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Biomedical subjects

D Aubert

Publications and source records attributed to D Aubert.

At least 19 recordsLinked to original sources
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

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↗
PubMed1997

Accelerated detection of DNA on membranes by automated enzyme-linked immunofiltration assay.

Methods used to detect DNA after transfer to nitro-cellulose or nylon membranes are all based on slow incubation with agitation. We describe an application of the ELIFA technique (enzyme-linked immunofiltration assay) for rapid detection of DNA immobilized on a membrane by active filtration of the reagents across the membrane. The different steps (saturation, hybridization to a nonisotopically labeled probe, washing, and immunoenzymatic revelation) are automated and controlled by a microcomputer that determines the direction of flow and flow rates of the solutions through the membrane. We applied this method to the detection of Toxoplasma gondii DNA in 108 samples of amniotic fluid during antenatal tests for toxoplasmosis and compared the results with those obtained by the conventional method. In addition to a major time saving (2 h against almost 15 h), automation improves reproducibility and avoids manipulation of the membranes between the different steps, while keeping the same sensitivity and specificity as the standard method.

Amniotic Fluid↗
PubMed1997

Cystic rectal duplication: a rare cause of neonatal intestinal obstruction.

A case of cystic rectal duplication revealed on day 2 of life by a low intestinal occluding syndrome is reported. Radiologic imaging (ultrasonography, cystography, rectography) showed a large, retrorectal liquid formation in the pelvis and abdomen, with pelvic compression of the terminal alimentary canal and lower urinary tract. Magnetic resonance imaging demonstrated a liquid formation with clearly defined edges and no medullary involvement, thus ruling out the possibility of a previous meningeal hernia. Biological markers were within normal limits. On day 4, a 9 x 6-cm cystic rectal duplication was removed, followed by a temporary colostomy. Pathologic examination demonstrated typical rectal architecture with ciliated cells. Radiologic and clinical findings at 2-month follow-up were reassuring. This case report is exceptional for the following reasons: (1) As a rule, rectal duplications are relatively rare (70 cases reported in the literature); (2) The means of disclosing a neonatal rectal duplication is unusual (4 cases reported in the literature); (3) The volume of the malformation was considerable; and (4) Heterotopic ciliated epithelium was present.

Cysts↗
PubMed1997

Localized esophageal leiomyoma and hypertrophic osteoarthropathy.

The authors report the case study of a 13-year-old girl, suffering from epigastric pain related to an important infectious syndrome and from marked hypertrophic pneumosteopathy (clubbed fingers, diffuse cortical hyperostosis). Radiological examination (chest x-ray and computed tomography scan) showed a partly calcified right posterior mediastinal mass. The esophagoscopy showed a fistular emanation from the esophagus to the tumor. The biopsy results were of no diagnostic significance, and the samples demonstrated a bacterial and fungal colonization. An endoscopic sonogram showed an inhomogeneous mass with hyperechoic structures developed between the mucosa and the outer muscular coat of the esophagus. The patient underwent surgery, which showed a large intraparietal tumor of the esophagus, which, through pathological examination, was confirmed to be a benign leiomyoma. Postoperative follow-up was simple and the pneumosteopathic symptoms regressed rapidly. This disease is rare in children under 15 years of age. It is only exceptionally associated with a hypertrophic pneumosteopathy. This pathology is diagnostically challenging to the surgeon. The endoscopic ultrasonography is the best procedure in the assessment of subepithelial tumor and extrinsic compressions of the oesophagus.

Adolescent↗
PubMed1997

Treatment of Madelung's deformity by lengthening and reaxation of the distal extremity of the radius by Ilizarov's technique.

Madelung's deformity was first described in 1878. It is characterised by a typical deformity of the carpus and not only causes pain but also impedes mobility and aesthetic appearance. Surgical correction can be effected during adolescence, the most frequently employed technique being conical osteotomy. We present a novel technique of lengthening and aligning the distal radial extremity using Ilizarov's technique. Five carpal joints were operated on in three 13-year old girls. An aesthetic effect was obvious in all the cases. Mobility improved by 30 degrees in the direction of the extension and pain always subsided directly after surgery.

Adolescent↗
PubMed1997

Detection of Cryptosporidium parvum DNA in formed human feces by a sensitive PCR-based assay including uracil-N-glycosylase inactivation.

We developed a PCR-based method that can be used to identify Cryptosporidium parvum in human feces. Fecal oocysts were concentrated by centrifugation on a sodium chloride gradient and filtration on a nitrocellulose filter prior to DNA extraction and PCR amplification of a 452-bp C. parvum-specific DNA sequence with a protocol including dUTP and uracil-N-glycosylase. All samples obtained from naturally infected humans (n = 10), calves (n = 4), and goats (n = 2) were positive. A 100% detection rate was achieved with both formed and solid stools (n = 10) seeded with 1,000 C. parvum oocysts per g. Procedures based on stool concentration by a modified Ritchie method and subsequent oocyst identification by immunofluorescent labeling or acid-fast staining require concentrations of 50,000 to 500,000 oocysts per g to achieve a 100% detection rate with formed stools. The described PCR-based assay thus has a 50- to 500-fold increase in sensitivity compared to those of the methods commonly used to analyze formed feces.

Animals↗
PubMed1997

Molecular-cytogenetic detection of a deletion of 1p36.3.

We report a deletion of 1p36.3 in a child with microcephaly, mental retardation, broad forehead, deep set eyes, depressed nasal bridge, flat midface, relative prognathism, and abnormal ears. The phenotype is consistent with that described for partial monosomy for 1p36.3. Reverse chromosome painting and microsatellite and Southern blot analyses were used to map the extent of the deletion. Fluorescence in situ hybridisation (FISH) analysis using probes from every telomere indicates that the rearrangement is likely to be a chromosomal truncation or rearrangement involving subtelomeric repetitive DNA. The deletion was identified by screening a sample of children and adults with idiopathic mental retardation. In conjunction with previous work on this sample, we estimate that 7.4% of the group have subtelomeric rearrangements.

Adolescent↗
PubMed1996

Antenatal finding of intestinal obstruction caused by isolated segmental jejunal dilatation: a case report.

The authors report a case of segmental jejunal dilatation that was discovered antenatally and manifested clinically as lower obstruction in a newborn boy. The antenatal ultrasound findings at 29, 30, and 31 weeks' gestation showed a constant hypoechogenic image (6 x 3 cm in diameter) localized to the right flank of the fetal abdomen, thought to be situated in the right colon. A prenatal diagnosis of incomplete right colonic stenosis was considered. In the immediate postnatal period, there were clinical manifestations of intestinal obstruction; however, results of a contrast enema and rectal biopsies were normal. An upper gastrointestinal contrast study showed a dilated jejunal loop situated approximately 15 cm from the ligament of Treitz. During surgery, a large dilated jejunal loop (7 cm in diameter, 15 cm in length) was found and resected. Histopathologic examination confirmed the diagnosis of segmental jejunal dilatation. This is the first antenatal illustration of this rare pathology, and it supports the hypothesis of a congenital origin for this anomaly.

Adult↗
PubMed1996

Artificial urinary sphincter implantation for neurogenic bladder: a multi-institutional study in 107 children.

OBJECTIVES: To evaluate the outcome of implantation of the AMS 800 artificial urinary sphincter in children with neurogenic bladder. PATIENTS AND METHODS: The records of 107 children (74 boys and 33 girls) treated for neurogenic urinary incontinence by implantation of the AMS 800 artificial sphincter between 1983 and 1993 were reviewed retrospectively. The underlying cause of incontinence in 92 patients was spina bifida, the mean age at implantation was 13.7 years and 30 patients had undergone previous bladder neck surgery. Implantation was carried out in combination with another surgical procedure in 24.3% of patients. The mean follow-up was 61 months (minimum 12). RESULTS: The mean operational life of the sphincter was 56 months. No deaths occurred but removal of the artificial sphincter was necessary in 20 patients (19%). Surgical revision was not required in 44 patients (41%) but at least one revision was performed in 63 and more than one in 42. There were 21 mechanical failures, 40 surgical complications and 39 cases involving changes in the dynamics of bladder function. Of the 87 children (81%) in whom the device is still in place, 72 are completely continent (83%), 10 are slightly wet, and five are incontinent. The overall success rate was 77%. CONCLUSIONS: The results emphasize that for successful implantation of an artificial urinary sphincter in children, the pre-operative bladder capacity must be sufficient and previous surgery should not have been performed on the bladder neck, the site of choice for implantation in children. Sphincterotomy is not always necessary in paediatric patients. Children and parents should be informed of the high complication rate and the need for long-term follow-up.

Adolescent↗
PubMed1996

LITTLE KEVIN: a program for the estimation of protein homology by analysing the amino acid compositions and sequences.

We present here a computational method based on the analysis of amino acid composition for performing comparisons between proteins. This user-friendly and reliable test is aimed at rapidly identifying, from data-base subsets, sequences--if necessary, partial sequences--which share similar amino acid compositions to the input composition (deduced from experimental results). Apparent molecular weight (as determined by SDS-PAGE) and artefactual modifications due to the experimental determination of the amino acid composition are taken into account to perform the comparison. This program thus constitutes a useful tool in searching for the probable identification of either non-sequenced proteins or peptides from hydrolysed proteins.

Algorithms↗
PubMed1996

Early neonatal diagnosis of congenital toxoplasmosis: value of comparative enzyme-linked immunofiltration assay immunological profiles and anti-Toxoplasma gondii immunoglobulin M (IgM) or IgA immunocapture and implications for postnatal therapeutic strategies.

Diagnostic strategies for congenital toxoplasmosis have changed profoundly in recent years. Immunological diagnostic methods, long considered disappointing, can now be used at a very early stage. Over a 3-year period, 1,050 infants at risk of congenital toxoplasmosis (born to 1,048 mothers infected during pregnancy) were monitored for a minimum of 12 months and a maximum of 7 years. More than 6,000 serum specimens were analyzed by comparative mother-infant immunological profiles (CIPs) based on an enzyme-linked immunofiltration assay (ELIFA) and an immunocapture method for the detection of specific immunoglobulin M (IgM) and IgA. IgG antibodies were also titrated. One hundred three cases of congenital toxoplasmosis were demonstrated. The CIP-ELIFA method had a better diagnostic yield (sensitivity, 90%) than specific IgM and/or IgA detection by immunocapture assay (sensitivity, 77%). By using a combination of these tests, congenital infection was diagnosed in the first month and the first 3 months of life in 90 and 94% of infants with toxoplasmosis, respectively, with a specificity of 99.8% and a positive predictive value of 99% at 8 months of age. This dual diagnostic approach (ELIFA and IgM-IgA immunocapture) is highly efficient and has important implications for therapy. Indeed, early postnatal diagnosis based on objective evidence enables therapy with pyrimethamine-sulfadoxine to be started immediately for 24 months, while spiramycin (which used to be given preventively for 9 to 12 months to all infants at risk) can be stopped after the first 3 months of life.

Animals↗
PubMed1996

Detection of Toxoplasma gondii in immunodeficient subjects by gene amplification: influence of therapeutics.

Polymerase chain reaction (PCR) technology was used to detect Toxoplasma gondii DNA in 253 immunodeficient subjects, 179 of whom were infected with the human immunodeficiency virus (HIV). The incidence of toxoplasmosis was 12.3% (22/179) in the HIV-infected subjects and 2.7% (2/74) in the remainder. The sensitivity of the PCR during episodes of toxoplasmosis in HIV-infected subjects not on antiparasitic treatment was 86.6% on peripheral blood and 60% on cerebrospinal fluid (CSF), but was only 25% and 16.7%, respectively, in subjects receiving specific treatment or prophylaxis against Pneumocystis carinii. Among the HIV-seronegative population, six patients undergoing anticancer chemotherapy were PCR positive on bronchoalveolar lavage fluid but did not develop pulmonary toxoplasmosis, suggesting transient carriage.

Animals↗
PubMed1995

Automated reading and processing of quantitative IgG, IgM, IgA, and IgE isotypic agglutination results in microplates. Development and application in parasitology-mycology.

Microplate agglutination techniques represent a simple and commonly used approach for the quantitative or qualitative isotypic analysis of specific antibodies. However, they require optical reading by the investigator and are thus prone to an important degree of variability. In order to solve some of the problems associated with the variability of optical readings, we have used an automatic reader scanning each of the 96 wells of a standard microplate in 32 different locations. The inherent advantages of the automatic reader were further maximized by coupling it to a dedicated computer running customized software designed to process data coming on-line from the spectrophotometer. This approach has been applied to the diagnosis of human toxoplasmosis and candidosis. Suspensions of Toxoplasma gondii tachyzoites or of sensitised erythrocytes were used for the determination of IgG antibodies or the quantification of IgM, IgA, or IgE specific isotypes. This procedure allows the simple and reproducible collection of objective results. Moreover, it permits a reduction in cut-off values and direct interpretation of results with automatic conversion of scores into titer, units, index, or into any other scale appropriate for standardization purposes.

Agglutination Tests↗
PubMed1995

Rapid detection of toxoplasmic nucleic acid by enzyme-linked immunofiltration-assay after membrane transfer.

We report the use of enzyme-linked immunofiltration-assay (ELIFA) for rapid detection of Toxoplasma gondii DNA after transfer to nitrocellulose or nylon membranes. Saturation, specific labeling with a nonradioactive oligonucleotide probe and washing steps are included in an active filtration process, which is controled by microcomputer regulating reagent flow. This method provides excellent specificity, reproducibility and repeatability. Recycling in a closed circuit or by reversing the direction of flow provides the advantage of reducing the required volume of costly reagents (e.g. probes). ELIFA does not require lengthy membrane manipulation, and hybridization as well as stringency and revelation steps can be automated. The procedure can be carried out in less than 2 h, which is a major time saving compared to conventional solid-phase molecular hybridization techniques.

Animals↗
PubMed1995

Value of specific immunoglobulin A detection by two immunocapture assays in the diagnosis of toxoplasmosis.

The diagnosis of Toxoplasma gondii infection is currently based on immunological tests, but tests for IgG and IgM antibodies alone are often insufficient to assess the risk of active disease, especially during pregnancy and in immunodeficient subjects. The supplementary diagnostic value of testing for antitoxoplasmic IgA in cases of acute, chronic, congenital and reactivated toxoplasmosis, relative to classical immunological tests, was evaluated using two immunocapture tests, one based on tachyzoite agglutination and the other on an immunoenzymatic complex recognizing the membrane protein P30 of Toxoplasma gondii. A total of 4,541 sera from 395 uninfected subjects, 468 immunized subjects with chronic infection, 117 subjects with acute infection and 403 children, 103 of whom had congenital toxoplasmosis, was tested. Specific IgA tests were negative in the nonimmune population, but tests for this immunoglobulin subtype became positive very rapidly during primary infection, and IgA disappeared more rapidly than IgM. In the children infected in utero, specific IgA was detected more frequently than IgM. In contrast, in a population of HIV-seropositive subjects with clinical toxoplasmosis, tests for IgA were poorly sensitive. The two tests for specific IgA produced similar results, except in the early stages of primary infection, in which immunoenzymatic testing for anti-P30 IgA was less sensitive than the agglutination method.

Agglutination Tests↗
PubMed1995

[A little known cause of persistent fever and granulomatous hepatitis in children: cat scratch disease].

BACKGROUND: Extensive hepatic and splenic involvement in cat-scratch disease has rarely been reported. CASE REPORT: A 2 1/2 year-old boy suffered for 2 weeks from high-grade fever, abdominal pain and alteration of his general condition. Ultrasonography revealed multiple hypoechogenic nodules in liver and spleen. The CT scan also showed hypodense lesions. An open liver biopsy was performed 5 weeks after the onset of illness. Histopathology of a resected nodule demonstrated neutrophilic granulomatous inflammation with central abscess formation. Recent cat exposure, suppurated epitrochlear lymph node 15 days before admission were also consistent with cat-scratch disease which was confirmed by elevated anti-Rochalimaea antibody titers. Follow-up showed complete resolution of all hepatic and splenic lesions within 6 months and emergence of splenic calcifications. CONCLUSION: Cat-scratch disease should be considered in the diagnosis of fever of unknown origin and hepatosplenic abscesses in children.

Cat-Scratch Disease↗