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1.
Haemophilia ; 30(3): 720-727, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38415392

RESUMEN

INTRODUCTION: Among people with bleeding disorders (PwBD), pain is a major problem and pain treatments are often ineffective. Understanding of psychological factors involved in pain processing is limited. Maladaptive pain attitudes are associated with worse pain outcomes and adaptive pain attitudes are associated with better outcomes in high pain conditions, but relationships between pain attitudes and pain outcomes are so far unexplored among PwBD. AIM: To investigate relationships between pain attitudes and pain outcomes among PwBD. METHODS: Pain attitudes were measured with the Survey of Pain Attitudes, containing two adaptive scales (Control and Emotion) and five maladaptive scales (Disability, Harm, Medication, Solicitude, Medical Cure). Adults with bleeding disorders, who had pain, and were enrolled in Community Voices in Research were eligible. Participants (n = 72) completed an online survey. Cross sectional associations between pain attitudes and pain outcomes (pain and prescribed pain medication use) were investigated using logistic regression. RESULTS: After adjustment for covariates, greater Control attitudes were associated with lower odds of more severe pain, and greater Disability, Harm, and Medication attitudes were all associated with higher odds of more severe pain and with higher odds of any prescribed pain medication use and opioid pain medication use. CONCLUSIONS: We presented compelling evidence of relationships between pain attitudes and pain outcomes in PwBD, though corroboration is needed from other populations. Our findings suggest that modification of pain attitudes presents a possible avenue for interventions to improve pain outcomes and increase patient satisfaction with pain management.


Asunto(s)
Dolor , Humanos , Masculino , Femenino , Adulto , Dolor/psicología , Persona de Mediana Edad , Encuestas y Cuestionarios , Estudios Transversales , Anciano , Adulto Joven
2.
Int J Mol Sci ; 25(4)2024 Feb 06.
Artículo en Inglés | MEDLINE | ID: mdl-38396660

RESUMEN

Bone marrow adipose tissue (BMAT) is hypothesized to serve as an expandable/contractible fat depot which functions, in part, to minimize energy requirements for sustaining optimal hematopoiesis. We investigated whether BMAT is required for immune reconstitution following injury. Male wild type (WBB6F1, WT) and BMAT-deficient WBB6F1/J-KitW/KitW-v/J (KitW/W-v) mice were lethally irradiated. Irradiation was followed by adoptive transfer of 1000 purified WT hematopoietic stem cells (HSCs). The extent of immune reconstitution in blood, bone marrow, and lymph nodes in the irradiated mice was determined using HSCs from green fluorescent protein (GFP)-expressing mice. We also evaluated skeletal response to treatment. Detection of GFP-positive B and T cells in peripheral blood at 4 and 9 weeks following adoptive transfer and in bone marrow and lymph nodes following necropsy revealed excellent immune reconstitution in both WT and BMAT-deficient mice. Adipocytes were numerous in the distal femur of WT mice but absent or rare in KitW/W-v mice. Bone parameters, including length, mass, density, bone volume, microarchitecture, and turnover balance, exhibited few differences between WT and BMAT-deficient mice. The minimal differences suggest that BMAT is not required for reconstitution of the immune system following lethal radiation and is not a major contributor to the skeletal phenotypes of kit signaling-deficient mice.


Asunto(s)
Tejido Adiposo , Médula Ósea , Masculino , Animales , Ratones , Médula Ósea/metabolismo , Tejido Adiposo/metabolismo , Adipocitos/metabolismo , Células Madre Hematopoyéticas , Huesos
3.
Environ Res ; 214(Pt 1): 113845, 2022 11.
Artículo en Inglés | MEDLINE | ID: mdl-35830911

RESUMEN

BACKGROUND: Pregnancy is a sensitive time for maternal cardiovascular functioning and exposures to arsenic or manganese may adversely affect blood pressure (BP). OBJECTIVES: This study examined the associations between arsenic and manganese exposures and maternal BP measured during pregnancy. Effect modification by pre-pregnancy body mass index (BMI) was evaluated. METHODS: Pregnant women (N = 1522) were recruited for a prospective cohort study in Bangladesh (2008-2011). Exposure to arsenic and manganese was measured in drinking water at <16 weeks gestation and toenails at one-month postpartum. Systolic and diastolic BP were measured monthly. Linear mixed models estimated mean BP and differences in mean BP over gestation for arsenic or manganese exposures and adjusted for covariates. RESULTS: Arsenic levels had an increasing dose-response association with maternal BP after 25 weeks gestation. Effect modification was observed for BMI. Participants with lower BMI (<23 kg/m2) exposed to 50 µg/L arsenic had 2.83 mmHg (95% CI:1.74-3.92) greater mean systolic and 1.96 mmHg (95% CI: 1.02-2.91 mmHg) diastolic BP compared to those exposed to ≤ 1 µg/L arsenic at 40 weeks gestation. Participants with higher BMI (≥23 kg/m2) showed a greater mean systolic BP of 5.72 mmHg (95% CI: 3.18-8.27 mmHg) and diastolic BP change of 6.09 mmHg (95% CI: 4.02-8.16 mmHg) at 40 weeks gestation when exposed to 50 µg/L compared to ≤ 1 µg/L arsenic. Participants with lower BMI exposed to drinking water manganese in the 2nd quartile (181-573 µg/L) had 1.04 mmHg higher mean diastolic BP (95% CI: 0.01-2.07 mmHg) at 40 weeks gestation compared to those in the 1st quartile (0.5-180 µg/L). CONCLUSION: Arsenic exposures during pregnancy were consistently associated with increased average maternal systolic and diastolic BP. The effect of manganese on BP was less consistent.


Asunto(s)
Arsénico , Agua Potable , Presión Sanguínea , Femenino , Humanos , Iones , Manganeso , Embarazo , Estudios Prospectivos
4.
BMC Public Health ; 22(1): 498, 2022 03 14.
Artículo en Inglés | MEDLINE | ID: mdl-35287647

RESUMEN

BACKGROUND: Occupational safety and health (OSH) surveillance systems track work-related fatalities, injuries and illnesses as well as the presence of workplace hazards and exposures to inform prevention efforts. Periodic evaluation is critical to the improvement of these systems to meet the demand for more timely, complete, accurate and efficient data processing and analysis. Despite the existence of general guidance for public health surveillance evaluation, no tailored guidance exists for evaluating OSH surveillance systems to date. This study utilized the Delphi technique to collect consensus among experts in the United States on surveillance elements (components, attributes and measures) to inform the development of a tailored evaluation framework. METHODS: A Delphi study approach with three survey rounds invited an expert panel to rate and comment on potential OSH surveillance evaluation framework elements, resulting in an optimal list of elements through the panel's consensus. Additionally, experts completed a review of OSH surveillance systems they worked with and answered questions regarding the development of an evaluation framework. Descriptive statistics of the ratings were compiled for the Delphi process. Major themes from experts' comments were further identified using content analysis to inform contextual information underlying their choices. RESULTS: Fifty-four potential experts across the United States were contacted to participate in the Delphi study. Ten experts began the first survey round with eight then seven experts continuing in the subsequent rounds, respectively. A total of 64 surveillance components, 31 attributes, and 116 example measures were selected into the final list through panel consensus, with 134 (63.5%) reaching high consensus. Major themes regarding current OSH surveillance focused on resources and feasibility, data collection, flexibility, and the inter-relatedness among elements. CONCLUSIONS: A Delphi process identified tailored OSH surveillance elements and major themes regarding OSH surveillance. The identified elements can serve as a preliminary guide for evaluating OSH surveillance systems. A more detailed evaluation framework is under development to incorporate these elements into a standard yet flexible approach to OSH surveillance evaluation.


Asunto(s)
Salud Laboral , Consenso , Técnica Delphi , Humanos , Vigilancia en Salud Pública , Encuestas y Cuestionarios
5.
Int J Mol Sci ; 22(13)2021 Jun 24.
Artículo en Inglés | MEDLINE | ID: mdl-34202651

RESUMEN

Dieting is a common but often ineffective long-term strategy for preventing weight gain. Similar to humans, adult rats exhibit progressive weight gain. The adipokine leptin regulates appetite and energy expenditure but hyperleptinemia is associated with leptin resistance. Here, we compared the effects of increasing leptin levels in the hypothalamus using gene therapy with conventional caloric restriction on weight gain, food consumption, serum leptin and adiponectin levels, white adipose tissue, marrow adipose tissue, and bone in nine-month-old female Sprague-Dawley rats. Rats (n = 16) were implanted with a cannula in the 3rd ventricle of the hypothalamus and injected with a recombinant adeno-associated virus, encoding the rat gene for leptin (rAAV-Lep), and maintained on standard rat chow for 18 weeks. A second group (n = 15) was calorically-restricted to match the weight of the rAAV-Lep group. Both approaches prevented weight gain, and no differences in bone were detected. However, calorically-restricted rats consumed 15% less food and had lower brown adipose tissue Ucp-1 mRNA expression than rAAV-Lep rats. Additionally, calorically-restricted rats had higher abdominal white adipose tissue mass, higher serum leptin and adiponectin levels, and higher marrow adiposity. Caloric restriction and hypothalamic leptin gene therapy, while equally effective in preventing weight gain, differ in their effects on energy intake, energy expenditure, adipokine levels, and body composition.


Asunto(s)
Restricción Calórica , Metabolismo Energético , Terapia Genética , Hipotálamo/metabolismo , Leptina/genética , Adipoquinas/sangre , Adipoquinas/genética , Adipoquinas/metabolismo , Adiponectina/genética , Adiponectina/metabolismo , Tejido Adiposo Blanco/metabolismo , Adiposidad/genética , Animales , Biomarcadores , Peso Corporal , Médula Ósea/metabolismo , Dependovirus/genética , Ingestión de Energía , Metabolismo Energético/genética , Femenino , Expresión Génica , Terapia Genética/métodos , Vectores Genéticos , Leptina/metabolismo , Ratas , Transgenes
6.
Environ Health ; 19(1): 41, 2020 04 10.
Artículo en Inglés | MEDLINE | ID: mdl-32276596

RESUMEN

BACKGROUND: Many populations are exposed to arsenic, lead, and manganese. These metals influence immune function. We evaluated the association between exposure to single and multiple metals, including arsenic, lead, and manganese, to humoral immunity as measured by antibody concentrations to diphtheria and tetanus toxoid among vaccinated Bangladeshi children. Additionally, we examined if this association was potentially mediated by nutritional status. METHODS: Antibody concentrations to diphtheria and tetanus were measured in children's serum at age 5 (n = 502). Household drinking water was sampled to quantify arsenic (W-As) and manganese (W-Mn), whereas lead was measured in blood (B-Pb). Exposure samples were taken during pregnancy, toddlerhood, and early childhood. Multiple linear regression models (MLRs) with single or combined metal predictors were used to determine the association with antibody outcomes. MLR results were transformed to units of percent change in outcome per doubling of exposure to improve interpretability. Structural equation models (SEMs) were used to further assess exposure to metal mixtures. SEMs regressed a latent exposure variable (Metals), informed by all measured metal variables (W-As, W-Mn, and B-Pb), on a latent outcome variable (Antibody), informed by measured antibody variables (diphtheria and tetanus). Weight-for-age z-score (WFA) at age 5 was evaluated as a mediator. RESULTS: Diphtheria antibody was negatively associated with W-As during pregnancy in MLR, but associations were attenuated after adjusting for W-Mn and B-Pb (- 2.9% change in diphtheria antibody per doubling in W-As, 95% confidence interval [CI]: - 7%, 1.5%). Conversely, pregnancy levels of B-Pb were positively associated with tetanus antibody, even after adjusting for W-As and W-Mn (13.3%, 95% CI: 1.7%, 26.3%). Overall, null associations were observed between W-Mn and antibody outcomes. Analysis by SEMs showed that the latent Metals mixture was significantly associated with the latent Antibody outcome (ß = - 0.16, 95% CI: - 0.26, - 0.05), but the Metals variable was characterized by positive and negative loadings of W-As and B-Pb, respectively. Sex-stratified MLR and SEM analyses showed W-As and B-Pb associations were exclusive to females. Mediation by WFA was null, indicating Metals only had direct effects on Antibody. CONCLUSIONS: We observed significant modulation of vaccine antibody concentrations among children with pregnancy and early life exposures to drinking water arsenic and blood lead. We found distinct differences by child sex, as only females were susceptible to metal-related modulations in antibody levels. Weight-for-age, a nutritional status proxy, did not mediate the association between the metal mixture and vaccine antibody.


Asunto(s)
Anticuerpos Antibacterianos/sangre , Toxoide Diftérico/sangre , Exposición a Riesgos Ambientales/análisis , Inmunidad Humoral , Metales/análisis , Estado Nutricional , Toxoide Tetánico/sangre , Arsénico/análisis , Bangladesh , Preescolar , Agua Potable/análisis , Femenino , Humanos , Lactante , Recién Nacido , Plomo/sangre , Masculino , Manganeso/análisis , Metales/sangre , Embarazo , Estudios Prospectivos
7.
Alcohol Clin Exp Res ; 43(11): 2301-2311, 2019 11.
Artículo en Inglés | MEDLINE | ID: mdl-31479513

RESUMEN

BACKGROUND: Estrogen signaling is essential for the sexual dimorphism of the skeleton, is required for normal bone remodeling balance in adults, and may influence the skeletal response to alcohol. High levels of alcohol consumption lower bone mass in ovary-intact but not ovariectomized (ovx) rats. However, the extremely rapid rate of bone loss immediately following ovx may obscure the effects of alcohol. We therefore determined (i) whether heavy alcohol consumption (35% caloric intake) influences bone in sexually mature ovx rats with established cancellous osteopenia and (ii) whether ICI 182,780 (ICI), a potent estrogen receptor signaling antagonist, alters the skeletal response to alcohol. METHODS: Three weeks following ovx, rats were randomized into 5 groups, (i) baseline, (ii) control + vehicle, (iii) control + ICI, (iv) ethanol (EtOH) + vehicle, or (v) EtOH + ICI, and treated accordingly for 4 weeks. Dual-energy X-ray absorptiometry, microcomputed tomography, blood measurements of markers of bone turnover, and gene expression in femur and uterus were used to evaluate response to alcohol and ICI. RESULTS: Rats consuming alcohol had lower bone mass and increased fat mass. Bone microarchitecture of the tibia and gene expression in femur were altered; specifically, there was reduced accrual of cortical bone, net loss of cancellous bone, and differential expression of 19/84 genes related to bone turnover. Furthermore, osteocalcin, a marker of bone turnover, was lower in alcohol-fed rats. ICI had no effect on weight gain, body composition, or cortical bone. ICI reduced cancellous bone loss and serum CTX-1, a biochemical marker of bone resorption; alcohol antagonized the latter 2 responses. Neither alcohol nor ICI affected uterine weight or gene expression. CONCLUSIONS: Alcohol exaggerated bone loss in ovx rats in the presence or absence of estrogen receptor blockade with ICI. The negligible effect of alcohol on uterus and limited effects of ICI on bone in alcohol-fed ovx rats suggest that estrogen receptor signaling plays a limited role in the action of alcohol on bone in a rat model for chronic alcohol abuse.


Asunto(s)
Enfermedades Óseas Metabólicas/inducido químicamente , Huesos/efectos de los fármacos , Antagonistas del Receptor de Estrógeno/uso terapéutico , Etanol/efectos adversos , Fulvestrant/uso terapéutico , Ovariectomía/efectos adversos , Absorciometría de Fotón , Animales , Densidad Ósea/efectos de los fármacos , Enfermedades Óseas Metabólicas/diagnóstico por imagen , Enfermedades Óseas Metabólicas/prevención & control , Huesos/diagnóstico por imagen , Femenino , Ratas , Ratas Sprague-Dawley , Receptores de Estrógenos/antagonistas & inhibidores , Microtomografía por Rayos X
8.
Alcohol Clin Exp Res ; 43(12): 2494-2503, 2019 12.
Artículo en Inglés | MEDLINE | ID: mdl-31557335

RESUMEN

BACKGROUND: Chronic heavy alcohol consumption is an established risk factor for bone fracture, but comorbidities associated with alcohol intake may contribute to increased fracture rates in alcohol abusers. To address the specific effects of alcohol on bone, we used a nonhuman primate model and evaluated voluntary alcohol consumption on: (i) global markers of bone turnover in blood and (ii) cancellous bone mass, density, microarchitecture, turnover, and microdamage in lumbar vertebra. METHODS: Following a 4-month induction period, 6-year-old male rhesus macaques (Macaca mulatta, n = 13) voluntarily self-administered water or ethanol (EtOH; 4% w/v) for 22 h/d, 7 d/wk, for a total of 12 months. Control animals (n = 9) consumed an isocaloric maltose-dextrin solution. Tetracycline hydrochloride was administered orally 17 and 3 days prior to sacrifice to label mineralizing bone surfaces. Global skeletal response to EtOH was evaluated by measuring plasma osteocalcin and carboxyterminal collagen cross-links (CTX). Local response was evaluated in lumbar vertebra using dual-energy X-ray absorptiometry, microcomputed tomography, static and dynamic histomorphometry, and histological assessment of microdamage. RESULTS: Monkeys in the EtOH group consumed an average of 2.8 ± 0.2 (mean ± SE) g/kg/d of EtOH (30 ± 2% of total calories), resulting in an average blood EtOH concentration of 88.3 ± 8.8 mg/dl 7 hours after the session onset. Plasma CTX and osteocalcin tended to be lower in EtOH-consuming monkeys compared to controls. Significant differences in bone mineral density in lumbar vertebrae 1 to 4 were not detected with treatment. However, cancellous bone volume fraction (in cores biopsied from the central region of the third vertebral body) was lower in EtOH-consuming monkeys compared to controls. Furthermore, EtOH-consuming monkeys had lower osteoblast perimeter and mineralizing perimeter, no significant difference in osteoclast perimeter, and higher bone marrow adiposity than controls. No significant differences between groups were detected in microcrack density (2nd lumbar vertebra). CONCLUSIONS: Voluntary chronic heavy EtOH consumption reduces cancellous bone formation in lumbar vertebra by decreasing osteoblast-lined bone perimeter, a response associated with an increase in bone marrow adiposity.


Asunto(s)
Adiposidad/fisiología , Consumo de Bebidas Alcohólicas/efectos adversos , Médula Ósea/fisiopatología , Hueso Esponjoso/crecimiento & desarrollo , Etanol/efectos adversos , Animales , Densidad Ósea/efectos de los fármacos , Colágeno/sangre , Etanol/sangre , Vértebras Lumbares/efectos de los fármacos , Macaca mulatta , Masculino , Osteocalcina/sangre
9.
J Prim Prev ; 40(3): 279-295, 2019 06.
Artículo en Inglés | MEDLINE | ID: mdl-30895424

RESUMEN

Older adults (> 65) are less physically active than all other adult age groups. Although experiences of weight discrimination have been inversely associated with physical activity in several studies of middle-aged and older adults, the role of weight discrimination in this relationship has not been sufficiently explicated. Using data from the Health and Retirement Study (a longitudinal panel study of U.S. adults aged 50 and older), we hypothesized that, among middle aged and older adults, weight discrimination would (a) be inversely related to respondents' reported level of physical activity; and (b) partially mediate the relationship between BMI and physical activity. Using multiple logistic regression analysis, we found an inverse relationship between weight discrimination and vigorous physical activity (OR = 0.79; 95% CI [0.66, 0.94]), as well as between weight discrimination and moderate physical activity (OR = 0.76; 95% CI [0.62, 0.92]). Weight discrimination mediated 13% of the relationship between BMI and vigorous physical activity, as well as 9% of the relationship between BMI and moderate physical activity. Weight discrimination may thus pose a barrier to regular physical activity among middle aged and older adults. Future research and interventions should identify effective ways of mitigating barriers experienced because of weight discrimination in the promotion of physical activity among these age groups, as well as how we may effectively reduce the perpetration of weight discrimination in various settings.


Asunto(s)
Prejuicio de Peso/psicología , Anciano , Índice de Masa Corporal , Ejercicio Físico , Femenino , Humanos , Entrevistas como Asunto , Estudios Longitudinales , Masculino , Persona de Mediana Edad , Obesidad/psicología , Encuestas y Cuestionarios , Estados Unidos , Prejuicio de Peso/estadística & datos numéricos
10.
Biometrics ; 73(4): 1279-1288, 2017 12.
Artículo en Inglés | MEDLINE | ID: mdl-28378510

RESUMEN

A novel nonparametric regression model is developed for evaluating the covariate-specific accuracy of a continuous biological marker. Accurately screening diseased from nondiseased individuals and correctly diagnosing disease stage are critically important to health care on several fronts, including guiding recommendations about combinations of treatments and their intensities. The accuracy of a continuous medical test or biomarker varies by the cutoff threshold (c) used to infer disease status. Accuracy can be measured by the probability of testing positive for diseased individuals (the true positive probability or sensitivity, Se(c), of the test), and the true negative probability (specificity, Sp(c)) of the test. A commonly used summary measure of test accuracy is the Youden index, YI=max{Se(c)+Sp(c)-1:c∈ℝ}, which is popular due in part to its ease of interpretation and relevance to population health research. In addition, clinical practitioners benefit from having an estimate of the optimal cutoff that maximizes sensitivity plus specificity available as a byproduct of estimating YI. We develop a highly flexible nonparametric model to estimate YI and its associated optimal cutoff that can respond to unanticipated skewness, multimodality, and other complexities because data distributions are modeled using dependent Dirichlet process mixtures. Important theoretical results on the support properties of the model are detailed. Inferences are available for the covariate-specific Youden index and its corresponding optimal cutoff threshold. The value of our nonparametric regression model is illustrated using multiple simulation studies and data on the age-specific accuracy of glucose as a biomarker of diabetes.


Asunto(s)
Teorema de Bayes , Modelos Estadísticos , Estadísticas no Paramétricas , Biomarcadores , Glucemia/análisis , Simulación por Computador , Diabetes Mellitus/diagnóstico , Humanos , Análisis de Regresión , Sensibilidad y Especificidad
11.
Hepatology ; 60(4): 1150-9, 2014 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-24913187

RESUMEN

UNLABELLED: Egypt has the highest hepatitis C virus (HCV) prevalence in the world (14.7%). The drivers of the HCV epidemic in Egypt are not well understood, but the mass parenteral antischistosomal therapy (PAT) campaigns in the second half of the 20th century are believed to be the determinant of the high prevalence. We studied HCV exposure in Egypt at a microscale through spatial mapping and epidemiological description of HCV clustering. The source of data was the 2008 Egypt Demographic and Health Survey. We identified clusters with high and low HCV prevalence and high and low PAT exposure using Kulldorff spatial scan statistics. Correlations across clusters were estimated, and each cluster age-specific HCV prevalence was described. We identified six clusters of high HCV prevalence, three clusters of low HCV prevalence, five clusters of high PAT exposure, and four clusters of low PAT exposure. HCV prevalence and PAT exposure were not significantly associated across clusters (Pearson correlation coefficient [PCC] = 0.36; 95% confidence interval [CI] -0.12 to 0.71). Meanwhile, there was a strong association between HCV prevalence in individuals older than 30 years of age (who could have been exposed to PAT) and HCV prevalence in individuals 30 years of age or younger (who could not have been exposed to PAT) (PCC = 0.81; 95% CI 0.55-0.93). CONCLUSION: The findings illustrate a spatial variation in HCV exposure in Egypt. The observed clustering was suggestive of an array of iatrogenic risk factors, besides past PAT exposure, and ongoing transmission. The role of PAT exposure in the HCV epidemic could have been overstated. Our findings support the rationale for spatially prioritized interventions.


Asunto(s)
Demografía/estadística & datos numéricos , Hepacivirus , Hepatitis C/epidemiología , Enfermedad Iatrogénica/epidemiología , Adolescente , Adulto , Factores de Edad , Análisis por Conglomerados , Egipto/epidemiología , Femenino , Encuestas Epidemiológicas , Humanos , Masculino , Persona de Mediana Edad , Prevalencia , Factores de Riesgo , Esquistosomiasis/complicaciones , Esquistosomiasis/terapia , Adulto Joven
12.
Exp Physiol ; 100(4): 435-49, 2015 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-25664905

RESUMEN

NEW FINDINGS: What is the central question of this study? Is exercise-induced oxidative stress the upstream exercise-related signalling mechanism that leads to sustained postexercise vasodilatation via activation of H1 and H2 histamine receptors? What is the main finding and its importance? Systemic administration of the antioxidant ascorbate inhibits sustained postexercise vasodilatation to the same extent as seen previously with H1 and H2 histamine receptor blockade following small muscle-mass exercise. However, ascorbate has a unique ability to catalyse the degradation of histamine. We also found that systemic infusion of the antioxidant N-acetylcysteine had no effect on sustained postexercise vasodilatation, suggesting that exercise-induced oxidative stress does not contribute to sustained postexercise vasodilatation. An acute bout of aerobic exercise elicits a sustained postexercise vasodilatation that is mediated by histamine H1 and H2 receptor activation. However, the upstream signalling pathway that leads to postexercise histamine receptor activation is unknown. We tested the hypothesis that the potent antioxidant ascorbate would inhibit this histaminergic vasodilatation following exercise. Subjects performed 1 h of unilateral dynamic knee extension at 60% of peak power in three conditions: (i) control; (ii) i.v. ascorbate infusion; and (iii) ascorbate infusion plus oral H1 /H2 histamine receptor blockade. Femoral artery blood flow was measured (using Doppler ultrasound) before exercise and for 2 h postexercise. Femoral vascular conductance was calculated as flow/pressure. Postexercise vascular conductance was greater for control conditions (3.4 ± 0.1 ml min(-1) mmHg(-1) ) compared with ascorbate (2.7 ± 0.1 ml min(-1) mmHg(-1) ; P < 0.05) and ascorbate plus H1 /H2 blockade (2.8 ± 0.1 ml min(-1) mmHg(-1) ; P < 0.05), which did not differ from one another (P = 0.9). Given that ascorbate may catalyse the degradation of histamine in vivo, we conducted a follow-up study, in which subjects performed exercise in two conditions: (i) control; and (ii) i.v. N-acetylcysteine infusion. Postexercise vascular conductance was similar for control (4.0 ± 0.1 ml min(-1) mmHg(-1) ) and N-acetylcysteine conditions (4.0 ± 0.1 ml min(-1) mmHg(-1) ; P = 0.8). Thus, the results in the initial study were due to the degradation of histamine in skeletal muscle by ascorbate, because the histaminergic vasodilatation was unaffected by N-acetylcysteine. Overall, exercise-induced oxidative stress does not appear to contribute to sustained postexercise vasodilatation.


Asunto(s)
Ejercicio Físico/fisiología , Músculo Esquelético/fisiología , Resistencia Física/fisiología , Receptores Histamínicos H1/metabolismo , Receptores Histamínicos H2/metabolismo , Vasodilatación/fisiología , Antioxidantes/administración & dosificación , Ácido Ascórbico/administración & dosificación , Femenino , Agonistas de los Receptores Histamínicos/administración & dosificación , Humanos , Masculino , Músculo Esquelético/efectos de los fármacos , Estrés Oxidativo/efectos de los fármacos , Estrés Oxidativo/fisiología , Resistencia Física/efectos de los fármacos , Regulación hacia Arriba/efectos de los fármacos , Regulación hacia Arriba/fisiología , Vasodilatación/efectos de los fármacos , Adulto Joven
13.
Stat Med ; 34(30): 3997-4015, 2015 Dec 30.
Artículo en Inglés | MEDLINE | ID: mdl-26239173

RESUMEN

A novel semiparametric regression model is developed for evaluating the covariate-specific accuracy of a continuous medical test or biomarker. Ideally, studies designed to estimate or compare medical test accuracy will use a separate, flawless gold-standard procedure to determine the true disease status of sampled individuals. We treat this as a special case of the more complicated and increasingly common scenario in which disease status is unknown because a gold-standard procedure does not exist or is too costly or invasive for widespread use. To compensate for missing data on disease status, covariate information is used to discriminate between diseased and healthy units. We thus model the probability of disease as a function of 'disease covariates'. In addition, we model test/biomarker outcome data to depend on 'test covariates', which provides researchers the opportunity to quantify the impact of covariates on the accuracy of a medical test. We further model the distributions of test outcomes using flexible semiparametric classes. An important new theoretical result demonstrating model identifiability under mild conditions is presented. The modeling framework can be used to obtain inferences about covariate-specific test accuracy and the probability of disease based on subject-specific disease and test covariate information. The value of the model is illustrated using multiple simulation studies and data on the age-adjusted ability of soluble epidermal growth factor receptor - a ubiquitous serum protein - to serve as a biomarker of lung cancer in men. SAS code for fitting the model is provided. Copyright © 2015 John Wiley & Sons, Ltd.


Asunto(s)
Modelos Estadísticos , Análisis de Regresión , Teorema de Bayes , Biomarcadores de Tumor/sangre , Bioestadística , Simulación por Computador , Receptores ErbB/sangre , Humanos , Neoplasias Pulmonares/sangre , Neoplasias Pulmonares/diagnóstico , Masculino , Curva ROC , Medición de Riesgo/estadística & datos numéricos
14.
Alcohol Clin Exp Res ; 38(5): 1365-72, 2014 May.
Artículo en Inglés | MEDLINE | ID: mdl-24512198

RESUMEN

BACKGROUND: Bone health is influenced by numerous lifestyle factors, including diet and exercise. Alcohol is a major nonessential constituent of diet and has dose- and context-dependent effects on bone. Endurance exercise is associated with increased risk of stress fractures. The purpose of this study was to determine the long-term independent and combined effects of chronic heavy alcohol consumption and endurance exercise (treadmill running) on bone mass and microarchitecture in young adult male Sprague-Dawley rats. METHODS: Six-month-old male rats were randomized into 4 groups (9 to 13 rats/group): sedentary + control diet, sedentary + ethanol (EtOH) diet, exercise + control diet, or exercise + EtOH diet. EtOH-fed rats consumed a liquid diet (EtOH comprised 35% of caloric intake) ad libitum. Control rats were pair-fed the same diet with isocaloric substitution of EtOH with maltose-dextran. Exercise was conducted on a motorized treadmill (15% grade for 30 minutes) 5 d/wk for 16 weeks. Femur and 12th thoracic vertebra were analyzed for bone mineral content (BMC) and density (BMD) using densitometry and cortical and cancellous bone architecture using microcomputed tomography. RESULTS: EtOH consumption resulted in lower femur length, BMC, and BMD, and lower midshaft femur cortical volume, cortical thickness, and polar moment of inertia. In addition, trabecular thickness was lower in vertebra of EtOH-fed rats. Endurance exercise had no independent effect on any end point evaluated. A significant interaction between endurance exercise and EtOH was detected for several cancellous end points in the distal femur metaphysis. EtOH-consuming rats that exercised had lower distal femur metaphysis bone volume/tissue volume, trabecular connectivity density, and trabecular thickness compared to exercising rats that consumed control diet. CONCLUSIONS: The results obtained in this model suggest that chronic heavy alcohol consumption may reduce skeletal integrity by reducing bone size, mass, and density, and by negatively altering bone microarchitecture and may increase fracture risk associated with endurance exercise at weight-bearing skeletal sites.


Asunto(s)
Huesos/efectos de los fármacos , Etanol/farmacología , Condicionamiento Físico Animal/fisiología , Absorciometría de Fotón , Animales , Densidad Ósea/efectos de los fármacos , Densidad Ósea/fisiología , Huesos/anatomía & histología , Huesos/fisiología , Etanol/administración & dosificación , Fémur/anatomía & histología , Fémur/efectos de los fármacos , Fémur/fisiología , Masculino , Ratas , Ratas Sprague-Dawley , Vértebras Torácicas/anatomía & histología , Vértebras Torácicas/efectos de los fármacos , Vértebras Torácicas/fisiología , Microtomografía por Rayos X
15.
Am J Ind Med ; 57(7): 826-36, 2014 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-24585666

RESUMEN

BACKGROUND: Workers onboard freezer-trawl (FT) and freezer-longline (FL) vessels in Alaska may be at high risk for fatal and non-fatal injuries. METHODS: Traumatic occupational injuries onboard vessels in the FT and FL fleets were identified through two government data sources. RESULTS: The annual risk of fatal injuries was 125 per 100,000 FTEs in the FT fleet, and 63 per 100,000 FTEs in the FL fleet. The annual risk of non-fatal injuries was 43 per 1,000 FTEs in the FT fleet and 35 per 1,000 FTEs in the FL fleet. The majority of injuries in the FT fleet occurred in the factories and freezer holds, whereas the most common injuries in the FL fleet occurred on deck while working the fishing gear. CONCLUSIONS: The findings confirmed that workers in those fleets were at high risk for work-related injuries. Injury prevention should focus on removing hazards in the work processes injuring the most workers.


Asunto(s)
Accidentes de Trabajo/estadística & datos numéricos , Traumatismos Ocupacionales/epidemiología , Accidentes de Trabajo/mortalidad , Accidentes de Trabajo/prevención & control , Adolescente , Adulto , Anciano , Alaska/epidemiología , Femenino , Encuestas Epidemiológicas , Humanos , Masculino , Persona de Mediana Edad , Medicina Naval , Traumatismos Ocupacionales/etiología , Traumatismos Ocupacionales/mortalidad , Traumatismos Ocupacionales/prevención & control , Factores de Riesgo , Navíos , Adulto Joven
16.
Bone Rep ; 21: 101769, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38706522

RESUMEN

The hypothalamus and dorsal vagal complex (DVC) are both important for integration of signals that regulate energy balance. Increased leptin transgene expression in either the hypothalamus or DVC of female rats was shown to decrease white adipose tissue and circulating levels of leptin and adiponectin. However, in contrast to hypothalamus, leptin transgene expression in the DVC had no effect on food intake, circulating insulin, ghrelin and glucose, nor on thermogenic energy expenditure. These findings imply different roles for hypothalamus and DVC in leptin signaling. Leptin signaling is required for normal bone accrual and turnover. Leptin transgene expression in the hypothalamus normalized the skeletal phenotype of leptin-deficient ob/ob mice but had no long-duration (≥10 weeks) effects on the skeleton of leptin-replete rats. The goal of this investigation was to determine the long-duration effects of leptin transgene expression in the DVC on the skeleton of leptin-replete rats. To accomplish this goal, we analyzed bone from three-month-old female rats that were microinjected with recombinant adeno-associated virus encoding either rat leptin (rAAV-Leptin, n = 6) or green fluorescent protein (rAAV-GFP, control, n = 5) gene. Representative bones from the appendicular (femur) and axial (3rd lumbar vertebra) skeleton were evaluated following 10 weeks of treatment. Selectively increasing leptin transgene expression in the DVC had no effect on femur cortical or cancellous bone microarchitecture. Additionally, increasing leptin transgene expression had no effect on vertebral osteoblast-lined or osteoclast-lined bone perimeter or marrow adiposity. Taken together, the findings suggest that activation of leptin receptors in the DVC has minimal specific effects on the skeleton of leptin-replete female rats.

17.
Bone ; 185: 117111, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-38679220

RESUMEN

Chronic heavy alcohol consumption is a risk factor for low trauma bone fracture. Using a non-human primate model of voluntary alcohol consumption, we investigated the effects of 6 months of ethanol intake on cortical bone in cynomolgus macaques (Macaca fascicularis). Young adult (6.4 ± 0.1 years old, mean ± SE) male cynomolgus macaques (n = 17) were subjected to a 4-month graded ethanol induction period, followed by voluntary self-administration of water or ethanol (4 % w/v) for 22 h/d, 7 d/wk. for 6 months. Control animals (n = 6) consumed an isocaloric maltose-dextrin solution. Tibial response was evaluated using densitometry, microcomputed tomography, histomorphometry, biomechanical testing, and Raman spectroscopy. Global bone response was evaluated using biochemical markers of bone turnover. Monkeys in the ethanol group consumed an average of 2.3 ± 0.2 g/kg/d ethanol resulting in a blood ethanol concentration of 90 ± 12 mg/dl in longitudinal samples taken 7 h after the daily session began. Ethanol consumption had no effect on tibia length, mass, density, mechanical properties, or mineralization (p > 0.642). However, compared to controls, ethanol intake resulted in a dose-dependent reduction in intracortical bone porosity (Spearman rank correlation = -0.770; p < 0.0001) and compared to baseline, a strong tendency (p = 0.058) for lower plasma CTX, a biochemical marker of global bone resorption. These findings are important because suppressed cortical bone remodeling can result in a decrease in bone quality. In conclusion, intracortical bone porosity was reduced to subnormal values 6 months following initiation of voluntary ethanol consumption but other measures of tibia architecture, mineralization, or mechanics were not altered.


Asunto(s)
Consumo de Bebidas Alcohólicas , Calcificación Fisiológica , Hueso Cortical , Macaca fascicularis , Animales , Masculino , Porosidad , Consumo de Bebidas Alcohólicas/fisiopatología , Hueso Cortical/efectos de los fármacos , Hueso Cortical/patología , Hueso Cortical/diagnóstico por imagen , Calcificación Fisiológica/efectos de los fármacos , Fenómenos Biomecánicos/efectos de los fármacos , Microtomografía por Rayos X , Tibia/efectos de los fármacos , Tibia/diagnóstico por imagen , Tibia/patología , Etanol/farmacología , Espectrometría Raman , Densidad Ósea/efectos de los fármacos
18.
Cancer Invest ; 31(4): 258-72, 2013 May.
Artículo en Inglés | MEDLINE | ID: mdl-23627408

RESUMEN

SELDI-TOF MS analysis of ovarian cyst fluids revealed that peaks m/z 8696 and 8825 discriminate malignant, borderline, and benign tumors. These peaks correspond to isoforms of apoA2. ELISA demonstrates that apoA1, A2, B, C2, C3, and E cyst fluid concentrations are uncorrelated and higher in malignant ovarian tumors, but only apoA2, apoE, and age are independent classifiers of malignant ovarian tumors, yielding 55.1% sensitivity, 95% specificity, and 88.1% accuracy to discern malignant from benign and borderline tumors. These data suggest that lipoprotein metabolism is dysregulated in ovarian cancer and that apoA2 and apoE warrant further investigation as ovarian tumor biomarkers.


Asunto(s)
Apolipoproteínas/metabolismo , Biomarcadores de Tumor/metabolismo , Líquido Quístico/metabolismo , Lipoproteínas/metabolismo , Neoplasias Glandulares y Epiteliales/metabolismo , Quistes Ováricos/metabolismo , Neoplasias Ováricas/metabolismo , Adulto , Anciano , Anciano de 80 o más Años , Carcinoma Epitelial de Ovario , Femenino , Humanos , Persona de Mediana Edad , Adulto Joven
19.
Cancer Invest ; 31(7): 433-53, 2013 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-23915068

RESUMEN

SELDI-TOF MS analysis of cyst fluids identified 95 peaks that discriminate malignant, borderline, and benign ovarian tumors. Three prominent peaks, which correspond to calgranulin A (m/z 10847) and two isoforms of calgranulin B (m/z 12717 and 13294), have higher concentrations in borderline and malignant cyst fluids. Together, calgranulin A and B distinguish borderline and malignant tumors from benign tumors with 28.6% and 63.6% sensitivity for early stage disease, respectively, at 95% specificity and with 74.8% accuracy. Ovarian cyst fluids are useful for discovering discriminatory biomarkers, such as calgranulin, which may have utility for detecting, diagnosing, and biochemically classifying ovarian tumors.


Asunto(s)
Biomarcadores de Tumor/análisis , Calgranulina A/análisis , Calgranulina B/análisis , Quistes Ováricos/química , Neoplasias Ováricas/diagnóstico , Adulto , Anciano , Anciano de 80 o más Años , Western Blotting , Calgranulina A/biosíntesis , Calgranulina B/biosíntesis , Líquido Quístico/química , Electroforesis en Gel de Poliacrilamida , Ensayo de Inmunoadsorción Enzimática , Femenino , Humanos , Persona de Mediana Edad , Neoplasias Ováricas/metabolismo , Isoformas de Proteínas/análisis , Isoformas de Proteínas/biosíntesis , Sensibilidad y Especificidad , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción
20.
Biometrics ; 69(2): 508-19, 2013 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-23489010

RESUMEN

Logistic regression is a popular tool for risk analysis in medical and population health science. With continuous response data, it is common to create a dichotomous outcome for logistic regression analysis by specifying a threshold for positivity. Fitting a linear regression to the nondichotomized response variable assuming a logistic sampling model for the data has been empirically shown to yield more efficient estimates of odds ratios than ordinary logistic regression of the dichotomized endpoint. We illustrate that risk inference is not robust to departures from the parametric logistic distribution. Moreover, the model assumption of proportional odds is generally not satisfied when the condition of a logistic distribution for the data is violated, leading to biased inference from a parametric logistic analysis. We develop novel Bayesian semiparametric methodology for testing goodness of fit of parametric logistic regression with continuous measurement data. The testing procedures hold for any cutoff threshold and our approach simultaneously provides the ability to perform semiparametric risk estimation. Bayes factors are calculated using the Savage-Dickey ratio for testing the null hypothesis of logistic regression versus a semiparametric generalization. We propose a fully Bayesian and a computationally efficient empirical Bayesian approach to testing, and we present methods for semiparametric estimation of risks, relative risks, and odds ratios when parametric logistic regression fails. Theoretical results establish the consistency of the empirical Bayes test. Results from simulated data show that the proposed approach provides accurate inference irrespective of whether parametric assumptions hold or not. Evaluation of risk factors for obesity shows that different inferences are derived from an analysis of a real data set when deviations from a logistic distribution are permissible in a flexible semiparametric framework.


Asunto(s)
Teorema de Bayes , Modelos Logísticos , Simulación por Computador , Humanos , Modelos Estadísticos , Obesidad/etiología , Oportunidad Relativa , Medición de Riesgo/estadística & datos numéricos , Fumar/efectos adversos
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