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.     

Clinical and Epidemiological Relevance of Quantitating Hepatitis E Virus-Specific Immunoglobulin M

Diagnosis of acute hepatitis E by detection of hepatitis E virus (HEV)-specific immunoglobulin M (IgM) is an established procedure. We investigated whether quantitation of HEV IgM and its ratio to HEV total Ig furnished more information than conventional IgM tests that are interpreted as positive or negative. A previously described indirect immunoassay for total Ig against a baculovirus-expressed HEV capsid protein was modified to quantitate HEV-specific IgM in Walter Reed (WR) antibody units by using a reference antiserum and the four-parameter logistic model. A receiver-operating characteristics curve derived from 197 true-positive specimens and 449 true-negative specimens identified 30 WR units/ml as an optimum cut point. The median HEV IgM level in 36 patients with acute hepatitis E fell from 3,000 to 100 WR units/ml over 6 months, suggesting that 100 WR units/ml would be a more appropriate cut point for distinguishing recent from remote IgM responses. Among three hepatitis E case series, determination of the HEV IgM-to-total-Ig ratio in acute-phase serum revealed that most patients had high ratios consistent with primary infections whereas a few had low ratios, suggesting that they had sustained reinfections that elicited anamnestic antibody responses. The diagnostic utility of the new IgM test was similar to that of a commercially available test that uses different HEV antigens. In conclusion, we found that HEV IgM can be detected specifically in >95% of acute hepatitis E cases defined by detection of the virus genome in serum and that quantitation of HEV IgM and its ratio to total Ig provides insight into infection timing and prior immunity.     

Dissemination of extended-spectrum beta-lactamase-producing Enterobacteriaceae in pediatric intensive care units

To study the growing trend of extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae in pediatric intensive care units (PICUs), 88 nonrepetitive ESBL-producing isolates were prospectively collected and analyzed by molecular methods during a 16-month period. The emergence and dissemination of ESBL-producing Enterobacteriaceae in PICUs are the consequence of the clonal dissemination of a few epidemic strains along with the horizontal transmission of resistance gene-carrying plasmids among bacterial organisms.     

ORIGINAL ARTICLE: Maternal Plasma Concentration of the Pro‐Inflammatory Adipokine Pre‐B‐Cell‐Enhancing Factor (PBEF)/Visfatin Is Elevated In Pregnant Patients with Acute Pyelonephritis

Citation Mazaki‐Tovi S, Vaisbuch E, Romero R, Kusanovic JP, Chaiworapongsa T, Kim SK, Nhan‐Chang C‐L, Gomez R, Yoon BH, Yeo L, Mittal P, Ogge G, Gonzalez JM, Hassan SS. Maternal plasma concentration of the pro‐inflammatory adipokine pre‐B‐cell‐enhancing factor (PBEF)/visfatin is elevated in pregnant patients with acute pyelonephritis. Am J Reprod Immunol 2010; 63: 252–262 Problem Visfatin/pre‐B‐cell‐enhancing factor (PBEF) has been implicated in the regulation of the innate immune system, as well as in glucose metabolism. Specifically, visfatin plays a requisite role in delayed neutrophil apoptosis in patients with sepsis. The aim of this study was to determine whether pyelonephritis during pregnancy is associated with changes in maternal plasma visfatin concentration in normal weight and overweight/obese patients. Method of study This cross‐sectional study included the following groups: (1) normal pregnant women (n = 200) and (2) pregnant women with pyelonephritis (n = 40). Maternal plasma visfatin concentrations were determined by ELISA. Non‐parametric statistics was used for analyses. Results (1) The median maternal plasma visfatin concentration was significantly higher in patients with pyelonephritis than in those with a normal pregnancy; (2) among overweight/obese pregnant women, those with pyelonephritis had a significantly higher median plasma visfatin concentration than women with a normal pregnancy; and (3) pyelonephritis was independently associated with higher maternal plasma visfatin concentrations after adjustment for maternal age, pre‐gestational body mass index, smoking status, gestational age at sampling, and birthweight. Conclusion Acute pyelonephritis during pregnancy is associated with a high circulating maternal visfatin concentration. These findings suggest that visfatin/PBEF may play a role in the regulation of the complex and dynamic crosstalk between inflammation and metabolism during pregnancy.     

Heteroarm Star Polystyrene‐block‐Poly(4‐vinylpyridine): Multiple Morphologies in Dilute Solutions

Synthesis and solution morphologies of four new heteroarm star polystyrene‐block‐poly(4‐vinylpyridine) were studied. As the water content increased, a morphological transformation of heteroarm PS₄‐P4VP₄ from spheres to cylinders, vesicles, and large compound vesicles was observed. The morphology of PS₄‐P4VP₄ in the solvent mixture of DMF/water or 1,4‐dioxane/water was spherical, but changed to large compound micelles in THF/water. As the P4VP molar ratio decreased, the morphology changed from spherical mixed with cylindrical to vesicles, giant vesicles, and then to LCMs. The present study demonstrated the formation of multiple morphologies through manipulating solvent polarity and block ratio in dilute solution.

     

Extended epidemic of nosocomial urinary tract infections caused by Serratia marcescens

In recent years a significant increase in the incidence of Serratia marcescens infections was noted at the Chang Gung Memorial Hospital, Taoyuan, Taiwan. A review of laboratory (1991 to 2002) and infection control (1995 to 2002) records showed the possibility of an extended epidemic of nosocomial urinary tract infections (UTIs) caused by S. marcescens. Therefore, in 1998 and 1999, 87 isolates were collected from patients with such infections and examined and another 51 isolates were collected in 2001 and 2002. The patients were mostly elderly or the infections were associated with the use of several invasive devices. S. marcescens was usually the only pathogen found in urine cultures in our study. Neither prior infections nor disseminated infections with the organism were observed in these patients. Resistance to most antibiotics except imipenem was noted. Two genotyping methods, pulsed-field gel electrophoresis and infrequent-restriction-site PCR, were used to examine the isolates. A total of 12 genotypes were identified, and 2 predominant genotypes were found in 72 (82.8%) of the 87 isolates derived from all over the hospital. However, 63.9% of the isolates of the two genotypes were from neurology wards. A subsequent intervention by infection control personnel reduced the infection rate greatly. The number and proportion of the two predominant genotypes were significantly reduced among the 51 isolates collected in 2001 and 2002. Thus, a chronic and long-lasting epidemic of nosocomial UTIs caused by S. marcescens was identified and a successful intervention was carried out. Both a cautious review of laboratory and infection control data and an efficient genotyping system are necessary to identify such a cryptic epidemic and further contribute to the quality of patient care.     

Waterborne Polyurethane Colloids with Sensitive CO2‐Switchable Hydrophilic/Hydrophobic Properties

A novel conceptual approach to gas‐responsive functionality, with the capability to tune the amphiphilic characteristics of existing waterborne polyurethanes (WPUs), via CO₂/N₂ bubbling in aqueous solution, is exploited. In this study, a series of functional WPUs are successfully prepared. These colloids exhibit high aqueous stability, excellent capability for emulsification/demulsification as a surfactant, and reversible hydrophilic/hydrophobic phase transition owing to reversible formation of carboxylic acid moieties induced by bubbling CO₂ gas. More interestingly, when carboxylated multiwalled carbon nanotubes (CNTs) are covalently incorporated into these WPUs, the CNT exhibits CO₂‐switchable amphiphilic behavior in a two‐phase mixture of n‐butanol (BuOH)/deionized water, forming a stable hydrophobic CNT dispersion in BuOH upon CO₂ bubbling, and reversibly reverting to the previous hydrophilic CNT dispersion in water upon N₂ bubbling. With simple preparation and switchable amphiphilic properties, these CO₂‐responsive WPUs offer a paradigm for the development of multifunctional gas‐responsive polymers.     

Dendritic fibromyxolipoma: A variant of spindle cell lipoma with extensive myxoid change,with cytogenetic evidence

Dendritic fibromyxolipoma (DFML), a rare, recently described distinct benign soft tissue tumor, has many clinicopathological features reminiscent of spindle cell lipoma and solitary fibrous tumor with myxoid change. It is distinguished histologically from both entities by the presence of spindle and stellate cells with dendritic cytoplasmic prolongations, prominent myxoid stroma with abundant keloidal collagen and occasional small plexiform vascular proliferation. We describe a case of histologically confirmed DFML of the left shoulder in a 67‐year‐old male, in which subsequent cytogenetic analysis revealed deletion involving 13q14.3 region in all the tumor cells, typically detected in spindle cell lipoma. In the presence of many clinicopathological similarities between DFML and spindle cell lipoma including chromosomal abnormalities, we postulate that DFML is merely a rare variant of spindle cell lipoma with extensive myxoid degeneration, and may not be considered as a separate entity. The possible differential diagnosis and their distinguishing features are briefly discussed.