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Biomedical subjects

B Lubin

Publications and source records attributed to B Lubin.

At least 91 records · Page 5Linked to original sources
PubMed1988

Affects, demographic variables, and health.

The revised Multiple Affect Adjective Check List (MAACL-R) was given to a national probability sample that consisted of 1,543 adults who also were interviewed, which provided demographic data and self-ratings of health, medication use, and social activities. Standardization procedures have reduced markedly the acquiescence factor and the correlations among the dysphoric affect scales in the MAACL-R. The demographic variables of sex, race, age, education, occupation, income, marital status, religion, geographical area of residence, and size of town or city were related to some of the scales. Positive affect was related directly to self-ratings of health; dysphoric affect was related negatively to these ratings. Frequencies of volunteer activities and social activities in general correlated negatively with depression and positively with positive affect scales.

Adult↗
PubMed1988

The Children's Depression Adjective Check lists (C-DACL) with emotionally disturbed adolescent boys.

In this study of the reliability and validity of the Children's Depression Adjective Check Lists (C-DACL; Brewer & Lubin, 1987) with emotionally disturbed adolescent boys (N = 50), data were collected on two occasions. Internal consistency (alpha) was .89 and .94 for form H and .89 and .95 for form I. Alternate form reliabilities were .86 and .95. Split-half reliabilities were .80 and .89 for form H and .68 and .86 for form I. Concurrent validity was determined by correlations between C-DACL and the Self-Rating Scale of Depressed Mood. Correlations were .65 and .80 for H and .54 and .80 for I. Data from the present study were tested against data from emotionally disturbed adolescent girls (Sokoloff & Lubin, 1983), with boys scoring significantly lower on both forms (H and I) of the C-DACL.

Adolescent↗
PubMed1988

Human erythrocyte protein 4.1 is a phosphatidylserine binding protein.

The aminophospholipids phosphatidylethanolamine (PE) and phosphatidylserine (PS) are the major phospholipids contained in the cytoplasmic leaflet of the human erythrocyte (RBC) plasma membrane and are largely confined to that leaflet over the entire RBC lifespan. In particular, PS, which comprises approximately 13% of total RBC membrane phospholipids, is normally restricted entirely to the cytoplasmic leaflet. However, molecular mechanisms that regulate this asymmetric distribution of phospholipids are largely unknown. We examined elliptocytic RBCs that completely lacked protein 4.1 (HE [4.1 degrees]), but contained normal amounts of all other peripheral membrane proteins, and found approximately 10% of total membrane PS was accessible in the exoplasmic leaflet of these membranes. Inside out vesicles (IOVs) derived from HE [4.1 degrees] RBCs bound fewer PS liposomes than did IOVs derived from normal RBCs. Normal IOVs that were depleted of proteins 2.1 (ankyrin), 4.1, and 4.2 bound fewer PS liposomes similar to HE [4.1 degrees] IOVs, and repletion with protein 4.1 restored PS liposome binding to control levels. Addition of purified protein 4.1 to PS liposomes resulted in saturable binding with the extent of binding being proportional to the liposome PS content. Our data suggests that human RBC protein 4.1 is a PS binding protein and may be involved in the molecular mechanisms that stabilize PS in the cytoplasmic leaflet of the human RBC plasma membrane.

Blood Proteins↗
PubMed1988

Deficiency of protein 4.2 in erythrocytes from a patient with a Coombs negative hemolytic anemia. Evidence for a role of protein 4.2 in stabilizing ankyrin on the membrane.

A patient with a mild hemolytic anemia and osmotically fragile, spherocytic erythrocytes was studied. Analysis of the erythrocyte membrane proteins by SDS-PAGE revealed a deficiency of protein 4.2 (less than 0.10% of normal). The protein 4.2-deficient erythrocytes contained normal amounts of all other membrane proteins, although the amount of band 3 was slightly reduced and the amount of band 6 (G3PD) was slightly elevated. The spectrin content of these cells was normal, as measured by both SDS-PAGE and radioimmunoassay. Erythrocytes from the patient's biologic parents were hematologically normal and contained normal amounts of protein 4.2. Immunological analysis using affinity purified antibodies revealed that the patient's protein 4.2 was composed of equal amounts of a 74-kD and 72-kD protein doublet, whereas the normal protein was composed primarily of a 72-kD monomer. Proteolytic digestion studies using trypsin, alpha-chymotrypsin and papain demonstrated that the patient's protein 4.2 was similar but not identical to the normal protein. Binding studies showed that the protein 4.2-deficient membranes bound purified protein 4.2 to the same extent as normal membranes, suggesting that the membrane binding site(s) for the protein were normal. Depleting the protein 4.2-deficient membranes of spectrin and actin resulted in a loss of nearly two-thirds of the membrane ankyrin, whereas similar depletion of normal membranes resulted in no loss of ankyrin. Repletion of the protein 4.2-deficient membranes with purified protein 4.2 before spectrin-actin extraction partially prevented the loss of ankyrin. These results suggest that protein 4.2 may function to stabilize ankyrin on the erythrocyte membrane.

Adult↗
PubMed1988

Diet-induced asymmetry of the phosphatidylcholine fatty acyl composition in rat erythrocyte membranes.

The effect of dietary fat on the distribution of fatty acids within the bilayer of red cell membrane phosphatidylcholine was determined after feeding young female rats semipurified diets containing 10% of either hydrogenated cottonseed oil, menhaden oil, or corn oil for 4 days. Changes in fatty acyl composition of both plasma and erythrocyte phosphatidylcholine were noted. The composition of the fatty acids in phosphatidylcholine in the outer leaflet of the bilayer was determined after hydrolysis of outer leaflet phospholipids, first with phospholipase A2 and subsequently with sphingomyelinase. The distributions of acyl constituents of phosphatidylcholine in the inner and the outer monolayers of the membrane were found to be distinctively different, regardless of the dietary fat intake. For example, palmitic acid and oleic acid were predominantly present in the phosphatidylcholine of the inner monolayer, and arachidonic acid and docosahexaenoic acid were present in that of the outer monolayer. Despite such diet-induced changes in phosphatidylcholine fatty acid composition, no alteration in erythrocyte integrity was observed when monitored by either morphology or ektacytometry.

Animals↗
PubMed1988

Newborn screening for sickle cell disease: effect on mortality.

Newborn screening for sickle cell disease has been recommended as a method of decreasing patient mortality. However, its effectiveness in accomplishing this has not been reliably measured. To help determine the effectiveness, 10 years of experience in newborn screening have been summarized. The effects of early patient enrollment in a comprehensive treatment program on long-term morbidity and mortality are reported. From 1975 to 1985, 84,663 newborns were screened regardless of race or ethnic background. Bart's hemoglobin was present in 5%, hemoglobin AS in 2.6%, and hemoglobin AC in 0.75%. Excluding Bart's, approximately 3.6% of all newborns were carriers for hemoglobinopathy. Sickle cell disease occurred in 1:951 births (58 hemoglobin SS, 25 hemoglobin FSC, three hemoglobin S-beta +-thalassemia, and three hemoglobin S-beta O-thalassemia). In addition, one in every 4,233 newborns had a clinically significant thalassemia syndrome (eight hemoglobin FE, ten hemoglobin F only, two hemoglobin H). Compared with other newborn screening programs in California, (congenital hypothyroidism, 1:3,849; phenylketonuria 1:22,474, galactosemia 1:74,103), hemoglobinopathies are the most prevalent congenital disease. Eighty-one newborns with sickle cell disease were followed for 7.2 years. Patients experienced 513 hospitalizations, including 13 episodes of sepsis with or without meningitis and ten acute sequestration crises. The overall mortality rate for patients with sickle cell anemia diagnosed in the newborn period was 1.8%. In comparison, the clinical course of 64 patients with sickle cell anemia diagnosed after 3 months of age and followed for an average of 9.4 years was analyzed. Five of these patients died. In two of these, sickle cell anemia was diagnosed at the time of the death.(ABSTRACT TRUNCATED AT 250 WORDS)

Anemia, Sickle Cell↗
PubMed1987

Altered plasma membrane phospholipid organization in Plasmodium falciparum-infected human erythrocytes.

The intraerythrocytic development of the malaria parasite is accompanied by distinct morphological and biochemical changes in the host cell membrane, yet little is known about development-related alterations in the transbilayer organization of membrane phospholipids in parasitized cells. This question was examined in human red cells infected with Plasmodium falciparum. Normal red cells were infected with strain FCR3 or with clonal derivatives that either produce (K+) or do not produce (K-) knobby protuberances on the infected red cells. Parasitized cells were harvested at various stages of parasite development, and the bilayer orientation of red cell membrane phospholipids was determined chemically using 2,4,6-trinitrobenzene sulphonic acid (TNBS) or enzymatically using bee venom phospholipase A2 (PLA2) and sphingomyelinase C (SMC). We found that parasite development was accompanied by distinct alterations in the red cell membrane transbilayer distribution of phosphatidylcholine (PC), phosphatidylethanolamine (PE), and phosphatidylserine (PS). Increases in the exoplasmic membrane leaflet exposure of PE and PS were larger in the late-stage parasitized cells than in the early-stage parasitized cells. Similar results were obtained for PE membrane distribution using either chemical (TNBS) or enzymatic (PLA2 plus SMC) methods, although changes in PS distribution were observed only with TNBS. Uninfected cohort cells derived from mixed populations of infected and uninfected cells exhibited normal patterns of membrane phospholipid organization. The observed alterations in P falciparum-infected red cell membrane phospholipid distribution, which is independent of the presence or absence of knobby protuberances, might be associated with the drastic changes in cell membrane permeability and susceptibility to early hemolysis observed in the late stages of parasite development.

Erythrocyte Membrane↗
PubMed1987

The molecular species composition of phosphatidylcholine affects cellular properties in normal and sickle erythrocytes.

The phosphatidylcholine specific transfer protein (PCTP) from bovine liver was used to retailor the molecular species composition of phosphatidylcholine (PC) in the membrane of normal (AA) and sickleable (SS) human erythrocytes. Changes in molecular species composition of PC altered morphology as well as cellular deformability and stability as measured with ektacytometry. In normal cells, replacement of native PC with 1-palmitoyl,2-arachidonoyl PC (PAPC) resulted in a decrease in osmotic fragility with no change in hydration, whereas replacement with 1,2-dipalmitoyl PC (DPPC) led to an increased osmotic fragility and cellular hydration. Replacement of native PC by 1-palmitoyl,2-oleoyl PC (POPC) in normal cells had no apparent effect on these parameters. In contrast, replacement of native PC in sickle cells with either PAPC, DPPC or POPC led to cellular hydration. Facilitation of PC exchange between subpopulations of SS cells separated on buoyant density also led to cellular hydration. These observations suggest that the state of hydration of sickle cells can be modified by the fatty acyl composition of PC and illustrate a a role for the lipid core in the observed permeability changes in sickle erythrocytes. They also raise the interesting possibility that the state of cellular hydration of sickle cells may be modulated by altering the molecular species composition of the membrane phospholipids.

Anemia, Sickle Cell↗
PubMed1987

Neutrophil-induced K+ leak in human red cells: a potential mechanism for infection-mediated hemolysis.

Activated neutrophils (AN) when incubated with red blood cells (RBCs) at a ratio of 1:100 were shown to damage RBCs as reflected by an increase in passive potassium (K+) permeability. Oxygenated sickle cells were more susceptible to this injury than normal (AA) RBCs. In both normal and sickle cells, the degree of K+ leak was found to be linearly related to the amount of AN in the incubation mixture. Pretreatment of AA RBCs with low-dose H2O2 resulted in an increased K+ leak after exposure to AN. Compared with patients with stable sickle cell anemia, those who were observed while infected or in crisis had notably more K+ leak from their RBCs after AN exposure. Addition of activated neutrophils from a patient with chronic granulomatous disease resulted in K+ leak from normal RBCs, despite a deficiency in production of toxic oxygen species. Cell-free supernatants from AN also mediated K+ leak. Sickle cells were, again, leakier after exposure to these preparations. Scavengers of toxic oxygen species inhibited up to 40% of the leak, whereas the maximal inhibition obtained by using protease inhibitors was 60%. Addition of autologous plasma in low concentrations inhibited the leak but also resulted in hemolysis, probably via a different mechanism. These studies demonstrate that measurement of passive K+ loss from RBCs allows discrimination between two separate mechanisms of AN-induced damage, an oxidant mechanism, as has been previously described, and a new pathway that appears to be mediated by granule-associated enzymes released from AN. The increased susceptibility of sickle RBCs, especially during periods of increased physiologic stress, suggests that previous membrane damage in vivo may render these RBCs more sensitive to the action of either oxidants or granules released from neutrophils.

Anemia, Sickle Cell↗
PubMed1986

Effect of sickling on dimyristoylphosphatidylcholine-induced vesiculation in sickle red blood cells.

To study the effect of sickling on dimyristoylphosphatidylcholine (DMPC)-induced vesiculation, sickle (SS) red blood cells were incubated with sonicated suspensions of DMPC under either room air or nitrogen. Like normal red cells, when sickle cells were incubated with DMPC under oxygenated conditions, incorporation of DMPC into the erythrocyte membrane occurred, followed by echinocytic shape transformation and subsequent release of membrane vesicles. On the other hand, when SS cells were induced to sickle by deoxygenation, DMPC-induced vesiculation of these cells was dramatically reduced. However, upon reoxygenation, release of vesicles from these sickle erythrocytes occurred immediately. When SS cells were incubated under hypertonic (500 mosM) and deoxygenated conditions (where hemoglobin polymerization occurs but red cells do not show the typical sickle morphology), a similar decrease in the extent of vesiculation was observed. Experiments with radiolabelled lipid vesicles indicated that incorporation of DMPC into erythrocyte membranes occurred in all cases and therefore was not the limiting factor in the reduction of vesiculation in deoxygenated SS cells. Taken together, these results indicate that cellular viscosity and membrane rigidity, both of which are influenced by hemoglobin polymerization, are two important factors in process of vesicle release from sickle erythrocytes.

Anemia, Sickle Cell↗
PubMed1986

College student mental health: a person-environment interactional analysis.

The interactional effects of person characteristics (stimulus screening tendency, self-disclosure tendency, locus of control, and integration of self with other students and the college) and environmental factors (life events) on psychological distress were studied in the comparison of a group of college students who sought help (N = 70) from a student counseling service with a group that did not seek help (N = 70). The results confirmed the importance of social support on the psychological effects of stress. Stimulus screening and locus of control also were related to psychological strain. The pattern of the relationships depended upon whether mood disturbance or help seeking behavior was targeted.

Adult↗
PubMed1986

Training in geropsychology at the doctoral level: 1984.

To study type and amount of training in geropsychology available to students in APA-approved doctoral programs in clinical and counseling psychology, a questionnaire was mailed to all such programs in 1984. Response rate was 71 of 132 (59%) for clinical programs and 27 of 37 (73%) for counseling programs. Very little difference was found between responses of clinical and counseling programs and between this 1984 survey and one conducted in 1975-76. There seems to be a very small increase in training opportunities for psychology students in geropsychology in 1984 at the doctoral level.

Education, Graduate↗
PubMed1986

The aging process of human neonatal erythrocytes.

The red blood cell population of the human newborn is more heterogeneous than that of adults. To characterize this heterogeneity, red cells were separated on Stractan gradients into populations according to their density and, therefore, generally according to their age. Lipid content, phospholipid asymmetry, osmotic fragility, and deformability were measured. With increasing density, osmotic resistance and deformability decreased to a greater extent in the neonatal than the adult red cell. There was a marked loss of surface area throughout the life span of the neonatal red cell which was not accompanied by a parallel loss of membrane lipid. This apparent discrepancy could be explained at least in part by internalization of membrane lipid as a result of endocytosis, a process shown to be present in even the densest neonatal red cells.

Adult↗
PubMed1986

The new MAACL scales with adolescents: preliminary reliability and validity determinations.

This study reports on the reliability and concurrent validity of both the trait and state forms of the Multiple Affect Adjective Check List (MAACL) with a high school population, age range of 14-16 years and educational range of 9th and 10th grades (N = 403). Alphas of the four scales (anxiety, depression, hostility, and positive affect) ranged from .67 to .91. Correlations with a check-list of stress-related symptoms and an inventory of the number of extracurricular activities in which the students participated were significant and in the expected direction. Means and standard deviations on the MAACL scales were similar to those of college students. Sex differences were found on some of the scales. The findings indicate that the MAACL is sufficiently reliable and valid to warrant additional use with an adolescent population.

Adolescent↗
PubMed1985

Abnormal transbilayer mobility of phosphatidylcholine in hereditary pyropoikilocytosis reflects the increased heat sensitivity of the membrane skeleton.

We determined whether the membrane defect in hereditary pyropoikilocytosis (HPP) is associated with thermally induced changes in the lipid bilayer, the stability of which was probed by the rate of translocation of phosphatidylcholine (PC) over the two leaflets. [14C]PC was incorporated into the outer leaflet of the lipid bilayer of the intact erythrocytes using a PC-specific phospholipid exchange protein. The transbilayer equilibration of this PC was determined by measuring the time-dependent changes in its accessibility to exogenous phospholipase A2. The rate of transbilayer equilibration of PC was increased in HPP cells at 37 degrees C when compared to normal erythrocytes (rate constants, 0.07 +/- 0.02 and 0.03 +/- 0.01 h-1, respectively). A further dramatic increase in PC transbilayer equilibration was noted in HPP cells incubated at 44 degrees C (rate constant, 0.15 +/- 0.02 h-1). A similar marked acceleration in transbilayer movement of PC was also seen in normal erythrocytes when incubated at 46 degrees C (rate constant, 0.13 +/- 0.03 h-1). Despite the enhanced transbilayer mobility of PC in HPP cells when compared to normal erythrocytes, no major alteration in the asymmetric distribution could be observed when probed with phospholipase A2. Since changes in transbilayer mobility of PC and cell morphology occur in HPP cells at lower temperature than in normal red cells, it may be concluded that the enhanced thermal sensitivity of spectrin is the major factor responsible for these changes. Our results therefore support the view that the structural integrity of the skeletal network is essential for stabilization of the lipid bilayer of the red cell membrane.

Anemia, Hemolytic, Congenital↗