[Hereditary persistence of fetal Hb and its association with Hb S. 1st case found in Costa Rica]. / Persistencia hereditaria de Hb fetal y su asociación con Hb S. Primer caso hallado en Costa Rica.

An electrophoretic pattern of Hb S + Hb F, the relative concentration of this last being 37%, was found in a phenotypically mestizo 3 year-old child of Costa Rica. The genotype of the child was G gamma/A gamma, with a ratio of 1:1. Both hereditary alterations were disperse, according to the family study performed, which showed Hb S plus hereditary persistence of foetal haemoglobin of the African type G gamma A gamma (delta beta o). This case is briefly discussed, along with the molecular heterogeneity of HPFH and the importance of the differential diagnosis of electrophoretic patterns found in Hb S + Hb F patients.

A glucose-6-phosphate dehydrogenase variant, Gd(-) Santamaria found in Costa Rica.

Red cell glucose-6-phosphate dehydrogenase (G6PD) deficiency is an X-chromosomal-linked abnormality often associated with hemolytic anemia. The G6PD variants obtained from 2 unrelated males, one associated with enzyme deficiency and history of hemolytic jaundice, and the other associated with enzyme deficiency but no hemolytic problems, were examined. Although the 2 subjects have no known consanguinity, the two enzymes could not be distinguished from each other in respect to their electrophoretic mobilities and kinetic properties, both exhibiting slower than normal anodal electrophoretic mobility, lower Km for G6P and NADP and higher rate of utilization of 2-deoxy-G6P and deamino-NADP. An unique double-banded pattern was observed in starch gel electrophoresis at pH 7.0 and pH 8.6. The variant is distinguished from all reported Gd variants, and it is designated Gd(-) Santamaria.

Hemoglobinometria.Normalizacion de la metodologia. Preparacion nacional del estandar de calibracion y de hemolizado control. / Hemoglobinometry.Standardization of the methodology.National preparation of the standard of calibration and hemolized control

Se indican las caracteristicas esenciales del metodo de la HiCN para la medicion cuantitativa de Hb. Se hace ver la importancia del diluente de Van Kampen y Zijestra (VKZ), para tales efectos y la aplicabilidad de las soluciones patron para la calibracion de los fotometros. En detalle se especifica la preparacion nacional del patron concentrado de HiCN (CIANO-CIHATA)y del hemolizado control (HEMOCIHATA).Finalmente se propone un practico programa de control de calidad y se indica un colorario sobre los errores sistematicos en los que se puede incurrir en la hemoglobinometria

Escrutinio de hemoglobinopatias y G6PD en una poblacion italiana radicada en Costa Rica. / Detection of hemoglobinopathies and G6PD in a italian population radicated in Costa Rica

En una poblacion de origen italiano que radica en el canton de Coto Brus, Puntarenas, se pudo detectar la presencia de dos casos de beta-tal menor en 64 individuos estudiados. Para el escrutinio y caracterizacion definitiva del fenotipo talasemico se siguio con protocolos ampliamente estudiados en el CIHATA. No se encontro ningun caso deficiente en G6PD ni la presencia de Hbs anormales

Beta talasemia mayor (enfermedad de Colley). Consideraciones sobre biologia molecular y estudio de una nueva familia. / Beta talasemia major (Colley disease). Considerations about molecular biology and study of a new family

En un nino de un ano de edad, procedente de Nicaragua, severamente anemico, se puso en evidencia un caso de beta-tal homocigota de la variedad beta+ -tal, a juzgar por los resultados del hemoglobinograma. Se destaca en sus padres la herencia de beta-tal menor de la variedad HbA2 alta. Se hace una breve resena sobre la biologia molecular en hemoglobinopatias y sobre algunas caracteristicas clinicas y geneticas de las beta-tal

The clinical significance of atrial pacing-induced Mobitz I atrioventricular block in patients with coronary artery disease.

Two hundred consecutive patients with a history of chest pain undergoing cardiac catheterization, coronary angiography and atrial pacing have been analyzed to assess the clinical significance of Mobitz I atrioventricular (A-V) block developing with the stress of atrial pacing. Of 160 patients with coronary artery disease, 26 (16%) developed Mobitz I A-V block at rates below 140 beats/min. Eighteen of these 26 patients (69%) had electrocardiographic evidence of old inferior wall myocardial infarction, compared to only 34 of the remaining 134 patients (29%) (P = less than 0.01). During the mean follow-up of 29.5 months (range 18-50 months) none of the 26 patients has developed spontaneous second or third degree A-V block. Twenty-three of the 26 patients had an exercise test within one week of the pacing study. No A-V block was noticed during or immediately following exercise, although the mean heart rate attained during exercise was higher than the mean pacing rate at which the A-V block occurred (136 +/- 5 vs 122 +/- 3, P = less than 0.01). Eighteen of these 23 achieved heart rates equal to or higher than the pacing rate at which A-V block developed. Nineteen (83%) shortened their P-R interval during exercise and 4 (17%) did not change the P-R length. Although atrial pacing-induced Mobitz I A-V block may indicate a latent A-V nodal conduction abnormality in some cases, its demonstration does not necessarily predict the occurrence of spontaneous advanced A-V block. Exercise should not be restricted in these patients on the basis of such a finding during a pacing study.