| 61. |
- Franzen, Stephanie, et al.
(författare)
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Prevention of hemorrhage-induced renal vasoconstriction and hypoxia by angiotensin II type 1 receptor antagonism in pigs
- 2021
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Ingår i: American Journal of Physiology. Regulatory Integrative and Comparative Physiology. - : American Physiological Society. - 0363-6119 .- 1522-1490. ; 321:1, s. R12-R20
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Tidskriftsartikel (refereegranskat)abstract
- Angiotensin II (ANG II) is a potent vasoconstrictor and may reduce renal blood flow (RBF), causing renal hypoxia. Hypotensive hemorrhage elevates plasma ANG II levels and is associated with increased risk of acute kidney injury. We hypothesized that ANG II antagonism prevents renal vasoconstriction and hypoxia caused by hemorrhage. Pigs were anaesthetized, surgically prepared, and randomized to intravenous losartan (1.5 mg center dot kg-1 center dot h-1, n = 8) or an equal volume of intravenous Ringer acetate (vehicletreated, n = 8). Hemorrhage was induced by continuous aspiration of blood to reach and sustain mean arterial pressure of <50 mmHg for 30 min. Plasma ANG II levels, hemodynamics and oxygenation were assessed 60 min prehemorrhage, 30-min after the start of hemorrhage, and 60 min posthemorrhage. Erythropoietin mRNA was analyzed in cortical and medullary tissue sampled at the end of the experiment. Hypotensive hemorrhage increased plasma ANG II levels and decreased RBF and oxygen delivery in both groups. Losartan-treated animals recovered in RBF and oxygen delivery, whereas vehicle-treated animals had persistently reduced RBF and oxygen delivery. In accordance, renal vascular resistance increased over time post hemorrhage in vehicle-treated animals but was unchanged in losartan-treated animals. Renal oxygen extraction rate and cortical erythropoietin mRNA levels increased in the vehicle group but not in the losartan group. In conclusion, ANG II antagonism alleviates prolonged renal vasoconstriction and renal hypoxia in a large animal model of hypotensive hemorrhage.
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| 62. |
- Gibbons, Catherine, et al.
(författare)
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Postprandial profiles of CCK after high fat and high carbohydrate meals and the relationship to satiety in humans
- 2016
-
Ingår i: Peptides. - : Elsevier BV. - 0196-9781 .- 1873-5169. ; 77, s. 3-8
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Tidskriftsartikel (refereegranskat)abstract
- CONTEXT: CCK is understood to play a major role in appetite regulation. Difficulties in measuring CCK have limited the potential to assess its profile in relation to food-induced satiety. Improvements in methodology and progress in theoretical understanding of satiety/satiation make it timely for this to be revisited.OBJECTIVE: First, examine how physiologically relevant postprandial CCK8/33(s) profiles are influenced by fat (HF) or carbohydrate (HCHO) meals. Second, to examine relationships between postprandial CCK and profiles of satiety (hunger/fullness) and satiation (meal size).PARTICIPANTS AND DESIGN: Sixteen overweight/obese adults (11 females/5 males) participated in a randomised-crossover study (46 years, 29.8kg/m(2)) in a university research centre. Plasma was collected preprandially and for 180min postprandially. Simultaneously, ratings of hunger/fullness were tracked for 180min before an ad libitum lunch was provided.RESULTS: CCK8/33(s) levels increased more rapidly and reached a higher peak following HF compared to HCHO breakfast (F(1,15)=14.737, p<0.01). Profiles of hunger/fullness did not differ between conditions (F(1,15)=0.505, p=0.488; F(1,15)=2.277, p=0.152). There was no difference in energy intake from the ad libitum meal (HF-3958 versus HCHO-3925kJ; t(14)=0.201, p=0.844). CCK8/33(s) profiles were not associated with subjective appetite during early and late phases of satiety; nor was there an association between CCK8/33(s) and meal size.CONCLUSIONS: These results demonstrate CCK levels were higher after HF meal compared to HCHO isocaloric meal. There was no association between CCK levels and intensity of satiety, or with meal size. Under these circumstances, CCK does not appear to play a unique independent role in satiety/satiation. CCK probably acts in conjunction with other peptides and the action of the stomach.
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| 63. |
- Gibbons, Catherine, et al.
(författare)
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The Role of Episodic Postprandial Peptides in Exercise-Induced Compensatory Eating
- 2017
-
Ingår i: Journal of Clinical Endocrinology and Metabolism. - : The Endocrine Society. - 0021-972X .- 1945-7197. ; 102:11, s. 4051-4059
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Tidskriftsartikel (refereegranskat)abstract
- Context: Prolonged physical activity gives rise to variable degrees of body weight and fat loss, and is associated with variability in appetite control. Whether these effects are modulated by postprandial, peptides is unclear. We examined the role of postprandial peptide response in compensatory eating during 12 weeks of aerobic exercise and in response to high-fat, low-carbohydrate (HFLC) and low-fat, high-carbohydrate (LFHC) meals.Methods: Of the 32 overweight/obese individuals, 16 completed 12 weeks of aerobic exercise and 16 nonexercising control subjects were matched for age and body mass index. Exercisers were classified as responders or nonresponders depending on net energy balance from observed compared with expected body composition changes from measured energy expenditure. Plasma samples were collected before and after meals to compare profiles of total and acylated ghrelin, insulin, cholecystokinin, glucagon-like peptide 1 (GLP-1), and total peptide YY (PYY) between HFLC and LFHC meals, pre- and postexercise, and between groups.Results: No differences between pre- and postintervention peptide release. Responders had greater suppression of acylated ghrelin (P < 0.05) than nonresponders, as well as higher postprandial levels of GLP-1 (P < 0.001) and total PYY (P < 0.001) compared with nonresponders and control subjects.Conclusion: No impact on postprandial peptide release was found after 12 weeks of aerobic exercise. Responders to exercise-induced weight loss showed greater suppression of acylated ghrelin and greater release of GLP-1 and total PYY at baseline. Therefore, episodic postprandial peptide profiles appear to form part of the pre-existing physiology of exercise responders and suggest differences in satiety potential may underlie exercise-induced compensatory eating.
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| 64. |
- Hedberg, Jakob, 1972-
(författare)
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Gastrointestinal Physiology and Results following Bariatric Surgery
- 2010
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The number of operations for morbid obesity is rising fast. We have examined aspects of postoperative physiology and results after bariatric surgery. The pH in the proximal pouch after Roux-en-Y gastric bypass (RYGBP) was investigated with catheter-based and wire-less technique. Gastric emptying, PYY-levels in the fasting state and after a standardized meal was evaluated after biliopancreatic diversion with duodenal switch (DS). A clinical trial was undertaken, comparing DS to RYGBP in patients with BMI>48. Main outcome variables were safety and long-term weight results as well as abdominal symptoms and laboratory results. Patients with stomal ulcer had significantly lower pH in their proximal gastric pouch as compared to asymptomatic control subjects. Long-time pH measurements with the wire-less BRAVO-system were feasible and demonstrated pH<4 in median 10.5% of the time in asymptomatic post-RYGBP patients. After DS, the T50 of gastric emptying was 28±16 minutes. PYY-levels were higher after DS than in age-matched control subjects. BMI-reduction was greater after DS (24 BMI-units) than after RYGBP (17 BMI-units) in median 3.5 (2.0-5.3) years after surgery (p<0.001). Fasting glucose and HbA1c levels were lower one and three years after DS as compared to RYGBP. On the other hand, DS-patients reported having more diarrhea and malodorous flatus. This thesis has resulted in deepened knowledge. Acid produced in the proximal pouch is an important pathogenetic factor in the development of stomal ulcer after RYGBP. However, symptom-free patients have an acidic environment in the proximal Roux-limb as well. After DS, gastric emptying is fast, but not instantaneous, and PYY-levels are high. DS results in superior weight reduction and better glucose control as compared to RYGBP in patients with BMI>48. We believe that DS has a place in surgical treatment of the super-obese, even though symptoms of diarrhea and malodorous flatus are more common after DS.
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| 65. |
- Hedvall Kallerman, Pernilla, et al.
(författare)
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Levels of Persistent Halogenated Organic Pollutants (POP’s) in Mother’s Milk from First-Time Mothers in Uppsala, Sweden: Results from Year 2022, Chlorinated Pesticides from 2020-2022, and Temporal Trends for the Time Period 1996-2022
- 2024
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Sedan 1996 har Livsmedelsverket regelbundet samlat in modersmjölk från förstföderskor i Uppsala för analys av persistenta halogenerade organiska miljöföroreningar (POP). I följande rapport redovisas halterna av industrikemikalien PCB (mono-, di- och non-orto PCB), oavsiktligt bildade dioxiner och furaner (PCDD/F) och bromerade flamskyddsmedel (PBDE, HBCDD) i 15 modersmjölksprover insamlade 2022. De klorerade pesticiderna DDT (p,p’-DDT, p,p’-DDE, p,p’-DDD, o,p’-DDT), hexaklorbensen (HCB), hexaklorcyklohexan (β-HCH) och klordan (oxyklordan och transnonaklor) har analyserats i 3 pooler per år för åren 2020-2022. Nya data har också använts för att uppdatera tidstrenderna för dessa ämnen. Bland PCBerna var medelkoncentrationen i modersmjölk (2022) högst för CB 153 (18 ng/g fett). Medelhalten för PCDD TEQ och PCDF TEQ var för båda 1,0 pg/g fett beräknade med de nya toxiska ekvivaleringsfaktorerna, 2022 WHO TEF. Bland de polybromerade difenyletrarna (PBDE) hade BDE 153 (0,36 ng/g fett) högst medelhalt. Den DDT-förening som hade högst medelhalt i de poolade proverna var p,p’-DDE (28 ng/g fett).Utvärdering av tidstrender för perioden 1996-2022 visade att halterna av di-orto PCBer, mono-orto PCB TEQ och non-orto PCB TEQ har minskat med i medeltal 5-6 % per år. Halterna av PCDD TEQ har minskat fortare än halterna av PCDF TEQ (7 % respektive 2 % per år). När olika tidperioder studerades visade resultaten att minskningen skett snabbare i början av studien 1996-2006/2010 jämfört med den senare delen fram till 2022. För PCDF sågs ingen signifikant minskning 2008-2022. Även om modersmjölknivåerna av total TEQ minskar, hade fortfarande 4 av de 15 kvinnor som provtagits under 2022 nivåer över Efsas modellerade kritiska halt för modersmjölk (beräknat utifrån de tidigare TEFarna från 2005 eftersom Efsa ännu inte har uppdaterat sin riskvärdering med de nya TEFarna).En jämförelse mellan summahalter av dioxinlika PCB, PCDF och PCDD beräknade med 2005 WHO TEF och 2022 WHO TEF, gjordes för hela studien. Resultaten visade att summahalterna blir lägre med de nya TEFarna från 2022, i medel 38 % för summa PCB/PCDD/F TEQ.Halterna av BDE 47, BDE 99, BDE 100, och sumPBDE har minskat med 5-11% per år 1996-2022. När studieperioden delades upp i flera delar visar resultaten att halterna sjunker snabbare mot slutet av perioden. BDE 209 har bara analyserats kontinuerligt i modersmjölk sedan 2009 och för första gången ses en minskning av BDE 209 med i medeltal 5% per år. För BDE 153 och HBCDD ökade halterna signifikant i bröstmjölk 1996-2005/2007 och därefter minskade halterna med i medeltal 3 respektive 8 %.Halterna av klorpesticider i modersmjölk minskade med 5-10 % per år och för HCB sågs först en minskning för att sedan öka åren 2009-2016 och efter det minska. Resultaten stämmer överens med det som rapporterats tidigare inom POPUP. Fortsatta undersökningar av POPar i modersmjölk kan ge svar på om halterna av PCBer, PCDD/F och HCB håller på att stabiliseras på nuvarande nivåer eller om nivåerna fortsätter att minska.
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| 66. |
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| 67. |
- Holmin, Susanne, et al.
(författare)
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Corrosion of ruthenium dioxide based cathodes in alkaline medium caused by reverse currents
- 2014
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Ingår i: Electrochimica Acta. - : Elsevier BV. - 0013-4686 .- 1873-3859. ; 146:10, s. 30-36
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Tidskriftsartikel (refereegranskat)abstract
- A reverse current obtained during power shutdowns in industrial processes, such as chlor-alkali production or alkaline water electrolysis, is deleterious for hydrogen evolving ruthenium dioxide (Ru02) based cathodes. It has been observed that RuO2 coatings after a power shutdown, necessary for e.g. maintenance, are severely damaged unless polarization rectifiers are employed. In this work we show why these types of cathodes are sensitive to reverse currents, i.e. anodic currents, after hydrogen evolution. RuO2 coatings deposited on nickel substrates were subjected to different electrochemical treatments such as hydrogen evolution, oxygen evolution, or reverse currents in 8 M NaOH at 90 degrees C. Polarity inversion was introduced after hydrogen evolution to simulate the effect of reverse currents. Because of chemical interaction with hydrogen, a significant amount of the RuO2 coating was transformed into hydroxylated species during cathodic polarization. Our study shows that these hydroxylated phases are highly sensitive to electrochemical corrosion during anodic polarization after extended hydrogen evolution. (C) 2014 Elsevier Ltd. All rights reserved.
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| 68. |
- Kjellström, Erik, et al.
(författare)
-
Simulated climate conditions in Europe during the Marine Isotope Stage 3 stadial
- 2010
-
Ingår i: Boreas. - : Wiley. - 0300-9483 .- 1502-3885. ; 39:2, s. 436-456
-
Tidskriftsartikel (refereegranskat)abstract
- State-of-the-art climate models were used to simulate climate conditions in Europe during Greenland Stadial (GS) 12 at 44 ka BP. The models employed for these simulations were: (i) a fully coupled atmosphere-ocean global climate model (AOGCM), and (ii) a regional atmospheric climate model (RCM) to dynamically downscale results from the global model for a more detailed investigation of European climate conditions. The vegetation was simulated off-line by a dynamic vegetation model forced by the climate from the RCM. The resulting vegetation was then compared with the a priori vegetation used in the first simulation. In a subsequent step, the RCM was rerun to yield a new climate more consistent with the simulated vegetation. Forcing conditions included orbital forcing, land-sea distribution, ice-sheet configuration, and atmospheric greenhouse gas concentrations representative for 44 ka BP. The results show a cold climate on the global scale, with global annual mean surface temperatures 5 degrees C colder than the modern climate. This is still significantly warmer than temperatures derived from the same model system for the Last Glacial Maximum (LGM). Regional, northern European climate is much colder than today, but still significantly warmer than during the LGM. Comparisons between the simulated climate and proxy-based sea-surface temperature reconstructions show that the results are in broad agreement, albeit with a possible cold bias in parts of the North Atlantic in summer. Given a prescribed restricted Marine Isotope Stage 3 ice-sheet configuration, with large ice-free regions in Sweden and Finland, the AOGCM and RCM model simulations produce a cold and dry climate in line with the restricted ice-sheet configuration during GS 12. The simulated temperature climate, with prescribed ice-free conditions in south-central Fennoscandia, is favourable for the development of permafrost, but does not allow local ice-sheet formation as all snow melts during summer.
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| 69. |
- Kjellström, Erik, et al.
(författare)
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Simulated climate conditions in Fennoscandia during a MIS 3 stadial
- 2010
-
Ingår i: Boreas. - : Wiley. - 0300-9483 .- 1502-3885. ; 39:2, s. 436-456
-
Tidskriftsartikel (refereegranskat)abstract
- State-of-the-art climate models were used to simulate climate conditions in Europe during Greenland Stadial (GS) 12 at 44 ka BP. The models employed for these simulations were: (i) a fully coupled atmosphere–ocean global climate model (AOGCM), and (ii) a regional atmospheric climate model (RCM) to dynamically downscale results from the global model for a more detailed investigation of European climate conditions. The vegetation was simulated off-line by a dynamic vegetation model forced by the climate from the RCM. The resulting vegetation was then compared with the a priori vegetation used in the first simulation. In a subsequent step, the RCM was rerun to yield a new climate more consistent with the simulated vegetation. Forcing conditions included orbital forcing, land–sea distribution, ice-sheet configuration, and atmospheric greenhouse gas concentrations representative for 44 ka BP. The results show a cold climate on the global scale, with global annual mean surface temperatures 5 °C colder than the modern climate. This is still significantly warmer than temperatures derived from the same model system for the Last Glacial Maximum (LGM). Regional, northern European climate is much colder than today, but still significantly warmer than during the LGM. Comparisons between the simulated climate and proxy-based sea-surface temperature reconstructions show that the results are in broad agreement, albeit with a possible cold bias in parts of the North Atlantic in summer. Given a prescribed restricted Marine Isotope Stage 3 ice-sheet configuration, with large ice-free regions in Sweden and Finland, the AOGCM and RCM model simulations produce a cold and dry climate in line with the restricted ice-sheet configuration during GS 12. The simulated temperature climate, with prescribed ice-free conditions in south-central Fennoscandia, is favourable for the development of permafrost, but does not allow local ice-sheet formation as all snow melts during summer.
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| 70. |
- Lindblom, Ove, et al.
(författare)
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A study of bending waves in infinite and anisotropic plates
- 1997
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Ingår i: Applications of Mathematics. - 0862-7940 .- 1572-9109. ; 42:3, s. 213-232
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Tidskriftsartikel (refereegranskat)abstract
- In this paper we present a unified approach to obtain integral representation formulas for describing the propagation of bending waves in infinite plates. The general anisotropic case is included and both new and well-known formulas are obtained in special cases (e.g. the classical Boussinesq formula). The formulas we have derived have been compared with experimental data and the coincidence is very good in all cases
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