ABSTRACT
The quantitative estimation of safe contraction for the soft tissue cancer detection procedure is presented, which is based on the classical analytical solution for the concentration of stress around spherical inclusions and flaws in elastic media.
Subject(s)
Palpation/methods , Soft Tissue Neoplasms/diagnosis , Elasticity , Humans , Soft Tissue Neoplasms/pathologyABSTRACT
The diagnostic importance of the mechanical properties of pathologically altered soft biological tissues is substantiated. The data on elastic properties of prostate and mammary gland obtained on postoperational material are presented. The methods of treating the experimental data used to determine these characteristics are described.
Subject(s)
Breast Neoplasms/physiopathology , Breast/physiopathology , Prostate/physiopathology , Prostatic Neoplasms/physiopathology , Biomechanical Phenomena , Breast/cytology , Elasticity , Female , Humans , Male , Prostate/cytologyABSTRACT
The mechanical parameters of the skin and scarring tissues were assessed in children aged 3-14 years who had various scar types, by using an ACA apparatus, which measures the propagation rates of superficial acoustic waves in the skin. It was found that the types (atrophic, hypertrophic, keloid) of scars could be significantly differentiated from the value of this parameter. The comparison of clinical and acoustic data shows high (as high as 90%) significance of the latter.
Subject(s)
Acoustics , Cicatrix/pathology , Adolescent , Atrophy , Child , Child, Preschool , Cicatrix, Hypertrophic/pathology , Diagnosis, Differential , Humans , Keloid/pathology , Skin/pathologyABSTRACT
The values of apparent adiabatic compressibility of free and antigen-bound antibodies were determined by means of precise density and ultrasound velocity measurements. It was shown that during the formation of soluble immune complexes (insulin--monoclonal antibodies to insulin and alpha-amylase--monovalent Fab-fragments of antibodies to alpha-amylase), the apparent compressibility of antibodies decreased by (0.3 divided by 0.9).10(-6) cm3/g.bar. During the formation of large insoluble aggregates (alpha-amylase--polyclonal antibodies to alpha-amylase), the apparent compressibility decreased by (5.5 +/- 0.7).10(-6) cm3/g.bar. It is suggested that the decrease in the magnitude of thermal fluctuations of the molecular volume of antibodies during antigen binding, manifesting itself by the decrease in their compressibility and strengthened several-fold by precipitate formation, may favour the activation of the effectory functions of antibodies.
Subject(s)
Antibodies, Monoclonal/metabolism , Antibodies/metabolism , Antigen-Antibody Reactions , Animals , Immunoglobulin Fab Fragments/metabolism , Insulin Antibodies/metabolism , Models, Biological , Swine , Thermodynamics , alpha-Amylases/immunologyABSTRACT
The effects of electrolytes, chemical modifications of amino groups, and inhibitor binding on the hydration and intrinsic compressibility of lysozyme have been studied using precise ultrasound velocity measurements. The interaction of lithium ions with lysozyme accompanied by cooperative decrease of hydration contribution has been revealed. The neutralization of positively charged amino groups due to their modification is shown not only to decrease the hydration of lysozyme but also to increase its intrinsic compressibility. Binding of tri-N-acetylglycosamine to lysozyme is found to induce the 10-15% decrease in globule intrinsic compressibility. The changes observed in intrinsic compressibility of lysozyme correlate with those of its dynamic properties.
Subject(s)
Muramidase , Ultrasonics , Elasticity , Protein Conformation , Solutions , Substrate Specificity , TrisaccharidesABSTRACT
Ultrasonic velocimetry, a method of molecular biological studies developed in recent years, is an effective tool for investigating hydration of biological substances, conformational transitions of biopolymers and molecular interactions. The method is based upon precise measurements of ultrasonic velocity in solutions of biological substances. The paper presents analysis of the physical bases of the method and possible fields of its applications. Examples of applications of ultrasonic velocimetry to the problems of molecular biology are shown.
Subject(s)
Biopolymers , Macromolecular Substances , Molecular Conformation , Methods , Ultrasonics , ViscosityABSTRACT
Ultrasound of 0,2 Wt/cm2 intensity affects the ionic transport across the mitochondrial membrane in vitro. In the presence of 1 mM EGTA in the incubation medium ultrasound slows down K+ exit into the external medium after the addition of an uncoupling agent (2,4-dinitrophenol). With the addition of 100 divided by 400 mM Ca2+ to the starting medium ultrasound makes the amount of Ca2+ absorbed by mitochondrial decrease and the rate of Ca2+/H+ electroneutral exchange increase. Without Ca2+ ultrasound does not influence the rate of coupled and 2,4-dinitrophenol uncoupled respiration and oxidative phosphorylation, i.e. does not produce strong functional changes.
Subject(s)
Intracellular Membranes/metabolism , Mitochondria, Liver/metabolism , Ultrasonics , 2,4-Dinitrophenol , Animals , Biological Transport, Active/drug effects , Calcium/metabolism , Dinitrophenols/pharmacology , Egtazic Acid/pharmacology , Hydrogen-Ion Concentration , Male , Oxidative Phosphorylation/drug effects , Oxygen Consumption/drug effects , Rats , Rats, Inbred StrainsABSTRACT
The elastic properties of vesicular lipid membranes using high precision ultrasound velocity measurements in egg lecithin bilayer liposomes suspensions were studied. The temperature and K2SO4 concentration dependence of the hydrophobic part of the membrane elastic properties were obtained. The ionic strength dependence is shown to be linear and to change its sign at 27.5 degrees C. The value of molar volume of egg lecithin molecule hydrophobic part as calculated from acoustical and volumetric data is equal to (665 +/- +/- 63) cm3/mol and its adiabatic compressibility is equal to (58.7 +/- 5.9) . 10(-12) cm2/dyne.
