| 1. |
- Dizdar (Dizdar Segrell), Nil, et al.
(författare)
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Letter: Untitled
- 2013
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Ingår i: Journal of Neuroscience Methods. - : Elsevier. - 0165-0270 .- 1872-678X. ; 212:2, s. 363-363
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Tidskriftsartikel (refereegranskat)abstract
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| 2. |
- Jackmann, Natalja, 1968-, et al.
(författare)
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Vitamin D status in children with leukemia, its predictors, and association with outcome
- 2020
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Ingår i: Pediatric Blood & Cancer. - : Wiley. - 1545-5009 .- 1545-5017. ; 67:4, s. e28163-
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Children and adolescents with leukemia are potentially at high risk of vitamin D inadequacy, which may have clinical relevance for skeletal morbidity, infections, and cancer outcome. This study aimed to evaluate vitamin D status at the time of diagnosis to investigate its predictors and association with overall survival in children with leukemia. PROCEDURE: We included all 295 children and adolescents diagnosed with leukemia at our institution between 1990 and 2016 who had available serum sample from the time of diagnosis. We analyzed serum 25-hydroxyvitamin D and parathyroid hormone levels and correlated them with clinical data. RESULTS: The 25-hydroxyvitamin D level was deficient (< 25 nmol/L), insufficient (25-50 nmol/L), sufficient (50-75 nmol/L), and optimal (> 75 nmol/L) in 6.4%, 26.8%, 39.7%, and 27.1% of the children, respectively. Older age and a more recent time of sampling (calendar year) predicted lower 25-hydroxyvitamin D level. In preschool children (age 6 years), the 25-hydroxyvitamin D level showed significant seasonal variation. CONCLUSION: It remains unclear whether vitamin D supplementation in pediatric leukemia patients will improve outcome.
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| 3. |
- Karlsson, Anna, et al.
(författare)
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Degradation of aromatic compounds by micro-organisms in solid waste samples from landfills and landfill simulation reactors
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- The ability by micro-organisms developed in landfilled waste totransform phenol, dimethyl phthalate (DMP), aniline, tetrabromophthalic acid (TBPA), 3-chlorobenzoate (CB) and 2,4,6-trichlorophenol (TCP) was investigated using a method modified after ISO 17334. Forty-four solid waste samples from landfills and landfill simulation reactors (LSRs) were used. The LSRs were run over a five-year period and simulated acid and methanogenic landfill conditions. The biodegradability of each aromatic compound (0.5-0. 7 mM) was assayed over 100-200 days. The degradation capacity was monitored both by quantification of the aromatic compounds and by methane analysis The degradation capacity for the halogenated aromatics was poor or completely lacking by the landfill inocula investigated showing that this kind of compounds might persist in landfill. TCP inhibited both the methanogenic and fermentative micro-flora present in the waste samples, however, in early LSR assays no inhibition was observed. Phenol and DMP was transformed to non aromatic products in most assays. The biodegradation capacity towards these compounds increased over time in the LSR studies i.e. the acid and early methanogenic land fill phases had no or poor degradation capacity. These results indicates that the earlymethanogcnic tlora developing in landfills and landfill simulation reactors is different from the one later established by being less efficient in transformation of aromatic compounds but also less sensitive to aryl halides.
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| 4. |
- Karlsson, Anna, 1969-, et al.
(författare)
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Degradation of phenol under meso- and thermophilic, anaerobic conditions
- 1998
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Ingår i: Anaerobe. - : Elsevier BV. - 1075-9964 .- 1095-8274. ; 5:1, s. 25-35
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Tidskriftsartikel (refereegranskat)abstract
- Based on the results of preliminary studies on phenol degradation under mesophilic conditions with a mixed methanogenic culture, we proposed a degradation pathway in which phenol is fermented to acetate: Part of the phenol is reductively transformed to benzoate while the rest is oxidised, forming acetate as end product. According to our calculations, this should result in three moles of phenol being converted to two moles of benzoate and three moles of acetate (3phenol+2CO2+3H2O→3acetate+2benzoate): To assess the validity of our hypothesis concerning the metabolic pathway, we studied the transformation of phenol under mesophilic and thermophilic conditions in relation to the availability of hydrogen. Hence, methanogenic meso- and thermophilic cultures amended with phenol were run with or without an added over-pressure of hydrogen under methanogenic and non-methanogenic conditions. Bromoethanesulfonic acid (BES) was used to inhibit methanogenic activity. In the mesophilic treatments amended with only BES, about 70% of the carbon in the products found was benzoate. During the course of phenol transformation in these BES-amended cultures, the formation pattern of the degradation products changed: Initially nearly 90% of the carbon from phenol degradation was recovered as benzoate, whereas later in the incubation, in addition to benzoate formation, the aromatic nucleus degraded completely to acetate. Thus, the initial reduction of phenol to benzoate resulted in a lowering of H2levels, giving rise to conditions allowing the degradation of phenol to acetate as the end product. Product formation in bottles amended with BES and phenol occurred in accordance with the hypothesised pathway; however, the overall results indicate that the degradation of phenol in this system is more complex. During phenol transformation under thermophilic conditions, no benzoate was observed and no phenol was transformed in the BES-amended cultures. This suggests that the sensitivity of phenol transformation to an elevated partial pressure of H2is higher under thermophilic conditions than under mesophilic ones. The lack of benzoate formation could have been due to a high turnover of benzoate or to a difference in the phenol degradation pathway between the thermophilic and mesophilic cultures.
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| 5. |
- Karlsson, Anna, et al.
(författare)
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Reduction of phenol to benzoate : an electron sink reaction used by a highly enriched anaerobic culture
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- A non-methanogenic pasteurised enrichment culture fermenting phenolto benzoate, butyrate and acetate was studied, focusing on the effects of adding yeast extract (0.1, 0.2 or I g!l) or glucose (1.5 mM) together with the phenol (5 mM). The results showed that the reductive formation of benzoate from phenol increased when either yeast extract (1 g 1-') or glucose was added to the medium. The culture also transformed phenol at a higher rate when glucose was added as a "co-substrate" than when it was grown on phenol alone. Furthermore, higher growth rates occurred in cultures grown on both substrates rather than on glucose or phenol alone.
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| 6. |
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| 7. |
- Kågedal, Bertil, 1943-, et al.
(författare)
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Determination of glomerular filtration rate, a spin off aftercontrast-enhanced computed tomography among criticallyill patients − proof of concept
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Background Recently, Gong et al. (Gong et al. 2022) showed, in nine heathy subjects, that plasma clearance of high doses of iohexol given as contrast enhanced computed tomography (CT) could be used for determination of glomerular filtration rate (GFR). We utilized high doses of iohexol from angiographic or other contrast enhanced CT given to critical ill patients for calculation of GFRiohexol and compared these data with standard low dose iohexol GFR determinations.Method Patients at intensive care units (ICUs) in Southeast Sweden intended for radiographic investigations that included injection of 45-120 ml of iohexol (Omnipaque) were included, and the concentration of iohexol in plasma was measured by HPLC. Iohexol clearance was calculated by the method of Bröchner-Mortensen. The following days was iohexol clearance determined using the standard low dose of 5 mL of iohexol. Sixteen patients admitted to ICUs were included in this pilot study.Results GFR after high dosing of iohexol at contrast enhanced CT could be measured for all sixteen critically ill patients. Patients with normal or increased renal function had neglectable iohexol concentrations the day following the CT scan. There was excellent correlation between GFR determination with high and standard low iohexol dosing among these 6 patients. Ten patients had decreased renal function and delayed elimination of iohexol, thus was not GFR measurement with low dose iohexol possible to analyse the day after CT scan with high dose iohexol.Conclusion This pilot study showed that GFR can be measured after high doses of iohexol at enhanced CT and compare well with the standard low dose of iohexol clearance determinations.
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| 8. |
- Nezirevic Dernroth, Dzeneta, 1969-, et al.
(författare)
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Gas chromatography-mass spectrometry analysis of pheomelanin degradation products
- 2009
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Ingår i: Journal of Chromatography A. - : Elsevier BV. - 0021-9673 .- 1873-3778. ; 1216:30, s. 5730-5739
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Tidskriftsartikel (refereegranskat)abstract
- Melanoma is most rapidly increasing in the white population and people with pheomelanin skin type are at high risk to develop melanoma. However, little is known about the pheomelanin structure and function, and further elucidation of this melanin is therefore an important task. A GC/MS method was developed based on hydriodic acid hydrolysis of pheomelanin in the urine. Derivatization was performed with ethyl chloroformate and ethanol:pyridine (4:1, v/v). N,O-Ethoxycarbonyl-ethyl esters were extracted with chloroform and analyzed by GC/MS. 4-Amino-3-hydroxyphenylaianine and 3-amino4-hydroxyphenylaianine together with one benzothiazinone and two benzothiazole compounds were detected and identified in hydrolyzed samples of synthetic pheomelanin and melanin from the urine of a patient with melanoma. These findings strongly suggest that heterocyclic pheomelanin-type units are incorporated in the pigment structures.
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| 9. |
- Nezirevic Dernroth, Dzeneta, 1969-, et al.
(författare)
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Hydrophilic interaction liquid chromatographic analysis of aminohydroxyphenylalanines from melanin pigments
- 2007
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Ingår i: Journal of Chromatography A. - : Elsevier BV. - 0021-9673 .- 1873-3778. ; 1163:1-2, s. 70-79
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Tidskriftsartikel (refereegranskat)abstract
- Malignant melanomas are more often seen in subjects with light colored skin who tan poorly than in persons who tan more rapidly. This has been attributed to the structure of their pigment, pheomelanin, which differs markedly from the eumelanin of persons with darker skin. To study the hydrolysis products of pheomelanin pigments a new method was developed for analysis of 4-amino-3-hydroxyphenylalanine (4-AHP) and 3-amino-4-hydroxyphenylalanine (3-AHP). Pheomelanin samples were hydrolyzed and extracted with solid-phase extraction columns using strong cation-exchange (SCX) cartridges. Separation of 4-AHP and 3-AHP was achieved on a ZIC-HILIC column (150 mm × 2.1 mm I.D.) with a mobile phase consisting of acetonitrile:0.1 M ammonium acetate buffer, pH 4.5 (82:18, v/v). Detection was performed with an electrochemical detector at +400 mV. Run time was 30 min. The limits of detection were 73 pg and 51 pg for 4-AHP and 3-AHP respectively, using 2 μl injections. Good linearity was found within the range 0.05-5.0 μg/ml. Absolute recovery was 70% and relative recovery was 100%. The AHPs were stable for 1 year in the hydrolyzed samples, for 4 days in the eluates from solid-phase sorbents stored in the refrigerator, and for 2 days diluted with mobile phase and stored in the autosampler at 10 °C. The within-day imprecision was <5% and the between-day imprecision was <7% for the two analytes. The method, applied to the analysis of pheomelanin in urine from human melanoma patients, allows the analysis of 30 samples in one set and is suitable for routine work with human hair and melanoma cells. By using the ZIC-HILIC stationary phase, ion-pairing reagents could be avoided, which makes the method suitable to further analysis of degradation products from pheomelanins using mass spectrometric detection. © 2007 Elsevier B.V. All rights reserved.
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| 10. |
- Nezirevic Dernroth, Dzeneta, 1969-
(författare)
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Pheomelanin markers in melanoma with reference to their excretion into urine
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Skin pigmentation is an important issue in most cultures. Until recently we have not understood the most important elements of pigmentation regarding detailed chemical structure. The synthesis of melanin is very complex, and although core enzymes, other important proteins, and parts of the melanin structure have been identified much information in this context awaits disclosure.The function of the melanocyte and the deposition of melanin pigments into the keratinocytes are very important in the protection against UV light. Melanin pigments consist of high-molecular structures often described as brown to black eumelanin and yellow to red pheomelanin. Eumelanin is photoprotective, whereas pheomelanin is believed to be carcinogenic after UV radiation. There is strong evidence that people of fair complexion with freckles who tan poorly are at higher risk of developing melanoma. These people have a higher pheomelanin to eumelanin ratio in their skin.Melanoma, one of the most widely spread cancers, is derived from melanocytes. There is accumulating evidence that pigment constitution is highly involved in the development of melanoma. We found that patients with advanced melanoma secrete substantial amounts of pigment structures into the urine, in particular those with diffuse melanosis. In subsequently performed experiments we purified these pigments and subjected the product to chemical degradation by either hydrogen peroxide oxidation or hydriodic hydrolysis. Several new chromatographic methods were developed for the structural analysis of these products. Structural analysis of new chromatographic peaks was performed. In conclusion, complex pheomelanin structures as well as low molecular weight pigments and free benzothiazoles have been identified in the urine of patients with melanoma and diffuse melanosis.The present thesis provides new insight into melanogenesis and melanoma progression. This opens the doorway to further approaches to the investigation of melanins and can help to understand fundamental problems about the structure and biosynthesis of natural melanins.
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