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.
OSMOTIC ACTIVITY OF TISSUES DURING FETAL AND POSTNATAL GROWTH
The osmotic pressure maintained by liver tissue of the white rat preceding birth is less than that of the maternal blood serum and shortly after birth approximates this level. Following birth osmotic pressure of liver tissue, continuing to increase, reaches after about 60 to 90 days the level found in the liver of mature animals and is then isotonic with solutions of sodium chloride with concentration slightly more than twice that isotonic with blood serum. Osmotic pressure maintained by kidney tissue pursues with growth a similar course but at a lower level and about 35 to 60 days after birth reaches that found in the mature animal being represented by isotonicity with a concentration of sodium chloride slightly less than twice that isotonic with blood serum. The tissues of the whole fetus are isotonic with sodium chloride solutions less concentrated than that isotonic with the maternal blood serum.
Two new organic reference materials for delta13C and delta15N measurements and a new value for the delta13C of NBS 22 oil.
Analytical grade L-glutamic acid is chemically stable and has a C/N mole ratio of 5, which is close to that of many of natural biological materials, such as blood and animal tissue. Two L-glutamic acid reference materials with substantially different 13C and 15N abundances have been prepared for use as organic reference materials for C and N isotopic measurements. USGS40 is analytical grade L-glutamic acid and has a delta13C value of -26.24 per thousand relative to VPDB and a delta15N value of -4.52 per thousand relative to N2 in air. USGS41 was prepared by dissolving analytical grade L-glutamic acid with L-glutamic acid enriched in 13C and 15N. USGS41 has a delta13C value of +37.76 per thousand and a delta15N value of +47.57 per thousand. The delta13C and delta15N values of both materials were measured against the international reference materials NBS 19 calcium carbonate (delta13C=+1.95 per thousand ), L-SVEC lithium carbonate (delta13C=-46.48 per thousand ), IAEA-N-1 ammonium sulfate (delta15N=0.43 per thousand ), and USGS32 potassium nitrate (delta15N=180 per thousand ) by on-line combustion continuous-flow and off-line dual-inlet isotope-ratio mass spectrometry. Both USGS40 and USGS41 are isotopically homogeneous; reproducibility of delta13C is better than 0.13 per thousand, and that of delta15N is better than 0.13 per thousand in 100-microg amounts. These two isotopic reference materials can be used for (i) calibrating local laboratory reference materials, and (ii) quantifying drift with time, mass-dependent fractionations, and isotope-ratio-scale contraction in the isotopic analysis of various biological materials. Isotopic results presented in this paper yield a delta13C value for NBS 22 oil of -29.91 per thousand, in contrast to the commonly accepted value of -29.78 per thousand for which off-line blank corrections probably have not been quantified satisfactorily.