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1.
Am J Physiol Heart Circ Physiol ; 304(4): H514-28, 2013 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-23241318

RESUMO

Functional differences between subsarcolemmal and interfibrillar cardiac mitochondria (SSM and IFM) have been observed with aging and pathological conditions in rodents. Results are contradictory, and there is little information from large animal models. We assessed the respiratory function and resistance to mitochondrial permeability transition (MPT) in SSM and IFM from healthy young (1 yr) and old (8 yr) female beagles and in old beagles with hypertension and left ventricular (LV) wall thickening induced by 16 wk of aldosterone infusion. MPT was assessed in SSM and IFM by Ca(2+) retention and swelling. Healthy young and old beagles had similar mitochondrial structure, respiratory function, and Ca(2+)-induced MPT within SSM and IFM subpopulations. On the other hand, oxidative capacity and resistance to Ca(2+)-induced MPT were significantly greater in IFM compared with SSM in all groups. Old beagles treated with aldosterone had greater LV wall thickness and worse diastolic filling but normal LV chamber volume and systolic function. Treatment with aldosterone did not alter mitochondrial respiratory function but accelerated Ca(2+)-induced MPT in SSM, but not IFM, compared with healthy old and young beagles. In conclusion, in a large animal model, oxidative capacity and resistance to MPT were greater in IFM than in SSM. Furthermore, aldosterone infusion increased susceptibility to MPT in SSM, but not IFM. Together this suggests that SSM are less resilient to acute stress than IFM in the healthy heart and are more susceptible to the development of pathology with chronic stress.


Assuntos
Envelhecimento/efeitos dos fármacos , Envelhecimento/fisiologia , Aldosterona/efeitos adversos , Permeabilidade da Membrana Celular/efeitos dos fármacos , Permeabilidade da Membrana Celular/fisiologia , Mitocôndrias Cardíacas/efeitos dos fármacos , Mitocôndrias Cardíacas/fisiologia , Aldosterona/administração & dosagem , Animais , Cães , Feminino , Hipertensão/induzido quimicamente , Hipertrofia Ventricular Esquerda/induzido quimicamente , Membranas Intracelulares/efeitos dos fármacos , Membranas Intracelulares/fisiologia
2.
Pacing Clin Electrophysiol ; 36(2): 238-48, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23252749

RESUMO

BACKGROUND: Limited data are available regarding the perioperative management of cardiac rhythm management devices (CRMDs) exposed to intraoperative electromagnetic interference. We postulated that implementation of a simple, standardized approach to CRMD management using our own institution's Pacing And Cardioverting Electronic Devices peri-Operative Protocol (the PACED-OP protocol) would be associated with a reduction in the amount of device reprogramming without an increase in CRMD-related complications. METHODS: Records of patients with CRMDs undergoing 497 consecutive surgical procedures were analyzed retrospectively. Roughly half (51%, n = 254) of these procedures occurred before implementation of the PACED-OP protocol, when patients were generally treated according to the American Society of Anesthesiologists' 2005 guidelines. These cases were compared to the remaining surgeries that occurred after implementation of the PACED-OP protocol. Records were screened for evidence of intraoperative CRMD malfunction that was directly associated with the use of electrocautery. Postoperative complications that could be indirectly or possibly linked to electrocautery-mediated CRMD malfunction were also identified. RESULTS: Implementation of the PACED-OP protocol was associated with a significant reduction in the odds of device reprogramming (adjusted odds ratio [aOR] 0.19, P < 0.001). There was no direct evidence of CRMD malfunction in either cohort. The rate of postoperative complications that could be indirectly or possibly linked with electrocautery-mediated CRMD damage did not differ significantly between cohorts (aOR = 1.37, 95% confidence interval 0.56-3.3, P = 0.49). CONCLUSION: The PACED-OP protocol implementation was associated with a significant reduction in the odds of device reprogramming without a significant difference in the odds of CRMD-related complications.


Assuntos
Algoritmos , Eletrocoagulação/estatística & dados numéricos , Falha de Equipamento/estatística & dados numéricos , Segurança de Equipamentos/estatística & dados numéricos , Marca-Passo Artificial/estatística & dados numéricos , Complicações Pós-Operatórias/epidemiologia , Complicações Pós-Operatórias/prevenção & controle , Idoso , Eletrocoagulação/normas , Segurança de Equipamentos/normas , Feminino , Fidelidade a Diretrizes/estatística & dados numéricos , Humanos , Masculino , Marca-Passo Artificial/normas , Assistência Perioperatória/normas , Assistência Perioperatória/estatística & dados numéricos , Guias de Prática Clínica como Assunto , Estudos Retrospectivos , Tennessee/epidemiologia
3.
Magn Reson Imaging ; 96: 44-49, 2023 02.
Artigo em Inglês | MEDLINE | ID: mdl-36441043

RESUMO

OBJECTIVE: Cardiac implantable electronic devices (CIEDs) have traditionally been a contraindication for magnetic resonance imaging (MRI). However, there is an increasing amount of literature to suggest that MRI can be safely performed in select patients with pacemakers and implantable cardioverter defibrillators by following a standardized protocol. We created an institutional protocol, made accessible as an online form, that is primarily technologist-driven and does not require direct electrophysiologist supervision. The purpose of this study was to evaluate the PACEDMRI protocol for screening and completing MRI in patients with MR conditional CIEDs. SUBJECTS AND METHODS: After the implementation of our standardized PACED-MRI protocol, patients with MR conditional CIEDs who were referred for MRI were included in the study. On the day of the MRI, the device company representative utilized our protocol accessed through PACEDMRI.com. If all parameters and criteria within the protocol were met, the examination proceeded. The device representative programed the CIED to the appropriate mode for MRI as instructed by the PACED-MRI protocol. CIED interrogation was performed immediately before and after MRI. The on-call electrophysiology nurse practitioner was notified only if the protocol instructed the team to not proceed with MRI. CIED programming changes, malfunctions, and intraprocedural events were documented. Additionally, any adverse outcomes were recorded including peri-MRI symptom onset, arrhythmia, and death. RESULTS: One hundred thirty-eight MRI examinations were performed on patients with MR conditional CIEDs (100 pacemakers: 38 implantable cardiac defibrillators). There was no incidence of symptom onset requiring early termination of the MRI, death, or arrhythmic events during or after MRI. No significant changes in lead parameters, including sensing amplitudes, lead thresholds, or lead impedances were noted on post-MRI device interrogation. Out of the 138 completed MRIs, the on-call electrophysiology provider was notified on one, non-urgent occasion. CONCLUSION: The implementation of the standardized, technologists-driven PACED-MRI protocol allowed for a multidisciplinary approach to MRI for patients with MR conditional CIEDs. This study demonstrates that the PACED-MRI protocol can be used for patients with MR conditional CIEDs undergoing MRI without the need for direct electrophysiologist supervision.


Assuntos
Desfibriladores Implantáveis , Marca-Passo Artificial , Humanos , Imageamento por Ressonância Magnética/métodos , Algoritmos , Espectroscopia de Ressonância Magnética
4.
Am J Physiol Endocrinol Metab ; 303(8): E959-72, 2012 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-22829586

RESUMO

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is a common human enzymopathy that affects cellular redox status and may lower flux into nonoxidative pathways of glucose metabolism. Oxidative stress may worsen systemic glucose tolerance and cardiometabolic syndrome. We hypothesized that G6PD deficiency exacerbates diet-induced systemic metabolic dysfunction by increasing oxidative stress but in myocardium prevents diet-induced oxidative stress and pathology. WT and G6PD-deficient (G6PDX) mice received a standard high-starch diet, a high-fat/high-sucrose diet to induce obesity (DIO), or a high-fructose diet. After 31 wk, DIO increased adipose and body mass compared with the high-starch diet but to a greater extent in G6PDX than WT mice (24 and 20% lower, respectively). Serum free fatty acids were increased by 77% and triglycerides by 90% in G6PDX mice, but not in WT mice, by DIO and high-fructose intake. G6PD deficiency did not affect glucose tolerance or the increased insulin levels seen in WT mice. There was no diet-induced hypertension or cardiac dysfunction in either mouse strain. However, G6PD deficiency increased aconitase activity by 42% and blunted markers of nonoxidative glucose pathway activation in myocardium, including the hexosamine biosynthetic pathway activation and advanced glycation end product formation. These results reveal a complex interplay between diet-induced metabolic effects and G6PD deficiency, where G6PD deficiency decreases weight gain and hyperinsulinemia with DIO, but elevates serum free fatty acids, without affecting glucose tolerance. On the other hand, it modestly suppressed indexes of glucose flux into nonoxidative pathways in myocardium, suggesting potential protective effects.


Assuntos
Dieta/efeitos adversos , Frutose/farmacologia , Deficiência de Glucosefosfato Desidrogenase/metabolismo , Coração/fisiologia , Obesidade/fisiopatologia , Acetilglucosamina/metabolismo , Aconitato Hidratase/metabolismo , Adiponectina/sangue , Animais , Peso Corporal/fisiologia , Citrato (si)-Sintase/metabolismo , Ecocardiografia , Eletroforese em Gel de Poliacrilamida , Feminino , Teste de Tolerância a Glucose , Glucosefosfato Desidrogenase/metabolismo , Gônadas/efeitos dos fármacos , Gônadas/crescimento & desenvolvimento , Humanos , Insulina/sangue , Leptina/sangue , Camundongos , Camundongos Endogâmicos C3H , Obesidade/etiologia , Estresse Oxidativo/fisiologia , Triglicerídeos/sangue
5.
Mayo Clin Proc ; 82(3): 318-22, 2007 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-17352368

RESUMO

Electronic article surveillance (EAS) systems are widely implemented in public spaces and can adversely affect the performance of pacemakers and implantable cardioverter defibrillators. The interaction between implantable devices and EAS systems is a serious problem that can be minimized through appropriate facility design. Careful facility design and employee education along with patient vigilance remain imperative in avoiding potentially life-threatening EAS system-implantable device interactions.


Assuntos
Desfibriladores Implantáveis , Campos Eletromagnéticos/efeitos adversos , Marca-Passo Artificial , Medidas de Segurança , Idoso , Eletrocardiografia , Segurança de Equipamentos , Feminino , Humanos , Masculino
6.
Circ Heart Fail ; 6(1): 118-26, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-23170010

RESUMO

BACKGROUND: Glucose 6-phosphate dehydrogenase (G6PD) is the most common deficient enzyme in the world. In failing hearts, G6PD is upregulated and generates reduced nicotinamide adenine dinucleotide phosphate (NADPH) that is used by the glutathione pathway to remove reactive oxygen species but also as a substrate by reactive oxygen species-generating enzymes. Therefore, G6PD deficiency might prevent heart failure by decreasing NADPH and reactive oxygen species production. METHODS AND RESULTS: This hypothesis was evaluated in a mouse model of human G6PD deficiency (G6PDX mice, ≈40% normal activity). Myocardial infarction with 3 months follow-up resulted in left ventricular dilation and dysfunction in both wild-type and G6PDX mice but significantly greater end diastolic volume and wall thinning in G6PDX mice. Similarly, pressure overload induced by transverse aortic constriction (TAC) for 6 weeks caused greater left ventricular dilation in G6PDX mice than wild-type mice. We further stressed transverse aortic constriction mice by feeding a high fructose diet to increase flux through G6PD and reactive oxygen species production and again observed worse left ventricular remodeling and a lower ejection fraction in G6PDX than wild-type mice. Tissue content of lipid peroxidation products was increased in G6PDX mice in response to infarction and aconitase activity was decreased with transverse aortic constriction, suggesting that G6PD deficiency increases myocardial oxidative stress and subsequent damage. CONCLUSIONS: Contrary to our hypothesis, G6PD deficiency increased redox stress in response to infarction or pressure overload. However, we found only a modest acceleration of left ventricular remodeling, suggesting that, in individuals with G6PD deficiency and concurrent hypertension or myocardial infarction, the risk for developing heart failure is higher but limited by compensatory mechanisms.


Assuntos
Deficiência de Glucosefosfato Desidrogenase/complicações , Glucosefosfato Desidrogenase/metabolismo , Insuficiência Cardíaca/etiologia , Miocárdio/enzimologia , Remodelação Ventricular , Animais , Modelos Animais de Doenças , Progressão da Doença , Deficiência de Glucosefosfato Desidrogenase/metabolismo , Insuficiência Cardíaca/metabolismo , Insuficiência Cardíaca/fisiopatologia , Peroxidação de Lipídeos , Masculino , Camundongos , Camundongos Endogâmicos C3H , Oxirredução , Espécies Reativas de Oxigênio/metabolismo
7.
J Cardiovasc Transl Res ; 6(6): 1000-10, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-24065618

RESUMO

Marine n-3 polyunsaturated fatty acids alter cardiac phospholipids and prevent cardiac pathology in rodents subjected to pressure overload. This approach has not been evaluated in humans or large animals with hypertension-induced pathological hypertrophy. We evaluated docosahexaenoic acid (DHA) in old female dogs with hypertension caused by 16 weeks of aldosterone infusion. Aldosterone-induced hypertension resulted in concentric left ventricular (LV) hypertrophy and impaired diastolic function in placebo-treated dogs. DHA supplementation increased DHA and depleted arachidonic acid in cardiac phospholipids, but did not improve LV parameters compared to placebo. Surprisingly, DHA significantly increased serum aldosterone concentration and blood pressure compared to placebo. Cardiac mitochondrial yield was decreased in placebo-treated hypertensive dogs compared to normal animals, which was prevented by DHA. Extensive analysis of mitochondrial function found no differences between DHA and placebo groups. In conclusion, DHA did not favorably impact mitochondrial or LV function in aldosterone hypertensive dogs.


Assuntos
Pressão Sanguínea/efeitos dos fármacos , Ácidos Docosa-Hexaenoicos/efeitos adversos , Hipertensão/induzido quimicamente , Hipertrofia Ventricular Esquerda/induzido quimicamente , Função Ventricular Esquerda/efeitos dos fármacos , Aldosterona , Animais , Ácido Araquidônico/metabolismo , Modelos Animais de Doenças , Cães , Feminino , Fibrose , Hipertensão/sangue , Hipertensão/fisiopatologia , Hipertrofia Ventricular Esquerda/sangue , Hipertrofia Ventricular Esquerda/patologia , Hipertrofia Ventricular Esquerda/fisiopatologia , Mitocôndrias Cardíacas/efeitos dos fármacos , Mitocôndrias Cardíacas/metabolismo , Miocárdio/metabolismo , Miocárdio/patologia , Fosfolipídeos/metabolismo , Fatores de Tempo
8.
Sci Total Environ ; 435-436: 337-44, 2012 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-22863809

RESUMO

Loss of dissolved organic matter (DOM) from soils can have negative effects on soil fertility and water quality. It is known that sodicity increases DOM solubility, but the interactive effect of sodicity and salinity on DOM sorption and how this is affected by soil texture is not clear. We investigated the effect of salinity and sodicity on DOM sorption in soils with different clay contents. Four salt solutions with different EC and SAR were prepared using combinations of 1M NaCl and 1M CaCl(2) stock solutions. The soils differing in texture (4, 13, 24 and 40% clay, termed S-4, S-13, S-24 and S-40) were repeatedly leached with these solutions until the desired combination of EC and SAR (EC(1:5) 1 and 5dSm(-1) in combination with SAR <3 or >20) was reached. The sorption of DOC (derived from mature wheat straw) was more strongly affected by SAR than by EC. High SAR (>20) at EC1 significantly decreased sorption in all soils. However, at EC5, high SAR did not significantly reduce DOC sorption most likely because of the high electrolyte concentration of the soil solution. DOC sorption was greatest in S-24 (which had the highest CEC) at all concentrations of DOC added whereas DOC sorption did not differ greatly between S-40 and S-4 or S-13 (which had higher concentrations of Fe/Al than S-40). DOC sorption in salt-affected soil is more strongly controlled by CEC and Fe/Al concentration than by clay concentration per se except in sodic soils where DOC sorption is low due to the high sodium saturation of the exchange complex.


Assuntos
Compostos Orgânicos/química , Salinidade , Solo/química , Adsorção , Alumínio/química , Silicatos de Alumínio/química , Cloreto de Cálcio/química , Argila , Ferro/química
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