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A Lundblad

Publications and source records attributed to A Lundblad.

At least 37 records · Page 2Linked to original sources
PubMed1996

E-selectin: sialyl Lewis, a dependent adhesion of colon cancer cells, is inhibited differently by antibodies against E-selectin ligands.

Recent studies have demonstrated that selectins, a new family of cell-adhesion molecules with similar domain structures, mediate the adhesion of peripheral blood cells to interleukin-1 (IL-1)-activated endothelium. In the present study the authors evaluated the role of E-selectin-Sialyl Lewis x (SLe(x))/ Sialyl Lewis a (SLe(a)) interaction in mediating in vitro adhesion of two colon cancer cell lines, HT-29 and COLO 201, to human umbilical cord endothelial cells (HUVEC). Colon cancer cell lines had a strong expression of blood group-related carbohydrate epitopes as evaluated by fluorescence-activated cell sorter (FACS) analysis. It was established that adhesion of HT-29 and COLO 201 cells to IL-1 stimulated HUVEC was calcium dependent and could be inhibited by a monoclonal antibody directed against E-selectin. Prior incubation of cells with two different antibodies directed against SLe(x) and antibodies directed against related Lewis epitopes, Le(x) and Le(a), had no significant effect on adhesion. Three antibodies directed against SLe(a) differed in their capacity to inhibit the adhesion of HT-29 and COLO 201 cells to HUVEC. Only one antibody directed against the SLe(a) structure was effective in inhibiting adhesion of both COLO 201 and HT-29 cells. The difference could not be attributed to titre, the type or number of glycoproteins, or to a difference in the amount of SLe(a) present on individual proteins, suggesting that presence and right presentation of SLe(a) epitope might be important for adhesion of colon cancer cells. Finally, in the in vitro system used, adhesion of HT-29 and COLO 201 cells to activated HUVEC is mediated predominantly by E-selectin/SLe(a) interaction. SLe(x) and related epitopes, Le(x) and Le(a), seem to have limited relevance for colon cancer cell recognition of E-selectin.

Antibodies, Monoclonal↗
PubMed1996

Association between serum sialic acid concentration and carotid atherosclerosis measured by B-mode ultrasound. The ARIC Investigators. Atherosclerosis Risk in Communities Study.

BACKGROUND: Previous studies have shown that the serum level of sialic acid is associated positively with mortality from coronary disease and stroke. In this study its relation with carotid atherosclerosis was evaluated. METHODS: From the Atherosclerosis Risk in Communities (ARIC) Study, 323 cases with carotid intima-media wall thickness above the 90th percentile (measured with B-mode ultrasound) were matched 1:1 with controls without atherosclerosis. Serum sialic acid, plasma LDL and HDL cholesterol, serum insulin concentrations, blood pressure, antihypertensive medication use, and smoking status were used to assess the independent contribution of the sialic acid level to carotid atherosclerosis. RESULTS: The mean (SD) serum sialic acid concentration was 75.0 (9.7) mg/dl in cases and 70.7 (8.9) mg/dl in controls (P = 0.0001). In a conditional logistic model with adjustment for age, LDL-cholesterol, HDL-cholesterol, serum insulin, smoking and hypertension, the odds ratio associated with sialic acid above the 75th percentile (> or = 78.3 mg/dl) versus below was 1.65 with a 95% confidence interval of 1.01-2.70. CONCLUSION: The sialic acid level is correlated with the presence of carotid atherosclerosis, independently of major cardiovascular disease risk factors. The biological mechanism behind this association is not resolved.

Arteriosclerosis↗
PubMed1995

Carbohydrate composition of serum transferrin isoforms from patients with high alcohol consumption.

Normal human serum transferrin is present in several isoforms, due to differences in glycosylation. Transferrin has two potential glycosylation sites, both normally occupied by oligosaccharide chains. Two of the transferrin isoforms, called carbohydrate deficient transferrin, are specifically increased in patients with high alcohol consumption. In this study, five isoforms of transferrin were isolated from patients with high alcohol consumption. N-linked glycans were released by N-glycosidase digestion and were radioactively labeled by NaB3H4 reduction. The purified oligosaccharides were analyzed by high-pH anion-exchange chromatography, and the carbohydrate composition of each individual transferrin isoform was determined. The carbohydrate deficient transferrin isoforms were found to lack one or both of their entire carbohydrate chains.

Alcohol Drinking↗
PubMed1995

Role of N-linked glycosylation in expression of E-selectin on human endothelial cells.

E-selectin is a cytokine-inducible membrane glycoprotein capable of mediating adhesion of leukocytes to endothelial cells. It is highly glycosylated, containing 11 sites for N-linked glycosylation. N-Glycosylation of E-selectin was analyzed by endoglycosidase treatment. Analysis of immunoprecipitated E-selectin from human umbilical vein endothelial cells (HUVEC) by polyacrylamide gel electrophoresis in the presence of sodium dodecylsulfate showed that E-selectin was completely resistant to endoglycosidase H, but sensitive to peptide N-glycanase F digestion. This suggested that all N-linked oligosaccharide chains were of the complex type. The role of N-linked glycosylation in surface expression and secretion of E-selectin was studied using interleukin-1-stimulated HUVEC, cultured in the presence of the soluble glycosylation inhibitors tunicamycin or castanospermine. Cell surface expression was analyzed by indirect flow cytometry. N-Glycosylation was blocked by tunicamycin, and resulted in a significantly reduced surface expression of E-selectin, whereas castanospermine only marginally reduced E-selectin expression. The deglycosylated forms of E-selectin were also found to be fully capable of mediating adhesion of HT-29 cells in vitro. In conclusion, these studies show that E-selectin is heavily glycosylated with complex type N-linked oligosaccharides and that N-glycosylation is important for expression of E-selectin on human endothelial cells.

Cell Adhesion↗
PubMed1993

Serum concentrations of total sialic acid and sialoglycoproteins in relation to coronary heart disease risk markers.

This study investigated the relationship between serum sialic acid concentration and cardiovascular mortality. Correlations were determined between lifestyle-related coronary heart disease risk markers (cigarette consumption, alcohol consumption, and leisure time physical activity), biological risk markers (apolipoprotein A1, apolipoprotein B, lipoprotein(a), and diastolic blood pressure) on the one hand and the concentration of sialic acid as well as sialic acid-rich acute phase proteins (orosomucoid, haptoglobin, and alpha 1-antitrypsin) on the other. A total of 145 men aged 21-46 years and with a C-reactive protein concentration below 5 mg/l were included. Total sialic acid concentration correlated significantly with apolipoprotein B (r = 0.48), number of cigarettes smoked daily (r = 0.32), and leisure time physical activity (r = -0.23) after adjustment for age and other cardiovascular risk markers. No significant partial correlations were found between serum total sialic acid concentration on the one hand and alcohol consumption, apolipoprotein A1, lipoprotein(a), and diastolic blood pressure on the other. Of the sialic acid-rich glycoproteins, orosomucoid correlated with apolipoprotein B (r = 0.38), haptoglobin with cigarette consumption (r = 0.35) and leisure time physical activity (r = -0.26) and alpha 1-antitrypsin with cigarette consumption (r = 0.18), leisure time physical activity (r = 0.17), alcohol consumption (r = -0.18), and apolipoprotein B (r = 0.21) after adjustment for age and other cardiovascular risk markers.

Acute-Phase Proteins↗
PubMed1993

E-selectin involvement in in vitro adhesion of blood dendritic cells to human umbilical cord endothelial cells.

Peripheral blood dendritic cells (BDC) are potent antigen-presenting lymphoid cells. In the present study, we have examined the in vitro adhesion of BDC to human umbilical cord venous endothelial cells (HUVEC) and studied the expression of CD molecules and oligosaccharide haptens on BDC and endothelial cells. Immunohistochemistry showed that BDC were strongly positive for antibodies against HLA-DR, CD11c, CD18, CD44 and CD54, and moderately positive for anti-CD11a, CD31, CD43 and CD58. In addition, BDC were moderately positive for anti-Sialyl Lewis a and strongly positive for anti-Sialyl Lewis x and CD77 (Gal alpha 1-4Gal beta 1-4Glc) Non-stimulated HUVEC were positive for anti-CD29, CD31 and CD77. An in vitro adhesion assay showed that only a small percentage of radiolabelled BDC bound to non-stimulated HUVEC (16.9 +/- 5.9%, mean +/- SD). Stimulation of the HUVEC with IL-1 for 4 h produced a significant increase (P < 0.002) in the percentage of radiolabelled BDC that bound to HUVEC (42.3 +/- 7.1%). Preincubation of HUVEC with antibodies against E-selectin (10 micrograms/ml) significantly inhibited (P < 0.02) the binding of radiolabelled BDC to activated HUVEC (32.2 +/- 1.3%) whereas preincubation of BDC with antibodies against CD54, CD18, CD11b, CD11c and Sialyl Lewis x did not produce any significant inhibition. Preincubation of BDC with Sialyl Lewis a antibody and with isotype-matched control antibodies did not affect the increased binding of BDC to IL-1-activated HUVEC. Thus, E-selectin seems to be involved in adhesion of BDC to IL-1-stimulated HUVEC.

Cell Adhesion↗
PubMed1992

Assay of alpha 1,3 N-acetyl-D-galactosaminyl transferase by affinity chromatography.

A high-performance liquid affinity chromatography column that contains immobilized anti-A monoclonal antibody specifically retards blood group A-active oligosaccharides and can be used to detect the product(s) of the reaction catalyzed by alpha-1,3-N-acetyl-D-galactosaminyltransferase: [formula: see text] After a brief incubation (15 min) of an assay mixture containing 1-100 microliters human serum, the sugar nucleotide donor UDP-GalNAc, and radiolabeled oligosaccharide acceptors 2'-fucosyllactose and/or lacto-N-fucpentaose I blood group A-active products are isolated and quantitated in a single affinity chromatographic step that takes less than 30 min. Kinetic studies to determine the pH optima for serum alpha-3-GalNAc transferase from individuals of blood groups A1 and A2 and the Km value for UDP-GalNAc for the A1 transferase agree with previous determinations. As monoclonal antibodies against many different complex carbohydrate antigens are now available, the method described could be adapted to give rapid, inexpensive assays for a variety of glycosyltransferases.

Carbohydrate Sequence↗
PubMed1991

Affinity purification of monoclonal antibodies, using a bifunctional oligosaccharide hapten.

A bifunctional hapten was synthesized consisting of a blood group A active tetrasaccharide (A-tetra) and a blood group Le(a) active pentasaccharide lacto-N-fucopentaose II (LNF II), linked to each other with a phenylaminothiourea spacer connecting the reducing ends (A-tetra-LNF II). The hapten was demonstrated to retain both blood group A and Le(a) activity and could be easily bound to both monoclonal anti-A and anti-Le(a) affinity columns. Due to the strong temperature dependence of the two antibodies their binding to oligosaccharides, the bifunctional hapten could be utilized to achieve easy desorption in the final step of affinity purification of either monoclonal anti-Le(a) or anti-A. The system is postulated to have general applicability in affinity purification of any ligate that binds with an avidity too high to achieve non-denaturing desorption.

Antibodies, Monoclonal↗
PubMed1991

Affinity chromatographic identification and quantitation of blood group A-active oligosaccharides in human milk and feces of breast-fed infants.

The finding of large quantities of blood group A-active oligosaccharides in the feces of a blood group A breast-fed infant motivated a search for the origin of these compounds. Using an affinity chromatographic technique, the nature of A-active oligosaccharides in human milk is demonstrated. The amounts of A-active tetrasaccharide (A-tetra) and the Lewis b-active lacto-N-difucohexaose I (LND-I) varied between 19-375 mg/L for A-tetra and 14-710 mg/L for LND-I. Using the same technique, the amounts of A-tetra and LND-I in milk samples from five women of different blood groups were compared with those in the feces of their breast-fed infants. The A-tetra was present only in feces from infants of blood group A or AB mothers and the amount per 24 h corresponded roughly to that in a I-L portion of milk. One of the milk samples was also analyzed for the presence of larger A-active oligosaccharides (A-pentasaccharide, A-hexasaccharide, and A-heptasaccharide). Their amounts were much less as compared to the amounts present in feces. These results indicate that milk is a possible source for the smallest A-tetrasaccharide found in the feces of breast-fed infants, while the larger A-active oligosaccharides might be the result of an intestinal metabolic modification.

ABO Blood-Group System↗
PubMed1991

Sialylated oligosaccharides in human milk and feces of preterm, full-term, and weaning infants.

The amount of free and glycosidically bound sialic acid was quantitated in the oligosaccharide fraction of breast milk from nine women in the 2nd-3rd week of lactation. These amounts showed a certain individual variation but the amount of bound sialic acid was higher than the free sialic acid in each sample. A similar study on the feces from preterm and full-term breast-fed infants revealed that the amount of free sialic acid increased while the bound sialic acid decreased during maturation, which could possibly be a result of increasing activity of an intestinal sialidase in the newborn child. The fecal oligosaccharide patterns in one blood group A secretor breast-fed infant were studied every 2 months during weaning until the age of 1 year. It was seen that the fecal oligosaccharide pattern disappears, along with the blood group A-active compounds, with a corresponding decrease in the amount of breast milk in the diet.

Breast Feeding↗
PubMed1990

Sialyllacto-N-fucopentaose II (sialylated Le(a)) coupled to humanserum albumin used as standard in immunoassays of tumour associated antigens CA 19-9 and CA-50 in serum.

Penta and hexasaccharides from human milk, containing sialic acid and/or fucose residues were conjugated to human serum albumin and used as antigens in three different methods for CA 19-9, two methods for CA-50 and one method for CA-195. In accordance with reported results, the 19-9, CC 3C 195 and C-50 monoclonal antibodies were found to react with the sialyllacto-N-fucopentaose II conjugate, although to a different extent. A negligible reaction was observed with the isomeric conjugate, sialyllacto-N-fucopentaose III, and no reaction was seen with the sialyllacto-N-tetraose conjugate. The use of defined oligosaccharide conjugates for the standardization of assays of tumour markers in serum is discussed.

Antigens, Tumor-Associated, Carbohydrate↗
PubMed1989

Determination of a glucose-containing tetrasaccharide in urine of patients with acute pancreatitis.

The oligosaccharide Glc alpha 1-6Glc alpha 1-4Glc alpha 1-4Glc (Glc4), formed by amylolytic degradation of starch and glycogen, is excreted at extremely high levels in the urine of patients with acute pancreatitis. To determine if Glc4 is a useful indicator for this disease, we studied 55 patients admitted to the hospital because of acute abdominal pain (possibly acute pancreatitis). The highest values of Glc4 excretion in urine was found in a group of 11 patients with acute pancreatitis. The Glc4 values, but not serum and urine amylase values obtained at admission, correlated significantly with the severity of the disease. In two patients, followed through convalescence, the Glc4 excretion remained elevated for 7 and 2 wk in contrast to serum and urine amylase that returned to normal levels within a few days. It seems probable that glycogen, released from the liver and subsequently degraded by amylase originating from the pancreas, can be measured as Glc4 in the urine. This might be valuable for diagnosing acute pancreatitis and gives indications of the prognosis.

Acute Disease↗
PubMed1989

Analysis of a glucose-containing tetrasaccharide by high-performance liquid affinity chromatography.

In the present work we have explored conditions for using a pulsed amperometric detector for on-line analysis of oligosaccharides eluted from a high-performance liquid affinity chromatography column. A monoclonal antibody that specifically binds a glucose-containing oligosaccharide is coupled to a SelectiSphere-10-activated tresyl column. The system is eluted isocratically and easily detects 10 ng of the oligosaccharide with a linear response up to 250 ng. Analysis of both serum and urine samples from normal individuals and patients with acute pancreatitis gives a single retarded peak with a retention time identical to that of authentic (Glc)4. Retarded material pooled from several analyses of urine was positively identified as (Glc)4 by GC-MS analysis. As this method requires little cleanup and no chemical derivitization of the sample and is performed rapidly (less than 20 min) at sensitivities of at least 10 micrograms/liter in biological fluids, it represents a substantial improvement over previous GC-MS, radioimmunoassay, and enzyme-linked immunoadsorbent assay methods used to determine (Glc)4.

Animals↗
PubMed1989

Structural and immunochemical analysis of three alpha-limit dextrin oligosaccharides.

Complete structures are described for three urinary oligodextrins from one patient with type II and one patient with type III glycogen storage disease. GLC-MS, direct probe MS, and 1H NMR demonstrate two heptasaccharides and one hexasaccharide containing only alpha 1-4 and alpha 1-6 linkages. The observation that all three oligosaccharides were present in urine of both patients and the occurrence of alpha 1-4 and alpha 1-6 linkages in characteristic sequences indicates that the oligodextrins are limit dextrins derived from alpha-amylolytic degradation of glycogen. The binding affinities of the oligodextrins for a monoclonal antibody (401/6) raised against Glc alpha 1-6Glc alpha 1-4Glc alpha 1-4Glc, were determined by frontal analysis. The highest affinity was exhibited by Glc alpha 1-6Glc alpha 1-4Glc alpha 1-4Glc followed by the two heptasaccharides and the hexasaccharide. The results from quantitative affinity measurements agree with results of structural analysis by physical methods in that all oligodextrins containing the nonreducing terminal sequence, Glc alpha 1-6Glc alpha 1-4Glc . . . , are specifically bound by the antibody with similar affinities, but the affinity is somewhat higher for chains containing the tetrasaccharide sequence Glc alpha 1-6Glc alpha 1-4Glc alpha 1-4Glc at the nonreducing terminal. Utilization of affinity methods offers clear advantages for isolation and characterization of oligosaccharides with very similar structures.

Antibodies, Monoclonal↗
PubMed1989

Enzyme immunoassay of beta-hexosaminidase isoenzymes using monoclonal antibodies.

Purified beta-hexosaminidase A (Hex A) and beta-hexosaminidase B (Hex B) were used as immunogens in mice, with the purpose of obtaining isoenzyme-specific monoclonal antibodies (mabs). A total of 60 mabs were developed, 23 specific for Hex A and 37 recognizing both isoenzymes. At low pH, two of the latter mabs reacted only with Hex B, and it was, therefore, possible to develop enzyme immunoassays for the specific determination of Hex A and Hex B. The precision of the methods was adequate with intra- and interassay coefficients of variation below 3%.

Animals↗
PubMed1988

Monoclonal antibodies produced by immunization with neoglycoproteins containing Gal alpha 1-4Gal beta 1-4Glc beta-O and Gal alpha 1-4Gal beta 1-4GlcNAc beta-O residues: useful immunochemical and cytochemical reagents for blood group P antigens and a differentiation marker in Burkitt lymphoma and other B-cell malignancies.

Several monoclonal antibodies (MAbs) directed to blood group P1 (Gal alpha 1-4Gal beta 1-4GlcNAc beta-O) and Pk (Gal alpha 1-4Gal beta 1-4Glc beta-O) determinants were produced with high efficiency by using synthetic neoglycoproteins as immunogens. The specificity of IgM and IgG1 MAbs was characterized by binding to defined oligosaccharides and glycoconjugates. Antibodies that bound equally well to P1 and Pk determinants and to Gal alpha 1-4Gal beta 1-O-derivatives were obtained, together with others that showed selective recognition of the entire trisaccharide chain. Selected antibodies were shown to be useful as reagents for detection of the blood group P antigens in glycolipid extracts of erythrocytes and on the surface of erythrocytes of different P phenotypes, demonstrated both by radioimmune assays and hemagglutination. Six IgM MAbs directed to the Pk determinant bound selectively to Burkitt lymphoma cells and 2 of these antibodies (424/3D9 and 424/6A2) could be used as auxiliary reagents in immunofluorescence for diagnosis and classification of B-cell lymphomas and leukemias using flow cytometric analysis. Eight normal individuals and 37 patients with lymphoma or leukemia were studied. Tumor cells of 2/2 patients with "Burkitt-like" lymphoma, 1 patient with centroblastic lymphoma and 2 patients with acute leukemia were strongly stained for the Pk antigen. The staining patterns for differentiation markers classified the tumor cells to a developmental stage closely related to the Burkitt cell type.

Animals↗
PubMed1988

Urinary excretion of a glucose-containing tetrasaccharide. A parameter for increased degradation of glycogen.

The urinary excretion of a glucose-containing oligosaccharide, Glc alpha[1-6Glc alpha[1-4Glc alpha[1-4Glc, (Glc4) has been measured in various physiological and pathological conditions. The Glc4 content of 24 h samples from the same individual was relatively constant, whereas 2 h samples showed up to 4-fold variations in Glc4 concentration. This variation is associated mainly with increased excretion of Glc4 after meals. A carbohydrate-rich diet, starvation or a protein-rich diet, and intense physical activity all affected the urinary excretion of Glc4. Both oral and intravenous administration of glycogen in a Rhesus monkey resulted in increased excretion of Glc4. When Glc4 itself was injected intravenously in small amounts renal clearance was rapid and complete. In contrast, injection of a larger amount resulted in incomplete (approximately 10%) renal clearance, probably due to uptake and metabolism of the oligosaccharide. In patients with glycogen storage diseases, certain malignancies, and pancreatitis, 24 h urinary Glc4 excretion exceeded the normal range. The diagnostic implications of these observations deserve evaluation. The results presented suggest a need for standardization of nutritional status and physical activity when monitoring urinary Glc4 excretion for diagnostic purposes.

Adult↗