Study of prophylaxis by didecyl dimethyl ammonium chloride against herpes simplex virus infection in nude mice.

Primary or recurrent viral infections, especially by herpetoviridae, with viraemias--after organ transplants, for example--are a serious medical problem which can affect the prognosis for survival. An experimental protocol for the prevention of infection by a herpes simplex virus type 1 was applied to Nude mice infected via inhalation. It suggests the possibility of appreciably limiting viral infection by the parenteral use of didecyl dimethyl ammonium chloride. The results are encouraging and could lead to further experimental studies to prove the efficiency of this molecule whose level of toxicity can be disassociated from its antiviral action to limit the infections by other enveloped viruses.

Virus isolation, polymerase chain reaction and in vitro antibody production for the diagnosis of pediatric human immunodeficiency virus infection.

Viral culture (VC), polymerase chain reaction (PCR) and in vitro antibody production (IVAP) by peripheral blood mononuclear cells were compared for the early diagnosis of HIV-1 infection in 46 infants born to HIV-1 seropositive mothers. The ten children considered infected on the basis of clinical signs and persistence of anti-HIV-1 antibodies had at least one positive viral culture and seven were always positive in both PCR and IVAP tests. PCR and IVAP tests were occasionally negative in three infected children. Among 30 healthy children who became seronegative and were always negative for viral culture, 22 (73.3%) were also repeatedly negative in PCR and IVAP. We report 6 cases of children classified as P2A at the term of this study but who had lost anti-HIV-1 antibodies. They presented at least one positive viral culture and occasional positive PCR and/or IVAP results. The results indicate that the combination of viral culture, PCR and IVAP tests improves the early diagnosis of pediatric HIV infection.

Detection of Mycoplasma pneumoniae in clinical samples from pediatric patients by polymerase chain reaction.

The polymerase chain reaction (PCR) technique was used to detect Mycoplasma pneumoniae DNA in clinical samples (nasopharyngeal aspirations or bronchoalveolar lavages) obtained from 100 children, 1 month to 16 years old. PCR allowed the detection of M. pneumoniae DNA from 20 out of the 100 patients studied. In 16 cases, PCR positivity was associated with acute respiratory symptomatology. For five PCR-positive patients, a positive culture or a serological response evidenced acute M. pneumoniae infections. A lack of antibody response was observed particularly with immunocompromised children and infants less than 12 months old. The amount of M. pneumoniae DNA in the PCR was estimated in a semiquantitative way by comparison of its hybridization signal with those obtained for 100, 10, and 1 color-changing unit (CCU) of the M. pneumoniae FH strain. Small amounts (less than or equal to 10(2) CCU/ml) of M. pneumoniae were found in samples from asymptomatic patients, while larger amounts (greater than or equal to 10(2) to greater than or equal to 10(4) CCU/ml) were found for 8 out of 10 patients with acute pneumonia.

[Viral diarrheas]. / Diarrhées virales.

It is now well known that several viruses are responsible for acute diarrhoea or gastroenteritis in both children and adults. These viruses are difficult to identify since most of them cannot be isolated by stool cultures on cells. The reality of proven reinfection by some of these organisms is not always clearly understood, even though the existence of several serotypes in the same group (notably rotavirus) can be blamed, and this explains why vaccines are difficult to develop.

Dot ELISA for direct detection of BK virus in urine samples.

The dot ELISA technique was applied for direct detection of BK virus in clinical urine samples. The assay was performed on nitrocellulose paper dotted with the polyethylene glycol precipitated urine samples free of cellular debris. BK virus was detected with an anti-BK virus monoclonal antibody, and the complex was visualized by immunoperoxidase staining. Positive reaction appeared as well-defined dark blue spots. Of the 110 urine samples examined, 31 were positive in the dot ELISA and 79 proved negative. Comparing with the IIF results, the dot ELISA had a 88.46% of sensibility and 90.4% of specificity, and the results agreed completely in 99 samples. The simple dot ELISA technique can be recommended for detection of BK virus excretion in routinary diagnostic.

[Anatomical and microbiological study of the conditions for baboon-man liver xenograft]. / Etude anatomique et microbiologique des conditions d'une xénogreffe hépatique babouin-homme.

This work assesses the anatomical and infectious problems of heteroplastic transplantation from a baboon to a man. The study was carried out with 30 baboons of the primatology laboratory of the CNRS. The aspects studied included the anatomic structure and the biology of the liver, the microbial and parasitic population, and the serological features. Out of these 30 animals, 8 were selected as potential donors.

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.

Reactogenicity and immunogenicity of rotavirus WC3 vaccine in 5-12 month old infants.

Rotavirus is a major cause of acute gastroenteritis in infants worldwide and there is need for an effective vaccine. Rotavirus Wistar calf 3 (WC3) is a strain of bovine origin attenuated by 12 passages in cell culture. A lyophilized candidate vaccine containing 1 x 10(7) PFU of WC3 has been developed. An oral dose was given to 25 French infants 5-12-months old (mean age 8.6 months). No diarrhoea was observed within 2 weeks after vaccination. Unexplained vomiting was reported once and isolated fever greater than 37.8 degrees C was reported 3 times during the first week. One month later, a neutralizing antibody response to serotypes tested was shown in 88% of cases, with heterotypic responses to human serotype 3 (SA11 strain) in 72% and to type 1 (WA strain) in 48%. The percentage of immune response was similar whether the infant had antibody prior to immunization or not, but a booster effect was observed in children who had pre-immunization rotavirus antibodies. Considering these promising results, efficacy trials are in the planning in different parts of the world.

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.

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.

[Bronchiolitis caused by respiratory syncytial virus in very young infants and transmitted maternal antibodies]. / Bronchiolites à virus respiratoire syncytial chez le tout jeune enfant et anticorps maternels transmis.

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.

Follow-up of subjects with isolated and persistent anti-core (anti-p24 or anti-p17) antibodies to HIV.

Systematic screening of blood donations by enzyme-linked immunosorbent assay (ELISA) for HIV antibodies carries a false-positive rate: the sera involved react in Western blot to core antigens (p24 or p17) but reactivity to envelope is absent. We studied 22 subjects with persistent and isolated anti-core reactivities; 75 HIV seropositive patients were controls. The epidemiological data and the follow-up and biological tests performed in these two populations argue that donors with persistent and isolated anti-core antibodies are not seroconverting for HIV. We conclude: (1) that verification of all anti-HIV ELISA-positive sera by Western blot is essential and that the presence of at least once anti-envelope (gp120 or gp41) antibody is indispensable for the diagnosis of HIV infection; (2) that the solitary anti-p24 or anti-p17 bands observed on Western blot are false-positive. There is no evidence that donors with such reactivities are HIV-infected.

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.

Evaluation of three assays on alveolar lavage fluid in the diagnosis of cytomegalovirus pneumonitis after bone marrow transplantation.

Cytologic examination, immunofluorescence assays, and cultures for virus were compared prospectively in the detection of cytomegalovirus (CMV) in cells obtained by 41 bronchoalveolar lavages (BALs) from 30 bone marrow transplant recipients with pneumonia. No evidence of CMV was found in 21 BALs. Viral inclusions, positive immunologic assays, and positive cultures were found in 14, 15, and 18 BALs, respectively. Cytological and immunologic results were closely related except in one BAL. In five BALs, a positive culture for virus was the sole criterion noted for diagnosis of CMV. The patients with both cytologically and immunologically positive results were more likely to die with or from respiratory failure (P less than .05), diffuse interstitial patterns (P less than .01), and severe acute graft-vs.-host disease (P less than .02) than were the patients without any criterion for diagnosis of CMV. The discrepancies with the previously reported data, the interpretation of the three diagnostic procedures, and the ability of BAL to diagnose CMV pneumonia are discussed.