| 11. |
- Lind, Monica, et al.
(författare)
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The dioxin-like pollutant PCB 126 (3,3',4,4',5-pentachlorobiphenyl) affects risk factors for cardiovascular disease in female rats
- 2004
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Ingår i: Toxicology Letters. - : Elsevier BV. - 0378-4274 .- 1879-3169. ; 150:3, s. 293-299
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Tidskriftsartikel (refereegranskat)abstract
- Epidemiological studies suggest that exposure to persistent organic pollutants such as organochlorines might induce cardiovascular disorders and diabetes. Some of these organochlorines, such as dioxins and some dioxin-like PCBs, have been characterised as anti-estrogenic due to their inhibition of estrogenic-induced responses. In the present pilot study, 40 female rats were subjected to either exposure to the dioxin-like 3,3',4,4',5-pentachlorobiphenyl (PCB 126) or vehicle, as well as ovariectomy (OVX) or sham operation in a 2 x 2 factorial design over 12 weeks to explore potential interactions between estrogen status and PCB 126 exposure on cardiovascular risk factors. PCB 126 increased heart weight and serum cholesterol levels in both groups. PCB 126 increased blood pressure in the sham-operated animals only. In conclusion, PCB 126 exposure in female rats resulted in effects on cardiovascular risk factors, such as serum cholesterol, blood pressure, and heart weight. Of these effects of PCB 126, the increase in blood pressure was dependent on estrogen status.
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| 12. |
- Lind, Monica, et al.
(författare)
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Torsional testing and peripheral quantitative computed tomography in rat humerus
- 2001
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Ingår i: Bone. - : Elsevier BV. - 8756-3282 .- 1873-2763. ; 29:3, s. 265-270
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Tidskriftsartikel (refereegranskat)abstract
- Peripheral quantitative computed tomography (pQCT) is a noninvasive method mainly used to evaluate the densitometric and geometric properties of bone. In the present study, we evaluate the different variables provided by pQCT examination and their ability to predict the mechanical strength properties of the rat humerus. Humeri from 68 female rats were utilized. These humeri represented bone with a wide range of mechanical and densitometric properties as well as geometric dimensions. Various characteristics, such as volumetric cortical density, total mineral content, cortical thickness, total cross-sectional area, cortical area, and polar strength strain index (SSI), were measured by pQCT. The reproducibility of these measurements was good, with a coefficient of variation (CV) ranging from 0.8% to 4.9%. Bone composition (e.g., ash weight, water content, and inorganic content) and bone dimensions (e.g., length, waist, and volume) were also determined. The mechanical properties (maximum torque, torsion at failure, and stiffness) were measured by torsional testing. Stepwise multiple linear regression was performed to identify the best explanatory variables for each mechanical parameter. Total cross-sectional area and polar SSI were equally well correlated to stiffness (r = 0.57, p < 0.001), whereas ash weight was superior to the pQCT variables to explain maximum torque (r = 0.42, p < 0.001). No other independent pQCT variable entered the two models in the stepwise regression analysis. It was found to be feasible to measure properties of the rat humerus with pQCT. Cross-sectional area and the polar SSI were shown to be the best explanatory variables for stiffness, whereas ash weight was the best predictor for maximum torque.
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| 13. |
- Lind, Peter, et al.
(författare)
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Risk of myocardial infarction in relation to plasma levels of homocysteine and inflammation-sensitive proteins: a long-term nested case-control study.
- 2003
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Ingår i: Angiology. - 0003-3197. ; 54:4, s. 401-410
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Tidskriftsartikel (refereegranskat)abstract
- Several studies have found that the homocysteine plasma level is associated with cardiovascular disease. The authors previously described a relationship between concentrations of fibrinogen and other inflammation-sensitive plasma proteins, namely, alpha1-antitrypsin, ceruloplasmin, haptoglobin, and orosomucoid (alpha1-acid glucoprotein) and the incidence of myocardial infarction (MI). Whether levels of these proteins are related to homocysteine has not been clarified. The aim of this study was to investigate whether a supposed relationship between homocysteine in plasma and the occurrence of MI is modified by these inflammation-sensitive proteins. A nested case-control study was designed, comprising 241 cases of MI, with a mean age of 48 years at baseline, and 241 controls matched for age, month of examination, and duration of follow-up. The mean homocysteine concentration did not differ between cases and controls and there was no association between the baseline homocysteine level and the time lapse before the occurrence of the MI. For the cases, there was no correlation between homocysteine and any of the measured proteins, but for the controls, homocysteine was weakly but significantly negatively correlated to haptoglobin and ceruloplasmin and slightly positively correlated to albumin. For the separated groups of cases and controls there was no association between the number of inflammation-sensitive proteins in the top quartiles and homocysteine concentration. In this population-based, prospective cohort study the occurrence of MI had no relationship to homocysteine baseline plasma level. Furthermore, there was no strong association between homocysteine and the concentrations of any of these inflammation-sensitive proteins.
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| 14. |
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| 15. |
- Wernersson, Lars-Erik, et al.
(författare)
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Attractive potential around a buried metallic gate in a Schottky Collector Hot Electron Transistor
- 2002
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Ingår i: Institute of Physics Conference Series. - 0951-3248. ; 170, s. 81-85
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Tidskriftsartikel (refereegranskat)abstract
- We report on the formation of an attractive potential around buried metal wires in a novel design for the Hot Electron Transistor (HET). In this device, the doped base layer in the HET is replaced by an embedded metal grating, which is forward biased beyond flat band conditions in order to efficiently extract carriers from the emitter into the active region. These carriers are collected in a Schottky Collector contact. By tuning the gate and collector voltages, the potential profile around the wires can be repulsive as well as attractive. This is a key result for the realisation of a Biprism device.
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| 16. |
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| 17. |
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| 18. |
- Annuk, Margus, et al.
(författare)
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Cyclooxygenase inhibition improves endothelium-dependent vasodilatation in patients with chronic renal failure
- 2002
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Ingår i: Nephrology, Dialysis and Transplantation. - : Oxford University Press (OUP). - 0931-0509 .- 1460-2385. ; 17:12, s. 2159-2163
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Some studies have demonstrated beneficial effects of L-arginine as a substrate for nitric oxide synthesis, and diclofenac as an inhibitor of cyclooxygenase (COX)-derived vasoconstrictive agents on vascular responses in humans during several pathological conditions. The aim of the present study was to investigate the acute effects of L-arginine and diclofenac on endothelium-dependent vasodilatation (EDV) and endothelium-independent vasodilatation (EIDV) in patients with chronic renal failure (CRF). METHODS: Effects of L-arginine and diclofenac on EDV and EIDV were measured in 15 patients with CRF and in 15 healthy controls by means of forearm blood flow measurements with venous occlusion plethysmography during local intra-arterial infusions of methacholine (2 and 4 micro g/min evaluating EDV) and sodium nitroprusside (5 and 10 micro g/min evaluating EIDV). RESULTS: L-Arginine infusion increased methacholine-induced vasodilatation both in patients with CRF and healthy controls. Diclofenac infusion increased methacholine-induced vasodilatation only in patients with CRF. There was no significant change in nitroprusside-induced vasodilatation after L-arginine and diclofenac infusions both in patients with CRF and healthy controls. CONCLUSIONS: These results suggest that COX inhibition reduces the levels of a prostanoid-derived vasoconstrictive agent contributing to the impaired EDV in patients with CRF, while in this age group L-arginine improves EDV regardless of renal function.
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| 19. |
- Annuk, Margus, et al.
(författare)
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Impaired endothelium-dependent vasodilatation in renal failure in humans
- 2001
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Ingår i: Nephrology, Dialysis and Transplantation. - : Oxford University Press (OUP). - 0931-0509 .- 1460-2385. ; 16:2, s. 302-306
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The main causes of death in patients with chronic renal failure (CRF) are cardiovascular complications. The aim of the present study was to compare endothelium-dependent vasodilatation (EDV) in patients with chronic renal failure with a control population controlling for hypertension, diabetes mellitus and hypercholesterolaemia. METHODS: Fifty-six patients with moderate CRF (mean creatinine clearance 29.4 ml/min/1.73 m(2)) underwent evaluation of EDV and endothelium-independent vasodilatation (EIDV) by means of forearm blood flow (FBF) measurements with venous occlusion plethysmography during local intra-arterial infusions of methacholine (Mch, 2 and 4 microg/min evaluating EDV) and sodium nitroprusside (SNP, 5 and 10 microg/min evaluating EIDV). Fifty-six control subjects without renal impairment underwent the same investigation. RESULTS: Infusion of Mch increased FBF significantly less in patients with renal failure than in controls (198 vs 374%, P<0.001), whereas no significant difference was seen regarding the vasodilatation induced by SNP (278 vs 269%). The differences in EDV between the groups were still significant after controlling for hypertension, blood glucose, and serum cholesterol in multiple regression analysis (P<0.001). EDV was related to serum creatinine (r=-0.37, P<0.01), creatinine clearance (r=0.45, P<0.005) and to serum triglyceride levels (r=-0.29, P<0.005) in the CRF group. CONCLUSIONS: Patients with moderate CRF have an impaired EDV even after correction for traditional cardiovascular risk factors and this impairment is related to the degree of renal failure.
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| 20. |
- Annuk, Margus, et al.
(författare)
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Oxidative stress and endothelial function in chronic renal failure
- 2001
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Ingår i: Journal of the American Society of Nephrology. - 1046-6673 .- 1533-3450. ; 12:12, s. 2747-2752
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- This study aimed to investigate the relationship between oxidative stress and endothelium-dependent vasodilation in patients with chronic renal failure (CRF). Thirty-seven patients with CRF underwent evaluation of endothelium-dependent vasodilation and endothelium-independent vasodilation by means of forearm blood flow measurements with venous occlusion plethysmography during local intra-arterial infusions of methacholine (evaluating endothelium-dependent vasodilation) and sodium nitroprusside (evaluating endothelium-independent vasodilation). Lag phase of lipoprotein fraction to oxidation, total antioxidative activity, diene conjugates, thiobarbituric acid reactive substances, lipid hydroperoxide, reduced glutathione (GSH), oxidized GSH (GSSG), and the GSH redox ratio (GSSG/GSH) were all measured as markers of oxidative stress. Two groups of healthy subjects (61 and 37 subjects, respectively) were used as controls. In one group, oxidative stress markers were measured, whereas endothelium-dependent vasodilation and endothelium-independent vasodilation were assessed in the other group. Compared with controls, the patients with renal insufficiency had an impaired endothelium-dependent vasodilation, a shorter lag phase of lipoprotein fraction, and higher levels of diene conjugates, lipid hydroperoxide, and GSSG levels. The GSSG/GSH ratio was lower in patients with CRF. Endothelium-dependent vasodilation was positively correlated with total antioxidative activity (r = 0.41, P = 0.016), GSH (r = 0.44, P < 0.0098), and lag phase of LDL (r = 0.35, P = 0.036) and negatively correlated with GSSG (r = -0.40, P < 0.018), GSSG/GSH (r = -0.47, P = 0.0057), and diene conjugates (r = -0.53 P < 0.0015) in patients with CRF. These results show that an impaired endothelium vasodilation function and oxidative stress are related to each other in patients with CRF.
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