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Biomedical subjects

M Bar-Eli

Publications and source records attributed to M Bar-Eli.

12 recordsLinked to original sources
PubMed1992

Evidence for a structurally homologous Rh-like polypeptide in Rhnull erythrocytes.

Human Rhnull red blood cells fail to react with Rh antibodies, indicating that these cells are either devoid of Rh protein or, like other species, possess antigenically distinct variants. To determine whether Rhnull cells possess an Rh-like polypeptide, 32-kDa proteins from D--, rr, and Rhnull cells were labeled with the cysteine-specific probe, 125I-labeled pyridyldithioethylamine. Size comparisons of labeled proteins in Triton X-100-solubilized membranes from Rh-bearing and Rhnull cells showed similar sedimentation coefficients and Stoke's radii. Immunoprecipitated Rh(D) from D-- cells, Rh(c) from rr cells, and purified 32-kDa proteins from Rhnull cells were digested with alpha-chymotrypsin and examined by high-performance liquid chromatography and by two-dimensional iodopeptide mapping. Analysis of 125I-labeled chymotryptic fragments from immunoprecipitated Rh(D) and Rh(c) showed the labeled peptides from both phenotypes to be virtually identical. High-performance liquid chromatography profiles and iodopeptide maps of 32-kDa Rhnull proteins yielded patterns identical to 32-kDa proteins isolated from D-- cells and rr cells with the exception of one missing 125I-labeled peptide. Further analysis of the Rh-related fragments from Rhnull cells showed significant homology with immunoprecipitated Rh(D) and Rh(c). DNA sequence analysis of cysteine-encoding regions from Rh-bearing and Rhnull cells showed complete identity. These data suggest that Rhnull red blood cells, although serologically distinct, possess an Rh-like protein that is structurally very similar to Rh(D) and Rh(c).

Amino Acid Sequence↗
PubMed1992

A crisis related analysis of perceived spectators' behavior in competition.

Spectator behavior in competition is analyzed in terms of spectators' response (positive or negative), or lack of response in reaction to a player's action, or which is independent of a player's action, in a home or away game. This study investigated the perceived contribution of these variables to extreme psychological arousal states (crisis, noncrisis). Forty-eight elite ball-game players responded to a questionnaire asking them to estimate the occurrence probability of the Bayesian combinations among these variables under crisis and noncrisis conditions. An RM-ANOVA procedure revealed that under the crisis condition a negative response, an unsuccessful action, and a home game were rated as more probable, whereas under the noncrisis condition the reverse would be true. The athlete's psychological state was more strongly related to spectator response than to game location or athlete's action. Results are discussed theoretically in reference to the crisis construct.

Arousal↗
PubMed1979

Phagocyte functions in familial Mediterranean fever.

Monocytes derived from peripheral blood of patients with familial Mediterranean fever (F.M.F.) demonstrated lower phagocytic capacity for Shigella flexneri and depressed bactericidal activity against S. albus when compared to monocytes from healthy individuals. Treatment of patients with colchicine did not alter these functions. On the other hand, chemokinesis of PMN of F.M.F. patients was enhanced especially during attacks. Colchicine treatment decreased significantly the PMN chemotactic migration.

Adolescent↗
PubMed1979

Monocyte function in psoriasis.

Monocytes derived from the peripheral blood of psoriatic patients demonstrated a significantly higher phagocytic capacity (36 to 40%) for both 125I-labeled Shigella flexneri and 125I-labeled Staphylococcus albus compared with monocytes from healthy subjects. Monocytes from psoriatic patients showed a 2-to-4fold increase in bactericidal capacity against S. albus when compared with normal monocytes. However, the bactericidal capacity of monocytes from diphylline-treated patients did not differ from that of the control subjects. The antibody-dependent cellular cytotoxicity (ADCC) activity against EL4 tumor cells was found to be similar in both psoriatic patients and control subjects. It is postulated that these abnormalities of monocyte function in psoriasis are caused by a decreased cAMP/cGMP ratio similar to the decreased cAMP/cGMP ratio found in the lesional epidermis of this disease. It seems therefore, that the psoriatic abnormality is not confined to only one type of cell, the epidermal cell.

Adult↗
PubMed1979

Neutrophil chemotaxis in psoriasis.

Neutrophil chemotaxis was assessed in 69 psoriatic patients and 37 healthy human subjects. It was found to be significantly enhanced in 52 untreated patients. In 20 patients treated with an orally-administered phosphodiesterase inhibitor, Diphylline, neutrophil chemotaxis was normal. The enhanced chemotactic response of neutrophils from untreated patients with minimal skin lesions was at least equal to the response of those from patients with extensive skin lesions. Preincubation of normal human leukocytes with plasma derived from patients with widespread lesions markedly reduced their chemotactic activity. Plasma derived from patients with extensive skin lesions exhibited marked chemoattracting properties in comparison with plasma from healthy subjects. It is postulated that the basic intrinsic abnormality of neutrophil function in psoriasis could be caused by a decreased cyclic AMP/cyclic GMP ratio, similar to the decreased cyclic AMP/cyclic GMP ratio found in the lesional epidermis of this disease. Plasma factors which influence chemotaxis in psoriasis are related to the extent of the eruption and their effect is contrary to the effect of the basic intrinsic abnormality of psoriatic neutrophils.

Administration, Oral↗
PubMed1978

Enhanced chemotactic and phagocytic activities of leukocytes in psoriasis vulgaris.

Leukocytes derived from the peripheral blood of psoriatic patients demonstrated an enhanced chemotactic response compared with leukocytes from healthy subjects. No significant difference was detected between the chemotactic response of leukocytes from patients with minimal or no skin involvement and those from patients with extensive lesions. Psoriatic leukocytes also had a significantly higher capacity to engulf 125I labeled Shigella flexneri than control leukocytes. It is postulated that a decrease in the cyclic AMP/cyclic GMP ratio in psoriatic leukocytes, similar to the imbalance of these 2 cyclic nucleotides found in the lesional epidermis of psoriasis, might be the cause of their enhanced chemotactic and phagocytic activities.

Cyclic AMP↗
PubMed1978

The mode of interaction with macrophages of two ordered synthetic polypeptides which differ in their thymus dependency.

The mode of interaction with macrophages of two ordered synthetic polypeptides (Tyr-Tyr-Glu-Glu)-poly(DLAla)--poly(Lys), (T-T-G-G)-A--L, and (Tyr-Glu-Tyr-Glu)-poly(DLAla)--poly(Lys), (T-G-T-G)-A--L, which differ in their requirements for T-B cell co-operation in the process of antibody production, was compared. The binding of the two radiolabelled antigens to the surface of peritoneal adherent cells, their uptake by the cells and the rate of their degradation were investigated. Macrophages were found to be capable of degrading both poly-peptides with the same efficiency. (T-G-T-G)-A--L, the antigen which is less T-dependent, was bound to macrophage surfaces more readily than (T-T-G-G)-A--L, the T-dependent antigen, however, its uptake by the cells was found to be lower. Thus, (T-G-T-G)-A--L remains for a longer period in the form of a membrane bound polyvalent antigen.

Animals↗
PubMed1976

Studies on the relationships between the immunogenicity and catabolism of antigens and their binding to the surface of macrophages.

The relationship between immunogenicity of Shigella paradysenteriae, the branched synthetic polypeptide poly-L (Tyr, Glu)-polylpro-polyllys [(T, G)-Pro--L] and human albumin (HSA) interacting with macrophages and kinetics of antigen degradation and degree of binding to the cell surface was studied. Following thioglycollate inoculation into C57BL/6 mice, the peritoneal-stimllated macrophages had higher levels of hydrolases as compared to unstimulated cells. The lysates of the stimulated macrophages catabolized the three labeled antigens faster than did the lysates of unstimulatec cells. However, when degradation of labeled antigens by macrophage cells was assessed, no direct correlation could be demonstrated between the level of cell hydrolases and rate of (T, G)-Pro--L or HSA catabolism. The immunogenicity of antigens following their uptake by unstimulated and stimulated macrophages was determined by transfer of the antigen-bearing cells into irradiated and nonirradiated syngeneic recipients. No correlation was apparent between the rate of antigen degradation and the capacity to evoke a humoral response. Similarly, no correlation could be demonstrated between the amount of antigen bound to the macrophage cell surface and the immunogenicity of the antigen. It is suggested that neither the rate of antigen catabolism by macrophages nor the amount of antigen bound to the macrophage membrane is the sole factor which determines the immunogenicity of antigens interacting with macrophages.

Animals↗
PubMedDate not supplied

Monocyte function in familial Mediterranean fever.

Monocytes derived from the peripheral blood of patients with familial Mediterranean fever (FMF) demonstrated a consistently lower phagocytic capacity (38-44%) for 125I-labelled Shigella flexneri when compared to monocytes from healthy subjects. Phagocytosis of both viable and killed Staphylococcus albus was similar in patients and controls. However, FMF monocytes had a two- to eight-fold depressed bactericidal capacity against S. albus in comparison to normal monocytes. Acid phosphatase and beta-glucuronidase monocyte activities were similar in patients and controls. It is suggested that the defects in monocyte function may be of importance in the pathogenesis of FMF. Colchicine had no effect on any of the indices studied.

Adolescent↗