Serum isoamylase activities in cystic fibrosis patients, determined by an inhibitory assay.

Serum isoamylase activities were determined in patients with either cystic fibrosis (CF) or celiac disease and in age-matched healthy children by means of an inhibitory assay suitable for routine application. The percentage pancreatic isoamylase (PIA) activity was significantly decreased in CF patients when compared with that of patients with celiac disease. Cystic fibrosis patients with steatorrhea had lower absolute values of PIA activity and higher values of salivary isoenzyme activity than control individuals. There was no overlapping between values obtained from CF patients and either celiac patients or healthy individuals. These results suggest that determination of PIA activity may be a useful adjunct test for the diagnosis of CF in patients with steatorrhea.

The importance of erythroid expansion in determining the extent of apoptosis in erythroid precursors in patients with beta-thalassemia major.

Beta-thalassemia major is characterized by ineffective erythropoiesis leading to severe anemia and extensive erythroid expansion. The ineffective erythropoiesis is in part due to accelerated apoptosis of the thalassemic erythroid precursors; however, the extent of apoptosis is surprisingly variable. To understand this variability as well as the fact that some patients undergoing allogeneic marrow transplantation are resistant to the myeloablative program, we attempted more quantitative analyses. Two groups of patients totaling 44 were studied, along with 25 healthy controls, and 7 patients with hemolysis and/or ineffective erythropoeisis. By 2 flow cytometric methods, thalassemic erythroid precursors underwent apoptosis at a rate that was 3 to 4 times normal. Because thalassemic marrow has between 5- to 6-fold more erythroid precursors than healthy marrow, this translated into an absolute increase in erythroid precursor apoptosis of about 15-fold above our healthy controls. In searching for the causes of the variability in thalassemic erythroid precursor apoptosis, we discovered tight direct correlations between the relative and absolute extent of apoptosis and the extent of erythroid expansion as measured either by the absolute number of marrow erythroid precursors or by serum soluble transferrin receptor levels. These results could mean that the most extreme rates of erythroid proliferation lend themselves to cellular errors that turn on apoptotic programs. Alternatively, extreme rates of erythroid hyperplasia and apoptosis might be characteristic of more severely affected patients. Lastly, extreme erythroid hyperplasia could generate such numbers of apoptotic erythroid precursors that marrow macrophages are overwhelmed, leaving more apoptotic cells in the sample.

Prueba respiratoria con un isotopo estable en ninos con alteraciones del ciclo de los acidos biliares. / Stable isotope breath test in children with changes of the biliary acids cycle

Con el acido glicolico 13C se puede analizar la deconjugacion bacteriana intestinal de los acidos biliares conjugados.Luego de la ingesta de aquel, se evidencia un exceso del 13C en el dioxido de carbono del aire espirado, cuando esta incrementada su deconjugacion, ya sea por sobredesarrollo bacteriano en el intestino delgado o como consecuencia de una reseccion ileal.Se estudiaron 4 ninos con distintas patologias del tracto digestivo en los que midio, mediante espectrometria de masas, el 13C en el aire espirado luego de administrar acido glicocolico enriquecido con dicho isotopo. En uno de los pacientes se demostro un ascenso significativo; en los otros los valores se mantuvieron similares a los basales. Se describe el desarrollo de un metodo de diagnostico en aire respiratorio, en el que se utiliza un isotopo estable del carbono.Su caracteristica sobresaliente es la ausencia de irradiacion, hecho significativo, en especial, por la edad de los pacientes estudiados