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Biomedical subjects

E A Rachmilewitz

Publications and source records attributed to E A Rachmilewitz.

At least 19 recordsLinked to original sources
PubMed1979

"Lysosomal" enzyme activities in red blood cells of normal individuals and patients with homozygous beta-thalassaemia.

Four hydrolases, beta-galactosidase, beta-glucuronidase, beta-N-acetylglucosaminidase and acid phosphatase were examined in red blood cells (RBC) of normal donors and patients with homozygous beta-thalassaemia. Highly sensitive fluorimetric substrates were used to determine the specific activities of these enzymes. In order to avoid contamination by lysosomal activities derived from white blood cells (WBC), the mature RBV were separated from other blood elements by cellulose chromatography. The hydrolase activities in normal RBC were detected only in their plasma membranes and were found to be considerably lower than in WBC or platelets. In thalassaemic RBC, hydrolase activities were present in both plasma membranes and in the soluble fraction. The normoblast fraction contributed most of the hydrolase activity found in these preparations, suggesting the presence of lysosomal particles in thalassaemic RBC. No differences in the enzymatic activities were found when purified membranes of mature RBC from thalassemic and normal preparations were compared. The origin and roles of these hydrolytic enzymes in normal and thalassaemic RBC membranes are not known.

Acetylglucosaminidase↗
PubMed1979

Intracerebral tumor and diffuse central nervous system infiltration complicating acute myelogenous leukemia.

An intracerebral space occupying lesion was found in a 20-year-old woman with acute myelogenous leukemia (AML) when she was in complete hematological remission. Computerized tomography of the brain demonstrated the tumor in the roof of the third ventricle and its subsequent resolution after cranial irradiation and intraventricular cytosine-arabinoside. This form of central nervous system complication in AML has not been previously reported.

Adult↗
PubMed1979

Quantitative studies of ferritinlike iron in erythrocytes of thalassemia, sickle-cell anemia, and hemoglobin Hammersmith with Mössbauer spectroscopy.

By using the technique of recoil-free absorption (Mössbauer effect) in iron, we found large amounts of iron, yielding a well-defined spectrum different from that of oxy- or deoxyhemoglobin, in whole erythrocytes of 13 patients with beta-thalassemia major and intermedia, 3 with hemoglobin H disease, 2 with sickle-cell anemia, and 1 with unstable hemoglobin Hammersmith. The Mössbauer spectra at various temperatures of this additional component of iron were found to be identical to spectra obtained from isolated ferritin or hemosiderin. This observation, together with additional arguments, strongly suggests that the compound responsible for the additional subspectrum is an iron storage protein, ferritin or hemosiderin. The amounts of ferritinlike iron were comparable to those of hemoglobin iron and were particularly large in reticulocytes. No ferritinlike iron was detected in patients with severe autoimmune hemolytic anemia and pernicious anemia. The large quantities of ferritinlike iron in hemoglobinopathies are probably due to intracellular hemoglobin denaturation and the consequent release of excess iron.

Anemia↗
PubMed1979

Phagocytosis of nucleated and mature beta thalassaemic red blood cells by mouse macrophages in vitro.

Physiological or experimental decrease in sialic acid (SA) content on the red blood cell (RBC) membrane is believed to play an important role in the recognition of these cells by macrophages. Since there is a 20-30% decrease in the SA content on the membrane of thalassaemic RBC, the interaction between macrophages and these RBC was studied in vitro. Using mouse peritoneal macrophages, it was found that these macrophages 'recognize' and phagocytize thalassaemic RBC while RBC from normal donors are hardly phagocytized. The average level of phagocytosis of thalassaemic RBC from splenectomized patients was found to be 22-fold higher than that of RBC from normal donors. The phagocytized cells consisted of both mature and nucleated RBC. Mouse peritoneal macrophages seem to be a useful in vitro system for the study of the accelerated sequestration and shortened life span of thalassaemic RBC.

Animals↗
PubMed1979

Acute promyelocytic leukemia in childhood. Report of a case with a review of the literature.

A rare case of acute promyelcytic leukemia (APL) is reported in a 7-year-old boy. The patient displayed the typical features of APL including impaction of the marrow with promyelocytes, marked elevation of the serum vitamin B12 and transcobalamin I levels and a hemorrhagic diathesis. The bleeding diathesis in the case was due to thrombocytopenia, and there was no evidence for disseminated intravascular coagulation.

Bone Marrow↗
PubMed1979

Globin synthesis in bone marrow cells of patients with sickle cell anemia and beta O-thalassemia: contamination of the beta-chain with non-globin proteins.

Chromatographic separation of labeled globin chains was performed in stroma-free hemolysates prepared from peripheral blood and bone marrow cells of 11 patients with beta O-thalassemia and 2 patients with sickle cell anemia. A small radioactivity peak, slightly preceding the beta-chain and more prominent in bone marrow cells, was often observed. This peak, which represents synthesis of non-globin proteins, did not exceed 5% of the radioactivity incorporated in the alpha-chain. It is concluded that contamination of the beta-chain with non-globin proteins undoubtedly occurs, but its extent is insufficient to explain the different synthetic ratios which have been repeatedly observed in peripheral blood and in bone marrow cells of patients with heterozygous beta-thalassemia.

Anemia, Sickle Cell↗
PubMed1978

Left ventricular function in beta-thalassemia and the effect of multiple transfusions.

Left ventricular performance was studied in 23 young patients with severe chronic anemia due to beta-thalassemia major and intermedia. The patients were divided into three groups according to the number of blood transfusions they had received. The left ventricle (LV) was enlarged in patients who had not received blood and larger still in patients who had received multiple transfusions. Echocardiography and systolic time interval measurements showed that systolic function of the LV was good in all the patients and that there was no statistical difference in systolic function in patients who had and those who had not received multiple transfusions. Heart rate was increased in the latter group. Stroke index and cardiac index were high, especially in patients in Group 3. The diastolic closure rate (EF slope) of the anterior mitral leaflet and its amplitude of movement were increased, but less so in Group 3; this may reflect an alteration in diastolic LV distensibility. The results indicate that despite the presence of cardiomegaly and severe clinical congestive heart failure, LV performance is well preserved in patients with beta-thalassemia, even in those who have received repeated blood transfusions. Clinical cardiac failure is the consequence of volume overload and abnormal chamber compliance. There was no evidence in this of a congestive cardiomyopathy.

Adolescent↗
PubMed1978

Non-specific serum iron in thalassaemia: an abnormal serum iron fraction of potential toxicity.

Iron binding in the sera of 35 patients with beta thalassaemia major and intermedia was studied. In patients receiving regular blood transfusions since infancy transferrin was completely saturated and about 2.7--7.1 mumol/l of the serum iron could be removed by dialysis or ultrafiltration in the presence of a chelating agent or by filtration on DEAE-Sephadex-catecholdisulphonic acid columns. In contrast, less than 1.0 mumol/l of transferrin bound iron was removed when subjected to the same procedures. The non-specific iron of thalassaemic sera could no longer be demonstrated after incubation with normal serum. These findings indicate that non-specific iron is a chelatable with normal serum. These findings indicate that non-specific iron is a chelatable compound which is readily available for transferrin binding. In view of the known toxicity of unbound iron, its identification in thalassaemic sera might be of relevance to the pathogenesis of tissue damage and the protective effect of iron chelating therapy in this disease.

Adolescent↗
PubMed1978

Gonadotrophin, thyrotrophin and prolactin reserve in beta thalassaemia.

Gonadotrophin (Gn), thyrotrophin (TSH) and prolactin (PRL) reserve was evaluated in patients (aged 12-26 years old) with beta thalassaemia. Abnormalities were detected in Gn reserve only. When compared with young adult controls, three of the four female patients and one of the two adult males had markedly impaired Gn responses to LH-releasing hormone (LHRH). Of the five prepubertal males, one had no Gn rise following LHRH, while responses in the other four patients were comparable to those in boys with delayed puberty. Only one adult male had an exaggerated LH response to LHRH. TSH and PRL dynamics were normal. No correlation could be found between the severity of the disturbance in the gonadal axis and the total number of blood transfusions. Our findings correlate best with the severity of the disease process itself.

Adolescent↗
PubMed1978

Characterization of the normoblast population in beta-thalassaemic blood by rapid-flow cytofluorometry.

Samples of peripheral blood from patients with beta-thalassaemia major which contained significant numbers of nucleated normoblasts were stained with acridine orange and analyzed with rapid-flow cytofluorometry. The pyknotic normoblast-nuclei gave less green 'DNA' fluorescence than the (diploid) leucocytes and constituted a separate, distinct subpopulation. Mean values of the fluorescence intensities and standard deviations as displayed by multichannel analyses gave a numerical value for normoblasts with regard to their maturation stages. These mean values correlated with the differential counts of 'early and late' normoblasts in the light microscope under rigidly standardized conditions. Rapid-flow cytofluorometry thus provides an objective and quantitative way to monitor and define peripheral blood normoblast populations as a measure of the severity of 'erythropoietic stress'.

Adolescent↗
PubMed1978

Blood group phenotypes and the origin of sickle cell hemoglobin in Sicilians.

As an approach to investigating the origin of sickle cell hemoglobin (hemoglobin S) in white persons of Sicilian ancestry, two groups of native Sicilians were tested for blood group evidence of African admixture. Among 100 unrelated Sicilians, the phenotypes cDe(Rho) and Fy(a-b-), and the antigens V(hrv) and Jsa, which are considered to be African genetic markers, were detected in 12 individuals. Among 64 individuals from 21 families with at least one known hemoglobin S carrier, African blood group markers were detected in 7 (11%). These findings indicate that hemoglobin S is only one of multiple African genes present in contemporary Sicilian populations. The occurrence of hemoglobin S in white persons of Sicilian ancestry is considered to be a manifestation of the continuing dissemination of the original African mutation.

Black People↗
PubMed1978

Hydrolase activities in normoblasts of beta-thalassemic patients.

A physiological role for glycosidases in cell membranes has been suggested. Therefore the activities of four glycosidases--beta-galactosidase, beta-glucoronidase, N-acetyl-beta-glucosaminidase and acid phosphatase--were examined in normoblasts and membranes of red blood cells (RBC). The enzymatic assays were based on the hydrolysis of fluorimetric 4-methylumbelliferone from the enzyme substrate. In order to avoid contamination by lysosomal activities derived from RBC, the mature RBC and normoblasts obtained from normal controls and thalassemic patients were separated from other blood elements by cellulose chromatography. The cells were disrupted and lysed by freezing and thawing hypotonic solution. Higher enzymatic activities were found in preparations from thalassemic patients than from normal subjects. With a sucrose density gradient, further separation of normoblasts from RBC membranes was obtained, indicating that the normoblast fraction contributed most of the high specific activity found in the thalassemic preparation. It was concluded that relatively high glycosidase activities are present in normoblasts of thalassemic patients. Lower but significant activities were detected in RBC membranes of normal control subjects and thalassemic patients.

Acetylglucosaminidase↗