Pitfalls of genetic analysis using a doubled-haploid backcrossed to its parent

A population derived from a doubled-haploid backcrossed to its parent has a unique genetic structure, which affects the mapping and genetic analysis of molecular-marker data. In such a cross: (1) repulsion linkages are reduced dramatically and can be detected only in restricted chromosome sections; each repulsion-linkage group represents a section of a chromosome carrying a crossover that occurred in the meiosis that produced the gamete from which the doubled-haploid was derived; (2) the number of coupling-linkage groups observed depends on how many crossovers occurred during the meiosis; the observed size of a linkage group will be only a fraction of a total chromosome if the chromosome carried in the doubled-haploid resulted from crossover exchanges; (3) the size covered by all the observed linkages is only equivalent to the haploid genome; and (4) the ratio of single-dose to multi-dose markers is inflated. These features have not been recognized in previous reports, resulting in misinterpretations in genetic mapping and analysis of the molecular-marker data. The ratio of single- to multi-dose markers has been used inappropriately to distinguish polyploid type.

A 10 year survey of the antimicrobial susceptibility of urinary tract isolates in the UK: the Microbe Base project

Microbe Base is a national computerized database comprising in excess of 1.7 million patient records down-loaded from the laboratory computer systems of 61 participating UK laboratories over 10 years. This paper highlights the antimicrobial susceptibilities of organisms isolated from the urinary tract which comprise around 50% of all isolates in the database. These data may be used to determine trends in antimicrobial susceptibilities; to formulate local antibiotic policies; to compare local with national data and, overall, to assist clinicians in the rational choice of antibiotic therapy and to prevent misuse, or overuse, of antibiotics.

Preliminary evaluation of Cyto-Rich: an improved automated cytology preparation

A new cervical cytology monolayer preparation system called Cyto-Rich was evaluated. Using samples from 557 patients, Cyto-Rich monolayers were compared to matched conventional smears. After conventional smears were prepared and spray fixed, residual exfoliated cells were transferred to preservative fluid. The cell suspensions were gently disaggregated and the epithelial component enriched with gradient centrifugal sedimentation. The batched samples were then placed on the Cyto-Rich work station where slides are automatically prepared and stained. The results demonstrate that Cyto-Rich prepared monolayers are vastly superior to the conventional smears for cell presentation. While the study showed 99% overall concordance. Cyto-Rich improved the detection of low-grade cervical intraepithelial lesions.