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- Andersson, Christer, 1945-, et al.
(författare)
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Renal symtomatology in patients with acute intermitent porphyria
- 2000
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Ingår i: Journal of Internal Medicine. - : Wiley. - 0954-6820 .- 1365-2796. ; 248, s. 319-325
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Tidskriftsartikel (refereegranskat)abstract
- Objective: Can renal insufficiency in subjects with acute intermittent porphyria (AIP) be due solely to AIP?Design: A population-based study.Subjects: Subjects with AIP ≥ 18 years of age (n = 386) in the four most northerly counties of Sweden.Interventions: Screening with creatinine clearance at 24 h. Patients below the lower reference level underwent a repeat clearance test and, if still low, also chromEDTA clearance.Results: 286 (74%) subjects performed the creatinine clearance test and in 57 clearance was low; the second clearance proved normal in 23 who were then excluded. Eighteen subjects with other possible medical reasons for renal insufficiency, ethical reasons or refusing further examinations were also excluded. The 16 remaining subjects with no explanation for their renal insufficiency other than AIP were then studied in detail. All 14 women, mean age 52 years, and two uraemic men, 58 and 67 years, had manifest AIP. Twelve patients had hypertension (HT) and four were normotensive in spite of renal insufficiency. Histological findings of renal biopsies revealed diffuse glomerulosclerotic and interstitial changes with additional ischaemic lesions.Conclusion: Protracted vasospasm in attacks of AIP may be a cause of renal lesions. This is discussed.
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- Andersson, Christer, 1945-, et al.
(författare)
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The epideimiology of hepatocellular carcinoma in patients with acute intermittent porphyria
- 1996
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Ingår i: Journal of Internal Medicine. - : Wiley. - 0954-6820 .- 1365-2796. ; 240:4, s. 195-201
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Tidskriftsartikel (refereegranskat)abstract
- Objective. To describe the epidemiology, pathogenesis and clinical features of hepatocellular carcinoma (HCC) in patients with acute intermittent porphyria (AIP). Design. A retrospective population-based mortality study. Subjects. All inhabitants who died between 1978–1990 (2122) including 33 with AIP, in two municipalities in northern Sweden with a high prevalence of AIP. Interventions. Death certificates and hospital records were examined. Histological re-examination of paraffin-embedded specimens from patients with HCC was performed and hepatitis B virus content analysed. Results. HCC was found in 27% of patients with AIP versus 0.2% of the deceased non-AIP subjects, P< 0.0001. HCC was more common in women (men:women 1:2) and in manifest AIP (manifest: latent 2:1). Liver cirrhosis was more common in AIP patients (12%), especially in women, compared with controls (0.5%), P<0.0001. Conclusions. AIP patients seem to have an increased risk of developing HCC. This tumour is more common in patients with manifest AIP and in women, a reversal of the usually reported gender ratio for HCC. No cause for developing HCC other than AIP was found. The pathogenesis may be explained by abnormalities in porphyrin metabolism and by intrinsic production of mutagenic substances, resulting in a condition of systemic overload of oxidative stress, enhancing mutation rate and liver cell injury. Liver cirrhosis appears to be more common in AIP patients and may be a preliminary stage to HCC. All AIP gene carriers aged 55 should be screened for HCC.
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- 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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- Andersson, Erik, et al.
(författare)
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Reconnecting Cities to the Biosphere : Stewardship of Green Infrastructure and Urban Ecosystem Services
- 2014
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Ingår i: Ambio. - : Springer. - 0044-7447 .- 1654-7209. ; 43:4, s. 445-453
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Tidskriftsartikel (refereegranskat)abstract
- Within-city green infrastructure can offer opportunities and new contexts for people to become stewards of ecosystem services. We analyze cities as social-ecological systems, synthesize the literature, and provide examples from more than 15 years of research in the Stockholm urban region, Sweden. The social-ecological approach spans from investigating ecosystem properties to the social frameworks and personal values that drive and shape human interactions with nature. Key findings demonstrate that urban ecosystem services are generated by social-ecological systems and that local stewards are critically important. However, land-use planning and management seldom account for their role in the generation of urban ecosystem services. While the small scale patchwork of land uses in cities stimulates intense interactions across borders much focus is still on individual patches. The results highlight the importance and complexity of stewardship of urban biodiversity and ecosystem services and of the planning and governance of urban green infrastructure.
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