Quality assurance and risk reduction guidelines

Cervical cancer continues to be a major cause of death in women worldwide. The major problem facing most women is the unavailability of screening Pap tests in poor and underdeveloped countries. While rates of cancer deaths have decreased 60-80% in developed countries since the Pap test became available, the accuracy of Paps was challenged recently. In order to instill public confidence and promote optimal patient care, measures to improve the quality of the entire screening process should be undertaken. Continuous quality improvement processes are more appropriate than traditional quality assurance monitors. Although no standards can be defined that are applicable to all laboratory settings and nations, this document provides current views on universal quality procedures and risk reduction. Procedure/policy manuals, workload assessment, hierarchic/peer review, discrepancy analysis, rescreening studies and cytohistologic correlation are examples of universally applicable quality tools. The variability in practices in different parts of the world is also discussed.     

Developmental instability and inbreeding in natural bird populations exposed to different levels of habitat disturbance

As habitat disturbance and inbreeding increasingly stress natural populations, ecologists are in urgent need of simple estimators to measure their impact. It has been argued that developmental instability (DI) could be such a measure. Observed associations between DI and environmental or genetic stress, however, are largely inconsistent. We here test whether an interaction between habitat disturbance and inbreeding could, at least partly, explain these discordant patterns. We therefore studied individual estimates of fluctuating asymmetry (FA) and of inbreeding in three populations of the critically endangered Taita thrush that are differentially exposed to habitat disturbance following severe forest fragmentation. As predicted, the relationship between DI and inbreeding was pronounced under high levels of disturbance, but weak or nonexistent under less disturbed conditions. Examining this relationship with mean d², an allelic distance estimator assumed to reflect ancestral inbreeding, did not reveal any significant trend, hence suggesting that inbreeding effects in the Taita thrush are fairly recent.     

Genetic variability and gene flow in the globally, critically-endangered Taita thrush

Analysis of 155 individuals with seven polymorphicmicrosatellite DNA markers showed significant genetic differentiationbetween the only three remaining subpopulations of the globally,critically-endangered Taita thrush. Small, recently-disturbedsubpopulations such as studied here may violate the assumptions ofmutation-drift and gene flow-drift equilibrium inherent to mostpopulation genetic tools that estimate gene flow. We thereforeidentified putative dispersers using two recently-developed assignmenttests based on individual genotypes. Previous-generation and currentmigration rates between any two subpopulations were estimated at one andzero individuals per generation, respectively. Strong congruence withnon-genetic estimates of between-fragment dispersal provided indirectevidence for the accuracy of the assignment test. From a conservationperspective, the available demographic and genetic data suggest asubstantial threat to the long-term survival of at least the smallestsubpopulation.     

Luteinising hormone,follicle stimulating hormone and gonadotropin releasing hormone immunoreactivity in two insects: Locusta migratoria migratoroides R&F and Sarcophaga bullata (Parker)

Summary

Materials immunologically related to luteinising hormone (LH), follicle stimulating hormone (FSH) and the gonadotropin releasing hormone (GnRH) were localised in cerebral tissue of Locusta migratoria and Sarcophaga bullata by means of the peroxidase-antiperoxidase method. Several polyclonal and a monoclonal antisera were used. From the third larval instar a positive reaction was observed in cells located in several parts of the brain. Each antiserum reacted with a constant number of well defined cells and nerve fibers. No differences between sexes were observed.     

CYFIP dependent actin remodeling controls specific aspects of Drosophila eye morphogenesis

Cell rearrangements shape organs and organisms using molecular pathways and cellular processes that are still poorly understood. Here we investigate the role of the Actin cytoskeleton in the formation of the Drosophila compound eye, which requires extensive remodeling and coordination between different cell types. We show that CYFIP/Sra-1, a member of the WAVE/SCAR complex and regulator of Actin remodeling, controls specific aspects of eye architecture: rhabdomere extension, rhabdomere terminal web organization, adherens junctions, retina depth and basement membrane integrity. We demonstrate that some phenotypes manifest independently, due to defects in different cell types. Mutations in WAVE/SCAR and in ARP2/3 complex subunits but not in WASP, another major regulator of Actin nucleation, phenocopy CYFIP defects. Thus, the CYFIP-SCAR-ARP2/3 pathway orchestrates specific tissue remodeling processes.     

Genetic transformation with untranslatable coat protein gene of <Emphasis Type="Italic">sugarcane yellow leaf virus</Emphasis> reduces virus titers in sugarcane

Sugarcane yellow leaf syndrome, characterized by a yellowing of the leaf midrib followed by leaf necrosis and growth suppression, is caused by sugarcane yellow leaf virus (SCYLV). We produced SCYLV-resistant transgenic sugarcane from a susceptible cultivar (H62-4671) and determined the amount of virus present following inoculation. The transgenic plants were produced through biolistic bombardment of cell cultures with an untranslatable coat protein gene. Presence of the transgene in regenerated plants was confirmed using PCR and Southern blot analysis. The transgenic lines were inoculated by viruliferous aphids and the level of SCYLV in the plants was determined. Six out of nine transgenic lines had at least 10³-fold lower virus titer than the non-transformed, susceptible parent line. This resistance level, as measured by virus titer and symptom development, was similar to that of a resistant cultivar (H78-4153). The selected SCYLV-resistant transgenic sugarcane lines will be available for integration of the resistance gene into other commercial cultivars and for quantification of viral effects on yield.     

A new real-time PCR method to overcome significant quantitative inaccuracy due to slight amplification inhibition

Background  

Real-time PCR analysis is a sensitive DNA quantification technique that has recently gained considerable attention in biotechnology, microbiology and molecular diagnostics. Although, the cycle-threshold (Ct) method is the present "gold standard", it is far from being a standard assay. Uniform reaction efficiency among samples is the most important assumption of this method. Nevertheless, some authors have reported that it may not be correct and a slight PCR efficiency decrease of about 4% could result in an error of up to 400% using the Ct method. This reaction efficiency decrease may be caused by inhibiting agents used during nucleic acid extraction or copurified from the biological sample.