Agreement between people with aphasia and their proxies on health-related quality of life after stroke, using the Greek SAQOL-39g

Health related quality of life (HRQL) measures are increasingly used to evaluate stroke interventions. People with severe aphasia after stroke may be unable to self-report on such measures, necessitating the use of proxy respondents. This study explored the level of agreement between people with aphasia and their proxies on the Greek Stroke and Aphasia Quality of Life Scale-39 generic version (SAQOL-39g) and whether this agreement was influenced by proxy levels of depression and carer strain. Methods: Par-ticipants were people with aphasia (PWA) who were over six months post-stroke and medically stable. Proxies were nominated by the PWA and had to see them at least twice a week. PWA completed the Frenchay Aphasia Screening Test and the Greek SAQOL-39g. Proxies completed the Greek SAQOL-39g proxy version, the General Health Questionnaire-12 and the Caregiver Strain Index. Results: 23 pairs of people with aphasia and their proxies took part. Proxies rated people with aphasia as more severely af-fected than they rated themselves. The difference was significant for the overall scale and the physical and communication domains (p < 0.05); yet the bias introduced by these differences was small to moderate, with effect sizes ranging from 0.15 to 0.47. The strength of the agreement between people with aphasia and proxies was excellent for the overall scale and all three domains (ICC = 0.79 - 0.97). The level of agreement was not associated with carer strain or emotional distress. We conclude that clinicians and re-searchers can use proxy ratings to evaluate the quality of life of people with severe aphasia but need to be aware of trends in proxy reporting and take these into account when interpreting data

The absence or presence of a lytic coliphage affects the response of Escherichia coli to heat, chlorine, or UV exposure

Disinfection aims at maximal inactivation of target organisms and the sustainable suppression of their regrowth. Whereas many disinfection efforts achieve efficient inactivation when the effect is measured directly after treatment, there are questions about the sustainability of this effect. One aspect is that the treated bacteria might recover and regain the ability to grow. In an environmental context, another question is how amenable surviving bacteria are to predation by omnipresent bacteriophages. Provisional data suggested that bacteria when subjected to sublethal heat stress might develop a phage-resistant phenotype. The result made us wonder about the susceptibility to phage-mediated lysis for bacteria exposed to a gradient of chlorine and UV-LED disinfection strengths. Whereas bacteria exposed to low sublethal chlorine doses still underwent phage-mediated lysis, the critical chlorine Ct of 0.5 mg min/L eliminated this susceptibility and induced phage resistance in the cells that survived treatment. In the case of UV, even the smallest tested dose of 2.8 mJ/cm2 abolished phage lysis leading to direct regrowth. Results suggest that bacteria surviving disinfection might have higher environmental survival chances directly after treatment compared to non-treated cells. A reason could possibly lie in their compromised metabolism that is essential for phage replication

Effect of temperature on bacteriophage-mediated lysis efficiency with a special emphasis on bacterial temperature history

Despite the great potential of phages as biocontrol agents, there is much uncertainty about the environmental factors influencing lysis efficiency. In this study we investigated the effect of temperature using three distinct lytic E. coli phages that were isolated from a single environmental water sample. All three were identified as dsDNA phages belonging to the Myoviridae family. Whereas the optimal growth temperature of E. coli is well known to be 37 ˚C and exposure of phages (prior to mixing with bacteria) to temperatures between 4 and 37˚C did not affect their infectivity, plaque sizes and numbers greatly decreased with increasing incubation temperature (20˚C, 30˚C, 37˚C) of the phage-host mix. At 37˚C, no visible plaques were observed. Results suggest that temperature sensitivity of the phage-host interaction is distinct from the temperature susceptibility of the two players and corroborate previous reports that highest lysis rates are obtained at temperatures approximate with ambient conditions of the phage environment. Infectivity was however found not only to depend on the incubation temperature of the phage-host mix, but also on the bacterial temperature history. Moreover, exposure of bacteria to heat stress prior to phage challenge resulted in a phage-resistant phenotype raising the question whether bacterial pathogens shed from warm-blooded hosts might be less susceptible to phages adapted to environmental temperature conditions

The absence or presence of a lytic coliphage affects the response of Escherichia coli to heat, chlorine, or UV exposure

Disinfection aims at maximal inactivation of target organisms and the sustainable suppression of their regrowth. Whereas many disinfection efforts achieve efficient inactivation when the effect is measured directly after treatment, there are questions about the sustainability of this effect. One aspect is that the treated bacteria might recover and regain the ability to grow. In an environmental context, another question is how amenable surviving bacteria are to predation by omnipresent bacteriophages. Provisional data suggested that bacteria when subjected to sublethal heat stress might develop a phage-resistant phenotype. The result made us wonder about the susceptibility to phage-mediated lysis for bacteria exposed to a gradient of chlorine and UV-LED disinfection strengths. Whereas bacteria exposed to low sublethal chlorine doses still underwent phage-mediated lysis, the critical chlorine Ct of 0.5 mg min/L eliminated this susceptibility and induced phage resistance in the cells that survived treatment. In the case of UV, even the smallest tested dose of 2.8 mJ/cm2 abolished phage lysis leading to direct regrowth. Results suggest that bacteria surviving disinfection might have higher environmental survival chances directly after treatment compared to non-treated cells. A reason could possibly lie in their compromised metabolism that is essential for phage replication

Y-chromosome phylogeographic analysis of the Greek-Cypriot population reveals elements consistent with Neolithic and Bronze Age settlements

International audienceBackground: The archeological record indicates that the permanent settlement of Cyprus began with pioneering agriculturalists circa 11,000 years before present, (ca. 11,000 y BP). Subsequent colonization events followed, some recognized regionally. Here, we assess the Y-chromosome structure of Cyprus in context to regional populations and correlate it to phases of prehistoric colonization. Results: Analysis of haplotypes from 574 samples showed that island-wide substructure was barely significant in a spatial analysis of molecular variance (SAMOVA). However, analyses of molecular variance (AMOVA) of haplogroups using 92 binary markers genotyped in 629 Cypriots revealed that the proportion of variance among the districts was irregularly distributed. Principal component analysis (PCA) revealed potential genetic associations of Greek-Cypriots with neighbor populations. Contrasting haplogroups in the PCA were used as surrogates of parental populations. Admixture analyses suggested that the majority of G2a-P15 and R1b-M269 components were contributed by Anatolia and Levant sources, respectively, while Greece Balkans supplied the majority of E-V13 and J2a-M67. Haplotype-based expansion times were at historical levels suggestive of recent demography. Conclusions: Analyses of Cypriot haplogroup data are consistent with two stages of prehistoric settlement. E-V13 and E-M34 are widespread, and PCA suggests sourcing them to the Balkans and Levant/Anatolia, respectively. The persistent pre-Greek component is represented by elements of G2-U5(xL30) haplogroups: U5*, PF3147, and L293. J2b-M205 may contribute also to the pre-Greek strata. The majority of R1b-Z2105 lineages occur in both the westernmost and easternmost districts. Distinctively, sub-haplogroup R1b-M589 occurs only in the east. The absence of R1b-M589 lineages in Crete and the Balkans and the presence in Asia Minor are compatible with Late Bronze Age influences from Anatolia rather than from Mycenaean Greeks

Lysis performance of bacteriophages with different plaque sizes and comparison of lysis kinetics after simultaneous and sequential phage addition

Background: Although bacteriophages see a revival for specifically removing undesired bacteria, there is still much uncertainty about how to achieve the most rapid and long-lasting clearance. Materials and Methods: This study investigated the lysis kinetics of three distinct environmental coliphages, reproducibly forming different plaque sizes (big, medium, and small). Lysis performance by individual phages was compared with the one obtained after simultaneous or sequential addition of all three phages. Kinetics was monitored by density absorbance or by flow cytometry, with the latter having the advantage of providing higher sensitivity. Results: Plaque size happened to correlate with lysis kinetics in liquid suspensions, with phages producing big (phage B), medium (phage M), and small (phage S) plaques showing maximal bacterial clearance under the chosen conditions within ∼6, 12, and 18 h, respectively. Use of a phage cocktail (all three phages added simultaneously) resulted in slower initial lysis compared with the fastest lysing phage with the greatest plaque size alone, but it showed longer efficacy in suppression. When adding phages sequentially, overall lysis kinetics could be influenced by administering phages at different time points. The lowest bacterial concentration after 36 h was obtained when administering phages in the sequence S, M, and B although this combination initially took the longest to achieve bacterial clearance. Conclusions: Results support that timing and order of phage addition can modulate strength and duration of bacterial suppression and, thus, influence the overall success of phage treatment

Quality of life after stroke: Evaluation of the Greek SAQOL-39g

Background/Aims: Stroke and aphasia rehabilitation aims to improve people’s quality of life. Yet, scales for measuring health-related quality of life in stroke typically exclude people with aphasia. They are also primarily available in English. An exception is the Stroke and Aphasia Quality of Life scale (SAQOL-39g). This scale has been tested with people with aphasia; it has been adapted for use in many countries including Greece. The aim of this study was to examine the psychometric properties of the Greek SAQOL-39g. Methods: An interview-based psychometric study was carried out. Participants completed: receptive sub-tests of Frenchay Aphasia Screening Test, Greek SAQOL-39g, General Health Questionnaire-12, Frenchay Activities Index, Montreal Cognitive Assessment and Barthel Index. Results: 86 people took part; 26 provided test-retest reliability data. The Greek SAQOL-39g demonstrated excellent acceptability (minimal missing data; no floor/ceiling effects), test-retest reliability (ICC= 0.96 scale, 0.83-0.99 domains) and internal consistency (Cronbach’s alpha 0.96 scale, 0.92-0.96 domains). There was strong evidence for convergent (r=0.53-0.80 scale; 0.54-0.89 domains) and discriminant validity (r=0.52 scale; 0.04-0.48 domains). Conclusion: The Greek SAQOL-39g is a valid and reliable scale. It is a promising measure for use in stroke and aphasia treatment prioritization, outcome measurement and service evaluation

Structural Study of Heterogeneous Biological Samples by Cryoelectron Microscopy and Image Processing

In living organisms, biological macromolecules are intrinsically flexible and naturally exist in multiple conformations. Modern electron microscopy, especially at liquid nitrogen temperatures (cryo-EM), is able to visualise biocomplexes in nearly native conditions and in multiple conformational states. The advances made during the last decade in electronic technology and software development have led to the revelation of structural variations in complexes and also improved the resolution of EM structures. Nowadays, structural studies based on single particle analysis (SPA) suggests several approaches for the separation of different conformational states and therefore disclosure of the mechanisms for functioning of complexes. The task of resolving different states requires the examination of large datasets, sophisticated programs, and significant computing power. Some methods are based on analysis of two-dimensional images, while others are based on three-dimensional studies. In this review, we describe the basic principles implemented in the various techniques that are currently used in the analysis of structural conformations and provide some examples of successful applications of these methods in structural studies of biologically significant complexes