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Biomedical subjects

A Allard

Publications and source records attributed to A Allard.

24 records · Page 2Linked to original sources

Enteric adenoviruses.

The 41 serotypes of human adenoviruses are classified into six subgenera (A-F) with different tropisms. Enteric infections are caused in children by serotypes Ad40 and Ad41 of subgenus F. Serotypes Ad40 and Ad41 transform embryonic cells but cannot induce tumours in newborn hamsters. They differ from all other (established) human adenoviruses by being unable to replicate in conventional cell cultures. Ad40 and Ad41 grow in 293 cells (human embryonic kidney cells immortalized by transfection with the E1A, E1B regions of Ad5). In spite of the difficulty of isolating Ad40 and Ad41 they can be directly identified in stools by enzyme-linked immunosorbent assay (ELISA) and solid-phase immuno-electron microscopy. The amount of viral DNA in stool preparations is sufficient for identification by DNA restriction or dot-blot analysis. Adenoviruses have been associated with 7-17% of cases of diarrhoea in children. Ad40 and Ad41 cause diarrhoea throughout the year. Clinical features are watery stools, vomiting and moderately elevated temperature; respiratory symptoms are infrequent. The diarrhoea is protracted (mean 8.6 and 12.2 days for Ad40 and Ad41 respectively). Children with rotavirus diarrhoea vomited more frequently and had a higher temperature and diarrhoea of shorter duration. The impact of enteric adenoviruses in the aetiology of diarrhoea world-wide is not known but is accessible to investigation.

Adenoviridae Infections↗

Prevalence of occupational asthma in spray painters exposed to several types of isocyanates, including polymethylene polyphenylisocyanate.

The prevalence of occupational asthma was assessed in four paint shops of a large assembly plant where 51 employees were exposed to several types of isocyanates, including polymethylene polyphenylisocyanate (PPI). Three employees were first referred by their physician for asthma symptoms. A questionnaire was administered to the other 48 employees. Seven of these were suspected of having work-related asthma. Airway hyperexcitability to inhaled histamine was demonstrated in these ten subjects (three referred and seven screened). The diagnosis of occupational asthma was confirmed in six subjects (three referred and three screened) through specific inhalation challenges in the laboratory to a paint system component containing PPI. Thus, the prevalence of occupational asthma was 11.8% in these paint shops using several types of isocyanates, including PPI.

Adult↗

Detection of adenoviruses in stool specimens by nucleic acid spot hybridization.

Nucleic acid hybridization was used for the detection of adenovirus DNA in stool specimens, and the results were compared with those obtained by a radioimmunoassay (RIA) for adenovirus hexon antigen. DNA from 40 specimens, 18 of which were positive by RIA, were spotted onto nitrocellulose filters and analyzed by hybridization using radioactively labeled adenovirus-2 DNA or a cloned DNA fragment from enteric adenovirus-41 as probes. With the adenovirus-2 DNA probe, 15 of the 18 RIA-positive specimens were also positive in the hybridization assay, and one of the RIA negative specimens was also scored as positive. The cloned adenovirus-41 fragment gave a positive signal with five specimens, all of which were also detected with the adenovirus-2 DNA probe. The results show that hybridization is an alternative method for detection of adenovirus in stool specimens. The sensitivity of the assay is comparable to that of the RIA.

Acute Disease↗