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R Drozdz

Publications and source records attributed to R Drozdz.

At least 19 recordsLinked to original sources
PubMed1999

(D-(p-benzoylphenylalanine)13, tyrosine19)-melanin-concentrating hormone, a potent analogue for MCH receptor crosslinking.

A photoreactive analogue of human melanin-concentrating hormone was designed, [D-Bpa13,Tyr19-MCH, containing the D-enantiomer of photolabile p-benzoylphenylalanine (Bpa) in position 13 and tyrosine for radioiodination in position 19. The linear peptide was synthesized by the continuous-flow solid-phase methodology using Fmoc-strategy and PEG-PS resins, purified to homogeneity and cyclized by iodine oxidation. Radioiodination of [D-Bpa13,Tyr19]-MCH at its Tyr19 residue was carried out enzymatically using solid-phase bound glucose oxidase/lactoperoxidase, followed by purification on a reversed-phase mini-column and HPLC. Saturation binding analysis of [125I]-[D-Bpa13,Tyr19]-MCH with G4F-7 mouse melanoma cells gave a K(D) of 2.2+/-0.2 x 10(-10) mol/l and a B(max) of 1047+/-50 receptors/cell. Competition binding analysis showed that MCH and rANF(1-28) displace [125I]-[D-Bpa13,Tyr19]-MCH from the MCH binding sites on G4F-7 cells whereas alpha-MSH has no effect. Receptor crosslinking by UV-irradiation of G4F-7 cells in the presence of [125I]-[D-Bpa13,Tyr19]-MCH followed by SDS-polyacrylamide gel electrophoresis and autoradiography yielded a band of 45-50 kDa. Identical crosslinked bands were also detected in B16-F1 and G4F mouse melanoma cells, in RE and D10 human melanoma cells as well as in COS-7 cells. Weak staining was found in rat PC12 phaeochromocytoma and Chinese hamster ovary cells. No crosslinking was detected in human MP fibroblasts. These data demonstrate that [125I]-[D-Bpa13,Tyr19]-MCH is a versatile photocrosslinking analogue of MCH suitable to identify MCH receptors in different cells and tissues; the MCH receptor in these cells appears to have the size of a G protein-coupled receptor, most likely with a varying degree of glycosylation.

Amino Acid Sequence↗
PubMed1998

gamma-Glutamyltransferase dependent generation of reactive oxygen species from a glutathione/transferrin system.

In the presence of molecular oxygen and iron or copper ions, a number of antioxidants paradoxically generate reactive oxygen species (ROS) leading to free radical damage of nucleic acids and oxidative modification of lipids and proteins. The present work demonstrates that the combination of three components, which are often considered as part of an antioxidant protection system, can generate ROS. Purified human gamma-glutamyltransferase (GGT) in the presence of 2 mM glutathione (GSH) and 80 microM transferrin, as an iron source, at pH 7.4 generates ROS, as measured by chemiluminescence of luminol. Initiated by the addition of purified GGT, generation of ROS reached a maximal rate in the first 6 min. Intensity of the chemiluminescence was only slightly enhanced by addition of 200 microM hydrogen peroxide. Generation of ROS was also investigated in transfected V79 cells expressing human GGT. In comparison with GGT negative V79 cells, only recombinant cells expressing a high level of GGT on the cell membrane were able to generate ROS. Generation of ROS in these cells reached a maximum within 2 min and was enhanced by 200 microM hydrogen peroxide. We further confirmed the hypothesis that cysteinylglycine (CysGly), a product of GGT/GSH reaction, identified by high-performance liquid chromatography, but not GSH, was responsible for ROS formation initiated by the reductive release of iron from transferrin. These data clearly indicate that under physiological conditions, GGT is directly involved in ROS generation.

Animals↗
PubMed1997

Evidence for B cell-mediated activation of V delta 1+ T lymphocytes during progression of HIV infection.

Progression of HIV-induced immunodeficiency is associated with both B cell activation and an increased proportion of Vdelta1+ T cells in PBL. To examine whether the peripheral expansion of Vdelta1+ cells is driven by activated B cells, we isolated CD19+ PBL from HIV+ individuals at different stages of infection and used them to stimulate Vdelta1+ T cell clones. The Vdelta1+ T cell clones were isolated from HIV+ individuals and selected on the basis of cytotoxic activity and IFN-gamma expression in response to lymphoblastoid cell lines (LCLs) established from patients with AIDS (AIDS-related LCLs) but not LCLs of HIV- donors. Peripheral blood B cells from HIV+ patients induced IFN-gamma expression in these Vdelta1+ clones, and their stimulatory ability was associated with up-regulated expression of the CD38 activation Ag and with a 6- to 10-fold increased spontaneous Ig production. Stimulation of CD19+ PBL from HIV+ individuals with cross-linked anti-CD40 mAb or rgpl20 further augmented induction of IFN-gamma expression in the Vdelta1+ cells. The isolated Vdelta1+ T cell clones expressed the Jdelta1 gene segment, but differed in Vgamma gene segment usage and in the junctional region of TCR-delta chains, indicating Vdelta gene-determined recognition. These results provide evidence that the peripheral expansion of Vdelta1+ cells in HIV infection is associated with phenotypic and functional alterations of B cells, due to chronic activation during progression to AIDS.

ADP-ribosyl Cyclase↗
PubMed1996

Apolipoprotein E is highly susceptible to oxidation by myeloperoxidase, an enzyme present in the brain.

Apolipoprotein E, the most common apolipoprotein found in the brain, is linked to several pathologies like Alzheimer's disease. Apolipoprotein E directly binds to beta-amyloid with a strong affinity. Myeloperoxidase, a protein secreted by neutrophils and involved in the inflammatory process, is also present in the brain. In vitro myeloperoxidase oxidation of recombinant human apolipoprotein E leads to fragmentation of the protein with low concentrations of hydrogen peroxide and polymerization with higher concentrations. Comparison with bovine serum albumin shows a higher susceptibility of apolipoprotein E to myeloperoxidase oxidation, which may have importance in the Alzheimer's disease process.

Alzheimer Disease↗
PubMed1995

Immunoglobulin cleavage by hypochlorous acid treatment.

IgA, IgG and IgM were cleaved by hypochlorous acid treatment. The apparent calculated molecular masses of three polypeptides obtained from IgA were 81.1. 25.8 and 13.9 kDa. The amounts of released IgA fragments were proportional to the amount of HOCl employed. At a HOCl:IgA molar ratio above 320:1, a profound degradation of IgA polypeptide chains occurred, resulting in a yellow-coloured product. The HOCl treatment of IgG resulted in similar effects, the liberation of three fragments, one of them being of a size slightly larger than that of the light chain (30.4 kDa). The treatment of IgM with HOCl also produced three fragments: one corresponding to the monomeric IgM molecule, the second to the light chain (26.4 kDa) and the third of a size smaller than the heavy chain. The optimal protein/HOCl ratios for the degradation of IgG and IgM were 375:1 and 808:1, respectively.

Dithiothreitol↗
PubMed1995

Melanin-concentrating hormone binding to mouse melanoma cells in vitro.

An analogue of human melanin-concentrating hormone (MCH) suitable for radioiodination was designed in which Tyr13 was replaced by Phe and Val19 by Tyr. The resulting monoiodinated [125I] [Phe13,Tyr19]-MCH radioligand was biologically active and led to the discovery of high-affinity binding sites on mouse B16-F1, G4F and G4F-7 melanoma cells. Saturation binding analysis with G4F-7 cells revealed 1090 MCH receptors per cell and a KD of 1.18 x 10(-10) mol/l. Receptors for MCH were also found on rat PC12 phaeochromocytoma cells, human RE melanoma cells and COS-7 cells. Competition binding analyses with other peptides such as alpha-MSH, NPY and PACAP demonstrated that MCH receptor binding is specific. rANF(1-28) was found to be a weak competitor of MCH, indicating topological similarities between MCH and rANF(1-28) when interacting with MCH receptors.

Amino Acid Sequence↗
PubMed1994

Computer modelling of polymer decomposition by active interactions with enzyme molecules. A simulation of RNA digestion by ribonuclease.

A model of 200 polymer molecules each 70 units of length with randomly located susceptible and resistant links was elaborated. The production of mono-, di-, tri-unit and other fragments in repeating random interactions of polymer (P) with the polymer--cleaving enzyme (E) was calculated. Analysis of the calculations performed that the polymer molecules with an initial count of 70-units disappeared, imitating the first order kinetics with a half-life of about 0.37 x 10(3) P/E interactions. The production of fragments 30-69 units long was small and the life of those molecules was limited to a range from 0.5 x 10(3) to 5 x 10(3) P/E interactions. The mean polymer length decreases to one third at 10(3) P/E interactions. The production of single-unit fragments followed a sigmoidal relationship. The first reaction period, with increasing number of single-unit fragments per 10(3) P/E interactions, corresponded to a decrease in the mean polymer length to about 10 units. Then the production of one-unit fragments decreased and stopped at about 10(5) P/E interactions. This model could be used for analysis of RNA fragmentation processes by any number of RNA-ribonuclease interactions. Further development of this model would be of help in understanding the effect of various nucleotide sequences on the RNA digestion process.

Animals↗
PubMed1993

Principles, main goals and methods of the nationwide program: "investigations on iodine deficiency and model of iodine prophylaxis in Poland".

The main reasons to start investigations on IDD in Poland as a nationwide project of the Ministry of Health and Welfare sponsored by the State Committee For Scientific Research and Foundation for Polish Science were: cessation of iodizing of kitchen salt in Poland in 1980, increase of the incidence of goitre in the population and hyperthyrotropinemia in newborns, results of the survey undertaken after Chernobyl disaster indicating an increase of goiter incidence (Nauman et al.) and results of the pilot study (Gutekunst, Gembicki, Kinalska and Rybakowa) indicating an increase of thyroid volume and diminishing of iodine excretion in urine of children in Kraków, Białystok ad Poznań regions. Therefore the main goals of the project were as follows: to evaluate IDD in Poland on the population basis, to map goiter incidence and iodine deficiency in geographic areas, to evaluate a voluntary model of iodine prophylaxis in Poland (20 mg of KI/kg of salt). The investigations were carried out in 19330 children (48.7% of boys and 51.3% for girls) in age group 6-13 years, attending 111 coeducational randomly selected schools from all the country. This number represents 0.35% of children subpopulation in the above age-groups. For practical purposes local coordinating centers at the relevant Departments of Endocrinology and Board of Coordinators were set up. The programme of survey included: filling the questionnaire by children's parents, thyroid palpation and classification according to WHO and ICCIDD criteria, thyroid volume determination by means of ultrasonograph Kontron Sigma 1 L with linear transducer 7.5 MHz, determination of iodine in casual morning urine sample using Sandell and Kalthoff method. Determination of iodine concentration in urine was performed in each case of goiter and in the same number of children without goiter. The results were segregated according to coordinating centers and according to 6 geographical areas of the country. The results were calculated according to the descriptive statistics using Student's test, Chi-square test F-test and Leven's test. The results segregated according to geographic areas were tested by means of analysis of variance using the linear model. The final results of the programme are presented in the next papers.

Adolescent↗
PubMed1993

Inactivation and denaturation of some proteins by enzyme system: myeloperoxidase, chloride and hydrogen peroxide.

Changes in biological properties of serum albumin, egg white lysozyme, human serum alpha-1 antiproteinase and human leukocyte ribonuclease in effect of interaction with the enzyme system composed of myeloperoxidase from human neutrophilic polymorphonuclear leukocytes, Cl- and H2O2 were investigated. All the studied proteins lost their biological functions and were denaturated, but the amounts of hydrogen peroxide necessary to produce these effects differed remarkably for each individual protein. The alpha-1 antiproteinase ability of binding to trypsin was abolished upon employing 1.2 mols of H2O2 per mol of alpha-1 antiproteinase. The lysozyme enzymatic activity was abolished when 1.4 mols of H2O2 per mol of lysozyme were employed. Albumin decreased its binding to specific antialbumin antibodies and entirely lost the binding properties when 2 mols and about 10 mols of H2O2 per mol of albumin were employed, respectively. On the other hand 18 mols of H2O2 per mol of human leukocyte ribonuclease were necessary to inactivate this enzyme. All the mentioned proteins were protected from losing their biological functions by excess of specific amino acids with affinity to hypochlorite: Alpha-1 antiproteinase by excess of N-acetylmethionine, lysozyme by N-acetylmethionine and N-acetyl glycyltryptophane, albumin by N-acetyl derivatives of methionine, cysteine, tryptophane and lysine, whereas ribonuclease was protected from denaturation by all above mentioned amino acid derivatives. None of the studied proteins was protected from denaturation by N-acetyl tyrosine, or phenylalanine.

Chlorides↗
PubMed1992

[Catalytic method of iodide ion determination in urine].

Kinetical catalytic method of iodide determination in urine was described. After wet ashing process in chloric/perchloric acid mixture kinetics of the trace iodide catalyzed reaction, cerium IV arsenic III was investigated. On the basis of nonlinear calibration curve determination of urine iodide in the range 0.1-5 microM/l was possible. High sensitivity range of iodide concentration and simplicity of performance predestinate described method for epidemiological studies in iodide deficiency regions.

Calibration↗
PubMed1991

[Evaluation of iodine levels in daily dietary intake and urine of persons participating in epidemiological studies in the Krakow macro-region after the disaster in Czernobyl and level of iodine in drinking water of that region].

Following the Czernobyl accident, an epidemiologic study was undertaken in which the daily iodine intake was estimated in 15% of the population studied. Iodine excretion was measured in single morning urine specimens. The iodine content was also assessed in the water form wells and in cow-milk at farms in randomly chosen villages in the region of Krynica and Nowy Sacz. On the basis of a 24-hour diet recall, the mass of each food product consumed daily was estimated for 483 persons in the Kraków voivodship (14.4% of the total population) and for 397 persons in the Nowy Sacz voivodship (15.8% of the total population). Using this data, the nutrient content of the daily diet was calculated for each studied individual. Measurements of iodine content in water and cow-milk show relatively lower iodine levels in the Nowy Sacz voivodship. The estimated value of the iodine content in milk (5.5 micrograms/100 g of milk) was considered in the estimates of the chemical composition of the daily diet of the inhabitants of this region. The mean values of the daily energy as well as the protein and calcium consumption in all subpopulations grouped with respect to domicile, age and sex, fell within the recommended daily allowances for these groups. The iodine content, while widely scattered, concentrated around low values. The median values of the iodine content in children of age 3-10 years, age 10-16 years and in adults, were 66%, 48% and 25-40% of the recommended daily allowances, respectively. No particular differences in the food intakes were observed between inhabitants of Kraków and Nowy Sacz voivodships. Nor were significant differences found in the urine iodine excretion in groups of these regions. The low iodine content in the daily food intake may be an essential factor in the ethiology of the increasing number of thyroid goiter.

Adolescent↗
PubMed1989

The receptor for alpha-melanotropin of mouse and human melanoma cells. Application of a potent alpha-melanotropin photoaffinity label.

The melanotropin (MSH) receptor of mouse B16-F1 melanoma cells was characterized by photoaffinity cross-linking, using a potent alpha-MSH photolabel, [norleucine4, D-phenylalanine7, 1'-(2-nitro-4-azidophenylsulfenyl)-tryptophan9]-alpha-melanotropin (Naps-MSH). Its monoiodinated form, 125I-Naps-MSH, displayed a approximately 6.5-fold higher biological activity than alpha-MSH. Scatchard analysis of the saturation curves with 125I-Naps-MSH revealed approximately 20,000 receptors/B16-F1 cell and an apparent KD of approximately 0.3 nM. Analysis of the cross-linked MSH receptor by sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed that a photolabeled band of approximately 45 kDa occurs in B16-F1, B16-F10, and Cloudman S91 mouse melanoma, as well as in human D10 and 205 melanoma but not in non-melanoma cells. The labeled 45-kDa protein had an isoelectric point of 4.5-4.9 as determined by two-dimensional gel electrophoresis. Treatment of the labeled 45-kDa protein of B16-F1 cell membranes by neuraminidase shifted the band to approximately 42 kDa. A similar band of about 42 kDa was also observed after receptor labeling of B16-W4 cells, a cell line with a decreased number of terminal N-linked neuraminyl residues. These results indicate that the labeled 45-kDa glycoprotein contains terminal sialic acid residues, explaining the low pI of this protein, and that it is characteristic for melanoma cells and hence part of the MSH receptor.

Affinity Labels↗
PubMed1988

Lysozyme oligomers as a molecular mass standard for sodium dodecyl sulfate-polyacrylamide gel electrophoresis.

Egg white lysozyme treated with hypochlorous acid links together producing di-, tri-, tetra-, and pentameric derivatives with molecular masses ranging from 14,300 to 90,500. Similar oligomeric products may be obtained by treating lysozyme color derivatives produced by labeling lysozyme with fluorescein, trinitrobenzenesulfonic acid and 2,4-dinitrofluorobenzene, with hypochlorous acid. The oligomeric lysozyme derivatives thus obtained consist of a mixture of proteins with molecular masses equal to multiples of 14,300 (lysozyme molecular mass). This mixture can be applied as a set of molecular mass standards suitable for determination of protein molecular masses on sodium dodecyl sulfate-polyacrylamide gel electrophoresis.

Electrophoresis, Polyacrylamide Gel↗
PubMed1988

Action of myeloperoxidase-hydrogen peroxide-chloride system on the egg white lysozyme.

The enzyme system composed of human neutrophilic myeloperoxidase (H2O2-oxidoreductase, EC 1.11.1.7), H2O2 and Cl-, at pH 4.5 interacts with egg white lysozyme (EC 3.2.1.17) in several stages. In the first stage, occurring at lysozyme to H2O2 molar ratio of 1:1.4-1.8, the lysozyme loses its enzyme activity but does not yield any derivative distinguishable from the native protein on polyacrylamide gel electrophoresis (PAGE). The second stage of oxidation begins at lysozyme to H2O2 molar ratio above 1:5, producing a change in the lysozyme spectrum at 260-290 nm, and yielding protein derivatives with molecular masses equal to multiples of 14.3 kDa, i.e. the lysozyme molecular mass. This implies that an excessive oxidation of lysozyme by the myeloperoxidase-H2O2-Cl- system produces cross-linking of lysozyme molecules to di-, tri-, tetra-, and pentameric structures. At lysozyme to H2O2 molar ratio exceeding 1:12 a water insoluble white product, which consists of a set of lysozyme cross-linked derivatives, is obtained.

Acetylcysteine↗