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| 3. |
- Sigmundsson, F., et al.
(författare)
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Segmented lateral dyke growth in a rifting event at Bardarbunga volcanic system, Iceland
- 2015
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 517:7533
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Tidskriftsartikel (refereegranskat)abstract
- Crust at many divergent plate boundaries forms primarily by the injection of vertical sheet-like dykes, some tens of kilometres long(1). Previous models of rifting events indicate either lateral dyke growth away from a feeding source, with propagation rates decreasing as the dyke lengthens(2-4), or magma flowing vertically into dykes from an underlying source(5,6), with the role of topography on the evolution of lateral dykes not clear. Here we show how a recent segmented dyke intrusion in the Bardarbunga volcanic system grew laterally for more than 45 kilometres at a variable rate, with topography influencing the direction of propagation. Barriers at the ends of each segment were overcome by the build-up of pressure in the dyke end; then a new segment formed and dyke lengthening temporarily peaked. The dyke evolution, which occurred primarily over 14 days, was revealed by propagating seismicity, ground deformation mapped by Global Positioning System(GPS), interferometric analysis of satellite radar images (InSAR), and graben formation. The strike of the dyke segments varies from an initially radial direction away from the Bardarbunga caldera, towards alignment with that expected from regional stress at the distal end. A model minimizing the combined strain and gravitational potential energy explains the propagation path. Dyke opening and seismicity focused at the most distal segment at any given time, and were simultaneous with magma source deflation and slow collapse at the Bardarbunga caldera, accompanied by a series of magnitude M > 5 earthquakes. Dyke growth was slowed down by an effusive fissure eruption near the end of the dyke. Lateral dyke growth with segment barrier breaking by pressure build-up in the dyke distal end explains how focused upwelling of magma under central volcanoes is effectively redistributed over long distances to create new upper crust at divergent plate boundaries.
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| 4. |
- Ahlström, Aisling, 1976, et al.
(författare)
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A double-blind randomized controlled trial investigating a time-lapse algorithm for selecting Day 5 blastocysts for transfer
- 2022
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Ingår i: Human Reproduction. - : Oxford University Press (OUP). - 0268-1161 .- 1460-2350. ; 37:4, s. 708-717
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Tidskriftsartikel (refereegranskat)abstract
- STUDY QUESTION Can use of a commercially available time-lapse algorithm for Day 5 blastocyst selection improve pregnancy rates compared with morphology alone? SUMMARY ANSWER The use of a time-lapse selection model to choose blastocysts for fresh single embryo transfer on Day 5 did not improve ongoing pregnancy rate compared to morphology alone. WHAT IS KNOWN ALREADY Evidence from time-lapse monitoring suggests correlations between timing of key developmental events and embryo viability. No good quality evidence exists to support improved pregnancy rates following time-lapse selection. STUDY DESIGN, SIZE, DURATION A prospective multicenter randomized controlled trial including 776 randomized patients was performed between 2018 and 2021. Patients with at least two good quality blastocysts on Day 5 were allocated by a computer randomization program in a proportion of 1:1 into either the control group, whereby single blastocysts were selected for transfer by morphology alone, or the intervention group whereby final selection was decided by a commercially available time-lapse model. The embryologists at the time of blastocyst morphological scoring were blinded to which study group the patients would be randomized, and the physician and patients were blind to which group they were allocated until after the primary outcome was known. The primary outcome was number of ongoing pregnancies in the two groups. PARTICIPANTS/MATERIALS, SETTING, METHODS From 10 Nordic IVF clinics, 776 patients with a minimum of two good quality blastocysts on Day 5 (D5) were randomized into one of the two study groups. A commercial time-lapse model decided the final selection of blastocysts for 387 patients in the intervention (time-lapse) group, and blastocysts with the highest morphological score were transferred for 389 patients in the control group. Only single embryo transfers in fresh cycles were performed. MAIN RESULTS AND THE ROLE OF CHANCE In the full analysis set, the ongoing pregnancy rate for the time-lapse group was 47.4% (175/369) and 48.1% (181/376) in the control group. No statistically significant difference was found between the two groups: mean difference -0.7% (95% CI -8.2, 6.7, P = 0.90). Pregnancy rate (60.2% versus 59.0%, mean difference 1.1%, 95% CI -6.2, 8.4, P = 0.81) and early pregnancy loss (21.2% versus 18.5%, mean difference 2.7%, 95% CI -5.2, 10.6, P = 0.55) were the same for the time-lapse and the control group. Subgroup analyses showed that patient and treatment characteristics did not significantly affect the commercial time-lapse model D5 performance. In the time-lapse group, the choice of best blastocyst changed on 42% of occasions (154/369, 95% CI 36.9, 47.2) after the algorithm was applied, and this rate was similar for most treatment clinics. LIMITATIONS, REASONS FOR CAUTION During 2020, the patient recruitment rate slowed down at participating clinics owing to coronavirus disease-19 restrictions, so the target sample size was not achieved as planned and it was decided to stop the trial prematurely. The study only investigated embryo selection at the blastocyst stage on D5 in fresh IVF transfer cycles. In addition, only blastocysts of good morphological quality were considered for transfer, limiting the number of embryos for selection in both groups: also, it could be argued that this manual preselection of blastocysts limits the theoretical selection power of time-lapse, as well as restricting the results mainly to a good prognosis patient group. Most patients were aimed for blastocyst stage transfer when a minimum of five zygotes were available for extended culture. Finally, the primary clinical outcome evaluated was pregnancy to only 6-8 weeks. WIDER IMPLICATIONS OF THE FINDINGS The study suggests that time-lapse selection with a commercially available time-lapse model does not increase chance of ongoing pregnancy after single blastocyst transfer on Day 5 compared to morphology alone. STUDY FUNDING/COMPETING INTEREST(S) The study was financed by a grant from the Swedish state under the ALF-agreement between the Swedish government and the county councils (ALFGBG-723141). Vitrolife supported the study with embryo culture dishes and culture media. During the study period, T.H. changed his employment from Livio AB to Vitrolife AB. All other authors have no conflicts of interests to disclose. DATE OF FIRST PATIENT'S ENROLMENT 11 June 2018.
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| 5. |
- Geirsson, H., et al.
(författare)
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Overview of results from continuous GPS observations in Iceland from 1995 to 2010
- 2010
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Ingår i: Jökull. - 0449-0576. ; 60:1, s. 1-21
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Tidskriftsartikel (refereegranskat)abstract
- Iceland is a natural laboratory for a variety of processes associated with crustal deformation, such as earthquakes, magmatic events, tectonic plate motions, and glacial load changes. Continuous GPS (CGPS) measurements started in Iceland in 1995, and since then data from the network have helped to shed light on many different active deformation processes. The number of CGPS sites in Iceland tripled during 2006–2008, as a result of an international collaborative effort coordinated by Icelandic scientists. By early 2010 the number of CGPS stations in Iceland had reached 64, located primarily around and within the North- American–Eurasian plate boundary zone. Since its initiation, the CGPS network has played an important role in monitoring volcanoes and seismogenic areas, most notably during the 2009–2010 Eyjafjallajökull volcano unrest. Plate spreading of up to 2 cm per year usually dominates the horizontal motion observed at the CGPS sites, while uplift is observed at many of the stations due to recent retreat of the Icelandic ice caps. Co-seismic and post-seismic deformation of the largest earthquakes in 2000 and 2008 in the South Iceland Seismic Zone were captured by the network, and high-rate (1 Hz) CGPS observations helped to identify two magnitude 6 mainshocks in 2008 that were separated in time by only 2–3 seconds. The CGPS network has thus enabled us to monitor deformation occurring over days to months caused by migration of magma or fluids, post-seismic transients, rapid deformation caused by earthquakes and eruptions, as well as the long term plate spreading signal.
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| 18. |
- Rodríguez-Varela, Ricardo, et al.
(författare)
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The genetic history of Scandinavia from the Roman Iron Age to the present
- 2023
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Ingår i: Cell. - : Elsevier. - 0092-8674 .- 1097-4172. ; 186:1, s. 32-46
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Tidskriftsartikel (refereegranskat)abstract
- We investigate a 2,000-year genetic transect through Scandinavia spanning the Iron Age to the present, based on 48 new and 249 published ancient genomes and genotypes from 16,638 modern individuals. We find regional variation in the timing and magnitude of gene flow from three sources: the eastern Baltic, the British-Irish Isles, and southern Europe. British-Irish ancestry was widespread in Scandinavia from the Viking period, whereas eastern Baltic ancestry is more localized to Gotland and central Sweden. In some regions, a drop in current levels of external ancestry suggests that ancient immigrants contributed proportionately less to the modern Scandinavian gene pool than indicated by the ancestry of genomes from the Viking and Medieval periods. Finally, we show that a north-south genetic cline that characterizes modern Scandinavians is mainly due to the differential levels of Uralic ancestry and that this cline existed in the Viking Age and possibly earlier.
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| 19. |
- Sanyal, S, et al.
(författare)
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Involvement of corepressor complex subunit GPS2 in transcriptional pathways governing human bile acid biosynthesis
- 2007
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424. ; 104:40, s. 15665-15670
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Tidskriftsartikel (refereegranskat)abstract
- Coordinated regulation of bile acid biosynthesis, the predominant pathway for hepatic cholesterol catabolism, is mediated by few key nuclear receptors including the orphan receptors liver receptor homolog 1 (LRH-1), hepatocyte nuclear factor 4α (HNF4α), small heterodimer partner (SHP), and the bile acid receptor FXR (farnesoid X receptor). Activation of FXR initiates a feedback regulatory loop via induction of SHP, which suppresses LRH-1- and HNF4α-dependent expression of cholesterol 7α hydroxylase (CYP7A1) and sterol 12α hydroxylase (CYP8B1), the two major pathway enzymes. Here we dissect the transcriptional network governing bile acid biosynthesis in human liver by identifying GPS2, a stoichiometric subunit of a conserved corepressor complex, as a differential coregulator of CYP7A1 and CYP8B1 expression. Direct interactions of GPS2 with SHP, LRH-1, HNF4α, and FXR indicate alternative coregulator recruitment strategies to cause differential transcriptional outcomes. In addition, species-specific differences in the regulation of bile acid biosynthesis were uncovered by identifying human CYP8B1 as a direct FXR target gene, which has implications for therapeutic approaches in bile acid-related human disorders.
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| 20. |
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| 21. |
- Skuladottir, AT, et al.
(författare)
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A genome-wide meta-analysis identifies 50 genetic loci associated with carpal tunnel syndrome
- 2022
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Ingår i: Nature communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 13:1, s. 1598-
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Tidskriftsartikel (refereegranskat)abstract
- Carpal tunnel syndrome (CTS) is the most common entrapment neuropathy and has a largely unknown underlying biology. In a genome-wide association study of CTS (48,843 cases and 1,190,837 controls), we found 53 sequence variants at 50 loci associated with the syndrome. The most significant association is with a missense variant (p.Glu366Lys) in SERPINA1 that protects against CTS (P = 2.9 × 10−24, OR = 0.76). Through various functional analyses, we conclude that at least 22 genes mediate CTS risk and highlight the role of 19 CTS variants in the biology of the extracellular matrix. We show that the genetic component to the risk is higher in bilateral/recurrent/persistent cases than nonrecurrent/nonpersistent cases. Anthropometric traits including height and BMI are genetically correlated with CTS, in addition to early hormonal-replacement therapy, osteoarthritis, and restlessness. Our findings suggest that the components of the extracellular matrix play a key role in the pathogenesis of CTS.
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| 25. |
- Andersson, L-O, et al.
(författare)
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A new neutron beam facility
- 2004
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Ingår i: Proc. of the 9th European Particle Accelerator Conference.
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Konferensbidrag (refereegranskat)
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| 26. |
- Borgfeldt, Christer, et al.
(författare)
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High tumor tissue concentration of urokinase plasminogen activator receptor is associated with good prognosis in patients with ovarian cancer
- 2003
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Ingår i: International Journal of Cancer. - : Wiley. - 0020-7136. ; 107:4, s. 658-665
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Tidskriftsartikel (refereegranskat)abstract
- volved in tumor growth and metastasis. We assayed the components of the uPA system in homogenates of 64 primary epithelial ovarian tumors and 5 metastases and evaluated the association of these parameters to prognosis in the 51 malignant cases. The levels of uPA, PAI-2 and the uPA: PAI-I complex increased with progressive loss of histological differentiation (P-trend <0.001, <0.05 and <0.001). The level of PAI-I was higher in poorly than in well/moderately differentiated tumors (p = 0.03). The content of uPAR was lower in benign tumors as compared to borderline malignancies (p = 0.002), invasive primary tumors (p < 0.001), and metastases (p = 0.002). Surprisingly, the level of uPAR was lower in poorly differentiated as compared to both borderline (p = 0.01) and well differentiated malignant tumors (p = 0.005). Also, the level of uPAR was lower in advanced as compared to early stages of the disease (P-trend = 0.002). The median follow-up time for patients was 5.8 years. High tumor tissue levels of uPAR were associated with longer postoperative survival (HR = 0.4, 95% CI = 0.2-0.8, p = 0.01). In contrast, shorter survival was evident in patients with high tumor levels of uPA from 2 years on after operation (HR = 4.6, 95% CI = 1.2-17, p = 0.02). High tPA levels tended to be associated with shorter overall survival after 2 years (HR = 2.9, 95% 95% Cl = 0.9-9.8, p = 0.08). Although high tumor tissue content of uPAR was associated with a less aggressive phenotype characterized by well differentiated histology and longer survival, low content of uPAR in the poorly differentiated tumors and metastases presumably results from increased elimination of uPAR. (C) 2003 Wiley-Liss, Inc.
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| 27. |
- Brandt, Y., et al.
(författare)
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Effects of ACTH injections during estrus on concentrations and patterns of progesterone, estradiol, LH, and inhibin alpha and time of ovulation in the sow
- 2007
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Ingår i: Domestic Animal Endocrinology. - : Elsevier. - 0739-7240 .- 1879-0054. ; 32:2, s. 122-137
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Tidskriftsartikel (refereegranskat)abstract
- This study investigated whether injections of ACTH for 48 h, from the onset of the second standing estrus after weaning, had any impact on time of ovulation and patterns of progesterone, estradiol, luteinizing hormone (LH), and inhibin a. The studied sows (n = 15) were fitted with jugular vein catheters and randomly divided into a control (C group) and an ACTH group. From the onset of standing estrus, the sows were injected (NaCl or synthetic ACTH, 5 mu g/kg) every 4 h; blood samples were collected immediately before and 45 min after each injection. Ovulation was monitored using ultrasonography. The ACTH-group sows stopped displaying signs of standing estrus sooner after ovulation in their second estrus, but no impact was found on time of ovulation. There were no significant differences in the intervals between LH peak, estradiol peak, and the onset of standing estrus between the C and ACTH groups. The cortisol and progesterone concentrations were significantly elevated (p less than 0.001) in samples taken 45 min after ACTH injection. There were minor differences in estradiol and LH concentrations between the groups. Overall inhibin a concentrations were significantly higher during the treatment period in the ACTH than in the C group, but there were no significant differences between samples taken either 45 min or 4h after injection. In conclusion, injections of synthetic ACTH during estrus in the sow apparently disturb the duration of signs of standing estrus and the hormonal pattern of progesterone, and possibly of inhibin ot, estradiol and LH. (c) 2006 Elsevier Inc. All rights reserved.
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| 28. |
- Brandt, Y., et al.
(författare)
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Effects of exogenous ACTH during oestrus on early embryo development and oviductal transport in the sow
- 2007
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Ingår i: Reproduction in domestic animals. - : Wiley-Blackwell. - 0936-6768 .- 1439-0531. ; 42:2, s. 118-125
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Tidskriftsartikel (refereegranskat)abstract
- This study was conducted to assess the effects of ACTH injections on the early development of embryos and their transportation to the uterus. Fifteen sows were monitored for ovulation using transrectal ultrasonography during the first two oestrous periods after weaning. The sows were randomly divided into a control group (C group, n = 8) and an ACTH-treated group (ACTH group, n = 7), and were all surgically fitted with intra-jugular catheters. From the onset of the second standing oestrus after weaning, the sows were injected (NaCl/synthetic ACTH) every 4 h. Blood samples were collected immediately before and 45 min after each injection. All sows were inseminated once 10-33 h before ovulation in their second oestrus after weaning. At 48 (n = 4) or 60 (n = 11) h after ovulation during their second oestrus, the sows were killed and the embryos retrieved from the oviduct and uterus. The embryos were counted and compared with the number of corpora lutea, cleavage rate was noted and, finally, the embryos were prepared for confocal laser scanning microscopy and transmission electron microscopy. There was no difference between the groups regarding cleavage rate, the cytoskeleton, or the number of active nucleoli. However, the ACTH group had significantly (p less than 0.05) fewer ova/embryos retrieved (51%) than the C group (81%), and there was a tendency towards faster transportation to the uterus in the ACTH group, possibly because of high progesterone concentrations during treatment. To conclude, administration of ACTH every 4 h from onset of oestrus to 48 h caused significant loss of oocytes or embryos, and possibly faster transportation through the oviduct.
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| 29. |
- Brandt, Y, et al.
(författare)
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Impact of ACTH administration on the oviductal sperm reservoir in sows: The local endocrine environment and distribution of spermatozoa
- 2006
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Ingår i: Animal Reproduction Science. - : Elsevier Masson. - 0378-4320 .- 1873-2232. ; 92:1-2, s. 107-122
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Tidskriftsartikel (refereegranskat)abstract
- The objective of the study was to investigate if short-term stress in sows (simulated by injections of synthetic adrenocorticotrophic hormone (ACTH)) during standing oestrus had a negative effect on the local environment in the utero-tubal junction (UTJ) and isthmus and the distribution of spermatozoa in these segments. Fourteen sows were monitored for ovulation using ultrasonography in two consecutive oestruses. The sows were fitted with jugular catheters and, from onset of the second oestrus, blood samples were collected every second hour. In the 2nd oestrus, seven sows were given ACTH every second hour, from the onset of standing oestrus until the sow ovulated (ACTH-group), whereas the other seven sows remained as controls (C-group) and were given NaCl solution. The sows were artificially inseminated 16-18 h before expected ovulation. Six hours after ovulation the sows were anaesthetised, and blood samples were repeatedly taken from veins draining the uterus and the UTJ-isthmus, respectively. This oviduct was thereafter removed and divided in four adjacent sections consisting of: (i) the UTJ, (ii) the first, and (iii) the second isthmus segment prior to (iv), the ampullary-isthmic junction (AIJ) and the ampulla. The three first-mentioned segments were flushed to retrieve spermatozoa, whereas the last one was flushed to collect oocytes/ova. The number of spermatozoa attached to the zona pellucida was counted. The concentrations of cortisol in jugular blood of the ACTH-group sows during the time of ACTH-injections were significantly higher than of the C-group sows (p less than 0.05), as were the levels of progesterone (p less than 0.001). Progesterone and cortisol concentrations measured in the blood samples draining the UTJ-isthmic region 6 h after ovulation did not significantly differ between the groups, but the C-group displayed significantly higher concentrations of progesterone in the UTJ-isthmic region compared with the levels measured in parallel samples taken of jugular blood (P less than 0.01). The C-group, but not the ACTH-group, also displayed a significant elevation in progesterone concentration 6 h after ovulation compared with the basal levels before ovulation (p less than 0.01). Numbers of retrieved spermatozoa were not significantly different between the C-group and the ACTH-group. However, there was a tendency for a larger number of spermatozoa among sows in the ACTH-group, especially in the isthmic segment adjacent to the AIJ. In conclusion, simulated stress induced by injections of ACTH during standing oestrus results in elevated concentrations of progesterone before ovulation and may interfere with the rise of progesterone after ovulation. However, ACTH-injections appeared to augment transport of spermatozoa through the female genital tract of pigs. (c) 2005 Elsevier B.V. All rights reserved.
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| 30. |
- Brandt, Y, et al.
(författare)
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Impact of ACTH during oestrus on the ultrastructure of the spermatozoa and their environment in the tubal reservoir of the postovulatory sow
- 2006
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Ingår i: Animal Reproduction Science. - : Elsevier Masson. - 0378-4320 .- 1873-2232. ; 93:3-4, s. 231-245
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Tidskriftsartikel (refereegranskat)abstract
- This study investigated whether injections of synthetic ACTH (simulating short-term stress) in sows during standing oestrus have a negative effect on spermatozoa and the local intraluminal environment in the utero-tubal junction (UTJ) and isthmus. Seven of the 14 sows were given ACTH through a jugular catheter every 2 h from the onset of standing oestrus until the sow ovulated (ACTH-group), while the other seven sows were given NaCl solution (C-group). All sows were artificially inseminated before ovulation. Six hours after ovulation (detected with transrectal ultrasonography) the sows were anaesthetised, the right oviduct was fixed in toto by vascular perfusion with glutaraldehyde, and the UTJ and specimens from the isthmus were prepared for scanning electron microscopy (SEM). SEM revealed that a seemingly viable population of spermatozoa remained in the UTJ 6 It after ovulation. A majority of sows in the ACTH-group had moderately to exaggerated amounts of mucus in the intraluminal environment of the sperm reservoir. In conclusion, stress simulated by exogenous ACTH in sows may alter the intraluminal environment of the sperm reservoir. (c) 2005 Elsevier B.V. All rights reserved.
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| 34. |
- Drouin, V., et al.
(författare)
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Deformation in the Northern Volcanic Zone of Iceland 2008-2014: An interplay of tectonic, magmatic, and glacial isostatic deformation
- 2017
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Ingår i: Journal of Geophysical Research-Solid Earth. - : American Geophysical Union (AGU). - 2169-9313 .- 2169-9356. ; 122:4, s. 3158-3178
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Tidskriftsartikel (refereegranskat)abstract
- GPS measurements spanning 2008 to 2014 are used to derive the surface velocity field across the Northern Volcanic Zone (NVZ) of Iceland, a subaerial part of the divergent boundary between the North American and Eurasian plates. No volcanic activity nor magmatic intrusions were detected in the zone during this time period. We infer an extensional rate of 17.4(-0.3)(+0.2) mm/yr in direction 292.0(-0.6)(+0.5 degrees),consistent with the results of previous studies and current plate motion models including MORVEL2010 and GEODVEL2010. The horizontal velocity field reveals about 50 km wide stretching zone caused by the divergent plate movements. Glacial isostatic adjustment (GIA) induces uplift of over 20 mm/yr at the northern edge of Vatnajokull ice cap and 3-4 mm/yr horizontal motion directed away from the ice cap. Deformation in the NVZ between 2008 and 2014 can be reproduced by a combination of models relating to several different processes: (i) Mogi sources for volcanic and geothermal deformation at the Askja and Krafla volcanoes, (ii) scaled version of a velocity field derived from a glacial isostatic model, and (iii) simple arctangent-based model for secular plate spreading. We find the approximate location of the plate boundary spreading axis as well as its locking depth. The spreading axis lies through the Krafla, Fremrinamar, and Askja central volcanoes, the most active ones in the NVZ. It does not appear to follow the general direction of each fissure swarm but rather to change direction at the central volcanoes. The locking depth is on average within the 7-9 km range.
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| 35. |
- Einarsson, Jonas, et al.
(författare)
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Periodic and aperiodic tumbling of microrods advected in a microchannel flow
- 2013
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Ingår i: Acta Mechanica. - : Springer Science and Business Media LLC. - 0001-5970 .- 1619-6937. ; 224:10, s. 2281-2289
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Tidskriftsartikel (refereegranskat)abstract
- We report on an experimental investigation of the tumbling of microrods in the shear flow of a microchannel (dimensions: 40 mm x 2.5 mm x 0.4 mm. The rods are 20-30 mu m long and their diameters are of the order of 1 mu m. Images of the centre-of-mass motion and the orientational dynamics of the rods are recorded using a microscope equipped with a CCD camera. A motorised microscope stage is used to track individual rods as they move along the channel. Automated image analysis determines the position and orientation of a tracked rod in each video frame. We find different behaviours, depending on the particle shape, its initial position, and orientation. First, we observe periodic as well as aperiodic tumbling. Second, the data show that different tumbling trajectories exhibit different sensitivities to external perturbations. These observations can be explained by slight asymmetries of the rods. Third, we observe that after some time, initially periodic trajectories lose their phase. We attribute this to drift of the centre of mass of the rod from one to another streamline of the channel flow.
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| 36. |
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| 37. |
- Einarsson, S., et al.
(författare)
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Automated determination of amino acid enantiomers using derivatization with 1 -(9-fluorenyl)ethyl chloroformateand reversed-phase liquid chromatography
- 2017
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Ingår i: High-Performance Liquid Chromatography of Peptides and Proteins: Separation, Analysis, and Conformation. - : CRC Press. ; , s. 369-378
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- The important role of chirality in nature has long been recognized. Large groups of biologically important molecules such as amino acids are chiral, and for understanding the properties of these substances it is necessary to separate and quantitate the enantiomers individually. The diverse vital function of amino acids in living organisms make it important to determine the ratios of the enantiomers in various areas, such as dating, 1 food chemistry, 2 and studies of extraterrestrial material. 3 For peptide synthesis, it is important to determine the enantiomeric purity of the amino acids used and the extent of racemization which may occur during the synthesis. For analytical procedures which involve liberation of the amino acids from peptides and proteins, it is necessary to check the extent of racemization in the hydrolysis procedure used. Studies have shown that the degree of racemization during hydrolysis varies from one type of peptide to another, and that peptide-bound amino acids generally racemize faster than free amino acids. © 1991 by CRC Press LLC.
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| 38. |
- Einarsson, S., et al.
(författare)
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Conference Lecture: Influence of stress on estrus, gametes and early embryo development in the sow
- 2008
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Ingår i: Theriogenology. - : Elsevier. - 0093-691X .- 1879-3231. ; 70:8, s. 1197-1201
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Tidskriftsartikel (refereegranskat)abstract
- Systems with loose-housed sows have become common. Regrouping, which is commonly done after weaning and may coincide with many important reproductive events, causes stressful situations with elevated blood cortisol concentrations. Depending on group size, approximately 2-7 d are required for a new group of sows to become relatively stable. In a series of studies, the social stress after regrouping was simulated with repeated adrenocorticortriphic hormone (ACTH) treatments for approximately 48 h. Sows were allocated into control and experimental groups, fitted with jugular catheters, and blood samples were collected every 2 or 4 h. Follicular development and ovulation were monitored by transrectal ultrasonography every 4 h. Simulated stress during proestrus prolonged estrus and disturbed the follicular growth and ovulation. Giving ACTH during estrus elevated concentrations of cortisol and progesterone, and chagned the intraluminal environment, including exaggerated amounts of mucus in the UTJ and isthmus. Although ACTH had no effect on the time of ovluation (relative to onset of standing estrus), or on embryo development, fewer oocytes/embryos were retrieved from the ACTH group than from the control group (51% vs. 81%, P less than 0.05), and there was a tendency towards faster embryo transportation to the uterus. Short-term fasting after ovulation had an unfavourable effect on sperm numbers in UTJ/isthmus, cleavage rate of fertlized ova, as well as ova transport through the isthmic part of the oviduct. Treatment with ACTH after ovulation redcued numbers of spermatozoa at the zona pellucida and retarded cleavage rate of fertilized ova. Therefore, the timing of stress seemed to be an important factor regarding effects on reproductive events. (C) 2008 Elsevier Inc. All rights reserved.
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| 39. |
- Einarsson, S., et al.
(författare)
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Short- and long-term effects of immunization against gonadotropin-releasing hormone, using Improvac (TM), on sexual maturity, reproductive organs and sperm morphology in male pigs
- 2009
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Ingår i: Theriogenology. - : Elsevier. - 0093-691X .- 1879-3231. ; 71:2, s. 302-310
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Tidskriftsartikel (refereegranskat)abstract
- The objective of this study was to determine the short and long term effects of a gonadotropin-releasing hormone (GnRH) vaccine (Improvac (TM) Pfizer Ltd.), on sexual maturity, development of the reproductive organs, and the morphology of caudal epididymal spermatozoa in non-castrated male pigs. The pigs were slaughtered 4, 16 or 22 weeks after the second Improvac (TM) vaccination. A total of 80 crossbred non-castrated male pigs were included in this study comprising two experiments, a short-effect (Experiment 1) and a long-effect (Experiment 2). The first experiment included 56 pigs, 24 of them were maintained as controls and 32 were vaccinated twice, and slaughtered 4 weeks after the second vaccination. The second experiment included 24 pigs, 12 controls and 12 vaccinated twice, and slaughtered either 16 weeks (n = 6) or 22 weeks (n = 6) after the second vaccination. None of the immunized pigs was sexually mature at slaughter, i.e. 4, 16 or 22 weeks after second vaccination. Corresponding results of the control pigs showed that 50% had reached sexual maturity at the age corresponding to 4 weeks after the second vaccination. and 100% at slaughter 16, respectively, 22 weeks after vaccination. At 4, 16 and 22 weeks after second vaccination both testes weight and bulbourethral length were significantly reduced (p less than 0.001). The percentages of proximal droplets and abnormal heads were significantly lower in the control pigs than in the immunized pigs at slaughter 4 weeks after vaccination, whereas distal droplets were higher. For the other morphological parameters no significant differences were seen, but all mean values except for acrosome defects were numerically lower in the control pigs compared with the immunized pigs. For pigs slaughtered 16 or 22 weeks after vaccination, the vaccination effect was significant for percentages of proximal droplets, distal droplets, acrosome defects, acrosome abnormality and abnormal heads (p = 0.017-0.001). The immunization clearly disrupted the number and morphology of the interstitial Leydig cells, lasting throughout the study period (4-22 weeks after vaccination). Spermatogenesis was also clearly affected in the immunized pigs, to various degrees, from mild disruption (spermatocyte loss, decrease of the normal number of layers of germ cells) to severe loss of germ cells including tubuli with Sertoli cells-only (complete disappearance of germ cells), also covering the entire study period. The results indicated that the effect of immunization persisted for at least 22 weeks after the second vaccination. (c) 2009 Elsevier Inc. All rights reserved.
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| 40. |
- Einarsson, U, et al.
(författare)
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Activities of daily living and social activities in people with multiple sclerosis in Stockholm County
- 2006
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Ingår i: Clinical rehabilitation. - : SAGE Publications. - 0269-2155 .- 1477-0873. ; 20:6, s. 543-551
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Tidskriftsartikel (refereegranskat)abstract
- Objective: To describe independence in personal and instrumental activities of daily living (ADL), and frequency of social/lifestyle activities in a population-based sample of people with multiple sclerosis in Stockholm. Design: Population-based survey. Setting: Data collection in home environment. Subjects: One hundred and sixty-six people with multiple sclerosis. Interventions: Data were collected using measurements and structured interviews. Main measures: Independence in ADL was assessed by the Barthel Index; independence in personal and instrumental ADL by the Katz Extended ADL Index; and frequency of social/lifestyle activities by the Frenchay Activities Index. Results: The mean age was 519 ± 12 years in the included 166 people with multiple sclerosis, of whom 71% ( n = 118) were women. Fifty-two per cent ( n = 85) were independent in personal ADL, 30% ( n = 50) in instrumental ADL, and 35% ( n = 57) had normal frequency of social/lifestyle activities. Most frequently affected ADL items were cleaning indoors and outdoors transportation (62%, n = 102) and the social/lifestyle items of household maintenance (59%, n = 97), walking outside (59%, n = 97), heavy housework (61%, n = 100), and gardening (68%, n = 112). Conclusions: ADL and social/lifestyle activities were affected in two-thirds of people with multiple sclerosis in Stockholm. The most affected items were items that could be classified as mobility-related and physically demanding, underlining the importance of developing and using evidence-based exercise treatments and rehabilitation to increase independence in people with multiple sclerosis in Stockholm.
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| 41. |
- Einarsson, U, et al.
(författare)
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Cognitive and motor function in people with multiple sclerosis in Stockholm County
- 2006
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Ingår i: Multiple sclerosis (Houndmills, Basingstoke, England). - : SAGE Publications. - 1352-4585 .- 1477-0970. ; 12:3, s. 340-353
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to analyse cognitive and motor function in a population-based sample of people with multiple sclerosis (PwMS), taking into account both disease-related data and sociodemographic factors. Data were collected from 166 PwMS during home visits. Cognitive function was assessed by the Mini-Mental State Examination (MMSE), the Free Recall and Recognition of 12 Random Words Test (FRR12RWT), and the Symbol Digit Modalities Test (SDMT); manual dexterity by the Nine-Hole Peg Test (NHPT); global motor capacity by the Lindmark Motor Capacity Assessment; and walking capacity by a timed 10-metre walk. On cognitive tests, 55% (MMSE), 84% (FRR12RWT), and 45% (SDMT) of PwMS scored within the normal range; 27% of PwMS displayed normal manual dexterity, 9% had a maximal motor-capacity score, and 8% walked at normal speed. Factors associated with normal cognitive function were lower disability and higher education; lower disability and current employment were predictive of capacity to perform the NHPT and to walk 10 metres. In conclusion, cognitive function was normal in approximately half of the PwMS investigated, while a minority displayed normal manual dexterity and normal walking capacity. Thus, both disease severity and socio-demographic factors appear to influence cognitive and motor function in MS.
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| 42. |
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| 43. |
- Einarsson, U, et al.
(författare)
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Multiple sclerosis in Stockholm County. A pilot study exploring the feasibility of assessment of impairment, disability and handicap by home visits
- 2003
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Ingår i: Clinical rehabilitation. - : SAGE Publications. - 0269-2155 .- 1477-0873. ; 17:3, s. 294-303
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Tidskriftsartikel (refereegranskat)abstract
- Objective: A pilot study performed within Stockholm County to evaluate the feasibility of collecting data using a comprehensive evaluation package administered in the home environment to assess impairment, disability and handicap in order to explore the consequences of multiple sclerosis (MS). Design: Home visits to 26 purposefully selected MS patients with different levels of disability, in both ordinary and sheltered living. The comprehensive evaluation package included: biographical data, Mini-Mental State Examination, Free Recall and Recognition of 12 Random Words Test, Symbol Digit Modalities Test, Beck Depression Index, Lindmark Motor Capacity Assessment, time to walk 10 metres, Nine-hole Peg Test, Barthel ADL Index, Katz Extended ADL Index, Frenchay Activities Index, Sickness Impact Profile and frequency of falls and injurious falls. Results: This pilot study demonstrates that the proposed methods can be used to evaluate MS patients differing in levels of disability and forms of living. The data collection method, based on home visits, was well accepted by the patients, their spouses and salaried personal assistants and could be performed within 2–21/2 hours. Conclusions: The evaluation package used in this pilot study is suitable for use in population-based studies and it should provide comprehensive information on the impact and consequences of MS on patients, and should contribute to the identification of areas in which the provision of rehabilitation and health care services needs to be improved.
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| 44. |
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| 45. |
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| 46. |
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| 47. |
- Ericzon, B G, et al.
(författare)
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Secretion and composition of bile after human liver transplantation : studies on the effects of cyclosporine and tacrolimus
- 1997
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Ingår i: Transplantation. - : Ovid Technologies (Wolters Kluwer Health). - 0041-1337 .- 1534-6080. ; 63:1, s. 74-80
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Tidskriftsartikel (refereegranskat)abstract
- Cyclosporine (CsA) and tacrolimus (FK506) have recently been reported to inhibit canalicular transport of bile acids in vitro and thereby possibly induce cholestasis. A relative reduction of chenodeoxycholic acid (CDCA) has been observed after liver transplantation when CsA is used as immunosuppressant. We tested the hypothesis that CsA induces cholestasis and reduces CDCA secretion as compared with treatment with monoclonal antibodies (OKT3), and that CsA differs from FK506 with regard to its effects on biliary lipid secretion.Bile flow, biliary lipid secretion rates, and biliary bile acid composition were determined during the first 10 days after transplantation in 29 liver transplant recipients. Two prospective randomized studies were performed that compared CsA and OKT3 and compared CsA- and FK506-based regimens. In study 1, bile acid output averaged 0.75±0.15 µmol/min in the CsA I group and 0.54±0.11 µmol/min in the OKT3 group on postoperative day 1. Bile flow and bile acid output then increased, and there was no significant difference between the two groups. The relative proportion of CDCA decreased to the same extent in both groups. In study 2, mean bile acid outputs on postoperative day 1 were 0.57±0.26 µmol/min and 0.55±0.15 µmol/min in the CsA 2 and FK506 groups, respectively. The following increase in bile acid secretion was significantly larger in the FK506 group. After transplantation, the relative proportion of CDCA decreased with time in both groups, but the reduction was more rapid in the FK506 group.In conclusion, CsA did not inhibit bile secretion during short-term treatment after liver transplantation. Compared with patients given CsA-based treatment, patients with FK506-based treatment recovered bile secretion more rapidly.
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| 48. |
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| 49. |
- Gomez, S., et al.
(författare)
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Differences between body movement adaptation to calf and neck muscle vibratory proprioceptive stimulation
- 2009
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Ingår i: Gait & Posture. - : Elsevier BV. - 1879-2219 .- 0966-6362. ; 30:1, s. 93-99
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Tidskriftsartikel (refereegranskat)abstract
- Adaptation is essential in maintaining stability during balance-challenging situations. We studied, ill standing subjects with eyes open and closed, adaptive responses of the anteroposterior head, shoulder, hip and knee movements: gastrocnemius and tibialis anterior EMG activity and anteroposterior body Posture when proprioceptive information from the neck or calf muscles underwent vibratory perturbations. After 30 s of quiet stance, vibratory stimuli were applied repeatedly for 200 s, and adaption to stimulation was analyzed in four successive 50 s periods. Repeated neck and calf vibration significantly increased linear body movement variance at all recorded sites (p < 0.001, except neck stimulation with eyes closed, EC-neck), increased tibialis anterior (p < 0.001, except EC-neck) and gastrocnemious muscle activity (p < 0.001). Most body movement variances and tibialis anterior EMG activity decreased significantly over time (most p-values < 0.01 or lower) and overall, the body leaning forward increased from 5.5 degrees to 6.5 degrees (p < 0.01). The characteristics of the responses were influenced by vision and site of vibration, e.g., neck vibration affected body Posture more rapidly than calf vibration. Our findings support the notion that proprioceptive perturbations have different effects in terms of nature, degree and adaptive response depending on site of vibratory proprioceptive stimulation, a factor that needs consideration in clinical investigations and design of rehabilitation programs. (C) 2009 Elsevier B.V. All rights reserved.
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| 50. |
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