INTRODUCTIONIn Mexico, a new COVID-19 case definition was released on 24 March 2020, this definition is no different from the one used for epidemiological surveillance of influenza-like illness since 2009. We aim to evaluate the effectiveness of the COVID-19 suspected case definition in identifying SARS-CoV-2 infection in Tijuana, a US-border city in Mexico. METHODS A cross-sectional database study was conducted, including entries from 11 March to 1 May 2020. COVID-19 case definition was compared to RT-PCR results using 2×2 tables to estimate sensitivity, specificity, PPV, NPV, accuracy and likelihood ratios (LR). Categorical variables were analyzed using χ 2 test. Stratification by gender, age group, history of chronic disease and severity of presentation was performed to control for confounding. RESULTS From a total of 10216 entries, 897 patients with results from RT-CPR for SARS-CoV-2 were included. There was no significant association between COVID-19 case definition and RT-PCR result (χ 2 =0.750, df=1, p=0.386). A sensitivity of 87.45%, specificity of 10.61%, PPV of 61.69%, and NPV of 33.96% were calculated, with an overall accuracy of 58.42%, LR+ was 0.98 and LR-was 1.18. Stratifying by age, homogeneity of OR=0.024 showed an association between case definition and test result particularly among those aged 16-39 years (p=0.014). Only 4 individual symptoms had a statistical association with RT-PCR result. These were dyspnea (p<0.001), odynophagia (p<0.001), rhinorrhea (p<0.001) and fever (p=0.008). CONCLUSIONS Satisfying criteria for COVID-19 case definition neither showed a significant association nor is it a powerful predictor for SARS-CoV-2 infection among the study population. However, this COVID-19 case definition better identifies those cases in those aged 16-39 years, suggesting a possible relation between the type of the clinical presentation and age.

Background: Hypertension is still a growing public health problem in Mexico. An estimated 151% increase in the number of individuals with hypertension is expected for 2050 if actions are not taken in the country. The aim of this study is to describe hypertension awareness, treatment, control and its associated factors in participants of an opportunistic medical student-led blood pressure screening campaign in Mexico. Methods: A cross-sectional study, using convenience sampling was performed, including participants aged 18 years and older from 15 Mexican states. Each participant completed a questionnaire about risk factors and had three BP measurements taken. Hypertension was defined as ≥140/90 mmHg. Multiple imputation with linear regression was performed where data was missing. Results: From a population of 2 545 participants, 623 (24.5%) participants had hypertension. Of those with hypertension, 81.9% had a previous diagnosis of hypertension and only 16.1% were not on medication at the time of screening; 61% were controlled, 121% were uncontrolled patients and 18% were not aware they had hypertension. High marginalization was found to have the biggest proportion of uncontrolled cases (33%), while the number of unaware hypertensives in very low marginalization states doubled the national figure. More than half the participants taking antihypertensive agents were on a single medication, achieving control in almost 8 in 10 patients. Conclusion: It is important to continue making and supporting awareness raising campaigns in different settings across the country to generate more evidence and lead to better programs for improving hypertension detection in Mexico.

Treatment of rifampin-resistant and multidrug-resistant tuberculosis in pregnant women is more complicated since little is known about the safety of second-line antituberculosis drugs during pregnancy and lactation. Drug-resistant tuberculosis, not having many options in the past, has been treated with regimens that include drugs with teratogenic potentials, such as thioamides and second-line injectables. Currently, there are new oral drugs, including bedaquiline, for the treatment of drugresistant disease; however, the safety of bedaquiline during pregnancy and lactation has not been satisfactorily demonstrated so far. We report the first case in Mexico treated with a regimen that includes bedaquiline for multidrug-resistant tuberculosis during pregnancy, with favorable results, and without maternal-fetal complications.

Chromatin maintenance and remodeling are processes that take place alongside DNA repair, replication, or transcription to ensure the survival and adaptability of a cell. The environment and the needs of the cell dictate how chromatin is remodeled; particularly where and which histones are deposited, thus changing the canonical histone array to regulate chromatin structure and gene expression. Chromatin is highly dynamic, and histone variants and their chaperones play a crucial role in maintaining the epigenetic regulation at different genomic regions. Despite the large number of histone variants reported to date, studies on their roles in physiological processes and pathologies are emerging but continue to be scarce. Here, we present recent advances in the research on histone variants and their chaperones, with a focus on their importance in molecular mechanisms such as replication, transcription, and DNA damage repair. Additionally, we discuss the emerging role they have in transposable element regulation, aging, and chromatin remodeling syndromes. Finally, we describe currently used methods and their limitations in the study of these proteins and highlight the importance of improving the experimental approaches to further understand this epigenetic machinery.