| 1. |
- Klionsky, Daniel J., et al.
(författare)
-
Guidelines for the use and interpretation of assays for monitoring autophagy in higher eukaryotes
- 2008
-
Ingår i: Autophagy. - : Landes Bioscience. - 1554-8627 .- 1554-8635. ; 4:2, s. 151-175
-
Forskningsöversikt (refereegranskat)abstract
- Research in autophagy continues to accelerate,1 and as a result many new scientists are entering the field. Accordingly, it is important to establish a standard set of criteria for monitoring macroautophagy in different organisms. Recent reviews have described the range of assays that have been used for this purpose.2,3 There are many useful and convenient methods that can be used to monitor macroautophagy in yeast, but relatively few in other model systems, and there is much confusion regarding acceptable methods to measure macroautophagy in higher eukaryotes. A key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers of autophagosomes versus those that measure flux through the autophagy pathway; thus, a block in macroautophagy that results in autophagosome accumulation needs to be differentiated from fully functional autophagy that includes delivery to, and degradation within, lysosomes (in most higher eukaryotes) or the vacuole (in plants and fungi). Here, we present a set of guidelines for the selection and interpretation of the methods that can be used by investigators who are attempting to examine macroautophagy and related processes, as well as by reviewers who need to provide realistic and reasonable critiques of papers that investigate these processes. This set of guidelines is not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to verify an autophagic response.
|
|
| 2. |
- Graslund, S, et al.
(författare)
-
Protein production and purification
- 2008
-
Ingår i: Nature methods. - : Springer Science and Business Media LLC. - 1548-7105 .- 1548-7091. ; 5:2, s. 135-146
-
Tidskriftsartikel (refereegranskat)
|
|
| 3. |
|
|
| 4. |
- Klug, Stefanie J, et al.
(författare)
-
TP53 codon 72 polymorphism and cervical cancer : a pooled analysis of individual data from 49 studies
- 2009
-
Ingår i: The Lancet Oncology. - 1470-2045 .- 1474-5488. ; 10:8, s. 772-784
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Cervical cancer is caused primarily by human papillomaviruses (HPV). The polymorphism rs1042522 at codon 72 of the TP53 tumour-suppressor gene has been investigated as a genetic cofactor. More than 80 studies were done between 1998 and 2006, after it was initially reported that women who are homozygous for the arginine allele had a risk for cervical cancer seven times higher than women who were heterozygous for the allele. However, results have been inconsistent. Here we analyse pooled data from 49 studies to determine whether there is an association between TP53 codon 72 polymorphism and cervical cancer. METHODS: Individual data on 7946 cases and 7888 controls from 49 different studies worldwide were reanalysed. Odds ratios (OR) were estimated using logistic regression, stratifying by study and ethnic origin. Subgroup analyses were done for infection with HPV, ethnic origin, Hardy-Weinberg equilibrium, study quality, and the material used to determine TP53 genotype. FINDINGS: The pooled estimates (OR) for invasive cervical cancer were 1.22 (95% CI 1.08-1.39) for arginine homozygotes compared with heterozygotes, and 1.13 (0.94-1.35) for arginine homozygotes versus proline homozygotes. Subgroup analyses showed significant excess risks only in studies where controls were not in Hardy-Weinberg equilibrium (1.71 [1.21-2.42] for arginine homozygotes compared with heterozygotes), in non-epidemiological studies (1.35 [1.15-1.58] for arginine homozygotes compared with heterozygotes), and in studies where TP53 genotype was determined from tumour tissue (1.39 [1.13-1.73] for arginine homozygotes compared with heterozygotes). Null results were noted in studies with sound epidemiological design and conduct (1.06 [0.87-1.29] for arginine homozygotes compared with heterozygotes), and studies in which TP53 genotype was determined from white blood cells (1.06 [0.87-1.29] for arginine homozygotes compared with heterozygotes). INTERPRETATION: Subgroup analyses indicated that excess risks were most likely not due to clinical or biological factors, but to errors in study methods. No association was found between cervical cancer and TP53 codon 72 polymorphism when the analysis was restricted to methodologically sound studies.
|
|
| 5. |
- Lynch, S.A., et al.
(författare)
-
Toward silicon-based lasers for terahertz sources
- 2006
-
Ingår i: IEEE Journal of Selected Topics in Quantum Electronics. - 1077-260X .- 1558-4542. ; 12:6, s. 1570-1577
-
Tidskriftsartikel (refereegranskat)abstract
- Producing an electrically pumped silicon-based laser at terahertz frequencies is gaining increased attention these days. This paper reviews the recent advances in the search for a silicon-based terahertz laser. Topics covered include resonant tunneling in p-type Si/SiGe, terahertz intersubband electroluminescence from quantum cascade structures, intersubband lifetime measurements in Si/SiGe quantum wells, enhanced optical guiding using buried suicide layers, and the potential for exploiting common impurity dopants in silicon such as boron and phosphorus to realize a terahertz laser. © 2006 IEEE.
|
|
| 6. |
|
|
| 7. |
- Harrington, Robert A., et al.
(författare)
-
The Thrombin Receptor Antagonist for Clinical Event Reduction in Acute Coronary Syndrome (TRA.CER) trial : study design and rationale
- 2009
-
Ingår i: American Heart Journal. - : Elsevier BV. - 0002-8703 .- 1097-6744. ; 158:3, s. 327-334
-
Tidskriftsartikel (refereegranskat)abstract
- Background The protease-activated receptor 1 (PAR-1), the main platelet receptor for thrombin, represents a novel target for treatment of arterial thrombosis, and SCH 530348 is an orally active, selective, competitive PAR-1 antagonist. We designed TRA.CER to evaluate the efficacy and safety of SCH 530348 compared with placebo in addition to standard of care in patients with non-ST-segment elevation (NSTE) acute coronary syndromes (ACS) and high-risk features. Trial design TRA.CER is a prospective, randomized, double-blind, multicenter, phase III trial with an original estimated sample size of 10,000 subjects. Our primary objective is to demonstrate that SCH 530348 in addition to standard of care will reduce the incidence of the composite of cardiovascular death, myocardial infarction (MI), stroke, recurrent ischemia with rehospitalization, and urgent coronary revascularization compared with standard of care alone. Our key secondary objective is to determine whether SCH 530348 will reduce the composite of cardiovascular death, MI, or stroke compared with standard of care alone. Secondary objectives related to safety are the composite of moderate and severe GUSTO bleeding and clinically significant TIMI bleeding. The trial will continue until a predetermined minimum number of centrally adjudicated primary and key secondary end point events have occurred and all subjects have participated in the study for at least I year. The TRA.CER trial is part of the large phase III SCH 530348 development program that includes a concomitant evaluation in secondary prevention. Conclusion TRA.CER will define efficacy and safety of the novel platelet PAR-1 inhibitor SCH 530348 in the treatment of high-risk patients with NSTE ACS in the setting of current treatment strategies.
|
|
| 8. |
- Kirkland, Thomas A., et al.
(författare)
-
Synthesis of glutamic acid analogs as potent inhibitors of leukotriene A(4) hydrolase
- 2008
-
Ingår i: Bioorganic & Medicinal Chemistry. - : Elsevier BV. - 0968-0896 .- 1464-3391. ; 16:9, s. 4963-4983
-
Tidskriftsartikel (refereegranskat)abstract
- Leukotriene B-4 (LTB4) is a potent pro-inflammatory mediator that has been implicated in the pathogenesis of multiple diseases, including psoriasis, inflammatory bowel disease, multiple sclerosis and asthma. As a method to decrease the level of LTB4 and possibly identify novel treatments, inhibitors of the LTB4 biosynthetic enzyme, leukotriene A(4) hydrolase (LTA(4)-h), have been explored. Here we describe the discovery of a potent inhibitor of LTA(4)-h, arylamide of glutamic acid 4f, starting from the corresponding glycinamide 2. Analogs of 4f are then described, focusing on compounds that are both active and stable in whole blood. This effort culminated in the identification of amino alcohol 12a and amino ester 6b which meet these criteria.
|
|
| 9. |
- Lai, I. H, et al.
(författare)
-
A unique tetrameric structure of deer plasma haptoglobin – an evolutionary advantage in the Hp 2-2 phenotype with homogeneous structure
- 2008
-
Ingår i: FEBS Journal. - 1742-4658 .- 1742-464X. ; 275, s. 981-993
-
Tidskriftsartikel (refereegranskat)abstract
- Similar to blood types, human plasma haptoglobin (Hp) is classified intothree phenotypes: Hp 1-1, 2-1 and 2-2. They are genetically inheritedfrom two alleles Hp 1 and Hp 2 (represented in bold), but only theHp 1-1 phenotype is found in almost all animal species. The Hp 2-2protein consists of complicated large polymers cross-linked by a2-bsubunits or (a2-b)n (where n ‡ 3, up to 12 or more), and is associatedwith the risk of the development of diabetic, cardiovascular and inflammatorydiseases. In the present study, we found that deer plasma Hpmimics human Hp 2, containing a tandem repeat over the a-chain basedon our cloned cDNA sequence. Interestingly, the isolated deer Hp ishomogeneous and tetrameric, i.e. (a-b)4, although the locations of )SHgroups (responsible for the formation of polymers) are exactly identicalto that of human. Denaturation of deer Hp using 6 m urea under reducingconditions (143 mm b-mercaptoethanol), followed by renaturation,sustained the formation of (a-b)4, suggesting that the Hp tetramers arenot randomly assembled. Interestingly, an a-chain monoclonal antibody(W1), known to recognize both human and deer a-chains, only binds tointact human Hp polymers, but not to deer Hp tetramers. This impliesthat the epitope of the deer a-chain is no longer exposed on the surfacewhen Hp tetramers are formed. We propose that steric hindrance playsa major role in determining the polymeric formation in human and deerpolymers. Phylogenetic and immunochemical analyses revealed that theHp 2 allele of deer might have arisen at least 25 million years ago. Amechanism involved in forming Hp tetramers is proposed and discussed,and the possibility is raised that the evolved tetrameric structure of deerHp might confer a physiological advantage.
|
|
| 10. |
|
|
| 11. |
- Zhao, Ming, et al.
(författare)
-
Strain-symmetrized Si/SiGe multi-quantum well structures grown by molecular beam epitaxy for intersubband engineering
- 2006
-
Ingår i: Journal of luminescence. - : Elsevier BV. - 0022-2313. ; 121:2, s. 403-408
-
Tidskriftsartikel (refereegranskat)abstract
- Three strain-symmetrized Si/SiGe multi-quantum well structures, designed for probing the carrier lifetime of intrawell intersubband transitions between heavy hole 1 (HH1) and light hole 1 (LH1) states with transition energies below the optical phonon energy, were grown by molecular beam epitaxy at low temperature on fully relaxed SiGe virtual substrates. The grown structures were characterized by using various experimental techniques, showing a high crystalline quality and very precise growth control. The lifetime of the LH1 excited state was determined directly with pump-probe spectroscopy. The measurements indicated an increase of the lifetime by a factor of 2 due to the increasingly unconfined LH1 state, which agreed very well with the design. It also showed a very long lifetime of several hundred picoseconds for the holes excited out of the well to transit back to the well through a diagonal process.
|
|
| 12. |
- Andersson, Irene, 1978, et al.
(författare)
-
Increased atherosclerotic lesion area in apoE deficient mice overexpressing bovine growth hormone
- 2006
-
Ingår i: Atherosclerosis. - : Elsevier BV. - 0021-9150. ; 188:2, s. 331-40
-
Tidskriftsartikel (refereegranskat)abstract
- Human growth hormone (GH) excess is linked to increased cardiovascular morbidity and mortality. However, little is known about the effect of GH excess on atherosclerosis. We developed a new mouse model to assess the hypothesis that GH overexpression accelerates atherosclerotic lesion formation. apoE(-/-) mice were crossed with bovine GH (bGH) transgenic mice to yield apoE(-/-) mice overexpressing bGH (apoE(-/-)/bGH). The mice were fed either standard or Western diet. At 22 weeks, atherosclerotic lesion area of thoracic aorta was larger in apoE(-/-)/bGH mice compared with littermate apoE(-/-) mice fed either diet (standard: +161+/-50%, Western: +430+/-134%). Aortic sinus lesions were more severe in apoE(-/-)/bGH mice fed standard diet compared with littermate apoE(-/-) mice. apoE(-/-)/bGH mice had lower (VLDL+LDL)/HDL ratios compared with littermate apoE(-/-) mice, while systolic blood pressure was higher in apoE(-/-)/bGH mice, irrespective of diet. The levels of serum amyloid A and hepatic CRP mRNA were higher in apoE(-/-)/bGH mice than in littermate apoE(-/-) mice. In conclusion, this study shows that excess GH augments the development of atherosclerosis in apoE(-/-) mice. The mechanisms could be direct effects of GH on cellular processes in the vessel wall or the result of concomitant processes such as hypertension or a general inflammatory state.
|
|
| 13. |
- Bernberg, Evelina, 1981, et al.
(författare)
-
Effects of social isolation and environmental enrichment on atherosclerosis in ApoE-/- mice
- 2008
-
Ingår i: Stress. - 1607-8888 .- 1025-3890. ; 11:5, s. 381-9
-
Tidskriftsartikel (refereegranskat)abstract
- Social support and a stimulating environment have been suggested to reduce stress reactions and cardiovascular risk. The aim of this study was to assess the role of environmental enrichment and social interaction for development of atherosclerosis in atherosclerosis prone mice. Male ApoE-/- mice were divided into four groups and followed during 20 weeks: (i) enriched environment (E, n=12), (ii) deprived environment (ED, n=12), (iii) enriched environment with exercise (E-Ex, n=12) and (iv) socially deprived by individual housing (SD, n=10). Plasma lipid and cytokine concentrations were measured. Atherosclerosis was quantified in cross-sections of innominate artery and en face in thoracic aorta. Plaque area was significantly increased in SD mice in the innominate artery (P<0.05 vs. all other groups), but not in the thoracic aorta. Plasma lipids were increased in SD mice (P<0.001 vs. all for total cholesterol, P<0.05 vs. E and P<0.01 vs. ED for triglycerides). Plasma concentration of granulocyte-colony stimulating factor (G-CSF) was decreased in SD mice compared to E mice (P<0.05). Thus, social isolation increased atherosclerosis and plasma lipids in ApoE-/- mice. Reduction in plasma G-CSF levels may hamper endothelial regeneration in the atherosclerotic process. While environmental enrichment did not affect atherosclerosis, social isolation accelerated atherosclerosis.
|
|
| 14. |
- Chai, Chun-Ming, et al.
(författare)
-
Incidence of Ventricular Fibrillation during Left Coronary Arteriography in Pigs: Comparison of a Solution of the Nonionic Dimer Iodixanol with Solutions of Five Different Nonionic Monomers
- 2008
-
Ingår i: Acta Radiologica. - : SAGE Publications. - 0284-1851 .- 1600-0455. ; 49:2, s. 150-156
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Solutions of iodine contrast media (CM) used for selective coronary arteriography (CA) should have minimal propensity to cause ventricular fibrillation (VF). Commonly used CM for CA are nonionic monomers or dimers. Purpose: To compare VF propensity of ready-to-use solutions of one nonionic dimer, iodixanol, and five nonionic monomers, iobitridol, iopamidol, iomeprol, iopromide, and ioversol. Material and Methods: Twenty milliliters of each CM was injected into the left coronary artery (LCA) through an inflated balloon catheter (0.5 ml/s) in 14 pigs; the longest period of injection was 40 s. If VF occurred before 40 s, the injection was stopped and the heart was defibrillated. After VF, there was a delay of 40 min before the next injection. Hemodynamic parameters and vector electrocardiography (VECG) were monitored. A CM with a lower frequency of VF and a longer period between start of injection and start of VF was considered to have a lower VF propensity. Results: Following 14 injections, each of the five nonionic monomers caused 14 VF, whereas iodixanol caused three VF (P<0.01). When VF occurred after iodixanol, it occurred later than after the other CM (P<0.001). Iodixanol caused less prolongation in QRS time (P<0.01) and QTc time (P<0.05) than the other CM. Prolongations in QRS and QTc times caused by CM parallel the VF propensities of the CM. Conclusion: Ready-to-use solutions of the dimer iodixanol have lower VF propensity than solutions of the five monomeric CM. This is related to the fact that the solutions of the dimer iodixanol have lower osmolality, higher viscosity, and higher concentrations of NaCl and CaCl2 than solutions of the five monomers.
|
|
| 15. |
- Elmståhl, Barbara, et al.
(författare)
-
Histomorphological Changes after Renal X-Ray Arteriography Using Iodine and Gadolinium Contrast Media in an Ischemic Porcine Model.
- 2007
-
Ingår i: Acta Radiologica. - : SAGE Publications. - 1600-0455 .- 0284-1851. ; 48:10, s. 1109-1119
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Gadolinium contrast media (Gd-CM) are regarded as non-nephrotoxic or considerably less nephrotoxic than iodine contrast media (I-CM), and have therefore come to be used as a substitute for I-CM in patients with renal insufficiency in a variety of radiographic examinations. Purpose: To investigate renal histomorphological changes caused by Gd-CM in comparison with I-CM after renal X-ray arteriography in an ischemic porcine model, and to evaluate these changes in relation to the nephrotoxicity of the CM used. Material and Methods: Test solutions: gadopentetate, gadodiamide, iohexol, gadobutrol, iopromide, iodixanol, mannitol, and saline. The experiments were performed on 152 animals. Each pig was randomized to receive one test solution injected into the balloon-occluded (10 min) right renal artery. The kidneys were evaluated histomorphologically. The severity of histomorphological changes was graded subjectively: 1 = minimal, 2 = mild, 3 = moderate, and 4 = marked. Results: The main histological changes were 1) proximal tubular and glomerular necrosis, 2) hemorrhage/congestion of the cortex, medulla, and glomeruli, 3) proximal tubular vacuolation, and 4) protein-filled tubules in the cortex and medulla. Necrosis and hemorrhage/congestion were more frequent after injections with gadopentetate, mannitol solution iso-osmotic to gadopentetate, and gadobutrol compared to all other groups (P<0.001). The degree of necrosis and hemorrhage/congestion was related to the degree of impairment of renal function, but inversely related to vacuolation and tubular protein filling. Conclusion: In ischemic porcine kidneys, the histomorphological changes caused by Gd-CM are similar to those caused by I-CM. Vacuolation appears to be independent of the osmolality and viscosity of the CM, and does not seem to be an indicator of renal impairment. “High-osmolal” Gd-CM are more nephrotoxic than “low- and iso-osmolal” I-CM when compared in equal volumes of concentrations, resulting in equal X-ray attenuation.
|
|
| 16. |
- Golman, Klaes, et al.
(författare)
-
Cardiac metabolism measured noninvasively by hyperpolarized (13)C MRI.
- 2008
-
Ingår i: Magnetic Resonance in Medicine. - : Wiley. - 1522-2594 .- 0740-3194. ; 59:5, s. 1005-1013
-
Tidskriftsartikel (refereegranskat)abstract
- Pyruvate is included in the energy production of the heart muscle and is metabolized into lactate, alanine, and CO(2) in equilibrium with HCO(3) (-). The aim of this study was to evaluate the feasibility of using (13)C hyperpolarization enhanced MRI to monitor pyruvate metabolism in the heart during an ischemic episode. The left circumflex artery of pigs (4 months, male, 29-34 kg) was occluded for 15 or 45 min followed by 2 hr of reperfusion. Pigs were examined by (13)C chemical shift imaging following intravenous injection of 1-(13)C pyruvate. (13)C chemical shift MR imaging was used in order to visualize the local concentrations of the metabolites. After a 15-min occlusion (no infarct) the bicarbonate signal level in the affected area was reduced (25-44%) compared with the normal myocardium. Alanine signal level was normal. After a 45-min occlusion (infarction) the bicarbonate signal was almost absent (0.2-11%) and the alanine signal was reduced (27-51%). Due to image-folding artifacts the data obtained for lactate were inconclusive. These studies demonstrate that cardiac metabolic imaging with hyperpolarized 1-(13)C-pyruvate is feasible. The changes in concentrations of the metabolites within a minute after injection can be detected and metabolic maps constructed. Magn Reson Med 59:1005-1013, 2008. (c) 2008 Wiley-Liss, Inc.
|
|
| 17. |
- Grönros, Julia, 1978, et al.
(författare)
-
Effects of rosuvastatin on cardiovascular morphology and function in an ApoE-knockout mouse model of atherosclerosis
- 2008
-
Ingår i: American Journal of Physiology-Heart and Circulatory Physiology. - : American Physiological Society. - 0363-6135 .- 1522-1539. ; 295:5
-
Tidskriftsartikel (refereegranskat)abstract
- This study investigated the effects of rosuvastatin on plaque progression and in vivo coronary artery function in apolipoprotein E-knockout (ApoE-KO) mice, using noninvasive high-resolution ultrasound techniques. Eight-week-old male ApoE-KO mice ( n = 20) were fed a high-fat diet with or without rosuvastatin (10 μmol·kg−1·day−1) for 16 wk. When compared with control, rosuvastatin reduced total cholesterol levels ( P < 0.05) and caused significant retardation of lesion progression in the brachiocephalic artery, as visualized in vivo using an ultrasound biomicroscope ( P < 0.05). Histological analysis confirmed the reduction of brachiocephalic atherosclerosis and also revealed an increase in collagen content in the statin-treated group ( P < 0.05). Coronary volumetric flow was measured by simultaneous recording of Doppler velocity signals and left coronary artery morphology before and during adenosine infusion. The hyperemic flow in response to adenosine was significantly greater in left coronary artery following 16 wk of rosuvastatin treatment ( P < 0.001), whereas the baseline flow was similar in both groups. In conclusion, rosuvastatin reduced brachiocephalic artery atherosclerotic plaques in ApoE-KO mice. Coronary artery function assessed using recently developed in vivo ultrasound-based protocols, also improved.
|
|
| 18. |
- Haugen, Espen, 1973, et al.
(författare)
-
Parallel gene expressions of IL-6 and BNP during cardiac hypertrophy complicated with diastolic dysfunction in spontaneously hypertensive rats.
- 2007
-
Ingår i: International journal of cardiology. - : Elsevier BV. - 1874-1754 .- 0167-5273. ; 115:1, s. 24-8
-
Tidskriftsartikel (refereegranskat)abstract
- There is increasing evidence showing that inflammation is involved in heart failure. However, heart failure may differ greatly due to different aetiologies. The role of inflammation in hypertensive heart failure, particularly in the early stage of cardiac dysfunction, has not been studied completely. This study aims at finding out whether inflammation is involved in the early stage of heart dysfunction due to hypertension. METHODS: Ten spontaneously hypertensive rats (SHR) and ten age-matched Wistar rats were used. Cardiac morphology and function, as well as coronary flow reserve, were examined by echocardiography. mRNAs for cytokines and brain natriuretic peptide were determined by RT-PCR. RESULTS: The results demonstrate cardiac hypertrophy with increased heart/body weight ratio in SHR. Echocardiographic examination has shown that SHR developed diastolic heart dysfunction as determined by tissue Doppler without decrease in systolic function. In heart biopsies, there were increased mRNA levels for interleukin-6 and brain natriuretic peptide whereas decreased mRNA for interleukin-2, beta adrenergic receptor, interferon and NFkb in SHR as compared to WKY group. Coronary flow remained unchanged in both groups. CONCLUSION: SHR developed cardiac hypertrophy complicated with diastolic heart dysfunction with increased expression of brain natriuretic peptide, down-regulation of beta adrenergic receptors and simultaneous up-regulation of IL-6, which indicates active proinflammatory process as, at least partly, underlying mechanism during the early stage when cardiac hypertrophy associated with diastolic dysfunction occurs.
|
|
| 19. |
- Jiao, Liping, et al.
(författare)
-
Persistent toxic substances in remote lake and coastal sediments from Svalbard, Norwegian Arctic : Levels, sources and fluxes
- 2009
-
Ingår i: Environmental Pollution. - : Elsevier. - 0269-7491 .- 1873-6424. ; 157:4, s. 1342-1351
-
Tidskriftsartikel (refereegranskat)abstract
- Surface sediments from remote lakes and coastal areas from Ny-Ålesund, Svalbard, Norwegian Arctic were analyzed for polycyclic aromatic hydrocarbons (PAHs), polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs). Relatively high levels of PAHs were encountered from several lakes from Ny-Ålesund, which were within the range of levels reported for European high mountain lakes and some urban/industrialized areas in the world, pointing to the role of remote Arctic lakes as potential reservoir of semi-volatile organic compounds. Specific patterns of PBDEs were observed, showing higher concentrations of lower brominated compounds such as BDE-7, 17 and 28. Estimated surface sediment fluxes of PAHs in Ny-Ålesund remote lakes were similar to those observed for some European high mountain lakes. The current PAH levels in sediments from three lakes exceeded Canadian sediment quality guidelines, suggesting the presence of possible risks for aquatic organisms and the need for further studies.
|
|
| 20. |
- Johansson, Maria E, 1977, et al.
(författare)
-
High-salt diet combined with elevated angiotensin II accelerates atherosclerosis in apolipoprotein E-deficient mice.
- 2009
-
Ingår i: Journal of hypertension. - 0263-6352 .- 0263-6352. ; 27:1, s. 41-7
-
Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: High-salt diet likely elevates blood pressure (BP), thus increasing the risk of cardiovascular events. We hypothesized that a high-salt diet plays a critical role in subjects whose renin-angiotensin systems cannot adjust to variable salt intake, rendering them more susceptible to atherosclerosis. METHODS: Apolipoprotein E-deficient (ApoE-/-) mice received standard or high-salt diet (8%) alone or in combination with fixed angiotensin II (Ang II) infusion (0.5 microg/kg per min). BP was measured using telemetry, and plaque burden was assessed in the thoracic aorta and innominate artery. We used urinary isoprostane as a marker for oxidative stress. RESULTS: Although high-salt diet per se did not affect plaque extension, high salt combined with Ang II increased plaque area significantly in both the aorta and the innominate artery as compared with Ang II or salt alone (P < 0.05 and P < 0.01, respectively). High-salt diet did not affect BP or isoprostane levels, whereas Ang II infusion increased both BP and isoprostane levels (P < 0.05 and P < 0.01, respectively). Although high-salt diet combined with Ang II did not amplify BP, salt in combination with Ang II increased isoprostane levels further (P < 0.001 vs. Ang II alone). Ang II increases macrophage content in lesions (P < 0.05), whereas salt likely increases collagen content. CONCLUSION: High-salt diet per se does not influence BP in ApoE-/- mice and is only moderately atherogenic. Possibly mediated via increased oxidative stress, a high-salt diet combined with fixed high Ang II levels accelerates atherogenesis synergistically, beyond the effect of BP.
|
|
| 21. |
- Magnusson, Peter, et al.
(författare)
-
Passive catheter tracking during interventional MRI using hyperpolarized 13C.
- 2007
-
Ingår i: Magnetic Resonance in Medicine. - : Wiley. - 1522-2594 .- 0740-3194. ; 57:6, s. 1140-1147
-
Tidskriftsartikel (refereegranskat)abstract
- nterventional procedures in MRI can be performed preclinically using active or passive catheter-tracking methods. A novel passive nonproton technique is suggested that uses a catheter filled with a hyperpolarized C-13 contrast agent. A prototype three-lumen catheter was built with two closed lumens containing a flowing hyperpolarized C-13 contrast agent. Entire-length C-13 catheter projection visualization could be performed in vivo with a catheter SNR of similar to 80, one dual projection frame per similar to 700 ms, and an in-plane resolution of 2 x 2 mm(2) while traveling through the aorta of a pig. The traveling path of the C-13 catheter was visualized after back-projection catheter reconstruction and after image fusion with an anatomical offline proton road map. Catheter length visualization was aided by an oblique planar visualization mode. The high catheter signal demonstrated, together with the entire catheter length visualization and high surrounding soft-tissue contrast, warrants further development into a real-time technique.
|
|
| 22. |
- Månsson, Sven, et al.
(författare)
-
13C imaging-a new diagnostic platform.
- 2006
-
Ingår i: European Radiology. - : Springer Science and Business Media LLC. - 0938-7994 .- 1432-1084. ; 16:1, s. 57-67
-
Tidskriftsartikel (refereegranskat)abstract
- he evolution of magnetic resonance imaging (MRI) has been astounding since the early 1980s, and a broad range of applications has emerged. To date, clinical imaging of nuclei other than protons has been precluded for reasons of sensitivity. However, with the recent development of hyperpolarization techniques, the signal from a given number of nuclei can be increased as much as 100,000 times, sufficient to enable imaging of nonproton nuclei. Technically, imaging of hyperpolarized nuclei offers several unique properties, such as complete lack of background signal and possibility for local and permanent destruction of the signal by means of radio frequency (RF) pulses. These properties allow for improved as well as new techniques within several application areas. Diagnostically, the injected compounds can visualize information about flow, perfusion, excretory function, and metabolic status. In this review article, we explain the concept of hyperpolarization and the techniques to hyperpolarize 13C. An overview of results obtained within angiography, perfusion, and catheter tracking is given, together with a discussion of the particular advantages and limitations. Finally, possible future directions of hyperpolarized 13C MRI are pointed out.
|
|
| 23. |
- Nyström, Henrik, 1977, et al.
(författare)
-
Platelet-derived growth factor B retention is essential for development of normal structure and function of conduit vessels and capillaries
- 2006
-
Ingår i: Cardiovasc Res. - : Oxford University Press (OUP). - 0008-6363. ; 71:3, s. 557-65
-
Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: Extracellular retention of PDGF-B has been proposed to play an important role in PDGF-B signalling. We used the PDGF-B retention motif knockout mouse (RetKO) to study the effects of retention motif deletion on development of micro- and macrovascular structure and function. METHODS: Passive and active properties of conduit vessels were studied using myograph techniques and histological examination. Capillary structure and function was studied using measurements of capillary density in skeletal muscle and by assessing aerobic physical performance in a treadmill setup. Cardiac function was assessed using echocardiography. RESULTS: Myograph experiments revealed an increased diameter and stiffness of the aorta in RetKO. Histological examination showed increased media collagen content and a decreased number of aortic wall layers, however with a similar number of vascular smooth muscle cells. This outward eutrophic remodelling of the aorta was accompanied by endothelial dysfunction. RetKO showed decreased capillary density in skeletal muscle and signs of a defective delivery of capillary oxygen to skeletal muscle, as shown by a decreased physical performance. In RetKO mice, echocardiography revealed an adaptive eccentric cardiac hypertrophy. CONCLUSION: We conclude that retention of PDGF-B during development is essential for a normal conduit vessel function in the adult mouse. Furthermore, PDGF-B retention is also necessary for the development of an adequate capillary density, and thereby for a normal oxygen delivery to skeletal muscle. The lack of primary effects on cardiac function supports the redundant role of PDGF-B in cardiac development.
|
|
| 24. |
|
|
| 25. |
- Rauter, P., et al.
(författare)
-
Direct determination of ultrafast intersubband hole relaxation times in voltage biased SiGe quantum wells by a density matrix interpretation of femtosecond resolved photocurrent experiments
- 2007
-
Ingår i: New Journal of Physics. - : Institute of Physics (IoP) and Deutsche Physikalische Gesellschaft. - 1367-2630. ; 9
-
Tidskriftsartikel (refereegranskat)abstract
- We report the quantitative and direct determination of hole intersubband relaxation times in a voltage biased SiGe heterostructure using density matrix calculations applied to a four-level system in order to interpret photocurrent (PC) pump-pump experiments. One consistent set of parameters allows the simulation of two kinds of experiments, namely pump-pump photocurrent experiments at a free electron laser (wavelength 7.9 mu m) and the laser-power dependence of the PC signal. This strongly confirms the high reliability of these parameter values, of which the most interesting in respect to Si based quantum cascade laser development is the extracted heavy-hole relaxation time. The simulations show that this relaxation time directly determines the experimentally observed decay of the pump-pump photocurrent signal as a function of the delay time. For a heavy hole intersubband spacing of 160 meV, a value of 550 fs was obtained. The experimental method was further applied to determine the LH1-HH1 relaxation time of a second sample with a transition energy below the optical phonon energy. The observed relaxation time of 16 ps is consistent with the value found for the same structure by transmission pump-probe experiments.
|
|
| 26. |
- Shi, Ming, et al.
(författare)
-
Coherent d-wave superconducting gap in underdoped La2-xSrxCuO4 by angle-resolved photoemission spectroscopy
- 2008
-
Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 101:4, s. 047002-
-
Tidskriftsartikel (refereegranskat)abstract
- We present angle-resolved photoemission spectroscopy data on moderately underdoped La1.855Sr0.145CuO4 at temperatures below and above the superconducting transition temperature. Unlike previous studies of this material, we observe sharp spectral peaks along the entire underlying Fermi surface in the superconducting state. These peaks trace out an energy gap that follows a simple d-wave form, with a maximum superconducting gap of 14 meV. Our results are consistent with a single gap picture for the cuprates. Furthermore our data on the even more underdoped sample La1.895Sr0.105CuO4 also show sharp spectral peaks, even at the antinode, with a maximum superconducting gap of 26 meV.
|
|
| 27. |
- Wang, X., et al.
(författare)
-
Reliability analysis and evaluation of gas supply system
- 2009
-
Ingår i: ICMET'09 - Proceedings of the 2009 International Conference on Mechanical and Electrical Technology. - Beijing. - 9780791802946 ; , s. 245-249
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- In this paper, the reliability model and the evaluation methods were neatly used with combining the engineering practice of the noise laboratory supply system, and this study give a quantitative evaluation result of the reliability system. It provides the scientific basis for improving the engineering design and increasing the reliability. This research results can be extended to similar projects, such as fuel supply system. From an engineering point of view, it is an innovation that the filter in the system is identified to be a "series - parallel mixed" structure by considering its physical structure and performance requirement.
|
|
| 28. |
|
|
| 29. |
- Zhao, Ming, et al.
(författare)
-
Low-temperature molecular beam epitaxy growth of Si/SiGe THz quantum cascade structures on virtual substrates
- 2006
-
Ingår i: Thin Solid Films. - : Elsevier BV. - 0040-6090. ; 508:1-2, s. 24-28
-
Tidskriftsartikel (refereegranskat)abstract
- Si/SiGe quantum cascade structures containing superlattice up to 100 periods have been grown on SiGe virtual substrates by using solid-source molecular beam epitaxy at low temperature. The surface morphology and structural properties of the grown samples were characterized using various experimental techniques. It has been concluded that the structures were completely symmetrically strained with high crystalline quality, precise layer parameters, and excellent reproducibility. Electroluminescence was observed with peaked intensity at 3 THz at both 4 and 40 K, which agrees very well with expected interwell intersubband transition according to the design.
|
|
| 30. |
- Zhao, Ming, et al.
(författare)
-
Molecular beam epitaxy growth of Si/SiGe bound-to-continuum quantum cascade structures for THz emission
- 2008
-
Ingår i: Thin Solid Films. - : Elsevier BV. - 0040-6090 .- 1879-2731. ; 517:1, s. 34-37
-
Tidskriftsartikel (refereegranskat)abstract
- A Si/SiGe bound-to-continuum quantum cascade design for THz emission was grown using solid-source molecular beam epitaxy on Si0.8Ge0.2 virtual substrates. The growth parameters were carefully studied and several samples with different boron doping concentrations were grown at optimized conditions. Extensive material characterizations revealed a high crystalline quality of the grown structures with an excellent growth control. Layer undulations resulting from a nonuniform strain field, introduced by high doping concentration, were observed. The device characterizations suggested that a modification on the design was needed in order to enhance the THz emission.
|
|
| 31. |
- Zhou, Zong-ke, et al.
(författare)
-
No Increased Migration in Cups with Ceramic-on-Ceramic Bearing : An RSA Study
- 2006
-
Ingår i: Clinical Orthopaedics and Related Research. - : Ovid Technologies (Wolters Kluwer Health). - 0009-921X .- 1528-1132. ; :448, s. 39-45
-
Tidskriftsartikel (refereegranskat)abstract
- Ceramic-on-ceramic hip replacements might stress the bone interface more than a metal-polyethylene because of material stiffness, microseparation, and sensitivity to impingement. To ascertain whether this potentially increased stress caused an increased cup migration we compared a ceramic-on-ceramic with a metal-on-polyethylene implant for cup migration. Sixty one patients (61 hips) undergoing THA for osteoarthritis were randomized to ceramic on ceramic (Ce/Ce) or cobalt-chromium on cross-linked polyethylene bearings (PE) in the same uncemented cup shell. Migrationwas followed with RSA. At 2 years we observed similar mean cup translations in the 3 directions (0.07–0.40 mm vs. 0.05–0.31 mm, Ce/Ce vs. PE), as well as similar rotations around the 3 axes (0.31–0.92° vs. 0.57–1.40°). WOMAC and SF-36 scores were also similar and no radiolucent lines or osteolysis found. The large migration seen in some cups in both implant groups will require close monitoring to ascertain the reasons. Mean proximal wear of the polyethylene liners measured 0.016 mm between 2 and 24 months. Our data suggest there is no increased cup migration in the ceramic-on-ceramic implant compared with the metal-on-polyethylene, and they seem an equally safe choice. However, the low wear measured with the more versatile and less expensive cross-linked polyethylene makes it a strong contender. Levels of Evidence: Therapeutic Level I. See the Guidelinesfor Authors for a complete description of levels of evidence.
|
|
