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1.
Eur J Clin Microbiol Infect Dis ; 35(3): 443-6, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26740325

RESUMO

The purpose of this investigation was to evaluate the patient characteristics, clinical manifestations, microbiology, and modes of treatment of a large cohort of women with acute Bartholin's abscess, from a single medical center. A retrospective study was undertaken of all women diagnosed with acute Bartholin's gland abscess who were admitted to the gynecology department in a university-affiliated tertiary hospital in central Israel from January 2004 to December 2013. A total of 267 women were included in the study. The mean age at diagnosis was 33.5 ± 12.1 years and the mean hospitalization period was 1.4 ± 0.9 days. Pain presented in 152 (56.9 %), swelling in 81 (30.3 %), and fever in 34 (12.7 %). Leukocytosis was detected in 149 (55.8 %). The three main treatment modalities were: antibiotics (75.7 %), abscess drainage (19.1 %), and marsupialization (80.9 %). Bacterial infections were detected in 154 (57.7 %) cultures, Escherichia coli presented in 59 (22.1 %), and Streptococcus species in 27 (10.1 %). The clinical and patient characteristics were similar between women with bacterial and sterile Bartholin's abscesses, though leukocytosis was more prevalent among women with bacterial infections. E. coli was the single most frequent pathogen in cultures of acute Bartholin's abscess. Respiratory tract-associated organisms were also common. This study indicates the polymicrobial spectrum of acute Bartholin's abscess.


Assuntos
Abscesso/diagnóstico , Abscesso/microbiologia , Glândulas Vestibulares Maiores/microbiologia , Glândulas Vestibulares Maiores/patologia , Abscesso/cirurgia , Doença Aguda , Adulto , Infecções Bacterianas/diagnóstico , Infecções Bacterianas/microbiologia , Infecções Bacterianas/cirurgia , Estudos de Coortes , Terapia Combinada , Feminino , Humanos , Pessoa de Meia-Idade , Recidiva , Estudos Retrospectivos , Fatores de Risco , Resultado do Tratamento , Adulto Jovem
2.
Science ; 205(4409): 917-9, 1979 Aug 31.
Artigo em Inglês | MEDLINE | ID: mdl-224455

RESUMO

The Na+,k+-adenosine triphosphatase-inhibiting activity of digitalis genins and their analogs is a function of side-group carbonyl (C = O) oxygen position. For each 2.2 angstroms that this oxygen is displaced from its position in digitoxigenin, activity drops by one order of magnitude. This quantitative relation resolves previously proposed models which have attempted to describe the molecular basis of genin activity. A multidisciplinary (crystallographic, conformational energy, synthetic, biological) approach to structure-activity relations is described.


Assuntos
Glicosídeos Digitálicos/farmacologia , ATPase Trocadora de Sódio-Potássio/antagonistas & inibidores , Animais , Encéfalo/enzimologia , Conformação Molecular , Ratos , Relação Estrutura-Atividade
3.
Acta Radiol ; 49(4): 409-14, 2008 May.
Artigo em Inglês | MEDLINE | ID: mdl-18415784

RESUMO

BACKGROUND: Previous studies that have attempted to evaluate the effectiveness of an iso-osmolar contrast medium (IOCM) iodixanol compared to a low-osmolar contrast medium (LOCM) for contrast procedures show variable results. PURPOSE: To evaluate the nephrotoxicity of the IOCM iodixanol compared to the LOCM iohexol. MATERIAL AND METHODS: We performed a retrospective cohort study from April 2004 to March 2006. All contrast procedures with a pre- and post-exposure creatinine value were evaluated for inclusion. Contrast nephropathy (CN) was defined as post-exposure creatinine elevation of > or = 25% or > 0.5 mg/dl within 7 days of contrast exposure. Cases of iodixanol exposure were matched to control cases of iohexol exposure (1:1) based on age, sex, presence of diabetes, pre-exposure creatinine value, and type of imaging study performed. We matched 397 cases of iodixanol (IOCM) exposure to 397 cases of iohexol (LOCM) exposure. Cases of iodixanol which could not be matched to controls were not included in the analysis. RESULTS: After adjustment for prior creatinine, medications, contrast iodine load, prior exposure to contrast material, heart failure, and hypertension, use of iodixanol did not significantly alter rates of CN compared to iohexol (OR 0.92, 95% CI 0.57-1.46; P = 0.71) or mortality (RR 0.79, 95% CI 0.59-1.06; P = 0.12). CONCLUSION: The use of the IOCM iodixanol was not associated with statistically significant protection against contrast nephropathy or all-cause mortality compared to a matched cohort of patients receiving the LOCM iohexol.


Assuntos
Iohexol , Ácidos Tri-Iodobenzoicos , Idoso , Angiografia , Estudos de Casos e Controles , Distribuição de Qui-Quadrado , Meios de Contraste/efeitos adversos , Creatinina/urina , Feminino , Taxa de Filtração Glomerular , Humanos , Iohexol/efeitos adversos , Nefropatias/induzido quimicamente , Nefropatias/terapia , Modelos Logísticos , Masculino , Modelos de Riscos Proporcionais , Diálise Renal , Estudos Retrospectivos , Tomografia Computadorizada por Raios X , Ácidos Tri-Iodobenzoicos/efeitos adversos
4.
J Clin Invest ; 92(2): 993-1003, 1993 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-8349829

RESUMO

Transmurally localized 31P-nuclear magnetic resonance spectroscopy (NMR) was used to study the effect of severe pressure overload left ventricular hypertrophy (LVH) on myocardial high energy phosphate content. Studies were performed on 8 normal dogs and 12 dogs with severe left ventricular hypertrophy produced by banding the ascending aorta at 8 wk of age. Spatially localized 31P-NMR spectroscopy provided measurements of the transmural distribution of myocardial ATP, phosphocreatine (CP), and inorganic phosphate (Pi); spectra were calibrated from measurements of ATP content in myocardial biopsies using HPLC. Blood flow was measured with microspheres. In hypertrophied hearts during basal conditions, ATP was decreased by 42%, CP by 58%, and the CP/ATP ratio by 32% in comparison with normal. Increasing myocardial blood flow with adenosine did not correct these abnormalities, indicating that they were not the result of persistent hypoperfusion. Atrial pacing at 200 and 240 beats per min caused no change in high energy phosphate content in normal hearts but resulted in further CP depletion with Pi accumulation in the inner left ventricular layers of the hypertrophied hearts. These changes were correlated with redistribution of blood flow away from the subendocardium in LVH hearts. These findings demonstrate that high energy phosphate levels and the CP/ATP ratio are significantly decreased in severe LVH. These abnormalities are proportional to the degree of hypertrophy but are not the result of persistent abnormalities of myocardial perfusion. In contrast, depletion of CP and accumulation of Pi during tachycardia in LVH are closely related to the pacing-induced perfusion abnormalities and likely reflect subendocardial ischemia.


Assuntos
Metabolismo Energético , Coração/fisiopatologia , Hipertrofia Ventricular Esquerda/fisiopatologia , Miocárdio/metabolismo , Adenosina/metabolismo , Trifosfato de Adenosina/metabolismo , Animais , Pressão Sanguínea , Peso Corporal , Creatinina/metabolismo , Cães , Coração/fisiologia , Frequência Cardíaca , Hipertrofia Ventricular Esquerda/metabolismo , Espectroscopia de Ressonância Magnética/métodos , Tamanho do Órgão , Fosfatos/metabolismo , Fosfocreatina/metabolismo , Fósforo , Valores de Referência
5.
J Am Coll Cardiol ; 36(1): 282-7, 2000 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-10898447

RESUMO

OBJECTIVES: This study was conducted to test hypotheses stating that: 1) altered signaling for mitochondrial membrane proteins occurs during postinfarction remodeling, and 2) successful myocardial adaptation relates to promotion of specific mitochondrial membrane components. BACKGROUND: Abnormalities in high-energy phosphate content and limitations in adenosine 5'-triphosphate (ATP) synthesis rate occur during the transition to contractile failure from compensatory remodeling after left ventricular infarction. The adenine nucleotide translocator (ANT) and F1-ATPase respectively regulate mitochondrial adenosine 5'-diphosphate (ADP)/ATP exchange and ADP-phosphorylation, which are key components of high-energy phosphate metabolism. METHODS: Steady-state mRNA and protein expression for ANT isoform1 and the beta subunit of the F1-ATPase (betaF1) were analyzed in myocardium remote from the infarction zone eight weeks after left circumflex coronary artery ligation in pigs, demonstrating either successful left ventricular remodeling (LVR, n = 8) or congestive heart failure (CHF, n = 4) as determined by clinical and contractile performance parameters. RESULTS: Substantial reductions in steady-state mRNA expression for ANT1 and betaF1 relative to normal (n = 8) occur in CHF, p < 0.01, but not in LVR. Relative expression for both proteins coordinated with their respective steady-state mRNA levels; CHF at 40% normal, p < 0.05 for ANT and 70% normal for betaF1, p < 0.05. CONCLUSIONS: Maintained signaling for major mitochondrial membrane proteins occurs in association with successful remodeling and adaptation after infarction. Reduced expression of these proteins relates to limited ATP synthesis capacity and high energy phosphate kinetic abnormalities previously demonstrated in CHF. These findings imply that mitochondrial processes participate in myocardial remodeling after infarction.


Assuntos
Insuficiência Cardíaca/genética , Mitocôndrias Cardíacas/metabolismo , Translocases Mitocondriais de ADP e ATP/genética , ATPases Translocadoras de Prótons/genética , Transdução de Sinais , Remodelação Ventricular , Animais , Biomarcadores , Northern Blotting , Western Blotting , Progressão da Doença , Expressão Gênica , Insuficiência Cardíaca/metabolismo , Insuficiência Cardíaca/fisiopatologia , Translocases Mitocondriais de ADP e ATP/metabolismo , Contração Miocárdica , ATPases Translocadoras de Prótons/metabolismo , RNA Mensageiro/biossíntese , Suínos
6.
Arch Intern Med ; 141(2): 164-6, 1981 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-7458511

RESUMO

Serum creatine kinase MB isoenzyme (CK-MB) activity was determined in 46 male long-term hemodialysis patients without evidence of myocardial infarction. Thirteen (28.3%) showed mild elevations. The abnormality persisted in seven of eight patients on repeated measurement at three- to eight-month intervals. There was a significant correlation between serum CK-MB and CK-MN activity, and the activity of both enzymes rose after intramuscular injection. The reason for the abnormality is not known. It is possible that skeletal muscle is the source of elevated enzyme activity. Caution should be exercised in the interpretation of serum CK-MB activity in the diagnosis of acute myocardial infarction in this patient population.


Assuntos
Creatina Quinase/sangue , Infarto do Miocárdio/enzimologia , Diálise Renal , Adulto , Idoso , Humanos , Injeções Intramusculares , Isoenzimas , Masculino , Pessoa de Meia-Idade , Músculos/enzimologia , Infarto do Miocárdio/diagnóstico , Nandrolona/uso terapêutico , Pericardite/tratamento farmacológico , Pericardite/enzimologia
7.
Cardiovasc Res ; 42(3): 616-26, 1999 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-10533601

RESUMO

BACKGROUND: High cardiac workloads produced by catecholamine infusion result in loss of myocardial phosphocreatine (PCr) and accumulation of inorganic phosphate (Pi) which are more prominent in heart with left ventricular hypertrophy (LVH) than in normal hearts. Since ischemia can cause changes in phosphorylated compounds similar to those during catecholamine stimulation, this study tested the hypothesis that the exaggerated depletion of PCr and accumulation of Pi during high workloads in LVH is the result of impaired myocyte oxygenation. METHODS AND RESULTS: 31P- and 1H-NMR spectroscopy were used to determine myocardial high energy phosphate levels and myoglobin desaturation, respectively, in eight normal dogs and nine dogs with LVH produced by ascending aortic banding. The mean LV weight/body weight ratio was approximately twice normal in the LVH group. Infusion of dobutamine (15 and 30 micrograms/kg/min), and dobutamine + dopamine (each 20 micrograms/kg/min) caused progressive similar increases in the heart rate x systolic LV pressure product to a maximum of 57.4 +/- 3.3 x 10(3) in normal and 63.9 +/- 2.7 x 10(3) in LVH animals, while myocardial oxygen consumption increased from 0.09 +/- 0.01 to 0.24 +/- 0.04 in normals and from 0.10 +/- 0.02 to 0.25 +/- 0.03 ml/min/g in LVH. PCr/ATP ratios during basal conditions were lower in LVH hearts (1.73 +/- 0.10, 1.61 +/- 0.09 and 1.51 +/- 0.09 in subepicardium, midwall and subendocardium, respectively) as compared with normals (2.24 +/- 0.09, 2.01 +/- 0.08 and 1.89 +/- 0.07; each p < 0.01 normal vs. LVH). Catecholamine infusions caused dose-related decreases in PCr/ATP and appearance of Pi which was more marked in LVH than in normal hearts. 1H-NMR spectroscopy did not detect deoxymyoglobin in either normal or LVH hearts even during the highest workloads. In contrast, occlusion of the anterior descending coronary artery resulted in a large deoxymyoglobin signal. CONCLUSIONS: Increases of cardiac work produced by catecholamine stimulation resulted in greater decreases of PCr and greater increases of Pi in hypertrophied than in normal hearts. These abnormalities were not the result of inadequate intracellular oxygen availability and consequently cannot be ascribed to demand ischemia.


Assuntos
Cardiotônicos , Dobutamina , Hipertrofia Ventricular Esquerda/metabolismo , Miocárdio/metabolismo , Consumo de Oxigênio , Trifosfato de Adenosina/metabolismo , Animais , Circulação Coronária , Cães , Hipertrofia Ventricular Esquerda/fisiopatologia , Espectroscopia de Ressonância Magnética , Microesferas , Mitocôndrias Cardíacas/metabolismo , Fosfocreatina/metabolismo
8.
Int J Surg ; 20: 75-9, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-26079498

RESUMO

INTRODUCTION: We investigated parameters associated with recurrence after partial (Le Fort) colpocleisis surgery for severe pelvic organ prolapse (POP) in elderly women. METHODS: A retrospective cohort study included all women who underwent partial colpocleisis in a single tertiary center from February 2007 through July 2013 for stage 3 or 4 triple compartment prolapse. Inclusion criteria were age over 60, sexually inactive, medical comorbidities, increased risk for comprehensive reconstructive pelvic surgery, and refusal or failure to use a pessary as a conservative non-surgical treatment. Exclusion criteria were post-menopausal bleeding, pelvic malignancy, and the desire to preserve coital function. RESULTS: The study group included 47 women of mean age 77.3 ± 8.2 (range 61-91 years). All had medical comorbidities. Fourteen patients (29.8%) had undergone previous hysterectomy. All patients underwent partial colpocleisis and perineorrhaphy. Seven women (14.9%) underwent mid-urethral sling for urinary incontinence. Mean follow-up was 14.8 ± 10.3 months (range, 2-37 months) and mean hospitalization, 3.5 ± 1.5 days (range, 2-9 days). There were no intraoperative complications. Postoperative complications comprised lower urinary tract infection (n = 2). Objective cure (according to vaginal examination) was 80.9% (38/47), and subjective (according to symptoms), 91.5% (43/47). No patient regretted the loss of sexual function. The main reasons for prolapse recurrence were statistically significant longer post-operative vaginal length and wider genital hiatus. CONCLUSIONS: Objective and subjective cure rates of Le Fort colpocleisis for the treatment of severe POP were high with low morbidity. Parameters associated with prolapse recurrence were longer postoperative vaginal length and wider genital hiatus.


Assuntos
Colpotomia/efeitos adversos , Prolapso de Órgão Pélvico/cirurgia , Idoso , Idoso de 80 Anos ou mais , Colpotomia/métodos , Feminino , Humanos , Histerectomia , Pessoa de Meia-Idade , Prolapso de Órgão Pélvico/complicações , Prolapso de Órgão Pélvico/patologia , Complicações Pós-Operatórias/etiologia , Recidiva , Estudos Retrospectivos , Fatores de Risco , Incontinência Urinária/etiologia , Incontinência Urinária/cirurgia , Vagina/patologia , Vagina/cirurgia
9.
Endocrinology ; 112(4): 1358-62, 1983 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-6299691

RESUMO

Acetylcholine (ACh; 5 X 10(-4) M), like norepinephrine (NE; 6 X 10(-6) M), as shown previously, stimulated iodide organification by mouse thyroids in vitro, while at the same time it inhibited TSH- or (Bu)2cAMP-induced T4 release. However, thyroid cAMP was not changed by ACh, suggesting that ACh, like NE, exerted its effects at a step beyond cAMP production. Also, while ACh increased cGMP concentrations, (Bu)2cGMP and 8-bromo-cGMP were not effective on thyroid function in this system. Neurotransmitters, then, presumably do not exert their action through cyclic nucleotide stimulation ACh-induced stimulation of organification and inhibition of release was reversed by 10(-5) M atropine (ATR) but not by 10(-5) M d-tubocurarine, indicating that muscarinic receptors were involved. ATR also reversed inhibition of T4 release induced by NE, suggesting that the presynaptic cholinergic pathway may be responsible for stimulation of postsynaptic cholinergic and adrenergic neurotransmitters in the thyroid gland.


Assuntos
Acetilcolina/farmacologia , Norepinefrina/farmacologia , Glândula Tireoide/metabolismo , Animais , Atropina/farmacologia , Bucladesina/farmacologia , AMP Cíclico/metabolismo , GMP Cíclico/metabolismo , Feminino , Humanos , Iodetos/metabolismo , Camundongos , Glândula Tireoide/efeitos dos fármacos , Tireotropina/antagonistas & inibidores , Tiroxina/metabolismo
10.
Endocrinology ; 108(5): 1987-8, 1981 May.
Artigo em Inglês | MEDLINE | ID: mdl-6260472

RESUMO

Excised mouse thyroids incubated in Ca++-free medium were stimulated to release increased amounts of stable thyroxine. This stimulation of thyroxine release by incubated thyroid tissue was not additive with TSH or (Bu)2cAMP. It was reversed by norepinephrine through an alpha adrenergic receptor, similar to TSH or (Bu)2cAMP stimulation. Depletion of Ca++ did not result, however, in an increase in the concentration of cAMP in incubated thyroid glands, suggesting that its locus of action was subsequent to TSH stimulation or cAMP production.


Assuntos
Cálcio/farmacologia , Glândula Tireoide/metabolismo , Tiroxina/metabolismo , Animais , Bucladesina/farmacologia , Técnicas In Vitro , Camundongos , Norepinefrina/farmacologia , Receptores Adrenérgicos alfa/fisiologia , Glândula Tireoide/efeitos dos fármacos , Tireotropina/farmacologia
11.
Endocrinology ; 109(3): 930-4, 1981 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-6167436

RESUMO

Norepinephrine (NE), which has previously been shown to inhibit TSH-induced T4 release by mouse thyroids in vitro, was found to stimulate iodide organification. The concentration of NE (6 X 10(-7) M) necessary to stimulate organification of iodide was 10 times less than the concentration (6 X 10(-6) M) required for inhibition of TSH-induced T4 release. Both actions of NE were exerted through an alpha-adrenergic receptor, since they were inhibited by phentolamine but not by l-propranolol. One milliunit of TSH maximally stimulated T4 release only, but larger amounts (100 mU) also stimulated organification. TSH stimulation of T4 release and organification was not affected by adrenergic antagonists and therefore was not mediated by adrenergic receptors. N6, O2-Dibutyryl cAMP and isobutylmethylxanthine, like TSH, stimulated T4 release. Their actions were inhibited by NE. However, both compounds, unlike TSH, failed to enhance organification in mouse thyroids. The effects of TSH and NE on the cAMP content of incubated mouse thyroids were also studied. TSH induced a prolonged increase in thyroidal cAMP during the 90-min incubation; this increase was unaffected by alpha- or beta-adrenergic antagonists. In contrast, NE (6 X 10(-5) M) produced a transient but significant increase in cAMP only within the first 5 min. Unlike the action of NE on organification, this short term stimulatory effect on cAMP production was mediated by a beta-adrenergic receptor, since it was blocked by l-propranolol but not by phentolamine. The following conclusions were reached: 1) stimulation of iodide organification and thyroid hormone release involves different sensitivity thresholds for TSH and NE; 2) TSH stimulation of iodide organification, hormone release, and cAMP formation is not exerted through adrenergic receptors; 3) NE stimulates organification and inhibits TSH-stimulated T4 release through alpha-adrenergic receptors, but stimulates cAMP production through beta-receptors; and 4) cAMP may not be the mediator of all TSH actions on the thyroid.


Assuntos
Iodetos/metabolismo , Norepinefrina/farmacologia , Glândula Tireoide/fisiologia , Tireotropina/farmacologia , Tiroxina/metabolismo , 1-Metil-3-Isobutilxantina/farmacologia , Animais , Bucladesina/farmacologia , AMP Cíclico/metabolismo , Feminino , Masculino , Camundongos , Fentolamina/farmacologia , Ratos , Glândula Tireoide/efeitos dos fármacos
12.
Endocrinology ; 101(1): 284-91, 1977 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-193681

RESUMO

Thyrotropin (TSH), 1 MU/ml and N6, O2'-dibutyryl adenosine 3',5-cyclic monophosphoric acid (dbcAMP) greatly enhanced the release of thyroxine (T4) and triiodothyronine (T3) from mouse thyroids incubated in vitro. L-Epinephrine (E) and L-norepinephrine (NE) strongly inhibited the TSH and dbcAMP-stimulated release of thyroid hormones; L-isoproterenol (IPNE) exerted a relatively weak inhibition. The inhibition by catecholamines was prevented by the alpha-adrenergic blocker, phentolamine; L-propranolol, a beta-adrenergic blocker, had no effect on the inhibition. The TSH-induced release of thyroid hormones was not affected by adrenergic blockers. Epinephrine did not affect the increase in thyroidal cAMP content induced by TSH. These results indicate that catecholamines act by way of an alpha-adrenergic receptor to suppress TSH-stimulated release of thyroid hormones at a point beyond cAMP formation.


Assuntos
Bucladesina/farmacologia , Catecolaminas/farmacologia , Glândula Tireoide/metabolismo , Tireotropina/farmacologia , Tiroxina/metabolismo , Tri-Iodotironina/metabolismo , Animais , AMP Cíclico/farmacologia , Epinefrina/farmacologia , Técnicas In Vitro , Isoproterenol/farmacologia , Masculino , Camundongos , Norepinefrina/farmacologia , Fentolamina/farmacologia , Propranolol/farmacologia , Receptores Adrenérgicos alfa/fisiologia , Glândula Tireoide/efeitos dos fármacos , Fatores de Tempo
13.
J Clin Endocrinol Metab ; 56(5): 925-9, 1983 May.
Artigo em Inglês | MEDLINE | ID: mdl-6300177

RESUMO

Ouabain binding and electrolyte concentrations of erythrocytes, and Na+, K+-ATPase activity of red cell ghosts were measured in normal and obese subjects, ranging from 88-257% of their ideal body weight. All three independent measurements were virtually the same in obese and nonobese groups, and no correlations were found between these three variables and the percentage of ideal body weight. These results differ from previous reports of either increased or decreased sodium pump function and suggest that Na+, K+-ATPase does not directly influence human obesity.


Assuntos
Eritrócitos/metabolismo , Canais Iônicos/metabolismo , Obesidade/sangue , Sódio/sangue , Adulto , Idoso , Membrana Eritrocítica/enzimologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Ouabaína/sangue , Potássio/sangue , ATPase Trocadora de Sódio-Potássio/sangue
14.
FEBS Lett ; 206(2): 257-61, 1986 Oct 06.
Artigo em Inglês | MEDLINE | ID: mdl-3530811

RESUMO

The mechanism by which mitochondrial respiration is coupled to ATP consumption in intact tissues is unclear. We determined the relationship between high-energy phosphate levels and oxygen consumption rate in rat hearts operating over a range of workloads and perfused with different substrates. With pyruvate +glucose perfusion, ADP levels were in general very low, and varied with MVO2 yielding an apparent Km of 25 +/- 5 microM, suggesting regulation of oxidative phosphorylation through availability of ADP. In contrast, with glucose perfusion in the presence or absence of insulin, ADP levels, ADP/ATP ratio or the phosphate potential were relatively constant over the workload range examined and generally not correlated with alterations in MVO2; it is suggested that under these conditions, carbon substrate delivery to the mitochondria may control mitochondrial respiration. The common feature of both of the suggested regulatory mechanisms is substrate limitation which, however, is exercised at different metabolic points depending on the carbon substrate available to the myocardium.


Assuntos
Miocárdio/metabolismo , Consumo de Oxigênio , Fosfatos/metabolismo , Difosfato de Adenosina/metabolismo , Trifosfato de Adenosina/metabolismo , Animais , Glucose/metabolismo , Insulina/farmacologia , Cinética , Espectroscopia de Ressonância Magnética , Mitocôndrias/metabolismo , Consumo de Oxigênio/efeitos dos fármacos , Piruvatos/metabolismo , Ácido Pirúvico , Ratos
15.
FEBS Lett ; 167(1): 73-8, 1984 Feb 13.
Artigo em Inglês | MEDLINE | ID: mdl-6698205

RESUMO

High resolution 1H NMR spectra of perfused rat hearts have been obtained under normoxic, ischemic and hypoxic conditions. Several myocardial metabolites including taurine, carnitine, lactate and tissue glycerides are detected in the 1H NMR spectra. Changes in oxygen availability induce perturbations in the levels of some metabolites, in particular, lactate. Experiments with fasted rats and with substrate-free perfusion suggest that the glycerides detected in 1H spectra are metabolically mobilizable but have a slow rate of turnover. These results demonstrate that utility of 1H NMR in monitoring myocardial metabolism.


Assuntos
Miocárdio/metabolismo , Animais , Jejum , Hipóxia/metabolismo , Espectroscopia de Ressonância Magnética , Consumo de Oxigênio , Perfusão , Ratos , Ratos Endogâmicos
16.
FEBS Lett ; 198(1): 159-63, 1986 Mar 17.
Artigo em Inglês | MEDLINE | ID: mdl-2869973

RESUMO

Using 31P NMR and the saturation-transfer method, the unidirectional rate of ATP synthesis was measured in isolated, Langendorff-perfused, isovolumic rat hearts operating at a rate pressure product of 25.6 +/- 2.5 (SE) X 10(3) mmHg X min-1 and consuming O2 at a rate of 35 +/- 2 mumol O2 X min-1 X (g dry wt)-1, at 37 degrees C. This rate was 7.2 +/- 0.9 mumol X s-1 X (g dry wt)-1 and was related to the rate of oxygen atom consumption by a ratio of 6.3 +/- 0.9. These data show that in the intact heart the unidirectional rate of ATP synthesis exceeds the net rate of ATP synthesis and consumption by approximately a factor of 2.


Assuntos
Trifosfato de Adenosina/biossíntese , Miocárdio/metabolismo , Animais , Técnicas In Vitro , Espectroscopia de Ressonância Magnética , Masculino , Consumo de Oxigênio , Perfusão , Fosfatos/metabolismo , ATPases Translocadoras de Prótons/análise , Ratos
17.
Am J Clin Nutr ; 40(2): 339-45, 1984 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-6147085

RESUMO

Because it has been suggested that decreased activity at the erythrocyte sodium pump might be the cause of age-related decreases in basal oxygen consumption, we have examined age-associated changes in Na+,K+-ATPase activity in red cell membranes. The initial portion of this study was directed toward elucidating possible methodological pitfalls in membrane preparation which might account for some of the variable results reported in prior erythrocyte Na+,K+-ATPase studies. We found that two of four red cell membrane fractions have substantial Mg2+-ATPase activity and contribute a significant portion of total membrane protein. As these two fractions contain little Na+,K+-ATPase activity their contamination of the other two fractions could cause significant variation in measured Na+,K+-ATPase activity. Additionally, we found that meal feeding raised Na+,K+-ATPase activity necessitating that measurements be made in the fasting state. With these methodological variables controlled, we found only a 10.8% coefficient of variation between fasting samples obtained on separate days in eight subjects. Using this methodology, we observed no correlation of Na+,K+-ATPase specific activity with age in males, and only a weak correlation in females who showed decreasing Na+,K+-ATPase specific activity occurring with advancing age. These observations suggest that changes in erythrocyte Na+,K+-ATPase activity do not cause the age-related fall in basal oxygen consumption.


Assuntos
Envelhecimento , Eritrócitos/enzimologia , Alimentos , ATPase Trocadora de Sódio-Potássio/sangue , Adenosina Trifosfatases/sangue , Adolescente , Adulto , Idoso , ATPase de Ca(2+) e Mg(2+) , Membrana Eritrocítica/enzimologia , Feminino , Humanos , Canais Iônicos , Masculino , Pessoa de Meia-Idade , Consumo de Oxigênio , Fatores Sexuais , Sódio/sangue
18.
J Med Chem ; 19(11): 1330-3, 1976 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-137317

RESUMO

A 17beta-unsaturated aldehyde analogue [3beta,14beta-dihydroxy-5beta-pregn-17beta-trans-20-en-22-al (7)] of the cardenolides was synthesized and studied. In earlier studies by Rappoport, unsaturated aldehydes were found to be highly active electrophiles, more active, for example, than unsaturated nitriles or methyl esters. The synthesis followed in part a scheme previously reported by Thomas for the syntheses of the 17beta-unsaturated nitrile 9 and the 17beta-unsaturated methyl and ethyl esters 8 and 10. Both 9 and 8 are more Na+,K+-ATPase inhibiting and slightly less inotropic than digitoxigenin (1b). However, the unsaturated aldehyde 7 was less Na+,K+-ATPase inhibiting (I50 - 9.9 +/- 0.7 X 10(-7) M) and less inotropic (100% increase in contractile force at 8.5 +/- 1.0 X 10(-6) M) than 1b (I50 - 4.6 +/- 1.6 X 10(-7) M; 100% increase at 3.0 +/- 1.0 X 10(-7) M).


Assuntos
Cardenolídeos/síntese química , Adenosina Trifosfatases/antagonistas & inibidores , Animais , Encéfalo/enzimologia , Cardenolídeos/farmacologia , Cobaias , Técnicas In Vitro , Contração Miocárdica/efeitos dos fármacos , Ratos , Relação Estrutura-Atividade
19.
J Med Chem ; 29(10): 1945-52, 1986 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-3020248

RESUMO

Digitoxigenin alpha-L-, beta-L-, alpha-D-, and beta-D-glucosides; alpha-L-, beta-L-, alpha-D-, and beta-D-mannosides; and alpha-L- and beta-L-rhamnosides were stereoselectively synthesized from the corresponding sugar tetrabenzyl trichloroacetimidates. The Na+,K+-ATPase receptor inhibitory activities of these glycosides (as a measure of receptor binding) were compared with those of digitoxigenin, digitoxigenin 6'-hydroxy-beta-D-digitoxoside, digitoxigenin beta-D-galactoside, and digitoxigenin beta-D-digitoxoside. The observed activities reveal that a given sugar substituent may have a role in binding of some glycoside stereoisomers, but not others. With alpha-L- and possibly beta-L-rhamnosides, the 5'-CH3 and 4'-OH appear to have a predominant role in binding to the Na+,K+-ATPase receptor. Addition of a 6'-OH to form the corresponding mannosides dramatically disrupts the effect of both the 5'-CH3 and 4'-OH in prompting receptor binding of the alpha-L isomer. However, with the beta-L isomer, some influence of 4'-OH, 3'-OH, and 2'-OH binding remains. With beta-D-glycosides, binding via the "5'-CH3 site" appears to be of little importance and addition of a 6'-OH diminishes activity only slightly. With these beta-D-glycosides, an equatorial 4'-OH, axial 3'-OH, and equatorial 2'-OH groups appear to contribute to binding.


Assuntos
Glicosídeos Cardíacos/síntese química , Glicosídeos Cardíacos/farmacologia , Conformação Molecular , ATPase Trocadora de Sódio-Potássio/antagonistas & inibidores , Relação Estrutura-Atividade
20.
J Med Chem ; 22(5): 529-33, 1979 May.
Artigo em Inglês | MEDLINE | ID: mdl-222907

RESUMO

(20R)-20,22-Dihydrodigitoxigenin (3a) and (20S)-20,22-dihydrodigitoxigenin (3b) were isolated from (20R,S)-20,22-dihydrodigitoxigenin (3) by three fractional crystallizations each from ethyl acetate. The two diastereomers have distinct NMR spectra and similar (Na+,K+)ATPase inhibitory activities (I50 = 1.1-1.4 X 10(-5) M)--about 1/100 as active as digitoxigenin (1). Their activity compared with other cardenolide analogues suggests a passive geometric role for the 20(22) double bond in eliciting (Na+,K+)ATPase inhibition, keeping the lactone carbonyl in the proper orientation. (20S)-3 beta,14 beta-Dihydroxy-22-methylene-5 beta,14 beta-cardanolide (7a) was then synthesized from 3a, and (20R)-3 beta,14 beta-dihydroxy-22-methylene-5 beta,14 beta-cardanolide (7b) from 3b. They were found to be equivalently active in inhibiting (Na+,K+)ATPase, with I50 values of 7.0 x 10(-5) M. Although it has been usually believed that the 14 beta-hydroxyl of cardenolides increases binding to the receptor, 2b (the 14-ene derivative of 7b) was more than twice as active (I50 = 3.0 X 10(-5)) than either 7a or 7b.


Assuntos
Cardanolídeos/farmacologia , Animais , Encéfalo/enzimologia , Cardanolídeos/síntese química , Cardenolídeos/farmacologia , Digitoxigenina/análogos & derivados , Digitoxigenina/síntese química , Digitoxigenina/farmacologia , Técnicas In Vitro , Espectroscopia de Ressonância Magnética , Conformação Molecular , Ratos , ATPase Trocadora de Sódio-Potássio/antagonistas & inibidores , Estereoisomerismo , Relação Estrutura-Atividade
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