| 1. |
- Bergström, Staffan, et al.
(författare)
-
Extracting syringe for extraction of phthalate esters in aqueous environmental samples
- 2007
-
Ingår i: Analytica Chimica Acta. - : Elsevier BV. - 1873-4324 .- 0003-2670. ; 594:2, s. 240-247
-
Tidskriftsartikel (refereegranskat)abstract
- The use of the extracting syringe (ESy), a fully automated membrane-based extraction technique, for analysis of phthalate esters in complex aqueous samples has been investigated. The ESy, working as an autosampler that combines the extraction process and injection into the gas chromatograph (GC) in one single step, is placed on top of the GC equipped with a flame ionisation detector. The aqueous samples are loaded in a tray and automatically extracted by employing microporous membrane liquid-liquid extraction principle. After the extraction, the extract is directly injected into the GC's programmable temperature vaporisation injector. Six different phthalate esters were used as model compounds. Four extraction solvents were tested and the addition of sample organic modifier was examined. Toluene was the optimal solvent to use for extraction. Due to the large variation in polarity of phthalate esters, 50% methanol as organic modifier had to be added to the samples so as to extract the most nonpolar phthalate esters; di-2-ethylhexylphthalate and di-n-octylphthalate, whereas the other four relatively polar phthalate esters were extracted from unmodified samples. No significant difference between extraction of river water, leachate water from a landfill and reagent water was noted, except for minor deviations. The extraction time was 20 min for extraction of a 1-mL sample, resulting in a good linearity for all aqueous media investigated, good enrichment factors (54-110 folds) and low LOD values (0.2-10 ng mL(-1)) and relative standard deviation (%R.S.D.; 0.9-3.7%).
|
|
| 2. |
- Kanatsuna, N, et al.
(författare)
-
Doubly reactive INS-IGF2 autoantibodies in children with newly diagnosed autoimmune (type 1) diabetes
- 2015
-
Ingår i: Scandinavian Journal of Immunology. - : Wiley-Blackwell. - 0300-9475 .- 1365-3083. ; 82:4, s. 361-369
-
Tidskriftsartikel (refereegranskat)abstract
- The splice variant INS-IGF2 entails the preproinsulin signal peptide, the insulin B-chain, eight amino acids of the C-peptide and 138 unique amino acids from an ORF in the IGF2 gene. The aim of this study was to determine whether levels of specific INS-IGF2 autoantibodies (INS-IGF2A) were related to age at diagnosis, islet autoantibodies, HLA-DQ or both, in patients and controls with newly diagnosed type 1 diabetes. Patients (n = 676), 0-18 years of age, diagnosed with type 1 diabetes in 1996-2005 and controls (n = 363) were analysed for specific INS-IGF2A after displacement with both cold insulin and INS-IGF2 to correct for non-specific binding and identify double reactive sera. GADA, IA-2A, IAA, ICA, ZnT8RA, ZnT8WA, ZnT8QA and HLA-DQ genotypes were also determined. The median level of specific INS-IGF2A was higher in patients than in controls (P < 0.001). Irrespective of age at diagnosis, 19% (126/676) of the patients had INS-IGF2A when the cut-off was the 95th percentile of the controls (P < 0.001). The risk of INS-IGF2A was increased among HLA-DQ2/8 (OR = 1.509; 95th CI 1.011, 2.252; P = 0.045) but not in 2/2, 2/X, 8/8, 8/X or X/X (X is neither 2 nor 8) patients. The association with HLA-DQ2/8 suggests that this autoantigen may be presented on HLA-DQ trans-heterodimers, rather than cis-heterodimers. Autoantibodies reactive with both insulin and INS-IGF2A at diagnosis support the notion that INS-IGF2 autoimmunity contributes to type 1 diabetes.
|
|
| 3. |
- Lindehammer, Sabina, et al.
(författare)
-
Temporal trends of HLA genotype frequencies of type 1 diabetes patients in Sweden from 1986 to 2005 suggest altered risk
- 2008
-
Ingår i: Acta Diabetologica. - : Springer Science and Business Media LLC. - 0940-5429 .- 1432-5233. ; 45:4, s. 231-5
-
Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to compare the frequency of human leukocyte antigen (HLA) genotypes in 1-18-year-old patients with type 1 diabetes newly diagnosed in 1986-1987 (n = 430), 1996-2000 (n = 342) and in 2003-2005 (n = 171). We tested the hypothesis that the HLA DQ genotype distribution changes over time. Swedish type 1 diabetes patients and controls were typed for HLA using polymerase chain reaction amplification and allele specific probes for DQ A1* and B1* alleles. The most common type 1 diabetes HLA DQA1*-B1*genotype 0501-0201/0301-0302 was 36% (153/430) in 1986-1987 and 37% (127/342) in 1996-2000, but decreased to 19% (33/171) in 2003-2005 (P \ 0.0001). The 0501-0201/0501-0201 genotype increased from 1% in 1986-1987 to 7% in 1996-2000 (P = 0.0047) and to 5% in 2003-2005 (P > 0.05). This study in 1-18-year-old Swedish type 1 diabetes patients supports the notion that there is a temporal change in HLA risk.
|
|
| 4. |
- Lundgren, Markus, et al.
(författare)
-
Reduced morbidity at diagnosis and improved glycemic control in children previously enrolled in DiPiS follow-up
- 2014
-
Ingår i: Pediatric Diabetes. - : Hindawi Limited. - 1399-543X. ; 15:7, s. 494-501
-
Tidskriftsartikel (refereegranskat)abstract
- Aims/hypothesis: Children participating in longitudinal type 1 diabetes prediction studies were reported to have less severe disease at diabetes diagnosis. Our aim was to investigate children who from birth participated in the Diabetes Prediction in Skane (DiPiS) study for metabolic status at diagnosis and then continued to be followed for 2 yr of regular clinical care. Methods: Children, followed in DiPiS before diagnosis, were compared to children in the same birth cohort, who did not participate in follow-up. Metabolic status, symptoms at diagnosis as well as hemoglobin A1c (HbA1c) and doses of insulin at 3, 6, 12, and 24 months after diagnosis were compared. Results: Children, followed in DiPiS and diagnosed at 2-12 yr of age, had 0.8% (9 mmol/mol) lower HbA1c at diagnosis than those who were not followed (p=0.006). At diagnosis, fewer DiPiS children had symptoms (p=0.014) and ketoacidosis at diagnosis were reduced (2% compared to 18%, p=0.005). During regular clinical care, HbA1c levels for the DiPiS children remained lower both at 12 (0.4% (4 mmol/mol); p=0.009) and 24 months (0.8% (9 mmol/mol) p < 0.001) after diagnosis, despite no difference in total daily insulin between the two groups. Conclusions: Participation in prospective follow-up before diagnosis of type 1 diabetes leads to earlier diagnosis with fewer symptoms, decreased incidence of ketoacidosis as well as better metabolic control up to 2 yr after diagnosis. Our data indicate that metabolic control at the time of diabetes diagnosis is important for early metabolic control possibly affecting the risk of long-term complications.
|
|
| 5. |
|
|
| 6. |
- Andersson, Cecilia K, et al.
(författare)
-
Glucose tolerance and beta-cell function in islet autoantibody-positive children recruited to a secondary prevention study.
- 2013
-
Ingår i: Pediatric Diabetes. - : Hindawi Limited. - 1399-543X .- 1399-5448. ; 14:5, s. 341-349
-
Tidskriftsartikel (refereegranskat)abstract
- AIMS: Children with type 1 diabetes (T1D) risk and islet autoantibodies are recruited to a secondary prevention study. The aims were to determine metabolic control in relation to human leukocyte antigen (HLA) genetic risk and islet autoantibodies in prepubertal children. METHODS: In 47 healthy children with GADA and at least one additional islet autoantibody, intravenous glucose tolerance test (IvGTT) and oral glucose tolerance test (OGTT) were performed 8-65 d apart. Hemoglobin A1c, plasma glucose as well as serum insulin and C-peptide were determined at fasting and during IvGTT and OGTT. RESULTS: All children aged median 5.1 (4.0-9.2) yr had autoantibodies to two to six of the beta-cell antigens GAD65, insulin, IA-2, and the three amino acid position 325 variants of the ZnT8 transporter. In total, 20/47 children showed impaired glucose metabolism. Decreased (≤30 μU/mL insulin) first-phase insulin response (FPIR) was found in 14/20 children while 11/20 had impaired glucose tolerance in the OGTT. Five children had both impaired glucose tolerance and FPIR ≤30 μU/mL insulin. Number and levels of autoantibodies were not associated with glucose metabolism, except for an increased frequency (p = 0.03) and level (p = 0.01) of ZnT8QA in children with impaired glucose metabolism. Among the children with impaired glucose metabolism, 13/20 had HLA-DQ2/8, compared to 9/27 of the children with normal glucose metabolism (p = 0.03). CONCLUSION: Secondary prevention studies in children with islet autoantibodies are complicated by variability in baseline glucose metabolism. Evaluation of metabolic control with both IvGTT and OGTT is critical and should be taken into account before randomization. All currently available autoantibody tests should be analyzed, including ZnT8QA.
|
|
| 7. |
- Antonio Lopez-Lopez, Jose, et al.
(författare)
-
Simple hollow fiber liquid membrane based pre-concentration of silver for atomic absorption spectrometry
- 2014
-
Ingår i: Analytical Methods. - : Royal Society of Chemistry (RSC). - 1759-9660. ; 6:5, s. 1462-1467
-
Tidskriftsartikel (refereegranskat)abstract
- Silver pollution has gained attention in the last few years because silver is being massively used as a bactericide in self-care, medical and textile products. Difficulties of Ag determination are associated with the very low concentrations in which it is normally found (ng L-1) and the nature of the sample matrix. Standard methods such as liquid-liquid extraction (LLE) are regularly used. Alternatively, liquid phase micro-extraction (LPME) appears to be an environmentally friendly tool for sample treatment that offers higher pre-concentration factors. This allows the determination of ultra-trace levels of silver using standard instrumental techniques such as atomic absorption spectrometry. In this work, a hollow fiber LPME is proposed. Silver pre-concentration has been conducted using tri-isobutylphosphine sulphide (TIBPS) as a carrier from the sample to an acceptor solution through a solvent placed in the fiber pores. Accurel-PP 50/280 fibers with an internal volume of 20 mu L were used for 50 mL samples. After optimization, 0.1 M KNO3 in the sample, 0.1 M TIBPS in dihexyl ether as the organic phase and 1 M Na2S2O3 in the acceptor solution were established. The system offers enrichment factors of 1053 times, a limit of detection of 1.16 ng L-1. This method improves the limit of detection of the most recent liquid micro-extraction methods for silver pre-concentration coupled with GFAAS, being in this case comparable to ICP-MS detection based techniques.
|
|
| 8. |
- Barri, Thaer, et al.
(författare)
-
Advances and developments in membrane extraction for gas chromatography: Techniques and applications.
- 2008
-
Ingår i: Journal of Chromatography A. - : Elsevier BV. - 0021-9673. ; 1186:1-2, s. 16-38
-
Tidskriftsartikel (refereegranskat)abstract
- This review article focuses on advances and technical developments of the realm of membrane extraction techniques for the analytes that are (made) amenable to gas chromatographic analysis, and sheds light on the analytical applications to biological and environmental samples. In this review, the state of the art in this growing area of membrane extraction for gas chromatography is presented and several selected examples from our work and that of other groups are discussed. The published articles on the techniques and their applications, found in the scientific literature between the years 2000 and May 2007 and cited in over than 100 references, are perused and commented. A good deal of light will be thrown on the novelty of the techniques, instrumentations and applications. The mentioned techniques are mainly microporous membrane liquid-liquid extraction, extracting syringe, two-phase hollow-fibre-protected liquid-phase microextraction and its modifications, and membrane extraction with sorbent interface and its variants. The merits and demerits of the techniques will be highlighted.
|
|
| 9. |
- Barri, Thaer, et al.
(författare)
-
Characterization of drug-protein binding process by employing equilibrium sampling through hollow-fiber supported liquid membrane and Bjerrum and Scatchard plots.
- 2008
-
Ingår i: Journal of Pharmaceutical and Biomedical Analysis. - : Elsevier BV. - 0731-7085. ; 48:1, s. 49-56
-
Tidskriftsartikel (refereegranskat)abstract
- The technique equilibrium sampling through membrane (ESTM) was extended to measuring the free drug concentration in solutions of drug and protein. Bjerrum and Scatchard plots were employed for characterizing individual drug binding to pure human blood proteins. Four drugs were investigated as a model system: fluvoxamine and ropivacaine which dominantly bind to alpha-acid glycoprotein (AGP), and R,S-ibuprofen and S-ketoprofen which highly bind to human serum albumin (HSA). The level of drug binding to AGP and HSA relied on drug and protein concentrations. Bjerrum and Scatchard plots revealed high affinity constants (K(a)) at low protein concentration. Both Bjerrum and Scatchard plots of fluvoxamine and ropivacaine binding to AGP showed one specific binding site (n(1)=1) with ropivacaine K(a) value close to 5 times higher than the K(a) of fluvoxamine at 22.9muM AGP concentration. Bjerrum plots of ketoprofen and ibuprofen gave total number of binding sites or bound molecules of 6-7, which did not depend on the drug or protein concentration. Scatchard plots of ketoprofen and ibuprofen exhibited two binding sites (n(1) and n(2)) at 0.15muM and 0.75muM HSA concentrations. On one hand, at 0.15muM HSA, ketoprofen and ibuprofen were bound to site I at n(1)=1.2 and n(1)=1.0, respectively. However, at 0.75muM HSA, ketoprofen and ibuprofen were bound to site I at n(1)=1.2 and n(1)=1.9, respectively. On the other hand, site II, at 0.15muM HSA, interacted with ketoprofen and ibuprofen at n(2)=5.6 and 6.7, respectively. However, at 0.75muM HSA, site II interacted with ketoprofen at n(2)=7.4 and ibuprofen at n(2)=6.2. It would be concluded that, upon mixing ketoprofen and ibuprofen in a HSA solution, a ketoprofen-ibuprofen interaction would most likely occur at site II in HSA.
|
|
| 10. |
- Barri, Thaer, et al.
(författare)
-
Extracting Syringe for determination of organochlorine pesticides in leachate water and soil-water slurry: A novel technology for environmental analysis
- 2006
-
Ingår i: Journal of Chromatography A. - : Elsevier BV. - 0021-9673. ; 1111:1, s. 11-20
-
Tidskriftsartikel (refereegranskat)abstract
- The Extracting Syringe (ESy), a novel membrane-based sample preparation technique directly coupled as an autosampler to gas chromatography, has been employed for the analysis of organochlorine pesticides (OCPs) in raw leachate water. The ESy has also been applied for extraction of OCPs from contaminated soil samples and its performance has been compared to liquid-solid extraction (LSE) and accelerated solvent extraction (ASE). Extraction of 3-mL leachate sample at the optimised conditions resulted in enrichment factors from 32 (Endrin aldehyde) to 242 (Endrin) and detection limits from 1 to 20 ng/L. The inter-day and intra-day repeatability (% RSD) at 100 and 500 ng/L were < 6% and < 24%, respectively. The relative recovery at 100 and 500 ng/L ranged from 68% (Aldrin) to 116% (Endrin aldehyde); except Heptachlor that showed 51 and 60%, respectively. The ESy extraction of the slurry-made soil samples revealed occurrence of Endosulfan I (18.2 mu g/g soil), 4,4'-DDE (2.6 ng/g soil), Endosulfan 11 (8.7 mu g/g soil) and Endosulfan sulfate (1.1 mu g/g soil); showing good agreement with LSE results. The total ESy consumption of organic solvents was 4.2 mL from which only 0.6 mL n-undecane was used during the extraction step (7 mu L for the extraction per se), while in the LSE and ASE, it was 420 and 18.1 mL, respectively. The ESy extraction time (0.5 h) was comparable to the ASE time (0.6 h); and the time required for the LSE was 3.75 h. To sum up, the ESy has shown its competency to LSE and ASE technologies, demonstrating its applicability for environmental analysis of organic pollutants, towards green techniques for green environment. (c) 2006 Elsevier B.V. All rights reserved.
|
|
