| 1. |
- Barri, Thaer, et al.
(författare)
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Extracting Syringe for determination of organochlorine pesticides in leachate water and soil-water slurry: A novel technology for environmental analysis
- 2006
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Ingår i: Journal of Chromatography A. - : Elsevier BV. - 0021-9673. ; 1111:1, s. 11-20
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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.
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| 2. |
- Bergström, Staffan, et al.
(författare)
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Extracting syringe for extraction of phthalate esters in aqueous environmental samples
- 2007
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Ingår i: Analytica Chimica Acta. - : Elsevier BV. - 1873-4324 .- 0003-2670. ; 594:2, s. 240-247
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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%).
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| 3. |
- Liljeqvist, Jan-Åke, 1954, et al.
(författare)
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Asymptomatically shed recombinant herpes simplex virus type 1 strains detected in saliva
- 2009
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Ingår i: Journal of General Virology. - : Microbiology Society. - 0022-1317 .- 1465-2099. ; 90:Pt 3, s. 559-66
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Tidskriftsartikel (refereegranskat)abstract
- Herpes simplex virus type 1 (HSV-1) is a ubiquitous pathogen infecting most individuals worldwide. The majority of HSV-1-infected individuals have no clinical symptoms but shed HSV-1 asymptomatically in saliva. Recent phylogenetic analyses of HSV-1 have defined three genetic clades (A-C) and recombinants thereof. These data have all been based on clinical HSV-1 isolates and do not cover genetic variation of asymptomatically shed HSV-1. The primary goal of this study was to investigate such variation. A total of 648 consecutive saliva samples from five HSV-1-infected volunteers was collected. Asymptomatic shedding was detected on 7.6 % of the days from four subjects. The HSV-1 genome loads were quantified with real-time PCR and varied from 1x10(2) to 2.8x10(6) copies of virus DNA (ml saliva)(-1). Phylogenetic network analyses and bootscanning were performed on asymptomatically shed HSV-1. The analyses were based on DNA sequencing of the glycoprotein I gene, and also of the glycoprotein E gene for putative recombinants. For two individuals with clinical HSV-1 infection, the same HSV-1 strain was shed asymptomatically as induced clinical lesions, and sequence analyses revealed that these strains clustered distinctly to clades A and B, respectively. For one of the subjects with no clinical HSV-1 infection, a recombinant strain was identified. The other truly asymptomatic individual shed evolutionarily distinct HSV-1 strains on two occasions. The first strain was classified as a recombinant and the other strain clustered in clade A. High replication rates of different strains in the same person may facilitate the creation of recombinant clinical HSV-1 strains.
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| 4. |
- Norberg, Peter, 1974, et al.
(författare)
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Complete-genome phylogenetic approach to varicella-zoster virus evolution: genetic divergence and evidence for recombination.
- 2006
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Ingår i: Journal of virology. - 0022-538X. ; 80:19, s. 9569-76
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Tidskriftsartikel (refereegranskat)abstract
- Recent studies of varicella-zoster virus (VZV) DNA sequence variation, involving large numbers of globally distributed clinical isolates, suggest that this virus has diverged into at least three distinct genotypes designated European (E), Japanese (J), and mosaic (M). In the present study, we determined and analyzed the complete genomic sequences of two M VZV strains and compared them to the sequences of three E strains and two J strains retrieved from GenBank (including the Oka vaccine preparation, V-Oka). Except for a few polymorphic tandem repeat regions, the whole genome, representing approximately 125,000 nucleotides, is highly conserved, presenting a genetic similarity between the E and J genotypes of approximately 99.85%. These analyses revealed that VZV strains distinctly segregate into at least four genotypes (E, J, M1, and M2) in phylogenetic trees supported by high bootstrap values. Separate analyses of informative sites revealed that the tree topology was dependent on the region of the VZV genome used to determine the phylogeny; collectively, these results indicate the observed strain variation is likely to have resulted, at least in part, from interstrain recombination. Recombination analyses suggest that strains belonging to the M1 and M2 genotypes are mosaic recombinant strains that originated from ancestral isolates belonging to the E and J genotypes through recombination on multiple occasions. Furthermore, evidence of more recent recombination events between M1 and M2 strains is present in six segments of the VZV genome. As such, interstrain recombination in dually infected cells seems to figure prominently in the evolutionary history of VZV, a feature it has in common with other herpesviruses. In addition, we report here six novel genomic targets located in open reading frames 51 to 58 suitable for genotyping of clinical VZV isolates.
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| 5. |
- Norberg, Peter, 1974, et al.
(författare)
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Divergence and recombination of clinical herpes simplex virus type 2 isolates.
- 2007
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Ingår i: Journal of virology. - 1098-5514. ; 81:23, s. 13158-67
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Forskningsöversikt (refereegranskat)abstract
- Herpes simplex virus type 2 (HSV-2) infects the genital mucosa and is one of the most common sexually transmitted viruses. Here we sequenced a segment comprising 3.5% of the HSV-2 genome, including genes coding for glycoproteins G, I, and E, from 27 clinical isolates from Tanzania, 10 isolates from Norway, and 10 isolates from Sweden. The sequence variation was low compared to that described for clinical HSV-1 isolates, with an overall similarity of 99.6% between the two most distant HSV-2 isolates. Phylogenetic analysis revealed a divergence into at least two genogroups arbitrarily designated A and B, supported by high bootstrap values and evolutionarily separated at the root. Genogroup A contained isolates collected in Tanzania, and genogroup B contained isolates collected in Tanzania and Scandinavia, implying that the genetic variability of HSV-2 is higher in Tanzania than in Scandinavia. Recombination network analysis and bootscan analysis revealed a complex pattern of phylogenetically conflicting informative sites in the sequence alignments. These signals were present in synonymous and nonsynonymous sites in all three genes and were not accumulated in specific regions, observations arguing against positive selection. Since the PHI test applied solely to synonymous sites revealed a high statistical probability of recombination, we suggest as a novel finding that homologous recombination is, as reported earlier for HSV-1 and varicella-zoster virus, a prominent feature in the evolution of HSV-2.
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| 6. |
- Norberg, Peter, 1974, et al.
(författare)
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Genotyping of clinical herpes simplex virus type 1 isolates by use of restriction enzymes.
- 2006
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Ingår i: Journal of clinical microbiology. - 0095-1137. ; 44:12, s. 4511-4
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Tidskriftsartikel (refereegranskat)abstract
- Recently, three distinct genotypes of clinical herpes simplex virus type 1 (HSV-1) isolates were identified based on DNA sequence information and phylogenetic analysis of clinical isolates and laboratory strains. We utilized single-nucleotide polymorphism within the genes coding for glycoproteins G and I for rapid genotype classification by PCR and restriction enzyme cleavage. The method is suitable for high-scale genotyping of clinical HSV-1 isolates and for the detection of recombinants.
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| 7. |
- Norberg, Peter, 1974, et al.
(författare)
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Glycoprotein I of herpes simplex virus type 1 contains a unique polymorphic tandem-repeated mucin region.
- 2007
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Ingår i: The Journal of general virology. - : Microbiology Society. - 0022-1317 .- 1465-2099. ; 88:Pt 6, s. 1683-8
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Forskningsöversikt (refereegranskat)abstract
- Glycoprotein I (gI) of herpes simplex virus type 1 (HSV-1) contains a tandem repeat (TR) region including the amino acids serine and threonine, residues that can be utilized for O-glycosylation. The length of this TR region was determined for 82 clinical HSV-1 isolates and the results revealed a polymorphic distribution of two to six or eight repeated blocks with a majority harbouring between two and four repeats. Assessment of the O-glycosylation capacity of an acceptor peptide (STPSTTTSTPSTTT), representing two of the gI blocks, showed that the peptide was a universal substrate for O-glycosylation not only for the two most commonly expressed N-acetyl-d-galactosamine (GalNAc)-T1 and -T2 transferases, but also for the GalNAc-T3, -T4 and -T11 transferases. Immunoblotting of virus-infected cells showed that gI was exclusively O-glycosylated with GalNAc monosaccharides (Tn antigen). A polymorphic mucin region has not been described previously for HSV-1 and is a unique finding, as repeated blocks within gI homologues are lacking in other alphaherpesviruses.
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| 8. |
- Norberg, Åke, et al.
(författare)
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Population volume kinetics predicts retention of 0.9% saline infused in awake and isoflurane-anesthetized volunteers
- 2007
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Ingår i: Anesthesiology. - : Lippincott Williams & Wilkins. - 0003-3022 .- 1528-1175. ; 107:1, s. 24-32
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: In previous work, extravascular expansion was observed to be enhanced by isoflurane anesthesia in sheep when a crystalloid bolus was administered. The aim of the current study was to further elaborate these investigations to humans and to explore the use of population kinetics in the analysis of fluid shifts.METHODS: Eleven healthy volunteers participated in two experiments each, either awake or isoflurane anesthetized, during which they received 25 ml/kg saline, 0.9%, intravenously over 20 min. Plasma dilution data were derived from repeated sampling of hemoglobin concentration, and population pharmacokinetic analysis was conducted using the WinNonMix 2.0.1 software (Pharsight Corporation, Mountain View, CA). Plasma hormones were measured, and hemodynamic values were monitored.RESULTS: Fluid infusion during isoflurane anesthesia was followed by a higher cardiac output, lower arterial pressure, and lower urinary excretion as compared with the awake protocol (P < 0.05). Albumin dilution was greater than hemoglobin concentration-derived plasma dilution, which indicates a transcapillary leak of albumin. A two-compartment model with an isoflurane-depressed, intercompartmental distribution parameter predicted that more than 50% of the infused volume was retained in the peripheral compartment at 180 min in both protocols. Isoflurane markedly increased the plasma levels of renin and aldosterone, whereas vasopressin was mostly unchanged.CONCLUSION: Fluid retention after rapid infusion of 0.9% saline was prominent in both awake and isoflurane-anesthetized subjects. Altered kinetics of infused 0.9% saline during isoflurane anesthesia was expressed as reduced clearance and a slower distribution, resulting in a small but significant increase in fluid accumulation in the body fluid compartments. These changes may be due to the associated decreasing of mean arterial pressure and increased release of renin and aldosterone.
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| 9. |
- Norberg, Åke, et al.
(författare)
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Volume turnover kinetics of fluid shifts after hemorrhage, fluid infusion, and the combination of hemorrhage and fluid infusion in sheep
- 2005
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Ingår i: Anesthesiology. - : Lippincott Williams & Wilkins. - 0003-3022 .- 1528-1175. ; 102:5, s. 985-994
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Hemorrhage is commonly treated with intravenous infusion of crystalloids. However, the dynamics of fluid shifts between body fluid spaces are not completely known, causing contradictory recommendations regarding timing and volume of fluid infusions. The authors have developed a turnover model that characterizes these fluid shifts.METHODS: Conscious, chronically instrumented sheep (n = 12) were randomly assigned to three protocol groups: infusion of 25 ml/kg of 0.9% saline over 20 min (infusion only), hemorrhage of 300 ml (7.8 +/- 1.1 ml/kg) over 5 min (hemorrhage only), and hemorrhage of 300 ml over 5 min followed by infusion as noted above (hemorrhage plus infusion). A two-compartment volume turnover kinetic model containing seven model parameters was fitted to data obtained by repeated sampling of hemoglobin concentration and urinary excretion.RESULTS: The volume turnover model successfully predicted fluid shifts. Mean baseline volumes of the central and tissue compartments were 1799 +/- 1276 ml and 7653 +/- 5478 ml, respectively. Immediate fluid infusion failed to prevent hemorrhage-induced depression of cardiac output and diuresis. The model suggested that volume recruitment to the central compartment after hemorrhage was primarily achieved by mechanisms other than volume equilibration between the two model compartments.CONCLUSION: Volume turnover kinetics is a promising tool for explaining fluid shifts between body compartments after perturbations such as hemorrhage and intravenous fluid infusions. The pronounced inhibition of renal output after hemorrhage prevailed regardless of fluid infusion and caused fluid retention, which expanded the tissue compartment.
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