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Tests, exploring hallmarks of cell-mediated immunity (CMI), were used in order to compare immunogenecity of same numbers of viable units from three different preparations of BCG vaccine derived from the same strain. Specific and... more
Tests, exploring hallmarks of cell-mediated immunity (CMI), were used in order to compare immunogenecity of same numbers of viable units from three different preparations of BCG vaccine derived from the same strain. Specific and non-specific cellular immune responses were assessed by several tests including, active and adoptive acquired resistance to Mycobacterium tuberculosis, local and systemic granuloma formation. BCG persistence in the spleen, delayed type hypersensibility (DTH) to tuberculin, immunopotentiation of DTH to sheep red blood cells, increase resistance to Listeria monocytogenes infection and occurrence of non-specific in vitro immunodepression. The ranking order of the three preparations concerning the active specific acquired resistance to tuberculosis did correlate well the ranking established for all immunopotency tests used in our study, however differences in acquired resistance were small as compared to differences observed for immunopotency tests. Moreover, adoptive transfer of same number of lymphoid cells from immune donors gave a different ranking order; the well dispersed fresh frozen (FF) vaccine being more able to induce higher adoptive protection as compared to the mechanically dispersed preparations. All these results clearly demonstrated that BCG could not be considered as single entity and that the test based on acquired resistance to M. tuberculosis or in vivo or in vitro hallmarks of CMI cannot be used as standard procedures.
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Human herpesvirus 8 (HHV-8) is thought to be possibly sexually transmitted in some populations, but few data are available on this mode of transmission. GOAL The goal was to study HHV-8 seroprevalence in patients attending a sexually... more
Human herpesvirus 8 (HHV-8) is thought to be possibly sexually transmitted in some populations, but few data are available on this mode of transmission. GOAL The goal was to study HHV-8 seroprevalence in patients attending a sexually transmitted disease (STD) clinic and to search for predictive factors of HHV-8 seropositivity. Five hundred twelve consecutive patients attending the STD clinic of Hôpital Saint-Louis (Paris) were tested for HHV-8 antibodies (immunofluorescence assay using two cell lines, BCP-1 and ISI n. butyrate [3 mmol/l]). A standardized questionnaire was used to obtain demographic, behavioral, and clinical data. Predictive factors of HHV-8 seropositivity were considered in univariate and multivariate analysis with use of logistic regression models. In testing of the patients for HHV-8 antibodies, 67/512 (13.1%) tested positive: 53/346 (15.3%) of men and 14/166 (8.4%) of women ( = 0.03). The predictive factors of HHV-8 seropositivity for men were the country of orig...
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Tuberculin skin testing (TST) and Interferon-gamma (IFNγ)release assays (IGRAs) are presently the only available assays for the detection of Mycobacterium tuberculosis infected individuals. IGRAs might progressively replace TST, as... more
Tuberculin skin testing (TST) and Interferon-gamma (IFNγ)release assays (IGRAs) are presently the only available assays for the detection of Mycobacterium tuberculosis infected individuals. IGRAs might progressively replace TST, as numerous published reports establish their higher specificity and similar sensitivity when tested in BCG vaccinated, immunocompetent individuals or in populations who may have been in contact with atypical mycobacteria. However, few published reports have commented on their role in TB diagnosis in immunocompromised individuals (HIV, immunosuppressive therapy, cancer...). It is the purpose of this report to review IGRAs published studies in HIV individuals in endemic and non endemic area for tuberculosis (TB). IGRAs were tested in the presence or absence of active TB but correlated to duration of exposure. In newly diagnosed active TB, IGRAs demonstrated a similar sensitivity to TST. In TB non infected individuals, TST and IGRAs also gave similar values wh...
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Delayed-type hypersensitivity (DTH) reactions induced with sheep red blood cells (1 X 10(8) SRBC/mouse) or with attenuated viable Mycobacterium bovis (4 X 10(6) BCG/mouse) inoculated subcutaneously and elicited, respectively, with SRBC or... more
Delayed-type hypersensitivity (DTH) reactions induced with sheep red blood cells (1 X 10(8) SRBC/mouse) or with attenuated viable Mycobacterium bovis (4 X 10(6) BCG/mouse) inoculated subcutaneously and elicited, respectively, with SRBC or protein-purified derivative (PPD), were studied regularly in separate groups of outbred mice and compared during a period of one year following immunization. The present report shows the existence of two distinct types of DTH reactions. The SRBC type consists of a reaction which peaks consistently at 18 h, reaches a maximum 4 days after immunization, and decreases progressively until the fourth month. This local reaction, mediated by specific committed T cells as demonstrated by adoptive transfer experiments, was shown to consist mainly of a polymorphonuclear leukocyte infiltration. The PPD type consists of a local reaction which presents a different time course, the peak shifting from 18 to 42 h during the first two months after immunization, and which persists unchanged over a year after immunization. This second type of DTH reaction consisted of an early phase of polymorphonuclear infiltration followed by an increased number of mononuclear cells. Evidence is also given that the differences in the expression of these two types of DTH reactions depended neither upon the physical characteristics of the two antigens used for elicitation nor upon the nonspecific environmental modulating activity of BCG, since soluble SRBC protein and heat-killed BCG cells elicited the same distinct types, and the two distinct DTH reaction types could be elicited in mice immunized with both BCG and SRBC.
Research Interests: Kinetics, Mice, Sheep, Female, Animals, and 4 moreTime Factors, Erythrocytes, Mycobacterium bovis, and Time Course
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A new scenario has been unraveled recently--the interaction between the human dendritic cell (DC) and Mycobacterium tuberculosis. Whether this encounter represents a defense mechanism by the invaded host, or a smoke screen, masking the... more
A new scenario has been unraveled recently--the interaction between the human dendritic cell (DC) and Mycobacterium tuberculosis. Whether this encounter represents a defense mechanism by the invaded host, or a smoke screen, masking the presence of an invader is still unknown. The intracellular behavior of M. tuberculosis inside DCs differs compared to macrophages (Mphis), with a failure of replication. The intracellular compartment of the DC, disconnected from the exocytic and endocytic pathways, and characterized by the absence of endoplasmic reticulum and Golgi features, places M. tuberculosis in a hostile environment, where a ready source of nutrients is scarce. The differential behavior inside Mphis and DCs is linked to a different portal of entry. DCs harbor surface lectins receptors, like DC-specific intercellular adhesion molecule-3 grabbing nonintegrin (DC-SIGN/CD209), a binding site which is absent on Mphis. This receptor interacts exclusively with M. tuberculosis. The ligand is the mannose-capped lipoarabinomanan (LAM), absent from atypical mycobacteria. M. smegmatis, M. chelonae and M. fortuitum, which possess LAM capped with phosphoinositides residues, do not bind to DC-SIGN, demonstrating a role for DC-SIGN as a 'pattern-recognition receptor' with the ability to differentiate between pathogenic and non-pathogenic mycobacteria. Interactions of M. tuberculosis with DC-SIGN have antiinflammatory effects. Whether this property is of benefit to the invader remains to be discovered.
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The susceptibility of Klebsiella oxytoca isolates was tested by an agar diffusion method (167 strains collected in six countries) and an agar dilution method (38 strains). Multivariate analysis of inhibition zone diameters by principal... more
The susceptibility of Klebsiella oxytoca isolates was tested by an agar diffusion method (167 strains collected in six countries) and an agar dilution method (38 strains). Multivariate analysis of inhibition zone diameters by principal component analysis clearly individualised four susceptibility patterns, including the phenotype of strains overproducing beta-lactamase and resistant to penicillins, first-generation cephalosporins, cefuroxime and aztreonam, but susceptible to ceftazidime. This phenotype was different from that conferred by plasmid-mediated extended-spectrum beta-lactamases; strains expressing these enzymes were also resistant to ceftazidime and cefotaxime. The bla(oxy) gene from K. oxytoca was introduced into Escherichia coli and K. oxytoca recipients and conferred increased resistance to beta-lactams in the recipient cells. Clavulanic acid was effective in association with piperacillin (MIC decreased 36-fold), ceftriaxone (35-fold) and aztreonam (19-fold) against overproducing strains, in spite of a relatively high IC50 (0.3 microM). Sulbactam (IC50, 400 microM) was ineffective in this context when combined with piperacillin (MIC decreased 1.5-fold), ceftriaxone (1.6-fold) and aztreonam (1.6-fold). The inhibitory activity of tazobactam (IC50, 8.2 microM) was heterogeneous depending on the strain and the beta-lactam with which it was combined. When combined with piperacillin or ceftriaxone little potentiation in antibiotic activity occurred (MIC decreased 3.9-fold and 4.5-fold, respectively); however, tazobactam plus aztreonam resulted in a 50-fold decrease in MIC of antibiotic.
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Cryptococcus neoformans is responsible for pulmonary and meningal infections in HIV patients. The lack of effective cellular cooperation caused by the low level of CD4+ cells, and the resistance of C. neoformans to phagocytosis allows... more
Cryptococcus neoformans is responsible for pulmonary and meningal infections in HIV patients. The lack of effective cellular cooperation caused by the low level of CD4+ cells, and the resistance of C. neoformans to phagocytosis allows growth and persistence of the yeast in the host. We describe here an in-vitro model of intracellular replication of C. neoformans inside J774-A.1 macrophages, and the determination of the intracellular antifungal activity of amphotericin B and fluconazole alone or in association with IFN-gamma. The maximum inhibitory effect was observed with one MIC of amphotericin B and 100 or 1000 IU/mL of IFN-gamma. amphotericin B alone (at 1 x MIC), or either 1 x or 50 x MIC of fluconazole in normal or IFN-gamma activated macrophages, did not eradicate the ingested yeast. A potential underlying mechanism of the synergy of amphotericin B in IFN-gamma primed macrophages was investigated by measurement of nitrite level and by use of the NO synthase competitive inhibitor, NG-monomethyl L-arginine (NMMA). One MIC of amphotericin B was able to activate the synthesis of nitrogen reactive intermediates in IFN gamma-primed macrophages. NMMA treated infected macrophages responded less well to IFN-gamma priming, resulting in a moderate inhibition in subsequent amphotericin B exposure.
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Groups of 10 mice were challenged with 10(4) trypomastigotes of the Y strain of Trypanosoma cruzi. Cyclophosphamide (200 mg per kg) was used for immunosuppression and administered two days before infection in one group and on day 5 after... more
Groups of 10 mice were challenged with 10(4) trypomastigotes of the Y strain of Trypanosoma cruzi. Cyclophosphamide (200 mg per kg) was used for immunosuppression and administered two days before infection in one group and on day 5 after infection in a second group. Enhancement of infection was more drastic in the second group, with a uniform acceleration of mortality and no clearance of the blood parasites. Electron microscopy showed that the hepatocytes were colonized by T. cruzi and that the invasion of the liver, spleen and lungs was associated with secondary infection by bacteria, which may be one of the cases of acceleration of mortality in infected mice. It was suggested that immunosuppressive therapy may favor unexpected symptoms and tissue localization of parasites in patients with Chagas' disease.
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Research Interests: Immunology, Cellular Immunology, Spleen, Mice, Female, and 3 moreAnimals, Species Specificity, and Interleukin
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Research Interests: Immune response, Flow Cytometry, Dendritic Cells, Tuberculosis, Humans, and 14 moreMycobacterium tuberculosis, Dendritic cell, The, Lung, Human immunodeficiency virus, Lipopolysaccharides, Monocytes, Time Factors, HeLa cells, Experimental Medicine, Lymph Node, Immunoglobulins, Mannose receptor, and Cell Adhesion Molecules
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Lactobacilli recovered from the blood, cerebrospinal fluid, respiratory tract, and gut of 20 hospitalized immunocompromised septic patients were analyzed. Biochemical carbohydrate fermentation and total soluble cell protein profiles were... more
Lactobacilli recovered from the blood, cerebrospinal fluid, respiratory tract, and gut of 20 hospitalized immunocompromised septic patients were analyzed. Biochemical carbohydrate fermentation and total soluble cell protein profiles were used to identify the species. Hydrogen peroxide production was measured. Susceptibility to 19 antibiotics was tested by a diffusion method, and the MICs of benzylpenicillin, amoxicillin, imipenem, erythromycin, vancomycin, gentamicin, and levofloxacin were determined. A small number of species produced H2O2, and antibiotic susceptibilities were species related. Eighteen (90%) of the isolates were L. rhamnosus, one was L. paracasei subsp. paracasei, and one was L. crispatus. L. rhamnosus, L. paracasei subsp. paracasei isolates, and the type strains were neither H2O2 producers nor vancomycin susceptible (MICs, >/=256 microgram/ml). L. crispatus, as well as most of the type strains of lactobacilli which belong to the L. acidophilus group, was an H2O...
Research Interests: Adolescent, Antibiotic Resistance, Clinical Microbiology, Biological Sciences, Phylogeny, and 17 moreCerebrospinal Fluid, Humans, Child, Female, Clinical, Lactobacillus, Male, Microbial genetic and drug resistance, Species identification, Fermentation, Hydrogen Peroxide, Middle Aged, Anti-Bacterial Agents, Adult, Immunocompromised host, Dietary Supplement, and Antibiotic Susceptibility
DHA-1, a plasmid-mediated cephalosporinase from a single clinical Salmonella enteritidis isolate, conferred resistance to oxyimino-cephalosporins (cefotaxime and ceftazidime) and cephamycins (cefoxitin and moxalactam), and this resistance... more
DHA-1, a plasmid-mediated cephalosporinase from a single clinical Salmonella enteritidis isolate, conferred resistance to oxyimino-cephalosporins (cefotaxime and ceftazidime) and cephamycins (cefoxitin and moxalactam), and this resistance was transferable to Escherichia coli HB101. An antagonism was observed between cefoxitin and aztreonam by the diffusion method. Transformation of the transconjugant E. coli strain with plasmid pNH5 carrying the ampD gene (whose product decreases the level of expression of ampC) resulted in an eightfold decrease in the MIC of cefoxitin. A clone with the same AmpC susceptibility pattern with antagonism was obtained, clone E. coli JM101(pSAL2-ind), and its nucleotide sequence was determined. It contained an open reading frame with 98. 7% DNA sequence identity with the ampC gene of Morganella morganii. DNA sequence analysis also identified a gene upstream of ampC whose sequence was 97% identical to the partial sequence of the ampR gene (435 bp) from M....
Research Interests: Microbiology, Medical Microbiology, Gene expression, Phylogeny, In Vitro, and 15 moreSalmonella enteritidis, Escherichia coli, Resistance, Bacteria, Microbial genetic and drug resistance, Plasmids, Enzyme, Molecular cloning, Antimicrobial agents, Amino Acid Sequence, Base Sequence, Open Reading Frame, Plasmid, Beta Lactamases, and DNA sequence
Klebsiella oxytoca 1731, which showed a wide spectrum of resistance to beta-lactams, including cefoxitin, was isolated in 1994 from a patient in Genoa, Italy. This strain contained a plasmid-mediated AmpC beta-lactamase with a pI of 7.25.... more
Klebsiella oxytoca 1731, which showed a wide spectrum of resistance to beta-lactams, including cefoxitin, was isolated in 1994 from a patient in Genoa, Italy. This strain contained a plasmid-mediated AmpC beta-lactamase with a pI of 7.25. Sequencing of the corresponding DNA of K. oxytoca 1731 revealed 96 and 97% identities of the deduced amino acid sequence with FOX-1 and FOX-2, respectively.
Research Interests: Microbiology, Medical Microbiology, Antibiotic Resistance, Italy, Humans, and 20 moreSequence alignment, Escherichia coli, Female, Klebsiella, Plasmids, Enzyme, Intensive Care Unit, Spectrum, Gram-negative bacteria, Molecular Characterization, Group, Antimicrobial agents, Beta Lactams, Microbial Sensitivity Tests, Extraction Method, Amino Acid Sequence, Antibiotic Susceptibility, Plasmid DNA, Beta Lactamases, and Klebsiella pneumoniae
To assess the value of routine transesophageal echocardiography (TEE) in diagnosing traumatic disruption of the aorta (TDA) in trauma patients presenting without enlarged mediastinum on chest x-ray films. Prospective study. TEE was... more
To assess the value of routine transesophageal echocardiography (TEE) in diagnosing traumatic disruption of the aorta (TDA) in trauma patients presenting without enlarged mediastinum on chest x-ray films. Prospective study. TEE was routinely performed to exclude the presence of TDA in patients who sustained severe trauma secondary to abrupt deceleration collisions and presented with an upper mediastinum of fewer than 8 cm on supine chest x-ray films. Patients were divided into two groups according to the presence (group I) or absence (group II) of mediastinal hematoma diagnosed during TEE examination. Radiographic signs regarded as indicators of the presence of TDA were evaluated in both groups. Among the 40 consecutive patients studied, TEE demonstrated two cases of TDA associated with a mediastinal hematoma that were confirmed by both aortography and surgery. One of the patients had a normal mediastinum on presentation chest x-ray films, and the other only exhibited a blurred aort...
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Thechromosomallyencoded b-lactamasegene(blaOXY-2)ofthewild-typeKlebsiellaoxytocaSL911wascloned and sequenced. Its nucleotide sequence similarity with the previously sequencedK. oxytoca b-lactamase gene (blaOXY-1) (Y. Arakawa, M. Ohta, N.... more
Thechromosomallyencoded b-lactamasegene(blaOXY-2)ofthewild-typeKlebsiellaoxytocaSL911wascloned and sequenced. Its nucleotide sequence similarity with the previously sequencedK. oxytoca b-lactamase gene (blaOXY-1) (Y. Arakawa, M. Ohta, N. Kido, M. Mori, H. Ito, T. Komatsu, Y. Fujii, and N. Kato, Antimicrob. Agents Chemother. 33:63-70, 1989) is 87.3%, and its amino acid similarity is 89.7%. This group ofK. oxytoca b-lactamases is related to chromosomal b-lactamases of Citrobacter diversus, Proteus vulgaris, and Yersinia enterocolitica and to the plasmid-mediated extended-spectrum b-lactamases MEN-1 and Toho-1. By colony hybridization with 86 strains susceptible and resistant to aztreonam, isolated in six countries, K. oxytoca b-lactamasegeneshybridizedwitheitheraspecificblaOXY-1DNAprobe(668bp)orablaOXY-2DNAprobe(723 bp).Thus, b-lactamasegenescouldbedividedintotwogroups:blaOXY-1(47%ofthestrains)andblaOXY-2(53% of the strains). A study of isoelectric points confirmed the great variabili...
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Atrial natriuretic factor (ANF) release is augmented by atrial distention whereas positive end-expiratory pressure (PEEP) ventilation has the opposite effect. We tested the hypothesis that PEEP-induced decrease in ANF secretion is... more
Atrial natriuretic factor (ANF) release is augmented by atrial distention whereas positive end-expiratory pressure (PEEP) ventilation has the opposite effect. We tested the hypothesis that PEEP-induced decrease in ANF secretion is mediated by a decrease in right atrial (RA) ...