摘要:

A colloid osmometer for submicrolitre samples was constructed from solid poly‐methylmetacrylate and acrylnitrilmethylmetacrylate blocks, exposing a 0.85 mm diameter area of a Diaflo PM‐30 ultrafiltration membrane. The unknown sample, contained in a 1‐μl glass micropipette, was applied to the membrane by suction, providing minimal exposure to air. The lower limit for successful application was 0.1‐0.2 μl. The accuracy of colloid osmotic pressure(COP)measurement depends strongly on the effective compliance of the pressure transducer. We tested three different systems: (i) A Hewlett‐Packard 1280 ‘medical’ transducer gave acceptable measurements on 1‐μl samples. In smaller samples (0.1‐0.5 μl)COPwas underestimated, especially atCOPgreater than 10 mmHg. The equilibration time was 10–30 min. (ii) As (i), but with air pressure applied to the sample by a servoregulated pump, minimizing fluid transport through the membrane. Accurate measurements on 0.2‐,μl samples were obtained in the course of 2–3 min, but the system required special instrumentation and some operating experience, (iii) An ‘industrial’ transducer, SensoNor AE‐880, with very low compliance, gave accurate measurements in the course of 1–3 min on samples as small as 0.1‐0.2 μl andCOPup to 37 mmHg. We recommend sy

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1988.tb08351.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

The immunohistochemical expression of the trophic peptide insulin‐like growth factor I (IGF‐I; somatomedin C) was investigated in the post‐ischaemic regenerating rat kidney. The part of the nephron most severely injured by the ischaemic insult was the pars rectae or S3region of the proximal tubules. In this part of the nephron no specific IGF‐I immunoreactivity could be demonstrated under control conditions. Three days after injury, however, low regenerating tubular cells expressing IGF‐I immunoreactivity could be demonstrated invading the damaged region. Five and 7 days post‐ischaemia some of the regenerating cells showed IGF‐I immunoreactivity while adjacent and similar‐looking cells did not. In parallel with an increasing differentiation of the regenerating cells the IGF‐I immunoreactivity vanished. Fourteen days after the injury the S3cells had regained their normal morphology, and by this time the IGF‐I immunoreactivity had returned to a normal undetectable level. It is concluded that there is a transient increase in the expression of IGF‐I mainly confined to the early phase of post‐ischaemic rat kidney regeneration. It is proposed that IGF‐I exerts its trophic rol

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1988.tb08352.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

The putative influence of the thermoregulatory state on skin blood‐flow responses to various stimuli was studied in 17 healthy subjects exposed to different ambient temperatures. Skin blood flow was monitored by laser Doppler flowmeters and photoelectrical pulse plethysmographs. Stimuli included painful intraneural electrical stimulation (INS) in the median nerve at the wrist, mental stress, arousal stimuli and deep breaths. Intraneural electrical stimulation and mental stress were accompanied by virtually identical changes in skin blood flow, warm subjects responding with cutaneous vasoconstriction whereas cold subjects responded with vasodilatation. Similar but less pronounced responses were obtained with arousal stimuli and single deep breaths. The data indicate that the thermoregulatory state profoundly influences the extent and direction of various cutaneous vasomotor reflex responses. Furthermore, there were differences between responses in hands and feet, suggesting a spatial organization of vasomotor contro

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1988.tb08353.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

In chloralose anaesthetized cats with renal arterial pressure kept constant at 100 mmHg, vascular expansion with precirculated blood, 20 ml kg b.w.‐1, caused significant increments in arterial inflow rates of blood to the deep (ARBFD) and superficial (ARBFS) renal venous drainage area of 35 ± (SE)10 and 19 ± 6%, respectively, and in the excretion rates of water and sodium of 73 ± 24 and 75 ± 28 %, respectively, while GFR remained essentially unchanged. In acutely denervated kidneys the responses to expansion were not significantly different from those of innervated kidneys, which indicated largely humoral mediation. Arterial plasma concentrations of noradrenaline, adrenalin, and vasopressin fell significantly to values of a half to one‐third of pre‐expansion values, while plasma dopamine was not significantly changed by expansion. The response to expansion could be (1) reversed by a ‘substituting’ intraaortic infusion of noradrenaline, and (2) imitated, without volume expansion, by an infusion of an a‐adrenergic blocking agent (phentolamine). It is concluded that the renal response (excretory and vascular) to volume expansion with blood is largely humorally mediated and that circulating noradrenaline may play a causal role

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1988.tb08354.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

The ability of adenosine to inhibit sympathetic nerve‐stimulation‐induced overflow of noradrenaline was studied in isolated rabbit hearts with intact sympathetic innervation. Noradrenaline in the heart effluents was measured by HPLC with electrochemical detection. The drugs used, adenosine, theophylline, and 8‐parasulphophenyltheo‐phylline, were administered via the perfusion fluid. Adenosine (1–100 μM) dose‐dependently inhibited stimulation‐evoked outflow of noradrenaline from the heart, by up to 47%: the inhibition was completely antagonized by theophylline (200μM), AND by 8‐parasulphophenyltheophylline (100 μM). Neither theophylline nor 8‐parasulpho‐phenyltheophylline didper seaffect basal or stimulation‐evoked outflow of noradrenaline. Simultaneous infusion of adenosine (100μM) AND theophylline (200 μM) significantly increased the outflow of noradrenaline during nerve stimulation, by almost 40%. No such effect was observed by adenosine (100 μM) AND 8‐parasulphophenyltheophylline (100 μM), indicating that theophylline may facilitate transmitter release by an action dissociated from purinoceptor antagonism. It is concluded that (a) adenosine inhibits depolarization‐induced liberation of sympathetic transmitter in the rabbit heart, (b) this inhibition is mediated by activation or purinoceptors, probably located on the presynaptic nerve terminals, and (c) brief periods of sympathetic stimulation in the normoxic heart does not release sufficient amounts of adenosine to cause significant i

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1988.tb08355.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

The effects of noradrenaline (NA)‐induced vasoconstriction on the transcapillary passage of albumin was evaluated by an external detection technique, allowing repetitive measurements of albumin clearance (Cl) during various conditions (in the same animal). Six isolated rat hindquarters were perfused with serum‐albumin solutions during maximal vasodilation (papaverine 90 μM) ANDClwas determined at different net filtration rates(Jv)induced by elevations of venous pressure. Then, the perfusate was changed to one of similar composition but containing noradrenaline (2–4 μM), AND the procedure of determiningCl vs. Jvwas repeated. Tissue accumulation of [99mTc]albumin was expressed in terms of clearance, using the isogravimetricCIof defined muscle samples during maximum vasodilation in separate experiments as reference, the latter being 0.0246 ± 0.0012 ml min‐1per 100 g. Noradrenaline caused an increase in vascular resistance from 2 to 14 mmHg min 100 g ml‐1, while theCl vs. Jvrelationship was shifted downwards in a fashion parallel with the controlCl vs. Jvcurve. ForJv =o,Clwas 0.0101 ± 0.0014mlmin‐1per 100 g during NA challenge. The average reflection coefficient for albumin (σtot) was 0.92 ± 0.01 irrespective of vascular tone. Thus, both albumin clearance and the capillary filtration coefficient(CFC)seem to vary in direct proportion to the capillary surface area avail

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1988.tb08356.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

The significance of ischaemia of the left ventricular (LV) and right ventricular (RV) free walls for the dynamics of the interventricular septum (IVS) and the right ventricle was examined in open‐chest dogs. Left ventricular and RV ischaemia reduced stroke volume similarly, by 11.2 ± 1.4% and 11 2 ± 2.4%, respectively. The dynamics of myocardial segment lengths (SL), recorded in the LV and RV free walls and the IVS, differed. During LV ischaemia, end‐diastolic SL (EDSL) and systolic shortening (SS) increased in the IVS, whereas SL remained unchanged in the RV free wall. During RV ischaemia, LV EDSL, and SS decreased. Interventricular septum EDSL also decreased, but this reduction was not statistically significant. During blood volume expansion, LV and RV function curves were shifted right, and/or downwards by LV ischaemia, whereas only the RV function curve was shifted downwards and to the right by RV ischaemia. Thus, ischaemia of the LV free wall induces activation of the Frank‐Starling mechanism in the interventricular septum and a deterioration of right ventricular perf

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1988.tb08357.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

Biopsies from m. quadriceps femoris from the operated leg of nine patients were taken before, and 6 weeks after, knee surgery. During the whole postoperative period the operated leg was immobilized with the knee in 40–500of flexion. Myoglobin (MYO) and the enzymes citrate synthase (CS), creatine kinase (CK) and its isozymes MB (CK‐MB) and mitochondrial CK (CK‐MIT), aspartate aminotransferase (ASAT), phospho‐fructokinase (PFK) and lactate dehydrogenase (LD) were determined on the biopsies. Citrate synthase, ASAT, CK, CK‐MB, CK‐MIT and LD activities were decreased (12–30%) after the postoperative leg immobilization period. Phosphofructokinase did not change, while MYO content was increased (16%). In conclusion, a different control of the synthesis of oxidative enzymes and MYO is suggested, as the induced changes following immobilization were in opposite directions. The function of the increased MYO content may be to facilitate the oxyg

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1988.tb08358.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

The release of brain‐gut peptides during sauna bathing was studied in seven women. All'women underwent a 20 min sauna bath. Their sublingual temperature rose from 36.9 ± 0.1oC to 38.6 ± 0.2oC (mean ± SEM). A significant increase in circulating plasma vasoactive intestinal polypeptide (VIP) was observed during heat exposure, whereas plasma pancreatic polypeptide (PP), motilin and blood glucose rose and stayed significantly elevated first during the ensuing 60 min(P<0.05 in all cases). A similar increase in plasma insulin failed to reach statistical significance, whereas the plasma levels of somatostatin and cholecystokinin (CCK) remained unchanged. It is suggested that the plasma VIP levels are related to compensatory mechanisms during heat exposure with vasodilatation and heat

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1988.tb08359.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

The isokinetic (30, 60, 120 and 1800s‐1) peak torque of m. quadriceps femoris and m. triceps surae, and the running velocity at the onset of blood lactate accumulation (V0BLa)were determined at three different occasions (November, April and September) during a year in 15 male elite orienteers. The amount and type of training for each individual was also registered.At the first test (November) there was no significant intra‐individual correlation between peak torque of m. quadriceps and m. triceps surae. A negative correlation was found betweenV0BLAand peak torque of m. quadriceps at the lower velocities of angular motion, but not at the higher. The peak torque of m. triceps surae increased during the training period and decreased during the competition period back to the original level. Over the whole year the peak torque of m. quadriceps increased while no changes could be demonstrated within the two periods of the study. The running velocity at the onset of blood lactate accumulation increased during both training and competition periods. The changes inV0BLawere negatively associated with the changes in peak torque of m. quadriceps at 1800s‐1during the training period. During the competition period the changes inVOBLAwere, for the majority of the orienteers, negatively correlated to the ratio of quality: quantity running, i.e. to a high content of forest ru

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1988.tb08360.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY