Mediastinal aspergilloma ten years after thoracic surgery.
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Biomedical subjects
Publications and source records attributed to J Raymond.
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BACKGROUND: Mycoplasma pneumoniae is a frequent but underdiagnosed cause of community-acquired pneumonia (CAP) in children, and appropriate macrolide treatment is often given late. The aim of this work was to estimate the frequency of pulmonary involvement in children 6 months after a clinical episode of Mycoplasma CAP. METHODS: We measured carbon monoxide diffusion capacity (TLCO) and conducted spirometric tests in 35 children without asthma or chronic lung disease (ages 4.5 to 15 years), 6 months and 1 year after acute CAP caused by M. pneumoniae (23 children), pneumococci (5 children) or viruses (7 children). Only 11 of 23 patients with M. pneumoniae CAP required hospitalization, whereas all the patients with pneumococcal or viral pneumonia were admitted to hospital. RESULTS: Lung volumes and spirometric tests were normal for all children. TLCO was normal 6 months after pneumococcal or viral pneumonia (87 to 112% of expected values for height and sex). After acute M. pneumoniae CAP, 11 of 23 patients (48%) had TLCO values <80% of the expected value. The extent of change in lung diffusion capacity was correlated with the delay to diagnosis and treatment: TLCO was low in 8 of 11 patients given macrolide treatment 10 days or more after the onset of acute symptoms vs. only 3 of 10 patients given appropriate treatment in the first 10 days. TLCO was low in 7 of 7 who received macrolide therapy for <2 weeks. TLCO had increased slightly after 1 year in the 5 patients retested after a new course of macrolide treatment. TLCO reached the lower normal range in 2 patients controlled after 3 years. CONCLUSIONS: The abnormal TLCO values suggest that some children with Mycoplasma pneumonia have reduced pulmonary gas diffusion after recovery from the illness. The reduction is related to delay and short macrolide therapy.
This study investigated control of heart rate (HR) and mean arterial pressure (MAP) at rest and during electrical stimulation (ES) leg cycling exercise (LCE) in paraplegics (Para). Seven men with complete spinal lesions (T(5)-T(11)) and six able-bodied (AB) men participated in this study. Beat-to-beat changes in HR and MAP were recorded during carotid sinus perturbation. Carotid baroreflex function curves were derived at rest and during ES-LCE for Para and during voluntary cycling (Vol) for AB. From rest to ES-LCE, oxygen uptake (VO(2)) increased (by 0.43 l/min) and HR rose (by 11 beats/min), yet MAP remained unchanged. In AB, Vol increased VO(2) (by 0.53 l/min), HR (by 22 beats/min), and MAP (by 8 mmHg). ES-LCE did not alter the carotid sinus pressure (CSP)-MAP relationship, but it displaced the CSP-HR relationship upward relative to rest. No rightward shift was observed during ES-LCE. Vol by AB produced an upward and rightward displacement of the CSP-MAP and CSP-HR relationships relative to rest. These findings suggested that the carotid sinus baroreflex was not reset during ES-LCE in Para.
BACKGROUND AND PURPOSE: Growth factors (GFs) may favor the healing of aneurysms treated with endovascular techniques by stimulating neointima formation. METHODS: Bilateral carotid aneurysms were constructed with venous pouches in 50 pigs and embolized intraoperatively with collagen sponges with and without GFs (platelet-derived growth factor-BB [PDGF-BB] 0.15 or 1.5 microg or transforming growth factor-beta(1) [TGF-beta(1)] 60 or 600 ng) in each animal. DNA synthesis, cell proliferation, and collagen secretion assays were performed to assess the in vitro effects of GFs on neointimal cells harvested from the treated aneurysms. (125)I-PDGF-BB was used to study in vivo GF release from sponges. The thickness of the neointima at the surface of the sponges was measured 2 weeks after surgery. Since porcine aneurysms tend to heal after collagen sponge embolization, this experiment was repeated in dogs, which have shown a propensity for recurrence with the same technique, with 600 ng TGF-beta(1) or platelet extracts. RESULTS: PDGF-BB stimulated DNA synthesis and cell proliferation, while TGF-beta(1) strongly increased collagen synthesis of neointimal cells in vitro. Clearance of (125)I-PDGF-BB from the sponges followed a biphasic curve, with 1.5% of exogenous PDGF-BB remaining at 1 week. The local delivery of PDGF-BB (0.15 or 1.5 microg) and TGF-beta(1) (600 ng) significantly increased neointimal thickness at the neck of porcine aneurysms, while 60 ng of TGF-beta(1) had no demonstrable effect. TGF-beta(1) (600 ng) or platelet extracts had no influence on canine aneurysms. CONCLUSIONS: PDGF-BB and TGF-beta(1) can stimulate neointimal cells in vitro and neointima formation in vivo, but TGF-beta(1) and platelet extracts do not compensate for deficient thrombosis in canine aneurysms. Effects on the long-term results of embolization remain speculative.
Oestrogens protect against ischaemic heart disease in the post-menopausal female by increasing serum concentrations of apolipoprotein (apo) AI and the abundance of high-density lipoprotein particles. In men and experimental male animals, the administration of oestrogen has variable effects on apo AI expression. As the major mode of oestrogen action on target genes involves regulating promoter activity and hence transcription, oestrogen is expected to alter transcription of the apo AI gene. To test this hypothesis, the effect of 17beta-oestradiol (E(2)), on rat apo AI promoter activity in male hepatoma HuH-7 cells, was tested by co-transfecting a reporter template, pAI.474.CAT containing-474 to-7 of the rat apo AI promoter and an oestrogen receptor (ER) expression vector, pCMV-ER. Transfected cells exposed to E(2) showed a dose-dependent decrease in chloramphenicol acetyltransferase (CAT)-activity, with a maximum 91+/-1.5% reduction at 1 microM E(2). Deletional analysis of the promoter localized the inhibitory effect of ER and E(2) to site B (-170 to-144) with an adjacent 5' contiguous motif, site S (-186 to-171) acting as an amplifier. HuH-7 cell nuclear extracts showed binding activities with both sites S and B, but recombinant human ER did not. Furthermore, nuclear extracts from E(2)-treated HuH-7 cells showed weaker binding activity to site B, but not to site S. In summary, the inhibitory effect of ER and E(2) on rat apo AI gene activity is mediated by a promoter element, site B. This inhibitory effect arises from a mechanism that does not involve direct ER binding to the B-element. The conclusion that E(2) inhibits apo AI transcription was confirmed in vivo. Treatment of male adult Sprague-Dawley rats with up to 200 microg E(2) for 7 days decreased apo AI protein and hepatic mRNA by 72+/-21% and 68+/-1.4% respectively. Results of 'run-on' transcription of the apo AI gene in isolated hepatic nuclei showed a 55% decrease in hormone-treated male rats. These findings suggest that E(2) exerts primarily an inhibitory effect within male hepatic nuclei.
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The overall incidence of nosocomial infections (NI) in pediatrics ranges between 2.3% to 12.6%. They have great variations according to age (7-12% under 1 year of age vs 1.5-4% after ten years of age), and the nature of the unit (3-26% in intensive care units vs 1-4% in general pediatrics). The main sites of infection are in children gastrointestinal infections (10-35% of NI) and bacteremia (10-23% of NI) whereas in adults urinary tract infections (31.7 to 35%) and respiratory infections (19 to 25%) are the most frequent. Viruses represent 22-27% of the isolated pathogens, and Gram positive cocci 31-50% (half of them are coagulase negative staphylococci). The most frequent Gram negative bacilli are Pseudomonas aeruginosa (9-15%), E. coli (6-16%) and Klebsiella pneumoniae (3-5%). Candida represent 3% of isolated pathogens in NI. The proportion of methicilline-resistant Staphylococcus aureus is lower in children than in adults. The prevalence of methicillin resistance of CNS is however close to that observed in adults, as is the multiresistance of Gram negative bacilli (Klebsiella). Candida infections seem an emerging problem in paediatrics. These results underline the necessity to limit the antimicrobial therapy in children as in adults.
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The aim of this study was to investigate the potential plasticity of the vestibular system, in structural and biochemical terms, at the level of the gravity receptors (the sensory hair cells), the primary neurons relaying the sensory signals (the vestibular ganglion neurons) and their projections into the vestibular nuclei. We studied the biochemical differentiation of the sensory cells and of the vestibular ganglion by investigating which calcium-binding proteins were present. We studied the development of peripheral synaptic connections of the efferent system by investigating the distribution of CGRP (calcitonin-gene related-peptide) and we also studied the cerebellar synaptic connections in the vestibular nuclei, as identified by the presence of calbindin. Putative changes were studied after a 17-day episode of microgravity (Neurolab STS-90), in developing rats between postnatal days 8 and 25. The extent to which these changes could be caused by alterations in gravity was determined by examining sensory and nervous structures not involved in gravity detection, the cochlea and the cochlear nuclei.
PURPOSE: To determine whether the addition of opioids alters the density and spread of intrathecal local anesthetics in vitro. METHODS: In Part I, the densities of hyperbaric bupivacaine 0.75% (HB), hyperbaric lidocaine 5% (HL) and isobaric bupivacaine 0.5% (IB) with and without morphine (M), and fentanyl (F) were measured at 22 degrees C. In Part II a model was constructed utilizing a column containing a solution similar in composition to cerebrospinal fluid (CSF) at 37 degrees C. The various local anesthetic-opioid solutions, coloured with crystalline methylene blue dye, were injected at 22 degrees C into the column at a controlled rate through a spinal needle. The direction and extent of spread of the injectates were compared. RESULTS: The relative densities of the five solutions were: HB = HL > IB > M > F. The addition of fentanyl to IB reduced the density of the final solution (P < 0.05). In the model, IB alone and IB with morphine showed mainly downward spread, with the addition of fentanyl to IB resulting in upward movement (P = 0.004). The hyperbaric local anesthetics moved downward with or without opioids. CONCLUSION: The addition of fentanyl reduces the density of IB in vitro and alters its movement in simulated CSF. This may prove to be important in predicting the level of spinal block in clinical practice.
The purpose of this study was to investigate the cardiovascular and haemodynamic responses that occur during moderate orthostatic challenge in people with paraplegia, and the effect of electrical stimulation (ES)-induced leg muscle contractions on their responses to orthostatic challenge. Eight males with complete spinal lesions between the 5th and 12th thoracic vertebrae (PARA) and eight able-bodied individuals (AB) volunteered for this study. Changes in heart rate (fc), stroke volume (SV), cardiac output (Qc), mean arterial pressure (MAP), total peripheral resistance (TPR), limb volumes and indices of neural modulation of fc, [parasympathetic (PNS) and sympathetic (SNS) nervous system indicators] were assessed during: (1) supine rest (REST), (2) REST with lower-body negative pressure at -30 torr (LBNP -30, where 1 torr = 133.32 N/m2), and (3) for PARA only, LBNP -30 with ES-induced leg muscle contractions (LBNP + ES). LBNP -30 elicited a decrease in SV (by 23% and 22%), Qc (by 15% and 18%) and the PNS indicator, but an increase in fc (by 10% and 9%), TPR (by 23% and 17%) and calf volume (by 1.51% and 4.04%) in both PARA and AB subjects, respectively. The SNS indicator was increased in the AB group only. Compared to LBNP -30, LBNP + ES increased SV (by 20%) and Qc (by 16%), and decreased TPR (by 12%) in the PARA group. MAP was unchanged from REST during all trials, for both groups. The orthostatic challenge induced by LBNP -30 elicited similar cardiovascular adaptations in PARA and AB subjects. ES-induced muscle contractions during LBNP -30 augmented the cardiovascular responses exhibited by the PARA group, probably via reactivation of the skeletal muscle pump and improved venous return.
A new semiquantitative enzyme immunoassay (Platelia Helicobacter pylori; Sanofi Diagnostics Pasteur, France) was evaluated and compared with two other serological assays (Gap-test IgG; Bio-Rad, France; and Cobas Core; Roche, Switzerland) for the diagnosis of Helicobacter pylori infection in children. The three tests were compared with the examination of biopsy samples obtained from 160 dyspeptic subjects (mean age, 9 +/- 4.7 years). Discrepant results were studied using an immunoblot technique. The response obtained for the Platelia assay in children was significantly lower than that obtained in a previously described population of 92 adults (Helicobacter pylori-negative mean ratios, 0.376 vs. 0.504, P<0.000783; Helicobacter pylori-positive mean ratios, 1.95 vs. 2.67, P<0.000003). Thus, the optimal cut-off for children (0.80) was lower than the one recommended for adults (1.10). According to the Receiver Operating Characteristic (ROC) curve analysis and to the Wilcoxon value, the Platelia and Cobas Core assays showed the highest discriminatory properties (Wilcoxon value, 0.94 for both) compared with the Gap-test IgG (Wilcoxon value, 0.91). When the newly established cut-off value (0.80) was used, the performance of Platelia was equivalent to that of Cobas Core (sensitivity: 94.4% for each; respective specificities, 86.8% and 90.6%). The Gap-test IgG had a lower sensitivity (maximum, 79%) and a higher specificity (maximum, 95.3%), but there were difficulties in interpretation because its grey zone encompassed 12% of the sera. In conclusion, the results showed good performance of the Platelia Helicobacter pylori assay and confirmed the merit of a specific cut-off value for use of this test in children.
PATIENTS AND METHODS: In a pediatric hospital of Paris, from 1993 to 1998, respiratory secretions were positive for respiratory syncytial virus (RSV) in 26.3% of 4,738 children (0-5 years) examined or hospitalized for lower respiratory tract infections. Rotavirus detection was positive in stools of 23.7% of the 8,537 children of the same age with acute diarrhea. RESULTS: The RSV epidemic peak occurred annually in Paris in December and the rotavirus outbreak peaks were observed in December/January. The winter seasonal peaks remained constant for both pathogens and the temporal appearance of these peaks was constant from 1993 to 1998. Fifty to sixty-one percent of rotavirus and 77 to 92% of RSV infections were observed in November, December or January. These simultaneous outbreaks provoked important problems in hospital organization and prevention of nosocomial infections. CONCLUSION: The coincidence of RSV and rotavirus peaks is not found in all countries. The epidemic patterns have to be checked in other parts of France and Europe because this could be important when active immunization programs will be available for these two pathogens.
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The 20S proteasome is the catalytic core of the ubiquitin proteolytic pathway, which is implicated in many cellular processes. The cylindrical structure of this complex consists of four stacked rings of seven subunits each. The central cavity is formed by two beta catalytic subunit rings in which protein substrates are progressively degraded. The 20S proteasome is isolated in a latent form which can be activated in vitro by various chemical and physical treatments. In this study, the effects of high hydrostatic pressures on 20S proteasome enzymatic activity were investigated. When proteasomes were subjected to increasing hydrostatic pressures, a progressive loss of peptidase activities was observed between 75 and 150 MPa. The inactivation also occurred when proteasomes were pressurized in the presence of synthetic peptide substrates; this may be the result of the dissociation of the 20S particle into its subunits under pressure, as was shown by PAGE. Pressurized proteasomes also lost their caseinolytic activity. In contrast, in the presence of casein, the pressure-induced inactivation and the dissociation of the 20S particles were prevented. In addition, in comparison to that observed at atmospheric pressure, their caseinolytic activity was increased under pressure. Following depressurization, the caseinolytic activity returned to basal levels but was further enhanced following an additional pressurization treatment. Thus, the structure of the 20S particle exhibits a certain degree of plasticity. This pressure-induced activation of the 20S proteasome is discussed in relation to its hollow structure, its currently accepted proteolytic mechanism and the general effect of high pressures on the biochemical reactions and structures of biopolymers.
The aim of the study was to identify serum markers able to differentiate bacterial and viral origin in acute diarrhoea. Interferon-alpha (INF-alpha), C-reactive protein (CRP) and interleukin-6 were determined on admission in the sera of 119 children aged between 1 mo and 14 y who were hospitalized for rotavirus (n = 60) or bacterial diarrhoea (Salmonella spp. 39 cases, Shigella spp. 15 cases, Campylobacter jejuni 5 cases). CRP concentration was >10 mg/l in 48.3% of children with viral gastroenteritis and 86.4% of children with bacterial gastroenteritis. IL6 concentration was >100 pg/ml in 11.7% and 26.3% of cases, respectively. INF-alpha was detected in 79.1% of children with rotavirus (sens 79%) and in 3.5% (spec 93%) with bacterial gastroenteritis. However the INF-alpha assay takes 48 h and pathogens are often identified from stools before interferon results are available. We found that serum markers are not discriminating enough to differentiate between viral and bacterial gastroenteritis in emergency cases.
At the early stages of myogenesis, myoblasts fuse to form multinucleated myotubes. This morphological differentiation is the result of dynamic changes in gene regulation and expression. The ubiquitin proteasome-dependent pathway has been reported to play an important role in many aspects of cellular functions such as regulation of growth and cell cycle progression. In this study, we showed that the amount of mRNA's corresponding to the iota subunit of the 20S proteasome, the level of the S4 subunit of the 19S complex and the 20S and 26S proteasomes peptidase activities increased during myoblast fusion. Cell permeable 20S proteasome inhibitor prevented fusion with concomitant accumulation of ubiquitin-conjugated protein. On the other hand, inhibition of ubiquitin ligase E3 enzymes prevented the formation of ubiquitin conjugate and decreased the fusion process. These results strongly support the involvement of the ubiquitin-proteasome proteolytic pathway in the events leading to myoblast fusion.