We examined the community ecology of vaginal microbial samples taken from pregnant women with previous preterm birth experience to investigate whether targeted pathogenic and commensal bacteria are related to risk of preterm birth in the current pregnancy. We found a significant correlation between the community structure of selected bacteria and birth outcome, but the correlation differed among self-reported racial/ethnic groups. Using a community ordination analysis, we observed infrequent co-occurrence of Mycoplasma and bacteria vaginosis associated bacteria 3 (BVAB3) among black and Hispanic participants. In addition, we found that the vaginal bacteria responded differently in different racial/ethnic groups to modifications of maternal behavioral (ie, douching and smoking) and biological traits (ie, body mass index [BMI]). Even after accounting for these maternal behaviors and traits, the selected vaginal bacteria was significantly associated with preterm birth among black and Hispanic participants. By contrast, white participants did not exhibit significant correlation between microbial community and birth outcome. Findings from this study affirm the necessity of considering women’s race/ethnicity when evaluating the correlation between vaginal bacteria and preterm birth. The study also illustrates the importance of studying the vaginal microbiota from an ecological perspective, and demonstrates the power of ecological community analysis to improve understanding of infectious disease.
This is the post-randomization shortest cerclage measurement of each participant who entered the randomization (which means their cerclage measurement was less than 25mm at one of the visits). The data were provided by John Owens from U Alabama. No codebook was associated with it.
This is the clinical data and vaginal measurement data U of Alabama provided. The column names are fairly self-explanatory. There was not an original data codebook associated with it. There has been some email exchanges to clarify several variables, which is recorded in the Word file "cerclage_owenscodebook.doc".
This is the bacterial DNA data extracted from the gram stain slides. The targeted bacteria genera and species include: Atopobium spp., bacterial vaginosis-associated bacterium (BVAB) types 1, 2 and 3 in the order Clostridiales, Escherichia coli, Gardnerella vaginalis, Group B Streptococcus, Lactobacillus spp., Mobiluncus spp., Mycoplasma spp., and Ureaplasma spp. We also used a primer set for Lactic Acid Bacteria (LAB) that includes lactic acid producing bacteria of the genera Lactobacillus, Pediococcus, Leuconostoc, and Weissella. We calculated the relative proportion of each bacterial taxon using the bacterial copies measured by each specific bacteria primer divided by the total bacterial copies. The limit of detection was 100 copies and readings lower than the limit were considered negative
This random sample of OA articles comes from Deep Blue <deepblue.lib.umich.edu/documents>, the University of Michigan’s institutional repository service. Each OA article has the following characteristics: Prior to a known date (ranging from 2006 to the 2013) these articles—the final published version—were only available by subscription. After that date, they became freely available via Deep Blue. Meanwhile, other articles from the same journal issue as the now-OA article continued to only be available to subscribers. None of the OA articles were self-selected; authors did not choose to deposit the articles in question in Deep Blue, since we made them open via blanket licensing agreements between the publishers and the library.
In a sensitive cochlea, the basilar membrane response to transient excitation of any kind--normal acoustic or artificial intracochlear excitation--consists of not only a primary impulse but also a coda of delayed secondary responses with varying amplitudes but similar spectral content around the characteristic frequency of the measurement location. The coda, sometimes referred to as echoes or ringing, has been described as a form of local, short term memory which may influence the ability of the auditory system to detect gaps in an acoustic stimulus such as speech. Depending on the individual cochlea, the temporal gap between the primary impulse and the following coda ranges from once to thrice the group delay of the primary impulse (the group delay of the primary impulse is on the order of a few hundred microseconds). The coda is physiologically vulnerable, disappearing when the cochlea is compromised even slightly. The multicomponent sensitive response is not yet completely understood. We use a physiologically-based, mathematical model to investigate (i) the generation of the primary impulse response and the dependence of the group delay on the various stimulation methods, (ii) the effect of spatial perturbations in the properties of mechanically sensitive ion channels on the generation and separation of delayed secondary responses. The model suggests that the presence of the secondary responses depends on the wavenumber content of a perturbation and the activity level of the cochlea. In addition, the model shows that the varying temporal gaps between adjacent coda seen in experiments depend on the individual profiles of perturbations. Implications for non-invasive cochlear diagnosis are also discussed.