| 1. |
- Araujo, I. M., et al.
(författare)
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Changes in calcium dynamics following the reversal of the sodium-calcium exchanger have a key role in AMPA receptor-mediated neurodegeneration via calpain activation in hippocampal neurons
- 2007
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Ingår i: Cell Death and Differentiation. - : Springer Science and Business Media LLC. - 1350-9047 .- 1476-5403. ; 14:9, s. 1635-1646
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Tidskriftsartikel (refereegranskat)abstract
- Proteolytic cleavage of the Na+/Ca2+ exchanger (NCX) by calpains impairs calcium homeostasis, leading to a delayed calcium overload and excitotoxic cell death. However, it is not known whether reversal of the exchanger contributes to activate calpains and trigger neuronal death. We investigated the role of the reversal of the NCX in Ca2+ dynamics, calpain activation and cell viability, in alpha-amino-3-hydroxy-5-methylisoxazole-4-propionate (AMPA) receptor-stimulated hippocampal neurons. Selective overactivation of AMPA receptors caused the reversal of the NCX, which accounted for approximately 30% of the rise in intracellular free calcium concentration ([Ca2+](i)). The NCX reverse-mode inhibitor, 2-[2-[4-(4-nitrobenzyloxy) phenyl]ethyl] isothiourea (KB-R7943), partially inhibited the initial increase in [Ca2+](i), and prevented a delayed increase in [Ca2+](i). In parallel, overactivation of AMPA receptors strongly activated calpains and led to the proteolysis of NCX3. KB-R7943 prevented calpain activation, cleavage of NCX3 and was neuroprotective. Silencing of NCX3 reduced Ca2+ uptake, calpain activation and was neuroprotective. Our data show for the first time that NCX reversal is an early event following AMPA receptor stimulation and is linked to the activation of calpains. Since calpain activation subsequently inactivates NCX, causing a secondary Ca2+ entry, NCX may be viewed as a new suicide substrate operating in a Ca2+-dependent loop that triggers cell death and as a target for neuroprotection.
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| 2. |
- Merletti, F, et al.
(författare)
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Occupational factors and risk of adult bone sarcomas: A multicentric case-control study in Europe
- 2006
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Ingår i: International Journal of Cancer. - : Wiley. - 0020-7136. ; 118:3, s. 721-727
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Tidskriftsartikel (refereegranskat)abstract
- We investigated the association between occupational factors and risk of bone sarcoma, a rare tumor with a largely unknown aetiology. A multicentric case-control study was conducted in 7 European countries in 1995-97. Ninety-six cases aged 35-69 years with a centrally reviewed diagnosis of bone sarcoma (68 chondrosarcomas and 28 osteosarcomas) were compared to 2,632 population (68%) or colon cancer (32%) controls. Subjects were interviewed to obtain information on occupational, medical and reproductive history, smoking and alcohol consumption and selected exposures including use of pesticides. Response proportions were 90% among cases and 66% among controls. Odds ratios (OR) and 95% confidence intervals (CI) were estimated for selected categories of job titles and branches of industry and for use of pesticides. We found an increased OR for bone sarcoma among blacksmiths, toolmakers, machine-tool operators (OR = 2.14, 95% CI 1.08-4.26), woodworkers (OR = 2.68, 95% CI 1.36-5.29) and construction workers (OR = 1.62, 95% CI 0.92-2.87). Ever users of pesticide had an OR of 2.33 (95% CI 1.31-4.13), with similar risks for exposure to insecticides and exposure to herbicides. Neither duration of employment in any of the analyzed occupational categories nor duration of use of pesticides showed an increasing trend in the risk of bone sarcoma. ORs of bone sarcoma were 1.03 (95% CI 0.23-4.57), 3.13 (95% CI 1.26-7.76) and 1.44 (95% CI 0.43-4.85) for the first, second and third fertile of days of use of pesticides. Our study suggests that novel and previously reported (woodworking) occupational factors play a role in the aetiology of bone sarcomas. (c) 2005 Wiley-Liss, Inc.
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| 3. |
- Tajkumar, T, et al.
(författare)
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Cervical carcinoma and sexual behavior: collaborative reanalysis of individual data on 15,461 women with cervical carcinoma and 29,164 women without cervical carcinoma from 21 epidemiological studies
- 2009
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Ingår i: Cancer Epidemiology Biomarkers & Prevention. - 1538-7755. ; 18:4, s. 1060-1069
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Tidskriftsartikel (refereegranskat)abstract
- High-risk human papillomavirus (HPV) types cause most cervical carcinomas and are sexually transmitted. Sexual behavior therefore affects HPV exposure and its cancer sequelae. The International Collaboration of Epidemiological Studies of Cervical Cancer has combined data on lifetime number of sexual partners and age at first sexual intercourse from 21 studies, or groups of studies, including 10,773 women with invasive cervical carcinoma, 4,688 women with cervical intraepithelial neoplasia grade 3 (CIN3)/carcinoma in situ, and 29,164 women without cervical carcinoma. Relative risks for invasive cancer and CIN3 were estimated by conditional logistic regression. Risk of invasive cervical carcinoma increased with lifetime number of sexual partners (P for linear trend <0.001). The relative risk for > or =6 versus 1 partner, conditioned on age, study, and age at first intercourse, was 2.27 [95% confidence interval (95% CI), 1.98-2.61] and increased to 2.78 (95% CI, 2.22-3.47) after additional conditioning on reproductive factors. The risk of invasive cervical carcinoma increased with earlier age at first intercourse (P for linear trend <0.001). The relative risk for age at first intercourse < or =14 versus > or =25 years, conditioned on age, study, and lifetime number of sexual partners was 3.52 (95% CI, 3.04-4.08), which decreased to 2.05 (95% CI, 1.54-2.73) after additional conditioning on reproductive factors. CIN3/carcinoma in situ showed a similar association with lifetime number of sexual partners; however, the association with age at first intercourse was weaker than for invasive carcinoma. Results should be interpreted with caution given the strong correlation between sexual and reproductive factors and the limited information on HPV status.
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| 4. |
- Erdtman, Edvin, et al.
(författare)
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Modelling the behavior of 5-aminolevulinic acid and its alkyl esters in a lipid bilayer
- 2008
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Ingår i: Chemical Physics Letters. - Amsterdam : North-Holland Publishing Co. - 0009-2614 .- 1873-4448. ; 463:1-3, s. 178-182
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Tidskriftsartikel (refereegranskat)abstract
- 5-Aminolevulinic acid (5ALA) and ester derivates thereof are used as prodrugs in photodynamic therapy (PDT). The behavior of 5ALA and three esters of 5ALA in a DPPC lipid bilayer is investigated. In particular, the methyl ester displays a very different free energy profile, where the highest barrier is located in the region with highest lipid density, while the others have their peak in the middle of the membrane, and also displays a considerably lower permeability coefficient than neutral 5ALA and the ethyl ester. The zwitterion of 5ALA has the highest permeability constant, but a significant free energy minimum in the polar head-group region renders an accumulation in this region.
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| 5. |
- Dos Santos, Nancy, et al.
(författare)
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Influence of poly(ethylene glycol) grafting density and polymer length on liposomes : Relating plasma circulation lifetimes to protein binding
- 2007
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Ingår i: Biochimica et Biophysica Acta - Biomembranes. - : Elsevier BV. - 0005-2736 .- 1879-2642. ; 1768:6, s. 1367-1377
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Tidskriftsartikel (refereegranskat)abstract
- The incorporation of poly(ethylene glycol) (PEG)-conjugated lipids in lipid-based carriers substantially prolongs the circulation lifetime of liposomes. However, the mechanism(s) by which PEG-lipids achieve this have not been fully elucidated. It is believed that PEG-lipids mediate steric stabilization, ultimately reducing surface-surface interactions including the aggregation of liposomes and/or adsorption of plasma proteins. The purpose of the studies described here was to compare the effects of PEG-lipid incorporation in liposomes on protein binding, liposome-liposome aggregation and pharmacokinetics in mice. Cholesterol-free liposomes were chosen because of their increasing importance as liposomal delivery systems and their marked sensitivity to protein binding and aggregation. Specifically, liposomes containing various molecular weight PEG-lipids at a variety of molar proportions were analyzed for in vivo clearance, aggregation state (size exclusion chromatography, quasi-elastic light scattering, cryo-transmission and freeze fracture electron microscopy) as well as in vitro and in vivo protein binding. The results indicated that as little as 0.5 mol% of 1,2-distearoyl-sn-glycero-3-phosphatidylethanolamine (DSPE) modified with PEG having a mean molecular weight of 2000 (DSPE-PEG(2000)) substantially increased plasma circulation longevity of liposomes prepared of 1,2-distearoyl-sn-glycero-3-phosphatidylcholine (DSPC). Optimal plasma circulation lifetimes could be achieved with 2 mol% DSPE-PEG(2000). At this proportion of DSPE-PEG(2000), the aggregation of DSPC-based liposomes was completely precluded. However, the total protein adsorption and the protein profile was not influenced by the level of DSPE-PEG(2000) in the membrane. These studies suggest that PEG-lipids reduce the in vivo clearance of cholesterol-free liposomal formulations primarily by inhibition of surface interactions, particularly liposome-liposome aggregation.
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| 6. |
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| 7. |
- Pouladi, Mahmoud A, et al.
(författare)
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Prevention of depressive behaviour in the YAC128 mouse model of Huntington disease by mutation at residue 586 of huntingtin.
- 2009
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Ingår i: Brain. - : Oxford University Press (OUP). - 1460-2156 .- 0006-8950. ; 132, s. 919-932
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Tidskriftsartikel (refereegranskat)abstract
- Huntington disease is a neurodegenerative disorder caused by an expanded CAG repeat in the Huntington disease gene. The symptomatic phase of the disease is defined by the onset of motor symptoms. However, psychiatric disturbances, including depression, are common features of Huntington disease and recent studies indicate that depression can occur long before the manifestation of motor symptoms. The aetiology of depression in Huntington disease is not fully understood and psychosocial factors such as the knowledge of carrying a mutation for an incurable disease or adverse social circumstances may contribute to its presentation. Due to the difficulties in discriminating between social and biological factors as contributors to depression in clinical Huntington disease, we chose to assess whether a model for Huntington disease not subject to environmental stressors, namely the YAC mouse model of Huntington disease, displays a depressive phenotype. Indeed, the YAC transgenic mice recapitulate the early depressive phenotype of Huntington disease as assessed by the Porsolt forced swim test as well as the sucrose intake test as a measure of anhedonia. The YAC model mirrors clinical Huntington disease in that there were no effects of CAG repeat length or disease duration on the depressive phenotype. The depressive phenotype was completely rescued in YAC transgenic animals expressing a variant of mutant huntingtin that is resistant to cleavage at amino acid 586 suggesting that therapies aimed towards inhibition of huntingtin cleavage are also likely to have beneficial effects on this aspect of the disease. In conclusion, our study provides strong support for a primary neurobiological basis for depression in Huntington disease.
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| 8. |
- Rajkumar, T, et al.
(författare)
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Carcinoma of the cervix and tobacco smoking: Collaborative reanalysis of individual data on 13,541 women with carcinoma of the cervix and 23,017 women without carcinoma of the cervix from 23 epidemiological studies - International collaboration of epidemiological studies of cervical cancer
- 2006
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Ingår i: International Journal of Cancer. - : Wiley. - 0020-7136. ; 118:6, s. 1481-1495
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Tidskriftsartikel (refereegranskat)abstract
- Tobacco smoking has been classified as a cause of cervical cancer, but the effect of different patterns of smoking on risk is unclear. The International Collaboration of Epidemiological Studies of Cervical Cancer has brought together and combined individual data on 13,541 women with and 23,017 women without cervical carcinoma, from 23 epidemiological studies. Relative risks (RRs) and 95% confidence intervals (CIs) of carcinoma of the cervix in relation to tobacco smoking were calculated with stratification by study, age, sexual partners, age at first intercourse, oral contraceptive use and parity. Current smokers had a significantly increased risk of squamous cell carcinoma of the cervix compared to never smokers (RR = 1.60 (95% CI: 1.48-1.73), p < 0.001). There was increased risk for past smokers also, though to a lesser extent (RR = 1.12 (1.01-1.25)), and there was no clear trend with time since stopping smoking (p-trend = 0.6). There was no association between smoking and adenocarcinoma of the cervix (RR = 0.89 (0.74-1.06) and 0.89 (0.72-1.10) for current and past smokers respectively), and the differences between the RRs for smoking and squamous cell and adenocarcinoma were statistically significant (current smoking p < 0.001 and past smoking p = 0.01). In current smokers, the RR of squamous cell carcinoma increased with increasing number of cigarettes smoked per day and also with younger age at starting smoking (p < 0.001 for each trend), but not with duration of smoking (p-trend = 0.3). Eight of the studies had tested women for cervical HPV-DNA, and in analyses restricted to women who tested positive, there was a significantly increased risk in current compared to never smokers for squamous cell carcinoma (RR = 1.95 (1.43-2.65)), but not for adenocarcinoma (RR = 1.06 (0.14-7.96)). In summary, smokers are at an increased risk of squamous cell but not of adenocarcinoma of the cervix. The risk of squamous cell carcinoma increases in current smokers with the number of cigarettes smoked per day and with younger age at starting smoking.
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