CYP121, the cytochrome P450 enzyme in that catalyzes a single intramolecular C-C cross-linking reaction in the biosynthesis of mycocyclosin, is crucial for the viability of this pathogen. This C-C coupling reaction represents an expansion of the activities carried out by P450 enzymes distinct from oxygen insertion. Although the traditional mechanism for P450 enzymes has been well studied, it is unclear whether CYP121 follows the general P450 mechanism or uses a different catalytic strategy for generating an iron-bound oxidant. To gain mechanistic insight into the CYP121-catalyzed reaction, we tested the peroxide shunt pathway by using rapid kinetic techniques to monitor the enzyme activity with its substrate dicyclotyrosine (cYY) and observed the formation of the cross-linked product mycocyclosin by LC-MS. In stopped-flow experiments, we observed that cYY binding to CYP121 proceeds in a two-step process, and EPR spectroscopy indicates that the binding induces active site reorganization and uniformity. Using rapid freeze-quenching EPR, we observed the formation of a high-spin intermediate upon the addition of peracetic acid to the enzyme-substrate complex. This intermediate exhibits a high-spin ( = 5/2) signal with g values of 2.00, 5.77, and 6.87. Likewise, iodosylbenzene could also produce mycocyclosin, implicating compound I as the initial oxidizing species. Moreover, we also demonstrated that CYP121 performs a standard peroxidase type of reaction by observing substrate-based radicals. On the basis of these results, we propose plausible free radical-based mechanisms for the C-C bond coupling reaction.

IMPORTANCEEvidence is needed regarding the introduction of high-risk human papillomavirus (hrHPV) testing into China's national cervical cancer screening program.OBJECTIVE To evaluate hrHPV testing as a new screening modality for the national program. DESIGN, SETTING, AND PARTICIPANTSThis population-based, multicenter, open-label, randomized clinical trial took place across 20 primary health care centers in urban and rural areas across China. At least 3000 women aged 35 to 64 years per site were invited to participate, for a total of 60 732 women evaluated.INTERVENTIONS At baseline, women were randomly assigned to cytology, hrHPV testing, or visual inspection with acetic acid and Lugol iodine (VIA/VILI) (rural only). Women who tested positive for hrHPV were randomized into cytology-triage, VIA/VILI-triage (rural only), or direct colposcopy arms. Regarding primary or triaging tests, women with cytological abnormalities or who tested positive with VIA/VILI were referred to colposcopy. After 24 months, combined screening of cytology, hrHPV testing, and VIA/VILI was performed, and all women with positive results were referred to colposcopy. MAIN OUTCOMES AND MEASURESThe primary outcomes were cervical intraepithelial neoplasia grade 2 or worse (CIN2+) and CIN3+ yields. The secondary outcome was colposcopy referral rate.RESULTS A total of 60 732 women were included in this study, with median (interquartile range) age of 47 (41-52) years. Among urban women, 8955 were randomized to cytology and 18 176 to hrHPV genotyping; among rural women, 11 136 were randomized to VIA/VILI, 7080 to cytology, and 15 385 to hrHPV testing. Participants who tested positive for hrHPV with direct colposcopy had higher risk ratios for disease yields at baseline (urban hrHPV vs cytology, CIN2+ 2.2 [95% CI, 1.6-3.2] and CIN3+ 2.0 [95% CI, 1.2-3.3]; rural hrHPV vs cytology, 2.6 [95% CI, 1.9-4.0] and 2.7 [95% CI, 2.0-3.6]; rural hrHPV vs VIA/VILI, 2.0 [95% CI, 1.6-2.3] and 2.3 [95% CI, 1.8-3.1]). At 24 months, baseline-negative women in the hrHPV arm had significantly lower risk ratios than those with cytology, or VIA/VILI for CIN2+ (0.3 [95% CI, 0.2-0.5], 0.3 [95% CI, 0.2-0.6]) and CIN3+ (0.3 [95% CI, 0.1-0.6], 0.4 [95% CI, 0.2-0.8]) in rural sites. The colposcopy referral rate for hrHPV-positive rural women was reduced to 2.8% by cytology triage, with significantly higher CIN2+ yields than cytology (2.1 [95% CI, 1.3-2.6]) or VIA/VILI arm (1.6 [95% CI, 1.03-2.1]). Genotyping for hrHPV with cytology triage significantly reduced the colposcopy referral rate compared with cytology (0.8 [95% CI, 0.7-0.9]) for urban women. CONCLUSIONS AND RELEVANCEIn this randomized clinical trial, testing for hrHPV was an effective primary screening method in primary health care centers. Incorporating hrHPV testing (polymerase chain reaction-based for urban areas, hybrid capture-based for rural areas) into China's national screening program is reasonable.

A highly chemically and thermally stable mesoporous hydrogen-bonded organic framework with a high surface area and a large pore volume has been rationally designed and constructed.

This study assessed the cost-effectiveness of a new, rapid human papillomavirus (HPV)-DNA screening test for cervical cancer prevention in the high-risk region of Shanxi, China. Using micro-costing methods, we estimated the resources needed to implement preventive strategies using cervical cytology or HPV-DNA testing, including the Hybrid Capture 2 (hc2) test (QIAGEN Corp., Gaithersburg, MD) and the rapid HPV-DNA careHPV TM test (QIAGEN). Data were used in a previously published model and empirically calibrated to country-specific epidemiological data. Strategies differed by initial test, targeted age, frequency of screening, number of clinic visits required (1, 2 or 3) and service delivery setting (national, county and township levels).Outcomes included lifetime risk of cancer, years of life saved (YLS), lifetime costs and incremental cost-effectiveness ratios (cost per YLS). For all screening frequencies, the most efficient strategy used 2-visit rapid HPV-DNA testing at the county level, including screening and diagnostics in the first visit, and treatment in the second visit. Screening at ages 35, 40 and 45 reduced cancer risk by 50% among women compliant with all 3 screening rounds, and was US$ 150 per YLS, compared with this same strategy applied twice per lifetime. This would be considered very cost-effective evaluated against China's percapita gross domestic product (US$ 1,702). By enhancing the linkage between screening and treatment through a reduced number of visits, rapid HPV-DNA testing 3 times per lifetime is more effective than traditional cytology, and is likely to be cost-effective in high-risk regions of China.Cervical cancer affects millions of individuals worldwide and is a leading cause of cancer death among women in developing countries. 1 Although China registers a low average incidence of cervical cancer compared to many other regions of the world, the overall burden is large due to the size of the country's population. Moreover, there is considerable heterogeneity in terms of risk, with cervical cancer mortality rates in poor provinces such as Shanxi and Gansu exceeding 30 cases per 100,000. 2 Data available from one survey indicate that the prevalence of carcinogenic types of human papillomavirus (HPV) is 20.8% among 35-to 50-year-old women. 3Since a national cervical cancer prevention program does not exist, most women have not been screened. 2 Cervical cancer has been reduced in countries able to implement organized secondary prevention programs that screen women with cytology at regular closely spaced intervals. 4 Unfortunately, the requirement for high-quality laboratory and cytotechnologist support, coupled with the need for multiple visits, has proven difficult to implement in lowresource settings. Screening approaches that use HPV-DNA testing may prove more practical when incorporated into strategies less dependent on existing laboratory infrastructure and requiring fewer visits. 5,6 Most recently, a randomized trial in Osmanabad district in India demonstrated a single round of HP...

Background An increasing number of undergraduate students in China have been reported to have psychological problems. In response to the COVID-19 pandemic, a series of preventive and control measures were implemented, which undoubtedly worsened their psychological health. Coping style and social support were probably important factors that affected the psychological well-being of undergraduate students during the pandemic. This study aimed to explore the effects of coping style and perceived social support on the psychological well-being of college students and relevant risk factors. Methods This cross-sectional study was performed in February and March of 2020 by distributing an online questionnaire among undergraduate students from seven geographical regions across China. The questionnaire included sociodemographic information; the 21-item Depression, Anxiety and Stress Scale (DASS-21); the Perceived Social Support Scale (PSSS); and the Simplified Coping Style Questionnaire (SCSQ). For the analyses, t-tests, one-way analysis of variance (ANOVA), the Kruskal–Wallis test and multiple linear regression were utilized. The level of significance was set at P < 0.05. Results Among 3113 college students, the rates of anxiety, depression and stress symptoms were 13.3, 15.4 and 6.8%, respectively. Increased rates of current smoking and drinking (5.5 and 25.2%, respectively) among undergraduates were identified. The results indicated that the PSSS subscales and SCSQ subscales were significantly associated with DASS-21 scores (P < 0.001). Multiple linear regression analysis showed that active coping style and family support were protective factors while passive coping style could aggravate psychological problems among participants (P < 0.001). Conclusions A remarkable number of college students adopted passive coping strategies to cope with negative feelings, such as smoking and drinking, which were detrimental to their mental health. In contrast, active coping strategies helped improve their psychological well-being. Moreover, family support was particularly important for maintaining their mental health and ameliorating mental health challenges in this major health crisis. Consequently, suitable psychointervention, routine screening for risk behaviors, and provision of further social support are needed for undergraduate students in the COVID-19 pandemic or other emergency public health events.