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J Sarfati

Publications and source records attributed to J Sarfati.

34 records · Page 2Linked to original sources
PubMed1996

Prospective sandwich enzyme-linked immunosorbent assay for serum galactomannan: early predictive value and clinical use in invasive aspergillosis.

BACKGROUND: The delay between the onset of invasive aspergillosis and the start of antifungal therapy is crucial for the patient's recovery. Early diagnosis is difficult in cancer patients through lack of precocious specific signs. We have investigated the clinical usefulness of circulating Aspergillus antigen monitoring in pediatric hematology patients with a new sensitive sandwich enzyme-linked immunosorbent assay. METHODS: A prospective study was conducted by assessing circulating galactomannan levels in high risk patients. Thirty-seven patients studied during an 18-month period were evaluated twice weekly during neutropenic phases with the sandwich enzyme-linked immunosorbent assay for serum Aspergillus galactomannan. RESULTS: Twelve patients had one or more episodes of positive circulating galactomannan detection, 10 of whom developed presumptive invasive aspergillosis. The clinical and radiologic signs occurred at a mean of 13.4 days (range, 0 to 48) after circulating galactomannan detection and reversed in 6 patients treated with amphotericin B at the same time circulating galactomannan detection became negative. Reappearance of circulating galactomannan was observed during subsequent neutropenic periods in 3 patients. CONCLUSIONS: The detection of galactomannan at concentrations as low as 1 ng/ml can be useful for the early initiation of antifungal therapy and monitoring treatment in clinically documented lung aspergillosis. This technique coupled with chest computed tomography could help to restrict the need of invasive diagnostic procedures in fragile patients.

Adolescent↗
PubMed1996

Genotypic characterization of sequential Aspergillus fumigatus isolates from patients with cystic fibrosis.

Twenty-three sequential Aspergillus fumigatus sputum isolates, which had been collected over a period of 2 years, from two patients with cystic fibrosis were genotyped by random amplified polymorphic DNA PCR and restriction fragment length polymorphism analysis. In patient B, one genotype was predominantly present in the sputum samples, while in the other patient up to nine different genotypes were identified. This study suggests that different patterns of colonization with A.fumigatus exist in patients with cystic fibrosis.

Aspergillus fumigatus↗
PubMed1996

[Course of benign dysphonia in children].

The study of a population of 45 children by examining their speech before and after puberty showed that at puberty there was no subjective complaint in 56% as far as nodules were concerned, there were normal laryngeal appearances in 80% of males compared with only 21% in females after microsurgery. This may lead to the conclusion that nodules in girls persist into adulthood, whereas those in boys tend not to persist, especially if they have had the benefit of speech therapy.

Adolescent↗
PubMed1995

A new sensitive sandwich enzyme-linked immunosorbent assay to detect galactofuran in patients with invasive aspergillosis.

A double-direct sandwich enzyme-linked immunosorbent assay that uses a rat anti-galactomannan monoclonal antibody as the acceptor and detector antibody was designed. This immunoassay, which detects less than 1 ng of galactomannan per ml, was assessed in a retrospective study with samples from patients with invasive aspergillosis. Serum is more appropriate than urine for use in the search for circulating galactomannan. Antigenemia does not have a transient character. Galactomannan can be detected at least 39 days before the death of the patients.

Adolescent↗
PubMed1994

Use of DNA moderately repetitive sequence to type Aspergillus fumigatus isolates from aspergilloma patients.

Polymorphism of forty-seven sequential clinical isolates from 3 patients with an aspergilloma was analyzed. DNA from each isolate was digested with EcoRI and hybridized in Southern blots with a 32P-labeled nonribosomal DNA repetitive sequence. Most isolates from each patient displayed the same hybridization pattern. Southern blot patterns obtained with DNA repetitive sequences can be used to type clinical isolates of Aspergillus fumigatus and have shown that aspergilloma patients are most probably infected by a single strain.

Aspergillosis↗
PubMed1994

Chemical and immunological characterization of the extracellular galactomannan of Aspergillus fumigatus.

The galactomannan (GM) produced extracellularly by Aspergillus fumigatus has been purified by a double sequential hydrazine-nitrous acid treatment of the ethanol precipitate of the culture filtrate. Nuclear magnetic resonance and gas-liquid chromatography-mass spectrometry analysis have been performed on intact GM, acid-hydrolyzed GM, and oligomers resulting from the acetolysis of the acid-hydrolyzed GM. Results show that A. fumigatus GM is composed of a linear mannan core with an alpha-(1-2)-linked mannotetraose repeating unit attached via alpha-(1-6) linkage. Side chains composed of an average of 4 to 5 beta-(1-5)-galactofuranose units are linked to C-6 and C-3 positions of alpha-(1-2)-linked mannose units of the mannan. The immunoreactivity of GM and HCl-hydrolyzed GM was studied by use of human sera from aspergillosis patients and an antigalactofuran monoclonal antibody. The alpha-(1-2) (1-6)-mannan core is not antigenic. The immunogenic galactofuran is found amongst several exocellular glycoproteins. According to a direct enzyme-linked immunosorbent assay with GM as the detector antigen, only 26% of the serum samples from aspergilloma patients (all positive by immunodiffusion assays) give optical density values superior to a cutoff estimated as the mean +/- 3 standard deviations of values obtained with control sera.

Antibodies, Fungal↗
PubMed1994

Molecular epidemiology of nosocomial invasive aspergillosis.

Moderately repeated DNA sequences were used to fingerprint strains of Aspergillus fumigatus isolated from patients with invasive aspergillosis and their hospital environment. Most strains sampled from the environment displayed different Southern blot hybridization patterns. A temporal survey of air contaminants showed that some strains can persist in the same environment for at least 6 months. Patients with invasive aspergillosis were infected by a single strain. In two patients, a nosocomial origin of infection was suggested.

Aspergillosis↗
PubMed1994

[Tools, progress and questions in the molecular study of Aspergillus fumigatus and invasive aspergillosis].

Development of A. fumigatus in the host tissues is due to the intrinsic biological characteristics of this fungus and to the impairment of the cellular defence reactions of the host. However, even today the understanding of the factors governing the infectivity of A. fumigatus remains very limited. For example, the cellular mechanisms involved in the killing of A. fumigatus are still not elucidated. The cellular site(s) of infection and the role of the different lung epithelia in the establishment of the fungus are unknown. No specific fungal virulence factors have been identified until now. Molecular biology techniques are powerful tools to investigate the pathogenesis of invasive aspergillosis. Recent developments in the study of this mycosis are presented in this review.

Aspergillosis↗
PubMed1993

Virulence of alkaline protease-deficient mutants of Aspergillus fumigatus.

The gene encoding the secreted alkaline protease, a suspected virulence factor of Aspergillus fumigatus, was inactivated by gene disruption. The disruption was performed by transformation of a pathogenic strain of the fungus with a linear DNA fragment carrying the gene from which the central part was replaced by the selectable Escherichia coli hygromycin B dominant resistance marker. Two transformants were shown to produce no alkaline protease. Restriction fragment analysis of the DNA of these two transformants was consistent for chromosomal integration of the disrupted gene by homologous recombination. Both isogenic alkaline protease-producing and non-producing A. fumigatus strains invaded lung tissues, causing comparable mortality in immunosuppressed mice. A significant residual proteolytic activity observed in alkaline protease non-producing strain cultures could play a role in the invasion of the tissues by the fungus.

Animals↗
PubMed1993

Detection of galactomannan and the 18 kDa antigen from Aspergillus fumigatus in serum and urine from cattle with systemic aspergillosis.

Serum and urine samples from cattle with experimental and spontaneous systemic mycotic infections were tested for the presence of galactomannan and the 18 kDa antigen from Aspergillus fumigatus by an inhibition ELISA and immunoblotting, respectively. High levels of galactomannan (approximately 80 ng/ml.) were detected in serum from two of three calves experimentally infected with A. fumigatus. In two out of three cows with spontaneous acquired aspergillosis a similar amount of galactomannan was detected. Galactomannan was not found in serum samples of 20 cows which aborted due to either experimental or spontaneous placental aspergillosis. Twenty-four of forty urine samples from normal cattle reacted positively in the ELISA, consequently, the assay was not applicable on bovine urine. The 18 kDa antigen from A. fumigatus was detected in the urine from one calf out of three calves experimentally infected with aspergillosis and in the urine from one cow with spontaneous aspergillosis. It is concluded that detection of galactomannan in serum and the 18 kDa antigen in urine may be used as an aid for the diagnosis of disseminated bovine aspergillosis with the exception of placental and probably gastrointestinal localization.

Abortion, Veterinary↗
PubMed1993

Cell wall antigens in Aspergillus fumigatus.

The Aspergillus cell wall contains most of the antigens secreted by the fungus during its active in vitro or in vivo growth. These antigens, which bind to the IgE and IgG of allergic and aspergilloma patients or are secreted in the biological fluids of patients with invasive aspergillosis, are of primary importance in the diagnosis of aspergillosis. Located at the interface between host and pathogen cells, the fungal cell wall plays a major role during fungal invasion. It contains several surface receptors involved in adhesion of the fungus to host proteins and cells. Some of the wall antigens are also directly involved in the colonization of the host tissues by the fungus. Very few of these putative virulence factors have been purified until now. A 33-kDa alkaline protease of the subtilisin family can hydrolyze several extracellular matrix proteins such as collagen, fibrinogen, elastin. However, gene disruption experiments have shown that protease-deficient mutants are still able to infect mice. An 18-kDa antigen, which has been detected in the urine of patients with invasive aspergillosis, is present in vivo in the lung of mice infected with A. fumigatus. It has a ribonuclease activity that cleaves a single phosphodiester bond in a highly conserved region of the ribosomal RNA. Its role in the virulence of A. fumigatus has not been demonstrated until now. Biochemical and molecular characterization of the wall antigenic aggressins should be pursued.

Allergens↗
PubMed1992

Rat monoclonal antibodies against Aspergillus galactomannan.

Monoclonal antibodies (MAbs) against Aspergillus fumigatus galactomannan were produced in rats. Seven of them, EB-A1 through EB-A7, were characterized in more detail. They were all immunoglobulin M antibodies, reacting in an indirect enzyme-linked immunosorbent assay with purified A. fumigatus galactomannan, with avidity constants of between 2 x 10(9) and 5 x 10(9)/M. Enzyme-linked immunosorbent assay inhibition experiments with modified galactomannan and synthetic oligomers of beta (1----5)galactofuranose demonstrated that the MAbs bound to an epitope located on the beta(1----5)galactofuranose-containing side chains of the galactomannan molecule. An identical or similar epitope also seemed to be present in other fungi. Immunofluorescence and immunoelectron microscopy experiments with EB-A2 revealed the presence of the antigen in the fungal wall and inside the cell. Immunoblotting experiments demonstrated that the epitope recognized by the MAbs was a common oligosaccharide moiety of a wide range of intracellular and extracellular glycoproteins in A. fumigatus. The characteristics of the MAbs justify their use in the diagnosis of invasive aspergillosis by antigen detection.

Animals↗
PubMed1989

[Vocal retraining of teachers].

A population of 90 teachers referred for vocal disorders is analyzed. In one third of the cases, no morphological anomaly was noted in the larynx. Pseudocysts and nodules were found in another third. Polyps (5 cases) were found in P.E. teachers, 8 epidermoid cysts and 3 sulcusglottidis were noted. For each professional category and for each type of lesion, the re-education of teachers presents predominant tendencies, but should remain the result of an individual assessment for each case.

Female↗
PubMedDate not supplied

Route of infections in bovine aspergillosis.

Repeated DNA sequences were used to fingerprint strains of Aspergillus fumigatus isolated from a cow with disseminated systemic aspergillosis, cows with single aspergillosis lesions, calves aborted due to bovine aspergillosis, mothers of those calves, and cattle without aspergillosis. The analysis of the Southern blot hybridization patterns obtained suggested that: (i) the portal of entry of aspergillosis in cattle is the gastrointestinal tract, and (ii) infection of aborted calves is due to maternally derived strains. Cattle from the same farm slaughtered on the same day harbour the same strain, suggesting a contamination from feed material.

Animals↗
PubMedDate not supplied

Antigens of Aspergillus fumigatus produced in vivo.

Immunoblots of extracts from kidneys of mice infected intravenously with Aspergillus fumigatus were probed with human sera from patients with aspergilloma. A limited number of antigens were detected with molecular masses of 31, 36, 56, 84, 88 and 200 kDa. These antigens can be clustered into two classes: (i) galactomannan and/or galactofuran-containing glycoproteins; and (ii) antigenic proteins (31, 36 and 88 kDa) exempt of the galactofuran epitope. Antigens belonging to this second class were also produced in vitro but were not the major proteins expressed by A. fumigatus in a glucose-asparagin medium.

Animals↗