Håkan Ottosson

• PhD
• Laboratory Manager at Karolinska Institutet

Selenocompounds (SeCs) are promising therapeutic agents for a wide range of diseases including cancer. The treatment results are heterogeneous and dependent on both the chemical species and the concentration of SeCs. Moreover, the mechanisms of action are poorly revealed, which most probably is due to the detection methods where the quantification...

N-acetylcysteine amide (NACA) is the amide derivative of N-acetylcysteine (NAC) that is rapidly converted to NAC after systemic administration. It has emerged as a promising thiol antioxidant for multiple indications; however, the pharmacokinetic property is yet unclear due to lack of an accurate quantification method. The present investigation aim...

Aroylated phenylenediamines (APDs) are novel inducers of innate immunity enhancing cathelicidin gene expression in human bronchial epithelial cell lines. Here we present two newly developed APDs and aimed at defining the response and signaling pathways for these compounds with reference to innate immunity and antimicrobial peptide (AMP) expression....

p-Xyleneselenocyanate (p-XSC) is one of the most investigated selenium compounds in cancer-prevention and -therapy. Despite the potent anti-cancer property, there is still no proper method to perform the quantitative analysis of p-XSC in plasma. In this investigation, we aimed at developing a method based on liquid chromatography-mass spectrometry...

A new concept for treatment of infections is induction of our own antimicrobial peptides and the presented novel class of inducer, aroylated phenylenediamines (APDs), gives up to 20 to 30-fold induction of the human antimicrobial peptide LL-37, in vitro. In addition, oral administration of an APD in a rabbit model of Shigellosis resulted in recover...

Bacterial resistance against classical antibiotics is a growing problem and the development of new antibiotics is limited. Thus, novel alternatives to antibiotics are warranted. Antimicrobial peptides (AMPs) are effector molecules of innate immunity that can be induced by several compounds, including vitamin D and phenyl-butyrate (PBA). Utilizing a...

Innate immunity, the front line of our defence against pathogens, relies, to a great extent, on the production of antimicrobial peptides (AMPs). These peptides exhibit antimicrobial activity and immunomodulatory properties. In humans, AMPs include the defensins (α- and β-families) and the cathelicidin, LL-37. Bacterial resistance against antibiotic...

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Recent work in our laboratory has shown that n-pentenyl glycosides (NPGs) are excellent substrates for a wide variety of reactions occurring at the anomeric center. They are prepared readily by standard glycoside forming procedures, including Fischer's direct method, and although they are stable to a wide range of reagents, they are readily activat...

A general rationalization for armed/disarmed effects, first recognized in n-pentenyl glycosides but recently extended to a variety of other glycosyl donors, is postulated. Reaction of a glycosyl donor with an appropriate electrophile gives a positively charged intermediate which is less favorable when there is an adjacent electron-withdrawing group...

Reaction of p-trifluoroacetamidophenyl 2,4-di-O-benzyl-α-d-mannopyranoside with 2-O-acetyl-3,4,6-tri-O-benzyl-α-d-mannopyranosyl chloride gave a trisaccharide derivative which was O-deacetylated and then treated with ethyl 2,3,4-tri-O-benzyl-6-O-dibenzyloxyphosphoryl-1-thio-α-d- mannopyranoside. The resulting pentasaccharide derivative was deprotec...

Durch Reaktion des Bromids (I) mit dem Mannosid (II) erhält man nach Deblockierung des Kondensationsprodukts das Oligosaccharid (III).

Condensation of 3,6-di-O-acetyl-4-O-(2,3,4,6-tetra-O-acetyl-beta-D-galactopyranosyl)-2-deoxy-2- phthalimido-beta-D-glucopyranosyl bromide with p-nitrophenyl 3-O-benzoyl-4,6-di-O-benzylidene-alpha-D-mannopyranoside, p-nitrophenyl 3,6-di-O-benzyl-alpha-D-mannopyranoside and p-nitrophenyl 3,4-di-O-benzyl-alpha-D-mannopyranoside gave protected tri- and...

Das tritylierte und benzylierte Mannosid (Ib) wird mit dem Lactosaminbromid (II) zum blockierten Trisaccharid (III) kondensiert, das zum freien Trisaccharid (IV) entblockiert wird.