RESUMO
An electronic nose (EN) device was used to detect microbial and viral contaminations in a variety of animal cell culture systems. The emission of volatile components from the cultures accumulated in the bioreactor headspace, was sampled and subsequently analysed by the EN device. The EN, which was equipped with an array of 17 chemical gas sensors of varying selectivity towards the sampled volatile molecules, generated response patterns of up to 85 computed signals. Each 15 or 20 min a new gas sample was taken generating a new response pattern. A software evaluation tool visualised the data mainly by using principal component analysis. The EN was first used to detect microbial contaminations in a Chinese hamster ovary (CHO) cell line producing a recombinant human macrophage colony stimulating factor (rhM-CSF). The CHO cell culture was contaminated by Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Candida utilis which all were detected. The response patterns from the CHO cell culture were compared with monoculture references of the microorganisms. Second, contaminations were studied in an Sf-9 insect cell culture producing another recombinant protein (VP2 protein). Contaminants were detected from E. coli, a filamentous fungus and a baculovirus. Third, contamination of a human cell line, HEK-293, infected with E. coli exhibited comparable results. Fourth, bacterial contaminations could also be detected in cultures of a MLV vector producer cell line. Based on the overall experiences in this study it is concluded that the EN method has in a number of cases the potential to be developed into a useful on-line contamination alarm in order to support safety and economical operation for industrial cultivation.
RESUMO
The epidemiology of hepatitis B in hospital personnel was studied by testing of sera from 3,770 employees of the Medical School of Hannover (Hannover, West Germany) for hepatitis B surface antigen (HBsAg) and its corresponding antibody (anti-HBs) by solid-phase radioimmunoassay. An average prevalence of 2.2% for HBsAg and 11.7% for anti-HBs was found. Physicians (18.2%), nurses (20.1%), and members of the cleaning service (26.3%) showed the highest frequencies of HBsAg or anti-HBs carriage. In a study of age- and sex-matched personnel, nurses showed a significantly (P less than 0.01) higher rate of infection than a control group with less exposure to infectious materials. The frequency of HBsAg or anti-HBs was highest in persons associated with dialysis (31.3%), anesthesiology (31.0%), ophthalmology (29.4%, neurosurgery (28.0%), and surgery (24.4%). The rate of infection was significantly higher in surgical departments (24.4%) than in nonsurgical ones (13.3%). Persons who had been nursing patients with hepatitis were significantly (P less than 0.05) more frequently carriers of HBsAg or anti-HBs than a comparable control group.
