RESUMEN
Melanocytes and melanoma cells contain melanin, a complex polymer that modulates redox changes in these cells. Relative intracellular hydrogen peroxide levels measured by dichlorodihydrofluorescein are similar in the two cell types, but the levels of superoxide anion measured by dihydroethidium were markedly increased in melanoma cells. Chelator-induced oxidative stress is efficiently suppressed by melanocytes without substantial recruitment of the transcription factors NF-kappaB and AP-1 as measured by electrophoretic mobility shift assay and quantitated by densitometry or by a change in frequency of apoptosis as determined by annexin V binding. In contrast, NF-kappaB in melanoma cells is strongly recruited by changes in redox status and exhibits a correlative relationship to intracellular hydrogen peroxide (but not superoxide anion). However, the response of the NF-kappaB pathway to intracellular hydrogen peroxide is anomalous, including downregulation of p65 and IkappaBalpha RNA expression (Northern blot). Additionally, recruitment of AP-1 binding in melanoma cells was directly correlated with intracellular levels of superoxide anion (but not hydrogen peroxide). Neither the degree of NF-kappaB nor AP-1 binding in melanoma cells was related to the frequency of apoptosis. The responsiveness of NF-kappaB and AP-1 recruitment to intracellular levels of hydrogen peroxide and superoxide anion without concomitant control of apoptosis provides a general mechanism by which these cells can escape noxious injury (e.g., chemotherapy). The marked enhancement of apoptosis in melanoma cells by chelators indicates, however, that this alteration can be circumvented and offers a unique therapeutic window to explore.
Asunto(s)
Homeostasis , Melanocitos/metabolismo , Melanoma/metabolismo , Oxidación-Reducción , Anexina A5/metabolismo , Apoptosis , Quelantes/farmacología , Humanos , Peróxido de Hidrógeno/análisis , Melanocitos/química , Melanoma/química , FN-kappa B/metabolismo , Estrés Oxidativo , Especies Reactivas de Oxígeno/análisis , Superóxidos/análisis , Factor de Transcripción AP-1/metabolismo , Células Tumorales CultivadasRESUMEN
BACKGROUND: Hemodynamics often are used as surrogate end points in phase II trials of acute heart failure (HF). We reviewed the Flolan International Randomized Survival Trial (FIRST) database to identify the hemodynamic variables that best predict survival in patients with advanced HF receiving epoprostenol therapy and to determine whether hemodynamics could predict the overall effect of a drug. METHODS: The trial enrolled 471 patients with class IIIb/IV HF and ejection fraction
Asunto(s)
Antihipertensivos/uso terapéutico , Ensayos Clínicos Fase II como Asunto/estadística & datos numéricos , Epoprostenol/uso terapéutico , Insuficiencia Cardíaca/mortalidad , Insuficiencia Cardíaca/fisiopatología , Presión Esfenoidal Pulmonar , Anciano , Femenino , Insuficiencia Cardíaca/prevención & control , Hemodinámica , Humanos , Masculino , Persona de Mediana Edad , Valor Predictivo de las Pruebas , Modelos de Riesgos Proporcionales , Ensayos Clínicos Controlados Aleatorios como Asunto , Análisis de SupervivenciaRESUMEN
OBJECTIVE: To develop recommendations for positioning the second-generation pacing esophageal stethoscope for transesophageal atrial pacing in patients positioned prone (P), right lateral decubitus (RLD), and left lateral decubitus (LLD). DESIGN: Prospective; patients assigned consecutively. SETTING: Tertiary and university hospitals. PARTICIPANTS: Thirty (10 in each position group) adult patients undergoing surgery. INTERVENTIONS: The optimal depths of insertions (DOI) where pacing current threshold was minimal (THmin) were determined first when supine, then after positioning. MEASUREMENTS AND MAIN RESULTS: Transesophageal atrial pacing was successful in all patients supine and after positioning. The optimal DOI varied from 2 cm less deep to 4 cm deeper in positioned patients compared with supine patients. Patients positioned P required equal or up to 8 mA greater current outputs to achieve transesophageal atrial pacing; LLD and RLD patients may require up to 8 mA greater or lesser current compared with supine patients. CONCLUSION: Transesophageal atrial pacing can be used safely and effectively in patients positioned P, RLD, and LLD. Recommendations are presented for positioning the pacing esophageal stethoscope. Emphasis is given to using the lowest DOIs and smallest currents to reduce the chance of transesophageal ventricular pacing.
Asunto(s)
Estimulación Cardíaca Artificial , Postura/fisiología , Posición Prona/fisiología , Adolescente , Adulto , Anciano , Anestesia por Inhalación , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estudios ProspectivosRESUMEN
BACKGROUND: Earlier, rapid evaluation in chest pain units may make patient care more efficient. A multimarker strategy (MMS) testing for several markers of myocardial necrosis with different time-to-positivity profiles also may offer clinical advantages. METHODS AND RESULTS: We prospectively compared bedside quantitative multimarker testing versus local laboratory results (LL) in 1005 patients in 6 chest pain units. Myoglobin, creatine kinase-MB, and troponin I were measured at 0, 3, 6, 9 to 12, and 16 to 24 hours after admission. Two MMS were defined: MMS-1 (all 3 markers) and MMS-2 (creatine kinase-MB and troponin I only). The primary assessment was to relate marker status with 30-day death or infarction. More patients were positive by 24 hours with MMS than with LL (MMS-1, 23.9%; MMS-2, 18.8%; LL, 8.8%; P=0.001, all comparisons), and they became positive sooner with MMS-1 (2.5 hours, P=0.023 versus LL) versus MMS-2 (2.8 hours, P=0.026 versus LL) or LL (3.4 hours). The relation between baseline MMS status and 30-day death or infarction was stronger (MMS-1: positive, 18.8% event rate versus negative, 3.0%, P=0.001; MMS-2: 21.9% versus 3.2%, P=0.001) than that for LL (13.6% versus 5.5%, P=0.038). MMS-1 discriminated 30-day death better (positive, 2.0% versus negative, 0.0%, P=0.007) than MMS-2 (positive, 1.8% versus negative, 0.2%; P=0.055) or LL (positive, 0.0% versus negative, 0.5%; P=1.000). CONCLUSIONS: Rapid multimarker analysis identifies positive patients earlier and provides better risk stratification for mortality than a local laboratory-based, single-marker approach.
Asunto(s)
Dolor en el Pecho/sangre , Isquemia Miocárdica/diagnóstico , Adolescente , Adulto , Biomarcadores/sangre , Dolor en el Pecho/etiología , Creatina Quinasa/sangre , Humanos , Persona de Mediana Edad , Isquemia Miocárdica/complicaciones , Mioglobina/sangre , Valor Predictivo de las Pruebas , Factores de Riesgo , Análisis de Supervivencia , Factores de Tiempo , Troponina I/sangreRESUMEN
Metastatic melanomas are typically resistant to radiation and chemotherapy. The underlying basis for this phenomenon may result in part from defects in apoptotic pathways. Nuclear factor kappa B (NFkappaB) has been shown to control apoptosis in many cell types and normally functions as an immediate stress response mechanism that is rigorously controlled by multiple inhibitory complexes. We have previously shown that NFkappaB binding is elevated in metastatic melanoma cells relative to normal melanocytes. In the current study, Western blot analysis showed that, compared with normal melanocytes, melanoma cell lines have higher nuclear levels of the NFkappaB subunits p50 (7-fold) and RelA (5-10-fold). In response to tumor necrosis factor-alpha (TNFalpha), both melanocytes and melanoma cells showed increased nuclear p50 and RelA levels, but levels in melanoma cells remained higher than in melanocytes. We also found that melanoma cells expressed higher cytoplasmic levels of RelA, p105/p50 and the inhibitory protein, inhibitor of kappa B alpha (IkappaBalpha) than melanocytes. To directly test whether RelA expression has an impact on melanoma cell survival, we used antisense RelA phosphorothioate oligonucleotides and found that melanoma cell viability was significantly decreased compared with untreated or control cultures. The constitutive activation of NFkappaB in metastatic melanoma cell cultures may, therefore, support an inappropriate cell survival pathway that can be therapeutically manipulated.
Asunto(s)
Proteínas de Unión al ADN/metabolismo , Proteínas I-kappa B , Melanocitos/metabolismo , Melanoma/metabolismo , FN-kappa B/metabolismo , Metástasis de la Neoplasia/fisiopatología , Células Tumorales Cultivadas/metabolismo , Rayos Ultravioleta , Transporte Activo de Núcleo Celular/efectos de los fármacos , Transporte Activo de Núcleo Celular/fisiología , Transporte Activo de Núcleo Celular/efectos de la radiación , Sitios de Unión/efectos de los fármacos , Sitios de Unión/fisiología , Núcleo Celular/efectos de los fármacos , Núcleo Celular/metabolismo , Supervivencia Celular/efectos de los fármacos , Supervivencia Celular/fisiología , Citoplasma/metabolismo , Citoplasma/efectos de la radiación , Proteínas de Unión al ADN/genética , Proteínas de Unión al ADN/efectos de la radiación , Humanos , Recién Nacido , Masculino , Melanocitos/efectos de los fármacos , Melanocitos/efectos de la radiación , Melanoma/tratamiento farmacológico , Melanoma/radioterapia , Inhibidor NF-kappaB alfa , FN-kappa B/genética , FN-kappa B/efectos de la radiación , Subunidad p50 de NF-kappa B , Metástasis de la Neoplasia/tratamiento farmacológico , Metástasis de la Neoplasia/radioterapia , ARN Mensajero/metabolismo , ARN Mensajero/efectos de la radiación , Factor de Transcripción ReIA , Células Tumorales Cultivadas/efectos de los fármacos , Células Tumorales Cultivadas/efectos de la radiación , Factor de Necrosis Tumoral alfa/farmacología , Regulación hacia Arriba/genéticaRESUMEN
OBJECTIVE: To evaluate clinical characteristics and outcomes of patients with advanced heart failure receiving intravenous continuous dobutamine in the FIRST Trial (Flolan International Randomized Survival Trial). METHODS: Four hundred seventy-one patients with class IIIb to IV heart failure who were enrolled in the FIRST trial were included. Eighty patients treated with dobutamine at FIRST randomization were compared with 391 patients not treated with dobutamine at randomization. The occurrence of worsening heart failure, need for vasoactive medications, resuscitated cardiac arrest, myocardial infarction, and total mortality were compared between the 2 groups. RESULTS: The dobutamine group had a higher occurrence of first event (85.3% vs 64. 5%; P =.0006) and a higher mortality rate (70.5% vs 37.1%; P =.0001) compared with the no dobutamine group. Intravenous continuous dobutamine was an independent risk factor for death after adjusting for baseline differences. CONCLUSIONS: Dobutamine use at the time of randomization was associated with a higher 6-month mortality rate. This effect persisted after adjustment for baseline differences. This analysis challenges the concept that continuous intravenous dobutamine is beneficial to advanced heart failure patients with respect to survival.
Asunto(s)
Cardiotónicos/uso terapéutico , Dobutamina/uso terapéutico , Insuficiencia Cardíaca/tratamiento farmacológico , Insuficiencia Cardíaca/mortalidad , Anciano , Cardiotónicos/administración & dosificación , Dobutamina/administración & dosificación , Femenino , Humanos , Infusiones Intravenosas , Masculino , Persona de Mediana Edad , Riesgo , Índice de Severidad de la Enfermedad , Análisis de Supervivencia , Resultado del TratamientoRESUMEN
The biological basis for the general pharmacological resistance of human melanoma is unknown. A unique biochemical feature of the melanocyte is the synthesis of melanin, which leads to the generation of hydrogen peroxide and the consumption of reduced glutathione. This activity produces a state of chronic oxidative stress in these cells. We demonstrated previously that the expression of the c-jun family was dysregulated in metastatic melanoma cells compared with normal human melanocytes (D. T. Yamanishi et al., J. Invest. Dermatol., 97: 349-353, 1991). In the current investigation, we measured the levels of two major redox response transcription factors, nuclear factor-kappaB (NF-kappaB) and activator protein-1, in metastatic melanoma cells and normal melanocytes and their response to oxidative stress. The basal DNA-binding activity of NF-kappaB as measured by the electrophoretic mobility shift assay in metastatic melanoma cells was increased 4-fold compared with that of normal melanocytes. This level of binding was paralleled by a 1.5- to 4-fold increase in the expression of p50 (NF-kappaB1), p65 (Rel-A), and IkappaB-alpha as measured by Northern blot analysis. In contrast, the expression of p75 (c-rel) was markedly decreased (60%) in melanoma cells compared with normal melanocytes. Following oxidative stress produced by enzyme-generated H2O2, free H2O2, or incubation with buthionine sulfoximine, NF-kappaB binding activity increased 1.5- to 2.5-fold in melanoma cells (buthionine sulfoximine > H2O2), but only slightly in normal melanocytes. In contrast, activator protein-1 binding activity was unaffected or increased in normal melanocytes in response to oxidative stress, but was either unaffected or decreased in melanoma cells. These results suggest that the redox regulation of melanoma cells at the molecular level is fundamentally different from normal melanocytes and may offer a unique avenue for preventive or therapeutic intervention as well as new insights into the pathogenesis of melanocyte transformation.
Asunto(s)
Proteínas I-kappa B , Melanoma/genética , FN-kappa B/metabolismo , Proteínas de Neoplasias/metabolismo , Isoformas de Proteínas/metabolismo , Butionina Sulfoximina/farmacología , Proteínas de Unión al ADN/biosíntesis , Proteínas de Unión al ADN/genética , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Humanos , Peróxido de Hidrógeno/farmacología , Melanocitos/efectos de los fármacos , Melanocitos/metabolismo , Melanoma/metabolismo , Melanoma/patología , Inhibidor NF-kappaB alfa , Metástasis de la Neoplasia , Oxidación-Reducción , Estrés Oxidativo , Factor de Transcripción AP-1/metabolismo , Células Tumorales Cultivadas/efectos de los fármacos , Células Tumorales Cultivadas/metabolismoRESUMEN
AIMS: To evaluate the clinical characteristics and long-term outcomes of advanced heart failure patients (NYHA Class IIIb-IV) receiving beta-blocker therapy vs. those patients not receiving beta-blockers at randomization in the FIRST trial, a randomized, double-blind, placebo-controlled trial of epoprostenol vs. usual care in advanced heart failure. METHODS AND RESULTS: The patient population consisted of 471 patients enrolled in FIRST with Class IIIb-IV heart failure, left ventricular ejection fraction (LVEF) of <30%, advanced hemodynamic abnormalities, and standard pharmacologic treatment of ACE-inhibitor, diuretics, and/or digoxin. The study cohort consisted of 448 patients not receiving beta-blockers and 23 patients receiving beta-blockers at randomization for the FIRST trial. Patients in the beta-blocker group had decreased rates of any clinical event (P = 0.03), worsening heart failure (P = 0.001), and death or worsening heart failure (P = 0.0008) than patients not receiving beta-blockers. After adjusting for prognostically important variables, the favorable effect of beta-blockers on worsening heart failure (P = 0.02) and death or worsening heart failure (P = 0.02) persisted. CONCLUSION: Patients with advanced heart failure who receive beta-blocker therapy have a lower rate of hospitalization and are less likely to experience worsening heart failure or death at 6 months than patients who are not treated with beta-blockers. These observational data contribute to the growing body of data demonstrating a favorable effect of beta-blockers on clinical outcomes in heart failure.
Asunto(s)
Antagonistas Adrenérgicos beta/uso terapéutico , Insuficiencia Cardíaca/tratamiento farmacológico , Anciano , Epoprostenol/uso terapéutico , Femenino , Insuficiencia Cardíaca/mortalidad , Insuficiencia Cardíaca/fisiopatología , Humanos , Masculino , Metoprolol/uso terapéutico , Persona de Mediana Edad , Inhibidores de Agregación Plaquetaria/uso terapéutico , Ensayos Clínicos Controlados Aleatorios como Asunto , Análisis de Supervivencia , Resultado del TratamientoRESUMEN
OBJECTIVE: This study evaluated the effect of a heparin-bonded pulmonary artery catheter (PAC) on the activated coagulation time (ACT). DESIGN: A prospective, controlled comparison. SETTING: A tertiary care university hospital. PARTICIPANTS: Adult cardiac surgery patients. INTERVENTIONS: Celite ACTs were measured from arterial and central venous blood samples before and after the insertion of a heparin-bonded PAC. Thromboelastograms were also obtained from central venous blood samples before and 2 minutes after PAC insertion. MEASUREMENTS AND MAIN RESULTS: There was no significant difference between the sample sites before PAC insertion. After PAC insertion, the central venous ACTs were significantly increased compared with the corresponding arterial measurements at 2, 5, 10, and 20 minutes (p < 0.005, analysis of variance [ANOVA] for repeated measures, Fisher's protected least significant difference [PLSD]). The 2-minute post-PAC reaction time from the central venous blood sample was greater than 60 minutes in all cases. CONCLUSION: The heparin-bonded PAC was associated with a localized, time-dependent alteration in the ACT. Whenever possible, blood samples for baseline ACT measurements should be obtained from an arterial catheter to minimize the anticoagulant effects from the PAC.
Asunto(s)
Anticoagulantes/farmacología , Heparina/farmacología , Tiempo de Coagulación de la Sangre Total , Adulto , Cateterismo de Swan-Ganz , Humanos , Estudios ProspectivosRESUMEN
OBJECTIVE: To determine how hemoglobin (Hb), platelet, and serotonin concentrations change during cardiopulmonary bypass (CPB) in sequestered blood from the pulmonary artery compared with circulating systemic blood; and to determine the correlation between platelet and serotonin variability at the two sites and clinical outcome measurements related to hemodynamics and blood loss. DESIGN: A prospective clinical study. SETTING: A university hospital. PARTICIPANTS: Twenty patients undergoing elective aortocoronary bypass. INTERVENTIONS: Measurements of Hb, platelet, and serotonin concentrations were performed before, during, and after CPB on paired blood samples from the pulmonary artery and the radial artery. Hemodynamic measurements were recorded before and after CPB and chest tube drainage was recorded postoperatively. MEASUREMENTS AND MAIN RESULTS: The Hb, platelet, and serotonin concentrations were all significantly different between radial artery and pulmonary artery samples at the different measurement times (p < 0.001, analysis of variance [ANOVA] for repeated measures). Hb, platelet, and serotonin concentrations were all significantly increased in the pulmonary artery at the time of aortic cross-clamping compared with the corresponding radial artery blood samples (p < 0.0005, ANOVA). During the period of ischemic arrest, Hb was unchanged in the pulmonary artery and remained significantly increased compared with systemic blood (p < 0.0005, ANOVA). Serotonin concentrations in both systemic and sequestered pulmonary artery blood had significant correlation with cardiac index (CI), right ventricular ejection fraction (REF), and systemic vascular resistance index (SVRI; p < or = 0.006, least squares analysis). Postoperative chest tube drainage most closely correlated with the platelet counts measured in both the radial and pulmonary arteries at the start of CPB (p < 0.05, least squares analysis). CONCLUSION: During CPB, there were significant differences in Hb, platelet, and serotonin concentrations in sequestered pulmonary artery blood compared with circulating systemic blood. The initial differences and subsequent changes were most likely attributable to decreased hemodilution and a different pattern of platelet activation in the pulmonary artery blood compared with the systemic blood. Despite the hematologic differences, serotonin concentration and platelet counts in the pulmonary artery blood had significant correlation to indices of cardiac function and postoperative chest tube drainage, respectively. Platelet and serotonin changes in sequestered pulmonary artery blood were also associated with some of the adverse consequences of CPB.
Asunto(s)
Puente Cardiopulmonar , Hemoglobinas/análisis , Recuento de Plaquetas , Serotonina/sangre , Análisis de Varianza , Pérdida de Sangre Quirúrgica , Gasto Cardíaco/fisiología , Tubos Torácicos , Puente de Arteria Coronaria , Drenaje , Procedimientos Quirúrgicos Electivos , Femenino , Paro Cardíaco Inducido , Hemodilución , Hemodinámica , Humanos , Análisis de los Mínimos Cuadrados , Masculino , Persona de Mediana Edad , Activación Plaquetaria/fisiología , Estudios Prospectivos , Arteria Pulmonar , Arteria Radial , Volumen Sistólico/fisiología , Factores de Tiempo , Resultado del Tratamiento , Resistencia Vascular/fisiología , Función Ventricular Derecha/fisiologíaRESUMEN
OBJECTIVE: This study evaluated various substances that could be used to calibrate the Thrombelastograph. DESIGN: Prospective, controlled comparison. SETTING: Operating room laboratory at a tertiary care university hospital. PARTICIPANTS: None. INTERVENTIONS: Six substances commonly available in the operating room setting (ointments, creams, and gels) were analyzed by thromboelastography for 3 minutes. Sixty measurements were made for each substance. MEASUREMENTS AND MAIN RESULTS: Thromboelastographic analysis of the ointments and cream preparations had an amplitude variability that exceeded 10 mm within the 3-minute recording period. The conductive gel had the most reproducible thromboelastography tracing with a mean amplitude of 62.5 +/- 1.1 mm (analysis of variance, p < 0.0005). There was a significant correlation between the reported viscosity of the three gels and the deflection amplitude (linear regression, R2 = 0.97; p < 0.0001). CONCLUSION: Conductive gel is a useful substance for quickly checking the functional status of the Thrombelastograph at an operational stage. Calibration of the Thrombelastograph using a gel of known viscosity is clinically relevant and may be more practical than testing with thromboelastographic-defined normal and abnormal blood analogs.
Asunto(s)
Tromboelastografía/normas , Calibración , Geles , Pomadas , Estudios Prospectivos , ViscosidadRESUMEN
OBJECTIVE: This study evaluated platelet effects on thromboelastography to determine how morphologically abnormal platelets affected native whole blood analysis. DESIGN: Prospective, controlled comparison. SETTING: Tertiary care university hospital. PARTICIPANTS: Volunteer cardiac surgery patients. INTERVENTIONS: Fresh platelets were obtained from volunteers and were either treated normally or cryodisrupted with liquid nitrogen. Fresh platelets, liquid nitrogen-treated platelets, or an equivalent quantity of the patient's blood were added to whole blood samples obtained from cardiac surgery patients before heparinization. Thromboelastographic parameters sensitive to platelet effects were measured in each of the three groups. MEASUREMENTS AND MAIN RESULTS: Maximum amplitude and alpha-angle significantly increased in the two groups receiving added platelets. There were no differences between the fresh platelet and the liquid nitrogen-treated platelet groups (Student's paired t-test). The R-time decreased significantly in both platelet-treated groups compared with the group that did not receive additional platelets. CONCLUSIONS: Viscoelastic changes in whole blood coagulation after the addition of platelet concentrates are not dependent on morphologically intact or functionally normal platelets. This in vitro study predicts that transfusion of poorly preserved platelet concentrates as well as fresh platelets would increase clot strength on thromboelastography if the recipient's blood were tested immediately after administration.
Asunto(s)
Plaquetas/fisiología , Tromboelastografía , Coagulación Sanguínea , Humanos , Transfusión de Plaquetas , Estudios ProspectivosRESUMEN
BACKGROUND: The apparent benefit of magnesium in acute myocardial infarction, and the persistently poor outcome after cardiac arrest, have led to use of magnesium in cardiopulmonary resuscitation. Because few data on its use in cardiac arrest were available, we undertook a randomised placebo-controlled trial (MAGIC trial). METHODS: Patients treated for cardiac arrest by the Duke Hospital code team were randomly assigned intravenous magnesium (2 g [8 mmoles] bolus, followed by 8 g [32 mmoles] over 24 h; 76 patients) or placebo (80 patients). Only patients in intensive care or general wards were eligible; those whose cardiac arrest occurred in emergency, operating, or recovery rooms were excluded. The primary endpoint was return of spontaneous circulation, defined as attainment of any measurable blood pressure or palpable pulse for at least 1 h after cardiac arrest. The secondary endpoints were survival to 24 h, survival to hospital discharge, and neurological outcome. Analysis was by intention to treat. FINDINGS: There were no significant differences between the magnesium and placebo groups in the proportion with return of spontaneous circulation (41 [54%] vs 48 [60%], p = 0.44), survival to 24 h (33 [43%] vs 40 [50%], p = 0.41), survival to hospital discharge (16 [21%] vs 17 [21%], p = 0.98), or Glasgow coma score (median 15 in both). INTERPRETATION: Empirical magnesium supplementation did not improve the rate of successful resuscitation, survival to 24 h, or survival to hospital discharge overall or in any subpopulation of patients with in-hospital cardiac arrest.
Asunto(s)
Paro Cardíaco/tratamiento farmacológico , Sulfato de Magnesio/uso terapéutico , Anciano , Reanimación Cardiopulmonar , Método Doble Ciego , Femenino , Paro Cardíaco/mortalidad , Paro Cardíaco/terapia , Hospitalización , Humanos , Infusiones Intravenosas , Sulfato de Magnesio/administración & dosificación , Masculino , Persona de Mediana Edad , Tasa de SupervivenciaRESUMEN
This trial evaluated the effects of epoprostenol on patients with severe left ventricular failure. Patients with class IIIB/IV congestive heart failure and decreased left ventricular ejection fraction were eligible for enrollment if angiography documented severely compromised hemodynamics while the patient was receiving a regimen of digoxin, diuretics, and an angiotensin-converting enzyme inhibitor. We randomly assigned 471 patients to epoprostenol infusion or standard care. The primary end point was survival; secondary end points were clinical events, congestive heart failure symptoms, distance walked in 6 minutes, and quality-of-life measures. The median dose of epoprostenol was 4.0 ng/kg/min, resulting in a significant increase in cardiac index (1.81 to 2.61 L/min/m2), a decrease in pulmonary capillary wedge pressure (24.5 to 20.0 mm Hg), and a decrease in systemic vascular resistance (20.76 to 12.33 units). The trial was terminated early because of a strong trend toward decreased survival in the patients treated with epoprostenol. Chronic intravenous epoprostenol therapy is not associated with improvement in distance walked, quality of life, or morbid events and is associated with an increased risk of death.
Asunto(s)
Antihipertensivos/uso terapéutico , Epoprostenol/uso terapéutico , Insuficiencia Cardíaca/tratamiento farmacológico , Anciano , Angiografía , Inhibidores de la Enzima Convertidora de Angiotensina/uso terapéutico , Antihipertensivos/administración & dosificación , Gasto Cardíaco/efectos de los fármacos , Cardiotónicos/uso terapéutico , Causas de Muerte , Digoxina/uso terapéutico , Diuréticos/uso terapéutico , Epoprostenol/administración & dosificación , Tolerancia al Ejercicio/efectos de los fármacos , Femenino , Humanos , Infusiones Intravenosas , Masculino , Persona de Mediana Edad , Modelos de Riesgos Proporcionales , Presión Esfenoidal Pulmonar/efectos de los fármacos , Calidad de Vida , Factores de Riesgo , Volumen Sistólico/efectos de los fármacos , Tasa de Supervivencia , Resistencia Vascular/efectos de los fármacos , Disfunción Ventricular Izquierda/tratamiento farmacológico , Caminata/fisiologíaRESUMEN
The purpose of this study was to compare the accuracy of conductivity, adjusted conductivity, photometric, and centrifugation methods of measuring or estimating hemoglobin (Hb) with Coulter measured HB as the reference. These bedside methods were studied in 25 cardiac surgery patients during euvolemia and hemodilution and after salvaged autologous red blood cell transfusion. In vivo patient blood samples were obtained before induction, at the start of cardiopulmonary bypass (CPB), after CPB, and after blood transfusion. In 10 patients, blood was sampled in vitro from units of processed blood. Hb values were determined using conductivity by Stat-Crit, adjusted conductivity by Nova Stat Profile 9, bedside photometry by HemoCue, and centrifugation methods. The calculated bias values of Coulter test method Hb (mean +/- SD) for in vivo patient blood samples (n = 90) were: Stat-Crit = 0.6 +/- 0.8 g/dL; Nova Stat Profile 9 = -0.7 +/- 0.4 g/dL; HemoCue = -0.1 +/- 0.2 g/dL; and centrifuge = 0.1 +/- 0.5 g/dL (P < 0.0001). Hb bias values (g/dL) for in vitro samples (n = 10) obtained from processed blood were Stat-Crit = 5.1 +/- 0.6; Nova Stat Profile 9 = 3.0 +2- 0.6; HemoCue = 0.4 +/- 0.4; and centrifuge = 0.6 +/- 0.3 (P < 0.0001). Hb assessment by different test methods may be significantly affected during hemodilution and after blood transfusion. In vitro conditions exaggerated the inaccuracy of conductivity and adjusted conductivity Hb estimates. The rank order of closest approximation to the Coulter measurement for all in vivo blood samples was provided by bedside photometry, followed by centrifugation, adjusted conductivity, and uncorrected conductivity methods.
Asunto(s)
Procedimientos Quirúrgicos Cardíacos , Hemoglobinas/análisis , Monitoreo Intraoperatorio , Análisis de Varianza , Sesgo , Proteínas Sanguíneas/análisis , Transfusión Sanguínea , Transfusión de Sangre Autóloga , Volumen Sanguíneo , Puente Cardiopulmonar , Centrifugación , Cloruros/sangre , Conductividad Eléctrica , Transfusión de Eritrocitos , Fluidoterapia , Hemodilución , Humanos , Soluciones Isotónicas/uso terapéutico , Modelos Lineales , Fotometría , Sodio/sangreAsunto(s)
Periodo de Recuperación de la Anestesia , Puente de Arteria Coronaria , Lorazepam/farmacología , Midazolam/farmacología , Factores de Edad , Anciano , Concienciación/efectos de los fármacos , Femenino , Humanos , Cuidados Intraoperatorios , Intubación Intratraqueal , Lorazepam/administración & dosificación , Masculino , Midazolam/administración & dosificación , Persona de Mediana Edad , Morfina/administración & dosificación , Dolor Postoperatorio/prevención & control , Placebos , Método Simple Ciego , Volumen Sistólico , Disfunción Ventricular/fisiopatologíaRESUMEN
The action of 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) on transcription and steady-state mRNA levels, protein expression, and enzymatic activity of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) in cultured human keratinocytes was examined. GAPDH transcription increased as a function of time of exposure to TCDD, reaching a maximum of 23-fold after 8 days. Northern blot analysis showed a 4-fold increase in mRNA after 8 days exposure. Protein levels were increased 4-fold, and dehydrogenase activity by 5-fold, under the same exposure conditions. GAPDH is commonly thought of as a constitutive housekeeping gene and is often used as a loading control for northern blot analysis. Our data suggest that caution should be used when using GAPDH as an RNA control, especially in studies examining cell proliferation and carcinogenesis.
Asunto(s)
Regulación Enzimológica de la Expresión Génica/efectos de los fármacos , Gliceraldehído-3-Fosfato Deshidrogenasas/biosíntesis , Queratinocitos/enzimología , Dibenzodioxinas Policloradas/farmacología , Transcripción Genética/efectos de los fármacos , Northern Blotting , Western Blotting , Núcleo Celular/metabolismo , Células Cultivadas , Gliceraldehído-3-Fosfato Deshidrogenasas/análisis , Humanos , Queratinocitos/efectos de los fármacos , Cinética , ARN Mensajero/biosíntesis , ARN Mensajero/metabolismo , Factores de TiempoRESUMEN
The authors report two longitudinal studies of new college roommates (Ns = 69 and 95 pairs). In both studies, targets' initial self-views predicted changes in perceivers' appraisals of them, and perceivers' initial appraisals predicted changes in targets' self-views, although few dyads displayed both effects. The perceiver-driven and target-driven effects occurred when appraisals and self-views were negative as well as positive. Implications for self-verification theory and symbolic interactionism are discussed, and a less restrictive model of how appraisals influence self-views is proposed.
Asunto(s)
Ego , Relaciones Interpersonales , Negociación , Femenino , Humanos , Estudios Longitudinales , MasculinoRESUMEN
OBJECTIVE: Our objective was to compare the effect of protein and electrolyte changes associated with hemodilution on the accuracy of photometric and conductivity hemoglobin determination methods. METHODS: Blood samples from 10 patients with normal preoperative serum electrolytes and total protein levels were studied. From an indwelling arterial line, 20 ml of blood were removed; hemoglobin values were measured pre-(Baseline) and postdilution by Coulter counter, conductivity, and photometric methods. Blood samples were diluted by placing 4 ml of blood into three test tubes, and adding 1 ml of either 25% albumin, 0.9% sodium chloride, or 5% dextrose in water. RESULTS: Blood sample dilution resulted in a reported conductivity hemoglobin that was significantly different from the Coulter value (p = 0.0004) when 25% albumin, 0.9% sodium chloride, and 5% dextrose in water solution was used. Using the same dilutions, the photometric method accurately reflected Coulter hemoglobin values. The correlation between photometric and Coulter hemoglobin measurements was R2 = 0.97, p = 0.0001. Correcting the conductivity hemoglobin values for changes in total protein, chloride and sodium significantly improved correlation with Coulter hemoglobin (R2 of uncorrected versus corrected = 0.37 and 0.72; p = 0.0001). CONCLUSIONS: In the range of electrolyte and protein concentrations found in this study, the photometric method of hemoglobin assessment was more accurate than either corrected or uncorrected conductivity hemoglobin determinations, as compared to Coulter-based measurements.
Asunto(s)
Proteínas Sanguíneas/análisis , Electrólitos/sangre , Hemoglobinas/análisis , Cloruros/sangre , Conductividad Eléctrica , Pruebas Hematológicas/instrumentación , Humanos , Fotometría , Sodio/sangreRESUMEN
We studied the comparative vascular effects of midazolam and lorazepam in 52 patients undergoing elective cardiac surgery procedures. After administration of fentanyl, 100 micrograms/kg intravenously, the patients were randomized to receive either midazolam 0.1 mg/kg (M high), midazolam 0.05 mg/kg (M low), lorazepam 0.1 mg/kg (L high), lorazepam 0.05 mg/kg (L low), or placebo during cardiopulmonary bypass (CPB). Compared to the placebo and L-low groups, the high-dose midazolam group had more effect on systemic vascular resistance (SVR) starting at 5 min after study drug administration (P < 0.02). M high and L high required increased quantities of phenylephrine administered to maintain the mean arterial pressure (MAP) at > 50 mm Hg after rewarming and removal of the aortic cross-clamp (P < 0.03). In the first 12 h of the postoperative period, the M-high group required phenylephrine (PHE) infusion for hypotension associated with decreased SVR more often than placebo (8/10 vs 1/11 patients, P < 0.008, chi 2). In conclusion, midazolam more effectively attenuated the increase in SVR that occurred during CPB than patients receiving either placebo or lorazepam. The hemodynamic effects from a single dose of 0.1 mg/kg midazolam administered at the start of CPB may persist into the postoperative period.