A 3D-printed flow-cell for on-grid purification of electron microscopy samples directly from lysate.

While recent advances in cryo-EM, coupled with single particle analysis, have the potential to allow structure determination in a near-native state from vanishingly few individual particles, this vision has yet to be realised in practise. Requirements for particle numbers that currently far exceed the theoretical lower limits, challenges with the practicalities of achieving high concentrations for difficult-to-produce samples, and inadequate sample-dependent imaging conditions, all result in significant bottlenecks preventing routine structure determination using cryo-EM. Therefore, considerable efforts are being made to circumvent these bottlenecks by developing affinity purification of samples on-grid; at once obviating the need to produce large amounts of protein, as well as more directly controlling the variable, and sample-dependent, process of grid preparation. In this proof-of-concept study, we demonstrate a further practical step towards this paradigm, developing a 3D-printable flow-cell device to allow on-grid affinity purification from raw inputs such as whole cell lysates, using graphene oxide-based affinity grids. Our flow-cell device can be interfaced directly with routinely-used laboratory equipment such as liquid chromatographs, or peristaltic pumps, fitted with standard chromatographic (1/16") connectors, and can be used to allow binding of samples to affinity grids in a controlled environment prior to the extensive washing required to remove impurities. Furthermore, by designing a device which can be 3D printed and coupled to routinely used laboratory equipment, we hope to increase the accessibility of the techniques presented herein to researchers working towards single-particle macromolecular structures.

Chlamydia trachomatis and risk of cervical intraepithelial neoplasia grade 3 or worse in women with persistent human papillomavirus infection: a cohort study.

OBJECTIVES: Some studies suggest that Chlamydia trachomatis (CT) enhances cervical carcinogenesis; however, a possible confounding effect of persistent human papillomavirus (HPV) infection was not addressed. We examined the potential role of CT infection in the development of subsequent cervical intraepithelial neoplasia grade 3 or worse (CIN3+) in women with prevalent HPV infection and in a subgroup of women with persistent HPV infection. METHODS: Participants in this population-based cohort study underwent a structured interview, including history of CT infection, and subsequently cervical exfoliated cells were obtained for HPV DNA and CT DNA testing. Women with high-risk HPV DNA infection and no prevalent cervical disease constituted the overall study population (n=1390). A subgroup of women with persistent HPV infection (n=320) was also identified. All women were passively followed for development of cervical lesions in the national Pathology Data Bank. HRs and 95% CIs for CIN3+ during follow-up (up to 19 years) were estimated in an accelerated failure time model. RESULTS: Women who reported more than one CT infection had a statistically significantly increased risk of CIN3+ (high-risk HPV-positive, HR=2.51, 95% CI 1.44 to 4.37) (persistent HPV infection, HR=3.65, 95% CI 1.53 to 8.70). We found no association between CT DNA and subsequent risk of CIN3+ among women who were HPV-positive or had a persistent HPV infection at baseline. CONCLUSIONS: Repeated CT infections increased the risk of CIN3+ among women with prevalent as well as persistent high-risk HPV infection.

Sociodemographic factors and risk-taking behaviour during adolescence and obesity among more than 40 000 Danes.

OBJECTIVE: The prevalence of obesity has increased in the last decades in the Western world. The aim of the present study was to examine the association between risk-taking behaviour in adolescence and adult obesity in men and women. Furthermore, we wished to describe social differences in obesity in Denmark. DESIGN: Two population-based questionnaire studies (2004-2005 and 2006-2007) were used to collect information on weight and height, sociodemographic factors and factors regarding risk-taking behaviour during adolescence. Data were analysed using multivariate logistic regression. SETTING: Denmark. SUBJECTS: Individuals aged 18-45 years (men: n 22 827, participation rate 71·0%; women: n 20 870, participation rate 81·4%). RESULTS: The prevalence of overweight and obesity was respectively 37·8% and 10·6% in men and 20·1% and 9·7% in women. In both sexes, obesity was found to be associated with older age, low level of schooling and living outside the capital centre. In relation to risk-taking behaviour, young age (≤13 years) at first intercourse significantly increased the odds of being obese in adulthood (men: OR = 1·34, 95% CI 1·04, 1·71; women: OR = 1·66, 95% CI 1·27, 1·99). In women specifically, young age at start drinking alcohol (≤12 years) was associated with obesity. CONCLUSIONS: Sociodemographic factors, in particular age, level of schooling and area of residence, are associated with obesity in both men and women. Risk-taking behaviour during adolescence seems to cluster in both obese men and obese women, however most convincingly in women.

Human papillomavirus (HPV) vaccination and subsequent sexual behaviour: evidence from a large survey of Nordic women.

OBJECTIVE: To assess whether recipients and non-recipients of the human papillomavirus (HPV) vaccine subsequently differ in terms of sexual risk taking behaviour. DESIGN: Cross-sectional survey. Sequential analyses constructed from self-reported age at vaccination, age at first intercourse and age at response. SETTING: A random selection of women aged 18-46 years living in Denmark, Norway and Sweden in 2011-2012, eligible for opportunistic or organized catch-up HPV vaccination. PARTICIPANTS: A total of 3805 women reported to have received the HPV vaccine and 40,247 reported not to have received it. Among vaccinees, 1539 received the HPV vaccine before or at the same age as sexual debut, of which 476 and 1063 were eligible for organized catch-up and opportunistic vaccination, respectively. MAIN OUTCOME MEASURES: Self-reported sexual behaviour, compared by hazard ratios and odds ratios for women who received the HPV vaccine before or at the same age as sexual debut versus women who did not receive the HPV vaccine. RESULTS: HPV vaccination did not result in younger age at first intercourse. Women who received the HPV vaccine before or at the same age as sexual debut did not have more sexual partners than did non-vaccinees. Non-use of contraception during first intercourse was more common among non-vaccinees than among HPV vaccinees. The results were similar for organized catch-up and opportunistic vaccinees. CONCLUSION: Women who received the HPV vaccine before or at the same age as sexual debut did not subsequently engage more in sexual risk taking behaviour than women who did not receive the HPV vaccine.