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Biomedical subjects

G Capellier

Publications and source records attributed to G Capellier.

28 records · Page 2Linked to original sources

Alterations of myocardial and vascular adrenergic receptor-mediated responses in Escherichia coli-induced septic shock in the rat.

OBJECTIVES: To investigate responsiveness to exogenous catecholamines in rat bacteremic shock by studying both myocardial and vascular functional parameters; to determine in the same study the relationship of these parameters with other relevant biological parameters of the adrenergic pathway, such as myocardial beta-adrenergic receptors and cyclic adenosine monophosphate (cAMP); and to indirectly approach the roles of tumor necrosis factor-alpha (TNF-alpha) and nitric oxide. DESIGN: Experimental, comparative study. SETTING: Laboratory in a university hospital. SUBJECTS: Male Sprague-Dawley rats, weighing 270 to 320 g. INTERVENTIONS: Intravenous injection of live Escherichia coli DH5 alpha (2 x 10(10) organisms/kg) or saline (0.6 mL) and comparison of the two groups. MEASUREMENTS AND MAIN RESULTS: Mean arterial pressure and heart rate (HR) were recorded, and circulating TNF-alpha concentrations were measured, during the first 3 hrs after E. coli administration. Myocardial and vascular functional parameters were obtained, respectively, from Langendorff-perfused hearts and isolated aortic rings. Adrenergic biochemical parameters (catecholamines, density and affinity of beta-receptors, and isoproterenol-stimulated myocardial cAMP) were determined 3 hrs after E. coli injection. Mean arterial pressure decreased within 5 to 60 mins after bacteria injection and returned to basal levels in the last 2 hrs; HR was unchanged. Serum TNF-alpha concentrations peaked at 120 mins (7333 +/- 672 pg/mL) and were still increased at 3 hrs. Plasma concentrations of epinephrine and norepinephrine were significantly (p < .05) increased. Baseline values for differential left ventricular pressure and coronary flow were significantly (p < .0001, p < .001, respectively) reduced; HR remained unchanged. Isoproterenol induced a similar increase in differential left ventricular pressure and in HR. There was no decrease in the functional myocardial response to adrenergic stimulation. beta-adrenergic receptors were similar in density and in affinity in the two groups. Isoproterenol-stimulated myocardial cAMP was significantly (p < .01) reduced compared with the control group. In aortic rings, bacteria administration significantly (p < .01) shifted the dose-response curve to norepinephrine to the right, both in the presence and absence of endothelium. NG-monomethyl-L-arginine significantly increased the contractions to attain the control level: p < .001 in presence of endothelium; p < .05 in absence of endothelium. CONCLUSIONS: In ex vivo experiments, 3 hrs after E. coli injection, vascular responsiveness was sharply decreased. This impaired response was improved by inhibition of nitric oxide. The heart, nevertheless, was still able to modulate its inotropic and chronotropic response to isoproterenol, even though an impaired beta-adrenergic-receptor stimulation of cAMP was already present.

Animals↗

L-NAME aggravates pulmonary oxygen toxicity in rats.

Exposure to high oxygen concentration leads to acute lung injury and death in rats after 72 h. The pathophysiology of this phenomenon relies on several mechanisms, including alteration of vascular reactivity, recruitment and activation of neutrophils and alveolar macrophages, production of cytokines and excess production of free radicals. In addition to its potent vasodilating effect, nitric oxide (NO) has also been reported to prevent free radical-mediated damage. We wanted to determine whether NG-nitro-L-arginine methyl ester (L-NAME), a NO synthase inhibitor, might modulate oxygen toxicity. In rats exposed to continuous high oxygen concentration, we studied the effect of administration of 50 mg.kg-1 of intraperitoneal L-NAME twice a day on the first day of oxygen exposure. L-NAME resulted in earlier death, since 57% of the animals exposed to oxygen and injected with L-NAME died within 60 h as compared to 22% of the animals exposed to oxygen and treated with saline (p < 0.01). Haematocrit and bronchoalveolar lavage fluid protein were also significantly increased in animals exposed to oxygen and receiving L-NAME. The lung water content was higher in the oxygen-exposed groups (p < 0.01) and slightly decreased by L-NAME (p < 0.05). Thiobarbituaric acid reactive substances (TBARS) were elevated in plasma (p < 0.01) and decreased in lung (p < 0.001) of oxygen-exposed animals, but no significant effect of L-NAME was observed. NG-nitro-L-arginine methyl ester had a deleterious effect in rats exposed to hyperoxia, which might suggest that endogenous nitric oxide has a protective role against hyperoxia-induced pulmonary lesions.

Animals↗

Use of pulsed-field gel electrophoresis as an epidemiologic tool during an outbreak of Pseudomonas aeruginosa lung infections in an intensive care unit.

OBJECTIVE: A retrospective study was performed to evaluate the use of DNA polymorphism analysis by pulsed-field gel electrophoresis (PFGE) in assessing the rate of exogenous contamination during an outbreak of Pseudomonas aeruginosa lung infections in an intensive care unit ICU. Another goal was to determine the risk factors, involved in the outbreak. DESIGN: Rectal swabs and tracheal secretions were cultured from all patients upon admission and thereafter once a week throughout their stay in the ICU. Resistance patterns were determined in all P. aeruginosa isolates. We determined the serotypes, pyocin types, plasmid profiles and total DNA macrorestriction patterns for isolates. The restriction fragment length polymorphism (RFLP) of Dra I total DNA digest was studied by PFGE. A retrospective case-control study was performed to determine the risk factors for P. aeruginosa bronchopulmonary colonization. SETTING: The study was carried out in the medical ICU of Besancon University Hospital (France). RESULTS: The typability, stability and reproducibility of phenotypic markers were not completely satisfactory. Only the RFLP profile satisfied all the criteria for a good typing technique. In four of the 17 patients, P. aeruginosa strains with the same DNA pattern were found. Among the previously reported risk factors for hospital-acquired bronchopulmonary infections, only invasive procedures were determined by multivariate analysis to be significant in our study group. The oropharynx and the bronchial tract are the most likely endogenous sources. CONCLUSION: PFGE-RFLP is a valuable tool for the epidemiologic study of P. aeruginosa. This typing method revealed that exogenous contamination is not always the major source of P. aeruginosa lung infections in mechanically ventilated patients in ICUs.

Analysis of Variance↗

Pilot clinical trial of an anti-TNF alpha monoclonal antibody for the treatment of septic shock.

OBJECTIVE: To determine the safety and pharmacokinetics of an anti-tumour necrosis factor (TNF alpha) monoclonal antibody in the treatment of septic shock, and to evaluate the biological evolution of cytokine response. DESIGN: Open-label, prospective, pilot trial with escalating doses of a murine monoclonal antibody (B-C7) directed against TNF alpha. SETTING: University medical centre intensive care unit. PATIENTS: Nine patients with septic shock, who received standard supportive care and antimicrobial therapy in addition to the anti-TNF alpha antibody. INTERVENTIONS: Patients were treated intravenously with one of three escalating doses of B-C7 monoclonal antibody (MoAb): 0.4 mg/kg, 0.8 mg/kg, 1 mg/kg. RESULTS: MoAb was well tolerated despite the development of human anti-mouse antibodies (HAMA) for each patient; B-C7 plasma levels were dose-dependent. At study entry, TNF alpha and IL-6 levels were detected in six and seven patients respectively; IL-1 levels were low and interferon-gamma was undetectable. CONCLUSIONS: No side effects were noted during treatment regardless of the dose used; however, further studies are needed to determine the clinical efficacy of this agent in septic shock.

APACHE↗

[Osteochonroplastic tracheopathy associated with dermatomyositis: apropos of a case].

We report a case of a 35 year-old-man with dermatomyositis associated with tracheopathia osteoplastica. The swallowing perturbation secondary to myositis and airway involvement by tracheopathia induced fatal outcome. Tracheopathia osteoplastica is a rare disease and occurs exclusively in men over the age of 50. The association of two rarest disease is not a fortuitous event. The common pathogenic factor may be, in this case, the occupational exposure to silicon.

Adult↗

[Pharmacological interactions between diltiazem and thiopental. A study on an electrophysiological model of guinea pig isolated papillary muscle. Value of positive inotropic agent].

This study was designed to assess in vitro the effects of Thiopental alone and Thiopental--Dobutamine association on control and on Diltiazem pretreated papillary muscle. The Diltiazem treatment do not increase the negative inotropic effect of Thiopental but the effect of Dobutamine is less important in pretreated group. The Diltiazem treatment protect to arrhythmogenic action of Thiopental and Thiopental-Dobutamine association.

Animals↗

[Diagnosis of post-traumatic pleural effusion].

A rare case of post-traumatic pleural effusion is reported. A 19 year old male patient was admitted after a road traffic accident with a scalp wound, femoral shaft fracture and haematuria related to a ruptured bladder. Shortly after extubation following bladder surgical repair, the patient had to be reintubated because of acute respiratory failure. A large left-sided pleural effusion was then diagnosed. The liquid was sero-haematic and contained a high concentration of creatinine (839 mumol.l-1). Thoracic CT scan and intravenous urography displayed a left epirenal collection and a dilatation of the upper urinary tract with rupture of the renal pelvis. The surgical treatment of this urinothorax consisted of the rupture repair of the posterior diaphragm and of the urinary tract.

Adult↗

[Purulent pleurisy caused by anaerobic bacteria. A retrospective study of 19 cases].

A retrospective clinical, biological, radiological and evolutive study of 19 cases of pleural empyema caused by anaerobic organisms diagnosed between 1980 and 1986 was carried out. These 19 cases accounted for 30.6 p. 100 of all cases of pleural empyema diagnosed during the same period. A local or general contributory factor was found in all patients; false passage, gastrointestinal pathology and buccal or dental diseases were the most frequent aetiological circumstances. The clinical picture was rather torpid, with a body temperature below 38 degrees C in 42 p. 100 of the cases, which delayed the diagnosis: the mean time interval between onset and diagnosis was 20 days. In nearly one half of the cases, blood stained expectoration was present and air-fluid levels were visualized at standard radiography and computerized tomography, which is the best exploratory method to evaluate the size and appearance of the pleural lesion, to guide percutaneous drainage and later to assess possible sequelae. The predominant anaerobic flora consisted of Gram-positive cocci and Bacteroides spp; in 70 p. 100 of the cases the anaerobic organism(s) was (were) sensitive to penicillin G. The course of the disease was favourable in all patients. Surgery was performed in 3 of the 19 patients on account of chest wall gangrene due to Clostridium perfringens in 1 case and of the presence of multiple fluid pockets making drainage ineffective in 2 cases.

Adult↗