Molecular biology of prion propagation.

The occurrence of new variant Creutzfeldt-Jakob disease and the experimental confirmation that it is caused by the same prion strain as BSE has dramatically highlighted the need for a precise understanding of the molecular basis of prion propagation. The molecular basis of prion-strain diversity, previously a major challenge to the protein-only model, is now becoming clearer. The conformational change thought to be central to prion propagation, from a predominantly alpha-helical fold to one predominantly comprising beta-structure, can now be reproduced in vitro, and the ability of beta-PrP to form fibrillar aggregates provides a plausible molecular mechanism for prion propagation.

An evaluation of 'rapid review' as a method of quality control of cervical smears using the AxioHOME microscope.

One method of quality control which has recently been recommended by professional bodies in the UK is the 'rapid review' method. This involves the microscopic 30 s review of all negative cervical smears with the intention of flagging potential missed abnormalities. Although it has been suggested that rapid review is better than 10% random rescreening of negative smears, the efficiency and efficacy of this method of quality control have not been thoroughly evaluated.

Analysis of ribosomal and alphoid repetitive DNA by fiber-FISH.

We have used fluorescence in situ hybridization to extended DNA fibers (fiber-FISH) to analyse the alpha-satellite and rDNA arrays on a human chromosome 22. The rDNA could be seen as a string of signals spanning about 430 kb. The bulk of the alphoid DNA was found in a single large array of about 2.

Identification, prevalence and aspects of molecular biology of hepatitis G virus.

Hepatitis G virus (HGV) is a newly identified member of the Flaviviridae family. The positive-sense RNA genome of the virus contains a single open reading frame that encodes the viral polyprotein. Its genomic organization is similar to that of the hepatitis C virus (HCV) with which it has only 25% homology at the nucleotide level.

Thalidomide reduces tumour necrosis factor-alpha production by human alveolar macrophages.

Overexuberant production of tumour necrosis factor-alpha (TNF-alpha) by macrophages and other cells is thought to contribute to the development of permanent lung damage in many inflammatory conditions. There is a need for an agent, without the side-effects of corticosteroids, which can reduce the production of TNF-alpha by macrophages activated by disease. This study evaluated the effect of thalidomide on lipopolysaccharide (LPS)-induced TNF-alpha production by human alveolar macrophages obtained from patients with tuberculosis and a group of other diseases associated with macrophage activation.

No evidence of antibody to human foamy virus in widespread human populations.

The first human foamy virus (HFV) to be described was isolated from nasopharyngeal carcinoma tissue from a Kenyan patient. Early seroepidemiology concluded that there was a significant infection rate, particularly among Africans. Awareness of foamy viruses as potential vectors has stimulated interest in the natural seroprevalence of HFV infection.

Stable episomal maintenance of yeast artificial chromosomes in human cells.

Plasmids carrying the Epstein-Barr virus origin of plasmid replication (oriP) have been shown to replicate autonomously in latently infected human cells (J. Yates, N. Warren, D.

Qualitative research in health care: II. A structured review and evaluation of studies.

A hand search of the original papers in seven medical journals over 5 years was conducted in order to identify those reporting qualitative research. A total of 210 papers were initially identified, of which 70 used qualitative methods of both data collection and analysis. These papers were evaluated by the researchers using a checklist which specified the criteria of good practice.

Calcium channel blockers in the dock: innocent or guilty?

Several studies have recently been published which have raised doubts over the long-term safety of calcium channel blockers (CCB). These have included retrospective case control studies in hypertension and meta-analyses of small scale studies in unstable angina and myocardial infarction (MI). Most of the reports were primarily concerned with the use of the short acting dihydropyridine nifedipine.

Decision making in the neonatal intensive care environment.

Consideration as to whether withdrawal of intensive care support might be a more appropriate line of action than to continue with full intensive care has become a part of the life and death decision making process undertaken in neonatal intensive care units. After outlining the moral objectives of delivery of health care, the arguments for taking quality of life and its various components into account during these deliberations are presented. The circumstances in which the appropriateness of continuing care should be considered are highlighted and the care options presented.