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| 2. |
- Arner, Anders, et al.
(författare)
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Smooth, slow and smart muscle motors.
- 2003
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Ingår i: Journal of Muscle Research and Cell Motility. - 0142-4319. ; 24:2-3, s. 165-173
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Tidskriftsartikel (refereegranskat)abstract
- Smooth muscle is a slow and economical muscle with a large variability in contractile properties. This review describes results regarding the relation between expression of myosin isoforms and the contraction of smooth muscle. The focus of the review is on studies of the organised contractile system in the smooth muscle tissue. The role of the myosin heavy chain variants formed by alternative splicing in the myosin heavy chain tail (SM1, SM2 isoforms) and head (SM-A SM-B isoforms) regions, as well as the role of essential light chains (LC17a, LC17b isoforms) for the variability of contractile properties are discussed. Smooth muscle also has the ability to alter its contractile properties in response to altered functional demands in vivo, e.g. during hypertrophic growth of urinary bladder, intestine, uterus and vessels and in response to altered hormone levels. These alterations involve changes in myosin expression and altered contractile kinetics. Non-muscle myosin has been shown to have a contractile function in some smooth muscle tissues and recent data on the kinetic properties of non-muscle myosin filaments in smooth muscle tissue are described.
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| 3. |
- Karlsson Wede, Oskar, et al.
(författare)
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Mechanical function of intermediate filaments in arteries of different size examined using desmin deficient mice.
- 2002
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Ingår i: Journal of Physiology. - : Wiley. - 1469-7793 .- 0022-3751. ; 540:Pt 3, s. 941-949
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Tidskriftsartikel (refereegranskat)abstract
- Protein composition and mechanical function of intermediate filaments were examined in arteries of different sizes using desmin deficient mice (Des-/-) and their wild-type controls (Des+/+). Using SDS-PAGE gels and Western blots we found a gradient in desmin expression in the arterial tree; the desmin content increased from the elastic artery aorta, via the muscular mesenteric artery to the resistance-sized mesenteric microarteries approximately 150 microm in diameter in Des+/+ mice. Mechanical experiments were performed on the aorta, the mesenteric artery and resistance-sized arteries using wire myographs. For aorta and mesenteric artery, no differences in passive or active circumference- stress relations were found between Des-/- and Des+/+ mice. In microarteries, both passive and active stress were lower in the Des-/- group. In conclusion, large elastic and muscular arteries contain a relatively low amount of desmin, and the desmin intermediate filaments do not seem to play a major role in the mechanical properties of these larger arterial vessels. In the microarteries, where expression of desmin is high, desmin plays a role in supporting both passive and active tension.
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| 4. |
- Kolak, Mia, et al.
(författare)
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Immigrant women's perspectives on contraceptive counselling provided by midwives in Sweden - a qualitative study
- 2022
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Ingår i: Sexual and reproductive health matters. - : Taylor & Francis. - 2641-0397. ; 30:1
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Tidskriftsartikel (refereegranskat)abstract
- Immigrant women in Sweden often have unmet sexual and reproductive health (SRH) needs. Successful contraceptive counselling may improve their sexual and reproductive health and rights. The unique Swedish model, with midwives as the main providers of contraceptive counselling, is important for immigrant women's health at both individual and societal levels. This study explored immigrant women's perspectives on receiving contraceptive counselling from midwives in Sweden, in order to obtain deeper knowledge about the factors they perceive as important in the counselling situation. Nineteen in-depth individual interviews were conducted from December 2018 to February 2019, followed by qualitative manifest and latent content analysis. Trust emerged as the overall important factor in the contraceptive counselling meeting. Knowledge was lacking about the midwife's professional role as a contraceptive counsellor. Contraceptive counselling was seen as a private matter not easily shared with unfamiliar midwives or interpreters. Previous experiences of contraceptives and preconceptions were important considerations for contraceptive choice, but communicating these needs required trust. Women also wanted more knowledge about contraceptives and SRH care and rights. Cultural and social norms concerning when and why to use contraceptives needed to be acknowledged in the midwife encounter. Although immigrant women want more knowledge about contraception, a trustful relationship with the midwife is needed to be able to make informed contraceptive choices. Midwives may need increased awareness of the many factors influencing immigrant women's choices to ensure their contraceptive autonomy. Policy changes that promote new ways of counselling and ability to provide continuous care are needed.
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| 5. |
- Löfgren, Mia, et al.
(författare)
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Effects of thyroxine on myosin isoform expression and mechanical properties in guinea-pig smooth muscle.
- 2002
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Ingår i: Journal of Physiology. - : Wiley. - 1469-7793 .- 0022-3751. ; 543:3, s. 757-766
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Tidskriftsartikel (refereegranskat)abstract
- Information on the effects of thyroid hormone on smooth muscle contractile protein expression and mechanical properties is sparse. We have addressed the following questions. (1) Can thyroxine hormone alter myosin isoform composition in smooth muscle? (2) Can a change in myosin isoform composition lead to altered mechanical properties in smooth muscle? (3) Are alterations, if occurring, equal in fast and slow smooth muscle types? Guinea-pigs were treated with thyroxine (T(4)) for 12 days. Control animals were given physiological saline solution. Maximal unloaded shortening velocity (V(max)) was measured in chemically skinned, maximally activated muscle preparations from the aorta and the taenia coli. V(max) increased following thyroxine treatment, by approximately 20 % in the taenia coli. In the aorta, no significant increase in V(max) could be detected. The sensitivity of isometric force to inorganic phosphate (P(i)) was increased in the taenia coli following thyroxine treatment. The expression of mRNA (determined with RT-PCR) for the myosin heavy chain with the seven amino acid insert increased by approximately 70 % in the aorta and about 25 % in the taenia coli following thyroxine treatment. Western blot analysis showed an increase in the inserted myosin heavy chain form in the taenia coli. Expression of mRNA for the myosin essential light chains and the corresponding proteins did not change significantly in either muscle type. No alterations in non-muscle myosin heavy chain isoforms could be detected after thyroxine treatment. In conclusion, thyroxine treatment alters the isoform composition of myosin in fast and slow smooth muscles in vivo. This change is sufficient to increase shortening velocity and sensitivity of isometric force to P(i) in the fast, but not in the slow, smooth muscle type.
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| 6. |
- Löfgren, Mia, et al.
(författare)
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Nonmuscle Myosin motor of smooth muscle.
- 2003
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Ingår i: Journal of General Physiology. - : Rockefeller University Press. - 0022-1295 .- 1540-7748. ; 121:4, s. 301-310
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Tidskriftsartikel (refereegranskat)abstract
- Nonmuscle myosin can generate force and shortening in smooth muscle, as revealed by studies of the urinary bladder from mice lacking smooth muscle myosin heavy chain (SM-MHC) but expressing the nonmuscle myosin heavy chains A and B (NM-MHC A and B; Morano, I., G.X. Chai, L.G. Baltas, V. Lamounier-Zepter, G. Lutsch, M. Kott, H. Haase, and M. Bader. 2000. Nat. Cell Biol. 2:371–375). Intracellular calcium was measured in urinary bladders from SM-MHC–deficient and SM-MHC–expressing mice in relaxed and contracted states. Similar intracellular [Ca2+] transients were observed in the two types of preparations, although the contraction of SM-MHC–deficient bladders was slow and lacked an initial peak in force. The difference in contraction kinetics thus do not reflect differences in calcium handling. Thick filaments were identified with electron microscopy in smooth muscle cells of SM-MHC–deficient bladders, showing that NM-MHC can form filaments in smooth muscle cells. Maximal shortening velocity of maximally activated, skinned smooth muscle preparations from SM-MHC–deficient mice was significantly lower and more sensitive to increased MgADP compared with velocity of SM-MHC–expressing preparations. Active force was significantly lower and less inhibited by increased inorganic phosphate. In conclusion, large differences in nucleotide and phosphate binding exist between smooth and nonmuscle myosins. High ADP binding and low phosphate dependence of nonmuscle myosin would influence both velocity of actin translocation and force generation to promote slow motility and economical force maintenance of the cell.
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| 7. |
- Löfgren, Mia, et al.
(författare)
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Substrate and product dependence of force and shortening in fast and slow smooth muscle
- 2001
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Ingår i: Journal of General Physiology. - : Rockefeller University Press. - 0022-1295 .- 1540-7748. ; 117:5, s. 407-418
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Tidskriftsartikel (refereegranskat)abstract
- To explore the molecular mechanisms responsible for the variation in smooth muscle contractile kinetics, the influence of MgATP, MgADP, and inorganic phosphate (P(i)) on force and shortening velocity in thiophosphorylated "fast" (taenia coli: maximal shortening velocity Vmax = 0.11 ML/s) and "slow" (aorta: Vmax = 0.015 ML/s) smooth muscle from the guinea pig were compared. P(i) inhibited active force with minor effects on the V(max). In the taenia coli, 20 mM P(i) inhibited force by 25%. In the aorta, the effect was markedly less (< 10%), suggesting differences between fast and slow smooth muscles in the binding of P(i) or in the relative population of P(i) binding states during cycling. Lowering of MgATP reduced force and V(max). The aorta was less sensitive to reduction in MgATP (Km for Vmax: 80 microM) than the taenia coli (Km for Vmax: 350 microM). Thus, velocity is controlled by steps preceding the ATP binding and cross-bridge dissociation, and a weaker binding of ATP is not responsible for the lower V(max) in the slow muscle. MgADP inhibited force and V(max). Saturating concentrations of ADP did not completely inhibit maximal shortening velocity. The effect of ADP on Vmax was observed at lower concentrations in the aorta compared with the taenia coli, suggesting that the ADP binding to phosphorylated and cycling cross-bridges is stronger in slow compared with fast smooth muscle.
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| 8. |
- Löfgren, Mia
(författare)
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Variability and adaptation in the contractile system of smooth muscle
- 2002
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis examines the cellular and molecular mechanisms involved in the large diversity of the contractile properties in smooth muscle. Six studies, I-VI, are included. I: a slow smooth muscle (aorta) has a different nucleotide and phosphate dependence compared to a fast type (taenia coli). A slow ADP-release can be one mechanism responsible for the lower shortening velocity of aorta. II: treatment with thyroid hormone in vivo leads to a change in the myosin isoform composition, higher shortening velocity and altered sensitivity to phosphate in smooth muscle. III: hypertrophying intestinal smooth muscle has lower shortening velocity, higher sensitivity to ADP and altered myosin isoform composition compared to normal tissue. IV: calcium transients were similar for smooth muscle tissues with non-muscle and smooth muscle myosin. In fully activated, permeabilised preparations, the sensitivity to ADP was higher for non-muscle compared to smooth muscle myosin, suggesting that a slower ADP-release might be an explanation for the low velocity of non-muscle myosins. The isometric force of non-muscle myosin was much less inhibited by phosphate. V: expression of the intermediate filament protein desmin increased with decreasing size in the arterial tree, down to microarteries. Desmin has a role in active and passive tension development in the microarteries, but not in the aorta or the mesenteric artery. VI: a novel in vitro knock-out technique to remove beta1-integrin in smooth muscle tissue was introduced. Beta1-integrin depletion leads to decreased active force, suggesting a role for beta1-integrin in force generation, or in the maintenance of a contractile phenotype.
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| 9. |
- Löfgren, Orvar, et al.
(författare)
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Framtidskuster : efterord
- 2013
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Ingår i: Framtidskuster : hållbar utveckling i kustsamhällen. - 9789170611308 ; , s. 305-313
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Bokkapitel (refereegranskat)
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| 10. |
- van Buggenhout, Sandra, et al.
(författare)
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Structural design of natural plant based foods to promote nutritional quality
- 2012
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Ingår i: Trends in Food Science and Technology. - : Elsevier BV. - 0924-2244 .- 1879-3053. ; 24:1, s. 47-59
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- During traditional industrial processing of fruit and vegetable derived foods, consideration of the eventual retention, bio-accessibility or bio-availability of nutrients has hitherto been a secondary priority. Indeed standard processing of soups and sauces involves treating all ingredients in a similar way, usually by prolonged heat treatment and results in both lowered nutritional value and sensory quality of food products. Such products are typically structured using various additives including starches, gums and stabilizers, which consumers regard as unnatural, rather than exploiting the endogenous structuring potential of the fruit and vegetable ingredients as available at the farm gate. Recent studies undertaken within the EU sponsored 'Healthy Structuring' project have shown how to design an industrially manufactured product with good sensory qualities that is natural and nutritious. The strategy has been to use the inherent structural and nutritional properties of the raw material ingredients, on the one hand to ensure the textural quality of the final product without the use of artificial gums or stabilizers and, on the other hand to optimize the nutritional quality of the final product. This review briefly summarizes both the approach taken and the results obtained within the project.
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