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There are several equations based on bioelectrical impedance analysis (BIA) to estimate with high precision appendicular skeletal muscle mass (ASM). However, most of the external validation studies have reported that these equations are inaccurate or biased when applied to different populations. Furthermore, none of the published studies has derived correction factors (CFs) in samples of community-dwelling older adults, and none of the published studies have assessed the influence of the dual-energy X-ray absorptiometry (DXA) model on the validation process. This study assessed the agreement between six BIA equations and DXA to estimate ASM in non-Caucasian older adults considering the DXA model and proposed a CF for three of them. This analysis included 547 non-institutionalized subjects over 60 years old from the northwest of Mexico who were physically independent and without cognitive impairment: 192 subjects were measured using DXA Hologic, while 355 were measured by DXA Lunar. The agreement between each of the equations and DXA was tested considering the DXA model used as a reference method for the design of each equation, using the Bland and Altman procedure, a paired t test, and simple linear regression as objective tests. This process was supported by the differences reported in the literature and confirmed in a subsample of 70 subjects measured with both models. Only six published BIA equations were included. The results showed that four equations overestimated ASM DXA , and two underestimated it ( p < 0.001, 95% CI for Kim's equation:-5.86--5.45, Toselli's:-0.51--0.15, Kyle's: 1.43-1.84, Rangel-Peniche's: 0.32-0.74, Sergi's: 0.83-1.23, and Yoshida's: 4.16-4.63 kg). However, Toselli's, Kyle's and Rangel-Peniche's equations were the only ones that complied with having a homogeneous bias. This finding allowed the derivation of CFs, which consisted of subtracting or adding the mean of the differences from the original equation. After estimating ASM applying the respective CF, the new ASM estimations showed no significant bias and its distribution remained homogeneously distributed. Therefore, agreement with DXA in the sample of non-Caucasian was achieved. Adding valid CFs to some BIA equations allowed to reduce the bias of some equations, making them valid to estimate the mean values of ASM at group level., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Cáñez-Ríos, Esparza-Romero, González-Arellanes, Ramírez-Torres, Figueroa-Pesqueira, Urquidez-Romero, Rangel-Peniche and Alemán-Mateo.)

Despite that many image encryption systems based on chaotic or hyperchaotic systems have been proposed to protect different kinds of information, it has been crucial to achieve as much security as possible in such systems. In this sense, we numerically implement a known image encryption system with some variants, making special emphasis when two operations are considered in the scrambling stage. The variants of such an encryption system are based on some hyperchaotic systems, which generated some substitution boxes and the keys of the system. With the aim to have a more complete evaluation, some internal stages of the image encryption scheme have been evaluated by using common statistical tests, and also the scaling behavior of the encrypted images has been calculated by means of a two-dimensional detrended fluctuation analysis (2D-DFA). Our results show that the image encryption systems that include two operations or transformations in the scrambling stage present a better performance than those encryption systems that consider just one operation. In fact, the 2D-DFA approach was more sensitive than some common statistical tests to determine more clearly the impact of multiple operations in the scrambling process, confirming that this scaling method can be used as a perceptual security metric, and it may contribute to having better image encryption systems.

Background: Variation in the prevalence of sarcopenia is related to the skeletal muscle index cutoff points applied. The objective of this pilot study was to examine the recruitment process for testing different sarcopenia definitions (ASMI cutoffs) in older Mexican adults. It explored whether the prevalence of sarcopenia decreased by applying ethnic- and gender-specific, DXA-derived appendicular skeletal muscle index (ASMI)-cutoff points in the definitions, as well as some associated factors in a sample of community-dwelling older Mexican people., Methods: This is a pilot feasibility study that included a convenience sample of 217 community-dwelling older adults. Volunteers underwent DXA measurements and an assessment of functional status based on hand grip strength and physical performance. Six definitions were formed based on the 2010 EWGSOP criteria, but using different cutoff points for each of the three components, including regional cutoff points for ASMI derived from young Mexican adults. Several risk factors for sarcopenia were also assessed., Results: The prevalence of sarcopenia varied according to the different definitions applied. The lowest level was found with the definition that applied regional ASMI-cutoff points ( p < 0.01). The sarcopenic older adults had significant lower body weight, fat mass, and fat-free mass (FFM) than the nonsarcopenic subjects. The risk of sarcopenia increased with age and low FFM ( p < 0.001)., Conclusion: The present study demonstrates the feasibility of the main study, and our data support the notion that using regional ASMI cutoff points resulted in a low prevalence of sarcopenia. Therefore, it is preferable to estimate the prevalence of this condition using ethnic- and gender-specific cutoff points and to explore associated factors such as low FFM., Competing Interests: On behalf of all authors, the corresponding author states that there are no conflicts of interest., (Copyright © 2020 Heliodoro Alemán-Mateo et al.)

Background: Oral anticoagulants (OAC) such as vitamin K antagonists (VKA) and direct-acting OACs (DOAC) remain the mainstay for prevention of cardioembolic stroke. The influence of previous OAC treatment on stroke severity and outcomes is not well stablished. We compared patients with incident cardioembolic strokes according to pre-stroke treatment., Methods: Retrospective observational study of patients with cardioembolic stroke. Demographic data, vascular risk factors, pre-stroke treatments, reperfusion therapies and outcomes were analyzed. Propensity score matching of baseline characteristics was used to compare case-control samples across different treatment groups: adequate OAC vs no OAC; inadequate VKA vs no OAC; adequate VKA vs inadequate VKA; adequate VKA vs DOAC., Results: 462 patients (76 ± 11.6 years) included. 255 (55%) had a known major cardioembolic source, but only 151 (59%) of them were under OAC upon admission (127 VKA, 24 DOAC). Four patients received VKA for other reasons. Of those taking VKA, 91 (69%) had an inadequate anticoagulation. After propensity score matching, we found no significant differences in stroke severity across the different groups. Patients receiving DOAC had lower mortality at 3 months (8% vs 33%, p = .033) and higher successful recanalization rates after thrombectomy (100% vs 25%, p = .033) compared with adequate VKA anticoagulation., Conclusions: DOAC treatment significantly reduced mortality at three months compared with adequate VKA anticoagulation. Further studies are needed to confirm its influence on endovascular thrombectomy outcomes., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Background: Impaired physical performance (IPP) and physical disability (PD) are two serious public health problems in older adult populations worldwide. While studies show that changes in body composition are important risk factors for developing these conditions, there is little evidence that the fat-free mass (FFM) and fat mass (FM) indices (FFMI and FMI, respectively) are associated with IPP in older men and women. This study assessed the association among FFMI, FMI, and IPP using Short Physical Performance Battery (SPPB) in Mexican men and women aged over 60 years., Methods: This cross-sectional study included 217 older people (men 34.6%, women 65.4%; 60-92 years). FFM and FM were assessed by dual X-ray absorptiometry, assuming a two-compartment model. FFM and FM were adjusted by height squared and the indices were obtained. After assessment of physical performance by SPPB, subjects with scores ≤6 were classified as having IPP. Associations were tested by multiple logistic regression analysis in separated models., Results: IPP prevalence was 14.3%. Women were affected more than men. Regression analysis showed no significant association between FFMI and IPP, but FMI was strongly-associated, as for each unit increase in FMI, the risk of IPP rose significantly (OR: 1.14), and this result remained significant after adjusting for age, comorbidity, polypharmacy, and the appendicular skeletal muscle mass index (OR: 1.23; p ≤ 0.001). These results emphasize the importance of preventing increases in FM and avoiding overweight and obesity in older men and women., (Copyright © 2018 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.)

The epidemiology of community-acquired bacterial meningitis (CABM) in adults has changed significantly in the past several years. Despite substantial improvement in patient care, CABM remains a major cause of morbidity and mortality. Thus, new prognostic factors could help improve patient stratification. We conducted a multicenter retrospective study to determine the clinical pattern of CABM in an urban area of Western Europe and to identify potential predictors of unfavorable prognosis and complicated course. Over a period of 6-8 years, 79 adult CABM cases were treated at three tertiary hospitals. A Glasgow Outcome Scale (GOS) score of ≤4 was defined as unfavorable outcome. Predictors of unfavorable prognosis or complicated course were identified through logistic-regression analysis. S. pneumoniae was the most frequent pathogen (34%). 82% of patients exhibited at least two of five signs, including fever, neck stiffness, altered mental status, headache and nausea. Almost 50% presented focal neurological deficits; the overall mortality rate was 15%. In the multivariate analysis, risk factors for an unfavorable outcome included a GCS score of ≤13, female sex, and etiology by L. monocytogenes and gram-negative bacilli. However, risk factors for systemic complications were a GCS score of ≤13 and reduced platelet count, whereas C-Reactive Protein (CRP) increase was associated with a higher rate of neurological complications. Patients with non-pneumococcal CABM were more prone to an unfavorable outcome, probably because of underutilization of empiric ampicillin in patients at risk of listeriosis and because the suspicion of pneumococcal infection was facilitated by the existence of otitis and the higher yield of Gram's stain. Patients presenting a GCS of ≤13, thrombocytopenia and/or increased CRP, may benefit from more aggressive care to avoid in-hospital complications and neurological sequelae.

Background: Mexico is a country that is rich in ethnicity and cultural diversity, divided into three well-defined socioeconomic, ecological, and epidemiological areas. However, we do not know the influence that these factors may have on body composition. Therefore, this study was designed to assess body composition and compare appendicular skeletal muscle mass (ASM) in older people from two areas of the country., Methods: This is a cross-sectional study that included 430 subjects ≥60 years of age from northwestern and central Mexico. Body composition, including ASM, was measured by dual-energy X-ray absorptiometry, while anthropometry, handgrip strength, demographic variables, health status/chronic conditions, and energy expenditure data were all included., Results: Men and women from the northwestern region had 5.9 kg and 3.8 kg more body fat, respectively, and 3.9 kg more as a group than their counterparts from central Mexico ( p ≤ 0.0001). While there were no significant differences across gender or region in terms of ASM, the older subjects from central Mexico had a significantly higher ASM index (ASMI) than the sample from the northwest. When ASM was adjusted for age, body weight, height, health status/chronic conditions, estimated energy expenditure, and demographic variables, the subjects from central Mexico had significantly higher adjusted mean values of ASM and ASMI than their counterparts from the northwest., Conclusion: Older people from two regions of Mexico had significantly different estimates of body composition. Our findings highlight the importance of regionalizing estimates of ASM and ASMI if they are to be used for diagnostic purposes. It is also important to emphasize that appendicular skeletal muscle mass, or the ASM index, should be adjusted for other associated biological variables.

Methylmercury, a potent environmental pollutant responsible for fatal food poisoning, blocked calcium channels of bovine chromaffin cells in a time- and concentration-dependent manner with an IC50 of 0.93 μM. This blockade was not reversed upon wash-out and was greater at more depolarising holding potentials (i.e. 21 % at -110 mV and 60 % at -50 mV, after 3 min perfusion with methylmercury). In ω-toxins-sensitive calcium channels, methylmercury caused a higher blockade of I Ba than in ω-toxins-resistant ones, in which a lower blockade was detected. The sodium current was also blocked by acute application of methylmercury in a time- and concentration-dependent manner with an IC50 of 1.05 μM. The blockade was not reversed upon wash-out of the drug. The drug inhibited sodium current at all test potentials and shows a shift of the I-V curve to the left of about 10 mV. Intracellular dialysis with methylmercury caused no blockade of calcium or sodium channels. Voltage-dependent potassium current was not affected by methylmercury. Calcium- and voltage-dependent potassium current was also drastically depressed. This blockade was related to the prevention of Ca(2+) influx through voltage-dependent calcium channels coupled to BK channels. Under current-clamp conditions, the blockade of ionic current present during the generation and termination of action potentials led to a drastic alteration of cellular excitability. The application of methylmercury greatly reduced the shape and the number of electrically evoked action potentials. Taken together, these results point out that the neurotoxic action evoked by methylmercury may be associated to alteration of cellular excitability by blocking ionic currents responsible for the generation and termination of action potentials.

The aim of this paper is to describe metabolic and endocrine alterations in the male, partners of infertile couples. One hundred and six consecutive men were taken in order to analyze their serum samples. Each serum sample was analyzed by duplicate for luteinizing hormone (LH), follicle-stimulating hormone (FSH), estradiol (E2), free-testosterone (T), 17 alpha-hydroxyprogesterone (17OHP), androstenedione (A), dehydroepiandrosterone-sulphate (DHEA-S), prolactin (PRL), insulin, glucose, total cholesterol and triclylcerides. The data analysis evidenced different metabolic or endocrine alterations in the group. A dysplipidemia incidence of 65% was found (isolated hypercholesterolemia, isolated triglyceridemia or both), where 80% of these patients were younger than 40 years. There was no correlation with obesity, overweight any endocrine alteration and the type of sperm alterations. There was a positive correlation between E2 and FSH (r = 0.67, p < 0.0001) in the group of 106 patients, which remained significant in the group of hyperestrogenic men (n = 27, r = 0.68, p < 0.0001), but not in men with normal serum estrogen levels (n = 79, r = 0.10, NS). Other alterations: obesity in 18%, overweight in 30.2%, diabetes mellitus 4.7%, glucose intolerance 15%, hypertension 26% (14/53), hypergonadotropic hypogonadism 3.8% (one of them with an Emty Sella syndrome). Unexpectedly only nine patients (8.4%) out of the 106 consecutive patients recluted did not have any of the metabolic or endodrine abnormalities here described. These are more significant since 83% of the patients are younger than 40 years. The most interesting non previously described finding was the positive correlation observed between E2 and FSH when estradiol levels exceeds 50 pg/mL.