decision to administer albumin depends on the limits for using other colloids (for 65% of the responders), the amount of blood loss (46%) and albuminaemia (for only 26%). In other cases, albumin is mainly administered in the burn patient and for recurring ascite; albuminaemia is a decision criterion for one anesthetist out of two. About 25% of them use a 20% concentration, another 25% of them a 4% concentration and the remaining 50% use both concentrations. Adverse effects have been seen in less than 5% of the responders. These data have been presented at the consensus conference and can also be used for the assessment of the impact of the guidelines after their publication.

Adult↗
PubMed1996

Reduction in requirements for allogeneic blood products: nonpharmacologic methods.

BACKGROUND: Various strategies have been proposed to decrease bleeding and allogeneic transfusion requirements during and after cardiac operations. This article attempts to document the usefulness, or lack thereof, of the nonpharmacologic methods available in clinical practice. METHODS: Blood conservation methods were reviewed in chronologic order, as they become available to patients during the perisurgical period. The literature in support of or against each strategy was reexamined critically. RESULTS: Avoidance of preoperative anemia and adherence to published guidelines for the practice of transfusion are of paramount importance. Intraoperatively, tolerance of low hemoglobin concentrations and use of autologous blood (predonated or harvested before bypass) will reduce allogeneic transfusions. The usefulness of plateletpheresis and retransfusion of shed mediastinal fluid remains controversial. Intraoperatively and postoperatively, maintenance of normothermia contributes to improved hemostasis. CONCLUSIONS: Several approaches have been shown to be effective. An efficient combination of methods can reduce, and sometimes abolish, the need for allogeneic blood products after cardiac operations, inasmuch as all those involved in the care of cardiac surgical patients adhere thoughtfully to existing transfusion guidelines.

Animals↗