Seasonal variability in 7Be depositional fluxes at Granada, Spain.

Measurement of 7Be depositional fluxes at Granada, Spain (37 degrees 10'50''N-3 degrees 35'44''W, altitude 670 m) in the period 1995 through 1998 indicates substantial variations between the four seasons and also between corresponding seasons in different years, ranging from 23.6 to 242 Bq m(-2) per season. A strongly positive correlation with precipitation is shown, which explains about 70% of the variations in the 7Be depositional fluxes over the 16 seasons studied. The depositional 7Be flux is on the average highest in the fall and lowest in the summer. The study shows that precipitation primarily controls the 7Be depositional flux and plays a dominant role in the removal of 7Be from the troposphere. The average annual 7Be depositional flux at Granada amounts to 469+145 Bq m(-2).

Seasonal 7Be concentrations in near-surface air of Granada (Spain) in the period 1993-2001.

Near-surface air samples for assessment of seasonal 7Be levels were taken weekly at Granada, Spain, (37 degrees 10'50"N-3 degrees 35'44"W, altitude 670 m) in the period 1993-2001. The 7Be levels measured reflect strong seasonal trends. Concentrations during autumn and/or winter showed a minimum (ca. 1.5 mBq/m3), and in each year a fallout maximum was found in summer (ca. 7.6 mBq/m3). Multiple regression of 7Be concentrations with temperature and rainfall, and with sunspot number explained about 71% of the variance in the 7Be data. The data reveal strong variations in the mean annual 7Be concentrations due to variations in the flux of cosmic galactic primary radiation caused by the 11-year sunspot cycle. A difference of a factor of 2.6 was found between the highest level (5.8 mBq/m3) obtained in 1996 (beginning of the solar cycle 23) and the lowest (2.6 mBq/m3) obtained in 2000 (maximum of the solar cycle 23).

Bleeding time in normal children.

PURPOSE: Because there is little information on bleeding times (BTs) in children we initiated the following study. MATERIALS AND METHODS: Normal children undergoing elective surgery and adult volunteers had their bleeding times measured with a disposable device (Simplate) with a vertical incision in the forearm. Results in children (four age groups) and adults, male and female, were compared. RESULTS: The mean time in children was 270 s with a 95th percentile of 420 s compared with a mean time in adults of 320 s and a 95th percentile of 480 s (p = 0.001). Although the values in the various age groups and sexes were different, only sex had a statistically different value in adults. CONCLUSIONS: The following reference values should be used for children: 0-4 years, 4 +/- 1 min; boys > 4 years, 5 +/- 1 min; girls > 4 years, 5.5 +/- 1 min. We conclude that results obtained in children are significantly shorter than those obtained in normal adult subjects.

[S hemoglobinopathies in Argentina]. / Hemoglobinopatías S en la Argentina.

Hb S is among the most prevalent abnormal hemoglobins, its distribution being related to areas where malaria is or was once endemic. In order to establish the characteristics of sickle cell hemoglobinopathies in Argentina, all cases diagnosed in a 30-year period in the Hematology Unit of R. Gutiérrez Children's Hospital were revised. Hb S diagnoses were based minimally on a positive sickling test; in most cases, RBC and reticulocyte counts, Hb concentration, and PCV were also performed, and red cell indices were obtained according to standardized procedures. Concentrations of Hb A2 and Hb S were calculated by elution of cellulose acetate strips following electrophoresis, and Hb F was measured by alkali denaturation. Of the 925 hemoglobinopathies diagnosed, Hb S was found in 116 (12.5%): sickle-cell trait (AS) in 75, sickle-cell disease (SCD) in 8, S/beta-thalassemia (s/beta-thal) in 23, SCD or S/beta-thal in 8, S/D in 1; beta-thalassemia syndromes accounted for 785 cases (84.9%). Major findings in AS were: (a) all cases came from northern and central areas of the country, neighboring countries, and other countries (Italy and Arabic nations); (b) black ancestry was found in 15 out of 75 (20%); (c) mean hematological values were normal (Table 3), and mean Hb S level was 37.1%; (d) of 57 AS patients whose blood smears were examined, 18 showed red cell abnormalities (microcytosis and/or hypochromia); (e) AS cases with altered erythrocyte morphology had significantly lower Hb, PCV, MCH, and MCV levels when compared with those with normal morphology (Tables 5, 6).(ABSTRACT TRUNCATED AT 250 WORDS)

Hemoglobinopatías S en la Argentina. / [S hemoglobinopathies in Argentina]

Hb S is among the most prevalent abnormal hemoglobins, its distribution being related to areas where malaria is or was once endemic. In order to establish the characteristics of sickle cell hemoglobinopathies in Argentina, all cases diagnosed in a 30-year period in the Hematology Unit of R. Gutiérrez Childrens Hospital were revised. Hb S diagnoses were based minimally on a positive sickling test; in most cases, RBC and reticulocyte counts, Hb concentration, and PCV were also performed, and red cell indices were obtained according to standardized procedures. Concentrations of Hb A2 and Hb S were calculated by elution of cellulose acetate strips following electrophoresis, and Hb F was measured by alkali denaturation. Of the 925 hemoglobinopathies diagnosed, Hb S was found in 116 (12.5

): sickle-cell trait (AS) in 75, sickle-cell disease (SCD) in 8, S/beta-thalassemia (s/beta-thal) in 23, SCD or S/beta-thal in 8, S/D in 1; beta-thalassemia syndromes accounted for 785 cases (84.9

). Major findings in AS were: (a) all cases came from northern and central areas of the country, neighboring countries, and other countries (Italy and Arabic nations); (b) black ancestry was found in 15 out of 75 (20

); (c) mean hematological values were normal (Table 3), and mean Hb S level was 37.1

; (d) of 57 AS patients whose blood smears were examined, 18 showed red cell abnormalities (microcytosis and/or hypochromia); (e) AS cases with altered erythrocyte morphology had significantly lower Hb, PCV, MCH, and MCV levels when compared with those with normal morphology (Tables 5, 6).(ABSTRACT TRUNCATED AT 250 WORDS)

Hemoglobinopatías S en la Argentina. / [S hemoglobinopathies in Argentina]

Hb S is among the most prevalent abnormal hemoglobins, its distribution being related to areas where malaria is or was once endemic. In order to establish the characteristics of sickle cell hemoglobinopathies in Argentina, all cases diagnosed in a 30-year period in the Hematology Unit of R. Gutiérrez Childrens Hospital were revised. Hb S diagnoses were based minimally on a positive sickling test; in most cases, RBC and reticulocyte counts, Hb concentration, and PCV were also performed, and red cell indices were obtained according to standardized procedures. Concentrations of Hb A2 and Hb S were calculated by elution of cellulose acetate strips following electrophoresis, and Hb F was measured by alkali denaturation. Of the 925 hemoglobinopathies diagnosed, Hb S was found in 116 (12.5

): sickle-cell trait (AS) in 75, sickle-cell disease (SCD) in 8, S/beta-thalassemia (s/beta-thal) in 23, SCD or S/beta-thal in 8, S/D in 1; beta-thalassemia syndromes accounted for 785 cases (84.9

). Major findings in AS were: (a) all cases came from northern and central areas of the country, neighboring countries, and other countries (Italy and Arabic nations); (b) black ancestry was found in 15 out of 75 (20

); (c) mean hematological values were normal (Table 3), and mean Hb S level was 37.1

; (d) of 57 AS patients whose blood smears were examined, 18 showed red cell abnormalities (microcytosis and/or hypochromia); (e) AS cases with altered erythrocyte morphology had significantly lower Hb, PCV, MCH, and MCV levels when compared with those with normal morphology (Tables 5, 6).(ABSTRACT TRUNCATED AT 250 WORDS)

Niveles de ácido ascórbico sérico y plaquetario en pacientes con hemoglobinopatías / Serum and platelet ascorbic acid levels in patients with hemoglobinopathies

Es conocida la asociación entre depósitos de hierro aumentados y bajo nivel de ácido ascórbico (sérico y tisular). En base a ello, se consideró de interés medir dicha vitamina en los pacientes afectados de hemoglobinopatías severas. Ingresaron al estudio 25 casos (20 beta-talasemias homocigotas, 4 Hb-S/ beta-talasemias y 1 Hb-S homocigota; rango de edad: 1-23 años). Para el dosaje del ácido ascórbico sérico y plaquetario se usó una modificación del método de Denson y Bowers; el estado de los depósitos de hierro se determinó a través de la ferritina sérica. Los resultados mostraron que: a) de 5 pacientes con valores de ferritina sérica normales o sólo elevados moderadamente, los niveles de vitamina C eran normales en 3 y descendidos en 2,y b) de los 20 casos restantes, todos con valores de ferritina sérica elevados, los niveles de vitamina C sérica o plaquetaria estaban en límites normales inferiores en 4 y en los otros 16 francamente descendidos. Un enfermo presentó signos clínicos atribuibles al déficit vitamínico. Se destaca la importancia de conocer los niveles de ácido ascórbico, especialmente en los pacientes que recibirán terapia con deferoxamina (la suplementación con vitamina C incrementa la sideruria); la suplementación vitamínica estaría en cambio contraindicada en aquellos que no reciben el quelante, pues se ha sugerido que la deficiencia de ácido ascórbico actuaría protegiendo el parénquima tisular a expensas de un mayor depósito del hierro en el sistema monocitos-macrófagos

Talasemia mayor: terapia quelante con deferoxamina / Thalassemia major: chalation therapy with deferoxamine

Para evaluar los resultados de un año de tratamiento con deferoxamina subcutánea continua lenta, cuya meta es alcanzar un balance negativo del hierro (Bal-Fe) (que se elimine más del que se incorpora con las transfusiones), se estudiaron 10 talasémicos mayores (6 varones y 4 mujeres, edad 2-17 años) sometidos a dicha terapia y bajo régimen de "hipertransfusión moderada" (además de suplementación con ácido fólico y vitamina C). Los depósitos de Fe se midieron dosando la ferritina sérica, la incorporación por el volumen de glóbulos desplasmatizados transfundidos en el lapso estudiado y la eliminación multiplicando la sideruria diaria promedio por el total de días que recibió el quelante (más un 25% correspondiente a la eliminación fecal, no determinada). Los resultados muestran que sólo 2 pacientes (2 niñas de 12 años) lograron Bal-Fe; en otros 5 la respuesta fue buena pero insuficiente y en los 3 restantes (todos de corta edad) la respuesta fue más limitada (depósitos aun escasos?). Se concluye que los resultados obtenidos son satisfactorios, pues con mayores dosis de deferoxamina y/o esplenectomía (que reduce el requirimiento transfusional) sería factible una negativización del balance en los que todavía no lo lograron; y en los de menor edad, no se descarta que la terapia retrase o prevenga una sobrecarga exagerada, hasta tanto el crecimiento permita la aplicación de las otras medidas (dosis superiores, esplenectoía). Pese a sus desventajas (alto costo, aceptación dificultosa), consideramos que momentáneamente constituye el tratamiento de elcción

Niveles de ácido ascórbico sérico y plaquetario en pacientes con hemoglobinopatías / Serum and platelet ascorbic acid levels in patients with hemoglobinopathies

Es conocida la asociación entre depósitos de hierro aumentados y bajo nivel de ácido ascórbico (sérico y tisular). En base a ello, se consideró de interés medir dicha vitamina en los pacientes afectados de hemoglobinopatías severas. Ingresaron al estudio 25 casos (20 beta-talasemias homocigotas, 4 Hb-S/ beta-talasemias y 1 Hb-S homocigota; rango de edad: 1-23 años). Para el dosaje del ácido ascórbico sérico y plaquetario se usó una modificación del método de Denson y Bowers; el estado de los depósitos de hierro se determinó a través de la ferritina sérica. Los resultados mostraron que: a) de 5 pacientes con valores de ferritina sérica normales o sólo elevados moderadamente, los niveles de vitamina C eran normales en 3 y descendidos en 2,y b) de los 20 casos restantes, todos con valores de ferritina sérica elevados, los niveles de vitamina C sérica o plaquetaria estaban en límites normales inferiores en 4 y en los otros 16 francamente descendidos. Un enfermo presentó signos clínicos atribuibles al déficit vitamínico. Se destaca la importancia de conocer los niveles de ácido ascórbico, especialmente en los pacientes que recibirán terapia con deferoxamina (la suplementación con vitamina C incrementa la sideruria); la suplementación vitamínica estaría en cambio contraindicada en aquellos que no reciben el quelante, pues se ha sugerido que la deficiencia de ácido ascórbico actuaría protegiendo el parénquima tisular a expensas de un mayor depósito del hierro en el sistema monocitos-macrófagos (AU)

Talasemia mayor: terapia quelante con deferoxamina / Thalassemia major: chalation therapy with deferoxamine

Para evaluar los resultados de un año de tratamiento con deferoxamina subcutánea continua lenta, cuya meta es alcanzar un balance negativo del hierro (Bal-Fe) (que se elimine más del que se incorpora con las transfusiones), se estudiaron 10 talasémicos mayores (6 varones y 4 mujeres, edad 2-17 años) sometidos a dicha terapia y bajo régimen de "hipertransfusión moderada" (además de suplementación con ácido fólico y vitamina C). Los depósitos de Fe se midieron dosando la ferritina sérica, la incorporación por el volumen de glóbulos desplasmatizados transfundidos en el lapso estudiado y la eliminación multiplicando la sideruria diaria promedio por el total de días que recibió el quelante (más un 25% correspondiente a la eliminación fecal, no determinada). Los resultados muestran que sólo 2 pacientes (2 niñas de 12 años) lograron Bal-Fe; en otros 5 la respuesta fue buena pero insuficiente y en los 3 restantes (todos de corta edad) la respuesta fue más limitada (depósitos aun escasos?). Se concluye que los resultados obtenidos son satisfactorios, pues con mayores dosis de deferoxamina y/o esplenectomía (que reduce el requirimiento transfusional) sería factible una negativización del balance en los que todavía no lo lograron; y en los de menor edad, no se descarta que la terapia retrase o prevenga una sobrecarga exagerada, hasta tanto el crecimiento permita la aplicación de las otras medidas (dosis superiores, esplenectoía). Pese a sus desventajas (alto costo, aceptación dificultosa), consideramos que momentáneamente constituye el tratamiento de elcción (AU)