Basis for high-affinity ethylene binding by the ethylene receptor ETR1 of Arabidopsis.

The gaseous hormone ethylene is perceived in plants by membrane-bound receptors, the best studied of these being ETR1 from Arabidopsis. Ethylene receptors can mediate a response to ethylene concentrations at less than one part per billion; however, the mechanistic basis for such high-affinity ligand binding has remained elusive. Here we identify an Asp residue within the ETR1 transmembrane domain that plays a critical role in ethylene binding. Site-directed mutation of the Asp to Asn results in a functional receptor that has a reduced affinity for ethylene, but still mediates ethylene responses in planta. The Asp residue is highly conserved among ethylene receptor-like proteins in plants and bacteria, but Asn variants exist, pointing to the physiological relevance of modulating ethylene-binding kinetics. Our results also support a bifunctional role for the Asp residue in forming a polar bridge to a conserved Lys residue in the receptor to mediate changes in signaling output. We propose a new structural model for the mechanism of ethylene binding and signal transduction, one with similarities to that found in a mammalian olfactory receptor.

The cost-effectiveness of antenatal and postnatal education and support interventions for women aimed at promoting breastfeeding in the UK.

BACKGROUND: Breastfeeding is associated with health benefits to mothers and babies and cost-savings to the health service. Breastfeeding rates in the UK are low for various reasons including cultural barriers, inadequate support to initiate and sustain breastfeeding, lack of information, or choice not to breastfeed. Education and support interventions have been developed aiming at promoting breastfeeding rates. The objective of this study was to assess the cost-effectiveness of such interventions for women, initiated antenatally or in the first 8 weeks postnatally, aiming at improving breastfeeding rates, in the UK. METHODS: A decision-analytic model was constructed to compare costs and quality-adjusted life-years (QALYs) of a breastfeeding intervention from the perspective of health and personal social services in England. Data on intervention effectiveness and the benefits of breastfeeding were derived from systematic reviews. Other model input parameters were obtained from published sources, supplemented by expert opinion. RESULTS: The incremental cost-effectiveness ratio (ICER) of the modelled intervention added on standard care versus standard care was £51,946/QALY, suggesting that the intervention is not cost-effective under National Institute for Health and Care Excellence (NICE) criteria in England. Sensitivity analysis suggested that the cost-effectiveness of the intervention improved as its effectiveness increased and intervention cost decreased. At the base-case effect (increase in breastfeeding rates 16-26 weeks after birth by 19%), the intervention was cost-effective (<£20,000/QALY) if its cost per woman receiving the intervention became ≈£40-£45. At the base-case cost (£84), the intervention was cost-effective if it increased breastfeeding rates by at least 35-40%. CONCLUSIONS: Available breastfeeding interventions do not appear to be cost-effective under NICE criteria in England. Future breastfeeding interventions need to have higher effectiveness or lower cost compared with currently available interventions in order to become cost-effective. Public health and other societal interventions that protect, promote and support breastfeeding may be key in improving breastfeeding rates in the UK.

How Do Older Adults Decide to Visit the Emergency Department? Patient and Caregiver Perspectives.

Seniors account for a high number of emergency department (ED) visits, yet little is known about how they decide to visit the ED. This paper reports on the results of surveys completed by 264 seniors who visited the ED and their caregivers and interviews with a subset (N = 51) of survey respondents, aimed at understanding how they decide to visit the ED. Although older adults rely on others to help them decide whether to visit the ED, only a small proportion consult healthcare providers in doing so. Opportunities exist for enhancing seniors' decision-making process regarding ED visits and access to community-based healthcare to avoid ED visits.

WITHDRAWN: Interventions for nausea and vomiting in early pregnancy.

BACKGROUND: Nausea and vomiting are the most common symptoms experienced in early pregnancy, with nausea affecting between 70 and 85% of women. About half of pregnant women experience vomiting. OBJECTIVES: To assess the effects of different methods of treating nausea and vomiting in early pregnancy. SEARCH STRATEGY: We searched the Cochrane Pregnancy and Childbirth Group trials register (December 2002) and the Cochrane Central Register of Controlled Trials (The Cochrane Library, Issue 4, 2002). SELECTION CRITERIA: Randomised trials of any treatment for nausea and/or vomiting in early pregnancy. DATA COLLECTION AND ANALYSIS: Two reviewers assessed the trial quality and extracted the data independently. MAIN RESULTS: Twenty-eight trials met the inclusion criteria. For milder degrees of nausea and vomiting, 21 trials were included. These trials were of variable quality. Nausea treatments were: different antihistamine medications, vitamin B6 (pyridoxine), the combination tablet Debendox (Bendectin), P6 acupressure and ginger. For hyperemesis gravidarum, seven trials were identified testing treatments with oral ginger root extract, oral or injected corticosteroids or injected adrenocorticotropic hormone (ACTH), intravenous diazepam and acupuncture. Based on 12 trials, there was an overall reduction in nausea from anti-emetic medication (odds ratio 0.16, 95% confidence interval 0.08 to 0.33). AUTHORS' CONCLUSIONS: Anti-emetic medication appears to reduce the frequency of nausea in early pregnancy. There is some evidence of adverse effects, but there is very little information on effects on fetal outcomes from randomised controlled trials. Of newer treatments, pyridoxine (vitamin B6) appears to be more effective in reducing the severity of nausea. The results from trials of P6 acupressure are equivocal. No trials of treatments for hyperemesis gravidarum show any evidence of benefit. Evidence from observational studies suggests no evidence of teratogenicity from any of these treatments.

WITHDRAWN: Antihistamines versus aspirin for itching in late pregnancy.

BACKGROUND: While not common, itching in pregnancy (not due to liver disease) can be distressing. OBJECTIVES: The objective of this review was to assess the effects of treatment for itching in late pregnancy. SEARCH STRATEGY: We searched the Cochrane Pregnancy and Childbirth Group trials register (January 2007). SELECTION CRITERIA: Randomised trials of treatments for itching in women in late pregnancy with normal liver function. DATA COLLECTION AND ANALYSIS: Two review authors independently assessed trial quality and extracted data. MAIN RESULTS: One study of 38 women was included. This was a small crossover trial, using alternate allocation. The trial compared a histamine, chlorpheniramine, with aspirin. Aspirin was more effective than chlorpheniramine in relieving itching (odds ratio 2.39, 95% confidence interval 1.25 to 4.57). However, chlorpheniramine was more effective than aspirin when a rash was present. AUTHORS' CONCLUSIONS: Aspirin appears to be more effective than chlorpheniramine for relief of itching in pregnancy when no rash is present. If there is a rash, chlorpheniramine may be more effective.

Characterization of microRNA expression levels and their biological correlates in human cancer cell lines.

MicroRNAs are small noncoding RNAs that function by regulating target gene expression posttranscriptionally. They play a critical role in developmental and physiologic processes and are implicated in the pathogenesis of several human diseases including cancer. We examined the expression profiles of 241 human microRNAs in normal tissues and the NCI-60 panel of human tumor-derived cell lines. To quantify microRNA expression, we employed a highly sensitive technique that uses stem-loop primers for reverse transcription followed by real-time PCR. Most microRNAs were expressed at lower levels in tumor-derived cell lines compared with the corresponding normal tissue. Agglomerative hierarchical clustering analysis of microRNA expression revealed four groups among the NCI-60 cell lines consisting of hematologic, colon, central nervous system, and melanoma tumor-derived cell lines clustered in a manner that reflected their tissue of origin. We identified specific subsets of microRNAs that provide candidate molecular signatures characteristic of the tumor-derived cell lines belonging to these four clusters. We also identified specific microRNA expression patterns that correlated with the proliferation indices of the NCI-60 cell lines, and we developed evidence for the identification of specific microRNAs as candidate oncogenes and tumor suppressor genes in different tumor types. Our results provide evidence that microRNA expression patterns may mark specific biological characteristics of tumors and/or mediate biological activities important for the pathobiology of malignant tumors. These findings call attention to the potential of microRNAs to provide etiologic insights as well as to serve as both diagnostic markers and therapeutic targets for many different tumor types.

Factors for Self-Managing Care Following Older Adults' Discharge from the Emergency Department: A Qualitative Study.

Cette étude avait pour but d'identifier les facteurs qui influent sur la capacité des personnes âgées à prendre en charge leur santé après une consultation au service des urgences (SU). Les questionnaires de l'enquête (n = 380) ont été remplis en SU par des personnes âgées et leurs aidants et visaient à évaluer leur perception de la compréhension de l'information qui leur était fournie. Des entrevues (n = 51) ont été réalisées avec un sous-échantillon de participants au cours des quatre semaines suivant leur consultation au SU et ont examiné les facteurs ayant une incidence sur l'autogestion des problèmes de santé. La perception de la compréhension de l'information reçue en SU (« oui, certainement ¼) était meilleure lors de la consultation au SU (91 %) que lors du suivi (71 %), lorsque 20 % des participants ne comprenaient pas ou n'étaient pas certains qu'ils avaient compris ce qui leur avait été communiqué en SU. Les patients ont rapporté que l'autogestion de leurs problèmes de santé était influencée par: la communication avec le personnel du SU, la compréhension des attentes suivant le congé de l'hôpital, l'état de santé, la disponibilité des aidants et divers facteurs externes. De plus, les soignants ont aussi mentionné l'appui aux soignants et la résistance des patients aux recommandations. L'utilisation de stratégies adaptées aux aînés en SU (p. ex. recommandations écrites, confirmation de la compréhension des recommandations), particulièrement celles liées à l'identification des personnes à risque et de celles nécessitant davantage de soutiens transitoires ou un meilleur accès ou intégration aux ressources disponibles dans la communauté amélioreraient l'autogestion des problèmes de santé suivant les consultations en SU.This study identified factors affecting seniors' ability to self-manage their health following an Emergency Department (ED) visit. Surveys (n = 380) completed by older adults and their caregivers in the ED assessed their understanding of information provided. Interviews (n = 51) completed with a participant subsample up to four weeks post-ED visit examined self-management factors. Perceived understanding of the information ("Yes, definitely") received in the ED was greater at the time of the visit (91%) than at follow-up (71%). Patients reported self-management was influenced by communication with ED staff, understanding of post-discharge expectations and the health condition(s), caregiver availability, and various external factors. Caregivers also identified support for caregivers and patient resistance to recommendations. Senior-friendly strategies (e.g., recommendations in writing, confirmed understanding of recommendations), particularly those related to identifying those at risk and needing greater transitional supports, and greater access to and integration with community supports could enhance post-ED self-management.

Drinking-water arsenic exposure modulates gene expression in human lymphocytes from a U.S. population.

BACKGROUND: Arsenic exposure impairs development and can lead to cancer, cardiovascular disease, and diabetes. The mechanism underlying these effects remains unknown. Primarily because of geologic sources of contamination, drinking-water arsenic levels are above the current recommended maximum contaminant level of 10 microg/L in the northeastern, western, and north central regions of the United States. OBJECTIVES: We investigated the effects of arsenic exposure, defined by internal biomarkers at levels relevant to the United States and similarly exposed populations, on gene expression. METHODS: We conducted separate Affymetrix microarray-based genomewide analyses of expression patterns. Peripheral blood lymphocyte samples from 21 controls interviewed (1999-2002) as part of a case-control study in New Hampshire were selected based on high- versus low-level arsenic exposure levels. RESULTS: The biologic functions of the transcripts that showed statistically significant abundance differences between high- and low-arsenic exposure groups included an overrepresentation of genes involved in defense response, immune function, cell growth, apoptosis, regulation of cell cycle, T-cell receptor signaling pathway, and diabetes. Notably, the high-arsenic exposure group exhibited higher levels of several killer cell immunoglobulin-like receptors that inhibit natural killer cell activity. CONCLUSIONS: These findings define biologic changes that occur with chronic arsenic exposure in humans and provide leads and potential targets for understanding and monitoring the pathogenesis of arsenic-induced diseases.

MicroRNAs and other tiny endogenous RNAs in C. elegans.

BACKGROUND: MicroRNAs (miRNAs) are small noncoding RNAs that are processed from hairpin precursor transcripts by Dicer. miRNAs probably inhibit translation of mRNAs via imprecise antisense base-pairing. Small interfering RNAs (siRNAs) are similar in size to miRNAs, but they recognize targets by precise complementarity and elicit RNA-mediated interference (RNAi). We employed cDNA sequencing and comparative genomics to identify additional C. elegans small RNAs with properties similar to miRNAs and siRNAs. RESULTS: We found three broad classes of small RNAs in C. elegans: (1) 21 new miRNA genes (we estimate that C. elegans contains approximately 100 distinct miRNA genes, about 30% of which are conserved in vertebrates; (2), 33 distinct members of a class of tiny noncoding RNA (tncRNA) genes with transcripts that are similar in length to miRNAs (approximately 20-21 nt) and that are in some cases developmentally regulated but are apparently not processed from a miRNA-like hairpin precursor and are not phylogenetically conserved; (3) more than 700 distinct small antisense RNAs, about 20 nt long, that are precisely complementary to protein coding regions of more than 500 different genes and therefore seem to be endogenous siRNAs. CONCLUSIONS: The presence of diverse endogenous siRNAs in normal worms suggests ongoing, genome-wide gene silencing by RNAi. miRNAs and tncRNAs are not predicted to form complete Watson-Crick hybrids with any C. elegans RNA target, and so they are likely to regulate the activity of other genes by non-RNAi mechanisms. These results suggest that diverse modes of small RNA-mediated gene regulation are deployed in normal worms.

Translating evidence into practice: the case of dementia guidelines in specialized geriatric services.

This paper describes a process of identifying best practice guidelines for non-pharmacological management for individuals with dementia and disseminating them to a group of frontline practitioners in specialized geriatric services. Our dissemination plan involved early participation of practitioners, development of a chart summarizing five guidelines showing commonalities, contrasts, and gaps in the guidelines, and their interpretation, colour-coded for the strength of the evidence on which they were based. Two sequential workshops were held in which recommendations for action were developed. Outcomes of the process included a resource manual, a network of practitioners, and action recommendations based upon survey data. An early follow-up evaluation showed increased adoption of guidelines.

Captive Care, Raising, and Breeding of the Veiled Chameleon (Chamaeleo calyptratus).

Squamate reptiles comprise approximately one-third of all living amniotes. In most of these species, it is difficult to study gastrulation and neurulation because the embryos are at a late stage of development at the time of oviposition. This is not the case, however, in veiled chameleons (Chamaeleo calyptratus), which are increasingly being used as a model organism to study these and other developmental and evolutionary phenomena. Originating from the Arabian Peninsula, veiled chameleons are arboreal specialists that possess extensive morphological specializations for climbing. They naturally inhabit semitropical habitats, but they also have an almost 30-yr history of being bred in captivity. Veiled chameleons breed readily and do not require a period of cooling to induce the reproductive cycle, and females can produce ∼45-90 eggs multiple times per year. Thus, compared with other reptiles, relatively few animals are needed to maintain a productive breeding colony. Herein, we present the conditions, equipment, and techniques required for proper husbandry and breeding of veiled chameleons within a laboratory environment.

The Veiled Chameleon (Chamaeleo calyptratus Duméril and Duméril 1851): A Model for Studying Reptile Body Plan Development and Evolution.

Vertebrate model organisms have facilitated the discovery and exploration of morphogenetic events and developmental pathways that underpin normal and pathological embryological events. In contrast to amniotes such as Mus musculus (Mammalia) and Gallus gallus (Aves), our understanding of early patterning and developmental events in reptiles (particularly nonavians) remains weak. Squamate reptiles (lizards, snakes, and amphisbaenians) comprise approximately one-third of all living amniotes. But studies of early squamate development have been limited because, in most members of this lineage, embryo development at the time of oviposition is very advanced (limb bud stages and older). In many cases, squamates give birth to fully developed offspring. However, in the veiled chameleon (Chamaeleo calyptratus), embryos have progressed only to a primitive pregastrula stage at the time of oviposition. Furthermore, the body plan of the veiled chameleon is highly specialized for climbing in an arboreal environment. It possesses an entire suite of skeletal and soft anatomical modifications, including cranioskeletal ornamentation, lingual anatomy and biomechanics for projection, autopodial clefting for grasping, adaptations for rapid integumental color changes, a prehensile tail with a lack of caudal autotomy, the loss of the tympanum in the middle ear, and the acquisition of turreted eyes. Thus, C. calyptratus is an important model organism for studying the role of ecological niche specialization, as well as genetic and morphological evolution within an adaptive framework. More importantly, this species is easily bred in captivity, with only a small colony (<10 individuals) needed to obtain hundreds of embryos every year.

Psychometric properties of the modified RESIDE physical activity questionnaire among low-income overweight women.

OBJECTIVES: This study explored the criterion-related validity and test-retest reliability of the modified RESIDential Environment physical activity questionnaire and whether the instrument's validity varied by body mass index, education, race/ethnicity, or employment status. DESIGN: Validation study using baseline data collected for randomized trial of a weight loss intervention. METHODS: Participants recruited from health departments wore an ActiGraph accelerometer and self-reported non-occupational walking, moderate and vigorous physical activity on the modified RESIDential Environment questionnaire. We assessed validity (n=152) using Spearman correlation coefficients, and reliability (n=57) using intraclass correlation coefficients. RESULTS: When compared to steps, moderate physical activity, and bouts of moderate/vigorous physical activity measured by accelerometer, these questionnaire measures showed fair evidence for validity: recreational walking (Spearman correlation coefficients 0.23-0.36), total walking (Spearman correlation coefficients 0.24-0.37), and total moderate physical activity (Spearman correlation coefficients 0.18-0.36). Correlations for self-reported walking and moderate physical activity were higher among unemployed participants and women with lower body mass indices. Generally no other variability in the validity of the instrument was found. Evidence for reliability of RESIDential Environment measures of recreational walking, total walking, and total moderate physical activity was substantial (intraclass correlation coefficients 0.56-0.68). CONCLUSIONS: Evidence for questionnaire validity and reliability varied by activity domain and was strongest for walking measures. The questionnaire may capture physical activity less accurately among women with higher body mass indices and employed participants. Capturing occupational activity, specifically walking at work, may improve questionnaire validity.

Nucleic acid separations utilizing immobilized metal affinity chromatography.

Immobilized metal affinity chromatography (IMAC) is widely used for protein purification, e.g., in the isolation of proteins bearing the well-known hexahistidine affinity tag. We report that IMAC matrixes can also adsorb single-stranded nucleic acids through metal ion interactions with aromatic base nitrogens and propose that metal affinity technologies may find widespread application in nucleic acid technology. Oligonucleotide duplexes, plasmid, and genomic DNA show low IMAC binding affinity, while RNA and single-stranded oligonucleotides bind strongly to matrixes such as Cu(II) iminodiacetic acid (IDA) agarose. The affinity of yeast RNA for IDA-chelated metal ions decreases in the following order: Cu(II), Ni(II), Zn(II), and Co(II). Adsorption isotherms for 20-mer oligonucleotide homopolymers show that purines are strongly favored over pyrimidines and that double-stranded duplexes are not bound. IMAC columns have been used to purify plasmid DNA from E. coli alkaline lysates, to purify a ribozyme, to remove primers and imperfect products from PCR reactions, and to separate 20-mer oligonucleotide duplexes containing centered single-base mismatches. Potential further applications include SNP scoring, hybridization assays, and the isolation of polyadenylated messenger RNA.

Breathing air from protein foam.

Protein foams can be used to extinguish fires. If foams are to be used to extinguish fires where people are present, such as in high-rise buildings or ships, then a method for allowing people to breathe in a foam-filled environment is needed. It is proposed that the air, used to create the foam be used for breathing. A canister that will break incoming air-filled foam has been designed for attachment to a standard gas mask, in order to provide breathable air to a trapped person. Preliminary results for the modified mask indicate feasibility of breathing air from air-filled protein foam.