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Biomedical subjects

A Garbarg-Chenon

Publications and source records attributed to A Garbarg-Chenon.

52 records · Page 3Linked to original sources

Restriction endonuclease analysis of human cytomegalovirus isolated in immunocompromised patients.

Cytomegalovirus is frequently isolated from immunosuppressed patients or from patients with acquired immunodeficiency syndrome. Twelve patients were studied for several months. In 7 patients more than 1 Cytomegalovirus was isolated; in one of these patients three viruses were isolated, two of them show small differences in their migration pattern and the third seems to be a different strain after restriction analysis of CMV genome. This could reflect variation in the genome of the CMV virus as it has been already shown for viruses from other families in immunocompromised patients and shows the occurrence of multiple strains infection in a single patient.

Acquired Immunodeficiency Syndrome↗

Characterization of a plasmid coding for resistance to broad-spectrum cephalosporins in Salmonella typhimurium.

Five strains of Salmonella typhimurium isolated from faeces of infants hospitalized at Trousseau Hospital in Paris have been found to be resistant to third-generation cephalosporins. This resistance is by a transferable plasmid-mediated mechanism. The beta-lactamase gene which encodes for an enzyme similar to SHV-2 has been cloned into plasmid pBR322 and expressed in Escherichia coli RR1.

Cefotaxime↗

[Bronchiolitis caused by respiratory syncytial virus in very young infants and transmitted maternal antibodies].

The study with an Enzyme Linked Immunosorbent Assay of the sera of 57 infants aged less than 9 weeks and developing a bronchiolitis, argues for the absence of a protective role for the maternally transmitted anti-respiratory syncytial virus (RSV) IgG and for the existence of a positive relationship between these antibodies levels - which are not neutralizing - and the severity of RSV bronchiolitis.

Antibodies, Viral↗

Epidemiologic and genomic study of rotavirus strains infecting young children and calves in the same rural environment.

The epidemiological profile of rotavirus infection in young calves and young children form the same rural environment in France was studied during autumn-winter 1983-1984. Viruses were isolated from calves on each farm and were identified by their electropherotype for 8 out of the 9 farms under study. Among 13 children regularly checked on 9 farms for 25 weeks, 7 were found to be rotavirus positive. Nevertheless, no transfer of virus between child and bovine was documented by the electropherotype migration. In the case of the calves, the predominance of the Ib IIa IIIe IVa electropherotype at 5 of the 9 farms is similar to the epidemiological situation observed among newborn in some maternity wards.

Animals↗

Simplified enzyme-linked immunosorbent assay for specific antibodies to respiratory syncytial virus.

A simplified and reliable enzyme-linked immunosorbent assay (ELISA) was applied to the detection of serum antibodies against respiratory syncytial virus (RSV). RSV-infected cells were fixed and dried on 96-well microtiter plates and kept at 4 degrees C. The titers of reference sera were determined by endpoint dilution. A linear relation was found between the titers and the logarithm of absorbance values of sera diluted to 1:1,000 (r = 0.93, P less than 0.001). Measurement of RSV antibodies was done by using a single serum dilution (1:1,000) in conjunction with a standard curve. A strong correlation was found between complement fixation and ELISA results (r = 0.89, P less than 0.001). In addition, the ELISA method exhibited higher titers and a greater sensitivity than did complement fixation, although the applicability of the assay is limited with positive serum samples of low titer.

Animals↗

Serological characterization of human reassortant rotaviruses.

We analyzed the serological properties of two human wild-type cell culture-adapted rotaviruses (strains 308 and 46) and of 308 X 46 reassortants which were previously obtained and genetically characterized. Strain 308, exhibiting a so-called long RNA pattern, was found to belong to human rotavirus subgroup II, serotype 1, whereas strain 46, exhibiting a so-called short RNA pattern, represented subgroup I, serotype 2. Among the 308 X 46 reassortants we analyzed, two belonged to subgroup II, serotype 1, and exhibited short RNA patterns. This showed that the correlation observed between human subgroups I and II rotaviruses and the short and long electrophoretic patterns is not supported by any molecular basis (i.e., gene segment 10 or 11 was not involved in the subgroup specificity).

Antibodies, Monoclonal↗

Study of genetic reassortment between two human rotaviruses.

Eight different human rotavirus strains were adapted to replicate in cell culture. In vitro, rotavirus genetic reassortment has been performed between two virus strains, one with a long pattern of segmented genomic RNAs and the other with a short pattern in the electrophoretic mobility of genomic RNAs. This genetic reassortment was detectable despite the lack of selective markers in the parental strains. Moreover, some of the reassorted virus exhibited mixed RNA patterns containing extra genomic RNAs resembling those found in clinical specimens. These viruses with mixed RNA band patterns could segregate their supplementary segments after successive passages in cell culture. Finally it has been shown that classification of genomic segments in long and short electropherotypes should not only be based on their relative size but also by their ability to reassort with the genetically equivalent segment.

Cell Line↗

DNA hybridization for detection of human cytomegalovirus in bronchoalveolar lavage and pharynx biopsy.

A simplified hybridization procedure was used for detection of cytomegalovirus (CMV) in human specimens. The probe was a 32P-labelled cloned DNA fragment of CMV strain AD169. This probe did not hybridize to DNA from uninfected cells or other herpesviruses (herpes simplex virus, Epstein-Barr virus). Specific hybridization was obtained with unselected bronchoalveolar lavage specimens, but the sensitivity of the test (33%) was lower than that of culture (80%) and immunofluorescence (60%) assays which are routinely performed in our laboratory. The detection procedure was also carried out with pharynx biopsy specimens which had been kept frozen at -70 degrees C. CMV DNA was detected in 14% of tumour specimens and only in 1.7% of control specimens (p less than 0.05). The indications of DNA hybridization for CMV diagnosis are discussed.

Bronchoalveolar Lavage Fluid↗

BK virus (BKV) detection in urine specimens of immunocompromised patients: comparison between the DNA-DNA hybridization assay, the immunofluorescence test and the dot enzyme immunoassay.

Three methods used for the detection of BK virus in urine specimens, the indirect immunofluorescence test, the dot enzyme immunoassay and the DNA-DNA hybridization assay, were compared by testing specimens from 49 immunocompromised patients. All three assays were effective in detecting BK virus. The technical advantage of each of them was discussed. The immunofluorescence test was found to be the simplest one to perform; the DNA-DNA hybridization assay displayed exquisite sensitivity; and the easy reading of the dot enzyme immunoassay did not require the specialized training inherent to immunofluorescence assays. The dot enzyme immunoassay might therefore be the most practical method for screening urine specimens of immunocompromised patients, especially when the sediment is poor in cells. Conversely, the indirect immunofluorescence test might be the method of choice for checking patients with haemorragic cystitis whose urine samples usually contain large amounts of cells.

BK Virus↗