Biomedical subjects

I Giaever

Publications and source records attributed to I Giaever.

4 recordsLinked to original sources

PubMed1992

Electrical method for detection of endothelial cell shape change in real time: assessment of endothelial barrier function.

We have developed an electrical method to study endothelial cell shape changes in real time in order to examine the mechanisms of alterations in the endothelial barrier function. Endothelial shape changes were quantified by using a monolayer of endothelial cells grown on a small (10(-3) cm2) evaporated gold electrode and measuring the changes in electrical impedance. Bovine pulmonary microvessel endothelial cells and bovine pulmonary artery endothelial cells were used to study the effects of alpha-thrombin on cell-shape dynamics by the impedance measurement. alpha-Thrombin produced a dose-dependent decrease in impedance that occurred within 0.5 min in both cell types, indicative of retraction of endothelial cells and widening of interendothelial junctions because of "rounding up" of the cells. The alpha-thrombin-induced decrease in impedance persisted for approximately 2 hr, after which the value recovered to basal levels. Pretreatment of endothelial cells with the protein kinase C inhibitor, calphostin C, or with 8-bromoadenosine 3',5'-cyclic monophosphate prevented the decreased impedance, suggesting that the endothelial cell change is modulated by activation of second-messenger pathways. The alpha-thrombin-induced decrease in impedance was in agreement with the previously observed increases in transendothelial albumin permeability and evidence of formation of intercellular gaps after alpha-thrombin challenge. The impedance measurement may be a valuable in vitro method for the assessment of mechanisms of decreased endothelial barrier function occurring with inflammatory mediators. Since the rapidly occurring changes in endothelial cell shape in response to mediators such as thrombin are mediated activation of second-messenger pathways, the ability to monitor endothelial cell dynamics in real time may provide insights into the signal-transduction events mediating the increased endothelial permeability.

Animals↗

PubMed1978

A simple visual surface immunology test.

A new general immunology test is described which is capable of detecting protein in the 1 microgram/ml range. First an antigen is adsorbed in a small area of a glass surface. The glass is exposed to an antibody solution and the antibody will attach specifically to the antigen. Next the slide is washed, dried and sprayed lightly with plastic particles that stick to the protein layers on the glass. Now when the glass slide is exposed to an acid the antigen--antibody bonds are broken, the antibodies will leave the surface removing some of the plastic particles and leaving an easily visible spot behind.

Animals↗

PubMed1978

Cell adhesion to substrates containing adsorbed or attached IgG.

When most mammalian cells are propagated in tissue culture, they are attached to a solid surface. This surface is commonly covered with a layer of serum protein. In this study we looked at the effect of the protein layer on the interaction between the cells and the surface by precoating the surface with various pure protein molecules. We found no differences between surfaces covered with pure protein layers and those covered with serum proteins except when antibody molecules were used. In all cases the cell types used avoided surfaces covered with antibody molecules. Previously, other investigators have established that some cells belonging to the immunology system are attracted to such surfaces.

Antigen-Antibody Complex↗

PubMed1976

Visual detection of carcinoembryonic antigen on surfaces.

An attempt is made to detect carcinoembryonic antigen (CEA) at clinically interesting concentrations by using a simple immunologic surface test. Antibodies to CEA are detected in a direct test at concentrations below 1 ng/ml. The sensitivity of this assay is mainly limited by diffusion to the reacting surface. CEA is detected in an inhibition test at concentrations down to 20 ng/ml. The sensitivity of this inhibition test is limited by the average equilibrium constant in solution of the antibody-antigen reaction.

Adsorption↗