[Factors which influence phosphorus removal in hemodialysis]. / Factores en la eliminación de fósforo en hemodialisis.

BACKGROUND: The sustained elevation of phosphorous among patients with end-stage renal failure is associated with elevated mortality rates. Phosphate binding agents are usually necessary to control serum phosphate levels. Phosphate removal during dialysis is limited largely due to the intracellular location of most inorganic phosphorous. The membrane surface, the frequency and the duration of therapy have proved to be very important factors in the serum phosphate control. THE AIM of our work is to investigate the influence on phosphate removal of factors that normally participate in the haemodialysis session: Plasma phosphate level (Php), treatment duration, membrane surface, high or low-flux membranes, the vascular access, dialysate flux , the volume of blood passing through the dialyzer (L) in each dialysis session and the blood flow during the first hour of dialysis. On 16 patients, we also had the possibility of comparing phosphate removal with 1.8 m(2) high-flux haemodialysis, 1.8 m(2) on-line hemodiafiltration and the on-line technique with the new Helixone dialyzer Fresenius Fx100. METHODS: 108 haemodialysis patients, 62% men, 38% women aged 21-82 years (61+/-14;mean+/-sem),) were selected for the study. Mean treatment time 4.14+/-0.41 hours (range 3.5-5 hours). The vascular access was an arterio-venous fistula in eighty five (78%) and a double lumen tunnelled catheter 23 (22%). Patients were studied under their normal every day conditions. High-flux membrane was used by 31 (30%) patients and low-flux membrane by 77 (70%). Membrane surface was: 1.7 m2:17 (16%); 1.8 m2:77 (71%); 2,1 m2:14 (13%). Dialysate flux was: 500 ml/min. 55 patients; 700 ml/min: 53 patients. In 16 out of 108 patients we had the possibility of using on-line hemodiafiltration with ultrapure bicarbonate-buffered dialysate. Phosphate mass removal (MPO4) was calculated using the formula:MPO4=0.1 t-17+50 Cds 60+11Cb 60 (1), where t is treatment time in minutes, Cds60 and Cb60 are phosphate concentrations in dialysate and plasma measured at 60 min from the beginning of hemodialysis in mg/dl, and MPO4 is the estimated phosphate removed in mg/treatment. RESULTS: We found a good correlation between phosphate removal and serum phosphate levels (p=0.01), but not with the membrane surface or treatment duration. Phosphate removal was 640+/-180 mg/session with low-flux membrane and 700+/-170 mg/session with high-flux membrane (p=0.280). The MPO4 was 720+/-190 mg/treatment in patients with a AV fistula and 620+/-180 in patients with a tunnelled catheter (p=0.023). We found a good correlation between phosphate removal and the volume of blood (L) that passed the dialyzer in each session (r=0.001) but we did not find a correlation between phosphate removal and KT/Vurea, the dialysate flux or the ultra filtration. On-line technique did not increased the MPO4(733+/-280 mg, p=0.383). The on-line technique with the new dialyzer (Fresenius Fx100), increased the phosphate removal to 759+/-199 mg/session (p=0.057). CONCLUSION: Phosphate removal during dialysis is influenced by Plasma phosphate levels, the volume of blood that passed the dialyzer and the vascular access. Uniformity on time and membrane surface could explain the abs cense of influence in our case. The ultra filtration, dialysate flux, membrane permeability or on-line hemodiafiltration does not influence the phosphate removal. The new membrane helixone with 2,1 m2 (Fresenius Fx100) increases phosphate removal probably because the membrane surface is higher.

Factores en la eliminación de fósforo en hemodiálisis / Factors which influence phosphorus removal in hemodialysis

La elevación de los niveles plasmáticos de fósforo se asocia a tasas elevadas de mortalidad en los pacientes en diálisis. La eliminación de fósforo con la hemodiálisis es limitada, debido a la localización intracelular del mismo. La superficie de la membrana del dializador, el tiempo y la frecuencia de la diálisis influyen claramente en su eliminación. El objetivo de este trabajo es analizar la influencia en la eliminación de fósforo de los factores relacionados con la sesión de hemodiálisis: El fósforo plasmático (Pp), la duración de la sesión, la superficie del dializador, la permeabilidad de la membrana, la naturaleza del acceso vascular, el flujo de sangre en la primera hora, el volumen de sangre depurado (L), la ultra filtración, el KT/V de urea y la técnica de hemodiafiltración on-line. Métodos: Se seleccionaron 108 pacientes en hemodiálisis. El 78% disponía de FAVI y 22% de catéter tunelizado. La membrana del dializador fue de polisulfona de alta permeabilidad en 31 (30%) y de permeabilidad media en 77 (70%). La superficie del dializador fue: 1,7 m2: 17 (16%); 1,8 m2: 77 (71%); 2,1 m2: 14 (13%). Flujo del líquido de diálisis: 500 ml/min: 55 pacientes; 700 ml/min: 53 pacientes. Duración de la sesión: 4,14 ± 0,41 (Rango 3,5-5 horas). El 85% se dializaban entre 4 y 5 horas. Se realizó un corte transversal en el que se determinó la eliminación de fósforo en una sesión de mitad de semana simultáneamente a la realización del KT/V de urea (Bicompartimental). En la misma sesión se determinó la eliminación de fósforo (MPO4), utilizando la fórmula: MPO4 = 0,1 t-17 + 50 Cds 60 + 11 Cb 60 (1). Se analizó su relación con los parámetros señalados anteriormente. En un segundo tiempo, a 63 pacientes se les modificó únicamente la permeabilidad del dializador cambiando los de alta a media permeabilidad y viceversa de modo que cada uno era su propio control. La MPO4 se calculó y comparó en ambas situaciones. En 16 pacientes en los que tuvimos tecnología para realizar hemodiafiltración on-line, se comparó la eliminación de fósforo con hemodiálisis de alto flujo, hemodialiltración on-line con la misma membrana y hemodiafiltración on-line con la membrana Helixona de 2,1 m2 de superficie. Resultados: La eliminación de fósforo (MPO4) guarda una buena correlación con los niveles plasmáticos del mismo (p = 0,01) , con los litros de sangre depurados (p = 0,01) y con la existencia de una fistula (p = 0,05), pero no observamos relación con la duración de la sesión, con el flujo del líquido de diálisis, con el KT/V de urea ni con la ultra filtración o la superficie de la membrana del dializador en nuestro caso. Fue de 700 ± 170 mg / sesión con membrana de alta permeabilidad y de 640 ± 180 mg / sesión con membrana de media permeabilidad (p = 0,280). Al modificar la permeabilidad de la membrana siendo el paciente su propio control, tampoco hubo diferencias en la eliminación. La MPO4 es de 720 ± 190 mg/ tratamiento en los pacientes que disponen de una FAVI y de 620 ± 180 mg /tratamiento en los pacientes que disponen de un catéter (p = 0,023). Las diferencias en los pacientes con FAVI o catéter se deben fundamentalmente al flujo de sangre tanto en la 1ª hora de diálisis como al total de litros depurados (p = 0,001). Sin embargo al realizar un analisis multivariante, son los niveles de fósforo plasmático y los litros de sangre depurada los que predicen la eliminación de fósforo. En los pacientes en que se pudo realizar hemofiltración on-line, la eliminación de fósforo fue de 725 ± 202 mg/sesión de HD de alto flujo, 733 ± 280 mg/ sesión de hemodiafiltración con reposición de 18L postdilución (p = 0,383) y de 759 ± 199 mg/sesión con hemodiafiltración con membrana de helixona de 2,1 m2 (p = 0,057). En conclusión en nuestra experiencia, en la depuración de fósforo en un sesión de diálisis intervienen además del fósforo plasmático, la cantidad de sangre depurada que es en general superior cuando el acceso vascular es una FAVI. Otros factores como la duración de la sesión y la superficie del dializador eran muy homogéneos y no han podido por tanto mostrar diferencias. La ultrafiltración, el flujo del líquido de diálisis, la permeabiliad de la membrana o la técnica de hemodiafiltración on-line no la incrementa de forma significativa

Background: The sustained elevation of phosphorous among patients with endstage renal failure is associated with elevated mortality rates. Phosphate binding agents are usually necessary to control serum phosphate levels. Phosphate removal during dialysis is limited largely due to the intracellular location of most inorganic phosphorous. The membrane surface, the frequency and the duration of therapy have proved to be very important factors in the serum phosphate control. The aim of our work is to investigate the influence on phosphate removal of factors that normally participate in the haemodialysis session: Plasma phosphate level (Php), treatment duration, membrane surface, high or low-flux membranes, the vascular access, dialysate flux, the volume of blood passing through the dialyzer (L) in each dialysis session and the blood flow during the first hour of dialysis. On 16 patients, we also had the possibility of comparing phosphate removal with 1.8 m2 high-flux haemodialysis, 1.8 m2 on-line hemodiafiltration and the online technique with the new Helixone dialyzer Fresenius Fx100®. Methods: 108 haemodialysis patients, 62% men, 38% women aged 21-82 years (61 ± 14; mean ± sem), were selected for the study. Mean treatment time 4.14 ± 0.41 hours (range 3.5-5 hours).The vascular access was an arterio-venous fistula in eighty five (78%) and a double lumen tunnelled catheter 23 (22%). Patients were studied under their normal every day conditions. High-flux membrane was used by 31 (30%) patients and low-flux membrane by 77 (70%). Membrane surface was: 1.7 m2: 17 (16%); 1.8 m2: 77 (71%); 2,1 m2: 14 (13%). Dialysate flux was: 500 ml/min 55 patients; 700 ml/min 53 patients. In 16 out of 108 patients we had the possibility of using on-line hemodiafiltration with ultrapure bicarbonate-buffered dialysate. Phosphate mass removal (MPO4) was calculated using the formula: MPO4 = 0.1 t-17 + 50 Cds 60 + 11 Cb 60 (1), where t is treatment time in minutes, Cds 60 and Cb 60 are phosphate concentrations in dialysate and plasma measured at 60 min from the beginning of hemodialysis in mg/dl, and MPO4 is the estimated phosphate removed in mg/treatment Results: We found a good correlation between phosphate removal and serum phosphate levels (p = 0.01) , the volume of blood (L) that passed the dialyzer in each session (r = 0.01) and the AV fistula as vascular access (p = 0.05), but not with the membrane surface, KT/V, the dialysate flux, the ultra filtration or treatment duration. Phosphate removal was 640 ± 180 mg/session with low-flux membrane and 700 ± 170 mg/session with high-flux membrane (p = 0.280). The MPO4 was 720 ± 190 mg/treatment in patients with a AV fistula and 620 ± 180 in patients with a tunnelled catheter (p = 0.023). On-line technique did not increased the MPO4 (733 ± 280 mg, p = 0.383). The on-line technique with the new dialyzer (Fresenius Fx100), increased the phosphate removal to 759 ± 199 mg/session (p = 0.057)

Hyperhomocyst(e)inemia is a risk factor of secondary vascular events in stroke patients.

OBJECTIVE: Moderate hyperhomocyst(e)inemia is an independent risk factor for stroke, but it is unclear whether it also would be a risk factor for secondary vascular events after stroke. METHODS: Longitudinal study of 137 consecutive ischemic stroke patients (age 45-91 years) who were prospectively studied with a standard clinical protocol. Vascular events (stroke recurrence, ischemic heart disease, deep venous thrombosis or peripheral arterial disease) were identified during 2 years of follow-up. Serum homocyst(e)ine was determined 3 months after the stroke. The cumulative proportion of patients with homocyst(e)ine above or below the 75th percentile who survived free of vascular events was determined by Kaplan-Meier analysis. Cox models were used to estimate the relative risk of vascular events after controlling for other confounding factors. RESULTS: Serum homocyst(e)ine was significantly higher in patients with vascular events (26.2 versus 19.4 micromol/l; p = 0.016). The cumulative proportion of patients with vascular events was 46.5% in the group with homocyst(e)ine over the 75th percentile (>30 micromol/l) and 20.2% in the other group (log-rank test 7.5; p = 0.0062). After adjustment for age, sex, high blood pressure, diabetes, heart disease, previous cerebrovascular disease, smoking and serum cholesterol, the relative risk of vascular event for patients above compared with those below the 75th percentile of serum homocyst(e)ine was 2.8 (CI 95% 1.3-6; p = 0.01). CONCLUSION: Hyperhomocyst(e)inemia is a significant risk factor for vascular events after ischemic stroke. This finding is independent of other risk factors such as hypertension, and may have therapeutic relevance in the secondary prevention of vascular diseases in stroke patients.

[Nutrient and food consumption by ages and gender in school children from the Community of Madrid (CAENPE)]. / Consumo de alimentos y nutrientes por edades y sexo en escolares de la Comunidad de Madrid (CAENPE).

UNLABELLED: The objective of the present work was to know the consume of foodstuffs and nutrients among schoolchildren in the Madrid Autonomous Community and also the relative contribution of each group of foodstuffs to the overall intake of macronutrients. This study had a sectional observational design involving 2,608 children (51% males and 49% females) with ages ranging from 6 to 14 years who were randomly recruited from conglomerate of schools, according to socio-economic status and rural/urban residence. The inquiry on nutrients in 4 non consecutive days was analyzed (2 "24 hour-recall" and 2 "intake recall"). RESULTS: a) the consume of proteins, lipids, and carbohydrates represented 17%, 43% and 40% of the total caloric value, respectively; b) the intake of meats, sausages, sweets, tidbits, and processed products was very high. This fact is in origin of the excessive total and saturated lipid intake; c) there was a scarce intake of vegetables, cereals and potatoes among children of all ages and dairy products in children older than 12 years; d) the intake of legumes, eggs and fruits was appropriate; e) males consumed proportionally higher amounts than females of the following groups of foodstuffs: cereals, sweets and tidbits. The consume of meat, sausages, fish, eggs, potatoes, dry fruits and dairy products was similar in both sexes. Females consumed proportionally more fat foodstuffs, vegetables, fruits, legumes and processed products; f) females consumed a diet with a still higher lipid and protein content than males. These findings can serve as a basis to develop educational guidelines with a practical impact on family and school menus.

[Food consumption and the nutritional status of schoolchildren of the Community of Madrid (CAENPE): general methodology and overall food consumption. Consumo de alimentos y estado nutricional de la población escolar]. / Consumo de alimentos y estado nutricional de los escolares de la Comunidad de Madrid (CAENPE): metodología general y consumo global de alimentos.

The CAENPE study (Food Consumption and Nutritional State of the School Population) was a transversal observational study funded and promoted by the Directorate-General of Food Hygiene in the Ministry of Health, implemented in 1991-93, with the main aim of quantifying food consumption in the school population (6-14 years of age) in the Regional Community of Madrid, together with an anthropometric study and nutritional analysis of that population. This project sets our the General Methodology for the study, paying particular attention to the sampling design, to ensure that the sample is representative of the community, and the results of the overall consumption of food and its comparison with recommended diet and other population studies. Quantification shows a high and rising consumption of meat, meat products, sweets, snacks and prepared dishes, suitable consumption of eggs, legumes and fruit and a notable lack of greens, vegetables and potatoes. The basic results underline the need to introduce educational measures with practical effect on home and school menus.

Decreased serum selenium concentrations in patients with Parkinson's disease.

Selenium is an essential component of the antioxidant enzyme glutathione peroxidase. The activity of this enzyme is reduced in the substantia nigra of patients with Parkinson's disease (PD), but the results of studies on erythrocytes are controversial. We compared the serum levels of selenium and the 24 h urinary selenium excretion (measured by hydride generation atomic absorption spectrophotometry) in 29 PD patients and 30 matched controls. Serum selenium levels were significantly lower in PD patients than in controls (34.6 ± 2.35 and 45.2 ± 3.83 µg/l, p < 0.05) while urinary excretion was similar for both groups (47.1 ± 6.25 and 45.5 ± 5.38 µg/24 h). These values were not influenced by antiparkinsonian drugs, and they did not correlate with age, age at onset and duration of the PD, scores of the Unified PD Rating Scale or the Hoehn and Yahr staging in the PD group. These results might suggest a possible role of low serum selenium levels in the risk for, or a consequence of the oxidative stress in PD.

Nuevos mecanismos de resistencia antibiotica en Enterococcus SPP: significacion epidemiologica en el Uruguay / New mechanisms of antibiotics resistance in Enterococcus spp: epidemiological significance in Uruguay

Enterococcus sp se aislan con frecuencia creciente de infecciones graves hospitalarias. Resistencia de alto nivel a aminoglucosidos, glycopeptidos y beta lactamicos se asocian con perdida del efecto sinergico de las combinaciones usadas para el tratamiento de las infecciones graves por estos agentes. Desde 1992 se ha realizado la vigilancia de estos mecanismos de resistencia, que no son detectados por las pruebas habituales de laboratorio, a los efectos de determinar su incidencia en nuestro medio. Se estudiaron 57 aislamientos significativos de Enterococcus spp provenientes de diferentes centros de salud. Se utilizo una prueba de tamizado en agar para detectar la resistencia de alto nivel a aminoglucosidos; la produccion de beta lactamasa por hidrolisis de nitrocefina y la CIM de vancomicina y teicoplanina por metodo de dilucion en agar. Se identificaron 3 cepas con resistencia de alto nivel a aminoglucosidos y no se detecto resistencia a glicopepticos ni produccion de beta lactamasa. Este hecho sumado al uso extensivo hospitalario de antibioticos que pueden seleccionar estos agentes, hace necesario vigilar en forma sistematica en el laboratorio clinico la resistencia de alto nivel a aminoglucosidos y a glicopepticos