Determination of organochlorine and organophosphate pesticide residues in fruits, vegetables and sediments.

A method is described for the determination of organochlorine and organophosphate pesticide residues in fruits, vegetables and sediments. The concentrated solvent extract was sealed in a polymeric membrane tube, dialysed in cyclohexane and the solvent replaced with hexane. The organophosphates were analysed on a specific thermionic detector without further clean-up. For the organochlorine pesticides the extract was eluted through 3 g of alumina and analysed on GC/ECD. The clean-up for sediment extract was carried out on a 10 g alumina column with 100 mL hexane containing 5% acetone and the eluate was concentrated to 5 mL. The detection limit for organophosphates on a 40 g sample and a final volume of 10 mL was on the average 0.01 mg/kg. The detection limit for organochlorine pesticides, with the final volume of 25 mL, was 0.005 mg/kg for all pesticides except for p,p'-DDT and endosulfan sulphate, which was 0.01 mg/kg. The detection limit for organochlorine pesticides in sediment, with the final volume of 2 mL, was less than 1 microgram/kg and for organophosphate pesticides less than 10 micrograms/kg when the final volume was made to 0.5 mL. At the detection limits the method produced a very high coefficient of variation for both organochlorine and organophosphate pesticides.

Ritmo cardíaco y embolias sistémicas en la evolución alejada de pacientes con fibrilación auricular paroxística no valvular / Cardiac rhythm and systemic emboli during long term follow up of patients with non-valvular paroxysmal atrial fibrillation

Background: Paroxysmal atrial fibrillation may predispose to systemic embolism. There is little information about the evolution of cardiac rhythm and the occurrence of new embolic events in these patients. Aim: To report the results of a long term follow up of patients with paroxysmal atrial fibrillation. Patients and methods: Patients consulting for non valvular paroxysmal atrial fibrillation were followed for a mean period of 5 years. An EKG, 2D echocardiogram and brain CT scans were performed on admission and at the end of the follow up period to all patients. Results: Sixty eight patients aged 65 ñ 1.5 years were studied. Thirty two had an idiopathic atrial fibrillation, 28 had a history of mild hypertension and 8 had a history of coronary artery disease. Evidence of systemic emboli was found in 17 patients at entry (to the brain in 14 patients). During the follow up 87 per cent of patients required antiarrhythmics, 27 per cent were anticoagulated and 28 per cent received aspirin. Five patients had new embolic episodes. Of these, four had a history of prior embolism. Forty one percent of patients continued in sinus rhythm and remained asymptomatic, 32 per cent had at least one recurrence of paroxysmal atrial fibrillation and nine patients evolved to chronic atrial fibrillation. Five patients required a permanent pacemaker due to symptomatic bradycardia. Conclusions: Most patients with non valvular paroxysmal atrial fibrillation remain in sinus rhythm but one third have recurrences of the arrhythmia. A main risk factor for embolism is the history of previous embolic episodes

Taquicardia ventricular idiopática originada en el ventrículo izquierdo / Idiopathic ventricular tachicardia originated at left ventricle

Patients and methods: We report six patients (five male), aged 35 years old as a mean, with idiopathic left ventricular tachycardia that were subject to conventional electrophysiological studies with atrial and ventricular simulation programs and radiofrequency fulguration, between December 1993 and May 1996. Results: The mean lapse of disease was 24 months and five patients received antiarrytmic medications previously. All tachycardias had a morphology with an image of right bundle branch block. Radiofrequency fulguration was done after obtaining a satisfactory pace mapping of at least 11 of the 12 superficial EKG derivations. The procedure was successful in five patients and two had a relapse. One of the relapsed patients was successfully fulgurated again. Conclusions: Radiofrequency fulguration for idiopathic ventricular tachycardias is a safe and effective therapeutic procedure

Passive diffusion through polymeric membranes: a novel cleanup procedure for analysis of azinphos-methyl and azinphos-ethyl residues in fruits and vegetables.

A novel procedure is described for simple removal of coextractives prior to analysis of fruits and vegetables for azinphos-methyl and azinphos-ethyl residues. The solvent extract is concentrated, placed in a polymeric membrane tube, and then dialyzed in cyclohexane. Both azinphos-methyl and azinphos-ethyl diffuse into the surrounding solvent while coextractants remain inside the membrane. The dialyzing solvent is exchanged during concentration with n-hexane and analyzed without further cleanup by gas-liquid chromatography with a specific thermionic detector. The detection limit for a 25 g grape sample with final volume of extract made to 15 mL was 0.01 mg/kg. Recoveries of both residues from grapes averaged 107% (spike levels of 0.3 to 2.0 mg/kg). From a 20 g spinach sample, recoveries averaged 82% for azinphos-methyl and 72% for azinphos-ethyl when final volume of extract was made to 5 mL (spike levels of 0.1 to 1.0 mg/kg). Recoveries from 20 types of fruits and vegetables (20 g sample spiked at 1 mg/kg for both azinphos-methyl and azinphos-ethyl) were consistently greater than 70%, except for strawberries (61-67%) and avocado (28-34%). The high lipid content of avocado may impede diffusion of azinphos-methyl and azinphos-ethyl through the polymeric membrane. A field evaluation of the procedure showed a strong correlation (r = 0.957) between azinphos-methyl residues on grapes and treatments with 2 spray formulations. The membrane cleanup procedure is a simple and cost-effective alternative to other column or liquid-liquid partitioning procedures for azinphos-methyl and azinphos-ethyl residue analysis.

Valvuloplastía mitral percutánea con técnica de Inoue: resultados de acuerdo al grado de alteración ecográfica / Percutaneous mitral valvuloplasty with Inoue technique: results according to the degree of echographic alterations

Hay cierta incertidumbre referente a las diferencias en resultados de acuerdo al grado de daño preexistente de la válvula mitral en pacientes sometidos a valvulotomía percutánea con el balón de Inoue. Analizamos nuestra serie consecutiva de 126 pacientes (88 por ciento mujeres) tratadas con este procedimiento desde abril de 1990 a diciembre de 1994. Todos los pacientes tuvieron un área valvular mitral (AVM, método de hemipresión por Doppler)< 1,5 cm² e insuficiencia mitral ausente o menor de grado 2/4. El mismo ecocardiografista determinó el AVM antes y 24 a 48 horas después del procedimiento. En 71 por ciento de los pacientes se efectuó una nueva medición del AVM 12 ñ 1 meses después de la valvuloplastía. La valvuloplastía falló en 5 pacientes: no se pudo cruzar la válvula mitral en 3, 1 paciente falleció durante el procedimiento y 2 tuvieron tamponamiento cardiaco tratado por cirugía de emergencia con comisurotomía quirúrgica en el mismo acto. En los 121 pacientes restantes (96 por ciento), la presión media de aurícula izquierda disminuyó de 20 ñ 6 (DS) a 11 ñ 5 mmHg (p <0,001) y el AVM aumentó de 0,96 ñ 0,16 a 1,80 ñ 0,33 cm² (p <0,001). Cuatro de los 5 casos fallidos tenían puntaje de Wilkins ò 10. En 99 pacientes con puntaje £ 7, el AVM aumentó 98 ñ 40 por ciento, en tanto que en 22 pacientes con puntaje de 8 ó 9 el AVM aumentó 79 ñ 41 por ciento (p <0,05). Tres pacientes entre los primeros y 1 entre los segundos desarrollaron insuficiencia mitral ò 3/4. Se observó una disminución leve del AVM en el control efectuado 1 año después de la valvuloplastía (1,83 ñ 0,27 a 1,73 ñ 0,29 cm²). Concluimos que la valvuloplastía mitral percutánea con el balón de Inoue es segura y efectiva en pacientes bien seleccionados (puntaje de Wilkins menor de 10). Los pacientes con puntaje > 7 tienen resultados menos favorables que aquellos con puntajes menores

Prueba de esfuerzo cardiopulmonar en pacientes con insuficiencia cardíaca crónica: comparación con sujetos normales y reproductibilidad de las mediciones / Cardiopulmonary exertion test in patients with chronic cardiac failure: comparison with normal people and reproducibility of measurements

The aim of this work was to measure oxygen consumption and carbon dioxide production during exercise in 21 subjects with cardiac failure and 13 normal subjects. During the resting period, subjects with cardiac failure had higher ventilatory frequency and respiratory quotient than normals. During maximal exercise, the former achieved higher ventilatory frequency and oxygen ventilatory equivalent than normals. In subjects with cardiac failure and normals, anerobic thresholds were 14,4ñ0,9 and 28,8ñ2,2 ml/kg/min respectively and peak oxygen consumptions 17,1ñ1 and 34,4ñ1,7 ml/kg/min respectively. There were less than 10 percent differences in parameters when tests were repeated in 10 subjects with cardiac failure. It is concluded that gas exchange testing may be a reliable and objective assessment method in patients with cardiac failure