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J L Gaillard

Publications and source records attributed to J L Gaillard.

At least 55 records · Page 3Linked to original sources
PubMed1997

Two-dimensional 1H-NMR and CD structural analysis in a micellar medium of a bovine alphaS1-casein fragment having benzodiazepine-like properties.

The conformation of the benzodiazepine-like decapeptide, YLGYLEQLLR, corresponding to residues 91-100 of bovine alphaS1-casein, has been examined in SDS micelles using CD, two-dimensional 1H-NMR and restrained molecular-dynamics simulation. Evidence is presented that the decapeptide adopts a rigid structure in water/SDS micellar medium, but not in water or dimethylsulfoxide. The three-dimensional structure, consistent with the proton-proton distances obtained from the quantitative analysis of the two-dimensional NOEs, was generated by restrained energy minimization and molecular-dynamics simulation. In water/SDS micellar medium, YLGYLEQLLR adopts an amphipathic helicoid structure with distinct hydrophobic and hydrophilic faces. The relative disposition of the tyrosine aromatic rings was compared with that of the aromatic rings in the benzodiazepines.

Animals↗
PubMed1997

Full monosomy 21, prenatally diagnosed by fluorescent in situ hybridization.

We describe a case of full monosomy 21 which was prenatally diagnosed in chorionic villi by fluorescent in situ hybridization (FISH). Because of intrauterine fetal death, a curettage was performed and cytogenetic analysis of skin fibroblasts confirmed the presence of monosomy 21 in fetal cells. DNA investigations showed a paternal origin of the single chromosome 21. Inspection and autopsy of the fetus revealed several congenital malformations. Some of them have been reported in earlier studies of monosomy 21; others concern new observations. Regarding the eye, the following abnormalities were microscopically observed: absence of the anterior and posterior eye chambers, aniridy, a hypoplastic ciliary body, Peter's anomaly, and a double retina with secondary dysplasia. In addition, malformations of the extremities were seen: partial, proximal syndactyly of digits 3 and 4 of the right hand; pes varus position of the right foot; and transverse reduction defect at the tarsals of the left foot. To our knowledge, this is the first case in which full monosomy 21 has been proven.

Abnormalities, Multiple↗
PubMed1997

Nosocomial outbreak of Clostridium difficile diarrhea in a pediatric service.

An outbreak of nosocomial diarrhea that occurred in a pediatric orthopedic service between 1 December 1993 and 15 April 1994 is reported. A total of 37 patients (mean age, 9.6 years; range, 2 months-19.3 years) were involved in the outbreak, including six patients with bacteriologically documented Clostridium difficile infection. A multivariate analysis identified lincomycin treatment for at least three days as the only significant risk factor. Stool samples from four asymptomatic patients were also positive for Clostridium difficile and its cytotoxins. Isolates from all patients belonged to serogroup C, were highly resistant to lincomycin, and exhibited the same restriction pattern by pulsed-field gel electrophoresis. The outbreak ended after treatment with lincomycin was discontinued and hygiene control measures were implemented.

Adolescent↗
PubMed1997

Purification and characterization of equine testicular cytochrome P-450 aromatase: comparison with the human enzyme.

Cytochrome P-450 aromatase was purified by five chromatographic steps from adult stallion testis. It was first separated from NADPH-cytochrome P-450 reductase (reductase) on omega-aminohexyl-Sepharose 4B then purified to homogeneity on concanavalin A-Sepharose 4B, hydroxyapatite-Sepharose 4B, DEAE-Sepharose CL-6B and on a second hydroxyapatite-Sepharose 4B. On the other hand, purifications of the equine testicular and rat liver reductases, which allowed the reconstitution of aromatase activity in vitro, were achieved for each species in one chromatographic step on an adenosine 2',5'-diphosphate-agarose affinity column. Analysis on SDS/PAGE indicated single bands with apparent molecular masses of 53, 82, and 80 kDa for purified equine testicular cytochrome P-450 aromatase (eAROM), equine testicular reductase and rat liver reductase respectively. eAROM shows a time- and concentration-dependent activity that was stable for at least 2 months when stored at -78 degrees C. It is a highly hydrophobic protein composed from 505 residues and direct sequencing of its N-terminal part showed good homology when compared with human aromatase. When deglycosylated by N-glycosidase-F the apparent molecular mass of eAROM was decreased from 53 to 51 kDa as revealed by electrophoresis, its activity, however, was not impaired. eAROM exhibits much higher affinity for androgens than for 19-norandrogens, Km values were approximately 3, 16 and 170 nM for androstenedione (A), testosterone (T) and 19-nortestosterone (19-NT) respectively. However, it aromatizes 19-norandrostenedione (19-NA) slightly more efficiently than A, the estrone (E1) formed was 4.27 vs 3.54 pmol min-1 micrograms-1 respectively (P < 0.01). After incubation of eAROM with radiolabelled A and separation of steroids on HPLC, E1, 19-hydroxyandrostenedione (19-OHA) and 19-oxoandrostenedione (19-oxoA) were accumulated in the incubation medium in a time-dependent manner. The presence of 4-hydroxyandrostenedione (4-OHA), a suicide inhibitor of aromatase, cause a time-dependent inactivation of the enzyme. Whereas the activity of eAROM was unchanged in the presence of K+ (up to 250 mM), it was increased in the presence of EDTA (up to 50 mM) and decreased in the presence of DTT or Mg2+ (from 25 mM). We conclude that: (a) eAROM is a glycoprotein, however, deglycosylation by N-glycosidase-F does not appear to impair its activity, (b) eAROM aromatizes really both androgens and 19-norandrogens having a higher affinity for androgens, (c) the intermediary compounds of aromatization 19-OHA and 19-oxoA appear to be synthesized by the same active site that synthesizes E1 as the final product, (d) the inhibition of eAROM by increasing concentrations of Mg2+ and the stimulation of its activity by EDTA, taken together, indicate the importance of negatively charged residues in the polypeptide chain of equine aromatase, which play a role in enzymatic activity.

Amino Acid Sequence↗
PubMed1997

Histopathology and microbiology of isolated rectal bleeding in neonates: the so-called 'ecchymotic colitis'.

Rectal bleeding in neonates is an alarming event which suggests a possible necrotizing enterocolitis (NEC) but is usually the only symptom of an unexplained colitis characterized endoscopically by ecchymotic mucosal lesions, the so-called 'ecchymotic colitis' (EC). We studied histologically and bacteriologically 18 infants (mean age: 18 days) presenting with rectal bleeding by systematic rectosigmoidoscopy and intestinal biopsies. The 18 infants were hospitalized. Prematurity was found in seven cases and an underlying condition in 14 cases (respiratory distress: six cases; infection: six cases; surgery: two cases). Histology showed a mild to moderate inflammation (10/12) of the mucosa with a prevalence of polymorphonuclear cells (8/10), frequent focal haemorrhages (11/12) and foci of pneumatosis (4/12). Numerous bacteria were seen in the mucus layer focally forming large clusters. Cultures of intestinal biopsies yielded exclusively Enterobacteriaceae species: Escherichia coli (seven cases), Klebsiella spp. (seven cases), and Enterobacter cloacae (three cases); four cases were sterile. Our study demonstrates that neonatal bleeding is associated with endoscopic and histological 'ecchymotic colitis' lesions and with a peculiar microbial flora of EBC strains. EC and necrotizing enterocolitis share similar features raising the question of the link between the two syndromes.

Biopsy↗
PubMed1997

Fatal disseminated Mycobacterium smegmatis infection in a child with inherited interferon gamma receptor deficiency.

Mycobacterium smegmatis is a common environmental mycobacterium that was first identified in 1884, yet is a rare pathogen in humans. The few M. smegmatis infections reported to date have been localized and have occurred in association with a primary lesion in otherwise immunocompetent individuals. To our knowledge, no case of disseminated M. smegmatis infection has ever been reported, even in patients with severe immune deficiencies. We report a case of disseminated mycobacterial infection that was diagnosed in a 3-year-old girl. The pathogen was not identified as M. smegmatis until the patient was 6 years old. Her condition gradually worsened, and she died when she was 8 years old despite appropriate antimycobacterial therapy. No other opportunistic infections were documented. Immunological investigations revealed an inherited interferon gamma receptor 1 deficiency. This report identifies M. smegmatis as a new opportunistic agent that may be responsible for disseminated disease in immunocompromised individuals.

Bacteremia↗
PubMed1997

In vitro susceptibilities to amphotericin B, itraconazole, and miconazole of filamentous fungi isolated from patients with cystic fibrosis.

The antimicrobial activities of amphotericin B, itraconazole, and miconazole against 101 filamentous fungi from patients with cystic fibrosis were tested by a reproducible microdilution method. Itraconazole was very active against Aspergillus species and Scedosporium species (MIC at which 90% of the isolates were inhibited [MIC90], 0.06 to 0.5 mg/liter), whereas amphotericin B was less effective (MIC90, 0.5 to 8 mg/liter).

Amphotericin B↗
PubMed1997

Western blot analysis of antibody response to pneumococcal protein antigens in a murine model of pneumonia.

To detect new antigen candidates for serological tests, we studied the antibody response to pneumococcal protein antigens in mice infected intratracheally with various Streptococcus pneumoniae strains. Sera were tested by Western blotting against whole-cell protein extracts. Mice developed a detectable immunoglobulin G-type response against a small number of polypeptides. The antibody response was strain dependent: sera from individuals infected with the same strain gave similar banding patterns on immunoblots. The banding patterns varied with the strain used for infection. However, a band at 36 to 38 kDa was recognized by all reactive sera. This band appeared to correspond to a polypeptide that was antigenically well conserved among the different S. pneumoniae serotypes. An antibody response to this antigen developed in mice irrespective of the capsular type, the virulence, and the susceptibility to penicillin G of the infecting strain. Thus, this 36- to 38-kDa protein antigen may be of value for the development of a serological test for humans.

Animals↗
PubMed1997

Abnormal expression of pulmonary bombesin-like peptide immunostaining cells in infants with congenital diaphragmatic hernia.

Infants with congenital diaphragmatic hernia (CDH) have a high neonatal mortality and morbidity owing to lung hypoplasia and persistent pulmonary hypertension. Pulmonary neuroendocrine cells produce bombesin-like peptide (BLP), a peptide with growth factor-like properties involved in lung development. We examined the expression of BLP immunostaining in pulmonary neuroendocrine cells (PNEC), and in clusters of these cells called neuroepithelial bodies (NEB), in the lungs of three groups of infants: patients with CDH, newborns with lung hypoplasia due to other causes, and control subjects without lung abnormalities. Morphometric analysis included: 1) percent immunostained airways; 2) percent immunostained epithelium (i.e. frequency of PNEC and NEB); and 3) NEB size. Controls and infants with lung hypoplasia did not differ with respect to BLP immunostaining. The ipsilateral and the contralateral lungs in CDH had a similar BLP immunostaining pattern of PNEC and NEB. The BLP immunostaining varied between CDH cases, possibly due to the differences in clinical presentation. The mean NEB size was significantly increased in infants with CDH compared with the other two groups (p = 0.02). Some CDH cases with large NEBs also showed a high percentage of immunostained epithelium. Lung-body weight ratio correlated positively with percent immunostained airways, and negatively with the NEB size. We conclude that in lungs of CDH patients BLP immunostaining in PNEC and NEB differs from that of infants with lung hypoplasia due to other causes and controls. The increased BLP immunostaining observed in some cases of CDH might reflect a compensatory mechanism related to impaired lung development and/or failure of neuropeptide secretion during neonatal adaptation.

Bombesin↗
PubMed1996

The inlAB locus mediates the entry of Listeria monocytogenes into hepatocytes in vivo.

The intracellular parasite Listeria monocytogenes is able to induce its internalization by cultured mammalian cells that are not normally phagocytic. This process requires the expression of the chromosomal locus inlAB. We studied the virulence of an inlAB mutant and of its parent in murine listeriosis. Irrespective of the route of inoculation, the inlAB mutant was severely attenuated for growth in the liver. The livers of mice inoculated with the inlAB mutant displayed much smaller infectious foci than the parent as early as 24 h after infection. Electron microscopy showed that these foci consisted of a few inflammatory cells, with few bacteria; bacteria were rarely found within hepatocytes. In contrast, foci in livers of mice inoculated with the parent consisted of islets of heavily infected hepatocytes that were infiltrated by numerous neutrophils; bacteria seemed intact within hepatocytes and damaged within neutrophils. A direct role of inlAB for the entry of L. monocytogenes into hepatocytes was confirmed in a cell infection system using the murine embryonic hepatocyte cell line TIB73. The inlAB mutant was approximately 20-fold less invasive in trans. The "invasion locus" inlAB contributes to protect L. monocytogenes from the host's innate defense mechanisms by promoting its entry into hepatocytes.

Administration, Oral↗
PubMed1996

Chorionic villus sampling and materno-fetal transfusions: an immunological pathogenesis of vascular disruptive syndromes?

Experimental materno-embryonic transfusions with serum that is immunologically active against blood group antigens cause congenital malformations in the rat embryo. In view of the possible increased incidence of vascular disruptive syndromes after chorionic villus sampling (CVS), we investigated the occurrence of materno-fetal transfusions (MFTs) in this procedure. In 18 pregnant women experiencing two needle introductions at CVS, we looked immunohistochemically at the presence of haemoglobin A1-containing maternal erythrocytes in the fetal circulation of the separately collected first and second chorionic villus samples. In 4 of 18 patients (22 per cent), a significant increase of maternal cells was observed in the second sample compared with the first sample, indicating the occurrence of MFT by CVS. On the rare occasion of maternal immunization against fetal antigens, a CVS-associated MFT might provoke immunological damage to the fetus.

Antigen-Antibody Reactions↗
PubMed1996

[Pneumococcal meningitis in children: should probabilistic antibiotherapy of infectious meningitis be modified?].

BACKGROUND: Since a significant proportion of Streptococcus pneumoniae strains is now resistant to penicillin and sometimes to third-generation cephalosporin, it is necessary to reevaluate the initial therapy of bacterial meningitis proposed before identification of the organism and its susceptibility pattern. POPULATION: From 1 January 1992 to 31 March 1994, nine children with acute S pneumoniae meningitis were treated with ceftriaxone plus aminoglycoside as conventional initial therapy. Eight children were less than 1 year-old (five from 3 to 6 months). Five S pneumoniae strains were penicillin-resistant; four had a ceftriaxone minimal inhibitory concentration (MIC) of 0.047 to 0.094 mg/L and one of 1.5 mg/L. Ceftriaxone was given intravenously at doses of 50 mg/kg twice a day to patients less than 12 months old and 100 mg/kg once a day to patients older than 12 months. Intravenous amikacin (7.5 mg/kg twice daily) or netilmicin (3 mg/kg twice daily) were administered in combination. Dexomethasone was given to all children as adjunctive therapy. Follow-up lumbar puncture was performed after 24 to 36 hours of treatment. RESULTS: For each of the nine patients, cerebrospinal fluid was sterile with normal glucose level. After 2 or 4 days, initial therapy had been modified according to antibiogram and MIC. Monotherapy with ceftriaxone was continued in five children. Rifampicin was associated with initial bitherapy in one case. In two other patients, initial empiric therapy was stopped and changed to chloramphenicol. CONCLUSION: No case of bacteriological failure was noted in our patients but evolution of epidemiology and emergence of decreased penicillin sensibility in S pneumoniae strains (55% in our study) suggests that a third antibiotic (vancocin or rifampicin) should be associated with the standard first-line drug when S pneumoniae is suspected.

Adolescent↗
PubMed1996

Doppler ultrasound imaging: a new technique to detect lung hypoplasia before birth?

Combined color-coded Doppler and pulsed Doppler ultrasonography allows visualization of the fetal pulmonary circulation and study of pulmonary blood flow velocity waveforms. Systolic and diastolic changes were observed in fetal pulmonary artery flow velocity waveforms in a case of fetal pulmonary hypoplasia at 34 weeks of gestation. This observation supports our hypothesis that Doppler velocimetry can detect lung hypoplasia based on post- mortem examination of decreased total size of the pulmonary vascular bed, decreased number of pulmonary vessels per unit lung tissue and increased pulmonary vascular muscularization.

Adult↗
PubMed1996

Effect of cell polarization and differentiation on entry of Listeria monocytogenes into the enterocyte-like Caco-2 cell line.

The entry of Listeria monocytogenes into the enterocyte-like Caco-2 cell line was studied as a function of cell polarization and differentiation. L. monocytogenes entered through the entire surface of nonpolarized cells and, predominantly, through the basolateral surface of polarized cells based on the following observations: (i) sites of L. monocytogenes invasion paralleled the distribution of the transferrin receptor, a well-known basolateral marker of polarization; (ii) numbers of internalized bacteria decreased dramatically when Caco-2 monolayers cultured beyond confluency were used (about 0.1% of the inoculated bacteria versus 1 to 2% with nonconfluent monolayers); and (iii) L. monocytogenes entry into postconfluent monolayers was greatly enhanced by treating cells with Ca(2)+ -free medium, a procedure that disrupts intercellular junctions and thus exposes the basolateral surface to bacteria. Ethylene glycol-bis (beta-aminoethyl ether)-N, N, N',N' -tetraacetic acid (EGTA) had contradictory effects on L. monocytogenes entry as this reagent opened intercellular junctions but inhibited binding and internalization of bacteria. Finally, the role of the inlAB locus in L. monocytogenes entry was confirmed because and inlAB mutant was 50- to 100-fold less invasive than the parental strain regardless of the monolayer's age. However, the inlAB mutant was still able to enter cells and to induce intracellular actin polymerization. Entry of inlAB bacteria into Caco-2 cells was not inhibited by EGTA.

Bacterial Adhesion↗
PubMed1996

Serodiagnosis of listeriosis based upon detection of antibodies against recombinant truncated forms of listeriolysin O.

Amino-terminal fragments of listeriolysin O (LLO) of 240 and 411 residues (fragments LLO240 and LLO411, respectively) were expressed in Escherichia coli as fusion polypeptides with maltose-binding protein (MBP) with the aim of producing specific antigens for use in serological tests. In Western blots (immunoblots) with crude bacterial extracts of the fusion polypeptides, the reactivities of MBP-LLO240 and MBP-LLO411 with anti-LLO antibody (ALLO)- and anti-streptolysin O antibody (ASLO)-positive human sera were first compared with that of the entire LLO (LLO530) also fused to MBP (MBP-LLO530). Sixteen of 17 (94.1%) ALLO-positive samples reacting with MBP-LLO530 also reacted with MBP-LLO411, whereas this proportion dropped to 11 of 17 (64.7%) with MBP-LLO240. Alternatively, 18 of 19 (94.7%) ASLO-positive samples giving an interpretable result reacted with MBP-LLO530, whereas 1 of 19 (5.3%) of these samples reacted with MBP-LLO240 or MBP-LLO411. The fusion polypeptide MBP-LLO411 was purified by maltose affinity chromatography and was further evaluated as a diagnostic antigen in a Western blot assay. Twenty-one of 21 (100%) serum samples obtained from patients with listeriosis and found to be positive for ALLO by a reference dot blot test reacted with MBP-LLO411, whereas 1 of 20 (5%) ASLO-positive serum samples and 1 of 100 (1%) serum samples from healthy adults were reactive. Thus, a polypeptide limited to the 411 amino-terminal residues of LLO is a specific and sensitive antigen for the detection of ALLO.

Adolescent↗