Competing models for the analysis of red cell survival obtained with 51Cr labelling technique.

A computer program for the analysis of 51Cr labelled red cell survival data was used in 84 patients and 8 normal subjects to estimate the parameters of 7 competing models derived from different hypotheses of the red cell destruction process. The purpose was to establish the optimal complexity of a red cell survival model to be used. Senescence or random destruction were the most common identified patterns of red cell death (79% of the cases). Models assuming different levels of death probability according to the age of cells, or 2 populations of cells with different death probabilities, were selected in 21% of the cases. These latter patients were characterized by the lowest values of MRCL. The conclusion of the work was that an automatic procedure for selecting the best model of red cell destruction is necessary when information concerning the mechanism of red cell death is required. For the more practical aim of obtaining an accurate measurement of the MRCL, the minimal set of competing models should account of at least 2 different populations of cells in addition to the random or senescence destruction models.

Juvenile idiopathic haemochromatosis: a life-threatening disorder presenting as hypogonadotropic hypogonadism.

It is generally believed that idiopathic haemochromatosis is exclusively a disease of middle age, affecting primarily men. We describe here four cases of idiopathic haemochromatosis having onset of symptoms before or around the age of 20 years. Other similar cases have previously been reported. In this juvenile form, males and females appear to be equally affected. These subjects may have a history of unexplained abdominal pain, present with hypogonadotropic hypogonadism, and, unless proper treatment is started, die early because of cardiac dysfunction. In this regard, their clinical course is very similar to that of well-transfused thalassemia major. Thus, early diagnosis is even more important in the juvenile form than in the adult form of idiopathic haemochromatosis. We suggest that evaluation of body iron stores should be performed as a screening procedure in young subjects with hypogonadotropic hypogonadism and/or cardiac dysfunction.

Meningeal leukemia following lymphoid blast crisis in chronic myeloid leukemia: therapeutic implications.

Five of 40 patients with chronic myeloid leukemia (CML) had lymphoid blast crisis and 4 of them achieved complete remission of metamorphosis with vincristine and prednisone. While in hematologic remission, two of these subjects developed meningeal leukemia. Clinical and biologic data indicated that the course of the disease after lymphoid blast crisis was very similar to that of acute lymphoblastic leukemia (ALL). It is suggested that patients with CML who develop lymphoid blast crisis should be treated with an intensive therapeutic protocol including early prevention of meningeal leukemia.

Quantitative evaluation of erythropoietic activity in dysmyelopoietic syndromes.

Based on the morphological appearances of the bone marrow and peripheral blood, 43 patients with dysmyelopoietic syndromes were categorized into four types: refractory anaemia with excess of blasts, chronic myelomonocytic leukaemia, primary acquired sideroblastic anaemia and refractory anaemia with cellular marrow, without excess of blasts and/or ring sideroblasts. Ferrokinetics allowed three distinct groups of patients to be defined. All cases of refractory anaemia with excess of blasts and chronic myelomonocytic leukaemia were classified in the same group. They were characterized by relative marrow failure and had a high likelihood of developing acute leukaemia. At the other end of the spectrum, individuals with primary acquired sideroblastic anaemia had high erythropoietic activity which was largely ineffective. They had a benign clinical course without evidence of leukaemic transformation. In the middle group, in terms of erythropoietic activity, lay patients with refractory anaemia with cellular marrow and a few individuals with primary acquired sideroblastic anaemia. Their clinical course and risk of developing acute leukaemia were intermediate between the other two groups. These findings indicate that separate entities may exist within the spectrum of dysmyelopoietic syndromes. In clinical practice, they may be recognized by morphological studies and other simple laboratory means.