摘要:

AbstractProgressive changes in the S‐T interval of the fetal ECG were studied in 22 lamb fetuses, acutely exteriorized and submitted to graded hypoxia. The ECG changes were studied in order to correlate them with cardiovascular function, as measured by heart rate, mean arterial pressure, end diastolic pressure and combined cardiac output, estimated by the thermodilution method, as well as with blood gases and acid‐base status. Close correlations were obtained between Pao., pH and base deficit and the severity of ECG changes, graded according to a scoring system. Alterations in the ECG pattern consistently preceeded signs of failing cardiovascular function. Our previous findings indicated that the hypoxic ECG changes could be regarded as a sign of myocardial glycolysis. Accordingly, similar progressive ECG changes could be induced by isoprenaline injections. It is concluded that progressive changes of the S‐T interval of the fetal ECG contains information about fetal hypoxic stress before signs of failing cardiovascular function are

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1976.tb10312.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

AbstractIncubation of arachidonic acid and prostaglandin G2with a suspension of human platelets led to formation of an unstable (t1/241 ± 7 s) compound, thromboxane A2Thromboxane A2induced irreversible aggregation of washed platelets and of platelets in platelet‐rich plasma and caused release of serotonin and ADP from platelets in platelet‐rich pl

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1976.tb10313.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

AbstractThis study aimed to quantify changes of vascular compliance and resistance of the proximal and the peripheral pulmonary arterial vessels when vascular smooth muscle was stimulated. These above vascular characteristics were derived from registrations of pulsatile pressure and flow in the pulmonary artery (PA). Anin situcat lung preparation was used, with the right heart by‐passed by a pulsatile blood pump. Vascular input impedance was derived from PA pulsatile pressure and flow recordings, and impedance characteristics were used for calculation of the variables of a simple lumped analog representation of the arterial bed. PA smooth muscle was stimulated by infusions of collagen suspension, by general hypoxia and by nor‐adrenaline injections. Collagen caused 40% reduction of vascular compliance (C), no changes in proximal arterial resistance (Rl) and 18076 increase in peripheral vascular resistance (R2). Hypoxia caused 5096 reduced C, 20% increased R1 and 70% increased R2. Noradrenaline caused 20:6 reduced C and 30 % increased R1 and R2. These results, together with results derived from simulation of the observed impedance changes in a computer model of the lung arterial bed, indicated that collagen infusion elicited contraction of small and medium‐sized arteries, with increased arterial volume as result of increased distending pressure. Hypoxia and noradrenaline, seemed both to cause contraction of the total arterial bed. This effect being most pronounced during hy

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1976.tb10314.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

AbstractEndogenous acetylcholine and biotransformation of tritium‐labelled choline (3H‐CH) were studied in mouse brain regions following different methods of sacrifice, viz. dislocation of the spine (7 min until enzymes inactivated), whole body microwave irradiation (7 s) and irradiation of the head (0.25 s). The brain temperature was measured in different locations 10 to 60 s after irradiation. The slope of the temperature time curves indicated a brain temperature of about 85–90°C at the termination of exposure to both types of irradiation. Acetylcholinesterase (AChE) and choline acetyltransferase (CAT) were practically completely inactivated when measured one to two min after sacrifice.For turnover studies, mice were killed 1, 5, 10 or 20 min after i.v. injection of 15 nmol of3H‐Ch. The brains were dissected into 6 regions, extracted and analysed. No significant difference (except in cortex) in the amount of endogenous ACh was found when whole body irradiation was used in comparison to dislocation of the spine. However, the amount of3H‐acetylcholine CH‐ACh) was much higher in the stri‐atum, hippocampus and cortex, in particular. With the shorter inactivation time (head irradiation) endogenous ACh was markedly increased in the striatum, cortex, medulla, oblongata and midbrain. However, there was no further increase in the radioactive ACh. The difference regarding the post‐mortem sensitivity of endogenous and radioactive ACh does not seem to have been due to methodological artifacts but rather suggests that they are handled differently by the brain tissue. Plots of the specific radioactivity (SA) of Ch and AChus. time indicated fairly distinct precursor‐product relationship in the different regions, when the animals were sacrificed by irrad

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1976.tb10315.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

AbstractThe fatiguability of the quadriceps muscle was investigated in 10 male subjects (25–40 yrs), with inter‐individual differences in fibre composition of their vastus lateralis muscles (range 25–65 % fast twitch, FT, muscle fibres). Fatiguability was assessed as the decline in maximal force (in % of initial values) with 50 repeated isokinetic knee‐extensions at fast angular velocity (3.14 radis). Each contraction lasted 0.5 s and the rest periods were about 0.7 s. Every subject was tested on two occasions and the standard deviation for a single determination of fatiguability was 1.47:., The decline in force after 50 contractions was on the average about 45%. The individual values varied, however, and a linear correlation was present between fatiguability and % FT fibres (r = 0.86, p–.0.01). It was concluded that development of fatigue in human skeletal muscle performing repeated fast dynamic contractions with maximal effort was most marked in muscles with a high proportion FT fibres. This finding was in conformity with earlier results from animal skeletal muscle pre

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1976.tb10316.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

AbstractThe total amount of noradrenaline (NA) in the male accessories increases with normal growth of the organs and also with the age of the rat. The ductus deferens of the old rat has about twice as high NA concentration as that of the young rat. Castration of the prepuberal rat or the puberal rat leads to retardation or cessation, respectively, of the increase in NA amount of the male genital tract. Only in the old rat does castration produce a definite decrease in NA amount of the tract. Castration always raises the NA concentration of the sex accessories. Testosterone treatment of the puberal rat or the old rat produces minor or no increase, respectively, in total amount of NA of the male sex accessories. Testosterone treatment of old prepuberally castrated rats produces a marked increase in NA content of the male organs. It is concluded that androgens have no substancial direct effect on the adrenergic innervation per se, but affects the transmitter levels of the male organs indirectly through changes in number, size and relative proportion of the target cells of the adrenergic nervesi.e. the smooth muscle cells.

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1976.tb10317.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

Abstract58 days old, prepuherally castrated, male rats were treated with estrogen, testosterone or a combination of both hormones for 18 days. The total noradrenaline (NA)‐content of the male accessory glands was increased by the hormone treatments. This increase was smallest in the estrogen treated group and largest in the group treated with both estrogen and testosterone. The NA‐concentration, however, followed the reversed picturei.e. it was largest in untreated castrated rats and smallest in the rats receiving both estrogen and testosterone. Neither treatment brought the NA‐amount up to the level of uncastrated controls of the same age although the weights of the secondary sex glands of rats receiving both estrogen and testosterone exceeded those of uncastrated controls. Similar, but less definite changes were observed in vas deferens and cauda epididymidis. It is concluded that a developing target area exerts some trophic influence on the adrenergic neurons innervating it. However, the trophic influence exerted by the effector organ an the nerves is not of the kind, that the innervation density and NA‐concentration of the organ always are maintained at a constan

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1976.tb10318.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

AbstractThe metabolism of U‐14C‐glucose and U‐14C‐acetate and the interaction between the two substrates in the perfused hind‐quarter of the rat was studied. 5 % of glucose taken up was oxidized to CO., accounting for 15 % of total oxygen consumption. Glucose was mainly incorporated into glycogen, while incorporation into lipids was negligible. Acetate did not significantly alter glucose uptake,14C‐glucose oxidation or the incorporation of14C‐glucose into glycogen and lipids. 45% of acetate taken up was oxidized to CO2accounting for 20–25 % of total oxygen consumption. Insulin did not affect acetate uptake but increased %‐acetate oxidation. Oxygen consumption was slightly increased by simultaneous oxidation of glucose and acetate and in this situation the tissue content of high‐energy phosphate compounds was slightly elevated. It is concluded that only minor effects by acetate on glucose metabolism in the perfused skeletal muscle were found. The insignificant effects compared to previously reported studies on heart tissue (Neely and Morgan 1974) can be explained by differences in acetate metabolism betw

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1976.tb10319.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

AbstractAn emulsion of perfluorotributylamine (Fluosol‐43) was used as substitute for the gas‐carrying function of erythrocytes in a synthetic medium for perfusion of isolated rat liver. The efficiency and effect of this synthetic gas‐carrier were evaluated from measurements of the concentrations of rat albumin, the unsaturated vitamin B.,‐binding capacity of small‐molecular‐size vitamin B12‐binding proteins (UBBC of SBP), urea nitrogen, glucose, sodium, potassium, alanine amino transferase (ALAT) in the medium, and the incorporation of14C‐lysine into the circulating proteins. Secretion of bile, portal pressure, PO2, PCO2and pH in the affluent and the effluent mediums were also measured. The results demonstrate that the oxygen‐carrying capacity of the medium and the metabolic functions of the liver were higher, and the liver damage less, when the medium included Fluosol‐43 than without it. The albumin synthesis and the secretion of bile were as high as has been reported for perfusions with erythrocytes. This indicates that the oxygen carried by the Fluosol‐43 was utilised by the liver, and that the metabolic functions were not adversely affected during 4 h of perfusion by the medium

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1976.tb10320.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

AbstractThe intracellular concentrations of serotonin (5‐HT) in enterochromaffin cells (EC) in the cat small intestine have been studied by a cytofluorimetric method before and after long‐lasting efferent vagal nerve stimulation in the neck. Such stimulation induces a decrease of 5‐HT in EC of the gut as observed previously. Pretreatment with atropine could not block this decrease, suggesting a noncholinergic mechanism. Pre‐treatment with a β‐blocking agent, propranolol, or bilateral removal of the superior cervical ganglia could, however, block this 5‐HT decrease. Pretreatment with an α‐blocking agent, phenoxybenzamine, caused an increase in the 5‐HT content of EC both with and without nerve stimulation; the reason for this is obscure. The results indicate, that vagal nerve stimulation induces a neurogenic 5‐HT release from EC in the gut, and that adrenergic fibres, originating in the superior cervical ganglia, mediate this release probably via a β‐receptor mechanism. Whether or not an α‐receptor mechanism is also involved ca

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1976.tb10321.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY