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At least 721 records · Page 40Linked to original sources
PubMed1987

Does the degree of polymerization of haptoglobin influence the results of the radial immunodiffusion assay?

The degree of polymerization of haptoglobin (Hp) phenotypes 2-1 and 2-2 was studied. In individual samples the degree of polymerization tends to be positively correlated with the Hp concentration as determined by the radial immunodiffusion technique (RID), while an inverse relationship between the size of Hp polymers and the Hp concentration in RID was expected. After reductive cleavage of Hp, the apparent Hp concentration became higher in individual samples with different degrees of polymerization; the shift to higher values appeared to be independent of the degree of polymerization in samples of phenotypes Hp 2-1 and Hp 2-2. Consequently, the degree of polymerization as such does not have an impact on the outcome of RID at a technical level.

Electrophoresis, Polyacrylamide Gel↗
PubMed1994

Monosaccharide composition of haptoglobin in liver diseases and alcohol abuse: large changes in glycosylation associated with alcoholic liver disease.

Liver damage through prolonged intake of high amounts of alcohol is a serious problem that affects many members of the population. The aim of this study was to investigate changes in the glycosylation of haptoglobin (Hp) resulting from alcoholic liver diseases. The monosaccharide composition was measured in Hp isolated from 48 healthy individuals, 15 alcohol abusers (AA); 25 patients with alcoholic liver disease, including those with alcoholic cirrhosis (ALD/AC), and 17 other patients with either chronic active hepatitis (AH) or primary biliary cirrhosis (BC). Fucose was elevated per mol of Hp in 70%, 44%, and 33% of the individuals in the ALD/AC, BC and AA groups, respectively. Fucose was not elevated in the AH group. N-acetylglucosamine was also elevated in the ALD/AC group. Expressing results per 3 mol of mannose suggested the presence of higher branching with increased fucose content in Hp from all the abnormal groups except the AH group. More structural information is required to develop the diagnostic potential of carbohydrate measurements of Hp in alcoholic liver diseases.

Acetylglucosamine↗
PubMed1995

Components of biological variation in plasma haptoglobin: relationships to plasma fibrinogen and immune variables, including interleukin-6 and its receptor.

We investigated the components of biological variation, including seasonality, in plasma haptoglobin (Hp) levels and the relationships between plasma Hp and interleukin-6 (IL-6), soluble IL-6 receptor (sIL-6), sIL-2R, fibrinogen (Fb) and absolute number of peripheral blood mononuclear cells, such as leukocytes, neutrophils, monocytes, lymphocytes, CD4+, CD8+, CD25+ T cells and CD20+ B cells. Monthly blood samples were taken from 26 normal volunteers during one calendar year. The estimated inter- and intra-individual C.V. values for plasma Hp were 27.9% and 20.0%, respectively; the index of individuality was 0.72. No significant seasonal rhythms could be detected in plasma Hp levels. The yearly mean values in plasma Hp were significantly and positively related to those in plasma Fb, absolute number of leukocytes, neutrophils, CD4+ T cells and the CD4+/CD8+ T cell ratio. 49.0% of the variance in the yearly mean values of plasma Hp could be explained by variances in serum IL-6 and number of CD4+ (positively related) and CD8+ (negatively related) T cells. There were significant and positive time relationships between plasma Hp, on the one hand, and plasma Fb, sIL-6R, sIL-2R and number of leukocytes, neutrophils and monocytes, on the other. A smaller part of the within-subject variability in plasma Hp (i.e. 6.0%) could be explained by serum sIL-6R and sIL-2R. It is concluded that there are (1) important between-subject differences in the homeostatic setpoints of plasma Hp, which are related to those in plasma Fb and in immune status and (2) significant within-subject, time relationships between plasma Hp and indicators of immune activation and plasma Fb.

Adult↗
PubMed1984

Characterization of human haptoglobin cDNAs coding for alpha 2FS beta and alpha 1S beta variants.

A human liver library, derived from a heterozygous (Hp2-1) donor, has been used to isolate cDNA clones coding for the haptoglobin (Hp) alpha 1S beta and alpha 2FS beta variants. DNA sequencing has shown that the two variants are identical except for the alpha F duplicated segment in Hp alpha 2FS beta. Four nucleotide changes have been found between the phenotypically different F and S regions of the Hp alpha 2 gene, resulting in an Asp,Lys/Asn,Glu substitution.

Alleles↗
PubMed1988

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↗
PubMed1976

Investigation of the apparent delay in mobility of albumin, alpha-1-antitrypsin, haptoglobin 1-1 and fibrinogen in electroimmunodiffusion.

Differences in mobility of free and complex-bound antigen molecules during electrophoresis in antibody-free and antibody-containing agarose gel were investigated with albumin, alpha-1-antitrypsin, haptoglobin and fibrinogen. The combination of line electrophoresis and one-dimensional single electroimmunodiffusion as designed for this purpose is described. Differences in time between the start of line electrophoresis and that of rockets, in view of their influence on the formation of the line precipitate, served as reference values. Three basic types of morphology of the line precipitate in the area of possible interaction between line and rocket precipitation were distinguished: total interruption, partial interruption and no interruption. By means of the time differences indicator system it was found that this apparent reduction in mobility during electroimmunodiffusion of the antigens tested was reversely proportional to the electrophoretic mobility of free antigens.

Albumins↗
PubMed1987

Polyethylene glycol enzyme immunoassay for screening anti-haptoglobin monoclonal antibodies.

An enzyme immunoassay for the screening of anti-haptoglobin activities in supernatants of hybridoma cell cultures is described. The sandwich technique was greatly improved by the addition of 2% polyethylene glycol 6000 to all the reagents. It allowed a six-fold shortening in the incubation time compared with the standard method without sacrificing either sensitivity or accuracy.

Antibodies, Monoclonal↗
PubMed1994

Determination of haptoglobin expression in IL-6 treated HepG2 cells by ELISA and by RNA hybridization--evaluation of a quantitative method to measure IL-6.

Interleukin-6 (IL-6) is known to be an important modulator of acute phase (AP) protein expression in hepatocytes both in vivo and in vitro. In the present study the inducing activity of IL-6 on the expression of the AP protein haptoglobin (HP) by the human hepatoma cell line HepG2, has been evaluated. HP mRNA inducibility was analysed by Northern and slot-blot hybridization, while HP protein was detected by means of an ELISA procedure. A dose-response relationship from 0.3 to 4.8 ng/ml of a human recombinant IL-6 preparation derived from a Chinese hamster ovary (CHO) cell line was observed after 48 h of treatment. Comparable results were obtained by analysing both HP mRNA expression and HP protein secretion. Detectable induction of HP protein secretion was observed with as little as 25 pg/ml of IL-6. The effect of IL-6 was potentiated by dexamethasone, while an inhibition on HP mRNA inducibility could be prevented by lowering the foetal calf serum (FCS) concentration to 1%. Preliminary data indicate that neither IL-1 beta nor TNF-alpha were able to induce significantly HP mRNA expression and protein secretion. The activity ratio between two IL-6 preparations (from CHO and E. coli cells) obtained with a conventional IL-6 bioassay (i.e., T1165 cell growth assay) was comparable to that obtained in the induction of HP expression. The nominal specific activity of the CHO-derived IL-6 was two to three times higher with both responses.

Animals↗
PubMedDate not supplied

Relationships between basal hypothalamic-pituitary-thyroid-axis activity and plasma haptoglobin levels in depression.

The present study was carried out in investigate the relationship between basal hypothalamic-pituitary-thyroid (HPT)-axis function and the acute phase (AP) response in depression. Toward this end, the authors measured serum concentrations of basal thyroid-stimulating-hormone (TSH), free thyroxine (FT4) and free triiodothyronine (FT3), and plasma levels of an AP protein, i.e. haptoglobin (Hp) in 38 depressed in-patients and in 11 normal controls. In depression, basal TSH was significantly and negatively related to Hp values, whereas in normal controls a trend toward a positive correlation between both factors was found. Depressed patients with increased Hp levels (> or = 250 mg/dl) showed significantly lower basal TSH levels than patients with normal Hp levels. No significant correlations were found between Hp plasma levels and either FT4 or FT3 serum concentrations. The results support the hypothesis that lower TSH secretion in major depression may be related to the AP response in that illness, and may constitute an expression of a coordinated neuroendocrine-immune response to nonthyroidal illness.

Acute-Phase Reaction↗
PubMed1995

Relationship between insulin-dependent diabetes mellitus (IDDM) and non-insulin-dependent diabetes mellitus: beta-cell function, islet cell antibody, and haptoglobin in parents of IDDM patients.

To examine the relationship between non-insulin-dependent diabetes mellitus (NIDDM) and insulin-dependent diabetes mellitus (IDDM), we studied beta-cell function, HLA type, and serologic markers of IDDM and NIDDM in the parents of IDDM patients. Fifty-two parents of 33 IDDM patients were examined in terms of islet-cell antibody (ICA) status, haptoglobin phenotype, HLA type, and insulin responses during an oral glucose tolerance test (OGTT). Twenty-seven parents were prospectively evaluated for up to 113 months. They were divided into the following three groups based on pattern of ICA positivity during the follow-up period: group 1, persistently positive ICA (n = 4); group 2, fluctuating ICA (n = 7); and group 3, persistently negative ICA (n = 16). Twenty-three percent (12 of 52) of the parents of IDDM patients had NIDDM, and 12% (six of 52) of the matched controls did. The prevalence of ICA in the parents (11 of 52, 21%) was greater than in normal controls (one of 112, P < .01). Diabetic parents tended to show a higher prevalence of ICA (six of 12, 50%) than nondiabetic parents (six of 40, 15%; P = .06). ICA-positive parents showed higher glucose levels and lower insulin responses than ICA-negative parents. Three of four parents in group 1 slowly progressed to an insulin-dependent state during 25 +/- 3 months of follow-up evaluation. Parents in group 2 and group 3 did not show any changes in glucose levels or insulin responses during the study.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Iron, transferrin, and haptoglobin levels after a single bout of exercise in men.

Twelve, healthy male university student volunteers, between the ages of 20 and 23, were studied. All subjects were considered normal after cardiopulmonary and electrocardiographic examination. The maximal aerobic capacity (Vo2 max) of each subject was determined. The exercise programmes were performed on a mechanically braked Monark cycle ergometer. The subjects were required to perform the three tests, one per week. Each subject had a catheter inserted in an antecubital vein and blood samples were drawn at rest and at the end of exercise. Before and immediately after each exercise session total proteins (TP), hematocrit (Hct), hemoglobin (Hb), and other hematological parameters were measured. Serum iron (Fe), transferrin (TRF), and haptoglobin (HPT) were also determined. Immediately after the end of the exercise (TPT, RST, and IET), TP, Hb, Hct, and RBC increased significantly. TRF and HPT concentrations remained unchanged and iron decreased significantly after maximum sustained test (RST).

Adult↗
PubMed1981

Haptoglobin polymorphism and its relationship to malaria infections in The Gambia.

The haptoglobin (Hp) status of the population of Keneba, The Gambia was investigated. Of the 825 persons examined 22.9% were ahaptoglobinaemic (HpO). The incidence of HpO was higher in the 209 persons showing malaria parasites in their blood (38.8%) than in non-parasitaemic individuals (17.5%). Children less than two years old had low incidences of HpO except in the first two months of life. After two years the incidence rose with little tendency to change in older age groups. No correlations were seen between HpO and sex, anaemia or sickle cell trait. However, a positive correlation was found with malariometric indices in all age groups except the two to four years. The Hp of individuals was found to be unstable suggesting that in Africans it is a poor genetic marker. These results indicate that Hp is utilized in removing free haemoglobin liberated intravascularly, during malaria infections and that although this is a major cause of the high incidence of HpO in The Gambia, other factors are also important.

Adolescent↗
PubMed1986

Human haptoglobin adsorption by a total internal reflection fluorescence method.

Haptoglobin (Hp) is one of the major protein constituents of plasma. Three different forms are found in the population. The 1-1 and 2-2 forms adsorb similarly onto hydrophobic silica [treated with dimethyl dichlorosilane (DDS)] and onto clean silica, although the affinities on the silica surface are lower at 60 minutes contact time. The two forms desorb differently from silica, but desorb similarly from DDS-silica. Adsorption is less reversible on the hydrophobic surface. Due to its adsorbtion tendencies and its high concentration in plasma, the adsorption of Hp may be important in blood interaction at solid-liquid interfaces.

Adsorption↗
PubMed1992

Higher alpha 1-antitrypsin, haptoglobin, ceruloplasmin and lower retinol binding protein plasma levels during depression: further evidence for the existence of an inflammatory response during that illness.

Recently, a few reports have shown that severe depression may be associated with higher levels of positive acute phase proteins (APPs), such as haptoglobin (Hp), alpha 1-acid glycoprotein (alpha 1S) and lower levels of negative APPs (visceral proteins), such as albumin (Alb) and transferrin (Tf). In order to reassess whether depression is related to alterations in the expression of plasma APP concentrations, we measured in 84 normal controls and depressed inpatients positive APPs such as Hp, alpha 1-antitrypsin (alpha 1AT), hemopexin (Hpx), ceruloplasmin (Cp), complement component C3C and one visceral protein, i.e., retinol binding protein (RBP). We found increased plasma concentrations of Hp, alpha 1AT, and Cp in major depressed subjects as compared with healthy controls, with minor depressives exhibiting an intermediate position. RBP was significantly lower in minor and major depressives than in normal controls. The disorders in these proteins were rather sensitive (62%) for major depression, with a specificity equalling 96%. Our findings are compatible with the hypothesis that major depression may be accompanied by inflammatory changes with higher levels of positive APPs (i.e., alpha 1AT, Hp, Cp, alpha 1S) and lower levels of visceral proteins (i.e., RBP, Tf, Alb).

Acute-Phase Reaction↗
PubMed1992

Bovine haptoglobin: single radial immunodiffusion assay of its polymeric forms and dramatic rise in acute-phase sera.

Using purified bovine haptoglobin (Hp) and specific antisera, a single radial immunodiffusion (SRID) assay method has been developed to measure the serum Hp level in cattle. Bovine Hp is a highly polymerized protein showing heterogeneous molecular forms in serum. After treatment with cysteine or glutathione, Hp was partially reduced to a homogeneous form, suitable for SRID assay. This method gives values comparable to those obtained by hemoglobin-binding capacity assay, and has the advantage of being simple and convenient. Although serum Hp was not detectable in healthy cattle, it was found more than 50-fold after invasive surgery, indicating that Hp is a characteristic acute-phase protein in cattle.

Acute-Phase Reaction↗
PubMed1995

Validation of immunoassays for bovine haptoglobin.

Haptoglobin (Hp) is an acute phase protein. The plasma concentration of Hp increases rapidly following tissue damage associated with infection and inflammation. Thus Hp levels could be used as a screening test for organic disease, an objective index of disease activity and response to therapy, or as a sign of microbial infection. Recently, an enzyme-linked immunosorbent assay for bovine Hp was described. We have now developed three different immunoassay formats for bovine Hp and report on their validation and relative value to the diagnosis of bovine disease. Hp levels measured using these three immunoassays were compared and contrasted with results obtained for Hp estimation as measured by the increase in the protection of peroxidase activity against acid inactivation following binding with bovine haemoglobin. The quantitative Hp immunoassays evaluated in the present study are simple, rapid, inexpensive, reproducible, and well suited for both field and laboratory use.

Animals↗
PubMed1987

Decay accelerating factor (DAF) peptide sequences share homology with a consensus sequence found in the superfamily of structurally related complement proteins and other proteins including haptoglobin, factor XIII, beta 2-glycoprotein I, and the IL-2 receptor.

Amino acid sequence data derived from tryptic peptides of the decay accelerating factor indicate that this complement regulatory protein contains a sequence with homology to the superfamily of structurally related complement proteins, including the C4 binding protein, factor H, complement receptor type 1, complement receptor type 2, Ba, C1r, and to their non-complement relatives, including beta 2-glycoprotein I, factor XIIIb, the alpha 1 chain of haptoglobin, and the interleukin 2 receptor. Identifying DAF as a member of the superfamily of structurally related complement proteins provides evidence that DAF may contain a functionally important C4b and C3b binding domain.

Amino Acid Sequence↗
PubMed1984

Serum haptoglobin and alpha 1-acid glycoprotein as indicators of the effectiveness of cis-diamminedichloroplatinum (CDDP) in ovarian cancer patients--a preliminary report.

Twenty-one patients with adenocarcinoma of the ovary were given a maximum of five courses of CDDP by i.v. infusion every 4 weeks. With one exception, the serum levels of both haptoglobin and alpha 1-acid glycoprotein correlate with tumour burden before therapy and at follow-up. It is suggested that a more accurate assessment of the effectiveness of CDDP therapy may be obtained by estimating these serum proteins before each infusion than by an abdominal examination.

Adenocarcinoma↗