RESUMEN
Lead is recognized worldwide as a poisonous metal. Thus, the determination of this element is often required in environmental, biological, food and geological samples. However, these analyses are difficult because such samples contain relatively low concentrations of lead, which fall below the detection limit of conventional analytical techniques such as flame atomic absorption spectrometry and inductively coupled plasma optical emission spectrometry. Several preconcentration procedures to determine lead have therefore been devised, involving separation techniques such as liquid-liquid extraction, solid phase extraction, coprecipitation and cloud point extraction. Citing 160 references, this paper offers a critical review of preconcentration procedures for determining lead using spectroanalytical techniques.
RESUMEN
BACKGROUND: The use of left ventricular assist devices (LVADs) as bridge to transplantation is now accepted as a standard of care for a subset of end-stage heart failure patients. Our interim experience with both pneumatically and electrically powered ThermoCardiosystems LVADs is presented to outline the benefits and limitations of device support as well as discuss its potential role as bridge to recovery and as destination therapy. METHODS AND RESULTS: Detailed records were kept prospectively for all patients undergoing LVAD insertion. One hundred LVADs were inserted over 7 years into 95 patients, with an overall survival rate of 75% and a transplantation rate of 70%. Four patients underwent device explant for recovered myocardial function. Three patients received LVADs as destination therapy in the ongoing REMATCH (Randomized Evaluation of Mechanical Assist Treatment for Congestive Heart failure) trial. Overall mean patient age was 51 years, and mean duration of support was 108 days. There were 25 device-related infections including the drive line, device pocket, and blood-contacting surfaces. Cerebral vascular accidents and other embolic events occurred in 7 patients with six deaths. There were four device malfunctions and nine graft-related hemorrhages, resulting in six reoperations and three deaths. CONCLUSIONS: The use of long-term implantable LVADs will likely not be limited to bridge to transplantation. The REMATCH trial has commenced to study the role LVADs may have as an alternative to medical management. Furthermore, as the issues of myocardial recovery are examined, the "bridge to recovery" may be an important additional role for these assist devices.
Asunto(s)
Insuficiencia Cardíaca/cirugía , Corazón Auxiliar , Causas de Muerte , Falla de Equipo , Femenino , Estudios de Seguimiento , Insuficiencia Cardíaca/etiología , Insuficiencia Cardíaca/mortalidad , Trasplante de Corazón , Mortalidad Hospitalaria , Hospitales Universitarios , Humanos , Cuidados a Largo Plazo , Masculino , Persona de Mediana Edad , Ciudad de Nueva York , Tasa de SupervivenciaRESUMEN
BACKGROUND: The pharmacological effects of infusion of human brain natriuretic peptide (hBNP) in patients with severe congestive heart failure have not been characterized previously. METHODS AND RESULTS: Twenty patients with severe congestive heart failure were randomized in a double-blind, placebo-controlled, crossover trial to receive incremental 90-minute infusions of hBNP (0.003, 0.01, 0.03, and 0.1 microgram/kg per minute) or placebo on 2 consecutive days. At the highest completed dose of the hBNP, mean pulmonary artery pressure decreased from 38.3 +/- 1.6 to 25.9 +/- 1.7 mm Hg; mean pulmonary capillary wedge pressure decreased from 25.1 +/- 1.1 to 13.2 +/- 1.3 mm Hg; mean right atrial pressure decreased from 10.9 +/- 1 to 4.8 +/- 1.0 mm Hg; mean arterial pressure decreased from 85.2 +/- 2.0 to 74.9 +/- 1.7 mm Hg; and cardiac index increased from 2.0 +/- 0.1 to 2.5 +/- 0.1 L/min per square meter (all P < .01 versus placebo). Urine volume and urine sodium excretion increased significantly during hBNP infusion when compared with placebo infusion (90 +/- 38 versus 67 +/- 27 mL/h and 2.6 +/- 2.4 versus 1.4 +/- 1.2 mEq/h, respectively, both P < .05 versus placebo), whereas creatinine clearance and urinary potassium excretion did not change. CONCLUSIONS: Infusion of incremental doses of hBNP is associated with favorable hemodynamic and natriuretic effects in patients with severe congestive heart failure.
Asunto(s)
Insuficiencia Cardíaca/fisiopatología , Hemodinámica/efectos de los fármacos , Riñón/fisiopatología , Proteínas del Tejido Nervioso/farmacología , Presión Sanguínea/efectos de los fármacos , Creatinina/metabolismo , GMP Cíclico/sangre , Método Doble Ciego , Femenino , Frecuencia Cardíaca/efectos de los fármacos , Humanos , Infusiones Intravenosas , Riñón/efectos de los fármacos , Masculino , Persona de Mediana Edad , Péptido Natriurético Encefálico , Proteínas del Tejido Nervioso/administración & dosificación , Proteínas del Tejido Nervioso/sangre , Placebos , Potasio/orina , Arteria Pulmonar/efectos de los fármacos , Arteria Pulmonar/fisiopatología , Presión Esfenoidal Pulmonar/efectos de los fármacos , Sodio/orina , Volumen Sistólico/efectos de los fármacos , Resistencia Vascular/efectos de los fármacosRESUMEN
A 24-year-old woman noted erythematous tender nodules on her extremities and temporal areas while being treated for Campylobacter-positive colitis. Histologic examination showed groups of inflammatory cells in the subcutaneous tissue and dermis around pilosebaceous follicles and sweat glands. The diagnosis of nonspecific, chronic dermatitis and panniculitis was made. The cutaneous lesions improved with the administration of tetracycline, Azulfidine, and adrenocorticotropic hormone, after which a negative culture for Campylobacter was obtained. Campylobacter colitis may stimulate ulcerative colitis.