Measurement properties of the EQ-5D across four major geriatric conditions: Findings from TOPICS-MDS

Background: As populations age, chronic geriatric conditions linked to progressive organ failure jeopardize health-related quality of life (HRQoL). Thus, this research assessed the validity and applicability of the EQ-5D (a common HRQoL instrument) across four major chronic geriatric conditions: hearing issues, joint damage, urinary incontinence, or dizziness with falls. Methods: The study sample comprised 25,637 community-dwelling persons aged 65 years and older residing in the Netherlands (Data source: TOPICS-MDS, www.topics-mds.eu ). Floor and ceiling effects were examined. To assess convergent validity, random effects meta-correlations (Spearman's rho) were derived between individual EQ-5D domains and related survey items. To further examine construct validity, the association between sociodemographic characteristics and EQ-5D summary scores were assessed using linear mixed models. Outcomes were compared to the overall study population as well as a 'healthy' subgroup reporting no major chronic conditions. Results: Whereas ceiling effects were observed in the overall study population and the 'healthy' subgroup, such was not the case in the geriatric condition subgroups. The majority of hypotheses regarding correlations between survey items and sociodemographic associations were supported. EQ-5D summary scores were lower in respondents who were older, female, widowed/single, lower educated, and living alone. Increasing co-morbidity had a clear negative effect on EQ-5D scores. Conclusion: This study supported the construct validity of the EQ-5D across four major geriatric conditions. For older persons who are generally healthy, i.e. reporting few to no chronic conditions, the EQ-5D confers poor discriminative ability due to ceiling effects. Although the overall dataset initially suggested poor discriminative ability for the EQ-5D, such was not the case within subgroups presenting with major geriatric conditions

Size does matter: Cre-mediated somatic deletion efficiency depends on the distance between the target lox-sites

Cre/lox recombination in vivo has become an important tool to induce chromosomal rearrangements like deletions. Using a combination of Ds transposition and Cre/lox recombination in two independent experiments on chromosomes 6 and 7 of tomato, two sets of somatic deletions up to a size of 200 kb were obtained. The efficiency of somatic deletion decreased with increasing deletion size. The largest germinally transmitted deletion had a size of only 55 kb. The results show that Cre-mediated deletion in somatic cells is less efficient when the lox sites are separated over larger distances. A further drop of the deletion efficiency after germinal transmission of the larger deletions can be explained by the probable loss of genes that are of vital importance to gametophyte function. Plasmid rescue of an 8.4 kb circularised deleted DNA showed that the Cre-mediated deletion takes place in tomato as expected. Since the circular Cre-deleted DNA could only be PCR amplified in plant cells where the deletion was not complete, the double-stranded DNA circle is assumed to be instable

The effector protein Avr2 of the xylem-colonizing fungus Fusarium oxysporum activates the tomato resistance protein I-2 intracellularly

To promote host colonization, many plant pathogens secrete effector proteins that either suppress or counteract host defences. However, when these effectors are recognized by the host's innate immune system, they trigger resistance rather than promoting virulence. Effectors are therefore key molecules in determining disease susceptibility or resistance. We show here that Avr2, secreted by the vascular wilt fungus Fusarium oxysporum f. sp. lycopersici (Fol), shows both activities: it is required for full virulence in a susceptible host and also triggers resistance in tomato plants carrying the resistance gene I-2. Point mutations in AVR2, causing single amino acid changes, are associated with I-2-breakingFol strains. These point mutations prevent recognition by I-2, both in tomato and when both genes are co-expressed in leaves of Nicotiana benthamiana. Fol strains carrying the Avr2 variants are equally virulent, showing that virulence and avirulence functions can be uncoupled. Although Avr2 is secreted into the xylem sap when Fol colonizes tomato, the Avr2 protein can be recognized intracellularly by I-2, implying uptake by host cells

Cre recombinase expression can result in phenotypic aberrations in plants

The cre recombinase gene was stably introduced and expressed in tomato, petunia and Nicotiana tabacum. Some plants expressing the cre gene driven by a CaMV 35S promoter displayed growth retardation and a distinct pattern of chlorosis in their leaves. Although no direct relation can be proven between the phenotype and cre expression, aberrant phenotypes always co-segregate with the transgene, which strongly suggests a correlation. The severity of the phenotype does not correlate with the level of steady-state mRNA in mature leaves, but with the timing of cre expression during organogenesis. The early onset of cre expression in tomato is correlated with a more severe phenotype and with higher germinal transmission frequencies of site-specific deletions. No aberrant phenotype was observed when a tissue-specific phaseolin promoter was used to drive the cre gene. The data suggest that for the application of recombinases in plants, expression is best limited to specific tissues and a short time frame.[12pt] Abbreviations: bar, the phosphinotricin acetyltransferase gene; CAM, chloramphenicol resistance gene; Ds 5 & Ds 3, borders of the Ds transposable element from maize forming a functional transposable element that embodies the interjacent DNA; gus, the -glucoronidase gene; gus-int, the gus gene interrupted by a plant intron; hpt, the hygromycin phosphotransferase gene; nptII, the neomycin phosphotransferase gene; ORI, bacterial origin for plasmid replication in Escherichia coli of plasmid p15A Cre recombinase - lox P - petunia - site-specific recombination - tobacco - tomato - toxicit