Search PubMed⌕ Search

Biomedical subjects

B Lubin

Publications and source records attributed to B Lubin.

At least 109 records · Page 6Linked to original sources
PubMed1985

Depression Adjective Check Lists: Spanish, Hebrew, Chinese and English versions.

Data are presented on the translation, reliability, concurrent validity, and norms of the Spanish, Hebrew, and Chinese versions of three equivalent forms of the Depression Adjective Check Lists, and comparisons with the English version are made. Reliability estimates (split-half, alternate form, and internal consistency) for the four versions are quite similar in magnitude (.79 to .94). Concurrent validity was determined in each case by means of correlations with translated versions of a self-rating scale of depression, the Bradburn Scale, the Cantril Self-Anchoring Striving Scale, and the Katz Psychophysiologic-psychosomatic Symptom Scale. The English and Hebrew norms are based upon national probability sampling.

Cross-Cultural Comparison↗
PubMed1985

Performance of bilingual subjects on Spanish and English versions of the Depression Adjective Check Lists.

To study the performance of bilingual subjects on the Spanish and English versions of the Depression Adjective Check Lists (DACL), 27 males and 34 females completed the three forms of the DACL (E, F, and G), each of which was printed half in Spanish and half in English. Order of language was counterbalanced. No significant effects either for language or sex of subject were found. These findings, together with high correlations (.84 to .89) between the Spanish and English halves of each list, support the use of the Spanish version of the DACL in research with Spanish-speaking subjects from the southwestern United States.

Depressive Disorder↗
PubMed1985

Increased adherence of sickled and phosphatidylserine-enriched human erythrocytes to cultured human peripheral blood monocytes.

The precise mechanism by which sickle erythrocytes (RBC) are removed from the circulation is controversial, although it is possible that enhanced recognition of these cells by circulating mononuclear phagocytes could contribute to this process. We investigated this possibility by interacting sickle cells with cultured human peripheral blood monocytes. Our results show that both irreversibly sickled cells (ISC) and deoxygenated reversibly sickled cells (RSC) had a higher avidity for adherence to monocytes than did oxygenated sickle and normal RBC. ISC were the most adherent cell type. Adherence of RSC to monocytes was found to be reversible; reoxygenation of deoxygenated RSC resulted in a significant decrease in RSC--monocyte adherence. Concomitant with alterations in sickle RBC adherence were alterations in the organization and bilayer distribution of membrane phospholipids in these cells. Specifically, enhanced adherence was associated with increased exposure of RBC membrane outer leaflet phosphatidylserine (PS) and phosphatidylethanolamine, whereas lack of adherence was associated with normal patterns of membrane phospholipid distribution. To investigate the possibility of whether the exposure of PS in the outer membrane leaflet of these cells might be responsible for their recognition by monocytes, the membranes of normal RBC were enriched with the fluorescent PS analogue 1-acyl-2[(N-4-nitro-benzo-2-oxa-1,3-diazole)aminocaproyl]-phosphatidy lse rine (NBD-PS) via transfer of the exogenous lipid from a population of donor phospholipid vesicles (liposomes). RBC enriched with NBD-PS exhibited enhanced adherence to monocytes, whereas adherence of RBC enriched with similar amounts of NBD-phosphatidylcholine (NBD-PC) was not increased. Furthermore, preincubation of monocytes with PS liposomes resulted in a approximately 60% inhibition of ISC adherence to monocytes, whereas no inhibition occurred when monocytes were preincubated with PC liposomes. These findings strongly suggest that erythrocyte surface PS may be a ligand recognized by receptors on human peripheral blood monocytes and that abnormal exposure of PS in the outer leaflet of the RBC membrane, as found in sickle RBC, might serve to trigger their recognition by circulating monocytes. Our results further suggest that abnormalities in the organization of erythrocyte membrane phospholipids may have significant pathophysiologic implications, possibly including shortened cell survival.

Anemia, Sickle Cell↗
PubMed1985

Effect of hydrogen peroxide exposure on normal human erythrocyte deformability, morphology, surface characteristics, and spectrin-hemoglobin cross-linking.

To further define the conditions for forming spectrin-hemoglobin cross-linking in human erythrocyte membranes and to examine its possible effects on membrane function, we incubated normal human erythrocytes for up to 3 h in concentrations of H2O2, varying from 45 to 180 microM, in an azide phosphate buffer, pH 7.4. The chemical changes observed indicated that methemoglobin formation occurred early and at a low concentration (45 microM). Morphologic changes characterized by increased echinocyte formation occurred in a dose-dependent fashion. In addition, decreased cell deformability commensurate with increased membrane rigidity was found. Finally, an increase in cell recognition as determined by monocyte phagocytosis and adherence in vitro, as well as decreased phosphatidylcholine accessibility to bee venom phospholipase A2, was found in H2O2-treated erythrocytes compared with controls. Both of these latter changes were closely correlated with the extent of spectrin-hemoglobin cross-linking. In addition to these protein-mediated interactions, lipid peroxidation also occurred after H2O2 exposure, as shown by generation of fluorescent amino propene derivatives. The addition of the antioxidant, butylated hydroxytoluene, decreased the fluorescent derivatives, but did not prevent the effects on membrane function. This suggests that lipid peroxidation, though present, was not necessary for the membrane changes found. In contrast, spectrin-hemoglobin aggregation and the alterations in membrane function were completely prevented by prior exposure of the erythrocytes to carbon monoxide.

Carbon Monoxide↗
PubMed1985

Plasma membrane phospholipid organization in human erythrocytes.

By weight, phospholipids make up approximately 25% of the plasma membrane of mature human erythrocytes. The four major phospholipid species present in the membrane (PC, PE, PS, and SM) are distributed asymmetrically across the bilayer leaflet resulting in an enrichment of choline-phospholipid (PC and SM) in the outer leaflet and of amino-phospholipid (PE and PS) in the cytoplasmic leaflet. This asymmetric organization is preferentially maintained through complex, and at present, poorly understood noncovalent interactions between specific membrane lipids and proteins (in particular, a stabilizing role for the skeletal protein spectrin and band 4.1 have been implicated), although other considerations such as phospholipid net charge, size, and degree of acyl chain unsaturation may also be involved. In certain red cell pathologies, or following experimental manipulation, there is a partial loss of this asymmetry (summarized in Tables XVI, XVII) often resulting in increases in the outer leaflet content of amino-phospholipids and subsequent expression of altered membrane surface properties. Some of these abnormal properties may have pathophysiologic consequence; indeed, red cell membranes displaying increased levels of surface amino-phospholipids have been shown to be potent procoagulants and demonstrate enhanced intermembrane interactions with both model (liposomes) and biologic (mononuclear phagocytes) membranes. Redistribution of membrane phospholipids may not occur homogeneously throughout an entire leaflet but may be restricted to specific membrane regions. These studies strongly suggest that the maintenance of phospholipid asymmetry in human red cell membranes is not a trivial event but probably represents a homeostatic mechanism, the failure of which may lead to alterations in normal erythrocyte functions, and ultimately, survival.

Blood Coagulation↗
PubMed1984

Mechanism of inhibition of sickling by dimethyl adipimidate. Effects of intertetramer cross-linking.

Dimethyl adipimidate (DMA), an effective antisickling agent in vitro, reacts with free amino groups producing chemically modified and cross-linked molecules. In this report, we have investigated the effect of cross-linked hemoglobin tetramers on sickle hemoglobin polymerization. Since the extent of cross-linking is pH-dependent, we first compared the solubilities of deoxygenated hemolysates prepared from sickle cells previously treated with dimethyl adipimidate at either pH 7.4 or 8.4. The solubility of the hemolysate increased from 18.6 +/- 0.8 g/dl in the untreated sample to 20.9 +/- 1.5 g/dl (pH 7.4) and to 25.4 +/- 3.0 g/dl (pH 8.4) after dimethyl adipimidate treatment. Removal of cross-linked hemoglobin tetramers from hemolysate obtained from dimethyl adipimidate-treated cells abolished part of this effect; at pH 7.4, the solubility decreased from 20.9 +/- 1.5 to 19.4 +/- 0.2 and at pH 8.4 from 25.4 +/- 3.0 to 21.0 +/- 1.5. However, the ratio of [14C]DMA-labelled hemoglobin in the sol phase to that in the gel phase in the unfractionated hemolysate was 1.17 at pH 7.4 and 1.25 at pH 8.4, suggesting that part of the cross-linked hemoglobin tetramers was incorporated into the gel. In order to further investigate the effect of cross-linked hemoglobin tetramers on sickle hemoglobin polymerization, we separated cross-linked hemoglobin tetramers on a gel-filtration column, prepared mixtures of untreated sickle hemoglobin and cross-linked hemoglobin tetramers and studied the polymerization of these mixtures. The Csat of the untreated hemolysate increased progressively from 18.6 +/- 0.8 to 22.5 +/- 0.8 g/dl with 33% cross-linked hemoglobin tetramers. The hemoglobin concentration in the gel decreased from 43 +/- 1.0 to 33.8 +/- 1.0 g/dl with 33% cross-linked hemoglobin tetramers, while the pellet volume fraction, phi p, increased with and almost approached 1 at 50% cross-linked hemoglobin tetramers. In addition, the sol phase contained a higher molecular weight distribution of cross-linked hemoglobin tetramers than the gel phase. These observations suggest that a loose polymer was formed in the gel phase with a hemoglobin concentration much lower than that of the control. Thus, polymerization of sickle hemoglobin is inhibited by: (1) exclusion of higher molecular weight cross-linked hemoglobin tetramers from the gel, and (2) loose incorporation of cross-linked hemoglobin tetramers into the gel, perhaps preventing lateral packing and formation of tightly ordered fibers.

Chromatography, Gel↗
PubMed1984

Inadequate erythroid response to hypoxia in cystic fibrosis.

An increase in hemoglobin concentration characterizes the normal compensatory response to chronic tissue hypoxia. We observed no such increase in 42 chronically hypoxic patients with cystic fibrosis, in whom the mean concentration was 12.6 gm/dl; one third of the patients were anemic. Compared with patients with cyanotic heart disease, patients with cystic fibrosis did not have a compensatory increase in P50 or 2,3-diphosphoglycerate. Despite anemia, erythropoietin levels in patients with cystic fibrosis were not significantly different from normal control values. The growth of colony-forming units-erythroid in patients with cystic fibrosis was similar to that in control subjects, and there was no inhibition of growth with the addition of autologous serum. Erythropoietin sensitivity, determined by measuring the CFUe dose response curve, was normal in both patients and controls. Results of iron studies were consistent with iron deficiency in the majority of patients. Impaired absorption of iron was observed in six of 13 iron-deficient patients with cystic fibrosis. An inverse correlation between erythrocyte sedimentation rate and peak serum iron was obtained during the iron absorption study. Eight patients who underwent a therapeutic trial of iron demonstrated a 1.8 gm/dl rise in hemoglobin concentration. Two patients with previously documented iron malabsorption responded to parenteral iron therapy after failure to respond to oral supplementation. These studies demonstrate that patients with cystic fibrosis not only have an impaired erythroid response to hypoxia, but are frequently anemic. Their inadequate erythroid response to hypoxia results in part from disturbances in erythropoietin regulation and iron availability.

2,3-Diphosphoglycerate↗
PubMed1984

Neutrophils mediate lipid peroxidation in human red cells.

Activated neutrophils (ANs) are known to release reactive oxygen species that may cause oxidative damage to surrounding tissues. We determined if ANs could induce lipid peroxidation (LP) in human red cells and investigated the mechanism involved in this interaction. We studied neonatal glucose-6-phosphate dehydrogenase (G6PD) deficient, and sickle red cells, since each of these are known to be susceptible to oxidant injury. Neutrophils were isolated from whole blood and activated by incubation with opsonized zymosan. Mixtures of such neutrophils and red cells at a ratio of 1:100 were incubated for two hours at 37 degrees C, after which the malonyldialdehyde content in red cells was measured as an index of LP. All red cells underwent LP after AN treatment, and the degree of LP was proportional to the amount of AN in the mixture. Superoxide dismutase and catalase partially inhibited LP. When compared to normal red cells, only sickle cells demonstrated a significant increase in AN-mediated LP. Conversion of hemoglobin to carboxy-hemoglobin increased AN-mediated LP, whereas conversion to met-hemoglobin decreased AN-mediated LP. The protective effect of met-hemoglobin on LP was less in sickle cells than in normal cells. We conclude that AN can induce LP in red cells in vitro and that sickle cells are more susceptible to this process than normal cells. Hemoglobin can serve as an electron trap and protect the cell against peroxidative damage, but this mechanism is impaired in sickle cells. We speculate that the pathogenesis of hemolysis associated with infectious disease may include AN-induced red cell LP.

Cell Communication↗
PubMed1984

Evidence for a heterogeneous response to erythropoietin in the CFUE pool of human bone marrow.

To determine whether the CFUE pool within human bone marrow is heterogeneous with respect to erythropoietin (Epo) requirements, we studied CFUE growth in vitro as a function of Epo exposure time. We controlled the Epo exposure time by overlaying plasma clot cultures containing 0.5 U/ml Epo with an antibody prepared against human Epo. All cultures were grown for seven days. Benzidine-positive colonies containing eight or more cells were counted as CFUE. Colonies containing eight cells required at least 24-50 h of Epo exposure, and those containing 16 cells required at least 70-90 h of Epo exposure. After 50 h, the number of CFUE progressively increased until it reached a maximum at seven days of Epo exposure. These results suggest that the CFUE pool within human bone marrow is heterogeneous with respect to Epo requirements.

Bone Marrow Cells↗
PubMed1984

Evidence for the presence of CFU-E with increased in vitro sensitivity to erythropoietin in sickle cell anemia.

To investigate the cellular events that accompany erythroid hyperplasia, we studied several effects of erythropoietin (Epo) on marrow CFU-E in sickle cell anemia (SCA). We measured CFU-E number, CFU-E growth as a function both of Epo exposure time and of Epo concentration, and suppression of Epo-induced CFU-E formation by anti-Epo antiserum. With 0.5 U Epo/ml, the number of CFU-E was elevated in SCA (1,087 +/- 520) compared to normal (430 +/- 130). CFU-E were formed even when Epo was immediately neutralized by a 1/150 dilution of anti-Epo. After 40 hr of Epo exposure, only 2% of total CFU-E were expressed in normal marrow, whereas 12%-40% of CFU-E were expressed in SCA. Inhibition of CFU-E growth required at least 1/50 dilution of anti-Epo in SCA and a 1/300 dilution in normal marrow. In contrast to normal, a small number (5%-20%) of CFU-E were expressed in the absence of added Epo in SCA, and this pool required a 1/150 dilution of anti-Epo for inhibition. The Epo dose-response curve in SCA revealed a peak in colony formation around 0.1 U Epo/ml and 0.5 U Epo/ml, whereas only one peak at 0.5 U Epo/ml was seen in normals. These data strongly suggest that, in response to the demands of chronic erythroid hyperplasia in SCA, a pool of CFU-E is present characterized by increased in vitro sensitivity to Epo.

Anemia, Sickle Cell↗