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Biomedical subjects

M Bracke

Publications and source records attributed to M Bracke.

51 records · Page 3Linked to original sources
PubMed1987

Human anti-alpha-galactosyl IgG reduces the lung colonization by murine MO4 cells.

The lung colonization of MO4 cells, a highly malignant murine cell line, is strongly reduced in syngeneic C3H/He mice by a prior incubation with anti-alpha-galactosyl antibody (alpha-Gal Ab), a natural IgG antibody present in high titers in all normal human sera and specifically recognizing Gal alpha(1----3) structures (alpha-D-galactopyranosyl; alpha-D-Galp). The protective effect is due to a binding of alpha-Gal Ab to alpha-D-Galp end groups of MO4 cells, inducing both an increase in their sequestration into the liver and the spleen and a decrease in their sequestration into the lung. The F(ab')2 fragments of this antibody also exhibit a protective effect by inhibiting the homing of MO4 cells into the lung, without modifying their accumulation into the spleen and the liver. Since both the antibody and the alpha-galactosidase pretreatments of MO4 cells block their subsequent attachment to murine laminin in vitro, we suggest that, in this model, the lung colonization may be dependent on the alpha-D-Galp end groups exposed on the surface of MO4 cells.

Animals↗
PubMed1980

Cardiotoxicity of ritodrine: assessment based on serum creatine kinase activity.

Thirty-three gravidas undergoing chronic tocolysis with ritodrine were assessed with respect to potential drug-induced cardiotoxic effects. The immunological and electrophoretic determination of serum creatine kinase activity gave no indication of such effects. The results of this study confirm the significant increase reported for the serum activity of the MB, BB, and MM creatine kinase isoenzymes during the post-partum period. In most cases no difference was found between the isoenzyme distribution pattern characterizing acute myocardial infarction and normal labor, and therefore the measurement of serum creatine kinase activity during labor has no value for the diagnosis of acute myocardial infarction.

Creatine Kinase↗
PubMed1978

Differential spectrophotometric determination of tyrosine and tryptophan in pharmaceutical amino acid solutions.

A method is proposed for the simultaneous determination of tyrosine and tryptophan in solutions by differential spectrophotometry. The concentrations are calculated from the measurement of the absorbance of the amino acid mixture in an alkaline medium and from the differential absorbance of the alkaline solution against the acid solution at 294.4 nm. A comparison with three other well-known methods is discussed.

Drug Combinations↗
PubMedDate not supplied

Arrest of MCF-7 cell migration by laminin in vitro: possible mechanisms.

Laminin, a major basement membrane component, arrested the migration of MCF-7/AZ human breast adenocarcinoma cells that were not invasive in vitro. Migration of invasive MCF-7/6 cells was not affected by laminin. Both cell types expressed the 67 kD laminin receptor, at both mRNA and protein level, but did not express the alpha 6 subunit of the VLA-6 integrin-type laminin receptor. The presence of YIGSR peptides (100 micrograms/ml), reported to block the interaction between laminin and its 67 kD receptor, did not change the migratory response of MCF-7/AZ or MCF-7/6 cells when meeting laminin lanes. In addition, the migration of these cell types was not affected by the presence of 17-beta-estradiol (10(-6) M) or all-trans retinoic acid (10(-6) M), which were both reported to increase the number of 67 kD receptors. We could therefore not assign an involvement of the 67 kD receptors in migration of MCF-7 cells on laminin, nor did we find evidence that conditioned medium of MCF-7/6 cells contains factors that are able to initiate migration of MCF-7/AZ cells on laminin.

Adenocarcinoma↗
PubMedDate not supplied

Effect of catechins and citrus flavonoids on invasion in vitro.

Catechins, a group of flavonoid molecules, inhibit invasion of mouse MO4 cells into embryonic chick heart fragments in vitro. The anti-invasive effects can be ranked as follows: (+)-catechin greater than (-)-epicatechin greater than 3-O-methyl-(+)-catechin greater than 3-O-palmitoyl-(+)-catechin. Most of the catechins are unstable in cell culture media, and their spontaneous rearrangement products tend to bind to extracellular matrix (ECM). Due to these interactions proteases such as tissue-type plasminogen activator (t-PA) are linked to the ECM glycoprotein laminin. This leads to a partial inactivation of the enzyme. Within the group of catechins we found a positive correlation between anti-invasive activity and linking of t-PA to laminin. Citrus flavonoids are also anti-invasive in vitro (tangeretin greater than nobiletin greater than hesperidin = naringin). However, these stable molecules show poor affinity for ECM, and do not link enzymes to laminin. These data suggest that catechins and citrus flavonoids inhibit invasion in vitro by different mechanisms.

Animals↗
PubMedDate not supplied

Cellular and molecular mechanisms of metastasis as applied to carcinomatous meningitis.

Cancer cells as well as bacteria metastasize to the subarachnoidal space (SAS) causing meningitis. Primary brain tumors, although not forming distant metastases, disseminate via the cerebrospinal fluid and occupy the meninges. The multistep process of cancer or bacterial dissemination is regulated through molecular crosstalk between invaders and host cells. Such crosstalks establish invasion-promoter and invasion-suppressor complexes. In carcinomatous and bacterial meningitis, the participation of host cells is prominent since leukocytes and inflammatory cytokines are the major determinants of malignancy. We propose a model in which bacterial breakdown products activate endothelial cells, a process leading to leukocyte extravasation. This initiates a cascade of inflammatory processes opening up the blood cerebrospinal fluid barrier and producing access for new invaders.

Astrocytoma↗
PubMedDate not supplied

Heterotransplantation of primary and established human tumour cells in nude mice.

Previous successful transplantations of human tumour cells into athymic nude mice have been described when cells were injected with a reconstituted basement membrane (matrigel). We have compared the development and the histology of tumours following injection with matrigel or with culture medium of a panel of tumour cells exhibiting different degrees of tumorigenicity. Two cell lines (MCF7 and MCF7/6) required matrigel in order to form tumours. When inoculated with matrigel, all the other cell lines tested [MCF7 gpt, MCF7ras, MCF7(AZ), MCF7(AZ)TD5, MDA-MB 231, HT1080] showed increased tumour take and reduced latency period. Human primary tumours (melanoma, breast and colon cancers) were transplanted successfully into nude mice, in the presence of matrigel. Breast primary tumours or cell lines gave rise to poorly differentiated carcinomas. The other tumours presented histopathological patterns typical of differentiated human cancers.

Adenocarcinoma↗