Biomedical subjects

J Wisniewski

Publications and source records attributed to J Wisniewski.

29 records · Page 2Linked to original sources

PubMed1989

Spreading of cells on various substrates evaluated by Fourier analysis of shape.

In order to evaluate in mathematical terms the morphological changes occurring in the course of cell spreading, Fourier analysis of shape was applied. Human urothelial Hu 961 b cells plated on type IV collagen, fibronectin, laminin, glass and bovine serum albumin (BSA) were studied. Fourier parameters describing cell shape as well as surface areas covered by the cells on the substrate were subjected to statistical analysis. Using analysis of variance and discriminant analysis it was found that parameters describing cell shape (both gross shape of cells and their fine scale contour foldings) possessed a higher power of discrimination between the cells spread on various substrates than the differences in cell surface areas. In the course of observation (75 and 150 min) the highest number of attached cells and highest degree of spreading were found when cells were plated on type IV collagen. Moderate alterations in cell shape and moderate increase of surface area were seen in the group of cells seeded on fibronectin, whereas the cells plated on laminin, glass and BSA revealed a moderate increase of surface area, but no changes in their shape were observed. The differences in attachment of cells and in the degree of their spreading might be due to the variation in expression of plasma membrane receptors for various substrates. The Fourier analysis of cell shape coupled with measurement of surface area is a good tool for quantitative evaluation of cell spreading and can be used for discrimination between cells spread on different substrates.

Cell Adhesion↗

PubMed1988

A rat testis-specific hsp70 gene-related transcript is coded by a novel gene from the hsp70 multigene family.

To establish the identity of testis-specific hsp70 gene-related transcript, the expression pattern of the hsp70 gene family in testis and liver of rats subjected to whole body hyperthermia was investigated. In control liver two hsp70 gene-related transcripts of about 2.2 and 2.5 kb were detected. Increased body temperature resulted in high accumulation of 2.5 kb RNA and in the appearance of abundant amounts of another heat-induced transcript of approx. 2.7 kb. In testis of control rats only one hsp70 gene-related transcript has been identified and hyperthermia did not affect its level. This transcript migrated in 1% agarose-formaldehyde gel slightly faster than the 2.5 kb heat-induced RNA detected in liver and epididymis. The uniqueness of the testicular hsp70 gene-related transcript has been confirmed by its hybridization properties. At stringent conditions this transcript did not hybridize with a human hsp70 gene-related probe in contrast to the 2.5 and 2.7 kb heat-induced RNA species.

Animals↗

PubMed1983

Hydrophobic ion probe studies of membrane dipole potentials.

Hydrophobic anions of dipicrylamine and of sodium tetraphenylborate have been employed as probes of interfacial dipole potential variations in lipid bilayer membranes. Systematic variation of dipole potentials has been achieved by introduction of compounds incorporating N+ and B- charge centers. Distribution of hydrophilic and hydrophobic groups relative to these charge centers has been shown to control the orientation in the membrane/solution interface of the electric dipole moment formed by these centers. Thus triphenyl-[4-trimethylphenylammonium] borate orients with the B- center, surrounded by phenyl groups, embedded in the membrane, while the smaller methylated N+ center is directed toward the aqueous phases. This orientation has been confirmed using dipicrylamine probe ions. Results obtained in this system have been interpreted quantitatively using a previously developed model incorporating discrete charge effects. A second class of compounds, tri-n-alkylamine borane (TnAB) complexes having the generic formula (CnH2n+1)3N+B-H3, have also been synthesized for this study, using even-carbon alkyls ranging from ethyl to decyl. Molecular orientation of the complex is with the N+ center and its associated alkyl groups directed into the membranes, while the protonated B- center is directed toward the aqueous phases, as confirmed by use of tetraphenylborate ions as probes.

Lipid Bilayers↗

PubMed1979