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- Back, S E, et al.
(author)
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Age dependence of renal function: clearance of iohexol and p-amino hippurate in healthy males
- 1989
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In: Scandinavian Journal of Clinical & Laboratory Investigation. - 1502-7686. ; 49:7, s. 641-646
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Journal article (peer-reviewed)abstract
- Iohexol, a newly developed non-ionic contrast agent, has been recently documented as a reliable glomerular filtration marker. This study describes the age dependence of the single injection clearance of iohexol in a sample of healthy male volunteers ranging from 21 to 77 years of age. In parallel, renal plasma flow was studied by measuring the total clearance of p-amino hippuric acid administered as a continuous infusion. In subjects older than 50 years a negative correlation to age was found for both p-amino hippuric acid and iohexol clearance, with a reduction of 52 ml/min and 12 ml/min per decade, respectively, whereas no age dependence was found for younger subjects. Correlation between p-amino hippuric acid and iohexol clearances was 0.81. However, the filtration fraction, defined as the ratio of iohexol to p-amino hippuric acid clearance, was higher in the elderly subjects. A consistent discrepancy was found between total and renal clearances of p-amino hippuric acid, indicating significant renal metabolism. Renal clearance of creatinine was poorly correlated to iohexol clearance and did not show any relationship to age.
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- Berntorp, Erik, et al.
(author)
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Treatment of haemophilia A and B and von Willebrand's disease : summary and conclusions of a systematic review as part of a Swedish health-technology assessment
- 2012
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In: Haemophilia. - : Wiley. - 1351-8216 .- 1365-2516. ; 18:2, s. 158-165
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Research review (peer-reviewed)abstract
- In an ongoing health-technology assessment of haemophilia treatment in Sweden, performed by the governmental agency Dental and Pharmaceutical Benefits Agency (TLV; tandvårds-och läkemedelsförmånsverket), the Swedish Council on Health Technology Assessment (SBU; statens beredning för medicinsk utvärdering) was called upon to evaluate treatment of haemophilia A and B and von Willebrand's disease (VWD) with clotting factor concentrates. To evaluate the following questions: What are the short-term and long-term effects of different treatment strategies? What methods are available to treat haemophilia patients that have developed inhibitors against factor concentrates? Based on the questions addressed by the project, a systematic database search was conducted in PubMed, NHSEED, Cochrane Library, EMBASE and other relevant databases. The literature search covered all studies in the field published from 1985 up to the spring of 2010. In most instances, the scientific evidence is insufficient for the questions raised in the review. Concentrates of coagulation factors have good haemostatic effects on acute bleeding and surgical intervention in haemophilia A and B and VWD, but conclusions cannot be drawn about possible differences in the effects of different dosing strategies for acute bleeding and surgery. Prophylaxis initiated at a young age can prevent future joint damage in persons with haemophilia. The available treatment options for inhibitors have been insufficiently assessed. The economic consequences of various treatment regimens have been insufficiently analysed. Introduction of national and international registries is important.
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- Björk, Thomas, et al.
(author)
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Rapid exponential elimination of free prostate-specific antigen contrasts the slow, capacity-limited elimination of PSA complexed to alpha 1-antichymotrypsin from serum
- 1998
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In: Urology. - 1527-9995. ; 51:1, s. 57-62
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Journal article (peer-reviewed)abstract
- OBJECTIVES: To study the rates of elimination of total prostate-specific antigen (PSA-T), free PSA (PSA-F), and PSA complexed to alpha 1-antichymotrypsin (PSA-ACT) from blood after radical retropubic prostatectomy (RRP). METHODS: We obtained venous blood from 10 patients with prostate cancer who were undergoing RRP. We analyzed PSA-F and PSA-ACT and equimolar detection of both of these forms together (PSA-T) by using immunofluorometric assays. An attempt was made to fit the serum concentrations of PSA-F, PSA-ACT, and PSA-T for each patient to exponential curves by applying one- and two-compartment models for pharmacokinetic analysis. RESULTS: Manipulation of the prostate during RRP resulted in a 3- to 28-fold increase in PSA-F concentrations in serum. Removal of the prostate resulted in a rapid, biexponential elimination of PSA-F from serum, corresponding to a mean initial (alpha) half-life of 0.81 hours and a mean terminal (beta) half-life of 13.9 hours. Serum PSA-ACT concentrations decreased by 20% to 40% immediately after removal of the gland; the elimination after surgery was slow and nonexponential, corresponding to a mean rate of 0.8 ng/mL/day. The elimination of PSA-T reflects a combination of the elimination patterns for PSA-F and PSA-ACT. CONCLUSIONS: The main proportion of PSA-F is rapidly eliminated from serum, possibly by glomerular filtration. PSA-F released during surgery did not form complexes with ACT, as suggested by the lack of PSA-ACT elevation in serum. The size (approximately 90 kDa) and the extensive in vitro stability of the PSA-ACT complex prevents renal clearance. The nonexponential elimination of the PSA-ACT complex is evidence of a capacity-limited process (e.g., metabolic transformation).
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- Björk, Thomas, et al.
(author)
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Similar rates of exponential decrease in serum concentrations of free prostate-specific antigen (PSA), PSA complexed to alpha-1-antichymotrypsin, and human glandular kallikrein 2 (hK2) in prostate cancer patients treated with GnRH-analogues
- 2001
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In: The Prostate. - : Wiley. - 0270-4137. ; 47:1, s. 14-20
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Journal article (peer-reviewed)abstract
- BACKGROUND: Our recently reported finding of rapid bi-exponential elimination of free prostate-specific antigen (PSA) after radical retropubic prostatectomy in patients with moderately elevated PSA levels, which contrasted a very slow, linear elimination of PSA complexed to alpha-1-antichymotrypsin (ACT), prompted us to study whether these elimination rates were applicable for patients selected for castration treatment with very high pretreatment concentrations of PSA in serum. In addition, serum concentrations of hK2, the activator of proPSA, were measured. METHODS: Pretreatment serum was obtained from 21 previously untreated prostate cancer patients due for hormonal treatment with a GnRH-analog. Samples were also collected during treatment up to a minimum of 24 weeks at 2-week intervals and analyzed with immunofluorometric assays for free PSA (PSA-F), PSA complexed to alpha-1-antichymotrypsin (PSA-ACT), total PSA (PSA-T), and human kallikrein 2 (hK2). For pharmaco-kinetic analysis the serum concentrations of hK2 and PSA forms for each patient were plotted against time both before and after logarithmic transformation and the half-lives were calculated as ln2/k. RESULTS: Median pretreatment serum concentrations were 322 ng/ml (range, 1.9-2210) for PSA-T, 27.8 ng/ml (range, 1.14-259) for PSA-F, and 207 ng/ml (range, 0.8-2080) for PSA-ACT. All patients had castrate levels of serum testosterone (< 2.5 nmol/l) in less than 21 days after initiation of GnRH-analog treatment. It was possible to evaluate data from 19/21 patients which showed an exponential decrease of all PSA concentrations in serum, with mean half-lives of 12.9 days (range, 7.3-30) for PSA-T, 15.5 days (range, 7.7-37.5) for PSA-F, and 12.3 days (range, 6.6-30) for PSA-ACT. Median pretreatment percent free PSA (PSA-F/PSA-T) was 12% compared to 18% at nadir. The median pretreatment level of hK2 was 3.5 ng/ml (range, 0.29-30.3). There was an exponential decrease in hK2 concentrations in serum after initiation of hormonal treatment with a mean half-life of 18.7 days (range, 7.5-37.5). CONCLUSIONS: For the majority of patients with hormonally treated prostate cancer the serum concentrations of PSA-T, PSA-F, PSA-ACT, and hK2 decreased slowly in parallel and mono-exponentially after initiation of treatment. Mean half-lives were between 12 and 19 days.
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- Chen, Hao Yu, et al.
(author)
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Association of FADS1/2 Locus Variants and Polyunsaturated Fatty Acids With Aortic Stenosis
- 2020
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In: JAMA cardiology. - : American Medical Association (AMA). - 2380-6583 .- 2380-6591. ; 5:6, s. 694-702
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Journal article (peer-reviewed)abstract
- Importance: Aortic stenosis (AS) has no approved medical treatment. Identifying etiological pathways for AS could identify pharmacological targets.Objective: To identify novel genetic loci and pathways associated with AS.Design, Setting, and Participants: This genome-wide association study used a case-control design to evaluate 44 703 participants (3469 cases of AS) of self-reported European ancestry from the Genetic Epidemiology Research on Adult Health and Aging (GERA) cohort (from January 1, 1996, to December 31, 2015). Replication was performed in 7 other cohorts totaling 256 926 participants (5926 cases of AS), with additional analyses performed in 6942 participants from the Cohorts for Heart and Aging Research in Genomic Epidemiology (CHARGE) Consortium. Follow-up biomarker analyses with aortic valve calcium (AVC) were also performed. Data were analyzed from May 1, 2017, to December 5, 2019.Exposures: Genetic variants (615 643 variants) and polyunsaturated fatty acids (ω-6 and ω-3) measured in blood samples.Main Outcomes and Measures: Aortic stenosis and aortic valve replacement defined by electronic health records, surgical records, or echocardiography and the presence of AVC measured by computed tomography.Results: The mean (SD) age of the 44 703 GERA participants was 69.7 (8.4) years, and 22 019 (49.3%) were men. The rs174547 variant at the FADS1/2 locus was associated with AS (odds ratio [OR] per C allele, 0.88; 95% CI, 0.83-0.93; P = 3.0 × 10-6), with genome-wide significance after meta-analysis with 7 replication cohorts totaling 312 118 individuals (9395 cases of AS) (OR, 0.91; 95% CI, 0.88-0.94; P = 2.5 × 10-8). A consistent association with AVC was also observed (OR, 0.91; 95% CI, 0.83-0.99; P = .03). A higher ratio of arachidonic acid to linoleic acid was associated with AVC (OR per SD of the natural logarithm, 1.19; 95% CI, 1.09-1.30; P = 6.6 × 10-5). In mendelian randomization, increased FADS1 liver expression and arachidonic acid were associated with AS (OR per unit of normalized expression, 1.31 [95% CI, 1.17-1.48; P = 7.4 × 10-6]; OR per 5-percentage point increase in arachidonic acid for AVC, 1.23 [95% CI, 1.01-1.49; P = .04]; OR per 5-percentage point increase in arachidonic acid for AS, 1.08 [95% CI, 1.04-1.13; P = 4.1 × 10-4]).Conclusions and Relevance: Variation at the FADS1/2 locus was associated with AS and AVC. Findings from biomarker measurements and mendelian randomization appear to link ω-6 fatty acid biosynthesis to AS, which may represent a therapeutic target.
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- Chen, H.Y., et al.
(author)
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Dyslipidemia, inflammation, calcification, and adiposity in aortic stenosis: a genome-wide study
- 2023
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In: European Heart Journal. - : Oxford University Press. - 0195-668X .- 1522-9645. ; 44:21, s. 1927-1939
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Journal article (peer-reviewed)abstract
- Aims Although highly heritable, the genetic etiology of calcific aortic stenosis (AS) remains incompletely understood. The aim of this study was to discover novel genetic contributors to AS and to integrate functional, expression, and cross-phenotype data to identify mechanisms of AS. Methods and results A genome-wide meta-analysis of 11.6 million variants in 10 cohorts involving 653 867 European ancestry participants (13 765 cases) was performed. Seventeen loci were associated with AS at P ≤ 5 × 10−8, of which 15 replicated in an independent cohort of 90 828 participants (7111 cases), including CELSR2–SORT1, NLRP6, and SMC2. A genetic risk score comprised of the index variants was associated with AS [odds ratio (OR) per standard deviation, 1.31; 95% confidence interval (CI), 1.26–1.35; P = 2.7 × 10−51] and aortic valve calcium (OR per standard deviation, 1.22; 95% CI, 1.08–1.37; P = 1.4 × 10−3), after adjustment for known risk factors. A phenome-wide association study indicated multiple associations with coronary artery disease, apolipoprotein B, and triglycerides. Mendelian randomization supported a causal role for apolipoprotein B-containing lipoprotein particles in AS (OR per g/L of apolipoprotein B, 3.85; 95% CI, 2.90–5.12; P = 2.1 × 10−20) and replicated previous findings of causality for lipoprotein(a) (OR per natural logarithm, 1.20; 95% CI, 1.17–1.23; P = 4.8 × 10−73) and body mass index (OR per kg/m2, 1.07; 95% CI, 1.05–1.9; P = 1.9 × 10−12). Colocalization analyses using the GTEx database identified a role for differential expression of the genes LPA, SORT1, ACTR2, NOTCH4, IL6R, and FADS. Conclusion Dyslipidemia, inflammation, calcification, and adiposity play important roles in the etiology of AS, implicating novel treatments and prevention strategies. © The Author(s) 2023. Published by Oxford University Press on behalf of the European Society of Cardiology.
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