bluuebunny/crossref_metadata_2025_split huggingface dataset:
“Red” and “Green” Receptors in the Retina of Tropidonotus
Authors: GRANIT RAGNAR 
Published: December 2008

Summary.Micro‐electrode, amplifier and cathode ray oscillograph have been used for the recording of “spikes” from restricted units in the retina of anaesthetized snakes in response to monochromatic light of known energy content. The problem has been to study the distribution of sensitivity to monochromatic light of more or less restricted discharges in this cone eye.There is a broad dominator band of sensitivity with maximum in 0.560 μ, similar to the dominator found in the frog's eye.There are further two narrow modulator bands of sensitivity with maxima in respectively 0.600 and 0.520 μ.The “red” modulator is sometimes obtained in the practically isolated state but generally the “green” modulator appears coupled to it so that a secondary hump of variable size is found with maximum in 0.520 μ.
On the Amount of Reticulocyte Ripening Substances in the Plasma of Various Adult Mammals.
Authors: PLUM CLAUS MUNK 
Published: December 2008

Summary.The amount of ripening substances in plasma is considerably reduced when whole blood is stored. The reduction seems to be larger, the more reticulocytes were found in the blood sample. When the blood clots about frac12; of the ripening substances disappear.When plasma is stored only a slight decrease in the quantity of ripening substances occurs. Plasma incubated for 24 hours at 4° remains practically unchanged.The quantity of ripening substances in the plasma of various mammals shows a certain correlation between the number of reticulocytes in the circulating blood and the concentration of the substances that determine the ripening of the reticulocytes, so that a high percentage of reticulocytes goes with a low ripening index and vice versa. This applies both from individual to individual and from species to species. In blood in which no reticulocytes are found there is the highest concentration of ripening substances. This being the case with oxen I chose to their plasma as the unit for the concentration of ripening substances.
Reticulocyte Ripening Substances in Plasma in Animals with Increased Erythropoiesis.
Authors: PLUM CLAUS MUNK 
Published: December 2008

Summary.The quantity of ripening substances in young rats is large at birth and afterwards decreases with the fall in the number of reticulocytes in percentage of erythrocytes, and when figure sare reached that accord with those found in mature rats, the rest of the blood picture also resembles that in mature rats.During chronic hemorrhagic anemia a rise in the number of reticulocytes may be seen in rabbits. The reticulocytes do not change in character as regards the time they take to ripen when they are subjected to the same concentration of ripening substances, but on the other hand an increase in the quantity of ripening substances in plasma is found in anemized rabbits. This increase shows that under the conditions here described the reticulocytes in the vascular system must ripen about 20 ‐ 30 % more rapidly than those in normal rabbits.In the two cases investigated an increased erythropoiesis then is followed by an increased amount of reticulocytes ripening substances in the plasma.
A Note on the Preparation of Renin and the Appearance of a Heat‐Stable Pressor Substance in Renin Solutions.
Authors: EULER U. S. v. , SJÖSTRAND T. 
Published: December 2008

Summary.A convenient method for the preparation of renin from pig's kidney is described.Purification of crude renin preparations has been accomplished by fractionate precipitation with acetone or by adsorption to kaolin.A dialysable, heat‐stable pressor substance may appear spontaneously in dialyzed renin solutions. The new substance has not the properties of hypertensin (angiotonin).
Is the Citric Acid Metabolism Affected by Ether Anaesthesia?
Authors: MÅRTENSSON JOHAN 
Published: December 2008

Summary.A series of experiiiients on rabbits has shown that1) Ether anaesthesia does not alter the citric‐acid content of the blood serum (Ci/s) in a nephrectomized animal. just as little as it does in a normal animal;2) Ci‐elimination in a nephrectomized animal proceeds with the same intensity both before and after an ether anaesthesia;3) After nephrectomy without anaesthesia the Ci/s rises, as it also does after nephrectomy under anaesthesia;4) After nephrectomy without anaesthesia the elimination of administered Ci is considerably slowed up as compared with the elimination before the nephrectcmy.The experiments show that the anaesthesia administered in the Writer's earlier animal experiments did not influence the results of the investigation, which have accordingly been confirmed.
The Spectral Properties of the Visual Receptors of the Cat
Authors: GRANIT RAGNAR 
Published: December 2008

Summary.The micro‐electrode technique has been used for the recording of spikes of activity from the retina of the cat in order to study the distribution of sensitivity to spectral light of the retinal elements.In dark‐adapted cats the distribution of sensitivity corresponds to the absorption curve for visual purple.In light‐adapted cats some elements give the broad so‐called photopic dominator band with maximum in 0.560 μ, others a narrow curve with maximum in 0.520 μ combined with the dominator in different ratios.The narrow curve is probably identical with the band seen in the eyes of rats and guinea pigs corresponding to an abnormally narrow absorption curve for visual purple, in the cat shifted somewhat to the right because of the added effect of the dominator.Some results indicate that back reflexion from the tapetum lucidurn plays a ro1e in determining the shape of the curves in the yellow‐green region of the spectrum.The colour vision of the cat has been, discussed in the light of the results arrived at.
Rate of Formation of Nucleic Acid in the Organs of the Rat.
Authors: HEVESY G. , OTTESEN J. 
Published: December 2008

Summary.Labelled phosphate is administered to adult rats by subcutaneous injection. After the lapse of 4 days, the rats are killed and the desoxyribose nucleic acid present in different organs is extracted. By comparing the activity of 1 mg desoxyribose nucleic acid P with the activity of I mg cellular inorganic P of the same organ, data on the percentage renewal of the desoxyribose nucleic acid present in the organs are obtained.In the course of 4 days, only a minor part of the desoxyribose nucleic acid present in all the organs investigated is found to be labelled, i. e. renewed. The greatest daily renewal of nucleic acid (15 per cent) takes place in the mucosa of the small intestine. This is followed by the spleen (5.8 per cent), the testes (2.6 per cent), the muscles (1.9 per cent), and the liver (1.0 percent). The lowest figures are shown by the kidneys and the brain (0.6 per cent).
Propagation of Contraction in the Isolated Striated Muscle Fibre.
Authors: BUCHTHAL FRITZ , KNAPPEIS G. G. 
Published: December 2008

Summary.The propagation of contraction over the isolated muscle fibre is measured by the changes in the cross striation, i. e. shortening of the anisotropic (A) and lengthening of the isotropic (I) substance being used as indicator. Simultaneous microcinematography (100 Pictures/sec.) of two points of the isometrically placed fibre shows a phase difference in the course of the changes in cross striation, which corresponds to a propagation rate of 0.32 m/sec ±±0.016 (20° C). The change in the cross striation is transmitted through the fibre without decrement. Dependent on the distance between point of measurement and point of stimulation, an increase in height of compartment is found so long as the contraction has not reached the fibre elements under observation.The rate of propagation of contraction is essentially lower than that of the spread of action potential (excitation potential). The influence of propagation velocity on the course of the mechanical tension developed, and on the latent period, are discussed.
The Determination of Ascorbie Acid in Biological Fluids
Authors: REHBERG P. BRANDT 
Published: December 2008

Summary.Various redox‐indicators have been tried in determinations of ascorbic acid.Dichloroindophenole seems to be best suited for electrophotometric determinations.A simple but improved electrophotometer is described.Methods for the determination of ascorbic acid in various biological fluids are described. In the serum the determination may be carried out without protein precipitation.In urine substances are present, which contrary to the general conception interfere most in the more acid buffersThe best results are obtained with buffers of a pH around 4.5.
The Nature of the Amino Nitrogen of Red Corpuscles
Authors: USSING HANS H. 
Published: December 2008

Summary.The permeability of red corpuscles to amino acids is examined. It is shown that monarnino monocarbonic acids diffuse until an even partition is reached in the two water phases. This process takes less than 24 hours at 37°. The dicarbonic acids: glutaniic acid and aspartic acid are diffusing extremely slowly through the corpuscle membrane. It is demonstrated that monoamino monocarbonic acids are present in about the same concentration in the corpuscles and the plasma.The origin of the high amino‐N content of the corpuscles compared with the plasma is investigated and it is found that nearly all the excess amino‐N came from glutathione so that the concentration of true amino acids is equally high in the water phases of corpuscles and plasma.
Antithrombin Content of the Blood in Peptone Intoxication of Rabbits.
Authors: VOLKERT MOGENS 
Published: December 2008

Summary.1. Experimental studies are reported on the tolerance and reaction of rabbits to intravenous injection of Witte peptone, and it is illustrated that shock can be produced also in rabbits if only the peptone is injected in sufficient amount.2. The antithrombin content of rabbit blood is examined after injection of varying amounts of peptone. It is pointed out that, when shock is produced, it is possible also in rabbits to elicit an increased formation of heparin‐like substances in the blood. In addition, it is demonstrated that administration of smaller amounts of peptone may give a decrease in the antithrombin content of the blood. These findings are discussed.
The Reticulocyte‐Ripening Index after Loading with Liver Extract and Tyrosine
Authors: PLUM CLAUS MUNK , PLUM RUTH 
Published: December 2008

Summary.After injections of liver extract in rabbits, an increase in reticulocyte‐ripening substances in plasma is found. In the first 24 hours after the injection the ripening substances in plasma can be activated with tyrosine in contrast to normal plasma and are therefore taken to be the unaltered liver substances.Injections of tyrosine alone in the same quantities as found in the liver extract used, also produced an increase, but exclusively of fully activated ripening substances. Controls with saline give no rise.
Microdetermination by Electrolysis of the Sum of Inorganic Cations in Biological Fluids.
Authors: HOLM‐JENSEN IB. 
Published: December 2008

Summary.A brief survey of the principles of electrolytic determinations of cations of alkali metals and of metals of the alkaline earths is given and a modification of the method of Adair and Keys for microestimation of the sum of cations in unashed samples of biological fluids is presented.
On the Effect of some Coumarin and Dicoumarin Derivatives on the Prothrombin Level in Babbits.
Authors: LEHMANN JÖRGEN. 
Published: December 2008

Summary.

The prothrombin depressing effect of derivatives of coumarin and 3,3'‐methylene‐bis‐(4‐hydroxycoumarin) have been investigated in rabbits in order to find the pharmacologically active groups and if possible a watersoluble stable compound of the dicoumarin.
Most of the substances tested were found active. The highest activity—combined with less toxicity—was excerted by 3,3'‐methylene‐bis‐(4‐hydroxycoumarin).
Carboxymethylene‐bis‐(4‐hydroxycoumarin) was water‐soluble but of very little activity.
The active groups in the dicoumarin are discussed. Introduction of certain radicales in the hydroxygroups as well as in the methylene bridge did not abolish the activity whereas this was the case when other radicales were introduced at the same places.
Oxidatire Breakdown of Hyaluronic and Chondroitin Sulphuric Acid.
Authors: SKANSE BENGT. , SUNDBLAD LARS. 
Published: December 2008

Summary.

The viscosity of hyaluronic acid solutions is markedly reduced by ascorbic acid in the presence of atmospheric oxygen. Cu++ highly increases this effect, which is on the other hand completely inhibited by diethyldithiocarbamate, or cyanide. Catalase does not inhibite the action of ascorbic acid.
Dehydroascorbic acid obtained by oxidation of ascorbic acid with molecular oxygen + Cu++ has, under aerobic conditions, the same effect as ascorbic acid + Cu++.
The effect of ascorbic acid is also greatly increased by hydrogen peroxide, which itself although relatively slowly, reduces the viscosity of hyaluronic acid solutions. In the presence of hydrogen peroxide the ascorbic acid is also active anaerobically. The mechanism of the action of ascorbic acid is discussed.
A viscosity decreasing effect is brought about also by molecular oxygen (at + 100° C), potassium permanganate, and, in the presence of atmospheric oxygen, by hydroquinone, pyrogallol and cysteine + Cu++. The effect of oxygen is inhibited by diethyl‐dithiocarbamate and cyanide.
The products formed from hyaluronic acid during its oxidative breakdown are non‐reducing and dialysable. The decrease of the viscosity is accompanied by the disappearance of the double refraction of flow shown by the native hyaluronic acid solution.
The oxidative depolymerisation of hyaluronic acid is connected with the formation of titratable acid groups in an amount approximately corresponding to one carboxylic group for each disaccharide unit of glucuronic acid and N‐acetylglucosamine.
Determinations of glucosamine and glucuronic acid in the solution of the dissociated products suggest that the main reaction product might be a “disaccharide” of glucuronic acid and N‐acetylglucosaminic acid.
Chondroitin sulphuric acid is broken down in the same way as hyaluronic acid by ascorbic acid and hydrogen peroxide. The reaction is, however, slower and does not proceed as far as that of hyaluronic acid under the experimental conditions employed.
Heparin, starch and cellulose could be similarly broken down to some extent by ascorbic acid.
On the Effect of Local Stimulation by Cold on the Adrenaline Secretion.
Authors: EKSTRÖM TORE. , LUNDGREN NILS. , SCHMITERLÖW CARL G. 
Published: December 2008

Summary.

The adrenaline secretion following on local cold‐stimulation of the skin has been studied in the rabbit. As an indication of increased adrenaline secretion, the increase in width of a sympathetically denervated pupil, sensitized by cocaine, was employed.
In animals with intact innervation of the skin the adrenaline secretion showed an increase during the cold‐stimulation, even if body temperature was kept constant. This effect was not produced after previous section of the spinal cord or after lumbar anaesthesia.
In animals in which the innervation to the cold‐stimulated skin area had been cut off, no demonstrable increase in the adrenaline secretion appeared in response to the stimulation. The effect of the cold‐stimulation on the adrenaline secretion is thus reflex in kind.
Even a considerable fall in general body temperature did not in itself provoke any detectable reflex liberation of adrenaline.
On the Glucosidases of the Intestine of the Pig.
Authors: STEENSHOLT GUNNAR. , VEIBEL STIG. 
Published: December 2008

Summary.An investigation is made of the glucosidases of the small intestine and the duodenum of the pig. It is shown that both α‐and β‐glucosidase occur, and the pH‐activity curves of both enzymes are determined.
Some Chemical Properties of the Gastric Secretory Excitant from the Pyloric Mucosa
Authors: UVNÄS BÖRJE 
Published: December 2008

Summary.The gastric‐secretory excitant from the pyloric mucosa shows the following chemical porperties:—It is soluble in water. The solubility varies with the pH.It is insoluble in ether, acetone, benzene, and absolute and 80% ethyl alcohol.It is stable in weak acid and alkaline solutions. It resists heating in N/10 HCl at 100° C. but is destroyed when heated in N/10 NaOH to this temperature.It is inactivated by pepsin, trypsin (duodenal juice), and ultraviolet light.It dialyses through cellophane.It is precipitated by trichloracetic acid, metaphosphoric acid, NaCl, and acetone.
Humoral or Nervous Control of Respiration during Muscular Work?
Authors: ASMUSSEN ERLING , CHRISTENSEN E. HOHWÜ , NIELSEN MARIUS 
Published: December 2008

Summary.The pulmonary ventilation and the oxygen intake during light to moderate work on the bicycle ergometer were determined under normal conditions and in experiments in which the circulation to the lower extremities was interrupted by means of pneumatic cuffs. The experiments showed, that although the oxygen intake could by this procedure be diminished by 20–50 pCt., the ventilation remained almost unchanged.From these experiments it is concluded, that the increase in the excitability of the respiratory centre towards CO2, which occurs during work cannot be ascribed to substances produced in the working muscles, but must be of nervous origin.
CO2‐breathing and Output of the Heart
Authors: ASMUSSEN ERLING 
Published: December 2008

Summary.On two subjects it is shown, that hyperventilation, caused by CO2‐breathing, has an increasing effect on the cardiac output if the subject lies horizontally, none, however, if the subject is tilted to an upright (60°) position. It is concluded, that the effect of CO2‐breathing on the cardiac output must be due to the mechanical forces of hyperventilation and not to a chemical action of the CO2 on the circulation, as otherwise the difference of the effect in the two positions is unexplained.By increasing the inspiratory or exspiratory resistance artificially the negativity of the intra‐pleural pressure could be increased, respectively decreased. It was found that this had very slight and irregular effects on the cardiac output, and it is concluded, that the augmented negativity of the intra‐pleural pressure during hyperventilation cannot be the cause of the increased cardiac output.It is discussed how the deep respirations of the hyperventilation might influence the cardiac output, and the conclusion is put forward tentatively, that this is possible if one assumes that the enlarged respiratory movements cause a pressing‐out of blood from the intra‐pulmonary (or, and from the abdominal) vessels, when these are “filled” with blood (as in the horizontal position), not, however, when they are “empty” (as in the tilted position). The conclusion is supported by experiments, in which part of the blood was shut off in the legs.
The Exchange of Ions between Cells and Extracellular Fluid: The Uptake of Potassium into the Chorion Membrane from the Hen's Egg
Authors: KROGH AUGUST 
Published: December 2008

Summary.The fact that living cells both in animals and plants are generally permeable both to kations and anions makes it necessary to investigate the mechanisms by which the large differences in concentration of single ions inside and outside cells are maintained.As a consequence of the general and free permeability for water the osmotic pressures inside and outside animal cells must be identical, and this involves the presence of at least a large fraction of the ions in the free state, because no other substances are available to reach such high concentrations.Methods are described to study the transfer of ions between cells and extracellular fluid in isolated chorion membranes from the hens egg, to prepare ultrafiltrates from these membranes and to distribute the ions determined on cells and extracellular solution.The chorion membranes are made up of two layers of epithelium and a loose network of primitive connective tissue cells with large extracellular spaces. Approximate measurements of numbers and dimensions of the separate cell types are presented.It is found that prolonged washing with potassium free Tyrode solution will reduce the K+ content of the cells to about half the normal (50 millimoles), the K+ being replaced by Na+, while K+ will be absorbed by the cells from the outside solution containing at the start 15 to 3 mM K+ down to concentrations of 1 millimole or less, raising the concentration of the ultrafiltrate from the cells above 100 millimoles. Simultaneously Na+ is removed from the cells against the outside concentration of about 150 mM.The two ions together with the undetermined anions make up a very large fraction of the total osmotic pressure of the solution in each cell.The active transfer of ions in both directions requires energy which appears to be provided mainly by non oxidative breakdown of carbohydrate and can go on at least for some time in the absence of free oxygen.At low temperature (3°–7°) the active transfer is reduced or abolished and the diffusion tends to equalize the concentration of each ion across the protoplasmic boundary film.It is pointed out in the discussion that specific structures and mechanisms involving a binding of the ions of elements in the boundary film must be assumed to account for the active transfer. The mosaic membrane model proposed by Lundegårdh is discussed and it is shown that the “points” responsible for potassium uptake are probably spaced at comparatively large distances apart.The possible mechanisms for regulating the transfer are briefly discussed.
Über eine durch Kohlenoxydhehandlung hervorgerufene qualitative Veränderung des Stoffwechsels im Froschsartorius
Authors: LINDAHL P. E. , WERNSTEDT CHR. 
Published: December 2008

Zusammenfassung.In Sartorius‐Muskeln von Eana temporaria, die über Nacht in Ringerlösung bei 0 Grad geschüttelt worden sind, ist RQ gleich 0.72 ± 0.017. Eine etwa einstündige Behandlung mit 20% O2 + 80% CO bewirkt nach Überführung in CO‐freies Medium eine Erhöhung des RQ auf 0.99 ± 0.028. Diese Veränderung kann nicht auf eine Milchsäurebildung während der Behandlung zurückgeführt werden (Tab. 2). Der der Veränderung des RQ zu Grunde liegende Mechanismus wird diskutiert.
The Physiological Variations in the Reaction of the Human Urine
Authors: RYBERG CARL TH. 
Published: December 2008

Summary.The physiological variations in the pH of the human urine have been investigated under fixed experimental conditions. The occurence of morning alkaline tides and postprandial alkaline tides has been confirmed, and in addition it has been shown that a meal may cause a transient excretion of a urine with an increased acidity before the alkaline tide begins.
Eine Antriebsvorrichtung für Laboratoriums‐gebrauch—in Verbindung mit einem Präzisionsinjektionsapparat
Authors: LINDGREN GUNNAR 
Published: December 2008

Zusammenfassung.Es wixd eine Vorrichtung für Permanentinfusion beschrieben; dieselbe gestattet kontinuerliches Variieren der Injektionsge‐schwindigkeit zwischen 1 und 3 125—ohne Auswechseln der Spritze. Die Apparatur kann auseinandergenommen werden und der Motor mit dem Zahnradsystem für sich gebraucht werden und an verschiedene Laboratoriumsapparate gekuppelt werden.