Eumelanin and Pheomelanin Modelling in Optical Oximetry Using Pulse Oximetry (for 540 nm and 660 nm): DC Component.

Oximetry is used to quantify the presence of oxygen in soft tissues. It can be expressed as, for example, tissue oxygen saturation (StO), arterial oxygen saturation (SaO) and pulsatile oxygen saturation (SpO), among others. Non-invasive medical devices are used to estimate (SaO).

Glycine by enteral route does not improve major clinical outcomes in severe COVID-19: a randomized clinical pilot trial.

There is a worrying scarcity of drug options for patients with severe COVID-19. Glycine possesses anti-inflammatory, cytoprotective, endothelium-protective, and platelet-antiaggregant properties, so its use in these patients seems promising. In this open label, controlled clinical trial, inpatients with severe COVID-19 requiring mechanical ventilation randomly received usual care (control group) or usual care plus 0.

Trajectories of sleep duration and quality and their association with mild cognitive impairment, frailty, and all-cause mortality.

Objectives: To identify longitudinal trajectories of sleep duration and quality and estimate their association with mild cognitive impairment, frailty, and all-cause mortality.

Methods: We used data from three waves (2009, 2014, 2017) of the WHO Study on Global Aging and Adult Health in Mexico. The sample consisted of 2722 adults aged 50 and over.

Reference equations using segmented regressions for impulse oscillometry in healthy subjects aged 2.7-90 years.

Background: Published reference equations for impulse oscillometry (IOS) usually encompass a specific age group but not the entire lifespan. This may lead to discordant predicted values when two or more non-coincident equations can be applied to the same person, or when a person moves from one equation to the next non-convergent equation as he or she gets older. Thus, our aim was to provide a single reference equation for each IOS variable that could be applied from infancy to old age.

Lung function is related to salivary cytokines and hormones in healthy children. An exploratory cross-sectional study.

Pulmonary mechanics has been traditionally viewed as determined by lung size and physical factors such as frictional forces and tissue viscoelastic properties, but few information exists regarding potential influences of cytokines and hormones on lung function. Concentrations of 28 cytokines and hormones were measured in saliva from clinically healthy scholar children, purposely selected to include a wide range of body mass index (BMI). Lung function was assessed by impulse oscillometry, spirometry, and diffusing capacity for carbon monoxide, and expressed as z-score or percent predicted.

[Small airway: from definition to treatment].

The small airway, present since the origins of humanity and described barely a century ago, has recently been discovered as the anatomical site where inflammation begins in some obstructive lung diseases, such as asthma and Chronic Obstructive Pulmonary Disease (COPD), per se. Small airway dysfuction was identified in up to 91% of asthmatic patients and in a large proportion of COPD patients. In subjects without pathology, small airway represent 98.

Altitude and Breathing during Sleep in Healthy Persons and Sleep Disordered Patients: A Systematic Review.

 The aim of this systematic review is to analyze the recent scientific evidence of the clinical effects of altitude on breathing during sleep in healthy persons and sleep disordered patients.  A search was carried out in PubMed and Scopus looking for articles published between January 1, 2010 and December 31, 2021, in English and Spanish, with the following search terms: "sleep disorders breathing and altitude". Investigations in adults and carried out at an altitude of 2000 meters above mean sea level (MAMSL) or higher were included.

Changes in Oxygenation Levels During Moderate Altitude Simulation (Hypoxia-Induced): A Pilot Study Investigating the Impact of Skin Pigmentation in Pulse Oximetry.

The current COVID-19 pandemic has shown us that the pulse oximeter is a key medical device for monitoring blood-oxygen levels non-invasively in patients with chronic or acute illness. It has also emphasised limitations in accuracy for individuals with darker skin pigmentation, calling for new methods to provide better measurements. The aim of our study is to identify the impact of skin pigmentation on pulse oximeter measurements.

Sex Differences in the Association Between Risk of Obstructive Sleep Apnea, Insomnia, and Frailty in Older Adults.

Purpose: To analyze the association between risk of obstructive sleep apnea (OSA), insomnia, sleepiness and self-assessed sleep duration with frailty in older adults.

Patients And Methods: Cross-sectional study with 1643 older adults (60 to 97 years old) who participated in round 6 (2019) of the Cohort of Obesity Sarcopenia and Obesity in Older Adults of the Mexican Institute of Social Security. The Berlin Questionnaire was used to assess risk of OSA, the Athens Insomnia Scale for insomnia, the Epworth Scale for sleepiness, and sleep duration by self-report.

Dietary patterns and sleep disorders in Mexican adults from a National Health and Nutrition Survey.

Given the high prevalence of multiple non-communicable chronic diseases in Mexico, the aim of the present study was to assess the association between dietary patterns and sleep disorders in a national representative sample of 5076 Mexican adults (20-59 years) from the 2016 National Health and Nutrition Survey. Through a cross-sectional study, we used the Berlin sleep symptoms questionnaire to estimate the proportion of adults with insomnia, obstructive sleep apnoea (OSA) and other related problems such as daytime symptoms and inadequate sleep duration. Dietary data were collected through a seven-day semi-quantitative food frequency questionnaire, and dietary patterns were determined through cluster analysis.

Clinical Markers of Chronic Hypoxemia in Respiratory Patients Residing at Moderate Altitude.

Supplemental oxygen (SO) increases survival in hypoxemic patients. In hypoxia, mammals respond by modulating O-sensitive transducers that stabilize the transcription factor hypoxia-inducible factor-1-alpha (HIF-1α), which transactivates the genes that govern angiogenesis and metabolic pathways. Residing at high altitudes exposes millions of people to hypoxemia with potential adverse consequences on their health.

Salivary concentrations of cytokines and other analytes in healthy children.

Background: Blood has been the usual biological fluid for measuring analytes, but there is mounting evidence that saliva may be also useful for detecting cytokines in a noninvasive way. Thus, in this study we aimed to determine concentration of cytokines and other analytes in saliva from a population of healthy children.

Methods: We collected un-stimulated whole saliva samples from clinically healthy children, and concentration of 17 cytokines and 12 other analytes were measured in supernatants.

Inspiratory Capacity and Vital Capacity of Healthy Subjects 9-81 Years of Age at Moderate-High Altitude.

Background: Measurements of inspiratory capacity (IC) and vital capacity (VC) are used to recognize dynamic hyperinflation, but appropriate reference values are required to achieve accurate clinical interpretations. Altitude above sea level is a potential determining factor for lung volumes, including IC and VC.

Objective: To describe IC and VC for healthy people who live in Mexico City at an altitude of 2,240 m above sea level.

Diffusing Capacity of the Lung for Carbon Monoxide in Mexican/Latino Children. Quality Control and Reference Values.

Rationale: Single-breath diffusing capacity of the lung for carbon monoxide (Dl) values are used to evaluate gas exchange; however, the quality of maneuvers performed by children has not been evaluated, and reference values for young people living at moderate altitudes are not well established.

Objectives: Our objectives were 1) to determine whether Dl maneuvers performed by a pediatric population would meet 2017 European Respiratory Society/American Thoracic Society (ERS/ATS) quality control standards; and 2) to report normal Dl values for Mexican/Latino children and adolescents living at moderate altitudes.

Methods: This study involved healthy young people 4-20 years of age from the metropolitan area of Mexico City (2,240 m above sea level) who were recruited in schools from July 2014 to August 2017.

[Prevalence of sleep symptoms and risk of obstructive sleep apnea in Mexico.].

Objective: To estimate the prevalence of sleep related symptoms (SRS) in Mexico, and their distribution by region, urbanization and gender.

Materials And Methods: Cross-sectional study using a national probabilistic sample among adults over 20 years old. We applied the Berlin questionnaire for sleep apnea risk (OSA) and questions on sleep duration, insomnia and sedative use.

Small airway dysfunction in chronic hypersensitivity pneumonitis.

Background And Objective: Lung biopsies from patients with hypersensitivity pneumonitis (HP) have demonstrated small airway (SA) involvement, but there is no information concerning SA function in HP, and it is unknown whether pharmacological treatment could modify its function. SA function in patients with chronic HP using ultrasonic pneumography (UPG) and impulse oscillometry (IOS) was explored. We also compared initial results with those obtained after 4 weeks of standardized treatment with azathioprine and prednisone.

Variability of FeNO in healthy subjects at 2240 meters above sea level.

Fraction of exhaled nitric oxide (FeNO) is a marker of eosinophilic airway inflammation. Altitude above sea level can affect measurements of this index, but there is only limited information regarding the diurnal variation (ante meridiem vs. post meridiem) and reproducibility of FeNO on consecutive days at moderate altitudes.