Evaluation of human papillomavirus-consensus primers for HPV detection by the polymerase chain reaction.

Cervical cancer is one of the most frequently found cancers in women and appears to have a viral aetiology. Substantial evidence points to the human papillomaviruses (HPV) as the infectious agents and there is considerable interest in identifying and accurately typing the viruses. Since HPVs now comprise more than 100 different HPV types, the polymerase chain reaction (PCR) has been the preferred methodology for virus identification and typing on isolated DNA. In that context, five commonly employed PCR consensus primers have been evaluated for the detection and typing of HPV. The five consensus primer pairs were derived from the consensus sequences of either the L1 and E1 open reading frames. All primers exhibited approximately equal sensitivity, as defined by the ability to detect HPV DNA, on a series of standard HPV DNA-containing preparations. However, the five primer pairs performed differently on 24 HPV-positive and 34 HPV-negative samples obtained from cervical scrapes which had been typed by type-specific PCR for HPV 6/11, 16, 18 and 33. The values for agreement between identification of samples by a HPV type-specific PCR and the consensus primer PCR were 78, 84, 91, 93 and 98%. Three samples, which were positive with only one of the five consensus primer pairs and were negative with the PCR for HPV types 6/11, 16, 18 and 33, contained other HPV sequences or HPV-related sequences as determined by DNA sequence analysis. To our knowledge, this report represents the first extensive comparison of five different consensus primers in a polymerase chain reaction for the detection of HPV. Our results suggest that PCR typing for human papillomaviruses requires more than one consensus primer pair to identify all HPV-infected samples.

Effect of sample holding, cryopreservation, and storage on the human lymphocyte cytogenetic test.

In monitoring occupational populations with the human lymphocyte cytogenetic test, it is not always possible to collect and process matched samples on the same day, even though this would be desirable to control for technical variables. The effects of holding samples for 24 hours at 4 degrees C and 22 degrees C, freezing lymphocytes in dimethylsulfoxide at -180 degrees C, and keeping fixed cells for 6 days at 4 degrees C before slide-making were examined. Final cell count, mitotic index, percentage of cells in first division, percentage of cells with chromosomal aberrations, and sister chromatid exchange per cell were measured in paired cultures. A significant increase in the frequency of cells with chromatid breaks occurred after prolonged fixation, so all other results were obtained from freshly fixed cells. Although holding at 22 degrees C and cryopreservation had significant effects on the mitotic index and entry of lymphocytes into the cell division cycle, the cytogenetic endpoints were not affected by any of the sample manipulations. Thus, samples can be held at 4 degrees C or 22 degrees C for 24 hours, or frozen lymphocytes can be stored for at least a week, without altering the cytogenetic endpoints.

Abilities and requirements profiles: a tool to facilitate reintegration of people with disabilities into employment.

An attempt has been made to construct tools that can be applied for assessment of a disabled individual's residual abilities, and of the requirements of a job for which that person might be considered. The system is based on 63 attributes, which are graded on a 4-point scale. Initial tests revealed 90-95% correspondence between independent assessments. Although more detailed assessment tests are under way, the approach does offer a means for rough preselection of disabled candidates for jobs appropriate to their residual abilities.