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Spleens collected from 85 consecutive autopsies of AIDS patients (mean age 37 years) were studied. Splenomegaly, observed in 59 cases (69.4%), does not statistically correlate with life style and blood transfusions. Eleven very large spleens (over 890 g) were associated with opportunistic infections (i.e.: mycobacteria, true fungi and rochalimaea). The histological pattern was characterized by marked lymphoid depletion of the white pulp and--in 67 cases (89.4%)--packing of the pulp cords by macrophages engulfed of brown pigment which was strongly positive to the Perls reaction for ferric iron. The contemporary presence of Perls positive and p24 immunoreactive material was diffusely observed in the cytoplasm of splenic macrophages, also positive to the alkaline tetrazolium reaction. The same was observed in the cytoplasm of monocytes/macrophages of lung and brain (in 5 out of 5 patients with splenomegaly > 600 g, randomly selected). We believe that our findings deal with the formation of a haemoglobin--p24 complex and are in keeping with recent data which suggest the formation of disulphide bonds between viral proteins and haemoglobin.

Differences in erythrocyte distribution on Ficoll-Sodium Metrizoate discontinuous density gradient were evaluated between adult males and females. Testosterone and androstenedione plasma levels were tested in males, oestradiol, progesterone and prolactin in both males and females. Female group showed a much higher proportion of lighter younger erythrocytes than males, while males showed higher proportion of denser older cells. Positive correlation was found between young cell percent and oestradiol level, both in males and females, but no correlation was found with androgen hormones.

Determinations of erythrocyte glucose-6-phosphate dehydrogenase, pyruvate kinase and glucose-phosphate isomerase activities have been carried out in jaundiced and non-jaundiced newborn infants at birth and after 5 days of life. Only hyperbilirubinemias of unknown etiology have been considered. Previous investigations have demonstrated that erythrocyte age dependent enzyme activities decrease in the healthy newborn during the first week of life. Following the results of the present paper, jaundiced newborns do not show such a decrease, since a statistically significant difference between paired data of glucose-6-phosphate dehydrogenase and pyruvate kinase in jaundiced and non-jaundiced newborns have been found. It is likely that the lack of decrease of enzyme activities in the jaundiced infants depend upon the loss of oldest red cells with low glucose-6-phosphate dehydrogenase and pyruvate kinase. Our observation suggests the occurrence of a slight hemolysis in newborn infants with hyperbilirubinemia of unknown etiology.

Human red blood cells have been separated into five fractions of differing mean ages by centrifugation through a density gradient of Ficoll-Triosil layers. The procedure is carried out on 0.3-0.6 ml packed erythrocytes, with good reproducibility and significant difference among the fractions. The separation is achieved using small ultracentrifuge rotors of common use, at 37,000 g. The enzymatic activity of glucose-6-phosphate dehydrogenase (G-6-PD) is estimated to test the difference in the mean age of the isolated fractions.

A case of acquired dyserythropoietic anemia is described in a sixty-six year old patient: is characterized by a very considerable pancitopenia, and by the presence in the bone-marrow of notable morphologic atipia both in erythroblastic line and in granulocitopoietic one. The iron kinetics and erythrocitic surviving are highly altered. The citochimic study points out the presence of myelocites with perossidasis-deficit and the presence of PAS positive erythroblasts. These data indicate metabolic anomalies that seem to localize the primitive deficit in the stem-cells.

In a group of 36 homozigous beta-thalassaemic children we studied the effect of splenectomy on hemorheologic characteristics. The aim of the work was to evaluate the importance of such operation either on anemia or on erythrocyte deformability. Whole blood viscosity was measured with a Brookfield Microviscometer (LVT) and erythrocyte deformability was evaluated with the erythrocyte filtration technique using policarbonate membranes. The more the erythrocyte deformability decreases, the more the erythrocyte filtration rate decreases. Our data show that splenectomized children, have worse hemorheologic characteristics according to the longer survival time of pathological red blood cells in spite of their reduced deformability. This behaviour can be modified only by blood transfusion that we have seen to be able to reduce whole blood viscosity and to increase erythrocyte filtration rate in splenectomized children. We think that splenectomy must be delayed as long as possible so that hemodinamyc conditions cannot be worsened. An hemorheologic monitorage could be useful for diagnostic and prognostic evaluations both in splenectomized and not splenectomized children.

In two groups of subjects (young and elderly), the red blood cell (RBC) deformability was examined determining the filtration time by means of two different methods (filtration of whole blood and filtration of RBC suspension with hematocrit adjusted at 20%, respectively). In addition, the DFE (Debit de filtration erythrocytaire), an indirect index of capillary blood flow, was mathematically derived. Since the filtration times appear to be positively correlated with age, it is conceivable that in the elderly, erythrocytes are less deformable than in the young, and that this change may impair both capillary blood flow and tissue oxygen delivery; this alteration is further emphasized when the relationship between whole blood filtration time and hematocrit is taken into account.

Separation of erythrocytes into fractions of different age was carried out by the method of discontinuous gradient. Five fraction of various specific density were prepared and in each fraction age dependent enzyme activities PK and G-6-PD were assayed. The erythrocytes from cord blood and from newborn 4-5 days old were studied. The results demonstrate the correlation between density and erythrocyte age in both cord blood and blood from newborns. However, 4-5 days old demonstrate a shift of various populations toward fractions of higher density.

Anaemia is common in renal insufficiency and has various causes: 1) depressed marrow production of red cells, probably due to reduced production of erythropoietin, though the possibility of direct marrow inhibition on the part of uraemic toxins cannot be ruled out, together with iron deficiency, as occurs in prolonged dialysis management; 2) greater red cell destruction attributable to extraglobular factors and other mechanisms (microangiopathy, drugs, etc.); 3) greater blood loss following thrombocytopenia, reduced platelet adhesivity and agglutinability, dialysis. The main premisses on which the treatment of anaemia of uraemic patients is based are discussed.

The erythrocyte activities of glucose 6-phosphate dehydrogenase, pyruvate kinase and glucose phosphate isomerase decrease during the first days of life. Furthermore the level of these enzymatic activities is higher in newborn infants with higher percentage of carboxyhemoglobin. It is likely that a premature and rapid fall of reticulocytes causes a decrease in enzymatic activities sensitive to aging and that the higher hemolysis can represent a disappearance of oldest erythrocytes which present lower enzymatic activities. These data therefore confirm the block in erythropoiesis in the first hours of life.