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Chemiluminescent image detection of haptoglobin phenotyping after polyacrylamide gel electrophoresis.

The development of an enhanced chemiluminescence detection method for the rapid detection of haptoglobin phenotyping after polyacrylamide gel electrophoresis is described in this paper. The enhanced chemiluminescence detection is based upon chemiluminescent reaction between luminol and hydrogen peroxide. Increased sensitivity and dynamic range are achieved by employing ammonium persulfate to enhance the chemiluminescence signal. Detection of haptoglobin phenotypes in human blood serum was easily achieved even without the addition of hemoglobin. Different polyacrylamide gel electrophoresis results were found between pure serum and hemoglobin-supplemented serum. Applying the suggested enhanced chemiluminescence detection, the original combining forms of haptoglobin and hemoglobin can be detected. The linear range of haptoglobin is 0.1-13.3 microg/mL, with a detection limit of 1.21 ng (sample loading volume 15 microL). Other proteins, such as catalase and ferritin, can also be detected using enhanced chemiluminescence detection. All detections after polyacrylamide gel electrophoresis were completed within 15 min. The proposed detection is very fast, compared to traditional methods using staining detection (minutes versus hours).

Ammonium Sulfate↗

Elevated levels of abnormally-fucosylated haptoglobins in cancer sera.

Cancer sera have higher levels of serum protein-bound fucose than sera from healthy individuals. In an attempt to identify the cause of this increase, fucoproteins were extracted from the sera of cancer patients and healthy individuals using a fucose-specific lectin (lotus tetragonolobus) coupled to Sepharose, and were analysed by polyacrylamide gel electrophoresis and silver staining. Of the several consistent changes observed for the cancer sera, the most striking was a large increase in a component of 40-45 Kdaltons. The expression of this component in the cancer sera was related to the elevation in serum fucose levels. Two dimensional (2D) electrophoretic analysis of lectin extracts showed that this component had a similar isoelectric point to the beta chains of haptoglobin. Its identity as haptoglobin was confirmed using Western blotting and an anti-haptoglobin antibody. Fucosylated haptoglobins (FHp) were also isolated from some rheumatoid arthritis sera, but there was no correlation between serum fucose levels and the FHp expression. The FHp in cancer sera was of higher molecular weight than that found in rheumatoid sera. Serial specimens from two ovarian cancer patients undergoing chemotherapy had elevated FHp associated with increased amounts of tumour. To the best of our knowledge this is the first time a molecule of this type has been reported in cancer sera and because of its uniqueness it deserves further investigation as a potential cancer marker.

Adolescent↗

Pig MAP/ITIH4 and haptoglobin are interleukin-6-dependent acute-phase plasma proteins in porcine primary cultured hepatocytes.

The acute-phase expression of pig MAP (major acute-phase protein)/ITIH4 (inter-alpha-trypsin inhibitor heavy chain 4) and haptoglobin were analysed in primary cultures of isolated pig hepatocytes in response to recombinant human (rh) cytokines: tumor necrosis factor-alpha (TNF-alpha), interleukin-1 (IL-1), interleukin-6 (IL-6), as well as to bacterial lipopolysaccharide (LPS). Analysis of pig MAP/ITIH4 and haptoglobin mRNAs was carried out by RT-PCR amplification. Secreted proteins from the cytokine-treated hepatocytes were quantified by immunochemical techniques. Time-course and dose-response experiments show that pig MAP/ITIH4 and haptoglobin belong to the type II acute-phase proteins, as they are specifically induced by rhIL-6 and not by rhTNF-alpha or rhIL-1. Stimulation of cultured pig hepatocytes with rhIL-6 for 48 h at doses of 1000 U.mL-1 showed a fourfold to fivefold increase in pig MAP/ITIH4 concentration in the medium, while the concentration of haptoglobin only increased twofold. A similar increase in the concentration of pig MAP/ITIH4 was also observed in media of LPS-treated hepatocytes with the simultaneous generation of IL-6 by the Kupffer cells present in the cultures. Albumin secretion decreased after stimulation with doses of 100 or 1000 U.mL-1 rhTNF-alpha, rhIL-1 or rhIL-6. Therefore, it can be concluded that pig MAP/ITIH4 behaves as a major acute-phase protein produced by porcine hepatocytes under the effect of inflammatory cytokines.

Acute-Phase Proteins↗

Plasma haptoglobin concentration in swine after challenge with Streptococcus suis.

Eight 15-week-old pigs, reared under specific pathogen-free conditions, were inoculated with Streptococcus suis serotype 2. The animals were monitored before and after challenge by measuring rectal temperature, recording specific clinical symptoms and collecting blood samples for haptoglobin determination. Twenty-four hours after infection, the average haptoglobin plasma concentration of the animal group increased significantly and reached a maximum 4 days post-inoculation, followed by a constant mean level until the end of the trial on day 10. In spite of individual differences between the animals, an increase in haptoglobin concentration of at least 2.5 times above normal was observed in all infected pigs 1 day after challenge. Twenty-four hours after challenge, lameness was observed in five animals and an elevated body temperature was observed in seven of the eight experimental infected animals. These are the classical clinical symptoms of streptococcal infection. Haptoglobin was shown to increase in acute S. suis infection in pigs.

Animals↗

Development of a time-resolved fluorometry based immunoassay for the determination of canine haptoglobin in various body fluids.

A time-resolved immunofluorometric assay (TR-IFMA) was developed for the determination of haptoglobin (Hp) in canine serum. Haptoglobin was purified from canine acute phase serum by ammonium sulphate precipitation followed by gel filtration. This isolated dog Hp was used as the standard to calibrate the assay. Intra- and inter-assay coefficients of variation of the assay were, respectively, 5.7% and 16.6% at 0.51 mg/mL, 2.4% and 10.6% at 2.1 mg/mL and 10.5% and 11.9% at 32.5 mg/mL. The dilution of serum samples with high Hp concentrations resulted in linear regression equations with R2 of 0.99 and 0.97. A high correlation was found in serum Hp measurements by TR-IFMA and a commercial assay based on peroxidase activity of haemoglobin bound to haptoglobin (R2 = 0.96). The limit of detection for the TR-IFMA method was 0.002 microg/mL. The addition of fresh haemolysate to serum samples did not affect the haptoglobin concentration (P = 0.694). Statistical differences (P < 0.003) were found between healthy dogs and dogs with different pathological processes. In whole blood, Hp concentrations were much lower than in serum but closely related (R2 = 0.84) whereas saliva Hp concentrations were poorly related with serum concentrations (R2 = 0.53). However, the concentration of Hp in saliva was significantly (P < 0.039) higher in dogs with pathological processes compared to healthy dogs. The assay sensitivity was adequate to also be applied to whole blood and saliva specimens.

Animals↗

Model for haptoglobin heavy chain based upon structural homology.

A model has been constructed for haptoglobin heavy chain by using the known sequence homology to the mammalian serine proteases. The three-dimensional structures for three serine proteases, chymotrypsin, trypsin, and elastase, were compared and the structural features that are conserved in all three were extracted. The haptoglobin heavy chain sequence was aligned to the sequences of the three serine proteases by maximizing sequence homology in the regions of conserved structure. The resulting alignment shows that haptoglobin heavy chain must be very closely homologous to these proteases in structure as well as in sequence. Coordinates were derived for the heavy chain by using the homologous structures. The problems associated with these coordinates are outlined and methods for solving them are indicated. The features of the haptoglobin heavy chain structure are described. Implications of the structure for the very strong interaction between this subunit and hemoglobin are discussed.

Amino Acid Sequence↗

A glycomic approach to hepatic tumors in N-acetylglucosaminyltransferase III (GnT-III) transgenic mice induced by diethylnitrosamine (DEN): identification of haptoglobin as a target molecule of GnT-III.

A glycomic approach to the identification of target molecules in glycosyltransferase gene targeting mice is a promising strategy to understand the biological significance of glycosyltransferase genes in vivo. In order to understand the biological effects of N-acetylglucosaminyltransferase III (GnT-III) on tumor formation in the liver, diethylnitrosamine (DEN) induced tumor formation in the GnT-III transgenic mice was examined. Our findings show that the incidence of hepatic tumor could be dramatically suppressed. A glycomic approach using two-dimensional gel electrophoresis followed by lectin blot analysis and sequence analysis revealed that haptoglobin, a radical scavenger molecule in serum was heavily glycosylated in hepatic tumor-bearing GnT-III transgenic mice that had been treated with DEN. Immunoprecipitation followed by E4-PHA lectin blot analysis also confirmed that the bisecting GlcNAc, a product of GnT-III was added to haptoglobin molecules. Since the use of DEN is known to lead to the production of lipid peroxidation products which facilitate this reaction and haptoglobin is an acute phase reactant, acting as a radical scavenger against hemoglobin or iron stimulated lipid peroxidation, a relationship between the glycosylation of haptoglobin and the suppression of hepatoma development can not be ruled out. This paper is the first report that shows a relationship between the sugar chains of glycoproteins with radical scavenger activity and hepatocarcinogenesis.

Animals↗

Haptoglobin-haemoglobin complex in human plasma inhibits endothelium dependent relaxation: evidence that endothelium derived relaxing factor acts as a local autocoid.

Endothelium dependent relaxation of isometrically mounted rabbit aortic strip preparations was rapidly inhibited by human plasma at dilutions down to 1:1000. Gel filtration and ion exchange chromatography were used to demonstrate that this inhibitory activity was present in fractions containing haptoglobin. Purified haptoglobin itself possessed no inhibitory action against endothelium dependent relaxation, but the haptoglobin-haemoglobin complex did, consistent with the documented ability of haemoglobin to inhibit this phenomenon. The concentration of haemoglobin normally bound to haptoglobin is sufficient to account for the inhibitory properties of human plasma. This suggests that endothelium derived relaxing factor exerts no downstream intravascular effect in vivo and thus that its physiological dilator role is that of a local autocoid acting on subjacent smooth muscle.

Animals↗

Peritoneal endometriotic lesions differentially express a haptoglobin-like gene.

A unique glycoprotein, called endometriosis protein-I (ENDO-I), has previously been shown to be synthesized and secreted by rat and human endometriotic explants. Furthermore, the N-terminal amino acid sequence analysis showed that ENDO-I shares homology with haptoglobin. The present study was designed to determine this sequence of ENDO-I cDNA from human peritoneal endometriotic lesions and to determine the relative expression of the ENDO-I gene in several human tissues. Poly A-enriched RNA was isolated and reverse-transcribed. To determine the sequence of ENDO-I cDNA, a polymerase chain reaction was performed on cDNA from human endometriotic lesions and a gene-specific primer based on the human haptoglobin sequence. A similar procedure was followed to assess the relative expression of the ENDO-I gene in various tissues. Glyceraldehyde-3-phosphate-dehydrogenase was used as an internal control. ENDO-I gene expression was quantified by densitometry. Sequence analysis of ENDO-I cDNA identified 873 nucleotides that displayed 99.4% homology with the human haptoglobin beta-chain. Relative expression of ENDO-I mRNA by peritoneal endometriotic lesions was 19-fold greater than peritoneum, 28-fold greater than endometrioma and 37-fold greater than eutopic endometrium (P<0.01). Haptoglobin-like ENDO-I may be associated with localized angiogenesis and altered immune response involved with the aetiology/pathophysiology of endometriosis.

Adolescent↗

Heart rate variability is associated with haptoglobin phenotype in patients with coronary artery disease.

BACKGROUND: Three haptoglobin phenotypes exist called Hp 1-1, Hp 2-2, and Hp 2-1. Patients carrying the haptoglobin 1 allele seem to be partly protected against coronary artery disease. An attenuated heart rate variability is associated with a poor outcome in patients with coronary artery disease. Therefore, we hypothesized that the presence of the haptoglobin 1 allele would be associated with a favourable heart rate variability. DESIGN: A cross-sectional study. METHODS: We included 255 patients who were referred for elective coronary angiography as a result of suspected coronary artery disease, and all underwent 24-h electrocardiogram recordings to assess heart rate variability in the time domain. The haptoglobin phenotype was also determined in each patient. RESULTS: There were 159 patients in the Hp 1-1 and Hp 2-1 groups and 98 patients in the Hp 2-2 group. The two groups were comparable with respect to clinical parameters. However, the Hp 2-2 group had significantly lower 24-h heart rate variability values compared with the other group (RR 882 versus 921 ms, P=0.02; RMSSD 26 versus 30 ms, P<0.01; pNN50 6 versus 9%, P=0.01). Furthermore, Hp 2-2 was independently and negatively associated with heart rate variability (P=0.02). CONCLUSION: Hp 2-2 was associated with an attenuated heart rate variability in patients with coronary artery disease that may help to explain other results reporting a poor prognosis in Hp 2-2 patients.

Aged↗

Haptoglobin therapy for acute favism: a Japanese boy with glucose-6-phosphate dehydrogenase Guadalajara.

We report the case of a 2-year-old Japanese boy with acute favism who was treated with human haptoglobin products. He had been exhibiting chronic nonspherocytic haemolytic anaemia until the diagnosis of glucose-6-phosphate dehydrogenase (G6PD) deficiency when 14 months old. He suffered a favic crisis at 24 months of age, when the administration of haptoglobin was effective for relieving bilirubinaemia and haemoglobinuria. Serum-free Hb rapidly decreased to normal levels despite the sustained level of serum lactate dehydrogenase. His G6PD gene was G6PD Guadalajara. This is the first application of haptoglobin therapy for acute favism and the first reported case of Japanese G6PD deficiency with typical favic crisis. Haptoglobin treatment might be helpful for managing the haemolytic crisis in the disease.

Child, Preschool↗

Decreased haptoglobin levels in respiratory allergy.

As unusually high frequency of decreased haptoglobin levels in patients with asthma and/or rhinitis is described. The condition is significantly associated with haptoglobin 2-2 phenotype. Decreased haptoglobin levels are more frequently associated with young age, atopic antecedents, positive skin tests for pollens, higher IgE and higher RAST activity for pollens and housedust mite. Whether the association of decreased haptoglobin levels and IgE-mediated respiratory disease has a physiopathological significance or is solely the expression of a common genetic determinate remains to be investigated.

Adolescent↗

Localization of haptoglobin in normal human skin and some skin diseases.

BACKGROUND: Haptoglobin (Hp) is an acute-phase reactant, known to be produced mainly in the liver. Haptoglobin can also be detected in the cytoplasm of normal epidermal Langerhans cells (LCs), and can prevent their functional maturation. The synthesis of Hp in skin cells has not been well studied. METHODS: We examined Hp expression at mRNA and protein levels by in situ hybridization and immunohistochemistry, respectively, in normal human skin and in the skin of patients with psoriasis, lichen planus, erythroderma, seborrheic keratosis, verruca vulgaris, basal cell carcinoma, systemic lupus erythematosus, pemphigus and bullous pemphigoid. RESULTS: (1) Haptoglobin mRNA was expressed in the epidermal keratinocytes (KCs), the epithelial cells of hair follicles, sebaceous glands and eccrine glands in normal skin and all dermatoses investigated. (2) Whereas compared with normal skin, the Hp mRNA in KCs of patients with psoriasis, lichen planus, erythroderma, seborrhoea keratosis and verruca vulgaris was significantly intensified, it was weaker in patients with systemic lupus erythematosus, pemphigus and bullous pemphigoid. (3) Haptoglobin protein only stained positively in some KCs of patients with psoriasis, lichen planus and erythroderma. (4) Although some but not all epidermal LCs were positively stained with anti-Hp antibody in normal skin and in skin samples from all patients, the ratios of Hp-positive LCs/total LCs were significantly higher in those diseases with intensified Hp mRNA in KCs. CONCLUSIONS: Skin is another extrahepatic organ where Hp can be synthesized by KCs. The expression of Hp mRNA in KCs and the Hp protein in both LCs and KCs appears to be correlated with the amount of inflammation, which might indicate that skin itself is involved in down-regulating the local inflammatory reaction by KC-synthesized Hp.

Haptoglobins↗

Globin-chain affinity chromatography on Sepharose-haptoglobin: a new method of study of hemoglobin synthesis in reticulocytes, in bone marrow and in colonies of erythroid precursors.

In the present work we have developed an affinity chromatography system, using haptoglobin bound covalently to Sepharose 4B, to purify hemoglobin from soluble non-heme proteins. Sepharose-haptoglobin specifically binds hemoglobin. It exhibits the same characteristics in its interactions with hemoglobin and alpha or beta hemoglobin chains as does haptoglobin in solution. Globin chains can be eluted from the Sepharose-haptoglobin after removal of the heme. This method has allowed accurate measurements of globin-chain synthesis in blood and bone marrow samples and in culture of early erythroid precursors.

Adult↗

Structural analysis of the asparagine-linked oligosaccharides of rat haptoglobin metabolically labeled in a hepatocyte culture system.

We analyzed the asparagine-linked oligosaccharide chains of rat haptoglobin which were synthesized and secreted by hepatocytes in primary culture. When the cells were incubated with either [3H]mannose, [3H]galactose, or [3H]fucose, all the radioactive precursors were incorporated into the beta subunit of haptoglobin. [3H]Mannose-labeled haptoglobin was purified from the culture medium by immunoaffinity chromatography, and [3H]oligosaccharides were prepared by strong alkali-borohydride treatment. The oligosaccharides obtained were analyzed by anion-exchange high-performance liquid chromatography, concanavalin-A--Sepharose chromatography and Bio-Gel P-4 chromatography before and after sequential exoglycosidase digestions. The oligosaccharides labeled with [3H]fucose or [3H]galactose were also characterized by the above methods. The results indicate that rat haptoglobin contains two complex-type oligosaccharide chains in each beta subunit; one with a possible structure of ( +/- NeuAc----Gal beta----GlcNAc beta----)3(Man alpha----)2 Man beta----GlcNAc----( +/- Fuc alpha----)GlcNAc and the other with ( +/- NeuAc----Gal beta----GlcNAc beta----Man alpha----)2 Man beta----GlcNAc----( +/- Fuc alpha----)GlcNAc.

Animals↗

The clinical significance of the serum haptoglobin concentration in patients with invasive cervical carcinoma.

The serum haptoglobin concentration was measured by rate nephalometry in 56 patients with invasive carcinoma of the cervix, and in 24 women with no evidence of cervical pathology who served as control subjects. There was a significant difference in the mean serum haptoglobin concentration (p less than 0.005) between the 2 groups of patients. However there was no significant correlation between the serum haptoglobin concentration and the clinical stage of the disease. From our data we propose that a serum haptoglobin concentration greater than 96 mg/dl is suggestive of invasive carcinoma of the cervix, and that this may be used as additional investigation in the initial assessment of such patients.

Carcinoma↗

Identification of an outer membrane protein involved in utilization of hemoglobin-haptoglobin complexes by nontypeable Haemophilus influenzae.

A recombinant plasmid containing a 6.5-kb fragment of nontypeable Haemophilus influenzae (NTHI) chromosomal DNA was shown to confer a hemoglobin-haptoglobin-binding phenotype on Escherichia coli. Use of a mini-Tn10kan transposon for random insertion mutagenesis of this recombinant plasmid allowed localization of the NTHI DNA responsible for this hemoglobin-haptoglobin-binding phenotype to a 3.5-kb PstI-XhoI fragment within the 6.5-kb NTHI DNA insert. When this mutagenized NTHI DNA fragment was used to transform the wild-type NTHI strain, the resultant kanamycin-resistant mutant exhibited significantly decreased abilities to bind hemoglobin-haptoglobin and utilize it as a source of heme for aerobic growth in vitro. This mutant also lacked expression of a 115-kDa outer membrane protein that was present in the wild-type parent strain. Transformation of this mutant with wild-type NTHI chromosomal DNA restored the abilities to bind and utilize hemoglobin-haptoglobin and to express the 115-kDa outer membrane protein. Nucleotide sequence analysis of the relevant NTHI DNA revealed the presence of a gene, designated hhuA, that encoded a predicted 117,145-Da protein. The HhuA protein exhibited features typical of a TonB-dependent outer membrane receptor and had significant identity with the hemoglobin receptors of both Haemophilus ducreyi and Neisseria meningitidis.

Amino Acid Sequence↗

Serum haptoglobin concentration as a marker of clinical signs in finishing pigs.

A case-control study of 340 finishing pigs aged 10 to 25 weeks in 15 commercial Danish pig herds was carried out to investigate serum haptoglobin concentration as an objective marker of clinical signs of disease. Pigs with different clinical signs were matched to control pigs without clinical signs with respect to herd, pen, estimated weight and gender, and each pig was subjected to a standard clinical examination. In 86 of the case-control pairs, the rectal temperature was also recorded. There was a significantly higher mean haptoglobin concentration in the serum of lame pigs (P<0.0001), pigs with respiratory disease (P=0.0004), pigs with tail or ear bites (P=0.0004) and pigs with diarrhoea (P=0.02). Similarly, a higher mean rectal temperature was recorded in lame pigs (P<0.0001), pigs with respiratory disease (P=0.002) and pigs with tail or ear bites (P=0.0003). There was a significant but low correlation between rectal temperature and haptoglobin concentration in serum (P=0.003, r=0.20). The area under the receiver-operating-characteristic curve was between 0.67 and 0.78 for the different clinical signs. The maximum simultaneous levels of sensitivity (0.61 to 0.71) and specificity (0.61 to 0.77) of serum haptoglobin for the different clinical signs were obtained at a cut-off value of 1.1 mg/ml. At a cut-off value of 1.8 mg/ml, the sensitivity decreased to 0.31 to 0.60, and the specificity increased to 0.82 to 0.86. It was not possible to define a cut-off value which classified individual pigs according to their clinical signs.

Animals↗