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Biomedical subjects

W Dobryszycka

Publications and source records attributed to W Dobryszycka.

At least 55 records · Page 3Linked to original sources

Hybrid protein containing heavy subunit of haptoglobin and light subunit of immunoglobulin G.

Dimeric hybrid protein molecule consisting of disulfide-linked beta (heavy) subunit of haptoglobin (Hp) and L (light) subunit of immunoglobulin G, was synthesized. Molecular mass of the hybrid was 62.0 kd, sedimentation constant B20 = 2.43. Hemoglobin binding activity of the beta X L hybrid as compared with that of native Hp accounted for 25%. In immunological cross-reactivity the hybrid was found to be deficient in some antigenic determinants present in Hp and in Hp beta chain. Hybridization carried out in three-component mixtures (Hp beta subunits, Hp alpha (light) subunits, IgG-L) showed, that besides reconstituted tetramers of Hp (2 alpha X 2 beta) always the hybrid beta X L was formed, even at an excess of Hp alpha, an excess of IgG-L prevented the formation of tetrameric molecules. Conformational similarity of Hp alpha and IgG-L as disulfide linked with Hp beta is reflected in the interaction of respective conjugates with hemoglobin.

Disulfides↗

Morphological and biochemical studies on experimental allergic encephalomyelitis in inbred lines of chickens.

An attempt to establish the relation between morphological and biochemical indices determining the inflammatory state in brain after induction of allergic encephalomyelitis in chickens was taken up. Symptoms of encephalomyelitis were accompanied by the changes within T and B lymphocyte population and by distinct increase of activity of trypsin inhibitor and content of sialic acid in blood serum.

Animals↗

Haptoglobin types in ovarian tumors.

Haptoglobin types were determined in 132 patients with cancer of ovaries and 114 patients with nonmalignant tumors of the ovaries, respectively. In comparison with a normal population significant increase in the frequency of Hp1 gene in the both pathological groups was observed. It was mostly reflected in a lower occurrence of haptoglobin type 2-2.

Adolescent↗

Intermediates in the reassociation of reduced haptoglobin.

Oxidative reassociation of alpha and beta subunits of human and equine haptoglobins as well as of two 2 alpha . 2 beta tetrameric hybrids made of subunits of each haptoglobin was studied following reduction of interchain disulphide bridges and also with isolated, PHMB-protected subunits in homologous and heterologous systems. Molecular mass and subunit composition of the intermediates appearing in the process of successive oxidation of -SH groups were determined by SDS-polyacrylamide-gel electrophoresis. The yield of subunit reassociation into homologous and heterologous tetramers 2 alpha . 2 beta was very high (75-80%) and the reassociated haptoglobins exhibited properties of native proteins in binding reactions with haemoglobin and with specific antibodies.

Animals↗

Hepatic binding of modified glycoproteins in some species of vertebrates.

1. Binding activities of hepatic extracts of the rat, chicken, frog and fish for 125I-labeled asialo-, agalacto-, and aN-acetylglucosamino-derivatives of orosomucoid and haptoglobin, were determined. 2. Hepatic receptors of the rat were found to bind preferably asialo-derivatives, those of the chicken agalacto-ones. 3. Hepatic receptors of lower vertebrates showed much lower affinity, in the case of the frog for all the modified glycoproteins whereas in the case of the fish with the exception of aN-acetylglucosamino-derivatives which were not bound at all. 4. Specific binding of derivatives of orosomucoid was higher than that of haptoglobin but equal in terms of molarity.

Animals↗

Di-, tri-, and tetrapeptide sequences in haptoglobin. Contribution to understanding of haptoglobin structure.

Amino acid sequences of haptoglobin and 11 proteins related and unrelated to haptoglobin were resolved into overlapping di-, tri-, and tetrapeptides. Comparison of the obtained peptides confirmed the existence of homology between haptoglobin and the family of serine proteases. The homology with light chain of immunoglobulins was relatively weak. A surprising similarity with concanavalin A was found. Tetrapeptide beta-turns (chain reversals), characterized by Chou & Fasman (1977, J. Mol. Biol., 115, 135-175) were compared with similar structures in light (alpha) and heavy (beta) subunits of haptoglobin.

Amino Acid Sequence↗

The effects of limited proteolysis by trypsin on human haptoglobin.

Trypsin digestion of haptoglobin resulted i four glycopeptides. The glycopeptides were characterized by amino acid composition and molecular weight, as determined by thin-layer chromatography, and sodium dodecyl sulphate-polyacrylamide gel electrophoresis in the presence or absence of 2-mercaptoethanol. Hemoglobin-binding capacity and immunological properties were investigated. glycopeptides I and II did not form an active complex with hemoglobin and they inhibited the reaction of haptoglobin with specific antiserum by over 70%. Glycopeptides III and IV showed 11 and 4% of the hemoglobin-binding capacity and 82 and 67% of antigenic reactivity of native haptoglobin, respectively. Glycopeptide IV contained three antigenic determinants, whereas glycopeptides III contained four, one of them being exposed by trypsin digestion. In crossed two-dimensional immunoelectrophoresis, glycopeptide III showed at least four components reacting with antihaptoglobin serum, and glycopeptide IV, two components.

Amino Acids↗

Effects of lead, copper, and zinc on the rat's lactate dehydrogenase in vivo and in vitro.

Following subacute intoxication of rats with Pb-, Cu-, and Zn-salts (separately or in mixture) for 5 weeks, the chelating agent D-penicillamine was administered for 3 weeks. In the course of the 3-month experiment, lactate dehydrogenase (LDH) was estimated in serum and in cytoplasmic fraction of the kidney. Pb2+ treatment resulted in an increase of LDH activity, Cu2+ in a slight decrease, whereas Zn2+ had no effect, respectively. Mixture of these metals caused a significant rise in the enzymatic activity. Seven weeks after the stoppage of the administration of toxic substances, altered LDH activity, both in serum and in kidney returned to normal. D-penicillamine treatment was found to accelerate a restoration of the enzyme activity. In the experiments in vitro, Cu2+ inhibited significantly the kidney LDH activity, Pb2+ and Zn2+ being 100- and 400-times less efficient, respectively. Cu2+ inhibition was reversed by D-penicillamine, whereas inhibition of LDH by Zn2+ or Pb2+ was irreversible.

Animals↗

Clinical usefulness of serum acute-phase reactants in patients with ovarian tumors.

Concentrations of the following acute-phase reactants (APR) were determined in the sera of patients with benign and malignant ovarian tumors: haptoglobin, ceruloplasmin, sialic acid, seromucoid (in sulphosalicylic acid supernatant), and trypsin inhibitory capacity. In patients with ovarian carcinomas significant increase (p less than 0.001) in all measured APR parameters as compared to healthy women and women with benign tumors was found. Moreover, the levels of haptoglobin, ceruloplasmin and trypsin inhibitory capacity were statistically lower (p less than 0.001) in nonmalignant than in malignant ovarian disease. No distinct statistical difference was confirmed between healthy controls and the benign tumor group as well as between ovarian carcinomas of Stages I--III and Stage IV.

Adenocarcinoma↗

Catabolism of desialylated glycoproteins during carcinogenesis and inflammation in rats.

Experiments were performed on rats injected with a malignant hepatoma (evoked by aflatoxin B1) or with inflammation induced by turpentine injection. On the 4th or 8th day after the injection, the following determinations were made: concentration of seromucoid, haptoglobin, sialic acid and fucose in blood serum; binding of asialo-glycoproteins by liver extracts; elimination of asialo-[125I]haptoglobin and asialo-[125I]orosomucoid from circulation. It was found that hepatoma and inflammation affected neither the activity of liver receptors for asialo-glycoproteins, nor the rate of asialo-glycoprotein elimination from circulation.

Animals↗

tRNA in developing human placenta.

Amino acid acceptor activity of tRNA in the human placenta as measured throughout gestation was found to be the lowest in post-term placenta. Aminoacylation of tRNA proceeded with maximum activity in the stage of formation of the placenta.

Female↗

Properties of the interspecies hybrids between haptoglobin alpha and beta subunits.

1. Subunits alpha isolated from human haptoglobin were recombined with beta subunits of equine haptoglobin, and vice versa. Both hybrid proteins were separated on electrophoresis in polyacrylamide gel into four bands with mobilities corresponding to tetramers 2alpha.2beta, trimers 2alpha.beta, and dimers alpha.beta, in addition to free subunits beta. 2. The binding ability of haemoglobin and the antigenic specificity of tetramers depended on the origin of beta subunit. 3. Reduction of native and hybrid proteins with 2-mercaptoethanol led to gradual formation of alpha.beta, alpha, and beta; the components 2alpha.beta and 2alpha appeared in trace amounts.

Animals↗

Microheterogeneity of mammalian haptoglobins in isoelectric focusing.

1. Human haptoglobin type 1-1, porcine haptoglobin, and equine haptoglobin were isolated and purified. 2. These haptoglobins were similar in polyacrylamide gel electrophoresis and in subunit structure but showed microheterogeneity in isoelectric focusing. 3. Isoelectric points of human haptoglobin as determined with photopolymerized gels were found to be 4.03-4.24, of porcine haptoglobin 4.0-4.30, and of horse haptoglobin 3.80-4.15, respectively. 4. Results obtained with chemically polymerized gels were 0.08-0.3 pH units higher. 5. Examined haptoglobins differed also in the ability of complex formation with hemoglobin, in sialic acid content and in antigenic specificity.

Animals↗