摘要:

AbstractAn indicator‐dilution technique is described for studying intestinal mucosal red cell and plasma flow and volume quantitatively and muscularis red cell and plasma flow and volume qualitatively. The technique involves a close intra‐arterial injection of an intravascular β‐radiating tracer and its detection with sensoring devices placed in the gut lumen and outside the intestine at the antimesenteric border. Knowing the amount of tracer injected and total venous outflow, it is possible to estimate regional flow from the height of the registered curve and regional blood volume from its area. Since the volume of the region monitored by the detector depends on the energy level of the β‐radiation,32P‐labelled red cells and plasma colloids, used in this study, were monitored from the whole mucosa, while108Au‐labelled plasma particles were registered only from the villi. This paper presents the theoretical background of the technique and some mode

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1973.tb05410.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

AbstractProlonged hemorrhagic hypotension and multiple trauma not involving the lungs can, in patients, induce respiratory failure with a fall in lung compliance and a concomitant increase in the work of breathing (Mooreet al.1969). However, animals experiments have revealed conflicting results concerning the magnitude and direction of change in lung compliance after a hemorrhage. We have studied the effects of 3 hr of hypovolemic systemic hypotension (femoral a. pressure: 50 to 60 mm Hg) on lung mechanics in open chest cats ventilated by positive pressure.Mean dynamic lung compliance (CL) rose during the first 30 min post‐bleeding by 13 ± 5 per cent whereafter CLgradually fell to 26 ± 6 per cent below its initial value, in the third hr of observation. On the basis of our monitoring of vascular parameters and alveolar‐arterial PO2differences we suggest that the early rise in CLis due to reduced pulmonary blood volume and vascular distending pressure, whereas the later fall in CLis caused by collapse and narrowing of peripheral airways. No signifiant changes in nonelastic (frictional) resistance could be detected during the 3 h observation p

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1973.tb05411.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

AbstractThe effects of the oxybarbiturate Amytal and the thiobarbiturate Inactin on isosmotic fluid absorption by the rabbit gall‐bladder in vitro sac‐preparation was studied. Both barbiturates inhibited net fluid transfer rate. The effect was dose‐dependent. Inactin was a more potent inhibitor than Amytal with effect from the serosal side at concentrations down to 1 × 10‐4M (i.e.below concentrations obtained in plasma of anesthetized rats); inhibition by Amytal unilaterally was not observed at concentrations below 1 × 10‐3M (a concentration above that of plasma of anesthetized rats). Amytal depressed oxygen consumption in parallel with net fluid transport rate, while Inactin was without any significant effect on oxygen consumption in spite of severe inhibition of net fluid transport rate. The inhibitory effect of Amytal applied bilaterally was reversible after exposure to the drug for more than 60 min. The effect of brief exposure (20 min) to Inactin bilaterally was reversible; after exposure for 60 min or more the effect was irreversible in recovery periods of up to 60 min duration. Both barbiturates accumulated in the gall‐bladder tissue with a concentration factor of about 1.5. After washing in barbiturate‐free Ringer solution (recovery periods) for 45–60 min, neither Amytal nor Inactin were detectable in the tissue. The sensitivity of the method allowed detection of 0.2 mM Inactin per kg wet weight,i.e.no more than 2% of the Inactin accumulated during the experimental period. The data suggested that the effects of the two barbitura

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1973.tb05412.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

AbstractDuring enhanced glycogen synthesis an increase in the activity of the enzyme rate‐limiting for glycogen synthesis is expected. This enzyme, glycogen synthetase (UDP‐glucose: α‐1,4‐glucan, α‐4‐glucosyltransferase; EC 2.4.1.11), can be activated by transformation of its D‐form to I‐form. Insulin is known to stimulate glycogen synthesis in skeletal muscle. However, Søvik did not find any change in I‐form in the rat diaphragm 30–240 min after an intraperitoneal (i.p.) injection of insulin, although glycogen synthesis was highly stimulated (O. Søvik, Acta physiol. scand. 1966.68.246–254). In the present study glycogen content and synthetase enzyme activity were measured in rat diaphragms 10–120 min after i.p. injection of insulin. Phosphorylase enzyme activity was also measured. Insulin administration produced a biphasic change in the synthetase enzyme; compared to controls there was an increase of the % I‐form after 10 and 20 min and a decrease after 50, 80 and 120 min. Phosphorylase enzyme activity was unaffected. Glycogen increased continuously up to 120 min. Thus, the increase in I‐form was shown to be a transient effect of insulin. In Søvik's experiment this increase had probably subsided at the time of the first measurement. To account for the increase in glycogen when the % I‐form was decreased, an activation of the synthetase enzyme through an increase of its activator, gluc

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1973.tb05413.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

AbstractThe specific sodium and potassium permeability mechanisms in the nodal membrane were analysed. The current to potential relations were measured with various external concentrations of NaC1, KC1 and CaC12. PNaand PKwere calculated. The measurements showed that the permeability to potential curve was shifted along the potential axis and in the same direction for changes in the uni‐univalent salt concentration as well as for changes in [Ca]. The shift caused by changes in [Ca]was larger at low uni‐univalent salt concentrations and the shift caused by [K] and [Na]increased with decreased [Ca]. It was assumed that the membrane has negative charges fixed to its outside surface. The permeability shifts were approximately predicted by a charge density of‐5.5 μC μ cm‐2. A decrease in [Na], but not in [Ca]caused a decrease in PK. This behaviour was not

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1973.tb05414.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

AbstractThe effect of training on the skeletal muscle metabolism of 11‐to 13‐year‐old boys was examined. In one experiment changes in blood lactate, and muscle lactate, CP, ATP, and glycogen were determined at rest and following exercise before and after 4 months of training. The concentrations of glycogen, CP and ATP at rest were higher (P<0.01) following training. Blood and muscle lactate were 23 and 56 % higher after maximal work following training. A greater reduction in muscle glycogen occurred during maximal work after training but the pattern for ATP and CP depletion was unchanged. In a second experiment boys trained by pedalling a bicycle ergometer an average of 30 min 3 times a week for 6 weeks. Biopsy samples of the vastus lateralis were examined for oxidative (succinate dehydrogenase) and anaerobic (phosphofructokinase) capacity before and after training. The fiber composition and relative oxidative capacity in the fibers was determined histochemically. Succinate dehydrogenase and phosphofructokinase activities increased 30 and 83 %, respectively, following training. Fiber distribution was unchanged by training but the oxidative capacity of both fiber types appeared to inc

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1973.tb05415.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

AbstractUsing precision calorimetric techniques for measuring extremity heat loss, possible contraindications or advantages of alcoholic or hot drinks or smoking just prior to cold exposure were assessed. Ten subjects were given 60‐min exposures with one hand and one foot immersed in 15° C water, following the drinking of 1. 200 ml of 23° C water (control), 2. 200 ml of 23° C water containing 22 ml of absolute alcohol, 3. 200 ml of 55° C bouillon, 4. 200 ml of 23° C water and smoking 2 cigarettes. No significant effects were noted in the foot, but significant differences were observed in hand heat loss to the calorimeter; smoking depressed hand heat loss, alcohol elevated it. Smoking had a persistent influence, but the effect of alcohol had disappeared after 30 min. Bouillon had an effect similar to alcohol, but of shorter duration, and also resulted in a significantly reduced heat loss after 30 min. Alcohol produced a significantly higher amount of cold induced vasodilatation (CIVD) with greater total temperature elevation in 3 fingers than did smoking, although smoking did not prevent CIVD. With intake of bouillon, CIVD appeared earlier than with alcohol, and during the 1st 15 min, total temperature elevation in the 3 fingers was markedly higher than in the control run, but not as large as with alcohol. All differences were relatively small and would seem to be of little practical impo

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1973.tb05416.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

AbstractVentilation, heart rate and arterial pressure were recorded in rats on blood losses from 1 to 6 ml (6–36 % of blood volume). About 15 s after the onset of the blood drawing and the coincident decrease of arterial pressure, the tidal volume increased on a loss of 1–3 ml. This was regularly observed in 10 rats. On larger hemorrhages the tidal volume decreased. The respiratory rate decreased in some animals already at a blood loss of 1 ml, in others at losses above 2 ml. The increase of the tidal volume was totally inhibited in 5 rats by exclusion of afferents in the recurrent nerves by cold block or section. In three other rats the increase of the tidal volume was inhibited on cutting also of the right or both vagal nerves. The decrease of tidal volume and of respiratory frequency on large blood losses was not inhibited by vagotomy. It is presumed that the increase of the tidal volume on a small to moderate blood loss is provoked by a vagal reflex elicited by receptors on the low pressure side and that the decreased ventilation on larger hemorrhages is elicited from the respiratory centres by the change of the cerebral blood f

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1973.tb05417.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

AbstractThe distribution of renal cortical blood flow was studied in seven Nembutal anesthetized dogs in control periods, during hemorrhagic hypotension and after retransfusion. Local cortical blood flow was measured as hydrogen clearance recorded simultaneously from 3 to 6 platinum electrodes inserted into inner and outer half of the cortex. Total renal blood flow (RBF) was measured by electromagnetic flowmeter. In control periods flow averaged 3.47 ± 0.83 ml/min×g in outer cortex and 3.61 ± 0.86 ml/min × g in inner cortex. Bleeding to mean arterial pressure of 50 mm Hg in the course of 5–36 min in 5 expts. caused a proportional reduction of RBF and average flow in outer and inner cortex to 40–60 % of control, with further reduction to 10–30 % with maintenance of hypotension for 2 h. Bleeding to 70 mm Hg in 2 expts. gave princpially the same response. All electrodes showed a similar response and the percentual deviation between electrodes did not increase during hypotension. Thus no evidence was obtained for patchy or segmental ischemia or for regional redistribution of cortical blood flow. Retransfusion gave only incomplete restoratio

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1973.tb05418.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

AbstractThein vivoandin vitroeffects or 5‐hydroxytryptamine (5‐HT) were investigated on the mesenteric vasculature of the cat. Close i.a. injections (10 μg) or infusions (10–15 μg/min) into the superior mesenteric artery of chloralose anesthetized cats generally induced an intestinal vasodilatation of 60–150 % above control which was unaltered by α‐or β‐adrenergic or cholinergic receptor blockade, and which after its development was unaffected by intestinal motility responses. Following nerve blockade by tetrodotoxin, the vasodilator response to 5‐HT was changed to vasoconstriction. During 5‐HT infusions of 20–50 μg/min intestinal blood flow and intestinal capillary filtration coefficient (CFG), measured plethysmographical‐ly, increased significantly above control, while at infusions of 10–15 μg/min 5‐HT increased CFC without increasing intestinal blood flow. Inin vitrostudies on strips or segments of mesenteric arteries and veins from the cat and rat, 5‐HT constantly increased isometric tension in all vessels studied. The response was unaltered by adrenergic or cholinergic receptor blockade and was not related to passive tension applied to the vessels nor to the presence or absence of noradrenaline in the bath. The divergentin vivoandin vitroresponse are discussed in terms of the following possible mechanisms: 1. A differential effect of 5‐HT with constriction of large vessels and dilatations of smaller ones; 2. A direct constrictor effect on the vascular smooth muscle via specific serotonic receptors, as well as an indirect dilator effect, perhaps mediat

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1973.tb05419.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY