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1.
Biochim Biophys Acta ; 1359(2): 153-64, 1997 Nov 27.
Artigo em Inglês | MEDLINE | ID: mdl-9409812

RESUMO

Endothelin is a potent vasoactive peptide whose concentration increases in a number of pathophysiological states. In the intact animal, the liver is known to sequester approximately 12% of an injected bolus of [125I]endothelin-1 ([125I]ET-1). Endothelial cells (ECs) isolated from rat liver were maintained in culture in order to examine their role in ET sequestration. LECs were shown to express predominantly ET(B) receptors both by association assays and by Northern blot analysis. In these cells the reaction between [125I]ET-1 and its receptor was essentially irreversible. Ligand binding experiments performed at 4 degrees C showed that LECs in early culture (approximately 3 h) had 4.3 +/- 0.8 fmol of ET receptors per 10(6) cells; this number fell progressively to < or = 1 fmol/10(6) cells during 24 h of culture. The decrease in receptor numbers could be blocked by maintaining the cells at 4 degrees C. Northern blot analysis showed that relative to freshly isolated cells, mRNA for the ET(B) receptor decreased 4-fold in early culture, and recovered somewhat at 24 h. At 37 degrees C [125I]ET-1 bound by the cells was rapidly internalized, with concomitant down-regulation of ET receptors. Recovery of down-regulated ET receptors was sensitive to cycloheximide, making short-term receptor recycling unlikely. Metabolism of [125I]ET-1 was low at short (< 4 h) exposure times, and at 24 h showed a concentration dependence similar to that of ligand association, suggesting that ET-1 metabolism primarily was intracellular. ET stimulation of Kupffer cells and other hepatic cell types is known to activate phosphoinositide signaling, but no such activation was seen in LECs. Moreover, ET did not appear to stimulate protein tyrosine kinase activity in LECs. While hepatic LECs may lack some of the ET-dependent responses seen in other cell types, they likely contribute substantially to the liver's previously reported ability to sequester systemically administered ET.


Assuntos
Endotelina-1/metabolismo , Fígado/metabolismo , Animais , Northern Blotting , Células Cultivadas , Cicloeximida/farmacologia , Regulação para Baixo/fisiologia , Endotelina-1/farmacologia , Endotélio/citologia , Endotélio/metabolismo , Radioisótopos do Iodo , Células de Kupffer/metabolismo , Fígado/citologia , Masculino , Fosfatidilinositóis/metabolismo , Ligação Proteica , Proteínas Tirosina Quinases/metabolismo , RNA Mensageiro/metabolismo , Ratos , Ratos Sprague-Dawley , Receptor de Endotelina B , Receptores de Endotelina/metabolismo , Transdução de Sinais/fisiologia , Fatores de Tempo
2.
Biochim Biophys Acta ; 1073(3): 486-92, 1991 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-2015273

RESUMO

Previously, we have used the isolated perfused rat brain (IPRB) to demonstrate authentic cerebral synthesis of the lipid mediator platelet-activating-factor (Kumar, R., Harvey, S.A.K., Kester, M., Hanahan, D.J. and Olson, M.S. (1988) Biochim. Biophys. Acta 963, 375-383). The present study demonstrates that this fluorocarbon perfusion technique maintains the integrity of the blood-brain barrier (BBB), as evidenced by the small volume (1.77-3.33%) accessible to [carboxyl-14C]inulin. 51-66% of the brain was accessible to 3H2O, except for the spinal cord which is poorly perfused (16% accessible to 3H2O). There is no effective perfusion of muscle tissue associated with the preparation (less than 6% accessible to 3H2O). Fast Fourier Transform analysis of digitized EEG data showed that in low frequency bands (less than 7.5 Hz) the IPRB had reduced electrical activity relative to the whole conscious animal. The GABA antagonist bicuculline, which has convulsant effects in vivo, causes a 3-4-fold increase in overall (root-mean-square) electrical activity, but decreases further the relative amplitude of low frequencies. With appropriate corrections, measurement of the oxygen consumption of the IPRB can be made without the necessity for venous cannulation. Oxygen consumption of the IPRB is flow-dependent. At a perfusion rate of 1.54 ml/min per g, unstimulated oxygen consumption of the IPRB is 2.07-2.23 mumol/min per g, or 67-72% of the consumption of the brain in vivo. Administration of bicuculline to the IPRB causes a 31% increase in lactate efflux, but only a 15% increase in oxygen uptake, suggesting that the preparation becomes functionally ischemic. Measurement of ATP/ADP levels in control and bicuculline-treated IPRBs confirms this. Other workers have used the IPRB as a model for the cerebral effects of pharmacological agents and of metabolic insult. The present study shows that under various experimental conditions oxygen uptake, analytical EEG measurements, and the integrity of the blood-brain barrier all can be monitored.


Assuntos
Encéfalo/efeitos dos fármacos , Eletroencefalografia/efeitos dos fármacos , Fluorocarbonos/farmacologia , Consumo de Oxigênio/efeitos dos fármacos , Animais , Bicuculina/farmacologia , Barreira Hematoencefálica/efeitos dos fármacos , Encéfalo/anatomia & histologia , Encéfalo/metabolismo , Técnicas In Vitro , Lactatos/metabolismo , Masculino , Modelos Biológicos , Perfusão , Ratos , Ratos Endogâmicos
3.
Biochim Biophys Acta ; 963(2): 375-83, 1988 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-3196741

RESUMO

The synthesis of platelet-activating factor (PAF, 1-O-alkyl-2-acetyl-sn-glycero-3-phosphocholine) in rat brain was evaluated. Extracted PAF was characterized using standard HPLC and TLC techniques, and by correlation of its bioactivity with the acetylation state of the 2-position of the molecule. PAF was quantified by bioassay, its ability to cause [3H]serotonin release from washed rabbit platelets. The low basal level of PAF (0.25 +/- 0.15 pmol/g wet wt., mean +/- S.E.) in the brain of the intact rat was greatly increased by intraperitoneal injection of the chemoconvulsant drugs picrotoxin or bicuculline, to levels of 10.68 +/- 2.18 and 4.97 +/- 0.75 pmol/g wet wt., respectively. Electroconvulsion also increased brain PAF, to 1.76 +/- 0.30 pmol/g wet wt. Equivalent experiments using bicuculline in the isolated perfused rat brain yielded qualitatively similar results, indicating that the production of PAF in the brain is independent of systemic metabolism. When a 32P-labeled nerve-ending (synaptosome) preparation from rat brain was challenged with synthetic PAF (denoted AGEPC) at 0.1 nM concentration, responses were observed consistent with accelerated turnover of polyphosphoinositides. AGEPC also caused an increase in the Na+-Ca2+ exchange of synaptic membrane vesicles. Furthermore, AGEPC infused into the vasculature of the isolated perfused rat brain caused changes consistent with an increase in blood-brain barrier permeability, although AGEPC did not itself significantly penetrate the blood-brain barrier. It is concluded from these studies that PAF is synthesized within the rat brain in response to convulsant stimuli and that one of its effects is to accelerate synaptic polyphosphoinositide turnover. In addition, circulating PAF can influence blood-brain barrier permeability without itself penetrating the blood-brain barrier.


Assuntos
Encéfalo/metabolismo , Fator de Ativação de Plaquetas/biossíntese , Animais , Encéfalo/efeitos dos fármacos , Técnicas In Vitro , Cinética , Masculino , Fosfatos/metabolismo , Fosfolipídeos/biossíntese , Fator de Ativação de Plaquetas/isolamento & purificação , Fator de Ativação de Plaquetas/farmacologia , Ratos , Ratos Endogâmicos , Convulsões/metabolismo , Sinaptossomos/efeitos dos fármacos , Sinaptossomos/metabolismo
4.
J Am Coll Cardiol ; 26(7): 1630-6, 1995 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-7594096

RESUMO

OBJECTIVES: This study was designed to assess the angiographic and prognostic implications of an exaggerated systolic blood pressure response to exercise ("exercise hypertension") in adults undergoing evaluation for suspected coronary artery disease. BACKGROUND: The clinical implications of exercise hypertension are unclear. METHODS: Subjects for this prospective cohort study were derived from a consecutive sample of 9,608 adults who were referred for treadmill testing and who augmented their systolic blood pressure by at least 10 mm Hg. There were 594 subjects who underwent coronary angiography within 90 days of treadmill testing. Exercise hypertension was defined as a peak exercise systolic blood pressure > or = 210 mm Hg in men and > or = 190 mm Hg in women. Severe angiographic coronary disease was defined as left main coronary artery disease (> or = 50% diameter stenosis), three-vessel disease (> or = 70% diameter stenosis) or two-vessel disease with > or = 70% diameter stenosis of the proximal left anterior descending coronary artery. All-cause mortality was assessed during a follow-up period of approximately 2 years. RESULTS: Exercise hypertension was present in 196 subjects (33%). Severe coronary disease was less common in subjects with exercise hypertension (14% vs. 25%, odds ratio 0.51, 95% confidence interval [CI] 0.32 to 0.81, p = 0.004). Exercise hypertension remained associated with a lower rate of severe coronary disease even after adjusting for rest hypertension, age, gender, exercise capacity and other possible confounders. During the follow-up period, there were 23 deaths; only 2 occurred in the group with exercise hypertension. After adjusting for severity of coronary disease, exercise hypertension remained associated with a lower mortality rate (adjusted relative risk 0.20, 95% CI 0.05 to 0.84, p = 0.03). CONCLUSIONS: In adults evaluated for coronary artery disease, exercise hypertension is associated with a lower likelihood of angiographically severe disease and a lower adjusted mortality rate.


Assuntos
Pressão Sanguínea , Angiografia Coronária , Doença das Coronárias/diagnóstico , Teste de Esforço , Estudos de Coortes , Doença das Coronárias/diagnóstico por imagem , Doença das Coronárias/fisiopatologia , Eletrocardiografia , Feminino , Humanos , Hipertensão/etiologia , Masculino , Pessoa de Meia-Idade , Prognóstico , Estudos Prospectivos , Sístole
5.
J Am Coll Cardiol ; 30(3): 641-8, 1997 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-9283520

RESUMO

OBJECTIVES: We sought to determine the relative influence of estimated functional capacity and thallium-201 (Tl-201) single-photon emission computed tomographic (SPECT) findings on prediction of short-term all-cause and cardiac-related mortality. BACKGROUND: Decreased functional capacity and abnormal Tl-201 SPECT findings are predictive of increased cardiovascular risk and mortality. However, the relative importance of these variables as predictors of all-cause mortality is not well established. METHODS: Analyses were based on 3,400 consecutive adults undergoing symptom-limited exercise Tl-201 SPECT testing at the Cleveland Clinic Foundation between September 1990 and December 1993; none had previous invasive procedures, heart failure or valve disease. Estimated functional capacity, classified by age and gender, and thallium perfusion defects, expressed as a stress extent thallium score on a 12-segment scale, were analyzed to determine their relative prognostic importance during 2 years of follow-up. RESULTS: Of 3,400 patients, 108 (3.2%) died during follow-up; 32 deaths were identified as cardiac related. On univariable analysis, estimated functional capacity was a strong predictor of death, with 62 (57%) deaths occurring in patients achieving < 6 metabolic equivalents (METs) (log-rank chi-square 86, p < 0.0001). On multivariable analysis, the strongest independent predictors of all-cause mortality were fair or poor functional capacity (adjusted relative risk [RR] 3.96, 95% confidence interval [CI] 2.36 to 6.64, chi-square 27, p < 0.0001) and age (adjusted RR for 10 years 2.25, 95% CI 1.80 to 2.80, chi-square 27, p < 0.0001). The presence of SPECT thallium perfusion defects was a less powerful predictor of death (for each two additional segments with defects, adjusted RR 1.21, 95% CI 1.03 to 1.43, chi-square 5, p = 0.02). Cardiac mortality was predicted by both fair or poor functional capacity (adjusted RR 4.37, 95% CI 1.59 to 12.00, chi-square 8, p = 0.004) and by stress extent thallium score (adjusted RR 1.62, 95% CI 1.25 to 2.11, chi-square 13, p = 0.0003). CONCLUSIONS: In this clinically low risk group, estimated functional capacity was a strong and overwhelmingly important independent predictor of all-cause mortality among patients undergoing exercise Tl-201 SPECT testing. The extent of myocardial perfusion defects was of comparable importance for the prediction of cardiac mortality.


Assuntos
Teste de Esforço , Tolerância ao Exercício , Mortalidade , Tomografia Computadorizada de Emissão de Fóton Único , Adulto , Doença das Coronárias/diagnóstico , Doença das Coronárias/diagnóstico por imagem , Doença das Coronárias/fisiopatologia , Feminino , Cardiopatias/mortalidade , Humanos , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Prognóstico , Modelos de Riscos Proporcionais , Estudos Prospectivos , Radioisótopos de Tálio
6.
Biol Psychiatry ; 33(2): 93-9, 1993 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-8439609

RESUMO

Numerous studies have demonstrated a lateralized impairment of attention in schizophrenia. In this study, attention in schizophrenia is investigated with a task that involves centering a rod while blindfolded. Symptoms were rated on the Brief Psychiatric Rating Scale (BPRS) for each of the 20 schizophrenic subjects. The more symptomatic patients demonstrated a right-sided hemineglect compared to the less symptomatic patients (p = 0.013). Furthermore, the difference between more and less symptomatic patients was even more distinct when they were categorized by the BPRS schizophrenia subscale alone (p = 0.0025). These findings support the hypothesis that the pathophysiology of schizophrenia involves a lateralized defect in the control of attention, and that this defect is associated with the severity of symptoms. This raises the possibility that effects of neuroleptic medication may be asymmetric, which could account for some of the inconsistencies in studies of hemispheric dysfunction in schizophrenia.


Assuntos
Atenção/fisiologia , Encéfalo/fisiopatologia , Lateralidade Funcional/fisiologia , Esquizofrenia/diagnóstico , Adulto , Idoso , Feminino , Hospitalização , Humanos , Cinestesia/fisiologia , Masculino , Pessoa de Meia-Idade , Escalas de Graduação Psiquiátrica , Esquizofrenia/fisiopatologia , Índice de Gravidade de Doença , Tato/fisiologia
7.
Am J Cardiol ; 78(3): 278-83, 1996 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-8759804

RESUMO

Considerable controversy exists regarding whether women are less likely than men to be referred to coronary angiography after an abnormal noninvasive test. This prospective cohort study analyzed consecutive subjects (2,351 men and 1,318 women) with no prior history of invasive cardiac procedures who were referred for treadmill thallium testing at the Cleveland Clinic Foundation. The primary end point was performance of coronary angiography within 90 days of treadmill thallium testing. A secondary end point was all-cause mortality during 1.8 years of follow-up. Women were less likely than men to undergo coronary angiography (6% vs 14%, odds ratio [OR] 0.42, 95% confidence interval [Cl] 0.33 to 0.54, p < 0.001), but were also less likely to have an abnormal thallium scan (8% vs 29%, p < 0.001). In logistic regression analyses with adjustment for thallium result and age, women were as likely as men to be referred for coronary angiography (adjusted OR 1.00, 95% Cl 0.75 to 1.34, p > 0.9). Women were less likely to have severe coronary disease on angiography (15% vs 30%, p = 0.006). During 1.8 years of follow-up there were 26 deaths (2%) among women and 84 deaths (4%) among men. After adjusting for age, thallium abnormalities, and clinical characteristics in Cox regression analyses, women had a lower mortality rate than men (relative risk 0.58, 95% Cl 0.36 to 0.94, p = 0.03). Thus, gender-related differences in referral for coronary angiography after treadmill thallium testing can be explained by a higher rate of abnormal tests in men. No evidence of a post-test gender bias was detected, but a pretest bias affecting referral to nuclear testing cannot be excluded. Furthermore, women have a lower prevalence of severe coronary disease and a lower adjusted mortality rate.


Assuntos
Angiografia Coronária , Teste de Esforço , Encaminhamento e Consulta , Radioisótopos de Tálio , Idoso , Viés , Cateterismo Cardíaco/estatística & dados numéricos , Angiografia Coronária/estatística & dados numéricos , Doença das Coronárias/diagnóstico , Doença das Coronárias/mortalidade , Teste de Esforço/métodos , Teste de Esforço/estatística & dados numéricos , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Ohio/epidemiologia , Prognóstico , Encaminhamento e Consulta/estatística & dados numéricos , Fatores Sexuais , Fatores de Tempo , Tomografia Computadorizada de Emissão de Fóton Único/métodos , Tomografia Computadorizada de Emissão de Fóton Único/estatística & dados numéricos
8.
Am J Cardiol ; 81(2): 219-24, 1998 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-9591907

RESUMO

Exercise treadmill testing is frequently performed to screen for coronary artery disease (CAD) in asymptomatic individuals; however, its clinical value is unclear. We examined a consecutive cohort of asymptomatic adults undergoing exercise treadmill testing at the Cleveland Clinic Foundation between September 1990 and December 1993. End points included (1) identification of subjects with severe CAD and (2) performance of any second diagnostic study within 90 days of the index exercise treadmill test. Screening exercise treadmill testing was performed in 4,334 adults (median age 51, 89% men); only 34% had > or = 1 cardiac risk factor and 15% exhibited an abnormal response to exercise. A second test after treadmill testing was performed in 215 patients (in 110, coronary angiography; in 105, stress thallium scintigraphy, followed by coronary angiography in 16). The strongest predictor of referral for a second test was an ischemic ST-segment response (adjusted odds ratio [OR] 34, 95% confidence intervals [Cl] 24 to 47, p < 0.0001). The only clinical variable independently associated with referral for a second test was female gender (adjusted OR 0.35, 95% CI 0.21 to 0.60, p <0.0001). Of the 126 patients who underwent coronary angiography, severe CAD was identified in only 19 individuals (10.44% of the original cohort, 95% CI 0.26% to 0.62%); coronary artery bypass grafting was performed in 14 of these patients. The estimated cost of exercise treadmill testing to identify 1 case of severe CAD for which surgical revascularization may provide a survival benefit was $39,623. The estimated cost per year of life saved was at least $55,274. Thus, as used in actual practice in 1 center, screening exercise treadmill testing has a low yield and is costly. This is perhaps in part because of the low-risk population that was selected and the failure to incorporate pretest variables, increasing probability of disease into post-test clinical decision making.


Assuntos
Doença das Coronárias/diagnóstico , Teste de Esforço/economia , Adulto , Angioplastia com Balão , Angiografia Coronária , Ponte de Artéria Coronária , Doença das Coronárias/mortalidade , Doença das Coronárias/cirurgia , Análise Custo-Benefício , Tomada de Decisões , Eletrocardiografia , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Ohio/epidemiologia , Valor Preditivo dos Testes , Estudos Prospectivos , Taxa de Sobrevida
9.
Am J Cardiol ; 76(17): 1228-32, 1995 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-7503001

RESUMO

Inappropriate chronotropic response to exercise has been observed to correlate with poor prognosis in patients with coronary disease, but the mechanism for this association is not well defined. We attempted to examine the association between chronotropic response to exercise and angiographic severity of coronary disease in patients with suspected or stable coronary artery disease. The chronotropic response, expressed as peak heart rate, chronotropic index (ratio of heart rate reserve and metabolic reserve utilized), or percent maximal heart rate achieved, was correlated with angiographic findings obtained within 180 days of the test. Significant coronary disease was defined as > or = 1 stenosis of > or = 50% in a major epicardial artery or its main branches; severe coronary disease was defined as > or = 50% stenosis in all 3 epicardial arteries, or in the left main coronary trunk, or 2-vessel disease with > or = 70% proximal left anterior descending artery stenosis. We observed that peak heart rate and percent maximal heart rate achieved were independent negative predictors of both significant and severe coronary disease by logistic regression. The chronotropic index predicted severe coronary disease only. All 3 parameters of chronotropic response exhibited a significant gradient of abnormality across the spectrum of coronary disease (p < 0.01 for all), expressed by the number of vessels involved and correlated with left anterior descending artery involvement (p < 0.05 for all). We conclude that chronotropic response to exercise predicts the presence and angiographic severity of coronary disease. This association is likely related to the proportion of left ventricular myocardium rendered ischemic during stress.


Assuntos
Angiografia Coronária , Doença das Coronárias/fisiopatologia , Exercício Físico/fisiologia , Frequência Cardíaca , Idoso , Constrição Patológica , Teste de Esforço , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes
10.
Eur J Pharmacol ; 415(1): 13-8, 2001 Mar 09.
Artigo em Inglês | MEDLINE | ID: mdl-11245846

RESUMO

The Ca2+ ionophore A23187 is routinely used to illustrate the extracellular Ca2+-dependence of a variety of cellular reactions. We found that A23187-induced hydrolysis of phosphoinositides to various inositol phosphates in rat Kupffer cells was accompanied by their release from the cells. The synthesis and release of inositol phosphates was A23187 concentration-dependent (0.5-10 microM), and was apparent at the lowest concentration tested. A23187-induced release of inositol phosphates increased time-dependently, was apparent at 5 s of stimulation and maximal at 20 min. The effects of A23187 were reversed by EGTA. The integrity of the cells was not affected by A23187 treatment as indicated by their exclusion of trypan blue and the lack of release of lactate dehydrogenase. We propose that such effects should be considered while evaluating the Ca2+-dependence of biological processes based on the actions of A23187.


Assuntos
Calcimicina/farmacologia , Fosfatos de Inositol/metabolismo , Ionóforos/farmacologia , Células de Kupffer/efeitos dos fármacos , Animais , Permeabilidade da Membrana Celular/efeitos dos fármacos , Células Cultivadas , Quelantes/farmacologia , Relação Dose-Resposta a Droga , Ácido Egtázico/farmacologia , Células de Kupffer/citologia , Células de Kupffer/metabolismo , Masculino , Fator de Ativação de Plaquetas/farmacologia , Ratos , Ratos Sprague-Dawley , Fatores de Tempo
11.
Eur J Pharmacol ; 367(1): 7-11, 1999 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-10082258

RESUMO

Release of nitric oxide occurs as a consequence of glutamate stimulation of NMDA receptors and is dependent upon calcium-calmodulin activation of the enzyme nitric oxide synthase. Since nitric oxide may serve as an intracellular messenger for NMDA glutamatergic neurons, it could be hypothesized that blockade of its synthesis may produce pharmacological effects similar to those of NMDA receptor antagonists. The purpose of the present study was to compare the effects of nitric oxide synthase inhibitors to those of the high affinity NMDA open channel blocker phencyclidine in drug discrimination, a pharmacologically selective procedure in which phencyclidine produces distinctive effects. Rats were trained to discriminate 2 mg/kg phencyclidine from saline in a standard two-lever discrimination task with food reward. Whereas phencyclidine dose-dependently substituted for itself, 7-nitroindazole, L-NAME (N(G)-nitro-L-arginine methyl ester), and L-NOARG (N(G)-nitro-L-arginine) failed to substitute for phencyclidine when administered intraperitoneally. L-NAME and 7-nitroindazole were tested up to doses that disrupted responding, providing evidence that a behaviorally-relevant dosage range was evaluated. Although these results conflict with those of a previous study which found that nitric oxide synthase inhibitors substituted for phencyclidine and produced phencyclidine-like catalepsy in pigeons, they are consistent with research showing that these drugs did not produce phencyclidine-like pharmacological effects in behavioral procedures in rats.


Assuntos
Discriminação Psicológica/efeitos dos fármacos , Inibidores Enzimáticos/farmacologia , Antagonistas de Aminoácidos Excitatórios/farmacologia , Óxido Nítrico Sintase/antagonistas & inibidores , Fenciclidina/farmacologia , Cloreto de Sódio/farmacologia , Animais , Aprendizagem por Discriminação , Relação Dose-Resposta a Droga , Indazóis/farmacologia , Masculino , NG-Nitroarginina Metil Éster/farmacologia , Nitroarginina/farmacologia , Desempenho Psicomotor/efeitos dos fármacos , Ratos , Ratos Sprague-Dawley
12.
Laryngoscope ; 107(9): 1199-202, 1997 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-9292603

RESUMO

Proper healing after surgery of the external auditory canal and open-cavity mastoid depend on epithelialization of exposed surfaces. This may be retarded by the formation of abundant granulation tissue or cicatrix, which can be dealt with by the use of thin, split-thickness skin grafts. This technique, which has received little attention in the literature, is described in detail and nine cases treated for various disorders are illustrated. Patient ages ranged from 5 to 80 years and the mean follow-up was 17.2 years. Results, complications, and caveats for successful grafting are presented.


Assuntos
Meato Acústico Externo/cirurgia , Otopatias/cirurgia , Processo Mastoide/cirurgia , Transplante de Pele/métodos , Adulto , Idoso , Idoso de 80 Anos ou mais , Carcinoma Basocelular/cirurgia , Criança , Pré-Escolar , Colesteatoma da Orelha Média/cirurgia , Cicatriz/patologia , Meato Acústico Externo/anormalidades , Deformidades Adquiridas da Orelha/etiologia , Deformidades Adquiridas da Orelha/cirurgia , Neoplasias da Orelha/cirurgia , Granuloma Eosinófilo/cirurgia , Epitélio/fisiologia , Seguimentos , Tecido de Granulação/patologia , Humanos , Pessoa de Meia-Idade , Recidiva Local de Neoplasia/cirurgia , Osteotomia/métodos , Recidiva , Transplante de Pele/efeitos adversos , Resultado do Tratamento , Timpanoplastia/efeitos adversos , Cicatrização
13.
Laryngoscope ; 109(6): 911-4, 1999 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-10369281

RESUMO

OBJECTIVES/HYPOTHESIS: Multiple techniques of ossicular reconstruction have been advocated for hearing rehabilitation in the setting of chronic otitis media No single method can adequately address the clinical spectrum of disease severity. In the situation of a severely diseased ear requiring a canal wall down (CWD) mastoidectomy in the presence of an intact stapes superstructure, the authors have employed a double cartilage block (DCB) ossiculoplasty. The technique and short-term results are reviewed. STUDY DESIGN: Retrospective chart review in a tertiary referral otologic practice. METHODS: Twenty-three patients underwent a CWD tympanomastoidectomy with DCB ossiculoplasty. Ages ranged from 6 to 85 years (mean, 36.1 y). The majority of ears were actively draining at the time of surgery (83%) and most procedures were revisions of prior mastoidectomies (74%). Audiometric data (mean postoperative follow-up, 19.5 mo) were calculated according to 1995 American Academy of Otolaryngology-Head and Neck Surgery guidelines. RESULTS: Audiometric results were available in 20 patients. The mean air-bone gap (ABG) was 23.8 dB after surgery. Closure of the ABG to within 20 dB was achieved in 10 of 20 patients (50%). No cases of DCB extrusion have occurred to date. CONCLUSIONS: The DCB represents an excellent alternative to biocompatible prostheses for ossicular reconstruction in the setting of severe chronic ear disease. As with all methods of ossiculoplasty, long-term follow-up will be necessary to determine if this technique remains stable in the hostile environment in which it has been employed.


Assuntos
Cartilagem da Orelha/cirurgia , Ossículos da Orelha/cirurgia , Perda Auditiva Condutiva/etiologia , Perda Auditiva Condutiva/prevenção & controle , Otite Média/cirurgia , Procedimentos de Cirurgia Plástica/métodos , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Audiometria , Criança , Doença Crônica , Feminino , Humanos , Masculino , Prontuários Médicos , Pessoa de Meia-Idade , Substituição Ossicular , Estudos Retrospectivos , Resultado do Tratamento
14.
Laryngoscope ; 106(1 Pt 1): 6-9, 1996 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-8544630

RESUMO

The oculocephalic response (OCR) is a simple office maneuver that assesses the vestibulo-ocular reflex (VOR). An abnormal response is manifested clinically as refixation saccades following a rapid horizontal head movement. Because little attention has been given to the OCR in the literature, a prospective study was undertaken with 112 consecutive patients who presented with dizziness and underwent OCR testing followed by caloric evaluation. Agreement was good between the OCR and caloric evaluation (kappa = 0.44). Specificity was quite high (97%); sensitivity was found to be less (39%). Positive (68%) and negative (90%) predictive values of the OCR illustrate that the clinician can often anticipate the results of caloric testing based on this response. This easily performed test of the VOR is a useful tool in the evaluation of the dizzy patient.


Assuntos
Tontura/diagnóstico , Fixação Ocular , Cabeça/fisiologia , Movimentos Sacádicos , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Testes Calóricos , Criança , Feminino , Humanos , Masculino , Métodos , Pessoa de Meia-Idade , Movimento , Estudos Prospectivos , Sensibilidade e Especificidade
15.
Laryngoscope ; 107(11 Pt 1): 1445-50, 1997 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-9369388

RESUMO

Although use of the laser for stapedectomy has become common in recent years, controversy remains regarding whether the CO2 or visible-spectrum lasers (argon and KTP) are best suited for this operation. The main concern has been the potential for thermal injury to the inner ear with the visible-spectrum lasers attributable to their absorption characteristics. To further investigate this issue, the author performed 20 laser stapedectomies on adult chinchillas. Following placement of a 0.127-mm-diameter copper/constantan thermocouple (sampling at 12 Hz) beneath the footplate on the medial wall of the vestibule via a distant fenestration site, thermal changes with a micromanipulator-based CO2 and fiberoptic KTP system were compared. This was the first live animal model comparison of these two lasers. There was no statistical difference in the mean temperature elevation between the two systems (P = 0.395).


Assuntos
Dióxido de Carbono , Lasers , Cirurgia do Estribo/métodos , Condutividade Térmica , Animais , Chinchila , Terapia a Laser , Fatores de Tempo
16.
Laryngoscope ; 100(12): 1294-300, 1990 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-2243521

RESUMO

Gadolinium-enhanced magnetic resonance imaging has been used to evaluate 20 patients with surgically confirmed facial nerve lesions. When the nerve could be seen, gadolinium-enhanced magnetic resonance imaging accurately revealed the lesion site as well as the known extent, which in some cases was not predicted by topognostic testing. This technique appears to provide accurate lesion-site testing and may have importance in surgical planning. Currently used topognostic tests of facial nerve function are frequently inaccurate and can only determine the most proximal lesion site when there are multiple or extensive lesions. The focal nerve enhancement seen in nerve injury, globally increased signal intensity within the temporal bone after trauma, and increased signal intensity within the dura after surgery can occasionally mask nerve lesions and may be confused with tumors.


Assuntos
Traumatismos do Nervo Facial , Paralisia Facial/diagnóstico , Imageamento por Ressonância Magnética , Adulto , Nervo Facial/patologia , Paralisia Facial/etiologia , Paralisia Facial/patologia , Feminino , Gadolínio DTPA , Humanos , Masculino , Pessoa de Meia-Idade , Compostos Organometálicos , Ácido Pentético
17.
Laryngoscope ; 105(10): 1053-7, 1995 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-7564834

RESUMO

Despite an increasing incidence of gunshot wounds to the temporal bone, there is little in the literature regarding management of survivors of these serious injuries. Twelve patients were treated for such wounds between 1986 and 1994. The most frequent presentations were cranial nerve injury, especially facial paralysis (9 patients), hearing loss (7), vascular injury (4), and vestibular dysfunction (3). Persistent cerebrospinal fluid otorrhea was uncommon (1 patient) in this series. Computed tomography and audiovestibular testing were helpful in evaluating the severity of injury and guiding the surgical approach when necessary. Electroneurography was helpful in evaluating facial nerve function; however, documented disruption of the facial nerve canal in itself was considered an indication for surgical exploration. Other indications for surgical intervention included evidence of dural tear, vascular injury, and severe disruption of the external auditory canal.


Assuntos
Osso Temporal/lesões , Ferimentos por Arma de Fogo/diagnóstico , Adolescente , Adulto , Traumatismos dos Nervos Cranianos , Paralisia Facial/etiologia , Feminino , Transtornos da Audição/etiologia , Humanos , Masculino , Estudos Retrospectivos , Osso Temporal/diagnóstico por imagem , Osso Temporal/cirurgia , Tomografia Computadorizada por Raios X , Wisconsin , Ferimentos por Arma de Fogo/complicações , Ferimentos por Arma de Fogo/cirurgia
18.
Laryngoscope ; 103(6): 594-9, 1993 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-8388974

RESUMO

An innovative hydroxylapatite canal wall implant underlies a new technique for reconstructing canal wall defects in well-pneumatized "disease-free" mastoid cavities. Previous primary reconstruction involving soft-tissue techniques were not always optimal, depending on the size of the defect. The new hard implant provides lasting canal wall contour, and the implantation technique can be duplicated by other otolaryngologists. Our experience with the implant is described in 11 patients (implant duration 2 to 37 months) using a modification of the technique described by Grote (1986). The implant is biocompatible, being incorporated into surrounding tissues. Indications, contraindications (relative and absolute), and the intraoperative sculpturing method are presented. Long-term and short-term complications are reviewed with suggestions to minimize complications.


Assuntos
Materiais Biocompatíveis , Meato Acústico Externo/cirurgia , Hidroxiapatitas , Processo Mastoide/cirurgia , Próteses e Implantes , Adolescente , Adulto , Idoso , Criança , Colesteatoma/cirurgia , Durapatita , Meato Acústico Externo/patologia , Meato Acústico Externo/fisiopatologia , Otopatias/cirurgia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Osseointegração , Desenho de Prótese , Retalhos Cirúrgicos/métodos , Resultado do Tratamento
19.
Laryngoscope ; 104(10): 1206-12, 1994 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-7934589

RESUMO

A modification of the liberatory maneuver was used to treat 25 patients with benign paroxysmal positional vertigo (BPPV). The modified liberatory maneuver relieved symptoms without recurrence in 11 (44%) patients. A partial response was noted in 6 (24%) patients, and there was no improvement in 8 (32%) patients. Follow-up ranged from 1 to 20 months (median 4.0 months). Patient age was not predictive of response to treatment. Duration of symptoms before treatment, however, was greater in nonresponders (median 15.5 months) than in complete (median 5.0 months) or partial (median 3.5 months) responders. The modified liberatory maneuver takes approximately 5 minutes to perform and provides effective treatment in two thirds of patients who suffer from BPPV.


Assuntos
Modalidades de Fisioterapia/métodos , Vertigem/terapia , Adulto , Idoso , Idoso de 80 Anos ou mais , Audiometria , Audiometria de Resposta Evocada , Eletronistagmografia , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Postura , Recidiva , Vertigem/diagnóstico , Vertigem/fisiopatologia
20.
Otolaryngol Head Neck Surg ; 121(1): 18-22, 1999 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-10388870

RESUMO

The role of canal-wall-down (CWD) versus intact-canal-wall (ICW) mastoidectomy in the treatment of chronic otitis media with or without cholesteatoma remains a debated issue. Although past conventional wisdom has held that CWD mastoid surgery leads to a "safe" ear and is technically less demanding than the more controversial ICW mastoidectomy, this is often not the case. Although our preference is an ICW technique when possible, 47 of 109 (43%) mastoid procedures for chronic otitis media performed between January 1993 and June 1996 involved a CWD mastoid cavity. More than two thirds of these procedures (32 of 47) represented revision surgery, the most common indication being a poorly contoured, preexisting CWD mastoidectomy with persistent otorrhea. A dry, well-epithelialized ear was obtained in 90% of cases. Our preferred method of ossicular reconstruction (double cartilage block ossiculoplasty) is detailed, and hearing results according to American Academy of Otolaryngology Head and Neck Surgery guidelines are reported.


Assuntos
Processo Mastoide/cirurgia , Otite Média/cirurgia , Procedimentos Cirúrgicos Otológicos/métodos , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Pré-Escolar , Colesteatoma da Orelha Média/cirurgia , Doença Crônica , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Reoperação , Estudos Retrospectivos , Falha de Tratamento , Resultado do Tratamento
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