| 1. |
- Behre, Carl Johan, 1968, et al.
(författare)
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Dissociation between adipose tissue expression and serum levels of adiponectin during and after diet-induced weight loss in obese subjects with and without the metabolic syndrome
- 2007
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Ingår i: Metabolism: Clinical and Experimental. - : Elsevier BV. - 0026-0495 .- 1532-8600. ; 56:8, s. 1022-8
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Tidskriftsartikel (refereegranskat)abstract
- The study aimed to examine if dysmetabolic subjects (MetS+) have lower adiponectin gene expression and lower circulating adiponectin levels than non-dysmetabolic obese subjects (MetS-) at baseline, if adiponectin expression and adiponectin concentration rise more in the dysmetabolic group during weight loss, and if v-SNARE Vti1a (vesicle transport soluble NSF attachment protein receptor vps10p tail interacting 1a) expression increases during the weight loss, as a mechanism for increased adiponectin secretion. Twenty-one obese MetS+ and 19 obese MetS- subjects underwent a very low-energy diet for 16 weeks followed by 2 weeks of refeeding. Abdominal subcutaneous adipose tissue biopsies and blood samples were taken before, during, and after dieting for DNA microarray, reverse transcriptase-polymerase chain reaction, and biochemical analyses. Serum adiponectin was also assessed in a sex- and age-matched healthy, nonobese reference group. Weight decreased by 26.3+/-9.8 kg in the MetS+ group and 28.2+/-8.4 kg in the MetS- group with concomitant reductions in insulin, hemoglobin A1c, and triglycerides that were more pronounced in the MetS+ group. Initially, the MetS+ subjects had lower serum adiponectin, but the differences disappeared at week 8, with a continuous increase in serum adiponectin throughout the study in both groups to a level that was higher than in the reference group. The expression of adiponectin and v-SNARE Vti1a did not differ between the groups or over time. In conclusion, obese subjects with the metabolic syndrome had lower circulating adiponectin than subjects without the syndrome. Weight loss increased serum levels of adiponectin without a parallel increase in adiponectin gene expression. The mechanisms involved in the regulation of adiponectin levels merits further investigation.
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| 2. |
- Behre, Carl Johan, 1968, et al.
(författare)
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Hypoxia-inducible factor 1 is correlated to serum adiponectin levels and measures of obesity and insulin sensitivity in vivo
- 2009
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Ingår i: International Congress on Prediabetes and the Metabolic Syndrome.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Title: Hypoxia-inducible factor 1 is correlated to serum adiponectin levels and measures of obesity and insulin sensitivity in vivo Background: Hypoxia has been shown to decrease adiponectin in vitro. Adiponectin levels are negatively associated to type 2 diabetes and cardiovascular diseases. Recently, it was shown that Hypoxia-inducible factor 1α (HIF-1) regulates adiponectin expression in murine cardiomyocytes. The present study was performed to examine the association between HIF-1 expression and serum adiponectin levels, measures of adiposity and insulin resistance in humans. Methods: Abdominal subcutaneous adipose tissue biopsies were obtained from 24 subjects diagnosed with and without the metabolic syndrome. HIF-1 gene expression was assessed by individual DNA microarray analyses. Adipose tissue depots were assessed with computerized tomography. Anthropometrics were performed. Circulating levels of insulin, adiponectin, leptin, cholesterol, high-sensitivity C - reactive protein (hs-CRP) and fasting levels of insulin and glucose were measured by standard laboratory procedures. Results: In a univariate analysis, HIF-1 expression levels correlate to BMI (r=0.42, p=0.04), WHR (r=0.55, p=0.0058), total adipose tissue (r=0.46, p=0.022), subcutaneous adipose tissue ( r=0.49, p= 0.016),liver fat (r=0.44, p=0.030), fasting insulin (r=0.46, p=0.023), HOMA-index (r=0.46, p=0.023) and serum adiponectin (r= -0.42, p=0.0418). We observed no statistically significant correlations between HIF-1 gene expression and visceral adipose tissue, systolic blood pressure, serum cholesterol, hs-CRP or serum leptin. HIF-1 gene expression did not differ between the groups. Conclusions: We report that expression of HIF-1 is correlated to serum adiponectin, insulin sensitivity and measures of adiposity. There were no statistical differences in expression of HIF-1 between subjects with or without the metabolic syndrome. In this cross-sectional analysis, no conclusions can be drawn about causality.
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| 3. |
- Gummesson, Anders, 1973, et al.
(författare)
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Adipose tissue is not an important source for matrix metalloproteinase-9 in the circulation.
- 2009
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Ingår i: Scandinavian journal of clinical and laboratory investigation. - 1502-7686 .- 0036-5513. ; 69:6, s. 636-42
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: Matrix metalloproteinase 9 (MMP-9) is overexpressed in atherosclerotic plaques and in many cancers, and has emerged as a potential circulating biomarker for such diseases. However, adipose tissue (AT) might also produce circulating MMP-9, thereby reducing the value of MMP-9 as a biomarker. The aim of this study was to evaluate the impact of AT on circulating MMP-9, and if the metabolic syndrome might have a modifying effect. METHODS: Gene expression of MMP-9 was measured in AT, isolated adipocytes, atherosclerotic plaques, macrophages and various other human tissues using real-time PCR. Relationships between plasma MMP-9 (ELISA), adiposity, and metabolic syndrome were analyzed in a population-based cohort of 61-year-old men (n=513). Both AT mRNA levels and circulating levels of MMP-9 were measured in obese subjects (n=40) with and without the metabolic syndrome, treated with a weight-reducing diet. RESULTS: Bone marrow, atherosclerotic plaques and macrophages had considerably higher MMP-9 mRNA than subcutaneous AT and isolated adipocytes. Among the 61-year-old men, active plasma MMP-9 concentrations were associated with several metabolic syndrome factors, and inflammatory markers, but not body mass index (BMI). In obese patients with, but not without metabolic syndrome AT mRNA levels and circulating MMP-9 declined during weight reduction, but there was no association between changes in plasma MMP-9 and BMI. CONCLUSION: The results show that adipose tissue per se is not associated with circulating MMP-9. Components of the metabolic syndrome, such as circulating insulin and glucose were related to plasma MMP-9 both in the observation and dietary weight loss studies.
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| 4. |
- Gummesson, Anders, 1973
(författare)
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Pathogenesis of Obesity and Effects of Treatment. Clinical and Molecular Studies on Body Fat, Energy Balance, and Weight Loss.
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Obesity is common and related to many health problems including various forms of cancer. The condition arises from the imbalance between food intake and energy expenditure, and is strongly influenced by genetic factors. Weight loss has several health benefits, but for many of the obesity-related diseases such as cancer, the impact of obesity treatment is not clarified. Unfortunately, weight loss is in most cases difficult to sustain, and obesity treatment today is insufficient. The adipose tissue and the gastrointestinal tract play active roles in the regulation of whole-body energy balance, and therapeutic targets for the treatment of obesity may be found within these sites. Also, these organs may be responsible for mediating some of the adverse effects of obesity. Special attention has been drawn to visceral adipose tissue, i.e. the fat surrounding the intestines, as being particularly harmful. The aim of this thesis was to increase our understanding of the mechanisms behind human obesity and the consequences of obesity treatment. We used population-based cross-sectional studies, as well as longitudinal intervention studies with short- and long-term weight loss. CIDEA and CIDEC are two genes with putative functions in adipose tissue, and we therefore studied their transcriptional regulation in relation to energy balance and body composition as an attempt to elucidate their role in human obesity. The genes were predominantly expressed in adipose tissue as compared to other human tissues, both CIDEA and CIDEC gene transcription were highly responsive to changes in energy availability, and CIDEA correlated with body fat and insulin levels. CIDEA expression also correlated with basal metabolic rate and uncoupling protein 1, suggesting a role in the regulation of energy expenditure. In gene silencing experiments in cultured adipocytes, we showed that CIDEC is involved in the regulation of basal as well as stimulated lipolysis, and mitochondrial fatty acid oxidation. Together, our results support a role of CIDEC and CIDEA in human obesity. There are indications that impaired intestinal barrier with increased passage of gut-derived antigens may drive visceral adipose tissue accumulation, and we therefore investigated if increased intestinal permeability is associated with visceral obesity in humans. Study subjects were recruited from a population-based cohort of Swedish women. Intestinal permeability was assessed using the urinary excretion of orally ingested sucralose and mannitol. We used computed tomography to measure visceral and liver fat. Intestinal permeability of the large intestine correlated with visceral fat area (P=0.0003) and liver fat content (P=0.004). The results indicate that gut leakiness should be further explored as a possible cause of visceral fat accumulation. The Swedish Obese Subjects (SOS) study in combination with the Swedish National Cancer Register makes it possible to, for the first time, study the effects of bariatric surgery on cancer incidence in a prospective, controlled study setting. The SOS study started in 1987 and involves severely obese subjects, 2010 of which underwent bariatric surgery, and 2037 contemporaneously matched obese controls who received conventional treatment. Bariatric surgery resulted in a sustained weight reduction, whereas the average weight change in the control group was minimal. In women, the number of first-time cancers during on average 11 years after inclusion was lower in the surgery group compared to the control group (HR= 0.58, 95% CI: 0.44-0.77, p<0.001). In men, we could not detect any difference between treatment groups (HR=0.97, p=0.91). In summary, the results of this thesis suggest that the CIDEA and CIDEC genes play a role in obesity, impaired intestinal barrier function contributes to visceral fat accumulation, and bariatric surgery reduces the risk of developing cancer in severely obese women.
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| 5. |
- Gummesson, Anders, 1973, et al.
(författare)
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Relations of Adipose Tissue Cell Death-Inducing DFFA-like Effector A Gene Expression to Basal Metabolic Rate, Energy Restriction and Obesity: Population-based and Dietary Intervention Studies.
- 2007
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Ingår i: Journal of Clinical Endocrinology and Metabolism. - : The Endocrine Society. - 0021-972X .- 1945-7197. ; 92:12, s. 4759-65
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Tidskriftsartikel (refereegranskat)abstract
- Context: Cell death-inducing DFFA-like effector A (CIDEA) could be a potential target for the treatment of obesity via the modulation of metabolic rate, based on the findings that CIDEA inhibits the brown adipose tissue uncoupling process in rodents. Objective: To investigate the putative link between CIDEA and basal metabolic rate in humans, and to further elucidate the role of CIDEA in human obesity. Design: We have explored CIDEA gene expression in adipose tissue in two different human studies: A cross-sectional and population-based study assessing body composition and metabolic rate (Mölndal Metabolic study, n=92), and a longitudinal intervention-study of obese subjects treated with a very low calorie diet (VLCD study, n=24). Results: The CIDEA gene was predominantly expressed in adipocytes as compared to other human tissues. CIDEA gene expression in adipose tissue was inversely associated with basal metabolic rate independently of body composition, age and gender (p=0.014). VLCD induced an increase in adipose tissue CIDEA expression (p<0.0001) with a subsequent decrease in response to refeeding (p<0.0001). Reduced CIDEA gene expression was associated with a high body fat content (p<0.0001) and with high insulin levels (p<0.01). No dysregulation of CIDEA expression was observed in individuals with the metabolic syndrome when compared with BMI-matched controls. In a separate sample of VLCD-treated subjects (n=10), uncoupling protein 1 expression was reduced during diet (p=0.0026) and inversely associated with CIDEA expression (p=0.0014). Conclusion: The findings are consistent with the concept that CIDEA plays a role in adipose tissue energy expenditure.
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| 6. |
- Kos, K., et al.
(författare)
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Regulation of the fibrosis and angiogenesis promoter SPARC/osteonectin in human adipose tissue by weight change, leptin, insulin, and glucose : Regulation of SPARC in human adipose tissue
- 2009
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Ingår i: Diabetes. - : American Diabetes Association. - 1939-327X .- 0012-1797. ; 58:8, s. 1780-8
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: Matricellular Secreted Protein, Acidic and Rich in Cysteine (SPARC), originally discovered in bone as osteonectin, is a mediator of collagen deposition and promotes fibrosis. Adipose tissue collagen has recently been found to be linked with metabolic dysregulation. Therefore, we tested the hypothesis that SPARC in human adipose tissue is influenced by glucose metabolism and adipokines. RESEARCH DESIGN AND METHODS: Serum and adipose tissue biopsies were obtained from morbidly obese nondiabetic subjects undergoing bariatric surgery and lean control subjects for analysis of metabolic markers, SPARC, and various cytokines (RT-PCR). Additionally, 24 obese subjects underwent a very-low-calorie diet of 1,883 kJ (450 kcal)/day for 16 weeks and serial subcutaneous-abdominal-adipose tissue (SCAT) biopsies (weight loss: 28 +/- 3.7 kg). Another six lean subjects underwent fast-food-based hyperalimentation for 4 weeks (weight gain: 7.2 +/- 1.6 kg). Finally, visceral adipose tissue explants were cultured with recombinant leptin, insulin, and glucose, and SPARC mRNA and protein expression determined by Western blot analyses. RESULTS: SPARC expression in human adipose tissue correlated with fat mass and was higher in SCAT. Weight loss induced by very-low-calorie diet lowered SPARC expression by 33% and increased by 30% in adipose tissue of subjects gaining weight after a fast-food diet. SPARC expression was correlated with leptin independent of fat mass and correlated with homeostasis model assessment-insulin resistance. In vitro experiments showed that leptin and insulin potently increased SPARC production dose dependently in visceral adipose tissue explants, while glucose decreased SPARC protein. CONCLUSIONS: Our data suggest that SPARC expression is predominant in subcutaneous fat and its expression and secretion in adipose tissue are influenced by fat mass, leptin, insulin, and glucose. The profibrotic effects of SPARC may contribute to metabolic dysregulation in obesity.
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| 7. |
- Magnusson, Björn, 1976, et al.
(författare)
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Cell death-inducing DFF45-like effector C is reduced by caloric restriction and regulates adipocyte lipid metabolism.
- 2008
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Ingår i: Metabolism: clinical and experimental. - : Elsevier BV. - 1532-8600. ; 57:9, s. 1307-13
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Tidskriftsartikel (refereegranskat)abstract
- Members of the cell death-inducing DFF45-like effector (CIDE) gene family have been shown to regulate lipid metabolism. In this article, we report that the third member of the human CIDE family, CIDEC, is down-regulated in response to a reduced caloric intake. The down-regulation was demonstrated by microarray and real-time polymerase chain reaction analysis of subcutaneous adipose tissue in 2 independent studies on obese patients undergoing treatment with a very low calorie diet. By analysis of CIDEC expression in 65 human tissues, we conclude that human CIDEC is predominantly expressed in subcutaneous adipocytes. Together, these observations led us to investigate the effect of decreased CIDEC expression in cultured 3T3-L1 adipocytes. Small interfering RNA-mediated knockdown of CIDEC resulted in an increased basal release of nonesterified fatty acids, decreased responsiveness to adrenergic stimulation of lipolysis, and increased oxidation of endogenous fatty acids. Thus, we suggest that CIDEC is a regulator of adipocyte lipid metabolism and may be important for the adipocyte to adapt to changes in energy availability.
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| 8. |
- Olson, Fredrik J., 1975, et al.
(författare)
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Circulating matrix metalloproteinase 9 levels in relation to sampling methods, femoral and carotid atherosclerosis.
- 2008
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Ingår i: Journal of internal medicine. - : Wiley. - 1365-2796 .- 0954-6820. ; 263:6, s. 626-35
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: To examine whether circulating levels of matrix metalloproteinase 9 (MMP-9) were associated with ultrasound-assessed intima-media thickness (IMT) and echolucent plaques in the carotid and femoral arteries. To examine preanalytical sources of variability in MMP-9 concentrations related to sampling procedures. SUBJECTS AND DESIGN: Plasma and serum MMP-9 levels were compared with ultrasound assessed measures of femoral and carotid atherosclerosis, in a cross-sectional study of 61-year-old men (n = 473). Preanalytical sources of variability in MMP-9 levels were examined in 10 healthy subjects. Main outcome measures were circulating levels of MMP-9 in serum and plasma, IMT of the carotid and femoral arteries, and plaque status based on size and echolucency. SETTING: Research unit at university hospital. RESULTS: Plasma concentrations of total and active MMP-9 were associated with femoral artery IMT independently of traditional cardiovascular risk factors, and were higher in subjects with moderate to large femoral plaques. Plasma MMP-9 concentration was higher in men with echolucent femoral plaques (P = 0.006) compared with subjects without femoral plaques. No similar associations were found for carotid plaques. MMP-9 concentrations were higher in serum than in plasma, and higher when sampling was performed with Vacutainer than with syringe. MMP-9 levels in serum were more strongly associated with peripheral neutrophil count compared with MMP-9 levels in plasma. CONCLUSIONS: Plasma MMP-9 levels were associated with atherosclerosis in the femoral artery, and total MMP-9 concentration was higher in men with echolucent femoral plaques. The choice of sample material and sampling method affect the measurements of circulating MMP-9 levels.
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| 9. |
- Palming, Jenny, 1975, et al.
(författare)
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The expression of NAD(P)H:quinone oxidoreductase 1 is high in human adipose tissue, reduced by weight loss, and correlates with adiposity, insulin sensitivity, and markers of liver dysfunction.
- 2007
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Ingår i: The Journal of clinical endocrinology and metabolism. - : The Endocrine Society. - 0021-972X .- 1945-7197. ; 92:6, s. 2346-52
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Tidskriftsartikel (refereegranskat)abstract
- CONTEXT: We have previously identified nicotinamide adenine dinucleotide phosphate:quinone oxidoreductase 1 (NQO1), an enzyme involved in the protection against oxidative stress, as a gene predominantly expressed in human adipocytes. Studies in mice deficient in NQO1 activity suggest that NQO1 may also play an important role in metabolism. OBJECTIVE: The aim of this study was to explore the expression and regulation of NQO1 in human adipose tissue (AT) and isolated adipocytes. PATIENTS AND RESULTS: The high expression of NQO1 in adipocytes was verified in human adipocytes and AT by real-time PCR. DNA microarray analysis showed that NQO1 was expressed at higher levels in large compared with small adipocytes, isolated from the same fat biopsy. Furthermore, NQO1 mRNA levels were positively correlated with adipocyte size (n = 7; P < 0.002). During an 18-wk diet regime (n = 24; mean weight loss 27 kg), the NQO1 expression in human sc AT was down-regulated (P < 0.0001), and mRNA levels correlated with body mass index (P = 0.0005), sc, and total abdominal AT areas, as determined by computerized tomography (P < 0.0001, both) and metabolic parameters. NQO1 mRNA levels were also positively correlated with aspartate aminotransferase (P = 0.0028) and alanine aminotransferase (P = 0.0219), markers known to be associated with severity of hepatic steatosis. CONCLUSIONS: NQO1 is highly expressed in human AT, particularly in large adipocytes. AT NQO1 expression is reduced during diet-induced weight loss, and the expression levels positively correlate with adiposity, glucose tolerance, and markers of liver dysfunction. Together, these findings indicate a role for NQO1 in the metabolic complications of human obesity.
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| 10. |
- Saiki, Atsuhito, et al.
(författare)
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Tenomodulin is highly expressed in adipose tissue, increased in obesity, and down-regulated during diet-induced weight loss.
- 2009
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Ingår i: The Journal of clinical endocrinology and metabolism. - : The Endocrine Society. - 1945-7197 .- 0021-972X. ; 94:10, s. 3987-94
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Tidskriftsartikel (refereegranskat)abstract
- CONTEXT: Tenomodulin (TNMD), a putative angiogenesis inhibitor, is expressed in hypovascular connective tissues. Global gene expression scans show that the TNMD gene also is expressed in human adipose tissue and that its expression is regulated in response to weight reduction; however, more detailed information is lacking. OBJECTIVE: The aim of this study was to investigate TNMD tissue distribution and TNMD gene expression in human adipose tissue in relation to obesity and metabolic disease. DESIGN, PATIENTS, AND INTERVENTIONS: TNMD gene expression, tissue distribution, and TNMD gene expression in adipose tissue from different depots, from lean and obese subjects, and during diet-induced weight reduction were analyzed by DNA microarray and real-time PCR. MAIN OUTCOME MEASURE: We primarily measured TNMD gene expression. RESULTS: The TNMD gene was predominantly expressed in sc adipose tissue. TNMD gene expression was higher in sc than omental adipose tissue both in lean (P = 0.002) and obese subjects (P = 0.014). In both women and men, TNMD gene expression was significantly higher in the obese subjects compared to the lean subjects (P = 1.1 x 10(-26) and P = 0.010, respectively). In a multiple linear regression analysis, BMI was a significant independent predictor of TNMD gene expression. TNMD gene expression was down-regulated during diet-induced weight loss, with a 65% decrease after 18 wk of diet (P < 0.0001). CONCLUSIONS: We conclude that human adipose tissue TNMD gene expression is highly affected by obesity, adipose tissue location, and weight loss, indicating that TNMD may play a role in adipose tissue function.
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