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Biomedical subjects

C Guérin

Publications and source records attributed to C Guérin.

At least 37 records · Page 2Linked to original sources
PubMed1996

Serum and erythrocyte magnesium in critically ill patients.

OBJECTIVES: To evaluate the prevalence of serum and erythrocyte magnesium (Mg) abnormalities in patients on admission to the intensive care unit (ICU) and to test the hypothesis that low levels of Mg are associated with a higher mortality. DESIGN: Prospective study. SETTING: 14-bed ICU in a 1000-bed teaching hospital. PATIENTS: 179 consecutive patients admitted over a 4-month period. MEASUREMENTS: Total serum Mg (Mgs) and erythrocyte Mg (Mge) were determined on admission by atomic absorption spectrophotometry. Severity of illness was assessed by Acute Physiology and Chronic Health Evaluation (APACHE) II and the number of organ system failures (OSF) during the first 24 h. The patients were followed up until discharge from hospital. MAIN RESULTS: On admission, 79 patients (44%) were hypomagnesemic and 10 (6%) were hypermagnesemic. A low level of Mge was observed in 119 patients (66%). In patients with similar APACHE II scores and OSF numbers, more of those with hyperMgs died during their ICU stay. However, the Mge value on admission did not correlate with patient outcome. CONCLUSIONS: We confirm the high prevalence of Mgs abnormalities as well as Mg deficiency on admission to a medical ICU. Low levels of Mgs and Mge are not associated with higher fatality. HyperMgs was associated with patient death.

APACHE↗
PubMed1996

[Respiratory mechanics of chronic obstructive lung disease in acute respiratory insufficiency].

Respiratory mechanics abnormalities in patients with chronic obstructive pulmonary disease (COPD) in acute respiratory failure (ARF) consist of the followings : 1) expiratory flow limitation, 2) marked increase in airway resistance, 3) dynamic hyperinflation. As a results, both resistive and elastic loads to the respiratory muscles are increased. These abnormalities, which are already present in stable COPD patients, are considerably more marked in ARF. Our contribution was to systematically describe the passive mechanical properties of lung and chest wall of COPD patients tracheally intubated, mechanically ventilated, sedated-paralyzed for ARF. Mechanical properties, i.e. resistances and elastances, were obtained from the rapid end-inspiratory airway occlusion technique during constant-flow inflation. This method allows to partition the resistance into its two components, namely the interrupter resistance, which reflects airway resistance, and additional tissue resistance, which pertains to time constant unequalities and/or viscoelastic behavior. We also determined the static and dynamic elastances of both lung and chest wall. Static intrinsic positive end-expiratory pressure (PEEPi) was obtained from end-expiratory airway occlusion. By changing, for one breath, inflation flow, at constant volume, and inflation volume, at constant flow, we investigated the time, and hence the frequency dependence of resistance and elastance. In addition, we divided the inspiratory work of breathing into its four components which are the PEEPi component, the static work, the purely resistive work and the additional work. Finally we compared our results with those of normal anesthetized and paralyzed subjects. We found that airway resistance was markedly higher in COPD, as were also the additional resistance and the dynamic elastance of the lung. Additional resistance and dynamic elastance of lung and chest wall exhibited a marked frequency dependence in COPD. Shortening the inspiratory time could result not only to reduce the hyperinflation but also to increase expiratory flow through the increased dynamic pulmonary elastance. The inspiratory work was twice higher in COPD than in normals because of the PEEPi and the resistive components. Due to their flow and volume dependence, the results of resistances and elastances should be standardized.

Acute Disease↗
PubMed1995

Differential short-term transduction efficiency of adult versus newborn mouse tissues by adenoviral recombinants.

We demonstrated different transduction efficiency in several major organs of the immature (newborn) versus mature (adult) mice using adenoviral recombinants containing expression cassettes for either firefly luciferase or bacterial beta-galactosidase reporter genes. The studied tissues included skeletal muscle, heart, brain, lung, kidney, and liver. The transduction efficiency in all tissues, especially skeletal muscle, was significantly less in adults than in newborns, with two exceptions. In the heart, transduction efficiency was the same in newborns and adults, while in brain, it was greater in the adult than in the newborn. The cited differences in transduction efficiencies between newborn and adult tissues applied approximately equally to both reporter genes. The alpha v integrin level showed the same trend as the transduction efficiency in all tissues, except the heart. Polymerase chain reaction showed a specific adenoviral product in proportion to the reporter gene expression in muscle, heart, and brain. The results of this study should be considered in designing gene therapy strategies in genetic diseases.

Adenoviridae↗
PubMed1995

[Severe acute buflomedil poisoning].

The severity of the acute intoxication from buflomedil, a vasodilator with papaverinic and alpha-adrenolytic effects, remains generally underestimated. We report the case of a 18-year-old girl who ingested a high amount of buflomedil. Two hours later, she developed seizures and ventricular arrhythmias. On admission to the ICU, she was in circulatory arrest followed by deep coma with mydriasis (GCS = 3). Buflomedil blood concentration, 2 hours after admission, was 97.3 mg.L-1. Toxicological screening for other drugs was negative. Therapy included external chest compressions tracheal intubation, mechanical ventilation, epinephrine and gastric lavage. The haemodynamic status improved within the first 24 h, although she remained comatose until the fifth day. She was discharged the eight day after her admission. This observation demonstrates that the potential severity of buflomedil poisoning is mainly due to early cardiac complications. Treatment remains purely supportive.

Acute Disease↗
PubMed1995

Role of metformin accumulation in metformin-associated lactic acidosis.

OBJECTIVE: To investigate the role of metformin accumulation in the pathophysiology of metformin-associated lactic acidosis. RESEARCH DESIGN AND METHODS: We used high-performance liquid chromatography to measure plasma metformin concentrations in 14 patients who experienced lactic acidosis (pH < 7.35 and lactate concentration 5 > mmol/l) while receiving chronic metformin treatment. Their treatment was generally based on alkalinization and dialysis therapy. RESULTS: Clinical shock and/or evidence of tissue hypoxia was found in all patients with the exception of one who had a nonsteroidal anti-inflammatory drug-induced anuria. Ten patients had significant metformin accumulation (plasma metformin concentrations 4.1-84.9 mg/l, normal value 0.6 +/- 0.5 mg/l before drug intake), generally because of failure to withdraw metformin despite intercurrent pathological conditions affecting its renal elimination (serum creatinine concentrations ranging from 269 to 1,091 mumol/l). There was no metformin accumulation (plasma metformin 0.03-0.7 mg/l) in the four other patients, who had less severe renal failure (serum creatinine 140-349 mumol/l). The severity of the patient's general condition did not predict early hospital mortality (death before discharge from the intensive care unit) even in patients in shock. Whereas it was high in those without metformin accumulation (only 1 of 4 patients recovered), early hospital mortality was low in the 10 patients with metformin accumulation and was not related to its extent (3 patients died with end-stage hepatic failure or cardiac failure). Correlation studies showed a positive correlation between serum creatinine and plasma metformin and between plasma metformin and arterial lactate but, for the latter correlation, only in patients with metformin accumulation. CONCLUSION: Metformin-associated lactic acidosis is not necessarily due to metformin accumulation; true type B (aerobic) lactic acidosis, i.e., without an apparent associated hypoxic factor, seems exceptional. Neither the severity of the clinical picture nor the degree of metformin accumulation predicted survival; rather, the prognosis was dependent upon the severity of the associated pathological conditions.

Acidosis, Lactic↗
PubMed1995

[The use of gene amplification for the detection of the Aujeszky's disease virus in the sperm of boars].

The aim of the present study was to specify the experimental conditions for the use of the polymerase chain reaction (PCR) in the detection of the pseudorabies virus in boar semen. Boar semen was artificially contaminated by Aujeszky's disease virus and submitted to the PCR. The seminal plasma fraction of the semen was found inhibitory for PCR. An incubation of the samples with proteinase K followed by an extraction of the viral DNA on a glass matrix was shown to be able to remove the inhibition. The method was simple, rapid and allowed the detection of around 370 viral DNA sequences per microliter of sample. The detection of the amplified DNA by a specific enzymatically labelled probe could improve the sensitivity of the method.

Animals↗
PubMed1993

Distribution of BHV1 in fractions of semen from a naturally infected bull.

The aim of the present study was to investigate the distribution of BHV1 (Bovine Herpesvirus 1) in the semen from a naturally infected bull and more particularly, to determine if there were viral particles associated with sperm that could interfere with in-vivo or in-vitro fertilization. Frozen semen from a single ejaculate that had been previously identified as being contaminated with BHV1 was used. The contents of 12 ministraws were mixed. Two aliquotes served as controls, the first was held at 0 degrees C in ice water while the second was held at 4 degrees C in the centrifuge during the procedure. The remaining semen was separated into seminal plasma and sperm cell fractions by centrifugation. The seminal plasma was kept at 0 degrees C until viral titration. The pellet was treated by 10 consecutive washes in PBS and by a trypsin treatment after the fifth wash. Subsequently, the last pellet was macerated to break the cell membranes. Aliquotes for viral titration were taken from all washing fluids, from pellets after the fourth, sixth and tenth washes, and from the last crushed pellet. These aliquotes were kept in ice water until titration. The virus was titrated on secondary cell cultures of fetal calf kidney. The titers were 4.3, 4.2 and 4.4 log TCID50/ml, respectively, in the 2 controls and the seminal plasma. Titers declined from 3.8 log to 0 from the first to the tenth wash. The titer was 2.2 log in the resuspended pellet of sperm cell fraction prior to trypsin treatment. No virus was detected in the sixth pellet, the tenth one or from the crushed cells. It was concluded that a significant proportion of the BHV1 particles was associated with the sperm cells. Ten washes and a trypsin treatment could remove the adsorbed virus. No viral particles were detected within the sperm cells.

Journal Article↗
PubMed1993

Lung and chest wall mechanics in mechanically ventilated COPD patients.

By use of the technique of rapid airway occlusion, the effects of inspiratory flow, volume, and time on lung and chest wall mechanics were investigated in 10 chronic obstructive pulmonary disease (COPD) patients mechanically ventilated for acute respiratory failure. We measured the interrupter resistance (Rint), which in humans reflects airway resistance; the additional resistances due to time constant inequality and viscoelastic pressure dissipations within the lungs (delta RL) and the chest wall; and the static and dynamic elastances of lung and chest wall. We observed that 1) static elastances of lung and chest wall in COPD patients were similar to those of normal subjects; 2) Rint of the lung was markedly increased and flow dependent in COPD patients, whereas Rint of the chest wall was negligible as in normal subjects; and 3) in COPD patients, delta RL was markedly increased at all inflation flows and volumes, reflecting increased time constant inequalities within the lungs and/or altered viscoelastic behavior. The results imply increased dynamic work due to Rint and delta RL and marked time dependency of pulmonary resistance and elastance in COPD patients.

Aged↗
PubMed1993

Partitioning of work of breathing in mechanically ventilated COPD patients.

In 10 sedated paralyzed mechanically ventilated chronic obstructive pulmonary disease (COPD) patients, we measured the inspiratory mechanical work done per breath on the respiratory system (WI,rs). We measured the tracheal and esophageal pressures to assess the lung (L) and chest wall (W) components of WI and used the technique of rapid airway occlusion during constant-flow inflation to partition WI into static work [Wst, including work due to intrinsic positive end-expiratory pressure (WPEEPi)], dynamic work due to airway resistance, and the additional resistance offered by the respiratory tissues. Although the patients were hyperinflated, the slope of the static volume-pressure relationships of the lung did not decrease with inflation volume up to 0.8 liter. WI,W was similar in COPD patients and normal subjects. All components of WI,L were higher in COPD patients. The increase in Wst,rs was due entirely to WPEEPi. Our data suggest that, during spontaneous breathing, COPD patients would probably develop inspiratory muscle fatigue, unless continuous positive airway pressure were applied to reduce WPEEPi.

Acute Disease↗
PubMed1992

[Diagnosis of caprine contagious pleuropneumonia: recent improvements].

Due to the difficulty in isolating Mycoplasma sp. type F38, two techniques for rapid detection are proposed in order to identify the presence of mycoplasmas of the mycoides group in samples of pleural fluid. A modification in the composition of isolation media promotes the growth of type F38 mycoplasmas and inhibits the growth of M. ovipneumoniae strains.

Animals↗
PubMed1992

[The visco-elastic behavior of the respiratory system during mechanical ventilation. Interpretation with the aid of a model].

The purpose of this review is to present an approach to the visco-elastic properties of the respiratory system in the mechanically ventilated patient through the method of occlusion of the airways at a constant inspiratory flow rate. The ideas of airways resistance, tissue resistance, static and dynamic elastance are defined from the theoretical point of view and also from the point of view of the occlusion method. A large part is given to the bicompartmental model describing the visco-elastic properties of the lung and of the thoracic wall. Recently carried out experimental studies both in healthy man and in disease have given results which seem to confirm the predictions made by this model. According to this system the lungs may be represented as a homogenous whole surrounded by visco-elastic components.

Airway Resistance↗
PubMed1992

[Evaluation of tolerance during intravenous administration of low dose of isosorbide dinitrate in the treatment of unstable angina].

The eventuality of tolerance was assessed in 19 patients with unstable angina treated by continuous intravenous infusion of 50 micrograms/min of isosorbide trinitrate (ISDN) in association with heparin and betablocker therapy. The tolerance phenomenon was evaluated by the hypotension produced by the ISDN infusion and by the amplitude of fall in blood pressure produced by an intravenous bolus of 1 mg of glyceryl trinitrate (GTN) according to the principle of crossed tolerance to the two nitrate derivatives. Under these conditions of administration, the authors observed partial attenuation of the blood pressure response to continuous ISDN infusion and absence of cross tolerance between ISDN and intravenous GTN. The co-prescription of intravenous N-acetylcysteine at a dosage of 10 g/24 hours in 10 of the 19 patients did not affect the blood pressure or the response to the GTN bolus compared with the 9 other patients who had received placebo after double-blind randomisation. The results of this study do not indicate if the maintenance of vascular sensitivity to nitrate derivatives at least for 72 hours, was related to the choice of a relatively low dose and/or the use of ISDN rather than another nitrate derivative, in particular glyceryl trinitrate. The use of intravenous ISDN at a low dose over a 3 day period in the usual conditions of prescription for unstable angina does not seem to induce a quantitatively significant phenomenon of tolerance.

Acetylcysteine↗
PubMed1990

[Ureteral stenosis in kidney transplantation].

The authors report 13 cases of ureteral or periureteral sclerosis in a series of 330 cases of renal transplantation (3.9%): they occurred early, were asymptomatic (except for anuria); the renal cavities were always dilated, the renal function always deteriorated; the treatment was essentially surgical without mortality and with a low complication rate but 23% of the transplants were lost because of urological complications at 18 months. The authors compare their series with the literature.

Adult↗
PubMed1990

[Transplantation and tumors of the kidney].

The authors report the case of a woman who was transplanted with a cadaveric kidney. It was a cyst on the kidney; a biopsy was performed: it was a carcinoma. The transplanted kidney was removed. The second case was a man, transplanted with a cadaveric kidney, with a tumor at the lower pole: a tumorectomy was performed: it was a angiomyolipoma.

Acute Kidney Injury↗