641 research outputs found
Association between bacterial vaginosis and cervical intraepithelial neoplasia: systematic review and meta-analysis
Objective: Bacterial vaginosis (BV), the most common vaginal disorder among women of reproductive age, has been suggested as co-factor in the development of cervical cancer. Previous studies examining the relationship between BV and cervical intra-epithelial neoplasia (CIN) provided inconsistent and conflicting results. The aim of this study is to clarify the association between these two conditions.
Methods: A systematic review and meta-analysis were conducted to summarize published literature on the association between BV and cervical pre-cancerous lesions. An extensive search of electronic databases Medline (Pubmed) and Web of Science was performed. The key words 'bacterial vaginosis' and 'bacterial infections and vaginitis' were used in combination with 'cervical intraepithelial neoplasia', 'squamous intraepithelial lesions', 'cervical lesions', 'cervical dysplasia', and 'cervical screening'. Eligible studies required a clear description of diagnostic methods used for detecting both BV and cervical precancerous lesions. Publications were included if they either reported odds ratios (OR) and corresponding 95% confidence intervals (CI) representing the magnitude of association between these two conditions, or presented data that allowed calculation of the OR.
Results: Out of 329 articles, 17 cross-sectional and 2 incidence studies were selected. In addition, two studies conducted in The Netherlands, using the national KOPAC system, were retained. After testing for heterogeneity and publication bias, meta-analysis and meta-regression were performed, using a random effects model. Although heterogeneity among studies was high (chi(2) = 164.7, p < 0.01, I-2 = 88.5), a positive association between BV and cervical pre-cancerous lesions was found, with an overall estimated odds ratio of 1.51 (95% CI, 1.24-1.83). Meta-regression analysis could not detect a significant difference between studies based on BV diagnosis, CIN diagnosis or study population.
Conclusions: Although most studies were cross-sectional and heterogeneity was high, this meta-analysis confirms a connection between BV and CIN
Acquired epidermodysplasia verruciformis due to multiple and unusual HPV infection among vertically-infected, HIV-positive adolescents in Zimbabwe.
BACKGROUND: We have previously described the presentation of epidermodysplasia verruciformis (EV)-like eruptions in almost a quarter of hospitalized adolescents with vertically-acquired human immunodeficiency virus (HIV) infection in Harare, Zimbabwe, a region with a high prevalence of HIV infection. METHODS: We performed a clinical case note review and skin biopsy from affected sites in 4 HIV-infected adolescents with EV-like lesions in Harare. Biopsies were processed for histology and for human papillomavirus (HPV) typing. RESULTS: All patients had long-standing skin lesions that pre-dated the diagnosis of HIV by several years. The histology of skin biopsies from all patients was consistent with EV. In each biopsy, EV-associated β-HPV type 5 was identified (additionally, type 19 was found in 1 biopsy). Cutaneous wart-associated HPV types 1 and 2 were detected in all biopsies, together with genital lesion-associated HPV types 6, 16, and 52, (as well as ≥3 other genital lesion-associated HPV types). Despite immune reconstitution with combination antiretroviral therapy (cART), there was no improvement in EV-like lesions in any patient. CONCLUSIONS: EV is a disfiguring and potentially stigmatizing condition among this patient group and is difficult to treat; cART appears to have no impact on the progression of skin disease. Among adolescents with longstanding HIV-induced immunosuppression and with high levels of sun exposure, close dermatological surveillance for potential skin malignancy is required
Bacterial vaginosis is associated with uterine cervical human papillomavirus infection: a meta-analysis
Background: Bacterial vaginosis (BV), an alteration of vaginal flora involving a decrease in Lactobacilli and predominance of anaerobic bacteria, is among the most common cause of vaginal complaints for women of childbearing age. It is well known that BV has an influence in acquisition of certain genital infections. However, association between BV and cervical human papillomavirus (HPV) infection has been inconsistent among studies. The objective of this meta-analysis of published studies is to clarify and summarize published literature on the extent to which BV is associated with cervical HPV infection.
Methods: Medline and Web of Science were systematically searched for eligible publications until December 2009. Articles were selected based on inclusion and exclusion criteria. After testing heterogeneity of studies, metaanalysis was performed using random effect model.
Results: Twelve eligible studies were selected to review the association between BV and HPV, including a total of 6,372 women. The pooled prevalence of BV was 32%. The overall estimated odds ratio (OR) showed a positive association between BV and cervical HPV infection (OR, 1.43; 95% confidence interval, 1.11-1.84).
Conclusion: This meta-analysis of available literature resulted in a positive association between BV and uterine cervical HPV infection
Online Talent Platforms, Labour Market Intermediaries and the Changing World of Work. Independent study prepared by CEPS and IZA for the World Employment Confederation-Europe and UNI Europa May 2018
By comparing the online talent platform economy and the temporary agency work sector, this study aims to contribute to a rapidly growing literature on new forms of work and their impact on the labour market. It shows that online talent platforms and temporary work agencies do have features in common, but there are also significant differences between the two, which make it difficult to use temporary agency work as a model for the online talent platform economy; in many cases, it would not be a good fit. That being said, the call by policy-makers, social partners and other stakeholders for a level playing field should not be overlooked. Furthermore, the study also confirms that any comparison of the online talent platform economy and the temporary agency work sector is hampered by a lack of data. In order to address this issue, continued monitoring and much more transparency of online talent platforms will be needed, as well as further data collection and analysis of both the online talent platforms and the temporary work agencies. These efforts are important because more flexible forms of work are likely to become increasingly prevalent in the future
ViVaMBC: estimating viral sequence variation in complex populations from illumina deep-sequencing data using model-based clustering
Background: Deep-sequencing allows for an in-depth characterization of sequence variation in complex populations. However, technology associated errors may impede a powerful assessment of low-frequency mutations. Fortunately, base calls are complemented with quality scores which are derived from a quadruplet of intensities, one channel for each nucleotide type for Illumina sequencing. The highest intensity of the four channels determines the base that is called. Mismatch bases can often be corrected by the second best base, i.e. the base with the second highest intensity in the quadruplet. A virus variant model-based clustering method, ViVaMBC, is presented that explores quality scores and second best base calls for identifying and quantifying viral variants. ViVaMBC is optimized to call variants at the codon level (nucleotide triplets) which enables immediate biological interpretation of the variants with respect to their antiviral drug responses.
Results: Using mixtures of HCV plasmids we show that our method accurately estimates frequencies down to 0.5%. The estimates are unbiased when average coverages of 25,000 are reached. A comparison with the SNP-callers V-Phaser2, ShoRAH, and LoFreq shows that ViVaMBC has a superb sensitivity and specificity for variants with frequencies above 0.4%. Unlike the competitors, ViVaMBC reports a higher number of false-positive findings with frequencies below 0.4% which might partially originate from picking up artificial variants introduced by errors in the sample and library preparation step.
Conclusions: ViVaMBC is the first method to call viral variants directly at the codon level. The strength of the approach lies in modeling the error probabilities based on the quality scores. Although the use of second best base calls appeared very promising in our data exploration phase, their utility was limited. They provided a slight increase in sensitivity, which however does not warrant the additional computational cost of running the offline base caller. Apparently a lot of information is already contained in the quality scores enabling the model based clustering procedure to adjust the majority of the sequencing errors. Overall the sensitivity of ViVaMBC is such that technical constraints like PCR errors start to form the bottleneck for low frequency variant detection
HLA Immunogenotype Determines Persistent Human Papillomavirus Virus Infection in HIV-Infected Patients Receiving Antiretroviral Treatment
A proportion of human immunodeficiency virus (HIV)–infected patients develop persistent, stigmatizing human papillomavirus (HPV)–related cutaneous and genital warts and anogenital (pre)cancer. This is the first study to investigate immunogenetic variations that might account for HPV susceptibility and the largest to date to categorize the HPV types associated with cutaneous warts in HIV-positive patients. The HLA class I and II allele distribution was analyzed in 49 antiretroviral (ART)–treated HIV-positive patients with persistent warts, 42 noninfected controls, and 46 HIV-positive controls. The allele HLA-B*44 was more frequently identified in HIV-positive patients with warts (P = .004); a susceptible haplotype (HLA-B*44, HLA-C*05; P = .001) and protective genes (HLA-DQB1*06; P = .03) may also contribute. Cutaneous wart biopsy specimens from HIV-positive patients harbored common wart types HPV27/57, the unusual wart type HPV7, and an excess of Betapapillomavirus types (P = .002), compared with wart specimens from noninfected controls. These findings suggest that HLA testing might assist in stratifying those patients in whom vaccination should be recommended
How Good a Clock is Rotation? The Stellar Rotation-Mass-Age Relationship for Old Field Stars
The rotation-mass-age relationship offers a promising avenue for measuring
the ages of field stars, assuming the attendant uncertainties to this technique
can be well characterized. We model stellar angular momentum evolution starting
with a rotation distribution from open cluster M37. Our predicted
rotation-mass-age relationship shows significant zero-point offsets compared to
an alternative angular momentum loss law and published gyrochronology
relations. Systematic errors at the 30 percent level are permitted by current
data, highlighting the need for empirical guidance. We identify two fundamental
sources of uncertainty that limit the precision of rotation-based ages and
quantify their impact. Stars are born with a range of rotation rates, which
leads to an age range at fixed rotation period. We find that the inherent
ambiguity from the initial conditions is important for all young stars, and
remains large for old stars below 0.6 solar masses. Latitudinal surface
differential rotation also introduces a minimum uncertainty into rotation
period measurements and, by extension, rotation-based ages. Both models and the
data from binary star systems 61 Cyg and alpha Cen demonstrate that latitudinal
differential rotation is the limiting factor for rotation-based age precision
among old field stars, inducing uncertainties at the ~2 Gyr level. We also
examine the relationship between variability amplitude, rotation period, and
age. Existing ground-based surveys can detect field populations with ages as
old as 1-2 Gyr, while space missions can detect stars as old as the Galactic
disk. In comparison with other techniques for measuring the ages of lower main
sequence stars, including geometric parallax and asteroseismology,
rotation-based ages have the potential to be the most precise chronometer for
0.6-1.0 solar mass stars.Comment: For a brief video explaining the key results of this paper, see
http://www.youtube.com/user/OSUAstronom
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