Search PubMed⌕ Search

Biomedical subjects

P Charbonneau

Publications and source records attributed to P Charbonneau.

At least 19 recordsLinked to original sources
PubMed2004

Out-of-equilibrium dynamical fluctuations in glassy systems.

In this paper we extend the earlier treatment of out-of-equilibrium mesoscopic fluctuations in glassy systems in several significant ways. First, via extensive simulations, we demonstrate that models of glassy behavior without quenched disorder display scalings of the probability of local two-time correlators that are qualitatively similar to that of models with short-ranged quenched interactions. The key ingredient for such scaling properties is shown to be the development of a criticallike dynamical correlation length, and not other microscopic details. This robust data collapse may be described in terms of a time-evolving "extreme value" distribution. We develop a theory to describe both the form and evolution of these distributions based on a effective sigma model approach.

Journal Article↗
PubMed2004

[Epidemiology and diagnosis of respiratory syncitial virus in adults].

INTRODUCTION: Respiratory syncytial virus (RSV) is rarely searched for in respiratory infections in adults. This study assessed its frequency and diagnosis. METHODS: Three separate studies were conducted in adults presenting with (1) a flu-like illness, (2) a lower respiratory tract infection in the community, and (3) a severe pneumonia requiring hospitalisation. The diagnosis of RSV infection was sought by PCR in all cases, and compared to antigen detection and culture in two studies. RESULTS: RSV was identified in 20 (11.7%) of 170 influenza-vaccinated adults suffering from flu-like symptoms. In the 270 cases of non-severe lower respiratory tract illnesses in the community, viruses were identified in 86 (31.8%) cases, with RSV accounting for 13 (4.8%). In the 164 cases of acute bronchitis, a virus was detected in 64 (36.7%) of which 11 (6.3%) were RSV, 37 (21.3%) rhinovirus, 5 influenza viruses A and B, and 12 other viruses. In the 60 cases of infective exacerbations of chronic bronchitis, rhinovirus was detected in 9 (15%) and para-influenza 3 virus in 2 cases. In the 21 acute pneumonia's, 1 RSV, 1 influenza virus A and 2 rhinovirus cases were detected as well as 1 RSV, 1 parainfluenza 3 viruses and 4 rhinovirus cases in the 11 lower respiratory tract illnesses in patients with pre-existing lung disease. There were overall 19 viral and bacterial associated infections. Finally, in the 51 acute pneumonias hospitalised with respiratory distress syndrome, a virus was identified in 17 (33.3%) cases, including 3 (5.5%) RSV, 6 influenza A, 3 rhinovirus, 2 adenovirus, 2 herpes simplex virus and 1 cytomegalovirus. There were 6 bacterial-associated infections, and 4 were hospital-acquired. All RSV-infected patients were old people and had chronic pulmonary or cardiac disease. CONCLUSIONS: In adults, RSV is a frequent cause of flu-like symptoms. It can sometimes cause lower respiratory tract illness, which can be severe, and should be considered in the differential diagnosis in such cases. The PCR method is a particularly effective diagnostic test, but as yet is not routinely available.

Adult↗
PubMed2003

Hyperreninemic hypoaldosteronism: a possible etiological factor of septic shock-induced acute renal failure.

OBJECTIVE: Hyperreninemic hypoaldosteronism has been described in critically ill patients. The present study investigated the plasma aldosterone concentration (PAC) in septic shock patients and its relationship with clinical course. DESIGN AND SETTING: Prospective descriptive study in a medical intensive care unit (ICU) of a university hospital. PATIENTS: Forty-six consecutive patients with septic shock as defined by the ACCP/SCCM criteria. INTERVENTION: A corticotropin stimulation test, followed by treatment with low doses of hydrocortisone and fludrocortisone. MEASUREMENTS AND RESULTS: Plasma renin activity, PAC, and cortisol levels were measured before and after the test. PAC measurements were repeated for 1 week. Relevant clinical and laboratory variables were recorded for ICU stay. Patients were divided into two groups according to PAC/renin activity ratio: above 2 (n=24 patients) and below 2 n=22). Patients with PAC/renin activity less than 2 had higher total volume of infused fluid, serum creatinine level, and fractional excretion of sodium values; aldosterone and serum creatinine were negatively correlated. Hypoaldosteronism was reversible within 1 week. Duration of ICU stay (p=0.0026) and the need for renal replacement therapy (p=0.0021) were greater in the group with PAC/renin less than 2. CONCLUSIONS: Transient hyperreninemic hypoaldosteronism is common in patients with septic shock. These abnormal aldosterone levels are associated with greater sodium and fluid depletion and are followed by enhanced incidence of acute renal failure requiring renal replacement therapy and prolonged length of stay in ICU.

Acute Kidney Injury↗
PubMed2003

Corticosteroids as adjunctive treatment in Austrian's syndrome (pneumococcal endocarditis, meningitis, and pneumonia): report of two cases and review of the literature.

This report describes two cases of Osler's triad of pneumonia, meningitis, and endocarditis, as a result of Streptococcus pneumoniae infection, also called Austrian's syndrome. In the first patient, a 51 year old non-alcoholic man, the aortic valve was affected and needed to be replaced in an emergency operation. The mitral valve was affected in a 70 year old woman without underlying disease, who only benefited from medical treatment. Both patients received corticosteroids, either dexamethasone followed by low doses of hydrocortisone and fludrocortisone, or only hydrocortisone and fludrocortisone, at the onset of the illness, and their outcome was favourable. These case reports focus on the presentation, prognosis, and therapeutic options for this severe syndrome.

Adrenal Cortex Hormones↗
PubMed2001

Energy barriers to rotation in axially chiral analogues of 4-(dimethylamino)pyridine.

The barriers to enantiomerization of a series of axially chiral biaryl analogues of 4-(dimethylamino)pyridine (DMAP) 1-10 were determined experimentally by means of dynamic HPLC measurements and racemization studies. The barriers to rotation in derivatives 1-6 (based on the bicyclic 5-azaindoline core) were lower than those in the corresponding derivatives 7-10 (based on the monocyclic DMAP core). Semiempirical (PM3), ab initio Hartree-Fock (HF/STO-3G), and density functional theory (DFT/B3LYP/6-31G*) calculations reveal that these differences in barriers to rotation are the result of differing degrees of hybridization of the non-pyridyl nitrogen in the enantiomerization transition states (TSs). The importance of heteroatom hybridization as a factor in determining nonsteric contributions to barriers to rotation in azabiaryls of this type is discussed.

Journal Article↗
PubMed2001

Prophylactic antibiotics are not indicated in clean general surgery cases.

BACKGROUND: In assigning risk of infection, the traditional wound classification system has been replaced by the National Nosocomial Infection Surveillance (NNIS) system. NNIS classification is determined by procedure length, wound cleanliness, and ASA status. To date, no prophylactic antibiotic guidelines have been proposed for the NNIS system. METHODS: Clean general surgery cases were retrospectively reviewed in our hospital for infection and prophylactic antibiotic use. These cases were then stratified per the NNIS system. RESULTS: One thousand twenty-three clean general surgery cases had 16 (1%) surgical site infections. The infection rate in NNIS class 0, 1, and 2 cases not given prophylactic antibiotics was 1.21%, 3.03%, and 0%, respectively. The infection rate in NNIS class 0, 1, and 2 cases given prophylactic antibiotics was 0.94%, 2.44%, and 6.67%, respectively. CONCLUSIONS: No statistically significant decrease in infection rate was demonstrated by us using prophylactic antibiotics, regardless of the NNIS classification in clean general surgery cases.

Antibiotic Prophylaxis↗
PubMed1999

Elective laparoscopic management of sigmoid diverticulitis. Results in a series of 110 patients.

BACKGROUND: The aim of this study was to evaluate the results of elective laparoscopic treatment of sigmoid diverticulitis. METHODS: Between November 1991 and February 1998, 110 patients were treated by elective laparoscopic colectomy for sigmoid diverticulitis. The main data recorded were postoperation pain, return of bowel function, operation time, duration of hospital stay, and early and late complications. RESULTS: Mean age of patients was 63 years (range, 36-83 years). Nine patients (8.2%) required conversion to laparotomy because of severe adhesions, inflammatory process, or obesity. The mean operation time was 167 min. Return of bowel function was 2.3 days. Mean postoperation stay was 8.2 days. There was no perioperation death, and the morbidity rate was 7.3%, with two complications related to the laparoscopic approach (1 trocar site bowel incarceration and 1 small bowel fistula). Of the patients with complications, four (3.6%) needed reoperation. During the follow-up (6-79 months), no incisional hernia was observed. CONCLUSIONS: Laparoscopic colectomy for sigmoid diverticulitis is feasible and safe in more than 90% of cases. Benefits of the laparoscopic approach are the improved early postoperation course and the reduction of parietal sequelae.

Adult↗
PubMed1998

Evaluation of laparoscopic management of common bile duct stones in 220 patients.

BACKGROUND: The aim of this study was to evaluate the feasibility and results of laparoscopic management of common bile duct stones (CBDS). METHODS: From October 1990 to November 1996, 220 patients with CBDS have been managed laparoscopically. CBDS were suspected or diagnosed preoperatively in 130 patients (59.1%) and at intraoperative cholangiography (IOC) in 90 patients (40.9%). A transcystic duct extraction (TCDE) was attempted in 112 patients and a primary choledochotomy in 108 patients. RESULTS: TCDE was successful in 77 cases (68.8%). The 35 failures were treated by 29 laparoscopic choledochotomies, 1 intraoperative and 5 postoperative endoscopic sphincterotomies (ES). A choledochotomy was thus performed in 137 cases and was successful in 133 cases (97.1%). The four failures were managed by three laparotomies and one postoperative ES. The overall success rate was 95.5% (210/220). There was 4 deaths (0.9%) within the 1st postoperative month in ASA 3 patients and the morbidity rate was 9.1% (20/220). There were 7 residual stones (3.2%). CONCLUSIONS: Laparoscopic desobstruction of CBDS appears to be safe and effective and has the advantage to be a single-stage procedure. It could become in the future with refinement of instrumentation and skill of surgeons the best treatment for the majority of patients harboring CBDS.

Adult↗
PubMed1997

[Results of laparoscopic treatment of diverticular sigmoiditis. Apropos of 85 cases].

The authors report their experience of laparoscopic management of sigmoid diverticulitis in 86 patients operated from november 1991 to december 1996. Out of them, 9 patients in whom sigmoiditis was revealed by an acute complication underwent an emergency procedure and 76 patients were operated electively. The mean hospital stay was 9.2 days (range 5 to 15 days) and the mean time of passage of flatus was 2.4 days. Benefits of laparoscopic management of sigmoid diverticulitis consist of improvement of early postoperative course and absence of abdominal wall sequelae. The decrease in mean hospital stay in not significant except for patients who underwent an emergency procedure.

Adult↗
PubMed1994

Teicoplanin: a well-tolerated and easily administered alternative to vancomycin for gram-positive infections in intensive care patients.

A prospective, randomized multicentre study was conducted in order to evaluate the potentially superior tolerability profile of teicoplanin plus netilmicin compared with vancomycin plus netilmicin in patients in ICUs. We considered that these glycopeptides have been shown to have comparable efficacy and that comparative tolerability is of paramount importance, particularly in severely ill patients. A total of 56 patients were enrolled into the study (36 males and 20 females). Twenty-four patients were included in the teicoplanin plus netilmicin group (15 males, 9 females: mean age 56.8 years). The mean simplified acute physiological score (SAPS) was 9.4 (range 4-20). Thirty-two patients were randomized to receive vancomycin plus netilmicin (21 males, 11 females; mean age 56.4 years). The mean SAPS was 9.3 (range 2-16). Septicaemia was the most common infection (14 cases in each group). Most infections were caused by Staphylococcus aureus or coagulase-negative staphylococci. The mean daily doses were: for teicoplanin, 457 mg (6.7 mg/kg); for vancomycin, 1678 mg (24.4 mg/kg); and for netilmicin 263.3 mg (3.9 mg/kg) in the teicoplanin group and 248 mg (3.8 mg/kg) in the vancomycin group. The trough levels of teicoplanin in the serum remained mostly between 7 and 10 mg/l, while more fluctuation was seen in patients receiving vancomycin. The mean trough levels of netilmicin in the serum were 1.2 (SD 0.9) mg/l in the teicoplanin group, compared with 1.7 (SD 1.4) mg/l in the vancomycin group (NS: p > 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Review of piperacillin/tazobactam in the treatment of bacteremic infections and summary of clinical efficacy.

One method of resistance to beta-lactam antimicrobials involves production of beta-lactamases, enzymes that render the beta-lactam ineffective. Beta-lactamase inhibitors have been combined with beta-lactam antibiotics to combat beta-lactamase producing organisms. One such agent, piperacillin/tazobactam, has been shown to be safe and effective therapy for infections usually treated with a combination of antibiotics such as polymicrobial and nosocomial infection, and has been used for empiric therapy in cases of serious infection. A survey of the literature shows that piperacillin/tazobactam is a safe and efficacious therapy for bacteremia as well as soft tissue, intra-abdominal, and lower respiratory tract infections. When combined with an aminoglycoside, it is also useful in the treatment of severe nosocomial respiratory infections.

Bacteremia↗
PubMed1993

[Extrapulmonary and disseminated pneumocystosis in HIV infection].

Three cases of extrapulmonary disseminated Pneumocystis carinii infection are reported. All 3 patients had HIV infection with less than 50 CD4 lymphocytes per cubic millimeter and were having aerosols of pentamidine as prophylactic treatment of pneumocystosis. P. carinii may invade numerous organs and in particular the liver, spleen and bone marrow. Extrapulmonary lesions, often pan-symptomatic, are to be feared in deeply immunodepressed patients receiving prophylactic aerosols of pentamidine. Infection of the choroid can be detected by systematic ophthalmoscopy. An early diagnosis raises hopes of a good, if temporary, response to treatment.

AIDS-Related Opportunistic Infections↗