Search PubMed⌕ Search

Biomedical subjects

F Caron

Publications and source records attributed to F Caron.

At least 19 recordsLinked to original sources
PubMed2006

[Co-infection with Mycobacterium tuberculosis and Pneumocystis jiroveci in a patient without HIV infection].

INTRODUCTION: Co-infection with Pneumocystis jiroveci and Mycobacterium tuberculosis is rarely reported in patients without HIV infection. CASE REPORT: We report the case of a 30 year old woman admitted to hospital for respiratory distress associated with a diffuse infiltrative pneumopathy. Corticosteroid therapy had been started two months earlier for suspected pulmonary sarcoidosis. Fibreoptic bronchoscopy and broncho-alveolar lavage produced evidence of Mycobacterium tuberculosis and cysts of Pneumocystis jiroveci. HIV serology was negative. Clinical progress was satisfactory following anti-tuberculous and anti-fungal therapy. CONCLUSION: Pneumocystis pneumonia is rare in subjects without HIV infection and is most often associated with a pathology or treatment leading to depression of cellular immunity. Corticosteroid treatment, even of short duration, presents the greatest risk. Systematic antibiotic prophylaxis should be considered in relation to the immune status of the patient. Co-infection with the tubercle bacillus as reported here is exceptionally rare.

Adult↗
PubMed2005

[Pneumoperitoneum and pneumomediastinum complicating non-invasive ventilation].

INTRODUCTION: Pneumoperitoneum is known to be a rare complication of invasive mechanical ventilation. However it has not previously been described as a consequence of non-invasive ventilation. CASE REPORT: The authors report a case of pneumoperitoneum associated with pneumomediastinum occurring in a 64-year-old patient treated for 3 years with bilevel ventilation via a nasal mask (expiratory pressure = 9 cm H2O, inspiratory pressure = 15 cm H2O) for obesity hypoventilation syndrome. Respiratory and gastroenterological investigations did not demonstrate a cause for this complication which resolved spontaneously following the cessation of ventilation. Nine months later, clinical deterioration and a worsening of blood gas parameters led to a recommencement of non-invasive mechanical ventilation at the same levels as previously. Over two years of follow up there have been no clinical or radiological signs of a recurrence of pneumomediastinum or pneumoperitoneum. CONCLUSION: In the absence of any other explanation, barotrauma due to nasal ventilation appears to be the most likely explanation for this complication.

Humans↗
PubMed2004

Determinants of severity for superficial cellutitis (erysipelas) of the leg: a retrospective study.

BACKGROUND: Superficial cellulitis (erysipelas) of the leg is a frequent infectious disease with a favorable outcome, whereas some patients present a serious disease. The determinants of severity for superficial cellulitis (erysipelas) of the leg have not yet been clearly established. In order to determine the characteristics of patients presenting with severe superficial cellulitis of the leg, we analyzed patients with favorable and unfavorable outcome. METHODS: The records of 167 patients referred to Rouen University Hospital for non-superficial cellulitis of the leg were analyzed. Two severity groups of patients were retrospectively defined. Patients in the severe group either died secondary to infection during hospital stay or were hospitalized for a duration at least equal to the 90th percentile (i.e., >21 days of hospitalization). The remaining patients were considered as presenting with non-severe cellulitis. Potential determinants of severity were analyzed by univariate and multivariate analysis based on logistic regression. RESULTS: From univariate analysis, the following general factors were positively associated with severity: advanced age, arterial hypertension, diabetes mellitus, elevated leukocytosis, and elevated neutrophilia. The local factors associated with severity were ulcer of the leg and arteriosclerosis obliterans of the leg. From multivariate analysis, only age (P=0.004), diabetes mellitus (P=0.01), and leukocytosis (P=0.04) appeared to be independently associated with severity. A close to significant association was also found with arteriosclerosis obliterans of the leg (P=0.07). Whereas general complications occurred more frequently in the severe group, no such difference was observed for local complications. CONCLUSIONS: Determinants of severity for superficial cellulitis of the leg include high age and associated medical conditions. Aged patients and patients with diabetes mellitus, elevated leukocytosis, or possibly arteriosclerosis obliterans of the leg should preferably be hospitalized for specific care of associated conditions to avoid the occurrence of general complications.

Journal Article↗
PubMed2004

Evaluation of a theoretically based AIDS/STD peer education program on postponing sexual intercourse and on condom use among adolescents attending high school.

The effectiveness of an intervention based upon the theories of Ajzen and Triandis was evaluated among 698 junior and 306 senior high school students. The intervention to juniors was offered by senior students who were trained during a course integrated into the school curriculum. Respondents in the control and experimental groups completed a questionnaire at baseline and 9 months after the program. Compared to junior respondents in the control group, those in the experimental group positively modified their attitude, perceived behavioral control, personal normative beliefs, perceived role beliefs, anticipated regret and intention with respect to postponing sexual intercourse and with respect to condom use, as well as perceived self-efficacy to negotiate both behaviors. Compared to senior respondents in the control group, those in the experimental group showed a significant positive modification of all the above variables except perceived behavioral control (indirect measure), anticipated regret and intention with respect to postponing sexual intercourse. At post-test, seniors in the experimental group were more likely to use condoms on a regular basis than those in the control group. Program effects occurred among both sexes, but a few differences in response were observed among males and females. Results suggest this type of theory-based program is effective in modifying psychosocial variables related to postponing sexual intercourse and related to condom use among adolescents. Personal involvement in designing intervention appears to be effective in modifying the behavior of peer educators.

Adolescent↗
PubMed2001

Relaxation and modulation of cyclic AMP production in response to atrial natriuretic peptides in guinea pig tracheal smooth muscle.

Relaxation and modulation of cyclic AMP production in response to atrial natriuretic peptides were investigated in epithelium-denuded guinea pig tracheal rings, treated with indomethacin (5 microM) and phosphoramidon (1 microM) and contracted with histamine (3 microM). Atrial natriuretic peptide (ANP) was a more potent relaxant than C-type natriuretic peptide whereas ANP-(4-23) was inactive suggesting the involvement of ANP(A) receptors in the relaxant effect of ANP. ODQ (1H-[1,2,4]oxadiazolo[4,3-A]quinoxalin-1-one, 10 microM), a selective inhibitor of soluble guanylyl cyclase, markedly inhibited the relaxant response to sodium nitroprusside. The relaxant response to ANP was not altered by ODQ demonstrating the involvement of particulate guanylyl cyclase. ANP-induced relaxations, as well as sodium nitroprusside-induced relaxations, were similarly potentiated by rolipram (4-(3-(cyclopentyloxy)-4-methoxyphenyl)pyrrolidin-2-one, 3 microM), a type IV phosphodiesterase inhibitor, and by zaprinast (2-(2-propyloxyphenyl)-8-azapurin-6-one, 10 microM), a type V phosphodiesterase inhibitor. ANP-mediated response was unaffected by glibenclamide (10 microM), a selective blocker of ATP-sensitive K(+) channels, and by apamin (1 microM), a selective blocker of small-conductance Ca(2+)-activated K(+) channels. Iberiotoxin (100 nM) extensively prevented the relaxant effect of ANP suggesting the activation of large-conductance Ca(2+)-activated K(+) channels. In addition, ANP (10 nM) and ANP-(4-23) (100 nM) significantly reduced forskolin (1 microM)-stimulated cAMP accumulation suggesting, for the first time, the presence of functional ANP(C) receptors in guinea pig airway smooth muscle. However, relaxations to forskolin and to isoproterenol were not altered in the presence of ANP-(4-23) or ANP demonstrating that the inhibitory effect of ANP-(4-23) and ANP on adenylyl cyclase was not sufficient to alter the functional response induced by these two activators of adenylyl cyclase.

Adenylyl Cyclases↗
PubMed2001

Successful treatment of metronidazole- and albendazole-resistant giardiasis with nitazoxanide in a patient with acquired immunodeficiency syndrome.

A case of metronidazole- and albendazole-resistant giardiasis in a patient with the acquired immunodeficiency syndrome was successfully treated with nitazoxanide (1.5 g twice a day for 30 days). Animal studies and in vitro assays showed that the isolate was resistant to both metronidazole and albendazole and susceptible to nitazoxanide.

AIDS-Related Opportunistic Infections↗
PubMed2001

[Acute infectious endocarditis].

Acute infective endocarditis are due to highly virulent microorganisms, such as Staphylococcus aureus, able to invade normal endocardium, causing fulminant local damages (valvular destruction) as well as general damages (sepsis, metastasis), so that clinical manifestations are usually dramatic. Empirical antimicrobial therapy must be given immediately, using combinations active against the most commonly encountered pathogens. Other treatments are frequently necessary: medical therapy for heart failure, surgery of valvular reconstruction or replacement, respiratory assistance and other supportive measures. Such management requires cooperation of several disciplines.

Anti-Bacterial Agents↗
PubMed2001

Cysteinyl leukotrienes are involved in angiotensin II-induced contraction of aorta from spontaneously hypertensive rats.

OBJECTIVE: Non specific lipoxygenase inhibitors have been reported to reduce the in vitro constrictor response and the in vivo pressor effect of angiotensin II in rats. The aim of this study was to assess the role of cysteinyl leukotrienes, in the vascular response to angiotensin II in spontaneously hypertensive rats (SHR). METHODS: Rings of thoracic aorta from SHR and normotensive Wistar-Kyoto rats (WKY) were compared in terms of contractile responses and release of cysteinyl leukotrienes in response to angiotensin II. RESULTS: Pretreatment with the specific 5-lipoxygenase inhibitor AA861 10 microM reduced the efficacy of angiotensin II in intact and endothelium-denuded aorta from SHR (% inhibition vs. control: 65+/-12.6% with endothelium (n=6), P<0.05; 43+/-7.2% without endothelium (n=6), P<0.05) but not in aorta from WKY. In addition, in aorta from SHR, the CysLT(1) receptor antagonist MK571 1 microM reduced by 55+/-6.1% (n=6, P<0.05) the contractile effects of angiotensin II in rings with endothelium but not in endothelium-denuded rings. Angiotensin II induced a 8.6+/-2.1-fold increase in cysteinyl leukotriene production in aorta rings from SHR with endothelium which was prevented by the AT(1) receptor antagonist losartan 1 microM but not by the AT(2) receptor antagonist PD123319 0.1 microM. In aorta rings from WKY, cysteinyl leukotriene production remained unchanged after exposition to angiotensin II. The cysteinyl leukotrienes (up to 0.1 microM) induced contractions in aorta rings from SHR but not from WKY. CONCLUSIONS: These data suggest that cysteinyl leukotrienes, acting at least in part on endothelial CysLT(1) receptors, are involved in the contractile response to angiotensin II in isolated aorta from SHR but not from WKY.

Angiotensin II↗
PubMed2001

Cysteinyl leukotrienes modulate angiotensin II constrictor effects on aortas from streptozotocin-induced diabetic rats.

Angiotensin II (Ang II) is a vasopressor peptide involved in the pathogenesis of cardiovascular diseases associated with diabetes mellitus. We have previously reported that the 5-lipoxygenase-derived products, particularly the cysteinyl leukotrienes (CysLTs), are involved in Ang II-induced contraction. In this study, we demonstrated that CysLTs contribute to the contraction elicited by Ang II in isolated aortas from streptozotocin-induced diabetic (SS) rats but not from insulin-treated diabetic rats, fructose-fed rats, or control rats. In an organ bath, pretreatment with the 5-lipoxygenase inhibitor (AA861, 10 micromol/L) reduced by 37.6+/-8.2% and 30.1+/-10.9% the Ang II-induced contractions in intact and endothelium-denuded aortic rings, respectively, from SS rats. In contrast, the CysLT(1) receptor antagonist (MK571, 1 micromol/L) or the dual CysLT(1)/CysLT(2) receptor antagonist (BAY-u9773, 0.1 micromol/L) did not affect Ang II-induced contraction. In addition, Ang II induced a 6.2+/-1.5-fold increase in CysLT release through the stimulation of the Ang II type 1 receptor. Furthermore, the urinary excretion of leukotriene E(4) was increased in SS rats (leukotriene E(4), 13.7+/-2.9 ng/24 h [SS rats, n=10] versus 1.5+/-0.5 ng/24 h [control rats, n=6]; P<0.0004). These data suggest the activation of the 5-lipoxygenase pathway in SS rats and the involvement of 5-lipoxygenase-derived products, particularly the CysLTs, in Ang II-induced contraction in aortas from SS rats through stimulation of CysLT receptors different from the well-characterized CysLT(1) or CysLT(2) receptor.

Angiotensin II↗
PubMed2000

The respiratory performance and survival of the bivalve Macoma balthica (L.) at the southern limit of its distribution area: a translocation experiment.

The hypothesis was tested that animals near their extreme Southern limits, due to high temperatures, have a high respiration rate, whereby they reach an extreme low weight-index and ultimately disappear. At estuarine stations the respiration rate of Macoma balthica (L.) (Baltic clam) did not show interseasonal changes, indicating seasonal acclimation, but within the season the respiration increased with increasing temperature, indicating the absence of short-term acclimation. In clams translocated from the Netherlands towards the Bidasoa estuary, 200 km South of their Southern distribution limit, their respiration rate was higher and weight-index lower than in specimens living in Dutch estuaries. Irrespective of an effect of the temperature, clams exposed in experiments to water from Bidasoa showed a higher respiration than clams exposed to water from the other stations. Moreover, at non-estuarine stations with a low food content, the clams showed reversed acclimation, i.e., the respiration rates in winter were much lower than summer rates, most probably a strategy to conserve energy by means of a depressed metabolism. A weight index of 5 mg DW/cm(3) and glycogen content of 2% DW are suggested as the minimal values below which the metabolic energy balance of Baltic clams becomes more negative and the clam population disappears. It was concluded that factors other than temperature influenced the respiration and weight-index of clams, and hence their presence or absence, e.g., food concentration, innate seasonal cycles, and possible pollutants in the water.

Journal Article↗
PubMed2000

In vitro synergistic effects of double and triple combinations of beta-lactams, vancomycin, and netilmicin against methicillin-resistant Staphylococcus aureus strains.

Several studies have previously reported synergistic effects between vancomycin and a given beta-lactam or a given aminoglycoside against methicillin-resistant Staphylococcus aureus (MRSA) strains. The aim of our study was to exhaustively compare the effects of different combinations of a beta-lactam, vancomycin, and/or an aminoglycoside against 32 clinical MRSA strains with different aminoglycoside susceptibility patterns. The effects of 26 different beta-lactam-vancomycin and 8 different aminoglycoside-vancomycin combinations were first studied using a disk diffusion screening method. The best interactions with vancomycin were observed with either imipenem, cefazolin, or netilmicin. By checkerboard studies, imipenem-vancomycin and cefazolin-vancomycin each provided a synergistic bacteriostatic effect against 22 strains; the mean fractional inhibitory concentration (FIC) indexes were 0.35 and 0.46 for imipenem-vancomycin and cefazolin-vancomycin, respectively. The vancomycin-netilmicin combination provided an indifferent effect against all of the 32 strains tested; the mean of FIC index was 1. 096. The mean concentrations of imipenem, cefazolin, netilmicin, and vancomycin at which FIC indexes were calculated were clinically achievable. Killing experiments were then performed using imipenem, cefazolin, netilmicin, and vancomycin at one-half of the MIC, alone and in different combinations, against 10 strains. The vancomycin-netilmicin regimen was rarely bactericidal, even against strains susceptible to netilmicin. The imipenem-vancomycin and cefazolin-vancomycin combinations were strongly bactericidal against six and five strains, respectively. The addition of netilmicin markedly enhanced the killing activity of the combination of cefazolin or imipenem plus vancomycin, but only for the MRSA strains against which the beta-lactam-vancomycin combinations had no bactericidal effect. It is noteworthy that the latter strains were both susceptible to netilmicin and heterogeneously resistant to methicillin.

Anti-Bacterial Agents↗
PubMed2000

[Titration of an effective positive pressure level in the treatment of obstructive sleep apnea syndromes using continuous positive pressure ventilation].

The efficacy of continuous airway positive pressure ventilation with a nasal mask mainly depends on the appropriateness of the effective positive pressure level. Conventionally, this level is determined from polysomnographic recordings using progressively increasing pressure levels to determine the point where episodes of apnea, hypopnea and snoring regress in all sleep phases and in all body positions. Since the first description of this method, many other titration methods have been proposed. Some use sophisticated signals such as the analysis of respiratory exertion level or limitation of inspiratory flow to provide a more precise titration which is particularly useful in cases where the classical titration method is insufficiently effective. Inversely, simplified methods have been examined from an economic point of view. These methods do not require the presence of a technician in a specialized laboratory where the waiting list for diagnostic tests is often long. Recordings during naps or short nights have been proposed for the more severe cases. Likewise titrations during simple polygraphy recordings or with an autoCPAP device have been shown to be effective in one-night laboratory recordings. Much work remains to be done to determine the effectiveness of these methods when used in the patient's home as well the long-term effects.

Humans↗
PubMed2000

[Titration of the level of effective positive pressure in the treatment of obstructive sleep apnea syndromes with continuous positive pressure].

The efficacy of continuous airway positive pressure ventilation with a nasal mask mainly depends on the appropriateness of the effective positive pressure level. Conventionally, this level is determined from polysomnographic recordings using progressively increasing pressure levels to determine, the point where episodes of apnea, hypopnea and snoring regress in all sleep phases and in all body positions. Since the first description of this method, many other titration methods have been proposed. Some use sophisticated signals such as the analysis of respiratory exertion level or limitation of inspiratory flow to provide a more precise titration which is particularly useful in cases where the classical titration method is insufficiently effective. Inversely, simplified methods have been examined from an economic point of view. These methods do not require the presence of a technician in a specialized laboratory where the waiting list for diagnostic tests is often long. Recordings during naps or short nights have been proposed for the more severe cases. Likewise titrations during simple polygraphy recordings or with an autoCPAP device have been shown to be effective in one-night laboratory recordings. Much work remains to be done to determine the effectiveness of these methods when used in the patient's home as well the long-term effects.

Home Care Services↗
PubMed2000

[Muco-cutaneous colonization and nosocomial infections caused by methicillin-resistant Staphylococcus aureus and Acinetobacter baumanii in intensive care patients].

This study was designed to assess the frequency and risk factors for colonization with MRSA and A. baumanii in the intensive care unit, and to analyse the relationship between colonization and infection with MRSA or A. baumanii. During a 24-day survey period, colonization was studied weekly with nasal, throat and digit skin swabs; nosocomial infections were routinely monitored according to CDC recommendations. Clinical data and invasive procedures were registered during a one-year non-epidemic period; 103 ICU patients hospitalized for more than 7 days were prospectively included. We investigated acquired colonization and nosocomial infection with SAMR or A. baumanii for 87 patients not colonized by SAMR or A. baumanii on admission. The colonization acquisition rate was 56% for MRSA and 27% for A. baumanii. Infection incidence (cases per 1,000 patient-days) was 6.46 for MRSA and 1.61 for A. baumanii. On univariate analysis, acquired MRSA colonization was associated with longer ICU stays, longer mechanical ventilation and longer central venous catheterization. Multivariate analysis only showed an association with longer ICU stay. Acquired A. baumanii colonization was associated with SAPSII, longer mechanical ventilation, and longer central venous catheterization in univariate analysis. Multivariate analysis only showed an association with SAPSII and longer mechanical ventilation. In this study, SAMR or A. baumanii infections were not associated with colonization or clinical setting or invasive procedures.

Acinetobacter↗
PubMed1999

Functional assessment of rat aorta after cold storage in different media.

Cold storage is frequently used to store isolated blood vessels for a limited period of time. However preservation of vascular smooth muscle and endothelial functions is time and medium-dependent. The present study was designed to compare the reactivity of rat aorta before and after cold storage for 24 and 48 h in one of four different solutions consisting of Hepes-buffered Krebs solution, Belzer solution, Krebs solution, and Eurocollins solution. Smooth muscle and endothelial functions of the rat aorta were assessed using in vitro isometric tension measurement. The results obtained for vessels preserved for 24 and 48 h were compared with those for vessels studied immediately after harvesting. Sensitivity and maximum contraction to KCl and norepinephrine were not altered in rat aorta preserved up to 48 h in Hepes-Krebs and Belzer solutions. In contrast, the amplitude of contraction elicited by KCl was significantly reduced by 50% and 77% in aorta stored for 24 and 48 h in Krebs solution and by 77% and 96% in those stored in Eurocollins solutions. Similarly, the maximal contraction elicited by norepinephrine was significantly reduced by 60% and 45% in arteries stored for 24 and 48 h in Krebs solution and by 34% and 86% in those stored in Eurocollins solution. In contrast, cold storage in the different media did not alter the relaxations elicited by sodium nitroprusside and forskolin. The endothelium-dependent relaxations in response to acetylcholine were not statistically modified after preservation up to 48 h in Hepes-Krebs solution. In contrast, the maximal relaxations to acetylcholine were significantly decreased after storage for 24 and 48 h in Belzer, Krebs and Eurocollins solutions. These results suggest that among the four media studied, Hepes-Krebs solution is the most suitable medium for the storage of blood vessels under hypothermic conditions.

Animals↗
PubMed1999

[Thyroid manifestations of sarcoidosis: a case report].

Sarcoidosis is a systemic disease with many localizations. Thyroid involvement has been often described but rarely confirmed histologically. A common immune mechanism appears to be the cause. Thyroid sarcoidosis should be envisaged in patients with a thyroid nodule and mediastino-pulmonary involvement. We report the case of a 63-year-old woman with no past history who was hospitalized for dyspnea. Explorations evidenced a cold thyroid nodule associated with diffuse interstitial lung disease and mediastinal node enlargement. Pathology examination disclosed the sarcoid nature of the thyroid nodule and the lung lesions.

Biopsy↗