SWELLING — increase in volume of a solid owing to absorption by it from the environment of liquid or steam. In medicine understand increase in volume of cells or a stroma of internals as N.
Ability to N. is idiosyncrasy of the bodies formed by high-molecular substances (polymers). In N it is caused by diffusion processes, to-rye usually are followed solvation (see). Distinguish N. limited and unlimited. In the first case of a macromolecule are connected rather strongly and N. stops, having reached a certain limit; at the same time the bulked-up body keeps a form and a clear boundary of the section with fluid medium. In the second case interdiffusion of solvent and a polymeric body gradually leads to disappearance of limit of the section between the bulking-up body and liquid; The N comes to the end with full dissolution of polymer.
The N is followed by calorification, emergence of pressure reaching sometimes hundreds and even thousands of kgfs! cm2. N.'s degree is determined by a volumetric gain or the mass of polymer and expressed as a percentage or in grams of the liquid absorbed by gram of polymer. The volume of the bulked-up gel can exceed own volume of polymer in tens of times. Polar polymers usually bulk up in polar solvents, unpolar — in unpolar. N.'s degree increases at temperature increase, at shifts of pH from a pzoelektrichesky point. N. is influenced by the nature of ions of solvent, usually according to a lyotropic series.
The N of cells can result from disturbance of a water salt metabolism p excess binding of water a cell (an overhydratation of the cellular water sector) that is observed, e.g., as a result of a delay in an organism of sodium at depression of function of kidneys. The similar pathogeny has gidropi-chesky N. of an epithelium of gyrose tubules of kidneys during the use of osmotically active agents like Mannitolum, urea, hypertensive solutions of glucose, etc. The delay of liquid in a nefroteliya is explained at the same time by increase in osmolarity of cytoplasm due to fixing in it diuretic substances. Such N. of cells is essentially functional and is quickly liquidated at alignment of water-salt balance of an organism or cancellation of diuretics. More difficult mechanisms are the cornerstone of N. of substance of the brain arising at heavy endo-and ekzotoksikoza of various etiology. However and there is an excess binding of water colloids of cytoplasm of neurocytes, glial cells and nerve fibrils of white matter.
The gross appearance of swelling of body is most brightly expressed during the swelling of a brain. The brain at the same time is increased in volume, flabby, a surface of cuts dry, in vessels the condensed blood is visible. The destruction of neurocytes and nerve fibrils progressing hypoxemic character can be similar N.'s outcome that is promoted also by the vklineniye of a brainstem which is quite often complicating this process in a big occipital opening. A bit different character has N. of cells and fibrous substances at parenchymatous and mesenchymal proteinaceous dystrophies — a dis-proteinosis (see. Proteinaceous dystrophy ). So, at the granular dystrophy most often developing in a liver, a myocardium and kidneys increase in body in sizes, flabbiness, dimness of a parenchyma on a section is noted. Therefore in such cases speak about muddy N. of bodies.
The special kind of N. of intercellular substance is observed at collagenic diseases (see). At the same time distinguish the Mucoid and fibrinoid N. of connecting fabric caused by various depth of its disorganization. At mucoid N. (see. Mucous dystrophy ), developing most often in walls of arteries, valves of heart, an endocardium and an epicardium, raised a basophilia also the metachromasia of the main substance of connecting fabric due to accumulation of hromotropny substances microscopically is defined. During the progressing of process there can occur irreversible disorganization of connecting fabric — the fibrinoid N. which is coming to an end with a fibrinoid necrosis (see. Fibrinoid transformation ). Process is followed by homogenization of collagenic fibers owing to treatment by their proteins of plasma and fibrin; fibers are intensively painted by acid dyes, sharply CHIC-are positive, pironino-filna and argentofilna.
A wedge, N.'s manifestations depend on body, it develops in Krom. The N of a brain is shown by coma. Muddy N. of parenchymatous bodies is expressed in decrease in their function. In one cases of N. of cells and fabrics — process reversible, not demanding special methods of therapy, in others — leads to death of cells and fabrics.
Bibliography:Voyutsky S. S . Course of colloid chemistry, page 442, M., 1975; P and with y N - sky A. G. Colloid chemistry, page 179, M., 1968; N. K. Residents of Perm. Bases of resuscitation pathology, M., 1979; Strukov A. I. iserovv.v. Pathological anatomy, page 27, M., 1979.
N. K. Permyakov; V. O. Shpikiter (biochemical).