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Biomedical subjects

C Gibert

Publications and source records attributed to C Gibert.

At least 19 recordsLinked to original sources

Subpopulation of hyperresponsive polymorphonuclear neutrophils in patients with adult respiratory distress syndrome. Role of cytokine production.

To gain further insight into the pathogenesis of the adult respiratory distress syndrome (ARDS), we studied possible relationships among the activation status of circulating polymorphonuclear neutrophils (PMN), cytokine levels, and the severity of lung injury in 31 patients: 15 with ARDS, nine with severe pneumonia uncomplicated by ARDS, and seven mechanically ventilated with neither ARDS nor pneumonia. Nine healthy subjects served as controls. Using flow cytometry, we identified a subpopulation of PMN with an increased capacity to generate hydrogen peroxide after stimulation ex vivo in all three patient groups; significantly higher values were found in those with ARDS. The PMN stimulation index, a reflection of the degree of hyperresponsiveness, correlated with elevated levels of tumor necrosis factor-alpha (TNF alpha) in plasma, and both spontaneous and lipopolysaccharide-induced TNF alpha production by cultured monocytes. These biologic expressions of PMN activation and cytokine generation both correlated with indices of the severity of lung injury, but not with the overall clinical severity. In contrast, IL-6 and IL-1 beta showed little or no relationship with either the degree of lung injury or PMN hyperresponsiveness. We conclude that TNF-alpha-primed PMN may play a major role in the pathogenesis of ARDS-associated lung injury.

Flow Cytometry

Bronchoalveolar lavage for rapid diagnosis of the fat embolism syndrome in trauma patients.

OBJECTIVE: To evaluate the usefulness of bronchoalveolar lavage in establishing the diagnosis of the fat embolism syndrome in trauma patients with long-bone fractures. DESIGN: Case series. SETTING: Referral hospital. PATIENTS: Eighteen trauma patients with long-bone fractures, including 5 with definite fat embolism syndrome, 5 in whom the diagnosis had been clinically suspected but was impossible to confirm or exclude before bronchoscopy, and 8 with no clinical evidence of the syndrome. Control groups included 9 patients without previous trauma who developed the adult respiratory distress syndrome for various reasons and 15 normal volunteers. MEASUREMENTS AND MAIN RESULTS: Each patient had fiber-optic bronchoscopy with bronchoalveolar lavage, and the percentage of lavage cells containing intracellular fat droplets stained with oil red 0 were determined. In the five patients with definite fat embolism syndrome, light microscopic study of bronchoalveolar cells stained with oil red 0 showed many large intracellular fat droplets (mean percentage of cells containing fat droplets, 63%; range, 31% to 82%), whereas less than 2% of cells recovered by lavage from trauma patients with no clinical evidence of the syndrome, from patients with the adult respiratory distress syndrome, or from normal volunteers contained such inclusions. Use of the same technique in the five patients with possible fat embolism syndrome permitted the immediate identification of three patients in whom this diagnosis was later confirmed by subsequent autopsy or clinical follow-up. CONCLUSIONS: The identification of fat droplets within cells recovered by bronchoalveolar lavage in trauma patients may be a rapid and specific method for establishing the diagnosis of the fat embolism syndrome.

Adolescent

Prevalence of human immunodeficiency virus and hepatitis B virus in unselected hospital admissions: implications for mandatory testing and universal precautions.

The prevalence of human immunodeficiency virus (HIV) and hepatitis B virus in serial unselected hospital admissions was determined to examine the potential efficacy of a system of universal blood and body fluid precautions versus a system based on selected or unselected screening. Serum was obtained from 616 (97%) of the 636 patients admitted during a 1-month period and interviews were completed on 540. Of the 616, 23 (3.7%) were confirmed positive for HIV, and 12 (2.0%) of 612 for hepatitis B surface antigen. Of 33 infected persons, only 8 were known to be positive on admission and only 22 were in "high-risk" groups; therefore, selective precautions would not have been effective. Mandatory testing would have required 1216 tests to identify 25 infected persons and would leave in doubt the presence of other transmissible diseases. On the basis of these data, it appears that universal precautions are a logical system of infection control.

Communicable Disease Control

Characterization of distal bronchial microflora during acute exacerbation of chronic bronchitis. Use of the protected specimen brush technique in 54 mechanically ventilated patients.

To obtain accurate information on distal bronchial microflora during acute exacerbation in patients with chronic bronchitis, we prospectively studied 54 such patients who had been receiving mechanical ventilation because of hypercapnic respiratory failure. Fiberoptic bronchoscopy using a protected specimen brush (PSB) was performed on each patient within the first 24 h after admission. Cultures of protected brush specimens demonstrated no growth in 27 patients (50%). With the exception of fever (38.2 +/- 0.8 versus 37.7 +/- 0.6 degrees C; p less than 0.05), the initial severity of the episode of exacerbation was similar in patients with and without infection. A total of 44 organisms were isolated in the 27 patients with positive cultures; the predominant pathogens were Hemophilus spp. and Streptococcus spp. (involved in 74% of cases), but other organisms were isolated in 12 of 27 patients. Mortality rates, duration of mechanical ventilation, and duration of hospitalization were not significantly different between patients with bronchial microflora treated with appropriate antimicrobial therapy (n = 27) and patients without bronchial microflora either receiving empirical antibiotic therapy (n = 18) or not (n = 9). These data suggest that distal bronchial infection due to the usual pathogens, as far as shown by protected specimen brush cultures, may not be the sole or even the predominant cause of acute exacerbation of chronic bronchitis in patients requiring mechanical ventilation.

Acute Disease

Incidence and morbidity of cytomegaloviral infection in patients with mediastinitis following cardiac surgery.

To determine the incidence and morbidity of infections with CMV associated with mediastinitis after conventional cardiac surgery, 115 consecutive adult patients with mediastinitis were evaluated with viral cultures of blood and urine. Shedding of CMV was seen in 29 patients (25 percent) within a mean period of 37 +/- 22 days after cardiopulmonary bypass. Viremia was documented in 79 percent (23) of these 29 patients. Acute renal failure and enzymatic abnormalities (AST and LDH) were significantly more common in patients with virologically proven infection with CMV (p less than 0.05). In patients who survived the initial period of bacterial infection, major differences in their clinical course were observed according to their virologic status. After the 15th day of hospitalization following the débridement, the persistence of local infection was more frequent (p less than 0.05) and the mortality was higher (p less than 0.01) in CMV-infected patients. Moreover, the mean duration of hospitalization in the ICU for survivors was 69 +/- 36 days in viral shedders, compared with 48 +/- 27 days in nonshedders (p less than 0.05). Infection with CMV in mediastinitis occurs frequently and is associated with persistence of local infection, prolonged hospitalization, and increased late mortality.

Antibodies, Viral

Fiberoptic bronchoscopy in ventilated patients. Evaluation of cardiopulmonary risk under midazolam sedation.

One hundred seven acutely ill ventilated patients were prospectively studied to ascertain the severity and frequency of alterations in gas exchange and hemodynamic parameters during brief bronchoscopy. Sedation was performed using midazolam (0.1 mg/kg IV) without topical anesthesia. An average decline in PaO2 of 26 percent was observed at the end of the procedure, compared to the baseline value, and this was associated with a mild increase in PaCO2 in spite of the use of a special adapter. Alterations in mean systolic blood pressure appeared to be modest, consisting of a 10 percent decrease from the control level, related to sedation, and a 10 percent rise from baseline during the procedure, associated with a concomitant mild tachycardia. At that time, central hemodynamic measurements performed in a subset of 31 patients showed a significant increase in cardiac output associated with higher pulmonary wedge pressure. Fourteen patients developed hypoxemia of less than 60 mm Hg on FIO2 adjusted to 0.8. Of the ten risk factors univariately associated with hypoxemia, only the presence of ARDS (p less than 0.001) and "fighting" the ventilator during the procedure (p less than 0.05) remained significant after stepwise logistic regression. Attempts to prevent hypoxemia in critically ill patients should focus on inducing complete sedation, with careful attention to hemodynamic status, or providing maximal levels of oxygen to the ventilator (or both).

Adult

Diagnosis of nosocomial pneumonia in intensive care unit patients.

The optimal technique for diagnosing nosocomial bacterial pneumonia in critically ill patients cared for in the intensive care unit remains unclear, especially in the subgroup of patients requiring mechanical ventilation. An important advance has been the development of the protected specimen brush technique. We and others have demonstrated that secretions obtained using this technique and evaluated by quantitative cultures are useful in distinguishing patients with and without pneumonia. However, this procedure has important limitations in that results are not available immediately and in that a few false negative or false positive results may be observed. Recently, the use of bronchoalveolar lavage has been suggested to be of value in establishing the diagnosis of pneumonia, since the cells and liquid recovered can be examined microscopically immediately after the procedure and are also suitable for quantitative culture. We believe that microscopic identification of bacteria within cells recovered by lavage may provide a sensitive and specific means for early and rapid diagnosis of pneumonia in this setting and that the lavage technique can be conveniently incorporated into a protocol along with the quantitative culture of samples obtained using the protected specimen brush. This combination will probably improve the overall accuracy of diagnosis while allowing the administration of prompt empiric antimicrobial therapy in the majority of patients with pneumonia.

Cross Infection

Effect of lonapalene on metabolism of exogenous arachidonic acid in human platelets.

Lonapalene was studied as a topical antipsoriatic agent on the basis of its inhibitory effect on 5-lipoxygenase. We studied the effect of lonapalene on the metabolism of exogenous arachidonic acid in washed platelet suspensions by RP-HPLC. Lonapalene was shown to inhibit platelet cyclooxygenase, with substrate diversion towards 12-HETE production. The pattern of inhibition was similar to that of indometacin, although lonapalene was about 1,000 times weaker. The dual inhibition of lonapalene and concomitant deviation of arachidonic acid metabolism may have potential implications, with regard to therapeutic indications and side effects, which deserve further study.

12-Hydroxy-5,8,10,14-eicosatetraenoic Acid

Pancuronium blood level monitoring in patients with tetanus.

Overdosage of muscle relaxant has been given as a possible explanation for the hypotensive episodes occurring during the management of tetanus. The aim of the present work was to study the pharmacokinetics of pancuronium during long term infusion. Pancuronium was administered to eight patients with severe tetanus for a period varying from 8 to 24 days. The concentration of pancuronium was measured daily in plasma and urine using a fluorimetric method. The plasma concentration varied from 0.27 to 0.48 microgram/ml. No tendency to accumulation was observed. The plasma concentration fell rapidly below the level associated with muscle relaxation when pancuronium was discontinued. This absence of accumulation can be explained by a rapid elimination of pancuronium through the kidney according to a process of ultrafiltration.

Adolescent

[Echocardiographic diagnosis of 4 cases of tricuspid valve endocarditis].

Four tricuspid endocarditis cases are reported. Echocardiography found, four times, large vegetations on the tricuspid leaflets leading to the diagnosis. The degree of tricuspid insuffisancy was appreciated by the RV/LV ratio. Successive echos have permitted to survey the evolution and specially to establish a clear decrease of abnormal tricuspid echoes succeeding to pulmonary embolisms. In the four cases, surgery confirmed the diagnosis.

Adolescent

[Traumatic rupture of the aortic valve. Echocardiographic aspects. Apropos of a case].

The appearance of a diastolic murmur in a pyrexial patient 15 days after trauma was suggestive of infectious endocarditis. This diagnosis was excluded, especially by echocardiography, and the aortic incompetence was attributed to the trauma. The value of echocardiography and the features of other reported cases are discussed with referrence to this case.

Accidents, Traffic

[Severe pneumococcal infections of adults. 100 cases collected in three years (Claude Bernard Hospital, Paris) (author's transl)].

After retrospective in intensive care unit of 100 severe cases of pneumococcal infection in three years, the authors analyse the circumstances of onset (occurring in autumn of winter), the general status (without evident high risk population), the symptomatology (84% of meningitis, 30% of pneumonia), the origin of infection (essentialy otitis media in meningitis). The case fatality rate is 39%. Frequency of multiple visceral localisations and of bacteremias is emphasized.

Adolescent

IgM and IgG antibody responses in rabies encephalitis.

Immunological survey of 3 patients with proved rabies encephalitis shows three interesting facts. 1) An IgM local synthesis, sometimes proportionally higher than IgG local synthesis, is observed in 8 CSF (among 13 investigated) and detected early, during the first week of the disease for 2 patients. 2) A relative poor IgG response is noted; this response is absent in one and decreasing in the 2 others patients despite their progressive aggravation. 3) A very little elevation of blood nucleic antibodies is detected in 5 CSF only. This very poor synthesis of antinucleic IgG contrast with their common increase in viral encephalitis. Thus, a viral immunosuppression may be discussed in rabies encephalitis, which may contribute to the lethal prognosis.

Encephalitis