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Biomedical subjects

D Aubert

Publications and source records attributed to D Aubert.

At least 55 records · Page 3Linked to original sources
PubMed2000

Molecular and biochemical heterogeneity of class B carbapenem-hydrolyzing beta-lactamases in Chryseobacterium meningosepticum.

Although the carbapenem-hydrolyzing beta-lactamase (CHbetaL) BlaB-1 is known to be in Chryseobacterium meningosepticum NCTC 10585, a second CHbetaL gene, bla(GOB-1), was cloned from another C. meningosepticum clinical isolate (PINT). The G+C content of bla(GOB-1) (36%) indicated the likely chromosomal origin of this gene. Its expression in Escherichia coli DH10B yields a mature CHbetaL with a pI of 8.7 and a relative molecular mass of 28.2 kDa. In E. coli, GOB-1 conferred resistance to narrow-spectrum cephalosporins and reduced susceptibility to ureidopenicillins, broad-spectrum cephalosporins, and carbapenems. GOB-1 had a broad-spectrum hydrolysis profile including penicillins and cephalosporins (but not aztreonam). The catalytic efficiency for meropenem was higher than for imipenem. GOB-1 had low amino acid identity with the class B CHbetaLs, sharing 18% with the closest, L-1 from Stenotrophomonas maltophilia, and only 11% with BlaB-1. Most of the conserved amino acids that may be involved in the active site of CHbetaLs (His-101, Asp-103, His-162, and His-225) were identified in GOB-1. Sequence heterogeneity was found for GOB-1-like and BlaB-1-like beta-lactamases, having 90 to 100% and 86 to 100% amino acid identity, respectively, among 10 unrelated C. meningosepticum isolates. Each isolate had a GOB-1-like and a BlaB-1-like gene. The same combination of GOB-1-like and BlaB-1-like beta-lactamases was not found in two different isolates. C. meningosepticum is a bacterial species with two types of unrelated chromosome-borne class B CHbetaLs that can be expressed in E. coli and, thus, may represent a clinical threat if spread in gram-negative aerobes.

Amino Acid Sequence↗
PubMed2000

Recombinant antigens to detect Toxoplasma gondii-specific immunoglobulin G and immunoglobulin M in human sera by enzyme immunoassay.

We have evaluated the diagnostic utility of eleven Toxoplasma gondii recombinant antigens (P22 [SAG2], P24 [GRA1], P25, P28 [GRA2], P29 [GRA7], P30 [SAG1], P35, P41 [GRA4], P54 [ROP2], P66 [ROP1], and P68) in immunoglobulin G (IgG) and IgM recombinant enzyme-linked immunosorbent assays (Rec-ELISAs). Following an initial evaluation, six recombinant antigens (P29, P30, P35, P54, P66, and P68) were tested in the IgG and IgM Rec-ELISAs with four groups of samples which span the toxoplasmosis disease spectrum (negative, chronic infection, acute infection, and recent seroconversion). Our results suggest that the combination of P29, P30, and P35 in an IgG Rec-ELISA and the combination of P29, P35, and P66 in an IgM Rec-ELISA can replace the tachyzoite antigen in IgG and IgM serologic tests, respectively. The relative sensitivity, specificity, and agreement for the IgG P29-P30-P35 Rec-ELISA were 98.4, 95.7, and 97.2%, respectively. The resolved sensitivity, specificity, and agreement for the IgM P29-P35-P66 Rec-ELISA were 93.1, 95.0, and 94. 5%, respectively. Relative to the tachyzoite-based immunocapture IgM assay, the IgM P29-P35-P66 Rec-ELISA detects fewer samples that contain IgG antibodies with elevated avidity from individuals with an acute toxoplasmosis.

Animals↗
PubMed1999

In vivo retrovirus-mediated gene transfer to the liver of dogs results in transient expression and induction of a cytotoxic immune response.

Gene transfer in regenerating dog liver using high-titer recombinant retroviral vectors carrying the E. coli beta-galactosidase gene was studied. Supernatants containing amphotropic or gibbon ape pseudotyped recombinant retroviruses were infused into a peripheral vein in beagle dogs after partial hepatectomy. The kinetics of liver regeneration were determined in the animals and daily infusions were carried out for 4 or 5 days during the regeneration period. Up to 2.8% of hepatocytes were beta-galactosidase positive at the end of the procedure. However, the number of positive cells declined rapidly and few positive hepatocytes were detected after 3 weeks. PCR demonstrated the disappearance of the provirus. Histologically, inflammatory lesions were observed in the transduced livers. Finally, we demonstrated the presence of a cytotoxic T lymphocyte immune response directed against beta-galactosidase-expressing cells, which could explain the disappearance of the transgene. This work suggests that the efficiency of in vivo gene delivery using high-titer retroviral vectors directly infused into the circulation may be hampered by a cytotoxic immune response against the infected cells.

Animals↗
PubMed1999

Intrapericardial teratoma diagnosed prenatally in a twin fetus.

Prenatal diagnosis at 32 weeks' gestation of an anteromediastinal tumor in a twin fetus allowed immediate neonatal intensive management after delivery at 34 weeks' gestation. At 48 h of age the patient underwent a median sternotomy; complete resection of the tumor was possible. Histologically, it was a mature teratoma. At age 1 year both twins are well.

Adult↗
PubMed1999

Tracheobronchial ruptures from blunt thoracic trauma in children.

BACKGROUND/PURPOSE: Tracheobronchial ruptures in blunt thoracic trauma in children are rare. The aim of this study was to suggest the means of an early diagnosis and a conservative management as often as possible. METHODS: Sixteen cases of tracheobronchial ruptures by blunt thoracic trauma were observed over 26 years in 9 regional pediatric centers. RESULTS: There were 12 boys and 4 girls, from ages 1 hour to 17 years. Nine children presented with associated lesions. Fibroscopy established the following diagnosis: 8 tracheal wounds and 8 bronchial wounds. Six children were operated on within 18 hours (on average) after installation of a thoracic drainage. Two lobectomies, 3 ideal tracheal sutures, and 1 bronchial suture were performed. Seven children were treated exclusively by thoracic drainage. Two of them were intubated through the lesion, leading to a transitory endoprothesis accompanied or not by an external thoracic drainage. One infant recovered spontaneously. There were no deaths in this series. Two recurrent postoperative nerve injuries were noted, one of which was a transitory spontaneously resolutive scar bud and one a granuloma treated by laser. Three times, a stenosis occurred after a conservative management. Two were operated on. CONCLUSIONS: Tracheobronchial ruptures in children are rare. An early fibroscopy holds an important place in the approach of this pathology. Treatment is variable, based on thoracic lesions, their tolerance by the child, and associated lesions. Surgery is not the only therapy because conservative treatment by simple thoracic drainage or lesion intubation has proved effective.

Adolescent↗
PubMed1999

Unexpected and coordinated expression of Spi-1, Fli-1, and megakaryocytic genes in four Epo-dependent cell lines established from transgenic mice displaying erythroid-specific expression of a thermosensitive SV40 T antigen.

Most erythroleukemic cell lines established in vitro coexpress erythrocytic and megakaryocytic markers that often are associated with expression of Spi-1 and/or Fli-1 transcription factors known as transactivators of megakaryocyte-specific promoters. In the present study, we examined the possibility of establishing new cell lines keeping strictly erythroid-specific properties in vitro through the targeted and conditional immortalization of erythrocytic progenitors. For that purpose, we established several lines of transgenic mice displaying erythroid-specific expression of a thermosensitive SV40 T antigen. As expected, these transgenic mice developed splenomegaly due to the massive amplification of Ter 119 positive erythroid nucleated cells expressing T antigen. Despite this drastic effect in vivo, the in vitro immortalization of erythropoietin-dependent erythroid progenitors unexpectedly occurred at low frequency, and all four cell lines established expressed both erythrocytic (globins) and megakaryocytic markers (glycoprotein IIb, platelet factor 4) as well as Spi-1 and Fli-1 transcripts at permissive temperature. Switching the cells to the nonpermissive temperature led to a marked increase in globin gene expression and concomitant decrease in expression of Spi-1, Fli-1, and megakaryocytic genes in an erythropoietin-dependent manner. Interestingly, enhanced expression of Spi-1 and Fli-1 genes already was detected in the Ter 119 positive cell population of transgenic mice spleen in vivo. However, like normal Ter 119 erythroid cells, these Ter 119 positive cells from transgenic mice still expressed high levels of beta-globin and very low or undetectable glycoprotein IIb and platelet factor 4 megakaryocytic transcripts. Taken together, these data indicate that the unexpected expression of megakaryocytic genes is a specific property of immortalized cells that cannot be explained only by enhanced expression of Spi-1 and/or Fli-1 genes.

Animals↗
PubMed1999

Meiotic instability of human minisatellite CEB1 in yeast requires DNA double-strand breaks.

Minisatellites are tandemly repeated DNA sequences of 10-100-bp units. Some minisatellite loci are highly unstable in the human germ line, and structural analysis of mutant alleles has suggested that repeat instability results from a recombination-based process. To provide insights into the molecular mechanism of human minisatellite instability, we developed Saccharomyces cerevisiae strains carrying alleles of the most unstable human minisatellite locus, CEB1 (ref. 2). We observed that CEB1 is destabilized in meiosis, resulting in a variety of intra- and inter-allelic gains or losses of repeat units, similar to rearrangements described in humans. Using mutations affecting the initiation of recombination (spo11) or mismatch repair (msh2 pms1 ), we demonstrate that meiotic destabilization depends on the initiation of homologous recombination at nearby DNA double-strand break (DSBs) sites and involves a 'rearranged heteroduplex' intermediate. Most of the human and yeast data can be explained and unified in the context of DSB repair models.

Alleles↗
PubMed1999

Cricopharyngeal achalasia--a cause of major dysphagia in a newborn. A case report.

Cricopharyngeal achalasia is a rare cause of neonatal dysphagia. Its treatment is based on surgical myotomy, which is to be avoided in the presence of prematurity and neurological diseases. The authors report a case of cricopharyngeal achalasia in a full-term four-month-old female baby. Coughing and choking during feeds were the major symptoms. The diagnosis was made peroperatively although barium meal and endoscopic findings were suggestive. After cricopharyngeal myotomy, symptoms took several weeks to disappear. Seven months after surgery, she feeds normally and weighs 7,700 g. Neonatal cricopharyngeal achalasia could be a foregoing state to cricopharyngeal diverticula in adult. Some cases may remain undiagnosed either due to lack of symptoms or sudden infant death.

Cricoid Cartilage↗
PubMed1999

Detection of specific immunoglobulin E during maternal, fetal, and congenital toxoplasmosis.

Toxoplasma immunoglobulin E (IgE) antibodies in 664 serum samples were evaluated by using an immunocapture method with a suspension of tachyzoites prepared in the laboratory in order to evaluate its usefulness in the diagnosis of acute Toxoplasma gondii infection during pregnancy, congenital infection, and progressive toxoplasmosis. IgE antibodies were never detected in sera from seronegative women, from patients with chronic toxoplasma infection, or from infants without congenital toxoplasmosis. In contrast, they were detected in 86.6% of patients with toxoplasmic seroconversion, and compared with IgA and IgM, the short kinetics of IgE was useful to date the infection precisely. For the diagnosis of congenital toxoplasmosis, specific IgE detected was less frequently than IgM or IgA (25 versus 67.3%), but its detection during follow-up of children may be interesting, reflecting an immunological rebound. Finally, IgE was detected early and persisted longer in progressive toxoplasmosis with cervical adenopathies, so it was also a good marker of the evolution of toxoplasma infection.

Adolescent↗
PubMed1999

Evaluation of the fungitest kit by using strains from human immunodeficiency virus-infected patients: study of azole drug susceptibility.

One hundred eighteen Candida clinical isolates from human immunodeficiency virus-infected patients were tested for their susceptibilities to fluconazole and itraconazole by Fungitest and the National Committee for Clinical Laboratory Standards MIC method. Fungitest results depended on both yeast species and antifungal agents. This test is able to detect sensitive strains (97% agreement with results of the MIC method in tests with fluconazole and 84% agreement in tests with itraconazole) but has a poor capacity to detect resistant strains (26% agreement in tests with fluconazole and 5% agreement in tests with itraconazole).

AIDS-Related Opportunistic Infections↗
PubMed1999

[Epididymal cysts in adolescents].

Epididymal tumours are uncommon in children and adolescents and are usually benign. Epididymal cyst is exceptionally reported in the literature, although it is certainly underdiagnosed. The authors report 3 cases of epididymal cyst in 3 children, 12, 14 and 16 years of age. These children presented with an uncomfortable scrotal mass and were treated by excision of the cyst in every case. The aetiology of epididymal cysts is unclear. It is probably a congenital abnormality related to hormonal disorders during embryonic life. Physical examination is very important, but not sufficient for the diagnosis and must be completed by scrotal ultrasonography, which shows an echo-free cystic epididymal structure. Despite ultrasonography, the differential diagnosis of other scrotal cystic masses and even some solid epididymal tumours, which may present all of the sonographic characteristics of a cyst, must be considered. The treatment of symptomatic epididymal cyst in children must be surgical. For asymptomatic cysts diagnosed by sonography, clinical follow-up to document stability of the mass is justified.

Adolescent↗
PubMed1999

[Intravesical morphine analgesia in pediatric urology].

OBJECTIVE: Evaluation of the technique and value of intravesical morphine instillation after ureterovesical reimplantation in children. MATERIAL AND METHODS: From July 1997 to June 1998, the Duckett protocol (Philadelphia, USA), comprising slow intravesical infusion of morphine for the first three prosoperative days, was applied in 25 children aged five months to twelve years after ureterovesical reimplantation surgery, without bladder catheterization. Postoperative pain was evaluated by CHEOPS and VAS scales and by all nursing staff by an anonymous questionnaire. RESULTS: Analgesic assessment tests confirmed a significant improvement of postoperative comfort, despite the absence of a bladder catheter. No adverse effects or complications related to intravesical morphine instillation were observed. CONCLUSION: Intravesical morphine instillation is an easy, effective postoperative analgesia technique, allowing good tolerance of the absence of postoperative bladder catheterization.

Administration, Intravesical↗
PubMed1999

[Prognostic factors of secondary complications in pediatric traumatology: a prospective study of 700 patients].

BACKGROUND: The objective of the study was to estimate prevalence of therapeutic complications in a department of orthopedics pediatric surgery, and to determine predictors of minor and serious complications. METHODS: Between November 1996 and 1997, children less than or equal to 17 years of age, admitted for bone fracture (head and face excepted) were selected in a prospective study. In all, 700 children were treated until bone consolidation. Individual, socio-economic, anatomical, environmental and therapeutic factors were progressively registered. All complications were noted. RESULTS: The mean age of the children was 9.2 years; 25 patients could not be traced. Prevalence rate of therapeutic complications was 10.3%. In multivariate analysis using logistic regression, six factors increased the risk of adverse event: kind of fracture (diaphysial), comminuted aspect, compounded fracture and bone displacement, season (spring and autumn), and use of medical transport between accident place and hospital. The same factors, season and compounded fracture excepted, were predictors of serious complications. CONCLUSION: The results show that therapeutic complications depend on anatomical and environmental factors above all, and that medical procedure is not a prognosis factor. So if prevention of fractures is possible before injury, a better knowledge of initial risk can improve prevention of complications.

Adolescent↗
PubMed1998

Expression patterns of GASA genes in Arabidopsis thaliana: the GASA4 gene is up-regulated by gibberellins in meristematic regions.

The GASA gene family previously identified in Arabidopsis belongs to a wide-spread class of genes found in mono- and dicotyledonous plants, all structurally related to the original GA-regulated GAST1 gene from tomato. They encode small peptides (97 to 112 residues) of unknown function sharing a 60 amino acid conserved C-terminal domain comprising twelve conserved cysteine residues which define a pattern not related to other known cysteine-rich motifs. Northern blot hybridization analysis revealed sequential expression of three genes during flowering, silique development and seed germination. GASA4 transcripts were detected in flower buds. GASA1 transcripts markedly accumulated in siliques, about five days after pollination, and correlated with the peak of GA biosynthesis at this stage of silique development. GASA3 transcripts accumulated at the end of the maturation stage of the silique, and transcripts were still present in dry seeds but degraded rapidly during imbibition. In addition, the GASA4 gene was again actively transcribed after germination and this expression was shown to be dependent on the presence of GAs in GA-deficient mutants. Immunoblot analysis confirmed the presence of the GASA4 gene product in flower buds, seedlings and roots. We focused on the GASA4 gene and characterized its expression. The upstream region (-890 to +128) was fused to the GUS reporter gene. GASA4/GUS expression was detected in transgenic Arabidopsis primarily in all meristematic regions, including vegetative, inflorescence and floral meristems, as well as primary and lateral root tips. In a GA-deficient background (ga1-3), GUS activity in the vegetative meristem was detected only in the presence of supplied GA. In root and flower meristems, basal GUS activity was slightly enhanced by exogenous GA. Interestingly, GA strongly inhibit GUS activity in expanding cotyledons and leaves in ga1-3 mutants supplied with exogenous GAs, as well as in the wild type. The GA-dependent meristem-specific expression pattern suggests that the GASA4 protein plays a role in dividing cells rather than in elongating cells.

Amino Acid Sequence↗
PubMed1998

Interferon-gamma signal transduction during parasite infection: modulation of MAP kinases in the infection of human monocyte cells (THP1) by Toxoplasma gondii.

We assayed mitogen-activated protein (MAP) kinase phosphorylation in a human monocyte cell line (THP1) during their infection by Toxoplasma gondii. In addition, we tested the effect of specific MAP kinase inhibitors (PD098059 and SB203580) on parasite invasion. MAP kinase phosphorylation was increased in the cytosol and membrane fractions of THP1 infected with T. gondii. The MAP kinase phosphorylation of uninfected THP1 cells was not significantly modified by incubation for 20 h with 1000 U/ml of IFN-gamma. However, IFN-gamma treatment of infected cells significantly reduces the increase in phosphorylation caused by parasite infection. There was also MAP kinase activity in the cytosol and membrane fractions of extracellular T. gondii tachyzoites. IFN-gamma altered the distribution of activity in subcellular fractions of extracellular T. gondii tachyzoites. This indicates that IFN-gamma directly affects parasite MAP kinase activity. The results provide evidence that MAP kinase pathways participate in the infection by T. gondii and that the decrease in MAP kinase activity in infected cells caused by IFN-gamma may be involved in mediating their protective signals.

Calcium-Calmodulin-Dependent Protein Kinases↗
PubMed1998

Pyrimethamine-sulfadoxine treatment of congenital toxoplasmosis: follow-up of 78 cases between 1980 and 1997. Reims Toxoplasmosis Group.

UNLABELLED: The purpose of this study was to determine the clinical and immunological outcome of 78 children with congenital toxoplasmosis treated with the pyrimethamine-sulfadoxine combination between 1980 and 1997. METHODS: Children were divided into 3 groups according to the initial duration of treatment (always including folinic acid, 5 mg/week by mouth), as follows: pyrimethamine (1.25 mg/kg every 15 d) + sulfadoxine (25 mg/kg every 15 d) for 12 months (Group 1, 47 children), or for 24 months, with or without prenatal therapy (respectively, Group 2, 19 children, and Group 3, 12 children). RESULTS: Chorioretinitis occurred in 23% of these 78 children. Four children had unilateral blindness, 1 had mild epileptic fits and 1 had psychomotor retardation. The lowest rate of sequelae were in Groups 2 and 3. Immunological rebounds, generally without clinical repercussions, occurred frequently (90% of cases on average) during, or more often after therapy, regardless of the treatment duration. Treatment was always well tolerated. CONCLUSIONS: Our current treatment strategy for congenital toxoplasmosis consists of a 24-month course of pyrimethamine-sulfadoxine (Fansidar) combined with folinic acid (Lederfoline). If the prenatal diagnosis is positive, we also prescribe this treatment to the mother until delivery. This combination offers satisfactory compliance, adequate serum concentrations, and good preventive efficacy.

Adolescent↗
PubMed1998

Molecular fingerprinting of Mycobacterium tuberculosis and risk factors for tuberculosis transmission in Paris, France, and surrounding area.

Forty-three percent of the tuberculosis cases reported in France are from the Ile de France region. The incidence of tuberculosis in this region is 33 cases per 100,000 inhabitants, twice the national average. A restriction fragment length polymorphism (RFLP) analysis was performed with clinical isolates of Mycobacterium tuberculosis isolated during 1995 in 10 hospitals in Paris and surrounding areas to detect tuberculosis transmission and define the factors associated with clustering in this population. The molecular markers used were the insertion sequence IS6110 and the direct repeat (DR) sequence. Social, demographic, and clinical data were collected from the patients' medical files. Ten patients with isolates with a single copy of IS6110 were excluded from further analysis. Twenty-four patients with false-positive cultures due to laboratory contamination (based on RFLP analysis with IS6110 and examination of patient data) were also excluded. The study was then conducted with 272 strains isolated from 272 patients. Further fingerprinting was performed by using the DR element with strains with patterns by RFLP analysis with IS6110 that differed by one band only and strains with identical patterns by RFLP analysis with IS6110 and with low numbers of copies of IS6110. The combined use of both markers identified unique patterns for 177 strains and clustered 95 (35.7%) strains in 26 groups, each containing isolates from 2 to 12 patients. The clustering was strongly associated with homelessness and the male sex. It was not associated with age, birth in a foreign country, human immunodeficiency virus positivity, or residence in hostels or prison. Isolates from homeless people were often included in large clusters, and homeless people could be the source of tuberculosis transmission for more than 50% of the clustered patients. These results suggest that homeless people play a key role in the spread of M. tuberculosis in the community and that poor socioeconomic conditions are the main risk factors associated with active tuberculosis transmission.

AIDS-Related Opportunistic Infections↗