bluuebunny/crossref_metadata_2025_split huggingface dataset:
THE RATE OF LOSS OF POTASSIUM FROM HUMAN RED CELLS IN SYSTEMS TO WHICH LYSINS HAVE NOT BEEN ADDED
Authors: Ponder Eric 
Published: May 2004

Curves describing the loss of K from human red cells as a function of time can be interpreted in terms of an equation which treats the K content of the cell (φ) as the result of an accumulation process occurring at a rate P and an outward diffusion process regulated by a constant a. The equation is useful for describing the observations and for exploring the mechanisms which may be responsible for the K losses, although it cannot be used for analyzing the experimental data in a strict sense in the absence of independent metabolic data because P and a may both be functions of time. The applicability of the equation is illustrated by its use in connection with experimental curves showing K loss as a function of time at 4°, 25°, and 37°C. for systems containing human red cells in isotonic NaCl or NaCl-buffer.
At 4°C., the K loss follows an exponential curve approaching an asymptote in the neighborhood of φ = 0.50 ± 0.15. The corresponding value of P implies that the cells are able to accumulate about 0.6 per cent of their initial K per hour under these conditions.
At 25°C., the K loss starts exponentially but becomes roughly linear with time after 24 to 48 hours. The change of form is probably due to the appearance of autolysins in the system. Curves of a similar mixed or intermediate form may be obtained even at 4°C. if the observations are sufficiently extended and if spontaneous hemolysis becomes appreciable.
At 37°C., the K loss is exponential for the first 24 to 36 hours, the curves approaching asymptotes which, translated into terms of P, indicate that the cells can accumulate about 7 ± 3 per cent of their initial K per hour. After this time autolysis begins to affect the shape of the curves, the rate of K loss increasing rapidly.
The effect of adding fluoride or iodoacetate is to lower the position of the asymptote to which the curves proceed; i.e., to decrease the accumulation rate P, to increase the diffusion constant a, or both. Cyanide has almost no effect. Hypotonicity has little effect on the rate of K loss at 37°C.; at 4°C., the rate of loss is somewhat less in hypotonic NaCl.
The observation that the K loss in systems at 4°C. and containing as much as 0.086 M NaF does not become complete, but proceeds exponentially towards an asymptote between φ = 0.2 and 0.4, suggests that 20 to 40 per cent of the cell K is much less diffusible than the remainder at low temperatures and in the absence of lytic substances. A similar conclusion is suggested by the form of the curve for K loss into saline at 4°C., an accumulation rate of 0.6 m. eq./litre of cells/hour at the end of 100 hours or more being improbably great for a system at such a low temperature and containing no added glucose.
PHAGE FORMATION IN STAPHYLOCOCCUS MUSCAE CULTURES
Authors: Price Winston H. 
Published: May 2004

1. In the synthetic medium of Fildes contaming hydrolyzed casein virus release is not correlated with observable cellular lysis under conditions of a very low multiple infection.
2. In cells with a high multiple infection, lysis occurs much sooner than in cells with a low multiple infection and virus release is correlated with cellular lysis. The experiments indicate that it is the virus particle itself which accelerates lysis under these conditions.
3. A non-dialyzable fraction has been isolated from yeast, the addition of which results in cellular lysis occurring at a sooner than usual interval and being correlated with virus release in cells having a very low multiple infection.
4. By varying the concentration of the yeast fraction, it is possible to lyse the cells at varying times under conditions of a low multiple infection.
THE STATE OF THE CHROMOSOMES IN THE INTERPHASE NUCLEUS
Authors: Ris Hans , Mirsky A. E. 
Published: May 2004

In the living interphase nucleus no chromosomal structures are visible. Yet in the injured cell and after treatment with most histological fixatives chromatin structures become apparent. Under certain conditions this appearance of structure in the living interphase nucleus is reversible.
We have found that this change in the interphase nucleus is the result of a change in the state of the chromosomes. In the living nucleus the chromosomes are in a greatly extended state, filling the entire nucleus. Upon injury the chromosomes condense and therefore become visible. At the same time the nuclear volume decreases. This behavior of the chromosomes is connected with their content of desoxyribonucleic acid (DNA). This view is based on the following observations:
(a) Distribution of DNA in the Nucleus.—(1) The living interphase nucleus of uninjured cells absorbs diffusely at 2537 Å. No chromosomal structures are visible in ultraviolet photographs unless they are also distinct in ordinary light. If the chromosomes are made to condense they become visible and the absorption at 2537 Å is now localized in these structures. (2) After fixation with formalin and osmic acid interphase nuclei stain diffusely with Feulgen. These fixatives preserve the extended state of the chromosomes. (3) If nuclei are teased out in non-electrolytes (sucrose, glycerin) the chromosomes are extended. Such nuclei stain homogeneously with methyl green. On adding salts the chromosomes condense and the methyl green is now restricted to the visible structures.
(b) Extension and Condensation of Isolated Chromosomes.—When chromosomes isolated from interphase nuclei of calf thymus are suspended in sucrose, their volume is four to five times larger than in saline, but they retain their characteristic shapes. Chromosomes from which DNA and histone have been removed do not show this reversible extension and condensation, neither do lampbrush chromosomes of frog oocytes which contain very little DNA.
During mitosis a partial condensation of the DNA occurs in prophase, so that the mitotic chromosomes now occupy a much smaller volume of the nucleus. At telophase the chromosomes swell again to fill the entire nucleus.
MOVEMENTS OF WATER IN CELLS OF NITELLA
Authors: Osterhout W. J. V. 
Published: May 2004

When one end of a Nitella cell (A) is bathed in water and a solution of sucrose is placed at the other (B) we find that water enters at A, travels along inside the cell, and escapes at B. The solutes which cannot pass out through the protoplasm at B remain behind so that the osmotic pressure increases at B and diminishes at A until equilibrium is reached and the motion stops.
An equation is given which enables us to predict with considerable accuracy the amount of flow required to produce equilibrium.
MUTANTS PRODUCED BY X-IRRADIATION OF SPORES OF CHAETOMIUM GLOBOSUM AND A COMPARISON WITH THOSE PRODUCED BY ULTRAVIOLET IRRADIATION
Authors: Ford J. M. , Kirwan D. P. 
Published: May 2004

1. Mutants produced by x-irradiation of fungal spores of Chaetomium globosum have been compared with those produced by ultraviolet irradiation.
2. The most striking difference between the mutants produced by x-irradiation and ultraviolet irradiation is the absence in x-ray experiments of the K mutant which is produced in large numbers at short ultraviolet wave lengths.
3. A comparison is made of the relation between x-ray dose and numbers of lethal mutants, and the relation between the short ultraviolet wave length 2804 dose and numbers of lethal mutants. Both are compared with theoretical curves for 1, 2, 5, and 8 quantum hits.
4. The production of lethal mutants by x-rays is shown to be consistent with the theoretical curve for five quantum hits on the sensitive spot of the spore, whereas the production of lethal mutants by the ultraviolet wave length 2804 Å.u. is consistent with two quantum hits.
THE INFLUENCE OF HYDROSTATIC PRESSURE AND URETHANE ON THE THERMAL INACTIVATION OF BACTERIOPHAGE
Authors: Foster Ruth A. C. , Johnson Frank H. , Miller Virginia K. 
Published: May 2004

In Difco nutrient broth, containing 0.5 per cent NaCl, pH 6.6, Escherichia coli phages T1, T2, and T5 were inactivated at 66°C., and T7 at 60°C., at nearly the same rate. In each case the rate of destruction was not uniform but more or less decreased with time of heating. With T2 there was an initial increase in number of infective centers after heating for several minutes at 66°C.
Hydrostatic pressures up to 10,000 pounds per square inch retarded the thermal destruction of T1, T2, and T5, but accelerated that of T7, while small concentrations of urethane accelerated the rate of each.
The rate of inactivation was increased by the addition of 0.005 M phosphate, and was decreased by 0.005 M MgCl2 in all but T7, whose rate was unaffected by this amount of Mg. The influence of Ca was similar to that of Mg.
The addition of 0.005 M MgCl2 to the broth medium resulted in a first order rate of destruction of T5 at either normal or increased pressure, and with as well as without urethane. Analysis of data obtained under these conditions indicated that the thermal inactivation proceeds with a volume increase of activation of 113 cc. per mol, and with a heat and entropy of 170,000 calories and 425 E. U., respectively, in the rate-limiting reaction. In the presence of 0.1 M urethane the heat and volume change of activation are apparently slightly greater. The relation between concentration of urethane and the amount of acceleration in rate of destruction at normal pressure and 66°C. indicated that the total rate involves at least two first order rate processes: the thermal inactivation itself and a urethane-catalyzed reaction, the latter involving the combination of an average of 2.3 molecules of urethane in the activated state of the bacteriophage molecule whose destruction results in loss of phage activity.
ELECTRICAL PHENOMENA IN NERVE
Authors: Shanes Abraham M. 
Published: May 2004

The action of a number of agents, which may be classified as "stabilizers" and "unstabilizers" on the electrical oscillations and after-potentials in the squid giant axon has been examined. The effects on the spike, "positive overshoot," and "potassium potential" were also observed, but where possible concentrations were employed which left these phenomena unaltered.
Veratrine augmented the oscillations and the negative after-potential, particularly with repetitive stimulation. Yohimbine caused a small long lasting positive after-potential and depressed the oscillations, effects also enhanced with repetitive activity. Cocaine and procaine suppressed the oscillations and the negative after-potential but DDT was completely inert. An elevation in the medium calcium depressed the oscillations and the naturally occurring negative after-potential; negative after-potentials induced with veratrine were increased by calcium. A decrease in the potassium augmented the oscillations and the negative after-potential.
A hypothesis is presented in which these effects are interpreted in terms of potassium concentration at the fiber surface as regulated by a labile permeability and metabolism. This is discussed in relation to the available evidence for these factors.
It is a pleasure to acknowledge the author's indebtedness to Dr. D. E. S. Brown, Director, and to his staff at the Bermuda Biological Station for Research for the cooperation and special facilities provided during the initiation of this work. Dr. T. Baylor of Princeton University very kindly provided the camera and film used in Bermuda.
ELECTRICAL PHENOMENA IN NERVE
Authors: Shanes Abraham M. 
Published: May 2004

The resting and action potentials of the leg nerves of the spider crab are reduced by procaine, cocaine, iodoacetate, KCl, and veratrine. The first three agents depress the sensitivity of the resting potential to anoxia, while the last can be shown to augment it. Glucose sustains activity and the polarized state in the absence of oxygen, an effect blocked by iodoacetate; corresponding concentrations of lactate and pyruvate are inert under most experimental conditions. DDT and veratrine both induce repetitive activity following an impulse, but only the latter does so with a marked increase in negative after-potential.
The negative after-potential induced by veratrine is decreased by KCl relatively more than the spike or the resting potential. Elevation of the calcium content of the medium increases this after-potential. Neither ion appreciably alters the time constant of repolarization. The recovery is more rapid than that obtained following prolonged activity of both veratrinized and unveratrinized nerves. Repolarization following a tetanus is accelerated by an increase in the volume of solution in contact with the fibers; associated with this is an augmentation of the positive after-potential which normally follows a bout of activity. Yohimbine induces a positive after-potential following individual spikes which is depressed by an elevation of the potassium or calcium content of the medium.
These observations are discussed from the standpoint of the available evidence for the involvement of potassium at the surface of the fibers as regulated by a labile permeability and metabolism. The potassium liberated by the action potential, calculated from the polarization changes, agrees closely with an available analytical figure; less direct observations are also found to be consistent with this view.
TONICITY-VOLUME RELATIONS IN PARTIALLY HEMOLYZED HYPOTONIC SYSTEMS
Authors: Ponder Eric 
Published: May 2004

The linear relation between the red cell volume V and the reciprocal of the tonicity T of a hypotonic medium is not the linear one expected on the basis of the van't Hoff-Mariotte law, particularly when a fraction p of the cells are hemolyzed and the volume V/(1 – p) of the (1 – p) cells which remain intact is considered. In systems of relatively high tonicity in which p is zero, the relation is linear but its slope is usually too small; at lower tonicities in which p has a value between zero and 0.35, the volumes are larger than those expected on the basis of the van't Hoff-Mariotte law, while at still smaller tonicities they are much smaller than expected. The volume measurements referred to are made with a high speed hematocrit; the results obtained in systems containing relatively high and relatively low volume concentrations of cells are contrasted with each other, and allowance is made in the calculations for the volume of the hypotonic medium surrounding the cells being limited.
Attempts are made at an explanation of the anomalous results in terms of incomplete packing, of a stepwise as opposed to an all-or-none loss of Hb from the cells, of a heterogeneity in the swelling properties of the cells of the population, of a loss of osmotically active substances from the intact cells, and of the red cell ghost having some degree of rigidity. These explanations are not satisfying, although some of them in combination may account for the phenomena observed. It seems likely that the structures involved in the hemolytic process (cells and ghosts) have different properties in different tonicity ranges and even when the same tonicity is established in systems which are dense, as opposed to dilute, with respect to cell concentration.
The form of the tonicity-volume relation can be changed substantially, although not in the direction of greater linearity, by treating the cells with resorcinol, colloidal silicic acid, iodoacetate, or sodium oxalate. Small changes in pH, exposure to temperatures as high as 37°C., allowing the cells to stand for periods up to 24 hours, or the substitution of hypotonic plasma for hypotonic NaCl-buffer, produce, on the other hand, only minor changes in the tonicity-volume relation.
THE LOSS OF POTASSIUM FROM FROG NERVES IN ANOXIA AND OTHER CONDITIONS
Authors: Fenn Wallace O. , Gerschman Rebeca 
Published: May 2004

1. Frog nerves immersed in Ringer's solution lose on the average 23 per cent more potassium if the solution is equilibrated with pure nitrogen than if equilibrated with oxygen.
2. Tying off the ends of the nerves during immersion increased rather than diminished the loss of potassium.
3. There was some evidence that nerves tended to regain potassium if they were returned to oxygen after a period of anoxia.
4. Addition of acetylcholine to the solution increases the loss of potassium.
5. Equilibration of the solution and nerves with 20 per cent CO2 in O2 increases the loss of K from nerves in Ringer's solution but decreases it in frog blood.
THE ULTRAVIOLET LIGHT AND PHOTOSENSITIZED INACTIVATION OF TOBACCO MOSAIC VIRUS
Authors: Oster Gerald , McLaren A. Douglas 
Published: May 2004

The quantum yield for the inactivation of tobacco mosaic virus has been determined at 253.7 mµ and found to be 4.3 x 10–6. The possible significance of the observed one-hit process of inactivation has been discussed in terms of the kinetics and the rupture of model substances including nucleic acid. The ultraviolet light inactivation, which proceeds independent of oxygen, occurs without change in physicochemical properties, with the possible exception of an enhanced sensitivity to thermal denaturation.
The photosensitized inactivation of virus by acriflavine has been found to proceed parallel with the destruction of the dye. The action was found to be dependent upon adsorbed dye, and the inactivation is enhanced by the presence of oxygen.
DELAY OF CLEAVAGE OF THE ARBACIA EGG BY ULTRAVIOLET RADIATION
Authors: Blum Harold F. , Price Judith P. 
Published: May 2004

While our data do not permit us to state the exact locus or mode of action of ultraviolet radiation in the Arbacia egg, certain general conclusions may be reached. The amount of delay of cleavage of these eggs is determined by two principal factors: (1) The extent of an effect, resulting from photochemical action induced by ultraviolet radiation, which is reversible in a biological sense, the reversibility not being directly dependent upon the process of cell division. (2) The sensitivity of the cell division process to the effects of the ultraviolet-induced photochemical reaction. This factor varies with the stage of cell division, the cell being insensitive during a period corresponding to most of mitosis.
It seems likely that these findings may apply to cell division in general, but, since the quantitative relationships observed must, in this case, reflect the integration of two semi-independent factors, the over-all picture may appear quite different for different kinds of cells.
TISSUE CULTURE STUDIES
Authors: Hull Wayne , Kirk Paul L. 
Published: May 2004

An improved procedure for measuring the uptake of tracer P32 by tissues in culture is described. It consisted of counting the ß-emissions through a specially designed roller tube in which the culture medium could be effectively removed from the system without opening or damaging the cultures.
In standard growth-promoting medium, the uptake was shown to be markedly greater than in Tyrode's solution. The uptake curve was found to be essentially parallel with the uptake of P32 in desoxyribo- and ribonucleic acids when standard medium was used, and in desoxyrihonucleic acid when Tyrode's solution was used. This is interpreted to signify that the total uptake of tracer phosphorus approximates the growth in the culture.
The value of uptake measurements as a frame of reference for comparison of various types of media and of metabolic studies is indicated.
EFFECTS OF ELECTRICAL CURRENTS ON THE ABSORPTION OF WATER BY EGGS OF NEREIS LIMBATA
Authors: Osterhout W. J. V. 
Published: May 2004

Unfertilized eggs of the marine worm Nereis limbata subjected to electrical currents (direct or alternating) undergo remarkable changes. Certain minute granules just inside the surface of the egg absorb water and swell to more than 300 times their original size and thereby produce a mass of jelly which surrounds the egg with a zone about as wide as the original diameter of the egg. The amount of direct current is too small to produce any change of color in eggs stained with neutral red.
In direct current the jelly appears first on the side toward the anode and moves toward the anode. In alternating current it appears on opposite sides facing the electrodes.
It might be thought that the current changes the chemical character of the granules so that they are able to absorb very large quantities of water but this seems unlikely.
If the current is shut off after 1 minute the swelling continues. This might be explained on the ground that each jelly precursor granule is covered with a waterproof film which is removed by the current.
It does not seem probable that the effect is due to heat produced by the current since the exposure is so short. It seems possible that the current may strip off micelles from the waterproof covering of the granules and allow water to penetrate.
The fact that alternating current is more effective than direct current might be explained on the ground that the egg may be represented as a capacity in parallel with a resistance so constituted that relatively little direct current can enter.
The non-aqueous film which covers the surface of the protoplasm appears to be liquid rather than solid.
PURINE AND PYRIMIDINE CONTENTS OF SOME DESOXYPENTOSE NUCLEIC ACIDS
Authors: Daly M. M. , Allfrey V. G. , Mirsky A. E. 
Published: May 2004

The distribution of purines and pyrimidines in desoxypentose nucleic acids prepared from a variety of animal and plant sources has been studied.
1. The nucleic acids were prepared from calf thymus, calf kidney, sheep spleen, horse spleen, chicken erythrocyte, turtle erythrocyte, trout sperm, shad testes, sea urchin sperm, wheat germ, and Pneumococcus Type III.
2. Separate hydrolyses were carried out for the determination of purines and pyrimidines. These procedures permitted nearly quantitative recovery of nucleic acid phosphorus in many of the preparations examined.
3. In the case of those preparations where a quantitative recovery was obtained it can be concluded that no bases other than adenine, guanine, thymine, and cytosine were present in appreciable amounts.
4. The distribution of purines and pyrimidines in all the nucleic acids studied renders the tetranucleotide hypothesis untenable.
5. The results of the analyses have indicated no great differences in the composition of these nucleic acids with respect to purines and pyrimidines.
THE INTRINSIC VISCOSITY OF MIXED PROTEIN SYSTEMS, INCLUDING STUDIES OF PLASMA AND SERUM
Authors: Hess Eugene L. , Cobure Aspascia 
Published: May 2004

Experimental evidence is presented that the intrinsic viscosity of solutions of mixed proteins obeys the additive equation
See PDF for Equation.
The datum serves to characterize the system, and combined with other analytical techniques and fractionation procedures, enables one to analyze and characterize subfractions. The plasmas and sera of clinically "normal" individuals give intrinsic viscosity values agreeing with calculated values. The intrinsic viscosity values for pathological plasmas and sera in all cases are greater than normal and reflect the augmented levels of those proteins fibrinogen, α2-globulins, and γ-globulins occurring in the pathological state. The method is readily adaptable to routine clinical use and furnishes a measure of the departure from normal of protein levels in serum and plasma.