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Biomedical subjects

E Levi

Publications and source records attributed to E Levi.

At least 73 records · Page 4Linked to original sources
PubMed1987

Mechanism of action of cysteamine on duodenal alkaline phosphatase.

A single s.c. injection of cysteamine-HCl, a potent duodenal ulcerogen, drastically decreased duodenal alkaline phosphatase (DAP) activity in mucosal cells. The effect was detectable 4 hr after the injection of cysteamine, it was the most prominent at 12 hr and lasted less than 24 hr after the ulcerogen administration. Under the same experimental conditions cysteamine did not affect alkaline phosphatase activity in the liver. Furthermore, ethanolamine, the toxic but nonulcerogenic derivate of cysteamine, had no effect on the DAP activity if given in equimolar quantities. Thus, the effect of DAP activity seems to be a property of the duodenal ulcerogen, related only to the target organ, i.e. duodenal mucosa. Since cimetidine administration and pylorus ligation, which both abolish HCl hypersecretion provoked by cysteamine, did not "protect" the enzyme from the depletion, it is hard to believe that gastric acid hypersecretion could be responsible for the enzyme depletion provoked by the ulcerogen. Dopamine metabolism disorders, induced by cysteamine administration in the brain and duodenal mucosa, are not causally related to DAP-depletion either. Cysteamine most probably inhibits the DAP activity by three different mechanisms, by one acting directly on the enzyme molecules and by two others acting indirectly, through its adrenocorticolytic and stresogenic effects.

Adrenalectomy↗
PubMed1987

Purification and biochemical characterization of a human autocrine growth factor produced by Epstein-Barr virus-transformed B cells.

Autocrine growth factor for Epstein-Barr virus-transformed human B cells (aBGF), a protein that is constitutively produced by the human EBV-transformed B cell line 5/2, has been purified from serum-free conditioned medium. The purification involved sequential ammonium sulfate precipitation, ion exchange chromatography, gel filtration, and reversed-phase high performance liquid chromatography. The purified protein has a m.w. of 16,000 in NaDodSO4/polyacrylamide gel electrophoresis and an isoelectric point between 7.0 and 8.0. The relative molecular mass 16,000 form exists in equilibrium with dimeric and tetrameric forms. aBGF supports the growth of EBV-transformed B cells, which have been deprived of their own conditioned medium. The purified aBGF is fully effective at 0.5 ng/ml and has no interleukin 1 activity in the lymphocyte activation factor assay. Because several randomly selected lines of EBV-transformed cells and one EBV-negative lymphoma cell line both produce aBGF activity and show growth dependency on aBGF and because stimulation of normal B cells with anti-immunoglobulin M is increased by aBGF, we propose that aBGF has general significance for growth control of human B cells.

B-Lymphocytes↗
PubMed1987

Bradycardia during elevation of a zygomatic arch fracture.

A case of bradycardia occurring during elevation of a zygomatic arch fracture is reported and possible mechanisms for the phenomenon are discussed. This case report serves to alert oral and maxillofacial surgeons and anesthesiologists to a possible hazard during surgical elevation of a fractured zygomatic arch.

Adult↗
PubMed1986

Pluripoietin alpha: a second human hematopoietic colony-stimulating factor produced by the human bladder carcinoma cell line 5637.

We have identified a factor constitutively produced by the human bladder carcinoma cell line 5637, which has the following capacities: to induce the differentiation of the human promyelocytic leukemic cell line HL-60; to induce the expression of chemotactic peptide receptors in leukemic cells as well as in normal peripheral blood granulocytes; to function as a chemoattractant for neutrophils as well as, under certain conditions, inhibiting their migration; to support the growth of eosinophil and granulocyte/macrophage progenitors, which is maximal when scored at day 14; and to support the growth of human mixed pluripotent progenitors and erythroid bursts from normal human bone marrow. This factor has a molecular size of 32 kDa by gel filtration and 16.5 kDa by NaDodSO4/PAGE. We have termed this factor pluripoietin alpha.

Bone Marrow Cells↗
PubMed1985

Purification and biochemical characterization of human pluripotent hematopoietic colony-stimulating factor.

Pluripotent hematopoietic colony-stimulating factor (pluripotent CSF), a protein that is constitutively produced by the human bladder carcinoma cell line 5637, has been purified from low serum (0.2% fetal calf serum)-containing conditioned medium. The purification involved sequential ammonium sulfate precipitation, ion-exchange chromatography, gel filtration, and reversed-phase high-performance liquid chromatography. The purified protein has a molecular weight of 18,000 in NaDodSO4/polyacrylamide gel electrophoresis, both by the silver staining technique and by elution of biological activity from a corresponding gel slice, and has an isoelectric point of 5.5. Pluripotent CSF supports the growth of human mixed colonies, granulocyte-macrophage colonies, and early erythroid colonies and induces differentiation of the human promyelocytic leukemic cell line HL-60 and the murine myelomonocytic leukemic cell line WEHI-3B (D+). The specific activity of the purified pluripotent CSF in the granulocyte-macrophage colony assay is 1.5 X 10(8) units/mg of protein.

Biological Assay↗
PubMed1985

Plasma exchange-induced biological stress of the Hagemann-mediated systems: results of contact activation and plasma substitution.

Plasma exchange can induce changes in the biological systems of coagulation, fibrinolysis, complement and kinins, either by contact activation or plasma substitution. In order to know which of the two is responsible, the actual initial and final values and theoretical calculated final values were compared. Fibrinogen, Antithrombin III and platelets fell more than expected, and there was a significant increase in Platelet-Factor four and Betathromboglobulin which was greater than would produced by plasma substitution alone. Fibrinolysis is shortened and white cells rise. Complement and kinins were not significantly changed. During plasma exchange, contact activation actually triggers coagulo-fibrinolytic pathway and stresses cellular components.

Adult↗
PubMed1984

Characterization of low-molecular-weight acid phosphoprotein phosphatase associated with rat splenic cell nucleoli.

Evidence is presented on the existence of an acid phosphoprotein phosphatase (APPase) associated with rat splenic cell nucleoli. The enzyme is purified 1250-fold from 0.3 M NaCl nucleolar extract by means of chromatography on P cellulose and Sephacryl S-200. The nucleolar acid phosphoprotein phosphatase is a very basic protein (pI 8.3) and shows maximal activity at pH 5.8. It dephosphorylates acidic phosphoproteins (casein and phosvitin), ATP, and p-nitrophenyl phosphate, but not basic phosphoproteins (histones and protamine phosphate). The enzyme activity is very dependent on reducing agents, especially on ascorbic acid. Divalent and monovalent cations did not affect phosphatase activity, but heavier divalent metals, Co2+ and Zn2+, strongly inhibit the enzyme activity. The activity was also inhibited by N-ethylmaleimide, indicating a requirement for free sulfhydryl groups. The estimated molecular weight of the purified enzyme is approximately 38,000 by gel filtration and sedimentation in sucrose gradient concentration.

Animals↗
PubMed1984

Human B cell-inducing factor(s) for production of IgM, IgG and IgA: independence from IL 2.

Human peripheral blood B cells are stimulated into proliferation by killed Staphylococcus aureus bacteria strain Cowan I (Sac). T lymphocytes in the presence of a T cell mitogen induce high numbers of immunoglobulin-secreting cells (ISC) in these Sac-stimulated B cells. The T cells can be largely replaced by a lymphokine factor. We describe here the 11000-fold purification of this B cell-inducing factor (BIF). BIF preparations that are free of IL 2 do not require IL 2 for optimal induction of ISC. This was shown by the lack of effect of IL 2 alone or with suboptimal or optimal concentrations of BIF on the induction of ISC and by the absence of IL 2 production in the purified B cell population which, with other controls, excludes significant T cell contamination. BIF, purified through four fractionation steps and free of IL 2, induces IgM, IgG, and IgA-ISC in approximately the same ratio as unfractionated lymphokine. Because we have not yet attained a pure BIF preparation, the possibility of separate factors for the production of each immunoglobulin isotype cannot be ruled out.

Adult↗
PubMed1983

Activation of the coagulation system and leukocytes kinetics in plasma exchange.

The activation of the coagulation system--commonly occurring in other extracorporeal circulation--is still debated, in plasma exchange (PE), data being conflicting due to the different types of replacement fluid used in 25 patients treated by PE using a discontinuous plasma separator (14 with freshly-frozen plasma, 8 with half plasma half 5% albumin, 3 with only 5% albumin). The occurrence of leukocytes stress is proved by their marked increase at the end of the procedure while the platelet fall is superimposable to the HTC fall. A coagulation-fibrinolytic activation seems to be demonstrated by plasma increase in endoplatelet constituents, fibrinogen and antithrombin III consumption, and shortening in fibrinolytic tests, but caution must be made in interpreting these results because the donor's plasma units show high levels of platelet endogranular constituents and a wide variable range of coagulation-related proteins, which can interfere with an appropriate evaluation of the results.

Blood Coagulation↗
PubMed1981

Infantile flexural seborrhoeic dermatitis. Neither biotin nor essential fatty acid deficiency.

The allegedly beneficial effect of biotin in the treatment of infantile 'flexural' seborrhoeic dermatitis was evaluated in a double-blind controlled study. No beneficial effect could be confirmed, and it is therefore unlikely that this disease is caused by biotin deficiency. Nor could this scaly dermatitis be ascribed to an essential fatty acid deficiency. Serum and adipose tissue fatty acids resembled each other and reflected the fatty acid composition of the diet.

Adipose Tissue↗
PubMed1981

Coagulation and fibrinolysis study in systemic lupus erythematosus: haematological, urinary and tissue parameters.

Haematochemical, urinary and tissue parameters were examined in the elaboration of the coagulation and fibrinolysis profile in 33 cases of systemic lupus erythematosus in different stages of the disease. Coagulation abnormalities varied from hypo- to hyper-coagulability, these being often associated in the same patient, either simultaneously or at different stages of the disease. Activation of coagulation, closely related to the immunological activity of the disease, was present in 80% cases in the acute stage, and 36% of those in the remission stage. The lupus-like anticoagulant was not much involved, and platelets were the prime figures in the haemostatic abnormalities of lupus, those being the preferred target of direct antibody activities, or possibly of immune complexes as well. Activation of the coagulatory cascade is not uncommonly accompanied by a thrombophilic tendency coupled with signs of consumption, this being the expression of a continuously stimulated haemostatic balance.

Autoantibodies↗
PubMed1976

Dental implants.

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Dental Implantation↗