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Biomedical subjects

J P Lavigne

Publications and source records attributed to J P Lavigne.

At least 19 recordsLinked to original sources

Evolution of fluoroquinolone resistance among Escherichia coli urinary tract isolates from a French university hospital: application of the dynamic regression model.

Escherichia coli urinary tract isolates were collected in 1997-2003 from Nimes University Hospital in order to investigate long-term trends in antibiotic resistance and to explore the relationship between antibiotic use and the emergence of resistance. Time-series analysis (ARIMA models) and dynamic regression models were used to investigate relationships between antibiotic use and resistance to ofloxacin and ciprofloxacin. Significant increases were seen in the frequency of ofloxacin (8.9 to 16.7%) and ciprofloxacin resistance (6.2 to 10.1%) (p < 0.001). Using multivariate dynamic regression analysis, it was found that an increased use of one defined daily dose (DDD)/1000 patient-days for ofloxacin, ciprofloxacin and norfloxacin induced average increases of 0.81%, 0.65% and 0.53% in E. coli ofloxacin resistance (p < 0.01), with average delays of 4, 4 and 6 months, respectively. An increase of 1 DDD/1000 patient-days of ciprofloxacin, ofloxacin and norfloxacin use induced increases of 0.73%, 0.82% and 0.63% in E. coli ciprofloxacin resistance (p < 0.01), with average delays of 4, 4 and 5 months, respectively. The use of nalidixic acid was not associated significantly with an increase in resistance to fluoroquinolones by multivariate analysis.

Anti-Infective Agents↗

[Resurgence of syphilis: a prospective study at an University Hospital, Nimes].

BACKGROUND: Since 2000, the incidence of syphilis has increased in France. The study objective was to estimate the frequency of syphilis in Languedoc Roussillon region in Southern France. METHOD: The prospective study was conducted between January 1, 2003 and June 30, 2003 in different medical wards in a French University Hospital, Nimes. The diseased patients in this study answered to a questionnaire, providing epidemiological and socio-economic data, symptomatology and treatment-seeking behaviour. Blood specimens were tested for syphilis by the serological methods (TPHA, VDRL, FTA). RESULTS: In 6 months, serologic evidence of syphilis infection was found in 30 patients. Men were more than twice as likely as women to be infected with syphilis. Most men (64.7%) acquired the infection homosexually. Four women acquired infection during pregnancy. The mean age of study population was 46.3 years. 40.7% were married. Out of 27 cases, 70.4% cases had an associated sexually transmitted infection (HIV, hepatitis, herpes, and gonorrhoea). CONCLUSIONS: These data confirm the increase of syphilis in south of France and underline the importance of a permanent monitoring of sexually transmitted infection in target populations to allow a timely diagnosis and an appropriate treatment, and to plan preventive strategies.

Adult↗

Chronic rupture of abdominal aortic aneurysm manifesting as crural neuropathy.

Chronic rupture of abdominal aortic aneurysm (AAA) resulting in unusual clinical manifestations can occur if the resistance of structures surrounding the aorta is sufficient to contain hemorrhage. In this report, we describe five cases of chronic ruptured AAA in which the presenting feature was crural neuropathy. All patients were male with a mean age of 74 +/- 1.8 years. At the time of presentation, crural neuropathy had been ongoing for 3 to 9 weeks. In three cases, AAA was not initially suspected because an inadequate clinical examination was performed (not in the vascular surgery department) and because of the small diameter of the aorta in relation to the patient's morphology. Two patients had one episode of hypotension that was wrongly attributed to vagal attack. Abdominal CT scanning was always diagnostic of chronic rupture. In two cases, rupture was associated with erosion of the body of one or more vertebrae and laboratory evidence of inflammation, i.e., increase in sedimentation rate and fibrinogen level. The mean diameter of the AAA was 7.1 +/- 0.9 cm (range 5-10 cm). All patients underwent midline laparotomy, which was performed under emergency conditions in two cases, under semi-emergency conditions in one case, and electively in two cases. Perforation was consistently located on the posterolateral wall of the aorta and varied from 1 to 3 cm in length. Repair was performed using an aortobifemoral prosthesis in four cases, and a straight tube in one case. The patient who underwent emergency surgery died 4 days after the procedure. The remaining four patients recovered uneventfully and were discharged after 10 days. In the elderly, ruptured AAA should be included in the differential diagnosis of crural neuropathy. An episode of hypotension, regardless of its duration, in an elderly patient should be given serious consideration as a possible sign of ruptured AAA with ongoing retroperitoneal hemorrhage.

Aged↗

Use of cryopreserved arterial homografts for management of infected prosthetic grafts: a multicentric study.

The objective of this study was to evaluate the effectiveness of cryopreserved arterial homografts for management of prosthetic graft infection. Between October 1992 and July 1998, 90 patients (84 men) with a mean age of 64 years from six different hospitals were treated for prosthesis infection by in situ replacement using a cryopreserved arterial homograft (CAH). In 43 patients (47%), the primary procedure had been performed at a nonparticipating center. Prosthetic graft infection occurred early (i.e., within 1 month after the primary procedure) in 15 cases and late in 75 cases. In the late group, the mean interval between the primary procedure and CAH replacement was 34 months (range, 3 to 330 months). In 41 patients, infection was located in the aortic region, including 17 presenting with enteroprosthetic fistula (EPF). In 49 patients, infection was confined to the femoral, popliteal, or subclavian region. Bacteriologic cultures were positive for one or more germs in 75 patients and negative in 15. The surgical procedure consisted of complete or partial removal of the infected prosthetic graft, debridement, and in situ reconstruction using one or more CAH. Our results showed that management of prosthetic graft infection, a grave complication, using a CAH is a promising technique, especially for patients in stable condition prior to reconstruction.

Adult↗

[How I explore ... value of isotopic techniques in the detection of sepsis in valvular prostheses].

Vascular graft infection is a rare but serious complication of vascular surgery. The diagnosis is frequently difficult. White blood cell imaging (111In or 99mTc-HMPAO) is an adequate technique for detecting vascular graft infection. This is a sensitive and specific method and has some advantages in the detection of perioperative or low grade infection in comparison to conventional imaging. The usefulness of other techniques like the 18FDG-PET scan is studied, but not yet evaluated. We compare the different methods actually used by illustrating three case reports of vascular graft infection for whom the diagnosis was formally made by isotopic imaging.

Aged↗

Typical presentation of intramural aortic haemorrhage (IAH) with evidence of intimal tear at MRI and angiography.

A typical appearance of IAH was evidenced by CT and TEE in a 56-year-old hypertensive female suspected of developping classical acute aortic dissection (AAD). Further examination with MRI and aortography showed unequivocally the presence of an intimal tear in the aortic arch. This coexistence of intimal tear has never been evidenced preoperatively in patients with IAH. This observation demonstrates at the outset that IAH is part of the spectrum of AAD.

Aortic Dissection↗

Deletion of central alpha-helices in human apolipoprotein A-I: effect on phospholipid association.

In order to better understand the structure-function properties of apolipoprotein (apo) A-I, we have constructed and expressed three apoA-I mutants using a system previously described for the expression of human apolipoprotein A-I (Rec.-apoA-I). These mutants (corresponding to deletion of apoA-I residues 100-143, 122-165, 144-186) have been studied for their ability to form reconstituted apoA-I-containing lipoproteins (LpA-I) with POPC and DMPC, and for their structural and physical properties. Rec.- and native apoA-I can form homogeneous discoidal Lp2A-I over a wide range of POPC/apoA-I ratios [(20-130)/1] and exhibit sizes ranging from 9.5 to 10.5 nm. When recombined with varying POPC content [(20-130)/1, POPC/A-I)], the three mutants produce homogeneous discoidal Lp2A-I that contain a low POPC/A-I molar ratio [(20-40)/l for all mutants] and exhibit a nearly constant size [7.5-7.6 nm for delta (100-143) and 7.9-8.0 nm for the other two mutants]. Kinetics of association of these proteins with DMPC are similar for delta (100-143) and Rec.-apoA-I (t 1/2 of 4.0 and 4.4 min, respectively) but appear significantly reduced for delta (122-165) and delta (144-186) (t 1/2 of 7.5 and 6.9 min, respectively). While in the lipid-free form, all proteins have a similar thermodynamic stability with a very comparable free energy of unfolding (delta GD degree) for the alpha-helical structure, as determined by isothermal denaturation studies. delta-(100-143) has a significantly lower alpha-helical content (33%) as compared to the other proteins [40, 41, and 45% for Rec.-apoA-I. delta (122-165), and delta (144-186), respectively]. When associated to POPC, delta (122-165) and delta (144-186) have a higher alpha-helicity (63 and 63%) and an enhanced stability (2.5 and 2.3 kcal/mol, respectively) as compared to delta (100-143) (49% and 1.8 kcal/mol) and Rec.-apoA-I (52% and 1.9 kcal/mol). These results suggest that the amphipathic alpha-helices within residues 100-186 are directly involved in interactions with phospholipids. The helical region 100-121 appears to be more important to the stabilization of the lipid-apoprotein complex formed whereas helices within residues 122-186 appear to be critical to the initial rates of association of the apoprotein with DMPC. These data suggest that an important role of the central domain 100-186 may be to maintain the plasticity of apoA-I and its ability to form different classes of HDL particles. Therefore, it is likely that this region may also play an important role in the functional properties of this apoprotein.

Apolipoprotein A-I↗

Aneurysm of the ascending aorta after cardiac transplantation.

We report the case of a 57-year-old female cardiac transplant patient in whom an aneurysm of the recipient side of the ascending aorta developed 1 year after transplantation. Although a mycotic origin was the likely cause, histologic examination diagnosed an atherosclerotic aneurysm.

Aortic Aneurysm↗

Increased transcripts for B-type natriuretic peptide in spontaneously hypertensive rats. Quantitative polymerase chain reaction for atrial and brain natriuretic peptide transcripts.

The cardiac natriuretic peptide family includes atrial natriuretic factor and brain or B-type natriuretic peptide, also known as iso-atrial natriuretic factor (isoANF). Although these peptides contribute to cardiovascular homeostasis, their respective roles remain unclear. To study regulation of atrial natriuretic factor and isoANF gene expression during progression of hypertension, we developed a quantitative polymerase chain reaction protocol to measure their transcript level in spontaneously hypertensive rat (SHR) hearts. At the onset of hypertension, atrial natriuretic factor transcripts in 5-week-old SHR were 50% of those of age-matched Wistar-Kyoto (WKY) rats, whereas the level of isoANF transcripts was similar in atria and twofold higher in ventricles. Because atria are the major sites of atrial natriuretic factor gene expression and ventricles contribute predominantly to cardiac isoANF synthesis, total atrial natriuretic factor messenger RNA (mRNA) in the hearts of 5-week-old SHR was about 50% of that in WKY rats, and total isoANF mRNA content was already higher than in control rats. In left ventricles and ventricular septa, progression of hypertension led to a maximal increase of twofold and fourfold in atrial natriuretic factor and isoANF mRNA levels, respectively, with no detectable change in right ventricles. In the atria of older SHR, atrial natriuretic factor and isoANF mRNA levels were comparable to those of age-matched controls. These data indicate that, although increased blood pressure stimulates both atrial natriuretic factor and isoANF gene expression, regulation of the two natriuretic peptide genes is not temporally coordinated in all cardiac compartments. Furthermore, isoANF mRNA is already induced in the ventricles at the onset of the hypertensive stage, and in older SHR, the isoANF gene is hyperresponsive to progression of hypertension compared with atrial natriuretic factor. Thus, isoANF might represent a very sensitive marker of cardiac changes in hypertension.

Animals↗

[Mitral valve replacement in post-infarction rupture of the papillary muscle. Apropos of 13 cases surgically treated during the acute phase of infarction].

Between 1983 and 1988, thirteen patients (12 men and 1 women, average age 63 years) were operated in the acute phase of myocardial infarction for papillary muscle rupture (PMR). The rupture involved the posterior papillary muscle in 12 cases. The average left ventricular ejection fraction was 47 +/- 9 per cent (range 34 to 63%). Pulmonary capillary pressures ranged from 76 to 41 mmHg (average 35 mmHg). Eleven patients presented with acute pulmonary oedema and 7 had cardiogenic shock. Coronary arteriography showed triple vessel disease in 3 cases, double vessel disease in 7 cases and single vessel disease in 3 cases. Surgery was carried out on average 2.7 days after the rupture and 10 days after the initial infarct. In addition to mitral valve replacement (N = 13), 11 patients underwent a myocardial revascularisation procedure. The operative mortality was 15 per cent (N = 2). Papillary muscle rupture in the acute phase of myocardial infarction causes cardiac failure which is related more to the mechanical abnormality than to an alteration of left ventricular function. Considering the operative mortality and the natural history of PMR treated medically, the authors recommend early surgery as the only management which can improve the precarious haemodynamic status of patients with this complication.

Aged↗

Ventricles as a major site of atrial natriuretic factor synthesis and release in cardiomyopathic hamsters with heart failure.

The aim of the present study was to correlate in cardiomyopathic hamsters with congestive heart failure the levels of atrial and ventricular atrial natriuretic factor (ANF) messenger RNA (mRNA) with immunoreactive ANF (IR-ANF) plasma levels and the relative amount of IR-ANF released by the whole heart versus isolated ventricles in the Langendorff preparation. High-performance liquid chromatography analysis of the forms of ANF present in plasma and in the Langendorff effluent of whole heart versus isolated ventricles was also performed. As previously found for cardiac IR-ANF, the levels of ANF mRNA decreased gradually in atria and increased in an analogous fashion in ventricles with the severity of congestive heart failure. Plasma IR-ANF levels (C-terminal) were more elevated in moderate than in severe congestive heart failure, as were the IR-ANF levels in the Langendorff effluent of the whole heart. On the contrary, the effluent of isolated ventricles from animals in severe heart failure yielded more IR-ANF than that from hamsters in moderate heart failure. Thus, while the isolated ventricles from controls contributed 35.8% of IR-ANF released by the whole heart, ventricles from hamsters in moderate heart failure contributed 17.5%, and those from hamsters in severe heart failure contributed 73.9%. These results indicate that atrial cardiocytes contribute more IR-ANF than their ventricular counterpart in moderate heart failure and that ventricles are a major source of plasma IR-ANF in severe heart failure. Analysis of IR-ANF from plasma and the Langendorff effluent from whole hearts and isolated ventricles revealed that the ventricles are the major source of the propeptide (and of its cleaved products) found in the circulation of cardiomyopathic hamsters. These results suggest that ANF synthesis and secretion do not increase conjointly in atria but do increase in ventricles during congestive heart failure.

Animals↗

Cloning and expression of the atrial natriuretic factor gene.

Atrial natriuretic factor (ANF) is a 28-amino acid peptide hormone with potent natriuretic, diuretic and vasodilator properties. Isolation and DNA sequence analysis of rat and human cDNA clones revealed that ANF is synthesized from a 126-amino acid precursor which is highly conserved in both species. Southern blot analysis indicated that the ANF gene is present in a single copy per haploid genome. Both human and rat ANF genes were isolated and showed a similar structural organization which consisted of three exons and two introns. The ANF gene was localized to the short arm of human chromosome 1 and mouse chromosome 4. While atria are the major site of expression of the ANF gene in adult heart, other tissues like ventricles, lung, anterior pituitary, hypothalamus and adrenal synthesize ANF albeit to a much lower extent. In ventricles, ANF mRNA levels are 150 times lower than in atria. However, in cardiac hypertrophy or in congestive heart failure, ventricular ANF mRNA and peptide levels are dramatically (100-fold) increased both in animal models and in humans. This suggests that ventricles are a major site of ANF gene expression in certain pathophysiological conditions and that ANF is not an exclusively atrial peptide as was originally thought.

Animals↗

Expression of atrial natriuretic factor gene in heart ventricular tissue.

A novel peptide hormone, atrial natriuretic factor (ANF), was recently isolated and characterized in mammalian atria. This hormone has potent natriuretic diuretic and vasorelaxant activities. Since ANF bioactivity was initially found in atria but not in ventricles, it was assumed that the ANF gene is specifically expressed in atria. We now report that ANF mRNA is present in ventricular tissue as well as in atria. This is clearly demonstrated by in situ hybridization and by Northern blot analysis. Rat ventricular ANF mRNA concentration is a hundred-fold lower than in atria. As in atria, the 126 amino acids precursor form of ANF is predominant in ventricles and it is present at a thousand-fold lower concentration. The ten-fold discrepancy in the ratio of ANF mRNA to immunoreactivity between atria and ventricles could reflect a higher rate of peptide release in the latter. Thus, ventricular ANF production may be physiologically significant in view of the much larger ventricular mass.

Animals↗