| 1. |
- Bergström, Hans, 1952-, et al.
(author)
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Wind power in forests : wind and effects on loads
- 2013
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Reports (other academic/artistic)abstract
- Within the project V-312, Wind power in forests, researchers and a PhD student at Uppsala University, WeatherTech Scandinavia, the Royal Institute of Technology (KTH), DTU Wind Energy in Denmark and Teknikgruppen have been cooperating. Within the project atmospheric turbulence measurements with high vertical resolution have been done, also down between the trees, to make it possible to give better theoretical descriptions of the observed properties. Several mesoscale models have also been used to model the above forest winds. The atmospheric measurements have been complemented by wind tunnel measurements using a wind tunnel floor designed with small cylindrical wooden sticks that should simulate the effect of the trees generating a known momentum sink able to affect the flow. The combined new knowledge about the forest boundary layer wind and turbulence properties have been used as input to a dynamical wind turbine computer model, used to simulate the turbine load response to the turbulent wind field.
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| 2. |
- Bäck, Karolina, 1981-
(author)
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Interaction between insulin and IGF-I receptors in insulin sensitive and insulin resistant cells and tissues
- 2011
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Doctoral thesis (other academic/artistic)abstract
- Insulin and insulin-like growth factor I (IGF-I) are two related peptides with similar structure. They mediate their effects by binding to their respective receptor, the insulin receptor (IR) and the IGF-I receptor (IGF-IR) and induce intracellular signalling cascades resulting in metabolic or mitogenic effects. The relative abundance of IR and IGF-IR is of importance for the type of effect that is the outcome of the signal. There are few studies investigating the relative receptor abundance and its effects in human cells and tissues.In this thesis we wanted to study abundance and regulation of insulin and IGF-I receptors in different human cells and tissues and examine the effects of variations in insulin and IGF-I receptor abundance between different cells and tissues.We examined IR and IGF-IR gene and protein expression and the effects of insulin and IGF-I on receptor phosphorylation, DNA synthesis and glucose transport.Our results show that there is a large variation in the distribution of IR and IGF-IR in different human cells and tissues. Renal artery intima-media expressed predominantly IGF-IR while in liver IR was the predominant receptor type.Differentiation of human preadipocytes results in a change in relative expression of IGF-IR to IR. Mature adipocytes express almost 10-fold more IR than IGF-IR while preadipocytes express almost the same amounts of both receptors. Mature tissues, such as liver, skeletal muscle, myometrium and renal artery intima-media, express predominantly IR-B. Preadipocytes express IR-A and the expression of IR-B is induced during differentiation.We could show the presence of insulin/IGF-I hybrid receptors in preadipocytes but not in mature adipocytes. Cultured endothelial cells express mostly IGF-IR and insulin/IGF-I hybrid receptors and these cells respond mainly to IGF-I. Due to the large abundance of IR mature adipocytes are sensitive to insulin but insensitive to IGF-I whereas preadipocytes expressing equal amounts of both receptors respond to both insulin and IGF-I. Insulin and IGF-I are only partial agonists to each other’s receptors in human preadipocytes and adipocytes.The overall results indicate that differential expression of IGF-IR and IR is a key mechanism in regulation of growth and metabolism.
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| 3. |
- Hedman, Christina, 1964-, et al.
(author)
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Residual β-cell function more than glycemic control determines abnormalities of the insulin-like growth factor system in type 1 diabetes
- 2004
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In: Journal of Clinical Endocrinology and Metabolism. - : The Endocrine Society. - 0021-972X .- 1945-7197. ; 89:12, s. 6305-6309
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Journal article (peer-reviewed)abstract
- The GH-IGF-I axis is disturbed in patients with type 1 diabetes. Our aim was to investigate whether abnormalities are found in patients in very good glycemic control and, if so, to estimate the role of residual β-cell function. Patients with hemoglobin A 1c (HbA 1c) less than 6% (reference range, 3.6-5.4%) were selected for the study. Twenty-two men and 24 women, aged 41.3 ± 13.8 yr (mean ± SD), with a diabetes duration of 17.8 ± 14.6 yr participated. Healthy controls (15 women and nine men), aged 41.3 ± 13.0 yr, were also studied. Overnight fasting serum samples were analyzed for HbA 1c, C peptide, free and total IGFs, IGF-binding proteins (IGFBPs), GH-binding protein, and IGFBP-3 proteolysis. HbA 1c was 5.6 ± 0.5% in patients and 4.4 ± 0.3% in controls. Total IGF-I was 148 ± 7 μg/liter in patients and 178 ± 9 μg/liter in controls (P < 0.001). Free IGF-I, total IGF-II, IGFBP-3, and GH-binding protein were lower, whereas IGFBP-1, IGFBP-1-bound IGF-I, and IGFBP-2 were elevated compared with control values. Patients with detectable C peptide (≥100 pmol/liter) had higher levels of total IGF-I, free IGF-I, and total IGF-II and lower levels of IGFBP-1 and IGFBP-2 than those with an undetectable C peptide level despite having identical average HbA 1c. IGFBP-3 proteolysis did not differ between patients and controls. Despite very good glycemic control, patients with type 1 diabetes and no endogenous insulin production have low free and total IGF-I. Residual β-cell function, therefore, seems more important for the disturbances in the IGF system than good metabolic control per se, suggesting that portal insulin delivery is needed to normalize the IGF system.
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| 4. |
- Andersson, Peter, 1957-, et al.
(author)
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Insulin-like growth factor binding proteins-2 to -6 are expressed by human vascular smooth muscle cells.
- 1999
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In: Journal of Endocrinology. - 0022-0795 .- 1479-6805. ; 163:2, s. 281-288
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Journal article (peer-reviewed)abstract
- We have investigated the expression and secretion of insulin-like growth factor binding proteins (IGFBPs-1 to -6) in human vascular smooth muscle cells (hVSMCs) cultured from human renal arteries. Solution hybridization was used to determine IGFBP nRNA levels and Western immunoblot to detect the corresponding peptides. The hVSMCs expressed mRNAs for IGFBPs-2 to -6, IGFBP-1 mRNA was not detected. IGFBPs-3, -4 and -6 mRNAs were the most abundant, IGFBP-5 was also highly expressed, whereas the IGFBP-2 mRNA was just above the limit of detection. Serum starvation for 48 h significantly decreased the mRNA levels of IGFBPs-2 to -5 and tended to decrease IGFBP-6 mRNA also. IGFBPs-2, -4, -5 and -6 peptides could be detected in conditioned medium, but IGFBP-3 peptide was not detected. IGFBP-4 was the only peptide detected without any concentration step. Low-molecular-mass immunoreactive degradation products were found for IGFBPs-2 and -4. Exogenous IGFBPs-1, -3 and -4 in concentrations of 50 ng/ml inhibited DNA synthesis induced by 1 nM IGF-I, whereas IGFBPs-2, -5 and -6 had no significant inhibitory effects at this concentration. We conclude from these results that all IGFBPs except IGFBP-1 are expressed in hVSMC. Our results indicate that locally produced, in addition to circulating,, IGFBPs may have an important role in the regulation of hVSMC.
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| 5. |
- Arnqvist, Hans, et al.
(author)
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Early increase in HbA1c trajectory predicts development of severe microangiopathy in patients with type 1 diabetes: the VISS study
- 2024
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In: BMJ Open Diabetes Research & Care. - : BMJ PUBLISHING GROUP. - 2052-4897. ; 12:3
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Journal article (peer-reviewed)abstract
- Introduction To study the HbA1c trajectory from the time of diagnosis to examine if patients at the greatest risk for severe microangiopathy can be identified early allowing clinicians to intervene as soon as possible to avoid complications. Research design and methods In a population-based observational study, 447 patients diagnosed with type 1 diabetes before 35 years of age, 1983-1987, were followed from diagnosis until 2019. Mean HbA1c was calculated each year for each patient. Severe diabetic microangiopathy was defined as proliferative diabetic retinopathy (PDR) or macroalbuminuria (nephropathy). Results After 32 years, 27% had developed PDR and 8% macroalbuminuria. Patients with weighted HbA1c (wHbA1c); <57 mmol/mol; <7.4% did not develop PDR or macroalbuminuria. The HbA1c trajectories for patients developing PDR and macroalbuminuria follow separate courses early on and stay separated for 32 years during the follow-up. Patients without severe complications show an initial dip, after which HbA1c slowly increases. HbA1c in patients with severe complications directly rises to a high level within a few years. Mean HbA1c calculated for the period 5-8 years after diabetes onset strongly predicts the development of severe complications. Females with childhood-onset diabetes exhibit a high peak in HbA1c during adolescence associated with higher wHbA1c and higher prevalence of PDR. Conclusions The HbA1c trajectory from diabetes onset shows that mean HbA1c for the period 5-8 years after diagnosis strongly predicts severe microangiopathy. Females with childhood-onset diabetes exhibit a high peak in HbA1c during adolescence associated with higher wHbA1c and a higher prevalence of PDR.
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| 6. |
- Arnqvist, Hans, et al.
(author)
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Impact of HbA(1c) Followed 32 Years From Diagnosis of Type 1 Diabetes on Development of Severe Retinopathy and Nephropathy: The VISS Study
- 2022
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In: Diabetes Care. - : AMER DIABETES ASSOC. - 0149-5992 .- 1935-5548. ; 45:11, s. 2675-2682
-
Journal article (peer-reviewed)abstract
- OBJECTIVE To evaluate HbA(1c) followed from diagnosis, as a predictor of severe microvascular complications (i.e., proliferative diabetic retinopathy [PDR] and nephropathy [macroalbuminuria]). RESEARCH DESIGN AND METHODS In a population-based observational study, 447 patients diagnosed with type 1 diabetes before 35 years of age from 1983 to 1987 in southeast Sweden were followed from diagnosis until 2019. Long-term weighted mean HbA(1c) (wHbA(1c)) was calculated by integrating the area under all HbA(1c) values. Complications were analyzed in relation to wHbA(1c) categorized into five levels. RESULTS After 32 years, 9% had no retinopathy, 64% non-PDR, and 27% PDR, and 83% had no microalbuminuria, 9% microalbuminuria, and 8% macroalbuminuria. Patients with near-normal wHbA(1c) did not develop PDR or macroalbuminuria. The lowest wHbA(1c) values associated with development of PDR and nephropathy (macroalbuminuria) were 7.3% (56 mmol/mol) and 8.1% (65 mmol/mol), respectively. The prevalence of PDR and macroalbuminuria increased with increasing wHbA(1c), being 74% and 44% in the highest category, wHbA(1c) >9.5% (>80 mmol/mol). In comparison with the follow-up done after 20-24 years duration, the prevalence of PDR had increased from 14 to 27% and macroalbuminuria from 4 to 8%, and both appeared at lower wHbA(1c) values. CONCLUSIONS wHbA(1c) followed from diagnosis is a very strong biomarker for PDR and nephropathy, the prevalence of both still increasing 32 years after diagnosis. To avoid PDR and macroalbuminuria in patients with type 1 diabetes, an HbA(1c) <7.0% (53 mmol/mol) and as normal as possible should be recommended when achievable without severe hypoglycemia and with good quality of life.
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| 7. |
- Arnqvist, Hans
(author)
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The role of IGF-system in vascular insulin resistance
- 2008
-
In: Hormone and Metabolic Research. - : Georg Thieme Verlag KG. - 0018-5043 .- 1439-4286. ; 40:9, s. 588-592
-
Research review (peer-reviewed)abstract
- Insulin and IGF-I are closely related peptides, which interact by several mechanisms. In high supraphysiological concentrations (=10-8M), they cross-react with each other's receptors with 100- to 1000-fold lower affinity than with their cognate receptors. This can cause confusion, since in many in vitro studies, insulin has been used in high unphysiological concentrations, which activate IGF-I receptors. Due to the differences in affinity, insulin and IGF-I probably do not activate each other's receptors in vivo. IGF-I receptors are several-fold more abundant than insulin receptors in human micro- and macrovascular endothelial cells and in human vascular smooth muscle cells. Both insulin and IGF-I receptor protein can be demonstrated and they are activated by their cognate ligand at physiological concentrations of 10-9-10-10M. In vascular smooth muscle cells, IGF-I but not insulin stimulates metabolism and growth. IGF-I stimulates DNA-synthesis and growth in microvascular endothelial cells, but neither insulin nor IGF-I have any effect on macrovascular endothelial cells. Both insulin and IGF-I have been shown to stimulate nitric oxide production in endothelial cells, but only the effect of IGF-I was obtained at a physiological concentration. In both endothelial and vascular smooth muscle cells, insulin and IGF-I receptors occur as insulin/ICF-I hybrid receptors with high affinity to IGF-I and low for insulin. Due to the low number of insulin receptors and the presence of hybrid receptors the insulin receptor signal is probably too attenuated to elicit biological effects, explaining the insulin resistance of vascular cells in vitro. In vivo both insulin and IGF-I have been reported to increase muscle blood flow in physiological concentrations. Whether this is due to direct effects on endothelial cells or indirectly induced is not clear. The effect of insulin is attenuated by insulin resistance. In conclusion, the in vitro data suggest that endothelial cells and vascular smooth muscle cells are sensitive to IGF-I, but insensitive to insulin, and this is due to a preponderance of IGF-I receptors and the presence of insulin/IGF-l hybrid receptors. © Georg Thieme Verlag KG Stuttgart · New York.
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| 8. |
- Arnqvist, Hans, et al.
(author)
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Vitamin D status in longstanding type 1 diabetes and controls. Association with upper extremity impairments
- 2023
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In: Upsala Journal of Medical Sciences. - : UPSALA MED SOC. - 0300-9734 .- 2000-1967. ; 128:1
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Journal article (peer-reviewed)abstract
- Background: Patients with type 1 diabetes have a high prevalence of upper extremity impairments (UEIs), such as frozen shoulder, carpal tunnel syndrome, and trigger finger. The UEIs are strongly associated with activity limitations and impaired quality of life. The etiology of the UEI is not clear. Vitamin D deficiency has been considered to play a role in the pathogenesis of type 1 diabetes and in the development of macro- and microvascular complications in diabetes. Aim: To characterize vitamin D status in a large population of patients with type 1 diabetes, if vitamin D deficiency is associated with metabolic factors and possible association with UEI. Material and methods: Patients who diagnosed before 35 years of age, whose diabetes duration >20 years, and who are not older than 65 years were invited to participate in this cross-sectional case-control, multicenter study. Controls matched for age and sex were obtained from the national population registry. Fasting blood samples were collected and stored at -80 degrees C until analyzed regarding 25-hydroxy-vitamin D (25(OH)D3) by a liquid chromatographic-mass spectrometric method (LC-MS/MS). Results: Vitamin D levels varied with season as expected in the northern hemisphere. The association between 25(OH)D3 and clinical variables was analyzed in a univariate general linear model, which indicated no difference in 25(OH)D3 in men with and without diabetes but higher values in women with diabetes. About 30% of both patients and controls had vitamin D deficiency (=50 nmol/L). Analyzed by binary logistic regression UEIs was not associated with 25(OH)D3 levels. In both patients and controls, 25(OH)D3 was correlated to apolipoprotein A1 (r = 0.153; 0.220, P < 0.001). Conclusion: In patients with type 1 diabetes and a duration of 20 years or more, vitamin D level is not lower than in nondiabetic controls and is not associated with UEIs.
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| 9. |
- Arnqvist, Johan, et al.
(author)
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Canopy waves, observations and predictions from lineartheory
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Other publication (other academic/artistic)abstract
- In this paper the existence of canopy waves is examined using measurements from a 138 m high tower placed in a forest. Characteristics of the waves are examined in relation to wind energy. Using wavelet analysis it is shown that when the wave signal is clear, the phase lag between horizontal and vertical velocity is close to 90 degrees, which limits the contribution of the waves to themomentum flux. Results from numerical solution of linear wave equations is shown to agree with measurements in terms of wave period and the vertical shape of the wave amplitude. Linear analysis and measurements suggests that Kelvin-Helmholtz instability causes unstable wave growth and that the most unstable wave number normally has a period of 10-100 s. In addition to the Kelvin-Helmholtz instability, the linear analysis predicts that instabilities of the Holmboe kind, with higher frequency, can develop over forests in certain conditions.
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| 10. |
- Arnqvist, Johan, et al.
(author)
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Examination of the mechanism behind observed canopy waves
- 2016
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In: Agricultural and Forest Meteorology. - : Elsevier BV. - 0168-1923 .- 1873-2240. ; 218, s. 196-203
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Journal article (peer-reviewed)abstract
- In this paper, we document the existence of wave-like motions above a forest canopy using data taken from a 138 m high tower placed within a forest Characteristics of the waves are examined in relation to their possible effects on wind energy. It is shown that when the wave signal is relatively clean, the phase lag between horizontal and vertical velocity is close to 90, which limits the contribution of the waves to the downward momentum flux. Numerical solutions of the linear wave equations agree with measurements in terms of wave period and the vertical shape of the wave amplitude. Linear analysis show that shear instability is the cause of unstable wave growth, and that the fastest growing unstable wave number typically has a period of 10-100 s. In addition to the shear instability, the linear analysis predicts that under certain conditions instabilities of the Holmboe kind can develop over forests.
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| 11. |
- Arnqvist, Johan, 1985-, et al.
(author)
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Flux-profile relation with roughness sublayer correction
- 2015
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In: Quarterly Journal of the Royal Meteorological Society. - : Wiley. - 0035-9009 .- 1477-870X. ; 141:689, s. 1191-1197
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Journal article (peer-reviewed)abstract
- Calculation of momentum flux using Monin–Obukhov similarity theory over forested areas is well known to underestimate the flux. Several suggestions of corrections to the standard flux-profile expression have been proposed in order to increase the magnitude of turbulent flux. The aim of this article is to find a simple, analytical representation for the characteristics of the flow within the canopy layer and the surface layer, including the roughness sublayer. A new form of the roughness sublayer correction is proposed, based on the desire to connect the shape of the roughness sublayer correction to forest characteristics. The new flux-profile relation can be used to find the flux or the wind profile whenever simple and fast estimations are needed, as for mesoscale modelling, scalar transport models, or sound propagation models.
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| 12. |
- Arnqvist, Johan, 1985-
(author)
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Mean Wind and Turbulence Conditions in the Boundary Layer above Forests
- 2015
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Doctoral thesis (other academic/artistic)abstract
- As wind turbines have grown, new installation areas become possible. Placing wind turbines in forested landscapes introduce uncertainties to the wind resource estimation. Even though close-to-canopy processes have been studied intensively during the last thirty years, the focus has mostly been on exchange processes and the height span of the studies has been below the rotor of a modern wind turbine.This thesis contains analysis of new measurements from a 138 m high tower in a forested landscape. The previous knowledge of near-canopy processes is extended to the region above the roughness sublayer. It is shown that above the roughness sublayer, the surface layer behaves as over low vegetation, and Monin-Obukhov similarity is shown to hold for several variables. However, in stable stratification, effects that could be linked to the boundary layer depth are shown to be present in the measurements. These include wind turning with height, the behaviour of the turbulence length scale and the curvature of the wind profile.Two new analytical models are presented in the thesis. One is a flux-profile expression in the roughness sublayer, which allows for analytical integration of the wind gradient. The model suggests that the roughness-sublayer effect depends on stratification and that the aerodynamic roughness length changes with stability. A decrease of roughness length in stable stratification is confirmed with a new method to determine the roughness length using measurements from the 138 m tower.The other model determines the spectral tensor in stable stratification using analytical solution to the rapid distortion equations for stratified shear flow, with homogeneous stratification and shear. By using a formulation for the integration time of the distortions of an isotropic spectrum, a model is derived which provides the cross spectra of velocity and temperature at any two given points in space.Finally the existence of waves in the wind over forests is investigated and it is concluded that the Kelvin-Helmholtz instability can create waves which are coherent in time and exist over the entire height span of wind turbine rotors. Linear wave theory is shown to be able to explain certain features of the waves.
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| 13. |
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| 14. |
- Arnqvist, Johan, et al.
(author)
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Wind Statistics from a Forested Landscape
- 2015
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In: Boundary-layer Meteorology. - : Springer Science and Business Media LLC. - 0006-8314 .- 1573-1472. ; 156:1, s. 53-71
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Journal article (peer-reviewed)abstract
- An analysis and interpretation of measurements from a 138-m tall tower located in a forested landscape is presented. Measurement errors and statistical uncertainties are carefully evaluated to ensure high data quality. A 40 wide wind-direction sector is selected as the most representative for large-scale forest conditions, and from that sector first-, second- and third-order statistics, as well as analyses regarding the characteristic length scale, the flux-profile relationship and surface roughness are presented for a wide range of stability conditions. The results are discussed with focus on the validity of different scaling regimes. Significant wind veer, decay of momentum fluxes and reduction in shear length scales with height are observed for all stability classes, indicating the influence of the limited depth of the boundary layer on the measured profiles. Roughness sublayer characteristics are however not detected in the presented analysis. Dimensionless gradients are shown to follow theoretical curves up to 100 m in stable conditions despite surface-layer approximations being invalid. This is attributed to a balance of momentum decay and reduced shear length scale growth with height. The wind profile shows a strong stability dependence of the aerodynamic roughness length, with a 50 % decrease from neutral to stable conditions.
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| 15. |
- Bachrach-Lindström, Margaretha, 1957-, et al.
(author)
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Assessment of nutritional status using biochemical and anthropometric variables in a nutritional intervention study of women with hip fracture
- 2001
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In: Clinical Nutrition. - : Elsevier BV. - 0261-5614 .- 1532-1983. ; 20:3, s. 217-223
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Journal article (peer-reviewed)abstract
- Background & Aims: The aim of this study of women with hip fracture was to describe nutritional status with biochemical markers and anthropometric variables, and to evaluate the effect of nutritional intervention with the intention of increasing protein and energy intake.Methods: The first consecutive 44 women were included, and used as controls. The next 44 were matched for age, fracture and mental state. Anthropometric variables, IGF-I, hormones and serum albumin were collected 4–6 days (baseline), 1 and 3 months after surgery. Twenty-four women filled out a 7-day food record.Results: At baseline, one fourth had BMI <20 kg/m2and subnormal triceps skinfold thickness. Baseline serum albumin, IGF-I and growth hormone levels were low, probably as an acute response to trauma. Women with BMI <20 kg/m2had lower IGF-I levels compared to those with higher BMI. At 3 months, one-third of both groups were protein and energy malnourished. The intervention group obtained higher daily energy percentage from fat but none of the groups reached their calculated energy need.Conclusions: Using biochemical markers in the acute postoperative situation to assess nutritional status is not recommended. The intervention had no impact on anthropometric or biochemical variables.
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| 16. |
- Bakhtadze, Ekaterine, et al.
(author)
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Common variants in the TCF7L2 gene help to differentiate autoimmune from non-autoimmune diabetes in young (15-34 years) but not in middle-aged (40-59 years) diabetic patients
- 2008
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In: Diabetologia. - : Springer Science and Business Media LLC. - 0012-186X .- 1432-0428. ; 51:12, s. 2224-2232
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Journal article (peer-reviewed)abstract
- Type 1 diabetes in children is characterised by autoimmune destruction of pancreatic beta cells and the presence of certain risk genotypes. In adults the same situation is often referred to as latent autoimmune diabetes in adults (LADA). We tested whether genetic markers associated with type 1 or type 2 diabetes could help to discriminate between autoimmune and non-autoimmune diabetes in young (15-34 years) and middle-aged (40-59 years) diabetic patients. In 1,642 young and 1,619 middle-aged patients we determined: (1) HLA-DQB1 genotypes; (2) PTPN22 and INS variable-number tandem repeat (VNTR) polymorphisms; (3) two single nucleotide polymorphisms (rs7903146 and rs10885406) in the TCF7L2 gene; (4) glutamic acid decarboxylase (GAD) and IA-2-protein tyrosine phosphatase-like protein (IA-2) antibodies; and (5) fasting plasma C-peptide. Frequency of risk genotypes HLA-DQB1 (60% vs 25%, p =9.4x10(-34); 45% vs 18%, p= 1.4x10(-16)), PTPN22 CT/TT (34% vs 26%, p=0.0023; 31% vs 23%, p=0.034), INS VNTR class I/I (69% vs 53%, p=1.3x10(-8); 69% vs 51%, p=8.5x10(-5)) and INS VNTR class IIIA/IIIA (75% vs 63%, p=4.3x10(-6); 73% vs 60%, p=0.008) was increased in young and middle-aged GAD antibodies (GADA)-positive compared with GADA-negative patients. The type 2 diabetes-associated genotypes of TCF7L2 CT/TT of rs7903146 were significantly more common in young GADA-negative than in GADA-positive patients (53% vs 43%; p=0.0004). No such difference was seen in middle-aged patients, in whom the frequency of the CT/TT genotypes of TCF7L2 was similarly increased in GADA-negative and GADA-positive groups (55% vs 56%). Common variants in the TCF7L2 gene help to differentiate young but not middle-aged GADA-positive and GADA-negative diabetic patients, suggesting that young GADA-negative patients have type 2 diabetes and that middle-aged GADA-positive patients are different from their young GADA-positive counterparts and share genetic features with type 2 diabetes.
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| 17. |
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| 18. |
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| 19. |
- Bjarnegård, Niclas, et al.
(author)
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Long-term hyperglycaemia impairs vascular smooth muscle cell function in women with type 1 diabetes mellitus
- 2009
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In: DIABETES and VASCULAR DISEASE RESEARCH. - : SAGE Publications. - 1479-1641 .- 1752-8984. ; 6:1, s. 25-31
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Journal article (peer-reviewed)abstract
- Observations of increased stiffness in the elastic aorta in women with diabetes, but not men, emphasise the need for further analysis regarding early abnormalities in arterial wall properties of women with type 1 diabetes mellitus (DM).Ultrasound was used to study the wall properties of the distal brachial artery (BA) in 37 type 1 diabetic women (aged 22-45 years) without evident complications and in 53 controls (C). Blood samples were drawn for later analysis.Flow-mediated dilatation (FMD) was slightly lower in DM than C, 8.1 +/- 4.3% vs. 10.3 +/- 4.9% (p<0.05), and nitrate-mediated dilatation (NMD) was markedly lower, 21.7 +/- 6.6% vs. 31.4 +/- 5.7% (p<0.001). Lumen diameter, intima-media thickness and distensibility were similar in DM and C. Insulin-like growth factor (IGF-1) was lower in DM than C, 231 +/- 65 vs. 349 +/- 68 ng/ml (p<0.001). Glycosylated haemoglobin (HbA(1C)) and matrix metalloproteinase (MMP-9) were independent predictors of the reduced NMD in the DM.Brachial artery responsiveness to an exogenous donor of nitric oxide (NO) was markedly reduced in type 1 diabetic women despite only limited reduction in endothelium-dependent dilatation. The negative association between NMD and HbA(1C) suggests that long-term hyperglycaemia impairs vascular smooth muscle cell function in DM.
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| 20. |
- Blomgren, J, et al.
(author)
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Non-physiological levels of circulating cortisol in growth hormone-treated hypopituitary adults after conventional cortisone substitution
- 2004
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In: Scandinavian Journal of Clinical and Laboratory Investigation. - : Informa UK Limited. - 0036-5513 .- 1502-7686. ; 64:2, s. 132-139
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Journal article (peer-reviewed)abstract
- Objective: To assess the usefulness of measuring plasma cortisol profiles in growth hormone-treated hypopituitary adults and to compare these with cortisol levels in healthy controls. Methods: Eleven ACTH-deficient adult patients received 12.5 mg cortisone-acetate orally at 16.00 h and 25 mg at 07.00 h. The patients arrived in the ward at 12.00 h. After tablet intake at 16.00 h, samples for serum cortisol were taken at hourly intervals for the next 24 h, except between 07.00 and 12.00 h when samples were drawn every half hour, 24-h urinary free cortisol (24-h-UFC) excretion was collected simultaneously. For comparison, 8 healthy controls were investigated. Results: The patients had circulating cortisol levels with very low plasma cortisol at 07.00 h before their morning dose of cortisone acetate. At the same time period, controls had their highest plasma cortisol levels. After tablet intake the patients had a rapid initial absorption of cortisol, but a marked variability in the morning peak levels (Cmax), and the Cmax was in general higher and occurred 90 min later than the Cmax in the controls. The 24-h-UFC excretion and 24-h area under the curve (24-h-AUC) did not differ between patients and controls. The female patients had higher 24-h-AUC for plasma cortisol (p=0.032) and tended to have higher plasma cortisol peaks in the morning, but had levels of 24-h-UFC similar to those of the male patients. Conclusions: Conventional cortisone substitution with a twice-daily replacement regimen in hypopituitary adults results in abnormal circulating cortisol profiles with low or non-measurable morning values and variable individual peaks. This suggests that the present dosing schemes have to be improved and that cortisone substitution should be individualized.
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| 21. |
- Bojestig, M, et al.
(author)
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The renin-angiotensin-aldosterone system is suppressed in adults with Type 1 diabetes
- 2000
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In: jraas. Journal of the renin-angiotensin-aldosterone system. - 1470-3203 .- 1752-8976. ; 1:4, s. 353-356
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Journal article (peer-reviewed)abstract
- Poor glycaemic control and high blood pressure are two important risk factors for the development of retinopathy and nephropathy in Type 1 diabetes. The renin-angiotensin-aldosterone system (RAAS) may be involved in this process, since treatment with angiotensin-converting enzyme (ACE) inhibitors postpones the development of these complications. We investigated whether plasma renin activity (PRA), plasma angiotensin II (Ang II) and atrial natriuretic peptide (ANP) differed in Type 1 diabetic patients compared with healthy controls. We recruited 80 patients with Type 1 diabetes of more than 10 years' duration and 75 age-matched controls. We found that PRA and Ang II concentrations were significantly lower in patients than in the controls. The levels of ANP, on the other hand, were higher in patients than in controls. PRA correlated negatively to the mean value of HbA1c during the previous five years. PRA and Ang II were significantly lower in patients with mean HbA1c. >8.4% compared with those with mean HbA1c 7.2%. In summary, we found patients with Type 1 diabetes to have RAAS suppression and increased ANP levels, suggesting a state of fluid retention.
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| 22. |
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| 23. |
- Borg, Carola, 1973-
(author)
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Utbildning för hållbar utveckling ur ett lärarperspektiv : Ämnesbundna skillnader i gymnasieskolan
- 2011
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Licentiate thesis (other academic/artistic)abstract
- This thesis investigates how teachers from different disciplines understand and implement education for sustainable development in their teaching. A nationwide questionnaire study was conducted with 3229 upper secondary school teachers representing 224 schools in Sweden. The concept of sustainable development is complex and research has shown that teachers exhibit uncertainties in their understanding of it, and that the way they conceptualize sustainable development can have consequences for how they incorporate it into their teaching. Previous research has emphasized that Education for Sustainable Development (ESD) should promote interdisciplinary and holistic learning rather than traditional subject-based learning. This is in accordance with the Swedish curriculum, which emphasizes that all teachers in all subjects should integrate education for sustainable development. The teachers in the study were grouped into four disciplines; science-, social science-, language-, and vocational/esthetical-practical teachers. The results showed that there were many subject-bound barriers to successful implementation of ESD. Teachers were influenced by their subject tradition in: 1) how they understand sustainable development, 2) which teaching methods they use, 3) which barriers they experience, and 4) which teaching tradition they work within. Because of these differences it is important to adjust any further training of teachers according to their discipline. This study highlights the need for improved teacher education and further training of in-service teachers; more than 70% of the teachers stated that they need such training. It also highlights the issue how strong subject-bound traditions make it difficult to implement general goals of the curricula such as sustainable development.
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| 24. |
- Borg, Henrik, et al.
(author)
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Evaluation of the new ADA and WHO criteria for classification of diabetes mellitus in young adult people (15-34 yrs) in the Diabetes Incidence Study in Sweden (DISS)
- 2003
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In: Diabetologia. - : Springer Science and Business Media LLC. - 0012-186X .- 1432-0428. ; 46:2, s. 173-181
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Journal article (peer-reviewed)abstract
- Aims/hypothesis. We aimed to evaluate how an aetiology-based classification, as recommended in the ADA and WHO guidelines for classification of diabetes mellitus, matches clinical judgement in the Diabetes Incidence Study in Sweden (DISS), a study covering incident cases of diabetic patients aged 15 to 34 years. Methods. During a 1-year period (1998), blood samples were taken at diagnosis and 4 months (median) thereafter. Patients were classified according to clinical judgement by the reporting physicians and assessments of islet antibodies (ICA, GADA, and IA-2A) and plasma C-peptide. Results. In 1998, 422 patients were registered in DISS. Among the 313 patients participating in the follow-up, most with clinical Type 1 diabetes (185/218, 85%, 95% CI 79-89%) were islet antibody positive (ab+) at diagnosis. In addition, 14 out of 58 (24%, 14-37%) with clinical Type 2 diabetes and 21 out of 37 (57%, 40-73%) with unclassifiable diabetes were antibody positive at diagnosis. Further to this, 4 out of 33 (12%, 3-28%) were antibody negative with clinical Type 1 diabetes and 4 out of 44 (9%, 3-22%) with Type 2 had converted to antibody positive at follow-up. Among those who were constantly antibody negative, 10 out of 29 (34%, 18-54%) with clinical Type 1 and 1 out of 16 (6%, 0-30%) with unclassifiable diabetes had fasting plasma C-peptide concentrations below the normal range (<0.25 nmol/l) at follow-up. Conclusion/interpretation. Most young adults with clinical Type 1 diabetes (199/218, 91%) had objective Type 1 (ab+ at diagnosis/follow-up and/or low fasting plasma C-peptide concentrations at follow-up), as did one third (18/58, 31%) with clinical Type 2 diabetes and more than half (22/37, 59%) with unclassifiable diabetes. About 10% of those who were antibody negative converted to antibody positive. Our study underlines that a classification considering aetiology is superior to clinical judgement.
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| 25. |
- Bäck, Karolina, et al.
(author)
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Changes in insulin and IGF-I receptor expression during differentiation of human preadipocytes
- 2009
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In: Growth Hormone & IGF Research. - : Elsevier BV. - 1096-6374 .- 1532-2238. ; 19:2, s. 101-111
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Journal article (peer-reviewed)abstract
- Mature adipocytes originate from fibroblast-like precursor cells, preadipocytes, which differentiate to obtain the characteristics of adipocytes. Our aim was to investigate how differentiation of human preadipocytes affects the distribution of insulin receptors (IR) and IGF-I receptors (IGF-IR) and other cell characteristics. Preadipocytes were differentiated using indomethacine, dexamethasone, isobutyl-methylxantine (IBMX) and high concentration of insulin. Gene expression was quantified by real-time RT-PCT in preadipocytes (PA), differentiated preadipocytes (dPA) and mature adipocytes (mAD). The amount of expressed receptor protein was analyzed using receptor specific ELISAs and Western blot. We also studied DNA synthesis with radiolabeled thymidine incorporation and glucose accumulation with radiolabeled glucose. Differentiation of PA increased gene expression of IR but not IGF-IR, GLUT4, growth hormone receptor (GHR) and adiponectin appeared or increased. In PA and dPA only IR-A was expressed whereas also IR-B was detected in mAD. By Western blot and ELISA, IR and IGF-IR was phosphorylated by their own ligant at 1 nM and in dPA the acitivation of both receptors was stimulated by IGF-I, but not insulin, at 1 nM. Accumulation of glucose in PA was increased by insulin at 10 nM and by IGF-I at 1 nM and 10 nM. DNA synthesis was increased by insulin and IGF-I at 10 nM. In conclusion, both IR and IGF-IR are present in human preadipocytes and adipocytes. Differentiation is characterized by an increased IR/IGF-IR ratio.
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