Strategies to address participant misrepresentation for eligibility in Web‐based research

Emerging methodological research suggests that the World Wide Web (“Web”) is an appropriate venue for survey data collection, and a promising area for delivering behavioral intervention. However, the use of the Web for research raises concerns regarding sample validity, particularly when the Web is used for recruitment and enrollment. The purpose of this paper is to describe the challenges experienced in two different Web‐based studies in which participant misrepresentation threatened sample validity: a survey study and an online intervention study. The lessons learned from these experiences generated three types of strategies researchers can use to reduce the likelihood of participant misrepresentation for eligibility in Web‐based research. Examples of procedural/design strategies, technical/software strategies and data analytic strategies are provided along with the methodological strengths and limitations of specific strategies. The discussion includes a series of considerations to guide researchers in the selection of strategies that may be most appropriate given the aims, resources and target population of their studies. Copyright © 2014 John Wiley & Sons, Ltd.     

Aortic function is compromised in a rat model of polycystic ovary syndrome

BACKGROUND: Arterial mechanical parameters are modified in women with polycystic ovary syndrome (PCOS), before and during pregnancy. This study tested the hypothesis that aortic mechanics and endothelial function are modified in the mifepristone-treated rat model of PCOS. METHODS: Female rats injected daily with mifepristone or vehicle for 7-9 days were assessed by ultrasound to allow estimation of aortic stiffness index and compliance. The influence of acetylcholine (ACh) and sodium nitroprusside (SNP) on dissected phenylephrine-contracted aortic rings was assessed. RESULTS: Aortic compliance was reduced by 67% in mifepristone-treated rats versus controls (P<0.05), while stiffness index was increased 2.3-fold (P<0.02). ACh-induced dilation was less in aortic rings from mifepristone-treated rats (P=0.022) and was less sensitive to the nitric oxide (NO) synthase inhibitor NG-nitro-L-arginine methyl ester (L-NAME) (P<0.001), while SNP-induced dilation was greater (P=0.001). CONCLUSIONS: Aortic mechanics in vivo and endothelial function in vitro were consistently perturbed in mifepristone-treated rats. Aortic ring behaviour suggested that NO release was depressed or degradation elevated, with a compensatory increase in NO sensitivity and/or activation of a non-NO-mediated relaxation mechanism. The mifepristone-treated rat is a valid model for investigation of the vascular deficits seen in PCOS.     

Direct isolation of Candida spp. from blood cultures on the chromogenic medium CHROMagar Candida

CHROMagar Candida is a selective and differential chromogenic medium that has been shown to be useful for identification of Candida albicans, Candida krusei, Candida tropicalis, and perhaps Candida glabrata. Colony morphology and color have been well defined when CHROMagar Candida has been used to isolate yeast directly from clinical specimens, including stool, urine, respiratory, vaginal, oropharyngeal, and esophageal sources. Direct isolation of yeast on CHROMagar Candida from blood cultures has not been evaluated. We evaluated whether the color and colony characteristics produced by Candida spp. on CHROMagar Candida were altered when yeasts were isolated directly from blood cultures. Fifty clinical isolates of Candida were inoculated into aerobic and anaerobic blood culture bottles and incubated at 35 degrees C in an automated blood culture system. When growth was detected, an aliquot was removed and plated onto CHROMagar Candida. As a control, CHROMagar Candida plates were inoculated with the same isolate of yeast grown on Sabouraud dextrose agar simultaneously. No significant difference was detected in color or colony morphology between the blood and control isolates in any of the tested organisms. All C. albicans (n = 12), C. tropicalis (n = 12), C. glabrata (n = 9), and C. krusei (n = 5) isolates exhibited the expected species-specific colony characteristics and color, whether isolated directly from blood or from control cultures. CHROMagar Candida can be reliably used for direct isolation of yeast from blood cultures. Direct isolation could allow mycology laboratories to more rapidly identify Candida spp., enable clinicians to more quickly make antifungal agent selections, and potentially decrease patient morbidity and mortality.     

Diversity and repertoire of IgW and IgM <Emphasis Type="Italic">VH</Emphasis> families in the newborn nurse shark

Background

Adult cartilaginous fish express three immunoglobulin (Ig) isotypes, IgM, IgNAR and IgW. Newborn nurse sharks, Ginglymostoma cirratum, produce 19S (multimeric) IgM and monomeric/dimeric IgM_1gj, a germline-joined, IgM-related VH, and very low amounts of 7S (monomeric) IgM and IgNAR proteins. Newborn IgNAR VH mRNAs are diverse in the complementarity-determining region 3 (CDR3) with non-templated nucleotide (N-region) addition, which suggests that, unlike in many other vertebrates, terminal deoxynucleotidyl transferase (TdT) expressed at birth is functional. IgW is present in the lungfish, a bony fish sharing a common ancestor with sharks 460 million years ago, implying that the IgW VH family is as old as the IgM VH family. This nurse shark study examined the IgM and IgW VH repertoire from birth through adult life, and analyzed the phylogenetic relationships of these gene families.

Results

IgM and IgW VH cDNA clones isolated from newborn nurse shark primary and secondary lymphoid tissues had highly diverse and unique CDR3 with N-region addition and VDJ gene rearrangement, implicating functional TdT and RAG gene activity. Despite the clear presence of N-region additions, newborn CDR3 were significantly shorter than those of adults. The IgM clones are all included in a conventional VH family that can be classified into five discrete groups, none of which is orthologous to IgM VH genes in other elasmobranchs. In addition, a novel divergent VH family was orthologous to a published monotypic VH horn shark family. IgW VH genes have diverged sufficiently to form three families. IgM and IgW VH serine codons using the potential somatic hypermutation hotspot sequence occur mainly in VH framework 1 (FR1) and CDR1. Phylogenetic analysis of cartilaginous fish and lungfish IgM and IgW demonstrated they form two major ancient gene groups; furthermore, these VH genes generally diversify (duplicate and diverge) within a species.

Conclusion

As in ratfish, sandbar and horn sharks, most nurse shark IgM VH genes are from one family with multiple, heterogeneous loci. Their IgW VH genes have diversified, forming at least three families. The neonatal shark Ig VH CDR3 repertoire, diversified via N-region addition, is shorter than the adult VDJ junction, suggesting one means of postnatal repertoire diversification is expression of longer CDR3 junctions.

     

Differential effects of arginine,glutamate and phosphoarginine on Ca<Superscript>2+</Superscript>-activation properties of muscle fibres from crayfish and rat

The effects of two amino acids, arginine which has a positively charged side-chain and glutamate which has a negatively charged side-chain on the Ca²⁺-activation properties of the contractile apparatus were examined in four structurally and functionally different types of skeletal muscle; long- and short-sarcomere fibres from the claw muscle of the yabby (a freshwater decapod crustacean), and fast- and slow-twitch fibres from limb muscles of the rat. Single skinned fibres were activated in carefully balanced solutions of different pCa (-log₁₀[Ca²⁺]) that either contained the test solute (“test”) or not (“control”). The effect of phosphoarginine, a phosphagen that bears a nett negative charge, was also compared to the effects of arginine. Results show that (i) arginine (33-36 mmol l^-1) significantly shifted the force–pCa curve by 0.08–0.13 pCa units in the direction of increased sensitivity to Ca²⁺-activated contraction in all fibre types; (ii) phosphoarginine (9–10 mmol l^-1) induced a significant shift of the force–pCa curve by 0.18–0.24 pCa units in the direction of increased sensitivity to Ca²⁺ in mammalian fast- and slow-twitch fibres, but had no significant effects on the force–pCa relation in either long- or short-sarcomere crustacean fibres; (iii) glutamate (36–40 mmol l^-1), like arginine affected the force–pCa relation of all fibre types investigated, but in the opposite direction, causing a significant decrease in the sensitivity to Ca²⁺-activated contraction by 0.08–0.19 pCa units; (iv) arginine, phosphoarginine and glutamate had little or no effect on the maximum Ca²⁺-activated force of crustacean and mammalian fibres. The results suggest that the opposing effects of glutamate and arginine are not related to simply their charge structure, but must involve complex interactions between these molecules, Ca²⁺ and the regulatory and other myofibrillar proteins.     

Lack of horizontal gene transfer of methicillin-resistance genetic determinants from PBP2a-positive, coagulase-negative staphylococci to methicillin-sensitive Staphylococcus aureus using transcutaneous electrical nerve stimulation (TENS)

Previous research shows that approximately half of the coagulase-negative staphylococci (CNS) isolated from patients in the intensive care unit (ICU) at Belfast City Hospital were resistant to methicillin. The presence of this relatively high proportion of methicillin-resistance genetic material gives rise to speculation that these organisms may act as potential reservoirs of methicillin-resistance genetic material to methicillin-sensitive Staphylococcus aureus (MSSA). Mechanisms of horizontal gene transfer from PBP2a-positive CNS to MSSA, potentially transforming MSSA to MRSA, aided by electroporation-type activities such as transcutaneous electrical nerve stimulation (TENS), should be considered. Methicillin-resistant CNS (MR-CNS) isolates are collected over a two-month period from a variety of clinical specimen types, particularly wound swabs. The species of all isolates are confirmed, as well as their resistance to oxacillin by standard disc diffusion assays. In addition, MSSA isolates are collected over the same period and confirmed as PBP2a-negative. Electroporation experiments are designed to mimic the time/voltage combinations used commonly in the clinical application of TENS. No transformed MRSA were isolated and all viable S. aureus cells remained susceptible to oxacillin and PBP2a-negative. Experiments using MSSA pre-exposed to sublethal concentrations of oxacillin (0.25 microg/mL) showed no evidence of methicillin gene transfer and the generation of an MRSA. The study showed no evidence of horizontal transfer of methicillin resistance genetic material from MR-CNS to MSSA. These data support the belief that TENS and the associated time/voltage combinations used do not increase conjugational transposons or facilitate horizontal gene transfer from MR-CNS to MSSA.     

Profiles of Irish survivors of institutional abuse with different adult attachment styles

Two hundred and forty seven survivors of institutional abuse in Ireland were classified with the Experiences in Close Relationships Inventory as having fearful (44%), preoccupied (13%), dismissive (27%), or secure (17%) adult attachment styles. The group with the secure adult attachment style had the most positive profile, while the most negative profile occurred for the fearful group in terms of DSM IV diagnoses and scores on the Trauma Symptom Inventory, the Global Assessment of Functioning Scale, the World Health Organization Quality of Life 100 scale, and the Kansas Marital Satisfaction Scale. The profile of the preoccupied group was more similar to that of the fearful group. The profile of the dismissive group was more similar to that of the secure group.     

Group interventions and the limits of behavioral medicine

A wide range of interventions has been devised to address health hazards in the social and physical environment. The authors propose a 2-dimensional matrix to organize these interventions. The timing of interventions is divided into 4 stages: preventing exposure to hazard (proactive primary prevention), preventing symptoms from appearing (reactive primary prevention), preventing early symptoms from becoming chronic or leading to disease (secondary prevention), and managing the disease (tertiary prevention). The level at which the intervention is targeted is divided into 2 categories: micro (individual or family) and macro (more aggregate social level). Large-scale interventions such as media campaigns can target either individual health behaviors (microlevel) or the environment (macrolevel). This typology is illustrated with interventions designed to prevent or ameliorate the health consequences of adverse employment changes such as job loss. The analysis concludes that behavioral medicine and public health approaches are differentially suited to different intervention types.