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Biomedical subjects

B Lubin

Publications and source records attributed to B Lubin.

At least 145 records · Page 8Linked to original sources
PubMed1981

Abnormalities in membrane phospholipid organization in sickled erythrocytes.

In contrast to the wealth of information concerning membrane phospholipid asymmetry in normal human erythrocytes, very little is known about membrane phospholipid organization in pathologic erythrocytes. Since the spectrin-actin lattice, which has been suggested to play an important role in stabilizing membrane phospholipid asymmetry, is abnormal in sickled erythrocytes, we determined the effects of sickling on membrane phospholipid organization. We used two enzymatic probes: been venom phospholipase A2 and Staphylococcus aureus sphingomyelinase C, which do not penetrate the membrane and react only with phospholipids located in the outer leaflet of the bilayer. Our results suggest that the distribution of glycerophospholipids within the membrane of sickled cells is different from that in nonsickled cells. Compared with the normal erythrocyte, the outer membrane leaflet of the deoxygenated, reversibly sickled cells (RSC) and irreversibly sickled cells (ISC) was enriched in phosphatidyl ethanolamine in addition to containing phosphatidyl serine. These changes were compensated for by a decrease in phosphatidyl choline in that layer. The distribution of sphingomyelin over the two halves of the bilayer was unaffected by sickling. In contrast to ICS, where the organization of phospholipids was abnormal under both oxy and deoxy conditions, reoxygenation of RSC almost completely restored the organization of membrane phospholipids to normal. These results indicate that the process of sickling induces an abnormality in the organization of membrane phospholipids to normal. These results indicate that the process of sickling induces an abnormality in the organization of membrane lipids in RSC which become permanent in ISC.

Anemia, Sickle Cell↗
PubMed1981

A Hebrew version of the Depression Adjective Check Lists.

In order to develop a Hebrew version of the Depression Adjective Check Lists (DACL) for use in research, the lists were translated by linguists and the adequacy of the translations determined. Reliability (split-half, alternate form, internal consistency, and test-retest) of translated lists E, F, and G were sufficiently high in the case of the first three and sufficiently low in the case of test-retest reliability of the state DACL. Concurrent validity was determined in three separate samples: correlations with (a)a 7-point self-rating scale of depression, (b)the MMPI-D Scale, (c)the Bradburn Scale of Psychological Well-being, the Cantril Self-anchoring Striving Scale, and the Katz Social Adjustment Symptom Subscale, and demographic variables. Magnitude of correlations were sufficiently high and in the expected direction. Also, correlations with part scores of the Bradburn Scale of Well-being demonstrated the discriminant validity of the Hebrew version of the DACL.

Adult↗
PubMed1981

Sickled erythrocytes accelerate clotting in vitro: an effect of abnormal membrane lipid asymmetry.

A membrane lipid abnormality induced by sickling and found as a permanent alteration in the irreversibly sickled cell (ISC) is the rearrangement of phosphatidyl ethanolamine (PE) and phosphatidyl serine (PS) from the inner to the exterior side of the lipid bilayer. Since PS can provide a catalytic surface for the binding of blood coagulation factors and thus can exhibit procoagulant activity, we investigated the influence of oxy and deoxy reversibly sickled cells (RSC) ass well as ISC on clotting in vitro. Red blood cells (RBC), as the source of phospholipid, were added to platelet-poor citrated plasma containing Russell's viper venom (RVV) and clotting time was measured after recalcification. The clotting time after addition of normal RBC and oxy-RSC was similar to the saline blank (100 sec). In contrast, both oxy-ISC and deoxy completely sickled RSC shortened clotting time by 30%. Using liposomes prepared with identical phospholipid composition to the outer lipid leaflet of either normal RBC, RSC or ISC clotting times similar to those with intact cells were achieved. Since the liposomes did not contain protein, accentuation of clotting appears to be related to abnormal phospholipid organization, in particular to the abnormal exposure to aminophospholipids on the outer surface of the membrane. This abnormality may contribute to the pathogenesis of the vaso-occlusive episode in sickle cell anemia.

Anemia, Sickle Cell↗
PubMed1981

The diagnosis of iron deficiency anemia in sickle cell disease.

We determined the prevalence and optimal methods for laboratory diagnosis of iron deficiency anemia in patients with sickle cell disease. Laboratory investigations of 38 nontransfused and 32 transfused patients included transferrin saturation, serum ferritin, mean corpuscular volume (MCV), and free erythrocyte protoporphyrin (FEP). Response to iron supplementation confirmed the diagnosis of iron deficiency anemia in 16% of the nontransfused patients. None of the transfused patients were iron deficient. All iron-deficient patients (mean age 2.4 yr) had a low MCV, serum ferritin less than 25 ng/ml, transferrin saturation less than 15%, and FEP less than 90 micrograms/dl RBC. Following therapy, all parameters improved and the hemoglobin concentration increased greater than 2 g/dl. A serum ferritin below 25 ng/ml was the most reliable screening test for iron deficiency. There were 13% false positive results with transferrin saturation, 3% with MCV, and 62% with FEP. FEP values correlated strongly with reticulocyte counts. The high FEP was in part due to protoporphyrin IX and not completely due to zinc protoporphyrin, which is elevated in iron deficiency. We conclude that iron deficiency anemia is a potential problem in young nontransfused sickle cell patients. Serum ferritin below 25 ng/ml and low MCV are the most useful screening tests.

Adolescent↗
PubMed1980

Survey of training programs in clinical neuropsychology.

Reported the results of a survey of the membership of the International Neuropsychology Society with regard to patterns of training in clinical neuropsychology. Considerable variations in pre- and postdoctoral training and internship programs were found.

Education, Medical, Graduate↗
PubMed1980

Cord blood screening for hemoglobin abnormalities by thin layer isoelectric focusing.

Hemoglobin variants can be successfully identified in cord blood samples. The methods most commonly used include cellulose acetate (CAC) and citrate agar (CAG) electrophoresis. Recently thin layer isoelectric focusing (TLIF) has been shown to be an excellent method for identifying hemoglobin variants. To determine the applicability of TLIF for cord blood screening, we compared the results of 835 samples obtained by TLIF with that obtained by CAC, CAG, and the combination of both CAC and CAG. In 100 of these samples we detected an abnormal hemoglobin pattern using TLIF. In contrast, we detected only 80 abnormal samples by CAC, 70 by CAG, and 80 by using the combination of CAC and CAG. Due to the increased resolution provided by TLIF, we correctly diagnosed two sickle cell trait samples by TLIF that were incorrectly suspected to be homozygous for sickle cell disease by CAC and CAG. We identified 41 samples containing Bart's hemoglobin by TLIF in contrast to only 21 using CAC and 14 using CAG. The time and cost of TLIF was comparable to that using the combination of both methods. We, therefore, conclude that TLIF is the method of choice for cord blood screening.

Anemia, Sickle Cell↗
PubMed1979

Erythrocyte membrane lipid reorganization during the sickling process.

In order to study possible alterations in membrane lipids during sickling, we have measured the difference in susceptibility to lipid peroxidation, binding of trinitrobenzenesulfonic acid (TNBS) to aminophospholipids, and fatty acid uptake in cells containing sickle haemoglobin under aerobic and anaerobic conditions. We have also examined TNBS binding in irreversibly sickled cells in an attempt to evaluate the permanent effects of any such alterations. We found that when erythrocytes were sickled by deoxygenation, the susceptibility to lipid peroxidation and binding of TNBS to aminophospholipids was markedly increased, while normal control cells showed no change. These effects appeared to be specific for the sickled state rather than a nonspecific consequence of cell age or the concentration of sickle haemoglobin within the cell. In contrast, fatty acid incorporation into membrane phospholipids, representing potential lipid renewal, was decreased in the sickled state. Cell fractions enriched in irreversibly sickled cells showed increased TNBS labelling in air and only modest rises with anoxia. Taken together, these data imply a rearrangement of membrane lipids during the sickling process and suggest a permanent reorganization of membrane lipids in the irreversibly sickled cell.

Aerobiosis↗