Analysis of RNA-protein interactions by flow cytometry

Flow cytometry, in combination with advances in bead coding technologies, is maturing as a powerful high-throughput approach for analyzing molecular interactions. Applications of this technology include antibody assays and single nucleotide polymorphism mapping. This review describes the recent development of a microbead flow cytometric approach to analyze RNA-protein interactions and discusses emerging bead coding strategies that together will allow genome-wide identification of RNA-protein complexes. The microbead flow cytometric approach is flexible and provides new opportunities for functional genomic studies and small-molecule screening.     

Epidemiologic assessment of mortality, building collapse pattern, and medical response after the 1992 earthquake in Turkey. Disaster Reanimatology Study Group (DRSG)

BACKGROUND: Post-earthquake engineering and epidemiologic assessments are important for the development of injury prevention strategies. This paper describes mortality and its relationship to building collapse patterns and initial medical responses following the 1992 earthquake in Erzincan, Turkey. METHODS: The study consisted of: 1) background data collection and review; 2) design and implementation of a field survey; and 3) site inspection of building collapse patterns. The survey included: 1) national (n = 11) and local (n = 17) officials; 2) medical and search and rescue (SAR) workers (n = 38); and 3) a geographically stratified random sample of lay survivors (n = 105). The survey instruments were designed to gather information regarding location, injuries, initial actions and prior training of survivors and responders, and the location, injuries, and management of dead and dying victims. A case-control design was constructed to assess the relationship between mortality, location, and building collapse pattern. RESULTS: There was extensive structural damage throughout the region, especially in the city where mid-rise, unreinforced masonry buildings (MUMBs) incorporating a "soft" first floor design (large store windows for commercial use) and one story adobe structures were most vulnerable to collapse. Of 526 people who died in the city, 87% (n = 456) were indoors at the time of the earthquake. Of these, 92% (n = 418) died in MUMBs. Of 54 witnessed deaths, 55% (n = 28) of victims died slowly, the majority of whom (n = 26) were pinned or trapped (p < 0.05). Of 42 MUMB occupants identified through the survey, those who died (n = 25) were more likely to have been occupying the ground floor when compared with survivors (n = 28) (p < 0.01). Official medical and search and rescue responders arrived after most deaths had occurred. Prior first-aid or rescue training of lay, uninjured survivors was associated with a higher likelihood of rescuing and resuscitating others (p < 0.001). CONCLUSIONS: During an earthquake, MUMBs with soft ground floor construction are highly lethal, especially for occupants on the the ground floor, suggesting that this building type is inappropriate for areas of seismic risk. The vulnerability of MUMBs appears due to a lack of lateral force resistance as a result of the use of glass store front windows and the absence of shear walls. The prevalence of this building type in earthquake-prone regions needs to be investigated further. A large portion of victims dying in an earthquake die slowly at the scene of injury. Prior public first-aid and rescue training programs increase participation in rescue efforts in major earthquakes and may improve survival.     

Fashioning regulatory dendritic cells: what is currently in vogue?

Dendritic cells (DCs) are uniquely well-equipped antigen-presenting cells with remarkable plasticity, whose differentiation and function can be manipulated in vitro and in vivo. With increased understanding of their immunoregulatory properties, strategies to enhance DC tolerogenicity have emerged. Carefully fashioned DCs, the result of biological, pharmacological or genetic modification, hold promise as new cell-based therapies of organ allograft rejection and autoimmune diseases.     

Comparison of Cox and Gray's survival models in severe sepsis

BACKGROUND: Although survival is traditionally modeled using Cox proportional hazards modeling, this approach may be inappropriate in sepsis, in which the proportional hazards assumption does not hold. Newer, more flexible models, such as Gray's model, may be more appropriate. OBJECTIVES: To construct and compare Gray's model and two different Cox models in a large sepsis cohort. To determine whether hazards for death after sepsis were nonproportional. To explore how well the different survival modeling approaches describe these data. DESIGN: Analysis of combined data from the treatment and placebo arms of a large, negative, sepsis trial. SETTING: Intensive care units at 136 U.S. medical centers. SUBJECTS: A total of 1090 adults aged 18 yrs or older with signs and symptoms of severe sepsis and documented or probable Gram-negative infection. MEASUREMENTS: We considered 27 potential baseline risk factors and modeled survival over the 28 days after the onset of sepsis. We tested proportionality in single-variable Cox analysis using Schoenfeld residuals and log-log plots. We constructed a traditional multivariable Cox model, a multivariable Cox model with time-varying covariates, and a multivariable Gray's model. RESULTS: In single-variable analyses, 20 of the 27 potential factors were significantly associated with mortality, and 10 of 20 had nonproportional hazards. In multivariate analysis, all three models retained a very similar set of significant covariates (two models retained the identical set of nine variables, and the third differed only in that it retained the same nine plus a tenth variable). Four of the nine common covariates had nonproportional hazards. Of the three models, Gray's model best captured these changing hazard ratios over time. CONCLUSION: We confirm that many of the important predictors of mortality in severe sepsis are nonproportional and find that Gray's model seems best suited for modeling survival in this condition.     

Circulating serum xenoestrogens and mammographic breast density

Introduction

Humans are widely exposed to estrogenically active phthalates, parabens, and phenols, raising concerns about potential effects on breast tissue and breast cancer risk. We sought to determine the association of circulating serum levels of these chemicals (reflecting recent exposure) with mammographic breast density (a marker of breast cancer risk).

Methods

We recruited postmenopausal women aged 55 to 70 years from mammography clinics in Madison, Wisconsin (N = 264). Subjects completed a questionnaire and provided a blood sample that was analyzed for mono-ethyl phthalate, mono-butyl phthalate, mono-benzyl phthalate, butyl paraben, propyl paraben, octylphenol, nonylphenol, and bisphenol A (BPA). Percentage breast density was measured from mammograms by using a computer-assisted thresholding method.

Results

Serum BPA was positively associated with mammographic breast density after adjusting for age, body mass index, and other potentially confounding factors. Mean percentage density was 12.6% (95% confidence interval (CI), 11.4 to 14.0) among the 193 women with nondetectable BPA levels, 13.7% (95% CI, 10.7 to 17.1) among the 35 women with detectable levels below the median (<0.55 ng/ml), and 17.6% (95% CI, 14.1 to 21.5) among the 34 women with detectable levels above the median (>0.55 ng/ml; P_trend = 0.01). Percentage breast density was also elevated (18.2%; 95% CI, 13.4 to 23.7) among the 18 women with serum mono-ethyl phthalate above the median detected level (>3.77 ng/ml) compared with women with nondetectable BPA levels (13.1%; 95% CI, 11.9 to 14.3; P_trend = 0.07). No other chemicals demonstrated associations with percentage breast density.

Conclusions

Postmenopausal women with high serum levels of BPA and mono-ethyl phthalate had elevated breast density. Further investigation of the impact of BPA and mono-ethyl phthalate on breast cancer risk by using repeated serum measurements or other markers of xenoestrogen exposure are needed.