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| 2. |
- Agardh, Elisabet, et al.
(författare)
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Severe retinopathy in type 1 diabetic patients is not related to the level of plasma homocysteine
- 2000
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Ingår i: Scandinavian Journal of Clinical & Laboratory Investigation. - : Informa UK Limited. - 1502-7686 .- 0036-5513. ; 60:3, s. 169-174
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Tidskriftsartikel (refereegranskat)abstract
- The vascular-injuring amino acid homocysteine was previously shown to be increased in plasma in type 1 diabetic patients with clinical signs of nephropathy. Previous studies have also shown an inconsistent relationship between the development of diabetic nephropathy and retinopathy, indicating different pathogenetic mechanisms. In this study, plasma homocysteine was measured in 25 type 1 diabetic patients with a well-characterized form of severe retinopathy. Furthermore, a group of 24 type 1 diabetic patients with similar age at onset of diabetes and diabetes duration with no or minimal background retinopathy were investigated, in order to determine whether plasma homocysteine levels are different from those in patients with severe retinopathy. Patients with severe retinopathy did not have higher plasma levels of homocysteine (13.9 micromol/L; 5.9-30.7, median and range) than those without retinopathy (10.4 micromol/L; 5.7-18.9). Within the group of patients with severe retinopathy, increased homocysteine levels were confined to the patients (19.9 micromol/L; 10.0-30.7, n=9) with serum creatinine levels > 100 micromol/L, compared to those patients (9.6; 5.9-14.3 micromol/L, n=15) with a serum creatinine below 100 micromol/L. None of the patients without or with minimal background retinopathy had serum creatinine levels > 100 micromol/L. We conclude that diabetic retinopathy is not associated with increased plasma homocysteine levels, but plasma homocysteine accumulates, probably owing to reduced glomerular filtration, in diabetic patients with signs of nephropathy. In these patients, the promoting effect of nephropathy on the development of retinopathy does not seem to be mediated through homocysteine.
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| 3. |
- Ahola, T, et al.
(författare)
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Thiol metabolism in preterm infants during the first week of life
- 2004
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Ingår i: Scandinavian Journal of Clinical & Laboratory Investigation. - : Informa UK Limited. - 1502-7686 .- 0036-5513. ; 64:7, s. 649-658
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Tidskriftsartikel (refereegranskat)abstract
- Background: Oxidative stress is implicated in the pathogenesis of several complications of prematurity. The glutathione cycle is one of the most important intracellular antioxidant systems. The synthesis of glutathione may not be adequate in preterm neonates because of the low levels of cysteine available. The aim of this study was to evaluate cysteine and glutathione metabolism during the first week of life in preterm infants. Methods: Plasma and erythrocyte thiol concentrations were measured in 78 preterm infants with a birthweight of 500 1500 g, and erythrocyte glutamate-cysteine ligase (GCL), glutathione peroxidase (GPx), glutathione reductase (GR), glutathione S-transferases (GST) and glucose 6-phosphatedehydrogenase (G6PDH) in 26 infants with a birthweight of 1000 - 1500 g. Results: The mean (SD) plasma glutathione concentration increased from day 0 to day 1 (14.9 (7.1) vs. 27.7 (11.9) mumol/L, p<0.001), and then decreased. The plasma cysteine concentration changed in the opposite direction ( 172 (59) vs. 129 (42) μmol/L, p<0.01). In infants with respiratory distress syndrome (RDS) the mean plasma glutathione concentration, but not cysteine, was lower on day 0 compared with infants without RDS (11.7 (5.2) vs. 21.4 (5.6) mumol/L, p<0.01). Erythrocyte glutathione concentration decreased during the first week of life, whereas erythrocyte cysteine concentration increased significantly from day 3 to day 7 (p<0.01). Erythrocyte cysteine and glutathione concentrations had a positive correlation. The GCL and GR activities did not change, but GST and G6PDH activities decreased during the first week (p<0.01). GPx activity decreased until day 3 (p<0.01) and was higher on day 0 and day 1 in infants with RDS. Conclusions: Very low birthweight infants have an initial increase in plasma glutathione and initial decrease in plasma cysteine level during the first week of life, and also a positive correlation between erythrocyte cysteine and glutathione levels.
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| 4. |
- Almquist, Martin, et al.
(författare)
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Reproductive history, lifestyle factors and season as determinants for serum calcium concentrations in women.
- 2008
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Ingår i: Scandinavian Journal of Clinical & Laboratory Investigation. - : Informa UK Limited. - 1502-7686 .- 0036-5513. ; 68, s. 777-785
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Tidskriftsartikel (refereegranskat)abstract
- Objective. Serum calcium concentrations have been associated with the risk of malignant disease, especially breast cancer. Thus, determinants of serum calcium concentrations, with special regard to risk factors of breast cancer, are of great interest. Material and methods. Previous studies have either been small or they have not focused on reproductive factors. The present study examined serum calcium concentrations in relation to reproductive history, selected lifestyle factors and screening season in a large population-based cohort study comprising 8,114 women. ANOVA followed by the Bonferroni t-test were used for comparison of means, and logistic regression and multiple regression analysis were used to test associations. Results. Serum calcium concentrations were lower in hormone replacement therapy users versus non-users (2.321 mmol/L versus 2.364; p<0.001) and in users of oral contraceptives versus non-users (2.304 versus 2.348; p<0.001). They were higher in peri-/postmenopausal versus premenopausal women (2.357 versus 2.319; p<0.001). Overweight and obese women had higher mean calcium concentrations (2.350 and 2.355) than women with body mass index between 20 and 25 (2.342; p<0.001). Serum calcium concentrations were higher in spring and autumn than in winter (2.352 and 2.353 versus 2.343; p = 0.002). Both younger (40-45 years) (2.334; p = 0.001) and older age groups (>55 years) (2.363; p<0.001) had higher mean calcium concentrations compared to those of women aged 45-50 years (2.320), even when adjusting for menopausal status, suggesting that age has an independent influence on calcium concentrations. Conclusions. It is concluded that reproductive factors such as menopausal status, use of oral contraceptives or hormone-replacement therapy, and age, BMI and season are associated with serum calcium concentrations.
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| 5. |
- Almqvist, E G, et al.
(författare)
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Hypothalamic-pituitary-adrenal response to different tests in type 1 diabetes mellitus
- 2001
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Ingår i: Scandinavian Journal of Clinical & Laboratory Investigation. - : Informa UK Limited. - 1502-7686 .- 0036-5513. ; 61:7, s. 557-565
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To determine whether different tests of the adrenocorticotropic hormone (ACTH) reserve are influenced by diabetic state and metabolic control in newly diagnosed type 1 diabetic patients. DESIGN AND METHODS: We evaluated the ACTH reserve in 10 patients with uncomplicated type 1 diabetes during periods of poor and improved metabolic control and in 10 healthy subjects. The ACTH-cortisol secretion was assessed by a diurnal profile, an intravenous corticotropin-releasing hormone (CRH) test and an insulin tolerance test (ITT). RESULTS: The diurnal profiles were similar in all groups. CRH resulted in a diminished ACTH response during poor compared with improved metabolic control (mean+/-SD) (AUC 4950+/-4227 vs. 5847+/-3788 ng/L min, p<0.05). The response in the diabetic patients during improved metabolic control was of the same magnitude as in the control subjects (5934+/-1778 ng/L x min). ITT elicited a similar ACTH and cortisol response in the diabetic patients during poor and improved metabolic control as in the healthy control subjects. CONCLUSIONS: The ITT was uninfluenced by diabetic state and metabolic control and should therefore be considered the method of choice in evaluation of the ACTH reserve in patients with type 1 diabetes.
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| 6. |
- Andersson, Christer, 1945-, et al.
(författare)
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The W198X and R173W mutations in the porphobilinogen deaminase gene in acute intermittent porphyria have higher clinical penetrance than R167 : a populations-based study
- 2000
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Ingår i: Scandinavian Journal of Clinical and Laboratory Investigation. - : Informa UK Limited. - 0036-5513 .- 1502-7686. ; 60:7, s. 643-648
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Tidskriftsartikel (refereegranskat)abstract
- The biosynthesis of porphyrins is one of the most conserved parthways known, about the same sequence of reactions taking place in all species. By associating different metals, porphyrins give rise to the “pigments of life”: chlorophyll, haem and cobalamin. The unique tetrapyrrolic structure enables it to function in an array of reactions as a single electron carrier and as a catalyst for redox reactions. In this capacity, it constitutes the prosthetic group of enzymes participating in cellular respiration, in conversion reactions involving steroids and lipophilic xenobiotics, in protective mechanisms directed against oxidative stress and in pathways providing central messenger molecules. The formation of haem is accomplished by a sequence of eight dedicated enzymes encoded by different genes, some being active in ubiquitous as well as in erythroid isoforms. Large differences between the participating enzymes with regard to catalytic power, with low capacity steps positioned early in the catalytic chain, constitute a bar against substrate overloading of enzymes processing porphyrins, thus preventing accumulation in the body of these phototoxic compounds under physiological conditions. Most of the haem in the body is produced by the liver and bone marrow, but the mechanisms applied for the control of the synthesis differ between the two organs. The extremely potent hemeprotein enzymes formed in the liver are rapidly turned over in response to current metabolic needs. They have half-lives in the order of minutes or hours and are restored by fast-acting mechanisms for the de novo synthesis, when needed. Uninterrupted and instant availability of the compound is secured by acute deinhibition of the initial enzyme of the synthetic chain, ubiquitous 5-aminolevulinate synthase (ALAS-1), in response to drain of the free cellular haem pool caused by prevailing demands for hemeproteins or by increased catabolism of the compound. In contrast, in the erythroid progenitor cell the haem synthetic machinery is designed for uninterrupted production of huge amounts of haem for combination with globin chains to form hemoglobin at a steady rate. In the erythron the synthesis of the enzymes participating in the formation of haem is under control of erythropoietin, formed under hypoxic conditions. In the absence of iron, to be incorporated in the porphyrin formed in the last step of the synthesis, the mRNA of erythroid 5-aminolevulinate synthase (ALAS-2) is blocked by attachment of an iron-responsive element (IRE) binding cytosolic protein, and transcription of this key enzyme is inhibited. In humans, the genes for each of the haem synthetic enzymes may become the target of mutations that give rise to impaired cellular enzyme activity. Seven of the enzyme deficiencies are associated with accumulation of toxic intermediaries and with disease entities termed porphyrias. The acute porphyrias are characterized by attacks of neuropsychiatric symptoms, which may be due to a toxic surplus of the porphyrin presursor 5-aminolevulinic acid, or a consequence of a deficit of vital hemeproteins resulting from impaired synthesis of haem. In the cutaneous porphyrias, impairment of enzymatic steps where porphyrins are processed gives rise to solar hypersensitivity due to accumulation of phototoxic porphyrins in the skin. Early diagnosis, information to the patient regarding the nature of the illness and counselling aimed at avoidance of triggering factors are cornerstones in the handling of the porphyric diseases. Gene analysis is of incomparable diagnostic reliability in carrier detection, but biochemical methods must be applied in the important task of monitoring porphyric disease activity. In most forms of porphyria the gene carriers run the risk of development of associated diseases in liver or kidneys, a circumstance that prompts application of well-structured surveillance programs.
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| 9. |
- Arnadottir, Margret, et al.
(författare)
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Effects of short-term treatment with corticotropin on the serum apolipoprotein pattern
- 2001
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Ingår i: Scandinavian Journal of Clinical & Laboratory Investigation. - : Informa UK Limited. - 1502-7686 .- 0036-5513. ; 61:4, s. 301-306
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Tidskriftsartikel (refereegranskat)abstract
- Treatment with adrenocorticotrophic hormone (ACTH) has a well-documented cholesterol-lowering effect. Increased uptake of low-density lipoprotein (LDL) by HepG2 cells in response to incubation with ACTH has been demonstrated but the precise cholesterol-lowering mechanism has resisted elucidation. Since apolipoproteins are important determinants of lipoprotein metabolism, we sought to extend the knowledge of the effect of ACTH treatment on the serum apolipoprotein (apo) pattern. Twelve healthy individuals and 14 dyslipoproteinemic hemodialysis patients were recruited. The two groups responded similarly to ACTH1-24 at the dose of 1 mg daily for four days. In accordance with previous results, serum concentrations of total cholesterol decreased by 18% and 17%, LDL cholesterol by 25% and 30%, and apo B by 20% and 19%, respectively, while there were no significant changes in the serum concentrations of triglycerides, high-density lipoprotein cholesterol and apo AI. Novel findings were that the serum concentrations of total apo E increased by 48% and 31%, and apo B-associated apo E by 69% and 46%, respectively. Moreover, in the healthy individuals, the serum concentrations of apo CIII did not change in response to ACTH, whereas in the hemodialysis patients, those of apo CIII not associated with apo B increased significantly by 44%. Since apo E binds strongly to the LDL receptor, the present results suggest that the cholesterol-lowering effect of ACTH may be mediated by facilitated hepatic uptake of apo E-enriched apo B-containing lipoproteins. Thus, the findings stimulate further research.
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| 10. |
- Arvidson, Nils Gunnar, et al.
(författare)
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Short-term effects of the TNFalpha antagonist infliximab on the acute phase reaction and activities of daily life in patients with rheumatoid arthritis
- 2007
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Ingår i: Scandinavian Journal of Clinical and Laboratory Investigation. - : Informa UK Limited. - 0036-5513 .- 1502-7686. ; 67:3, s. 337-342
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Tidskriftsartikel (refereegranskat)abstract
- Objective. To investigate the short-term effects of the tumour necrosis factor alpha (TNFα) antagonist infliximab on the acute phase reaction and activities of daily life (ADL) in patients with rheumatoid arthritis (RA). Methods. Fourteen patients with active RA were treated with an intravenous infusion of 200 mg infliximab. The values of the erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), fibrinogen, granulocyte count, lymphocyte count, platelet count and a patient questionnaire score on ADL, the Health Assessment Questionnaire (HAQ), were obtained at baseline and on days 4 and 14. The significance levels and effect sizes (ESs) of the changes from baseline were calculated. Results. Changes by day 4: The ESs and significance levels were: CRP 1.7, p<0.005; lymphocyte count 1.4, p<0.005; fibrinogen 0.9, p<0.005; ESR 0.7, p<0.005; and HAQ 0.6, p<0.01. Changes by day 14: CRP 1.6, p<0.005; ESR 1.5, p<0.005; fibrinogen 1.3, p<0.005; lymphocyte count 1.0, p<0.005; granulocyte count 0.7, p<0.05; and HAQ 0.6, p<0.05. Conclusion. CRP, fibrinogen and ESR showed the largest ESs and were thus the most sensitive variables showing the early effect of infliximab in this study. The score on ADL (HAQ) showed less ES, but still significant short-term improvements.
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