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Landberg, Eva
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Gawria, G., Tillmar, L. & Landberg, E. (2019). A comparison of stability of chemical analytes in plasma from the BD Vacutainer (R) Barricor (TM) tube with mechanical separator versus tubes containing gel separator. Journal of clinical laboratory analysis (Print), Article ID e23060.
Öppna denna publikation i ny flik eller fönster >>A comparison of stability of chemical analytes in plasma from the BD Vacutainer (R) Barricor (TM) tube with mechanical separator versus tubes containing gel separator
2019 (Engelska)Ingår i: Journal of clinical laboratory analysis (Print), ISSN 0887-8013, E-ISSN 1098-2825, artikel-id e23060Artikel i tidskrift (Refereegranskat) Epub ahead of print
Abstract [en]

Background: There is a need of prolonged stability of certain chemical analytes in lithium heparin tubes with separators. A new tube with a mechanical separator has recently been launched (Barricor (TM)), which according to the manufacturer may have these benefits. The aim of this study was to evaluate stability performance of this tube in comparison with plasma gel tubes under clinically realistic circumstances. Methods: Blood was collected in tubes containing lithium heparin with different separators; gel separator (Vacutainer (R) PST (TM), Becton Dickinson and Vacuette (R), Greiner bio-one) and mechanical separator (Vacutainer (R) Barricor (TM), Becton Dickinson). All tubes had an aspiration volume of 3 mL and were centrifuged at similar time and force. Tubes were transported manually or by car. Seven analytes from 122 patients were analyzed after 3 to 80 hours by Cobas c701 (Roche). Results The Barricor (TM) tube showed increased stability of phosphate and potassium and similar stability of aspartate aminotransferase, glucose, homocysteine, lactate dehydrogenase, and magnesium compared with gel tubes. Maximal allowable bias for phosphate was exceeded after 68 hours for Barricor (TM) tubes compared with 29 or 35 hours for gel tubes and for potassium after 40 hours for Barricor (TM) tubes vs 9 or 12 hours for gel tubes. Transportation did not affect stability. Hemolysis index was slightly lower in Barricor tubes than in gel tubes (P = .01). Conclusion Implementing the new Barricor (TM) tube will improve stability of potassium and phosphate in plasma. Blood sampling facilities far from the laboratory may benefit from using these tubes, thus diminishing preanalytical errors.

Ort, förlag, år, upplaga, sidor
WILEY, 2019
Nyckelord
phosphate; plasma; potassium; separator; stability; tube
Nationell ämneskategori
Läkemedelskemi
Identifikatorer
urn:nbn:se:liu:diva-161391 (URN)10.1002/jcla.23060 (DOI)000490068000001 ()31605419 (PubMedID)
Tillgänglig från: 2019-11-04 Skapad: 2019-11-04 Senast uppdaterad: 2019-12-13
Andersson, P., Karlsson, J.-E., Landberg, E., Festin, K. & Nilsson, S. (2015). Consequences of high-sensitivity troponin T testing applied in a primary care population with chest pain compared with a commercially available point-of-care troponin T analysis: an observational prospective study. BMC Research Notes, 8(1), 1-9
Öppna denna publikation i ny flik eller fönster >>Consequences of high-sensitivity troponin T testing applied in a primary care population with chest pain compared with a commercially available point-of-care troponin T analysis: an observational prospective study
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2015 (Engelska)Ingår i: BMC Research Notes, ISSN 1756-0500, E-ISSN 1756-0500, Vol. 8, nr 1, s. 1-9Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

BACKGROUND:There is a demand for a highly sensitive and specific point-of care test to detect acute myocardial infarction (AMI). It is unclear if a high-sensitivity troponin assay will have enough discriminative power to become a decision support in primary care. The aim of this study was to evaluate a high-sensitivity troponin T assay performed in three primary health care centres in southeast Sweden and to compare the outcome with a point-of-care troponin T test.METHODS:This study included 115 patients who consulted their general practitioner for chest pain, dyspnoea on exertion, unexplained weakness and/or fatigue in the last 7days. Troponin T was analysed by a point-of-care test and a high-sensitivity method together with N-terminal pro-B-type natriuretic peptide (NT-proBNP) and creatinine. All patients were checked for AMI or unstable angina (UA) within 30days of study enrolment. Univariate and multivariate logistic regression was carried out to examine possible connections between troponin T[greater than or equal to]15ng/L, clinical variables and laboratory findings at baseline. In addition, 21 patients with troponin T[greater than or equal to]15ng/L and no signs of AMI or UA were followed up for 2-3years.RESULTS:Three patients were diagnosed with AMI and three with UA. At the [greater than or equal to]15ng/L cut-off, the troponin T method had 100% sensitivity, 75% specificity for AMI and a positive predictive value of 10%. The troponin T point-of-care test missed one case of AMI and the detection limit was 50ng/L. Troponin T[greater than or equal to]15ng/L was correlated to age [greater than or equal to]65years (odds ratio (OR), 10.9 95% CI 2.28-51.8) and NT-proBNP in accordance with heart failure (OR 8.62 95% CI 1.61-46.1). Fourteen of the 21 patients, without signs of AMI or UA at baseline, still had increased troponin T at follow-up after 2-3years.CONCLUSIONS:A high-sensitivity troponin T assay could become useful in primary care as a point-of-care test for patients <65years. For patients older than 65-70years, a higher decision limit than [greater than or equal to]15ng/L should be considered and used in conjunction with clinical parameters and possibly with NT-proBNP.

Nyckelord
Primary health care, Acute coronary syndrome, Chest pain, Troponin T, Point-of-care testing
Nationell ämneskategori
Kardiologi
Identifikatorer
urn:nbn:se:liu:diva-122874 (URN)10.1186/s13104-015-1174-0 (DOI)26036786 (PubMedID)
Tillgänglig från: 2015-11-26 Skapad: 2015-11-26 Senast uppdaterad: 2017-12-01
Ekman, B., Wahlberg Topp, J. & Landberg, E. (2015). Urine oligosaccharide pattern in patients with hyperprolactinaemia. Glycoconjugate Journal, 32(8), 635-641
Öppna denna publikation i ny flik eller fönster >>Urine oligosaccharide pattern in patients with hyperprolactinaemia
2015 (Engelska)Ingår i: Glycoconjugate Journal, ISSN 0282-0080, E-ISSN 1573-4986, Vol. 32, nr 8, s. 635-641Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

Free milk-type oligosaccharides are produced during pregnancy and lactation and may have an impact on several cells in the immune system. Our aim was to investigate if patients with isolated hyperprolactinaemia, not related to pregnancy, also have increased synthesis and urinary excretion of milk-type oligosaccharides and to compare the excretion pattern with that found during pregnancy. Urine samples were collected as morning sample from 18 patients with hyperprolactinaemia, 13 healthy controls with normal prolactin levels and four pregnant women. After purification, lactose and free oligosaccharides were analysed and quantified by high-performance anion-exchange chromatography with pulsed amperometric detection. The identity of peaks was confirmed by exoglycosidase treatment and comparison with oligosaccharide standards. Prolactin was measured in serum collected between 09 and 11 a.m. by a standardized immunochemical method. Patients with hyperprolactinaemia had higher urinary excretion of lactose than normoprolactinemic controls and urinary lactose correlated positively to prolactin levels (r = 0.51, p less than 0.05). Increased levels of the fucosylated oligosaccharides 2-fucosyl lactose and lacto-di-fucotetraose were found in urine from three and two patients, respectively. The acidic oligosaccharide 3-sialyl lactose was found in high amount in urine from two patients with prolactin of greater than 10,000 mU/l. However, pregnant women in their third trimester had the highest concentration of all these oligosaccharides and excretion increased during pregnancy. This study is first to show that both lactose and certain fucosylated and sialylated milk-type oligosaccharides are increased in some patients with hyperprolactinaemia. It remains to elucidate the functional importance of these findings.

Ort, förlag, år, upplaga, sidor
SPRINGER, 2015
Nyckelord
Prolactin; Prolactinoma; Urine; Oligosaccharides; Lactose
Nationell ämneskategori
Klinisk medicin
Identifikatorer
urn:nbn:se:liu:diva-122650 (URN)10.1007/s10719-015-9610-x (DOI)000363488300006 ()26275984 (PubMedID)
Anmärkning

Funding Agencies|FORSS (Medical Research Council of Southeast Sweden) [4065]; Faculty of Health and Sciences, Linkoping University, Sweden

Tillgänglig från: 2015-11-16 Skapad: 2015-11-13 Senast uppdaterad: 2017-12-01
Wahlberg Topp, J., Tillmar, L., Ekman, B., Lindahl, T. & Landberg, E. (2013). Effects of prolactin on platelet activation and blood clotting. Scandinavian Journal of Clinical and Laboratory Investigation, 73(3), 221-228
Öppna denna publikation i ny flik eller fönster >>Effects of prolactin on platelet activation and blood clotting
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2013 (Engelska)Ingår i: Scandinavian Journal of Clinical and Laboratory Investigation, ISSN 0036-5513, E-ISSN 1502-7686, Vol. 73, nr 3, s. 221-228Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

Increased levels of prolactin often coincide with an increased risk for thromboembolic events, but it is unclear whether a direct causal relation exists. Our aim was to examine the effect of prolactin on platelet function. In addition to using recombinant prolactin for experiments in vitro, we analyzed platelet function by flow cytometry in a group of 13 females with hyperprolactinaemia and 18 healthy female controls. Platelet activation was measured by P-selectin expression and by the amount of platelet-bound fibrinogen after stimulation with adenosine diphosphate (ADP), collagen-related peptide and the protease activated receptor (thrombin receptor) (PAR)-activating peptides PAR4-AP and PAR1-AP. Free oscillation rheometry was used to measure clotting time in whole blood. No significant effect on platelet activation or clotting time could be seen in in vitro experiments by adding recombinant prolactin. However, significantly lower P-selectin expression was found in the hyperprolactinemic group when platelets were activated by ADP (5 and 10 mu M) or PAR4-AP. The expression of fibrinogen did not differ between the two groups for any of the activators used. For all samples, inverse significant correlations between P-selectin expression and prolactin concentration were found for both 5 mu M ADP (r = 0.61, p andlt; 0.01), 10 mu M ADP (r = -0.62, p andlt; 0.001) and PAR4-AP (r = -0.69, p andlt; 0.001). Thrombin cleavage of recombinant prolactin resulting in a 16 kDa C-terminal fragment did not alter the P-selectin expression upon activation. We found an indirect inhibitory effect of prolactin on platelets in hyperprolactinemic patients, suggesting that prolactin might have a protective role in thromboembolic disease.

Ort, förlag, år, upplaga, sidor
Informa Healthcare, 2013
Nyckelord
Prolactin, platelets, P-selectin, fibrinogen, prolactinoma
Nationell ämneskategori
Medicin och hälsovetenskap
Identifikatorer
urn:nbn:se:liu:diva-92702 (URN)10.3109/00365513.2013.765963 (DOI)000317486400005 ()
Anmärkning

Funding Agencies|FORSS (Medical Research Council of Southeast Sweden)|4065|Faculty of Health and Sciences, Linkoping University, Sweden||

Tillgänglig från: 2013-05-16 Skapad: 2013-05-16 Senast uppdaterad: 2017-12-06
Nilsson, S., Andersson, P. O., Borgquist, L., Grodzinsky, E., Janzon, M., Kvick, M., . . . Karlsson, J.-E. (2013). Point-of-Care Troponin T Testing in the Management of Patients with Chest Pain in the Swedish Primary Care. International Journal of Family Medicine, 2013
Öppna denna publikation i ny flik eller fönster >>Point-of-Care Troponin T Testing in the Management of Patients with Chest Pain in the Swedish Primary Care
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2013 (Engelska)Ingår i: International Journal of Family Medicine, ISSN 2090-2042, E-ISSN 2090-2050, Vol. 2013Artikel i tidskrift (Refereegranskat) Published
Ort, förlag, år, upplaga, sidor
Hindawi Publishing Corporation, 2013
Nationell ämneskategori
Medicin och hälsovetenskap
Identifikatorer
urn:nbn:se:liu:diva-97557 (URN)10.1155/2013/532093 (DOI)
Tillgänglig från: 2013-09-16 Skapad: 2013-09-16 Senast uppdaterad: 2017-12-22
Landberg, E., Åström, E., Kågedal, B. & Påhlsson, P. (2012). Disialo–trisialo bridging of transferrin is due to increased branching and fucosylation of the carbohydrate moiety. Clinica Chimica Acta, 414, 58-64
Öppna denna publikation i ny flik eller fönster >>Disialo–trisialo bridging of transferrin is due to increased branching and fucosylation of the carbohydrate moiety
2012 (Engelska)Ingår i: Clinica Chimica Acta, ISSN 0009-8981, E-ISSN 1873-3492, Vol. 414, s. 58-64Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

Background

Carbohydrate deficient transferrin (CDT) is used for detection of alcohol abuse and follow-up. High performance liquid chromatography (HPLC) of transferrin glycoforms is highly specific for identification of alcohol abuse, but unresolved disialo- and trisialotransferrin glycoforms sometimes makes interpretation difficult. The cause of this phenomenon is unknown, cannot be explained by genetic variants of transferrin, but seems to be associated with liver disease.

Methods

Nineteen serum samples showing di–tri bridging when analyzed by HPLC were collected. Transferrin was purified by affinity chromatography, and N-linked oligosaccharides were released enzymatically. The N-glycans were further analyzed by high performance anion-exchange chromatography with pulsed amperometric detection and MALDI-TOF mass spectrometry.

Results

The HPLC-analysis showed three different types of glycoform patterns. The N-glycans from fifteen samples showed patterns with increased number of triantennary structures containing one or two fucose residues. One sample contained an increased amount of triantennary glycans without fucose. Three samples showed a glycosylation pattern similar to normal transferrin.

Conclusions

The di–tri bridging phenomenon was associated with alterations in transferrin glycosylation in the majority of cases. Transferrin contained a higher extent of triantennary and often fucosylated N-linked oligosaccharides. These results may be important in future diagnostic approaches to liver diseases.

Ort, förlag, år, upplaga, sidor
Elsevier, 2012
Nyckelord
Transferrin, CDT, Di-tri bridging, Glycosylation, Liver disease
Nationell ämneskategori
Medicin och hälsovetenskap
Identifikatorer
urn:nbn:se:liu:diva-88368 (URN)10.1016/j.cca.2012.07.026 (DOI)000312685400014 ()
Anmärkning

Funding Agencies|Medical Research Council of Southeast Sweden||

Tillgänglig från: 2013-04-03 Skapad: 2013-02-04 Senast uppdaterad: 2017-12-06Bibliografiskt granskad
Landberg, E., Dahlström, U. & Alehagen, U. (2011). Serum prolactin and macroprolactin in heart failure: no relation to established laboratory or clinical parameters. ANNALS OF CLINICAL BIOCHEMISTRY, 48, 51-56
Öppna denna publikation i ny flik eller fönster >>Serum prolactin and macroprolactin in heart failure: no relation to established laboratory or clinical parameters
2011 (Engelska)Ingår i: ANNALS OF CLINICAL BIOCHEMISTRY, ISSN 0004-5632, Vol. 48, s. 51-56Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

Background: A few smaller studies have reported that the prolactin concentration is elevated in connection with heart failure. As heart failure is combined with disturbances of several biological systems any or all of which may also influence prolactin concentrations, we wanted to evaluate the relation of prolactin to prognosis in elderly patients. Methods: A total of 462 elderly patients from a primary health-care centre, all with symptoms of heart failure, were included. In addition to clinical examination including echocardiography, concentrations of prolactin, macroprolactin, C-reactive protein, thyroid-stimulating hormone and N-terminal pro B-type natriuretric peptide (NT-proBNP) were measured. Patients were then followed for 10 y, and all incidents of cardiovascular mortality were registered. Results: After excluding patients with macroprolactin, hyperprolactinaemia was found in 3.7% of the patients. There were no differences in prolactin concentrations or in the frequency of macroprolactin between patients with heart failure and those with normal cardiac function, defined as left ventricular ejection fraction of at least 50%. No significant correlation could be found between NT-proBNP and prolactin. Neither could any association be found between cardiovascular mortality and prolactin concentration during 10 y of follow-up. Conclusions: Prolactin concentrations were not associated with cardiovascular mortality or any clinical or biochemical marker of heart failure. Macroprolactin was found in similar frequency among patients with and without heart failure, and showed no correlation with mortality risk.

Ort, förlag, år, upplaga, sidor
Blackwell Scientific Publications, 2011
Nationell ämneskategori
Medicin och hälsovetenskap
Identifikatorer
urn:nbn:se:liu:diva-68354 (URN)10.1258/acb.2010.010164 (DOI)000290425000009 ()
Tillgänglig från: 2011-05-20 Skapad: 2011-05-20 Senast uppdaterad: 2013-09-26
Parenmark, A. & Landberg, E. (2011). To mix or not to mix venous blood samples collected in vacuum tubes?. Clinical Chemistry and Laboratory Medicine, 49(12), 2061-2063
Öppna denna publikation i ny flik eller fönster >>To mix or not to mix venous blood samples collected in vacuum tubes?
2011 (Engelska)Ingår i: Clinical Chemistry and Laboratory Medicine, ISSN 1434-6621, E-ISSN 1437-4331, Vol. 49, nr 12, s. 2061-2063Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

Background: There are recommendations to mix venous blood samples by inverting the tubes immediately after venipuncture. Though mixing allows efficient anticoagulation in plasma tubes and fast initiation of coagulation in serum tubes, the effect on laboratory analyses and risk of haemolysis has not been thoroughly evaluated. less thanbrgreater than less thanbrgreater thanMethods: Venous blood samples were collected by venipuncture in vacuum tubes from 50 patients (10 or 20 patients in each group). Four types of tubes and 18 parameters used in routine clinical chemistry were evaluated. For each patient and tube, three types of mixing strategies were used: instant mixing, no mixing and 5 min of rest followed by mixing. less thanbrgreater than less thanbrgreater thanResults: Most analyses did not differ significantly in samples admitted to different mixing strategies. Plasma lactate dehydrogenase and haemolysis index showed a small but significant increase in samples omitted to instant mixing compared to samples without mixing. However, in one out of twenty non-mixed samples, activated partial thromboplastin time was seriously affected. less thanbrgreater than less thanbrgreater thanConclusions: These results indicate that mixing blood samples after venipuncture is not mandatory for all types of tubes. Instant mixing may introduce interference for those analyses susceptible to haemolysis. However, tubes with liquid-based citrate buffer for coagulation testing should be mixed to avoid clotting.

Ort, förlag, år, upplaga, sidor
Walter de Gruyter, 2011
Nyckelord
haemolysis, mixing, pre-analytical, venipuncture
Nationell ämneskategori
Klinisk laboratoriemedicin
Identifikatorer
urn:nbn:se:liu:diva-75288 (URN)10.1515/CCLM.2011.705 (DOI)000299856700019 ()
Anmärkning

Funding Agencies|Faculty of Health and Sciences, Linkoping University, Sweden|LIO-19451|

Tillgänglig från: 2012-02-27 Skapad: 2012-02-24 Senast uppdaterad: 2017-06-28
Landberg, E., Wahlberg Topp, J., Rydén, I., Arvidsson, B.-M. & Ekman, B. (2007). Detection of molecular variants of prolactin in human serum, evaluation of a method based on ultrafiltration. Clinica Chimica Acta, 376(1-2), 220-225
Öppna denna publikation i ny flik eller fönster >>Detection of molecular variants of prolactin in human serum, evaluation of a method based on ultrafiltration
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2007 (Engelska)Ingår i: Clinica Chimica Acta, ISSN 0009-8981, E-ISSN 1873-3492, Vol. 376, nr 1-2, s. 220-225Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

Background

In human blood, there are several molecular variants of prolactin with different biological effects. There is a need for new methods to detect and quantify these variants in order to fully understand the pathophysiological role of prolactin.

Methods

A method based on ultrafiltration was optimized, validated and compared to PEG precipitation. Serum samples from 84 patients were analyzed before and after pre treatment on two immunoassays, Elecsys (Roche) and Access (Beckman). Protein G precipitation was used to confirm presence of macroprolactin.

Results

The recovery of prolactin after ultrafiltration was lower than after PEG precipitation. A limit of 40% recovery after PEG precipitation corresponded to 27% recovery after ultrafiltration. Using these limits there were total agreement regarding detection of macroprolactin (rs = 0.96). In contrast, recovery of prolactin in samples without macroprolactin showed a considerable disagreement between ultrafiltration and PEG precipitation (rs = 0.48). Within-run CV was 4% for the ultrafiltration method. The correlation coefficient (r) between the immunoassays was 0.96 after ultrafiltration.

Conclusions

Ultrafiltration can be used to compare different prolactin immunoassays and to detect macroprolactin in assays with interference from PEG. For samples without macroprolactin ultrafiltration may give additional information reflecting individual variations of other molecular variants of prolactin.

Nyckelord
Prolactin, Macroprolactin, Ultrafiltration, PEG precipitation
Nationell ämneskategori
Medicin och hälsovetenskap
Identifikatorer
urn:nbn:se:liu:diva-39496 (URN)10.1016/j.cca.2006.08.029 (DOI)49048 (Lokalt ID)49048 (Arkivnummer)49048 (OAI)
Tillgänglig från: 2009-10-10 Skapad: 2009-10-10 Senast uppdaterad: 2017-12-13Bibliografiskt granskad
Landberg, E. (2001). Free oligosaccharides and glycosylation of bile salt-stimulated lipase in human milk. (Doctoral dissertation). Linköping: Linköpings universitet
Öppna denna publikation i ny flik eller fönster >>Free oligosaccharides and glycosylation of bile salt-stimulated lipase in human milk
2001 (Engelska)Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
Abstract [en]

Bile salt-stimulated lipase (BSSL) is a glycosylated protein present in milk at a concentration of 100-200 mg/L. It is an enzyme important for fat digestion in the newborn infant. The protein backbone contains one possible site for N-glyeosylation and several sites for 0-glyeosylation. The glycosylation of BSSL may be important for protection against proteolytic degradation and/or secretion of BSSL. The oligosaeeharides bound to BSSL may also, together with other protein-bound oligosacchatides and free oligosaecharides in milk, play an important role in the defense against pathogenic microorganisms. Human milk contains approximately 5-20 g/L of free milk oligosacchatides, and more than 100 different structures have been identified. There are individual differences in the content of milk oligosaeeharides depending on Lewis and seeretor status.

Milk samples were collected from healthy donors at different times during lactation. BSSL was purified from the milk of five donors. Structural characterization of BSSL glyeosylation was performed by high-performance anionexchange chromatography (HP AEC), Bio-Gel P-4 chromatography, lectin affinity chromatography, gas chromatography coupled to mass-spectrometry (MS) and mattix assisted laser desorption-ionization time-of-flight MS. Certain carbohydrate epitopes were detected by monoclonal antibodies and lectins. Some of the methods above were used in combination with ptior derivatization, desialylation or digestion with different exo- and endoglycosidases. Thirteen major free oligosaccharides were quantified in milk from five individuals. Free milk oligosacchatides were purified by P4-Gel chromatography and analyzed by HPAEC.

HP AEC coupled to pulsed amperometric detection is extensively used for analysis and quantification of oligosaccharides. Separation is achieved using highly alkaline conditions that lead to ionization of some of the hydroxyl groups, which can then interact with the anion-exchange matrix. The effect of colunm temperature was examined in a range of 13 to 40 oC. A large variation in retention times was found depending on small differences in colunm temperature. Moreover, individual oligosaccharides did not show the same temperature dependence. By use of different column temperatures, HP AEC could be optimized for analysis of milk oligosaccharides.

BSSL was found to contain approximately one N-linked and nine O-linked oligosaccharides. The 0-glycans were stmcturally heterogeneous and contained· fucose and/or sialic acid. Each 0-glycan contained an average of eight monosaccharide units. The major N-linked oligosaccharides on human BSSL were mono-sialylated biantennary complex type structures with or without one, two or three fucose residues.

Recombinant human BSSL expressed in CHO and C-127 cells were analyzed and found to be differently glycosylated than native BSSL. In contrast to native BSSL, recombinant BSSL did not contain fucose. On BSSL expressed in C-127 cells, the O-glycans were shorter and more extensively sialylated than O-glycans on native BSSL. The majority of N-linked oligosaccharides on recombinant BSSL had the same core structure (biantennary complex type) as native BSSL.

Glycosylation of BSSL changed during lactation. BSSL had a higher carbohydrate and sialic acid content in the first lactation month. There was also a shift from preferentially α2-6 to α2-3 linked sialic acid on the protein-bound oligosaccharides during lactation. This shift was also found for free sialylated milk oligosaccharides, and suggests a change in the activity of certain sialyltransferases during lactation.

A gradual increase in the expression of the fucosylated carbohydrate epitope Lewis x (Galß1-4[Fucal-3]GlcNAc-) was found on BSSL during the whole lactation period. This was reflected in a higher relative amount of fucosylated N-linked oligosaccharides present on BSSL later in lactation. A similar increase in fucosylation was indicated by analysis of free milk oligosaccharides. One of the major milk oligosaccharides, 3-fucosyllactose (3-FL), also increased in concentration during lactation. However, lacto-N-fucopentaose (LNFIII), the only free milk oligosaccharide containing the Lewis x epitope, showed a constant concentration. This finding does not exclude the possibility that the same fucosyltransferase is involved in the synthesis of Lewis x on BSSL, 3-FL and LNFIII. The precursor of LNFIII, lacto-N-neotetraose (LNnT) showed a marked decrease during lactation, which may explain the different pattem found for LNFIIl. The increase of 3-FL and Lewis x on BSSL was found for all individuals. The other free oligosaccharides studied decreased during lactation, except for lacto-N-fucopentaose li (LNFII), lacto-di-fucotetraose (LDFT) and 3-sialyllactose (3-SL), which showed constant concentrations.

Total fucosyltransferase activity decreased during lactation in milk from both secretors and non-secretors. The specific α1-3 fucosyl transferase activity toward lactose also decreased during lactation, which indicated that fucosyltransferase activity in milk does not reflect the activity in the mammary epithelial cells.

In conclusion, there are changes in glycosylation during lactation, which involves both protein-bound and free milk oligosaccharides. The different patterns for individual oligosaccharides indicate both down and up regulation of certain glycosyltransferases in the mammary gland during lactation. The importance of these changes for the infant's adaptation to the environment remains to be elucidated.

Ort, förlag, år, upplaga, sidor
Linköping: Linköpings universitet, 2001. s. 80
Serie
Linköping University Medical Dissertations, ISSN 0345-0082 ; 657
Nationell ämneskategori
Medicin och hälsovetenskap
Identifikatorer
urn:nbn:se:liu:diva-25676 (URN)10052 (Lokalt ID)91-7219-941-5 (ISBN)10052 (Arkivnummer)10052 (OAI)
Disputation
2001-04-17, Berzeliussalen, Universitetssjukhuset, Linköping, 10:00 (Svenska)
Tillgänglig från: 2009-10-08 Skapad: 2009-10-08 Senast uppdaterad: 2012-08-17Bibliografiskt granskad
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