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B Teisner

Publications and source records attributed to B Teisner.

At least 55 records · Page 3Linked to original sources
PubMed1994

Bovine conglutinin binds to an oligosaccharide determinant presented by iC3b, but not by C3, C3b or C3c.

Bovine conglutinin is a serum lectin that agglutinates erythrocytes preincubated with antibodies and complement. This agglutination occurs through the binding of conglutinin to iC3b, a fragment of the complement component C3. It was reported that conglutinin binds fluid-phase C3b and C3c as well as iC3b. We re-investigated the reactivity of conglutinin towards fluid-phase C3 degradation products. ELISA wells were coated with conglutinin and reacted with C3 split products generated in normal human serum, in factor I-deficient serum, or in factor I-depleted serum. Conglutinin-bound C3 fragments were detected with anti-C3c and anti-C3d antibodies. An increased signal was observed during the activation of complement in normal human serum with the peak response after 1-2 hr, following which the signal decreased, reaching background level after 72 hr. The oligosaccharides on C3c, generated in serum, are thus not recognized by conglutinin. No signal was observed when factor I-deficient serum or factor I-depleted serum was used instead of normal serum. Reconstitution with purified factor I re-established the normal pattern. Examination of the conglutinin-bound C3 molecules by SDS-PAGE and Western blotting with anti-C3c and anti-C3d antibodies revealed bands characteristic for iC3b, and no bands corresponding to C3b or C3c. Reduction of the disulphide bonds prior to the incubation of the activated serum with the conglutinin-coated wells revealed a band of 63,000 MW, characteristic of the N-terminal fragment of the alpha-chain of iC3b. We also investigated the binding to the solid-phase conglutinin of purified C3 and degradation products generated with enzymes. In this case, C3 as well as C3b and C3c were bound, suggesting conformational changes in C3 during purification. In conclusion, when C3 conversion takes place at near physiological conditions, conglutinin interacts specifically with the oligosaccharide on the alpha-chain of iC3b.

Animals↗
PubMed1993

Purification and characterization of a bovine serum lectin (CL-43) with structural homology to conglutinin and SP-D and carbohydrate specificity similar to mannan-binding protein.

A previously undescribed bovine serum lectin (designated CL-43) was identified by its Ca(2+)-dependent binding to mannan and by its molecular mass of 43 kDa under reducing conditions on SDS-PAGE. The lectin was isolated by polyethylene glycol precipitation, affinity chromatography on mannan-Sepharose (followed by elution with EDTA), and absorption on Sepharose-4B-coupled rabbit anti-bovine Ig (to remove anti-mannan antibodies). Fractions containing the lectin were reapplied to mannan-Sepharose. Bound conglutinin was eluted with GlcNAc, and then the 43-kDa lectin, together with mannan-binding protein (MBP), was eluted with mannose. The 43-kDa lectin was separated from MBP by ion exchange chromatography on Mono-Q. On SDS-PAGE under nonreducing conditions the lectin showed a molecular mass of 120 kDa. On gel chromatography under nondissociating conditions the protein was eluted at a volume corresponding to a molecular mass of approximately 750 kDa. Amino acid analysis showed the presence of hydroxyproline and hydroxylysine and a high content of glycine (24.3%) indicating the presence of a collagen-like structure. This was supported by the susceptibility of the protein to collagenase digestion. The designation CL-43 was chosen since this molecule appears to belong to the collectins, i.e. proteins with collagen structure and lectin activity. The N-terminal sequence (27 amino acids) showed 56% identity with bovine SP-D and 44% identity to bovine conglutinin. An inhibition assay with biotinylated CL-43, using solid-phase mannan as ligand, revealed the following carbohydrate inhibition pattern: mannose and ManNAc > fucose > GlcNAc > glucose and maltose > galactose > lactose >> GalNAc. We conclude that CL-43 is a circulating lectin, with structural similarities to bovine conglutinin and SP-D, and a ligand binding profile resembling that of MBP.

Amino Acid Sequence↗
PubMed1993

Serum PAPP-A levels are depressed in women with fetal Down syndrome in early pregnancy.

The value of maternal serum pregnancy-associated plasma protein (PAPP)-A in screening for Down syndrome in early pregnancy was assessed using stored samples. Seventeen cases of Down syndrome and 66 unaffected control pregnancies were studied. The median PAPP-A level in the cases was 0.42 multiples of the expected value in controls (p < 0.0001). Eleven cases (65 per cent) had levels less than half the expected value compared with only six controls (9 per cent). A commercial assay kit is now needed so that prospective screening with this marker can begin.

Biomarkers↗
PubMed1993

Serum PAPP-A measurements in first-trimester screening for Down syndrome.

Serum PAPP-A measurements taken from 254 women in the first trimester are reported. Eleven chromosomal abnormalities were detected. The mean serum PAPP-A levels in cases of Down syndrome were 0.44 MOM at 9 weeks gestation, 0.15 MOM at 10 weeks, and 0.29 MOM at 11 weeks. The PAPP-A level at 10 weeks was below those of pregnancies which aborted spontaneously. At 11 weeks, the pregnancies with Down syndrome recorded the lowest PAPP-A levels at that gestation. On this small sample, offering chorionic villus sampling to women with singleton pregnancies and a PAPP-A level below 0.3 MOM (approximately 6.5 per cent of this at-risk group) would have detected all the Down syndrome fetuses at 10 weeks and 50 per cent at 11 weeks without selecting those cases destined to abort. This suggests that serum PAPP-A should continue to be investigated as a potential first-trimester screening test for Down syndrome.

Adult↗
PubMed1993

Fetal antigen 1 (FA1) in the human pancreas: cell type expression, topological and quantitative variations during development.

Monospecific rabbit anti-human fetal antigen 1 (FA1), was used to examine the distribution of FA1 during the development of the human fetal pancreas and liver using an indirect immunoperoxidase technique. FA1 was expressed by 94% of the glandular epithelial cells of the branching ducts in the pancreatic anlage at week 7 of gestation. This pattern changed during the development of the human pancreas, 64% of the glandular cells being FA1 positive at week 17 of gestation, decreasing to 11% in the infant (4 months after birth). In the infant and adults the FA1 expression was restricted to a subpopulation of beta-cells within the islets of Langerhans. Insulin immunoreactive cells were scattered throughout the epithelium of primitive branching pancreatic ducts at week 7 of gestation, well before the formation of islets. From the 7th through to the 17th week of gestation, FA1 was found in the cytoplasm of fetal hepatocytes, whereas no staining was observed in the liver from a 4-month-old infant. No FA1 expression was found in the epithelium of the developing gut. The present findings indicate that the glandular epithelial cells in the developing pancreas may serve as stem cells, which, if appropriately induced, may differentiate into endocrine cells. Fetal antigen 1 (FA1) may take part in or be a result of this differentiation.

Adult↗
PubMed1993

Changes in blood levels of proteinase inhibitors, pregnancy zone protein, steroid carriers and complement factors induced by oral contraceptives.

Three low-dose oral contraceptives Trinordiol, Gynatrol, and Marvelon, containing ethinylestradiol (EE) in combination with triphasic levonorgestrel (LNg), monophasic levonorgestrel, and monophasic desogestrel (DGS), respectively, were given to 65 healthy women, n = 21-22 in each group. Blood levels of antithrombin III (AT III), alpha 2-macroglobulin (alpha 2M) alpha 1-antitrypsin (alpha 1at), complement factors (factor B, C3, C4), pregnancy zone protein (PZP), corticosteroid binding globulin (CBG), sex hormone binding globulin (SHBG) and albumin were measured before treatment and during the first and third treatment cycles. AT III levels decreased and alpha 1at levels increased in all three groups during treatment. alpha 2M increased during cycle 3 in the Trinordiol and Gynatrol groups. CBG, PZP and SHBG levels increased in all 3 groups, the CBG and PZP increase being higher in the Marvelon group than in the Gynatrol group. Increases in SHBG levels were found in the order Marvelon > Trinordiol > Gynatrol. Plasma levels of complement factors B, C3 and C4 remained unchanged. It is concluded that the increase in alpha 1at partly compensates for the fall in AT III, that the rise in PZP presumably enhances fibrinolysis, and that LNg has higher anti-estrogenicity and androgenicity than DSG.

Adolescent↗
PubMed1993

Purification and characterization of bovine mannan-binding protein.

Bovine mannan-binding protein (bMBP) was observed in serum by its Ca(2+)-dependent binding to mannan and by an M(r) of 28 kDa under reducing conditions on sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). The lectin was isolated by precipitation with polyethyleneglycol (PEG), affinity chromatography on mannan-Sepharose eluted with EDTA, and absorption on Sepharose 4B rabbit anti-bovine Ig to remove anti-mannan antibodies. Fractions containing the lectin were reapplied to mannan-Sepharose and eluted first with N-acetyl-D-glucosamine (GlcNAc) to remove conglutinin, and then with mannose to elute the 28 kDa lectin. Further purification was achieved by ion-exchange chromatography on Mono-Q and by mannose-gradient elution from a mannan-Sepharose column. SDS-PAGE of the purified lectin showed three high molecular weight bands under non-reducing conditions. The reduced protein gave a single band of 28 kDa. On gel permeation chromatography under non-dissociating conditions, the protein emerged at a volume corresponding to M(r) approximately 750 kDa. Amino acid analysis showed the presence of hydroxyproline and hydroxylysine, and a high glycine content (17.7%), suggesting the presence of a collagen-like structure. This was supported by the susceptibility of the protein to collagenase digestion. The N-terminal 26 amino acids showed 62% identity with human MBP, when three gaps were allowed in the alignment.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1993

Studies on the isolation, structural analysis and tissue localization of fetal antigen 1 and its relation to a human adrenal-specific cDNA, pG2.

Fetal antigen 1 was purified from second trimester human amniotic fluid by immunospecific affinity chromatography followed by reversed-phase chromatography. Fetal antigen 1 is a single chain glycoprotein with a M(r) of 32-38 kDa. The amino acid composition revealed a high content of cysteines, prolines and amino acids (aa) with acidic side-chains indicating that fetal antigen 1 is a compactly folded, strongly hydrophilic molecule. The N-terminal amino acid sequence (37 aa) revealed no homology to other known protein sequences, implying that fetal antigen 1 is a 'novel' human protein. When the aa sequence was back-translated into the appropriate degenerate sequence of nucleic acids, fetal antigen 1 could be partially aligned to a 'human adrenal-specific mRNA, pG2'. The indirect immunoperoxidase technique demonstrated fetal antigen 1 in fetal hepatocytes, glandular cells of fetal pancreas and in fetal adrenal cortex, whereas fetal medullary cells were fetal antigen 1 negative. In adult specimens fetal antigen 1 was exclusively found within the beta cells of the islets of Langerhans and in the adrenals with pronounced staining in the cortex. Our observations suggest that fetal antigen 1 is encoded by the mRNA defined by the cDNA clone pG2, but definitive sequencing and expression studies of this mRNA have not been achieved.

Adrenal Glands↗
PubMed1993

In-vitro synthesis of total protein and placental protein PP14 by the fallopian tube mucosa: variation in relation to anatomical site, the ovarian cycle and the menopause.

De-novo synthesis and secretion of protein by short term explants of mucosa from each anatomical section of the Fallopian tube and endometrium of pre-menopausal (n = 25) and tubal mucosa of post-menopausal (n = 5) women were studied by demonstration of incorporation of radiolabelled L-[35S]methionine and one-dimensional SDS-polyacrylamide gel electrophoresis. A consistent finding in 25 pre-menopausal women was the presence of a 25 kDa protein band synthesized by tissue obtained throughout the ovarian cycle. Western blotting demonstrated that this protein band contained placental protein 14 (PP14)-like immunoreactivity in the proliferative (n = 2) and luteal phase (n = 2) of the ovarian cycle. To determine if there is quantitative variation in total protein and PP14 synthesis and secretion during the ovarian cycle, the total quantities of protein and PP14 synthesized were determined by Coomassie Brilliant Blue staining and radioimmunoassay respectively. Analysis of the results of total protein assay revealed statistically significant differences in relation to the anatomical origin of the study tissue (P < 0.01), the stage of the ovarian cycle (P < 0.04) and the manner in which each anatomical site varied during the ovarian cycle (P < 0.01), the endometrium being significantly different from the Fallopian tube. When the data for PP14 synthesized by the Fallopian tube mucosa were analysed, these effects were not seen. PP14 was not detected in the culture media of Fallopian tube mucosa obtained from post-menopausal women.

Adult↗
PubMed1993

Evidence for the in-vitro de-novo synthesis of immunoglobulin and a previously undescribed 17 kDa protein (TEP-2) by the mucosa of the fallopian tube.

De-novo synthesis and secretion of proteins by short-term explants of matched Fallopian tube mucosa and endometrium were studied using radiolabelled L-[35S]methionine and [3H]glucosamine. To compare directly each anatomical site of the Fallopian tube and endometrium from the same source, newly synthesized proteins were separated on one-dimensional polyacrylamide gel electrophoresis and examined by auto-radiography. De-novo synthesis of two protein bands provisionally designated as tubal epithelial protein 1 (TEP-1) and tubal epithelial protein 2 (TEP-2), was observed in explants of the Fallopian tube mucosa obtained from each anatomical site throughout the ovarian cycle (n = 20). TEP-2 was not apparent in tubal mucosa obtained from post-menopausal women (n = 5). De-novo synthesis of TEP-1 and TEP-2 was not apparent in autoradiographs of radiolabelled proteins from short-term explants of endometrium. From the autoradiographs the molecular mass of TEP-1 and TEP-2 was calculated to be 25 kDa and 17 kDa, respectively. Incorporation of glucosamine into newly synthesized protein occurred in TEP-2 but not TEP-1. TEP-1 was observed to be immunochemically identical to immunoglobulin kappa light chains.

Adult↗
PubMed1993

Low maternal serum levels of pregnancy associated plasma protein A (PAPP-A) in the first trimester in association with abnormal fetal karyotype.

OBJECTIVE: To assess the relation between maternal serum pregnancy associated plasma protein A (PAPP-A) in the first trimester and the outcome of pregnancy by karyotype. DESIGN: A retrospective study of PAPP-A levels in blood samples collected prior to chorionic villus sampling. SETTING: Milan, Italy. SUBJECTS: Five hundred twenty-two women aged 20 to 47, at 7 to 11 weeks gestation, prior to undergoing chorionic villus sampling. Four hundred forty-five women had a pregnancy with a normal karyotype; in 30 pregnancies the karyotype was abnormal (including 14 cases of Down's syndrome and 7 of trisomy 18). MAIN OUTCOME MEASURES: Normal or abnormal fetal karyotype. Serum PAPP-A at 6 to 11 weeks gestation measured by radioimmunoassay. RESULTS: The median value of PAPP-A in the abnormal group was 0.27 multiples of the normal median (MoM). This is significantly lower than the median value in the normal group (1.01 MoM) (95% CI for the difference 0.46-0.84 MoM; P < 0.00001 Mann-Whitney test). CONCLUSIONS: There is an association between low levels of PAPP-A in the first trimester with chromosome anomalies. Screening by measurement of PAPP-A might detect 60% of cases of Down's syndrome in the first trimester with a false positive rate of 5%.

Adult↗
PubMed1992

Calcium-dependent and calcium-independent signals in the conglutinin-binding assay (KgBa) for immune complexes. Influence of anti-collagen-antibodies.

A solid phase ELISA conglutinin-binding assay (KgBa) was evaluated for the detection of circulating immune complexes. ELISA wells were coated with purified bovine conglutinin and incubated with test sera. Bound IgG was detected with enzyme labelled anti-immunoglobulin. Heat aggregated IgG which had been "solubilized" (i.e., complement treated by incubation with serum) was employed as a reference. The binding of the complement-reacted IgG to solid phase conglutinin was found to be calcium-dependent and inhibitable with N-acetyl-D-glucosamine (GlcNAc). Prolonged incubation (4 days) of aggregated IgG with serum at 37 degrees C abolished the binding to conglutinin, a finding consistent with the complete degradation of deposited C3b to C3c and C3d. The solubilized IgG that bound to solid phase conglutinin was found by gel chromatography to be of high molecular weight (greater than 600 kDa). Binding of IgG to solid phase bovine conglutinin was also observed to a variable degree in normal and pathological sera. However, in this situation the IgG binding was largely calcium-independent, was not inhibited by GlcNAc and did not decrease after prolonged incubation of the serum at 37 degrees C. The reactive IgG eluted on gel chromatography at the position of monomeric IgG suggesting binding via the antigen binding sites. Binding of this IgG was inhibited by both collagen type II and purified conglutinin. These observations suggest that the assay detects cross-reacting autoantibodies against collagen epitopes, or, alternatively, antibodies against the dietary antigen, bovine conglutinin.

Acetylgalactosamine↗
PubMed1992

Fetal antigen 2 (FA2) in human fetal osteoblasts, cultured osteoblasts and osteogenic osteosarcoma cells.

Immunohistochemical staining techniques used on an 11-week-old fetus showed that fetal antigen 2 (FA2) was present intracellularly in endochondral and perichondral osteoblasts, and the immunoreaction was extended into the adjacent bone matrix. Osteoclasts and chondroblasts were found to be FA2 negative. A granular perinuclear intracytoplasmic FA2 immunoreaction was found in cultured osteoblasts and osteogenic osteosarcoma cells, and immunoelectron-microscopical examination revealed a granular immunoreaction product in the rough endoplasmic reticulum. These findings indicate that FA2 is synthesized by osteoblasts and osteogenic osteosarcoma cells. A reaction of immunological identity was found between FA2 purified from second trimester amniotic fluid and serum-free supernatants of cultured osteogenic osteosarcoma cells. This shows that an antigen recognized by the anti FA2 antibody is secreted by these malignant cells. Thus, FA2 may represent a marker for altered bone metabolism, and have a potential in the classification of osteogenic osteosarcoma/chondrosarcoma.

Bone and Bones↗
PubMed1992

Quantification of fetal antigen 2 (FA2) in supernatants of cultured osteoblasts, normal human serum, and serum from patients with chronic renal failure.

Fetal antigen 2 (FA2) was found within the cytoplasm of osteoblasts and in osteoid material, in a bone biopsy with morphological changes of renal osteodystrophy. An ELISA technique for FA2 quantification was developed, and the specificity confirmed by comparison with electroimmunoassay. The intra- and interassay coefficient of variations (%) were 8.3 and 9.7 respectively, and the detection limit 0.0004 arbitrary units FA2/1 using second-trimester human amniotic fluid as reference (1 AU FA2/1). FA2 was detected in serum-free supernatants from osteoblast cultures. Following size chromatography, the FA2 distribution (two peaks eluted corresponding to Mw 30 kDa and 100 kDa) in serum from a patient with chronic renal failure complicated with secondary hyperparathyroidism and in human amniotic fluid were identical. Probably due to the detection limit, only one peak fraction (30 kDa) was seen in normal human serum. Significantly greater FA2 concentrations were found in sera (n = 14) from patients with chronic renal failure (median: 11.9 mAU FA2/1; range: 5.2-49.0 mAU FA2/1) compared to normal healthy individuals (n = 23) (median: 4.1 mAU FA2/1; range 2.4-9.4 mAU FA2/1) (P less than 0.00001). A close correlation was found between serum FA2 and alkaline phosphatase (R(s) = 0.761; P = 0.006), c-terminal fraction of PTH (R(s) = 0.872; P = 0.003) and intact PTH(1-84) (R(s) = 0.904; P = 0.011) in the haemodialysis patients. These data indicate that FA2 is synthesized by osteoblasts and may represent a new marker for metabolic bone changes.

Cells, Cultured↗
PubMed1992

Changes induced in serum protein profiles by ovarian stimulation during in-vitro fertilization--embryo transfer treatment: a comparison between conception and non-conception cycles.

The profiles of plasma protein concentrations during the follicular phase in unstimulated women and in women undergoing ovarian stimulation for in-vitro fertilization--embryo transfer (IVF-ET) treatment are described. Plasma protein concentrations are correlated with those of total oestradiol (protein-bound and free) and total progesterone. In addition, 10 conception cycles and 18 non-conception cycles are compared in an attempt to identify predictors of successful treatment. Ovarian stimulation caused a significant increase in follicular phase in serum concentrations of sex hormone binding globulin (SHBG), cortisol binding protein (CBP) and insulin-like growth factor binding protein 1 (IGFBP1). In contrast no increase was observed in unstimulated cycles. Serum levels of endometrial protein PP14 decreased significantly during the follicular phase in both stimulated and unstimulated cycles. Levels of pregnancy zone protein (PZP) were more than doubled at the time of oocyte aspiration compared to the unstimulated cycles. Albumin concentrations were unchanged by the stimulation. Throughout the follicular phase, levels of SHBG were significantly higher, and total oestradiol significantly lower in women who became pregnant, than in those who did not. Therefore, a low concentration of free, biologically active oestradiol seemed to favour pregnancy, as the concentration of albumin is similar in the two groups. The endometrial protein PP14 was significantly lower during the follicular phase in conception than in non-conceptional cycles. On day 2 of the treatment cycle, the PP14 concentration showed a 75% correct prediction of conception and non-conception cycles. These results suggest that levels of PP14 may predict successful IVF cycles even before hormonal treatment is commenced.

Adult↗
PubMed1992

Foetal antigen 2 (FA2) in relation to wound healing and fibroblast proliferation.

During wound healing of human skin the deposition of foetal antigen 2 (FA2) and basement membrane (BM) components collagen type IV and collagen VII was followed. FA2 appeared on day 8 in the cytoplasm of proliferating fibroblasts and around newly formed blood vessels. As granulation tissue was formed, FA2 was seen diffusely in the loose matrix and in proliferating fibroblasts. Re-establishment of FA2 as a broad diffuse band along the BM at the dermo-epidermal junction was seen on day 22. In contrast, type IV and VII collagen were found along the BM and in the basal cells of the newly formed epithelium and a continuous linear BM distribution of these two components were re-established by days 12 and 14, respectively. The molecular weight (Mr) analysis of FA2, isolated from human skin fibroblast culture supernatants using SDS-PAGE, revealed a Mr of 27 kDa, corresponding to that of FA2 isolated from amniotic fluid. The presence of FA2 in proliferating fibroblasts and diffusely in the newly formed matrix of granulation tissue, as well as its late appearance at the BM after this had become established, suggests that FA2 takes part in connective tissue metabolism and perhaps tissue morphogenesis.

Amniotic Fluid↗