Biomedical subjects

K Sjödin

Publications and source records attributed to K Sjödin.

3 recordsLinked to original sources

PubMed1989

Metabolism of N-acetyl-L-cysteine. Some structural requirements for the deacetylation and consequences for the oral bioavailability.

Rat liver, lung and intestine homogenates deacetylated N-acetyl-L-cysteine. Nearly stoichiometric amounts of L-cysteine were recovered. In rat liver, the enzyme activity was associated with the cytosolic fraction. Liver cytosol was much less active. N-Acetyl-D-cysteine or the disulphide of N-acetyl-L-cysteine were not deacetylated or in other ways consumed in vitro. Isolated, perfused rat liver did not retain or metabolize N-acetyl-L-cysteine to any measurable extent during single-pass experiments. N-Acetyl-L-cysteine or N-acetyl-D-cysteine were injected into a ligated segment of rat intestine in situ. After 1 hr 2% of the L-isomer and 35% of the D-isomer remained in the intestinal lumen. Systemic plasma levels were less than 3 microM of the L-form and congruent to 40 microM of the D-form. We conclude that deacetylation in the intestinal mucosa and possibly in the intestinal lumen is the major factor determining the low oral bioavailability of N-acetyl-L-cysteine. The deacetylation is discussed on the basis of the subcellular localization and the structural requirement of the reaction.

Acetylation↗

PubMed1989

Glutathione in bronchoalveolar lavage fluid from smokers is related to humoral markers of inflammatory cell activity.

Cigarette smoking results in variable degrees of inflammation in the lower respiratory tract. Furthermore, smoking produces oxidant-mediated changes in the lung, important to the pathogenesis of emphysema. Since glutathione can neutralize reactive oxygen species and prevent peroxidation of unsaturated lipids, it may constitute an important component of the lung's defense against oxidant and inflammatory injury. In the present study, broncholaveolar lavage (BAL) was performed in 27 smokers, and the concentrations of total glutathione as well as the cellular and humoral markers of inflammatory activity were studied. There were significant correlations between total glutathione and neutrophils; two neutrophil granule components, myeloperoxidase and elastase; and chemotactic activity for neutrophils. Moreover, the total glutathione correlated with the eosinophil cationic protein (ECP), a granule constituent of the eosinophil, with two locally produced antiproteases, secretory leukocyte protease inhibitor (SLPI) and antichymotrypsin (ACHY), but not with an alpha 1-protease inhibitor and albumin. These data suggest that the total glutathione levels in BAL fluid may reflect a degree of oxidative and inflammatory stress caused by cigarette smoke, and they are therefore likely to contribute to the protection against this stress.

Biomarkers↗

PubMed1986

Streaming potential--a general affinity sensor.

Electrokinetic phenomena, such as streaming potential or streaming current, have so far been used for studies of unspecific adsorption of ionic compounds on various materials. This paper shows that streaming potential measurements can also be used for studies of biospecific interactions. Several different interactions were studied, e.g. lectin-carbohydrate, IgG-Protein A. Regardless of the type of interaction an increasing change in streaming potential was obtained with increasing concentration of the interacting molecule. The authors also observed a correlation between streaming potential and affinity constants for carbohydrate-induced desorption of Concanavalin A from partially hydrolyzed Sephadex G50. In conclusion, it is shown that streaming potential measurements can be used to study molecular interactions, and to determine concentrations and relative binding constants of interacting molecules.

Antigen-Antibody Complex↗