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1.
Oncogene ; 34(5): 546-57, 2015 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-24469056

RESUMO

Epithelial-mesenchymal transition (EMT) is an essential step for tumor progression, although the mechanisms driving EMT are still not fully understood. In an effort to investigate these mechanisms, we observed that heregulin (HRG)-mediated activation of HER2, or HER2 overexpression, resulted in EMT, which is accompanied with increased expression of a known EMT regulator Slug, but not TWIST or Snail. We then investigated how HER2 induced Slug expression and found, for the first time, that there are four consensus HSF sequence-binding elements (HSEs), the binding sites for heat shock factor-1 (HSF-1), located in the Slug promoter. HSF-1 bound to and transactivated the Slug promoter independent of heat shock, leading to Slug expression in breast cancer cells. Mutation of the putative HSEs ablated Slug transcriptional activation induced by HRG or HSF-1 overexpression. Knockdown of HSF-1 expression by siRNA reduced Slug expression and HRG-induced EMT. The positive association between HSF-1 and Slug was confirmed by immunohistochemical staining of a cohort of 100 invasive breast carcinoma specimens. While investigating how HER2 activated HSF-1 independent of heat shock, we observed that HER2 activation resulted in concurrent phosphorylation of Akt and HSF-1. We then observed, also for the first time, that Akt directly interacted with HSF-1 and phosphorylated HSF-1 at S326. Inhibition of Akt using siRNA, dominant-negative Akt mutant, or small molecule inhibitors prevented HRG-induced HSF-1 activation and Slug expression. Conversely, constitutively active Akt induced HSF-1 phosphorylation and Slug expression. HSF-1 knockdown reduced the ability of Akt to induce Slug expression, indicating an essential role that HSF-1 plays in Akt-induced Slug upregulation. Altogether, our study uncovered the existence of a novel Akt-HSF-1 signaling axis that leads to Slug upregulation and EMT, and potentially contributes to progression of HER2-positive breast cancer.


Assuntos
Neoplasias da Mama/genética , Proteínas de Ligação a DNA/biossíntese , Transição Epitelial-Mesenquimal/genética , Proteína Oncogênica v-akt/metabolismo , Fatores de Transcrição/biossíntese , Animais , Neoplasias da Mama/metabolismo , Neoplasias da Mama/patologia , Proteínas de Ligação a DNA/genética , Feminino , Regulação Neoplásica da Expressão Gênica , Fatores de Transcrição de Choque Térmico , Resposta ao Choque Térmico/genética , Humanos , Células MCF-7 , Neuregulina-1/administração & dosagem , Proteína Oncogênica v-akt/genética , Fosforilação/efeitos dos fármacos , RNA Interferente Pequeno , Receptor ErbB-2/genética , Transdução de Sinais/efeitos dos fármacos , Fatores de Transcrição da Família Snail , Fatores de Transcrição/genética
2.
J Neurol ; 255(6): 848-52, 2008 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-18481035

RESUMO

We evaluated the effects of the levo (l) enantiomer of amphetamine sulfate on cognitive function in multiple sclerosis (MS) patients. Using a counterbalanced within-subjects design, 19 MS patients received four single-dose administrations of placebo, 15 mg, 30 mg, or 45 mg of l-amphetamine. Neuropsychological tests measuring processing speed and memory served as the primary outcomes. Performance on tests of processing speed were improved following the 45 mg condition and the largest effects were observed on the Symbol Digit Modalities Test, which measures visual processing speed and working memory. While episodic memory test effects were in the expected direction, the findings were not statistically significant. These preliminary findings show promise for the use of l-amphetamine for the symptomatic treatment of slowed mental processing in MS. Further placebo-controlled trials are needed to confirm these findings.


Assuntos
Anfetamina/administração & dosagem , Transtornos Cognitivos/tratamento farmacológico , Transtornos Cognitivos/etiologia , Esclerose Múltipla/complicações , Esclerose Múltipla/tratamento farmacológico , Adulto , Anfetamina/efeitos adversos , Estimulantes do Sistema Nervoso Central/administração & dosagem , Estimulantes do Sistema Nervoso Central/efeitos adversos , Cognição/efeitos dos fármacos , Cognição/fisiologia , Relação Dose-Resposta a Droga , Método Duplo-Cego , Esquema de Medicação , Feminino , Humanos , Masculino , Memória de Curto Prazo/efeitos dos fármacos , Memória de Curto Prazo/fisiologia , Pessoa de Meia-Idade , Esclerose Múltipla/psicologia , Testes Neuropsicológicos , Efeito Placebo , Placebos , Tempo de Reação/efeitos dos fármacos , Tempo de Reação/fisiologia , Resultado do Tratamento
3.
J Sports Med Phys Fitness ; 46(4): 585-9, 2006 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-17119524

RESUMO

AIM: The aim of the study is to evaluate the test-retest reliability of measures of isokinetic and isometric leg strength and joint function among individuals exhibiting symptoms of mild osteoarthritis. Reliable procedures are needed to assess the effectiveness of an intervention on osteoarthritic symptoms. METHODS: Test-retest reliability of two leg strength protocols was assessed using the intraclass correlation coefficient (R). Testing was completed on two occasions separated by 7 days. Eighteen subjects (9 male and 9 female; 54.1+/-11 years) completed an isokinetic testing trial, which consisted of a set of 5 maximal repetitions of the quadriceps and hamstrings at 60 deg/s followed by a set of 15 maximal contractions at 180 deg/s with a 2-min rest between sets and an isometric testing trial, which consist of 3 maximal contractions of the quadriceps for 6 s with a 30-s rest between contractions at 30, 45, and 80 degrees of knee flexion for a total of 9 isometric contractions. A 90-s rest occurred between angles. RESULTS: Most of the isokinetic variables showed moderate to high intraclass reliability (ICC). Two of the calculated isokinetic variables (work fatigue at 180 degrees /s for extension and for flexion) showed low intraclass reliability (ICC=0.78, resp. ICC=0.6). All calculated ICC values of the isometric variables were moderate to high. CONCLUSIONS: Test-retest reliability of isokinetic and isometric leg strength was high, allowing the intervention protocol to monitor changes in leg strength and joint function among those exhibiting symptoms of mild osteoarthritis.


Assuntos
Exercício Físico/fisiologia , Força Muscular , Músculo Esquelético/fisiologia , Osteoartrite/fisiopatologia , Fenômenos Biomecânicos , Feminino , Humanos , Contração Isométrica/fisiologia , Articulação do Joelho/fisiologia , Perna (Membro) , Masculino , Pessoa de Meia-Idade , Reprodutibilidade dos Testes , Torque
4.
J Toxicol Environ Health A ; 64(5): 385-415, 2001 Nov 09.
Artigo em Inglês | MEDLINE | ID: mdl-11700005

RESUMO

Groups of 16 Sprague-Dawley rats each were exposed by whole-body inhalation methods to JP-8 jet fuel at the highest vapor concentration without formation of aerosol (1,000 +/- 10% mg/m3); to 50% of this concentration (500 +/- 10% mg/m3); or to treated room air (70 +/- 81 L/min) for 6 h/d, 5 d/wk, for 6 wk (180 h). Although two subjects died of apparent kidney complications during the study, no other change in the health status of exposed rats was observed, including rate of weight gain. Following a 65-d period of rest, rats were evaluated for their capacity to learn and perform a series of operant tasks. These tasks ranged in difficulty from learning of a simple food-reinforced lever pressing response, to learning a task in which subjects were required to emit up to four-response chains of pressing three different levers (e.g., press levers C, R, L, then C). It was shown that repeated exposure to 1,000 mg/m3 JP-8 vapor induced significant deficits in acquisition or performance of moderately difficult or difficult tasks, but not simple learning tasks, as compared to those animals exposed to 500 mg/m3. Learning/performance of complex tasks by the 500-mg/m3 exposure group generally exceeded the performance of control animals, while learning by the 1,000-mg/m3 group was nearly always inferior to controls, indicating possible "neurobehavioral" hormesis. These findings appear consistent with some previously reported data for operant performance following acute exposure to certain hydrocarbon constituents of JP-8 (i.e., toluene, xylenes). There has, however, been little previously published research demonstrating long-term learning effects for repeated hydrocarbon fuel exposures. Examination of regional brain tissues from vapor-exposed rats indicated significant changes in levels of dopamine in the cerebral cortex and DOPAC in the brainstem, measured as long as 180 d postexposure, as compared to controls.


Assuntos
Condicionamento Operante/efeitos dos fármacos , Combustíveis Fósseis/toxicidade , Administração por Inalação , Animais , Peso Corporal/efeitos dos fármacos , Encéfalo/patologia , Química Encefálica/efeitos dos fármacos , Privação de Alimentos/fisiologia , Hidrocarbonetos/toxicidade , Masculino , Neurotransmissores/metabolismo , Ratos , Ratos Sprague-Dawley , Esquema de Reforço , Percepção Espacial/efeitos dos fármacos
5.
N Engl J Med ; 345(13): 935-40, 2001 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-11575284

RESUMO

BACKGROUND: Postoperative recovery of gastrointestinal function and resumption of oral intake are critical determinants of the length of hospital stay. Although opioids are effective treatments for postoperative pain, they contribute to the delayed recovery of gastrointestinal function. METHODS: We studied the effects of ADL 8-2698, an investigational opioid antagonist with limited oral absorption that does not readily cross the blood-brain barrier, on postoperative gastrointestinal function and the length of hospitalization. We randomly assigned 79 patients--including 1 whose surgery was canceled--to receive one capsule containing 1 mg or 6 mg of ADL 8-2698 or an identical-appearing placebo capsule two hours before major abdominal surgery and then twice daily until the first bowel movement or until discharge from the hospital. Data were analyzed for 26 patients in each of the three groups; all received opioids for postoperative pain relief. Observers who were unaware of the group assignments evaluated the outcomes. RESULTS: Fifteen patients underwent partial colectomy and 63 underwent total abdominal hysterectomy. Patients given 6 mg of ADL 8-2698 had significantly faster recovery of gastrointestinal function than those given placebo. The median time to the first passage of flatus decreased from 70 to 49 hours (P=0.03), the median time to the first bowel movement decreased from 111 to 70 hours (P=0.01), and the median time until patients were ready for discharge decreased from 91 to 68 hours (P=0.03). Effects in the group that received 1 mg of ADL 8-2698 were less pronounced. CONCLUSIONS: Selective inhibition of gastrointestinal opioid receptors by an antagonist with limited oral absorption that does not readily cross the blood-brain barrier speeds recovery of bowel function and shortens the duration of hospitalization.


Assuntos
Obstrução Intestinal/tratamento farmacológico , Antagonistas de Entorpecentes/uso terapêutico , Piperidinas/uso terapêutico , Complicações Pós-Operatórias/tratamento farmacológico , Adolescente , Adulto , Idoso , Analgésicos Opioides/efeitos adversos , Analgésicos Opioides/uso terapêutico , Colectomia , Defecação/efeitos dos fármacos , Sistema Digestório/efeitos dos fármacos , Feminino , Flatulência , Humanos , Histerectomia , Obstrução Intestinal/etiologia , Tempo de Internação , Masculino , Meperidina/efeitos adversos , Meperidina/uso terapêutico , Pessoa de Meia-Idade , Morfina/efeitos adversos , Morfina/uso terapêutico , Antagonistas de Entorpecentes/farmacologia , Dor Pós-Operatória/tratamento farmacológico , Piperidinas/farmacologia , Complicações Pós-Operatórias/induzido quimicamente , Receptores Opioides/efeitos dos fármacos , Fatores de Tempo
6.
J Toxicol Environ Health A ; 63(6): 397-428, 2001 Jul 20.
Artigo em Inglês | MEDLINE | ID: mdl-11482797

RESUMO

The U.S. Naval Service is anticipating transition from the nearly exclusive use of JP-5 jet fuel to predominant use of JP-8, consistent with the primary utilization by the U.S. Army, U.S. Air Force, and the militaries of most NATO countries. To compare the relative risk of repeated exposure to JP-5 versus JP-8 vapor, groups of 32 male Sprague-Dawley rats each were exposed for 6 h/d, 5 d/wk for 6 wk (180 h) to JP-8 jet fuel vapor (1,000 +/- 10% mg/m3), IP-5 vapor (1,200 +/- 10% mg/m3), or room air control conditions. Following a 65-d rest period, rats completed 10 tests selected from the Neurobehavioral Toxicity Assessment Battery (NTAB) to evaluate changes in performance capacity. Repeated exposure to JP-5 resulted in significant effects on only one test, forelimb grip strength (FGS), while exposure to JP-8 vapor resulted in a significant difference versus controls on appetitive reinforcer approach sensitization (ARAS). Rats were further evaluated for concentrations of major neurotransmitters and metabolites in five brain regions and in the blood serum. Levels of dopamine, the dopamine metabolite dihydroxyphenylacetic acid (DOPAC), and the serotonin metabolite homovanillic acid (HVA) were significantly modulated in various brain regions, as measured 85+ d postexposure. Similarly, serum levels of the serotonin metabolite 5-hydroxyindoleacetic acid (5-HIAA) were differentially modulated following JP-8 or JP-5 exposure. Results are compared to previously published research evaluating the neurotoxicity of repeated exposure to other hydrocarbon fuels and solvents.


Assuntos
Comportamento Animal/efeitos dos fármacos , Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , Hidrocarbonetos/toxicidade , Neurotransmissores/metabolismo , Ácido 3,4-Di-Hidroxifenilacético/metabolismo , Animais , Aprendizagem da Esquiva/efeitos dos fármacos , Peso Corporal/efeitos dos fármacos , Dopamina/metabolismo , Ácido Homovanílico/metabolismo , Hidrocarbonetos/administração & dosagem , Ácido Hidroxi-Indolacético/sangue , Exposição por Inalação , Masculino , Aprendizagem em Labirinto/efeitos dos fármacos , Atividade Motora/efeitos dos fármacos , Contração Muscular/efeitos dos fármacos , Inibição Neural/efeitos dos fármacos , Medição da Dor/efeitos dos fármacos , Ratos , Ratos Sprague-Dawley , Reflexo de Sobressalto/efeitos dos fármacos , Serotonina/metabolismo , Tempo
7.
Clin Pharmacol Ther ; 69(1): 66-71, 2001 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-11180040

RESUMO

ADL-8-2698 is a novel peripherally restricted opioid antagonist that may selectively prevent opioid-induced gastrointestinal effects without reversing analgesia. Gastrointestinal transit time (lactulose hydrogen breath test) was measured in 14 volunteers with oral and intravenous placebo, oral placebo and intravenous morphine (0.05 mg x kg(-1)), and oral ADL 8-2698 (4 mg) and intravenous morphine (0.05 mg x kg(-1)) in a double blind, cross-over study. Morphine prolonged gastrointestinal transit time from 69 to 103 minutes (P = .005); this was prevented by ADL 8-2698 (P = .004). Postoperatively, 45 patients were randomly assigned in a double-blind fashion to receive ADL 8-2698 (4 mg) or placebo and intravenous morphine (0.15 mg/kg) or to receive oral and intravenous placebo. Analgesia and pupil constriction were measured. Morphine analgesia and pupil constriction were unaffected by ADL 8-2698 and differed from placebo (P < .002). We conclude that ADL 8-2698 prevents morphine-induced increases in gastrointestinal transit time by means of selective peripheral opioid anitagonism without affecting central opioid analgesia.


Assuntos
Analgésicos Opioides/efeitos adversos , Gastroenteropatias/prevenção & controle , Morfina/efeitos adversos , Antagonistas de Entorpecentes/uso terapêutico , Piperidinas/uso terapêutico , Adulto , Analgésicos Opioides/antagonistas & inibidores , Analgésicos Opioides/uso terapêutico , Método Duplo-Cego , Interações Medicamentosas , Feminino , Gastroenteropatias/induzido quimicamente , Trânsito Gastrointestinal/efeitos dos fármacos , Humanos , Masculino , Dente Serotino/cirurgia , Morfina/antagonistas & inibidores , Morfina/uso terapêutico , Medição da Dor/efeitos dos fármacos , Dor Pós-Operatória/tratamento farmacológico , Dor Pós-Operatória/etiologia , Extração Dentária/efeitos adversos , Dente Impactado/cirurgia
8.
Toxicol Ind Health ; 17(5-10): 277-84, 2001 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-12539873

RESUMO

A mathematical description of particle clearance from the ciliated conducting airways (tracheobronchial region) of the lungs in rats was developed, assuming that particles on the mucus blanket behave as a fluid and adhere to principles of fluid flow described by the continuity equation. Effective particle transport velocities for given generations of airways were estimated from reported tracheal mucus velocities. Using typical rat airway geometry and estimated particle transport velocities, solutions of sets of rate equations for transport from each generation of airways were summed to estimate total particle clearance from the tracheobronchial region of the lung as a function of time. Aerosol particle size distribution (MMAD ranging from 0.1 to 4.2 microm, and sigma(g) from 1 to 2.7) and concentration data from several investigators were used to predict short-term, tracheobronchial clearance (retention) in rats up to 24 h following exposure. Comparisons between predicted and observed retention showed an average difference between model predictions, and observed fractional retention of initial lung or body burden was 4.9%, with a tendency toward underprediction of clearance of particles >3.0 microm.


Assuntos
Poluentes Atmosféricos/análise , Poluentes Atmosféricos/farmacocinética , Pulmão , Modelos Teóricos , Aerossóis , Movimentos do Ar , Animais , Carga Corporal (Radioterapia) , Previsões , Exposição por Inalação , Muco , Tamanho da Partícula , Ratos
9.
Electrophoresis ; 21(11): 2138-47, 2000 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-10892725

RESUMO

Male Sprague-Dawley rats were exposed by whole body inhalation to 1000 mg/m3 +/- 10% JP-8 jet fuel vapor or room air control conditions for 6 h/day, 5 days/week for six consecutive weeks. Following a rest period of 82 days rats were sacrificed, and liver and kidney tissues examined by proteomic methods for both total protein abundance and protein charge modification. Kidney and lung samples were solubilized and separated via large scale, high resolution two-dimensional electrophoresis (2-DE) and gel patterns scanned, digitized and processed for statistical analysis. Through the use of peptide mass fingerprinting, confirmed by sequence tag analysis, three altered proteins were identified and quantified. Numerical, but not significantly different increases were found in total abundance of lamin A (NCBI Accession No. 1346413) in the liver, and of 10-formyltetrahydrofolate dehydrogenase (10-FTHF DH, #1346044) and glutathione-S-transferase (GST; #2393724) in the kidneys of vapor-exposed subjects. Protein charge modification index (CMI) analysis indicated significant alterations (P < 0.001) in expressed lamin A and 10-FTHF DH. These persisting changes in liver and kidney proteins are discussed in terms of possible alterations in the functional capacity of exposed subjects.


Assuntos
Glutationa Transferase/metabolismo , Hidrocarbonetos/toxicidade , Rim/efeitos dos fármacos , Fígado/efeitos dos fármacos , Proteínas Nucleares/metabolismo , Proteoma , Sequência de Aminoácidos , Animais , Rim/enzimologia , Rim/metabolismo , Lamina Tipo A , Laminas , Fígado/enzimologia , Fígado/metabolismo , Masculino , Dados de Sequência Molecular , Ratos , Ratos Sprague-Dawley , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz
10.
N Engl J Med ; 342(1): 9-14, 2000 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-10620643

RESUMO

BACKGROUND: Invasive techniques such as amniocentesis and cordocentesis are used for diagnosis and treatment in fetuses at risk for anemia due to maternal red-cell alloimmunization. The purpose of our study was to determine the value of noninvasive measurements of the velocity of blood flow in the fetal middle cerebral artery for the diagnosis of fetal anemia. METHODS: We measured the hemoglobin concentration in blood obtained by cordocentesis and also the peak velocity of systolic blood flow in the middle cerebral artery in 111 fetuses at risk for anemia due to maternal red-cell alloimmunization. Peak systolic velocity was measured by Doppler velocimetry. To identify the fetuses with anemia, the hemoglobin values of those at risk were compared with the values in 265 normal fetuses. RESULTS: Fetal hemoglobin concentrations increased with increasing gestational age in the 265 normal fetuses. Among the 111 fetuses at risk for anemia, 41 fetuses did not have anemia; 35 had mild anemia; 4 had moderate anemia; and 31, including 12 with hydrops, had severe anemia. The sensitivity of an increased peak velocity of systolic blood flow in the middle cerebral artery for the prediction of moderate or severe anemia was 100 percent either in the presence or in the absence of hydrops (95 percent confidence interval, 86 to 100 percent for the 23 fetuses without hydrops), with a false positive rate of 12 percent. CONCLUSIONS: In fetuses without hydrops that are at risk because of maternal red-cell alloimmunization, moderate and severe anemia can be detected noninvasively by Doppler ultrasonography on the basis of an increase in the peak velocity of systolic blood flow in the middle cerebral artery.


Assuntos
Eritroblastose Fetal/diagnóstico por imagem , Artéria Cerebral Média/diagnóstico por imagem , Ultrassonografia Doppler de Pulso , Ultrassonografia Pré-Natal , Velocidade do Fluxo Sanguíneo , Incompatibilidade de Grupos Sanguíneos/complicações , Cordocentese , Eritroblastose Fetal/diagnóstico , Eritroblastose Fetal/etiologia , Eritrócitos/imunologia , Feminino , Sangue Fetal/química , Idade Gestacional , Hemoglobinas/análise , Humanos , Recém-Nascido , Isoanticorpos/sangue , Gravidez , Complicações Hematológicas na Gravidez , Estudos Prospectivos , Curva ROC , Valores de Referência , Isoimunização Rh , Sensibilidade e Especificidade
11.
J Cardiothorac Vasc Anesth ; 13(5): 579-85, 1999 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-10527228

RESUMO

OBJECTIVE: To determine the effects of thoracic epidural anesthesia on myocardial infarct size, regional myocardial blood flow (RMBF), and plasma norepinephrine in an anesthetized canine model of ischemia reperfusion injury with infarction. DESIGN: Blinded, randomized, placebo-controlled animal study. SETTING: Experiments were performed in the cardiothoracic research laboratory at Wake Forest University Baptist Medical Center. PARTICIPANTS: Anesthetized, open-chest mongrel dogs were used in these studies. METHODS: Dogs were instrumented for measurement of aortic pressure (AP) and left ventricular systolic pressure (LVSP), dP/dt, and RMBF Epidural catheters were inserted at thoracic segment T5. Three groups received epidural 0.5% bupivacaine: low-dose (n = 7; 0.3 mg/kg bolus, 0.15 mg/kg/ h), mid-dose (n = 7; 0.6 mg/kg bolus, 0.3 mg/kg/h), high-dose (n = 7; 1.2 mg/kg bolus, 0.6 mg/kg/h). The vehicle (VEH) group received epidural saline. Bolus followed by maintenance infusions began 30 minutes before the onset of ischemia (60 min) and continued through reperfusion (180 min). RESULTS: Myocardial infarct size was significantly reduced in the high-dose group versus the VEH and low-dose groups (p < 0.05). After initiation of the mid and high dose, AP, LVSP, and dP/dt decreased 7% to 16% (high vVEH; p < 0.05). VEH dogs showed a 130% increase from control in early postischemic RMBF. There was a dose-dependent attenuation in this reflow response: 72%, 31%, and 6% increase in RMBF in the low, mid, and high groups, relative to controls (p < 0.05 high v VEH). Although there was no significant difference in plasma norepinephrine, fewer surges occurred in the high-dose group. CONCLUSIONS: Thoracic epidural anesthesia reduces infarct size and postischemic hyperemia in a model of ischemia reperfusion injury.


Assuntos
Anestesia Epidural , Infarto do Miocárdio/patologia , Traumatismo por Reperfusão Miocárdica/patologia , Anestésicos Locais/administração & dosagem , Animais , Velocidade do Fluxo Sanguíneo/efeitos dos fármacos , Bupivacaína/administração & dosagem , Circulação Coronária , Creatina Quinase/sangue , Cães , Relação Dose-Resposta a Droga , Hemodinâmica/efeitos dos fármacos , Infarto do Miocárdio/etiologia , Infarto do Miocárdio/fisiopatologia , Reperfusão Miocárdica , Traumatismo por Reperfusão Miocárdica/fisiopatologia , Miocárdio/patologia , Necrose , Norepinefrina/sangue , Tórax
12.
J Appl Physiol (1985) ; 86(6): 1977-83, 1999 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-10368364

RESUMO

A time-dependent simulation model, based on the Coburn-Forster-Kane equation, was written in Advanced Continuous Simulation Language to predict carboxyhemoglobin (HbCO) formation and dissociation in F-344 rats during and after exposure to 500 parts/million CO for 1 h. Blood-gas analysis and CO-oximetry were performed on samples collected during exposure and off-gassing of CO. Volume displacement plethysmography was used to measure minute ventilation (VE) during exposure. CO diffusing capacity in the lung (DLCO) was also measured. Other model parameters measured in the animals included blood pH, total blood volume, and Hb concentration. Comparisons between model predictions using values for VE, DLCO, and the Haldane coefficient cited in the literature and predictions using measured VE, DLCO, and calculated Haldane coefficient for individual animals were made. General model predictions using values for model parameters derived from the literature agreed with published HbCO values by a factor of 0.987 but failed to simulate experimental data. On average, the general model overpredicted measured HbCO level by nearly 9%. A specific model using the means of measured variables predicted HbCO concentration within a factor of 0.993. When experimentally observed parameter fluctuations were included, the specific model predictions reflected experimental effects on HbCO formation.


Assuntos
Monóxido de Carbono/farmacologia , Carboxihemoglobina/biossíntese , Algoritmos , Animais , Análise Química do Sangue , Gasometria , Simulação por Computador , Concentração de Íons de Hidrogênio , Análise dos Mínimos Quadrados , Modelos Biológicos , Ratos , Testes de Função Respiratória
13.
Drug Chem Toxicol ; 22(1): 41-56, 1999 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-10189570

RESUMO

The relationship between lead concentration in the dry film of lead based paints applied to steel bulkheads aboard ship, the lead concentration found in the air when the paint is removed by mechanical means, and blood lead concentrations of workers involved in lead based paint removal has not been well characterized. Intuitively a direct relationship must exist but confounding factors confuse the issue. Simultaneous sampling procedures from the same paint removal operation may differ by several orders of magnitude. The process from dried film to aerosol (airborne dust) exposure, and on to dose can be separated into two major phases; (1) generation of the dust and its transport through the air to the worker and (2) uptake and dose related factors within the body. Both phases involve complex interactions and there are a number of factors within each phase that significantly affect the potential lead dose for the worker. This study attempts to clarify the mechanisms involved in the generation and transportation of the dust to the worker by evaluating the relationship of a number of key factors on particle size and lead distribution within the aerosol dust generated when lead based paint is removed by sanding. The study examined the relationship between particle size in the dust and grit size of the abrasive. It also examined the distribution of lead within selected particle sizes. The Mass Median Aerodynamic Diameter (MMAD) was used as an indicator of change in the particle size distribution. Particle size distributions were evaluated using a TSI Aerodynamic Particle Sizer, a five stage cyclone and scanning electron microscopy. Lead distribution was determined using the five stage cyclone, and personal or area samples analyzed using inductively coupled plasma (ICP). Mass concentrations were evaluated using a MIE Mass Concentration Analyzer and gravimetric analysis of filter samples collected in the breathing zone. Student's t-tests were used to evaluate changes in MMADs, mass concentrations and other indices for inter and intra-grit size samples. Correlation coefficients (Pearson's r) were used to determine the relationship between factors. Findings of the research indicated that the particle size distribution in the dust is directly related to the grit size of the abrasive (i.e. inversely related to the abrasive grit number). Particulate mass concentrations of dust varied directly with abrasive grit number. The distribution of lead did not appear to be affected by grit size of the abrasive in that the lead distribution within the particle size ranges remained homogeneous and consistent with the lead concentration in the dried film. Mass concentrations of lead in air samples varied directly with lead concentration in the bulk coating. Results of this project, coordinated with deposition modeling and bioavailability studies will be useful in the development of a model to characterize lead dose to workers based on known parameters within the work specifications.


Assuntos
Poluentes Ocupacionais do Ar/química , Chumbo/química , Exposição Ocupacional , Pintura/análise , Navios , Aerossóis , Poluentes Ocupacionais do Ar/análise , Poeira , Humanos , Chumbo/análise , Tamanho da Partícula
14.
Drug Chem Toxicol ; 22(1): 73-90, 1999 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-10189572

RESUMO

An aerosol deposition model has been written for inclusion into physiologically based pharmacokinetic (PBPK) models, allowing PBPK model based risk assessments to be performed for aerosolized materials. Previously, PBPK models could only treat inhaled gases and vapors. The deposition model employs a semi-empirical equation to describe extrathoracic deposition and employs data concerning the geometry of the thoracic conducting airways as well as that of the gas exchange regions of the lung to compute the deposited aerosol mass based on aerosol diffusion, sedimentation, and impaction. Provisions are made to allow calculations for polydisperse aerosols whose size distribution and mass vary with time. Variations in the model subject's respiration can be accommodated through selection of respiratory parameters at model startup as well as through consideration of carbon dioxide stimulation of respiration. The model is compared with other similar calculations and experimental data to validate the calculations. An example model application is presented in the form of a comparison of two inhalation atmospheres, one from an inhalation toxicity study and one from a similar atmosphere produced for fire extinguishing agent testing.


Assuntos
Aerossóis/farmacocinética , Modelos Biológicos , Farmacocinética , Sistema Respiratório/metabolismo , Administração por Inalação , Brônquios/metabolismo , Simulação por Computador , Humanos , Pulmão/metabolismo , Nasofaringe/metabolismo , Reprodutibilidade dos Testes , Distribuição Tecidual , Traqueia/metabolismo
15.
Anesthesiology ; 90(3): 727-33, 1999 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-10078673

RESUMO

BACKGROUND: Ropivacaine, 0.2%, is a new local anesthetic approved for epidural analgesia. The addition of 4 microg/ml fentanyl improves analgesia from epidural ropivacaine. Use of a lower concentration of ropivacaine-fentanyl may further improve analgesia or decrease side effects. METHODS: Thirty patients undergoing lower abdominal surgery were randomized in a double-blinded manner to receive one of three solutions: 0.2% ropivacaine-4 microg fentanyl 0.1% ropivacaine-2 microg fentanyl, or 0.05% ropivacaine-1 microg fentanyl for patient-controlled epidural analgesia after standardized combined epidural and general anesthesia. Patient-controlled epidural analgesia settings and adjustments for the three solutions were standardized to deliver equivalent drug doses. Pain scores (rest, cough, and ambulation), side effects (nausea, pruritus, sedation, motor block, hypotension, and orthostasis), and patient-controlled epidural analgesia consumption were measured for 48 h. RESULTS: All three solutions produced equivalent analgesia. Motor block was significantly more common (30 vs. 0%) and more intense with the 0.2% ropivacaine-4 microg fentanyl solution. Other side effects were equivalent between solutions and mild in severity. A significantly smaller volume of 0.2% ropivacaine-4 microg fentanyl solution was used, whereas the 0.1% ropivacaine-2 microg fentanyl group used a significantly greater amount of ropivacaine and fentanyl. CONCLUSIONS: Lesser concentrations of ropivacaine and fentanyl provide comparable analgesia with less motor block despite the use of similar amounts of ropivacaine and fentanyl. This finding suggests that concentration of local anesthetic solution at low doses is a primary determinant of motor block with patient-controlled epidural analgesia after lower abdominal surgery.


Assuntos
Amidas/administração & dosagem , Analgésicos Opioides/administração & dosagem , Anestesia Epidural , Anestésicos Locais/administração & dosagem , Fentanila/administração & dosagem , Amidas/efeitos adversos , Analgésicos Opioides/efeitos adversos , Anestesia Epidural/efeitos adversos , Anestésicos Locais/efeitos adversos , Método Duplo-Cego , Fentanila/efeitos adversos , Humanos , Dor/prevenção & controle , Náusea e Vômito Pós-Operatórios/prevenção & controle , Ropivacaina
17.
Anesthesiology ; 89(1): 24-9, 1998 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-9667290

RESUMO

UNLABELLED: BACKGROUND. Injection of local anesthetic into cerebrospinal fluid (CSF) produces anesthesia of unpredictable extent and duration. Although many factors have been identified that affect the extent of spinal anesthesia, correlations are relatively poor and the extent of spread remains unpredictable. This study was designed to determine whether variability in the volume of lumbosacral CSF among individuals is a contributing factor in the variability of spinal anesthesia. METHODS: Spinal anesthesia was administered to 10 healthy volunteers with 50 mg lidocaine in 7.5% dextrose. The technique was standardized to minimize variability in factors known to affect the distribution of spinal anesthesia. The extent of sensory anesthesia was assessed by pin-prick and by transcutaneous electrical stimulation. Motor blockade was assessed in the quadriceps and gastrocnemius muscles by force dynamometry. Duration of anesthesia was assessed by pinprick, transcutaneous electrical stimulation, and duration of motor blockade. Lumbosacral CSF volumes were calculated from low thoracic, lumbar, and sacral axial magnetic resonance images obtained at 8-mm increments. Volumes of CSF were correlated with measures of extent and duration of spinal anesthesia using the Kendall rank correlation test. RESULTS: Lumbosacral CSF volumes ranged from 42.7 to 81.1 ml. Volumes of CSF correlated with pin-prick assessments of peak sensory block height (P = 0.02) and duration of surgical anesthesia (as assessed by the duration of tolerance to transcutaneous electrical stimulation at the ankle (P < 0.05). CONCLUSIONS: Variability in lumbosacral CSF volume is the most important factor identified to date that contributes to the variability in the spread of spinal sensory anesthesia.


Assuntos
Raquianestesia , Líquido Cefalorraquidiano/fisiologia , Adulto , Pressão do Líquido Cefalorraquidiano , Feminino , Variação Genética , Humanos , Região Lombossacral , Masculino
18.
Am Fam Physician ; 56(3): 835-44, 847-50, 1997 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-9301576

RESUMO

Successful pain management requires knowing the type of surgical procedure that has been performed as well as patient characteristics that may influence the choice of analgesic. The risk of morbidity is increased in patients with certain underlying conditions such as unstable angina if they do not receive adequate postoperative analgesia. Frequent assessment of pain severity using techniques such as visual analog scales can help optimize pain control. Nonsteroidal anti-inflammatory agents provide good analgesia after most minor surgical procedures and can decrease the amount of opioid analgesics needed after more extensive procedures. Intravenous and epidurally administered opioids are useful; however, better analgesia may be achieved when local anesthetics are administered by infiltration, peripheral nerve block or continuous epidural infusion. The use of two or more analgesic techniques together produces better pain relief than a single medication or administration route. A team approach can lessen the amount of postoperative pain. Family physicians should aggressively treat postoperative pain and actively support hospital postoperative pain treatment programs.


Assuntos
Analgésicos Opioides/administração & dosagem , Anti-Inflamatórios não Esteroides/administração & dosagem , Dor Pós-Operatória/terapia , Humanos , Dor Pós-Operatória/tratamento farmacológico , Dor Pós-Operatória/fisiopatologia
19.
Anesth Analg ; 85(1): 37-43, 1997 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-9212119

RESUMO

This multicenter study compared the analgesic efficacy and side effects of ketorolac and hydrocodone-acetaminophen when administered orally after ambulatory arthroscopic or laparoscopic tubal ligation procedures. After awakening from general anesthesia, 252 patients experiencing moderate or severe postoperative pain were randomly assigned to receive one of three analgesic treatments according to a placebo-controlled, double-blind protocol. Group 1 (n = 83) received oral ketorolac 10 mg every 6 h for up to 3 days, Group 2 (n = 82) received hydrocodone 7.5 mg plus acetaminophen 750 mg every 6 h for up to 3 days, and Group 3 (n = 87) received placebo capsules followed by ketorolac 10 mg every 6 h for up to 3 days. Severity of pain was recorded using a 4-point categorical score and visual analog scale (VAS) at 0.5 h and subsequently at hourly intervals for 6 h, as well as daily for up to 3 days. Pain relief was recorded using a 5-point categorical scale at the same time points. In the patients undergoing arthroscopic surgery, both ketorolac and hydromorphone-acetaminophen provided superior pain relief compared with the placebo. Although the categorical summed pain intensity difference (SPID), VAS SPID, and total pain relief scores were higher in the ketorolac group compared with the hydrocodone-acetaminophen group, the differences were not statistically significant. In the patients undergoing laparoscopic tubal ligation surgery, the three treatment groups displayed similar responses to the study medications. However, the ketorolac group scored higher in terms of overall tolerability than the hydrocodone-acetaminophen group. In conclusion, there was no difference in the efficacy between oral ketorolac and hydrocodone-acetaminophen combination in controlling pain after outpatient arthroscopic surgery procedures. Neither oral analgesic proved to be very effective after laparoscopic tubal ligation.


Assuntos
Acetaminofen/administração & dosagem , Procedimentos Cirúrgicos Ambulatórios , Analgésicos não Narcóticos/administração & dosagem , Analgésicos Opioides/administração & dosagem , Artroscopia , Endoscopia , Hidrocodona/administração & dosagem , Esterilização Tubária , Tolmetino/análogos & derivados , Acetaminofen/efeitos adversos , Administração Oral , Adulto , Analgésicos não Narcóticos/efeitos adversos , Analgésicos Opioides/efeitos adversos , Método Duplo-Cego , Quimioterapia Combinada , Feminino , Humanos , Hidrocodona/efeitos adversos , Cetorolaco , Masculino , Medição da Dor , Dor Pós-Operatória/prevenção & controle , Tolmetino/administração & dosagem , Tolmetino/efeitos adversos
20.
Otolaryngol Head Neck Surg ; 117(1): 56-61, 1997 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-9230324

RESUMO

We report the specifics of 12 cases of severe hypertension after the intraoperative use of topical phenylephrine, submucosal epinephrine, or both. Ten of these 12 patients also developed severe pulmonary edema. Seven of the twelve were treated with beta blockers; 3 of whom suffered cardiac arrest. We propose a common mechanism: the vasoconstrictors caused systemic hypertension, increased left ventricular afterload, decreased left ventricular compliance, and decreased cardiac output. In those patients treated with beta blockers, decreased contractility and inability to increase heart rate further compromised cardiopulmonary function.


Assuntos
Agonistas alfa-Adrenérgicos/efeitos adversos , Antagonistas Adrenérgicos beta/efeitos adversos , Hipertensão/induzido quimicamente , Complicações Intraoperatórias/induzido quimicamente , Administração Intranasal , Criança , Epinefrina/efeitos adversos , Feminino , Parada Cardíaca/induzido quimicamente , Humanos , Hipertensão/tratamento farmacológico , Complicações Intraoperatórias/tratamento farmacológico , Intubação Intratraqueal , Labetalol/efeitos adversos , Masculino , Fenilefrina/efeitos adversos , Propanolaminas/efeitos adversos , Edema Pulmonar/induzido quimicamente
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