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Biomedical subjects

W Dobryszycka

Publications and source records attributed to W Dobryszycka.

At least 19 recordsLinked to original sources

[Pathophysiologic programming of cell death].

In multicellular organisms homeostasis depends on a balance between cell proliferation and cell death. In this review principles of the physiology of programmed cell death (apoptosis), i.e. biochemical features, involved genes and proteolytic enzymes, are described. Alterations in apoptosis contribute to the pathogenesis of a number of human diseases, including cancer, viral infections, inflammation, hematopoietic and immunological system defects (e.g. AIDS), neurodegenerative disorders. Specific effect on regulation of apoptosis might lead to new possibilities for treatment. Methods of quantitative determinations of apoptosis are discussed.

Acquired Immunodeficiency Syndrome

Biological functions of haptoglobin--new pieces to an old puzzle.

Haptoglobin, an "acute phase" protein, has different functions, which display genetic polymorphism. The complex of haptoglobin with haemoglobin is metabolized in the heptic reticuloendothelial system. Biosynthesis of haptoglobin occurs not only in the liver, but also in adipose tissue and in lung; providing antioxidant and antimicrobial activity. Changes in the measured concentrations of haptoglobin in serum may help to assess the disease status of patients with inflammations, infections, malignancy etc. (increases) as well as in haemolytic conditions (decreases). Haptoglobin plays a role in stimulation of angiogenesis and has highly potent cholesterolcrystallization-promoting activity. Probably the most important biological function of haptoglobin consists in the host defence responses to infection and inflammation, acting as a natural antagonist for receptor-ligand activation of the immune system.

Animals

Measurements of haptoglobin by the reaction with concanavalin A in sera of patients with ovarian tumours.

The concentration of haptoglobin in sera of healthy women and patients with non-malignant and malignant ovarian tumours was measured by two methods, i.e. complex formation with haemoglobin and complex formation with concanavalin A. High correlation (r = 0.74) between both the methods was found in the group of healthy women, but correlation coefficients were much lower in the group of non-malignant and malignant tumours (r = 0.42 and 0.37, respectively). Direct determinations of haptoglobin, and calculation of the ratio of haptoglobin bound to concanavalin A to haptoglobin bound to haemoglobin revealed statistically significant differences among the examined groups. Comparison of two methods of haptoglobin quantitation suggest that processes connected with ovarian disorders may alter the glycosylation of haptoglobin oligosaccharide chains.

Adult

[Cytokines, their receptors and inhibitors. Importance in laboratory diagnosis of rheumatoid arthritis].

The present paper reviews the literature on biological activities of human cytokines in homeostasis, as modulated by their secretion, expression of membrane-bound and soluble receptors as well as by means of other cytokines and specific inhibitors, respectively. The role of structure and properties of interleukins 1, 2, 6 and their receptors in pathophysiology and laboratory diagnostics of rheumatoid arthritis, is discussed. Methods of quantitative determination of cytokines are described.

Arthritis, Rheumatoid

Quantitation of human haptoglobin by ELISA system based on streptococcal haptoglobin receptors.

Streptococcus pyogenes cells with binding properties for human haptoglobin were used for quantitative determination of the acute phase protein, haptoglobin in various biological fluids. The S. pyogenes cells with protein surface antigen T4 served as solid phase in a microtitre ELISA system. After binding to the bacteria the amount of haptoglobin could be quantified by polyclonal or monoclonal antibodies. The constructed ELISA proved to be sensitive and correlated well with a conventional peroxidase method and with an immunoassay based on hemoglobin binding to haptoglobin.

Enzyme-Linked Immunosorbent Assay

Development of concanavalin A-enzyme immunosorbent assay for glycated haptoglobin using polyclonal and monoclonal antibodies.

Two-site lectin-haptoglobin-enzyme immunosorbent assay (L-Hp-ELISA), is described. Haptoglobin binding to Concanavalin A, immobilized to polystyrene microtiter plate, was estimated by anti-haptoglobin polyclonal and monoclonal antibodies conjugated with horse-radish peroxidase. The range of haptoglobin binding to Concanavalin A, measured by the L-Hp-ELISA was 25 to 300 ng/ml using polyclonal, and 50 to 600 ng/ml using monoclonal anti-haptoglobin antibodies, respectively.

Acetylation

Acute phase reactants and circulating immune complexes in patients with ovarian carcinoma.

Serum levels of haptoglobin (HP), sialic acid total (NAN) and lipid-bound (NAL), seromucoid (SER), its content in total protein (%SER), as well as circulating immune complexes (CIC), were measured in sera of women with ovarian carcinoma, prior to their treatment and through the course of chemotherapy, remission and recurrence of malignancy, respectively. Control groups consisted of healthy women and patients with benign tumors (ovarian cysts and uterine myomas). Pretreatment measurements of acute phase reactants discriminated cancers (FIGO stages I+II, III, IV) from healthy group, however differences between benign tumors and stages of ovarian cancer were not so distinct. Changes in the examined parameters (acute phase reactants) indicated satisfactorily a response to the administered chemotherapy and early signs of the progression of the disease. Because of great variations in serum CIC concentrations, they were found to be of no value either in diagnosis or in the surveillance of the disease status.

Acute-Phase Proteins

Characterization of haptoglobin-binding properties of streptococci of serological group G.

Two group G streptococcal cultures (G 10187, G 11122) with surface antigen T4 possess surface receptors for human haptoglobin (Hp). G 10187 additionally interacted with immunoglobulin G and albumin, G 11122 with fibrinogen and fibronectin. Binding of 125I-Hp 2-1 was time-dependent, saturable, reversible in the presence of unlabelled Hp and could be inhibited by unlabelled human-Hp 2-1, -Hp 2-2, -Hp 1-1, Hp-hemoglobin complexes and by Hp preparations from pigs, horses and rabbits. The Hp binding sites could be destroyed by heat treatment (95 degrees C) and by proteolytic treatment of the bacteria. Hp binding sites were solubilized from group G streptococcal surface by heat treatment of the bacteria at acid pH and subsequently isolated by affinity chromatography on Hp 2-1 sepharose. SDS-PAGE and Western blotting of the Hp binding proteins revealed numerous protein bands with 125I-Hp 2-1 binding activity. Specific antibodies against G streptococcal binding proteins prepared in chickens inhibited binding of 125I-Hp to group G and group A streptococci, but not to Actinomyces pyogenes.

Albumins

Enzyme immunoassay to measure low levels of haptoglobin in biological fluids.

A novel immunoenzymatic assay is described for the quantitation of human haptoglobin (Hp). Two binding sites on the Hp molecule, namely for hemoglobin (Hb) and for the specific antibody, are involved in the reaction. Hb adsorbed onto the polystyrene microplate binds Hp present in any biological fluid. The formed Hp-Hb complex is detected with horse-radish peroxidase conjugated with anti-Hp antibody. By means of this ELISA, Hp may be measured in the range of 5 to 150 micrograms/L. Comparison of the Hp-ELISA with two other methods of Hp determination resulted in correlation coefficients of 0.97 to 0.99. Intra- and inter-assay coefficients of variation ranged from 4.7 to 6.7%. Hp levels were measured in urine, cord serum, cerebrospinal fluid, amniotic fluid and saliva.

Amniotic Fluid

Monoclonal antibodies against human haptoglobin.

Three monoclonal antibodies: 2.36.71.41, 7.60.66.55, and 18.4.40. 80 to human haptoglobin 2-1 were produced, purified and characterized. The affinity constants ranged within 0.3-2.4 x 10(8) M-1. The monoclonal antibodies 7.60.66.55 and 18.4.40.80 reacted with beta subunit of haptoglobin, showed similar epitope affinities and epitope densities on main haptoglobin types. However, the epitope on the haptoglobin molecule for the monoclonal antibody 18.4.40.80 occupied somewhat more surface than that for the antibody 7.60.66.55. The monoclonal antibody 2.36.71.41 was able to bind both alpha and beta chains of haptoglobin. In ELISA affinity reactions this antibody achieved with haptoglobin 2-2 the plateau phase at absorbance values 15% higher than with haptoglobin 2-1, and 60% higher than with haptoglobin 1-1. End-point titration of the monoclonal antibody 2.36.71.41 against three haptoglobin types showed differences in titer, indicating distinct epitope densities.

Animals

The model of allergic encephalomyelitis of nonacute, phase course.

Allergic encephalomyelitis characterized by relapses and remissions was induced in chickens. The contents of M and G immunoglobulins in the serum was observed to increase at disease attacks and to decrease at its remissions. Similar correlation--though not so clear cut was noted with antitrypsin level. The usefulness of this model in pharmacotherapeutic investigations is discussed.

Animals

Properties of sulfanilazo-haptoglobin.

1. Tyrosine and two structural isomers of histidine residues in human haptoglobin were modified with diazotized sulfanilic acid. Sulfanilazo-derivatives of haptoglobin obtained by increasing the reagent/protein molar ration showed gradual decrease of peroxidase activity when complexed with hemoglobin. 2. Formation of haptoglobin derivatives with ten mono(sulfanilazo)-tyrosines and two mono (sulfanilazo)histidines resulted in the blockage of one out of six antigenic determinants, whereas immunoreactivity of the derivative with fourteen azotyrosines, one C-4, and two C-2 azohistidines was decreased by half. 3. Removal of sialic acid from oligosaccharide chains of haptoglobin made the molecule more accessible to diazotized sulfanilic acid. 4. Sulfanilazo-modification of tyrosine and histidine residues was practically of no effect in the reaction of haptoglobin with plant lectin, concanavalin A.

Haptoglobins

Clearance of certain modified haptoglobins from the rabbit circulation.

1. Human haptoglobin (Hp) type 2-1 was subjected to the sulfanilazo-modification of tyrosine and histidine residues, the removal of sialic acid, and the reduction of disulfide bonds (isolation of alpha 2, alpha 1, beta subunits), respectively. Radioactively labeled preparations were administered intravenously to rabbits. 2. Human Hp and isolated beta (heavy) chain disappeared from the circulation somewhat faster (half-lives = 72 and 67 h, respectively), than homologous rabbit Hp (half-life = 96 h). Hp light chains (alpha 2, alpha 1), devoid of oligosaccharide showed shorter half-lives of 27-19 h. 3. Treatment of Hp with diazotized sulfanilic acid resulted in an appreciable reduction of half-life to 21-11 h, as dependent on the number of modified residues. 4. Asialo-Hp, asialo-beta chain, and asialo-sulfanilazo-Hp were cleared rapidly from the circulation with half-lives of 5.5, 5.0, and 4.2 h, respectively. 5. These results suggest that in different pathways of Hp catabolism in vivo, polypeptide recognition markers in addition to carbohydrate ones, are involved.

Animals

Further characterization of haptoglobin binding to streptococci of serological group A.

Certain group A streptococci with surface antigen T 4 possess surface receptors for human haptoglobin (Hp). Binding of 125I Hp 2-1 to two representative group A streptococcal cultures could be inhibited by unlabelled Hp 2-1, Hp 2-2 and Hp 1-1 but not by the alpha 1, alpha 2 or beta chains of Hp. Hp complexes formed with equine hemoglobin and asialo-Hp also reduced 125I-Hp 2-1 binding to group A streptococci. Hp binding proteins could be solubilized from streptococcal surface by hot acid treatment of the bacteria and purified by subsequent affinity chromatography on human Hp 2-1 sepharose. The isolated Hp binding proteins specifically inhibited 125I-Hp 2-1 binding to group A streptococci and retained their 125I-Hp 2-1 binding activity in a dot binding assay on nitrocellulose membranes. SDS-PAGE and protein blots of Hp binding proteins developed with 125I-labeled Hp 2-1 revealed numerous high molecular weight proteins with 125I-Hp 2-1 binding activity.

Bacterial Proteins