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Biomedical subjects

A Etzioni

Publications and source records attributed to A Etzioni.

At least 19 recordsLinked to original sources
PubMed1995

Leukocyte adhesion deficiency (LAD) II.

The occurrence of recurrent bacterial infections, neutrophil motility dysfunction and normal expression of beta 2 integrins (CD18) in two unrelated children suggested an as yet undescribed adhesion deficiency. The fact that both children exhibited the rare Bombay blood group and were Lewis negative, each involving carbohydrates with different fucose linkages, suggested a possible defect in the fucose-containing ligand for E- and P-selectin, sialyl Lewis X (SLe(x)). Using a monoclonal anti-SLe(x) antibody, we did not detect expression of SLe(x) on the neutrophils of the patients. Adhesion of neutrophils to endothelial cells activated with interleukin-1 beta or histamine was markedly decreased ( < 5% of control). The observation that the neutrophils did not bind to recombinant E-selectin and purified P-selectin confirmed the SLe(x) deficiency as the basis for adhesion deficiency. Using several in vivo techniques, we were able to show that neutrophil rolling, the first step in their adhesion, is markedly decreased, and therefore neutrophil emigration through the endothelium and arrival at site of inflammation is significantly diminished (1-2% of normal). Low binding of fucose-specific lectins to the patients' B lymphocytes transformed with Epstein-Barr virus was observed, while the binding of mannose-specific lectins was normal, providing further evidence for a general fucose deficiency as the primary defect. The existence of the patients and their deficiency emphasizes the essential role of the endothelial cell selectins and their ligand, SLe(x), in recruitment of neutrophils to sites of infection.

Cell Adhesion↗
PubMed1995

A Bombay individual lacking H and Le antigens but expressing normal levels of alpha-2- and alpha-4-fucosyltransferases.

BACKGROUND: The rare Bombay phenotype is usually due to a primary genetic defect in an alpha-2- or alpha-4-fucosyltransferase. The present study was done to investigate a patient with normal transferases, who exhibits the Bombay phenotype. CASE REPORT: Red cells of the patient, his parents, and siblings were phenotyped for A, B, and H antigens. The presence of B, H, and Le transferases in serum and saliva was measured. RESULTS: The parents and siblings were all group B, Le(a-b-). The propositus was typed as Oh, Le(a-b-). His serum contained anti-A, anti-B, and anti-H. Normal levels of B, H, and Le transferases were found in all family members including the patient. CONCLUSION: In an unusual case, a person has the Bombay phenotype, but normal levels of transferases in serum and saliva. A general defect in fucose metabolism seems to be the primary abnormality in this case.

ABO Blood-Group System↗
PubMed1995

In vivo destruction of melanocytes by the IgG fraction of serum from patients with vitiligo.

There are conflicting results regarding the role of autoantibodies in the pathogenesis of vitiligo. To examine their in vivo effect, human skin was transplanted onto nude mice injected with purified IgG obtained from patients with vitiligo and from controls. The effect was evaluated by several techniques. Dihydroxyphenylalanine staining revealed a marked decrease in the number of melanocytes in skin grafted onto mice injected with patients' IgG. Direct immunofluorescence staining demonstrated the presence of human IgG throughout the epidermis in specimens injected with purified IgG from vitiligo patients. No staining was observed when control IgG was injected. Electron microscopy studies demonstrated a marked decrease in melanin pigmentation with only rare melanosomes and melanocytes detected in grafts injected with patients' IgG. Thus all three techniques showed the destructive effect of vitiligo patients' serum on melanocytes. Our study highlights the important role of autoantibodies in the pathogenesis of vitiligo.

Animals↗
PubMed1992

Rambam-Hasharon syndrome of psychomotor retardation, short stature, defective neutrophil motility, and Bombay phenotype.

We describe 2 Arab patients, both offspring of unrelated consanguineous matings, with unusual facial appearance, severe mental retardation, microcephaly, cortical atrophy, seizures, hypotonia, dwarfism, and recurrent infections with neutrophilia. Neutrophil motility was markedly decreased but the opsonophagocytic activity was normal. Both patients lack the red blood cell (RBC) H antigen and manifest the Bombay (hh) phenotype. Familial endocardial fibroelastosis and familial tetralogy of Fallot segregated independently in one family. The occurrence of the same syndrome in 2 unrelated families suggests that the various aspects of the disorder are the pleiotropic effects of a single mutation. Homozygosity-by-descent for a deletion involving contiguous genes may explain the findings in this syndrome. Alternatively, a mutation which involves an ubiquitous GDP fucose donor rather than the enzyme (alpha 2-L-fucosyltransferase) or its substrate (glcNAc) may account for the pleiotropic manifestations in this syndrome.

ABO Blood-Group System↗
PubMed1992

Ia expression in keratinocytes following ultraviolet radiation.

Injections of murine gamma interferon (IFN-gamma) into BALB/c nude mice induced Ia expression by keratinocytes. The aim of the present study was to use this murine model to determine the effect of ultraviolet radiation (UV) or cyclosporine A (CyA) on Ia expression by keratinocytes. Two sets of experiments were performed. In the first, mice were injected intraperitoneally with IFN-gamma for 6 days. The mice were divided into three groups. One group, with one ear protected by electrical tape, was exposed to UVB radiation for 15 days starting 4 days before the injection. The second group received subcutaneous injections of CyA simultaneously with the IFN-gamma and during the 10 days following the IFN-gamma injection. The third group received only IFN-gamma injections. Fifteen days after the IFN-gamma injection all mice were killed and evaluations of Ia positive cells were performed. In the second set of experiments the nude mice were treated with CyA or UVB only 10 days after the last IFN-gamma injections. In both experiments UVB inhibited and down-regulated Ia expression by keratinocytes. This effect on keratinocytes was not observed in the protected ears. Thus it appears that the effect of UVB on keratinocytes is local and not systemic. CyA failed to inhibit or down-regulate Ia expression. This study may shed some light on understanding the mechanism effect of UV radiation in a variety of skin diseases.

Animals↗
PubMed1991

High dose intravenous gamma-globulin in intractable epilepsy of childhood.

Eight children aged between 1.3 and 13 years suffering from epilepsy refractory to conventional anticonvulsive therapy were treated with high dose intravenous gamma globulin (200 mg/kg, 3 times per week, repeated after 3 weeks). Immunological studies after therapy showed normal results. In four children, clinical and EEG findings markedly improved. In one other case a partial response was noted. No improvement was observed in the remaining three cases. We confirm that although the mechanism is still obscure, high doses of i.v. gammaglobulin may have a beneficial effect in a significant number of children with intractable epilepsy.

Adolescent↗
PubMed1991

Effect of cyclosporine A on the regulation of Ia antigen keratinocytes expression.

Since many skin diseases characterized by positive Ia keratinocytes show improvement with cyclosporine therapy, the purpose of this study was to determine whether cyclosporine A (CyA) alters the expression of Ia keratinocytes. Nude mice were injected with normal mouse serum (NMS) to induce keratinocyte expression of the Ia antigen. The injected mice were then divided into four groups: one was treated with oral CyA; the second was treated topically with CyA twice a day; the third was treated topically with olive oil; and the fourth was injected with nude mouse serum. The third and fourth groups served as Ia positive and Ia negative controls, respectively. The mice were treated during the first 10 days after the injections. On Day 10, epidermal sheets were analyzed for Ia expression. Analysis was made by an indirect immunoperoxidase staining method using monoclonal antibodies specific for Ia determinants. Quantitation of the number of Langerhans cells was analyzed on epidermal sheets using immunodiagnostic reagents, anti-MHC-Ia, and surface ectoenzyme, ATPase. A significant reduction of Ia-positive keratinocytes was noted in the oral CyA group vs topical and olive oil groups (64.9 +/- 29.9% vs 20.1 +/- 18.7%, respectively, P less than 0.01). In a second set of experiments mice were injected with NMS, but treatment was started only on Day 10 after injections, for 10 days. The results showed that CyA failed to down-regulate Ia expression. Topical and systemic CyA did not modify Langerhans cell population. The present study showed that systemic administration of CyA significantly reduced Ia induction by keratinocytes of nude mice that were injected with NMS.

Animals↗
PubMed1991

Topical cyclosporin induces hair growth in human split skin grafted onto nude mice.

Previously we observed that systemic CyA induces hair growth in an experimental model of human scalp skin graft transplanted onto nude mice. In the present study we investigated the role of topical CyA in the murine transplantation model, using human split-thickness skin grafts (HSTSG). Ten mice grafted with 1-mm-thick skin and another 10 mice grafted with 0.4-mm-thick skin were treated topically with CyA in olive oil. Ten other mice, treated with olive oil only, served as a control group. At the end of the study we observed hair growth only on the grafted skin of the CyA-treated group. Four out of 10 grafts showed hair growth in each of the groups. Quantitative analysis of transverse sections of cylindrical punch biopsy specimens of HSTSG before transplantation revealed anagen follicles, including small ones and telogen/catagen follicles, whereas specimens after skin transplantation showed terminal follicles mostly in the anagen phase. The present study provides further support to previous observations regarding the beneficial effect of CyA on hair growth.

Administration, Topical↗
PubMed1991

Effect of urine and urine components on the chemiluminescent response of bacteria-stimulated polymorphonuclear leukocytes.

The role of polymorphonuclear leukocytes (PMN) found in urine during infectious episodes is still unknown. Opsonophagocytosis of Escherichia coli by normal blood PMN in the presence of urine was measured using a chemiluminescence (CL) assay. PMN were challenged by a type I fimbriated E. coli strain shown to elicit a CL response through attachment to the mannose-containing receptors on the leukocytes. In the presence of urine the CL response decreased significantly. Urine osmolality due to inorganic salts partially caused this decrease. A higher inhibitory effect was elicited by urea. Under otherwise similar conditions, the presence of an additional CL-inhibiting factor, most probably a protein, was detected in urine; however, its identity has not yet been defined. In vitro and in vivo urine dilution improved PMN function. No difference in effect on CL response was found between urine obtained from 25 children with recurrent urinary tract infections and urine from 15 age-matched controls.

Adolescent↗
PubMed1990

Topical cyclosporine in male pattern alopecia.

We previously demonstrated a systemic and topical effect of cyclosporine on hair growth in an experimental model composed of human scalp skin transplanted onto nude mice. The aim of this study was to determine whether topical cyclosporine affects male pattern alopecia. For 4 months in a double-blind study, 10 subjects were treated with cyclosporine and three were treated with olive oil. Hair growth was evaluated by photographs and hair counts. Significant hair growth was observed in two of the eight patients who completed the study. In one the hair growth was cosmetically satisfactory. No systemic or cutaneous side effects were noted.

Administration, Topical↗