Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 39
Filtrar
1.
Suicide Life Threat Behav ; 54(2): 338-348, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38265111

RESUMEN

INTRODUCTION: Borderline personality disorder (BPD) is a disorder of pervasive emotion dysregulation associated with high rates of self-injurious thoughts and behaviors (SITB). Understanding specific emotion states in relation to SITB is important for effective intervention. METHODS: The current study examined whether, and how, the specific emotion of shame contributes to suicide ideation and urges to engage in non-suicidal self-injury (NSSI) both directly, and indirectly via anger, among individuals with BPD. Participants (N = 100) were enrolled in a 6-month comprehensive dialectical behavior therapy (DBT) program and provided daily ratings of shame, anger, suicide ideation, and urges for NSSI. RESULTS: We found that higher daily ratings of shame and anger were directly associated with higher same-day ratings of both suicidal ideation and urges for NSSI. Furthermore, anger partially mediated the relationships between shame and both suicidal ideation and urges for NSSI. CONCLUSION: These findings highlight shame and anger as potential antecedents of SITB among individuals with BPD. Clinical approaches, such as DBT, that include personalized, ongoing, clinical assessment of these specific affective states may be particularly important for treatment of SITB.


Asunto(s)
Trastorno de Personalidad Limítrofe , Terapia Conductual Dialéctica , Conducta Autodestructiva , Humanos , Ideación Suicida , Trastorno de Personalidad Limítrofe/terapia , Trastorno de Personalidad Limítrofe/psicología , Resultado del Tratamiento , Conducta Autodestructiva/terapia , Conducta Autodestructiva/psicología , Ira , Vergüenza , Terapia Conductista
2.
Am J Hematol ; 99(1): 88-98, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-38032792

RESUMEN

Blood volume (BV) is an important clinical parameter and is usually reported per kg of body mass (BM). When fat mass is elevated, this underestimates BV/BM. One aim was to study if differences in BV/BM related to sex, age, and fitness would decrease if normalized to lean body mass (LBM). The analysis included 263 women and 319 men (age: 10-93 years, body mass index: 14-41 kg/m2 ) and 107 athletes who underwent assessment of BV and hemoglobin mass (Hbmass ), body composition, and cardiorespiratory fitness. BV/BM was 25% lower (70.3 ± 11.3 and 80.3 ± 10.8 mL/kgBM ) in women than men, respectively, whereas BV/LBM was 6% higher in women (110.9 ± 12.5 and 105.3 ± 11.2 mL/kgLBM ). Hbmass /BM was 34% lower (8.9 ± 1.4 and 11.5 ± 11.2 g/kgBM ) in women than in men, respectively, but only 6% lower (14.0 ± 1.5 and 14.9 ± 1.5 g/kgLBM )/LBM. Age did not affect BV. Athlete's BV/BM was 17.2% higher than non-athletes, but decreased to only 2.5% when normalized to LBM. Of the variables analyzed, LBM was the strongest predictor for BV (R2 = .72, p < .001) and Hbmass (R2 = .81, p < .001). These data may only be valid for BV/Hbmass when assessed by CO re-breathing. Hbmass /LBM could be considered a valuable clinical matrix in medical care aiming to normalize blood homeostasis.


Asunto(s)
Ejercicio Físico , Hemoglobinas , Masculino , Humanos , Femenino , Niño , Adolescente , Adulto Joven , Adulto , Persona de Mediana Edad , Anciano , Anciano de 80 o más Años , Valores de Referencia , Índice de Masa Corporal , Hemoglobinas/análisis , Volumen Sanguíneo
3.
Biomolecules ; 13(8)2023 08 18.
Artículo en Inglés | MEDLINE | ID: mdl-37627327

RESUMEN

Red cell diseases encompass a group of inherited or acquired erythrocyte disorders that affect the structure, function, or production of red blood cells (RBCs). These disorders can lead to various clinical manifestations, including anemia, hemolysis, inflammation, and impaired oxygen-carrying capacity. Oxidative stress, characterized by an imbalance between the production of reactive oxygen species (ROS) and the antioxidant defense mechanisms, plays a significant role in the pathophysiology of red cell diseases. In this review, we discuss the most relevant oxidant species involved in RBC damage, the enzymatic and low molecular weight antioxidant systems that protect RBCs against oxidative injury, and finally, the role of oxidative stress in different red cell diseases, including sickle cell disease, glucose 6-phosphate dehydrogenase deficiency, and pyruvate kinase deficiency, highlighting the underlying mechanisms leading to pathological RBC phenotypes.


Asunto(s)
Anemia Hemolítica Congénita no Esferocítica , Anemia de Células Falciformes , Humanos , Antioxidantes , Eritrocitos , Estrés Oxidativo
4.
Rev Argent Microbiol ; 55(4): 317-331, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37400312

RESUMEN

Bacillus thuringiensis is an entomopathogen belonging to the Bacillus cereus clade. We isolated a tetracycline-resistant strain called m401, recovered it from honey, and identified it as Bacillus thuringiensis sv. kumamotoensis based on the average nucleotide identity calculations (ANIb) comparison and the analysis of the gyrB gene sequences of different B. thuringiensis serovars. Sequences with homology to virulence factors [cytK, nheA, nheB, nheC, hblA, hblB, hblC, hblD, entFM, and inhA] and tetracycline resistance genes [tet(45), tet(V), and tet(M)/tet(W)/tet(O)/tet(S) family] were identified in the bacterial chromosome. The prediction of plasmid-coding regions revealed homolog sequences to the MarR and TetR/AcrR family of transcriptional regulators, toxins, and lantipeptides. The genome mining analysis revealed 12 regions of biosynthetic gene clusters responsible for synthesizing secondary metabolites. We identified biosynthetic gene clusters coding for bacteriocins, siderophores, ribosomally synthesized post-translationally modified peptide products, and non-ribosomal peptide synthetase clusters that provide evidence for the possible use of Bt m401 as a biocontrol agent. Furthermore, Bt m401 showed high inhibition against all Paenibacillus larvae genotypes tested in vitro. In conclusion, Bt m401 owns various genes involved in different biological processes, such as transductional regulators associated with antibiotic resistance, toxins, and antimicrobial peptides with potential biotechnological and biocontrol applications.


Asunto(s)
Bacillus thuringiensis , Bacillus thuringiensis/genética , Microbiología de Alimentos , Filogenia , Bacillus cereus , Antibacterianos/farmacología , Tetraciclina/metabolismo
5.
Curr Microbiol ; 80(4): 120, 2023 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-36856863

RESUMEN

In this study, the effect of native plant-growth-promoting microorganisms (PGPM) as bio-inoculants was assessed as an alternative to improve Ilex paraguariensis Saint Hilaire growth in the nursery. Fourteen Trichoderma strains isolated from yerba mate roots were evaluated in vitro for their potential as biological control agents (BCA) and PGPM. The PGPM properties were evaluated through the strain's antagonistic activity against three fungal pathogens (Alternaria sp., F. oxysporum, and F. solani) plus the production of extracellular cell-wall-degrading enzymes such as chitinase, ß-1,3-glucanase, and cellulase. These results were used to calculate different PGPM indices to select the strains with the optimal properties. Four Trichoderma strains: T. asperelloides LBM193, LBM204, LBM206, and Trichoderma sp. LBM202, were selected based on their indirect and direct PGPM properties used in an inoculation assay on yerba mate plants in greenhouse conditions. A highly significant positive effect of bio-inoculation with these Trichoderma strains was observed in one-year-old yerba mate seedlings. Inoculated plants exhibited a greater height, chlorophyll content, and dry weight than un-inoculated plants; those treated with LBM193 manifested the best results. Yerba mate plants treated with LBM202 exhibited a healthy appearance and were more vigorous, showing potential for biocontrol agent. In conclusion, yerba mate seedlings in the Misiones region were found to have a reservoir of Trichoderma species that increases the yield of this crop in the nursery and protects them from adverse biotic and abiotic agents.


Asunto(s)
Ilex paraguariensis , Trichoderma , Agentes de Control Biológico , Alternaria , Bioensayo , Plantones
6.
J Community Psychol ; 51(8): 3152-3170, 2023 11.
Artículo en Inglés | MEDLINE | ID: mdl-36950766

RESUMEN

Burgeoning research has documented COVID-19's detrimental impacts globally, especially on the lives of adolescents. The present study examined the positive influences of a virtual, cross-age peer mentoring program on the development of adolescent participants in the face of the hardships created by the pandemic. In particular, this study focuses on the experiences of high school participants who served as both mentors and mentees in the program. Semi-structured interviews with participating high schoolers (n = 13) were coded and analyzed using the thematic analysis process. The interview data indicated that increased social support, the agency in prosocial pursuits, and greater purpose engagement resulted from their participation in the program. Results are discussed in the context of self-determination theory: youths' needs for relatedness, competence, and autonomy. The program met these basic needs among participants which in turn supported purpose exploration during the pandemic.


Asunto(s)
COVID-19 , Tutoría , Adolescente , Humanos , Mentores , Tutoría/métodos , Grupo Paritario , Instituciones Académicas
7.
Artículo en Inglés | MEDLINE | ID: mdl-36834096

RESUMEN

Previous studies have suggested that social and cultural factors significantly influence people's willingness to use the male contraceptive pill, which is in relatively advanced development. The present study aims at comparing Spanish and Mozambican participants level of willingness to take a male contraceptive pill. Factorial designed scenarios were used to collect data on the two population samples (Spain = 402 participants; Mozambique = 412 participants). One-way analysis of variance (ANOVAs) were performed comparing the average scores of Mozambique and Spain at the levels of each modelled factor: The cost of the pills (30 €/USD 20 for 3 months vs. free); Efficacy (99% vs. 95%); Side effects (none, mild and severe); Context (disease, condom abandonment and diversification of contraceptive methods). The two groups found significant differences in the scores for each of the four factors, in light of the socio-cultural differences between the two countries. In the Spanish sample, the main factor affected the willingness to use male contraceptive pill (MCP) were the side effects, while for Mozambican men it was the context. Along with technological change, an ideological-social change in gender roles is required to ensure equity in contraceptive responsibilities and the participation of men at all socio-demographic levels in reproductive health.


Asunto(s)
Anticonceptivos Masculinos , Masculino , Humanos , Mozambique , España , Anticonceptivos , Anticoncepción
8.
ACS Omega ; 8(1): 147-168, 2023 Jan 10.
Artículo en Inglés | MEDLINE | ID: mdl-36643550

RESUMEN

Red blood cells (RBCs) are exposed to both external and internal sources of oxidants that challenge their integrity and compromise their physiological function and supply of oxygen to tissues. Autoxidation of oxyhemoglobin is the main source of endogenous RBC oxidant production, yielding superoxide radical and then hydrogen peroxide. In addition, potent oxidants from other blood cells and the surrounding endothelium can reach the RBCs. Abundant and efficient enzymatic systems and low molecular weight antioxidants prevent most of the damage to the RBCs and also position the RBCs as a sink of vascular oxidants that allow the body to maintain a healthy circulatory system. Among the antioxidant enzymes, the thiol-dependent peroxidase peroxiredoxin 2, highly abundant in RBCs, is essential to keep the redox balance. A great part of the RBC antioxidant activity is supported by an active glucose metabolism that provides reducing power in the form of NADPH via the pentose phosphate pathway. There are several RBC defects and situations that generate oxidative stress conditions where the defense mechanisms are overwhelmed, and these include glucose-6-phosphate dehydrogenase deficiencies (favism), hemoglobinopathies like sickle cell disease and thalassemia, as well as packed RBCs for transfusion that suffer from storage lesions. These oxidative stress-associated pathologies of the RBCs underline the relevance of redox balance in these anucleated cells that lack a mechanism of DNA-inducible antioxidant response and rely on a complex and robust network of antioxidant systems.

9.
Am J Clin Nutr ; 115(4): 1166-1179, 2022 04 01.
Artículo en Inglés | MEDLINE | ID: mdl-34910118

RESUMEN

BACKGROUND: Inflammation during pregnancy may aggravate iron deficiency (ID) by increasing serum hepcidin and reducing iron absorption. This could restrict iron transfer to the fetus, increasing risk of infant ID and its adverse effects. OBJECTIVES: We aimed to assess whether iron bioavailability and/or iron transfer to the fetus is impaired in overweight/obese (OW) pregnant women with adiposity-related inflammation, compared with normal-weight (NW) pregnant women. METHODS: In this prospective study, we followed NW (n = 43) and OW (n = 40) pregnant women who were receiving iron supplements from the 14th week of gestation to term and followed their infants to age 6 mo. We administered 57Fe and 58Fe in test meals mid-second and mid-third trimester, and measured tracer kinetics throughout pregnancy and infancy. RESULTS: In total, 38 NW and 36 OW women completed the study to pregnancy week 36, whereas 30 NW and 27 OW mother-infant pairs completed the study to 6 mo postpartum. Both groups had comparable iron status, hemoglobin, and serum hepcidin throughout pregnancy. Compared with the NW, the OW pregnant women had 1) 43% lower fractional iron absorption (FIA) in the third trimester (P = 0.033) with median [IQR] FIA of 23.9% [11.4%-35.7%] and 13.5% [10.8%-19.5%], respectively; and 2) 17% lower maternal-fetal iron transfer from the first tracer (P = 0.051) with median [IQR] maternal-fetal iron transfer of 4.8% [4.2%-5.4%] and 4.0% [3.6%-4.6%], respectively. Compared with the infants born to NW women, infants born to OW women had lower body iron stores (BIS) with median [IQR] 7.7 [6.3-8.8] and 6.6 [4.6-9.2] mg/kg body weight at age 6 mo, respectively (P = 0.024). Prepregnancy BMI was a negative predictor of maternal-fetal iron transfer (ß = -0.339, SE = 0.144, P = 0.025) and infant BIS (ß = -0.237, SE = 0.026, P = 0.001). CONCLUSIONS: Compared with NW, OW pregnant women failed to upregulate iron absorption in late pregnancy, transferred less iron to their fetus, and their infants had lower BIS. These impairments were associated with inflammation independently of serum hepcidin.This trial was registered at clinicaltrials.gov as NCT02747316.


Asunto(s)
Hierro , Sobrepeso , Niño , Femenino , Feto , Humanos , Lactante , Cinética , Embarazo , Estudios Prospectivos
10.
J Biol Chem ; 298(1): 101503, 2022 01.
Artículo en Inglés | MEDLINE | ID: mdl-34929164

RESUMEN

Hydrogen peroxide (H2O2) not only is an oxidant but also is an important signaling molecule in vascular biology, mediating several physiological functions. Red blood cells (RBCs) have been proposed to be the primary sink of H2O2 in the vasculature because they are the main cellular component of blood with a robust antioxidant defense and a high membrane permeability. However, the exact permeability of human RBC to H2O2 is neither known nor is it known if the mechanism of permeation involves the lipid fraction or protein channels. To gain insight into the permeability process, we measured the partition constant of H2O2 between water and octanol or hexadecane using a novel double-partition method. Our results indicated that there is a large thermodynamic barrier to H2O2 permeation. The permeability coefficient of H2O2 through phospholipid membranes containing cholesterol with saturated or unsaturated acyl chains was determined to be 4 × 10-4 and 5 × 10-3 cm s-1, respectively, at 37 °C. The permeability coefficient of human RBC membranes to H2O2 at 37 °C, on the other hand, was 1.6 × 10-3 cm s-1. Different aquaporin-1 and aquaporin-3 inhibitors proved to have no effect on the permeation of H2O2. Moreover, human RBCs devoid of either aquaporin-1 or aquaporin-3 were equally permeable to H2O2 as normal human RBCs. Therefore, these results indicate that H2O2 does not diffuse into RBCs through aquaporins but rather through the lipid fraction or a still unidentified membrane protein.


Asunto(s)
Acuaporinas , Membrana Eritrocítica , Eritrocitos , Peróxido de Hidrógeno , Acuaporinas/metabolismo , Permeabilidad de la Membrana Celular , Membrana Eritrocítica/metabolismo , Eritrocitos/metabolismo , Humanos , Peróxido de Hidrógeno/sangre , Peróxido de Hidrógeno/farmacocinética , Metabolismo de los Lípidos
11.
Front Psychol ; 12: 648069, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34093332

RESUMEN

Background: Coronavirus disease 2019 (COVID-19) has resulted in an increase in known risk factors for mental health problems. Mexico adopted lockdown and physical distancing as a containment strategy with potential consequences on day to day life, such as social isolation, loss of income and loneliness that can have important consequences in terms of mental health. Objective: We aimed to examine the effect of the initial phases of the COVID-19 pandemic on psychological distress, well-being and perceived physical health among Mexican-base respondents and to examine whether coping strategies would play a potential intermediating role in relation to these variables. Under the Existential Positive Psychology perspective, an emphasis was made on meaning-centered coping. Methods: A cross-sectional study was conducted between April 30 and June 16th 2020 among 604 Mexicans-base respondents of which 471 were women and 132 men. Data was collected by using online questionnaires. Psychological distress was measured using the Depression, Anxiety, and Stress Scale (DASS-21). The Brief COPE Inventory was used to assess problem-focused and emotion-focused coping strategies. We also used the Meaning-Centered Coping Scale (MCCS). PERMA-Profiler was used to assess well-being, perceived physical health, and loneliness. Profiler and Descriptive analyses and bivariate linear regression were performed to examine the association of variables. Results: 45.9% of the participants reported moderate to extremely severe psychological distress. Our results demonstrate that problem-focused and emotion-focused coping were positively related to psychological distress, whereas meaning-centered coping was negatively associated with distress. Furthermore, psychological distress played a potential negative role in the perceived physical health, while meaning-centered coping and well-being buffered the negative influence of psychological distress on perceived physical health (completely standardized indirect effect = -0.01, SE: 0.012, 95% CI [-0.065; -0.017]. Conclusion: Meaning-centered coping was found to suppress the negative influence of psychological distress on sensation of decreased physical health corroborating the critical role of meaning in life in promoting well-being. Future studies can further examine the value of the critical role of meaning in life in promoting well-being as a protective factor against severe distress during traumatic events. Findings of this study can be used to orient policies and interventions aimed to alleviate suffering in the midst of the COVID-19 pandemic.

12.
Int J Food Microbiol ; 334: 108816, 2020 Dec 02.
Artículo en Inglés | MEDLINE | ID: mdl-32835996

RESUMEN

Bee-pollen is a functional food sold for human and animal consumption but also is a favorable microhabitat for many spore-forming bacteria. Among them, Bacillus cereus can produce several toxins and other virulence factors, causing an emetic or diarrheal syndrome after ingestion. The study involved 36 bee-pollen samples obtained from different sampling points throughout the production process (collecting, freezing, drying, and cleaning) in Argentina. Fifty isolates of B. cereus yielded 24 different fingerprint patterns with BOX and ERIC primers. Only three fingerprint patterns were maintained throughout the production process. In contrast, others were lost or incorporated during the different steps, suggesting that cross-contamination occurred as shown by differences in fingerprint patterns after freezing, drying, and cleaning steps compared to the initial collection step. Genes encoding for cereulide (ces), cytotoxin K (cytK), sphingomyelinase (sph), the components of hemolysin BL (hblA, hblB, hblC, hblD) and non-hemolytic complex (nheAB) were studied. All the isolates displayed one or more enterotoxin genes. The most frequent virulence genes detected belong to the HBL complex, being the most abundant hblA (98%), followed by hblD (64%), hblB (54%), and hblC (32%), respectively. Ten strains (20%), present at all sampling points, carried all the subunits of the HBL complex. The non-hemolytic enterotoxic complex (nheAB) was found in 48 strains (96%), while seven strains (14%) present at all sampling points showed the amplification product for sphingomyelinase (sph). One cereulide-producer was isolated at the cleaning step; this strain contained all the components for the hemolytic enterotoxin complex HBL, the NHE complex, and cytotoxin K related to the foodborne diarrhoeal syndrome. In total, 11 different virulence patterns were observed, and also a correlation between rep-fingerprint and virulence patterns. The results suggest that bee-pollen can be contaminated at any point in the production process with potential enterotoxic B. cereus strains, emphasizing the importance of hygienic processing.


Asunto(s)
Bacillus cereus/patogenicidad , Abejas , Enterotoxinas/genética , Microbiología de Alimentos , Polen , Animales , Argentina , Bacillus cereus/genética , Bacillus cereus/aislamiento & purificación , Enterotoxinas/metabolismo , Manipulación de Alimentos , Polen/microbiología , Polen/toxicidad , Virulencia/genética , Factores de Virulencia/genética , Factores de Virulencia/metabolismo
13.
14.
Mem Inst Oswaldo Cruz ; 115: e190405, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32187327

RESUMEN

BACKGROUND: High-risk human papillomaviruses (HR-HPVs) are the etiological agents of cervical cancer. Among them, types 16 and 18 are the most prevalent worldwide. The HPV genome encodes three oncoproteins (E5, E6, and E7) that possess a high transformation potential in culture cells when transduced simultaneously. In the present study, we analysed how these oncoproteins cooperate to boost key cancer cell features such as uncontrolled cell proliferation, invasion potential, and cellular redox state imbalance. Oxidative stress is known to contribute to the carcinogenic process, as reactive oxygen species (ROS) constitute a potentially harmful by-product of many cellular reactions, and an efficient clearance mechanism is therefore required. Cells infected with HR-HPVs can adapt to oxidative stress conditions by upregulating the formation of endogenous antioxidants such as catalase, glutathione (GSH), and peroxiredoxin (PRX). OBJECTIVES: The primary aim of this work was to study how these oncoproteins cooperate to promote the development of certain cancer cell features such as uncontrolled cell proliferation, invasion potential, and oxidative stress that are known to aid in the carcinogenic process. METHODS: To perform this study, we generated three different HaCaT cell lines using retroviral transduction that stably expressed combinations of HPV-18 oncogenes that included HaCaT E5-18, HaCaT E6/E7-18, and HaCaT E5/E6/E7-18. FINDINGS: Our results revealed a statistically significant increment in cell viability as measured by MTT assay, cell proliferation, and invasion assays in the cell line containing the three viral oncogenes. Additionally, we observed that cells expressing HPV-18 E5/E6/E7 exhibited a decrease in catalase activity and a significant augmentation of GSH and PRX1 levels relative to those of E5, E6/E7, and HaCaT cells. MAIN CONCLUSIONS: This study demonstrates for the first time that HPV-18 E5, E6, and E7 oncoproteins can cooperate to enhance malignant transformation.


Asunto(s)
Transformación Celular Viral/genética , Proteínas de Unión al ADN/metabolismo , Papillomavirus Humano 18/metabolismo , Proteínas Oncogénicas Virales/metabolismo , Línea Celular Tumoral/virología , Proliferación Celular , Supervivencia Celular , Regulación Neoplásica de la Expresión Génica , Humanos , Oxidación-Reducción
16.
J Microbiol Methods ; 165: 105690, 2019 10.
Artículo en Inglés | MEDLINE | ID: mdl-31425714

RESUMEN

This study aimed to assess the feasibility of using RFLP of PCR-amplified 16S rRNA gene (s) by using universal primers 27f/1492r and a combination of three restriction enzymes, AluI, CfoI, and TaqI, for a low-cost, rapid screen for a primarily differentiation of isolates of the complex of aerobic spore-forming bacteria commonly found in honey samples. The described method produced unique and distinguishable patterns to differentiate among 80 isolates belonging to 26 different species of Bacillus, Brevibacillus, Lysinibacillus, Rummeliibacillus, and Paenibacillus reported in honey and other apiarian sources.


Asunto(s)
Técnicas de Tipificación Bacteriana/métodos , ADN Bacteriano/aislamiento & purificación , Bacterias Formadoras de Endosporas/aislamiento & purificación , Miel/microbiología , Reacción en Cadena de la Polimerasa/métodos , Polimorfismo de Longitud del Fragmento de Restricción , ADN Bacteriano/genética , Bacterias Formadoras de Endosporas/clasificación , Bacterias Formadoras de Endosporas/genética , Estudios de Factibilidad , Filogenia , ARN Ribosómico 16S/genética
18.
Adv Exp Med Biol ; 1127: 3-19, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31140168

RESUMEN

This chapter includes an overview of the structure of cell membranes and a review of the permeability of membranes to biologically relevant oxygen and nitrogen reactive species, namely oxygen, singlet oxygen, superoxide, hydrogen peroxide, hydroxyl radical, nitric oxide, nitrogen dioxide, peroxynitrite and also hydrogen sulfide. Physical interactions of these species with cellular membranes are discussed extensively, but also their relevance to chemical reactions such as lipid peroxidation. Most of these species are involved in different cellular redox processes ranging from physiological pathways to damaging reactions against biomolecules. Cell membranes separate and compartmentalize different processes, inside or outside cells, and in different organelles within cells. The permeability of these membranes to reactive species varies according to the physicochemical properties of each molecule. Some of them, such as nitric oxide and oxygen, are small and hydrophobic and can traverse cellular membranes virtually unhindered. Nitrogen dioxide and hydrogen sulfide find a slightly higher barrier to permeation, but still their diffusion is largely unimpeded by cellular membranes. In contrast, the permeability of cellular membranes to the more polar hydrogen peroxide, is up to five orders of magnitude lower, allowing the formation of concentration gradients, directionality and effective compartmentalization of its actions which can be further regulated by specific aquaporins that facilitate its diffusion through membranes. The compartmentalizing effect on anionic species such as superoxide and peroxynitrite is even more accentuated because of the large energetic barrier that the hydrophobic interior of membranes presents to ions that may be overcome by protonation or the use of anion channels. The large difference in cell membrane permeability for different reactive species indicates that compartmentalization is possible for some but not all of them.


Asunto(s)
Permeabilidad de la Membrana Celular , Membrana Celular/metabolismo , Especies de Nitrógeno Reactivo/metabolismo , Especies Reactivas de Oxígeno/metabolismo , Difusión , Óxido Nítrico , Oxidación-Reducción , Superóxidos
19.
Nutrients ; 11(2)2019 Feb 13.
Artículo en Inglés | MEDLINE | ID: mdl-30781889

RESUMEN

Developed countries have shown a time trend towards a younger age at menarche (AAM), which is associated with increased risk of later obesity and non-communicable diseases. This study aimed to assess whether a time trend in AAM is associated with disease risk in Mexican women (n = 30,826), using data from the Mexican National Health Survey (2000). Linear and log binomial regression was used for nutritional and disease outcomes, while Welch⁻ANOVA was used to test for a time trend. AAM (in years) decreased over time (p < 0.001), with a maximal difference of 0.99 years between the 1920s (13.6 years) and 1980s (12.6 years ). AAM was negatively associated with weight (ß = -1.01 kg; 95% CI -1.006, -1.004) and body mass index (BMI) (ß = -1.01 kg/m²; -1.007, -1.006), and positively with height (ß = 0.18 cm; 0.112, 0.231). AAM was associated with diabetes (RR = 0.95; 0.93, 0.98) and hypercholesterolemia (RR = 0.93; 0.90, 0.95), but not with hypertension, breast cancer or arthritis. In Mexico, AAM decreased significantly during the 20th century. AAM was inversely associated with adult weight and BMI, and positively with height. Women with a later AAM had a lower risk of diabetes and hypercholesterolemia.


Asunto(s)
Envejecimiento/fisiología , Menarquia , Enfermedades no Transmisibles/epidemiología , Adolescente , Artritis/epidemiología , Neoplasias de la Mama/epidemiología , Femenino , Humanos , México/epidemiología , Obesidad , Factores de Tiempo
20.
Int J Obes (Lond) ; 43(5): 999-1008, 2019 05.
Artículo en Inglés | MEDLINE | ID: mdl-29907846

RESUMEN

BACKGROUND/OBJECTIVE: Iron deficiency (ID) is common in overweight and obese individuals (OW/OB) but the mechanism is uncertain. Greater blood volume (BV) in OW/OB may increase hemoglobin (Hb) mass and iron requirements, and confound iron biomarkers by hemodilution. Quantification of BV/PV changes in OW/OB is challenging and a formula to estimate BV/PV based on anthropometric indices would be valuable. In normal weight (NW) and OW/OB women, we aimed at: (1) measure BV and assess whether differences in BV affect concentrations and total circulating mass of Hb and iron biomarkers; (2) develop an algorithm describing BV in OW/OB. SUBJECTS/METHODS: In a cross-sectional study, we measured BV in NW, OW, and OB non-anemic women (n = 62) by using the carbon monoxide-rebreathing method, body composition by dual energy X-ray absorptiometry, and iron and inflammatory status. RESULTS: OW and OB women had 11 and 16% higher mean BV and PV compared to NW (P < 0.05), respectively. In OW/OB compared to NW, total circulating masses of IL-6, hepcidin, Hb, and sTfR were higher, while total mass of serum iron was lower (for all, P < 0.05). An equation including height, body mass and lean mass to estimate BV in all BMI groups (R2 = 0.76). CONCLUSION: An equation based on anthropometric indices provides a good estimate of increased BV in OW/OB women. In OW/OB women, there is an increase in Hb mass that likely increases iron requirements for erythropoiesis and circulating TfR mass. At the same time, higher hepcidin concentrations may lower serum iron mass. Both these mechanisms may increase risk for ID in OW/OB women.


Asunto(s)
Anemia Ferropénica/metabolismo , Volumen Sanguíneo/fisiología , Monóxido de Carbono/metabolismo , Carboxihemoglobina/análisis , Hierro/metabolismo , Obesidad/metabolismo , Absorciometría de Fotón , Adulto , Anemia Ferropénica/fisiopatología , Biomarcadores/metabolismo , Determinación del Volumen Sanguíneo , Índice de Masa Corporal , Carboxihemoglobina/metabolismo , Estudios Transversales , Femenino , Humanos , Obesidad/fisiopatología , Reproducibilidad de los Resultados , Respiración , Adulto Joven
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA