bluuebunny/crossref_metadata_2025_split huggingface dataset:
STUDIES ON BLOOD COAGULATION
Authors: Eagle Harry 
Published: May 2004

Although calcium is essential for the formation of thrombin, it can be recovered quantitatively from formed horse thrombin without affecting its coagulating activity. Citrate also has no significant effect. As stated in the text, this does not exclude the possibility that thrombin is actually a calcium compound present in minute concentration; but confirming the results of Hammarsten, it does show that fibrin cannot be a calcium-protein compound unless one assumes molecular weights for fibrinogen greater than 1,000,000.
Although the available experimental data concerning the properties of thrombin, the kinetics of its reaction with fibrinogen, and the quantitative relationships between the two do not allow a definite decision as to whether thrombin is an enzyme analogous to rennin, or whether it combines with fibrinogen to form an insoluble compound, fibrin, the weight of evidence does favor the enzyme theory. A given quantity of thrombin can form at least 200 times its weight of fibrin, and in view of the crudeness of the preparation this ratio is probably many times greater. There is no apparent stoichiometric relationship between thrombin and fibrinogen, and thrombin does not disappear from a mixture of the two until the moment of coagulation; the quantity which then disappears is many times the minimal quantity necessary to form the amount of fibrin produced.
STUDIES ON THE ELIMINATION OF DYES IN THE GASTRIC AND PANCREATIC SECRETIONS, AND INFERENCES THEREFROM CONCERNING THE MECHANISMS OF SECRETION OF ACID AND BASE
Authors: Ingraham Raymond C. , Visscher Maurice B. 
Published: May 2004

1. All dyes appearing in gastric juice after intravenous injection in the dog are characterized by having their chromogen in the electropositive ion under suitable conditions.
2. All dyes eliminated in pancreatic juice ionize with the chromogen electronegative under proper circumstances.
3. The amphoteric characteristics of certain dyestuffs, as well as the changes in charge associated with reversible reduction in others, have been taken into consideration, and the lack of success of previous investigators in finding a common characteristic of dyes secreted by the gastric glands differentiating them from those secreted by the pancreas, has been shown to have been due to failure to take these potentialities of the dyestuffs into account.
4. Several possible hypotheses concerning the mechanism of selectivity to dyestuffs have been considered. Differences in distribution in acid, neutral, and alkaline phases will not account for selective secretion without postulating also specific membrane permeability. It is pointed out that the theory most thoroughly in accord with all the facts observed is based upon the pore concept. To restrain electronegative dyes by polar adsorption, the pores of the membranes of the gastric glands would have to be positively charged. Such pores would constitute an electrostatic filter, restraining from passage all mobile ions of the same charge. The anions, which in plasma are mostly chloride, could pass this barrier into the secretion. In order to have hydrochloric acid formation, anion exchange would have to occur, bicarbonate, lactate, or some other anion from the gland lumen returning to balance chloride entering, leaving the hydrogen ion from the weaker acid in the secretion. This tentative theory can also be seen to fit many of the facts of pancreatic secretion, where electropositive dyes are restrained, and alkali is secreted.
CORRELATION OF OXIDATION AND PHOSPHORYLATION IN HEMOLYZED BLOOD IN PRESENCE OF METHYLENE BLUE AND PYOCYANINE
Authors: Runnström John , Michaelis Leonor 
Published: May 2004

1. The system:hemolyzed blood + glucose never exhibits glycolysis or, in the air, oxidation of glucose. When glucose is replaced by hexosephosphate ester, addition of methylene blue causes oxidation in air.
2. When cozymase is added also, the oxidation is increased, and a synthesis of hexosephosphate esters takes place.
3. When pyocyanine is used instead of methylene blue, the rate of oxidation is the same as with methylene blue, but a synthesis of phosphate esters takes place without addition of cozymase.
4. There is never a phosphate ester synthesis without oxidation going on, but oxidation does not necessarily go hand in hand with phosphate synthesis.
5. In order to couple the oxidation process with phosphate synthesis, two methods are available: either to start oxidation by methylene blue and to add coenzyme from yeast cells; or to start oxidation by pyocyanine, in which case coenzyme is unnecessary, though it improves the effect.
6. Iodoacetate always suppresses synthesis, but only under certain conditions decreases oxidation. Cyanide has no effect upon either process.
RELATION BETWEEN BIRTH WEIGHT AND LITTER SIZE IN MULTIPAROUS MAMMALS
Authors: Enzmann E. V. , Crozier W. J. 
Published: May 2004

In multiparous mammals there is a definite relation between the litter size N and the total weight of the litter W. Reasons are given showing that this relationship is independent of the mechanism of parturition.
For various forms W = NK + const. Hence the average increment of W due to unit increase of N is directly proportional to W, inversely to N. This signifies proportionality between N and nutritive drain upon the mother, as well as equipartition among the members of the litter. K is non-specific, and is therefore regarded as a partition index.
THE SOLUBILITIES, APPARENT DISSOCIATION CONSTANTS, AND THERMODYNAMIC DATA OF THE DIHALOGENATED TYROSINE COMPOUNDS
Authors: Winnek Philip S. , Schmidt Carl L. A. 
Published: May 2004

1. The solubilities and differential heats of solution of d-tyrosine, dl-tyrosine, diiodo-dl-tyrosine, dibromo-l-tyrosine (hydrated), dibromo-l-tyrosine (anhydrous), and dichloro-l-tyrosine (hydrated) have been determined.
2. Evidence has been advanced that dl-tyrosine is a compound.
3. From the solubility determinations at various acidities, the apparent acid and basic dissociation constants of dibromo-l-tyrosine and dichloro-l-tyrosine have been determined at 25° and 40°C. From these data the apparent heats of ionization have been calculated.
4. The question concerning which of the groups in l-tyrosine and its dihalogenated substitution products is responsible for each dissociation constant has been discussed.
THE ELECTRICAL ACTIVATION OF PASSIVE IRON WIRES IN NITRIC ACID
Authors: Lillie Ralph S. 
Published: May 2004

1. The relation between the E. M. F. and the minimal duration of an activating current has been determined for passive iron wires in nitric acid under varying conditions of concentration of acid, duration of recovery period, and presence of surface-action compounds.
2. The characteristic intensity-duration curves resemble those of irritable living tissues with moderate speeds of response to stimulation (with chronaxies of the order of 10 to 30σ).
3. The intensity of the current required for activation, as well as its minimal effective duration for a given intensity, increases rapidly with increase in the concentration of HNO3.
4. The responsiveness of the iron wire to brief currents is low immediately after activation and returns progressively to the original level during the immediately following period, at first rapidly and then slowly, following a time curve resembling the corresponding curve of living tissues during the relative refractory period.
5. Surface-active compounds decrease reversibly, to a degree dependent on concentration, the responsiveness of iron wires to brief currents.
6. Conditions are described under which the iron wire is activated by the break of an already flowing constant current.
THE EFFECT OF X-RAYS ON CHROMOSOMES IN DIFFERENT STAGES OF MEIOSIS
Authors: Marshak A. 
Published: May 2004

1. Pollen mother cells exposed to low dosages of x-rays at various stages show different frequencies of chromosome abnormalities in the first meiotic anaphase.
2. Maximum frequencies of abnormalities were obtained in buds irradiated in the pachytene stage of the meiotic prophase and in the preceding mitosis.
3. These results are taken to indicate that the x-ray-sensitive portions of the chromonemata are closely approximated in pairs in pachytene and in the early mitotic prophase. The significance of this in relation to non-homologous pairing is indicated.
4. From the nature of the chromosome configurations observed it is concluded that chromonemata are two-parted when they synapse and that a chromonematic division occurs between pachytene and anaphase and during the mitotic prophase.
5. The frequencies of abnormalities show a linear relationship to dosage.
6. The diameter of the sensitive volume of the chromonema is calculated and found to approximate the diameter of some known protein molecules.
7. The linkage mechanism is found to make up about 90 per cent of the total sensitive volume which corresponds with the approximate reduction in length of the chromonema from pachytene to anaphase.
8. The relation of these sensitive volumes to the gene is discussed.
ACTION POTENTIALS IN THE NERVOUS SYSTEM OF THE CRAYFISH
Authors: Prosser C. Ladd 
Published: May 2004

Increase in temperature elicits an increase in the number of nerve impulses arising spontaneously from deafferented crayfish ganglia. This alteration in gross frequency gives an apparent temperature characteristic of 27,000 calories.
Changes in the number of active fibers and in the frequency of discharge of individual units account for the alterations in the gross frequency. The change in number of active units gives a n value of 17,500 calories.
Individual fibers fall into two groups with respect to the effect of temperature on their frequency of discharge. One of these groups exhibits a µ value of 14,500 calories and the other yields a µ value of 7,000 calories.
ADAPTATION OF CUTANEOUS TACTILE RECEPTORS. III
Authors: Hoagland Hudson 
Published: May 2004

Further experimental evidence is presented indicating that the peripheral inhibitory phenomenon known as sensory adaptation, as it is manifested in tactile receptors in frogs' skin, is produced by a neurohumor released by non-nervous cells of the skin when they are pressed upon.
1. Adaptation is not produced by electrically initiated antidromic impulses backfired into the axon branches.
2. Intermittent air jet stimulation of a region of skin several millimeters distant from a responsive single ending produces failure of response of the ending to a similar direct intermittent stimulus applied to the skin containing the ending immediately afterward.
3. Constant pressure causes an ending to adapt but no spread of the effect, as described in the above paragraph, is found. This implies that the spread is the result of the vibratory movement of the skin.
4. The time curves of recovery from adaptation are inconsistent with any known properties of isolated nerve.
THE DARK ADAPTATION OF RETINAL FIELDS OF DIFFERENT SIZE AND LOCATION
Authors: Hecht Selig , Haig Charles , Wald George 
Published: May 2004

The decrease in threshold shown by the eye during dark adaptation proceeds in two steps. The first is rapid, short in duration, and small in extent. The second is slow, prolonged, and large. The first is probably due to cone function; the second to rod function.
In centrally located fields the two parts of adaptation change differently with area. With small, foveal fields the first part dominates and only traces of the second part appear. As the area increases the first part changes a little, while the second part covers an increasing range of intensities and appears sooner in time.
Measurements with an annulus field covering only the circumference of a 20° circle show most of the characteristics of a 20° whole field centrally located. Similarly a 2° field located at different distances from the center shows dark adaptation characteristics essentially like those of large centrally located fields whose edges correspond to the position of the central field.
Evidently the behavior in dark adaptation of centrally located fields of different size is determined in the main not by area as area, but by the fact that the retina gradually changes in sensitivity from center to periphery, and therefore the larger the field the farther it reaches into peripheral regions of permanently greater sensibility.
RELATION OF OXYGEN TENSION AND TEMPERATURE TO THE TIME OF REDUCTION OF CYTOCHROME
Authors: Stier T. J. B. 
Published: May 2004

The time for the appearance of the cytochrome C absorption band after shaking a suspension of bakers' yeast with various O2-N2 mixtures was determined at each of six temperatures. At each temperature a linear relation between this interval—called the reduction time—and O2 tension was found. It was shown:
1. That under our experimental conditions, absorption bands of cytochrome were seen when the O2 tension of the suspension was reduced to, or below, a certain pressure which was found to be specific for each temperature (this pressure is provisionally considered to be identical with or very near to the "critical O2 tension" usually found in QOO2-O2-tension relationships);
2. That the x-axis intercept obtained from the reduction time - O2-tension plot gives the value of the "critical" O2 pressure at each temperature;
3. That the O2 tension within the suspension is reduced by the respiratory activity of the yeast cells.
An equation describing these observations is given and is used in calculating rates of O2 consumption from measurements of reduction time of cytochrome. The average difference between the calculated values and the manometric measurements of QOO2 was found to be 6.6 per cent. A rapid optical method of measuring rates of O2 consumption based on the findings of these experiments is proposed for use with cytochrome-containing microorganisms.
CAROTENOIDS AND THE VISUAL CYCLE
Authors: Wald George 
Published: May 2004

1. Carotenoids have been identified and their quantities measured in the eyes of several frog species. The combined pigment epithelium and choroid layer of an R. pipiens or esculenta eye contain about 1γ of xanthophyll and about 4γ of vitamin A. During light adaptation the xanthophyll content falls 10 to 20 per cent.
2. Light adapted retinas contain about 0.2–0.3 γ of vitamin A alone.
3. Dark adapted retinas contain only a trace of vitamin A. The destruction of their visual purple with chloroform liberates a hitherto undescribed carotenoid, retinene. The bleaching of visual purple to visual yellow by light also liberates retinene. Free retinene is removed from the isolated retina by two thermal processes: reversion to visual purple and decomposition to colorless products, including vitamin A. This is the source of the vitamin A of the light adapted retina.
4. Isolated retinas which have been bleached and allowed to fade completely contain several times as much vitamin A as retinas from light adapted animals. The visual purple system therefore expends vitamin A and is dependent upon the diet for its replacement.
5. Visual purple behaves as a conjugated protein in which retinene is the prosthetic group.
6. Vitamin A is the precursor of visual purple as well as the product of its decomposition. The visual processes therefore constitute a cycle.
THE IMMUNOLOGICAL SPECIFICITY OF THE EUGLOBULIN AND PSEUDOGLOBULIN FRACTIONS OF HORSE AND H^MAN SERUM
Authors: Harris Tzvee , Eagle Harry 
Published: May 2004

That portion of horse and human serum globulin precipitated by 33 per cent saturation with ammonium sulfate and precipitated on subsequent dialysis was taken as euglobulin; and the fraction precipitated between 33 and 50 per cent saturation and remaining in solution on subsequent dialysis was taken as pseudoglobulin.
The sera of rabbits injected with either of these antigens gave precipitation with both. However, two distinct and fraction-specific antibodies could be demonstrated by absorbing the sera with the one antigen, and testing the supernatant fluid with the other. The experimental results are adequately explained on the basis that there are at least two antigenically distinct globulins in serum which we may term globulin I and globulin II and which are largely associated with so called euglobulin and pseudoglobulin respectively. The ordinary methods of salting out and dialysis do not effect complete separation and each globulin preparation contains a trace of the other antigen. The antisera to these euglobulin and pseudoglobulin preparations therefore contain antibodies to both antigens. Each protein solution precipitates all the antibody specific for the one antigen and in addition, by virtue of the trace of contaminating protein, precipitates a portion, and only a portion of the antibody specific for the other antigen.
The fact that antisera to whole serum contain these same fraction-specific antibodies suggests that this immunological specificity is an inherent property of two globulins present as such in serum and is not an artifact induced by their precipitation and purification.
Lipoids extracted from the globulins by ether, petroleum ether, and alcohol give no demonstrable reaction with antisera to these globulins; antisera absorbed with a large excess of lipoid are not affected as regards their reactivity with the original protein; and globulins extracted with ether and petroleum ether at room temperature are not affected as regards their reactivity with antisera. It is concluded that the immunological specificity of the globulin fractions as evidenced by the precipitation reaction is not determined by lipoids associated with the protein.
SULFHYDRYL AND DISULFIDE GROUPS OF PROTEINS
Authors: Mirsky A. E. , Anson M. L. 
Published: May 2004

Hemoglobin and the proteins of the crystalline lens contain active SH groups while in the native state, the number of active groups increasing as the pH rises. All the SH groups of denatured globin and of the denatured lens proteins are active at a pH so low that practically none of the SH groups of native hemoglobin and of native lens protein are active. The effect of denaturation on the SH groups of a protein is to extend towards the acid side the pH range of their activity.
It is possible to oxidize the iron-porphyrin and the SH groups of hemoglobin independently of each other.
THE REDUCING GROUPS OF PROTEINS
Authors: Mirsky A. E. , Anson M. L. 
Published: May 2004

1. Intact, unhydrolyzed proteins possess in addition to SH groups other reducing groups which can be oxidized by ferricyanide.
2. The activity of these reducing groups, like that of SH groups, is enhanced by denaturation of the protein and by increase of pH and temperature.
3. These groups differ from SH groups in the manner in which their activity is dependent on concentration of ferricyanide and time of contact with ferricyanide.
4. The activity of these groups is increased if protein SH groups are present.
5. The number and activity of these groups varies from protein to protein.
6. These groups are probably contained in the tyrosine and tryptophane components of proteins.
7. The significance of these reducing groups for an understanding of protein denaturation and the reducing properties of tissues is indicated.
THE METABOLIC SYSTEMS INVOLVED IN DISSIMILATION OF CARBOHYDRATE RESERVES IN BAKERS' YEAST
Authors: Stier T. J. B. , Stannard J. N. 
Published: May 2004

Evidence is presented showing that the dissimilation of carbohydrate reserves in two strains of bakers' yeast, Saccharomyces cerevisiae, is a purely respiratory process.
Endogenous respiration is KCN-labile. Our own experiments together with various accounts and data given in the literature show that the same "oxygen-transporting mechanism" functions in both endogenous and exogenous metabolism. However, the lack of sensitivity of the endogenous system of reactions to low concentrations of monoiodoacetic acid, the absence of anaerobic CO2 production, and the absence of alcohol production, demonstrate that fermentation is not involved in the dissimilation of the carbohydrate reserves.
Throughout the experiments the endogenous respiration behaved functionally as a unitary system of reactions. The O2 consumption and CO2 production were parallel at all times; i.e., the R. Q. was consistently 1. Monoiodoacetic acid and KCN in concentrations from 10–5 to 10–1 molar affected both O2 uptake and CO2 production to the same extent. The only agents known to alter the value of the R. Q. were those which disrupted the normal protoplasmic structure, viz. grinding the cells with sand, plasmolyzing them with toluol and hypertonic salt solutions, or pressing them in a hydraulic press. These agents brought about a vigorous anaerobic CO2 production accompanied by an accumulation of alcohol in the medium.
The unitary character of endogenous respiration is exhibited only when the normal structure of the cell is kept intact; apparently it depends upon the maintenance of a chambered (or compartmental) architecture of the cell.
ON THE VARIABILITY OF CRITICAL ILLUMINATION FOR FLICKER FUSION AND INTENSITY DISCRIMINATION
Authors: Crozier W. J. 
Published: May 2004

From the data of experiments with bees in which threshold response is employed as a means of recognizing visual discrimination between stripes of equal width alternately illuminated by intensities I1 and I2, it is shown that the detectable increment of intensity ΔI, where ΔI = I2 - I1, is directly proportional to σI2 (I1 being fixed). From tests of visual acuity, where I1 = 0 and the width of the stripes is varied, σI2 = kI2 + const.; here I2 = ΔI, and ΔI/I2 = 1. When the visual excitability of the bee is changed by dark adaptation, λI ≡ kΔI (= k' σΔI) = k'' I + const. For the measurements of critical illumination at threshold response to flicker, σI2 (= σΔI) = k I2 = k' ΔI + const.
The data for critical illumination producing threshold response to flicker in the sun-fish Lepomis show for the rods σI2 = K I2 for the cones σI2 = K'(I2 + const.).
The data thus indicate that in all these experiments essentially the same visual function is being examined, and that the recognition of the production of a difference in effect by alternately illuminated stripes takes place in such a way that d (ΔI)/d (σI2) = const., and that ΔI is directly proportional to I (or "I2," depending on the nature of the experiment).
It is pointed out that the curve for each of the cases considered can be gotten equally well if mean I or σI is plotted as a function of the independent variable involved in the experiment.
Certain consequences of these and related facts are important for the treatment of the general problem of intensity discrimination.
THE CHANGE IN STATE OF THE PROTEINS OF MUSCLE IN RIGOR
Authors: Mirsky A. E. 
Published: May 2004

1. When myosin is exposed to a typical denaturing agent (acid) it becomes insoluble and its SH groups are activated.
2. The same number of active SH groups is found in the soluble myosin of resting muscle as in the insoluble myosin of muscle in rigor. No activation of SH groups accompanies the formation of insoluble protein in rigor.
3. When the insoluble myosin of muscle in rigor is treated with a denaturing agent its SH groups are activated.
4. Protein coagulation as brought about by denaturing agents (heat, acid, alkali, alcohol, urea, salicylate, surface forces, ultraviolet light) is a distinctly different change from the coagulation of myosin brought about by the unknown agent in muscle.