Plasminogen activator and collagenase production by cultured capillary endothelial cells

Cultured bovine capillary endothelial (BCE) cells produce low levels of collagenolytic activity and significant amounts of the serine protease plasminogen activator (PA). When grown in the presence of nanomolar quantities of the tumor promoter 12-O-tetradecanoyl phorbol-13-acetate (TPA), BCE cells produced 5-15 times more collagenolytic activity and 2-10 times more PA than untreated cells. The enhanced production of these enzymes was dependent on the dose of TPA used, with maximal response at 10(-7) to 10(-8) M. Phorbol didecanoate (PDD), an analog of TPA which is an active tumor promoter, also increased protease production. 4-O-methyl-TPA and 4α-PDD, two analogs of TPA which are inactive as tumor promoters, had no effect on protease production. Increased PA and collagenase activities were detected within 7.5 and 19 h, respectively, after the addition of TPA. The TPA-stimulated BCE cells synthesized a urokinase-type PA and a typical vertebrate collagenase. BCE cells were compared with bovine aortic endothelial (BAE) cells and bovine embryonic skin (BES) fibroblasts with respect to their production of protease in response to TPA. Under normal growth conditions, low levels of collagenolyic activity were detected in the culture fluids from BCE, BAE, and BES cells. BCE cells produced 5-13 times the basal levels of collagenolytic activity in response to TPA, whereas BAE cells and BES fibroblasts showed a minimal response to TPA. Both BCE and BAE cells exhibited relatively high basal levels of PA, the production of which was stimulated approximately threefold by the addition of TPA. The observation that BCE cells and not BAE cells produced high levels of both PA and collagenase activities in response to TPA demonstrates a significant difference between these two types of endothelial cells and suggests that the enhanced detectable activities are a property unique to bovine capillary and microvessel and endothelial cells.     

Long-distance interactions and principles of molecular recognition at various biosystem organization levels

Efficient molecular recognition, in which recognition processes are occurring much faster than it takes to test variants, is only possible when long-distance recognition occurs together with contact interactions. The distance between interacting molecules should be sufficiently long to prevent hindrances to the search and, on the other hand, sufficiently short to provide selectivity. It was demonstrated that both of these two requirements can be satisfied simultaneously for biological macromolecules that include helical segments. Because the “diameters” of helical molecules are far shorter than their lengths, the intermolecular distance can be far greater than the diameters, thus allowing a free search. The distance can be far shorter than the lengths at the same time, thus providing selectivity. Analytical procedures were developed to estimate the parameters for protein–protein and protein–nucleic acid recognition. The coincidence of the charge-distribution periods in helical segments was found to substantially increase their interaction potential, and the reduction scale characteristic of the potential was shown to depend on the numerical value of the coinciding period.     

A Method to Record the Surface Temperature Distribution of the Skin as a Safe and Ergonomic Approach to Diagnosis and Monitoring in Breast Cancer

Biophysics - Abstract—This article discusses the relevant results on early and safe detection of breast cancer with a thermal volume tomography (TVT) device produced in Russia. The device...     

Long-range interactions between macromolecules, introduced into smectic liquid crystals

Equations for the potentials of interactions between macromolecules of different shapes incorporated into smectic liquid crystals are presented. In addition to accurate equations, simple formula for estimation are given.     

Long-range interactions between macromolecules in ordered media

The results of theoretical calculations of interactions between macromolecules dissolved in ordered media such as liquid crystals and biological membranes (lipid bilayers) are reviewed. Expressions for the potentials of interactions between macromolecules of different shape incorporated into nematic liquid crystals, thin films, and lipid mono- and bilayers were derived. In addition to exact expressions, simple evaluating formulae are given. The two-dimensional "gas" of macromolecules swimming on the membrane was considered, and the expression of state for this "gas" was derived. It was shown that in the "gas", phase transitions accompanied by the formation of two-dimensional clusters may occur. The estimates of critical density at which these transitions occur are given.     

Many-worlds interpretation of quantum theory and fundamental problems of biophysics

The main aspects connected with the many-worlds interpretation of quantum theory are discussed in the article. A possible relation of the interpretation with fundamental biological problems is emphasized. The context of the many-worlds interpretation is discussed in the frames of the so-called “wave function reduction” problem. Thus, some difficulties that arise when we try to imagine how a wave function is reduced in the many-worlds interpretation, are focused on. It is shown that explanations suggested by now as to how the “wave function reduction” happens cannot claim to be the final answer to this question, even though they are not formally contradictory.     

Reparative and neoplastic spheroid cellular structures and their mathematical model

Spheroid cell structures in the cell cultures have been described and are used for studying cell-cell and cell-matrix interactions. At the same time, spheroid cell structure participation in the repair and development of cancer in vivo remains unexplored. The aim of this study was to investigate the cellular composition of spherical structures and their functional significance in the repair of squamous epithelium in human papilloma virus-associated cervical pathology - chronic cervicitis and cervical intraepithelial neoplasia 1–3 degree, and also construct a mathematical model to explain the development and behavior of such spheroid cell structure.     

On the periodicity in the fine structure of histograms during nuclear decay

A possible explanation for the occurrence of periodicity in the fine structure of histograms during nuclear decay is proposed. The hypothesis states that, even in the absence of polarization, when the spin distribution of decaying nuclei over directions is, on the average, isotropic, the fine structure of histograms should depend, due to fluctuations, on the angles at which the sample is observed. There fore, when the Earth after some period would make a full furn, the distribution of fluctuations would return to the initial one, and, correspondingly, the fine structure of the histograms would repeat.     

DNA sequencing using specific long-range interaction between macromolecules

On the basis of the theory of specific long-range interaction between long molecules, an approach has been elaborated for «fast reading» of nucleotide sequences in one DNA molecule. First, a stretching force is applied to the molecule that causes its unwinding from B-form to S-form. Then, the molecule is placed in the stretched state on a support. After this, the electrostatic potential is estimated in a space along the DNA filament. The information obtained is sufficient for deducing the nucleotide sequence. Another approach to the «reading» of information reduces to measurement of the deformation of filament elements induced by the electric field from the electrode that stretches the filament by an alternating current applied.