The Journal of experimental medicine
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When cholesterinized antigen is dropped into an excess of water, the rapid flocculation of cholesterin crystals is prevented by the fact that, as tiny aggregates form, they adsorb a protective surface of hydrophilic lecithin (i.e., antigen) which endows the particles with its own stable surface properties and thus prevents further aggregation. The colloidally dispersed antigen-cholesterin particles have approximately the same isoelectric point (pH 1.9), critical potential (1 to 5 millivolts) and coagulation value (0.75 M NaCl) as pure antigen particles of the same concentration, while the corresponding values for cholesterin are pH 2.1 to 3.4 (probably due to an associated impurity), >100 millivolts, and <0.001 N NaCl, respectively. Presumably, this adsorption of antigen by the cholesterin nucleus is determined by the fact that the former has a lower surface tension against water. ⋯ The problem in hand was therefore to find a water-insoluble substance, very soluble in alcohol, with so high an interfacial tension against water that, as in the case of cholesterin, microscopic particles would adsorb antigen when the alcoholic solution of the two is dropped into water. Given such a substance, it would be possible to obtain a more sensitive antigen for both complement fixation and flocculation, but particularly for the former. These theoretical expectations have been realized in a group of substances shortly to be reported: they make possible an antigen which is from 2 to 10 times as efficient in the Wassermann test as any now available.
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A study is reported of the effect of different methods of treatment on the toxemia of cardiac obstruction. The average duration of life of untreated dogs is 3 days. Three dogs treated with 1 per cent salt solution subcutaneously lived 32, 36, and 45 days respectively without developing a toxemia. 2 per cent glucose similarly given, does not alter the course of the toxemia. ⋯ Release of the obstruction does not change the course of the toxemia in untreated animals. The subcutaneous injection of 1 per cent sodium chloride solution after release of the obstruction causes a rapid return of the blood to normal and allows the animal to recover. A similar amount of fluid given as 2 per cent glucose does not alter the course of the toxemia after release of the obstruction.
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It will be seen at once that the mean values obtained for calcium are higher than most of those recorded in the literature, and that the values for inorganic phosphorus are perhaps lower. It is well to bear in mind, however, that the significance that may be attached to any series of determinations of calcium and inorganic phosphorus in the blood of animals depends largely upon the conditions under which the determinations are made. As is well known, there are many factors that may affect the values obtained, including inherent differences in the animal material and the method of analysis used as well as the particular procedure employed in carrying out a given method. ⋯ Moreover, all groups show a large standard deviation and correspondingly high coefficients of variation, but combining the results for the 4 groups of animals gives a fairly uniform and symmetrical distribution, a striking feature of which is the high frequency with which values occur over the entire range of standard variation, that is, from ratios of 2.85 to 4.29. It thus appears that, despite the evidence of a tendency to the observance of an inverse relation between the calcium and inorganic phosphorus in the blood, the ratio of one substance to the other is by no means constant. By using the product and the sum as a basis of expressing the relation between calcium and inorganic phosphorus, the form of the relation is ???
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The results of thirteen control experiments, designed to show the number of glomeruli in the rabbit's kidney open to the circulation under the chosen experimental conditions without intentional interference, indicate the "normal" range to be from 42 to 100 per cent. Since ten of the thirteen results fall within the figures 56 and 89 per cent, we may take these figures as the chief basis for our discussion. Three experiments only were made in which renal vasodilatation was produced by caffeine and salt. ⋯ Thus a relatively uniform constriction was produced in all of such degree as to lessen materially glomerular pressure and blood flow, but insufficient to actually close more than a few afferent arterioles. In Experiment 33, the dosage of adrenalin was such as to permit the possibility that constrictor action may have been largely confined to efferent vessels (8). While the exceptional results have been discussed at greater length than has been devoted to the majority of experiments, we believe that they do not constitute adequate ground for criticism of the chief conclusion as stated.
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1. A technique for determining the respiratory response to carbon dioxide on the Peabody principle is described. 2. ⋯ The respiratory response to carbon dioxide as expressed by the total pulmonary ventilation is slightly greater at high oxygen percentages (90 per cent +/-) than at normal oxygen percentages in the inspired air. 4. Respiratory fatigue may consist of two elements-one nervous, manifesting itself in increased excitability of the center and a more marked response when the demand for pulmonary ventilation is small, the other muscular and involving an inability to respond when the demand for pulmonary ventilation is great.