Angiotensin II Directly Increases Endothelial Calcium and Nitric Oxide in Kidney and Brain Microvessels In Vivo With Reduced Efficacy in Hypertension.

BACKGROUND: The vasoconstrictor effects of angiotensin II via type 1 angiotensin II receptors in vascular smooth muscle cells are well established, but the direct effects of angiotensin II on vascular endothelial cells (VECs) in vivo and the mechanisms how VECs may mitigate angiotensin II-mediated vasoconstriction are not fully understood. The present study aimed to explore the molecular mechanisms and pathophysiological relevance of the direct actions of angiotensin II on VECs in kidney and brain microvessels in vivo. METHODS AND RESULTS: Changes in VEC intracellular calcium ([Ca2+]i) and nitric oxide (NO) production were visualized by intravital multiphoton microscopy of cadherin 5-Salsa6f mice or the endothelial uptake of NO-sensitive dye 4-amino-5-methylamino-2',7'-difluorofluorescein diacetate, respectively. Kidney fibrosis by unilateral ureteral obstruction and Ready-to-use adeno-associated virus expressing Mouse Renin 1 gene (Ren1-AAV) hypertension were used as disease models. Acute systemic angiotensin II injections triggered >4-fold increases in VEC [Ca2+]i in brain and kidney resistance arterioles and capillaries that were blocked by pretreatment with the type 1 angiotensin II receptor inhibitor losartan, but not by the type 2 angiotensin II receptor inhibitor PD123319. VEC responded to acute angiotensin II by increased NO production as indicated by >1.5-fold increase in 4-amino-5-methylamino-2',7'-difluorofluorescein diacetate fluorescence intensity. In mice with kidney fibrosis or hypertension, the angiotensin II-induced VEC [Ca2+]i and NO responses were significantly reduced, which was associated with more robust vasoconstrictions, VEC shedding, and microthrombi formation. CONCLUSIONS: The present study directly visualized angiotensin II-induced increases in VEC [Ca2+]i and NO production that serve to counterbalance agonist-induced vasoconstriction and maintain residual organ blood flow. These direct and endothelium-specific angiotensin II effects were blunted in disease conditions and linked to endothelial dysfunction and the development of vascular pathologies.

Neuronally differentiated macula densa cells regulate tissue remodeling and regeneration in the kidney.

Tissue regeneration is limited in several organs including the kidney, contributing to the high prevalence of kidney disease globally. However, evolutionary and physiological adaptive responses and the presence of renal progenitor cells suggest existing remodeling capacity. This study uncovered endogenous tissue remodeling mechanisms in the kidney that were activated by the loss of body fluid and salt and regulated by a unique niche of a minority renal cell type called the macula densa (MD). Here we identified neuronal differentiation features of MD cells that sense the local and systemic environment, secrete angiogenic, growth and extracellular matrix remodeling factors, cytokines and chemokines, and control resident progenitor cells. Serial intravital imaging, MD nerve growth factor receptor and Wnt mouse models and transcriptome analysis revealed cellular and molecular mechanisms of these MD functions. Human and therapeutic translation studies illustrated the clinical potential of MD factors including CCN1 as a urinary biomarker and therapeutic target in chronic kidney disease. The concept that a neuronally differentiated key sensory and regulatory cell type responding to organ-specific physiological inputs controls local progenitors to remodel or repair tissues may be applicable to other organs and diverse tissue regenerative therapeutic strategies.

Barriers and facilitators to access sexual and reproductive health services among young migrants in Tarapacá, Chile: a qualitative study.

BACKGROUND: Chile has become a destination country for immigrants from Latin America, including youth. Guaranteeing access and use of sexual and reproductive health services for young migrants is crucial because of their overlapping experiences of transitioning to a new country and to adulthood. However, the existing evidence shows barriers to accessing sexual and reproductive healthcare among young migrant populations. In this context, the main objective of this article is to identify the barriers and facilitators that young migrants experience to access sexual and reproductive healthcare in the Tarapacá region of Chile. METHODS: A qualitative study was conducted in the Tarapacá region of Chile. Semi-structured interviews with 25 young migrants from Venezuela, Colombia, and Ecuador, as well as 10 health workers, were carried out. The interviews were transcribed and thematically analysed. The study was approved by the Ethics Committee of the Universidad del Desarrollo (#2019-22). RESULTS: Young migrants face barriers linked to structural shortcomings within the healthcare system, which may be similar to those faced by the local population. Barriers are also derived from reductionist sexual and reproductive health approaches, which prioritise the prevention of pregnancy, sexually transmitted infections, and HIV, with a predominantly heteronormative focus. The prevailing narratives from the health system are those of risk and lack of control and self-care among young people, and they are exacerbated in the case of migrants. Young migrants, especially from the Caribbean, are stereotyped as over-sexualised and liberal in comparison to the local population and believed to be engaging in riskier sexual behaviours that should be kept under check. This may translate into experiences of discrimination and mistreatment when receiving care. Facilitators include good-quality information and community-level interventions. CONCLUSIONS: This study shows a limited approach to the sexual and reproductive health of young migrants in Chile, severely hampering their reproductive and sexual rights. Policies and initiatives must work towards removing structural barriers, changing narratives, and empowering young migrants regarding their sexual and reproductive health.

Neurodevelopmental assessment of normocephalic children born to Zika virus exposed and unexposed pregnant people.

BACKGROUND: Studies examining the association between in utero Zika virus (ZIKV) exposure and child neurodevelopmental outcomes have produced varied results. METHODS: We aimed to assess neurodevelopmental outcomes among normocephalic children born from pregnant people enrolled in the Zika in Pregnancy in Honduras (ZIPH) cohort study, July-December 2016. Enrollment occurred during the first prenatal visit. Exposure was defined as prenatal ZIKV IgM and/or ZIKV RNA result at enrollment. Normocephalic children, >6 months old, were selected for longitudinal follow-up using the Bayley Scales of Infant and Toddler Development (BSID-III) and the Ages & Stages Questionnaires: Social-Emotional (ASQ:SE-2). RESULTS: One hundred fifty-two children were assessed; after exclusion, 60 were exposed and 72 were unexposed to ZIKV during pregnancy. Twenty children in the exposed group and 21 children in the unexposed group had a composite score <85 in any of the BSID-III domains. Although exposed children had lower cognitive and language scores, differences were not statistically significant. For ASQ:SE-2 assessment, there were not statistically significant differences between groups. CONCLUSIONS: This study found no statistically significant differences in the neurodevelopment of normocephalic children between in utero ZIKV exposed and unexposed. Nevertheless, long-term monitoring of children with in utero ZIKV exposure is warranted. IMPACT: This study found no statistically significant differences in the neurodevelopment in normocephalic children with in utero Zika virus exposure compared to unexposed children, although the exposed group showed lower cognitive and language scores that persisted after adjustment by maternal age and education and after excluding children born preterm and low birth weight from the analysis. Children with prenatal Zika virus exposure, including those normocephalic and have no evidence of abnormalities at birth, should be monitored for neurodevelopmental delays. Follow-up is important to be able to detect developmental abnormalities that might not be detected earlier in life.

Testicular Germ Cell Tumors in Children and Adolescents Treated With Bleomycin, Etoposide, and Cisplatin (BEP) Protocol: A Survival Analysis.

BACKGROUND: Germ cell tumors (GCTs) represent a diverse group of rare neoplasms that vary in location, histology, and clinical presentation. This study focuses on the clinical outcomes and survival rates of children and adolescents treated with the bleomycin, etoposide, and cisplatin (BEP) protocol. METHODS: This observational study evaluated children under 18 years diagnosed with testicular germ cell tumors and treated with the BEP protocol from January 2008 to December 2018. We employed descriptive analysis and used the Kaplan-Meier method to calculate event-free survival (EFS) and overall survival rates. RESULTS: The study included 32 patients with an average age of 9.8 years (SD ± 6.7). The primary reason for consultation was a testicular mass. The classification of patients was E-I for 14 patients (44%) and E-III and E-IV for nine patients (28%). Endodermal sinus tumors and mixed germ cell tumors were the most commonly identified histological types. With a median follow-up of 7.8 years (95% confidence interval {CI}: 5.9-9.6), the event-free survival was 63.7%. The overall survival at a median follow-up of 9.1 years (95% CI: 7.5-10.7) was 76.1%. CONCLUSION: The BEP chemotherapy regimen offers promising results for treating testicular germ cell tumors in children and adolescents, characterized by its low toxicity and minimal late side effects. However, patients older than 11 years displayed more adverse histological indicators, advanced disease stages, and higher relapse and mortality rates.

The role of organic cations as additives in photovoltaic perovskites.

The design of additives for perovskite-based solar cells seeks to improve the balance between stability and power conversion efficiency. Organic molecules such as theophylline, theobromine and caffeine (xanthines) have proved to be a good engineering solution. As an alternative, we present a first-principles study of the use of organic cations as additives. These cations are obtained when the free nitrogen of the imidazole unit of the aforementioned molecules is quaternized. We have found that the interaction between the organic cations and the MAPbI3 perovskite surface is stronger compared to the organic molecules. The Pb-O and I-H bonds of the interface dominated these interactions. In addition, organic cations showed higher charge transfer through the interface and shallow states that are harmless and could improve the charge carrier mobility. These characteristics show that quaternized xanthines should be a promising additive for perovskite materials in photovoltaic applications.

Pediatric Blastic Plasmacytoid Dendritic Cell Neoplasm, Clinical Features and Immunophenotype: A Case Report.

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare but aggressive malignancy with high mortality involving the skin and hematopoietic system. Clinical suspicion is difficult, and management of skin lesions is challenging due to their indolent course prior to dissemination. We describe a patient with isolated skin involvement who progressed to CD4+/CD56+ and CD123+ acute leukemia.

Promoting the Participation of "Hard-to-Reach" Migrant Populations in Qualitative Public Health Research during the COVID-19 Pandemic in Chile.

The COVID-19 pandemic has further deepened socioeconomic and health inequities worldwide, especially among populations experiencing social vulnerability, such as international migrants. Sustained lockdowns and social distancing have raised challenges to conducting public health research with hard-to-reach populations. This study aims at exploring strategies to recruit "hard-to-reach" international migrants for qualitative public health research during the pandemic in Chile, based on the authors' experience. A retrospective qualitative evaluation process was carried out on the recruitment processes of three qualitative research projects focused on international migrants in Chile. All projects were implemented during the COVID-19 pandemic, demanding complementary and flexible strategies: (i) social media; (ii) snowball sampling; (iii) referrals from social workers and pro-migrant and migrant-led organizations; (iv) vaccination centers and healthcare centers; and (v) community-based recruitment. The strategies are qualitatively evaluated around seven emerging qualitative categories: (i) feasibility during lockdown periods; (ii) speed of recruitment; (iii) geographical coverage; (iv) sample diversity; (v) proportion of successful interviews; (vi) ethical considerations; and (vii) cost. Engaging hard-to-reach international migrants in public health research during the pandemic required constantly adapting recruitment strategies. Furthermore, relying on strategies that were not only Internet-based promoted the participation of populations with limited access to the Internet and low-digital literacy.

Epilepsia y quemados: Descripción de casos

La epilepsia es uno de los trastornos neurológicos más frecuentes a nivel mundial y afecta a más de 70 millones de personas en todo el mundo, las quemaduras son eventos traumáticos que representan un importante problema de salud pública. Método: Se realizó un estudio descriptivo de corte transversal, se incluyeron pacientes con quemaduras secundarias a eventos convulsivos, en un hospital de Bogotá, Colombia entre agosto de 2019 y diciembre de 2020, con el objetivo de describir la frecuencia y características de las quemaduras secundarias a un evento convulsivo en esta población. Resultados: La mayoría de los casos se presentó en mujeres solteras (65%) con una edad promedio de 44 años provenientes en su mayoría de zona urbana (70%), con ocupación principal ama de casa (45%), el principal desencadenante de la crisis epiléptica fue la mala adherencia al tratamiento (70%), el 95% de los pacientes no tuvo un control previo por neurología y el área corporal más afectada fue las extremidades superiores (brazos) en el 55%, la estancia hospitalaria promedio fue de 20 días en Unidad de Cuidados Intensivos. Conclusión: La epilepsia es una enfermedad prevalente, una baja adherencia a la medicación y un inadecuado seguimiento neurológico pueden llevar a problemas graves como las quemaduras, con la consecuente afectación de la calidad de vida de los pacientes y estancias en UCI prolongadas, así como secuelas importantes que imposibiliten la reincorporación laboral de la persona, convirtiéndose en un problema de salud pública.

Epilepsy is one of the most common neurological disorders worldwide, affecting more than 70 million people worldwide; on the other hand, burns are traumatic events that represent an important public health problem. Considering the relationship that has been documented between epilepsy and burns, a descriptive cross-sectional study was carried out in the burn unit of a tertiary care hospital in the city of Bogotá, Colombia. 78 medical records were reviewed, 20 correspond to patients burned during a convulsive episode, most of the cases occurred in single women (65%) with an average age of 44 years, mostly from urban areas (70%), with main occupation housewife (45%), the main trigger of the epileptic crisis was poor adherence to treatment (70%), 95% of the patients did not have a previous control by neurology and the body area most affected was the upper limbs (arms) in 55%, the average hospital stay was 20 days in the Intensive Care Unit. Epilepsy is a disease with poor adherence to medication and inadequate neurological follow-up that may be related to the presence of convulsive episodes, which can lead to serious problems such as burns, with the consequent impact on the quality of life of patients. as well as important consequences that make it impossible for the person to return to work, becoming a public health problem.

Delta Storage Pool Deficiency: A Pediatric Case Report and Review of the Literature.

Platelet storage deficiencies are a heterogeneous group of bleeding disorders of variable severity caused by decreased number or content of platelet granules. We present the case of a 10-year-old patient with no personal history of previous bleeding who was admitted to the emergency department due to menorrhagia and mucocutaneous pallor. Common disorders of primary and secondary hemostasis were ruled out. Subsequently, a study of electron microscopy of platelets was performed, which reported the presence of alpha granules with a decreased number of dense granules. Currently, the patient receives treatment with tranexamic acid during menstrual periods, supplementation with ferrous sulfate, and oral contraceptives, achieving control of bleeding episodes.

Perceptions of Health Needs among Venezuelan Women Crossing the Border in Northern Chile during the COVID-19 Pandemic.

In parallel to the COVID-19 pandemic, Chile has experienced a significant influx of international migrants, many of whom are Venezuelan women who have entered the country through unauthorized crossing points. In this context, gender and migration intersect as the social determinants of health, leading to their experiencing a range of adverse events. This poses important challenges in terms of short- and long-term health outcomes, the social determinants of health, and access to healthcare. This study aims at describing Venezuelan women's perceptions of their health needs as they migrate to Chile via an unauthorized crossing point, with a focus on adverse events throughout the migration cycle, self-reported health needs, and responses. A qualitative case study was carried out with 22 participants in the Antofagasta region of Chile, including Venezuelan migrant women, healthcare professionals, and social workers from the public healthcare system, stakeholders from non-governmental and international organizations, and local government officials. The semi-structured, individual interviews were analyzed thematically. The results show that Venezuelan women face a range of adverse events throughout the migration cycle. The perceived health needs that are reported are sometimes linked to these adverse events or existed prior to migration and were exacerbated throughout the migratory cycle. Addressing these physical and mental health needs is essential for short- and long-term individual and public health; however, despite substantial efforts to ameliorate the situation, persisting gaps in access to care are reported.

Aceptabilidad de la vacuna contra la COVID-19 en alumnos de una universidad pública de Honduras / Acceptability of the COVID-19 vaccine in students of a public university in Honduras

La pandemia de la COVID-19 continúa reportando casos y fallecimientos a nivel mundial y nacional. La vacuna contra COVID-19, ha logrado contener la propagación de la enfermedad, sin embargo, todavía no tiene una aceptación total. Objetivo: Determinar el nivel de conocimiento, actitudes y aceptabilidad de la vacuna contra la COVID-19 y factores asociados, en estudiantes de la Universidad Nacional Autónoma de Honduras (UNAH) en año 2021. Métodos: Estudio observacional, transversal, descriptivo con análisis de asociación. La población de estudio fueron los estudiantes de la UNAH. Resultados: Un total de 1,417 estudiantes participaron, de los cuales el 52.3% (741) no estaban vacunados contra la COVID-19. Se encontró que el 93.5% (693/741) aceptaría aplicarse la vacuna. Se realizó una regresión logística binaria múltiple reportando que, el grupo de edad de 40 a 44 años tendrían mayor posibilidad de no aceptabilidad de la vacuna (OR=17, IC95% 2.462-120.661; p=0.004). Con respecto a los factores psicosociales se encontró que, la norma subjetiva y el control conductual inadecuado conllevaría a mayor posibilidad de no aceptación de la vacuna. (OR=11.4, IC95% 3.605- 36.664; p=0.000) y (OR=4.6, IC95% 1.678-12.281; p=0.003), respectivamente. Finalmente, la actitud social y la percepción de riesgo inadecuado implicaría no aceptar la vacuna (OR=13, IC95% 5.683-30.322; p=0.000) y (OR=6, IC95% 2.189- 15.159; p=0.000), respectivamente. Discusión: Según los resultados de este estudio, los estudiantes que no aceptaron vacunarse tuvieron influencia en su entorno familiar, social y de su propia capacidad para decidir, sumado a una percepción de riesgo inadecuada por una influencia directa en los mismos...(AU)

Manufacturing of Complex Silicon-Carbon Structures: Exploring SixCy Materials.

This paper reports on the manufacturing of complex three-dimensional Si/C structures via a chemical vapor deposition method. The structure and properties of the grown materials were characterized using various techniques including scanning electron microscopy, aberration-corrected transmission electron microscopy, confocal Raman spectroscopy, and X-ray photoelectron spectroscopy. The spectroscopy results revealed that the grown materials were composed of micro/nanostructures with various compositions and dimensions. These included two-dimensional silicon carbide (SiC), cubic silicon, and various SiC polytypes. The coexistence of these phases at the nano-level and their interfaces can benefit several Si/C-based applications ranging from ceramics and structural applications to power electronics, aerospace, and high-temperature applications. With an average density of 7 mg/cm3, the grown materials can be considered ultralightweight, as they are three orders of magnitude lighter than bulk Si/C materials. This study aims to impact how ceramic materials are manufactured, which may lead to the design of new carbide materials or Si/C-based lightweight structures with additional functionalities and desired properties.

Angiosarcoma cutáneo en una adolescente con Xeroderma Pigmentoso: Reporte de caso / Cutaneous angiosarcoma in an adolescent girl with Xeroderma Pigmentosum: A case report

Resumen El Xeroderma Pigmentoso (XP) es un trastorno poco frecuente, autosómico recesivo y caracterizado por una extrema sensibilidad a la radiación ultravioleta (RUV) de la luz solar, que produce una reparación defectuosa del daño del ADN y como consecuencia, marcada predisposición al desarrollo de cáncer de piel. Clínicamente, se manifiesta por fotosensibilidad, cambios cutáneos pigmentarios y envejecimiento prematuro de la piel. Este trastorno afecta aproximadamente 1 de cada 250.000 habitantes por año en Estados Unidos. Presentamos el caso de una paciente de 12 años con un Xeroderma Pigmentoso detectado a los 6 meses, quien desarrolló una lesión ulcerada en la vertiente nasal izquierda con reporte de patología de Angiosarcoma (AS) con CD31, EGR y CD34 positivos. La paciente fue tratada con resección amplia de la lesión y quimioterapia adyuvante con Plaquitaxel y Doxorrubicina sin radioterapia.

Abstract Xeroderma Pigmentosum is a rare autosomal recessive disorder characterized by extreme sensitivity to ultraviolet radiation (UVR) from sunlight that results in a defective repair of DNA damage and, as a consequence, a marked predisposition to the development of cancer of the skin. Its clinical manifestations are photosensitivity, pigmentary skin changes, and premature aging of the skin. This disorder affects approximately 1 in 250,000 individuals per year in the United States. We present the case of a 12-year-old patient with Xeroderma Pigmentosum detected at 6 months of age, who developed an ulcerated lesion on the left nasal slope with a pathology report of angiosarcoma (AS), which we positive for ERG, CD31, and CD34. The patient was treated with wide resection of the lesion and adjuvant chemotherapy with paclitaxel and doxorubicin without radiation therapy.

Visualizing Grain Statistics in MOCVD WSe2 through Four-Dimensional Scanning Transmission Electron Microscopy.

Using four-dimensional scanning transmission electron microscopy, we demonstrate a method to visualize grains and grain boundaries in WSe2 grown by metal organic chemical vapor deposition (MOCVD) directly onto silicon dioxide. Despite the chemical purity and uniform thickness and texture of the MOCVD-grown WSe2, we observe a high density of small grains that corresponds with the overall selenium deficiency we measure through ion beam analysis. Moreover, reconstruction of grain information permits the creation of orientation maps that demonstrate the nucleation mechanism for new layers-triangular domains with the same orientation as the layer underneath induces a tensile strain increasing the lattice parameter at these sites.

Intrinsic helical twist and chirality in ultrathin tellurium nanowires.

Robust atomic-to-meso-scale chirality is now observed in the one-dimensional form of tellurium. This enables a large and counter-intuitive circular-polarization dependent second harmonic generation response above 0.2 which is not present in two-dimensional tellurium. Orientation variations in 1D tellurium nanowires obtained by four-dimensional scanning transmission electron microscopy (4D-STEM) and their correlation with unconventional non-linear optical properties by second harmonic generation circular dichroism (SHG-CD) uncovers an unexpected circular-polarization dependent SHG response from 1D nanowire bundles - an order-of-magnitude higher than in single-crystal two-dimensional tellurium structures - suggesting the atomic- and meso-scale crystalline structure of the 1D material possesses an inherent chirality not present in its 2D form; and which is strong enough to manifest even in the aggregate non-linear optical (NLO) properties of aggregates.

Microcephaly Outcomes among Zika Virus-Infected Pregnant Women in Honduras.

The impact of Zika virus (ZIKV) infection on pregnancies shows regional variation emphasizing the importance of studies in different geographical areas. We conducted a prospective study in Tegucigalpa, Honduras, recruiting 668 pregnant women between July 20, 2016, and December 31, 2016. We performed Trioplex real-time reverse transcriptase-PCR (rRT-PCR) in 357 serum samples taken at the first prenatal visit. The presence of ZIKV was confirmed in seven pregnancies (7/357, 2.0%). Nine babies (1.6%) had microcephaly (head circumference more than two SDs below the mean), including two (0.3%) with severe microcephaly (head circumference [HC] more than three SDs below the mean). The mothers of both babies with severe microcephaly had evidence of ZIKV infection. A positive ZIKV Trioplex rRT-PCR was associated with a 33.3% (95% CI: 4.3-77.7%) risk of HC more than three SDs below the mean.

Alveolar Soft Part Sarcoma of the Tongue in an Adolescent.

Alveolar soft part sarcoma is a rare malignant soft tissue neoplasm of uncertain histogenesis and aggressive clinical behavior. Alveolar soft part sarcoma arises in the head and neck in 27% of cases, with 25% of head and neck cases occurring in the tongue. Herein the case of a pediatric patient diagnosed with alveolar soft tissue sarcoma of the tongue, who received surgical treatment with total resection of the lesion and chemotherapy without radiotherapy, is presented. To date, the patient is in remission of the disease.

1D to 2D Transition in Tellurium Observed by 4D Electron Microscopy.

A new microwave-enhanced synthesis method for the production of tellurium nanostructures is reported-with control over products from the 1D regime (sub-5 nm diameter nanowires), to nanoribbons, to the 2D tellurene regime-along with a new methodology for local statistical quantification of the crystallographic parameters of these materials at the nanometer scale. Using a direct electron detector and image-corrected microscope, large and robust 4D scanning transmission electron microscopy datasets for accurate structural analysis are obtained. These datasets allow the adaptation of quantitative techniques originally developed for X-ray diffraction (XRD) refinement analyses to transmission electron microscopy, enabling the first demonstration of sub-picometer accuracy lattice parameter extraction while also obtaining both the size of the coherent crystallite domains and the nanostrain, which is observed to decrease as nanowires transition to tellurene. This new local analysis is commensurate with global powder XRD results, indicating the robustness of both the new synthesis approach and new structural analysis methodology for future scalable production of 2D tellurene and characterization of nanomaterials.

Clinical Course of Pediatric Acute Respiratory Distress Syndrome at Moderate Altitude.

Background This is a retrospective case series, and the main objective is to describe the epidemiology, clinical features, and outcomes of pediatric acute respiratory distress syndrome in patients at moderate altitude. Methods Children from the Pediatric Intensive Care Unit (PICU) at the Fundación Cardioinfantil, hospitalized with acute respiratory distress syndrome, were prospectively enrolled from March 2009 to March 2014. We evaluated the demographic data, mechanical ventilation, gas exchange, hemodynamics, and multiorgan dysfunction. Results During the study period, 88 patients met the inclusion criteria. Bronchiolitis and pneumonia were the most common causes of acute respiratory distress syndrome. The overall mortality rate was 19.5%. At the beginning of the study, the average relation between blood pressure and the fraction of inspired oxygen (Pa/Fi) was 130.3 ± 52.2; tidal volume was 7.94 ± 1.7 ml/kg, the plateau pressure 25.3 ± 5.09 cmH2O, and positive end-expiratory pressure was 7.2 ± 3.2 cmH2O. After 24 hours, the mortality rate in the group with severe acute respiratory distress syndrome (Pa/Fi <100) was 46.7%, in the moderate acute respiratory distress syndrome group (Pa/Fi 100-200) it was 11.9%, and finally in the mild acute respiratory distress syndrome group (Pa/Fi 200-300) the mortality was 25%. This study found a relation between serum lactate value and positive end-expiratory pressure and mortality (p = 0.02 and 0.0013). Conclusions This study shows that pediatric acute respiratory distress syndrome patients at moderate altitudes have similar clinical behavior, including mortality rate, to those at low altitudes. However, Pa/Fi is not a good predictor of mortality for patients with mild and moderate acute respiratory distress syndrome.