| 1. |
- Broberg Palmgren, Karin, et al.
(författare)
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Influence of genetic factors on toluene diisocyanate-related symptoms: evidence from a cross-sectional study
- 2008
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Ingår i: Environmental Health. - 1476-069X. ; 7:15
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Tidskriftsartikel (refereegranskat)abstract
- Background: Toluene diisocyanate (TDI) is a highly reactive compound used in the production of, e. g., polyurethane foams and paints. TDI is known to cause respiratory symptoms and diseases. Because TDI causes symptoms in only a fraction of exposed workers, genetic factors may play a key role in disease susceptibility. Methods: Workers (N = 132) exposed to TDI and a non-exposed group ( N = 114) were analyzed for genotype (metabolising genes: CYP1A1*2A, CYP1A1*2B, GSTM1*O, GSTM3*B, GSTP1 1105V, GSTP1 A114V, GSTT1*O, MPO -463, NAT1*3, *4, *10, *11, *14, *15, NAT2*5, *6, *7, SULT1A1 R213H; immune-related genes: CCL5 -403, HLA-DQB1* 05, TNF-308, TNF-863) and symptoms of the eyes, upper and lower airways ( based on structured interviews). Results: For three polymorphisms: CYP1A1*2A, CYP1A1*2B, and TNF -308 there was a pattern consistent with interaction between genotype and TDI exposure status for the majority of symptoms investigated, although it did reach statistical significance only for some symptoms: among TDI-exposed workers, the CYP1A1 variant carriers had increased risk (CYP1A1*2A and eye symptoms: variant carriers OR 2.0 95% CI 0.68-6.1, p-value for interaction 0.048; CYP1A1*2B and wheeze: IV carriers OR = 12, 1.4-110, p-value for interaction 0.057). TDI-exposed individuals with TNF-308 A were protected against the majority of symptoms, but it did not reach statistical significance. In the non-exposed group, however, TNF -308 A carriers showed higher risk of the majority of symptoms ( eye symptoms: variant carriers OR = 2.8, 1.1-7.1, p-value for interaction 0.12; dry cough OR = 2.2, 0.69-7.2, p-value for interaction 0.036). Individuals with SULT1A1 213H had reduced risk both in the exposed and non-exposed groups. Other polymorphisms, showed associations to certain symptoms: among TDI-exposed, NAT1*10 carriers had a higher risk of eye symptoms and CCL5 -403 AG+AA as well as HLA-DQB1 *05 carriers displayed increased risk of symptoms of the lower airways. GSTM1, GSTM3 and GSTP1 only displayed effects on symptoms of the lower airways in the non-exposed group. Conclusion: Specific gene-TDI interactions for symptoms of the eyes and lower airways appear to exist. The results suggest different mechanisms for TDI- and non- TDI-related symptoms of the eyes and lower airways.
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| 2. |
- Broberg Palmgren, Karin, et al.
(författare)
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The GSTP1 Ile105 Val polymorphism modifies the metabolism of toluene di-isocyanate.
- 2010
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Ingår i: Pharmacogenetics & Genomics. - 1744-6872 .- 1744-6880. ; 20:2, s. 104-111
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Toluene di-isocyanate (TDI) is widely used in the production of polyurethane foams and paints. As TDI causes respiratory disease in only a fraction of exposed workers, genetic factors may play a key role in disease susceptibility. Polymorphisms in TDI metabolising genes may affect elimination kinetics, resulting in differences in body retention, and in its turn differences in adverse effects. OBJECTIVES: To analyze how genotype modifies the associations between (i) TDI in air (2,4-TDI and 2,6-TDI) and its metabolites toluene diamine (TDA; 2,4-TDA and 2,6-TDA) in hydrolyzed urine; and (ii) 2,4-TDA and 2,6-TDA in hydrolyzed plasma and 2,4-TDA and 2,6-TDA in urine. METHODS: Workers exposed to TDI were analyzed for 2,4-TDI and 2,6-TDI in air (N=70), 2,4-TDA and 2,6-TDA in hydrolyzed urine (N=124) and in plasma (N=128), and genotype: CYP1A1*2A, CYP1A1*2B, GSTA1-52, GSTM1O, GSTM3B, GSTP1 I105V, GSTP1 A114V, GSTT1O, MPO-463, NAT1*3, *4, *10, *11, *14, *15, NAT2*5, *6, *7, and SULT1A1 R213H. RESULTS: GSTP1 105 strongly modified the relationship between 2,4-TDA in plasma and in urine: ValVal carriers had about twice as steep regression slope than IleIle carriers. A similar pattern was found for 2,6-TDA. CYP1A1*2A, GSTM1, GSTP1, GSTT1, and MPO possibly influenced the relationship between TDA in plasma and urine. CONCLUSION: Our results show, for the first time, genetic modification on the human TDI metabolism. The findings suggest that GSTP1 genotype should be considered when evaluating biomarkers of TDI exposure in urine and plasma. Moreover, the results support earlier findings of GSTP1 105 Val as protective against TDI-related asthma.
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| 3. |
- Vikström, Anna C., et al.
(författare)
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Hemoglobin adducts as a measure of variations in exposure to acrylamide in food and comparison to questionnaire data
- 2012
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Ingår i: Food and Chemical Toxicology. - : Elsevier BV. - 0278-6915 .- 1873-6351. ; 50:7, s. 2531-2539
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Tidskriftsartikel (refereegranskat)abstract
- Measurement of haemoglobin (Hb) adducts from acrylamide (AA) and its metabolite glycidamide (GA) is a possibility to improve the exposure assessment in epidemiological studies of AA intake from food. This study aims to clarify the reliability of Hb-adduct measurement from individual single samples for exposure assessment of dietary AA intake. The intra-individual variations of AA- and GA-adduct levels measured in blood samples collected over 20 months from 13 non-smokers were up to 2-fold and 4-fold, respectively. The corresponding interindividual variations observed between 68 non-smokers, with large differences in AA intake, were 6-fold and 8-fold, respectively. The intra-individual variation of the GA-to-AA-adduct level ratio was up to 3-fold, compared to 11-fold between individuals (n = 68). From AA-adduct levels the average AA daily intake (n = 68) was calculated and compared to that estimated from dietary history methodology: 0.52 and 0.67 mu g/kg body weight and day, respectively. At an individual level the measures showed low association (Rs = 0.39). Conclusions: Dietary AA is the dominating source to measured AA-adduct levels and corresponding inter- and intra-individual variations in non-smokers. Measurements from single individual samples are useful for calculation of average M intake and its variation in a cohort, and for identification of individuals only from extreme intake groups.
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| 4. |
- Ahmadi, Ahmad, 1964-
(författare)
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Genetic predisposition and risk factors for neurodegenerative diseases with special emphasis on Parkinson's disease and solvent-induced chronic toxic encephalopathy
- 2004
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The inter-individual variability in biotransformation, may lead to differences in activation and detoxification of both endogenous and exogenous compounds. Polymorphism studies in such genes were applied for Parkinson's disease (PD) and Chronic toxic encephalopathy (CTE), two diseases influenced by both genetic and enviromnental factors.An elevated median age for the onset of PD was found among GS1M1 gene carriers compared to PD patients being GS1M1 null genotypes (68 years versus 57 years). No similar difference was found for GSTT1. mEPHX (113HH) isoform, which has been suggested as a low activity variant, is over represented in PD patients (OR=3.8, CI 95%, 1.2-11.8).Monoamine oxidases (MAO-A and -B) are important in the dopamine metabolism and in the detoxification of neurotoxins and genetic variants in these genes have earlier been assigned to PD. However, no difference was revealed between any of the polymorphisms studied in the MAO-A and -B genes and PD. Smoking displayed an enviromnental exposure with a strong decreased risk for PD in this study (OR=0.40 for men and OR=0.48 for women) but no obvious interaction with the MAO genotypes could be observed.Mitochondrial dysfunction and oxidative stress have been hypothesized to contribute to the pathogenesis of PD. The superoxide dismutases (SOD) potentially play an important role in PD by detoxifying superoxide radicals in mitochondria. Polymorphisms neither in superoxide dismutase 2 (SOD2) nor mitochondrial complex I subunit, NDUFV2, were associated with PD.An increased risk ratio for CTE was found in smokers with the GSTM1 null genotype (RR=2.5, Cl 95%, 1.4-4.2) or the GSTT1 null genotype (RR=1.4, Ci 95%, 1.02-2.0). In non-smokers GS1M1 null genotype did not confer any risk for CTE. Polymorphisms in mEPHX were not associated with an increased risk for CTE.Thus, various genetic and enviromnental factors most likely influence both PD and solvent-induced CTE. Detoxification pathways may represent important protective mechanisms against reactive intermediates, thus genetic predisposition in these pathways could modify the susceptibility and onset of PD and solvent-induced CTE.
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| 5. |
- Engström, Karin, et al.
(författare)
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Genetic polymorphisms influencing arsenic metabolism: evidence from Argentina.
- 2007
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Ingår i: Environmental Health Perspectives. - : Environmental Health Perspectives. - 1552-9924 .- 0091-6765. ; 115:4, s. 599-605
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Tidskriftsartikel (refereegranskat)abstract
- The susceptibility to arsenic-induced diseases differs greatly between individuals, possibly due to interindividual variations in As metabolism that affect retention and distribution of toxic metabolites. To elucidate the role of genetic factors in As metabolism, we studied how polymorphisms in six genes affected the urinary metabolite pattern in a group of indigenous women (n = 147) in northern Argentina who were exposed to approximately 200 mu g/L As in drinking water. These women had low urinary percentages of monomethylated As (MMA) and high percentages of dimethylated As (DMA). MMA has been associated with adverse health effects, and DMA has the lowest body retention of the metabolites. The genes studied were arsenic(+ 111) methyltransferase (AS3MT), glutathione S-transferase omega 1 (GSTO1), 5-methyltetrahydrofolate-homocysteine methyltransferase (MTR), methylenetetrahydrofolate reductase (MTHFR), and glutathione S-transferases mu I (GSTM1) and theta I (GSTT1). We found three intronic polymorphisms in AS3MT (G12390C, C14215T, and G35991A) associated with a lower percentage of MMA (%MMA) and a higher percentage of DMA (%DMA) in urine. The variant homozygotes showed approximately half the %MMA compared with wild-type homozygotes. These polymorphisms were in strong linkage, with high allelic frequencies (72-76%) compared with other populations. We also saw minor effects of other polymorphisms in the multivariate regression analysis with effect modification for the deletion genotypes for GSTM1 (affecting %MMA) and GSTT1 (affecting %MMA and %DMA). For pregnant women, effect modification was seen for the folate-metabolizing genes MTR and MTHFA In conclusion, these findings indicate that polymorphisms in AS3MT-and possibly GSTM1, GSTT1, MTR, and MTHFR-are responsible for a large part of the interindividual variation in As metabolism and susceptibility.
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| 6. |
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| 7. |
- Malipatlolla, Dilip, 1990, et al.
(författare)
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A fiber-rich diet and radiation-induced injury in the murine intestinal mucosa
- 2022
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Ingår i: International Journal of Molecular Sciences. - : MDPI AG. - 1661-6596 .- 1422-0067. ; 23:1
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Tidskriftsartikel (refereegranskat)abstract
- Dietary fiber is considered a strong intestinal protector, but we do not know whether dietary fiber protects against the long-lasting mucosal damage caused by ionizing radiation. To evaluate whether a fiber-rich diet can ameliorate the long-lasting pathophysiological hallmarks of the irradiated mucosa, C57BL/6J mice on a fiber-rich bioprocessed oat bran diet or a fiber-free diet received 32 Gray in four fractions to the distal colorectum using a linear accelerator and continued on the diets for one, six or 18 weeks. We quantified degenerating crypts, crypt fission, cell proliferation, crypt survival, macrophage density and bacterial infiltration. Crypt loss through crypt degeneration only occurred in the irradiated mice. Initially, it was most frequent in the fiber-deprived group but declined to levels similar to the fiber-consuming group by 18 weeks. The fiber-consuming group had a fast response to irradiation, with crypt fission for growth or healing peaking already at one week post-irradiation, while crypt fission in the fiber-deprived group peaked at six weeks. A fiber-rich diet allowed for a more intense crypt cell proliferation, but the recovery of crypts was eventually lost by 18 weeks. Bacterial infiltration was a late phenomenon, evident in the fiber-deprived animals and intensified manyfold after irradiation. Bacterial infiltration also coincided with a specific proinflammatory serum cytokine profile. In contrast, mice on a fiber-rich diet were completely protected from irradiation-induced bacterial infiltration and exhibited a similar serum cytokine profile as sham-irradiated mice on a fiber-rich diet. Our findings provide ample evidence that dietary fiber consumption modifies the onset, timing and intensity of radiation-induced pathophysiological processes in the intestinal mucosa. However, we need more knowledge, not least from clinical studies, before this finding can be introduced to a new and refined clinical practice.
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| 8. |
- Warholm, Margareta, 1952-
(författare)
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Studies on hepatic glutathione transferases from rat and man : 1. A kinetic mechanism for glutathione transferase A from rat liver. 2. Transferase µ, a new form of glutathione transferase in human liver.
- 1983
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This study of glutathione transferases was undertaken to achieve a better understanding of the catalytic and molecular properties of various isozymes of this group of drug-metabolizing enzymes.The steady-state kinetics of purified glutathione transferase A from rat liver with glutathione (GSH) and 1,2-dichloro- 4-nitrobenzene as substrates, did not follow a simple Michaelis- Menten equation. Inhibition by the product of the enzymatic reaction, as well as by other S-substituted glutathione derivatives, was also nonlinear. The complex kinetics observed were shown not to be the result of partial inhibition of the enzyme by ethanol (a solvent present in the assay system).Binding studies showed that glutathione transferase A can bind GSH, bromosulfophthalein, the product of the enzymatic reaction, or glutathione disulfide with a maximal binding stoichiometry of 2 molecules per protein dimer. No sign of cooperativity was observed.The experimental data of the kinetic and binding studies were analyzed by nonlinear regression analysis.A steady-state sequential mechanism, in which the two substrates bind and the two products leave in random order, is proposed for glutathione transferase A.The isozyme patterns of glutathione transferase in different human adult and fetal livers were investigated by means of isoelectric focusing. All fetal livers contained a basic and an acidic transferase as major constituents. In contrast, multiple basic forms and only minor amounts of acidic transferases were found in adult liver. Some individuals possessed an additional previously unknown glutathione transferase isozyme, with a near-neutral isoelectric point.This new isozyme, transferase µ, was purified to apparent homogeneity. Affinity chromatography on S-hexylglutathione Sepharose 6B was a very efficient step in this purification.The molecular and catalytic properties of transferase µ are distinct from those of the other human transferases, which indicates that transferase µ is a separate gene product. Of particular interest is the high activity of transferase µ towards the epoxides benzo(a)pyrene 4,5-oxide and styrene 7,8- oxide. transferase µ also binds non-substrate ligands, e.g., cholate and bilirubin.
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