The normal and pathological movement of water in tissues and its relation to the colligative properties of solutions and to inflammation.
A series of studies, each suggested by those that preceded, were first concerned with the movement of water in parenchymatous cells of liver, kidney, submaxillary glands, and other glandular organs. Evidenee was soon obtained showing that these cells were isotonic as determined by the osmotic pressure they maintained, not with physiological salt solution (0.15 M), as at that time popularly assumed, but with sodium chloride in approximately twice this concentration. Cells of the liver or of the kidney acted as osmometers and measured the osmotic pressure which they maintained. When various eleetrolytes were tested, it was found that their osmotic pressures varied with the valence of the basic ions of the salts that were used, being, for example; I for monovalent sodium salts, 2 for calcium salt, 3 for lanthanum salts. Solutions of the salts of eleetrolytes manifest properties so bound together that they are designated colligative. These properties include osmotic pressure, depression of the freezing point, vapor tension, and boiling point of solutions. It is well established that any one of them provides data from which the others can be dedueed by appropriate calculation.1 The changes which oceurred in liver or in kidney were found to be in aecord with tables which record changes in the freezing point of graded solutions of salts of electrolytes, on the one hand, or of boiling points on the other. Visible necrosis of the skin of laboratory animals was produeed by injeetion into the dermis, and the molar strength of solutions of various electrolytes needed to cause it was determined. This varied with the valence of the basic ions of the salts that were tested and followed a sequence which was the same as that of the isotonicity of liver or of kidney cortex immersed in corresponding solutions. The molar concentration of amino acids that produced necrosis followed the same order as osmotic pressure of liver in the same solutions. The relation of necrosis to the colligative properties of electrolytes suggested a study of the relation of inflammatory reactions to the moleeular constitution of agents that cause them. Injection of injurious substances into the large serous cavities of the body, peritoneal and pleural, offered a method by which exudation of fluid, leucocytes, and plasma protein could be measured with considerable accuracy. The numerical results thus obtained give an adequate measure of the inflammatory reactions. The relations cited emphasize the dependence of normal and pathological changes upon the colligative properties of electrolytes and of organic compounds which direet the movement of water and of the compounds it may contain. With these relations in mind, it has seemed desirable to review the sequence of studies which were undertaken to measure the movement of water in cells and interstitial tissue under normal and under pathological conditions.
THE EFFECT OF INJURY BY TOXIC AGENTS UPON OSMOTIC PRESSURE MAINTAINED BY CELLS OF LIVER AND OF KIDNEY
As shown in a previous paper the cells of the liver and of the kidney maintain an osmotic pressure approximately twice that of blood and of erythrocytes, exceeding this slightly in the case of liver and being slightly less in that of kidney. When liver cells are injured by chloroform or by carbon tetrachloride the osmotic pressure they maintain falls to the level of the medium that surrounds them but is promptly restored when recovery from the injury, with some regeneration of liver cells, occurs. When nephrosis is caused by potassium chromate or by chloroform the osmotic pressure maintained by parenchymatous cells of the renal cortex falls to that of the medium about them but returns to its normal level with recovery from the injury.
Photoreflectance characterization of vanadium-doped GaAs layers grown by metalorganic vapor phase epitaxy
Abstract We characterized the vanadium-doped (GaAs:V) layers grown on GaAs substrate by metalorganic vapor phase epitaxy. The conductivity of the samples is checked by the Hall effect measurements, and it is n type with electrons concentration ranging from 2×10 13 to 2×10 17  cm −3 . We used the photoreflectance technique (PR) to study the effect of vanadium doping on the optical properties of GaAs. Our experimental results show that the built-in electric field F and the broadening parameter Γ 0 increase with V-doping concentration. Furthermore, the temperature dependence of the built-in electric field and the broadening parameter of GaAs:V samples have been investigated by PR. It has been observed that these parameters increase with increasing temperature. The decrease of the built-in electric field with decreasing temperature is due to the photovoltage effect.We characterized the vanadium-doped GaAs (GaAs:V) layers grown on GaAs substrate by metalorganic vapor phase epitaxy.