摘要:

Summary.Nerve impulses in the medial articular nerve to the knee joint of the cat have been studied. The responses of sensory nerve endings located in the knee to position and movement of the tibia are described. The endings are slowly adapting and seem to be arranged sothat each has an arc of maximum sensitivity covering a few degrees of angular movement but these ranges are different for individual endings. The significance of this is discussed.The medial femoro‐tibial and the patellar ligaments were found to be equipped with endings which signalled tension. The responses of these endings to steady tensions were measured.An increased intracapsular pressure was produced by injecting fluid into the synovial cavity. Simultaneous recordings of pressure and impulse traffic show that a raised pressure was a potent stimulus to slowly adapting endings in the capsule.The articular surfaces and the synovial membrane were found insensitive to moderate mechanical and thermal stimulatio

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1953.tb00982.x

出版商:Blackwell Publishing Ltd    

年代:1953

数据来源: WILEY

摘要:

Summary.Chromaffine cell tissue from Selachiae and Teleostiae contain noradrenaline and adrenaline in varying proportions.Visceral'organs of fish (heart, liver, spleen) contain noradredille in about 1/10–1/50 of the amounts found in the corresponding organs of mammals, as estimated by biological assay. The proportion of adrenaline was much higher than in mammals, viz. 40–60 % of the total catechols.No definite evidence was obtained for the presence of catechol amines in invertebrates (mollusc, crustacean, echinoderm) with the exception of the posterior salivary glands ofOctopus vulgariswhich contain comparatively large amounts of noradrenaline.The catechol amines in extracts of visceral organs of fish indicate the presence of chromaffine cells or adrenergic innervation.The author is indebted to the Head and Staff of the Roscoff Marine Biological Station for supplying some of the material. The Medical Research Council of Sweden defrayed the cost of this work with a grant which is gratefully acknowled

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1953.tb00983.x

出版商:Blackwell Publishing Ltd    

年代:1953

数据来源: WILEY

摘要:

Summary.The investigation is carried out on the flyCalliphora erythrocephalaand concerns how the metabolic energy is utilized during the metamorphosis and which metabolic pathways are followed.The amount of protein, carbohydrate and fat were determined during the pupal life by the aid of biochemical analysis and by histochemical detection. The corresponding enzyme systems and the phosphorus metabolism were also studied.No nitrogen excretion occurs during the pupal life. The decomposition of proteins occurs only to a limited extent and goes probably only as far as to peptides. These peptides seem to be combined with phospholipids.The main fuel during the pupal development is fat supplemented by a small amount of carbohydrate. Very probably there is an interconversion of fat and carbohydrate. Anaerobically only carbohydrate is utilized. Principally the same glycolytic processes work aerobically as anaerobically. The anaerobic utilization of energy is very low compared with the aerobic. Anaerobiosis represents anabiosis.The U‐shaped metabolic curve can be explained by a corresponding decomposition of oxidative enzymes. Three physiologically‐conditioned periods during the pupal life can be distinguished: histolysis, histogenesis and differentiation. During the differentiation an incorporation occurs of soluble protein into the cell structure, a fixation of enzymes in the mitochondria. The adenosine triphosphatase activity is restored first during the differentiation period.Different pathways are utilized for energy gain. Thus, the glycolytic and the cyclophorase systems show an alternating variation during the metamorphosis indicating that growth and glycolysis are connected as well as differentiation and cyclophorase system. The glycolytic and the cyclophorase systems do not seem to be strictly cocatenated.The influence of anaerobiosis on respiratory enzymes was studied. During anaerobiosis an inactivation of the protein part of the enzymes occurs. By investigation of the restitution period histolysis was found to be an active process. The lethal influence of anaerobiosis on the developmental stage of the pupa is correlated to the respiratory activity with the exception of 70 per cent of the pupal age, where a temporarily increased lethal influence was found. This marks this state as a critical period in the development.The phosphorus metabolism was closely studied. The variation in amount of different phosphorus‐fractions during the development was established. The total phosphorus is constant during the metamorphosis period. Protein‐phosphorus, a part of the lipid‐phosphorus and the more easily hydrolyzable phosphorus have a U‐shaped variation. Low molecular phosphorus compounds are liberated during histolysis and later on incorporated. Des‐oxyribonucleic and ribonucleic acid vary inversely. An increase is desoxyribonucleic acid‐content is found in the histolysis center which do not correspond to an increase in Feulgen positive substance. The utilization of adenosine triphosphate decreases during histolysis, increases during histogenesine and decreases again during differentiation in accordance with the occurrence of synt

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1953.tb00984.x

出版商:Blackwell Publishing Ltd    

年代:1953

数据来源: WILEY

摘要:

Summary.1. The permeability of isolated frog skin to heavy water was measured. At the same time the electrical d. c. conductance was recorded as a measure of the permeability to ions.2. The mean permeability coefficient of normal skins for heavy water is 73 × 10–6cm sec.‐l, which is estimated to be about 50 times greater than a corresponding permeability coefficient for Cl (and Na) ions.3. The permeability to heavy water is not appreciably influenced by the action of mersalyl (0.1 mM) and aminophylline (50 mg per cent). But aminophylline causes a considerable increase in the conductance or permeability to ions. Thus there is no noticeable covariation between the permeability of frog skin to water and to ions.The investigation was supported by a grant from the Therèse and Johan Andersson

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1953.tb00985.x

出版商:Blackwell Publishing Ltd    

年代:1953

数据来源: WILEY

摘要:

Summary.Neither the drinking of 666 ml beer, water or 2.7 per cent alcohol nor the continuous injections of 17.5 mg per min. of theophyl‐line‐1‐aminopropanol (“oxyphylline”) had any measurable influence on the renal plasma flow in man as examined with the PAH clearance.During beer‐ and “oxyphylline” diuresis the inulin clearance was significantly increased in comparison to the clearance during water diuresis or after drinking of the corresponding amount of 2.7 per cent alcohol.Beer and “oxyphylline” were without measurable effect on the “endogenous

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1953.tb00986.x

出版商:Blackwell Publishing Ltd    

年代:1953

数据来源: WILEY

摘要:

Summary.The effect of the drinking of moderate amounts of beer on the renal excretion of water, sodium and potassium was studied on a number of healthy human subjects. Beer was found to increase the output of water and sodium and to decrease the potassium excretion. This effect seems b arise in the beer during its fermentation. Beer without hops was effective but not unfermen‐tated malt extract. The alcohol in the beer did not seem to be responsible for the effect, because a mixture of brandy and water or brandy and malt extract with the same alcohol concentration as the beer was without effec

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1953.tb00987.x

出版商:Blackwell Publishing Ltd    

年代:1953

数据来源: WILEY

摘要:

Summary.It was the purpose of the present experiments to determine the ratiocost of positive work: cost of megative workunder different conditions of work.The cost of the work was expressed as the oxygen uptake per minute in the steady state of work. The work itself consisted in riding a bicycle on the inclined belt of a motordriven treadmill, uphill for positive work, downhill for negative work. The rate of work was expressed in kg/m per minute and defined as the product of the weight of subject plus bicycle and the vertical distance of lifting or lowering this weight per minute.The oxygen uptake per minute (y) plotted against the rate of work (x) was found to lie on two straight lines for the two kinds of work, and the equations for these two lines could be expressed as y = bposx + aposfor positive work and y = hneg+ anegfor negative work.Under the same conditions of speed, saddle height and pedal length aposand anegwere found to be identical and are assumed to represent the cost of extra work (balancing, postural efforts etc.) plus the resting metabolism. bpos: bnegshould consequently represent the ratiocost of positive work: cost of negative work.The ratio bpos: bnegwas found to increase from 3.1 ± 0.7 to 6.1 ±w 0.7 when the distance saddle to crank increased from 60 to 90 cm, and the pedal length and velocity of movement were constant.Variation of the pedal length between 8.5 cm and 25.5 cm with constant velocity of muscular movements and saddle height had no statistically significant effect on the ratio, which under these conditions was found to lie between 7.0 and 9.3.With increasing speed of movements the ratio increased from 5.9 to 125, mainly because bnegdecreased and approached zero.The results are discussed under consideration of the length‐tension diagrams and the force‐velocity curve of isolated muscle.It is concluded that besides the effects that could be expected from the form of the length‐tension diagrams and from the force‐velocity curve another factor must be responsible for the very low values of bnegand the high value of bpos: brneg. It is tentatively suggested that this factor is the reversal of the chemical processes in excentric muscle contractions previously found by Abbott, Aubert and Hill (1951).The author wishes to express his sincere thanks to Mr. P. Rosenfalck, M. Sc., and to Dr. Steen Knudsen, both of the Neurophysiological Institute, Copenhagen, for their kind help with the statistics in this work and for many suggestive discussions during its progress. Dr. Steen Knudsen designed the filter used as an integrator of the electromyograms

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1953.tb00988.x

出版商:Blackwell Publishing Ltd    

年代:1953

数据来源: WILEY