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•DNA glycosylases remove damaged bases, initiating BER, but mechanisms for many are poorly defined.•MBD4, of the HhH superfamily, repairs mutagenic G·T mispairs arising from ...5-methylcytosine deamination.•New structures of enzyme-DNA complexes, at three stages of catalysis, illuminate the MBD4 mechanism.•Our structural and biochemical findings inform the role of a catalytic Asp conserved in HhH glycosylases.•Detailed snapshots of metal-bound HhH motifs inform how these ubiquitous elements mediate DNA binding.
DNA glycosylases remove damaged or modified nucleobases by cleaving the N-glycosyl bond and the correct nucleotide is restored through subsequent base excision repair. In addition to excising threatening lesions, DNA glycosylases contribute to epigenetic regulation by mediating DNA demethylation and perform other important functions. However, the catalytic mechanism remains poorly defined for many glycosylases, including MBD4 (methyl-CpG binding domain IV), a member of the helix-hairpin-helix (HhH) superfamily. MBD4 excises thymine from G·T mispairs, suppressing mutations caused by deamination of 5-methylcytosine, and it removes uracil and modified uracils (e.g., 5-hydroxymethyluracil) mispaired with guanine. To investigate the mechanism of MBD4 we solved high-resolution structures of enzyme-DNA complexes at three stages of catalysis. Using a non-cleavable substrate analog, 2′-deoxy-pseudouridine, we determined the first structure of an enzyme-substrate complex for wild-type MBD4, which confirms interactions that mediate lesion recognition and suggests that a catalytic Asp, highly conserved in HhH enzymes, binds the putative nucleophilic water molecule and stabilizes the transition state. Observation that mutating the Asp (to Gly) reduces activity by 2700-fold indicates an important role in catalysis, but probably not one as the nucleophile in a double-displacement reaction, as previously suggested. Consistent with direct-displacement hydrolysis, a structure of the enzyme-product complex indicates a reaction leading to inversion of configuration. A structure with DNA containing 1-azadeoxyribose models a potential oxacarbenium-ion intermediate and suggests the Asp could facilitate migration of the electrophile towards the nucleophilic water. Finally, the structures provide detailed snapshots of the HhH motif, informing how these ubiquitous metal-binding elements mediate DNA binding.
There remains uncertainty about the impact of menopausal hormone therapy (MHT) on women's health. A systematic, comprehensive assessment of the effects on multiple outcomes is lacking. We conducted ...an umbrella review to comprehensively summarize evidence on the benefits and harms of MHT across diverse health outcomes. We searched MEDLINE, EMBASE, and 10 other databases from inception to November 26, 2017, updated on December 17, 2020, to identify systematic reviews or meta-analyses of randomized controlled trials (RCTs) and observational studies investigating effects of MHT, including estrogen-alone therapy (ET) and estrogen plus progestin therapy (EPT), in perimenopausal or postmenopausal women in all countries and settings. All health outcomes in previous systematic reviews were included, including menopausal symptoms, surrogate endpoints, biomarkers, various morbidity outcomes, and mortality. Two investigators independently extracted data and assessed methodological quality of systematic reviews using the updated 16-item AMSTAR 2 instrument. Random-effects robust variance estimation was used to combine effect estimates, and 95% prediction intervals (PIs) were calculated whenever possible. We used the term MHT to encompass ET and EPT, and results are presented for MHT for each outcome, unless otherwise indicated. Sixty systematic reviews were included, involving 102 meta-analyses of RCTs and 38 of observational studies, with 102 unique outcomes. The overall quality of included systematic reviews was moderate to poor. In meta-analyses of RCTs, MHT was beneficial for vasomotor symptoms (frequency: 9 trials, 1,104 women, risk ratio RR 0.43, 95% CI 0.33 to 0.57, p < 0.001; severity: 7 trials, 503 women, RR 0.29, 95% CI 0.17 to 0.50, p = 0.002) and all fracture (30 trials, 43,188 women, RR 0.72, 95% CI 0.62 to 0.84, p = 0.002, 95% PI 0.58 to 0.87), as well as vaginal atrophy (intravaginal ET), sexual function, vertebral and nonvertebral fracture, diabetes mellitus, cardiovascular mortality (ET), and colorectal cancer (EPT), but harmful for stroke (17 trials, 37,272 women, RR 1.17, 95% CI 1.05 to 1.29, p = 0.027) and venous thromboembolism (23 trials, 42,292 women, RR 1.60, 95% CI 0.99 to 2.58, p = 0.052, 95% PI 1.03 to 2.99), as well as cardiovascular disease incidence and recurrence, cerebrovascular disease, nonfatal stroke, deep vein thrombosis, gallbladder disease requiring surgery, and lung cancer mortality (EPT). In meta-analyses of observational studies, MHT was associated with decreased risks of cataract, glioma, and esophageal, gastric, and colorectal cancer, but increased risks of pulmonary embolism, cholelithiasis, asthma, meningioma, and thyroid, breast, and ovarian cancer. ET and EPT had opposite effects for endometrial cancer, endometrial hyperplasia, and Alzheimer disease. The major limitations include the inability to address the varying effects of MHT by type, dose, formulation, duration of use, route of administration, and age of initiation and to take into account the quality of individual studies included in the systematic reviews. The study protocol is publicly available on PROSPERO (CRD42017083412). MHT has a complex balance of benefits and harms on multiple health outcomes. Some effects differ qualitatively between ET and EPT. The quality of available evidence is only moderate to poor.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
IMPORTANCE: Increasing access to care may be insufficient to improve the health of patients with diabetes mellitus and unmet basic needs (hereinafter referred to as material need insecurities). How ...specific material need insecurities relate to clinical outcomes and the use of health care resources in a setting of near-universal access to health care is unclear. OBJECTIVE: To determine the association of food insecurity, cost-related medication underuse, housing instability, and energy insecurity with control of diabetes mellitus and the use of health care resources. DESIGN, SETTING, AND PARTICIPANTS: Cross-sectional data were collected from June 1, 2012, through October 31, 2013, at 1 academic primary care clinic, 2 community health centers, and 1 specialty center for the treatment of diabetes mellitus in Massachusetts. A random sample of 411 patients, stratified by clinic, consisted of adults (aged ≥21 years) with diabetes mellitus (response rate, 62.3%). MAIN OUTCOMES AND MEASURES: The prespecified primary outcome was a composite indicator of poor diabetes control (hemoglobin A1c level, >9.0%; low-density lipoprotein cholesterol level, >100 mg/dL; or blood pressure, >140/90 mm Hg). Prespecified secondary outcomes included outpatient visits and a composite of emergency department (ED) visits and acute care hospitalizations (ED/inpatient visits). RESULTS: Overall, 19.1% of respondents reported food insecurity; 27.6%, cost-related medication underuse; 10.7%, housing instability; 14.1%, energy insecurity; and 39.1%, at least 1 material need insecurity. Poor diabetes control was observed in 46.0% of respondents. In multivariable models, food insecurity was associated with a greater odds of poor diabetes control (adjusted odds ratio OR, 1.97 95% CI, 1.58-2.47) and increased outpatient visits (adjusted incident rate ratio IRR, 1.19 95% CI, 1.05-1.36) but not increased ED/inpatient visits (IRR, 1.00 95% CI, 0.51-1.97). Cost-related medication underuse was associated with poor diabetes control (OR, 1.91 95% CI, 1.35-2.70) and increased ED/inpatient visits (IRR, 1.68 95% CI, 1.21-2.34) but not outpatient visits (IRR, 1.07 95% CI, 0.95-1.21). Housing instability (IRR, 1.31 95% CI, 1.14-1.51) and energy insecurity (IRR, 1.12 95% CI, 1.00-1.25) were associated with increased outpatient visits but not with diabetes control (OR, 1.10 95% CI, 0.60-2.02 and OR, 1.27 95% CI, 0.96-1.69, respectively) or with ED/inpatient visits (IRR, 1.49 95% CI, 0.81-2.73 and IRR, 1.31 95% CI, 0.80-2.13, respectively). An increasing number of insecurities was associated with poor diabetes control (OR for each additional need, 1.39 95% CI, 1.18-1.63) and increased use of health care resources (IRR for outpatient visits, 1.09 95% CI, 1.03-1.15; IRR for ED/inpatient visits, 1.22 95% CI, 0.99-1.51). CONCLUSIONS AND RELEVANCE: Material need insecurities were common among patients with diabetes mellitus and had varying but generally adverse associations with diabetes control and the use of health care resources. Material need insecurities may be important targets for improving care of diabetes mellitus.
There is uncertainty about the role of hormonal replacement therapy (HRT) in the development of asthma.
We investigated whether use of HRT and duration of use was associated with risk of development ...of asthma in perimenopausal and postmenopausal women.
We constructed a 17-year (from January 1, 2000, to December 31, 2016) open cohort of 353,173 women (aged 46-70 years) from the Optimum Patient Care Database, a longitudinal primary care database from across the United Kingdom. HRT use, subtypes, and duration of use; confounding variables; and asthma onset were defined by using the Read Clinical Classification System. We fitted multilevel Cox regression models to estimate hazard ratios (HRs) with 95% CIs.
During the 17-year follow-up (1,340,423 person years), 7,614 new asthma cases occurred, giving an incidence rate of 5.7 (95% CI = 5.5-5.8) per 1,000 person years. Compared with nonuse of HRT, previous use of any (HR = 0.83; 95% CI = 0.76-0.88), estrogen-only (HR = 0.89; 95% CI = 0.84-0.95), or combined estrogen and progestogen (HR = 0.82; 95% CI = 0.76-0.88) HRT was associated with a reduced risk of asthma onset. This was also the case with current use of any (HR = 0.79; 95% CI = 0.74-0.85), estrogen-only (HR = 0.80; 95% CI = 0.73-0.87), and combined estrogen and progestogen (HR = 0.78; 95% CI = 0.70-0.87) HRT. Longer duration of HRT use (1-2 years HR = 0.93; 95% CI = 0.87-0.99; 3-4 years HR = 0.77; 95% CI = 0.70-0.84; and ≥5 years HR = 0.71; 95% CI = 0.64-0.78) was associated with a dose-response reduced risk of asthma onset.
We found that HRT was associated with a reduced risk of development of late onset asthma in menopausal women. Further cohort studies are needed to confirm these findings.
To the Editor: Asthma and allergy are more common in males than in females during early childhood, but the incidence, severity, and impact on quality of life are greater in postpubertal females than ...in males.1,2 Female sex steroid hormones may partly explain these differences.1,2 In 2 previous systematic reviews, early menarche (<12 years) was associated with an increased asthma risk,3 whereas no significant association was found between menopause and asthma, although subgroup analyses indicated an increased risk in postmenopausal women using hormone replacement therapy (HRT).4 Consideration of other hormonal factors, along with the full spectrum of relevant outcomes, is necessary for a comprehensive appreciation of the underlying evidence base. Secondary outcomes included self-reported atopic dermatitis/eczema, wheeze, allergic rhinitis, and food allergy; measures of lung function using spirometry; and specific/total IgE assessed using serum samples. Compared with the premenopausal period, onset of menopause was associated with increased risk of current asthma (OR, 1.25; 95% CI, 1.04-1.51) (Fig E3), and with an increased risk of new-onset asthma in one study,E68 but a decreased risk in another.E69 Each type of menopause (natural vs surgical) was associated with an increased risk of current asthma in one study,E36 but a decreased risk of new-onset asthma in another study.E69 One study found a significantly higher exacerbation rate in women who developed asthma around the time of their menopause than in women with preexisting asthma.E15 Another found that exacerbations were reported most frequently by women in early postmenopause, followed by those in late postmenopause or the menopausal transition, and those who were premenopausal; however, no significance tests were performed.E68 This study found the same pattern of reporting for current asthma medication use.E68 Onset of menopause was associated with increased risk of current wheeze (OR, 1.16; 95% CI, 1.05-1.30), but not current allergic rhinitis (OR, 0.94; 95% CI, 0.81-1.10) (Fig E3).Associations between exogenous sex hormones and risk of asthma and allergy Results of studies on use of hormonal contraceptives were mixed, with both increased and decreased risks reported across studies (data available on request). The associated P values for Egger test were as follows: menstruation P = .295; HRT P = .999; menarche P = .108; menopause P = .831; hormonal contraceptives P = .057.Appendix E1 MEDLINE search strategy—November 11, 2015 exp Puberty/or puberty.mp. exp Menarche/or menarche.mp. exp Menstruation/or exp Menstruation Disturbances/or menstruation.mp. exp Menopause, Premature/or exp Postmenopause/or menopause.mp. sex hormones.mp. or exp Gonadal Steroid Hormones/or exp Estrogens/or estrogens.mp. or exp Progesterone/or progesterone.mp. or Testosterone Congeners/or testosterone.mp. or exp Testosterone/or Testosterone Propionate/ exp Contraceptive Agents/or contraceptives.mp. or exp Contraceptives, Oral/or oral contraceptives.mp. or exp Contraceptives, Oral, Combined/or combined oral contraceptives.mp. or exp Medroxyprogesterone Acetate/or exp Contraceptive Agents, Female/or exp Contraceptives, Oral, Hormonal/or exp Contraception/or hormonal contraceptives.mp. or exp Ethinyl Estradiol/ exp Hormone Replacement Therapy/or exp Estradiol/or hormone replacement therapy.mp. 1 or 2 or 3 or 4 or 5 or 6 or 7 exp Asthma/or asthma.mp. wheeze.mp. exp Dermatitis, Atopic/or atopic eczema.mp. exp Hypersensitivity, Immediate/or exp Hypersensitivity/or atopy.mp. or allergy.mp. or atopic sensitisation.mp. or allergic sensitisation.mp. exp Rhinitis, Allergic, Seasonal/or exp Rhinitis, Allergic, Perennial/or exp Allergens/or allergic rhinitis.mp. exp Conjunctivitis, Allergic/or Rhinoconjunctivitis.mp. exp Conjunctivitis, Allergic/or Rhinoconjunctivitis.mp. exp Urticaria/or urticarial.mp. exp Angioedema/or angioedema.mp. exp Food Hypersensitivity/or food allergy.mp. exp Anaphylaxis/or anaphylaxis.mp. lung function.mp. airway function.mp. or exp Bronchial Hyperreactivity/ exp Forced Expiratory Volume/or forced expiratory volume in 1 second.mp. exp Peak Expiratory Flow Rate/or peak expiratory flow.mp. 9 or 10 or 11 or 12 or 13 or 14 or 15 or 16 or 17 or 18 or 19 or 20 or 21 or 22 or 23 8 and 24 limit 25 to female
The impact of hormone replacement therapy (HRT) on clinical outcomes in menopausal women is uncertain.
To investigate the association between use of HRT and severe asthma exacerbation in ...perimenopausal and postmenopausal women with asthma.
We used the Optimum Patient Care Research Database, a population-based longitudinal primary care database in the United Kingdom, to construct a 17-year (January 1, 2000, to December 31, 2016) cohort of perimenopausal and postmenopausal (46-70 years, N = 31,656) women. We defined use of HRT, its subtypes, and duration of HRT use. Severe asthma exacerbation was defined as an asthma-related hospitalization, emergency department visits due to asthma, and/or prescription of oral corticosteroids. Analyses were undertaken using multilevel mixed-effects Poisson regression.
At baseline, 22% of women were using any HRT, 11% combined HRT, and 11% estrogen-only HRT. Previous, but not current, use of any (incidence rate ratio IRR: 1.24, 95% confidence interval CI: 1.22-1.26), combined (IRR: 1.28, 95% CI: 1.25-1.31), and estrogen-only HRT (IRR: 1.18, 95% CI: 1.14-1.21), and longer duration (1-2 years: IRR: 1.16, 95% CI: 1.13-1.19; 3-4 years: IRR: 1.43, 95% CI: 1.38-1.48; 5+ years: IRR: 1.32, 95% CI: 1.28-1.36) of HRT use were associated with increased risk of severe asthma exacerbation compared with nonuse. The risk estimates were greater among lean women (body mass index BMI <25 kg/m2) than among heavier women (BMI 25-29.9 kg/m2 and ≥30 kg/m2) and higher among smokers than nonsmokers.
Use of HRT and subtypes, particularly previous, but not current, use and use for more than 2 years, is associated with an increased risk of severe asthma exacerbation in perimenopausal/postmenopausal women with established asthma. Lean women and smokers are at greater risk than heavier women and nonsmokers, respectively.
Community-based GeneXpert MTB/RIF testing may increase detection of prevalent TB in the community and improve rates of TB treatment completion.
We conducted a pilot randomized trial to evaluate the ...impact of GeneXpert screening on a mobile HIV testing unit. Adults (≥18y) underwent rapid HIV testing and TB symptom screening and were randomized to usual mobile unit care (providing sputum on the mobile unit sent out for GeneXpert testing) or the "Test & Treat TB" intervention with immediate GeneXpert testing. Symptomatic participants in usual care produced sputum that was sent for hospital-based GeneXpert testing; participants were contacted ~ 7 days later with results. In the "Test & Treat TB" intervention, HIV-infected or HIV-uninfected/TB symptomatic participants underwent GeneXpert testing on the mobile unit. GeneXpert+ participants received expedited TB treatment initiation, monthly SMS reminders and non-cash incentives. We assessed 6-month TB treatment outcomes.
4815 were eligible and enrolled; median age was 27 years (IQR 22 to 35). TB symptoms included cough (5%), weight loss (4%), night sweats (4%), and fever (3%). 42% of eligible participants produced sputum (intervention: 56%; usual care: 26%). Seven participants tested GeneXpert+, six in the intervention (3%, 95% CI 1%, 5%) and one in usual care (1%, 95% CI 0%, 6%). 5 of 6 intervention participants completed TB treatment; the GeneXpert+ participant in usual care did not.
GeneXpert MTB/RIF screening on a mobile HIV testing unit is feasible. Yield for GeneXpert+ TB was low, however, the "Test & Treat TB" strategy led to high rates of TB treatment completion.
This study was registered on November 21, 2014 at ClinicalTrials.gov ( NCT02298309 ).
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Despite well-described sex differences in asthma incidence, there remains uncertainty about the role of female sex hormones in the development of asthma.
We sought to investigate whether hormonal ...contraceptive use, its subtypes, and duration of use were associated with new-onset asthma in reproductive-age women.
Using the Optimum Patient Care Research Database, a UK national primary care database, we constructed an open cohort of 16- to 45-year-old women (N = 564,896) followed for up to 17 years (ie, January 1, 2000, to December 31, 2016). We fitted multilevel Cox regression models to analyze the data.
At baseline, 26% of women were using any hormonal contraceptives. During follow-up (3,597,146 person-years), 25,288 women developed asthma, an incidence rate of 7.0 (95% CI, 6.9-7.1) per 1000 person-years. Compared with nonuse, previous use of any hormonal contraceptives (hazard ratio HR, 0.70; 95% CI, 0.68-0.72), combined (HR, 0.70; 95% CI, 0.68-0.72), and progestogen-only therapy (HR, 0.70; 95% CI, 0.67-0.74) was associated with reduced risk of new-onset asthma. For current use, the estimates were as follows: any (HR, 0.63; 95% CI, 0.61-0.65), combined (HR, 0.65; 95% CI, 0.62-0.67), and progestogen-only therapy (HR, 0.59; 95% CI, 0.56-0.62). Longer duration of use (1-2 years: HR, 0.83; 95% CI, 0.81-0.86; 3-4 years: HR, 0.64; 95% CI, 0.61-0.67; 5+ years: HR, 0.46; 95% CI, 0.44-0.49) was associated with a lower risk of asthma onset than nonuse.
Hormonal contraceptive use was associated with reduced risk of new-onset asthma in women of reproductive age. Mechanistic investigations to uncover the biological processes for these observations are required. Clinical trials investigating the safety and effectiveness of hormonal contraceptives for primary prevention of asthma will be helpful to confirm these results.
Limited research has investigated the long-term effects of childhood emotional abuse on later forms of parenting. This study utilized a person-centered approach to explore the relation between ...retrospectively-reported maternal childhood emotional abuse and observed parenting behaviors during a conflict discussion. Data were collected from 53 caregiver-child dyads with children ages 8–11. Results of a model-based clustering procedure (
Mclust
; Fraley and Raftery
2006
) identified three parenting styles (negative, at-risk, positive) that were based on five observed parenting behaviors (emotion regulation, anger, hostility, psychological control, and psychological unavailability). Results indicated that higher levels of childhood emotional abuse were reported by women in the at-risk and negative parenting subgroups. Mothers in the negative parenting and at-risk parenting clusters exhibited greater levels of emotional abuse when compared to the positive parenting cluster. Possible implications are discussed, and results underscore the importance of emotionally abusive developmental experiences in the understanding of risk for maladaptive parenting behaviors.
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