Glycosphingolipids Recognized by Acinetobacter baumannii

Acinetobacter baumannii is an opportunistic bacterial pathogen associated with hospital-acquired infections, including pneumonia, meningitis, bacteremia, urinary tract infection, and wound infections. Recognition of host cell surface carbohydrates plays a crucial role in adhesion and enables microbes to colonize different host niches. Here the potential glycosphingolipid receptors of A. baumannii were examined by binding of S-35-labeled bacteria to glycosphingolipids on thin-layer chromatograms. Thereby a selective interaction with two non-acid glycosphingolipids of human and rabbit small intestine was found. The binding-active glycosphingolipids were isolated and, on the basis of mass spectrometry, identified as neolactotetraosylceramide (Gal beta 4GlcNAc beta 3Gal beta 4Glc beta 1Cer) and lactotetraosylceramide (Gal beta 3GlcNAc beta 3Gal beta 4Glc beta 1Cer). Further binding assays using reference glycosphingolipids showed that A. baumannii also bound to lactotriaosylceramide (GlcNAc beta 3Gal beta 4Glc beta 1Cer) demonstrating that GlcNAc was the basic element recognized. In addition, the bacteria occasionally bound to galactosylceramide, lactosylceramide with phytosphingosine and/or hydroxy fatty acids, isoglobotriaosylceramide, gangliotriaosylceramide, and gangliotetraosylceramide, in analogy with binding patterns that previously have been described for other bacteria classified as "lactosylceramide-binding". Finally, by isolation and characterization of glycosphingolipids from human skin, the presence of neolactotetraosylceramide was demonstrated in this A. baumannii target tissue

Characterization of Human Medullary Thyroid Carcinoma Glycosphingolipids Identifies Potential Cancer Markers

Medullary thyroid carcinoma (MTC) accounts for only 1–2% of thyroid cancers; however, metastatic MTC is a mortal disease with no cure. In this study, glycosphingolipids were isolated from human MTCs and characterized by mass spectrometry and binding of carbohydrate recognizing ligands. The tissue distribution of selected compounds was investigated by immunohistochemistry. The amount of acid glycosphingolipids in the MTCs was higher than in the normal thyroid glands. The major acid glycosphingolipid was the GD3 ganglioside. Sulfatide and the gangliosides GM3 and GD1a were also present. The majority of the complex non-acid glycosphingolipids had type 2 (Galβ4GlcNAc) core chains, i.e., the neolactotetraosylceramide, the Lex, H type 2 and x2 pentaosylceramides, the Ley and A type 2 hexaosylceramides, and the A type 2 heptaosylceramide. There were also compounds with globo (GalαGalβ4Glc) core, i.e., globotriaosylceramide, globotetraosylceramide, the Forssman pentaosylceramide, and the Globo H hexaosylceramide. Immunohistochemistry demonstrated an extensive expression av Ley in the MTC cells and also a variable intensity and prevalence of Globo H and Lex. One individual with multiple endocrine neoplasia type 2B expressed the Forssman determinant, which is rarely found in humans. This study of human MTC glycosphingolipids identifies glycans that could serve as potential tumor-specific markers

Potential application in regenerative medicine for treatment of terminal cell and organ failure

The major limiting factor in the treatment of patients with end-stage organ failure is the insufficient number of human organs available for transplantation. An unlimited access to human cells, tissues and organs would also open up possibilities to treat several chronic diseases, such as diabetes, neurological and cardiovascular diseases, affecting millions of patients worldwide. Cells and tissues derived from human pluripotent stem cells (hPSC) could potentially fulfill these ambitions. However, there are several biomedical barriers to overcome before this can be a clinical reality. One of the most important concerns is the immunogenicity of the conceivable cell or tissue grafts derived from hPSC when exposed to a non-self recipient. This thesis explores the expression of immunogenic tissue HLA and blood group antigens in several hPSC cell lines and their derivatives. This characterization was performed by several complementary analytical techniques, such as flow cytometry, immunohistochemistry, PCR, as well as biochemical characterization of glycosphingolipid molecular structures and protein bound antigen composition. The results demonstrate that pluripotent stem cells express various cell surface immunodeterminants including HLA, AB(O)H and related histo-blood group antigens. Moreover, we identified significant alterations of antigen expression patterns during endodermal, mesodermal and ectodermal differentiation. Consequently, our results indicate that all hPSC-derived cells intended for clinical applications should be characterized regarding their individual tissue antigen profile in accordance with the standard selection criteria used in allotransplantation. Furthermore, we identified a novel cell surface marker of undifferentiated stem cells, sialyl-lactotetra, which can be used as a verification and selection tool for pluripotency, as well as a potential exclusion measure in heterogeneously differentiated cell cultures to prevent tumor formation. In conclusion, this thesis adds new knowledge regarding cell surface antigen expression in hPSC of relevance both for basic science and for future clinical applications within transplantation and regenerative medicine

Characterization of Glycosphingolipids in the Human Parathyroid and Thyroid Glands

As part of a systematic investigation of the glycosphingolipids in human tissues, acid and non-acid glycosphingolipids from human thyroid and parathyroid glands were isolated and characterized with mass spectrometry and binding of carbohydrate-recognizing ligands, with a focus on complex compounds. The glycosphingolipid patterns of the human parathyroid and thyroid glands were very similar. The major acid glycosphingolipids were sulfatide and the gangliosides GM3, GD3, GD1a, GD1b, GT1b and Neu5Ac-neolactotetraosylceramide, and the major non-acid glycosphingolipids were globotriaosylceramide and globoside. We also found neolactotetra- and neolactohexaosylceramide, the x2 glycosphingolipid, and complex glycosphingolipids with terminal blood group O and A determinants in both tissues. A glycosphingolipid with blood group Leb determinant was identified in the thyroid gland, and the parathyroid sample had a glycosphingolipid with terminal blood group B determinant. Immunohistochemistry demonstrated the expression of blood group A antigens in both the thyroid and parathyroid glands. A weak cytoplasmatic expression of the GD1a ganglioside was present in the thyroid, while the parathyroid gland had a strong GD1a expression on the cell surface. Thus, the glycosylation of human thyroid and parathyroid glands is more complex than previously appreciated. Our findings provide a platform for further studies of alterations of cell surface glycosphingolipids in thyroid and parathyroid cancers

Patient-doctor communication on smoking and drinking: Lifestyle in medical consultations

Lifestyles of groups and individuals are significant determinants of the health status of a population. Behaviour with respect to such areas as alcohol, food, drugs, tobacco, physical exercise, etc., correlates with medical and social well-being and are thus on the agenda for modern health care. The present article reports a study of how such lifestyle habits, notably alcohol and tobacco consumption, are addressed in medical consultations. The results indicate that the areas of smoking and drinking are sensitive and that specific communicative strategies are used for introducing these topics and for eliciting information. Smoking habits are addressed in 75% of the consultations and alcohol habits in 30%. In most cases, the information exchanged is shallow and gives only a fragmentary picture of patients' habits. There is little evidence of attempts to influence patients' attitudes and behaviours and the physicians do not contextualise possible relationships between such lifestyle habits and health in the light of their medical knowledge. In this sense, a potentially very influential face-to-face encounter is not used as a vehicle for attempting to eliminate such significant causes of poor health.patient-doctor communication medical consultations lifestyle habits smoking drinking

Characterization of Human Medullary Thyroid Carcinoma Glycosphingolipids Identifies Potential Cancer Markers

Medullary thyroid carcinoma (MTC) accounts for only 1-2% of thyroid cancers; however, metastatic MTC is a mortal disease with no cure. In this study, glycosphingolipids were isolated from human MTCs and characterized by mass spectrometry and binding of carbohydrate recognizing ligands. The tissue distribution of selected compounds was investigated by immunohistochemistry. The amount of acid glycosphingolipids in the MTCs was higher than in the normal thyroid glands. The major acid glycosphingolipid was the GD3 ganglioside. Sulfatide and the gangliosides GM3 and GD1a were also present. The majority of the complex non-acid glycosphingolipids had type 2 (Gal beta 4GlcNAc) core chains, i.e., the neolactotetraosylceramide, the Le(x), H type 2 and x(2) pentaosylceramides, the Le(y) and A type 2 hexaosylceramides, and the A type 2 heptaosylceramide. There were also compounds with globo (Gal alpha Gal beta 4Glc) core, i.e., globotriaosylceramide, globotetraosylceramide, the Forssman pentaosylceramide, and the Globo H hexaosylceramide. Immunohistochemistry demonstrated an extensive expression av Le(y) in the MTC cells and also a variable intensity and prevalence of Globo H and Le(x). One individual with multiple endocrine neoplasia type 2B expressed the Forssman determinant, which is rarely found in humans. This study of human MTC glycosphingolipids identifies glycans that could serve as potential tumor-specific markers.</p&gt

Characterization of Glycosphingolipids in the Human Parathyroid and Thyroid Glands

As part of a systematic investigation of the glycosphingolipids in human tissues, acid and non-acid glycosphingolipids from human thyroid and parathyroid glands were isolated and characterized with mass spectrometry and binding of carbohydrate-recognizing ligands, with a focus on complex compounds. The glycosphingolipid patterns of the human parathyroid and thyroid glands were very similar. The major acid glycosphingolipids were sulfatide and the gangliosides GM3, GD3, GD1a, GD1b, GT1b and Neu5Ac-neolactotetraosylceramide, and the major non-acid glycosphingolipids were globotriaosylceramide and globoside. We also found neolactotetra- and neolactohexaosylceramide, the x(2) glycosphingolipid, and complex glycosphingolipids with terminal blood group O and A determinants in both tissues. A glycosphingolipid with blood group Le(b) determinant was identified in the thyroid gland, and the parathyroid sample had a glycosphingolipid with terminal blood group B determinant. Immunohistochemistry demonstrated the expression of blood group A antigens in both the thyroid and parathyroid glands. A weak cytoplasmatic expression of the GD1a ganglioside was present in the thyroid, while the parathyroid gland had a strong GD1a expression on the cell surface. Thus, the glycosylation of human thyroid and parathyroid glands is more complex than previously appreciated. Our findings provide a platform for further studies of alterations of cell surface glycosphingolipids in thyroid and parathyroid cancers.De två första författarna delar förstaförfattarskapet.</p

Characterization of glycosphingolipids from gastrointestinal stromal tumours

Gastrointestinal stromal tumours (GISTs) are the major nonepithelial neoplasms of the human gastrointestinal tract with a worldwide incidence between 11 and 15 per million cases annually. In this study the acid and non-acid glycosphingolipids of three GISTs were characterized using a combination of thin-layer chromatography, chemical staining, binding of carbohydrate recognizing ligands, and mass spectrometry. In the non-acid glycosphingolipid fractions of the tumors globotetraosylceramide, neolactotetraosylceramide, and glycosphingolipids with terminal blood group A, B, H, Lex, Lea, Ley and Leb determinants were found. The relative amounts of these non-acid compounds were different in the three tumour samples. The acid glycosphingolipid fractions had sulfatide, and the gangliosides GM3, GD3, GM1, Neu5Acα3neolactotetraosylceramide, GD1a, GT1b and GQ1b. In summary, we have characterized the glycosphingolipids of GISTs and found that the pattern differs in tumours from different individuals. This detailed characterization of glycosphingolipid composition of GISTs could contribute to recognition of new molecular targets for GIST treatment and sub-classification