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Y Burstein

Publications and source records attributed to Y Burstein.

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

Restoration of immunological responses by THF, a thymic hormone, in mice infected with murine cytomegalovirus (MCMV).

Cytomegalovirus causes T cell immune impairment in infected mice, reflected by a decreased response to the T cell mitogens PHA and Con A, and reduction of Con A-induced IL-2 secretion. Concomitantly, a marked increase in the spleen weight of infected mice was found. Histological examination of the liver revealed focal hepatitis. These signs of infection lasted from day 5 to day 14 after infection when mice slowly started to recover. Systemic treatment of MCMV-infected mice with thymic humoral factor (THF) resulted in a reconstitution of the mitogenic responses, IL-2 secretion, normalization of spleen weight and recovery of liver inflammation. Unlike other thymic hormones, THF did not affect interferon synthesis and NK cytotoxicity in infected mice. It is concluded that THF restores immune competence of mice immunosuppressed as a result of MCMV infection, through modulation of the T cell compartment.

Animals↗
PubMed1987

Abnormalities of cellular immunity and natural killer cells in Gaucher's disease.

Gaucher's disease (GD) which is a congenital defect characterized by the accumulation of glucocerebroside in cells of the reticulo endothelial system, is associated with malignancies of the lymphoid system such as multiple myeloma, chronic lymphatic leukemia, as well as acute leukemia of childhood. We report the immunological profile of the T-cell system in GD patients and in GD carriers. We found a variable response to lectins stimulation (PHA, Con A, PWM in various concentrations) which supports the hypothesis that a persistent antigenic stimulation in GD affects all components of the immune system of those patients. A highly significant decrease in the number of NK cells was also found, which might be a predisposing factor to the increase in malignant B and other lymphoid cell proliferations described in patients with GD.

B-Lymphocytes↗
PubMed1986

Partial amino acid sequence of porcine elastase II. Active site and the activation peptide regions.

The partial amino acid sequence of porcine elastase II, isolated from crude trypsin Type II, was determined. The enzyme consists of two polypeptide chains, a light chain composed of 11 residues, and a heavy chain (Mr = 23 500) with four intrachain disulfide bridges; the two chains are held together by one interchain disulfide bond. Elastase II was fragmented into several peptides by chemical cleavages with CNBr at the two methionine residues, 99 and 180 (chymotrypsinogen numbering), and with hydroxylamine at the peptide bond following DIP-Ser195. About 50% of the sequence was determined and the positions of 120 amino acids were located, including the light chain residues and most of the active site residues. The partial sequence shows 64% difference between porcine elastase II and elastase I and only 26% difference between porcine elastase II and bovine chymotrypsin B.

Amino Acid Sequence↗
PubMed1986

Treatment of congenital immune deficiencies with a thymic hormone--thymic humoral factor.

Five infants with congenital immune defects are presented. Three had various combined immune deficiencies (CID) and two had thymic deficiencies only. As bone marrow or thymus transplantations were not feasible in these patients, we attempted treatment with thymic humoral factor (THF), a thymic hormone, by daily i.m. injections during biweekly courses. In one CID patient, a partial improvement in immune indices and temporary clinical improvement were achieved. In the other two, THF did not arrest the patients' demise. The two patients with thymic dysplasia benefitted repeatedly from THF treatment, as exemplified by the disappearance of wasting, diarrhea and infections and by reconstitution of T cell parameters. Nevertheless, the patients relapsed after prolonged periods without THF administration. We therefore propose the administration of long-term, continuous or intermittent thymic hormone replacement therapy in infants with congenital thymic defects. Early diagnosis and immediate institution of treatment will probably improve prognosis.

Female↗
PubMed1985

Non-immune interaction of erythrophilic IgG fractions with human red blood cells.

Immunoglobulin G was separated on cellulose phosphate column to afford four distinct protein fractions (CP-I, II, III and IV). 125I-labeled fractions CP-III and CP-IV were found to be capable of binding specifically to normal human erythrocytes. The effect of the four fractions on osmotic resistance of red blood cells (RBC) was studied. RBC were obtained from eight patients with hereditary spherocytosis (HS), from a single parent of two non-related patients, and from five normal donors. RBC fragility of normal and one parent were unaffected by any of the immunoglobulin fractions. In contrast, a small but significant decrease in osmotic resistance was observed when RBC from HS patients and the second parent were incubated with protein fractions CP-III and CP-IV.

Adult↗
PubMed1985

Digestion of elastin by porcine pancreatic elastase I and elastase II.

Elastin was fully solubilized by digestion with elastase I or elastase II. Each digest was separated into high-molecular weight and low-molecular weight fractions that were characterized by the correspondence to their amino acid content, N-terminal sequence and C-terminal amino acids. It was found that although the relative amount of amino acids in the low-molecular weight fraction obtained by digestion with elastase I was lower than in digestion with elastase II, no major difference in the type of bonds cleaved in the low- or high-molecular weight fractions of each digest could be seen. There is, however, a remarkable difference in the type of bond cleaved by the two enzymes. While elastase I cleaves mostly Ala-Ala and also Ala-Gly bonds, elastase II hydrolyzes Leu-Ala, Leu-Gly, Phe-Ala, Phe-Gly and Tyr-Ala, Tyr-Gly bonds. Theoretical calculations led us to suggest both digests are composed of cross-linked peptides that vary not only in the molecular size but also in the number of cross-links found in peptides of the same size.

Amino Acid Sequence↗
PubMed1985

Association of Gaucher's disease and lymphoid malignancy in 2 children.

2 cases of acute lymphoblastic leukaemia (ALL) of childhood in association with Gaucher's Disease (GD) are presented, which are the first to be described. One of them is a common non-B non-T cell ALL and the other is at T-cell ALL. The association of GD with benign and malignant B-cell proliferation has recently been described. It is suggested that chronic stimulation of the immune system by the accumulated glucocerebroside may predispose to B cell proliferation.

B-Lymphocytes↗
PubMed1984

Isolation and partial purification of a clonidine-displacing endogenous brain substance.

A new compound, designated clonidine-displacing substance (CDS), has been isolated from calf brain by ion-exchange chromatography, zone electrophoresis and high-performance liquid chromatography. CDS binds specifically to alpha 2-adrenergic receptors in rat brain and human platelet membranes, as measured in direct binding experiments using [3H]clonidine and [3H]yohimbine respectively. Unlike clonidine or other alpha 2-agonists, CDS does not affect basal levels of adenylate cyclase in human platelets at the highest concentrations obtainable. The apparent molecular mass of the compound is estimated to be 500 +/- 50 Da, as determined by gel-filtration chromatography on Sephadex G-15. The new compound is thermostable, not affected by proteolytic enzymes, such as trypsin, chymotrypsin, pronase, papain and pyroglutamase, or by boiling in 0.2 M HCl for 5 min. It does not bind to alpha 1-receptors in rat brain or to beta-adrenergic receptors in turkey erythrocytes, since it is unable to displace [3H]prazosin and [125I]cyanopindolol from alpha 1 and beta-receptors respectively.

Adenylyl Cyclase Inhibitors↗
PubMed1984

Isolation of an endogenous clonidine-displacing substance from rat brain.

An endogenous substance which specifically displaces clonidine, yohimbine and rauwolscine from rat brain alpha 2-adrenergic receptors, has been isolated. The new compound, designed clonidine-displacing-substance (CDS), has been partially purified by ion exchange chromatography, zone electrophoresis and high performance liquid chromatography (HPLC). CDS binds specifically to alpha 2-adrenergic receptors by competing with either alpha 2-adrenergic agonists or alpha 2-antagonists, but has no effect on the specific binding of [3H]prazosin to alpha 1-adrenergic receptors in rat brain membranes. In the course of isolation, CDS was shown to be neither the endogenous neurotransmitter (-)norepinephrine (NE) nor the guanyl nucleotide GTP which lowers the specific binding of alpha 2-agonists to the alpha 2-adrenergic receptors.

Animals↗
PubMed1983

Synthetic leader peptide modulates secretion of proteins from microinjected Xenopus oocytes.

To investigate the role of the leader peptide in modulating secretion from living cells, we injected a synthetic peptide into Xenopus oocytes. The peptide consisted of the NH2-terminal leader sequence of mouse immunoglobulin light chain precursor. We found that the leader peptide has two different roles in regulating secretion from the oocytes. First, it competitively inhibits the synthesis of secretory and membrane proteins but not of cytoplasmic proteins. The inhibition occurs both with oocyte proteins and with proteins directed by coinjected myeloma mRNA. The inhibition reaches a maximum 2 hr after injection and decays within 3 hr. It appears to be mediated through the cell membrane, because 125I-labeled leader peptide segregates into the membrane fraction of microinjected oocytes simultaneously with the interference with methionine incorporation. A second role of the microinjected leader peptide is to induce a rapid acceleration in the rate of export of secretory proteins from the oocyte. The maximal enhancement effect is obtained upon injection of 50 ng of leader peptide per oocyte. It is not merely due to the small size, negative charge, or hydrophobicity of the peptide, because enhanced secretion does not occur when glucagon, poly-L-glutamic acid, or Triton X-100 is injected. Furthermore, immunoreaction of the peptide with specific antibodies prior to microinjection prevents the accelerated export. Our observations indicate that in Xenopus oocytes, the leader peptide is involved in both translocation and later step(s) in the secretory pathway.

Animals↗
PubMed1982

Somatic DNA rearrangement generates functional rat immunoglobulin kappa chain genes: the J kappa gene cluster is longer in rat than in mouse.

The kappa immunoglobulin (Ig) genes from rat kidney and from rat myeloma cells were cloned and analyzed. In kidney DNA one C kappa species is observed by Southern blotting and cloning in phage vectors; this gene most likely represents the embryonic configuration. In the IR52 myeloma DNA two C kappa species are observed: one in the same configuration seen in kidney and one which has undergone a rearrangement. This somatic rearrangement has brought the expressed V region to within 2.7 kb 5' of the C kappa coding region; the rearrangement site is within the J kappa cluster which we have mapped. The rat somatic Ig rearrangement, therefore, closely resembles that seen in mouse Ig genes. In the rat embryonic fragment two J kappa segments were mapped at 2 and 4.3 kb 5' from the C kappa coding region. Therefore, the rat J kappa cluster extends over about 2.3 kb, a region much longer than the 1.4 kb of the mouse and human J kappa clusters. In the region between C kappa and the expressed J kappa of IR52 myeloma DNA, and XbaI site present in the embryonic kappa gene has been lost. A somatic mutation has therefore occurred in the intervening sequence DNA approx. 0.7 kb 3' from the V/J recombination site. Southern blots of rat kidney DNA hybridized with different rat V kappa probes showed non-overlapping sets of bands which correspond to different subgroups, each composed of 8-10 closely related V kappa genes.

Animals↗
PubMed1982

Recent duplication and germ-line diversification of rat immunoglobulin kappa chain gene joining segments.

Sequence determination of the joining segment gene (J) cluster in the kappa chain (J kappa) in the embryonic context demonstrates that rat genome contains seven J kappa gene segments that expanded from an ancestral cluster of five J kappa genes. The rat J segments are separated by about 300 base pairs (bp) and are flanked 5' by the presumed variable region (V)/J recombination signal sequence and 3' by the RNA splicing signal. Two of the J gene segments designated J2A and J2B and their 5'-flanking spacer DNA bear striking homology to J2 and its 5'-flanking spacer. Thus, the unit of duplication was the entire J kappa coding region and 5' noncoding spacer (345 bp). The duplication probably occurred as two separate unequal crossing-over (UXO) events. The first UXO event can be confined to recombination within an identical stretch (14 bp long) located at the 3' ends of the coding regions of J1 and J2. The second event could involve a longer segment (372 bp) of tight homology generated by the first UXO event, thus increasing the probability of repeated expansion of the same DNA segment. The sequence homology among the rat duplicated segments (98-99%) is larger than the homology between the corresponding rat and mouse segments (89%), showing that the rat J kappa gene expansion must have occurred after rat and mouse divergence 10 X 10(6) yr ago. We estimate that the first and second UXO events occurred 2 X 10(6) and 1 X 10(6) yr ago, respectively. J3 of rat and mouse share the same mutation (G leads to C) in the RNA splicing signal that presumably inactivates J3. This mutation preceded divergence of the two species. A mutation in the first nucleotide of codon 96 has occurred in both duplicated segments, the only position along 345 bp where J2, J2A, and J2B differ from each other. This results in three different amino acids at position 96 not present in any other J kappa. These mutations are physiologically significant because they diversify the third complementarity-determining region (CDR3) and, thus, may reflect selective pressure to increase antibody diversity. The germ-line diversification of CDR3 was exercised within the last 1-2 X 10(6) yr.

Amino Acid Sequence↗
PubMed1981

Inhibition of porcine elastase II by chicken ovoinhibitor.

Interaction of porcine elastase II with native and modified chicken egg-white ovoinhibitor was studied by determining the residual activity of the partially inhibited enzyme and by direct measurement of the stoichiometry of interaction using affinity chromatography, electrophoresis and gel filtration. It was found that the chymotrypsin binding site that is not modified by mild oxidation with N-chlorosuccinimide (Shechter et al., Biochemistry, (1977) 16, 992-997) is capable of binding elastase II as well. The binding of chymotrypsin and elastase II is mutually exclusive and the affinity of chymotrypsin is stronger. Binding of 2 mol trypsin as 1 mol elastase I by ovoinhibitor does not interfere with the binding of elastase II. There is also an indication that the second binding site for chymotrypsin is capable of forming a complex with an additional molecule of elastase II, but the binding is so weak that it could be detected only by electrophoresis.

Amino Acids↗