摘要:

AbstractArterial pulsations have been recorded indirectly from the surface of the rat's tail. Slight heating of restrained unanesthetized rats produces vasodilatation and large amplitude pulsations that are influenced by sensory stimuli, in this case, sound. The surface‐recorded pulse volume was found to be proportional to pulse pressure, indicating vasoconstriction as the cause of the decline of the pulse amplitude. A one‐second noise burst elicited vasoconstriction, the duration of which was proportional to sound level and occurred as low as at hearing threshold. Under the specified conditions, reproducibility was good with no significant habituation both within session, and between sessions with a one week interval. The warming of the rats was found to be critical for the sound‐elicited reactions; responses were obtained only within a narrow, individual temperature‐range. The possibilities of using tail vasoconstriction for evaluation of hearing was pointed out, as well as for studies of noise effects on peripheral circ

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1977.tb05930.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

AbstractMaximum effort flow‐static recoil curves were obtained in 5 healthy subjects breathing air, He/O2, and SF6/O2mixtures. In 4 of them maximum effort flows corresponded to really maximal flows and their curves were transformed into compliance curves for the flow limiting segments of the airway and analyzed from the point of view of a previously presented lung model (Pedersen and Nielsen 1976). The results showed, that viscosity dependent pressure losses from the alveoli to the flow limiting segments were minimal for air and SF6/O2, but not for He/O2. When viscosity dependent pressure losses could be neglected, then expiration of gases of different densities gave almost identical compliance curves for the flow limiting segments. This supported the applicability of the model. The calculated compliance curves for the flow limiting segments were compared with data from the literature, and the findings indicated that flow limitation during expirations with just maximal flows throughout began in the extrapulmonary airways and moved upstream during the expiratio

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1977.tb05931.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

AbstractBlood flow in the circumflex branch of the left coronary artery was recorded by electromagnetic flowmeter. In the area supplied by this branch vasodilatation was produced by progressive constriction until the diastolic reactive hyperemic response to 10 s occlusion disappeared (“optimum” stenosis). This degree of stenosis was accompanied by a 20% decrease in diastolic circumflex flow, while systolic flow remained unchanged. The distribution of blood flow in the left ventricular free wall was evaluated at “optimum” stenosis by counting activity in tissue blocks following bolus injection of Xe‐133 into the aortic root. When Xe‐133 was injected immediately after occlusion of the left anterior descending branch the Xe‐133 concentration of the endocardial part of the area supplied by the circumflex branch was about half the concentration in the epicardial part. The concentrations in the two parts did not, however, differ significantly when occlusion of the left anterior descending branch was omitted. This indicates that the endocardial blood flow reserve is lower than the epicardial, and that, yet, a preferential fall in blood flow in the endocardial part of a post‐stenotic area can be rapidly eliminated when blood supply from a neighbouring arte

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1977.tb05932.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

AbstractThe effects of prostaglandins F2α(PGF2α), E2(PGE1) and E2(PGE2) on the human lower urinary tract were studiedin vitroin preparations obtained from patients undergoing total cystourethrectomy because of bladder malignancy. Tissue specimens were taken from different parts of the urethra, the urethrovesical junction, and the bladder. From these specimens, smooth muscle preparations were dissected and mounted in organ baths, that were filled with Krebs solution (37°C) and bubbled with carbogen. Isometric tension was recorded. Preparations from the bladder and all parts of the urethra were contracted by PGF2α. This effect was not affected by tetrodotoxin, phenoxybenzamine, or atropine; isoprenaline relaxed the PGF2αinduced contractions. PGE1and PGE2both contracted strips from the bladder. However, urethral preparations contracted by PGF2αor noradrenaline were relaxed by these agents. This relaxing effect was at least as pronounced as that produced by isoprenaline; it was not affected by propra

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1977.tb05933.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

AbstractThe effects of some analogues of PGE1, PGE2and PGF2α, rendered less accessible to the action of prostaglandin dehydrogenase by having methyl groups at carbons 15 and/or 16, or a phenyl group at carbon 17, on the tracheobronchial insufflation pressure in guinea pigs and on the tone of isolated human bronchi were investigated. Regardless of route of administration, i.v. injection or aerosol administration, PGE1,16,16‐dimethyl‐PGE1, PGE2, the methyl esters of 15(R)15‐methyl‐PGE2and 15(S)15‐methyl‐PGE2, 16,16‐dimethyl‐PGE2and its methyl ester, and 17‐phenyl PGE2all produced a dose‐dependent inhibition of the histamine‐induced increase in insufflation pressure and a fall in systemic blood pressure in the anesthetized guinea pig. Although the duration of action of the PGE‐analogues was longer than that of the parent compounds, none of them was more potent with regard to the peak effect produced on insufflation pressure. Of the PGF2αanalogues studied, 16,16‐dimethyl‐PGF2αwas the most potent compound, in decreasing rank order followed by 15(S)15‐methyl‐PGF2α, 17‐phenyl‐PGF2αand PGF2α, in eliciting an increase in insufflation pressure on i.v. injection. On aerosol administration, only 16,16‐dimethyl‐PGF2αcompound was more potent than PGF2αOn isolated human bronchi, PGE1and PGE2were consistently relaxant, although in some expts. the relation to PGE2was followed by constriction. The 16,16‐dimethyl analogues of PGE1and PGE2were consistently bronchoconstrictor whereas the effects of the other PGE–analogues were weak and inconsistent. In comparison with the bronchorelaxant β2‐adrenoceptor stimulating compounds, the PGEs and PGE‐analogues studied do not have any outstanding

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1977.tb05934.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

AbstractIn order to study if rapid elevation of blood pressure is associated with cerebral ischemia, anesthetized (70% N2O) and artificially ventilated rats were subjected to angiolensin‐induced hypertension. After a 5 min hypertensive period, cerebral cortex tissue was frozenin situfor subsequent measurements of labile glycolytic metabolites, ammonia, and organic phosphates. The degree of hypertension induced, which gave evidence of blood–brain barrier damage in 7 of 8 rats, did not affect the tissue concentrations of labile metabolites. It is concluded that ischemia does not contribute to the barrier damage, nor is it likely to be the cause of the clinical symptoms that may occur in conscious rats in the same experimental mo

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1977.tb05935.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

AbstractIn standing human subjects, muscle spindle activity was recorded from peroneal nerve fascicles innervating anterior compartment muscles. Provided that the receptor‐bearing muscle remained relaxed, the basal activity and responses to stretch seen in multi‐unit and single unit afferent recordings were stable and not altered by eye‐closure or assistance to balance. The discharge frequencies of single afferent fibres were similar to those recorded at comparable muscle lengths in relaxed reclining subjects. By analogy to findings in reclining subjects, these results suggest that, during standing, the background fusimotor drive to relaxed muscles is negligible. Backward body sway can induce a sway‐stabilizing reflex contraction in the muscles of the anterior compartment. Such reflex contractions were accompanied by increased muscle spindle activity, the intensity of which appeared to be related to the intensity of the skeletomotor contraction. When balance was assisted by holding a support, swaying movements of similar or greater amplitude and velocity did not produce reflex activity, and the spindle response was of low frequency. It is concluded that the sway‐stabilizing reflex contraction operates in alpha‐gamma linkage, and that these contractions are not generated by segmental stretch refl

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1977.tb05936.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

AbstractThe present work was aimed at studying the first stages of disappearance of particulate cholesterol from the circulation. The distribution of radioactivity in blood, liver, spleen, lungs and kidneys was determined at different time intervals after i.v. injections of aqueous‐ethanolic dispersions of radioactive cholesterol to rats. More than 95% of the dose disappeared from the circulation in 10 min. From 71 to 93% of the dose was found in the liver 5 min‐2 h after the injection. According to autoradiography, most of the particulate cholesterol was immediately taken up by the liver parenchymal cells. There were only few grains over the Kupffer cells. 2 min to 6 h after the injection the highest specific radioactivity was in the free cholesterol fraction of the liver. The specific activity of liver esterified cholesterol was 54 % of that of the free cholesterol at 1 h. They both declined gradually and reached the same level in 1–2 days. There was a gradual rise of the specific activities of plasma free and esterified cholesterol starting 30 min after the injection. Both reached a maximum in 6–16 h, when the curve of plasma esterified cholesterol intersected that of liver esterified cholesterol. The radioactivity reappearing in plasma was associated with lipoproteins and red cells; the cholesterol of the high density lipoproteins had the highest specific activity. The results indicate that particulate cholesterol is taken up chiefly by the parenchymal cells of the liver and is subsequently incorporated into the plasma lipoproteins, most rapidly into the high density lipoproteins. A large fraction of plasma esterified cholesterol originates in th

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1977.tb05937.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

AbstractGlycogen synthetase (I + D) and phosphorylase (á+b) activity was determined in human skeletal muscle biopsies with different muscle fibre composition and in dissected and pooled batches of the two main muscle fibre types: slow twitch (ST) and fast twitch (FT), respectively. Glycogen synthetase (I + D) activity remained unchanged as the per cent of FT fibres increased, but phosphorylase (á+b) activity was found to increase. A similar activity pattern was found in dissected and pooled FT fibres as compared to ST fibres,i.e.the same glycogen synthetase activity but heightened phosphorylase activit

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1977.tb05938.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

AbstractBlood flow and tissue volume were recorded in the isolated canine subcutaneous adipose tissue, enclosed in a plethysmograph. Adrenaline and felypressin (oetapressin) were infused intra‐arterially at doses producing a blood flow reduction of approximately 60%. Adrenaline (4.6–23 ng/min) caused an initial reduction in tissue volume, indicating a constriction of capacitance vessels. Octapressin (0.46–9.2 ng/min) had no effect on tissue volume. Neither adrenaline or octapressin caused appreciable filtration or absorption, suggesting that the pre‐ to postcapillary resistance ratio remained unchanged. In contrast to sympathetic stimulation and noradrenaline, adrenaline significantly reduced the capillary filtration coefficient (CFC) by 34%, the change in CFC being related to the flow reductions, while octapressin did not reduce CFC significantly. On the basis of these results it is suggested that the constrictor effect of adrenaline on precapillary sphincter sections and on capacitance vessels is greater than that of octapressin in doses producing similar flow red

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1977.tb05939.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY