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)

[Application of Mossbauer spectroscopy to the study of hemoglobinopathies. Preliminary experience]. / Aplicación de la espectroscopia Moessbauer al estudio de hemoglobinopatías. Experiencias preliminares.

37Fe Moessbauer spectroscopy has been applied to the study of iron deposits in patients with altered iron metabolism. Haematological parameters were also studied in order to analyse their relationship with Moessbauer results. Within the aim of this research, 12 samples of packed red blood cells were analysed: 6 with beta-thalassaemia major, 2 with S-beta-thalassaemia, 1 with sickle cell anaemia and 3 from normal subjects used as control for Moessbauer spectroscopy. Moessbauer spectra of 6 red blood cells samples showed that besides the two components, i.e., oxy and deoxy haemoglobin present in samples of normal subjects, appears a third component with Moessbauer parameters corresponding to ferritin-like iron. Correlation of % transferrin saturation (TS %) with ferritin-like iron (r = 0.90, p less than 0.05) as well as between TS % and the ratio ferritin-like iron/Hb iron (r = 0.91, p less than 0.05) was found. A tendency to correlation of serum ferritin (SF) with ferritin-like iron (r = 0.90, p less than 0.05) as well as between TS % and the ratio ferritin-like iron/Hb iron (r = 0.91, p less than 0.05) was found. A tendency to correlation of SF with ferritin-like iron (r = 0.78) and with the ratio ferritin-like iron/Hb iron, was also observed. It can be concluded that Moessbauer spectroscopy could be a useful technique in the study of this kind of pathology.

Impairment of natural killer (NK) function in carriers and patients with thalassemia major.

To evaluate natural killer cytotoxicity (NKC) and its regulation by interferon (IFN) in thalassemia major (TM), we studied 19 patients, 10 carriers (parents of 10 different patients) and 35 normal subjects (children and adults) as controls. We have found a diminished NKC, as well as a decrease in the percentages of cells bearing IgGFc receptors in TM patients, whereas they were normal in TM carriers. Although alpha-IFN enhanced NKC in TM patients and carriers, Con A (an IFN inducer) had no enhancing effect on NKC from either patients or carriers. These agents did not modify the expression of IgGFc receptors in cells from TM patients, carriers or normal controls. Our results indicate that TM patients have a defect in NK cell maturation or activation, which is reversed by alpha-IFN. The failure of TM patients and carriers to respond to Con A suggests a defect in NKC regulation which might be related to a genetic origin.

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)