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- Karlmark, Bertil, et al.
(författare)
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Hans R Ulfendahl (1927-2021) : Obituary
- 2021
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Ingår i: Acta Physiologica. - : John Wiley & Sons. - 1748-1708 .- 1748-1716. ; 232:2
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Tidskriftsartikel (populärvet., debatt m.m.)
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| 2. |
- Broman, Lars Mikael, et al.
(författare)
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Effect of nitric oxide on renal autoregulation during hypothermia in the rat.
- 2017
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Ingår i: Pflügers Archiv. - : Springer Science and Business Media LLC. - 0031-6768 .- 1432-2013. ; 469:5-6, s. 669-680
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Tidskriftsartikel (refereegranskat)abstract
- Hypothermia-induced reduction of metabolic rate is accompanied by depression of both glomerular perfusion and filtration. The present study investigated whether these changes are linked to changes in renal autoregulation and nitric oxide (NO) signalling. During hypothermia, renal blood flow (RBF) and glomerular filtration rate (GFR) were reduced and urine production was increased, and this was linked with reduced plasma cGMP levels and increased renal vascular resistance. Although stimulation of NO production decreased vascular resistance, blood pressure and urine flow, intravenous infusion of the NO precursor L-arginine or the NO donor sodium nitroprusside did not alter RBF or GFR. In contrast, inhibition of NO synthesis by N(w)-nitro-L-arginine led to a further decline in both parameters. Functional renal autoregulation was apparent at both temperatures. Below the autoregulatory range, RBF in both cases increased in proportion to the perfusion ±pressure, although, the slope of the first ascending limb of the pressure-flow relationship was lower during hypothermia. The main difference was rather that the curves obtained during hypothermia levelled off already at a RBF of 3.9 ± 0.3 mL/min then remained stable throughout the autoregulatory pressure range, compared to 7.6 ± 0.3 mL/min during normothermia. This was found to be due to a threefold increase in, primarily, the afferent arteriolar resistance from 2.6 to 7.5 mmHg min mL(-1). Infusion of sodium nitroprusside did not significantly affect RBF during hypothermia, although a small increase at pressures below the autoregulatory range was observed. In conclusion, cold-induced rise in renal vascular resistance results from afferent arteriolar vasoconstriction by the autoregulatory mechanism, setting RBF and GFR in proportion to the metabolic rate, which cannot be explained by reduced NO production alone.
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| 3. |
- Ekstrand-Tobin, Annika, 1956-
(författare)
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Samband mellan astma och inomhusmiljö? : undersökning i 60 unga astmatikers bostäder
- 1993
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The objective of this cross-disciplinary project has been to find relationships between the indoor environment in the homes of 60 young asthmatics and their pattern of disease. The patients were selected by paediatric allergy specialists, who also made available the results of sensitisation tests and assessments of the severity of the patient's asthma.Field measurements were made in 60 homes during the winter of 1990/91, covering moisture, temperature, ventilation, volatile organic compounds (VOC), formaldehyde, carbon dioxide, radon and particles. In addition bacteria, endotoxins and microfungi in dust were also measured, and information was obtained concerning the families' lifestyle and their houses.The results show that ventilation air change rates per person were only about half of the aver age value for Swedish housing stock. Low ventilation tended to be linked to higher levels of various pollutants.The results, based on about 160 different parameters, do not show any simple relationship between the parameters which tend to describe the patients' condition in general terms and their indoor environment. What were revealed, however, were several interesting significant relationships between individual physical and medical parameters. Many of the results could be suitable as starting points for continued research, while others indicate ways in which the indoor environment could be improved in order to reduce the risk of development of allergies.
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| 9. |
- Rügheimer, Louise, et al.
(författare)
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Determination of the charge of the plasma proteins and consequent Donnan equilibrium across the capillary barriers in the rat microvasculature
- 2008
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Ingår i: Acta Physiologica. - : Wiley. - 1748-1708 .- 1748-1716. ; 194:4, s. 334-339
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Tidskriftsartikel (refereegranskat)abstract
- Aim Due to the negatively charged proteins in plasma, a Donnan equilibrium will be formed between plasma and interstitium or, as in the glomerulus, between glomerular plasma and Bowman's space. The phenomenon is of great physiological significance in the sense that the electro-osmotic pressure offered by the small ions attracted to the proteins may account for an important part of the total colloid osmotic pressure and also as the electric potential consequent to the Donnan distribution will affect the transcapillary transport of all charged molecular compounds. The present study aimed at estimating the protein charge in rat plasma in order to validate its importance for colloid osmotic pressure and potential. Methods The charge of the plasma proteins was determined in vitro from the concentration of sodium across a cellophane membrane separating a rat plasma sample from saline alone. However, in order to improve the sensitivity of the method, the studies were carried out at an ionic strength of 1/10 of physiological saline. Results The average charge of plasma was estimated at 0.23 +/- 0.003 mEq g(-1) protein (mean +/- SE), and the standard variation at +/- 0.01 mEq g(-1), i.e. about 5%. At the normal protein concentration in Wistar rats of 50 g L-1, the charge of the proteins in systemic plasma was calculated to be 11.5 mEq L-1, whereas in glomerular and peritubular capillary plasma, the larger protein concentration increases the protein charge to 14.4 mEq L-1. Conclusion The results verify that the plasma protein charge accounts for about one-third of the total colloid osmotic pressure and that the obtained potential will constitute a major driving force for the transport of charged molecular compounds.
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| 10. |
- Wolgast, Mats, et al.
(författare)
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The gel hypothesis applied to the rat renal capillary membranes - a review
- 2011
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Ingår i: Acta Physiologica. - : Wiley. - 1748-1708 .- 1748-1716. ; 202:4, s. 617-628
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Forskningsöversikt (refereegranskat)abstract
- In the gel model for the glomerular (and peritubular) capillary membrane, the integrity of the membrane is supposed to result from the fluid reabsorption induced by the osmotic action of the counter-ions attracted to negative fixed charges, increasing the gel pressure such that it becomes the same as in the capillaries. From this point on, the gel will be unaffected by the high capillary pressure. The same fluid reabsorption will also suspend the fibrils in the matrix such that they form a series of grids composed of, for example, horizontal fibrils spaced similarly from one another. The model thereby explains the well-known phenomenon of a uniform 'pore' size, although slits rather than pores constitute the transport routes. The model also explains the fact that the plasma proteins are free to move in the membrane matrix, which is the consequence of a recent finding that a major restriction to albumin is offered by a unique protein, nephrin, located between the podocytes in Bowman's space cells. A large molecule, which may become trapped in a slit between two fibrils, will thus push out the positive counter-ions whereby the charges become free and hence repel one another, widening the slit such that the molecule is free to move in any direction. It is furthermore concluded that the restriction to proteins is also dependent on the width of the slits closest to plasma.
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