Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 29
Filtrar
1.
Ecol Evol ; 14(4): e11168, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38571793

RESUMO

Avian nests are fundamental structures in avian reproduction and face strong selective forces. Climatic conditions are likely to have shaped the evolution of specific nest traits, but evidence is scarce at a macroevolutionary level. The Thraupidae family (commonly known as tanagers) is an ideal clade to understand the link between nest architecture and climate because it presents wide variation in nest traits. To understand whether climatic variables have played a role in the diversification of nest traits among species in this family, we measured nests from 49 species using museum collections. We observed that dome-nesting species are present in dryer and hotter environments, in line with previous findings suggesting that domed nests are a specialisation for arid conditions. We also found evidence that nests with thicker walls are present in locations with lower precipitation and that solar radiation can influence the shape of domed nests; birds tend to build shorter and narrower domes in areas with high levels of solar radiation. Open nest architecture is also potentially influenced by wind speed, with longer and deeper nests in areas characterised by strong winds. Our results support the hypothesis that different climatic variables can drive the evolution of specific aspects of nest architecture and contribute to the diversity of nest shapes we currently observe. However, climatic variables account only for a small fraction of the observed structural variation, leaving a significant portion still unexplained.

2.
J Healthc Manag ; 68(6): 420-426, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37944173

RESUMO

GOAL: This article describes the development and implementation of a behavior intervention response team (BIRT). Pilot data indicate the successful implementation of BIRT interventions with patients and families and the positive staff response to these interventions. METHODS: Patient- and family-disruptive behaviors are increasing in hospitals. Those behaviors arise from stress, financial burdens, and the mental weight of the patient's medical condition on the family. These distressed patients and their families tax an already overwhelmed staff, exacerbating the caregivers' exhaustion, depersonalization, and frustration. We recognized the need to proactively address these disruptions at our children's hospital with an interdisciplinary response. Disciplines engaged in the BIRT development included risk management, behavioral health, child life, service excellence, patient and family services, social work, and chaplaincy. Following multiple brainstorming sessions, we created a comprehensive, clear intervention strategy to engage with a disruptive patient or family. The BIRT was developed to work with both the family and their medical team to intervene at the first signs of potential disruption. PRINCIPAL FINDINGS: With the BIRT, we were able to reduce disruptive behaviors and limit the subsequent removal of problematic individuals from the facility. Of the families who worked with the BIRT, 75.8% required no postintervention follow-up. PRACTICAL APPLICATIONS: The development of a BIRT can help head off disruptive behaviors and improve family-medical team relationships to support the highest quality and safest healthcare.


Assuntos
Comportamento Problema , Criança , Humanos , Criança Hospitalizada , Equipe de Assistência ao Paciente , Família
3.
Int J Consum Stud ; 47(1): 59-73, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36718291

RESUMO

Many individuals have been reluctant to follow the COVID-19 prevention guidelines (e.g., wearing a mask, physical distancing, and vigilant handwashing) set forth by the U.S. Center for Disease Control to reduce the spread of COVID-19. In this research, we use reciprocal altruism theory to investigate the role of loneliness and its impact on compliance with these guidelines. Our findings indicate that lonely individuals are less willing to comply with COVID-19 prevention guidelines than non-lonely individuals. Process evidence suggests that this occurs as loneliness can inhibit an individual's sense of obligation to reciprocate to others. However, we demonstrate that framing information about COVID-19 through agentic (vs. communal) advertising messaging strategies can offset the negative impact of loneliness on compliance with COVID-19 prevention guidelines. Thus, marketers and policymakers may want to consider the important role of loneliness when tailoring messaging appeals that encourage compliance with COVID-19 prevention guidelines.

4.
J Bus Ethics ; : 1-20, 2022 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-36187727

RESUMO

Sustainable products are engineered to reduce environmental, ecological, and human costs of consumption. Not all consumers value sustainable products, however, and this poses negative societal implications. Using self-expansion theory as a guide, we explore how an individual's general sense of belonging-or the perception that one is accepted and valued by others in the broader social world-alters their responses to sustainable products. Five experimental studies and a field study demonstrate that individuals lower in belonging respond less favorably to sustainable products in terms of evaluations and willingness to pay than individuals higher in belonging. Process evidence shows that the extent to which individuals low in belonging perceive that collective, sustainable choices will impact them personally drives this result and that belonging does not impact responses to conventional (i.e., non-sustainable) products. However, perceiving a shared human experience-or that individuals share some important, basic similarities with all people-attenuates the negative effect of low belonging on responses to sustainable products for consumers both low and high in belonging. This research has significant implications for businesses and society given the growing sense of disconnect in modern society. Supplementary Information: The online version contains supplementary material available at 10.1007/s10551-022-05257-0.

6.
Arch Bone Jt Surg ; 6(3): 176-188, 2018 May.
Artigo em Inglês | MEDLINE | ID: mdl-29911134

RESUMO

BACKGROUND: There is a general consensus on the management of femoral fractures in children younger than two years and adolescents older than sixteen years. The best treatment for patients younger than sixteen years of age is still debatable. Titanium Elastic Nails (TEN), is widely used with some evidence, nonetheless, we undertook a systematic meta-analysis to assess the efficacy of TEN compared to Spica cast for the management of femoral shaft fracture in children aged between 2 to 16 years old. METHODS: A computer literature search of PubMed, Scopus, Web of Science, CINAHL and Cochrane Central was conducted using relevant keywords. We included clinical trials and observational studies that compared TEN versus Spica cast; Records were screened for eligible studies and data were extracted and synthesized using Review Manager version 5.3 for Windows. Our search found 573 unique articles. After screening the abstract and relevant full text, 12 studies with a total of 1012 patients were suitable for the final analysis. RESULTS: In terms terms of union (in weeks), the reported effect sizes favoured the TEN group in two included studies only. Moreover, the overall standardized mean difference in sagittal (SMD -0.48, 95% CI [-0.70 to -0.26], P<0.001) and coronal angulations (SMD -0.66, 95% CI [-1.00 to -0.31], P<0.001) favored TEN fixation in management of femoral fractures younger than 16 years. The reported length of hospital stay was not consistent across studies. The overall risk ratio of malalignment (RR=0.39, 95% CI [0.27 to 0.57], P<0.001) favored the TEN as well as walking independently. Based on our analysis, TEN treatment is superior to traction and hip spica for femoral fractures in patients younger than 16 years old. CONCLUSION: Based on our analysis we recommend the use of TEN fixation in management of pediatric femoral fractures in patients younger than 16 years.

7.
SAE Int J Fuels Lubr ; 11(4): 469-482, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30931085

RESUMO

As part of an ongoing assessment of the potential for reducing greenhouse gas emissions of light-duty vehicles, the U.S. Environmental Protection Agency (EPA) has implemented an updated methodology for applying the results of full vehicle simulations to the range of vehicles across the entire fleet. The key elements of the updated methodology explored for this paper, responsive to stakeholder input on the EPA's fleet compliance modeling, include 1) greater transparency in the process used to determine technology effectiveness, and 2) a more direct incorporation of full vehicle simulation results. This paper begins with a summary of the methodology for representing existing technology implementations in the baseline fleet using EPA's Advanced Light-duty Powertrain (ALPHA) full vehicle simulation. To characterize future technologies, a full factorial ALPHA simulation of every conventional technology combination to be considered was conducted. The vehicle simulation results were used to automatically generate response surface equations (RSEs), enabling the use of a quick and easily implemented set of specific equations to estimate fleet-wide emissions in place of running time consuming full vehicle simulations for each potential technology package applied to each model in the fleet. Since the regressions were not extended to represent technology combinations that were not actually simulated, the emissions estimates produced from the RSEs match the ALPHA simulation results with a high degree of conformity. For each vehicle in the fleet, the reduction in emissions for a future technology package can be estimated using RSEs associated with the initial and final technology packages, and considering the particular vehicle's weight, road load, and power. As part of the effectiveness assessment based on weight, road load, and power, this paper will also examine the effect of performance changes in the vehicles.

8.
Injury ; 48(6): 1155-1158, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28325670

RESUMO

OBJECTIVES: To determine if early surgery before 12h confers a survival or length of stay benefit for patients with neck of femur (NOF) fractures. DESIGN: Retrospective review of prospectively collected data. SETTING: District general hospital. PATIENTS: 1913 patients aged over 60 admitted with a fractured NOF who underwent surgery between 2011 and 2015. Mean age was 83.9 years. 73.7% were female. INTERVENTION: Patients had surgery for fractured NOF with data collected on demographics, mortality and length of stay. MAIN OUTCOME MEASUREMENTS: Data collected included gender, age, ASA grade, fracture anatomy, surgery, time to surgery, days spent in acute hospital and rehabilitation settings and 30-day mortality. Statistical analysis was used to identify independent predictors of mortality and length of stay. RESULTS: 30-day mortality was 6.1% and the mean hospitalisation time was 13±11.3days for the acute hospital and 20.2±17.2days for the trust. Operations were performed at a mean of 23.8±14.8h after presentation. Age, gender, ASA grade and type of fracture were independent predictors of either mortality or length of stay. Timing of surgery had an association with mortality but this only reached statistical significance at 24h. In line with previous studies we analysed time to surgery in 12h blocks. We also used logistic regression, recognizing time as a continuous variable, which revealed that every hour of delay to surgery increased the mortality risk by 1.8%. CONCLUSIONS: While every hour of delay increased mortality risk, the association with mortality only became statistically significant when delaying over 24h. This supports a pragmatic approach, with surgery as soon as medically possible without a race to theatre. LEVEL OF EVIDENCE: Level III retrospective cohort study.


Assuntos
Fraturas do Colo Femoral/cirurgia , Fixação Interna de Fraturas , Hospitais Gerais , Tempo de Internação/estatística & dados numéricos , Tempo para o Tratamento/estatística & dados numéricos , Idoso , Idoso de 80 Anos ou mais , Feminino , Fraturas do Colo Femoral/mortalidade , Fraturas do Colo Femoral/fisiopatologia , Fraturas do Colo Femoral/reabilitação , Fixação Interna de Fraturas/mortalidade , Fixação Interna de Fraturas/reabilitação , Serviços de Saúde para Idosos , Mortalidade Hospitalar , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Fatores de Risco , Resultado do Tratamento , Reino Unido
12.
Curr Heart Fail Rep ; 10(1): 36-45, 2013 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-23114591

RESUMO

The symptoms and signs constituting the congestive heart failure (CHF) syndrome have their pathophysiologic origins rooted in a salt-avid renal state mediated by effector hormones of the renin-angiotensin-aldosterone and adrenergic nervous systems. Controlled clinical trials, conducted over the past decade in patients having minimally to markedly severe symptomatic heart failure, have demonstrated the efficacy of a pharmacologic regimen that interferes with these hormones, including aldosterone receptor binding with either spironolactone or eplerenone. Potential pathophysiologic mechanisms, which have not hitherto been considered involved for the salutary responses and cardioprotection provided by these mineralocorticoid receptor antagonists, are reviewed herein. In particular, we focus on the less well-recognized impact of catecholamines and aldosterone on monovalent and divalent cation dyshomeostasis, which leads to hypokalemia, hypomagnesemia, ionized hypocalcemia with secondary hyperparathyroidism and hypozincemia. Attendant adverse cardiac consequences include a delay in myocardial repolarization with increased propensity for supraventricular and ventricular arrhythmias, and compromised antioxidant defenses with increased susceptibility to nonischemic cardiomyocyte necrosis.


Assuntos
Cardiotônicos/uso terapêutico , Insuficiência Cardíaca/tratamento farmacológico , Antagonistas de Receptores de Mineralocorticoides/uso terapêutico , Antioxidantes/fisiologia , Insuficiência Cardíaca/fisiopatologia , Humanos , Neurotransmissores/fisiologia , Estresse Oxidativo/fisiologia , Zinco/fisiologia
13.
J Orthop Surg Res ; 7: 4, 2012 Jan 26.
Artigo em Inglês | MEDLINE | ID: mdl-22280557

RESUMO

BACKGROUND: Distal radius fracture is a common injury with a variety of operative and non-operative management options. There remains debate as to the optimal treatment for a given patient and fracture. Despite the popularity of volar locking plate fixation, there are few large cohort or long term follow up studies to justify this modality. Our aim was to report the functional outcome of a large number of patients at a significant follow up time after fixation of their distal radius with a volar locking plate. METHODS: 180 patients with 183 fractures and a mean age of 62.4 years were followed up retrospectively at a mean of 30 months (Standard deviation=10.4). Functional assessment was performed using the Disabilities of the Arm, Shoulder and Hand (DASH) and modified MAYO wrist scores. Statistical analysis was performed to identify possible variables affecting outcome and radiographs were assessed to determine time to fracture union. RESULTS: The median DASH score was 2.3 and median MAYO score was 90 for the whole group. Overall, 133 patients (74%) had a good or excellent DASH and MAYO score. Statistical analysis showed that no specific variable including gender, age, fracture type, post-operative immobilisation or surgeon grade significantly affected outcome. Complications occurred in 27 patients (15%) and in 11 patients were major (6%). CONCLUSION: This single centre large population series demonstrates good to excellent results in the majority of patients after volar locking plate fixation of the distal radius, with complication rates comparable to other non-operative and operative treatment modalities. On this basis we recommend this mode of fixation for distal radius fractures requiting operative intervention.


Assuntos
Fixação Interna de Fraturas/métodos , Fraturas do Rádio/cirurgia , Traumatismos do Punho/cirurgia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Placas Ósseas , Avaliação da Deficiência , Feminino , Seguimentos , Fixação Interna de Fraturas/efeitos adversos , Fixação Interna de Fraturas/instrumentação , Consolidação da Fratura , Humanos , Masculino , Pessoa de Meia-Idade , Placa Palmar/cirurgia , Radiografia , Fraturas do Rádio/diagnóstico por imagem , Fraturas do Rádio/reabilitação , Recuperação de Função Fisiológica , Estudos Retrospectivos , Resultado do Tratamento , Traumatismos do Punho/diagnóstico por imagem , Traumatismos do Punho/reabilitação , Articulação do Punho/fisiologia , Adulto Jovem
14.
J Orthop Surg Res ; 6: 37, 2011 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-21771311

RESUMO

BACKGROUND: We reviewed our results and complications of using a pre-bent 1.6 mm Kirschner wire (K-wire) for extra-articular metacarpal fractures. The surgical procedure was indicated for angulation at the fracture site in a true lateral radiograph of at least 30 degrees and/or in the presence of a rotatory deformity. METHODS: A single K-wire is pre-bent in a lazy-S fashion with a sharp bend at approximately 5 millimeters and a longer smooth curve bent in the opposite direction. An initial entry point is made at the base of the metacarpal using a 2.5 mm drill by hand. The K-wire is inserted blunt end first in an antegrade manner and the fracture reduced as the wire is passed across the fracture site. With the wire acting as three-point fixation, early mobilisation is commenced at the metacarpo-phalangeal joint in a Futuro hand splint. The wire is usually removed with pliers post-operatively at four weeks in the fracture clinic. RESULTS: We studied internal fixation of 18 little finger and 2 ring finger metacarpal fractures from November 2007 to August 2009. The average age of the cohort was 25 years with 3 women and 17 men. The predominant mechanism was a punch injury with 5 diaphyseal and 15 metacarpal neck fractures. The time to surgical intervention was a mean 13 days (range 4 to 28 days). All fractures proceeded to bony union. The wire was extracted at an average of 4.4 weeks (range three to six weeks). At an average follow up of 8 weeks, one fracture had to be revised for failed fixation and three superficial wound infections needed antibiotic treatment. CONCLUSIONS: With this simple and minimally invasive technique performed as day-case surgery, all patients were able to start mobilisation immediately. The general outcome was good hand function with few complications.


Assuntos
Pinos Ortopédicos , Fixação Intramedular de Fraturas/instrumentação , Fixação Intramedular de Fraturas/métodos , Fraturas Ósseas/cirurgia , Ossos Metacarpais/lesões , Adulto , Antibacterianos/uso terapêutico , Fios Ortopédicos , Estudos de Coortes , Feminino , Seguimentos , Consolidação da Fratura/fisiologia , Fraturas Ósseas/diagnóstico por imagem , Fraturas Ósseas/fisiopatologia , Humanos , Incidência , Masculino , Radiografia , Estudos Retrospectivos , Infecção da Ferida Cirúrgica/tratamento farmacológico , Infecção da Ferida Cirúrgica/epidemiologia , Resultado do Tratamento
15.
Am J Med Sci ; 342(2): 129-34, 2011 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-21747281

RESUMO

The progressive nature of heart failure is linked to multiple factors, including an ongoing loss of cardiomyocytes and necrosis. Necrotic cardiomyocytes leave behind several footprints: the spillage of their contents leading to elevations in serum troponins; and morphologic evidence of tissue repair with scarring. The pathophysiologic origins of cardiomyocyte necrosis relates to neurohormonal activation, including the adrenergic nervous system. Catecholamine-initiated excessive intracellular Ca accumulation and mitochondria Ca overloading in particular initiate a mitochondriocentric signal-transducer-effector pathway to necrosis and which includes the induction of oxidative stress and opening of their inner membrane permeability transition pore. Hypokalemia, ionized hypocalcemia and hypomagnesemia, where consequent elevations in parathyroid hormone further account for excessive intracellular Ca accumulation, hypozincemia and hyposelenemia each compromise metalloenzyme-based antioxidant defenses. The necrotic loss of cardiomyocytes and adverse structural remodeling of myocardium is related to the central role played by a mitochondriocentric pathway initiated by neurohormonal activation.


Assuntos
Miócitos Cardíacos/metabolismo , Estresse Oxidativo/fisiologia , Troponina/sangue , Animais , Fibrose , Humanos , Hiperparatireoidismo Secundário/metabolismo , Hiperparatireoidismo Secundário/fisiopatologia , Miócitos Cardíacos/patologia , Miócitos Cardíacos/fisiologia , Necrose , Troponina/metabolismo , Troponina/fisiologia
16.
Hypertens Res ; 33(11): 1091-101, 2010 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-20827279

RESUMO

Inappropriately (relative to dietary Na(+)) elevated plasma aldosterone concentrations (PAC), or aldosteronism, have been incriminated in both the appearance of the cardiometabolic syndrome (CMS) and its progressive nature. The deleterious dual consequences of elevated PAC and dietary Na(+) have been linked to several components of the CMS, including salt-sensitive hypertension. Moreover, their adverse consequences are considered to be synergistic, culminating in a pro-oxidant phenotype with oxidative injury involving the heart and systemic tissues, including peripheral blood mononuclear cells (PBMC). Our experimental studies in rats receiving aldosterone/salt treatment have identified a common pathogenic event that links aldosteronism to the induction of oxidative stress. Herein, we review these findings and the important role of excessive intracellular Ca(2+) accumulation (EICA), or intracellular Ca(2+) overloading, which occurs in the heart and PBMC, leading to, respectively, cardiomyocyte necrosis with a replacement fibrosis and an immunostimulatory state with consequent coronary vasculopathy. The origin of EICA is based on elevations in plasma parathyroid hormone, which are integral to the genesis of secondary hyperparathyroidism that accompanies aldosteronism and occurs in response to plasma-ionized hypocalcemia and hypomagnesemia whose appearance is the consequence of marked urinary and fecal excretory losses of Ca(2+) and Mg(2+). In addition, we found intracellular Ca(2+) overloading to be intrinsically coupled to a dyshomeostasis of intracellular Zn(2+), which together regulate the redox state of cardiac myocytes and mitochondria via the induction of oxidative stress and generation of antioxidant defenses, respectively. To validate our hypothesis, a series of site-directed, sequential pharmacological and/or nutriceutical interventions targeted along cellular-molecular cascades were carried out to either block downstream events leading to the pro-oxidant phenotype or to enhance antioxidant defenses. In each case, the interventions were found to be cardioprotective. These cumulative salutary responses raise the prospect that pharmacological agents and nutriceuticals capable of influencing extra- and intracellular Ca(2+) and Zn(2+) equilibrium could prevent adverse cardiac remodeling and thereby enhance the management of aldosteronism.


Assuntos
Aldosterona/metabolismo , Cálcio/metabolismo , Hiperaldosteronismo/metabolismo , Estresse Oxidativo , Animais , Vasos Coronários/metabolismo , Vasos Coronários/patologia , Modelos Animais de Doenças , Miocárdio/metabolismo , Miocárdio/patologia , Miócitos Cardíacos/metabolismo , Miócitos Cardíacos/patologia , Necrose , Ratos , Sódio/metabolismo , Vasculite/metabolismo , Vasculite/patologia , Zinco/metabolismo
17.
Am J Med Sci ; 339(1): 31-5, 2010 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-20057275

RESUMO

BACKGROUND: In patients hospitalized with decompensated biventricular failure having hypoalbuminemia and lymphocytopenia without underlying hepatic or renal disease, we addressed the presence of a protein-losing enteropathy (PLE). METHODS: We studied 78 patients having a dilated cardiomyopathy, who were hospitalized with congestive heart failure (CHF) and hypoalbuminemia of uncertain origin. In the first 19 patients, we investigated the presence of PLE using Tc-Dex scintigraphy together with serum albumin 2 to 4 weeks later when compensation had been restored. In the next 59 patients, presenting with reduced serum albumin and relative lymphocyte count at admission, these parameters were again monitored (2-4 weeks) later when symptoms and signs of CHF had resolved. RESULTS: PLE, documented by Tc-Dex(70) scintigraphy, was found in 10 of 19 patients and whose hypoalbuminemia (2.7 +/- 0.1 g/dL, mean +/- standard error of mean) were corrected (3.3 +/- 0.1 g/dL; P < 0.05) with the resolution of CHF, whereas in the 9 patients without a PLE, reduced baseline serum albumin (2.6 +/- 0.1 g/dL) failed to improve on follow-up (2.6 +/- 0.2 g/dL) in keeping with malnutrition. Relative lymphocyte count was reduced (14.6 +/- 1.5%) in patients with PLE but was normal (21.4 +/- 3.3%; P < 0.05) in those without PLE. Serum albumin and relative lymphocyte count were each reduced at admission (2.8 +/- 0.1 g/dL and 14.4 +/- 1.0%, respectively) in 59 patients and increased (P < 0.05) to normal values (3.5 +/- 0.1 g/dL and 24.9 +/- 1.0%) 2 to 4 weeks after they were compensated. CONCLUSIONS: Enteral losses of albumin and lymphocytes account for the reversible hypoalbuminemia and lymphocytopenia found in patients hospitalized with CHF having splanchnic congestion.


Assuntos
Insuficiência Cardíaca/diagnóstico por imagem , Hipoalbuminemia/diagnóstico por imagem , Linfopenia/diagnóstico por imagem , Adulto , Idoso , Idoso de 80 Anos ou mais , Cardiomiopatia Dilatada/complicações , Cardiomiopatia Dilatada/diagnóstico por imagem , Feminino , Seguimentos , Insuficiência Cardíaca/complicações , Humanos , Hipoalbuminemia/complicações , Linfopenia/complicações , Masculino , Pessoa de Meia-Idade , Enteropatias Perdedoras de Proteínas/complicações , Enteropatias Perdedoras de Proteínas/diagnóstico por imagem , Cintilografia
18.
J Am Coll Nutr ; 29(6): 563-74, 2010 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-21677120

RESUMO

Neurohormonal activation involving the hypothalamic-pituitary-adrenal axis and adrenergic nervous and renin-angiotensin-aldosterone systems is integral to stressor state-mediated homeostatic responses. The levels of effector hormones, depending upon the degree of stress, orchestrate the concordant appearance of hypokalemia, ionized hypocalcemia and hypomagnesemia, hypozincemia, and hyposelenemia. Seemingly contradictory to homeostatic responses wherein the constancy of extracellular fluid would be preserved, upregulation of cognate-binding proteins promotes coordinated translocation of cations to injured tissues, where they participate in wound healing. Associated catecholamine-mediated intracellular cation shifts regulate the equilibrium between pro-oxidants and antioxidant defenses, a critical determinant of cell survival. These acute and chronic stressor-induced iterations in extracellular and intracellular cations are collectively referred to as the cation crossroads. Intracellular cation shifts, particularly excessive accumulation of Ca2+, converge on mitochondria to induce oxidative stress and raise the opening potential of their inner membrane permeability transition pores (mPTPs). The ensuing loss of cationic homeostasis and adenosine triphosphate (ATP) production, together with osmotic swelling, leads to organellar degeneration and cellular necrosis. The overall impact of iterations in extracellular and intracellular cations and their influence on cardiac redox state, cardiomyocyte survival, and myocardial structure and function are addressed herein.


Assuntos
Cátions/metabolismo , Sistema Hipotálamo-Hipofisário/metabolismo , Sistema Hipófise-Suprarrenal/metabolismo , Adenosina Trifosfatases/metabolismo , Antioxidantes/metabolismo , Catecolaminas/metabolismo , Homeostase , Humanos , Hipocalcemia/sangue , Hipocalcemia/metabolismo , Hipopotassemia/sangue , Hipopotassemia/metabolismo , Sistema Hipotálamo-Hipofisário/efeitos dos fármacos , Deficiência de Magnésio/sangue , Mitocôndrias/metabolismo , Miocárdio/metabolismo , Miócitos Cardíacos/metabolismo , Necrose/metabolismo , Neurotransmissores/metabolismo , Estresse Oxidativo , Hormônio Paratireóideo/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Sistema Renina-Angiotensina/fisiologia , Selênio/sangue , Selênio/deficiência , Estresse Fisiológico , Regulação para Cima , Zinco/sangue , Zinco/deficiência
19.
Am J Med Sci ; 338(4): 255-8, 2009 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-19707112

RESUMO

BACKGROUND: In nondiabetic patients hospitalized with multiorgan failure, neurohormonal activation can lead to stress-induced hyperglycemia (>140 mg/dL), as could Mg(2+) and Zn(2+) deficiencies. However, it is currently uncertain whether nondiabetic African Americans (AA) hospitalized with either chronic, decompensated biventricular failure (DecompHF) having hepatic and splanchnic congestion, ionized hypomagnesemia and hypozincemia, or acute left heart failure (LHF) would exhibit hyperglycemia at admission. METHODS: We retrospectively examined admission serum glucose in 77 AA patients without a history of diabetes, who were hospitalized with heart failure. This examination included 41 patients admitted during a 4-month period with chronic DecompHF and whose clinical presentation included findings of expanded intra- and extravascular volumes, together with echocardiographic evidence of marked tricuspid regurgitation and distended inferior vena cava, without respiratory variation. These patients were compared with 14 nondiabetic patients hospitalized during the same time period with acute LHF. We also studied admission serum glucose in 22 patients who were admitted with DecompHF having documented hypomagnesemia and hypozincemia. RESULTS: Admission serum glucose (mean +/- standard error of mean) in patients with chronic DecompHF was 105.41 +/- 4.08 mg/dL and was modestly elevated (140-160 mg/dL) in 3 patients. In those with acute LHF, glucose was 94.86 +/- 3.96 mg/dL and did not exceed 140 mg/dL in any patient. Glucose (103.2 +/- 4.3 mg/dL) was not elevated in patients having chronic DecompHF and reduced ionized Mg(2+) and serum Zn(2+) (0.44 +/- 0.01 mmol/L and 69.6 +/- 3.2 mug/dL, respectively). CONCLUSIONS: Hyperglycemia at admission was infrequent in nondiabetic AA patients hospitalized with either acute LHF or chronic DecompHF, which may have also included hypomagnesemia and hypozincemia. This calls into question the need for intensive insulin therapy in these patients.


Assuntos
Negro ou Afro-Americano , Glicemia/análise , Insuficiência Cardíaca/sangue , Diabetes Mellitus , Feminino , Insuficiência Cardíaca/etnologia , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos
20.
Am J Med Sci ; 335(4): 292-7, 2008 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-18414068

RESUMO

BACKGROUND: Factors contributing to heart failure (HF) in African Americans (AA) are under investigation. Reduced 25(OH)D confers increased cardiovascular risk, including HF. METHODS: We monitored serum 25(OH)D, 1,25(OH)2D3, parathyroid hormone (PTH), and creatinine clearance in 102 AA residing in Memphis: 58 hospitalized with decompensated HF of >or=4 weeks in 34 (21 men; 53.3 +/- 1.8 years) or of 1 to 2 weeks in 24 (17 men; 49.6 +/- 2.4 years) and associated with a dilated cardiomyopathy and reduced ejection fraction (<35%); 19 outpatients with compensated HF (14 men; 52.6 +/- 2.7 years) with comparable ejection fraction; 16 outpatients (9 men; 55.4 +/- 2.9 years) with heart disease, but without HF; and 9 healthy volunteers (3 men; 35.8 +/- 3.5 years). RESULTS: Serum 25(OH)D 65 pg/mL was found in all AA with decompensated HF of >or=4 weeks (132.4 +/- 12.0 pg/mL) and 67% with 1 to 2 weeks duration (82.3 +/- 7.9 pg/mL), but only 11% with compensated HF (45.8 +/- 6.1 pg/mL), 12% without HF (29.6 +/- 5.4 pg/mL), and none of the volunteers (31.1 +/- 3.9 pg/mL). Creatinine clearance did not differ between patient groups. CONCLUSIONS: Hypovitaminosis D is prevalent amongst AA residing in Memphis, with or without HF. Elevations in serum PTH in keeping with secondary hyperparathyroidism are only found in AA with decompensated HF, where hypovitaminosis D and other factors are contributory.


Assuntos
Negro ou Afro-Americano , Insuficiência Cardíaca/etiologia , Deficiência de Vitamina D/etnologia , Adulto , Idoso , Calcitriol/sangue , Creatinina/metabolismo , Feminino , Insuficiência Cardíaca/etnologia , Insuficiência Cardíaca/metabolismo , Humanos , Masculino , Pessoa de Meia-Idade , Hormônio Paratireóideo/sangue , Vitamina D/análogos & derivados , Vitamina D/sangue
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...