bluuebunny/crossref_metadata_2025_split huggingface dataset:
Colour Receptors of the Frog's Retina
Authors: GRANIT RAGNAR 
Published: December 2008

Summary.Spikes have been recorded with micro‐electrodes, amplifier and cathode ray oscillograph from the retinae of light‐adapted frogs and during dark‐adaptation.The chief aim of this work has been to collect a large number of curves showing the distribution of sensitivity to spectral light of single or a restricted number of elements.Most elements have a distribution of sensitivity which coincides with the average curve with its maximum in 0.560 μ and legs extending over a relatively large part of the spectrum (see fig‐ 9).But there are also narrow bands of sensitivity with maxima ranging between 0.450–0.600 μ. The maxima of these bands are chiefly gathered around 0.580–0.600 μ, 0.520–0.540 μ, and 0.450–0.470 μ. Curves from the last mentioned group are rare.Curves illustrating dark‐adaptation (or recovery of sensitivity) for different wave‐lengths are given in the paper and compared with visual purple regeneration.The blue‐sensitive elements recover at a faster rate than others after light‐adaptation and in this way can also be isolated from the region around 0.500 μ occupied by the absorption band of visual purple.The kind of mechanism of colour reception that might be expected from such a system is briefly discussed, and it is suggested that in many respects it may be very like that of man.
Untersuchimgen iifoer die periphere Blut‐versorgung des Herzmuskels
Authors: ENGSTRAND LARS 
Published: December 2008

Zusammenfassung.

Eine Methode ist ausgearbeitet worden zur möglichst schnellen Fixierung der Blutbahnen im Herzmuskel, die quantitative kapillare Studien möglich macht.
Eine intramurale Durchblutung scheint unter der Systole vor sich zu gehen, docn unter erhohtem Wiederstand, was haupt‐sachlich auf der Kompression der quergehenden kapillaren Ana‐stomosen und Venen beruht.
Bei Variation der Herzfrequenz von 380 zu 820 stellte sich lieraus, dass linearer Zusammenhang zwischen der kapillaren Kontaktflache und dem längsten Diffusionsabstand auf der einen Seite und der Länge der diastolischen Herzphase auf der anderen herrscht.
Azetylcholin in intravenöser Injektion ergab in grosser Dosen mit Frequenzsenkung eine starke Vergrösserung von Ka‐pillarquerschnitt und Kapillaranzahl bei wachen und mit Per‐nokton betäubten Tieren.
Pernokton bewirkt nach subkutaner Inj ektion erst bei tief er Narkose, im Stadium von Eespirations‐ und periphere Zirkulations‐insuffizienz, eine deutliche Dilatation der Herzarterioli und Ka‐pillaren.
On the Action of the Optical Isomers of Adrianol, Corhasil, Sympatol and Ephedrine on Isolated Intestine
Authors: EMILSSON BÖRJE 
Published: December 2008

Summary.

The action of the optical isomers of adrianol, corbasil, sympatol and ephedrine on isolated rabbit's intestine has been studied.
The 1‐isomers of adrianol, corbasil and sympatol inhibit the intestine in all cone, whereas the d‐isomers stimulate the intestine in small doses and inhibit it in larger ones.
The 1‐isomers of adrianol, corbasil and sympatol have a greater inhibiting activity than the d‐isomers. Thus 1‐adrianol is 10 000 times as active as d‐adrianol, 1‐corbasil 200 times as active as d‐corbasil and 1‐sympatol 2 times as active as d‐sym‐patol.
1‐, dl‐ and d‐Ephedrine are equally active on isolated intestine, stimulating it in small doses and inhibiting it in larger ones.
Considering the stimulating effect of d‐adrianol, d‐corbasil and d‐sympatol on the intestine as well as the different ratios between the activities of the isomers on blood pressure respective on isolated intestine, it is concluded that there is a qualitative difference in the mode of action of the optical isomers of the investigated drugs.
Without itself affecting the motility of the intestine d‐adrianol abolishes the inhibiting effect of 1‐adrenaline and 1‐adria‐nol but does not diminish the response to 1‐corbasil.
The theoretical interpretation of the different pharmaco‐dynamical action of enantiomorphic compounds is discussed.
Temporal Sequence of Component Potentials in the Frog's Retina and the Electrotonic Potential in the Optic Nerve
Authors: BERNHARD C. G. 
Published: December 2008

Summary.The temporal sequence of the component potentials Pu and Pni in the retina, the electrotonic potential and the spike activity in the optic nerve has been analyzed for the frog's eye with directly coupled amplifier and oscillograph.The slow potential changes follow in the sequence: P11], Pu, electrotonic potential and spike discharge both at onset and cessation of illumination. Their respective latencies are given for maximal stimuli. A diagram is shown in fig. 5.The electrotonic potential reproduces the properties of Pn. The theoretical significance of this result is being discussed.
Blood Coagulation and Species Specificity of Fibrinogen
Authors: ASTRUP TAGE , DARLING SVEN 
Published: December 2008

The influence of an alteration in pH on the action of thrombin on fibrinogen has been investigated several times. In the present paper this relation is investigated for the fibrinogens of ox, chicken, horse and man.Summary.

The action of thrombin on fibrinogen of various species in relation to pH is investigated.
Fibrinogen shows species specificity.

This work has been aided by grants from «Danmarks tekniske Hojskoles Fond for teknisk Kemi» and from «Lovons kemiske Fabrik», Copenhagen.
Spectral Properties of the Visual Receptor Elements of the Guinea Pig
Authors: GRANIT RAGNAR 
Published: December 2008

Summary.Microelectrode, amplifier and cathode ray have been used for the recording of “spikes” of activity from isolated elements of the retina of the guinea pig in response to monochromatic light of known energy distribution.The average distribution of sensitivity to spectral light of photopic (light‐adapted) and scotopic (dark‐adapted) eyes suggests that visual purple is the main substance mediating sensations in this eye. These curves are given in figs. 2 and 3.Individual units of scotopic retinae follow the absorption curve for visual purple very closely.In the photopic state most units are activated by a narrow sensitivity band with the maximun of visual purple; some units respond to a narrow band with maximum in 0.530 μ. But there are also elements with maximum in the blue region around 0.460 μ. As a rule these units cannot be isolated from those with maximum in 0.500 JX.But assuming the “blue” elements to represent narrow bands of the type given by the “green” ones (maxima in 0.500 and 0.530 p.) the average photopic curve, which possesses a hump in the blue region of the spectrum, can be combined by adding up the three elementary curves in the right proportion. Thus it has become possible to give a complete description of the spectral properties of the photopic elements in the guinea pig's eye.Isolated elements are easily obtained in this eye and their reaction types have been described.The possible relation of the “blue” substance to lactoflavin and “transient orange” has been discussed. Of all retinae hitherto studied this one has the most prominent sensitivity to blue light.The author is indebted to the Rockefeller Foundation for a grant to this laboratory.
After Potentials in Mammalian Voluntary Muscle
Authors: BERNHARD C. G. , EULER U. S. v. 
Published: December 2008

Summary.The spike potential accompanying single isometric twitches in the cat's tibialis anticus muscle elicited by indirect stimulation is followed by a slow potential of negative sign (NAP).The negative after potential, as a rule, rapidly reaches a maximum and then in about a second approaches the resting potential level Repeated stimuli of frequencies of about 5/sec and more give rise to a summed negativity, the magnitude of which depends on the shape of the single NAP and on the frequency and duration of stimulation up to certain limits, persisting for as long as a minute.At the height of the post‐tetanic negativity the single NAP is reduced in amplitude and duration, in inverse proportion to the total negativity. As the total negativity falls after the cessation of the stimuli, the single NAP recovers and reaches its original magnitude when the post‐tetanic negativity has passed.No correlation was found between the degree of potentiation of the post‐tetanic twitch tension and the posttetanic negativity or the single NAP.Potassium chloride injected into the arteries of the muscle caused the NAP to decrease, or disappear, or even to change into a positive potential. In the latter case the usual post‐tetanic negativity was changed into a positive potential. Even in the complete absence of the NAP, the muscle twitch tension and the spike potential may be of normal magnitude.
The Localization of the Adenylic Acids in Striated Muscle‐Fibres
Authors: CASPERSSON T. , THORELL. BO 
Published: December 2008

Summary.Ultra‐violet absorption‐spectra have been measured of individual isotropic and anisotropic segments in striated muscle‐fibres from insects. By means of comparisons with ultra‐violet micro‐photographs it is shown to be probable that the results obtained in this way are applicable to striated musculature in general. The absorption‐curves show that the main part of the adenine derivatives (adenylic acid and adenyl‐pyrophosphoric acid) in the resting muscle are localized in I. These segments seem to have their main function as the seat of chemical energetic processes while A is the seat of the contractile elements. From observations on fatigued muscle‐fibres one deduces that energy is transferred from I to A by adenyl‐pyrophosphate whose energy is released by the phosphatase that is bound to the myosin.The background to the striation of the muscle‐fibres thus seems to be a differentiation of contractile parts and chemically‐working parts respectively. The transport of energy from the latter to the former is performed by adenyl‐pyrophosphoric acid.The work has been supported by funds from the Rockefeller Foundation and the foundation “Thérèse oeh Johan. Anderssons minne.”
Selective Activation of a Transient Reflex by Restricting Stimulation to Certain Frequencies
Authors: BERNHARD C. G. , SKOGLUND. C. R. 
Published: December 2008

Summary.Experiments have been carried out on decerebrate cats with a view to studying the effect of frequency of stimulation upon reflex activity.With frequencies between 50–100 per sec. stimulation of the sciatic nerve activated a late secondary extensor reflex after a latent period of 3–5 sec. This reflex was transient in the sense that it lasted only about 15–30 sec. The optimal frequency, for which this transient reflex was maximal, was 90—100 per sec.The transient extensor contraction was found to be part of a complex general defensor pattern involving extension of all limbs, ventroflexion of the trunk and the tail, wihdrawal of the head, and a number of vegetative components such as micturition, raise of blood pressure (cf. Aschkenaz 1939), and pupil dilatation. The vegetative effects were also observed in animals which had received dial and therefore did not show the motor reactions. The whole defensor reflex pattern was optimally evoked by the frequency optimal for the extensor contraction.The transient extensor reflex turned up bilaterally. When evoked by an ipsilateral stimulus in the midst of a crossed extensor it showed itself as a transitory contraction in the trough of the ipsilateral inhibitory effect. However, it turned up equally well without a background of crossed extension. When elicited by crossed stimulation the transient effect had the shape of a hump on the ordinary crossed extensor reflex, provided that the frequency of the stimulus was sufficiently high.No proprioceptive background was necessary for the transient extensor contraction, as shown by deafferentation.Section of the spinal cord in the lower thoracic region did not abolish the reflex.The transient reflex could be elicited from n. popliteus but not from nn. peroneus, saphenus and glut. sup.
On the Prothrombin Content in Milk
Authors: SCHØNHEYDER FRITZ , THOMSEN. SVEND BAASTRUP 
Published: December 2008

Summary.The milk prothrombin level was studied in cows and human beings. In the months before and directly after calving one can demonstrate considerable amounts of prothrombin in cow's milk. The woman colostrum also contains prothrombin but only in small amounts. At other times in the lactation period the cow's milk and human milk contain only negligible amounts of prothrombin.The prothrombin content in the cow's colostrum is of no importance to the increase of the prothrombin in the blood of the new‐born calf.
Uber eine Depressorsulbstanz, die sich im Serum in vitro bildet
Authors: SJÖBERG KNUT , æRBLOM. ERIC 
Published: December 2008

Zusammenfassung.Bewahrt man steriles Serum von Mensch, Pferd oder Rind einen bis mehrere Tage bei 38° C. auf, so bildet sich eine Substanz, die bei intravenöser Injektion bei der Katze oder beim Kaninchen eine stark blutdruckssenkende Wirkung besitzt. Diese Wirkung ist von Histaminnatur, die Substanz ist aber mit diesem Stoff oder anderen bekannten Depressorsubstanzen nicht identisch. Zur Herbeiführung einer Blutdruckssenkung ist eine gewisse Mindestmenge der betreffenden Substanz erforderlich.Überlebender Meerschweinchendarm wird nicht beeinflusst.Die Wirkung bleibt besteben, wenn das Eiweiss aus dem Serum ausgefällt wird.Die Substanz ist ausser in Wasser auch in Alkohol und Äther löslich.Aktives Serum erträgt eine 30 Min. lange Erhitzung auf 60–65° C., ohne dass die Wirkung beeinträchtigt wird. Gereinigte Präparate sind dagegen temperaturempfindlich.
Determination of the Red Corpuscle Content
Authors: HEVESY G. , ZERAHN. K. 
Published: December 2008

Summary.A simplification of the method of determination of the red corpuscle content (the erythron) previously communicated is described.A blood sample taken from a rabbit is shaken in the thermostat at 37° for about 2 hours in the presence of labelled sodium phosphate and, then, it is reintroduced into the circulation of the rabbit. A comparison of the total labelled phosphorus content (radioactivity) of the corpuscles injected with the total labelled phosphorus content of corpuscle samples secured few minutes after the injection took place leads to the value of the erythron.The corpuscle content of the rabbits investigated varied between 20.5 and 26.5 gm per kg of rabbit weight.The authors wish to express their heartiest thanks to Professor Niels Bohr for numerous facilities kindly put at their disposal.
The Rôle of the Reticulo‐endothelial System in the Ripening of Reticulocytes.
Authors: JACOBSEN ERIK , PLUM CLAUS MUNK 
Published: December 2008

Summary.We briefly describe a method of estimating the amount of reticulocyte ripening principle, present in liver extracts and in plasma.Unlike liver extracts the reticulocyte ripening principle in plasma cannot be further activated by tyrosine. The treatment of plasma with acetone for example transforms the ripening principle into a state in which it can be activated.By means of splenectomy and the intravenous injection of trypan blue we blocked the reticulo‐endothelial system in rabbits.The effect of the blocking was controlled by a modification of the Congo red method, the colour of the plasma being measured in the Pulfrich photometer.After blocking the reticulo‐endothelial system the amount of the ripening principle in plasma first decreases considerably and then increases slowly, following closely the recovery of the reticuloendothelial system. The diminislied quantity of ripening substance can be activated by tyrosine and this obtaining the same effect as before the blocking of the reticulo‐endothelial system. These findings make it seem probable that tyrosine and an unknown substance are linked together in the reticulo‐endothehal system and thus form the reticulocyte ripening principle found in plasma.
Antithormbin and Heparin
Authors: ASTRUP TAGE , DARLING SVEN 
Published: December 2008

Summary.1. The formation of an antithrombic substance from heparin is investigated.2. In accordance with earlier authors the presence of a thermolabile substance in blood plasma is found to be necessary for the formation of an antithrombic substancc from heparin. This substance is called thrombin coinhibitor.3. The thrombin coinhibitor is found to be a more labile substance than hitherto assumed. It is destroyed after heating to 56° for 5 minutes. It is only found in plasma, and is not present in serum, while it is destroyed during the clotting process.4. It is found that the thrombin coinhibitor is not identical with the normal antithrombin of plasma and serum.5. To distinguish between the normal antithrombin and the antithrombic substance formed from heparin the last mentioned substance is called thrombin inhibitor, as the two substances are not identical.6. Thrombin inhibitor is much more stable than the thrombin coinhibitor, and almost as stable as the normal antithrombin.7. While normal antithrombin seems to combine with thrombin to form an undissociable compound, the compound between thrombin inhihitor and thrombin, as well as the compound between heparin and thrombin coinhibitor, seems to be highly dissociable.8. Thrombin is inactivated much more rapidly by thrombin inhibitor than by antithrombin.9. The discrepancies between our results and those of earlier authors are discussed.
Studies on the Conducting Properties of the Human Skin to Direct Current
Authors: ROSENDAL THOMAS 
Published: December 2008

Summary.The resistance to direct current (voltage 0–12 V) of a 7 cm2 skin area on the volar side of the forearm has been determined under different conditions, using polarization‐free silver‐silver chloride electrodes.The skin resistance is almost exclusively located in the stratum corneum and decreases very markedly with increasing electrolyte content of this layer. The conductivity of the stratum germinativum corresponds to that of the internal tissue which is rich in electrolyte, and behaves like a low ohmic resistance to d. c.On 7 cm2 of skin area, the stratum corneum shows polarity to d. c. at currents below 1 mA, since the resistance to anodic conduction increases with increasing e. m. f. up to 2–4 volts, while the resistance to cathodic conduction decreases. At voltages above 2–4 volts, the resistance to both directions of current decreases to a value which corresponds to the resistance of the internal tissue. This decrease in resistance is presumably due to a short‐circuiting of the stratum corneum. The polarity of the stratum corneum, which is highest when voltages around 2 volts are applied, is brought into relation to a possible electric charge of the stratum corneum and to the type and the concentration of the contact electrolyte.The pH of the contact electrolyte (4 cc I per cent KCl‐solution) decreased after standing on the skin for 20–45 min to a mean value of 4,97, determined on 4 persons in 14 experiments. In contradistinction to REIN'S investigations, no change in the pH of the contact electrolyte after anodic and cathodic conduction of d. c. through the skin could be observed.
Muscle Action Potentials during Electric and Chemical Stimulation of the Motor Area of the Cerebral Cortex in the Waking Animal and under Anaesthesia.1
Authors: JUUL AKSEL 
Published: December 2008

Summary.1) We have performed local leading off by means of ADRIAN and BRONK'S concentric needle electrode from the extensors of the forearm of rabbits during direct electric and chemical stimulation of the motor area of the cortex partly in the waking animal and partly under anaesthesia.2) By electrical stimulation of the cortical motor area agreement between the frequency of the muscle action potential and the frequency of the stimulation is only seen when the latter is below 10 cycles.3) In electrical as well as in chemical stimulation of the motor area of the cortex a pronounced after‐activity was found, often persisting for several minutes. This after‐activity is of central origin.4) The frequency of the muscle action potentials varies during electric and chemical stimulation of the cortex between 2–3 per second and c. 80–90 per second. During strychnine action a frequency of up to 125 per second was found.5) Quinine has an inhibitory effect on the muscle action potentials (the motor end‐plate) produced by the action of strychnine on the cortex. Calcium has no effect on the strychnine contractions.6) Picrotoxin acts much the same as strychnine on the motor area of the cortex, while cardiazol in a 10 % solution has only a very slight central effect.
Calcium metabolism and citric acid
Authors: NICOLAYSEN RAGNAR , NORDBØ RAGNVALD 
Published: December 2008

Summary.Injections of citric acid will not cure rickets in rats. Ca subnourishment depresses the citric acid content of the bones but only in proportion to the reduction of the ash content.In vitamin D deficient rats the citric acid content of the bones is greatly reduced, but in disproportion to the decrease of the ash content. The ratio ash/citric acid in the experiments here reported was about doubled.
The Antinarcotic Effect of Estrone on Alcohol Intoxication
Authors: GOLDBERG LEONARD , STÖRTEBECKER(Oslo) TORE PATRICK 
Published: December 2008

Summary.The effect of estrone treatment on ethyl alcohol intoxation in castrated rabbits has been studied; the degree of intoxication being established by means of reflex criteria and referred to the blood alcohol level.1. Estrone treatment diminishes the degree of alcohol intoxication, STÖRTEBECKER'S (1937 b) observation being confirmed.2. After estrone treatment the animals only attain the same degree of intoxication at a higher blood alcohol level. The difference in blood alcohol concentration has been used as a measure for the antinarcotic effect of estrone.3. The general alcohol metabolism is not affected by estrone, the oxidation rate β and the distribution factor γ being unaltered. The effect of estrone on alcohol intoxication must thus be searched for elsewhere, e. g. in the central nervous system.4. The varying resistance to alcohol depends i. a. on the hormonal state of the individual, and the amount of estrogens in the organism seems to be an important cause.
Über die Oestronwirkung auf den Sauerstoffverbrauch normaler, hypophysenloser und hypophysenstieldurchtrennter Kaninchen.1
Authors: JACOBSOHN D. , WESTMAN A. 
Published: December 2008

Zusammenfassung.Untersuchung des 02,‐Verbrauches narmaler, hypophysenloser und stieldurchtreniiter Kaninchen vor und zu verschiedenen Zeiten nach einer Oestronbehandlung.Der 0,‐Verbrauch stieldurchtrennter Kaninchen ist ebenso stark herabgesetzt wie nach einer Hypophysektomie.Durch die Oestronbehandlung sinkt der 02‐Verbrauch normaler Tiere, während er bei hypophysenlosen und stieldurchtrennten unverändert bleibt.
Studies in Acute but Moderate CO‐Poisoning.
Authors: ASMUSSEN ERLING. , KNUDSEN E. O. E. 
Published: December 2008

Summary.The effect of, acute but moderate CO‐poisoning (25–32 pCt HbCO in the blood) is studied on two normal men. It is found, that the relative cell volume of the blood as well as the plasma protein concentration are augmented after inhalation of CO, suggesting a leaking‐out of fluid from the vessels, presumably due to peripheral vasodilatations. An increased rate of filtration could not be detected in the lower extremity. The amount of glucose and lactic acid in the blood is unaffected by this degree of CO‐intoxication so long as the subject remains quiet. In moderate work the amount of lactic acid increases, whereas the blood sugar still remains normal. The tolerance for glucose is unaffected by this degree of CO‐poisoning. In one of the two subjects the intestine lost its ability to absorb large quantities of water, presumably due to a compensatory vasoconstriction in the intestine. An attempt to demonstrate the effect of a shift of blood from the central (thoracic) vessels to the periphery on the vital capacity of the lungs, failed.