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Biomedical subjects

L Lindén

Publications and source records attributed to L Lindén.

18 recordsLinked to original sources
PubMed1996

Engagement of L-selectin impairs the actin polymerizing capacity of beta 2-integrins on neutrophils.

A sequential activation of L-selectin and beta 2-integrins on neutrophils is crucial for the rolling, adherence and subsequent migration of these cells on the endothelium. However, little is known about a possible interplay between these adhesion receptors in the final regulation of cell motility. The results presented here show that sulfatides themselves (here used as tools to activate L-selectins), have no major effect on the cellular content of filamentous actin (F-actin), but cause a time-related decrease in the beta 2-integrin-induced formation of F-actin. This effect of sulfatides was abolished in cells lacking L-selectin as a result of pretreatment with chymotrypsin. A similar sulfatide-induced activation of L-selectin also caused a pronounced and time-related decrease of a subsequent chemotactic peptide-induced F-actin response. The effect of sulfatides on both beta 2-integrin- and chemotactic peptide-induced F-actin were abolished if L-selectin were blocked by preincubating the cells with specific antibodies to L-selectin. These effects of L-selectin engagement on cellular F-actin content were neither abolished by blocking the cytosolic free Ca2+ signal with bis-(2-amino-5-methylphenoxy)ethane-N,N,N',N'-tetraaceticacid tetraacetoxymethyly ester (MAPT/AM) nor by blocking a cAMP-induced activation of protein kinase A by pretreating the cells with adenosine-3',5'-cyclic monophos-phorothioate (Rp-cAMPS). Instead we found that L-selectin engagement impaired an early beta 2-integrin-induced tyrosine kinase activation, an event shown to be necessary for a normal beta 2-integrin-mediated F-actin response. The present demonstration of a negative feed-back function of L-selectin on beta 2-integrin-induced modulations of the actin cytoskeleton, suggests that the relative distribution and/or density of the respective L-selectin and beta 2-integrin ligands on endothelial cells might be important factors in determining the final site of firm adhesion and extravasation of neutrophils.

Actins↗
PubMed1985

Diffusion of fluoride from alginate compared with other topical fluoride agents.

A two-chamber diffusion cell has been employed to monitor the diffusion of fluoride (F) from F-containing agents. The F which diffused from fluoridated alginate-base formula, F-containing gel (Gelution) and varnish (Duraphat) was determined within the first 6 or 20 min in unstirred conditions. A comparative analysis of the data showed that the alginate-base formula was efficient in releasing F. The results also indicate that the diffused F was not directly related to the total F content in the products or the bulkiness of the test specimens. It is obvious that the physicochemical properties of the products play a determining role in the release of F.

Acidulated Phosphate Fluoride↗
PubMed1976

Studies on an additional pre-beta-lipoprotein, sinking pre-beta (SPB). I. Isolation and characterization.

The occurrence on cellulose acetate and agarose gel electrophoresis of additional bands with the mobility of pre-beta-lipoprotein (LP) has recently been linked to ischemic heart disease (IHD). In the present study, one of these additional pre-beta-LP fractions, earlier designated as 'pre-beta-LP' and now defined on agarose gel electrophoresis, was isolated by preparative ultracentrifugation and gel filtration. The characterization of this pre-beta-1-LP revealed a 'sinking pre-beta-LP' (SPB) of density 1.050-1.080 g/ml. SPB shared its major antigenic determinant with low-density lipoproteins (LDL) and resembled closely LDL with regard to its lipid composition. Specific anti-LP(a) serum confirmed the presence of LP(a) antigen in the purified SPB preparation.

Electrophoresis, Agar Gel↗
PubMed1976

Studies on an additional pre-beta-lipoprotein, sinking pre-beta (SPB). II. Fatty acid composition of lipid moieties.

The appearance of additional lipoprotein fractions with pre-beta-mobility on cellulose acetate and agarose gel electrophoresis has recently been linked with the early occurrence of ischemic heart disease (IHD). One of these fractions, designated sinking pre-beta-lipoprotein (SPB) has been isolated, purified, and identififed as synonymous with LP(a). In the present study, the lipid moieties of this lipoprotein fraction were further characterized as to their fatty acid composition. These were almost identical to those of low-density lipoprotein (LDL) lipid moieties. The acute influence on fatty acid composition of SPB lipid moieties, 5 hr after a linoleic acid-rich test meal, was a 40% increase in triglyceride linoleic acid content and only minor changes in phosphoglyceride fatty acids. Data speak against an actual conversion of chylomicron remnants into SPB but would allow a certain exchange of lipid moiety among chylomicrons, SPB, and LDL. It is therefore suggested that the origin of the SPB presumably synonymous with LP(a) is the same as for LDL: the liver.

Chromatography, Gas↗