| 1. |
- Martin-Boglind, Lene, et al.
(author)
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The effect of topical antiglaucoma drugs on the results of high-pass resolution perimetry
- 1991
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In: American Journal of Ophthalmology. - 0002-9394 .- 1879-1891. ; 11:6, s. 711-714
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Journal article (peer-reviewed)abstract
- We conducted a randomly assigned, double-masked, crossover study of the effects of betaxolol, epinephrine, pilocarpine, and timolol on the high-passresolution perimetry results in normal subjects. The influence of topical administration of these intraocular pressure reducing drugs was negligible, which confirmed the reliability of high-pass resolution perimetry results. The method seems appropriate for the diagnosis of glaucoma and the follow-up ofpatients with glaucoma.
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| 2. |
- Ekelund, Ulf, et al.
(author)
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In-vivo effects of endothelin-1 and ETA receptor blockade on arterial, venous and capillary functions in skeletal muscle
- 1993
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In: Acta Physiologica Scandinavica. - 0001-6772. ; 148:3, s. 273-283
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Journal article (peer-reviewed)abstract
- Results from in vitro studies have indicated that endothelin-1 is a main candidate for endothelium-derived contracting factors. The aim of this in vivo study was to describe in quantitative terms the effects of endothelin-1 (ET-1), and of ETA receptor blockade, on vascular tone (resistance) in large-bore arterial resistance vessels (> 25 microns), small arterioles (< 25 microns) and the veins, as well as on capillary pressure and fluid exchange in cat gastrocnemius muscle. Endothelin-1 (100-1600 ng kg-1 min-1, i.a.) elicited, after an initial transient dilation, a strong dose-dependent constrictor response in all three consecutive vascular sections, yet with a preferential action on the small arterioles and the veins. The vasoconstriction developed very slowly over about 1 h and was also long-lasting after cessation of the infusion. Our main quantitative analysis refers to effects elicited by 20 min long i.a. infusions of ET-1 at a dose of 400 ng kg-1 min-1. At the end of this period, the peptide caused, on average, a three-fold increase in total regional vascular resistance, in turn explained by a 70% increase in large-bore arterial resistance, a 280% increase in arteriolar resistance and a 220% increase in venous resistance. The latter effect was also manifested as a pronounced capacitance response, and as a decrease in the pre- to post-capillary resistance ratio leading regularly to a rise in capillary pressure, net transcapillary fluid filtration and oedema formation which is unusual for a vasoconstrictor. The new specific competitive ETA receptor antagonist FR 139317 was found to be fully effective in vivo, insofar as it abolished the constrictor response to endothelin-1. ETA receptor blockade, or administration of phosphoramidon, an inhibitor of ET-1 production, did not influence the level of basal vascular tone, indicating no significant endogenous release of ET-1 under resting conditions. This contrasts to the established pronounced endogenous release of endothelium-derived nitric oxide. Finally, vascular myogenic regulation was found not to be mediated by ET-1. The results, taken together, suggest a possible role of ET-1 in long-term, rather than short-term, regulation of vascular tone in vivo, perhaps especially during pathophysiological conditions.
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| 3. |
- Ekelund, Ulf, et al.
(author)
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Myogenic vascular regulation in skeletal muscle in vivo is not dependent of endothelium-derived nitric oxide
- 1992
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In: Acta Physiologica Scandinavica. - 0001-6772. ; 144:2, s. 199-207
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Journal article (peer-reviewed)abstract
- The hypothesis, based on in vitro experiments on large conduit arteries, that endothelium-derived nitric oxide is a mediator of vascular myogenic reactivity was tested in cat gastrocnemius muscle in vivo. This was done by comparing, in the absence and presence of effective endothelium-derived nitric oxide blockade by the specific inhibitors NG-monomethyl-L-arginine or NG-nitro-L-arginine methyl ester, myogenic responses in defined consecutive vascular sections to dynamic vascular transmural pressure stimuli, to arterial occlusion (reactive hyperaemia), and to arterial pressure changes (autoregulation of blood flow and capillary pressure). The results demonstrated that the myogenic vascular reactivity to quick ramp transmural pressure stimuli was not attenuated by endothelium-derived nitric oxide blockade, but rather reinforced. The amplitude of the reactive hyperaemia response was unaffected by endothelium-derived nitric oxide blockade, but its duration was shortened because of faster myogenic constriction, especially of large-bore arterial resistance vessels greater than 25 microns, in the recovery phase. Both the improved myogenic responsiveness to transmural pressure stimuli and the shortening of the reactive hyperaemia by endothelium-derived nitric oxide blockade suggested that endothelium-derived nitric oxide released in vivo acts as a 'metabolic' factor which certainly does not improve, but rather depresses myogenic vascular reactivity. Autoregulation of blood flow and capillary pressure were well preserved in the presence of endothelium-derived nitric oxide blockade. It was concluded from the results of these multifaceted tests that myogenic vascular regulation in skeletal muscle in vivo seems independent of endothelium-derived nitric oxide.(ABSTRACT TRUNCATED AT 250 WORDS)
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| 4. |
- Sonesson, Björn, et al.
(author)
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Sex difference in the mechanical properties of the abdominal aorta in human beings
- 1994
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In: Journal of Vascular Surgery. - 1097-6809. ; 20:6, s. 959-969
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Journal article (peer-reviewed)abstract
- PURPOSE: A previous study has shown age- and sex-related differences in abdominal aortic compliance. In that study blood pressure determined by auscultation in the brachial artery was assumed to be equal to blood pressure in the abdominal aorta. To validate our findings we investigated the pressure-diameter (P-D) relationship of the abdominal aorta. METHODS: Diameter and pulsatile diameter change of the abdominal aorta were determined noninvasively by an ultrasound phase-locked echo-tracking system with simultaneous measurement of aortic pressure resulting in P-D curves in 27 healthy male and female volunteers 23 to 72 years of age. The degree of error in aortic compliance as calculated from blood pressure determined by auscultation of the brachial artery rather than from direct measurement of aortic pressure was evaluated. Compliance was defined as the inverse of pressure strain elastic modulus (Ep) or of stiffness (beta). RESULTS: There was no significant difference in the systolic pressure at the two sites, but the diastolic pressure was systematically overestimated by approximately 10 mm Hg when determined by the auscultatory method (p < 0.01) leading to a 15% to 20% underestimation of Ep and stiffness (beta). The individual P-D curves exhibited hysteresis, were nonlinear, and revealed that the aorta is more distensible at lower than at higher pressures. The steepness of the P-D curve decreased with increasing age and this occurred at an earlier age in men than in women. CONCLUSION: This investigation demonstrates a decrease in abdominal aortic wall distensibility with age, which occurs at an earlier age in men, and confirms earlier results by use of the indexes Ep and stiffness (beta). This implies that the abdominal aorta in men is more prone to degenerative changes, which may be one of the factors responsible for the sex difference in aortic vascular disease.
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| 5. |
- Lindberg, Lars, et al.
(author)
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Nitric oxide gives maximal response after coronary artery bypass surgery
- 1994
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In: Journal of Cardiothoracic and Vascular Anesthesia. - : Elsevier BV. - 1532-8422 .- 1053-0770. ; 8:2, s. 182-187
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Journal article (peer-reviewed)abstract
- The dose-response to inhalation of nitric oxide (NO) after coronary artery bypass surgery was studied in seven patients with normal preoperative lung function and chest radiograms. During postoperative controlled ventilation with PEEP 5 and 10 cmH2O, the patients inhaled NO in concentrations of 2 to 25 ppm, in random order, for 6 to 10 minutes. Hemodynamic and oximetric data were analyzed before, 5 minutes after start of the NO inhalation, and 5 minutes after the cessation. The response was the same at all concentrations; mean pulmonary artery pressure decreased by 11 +/- 1% (P < 0.05) and pulmonary vascular resistance decreased by 22 +/- 2% (P < 0.05). Systemic hemodynamics did not change, but oximetric parameters tended to improve. Changes in PEEP did not affect the response. It is concluded that, in patients who have undergone coronary artery bypass grafting, inhalation of 2 to 25 ppm NO causes a dose-independent decrease in pulmonary artery pressure and pulmonary vascular resistance. In order to investigate the dose-response curve, concentrations lower than 2 ppm of NO must be used.
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| 6. |
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| 7. |
- Åkeson, Jonas, et al.
(author)
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Aspiration av alifatiska kolväten kan ge livshotande lungpåverkan hos småbarn
- 1990
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In: Läkartidningen. - 0023-7205. ; 87:51-52, s. 4420-4423
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Journal article (peer-reviewed)abstract
- Ingestion of aliphatic hydrocarbons--even in small amounts--can cause severe respiratory distress in children. Such accidents are becoming increasingly common in Sweden. A case of severe hydrocarbon ingestion is reported, where a 16-month-old boy, initially treated with mechanical ventilation for respiratory distress, subsequently developed a reversible radiological complication, pneumatocele. Patients at risk of severe hydrocarbon intoxication can be identified by careful evaluation of their history and continuous clinical observation. Controlled ventilation should be instituted early in respiratory distress, and any radiological changes followed up in a few weeks.
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| 8. |
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| 9. |
- Bergqvist, D, et al.
(author)
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Low molecular weight heparin for thromboprophylaxis and epidural/spinal anaesthesia--is there a risk?
- 1992
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In: Acta Anaesthesiologica Scandinavica. - 0001-5172. ; 36:7, s. 605-609
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Journal article (peer-reviewed)abstract
- This article reviews the problem of bleeding in connection with epidural/spinal anaesthesia, with special emphasis on the use of low molecular weight heparins for thromboprophylaxis. There are methodological difficulties to studying the problem in a scientifically correct way because of the rarity of the complication. However, from the data in the literature there are no indications of an increased risk in using the combination of low molecular weight heparin in prophylactic doses and epidural/spinal anaesthesia. So far, there is only a single case report, of spinal haematoma, although low molecular weight heparins have been used in combination with epidural/spinal anaesthesia in at least 1,000,000 patients. In controlled studies, at least 10,000 patients have been given the combination without complications.
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| 10. |
- Bjorkman, S, et al.
(author)
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The effect of thiopental on cerebral blood flow, and its relation to plasma concentration, during simulated induction of anaesthesia in a porcine model
- 1994
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In: Acta Anaesthesiologica Scandinavica. - 0001-5172. ; 38:5, s. 473-478
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Journal article (peer-reviewed)abstract
- The reversible effect of an induction dose of thiopental on the cerebral blood flow (CBF) was characterized by repeated 133Xe washout measurements during stable physiological conditions in anaesthetized pigs. A thiopental effect corresponding to induction of light and transient anaesthesia was confirmed by electroencephalography (EEG). The concentration (arterial plasma) -effect (-% CBF) relationship of thiopental was estimated using a sigmoidal Emax model. The injection caused a rapid 36 +/- 4.5% (mean +/- s.d.) drop in CBF, with return to baseline by 80 min. According to the pharmacodynamic model, the maximal effect of thiopental (Emax) in this experimental set-up was a 58% lowering of the CBF and the concentration at half-maximal effect (EC50) was 25 micrograms.ml-1. This study provides a complete characterization of the effect of thiopental on the CBF, including the time-course and concentration-effect relationship. A comparison to limited data in the literature suggests that the findings in the pigs constitute a fair approximation of the action of thiopental during the clinical induction of anaesthesia.
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