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- Berger, Michelle L., et al.
(författare)
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Alternative and legacy flame retardants in marine mammals from three northern ocean regions
- 2023
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Ingår i: Environmental Pollution. - 0269-7491 .- 1873-6424. ; 335, s. 122255-122255
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Tidskriftsartikel (refereegranskat)abstract
- Flame retardants are globally distributed contaminants that have been linked to negative health effects in humans and wildlife. As top predators, marine mammals bioaccumulate flame retardants and other contaminants in their tissues which is one of many human-imposed factors threatening population health. While some flame retardants, such as the polybrominated diphenyl ethers (PBDE), have been banned because of known toxicity and environmental persistence, limited data exist on the presence and distribution of current-use alternative flame retardants in marine mammals from many industrialized and remote regions of the world. Therefore, this study measured 44 legacy and alternative flame retardants in nine marine mammal species from three ocean regions: the Northwest Atlantic, the Arctic, and the Baltic allowing for regional, species, age, body condition, temporal, and tissue comparisons to help understand global patterns. PBDE concentrations were 100–1000 times higher than the alternative brominated flame retardants (altBFRs) and Dechloranes. 2,2′,4,5,5′-pentabromobiphenyl (BB-101) and hexabromobenzene (HBBZ) were the predominant altBFRs, while Dechlorane-602 was the predominant Dechlorane. This manuscript also reports only the second detection of hexachlorocyclopentadienyl-dibromocyclooctane (HCDBCO) in marine mammals. The NW Atlantic had the highest PBDE concentrations followed by the Baltic and Arctic which reflects greater historical use of PBDEs in North America compared to Europe and greater industrialization of North America and Baltic countries compared to the Arctic. Regional patterns for other compounds were more complicated, and there were significant interactions among species, regions, body condition and age class. Lipid-normalized PBDE concentrations in harbor seal liver and blubber were similar, but HBBZ and many Dechloranes had higher concentrations in liver, indicating factors other than lipid dynamics affect the distribution of these compounds. The health implications of contamination by this mixture of compounds are of concern and require further research.
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- Kip, A E, et al.
(författare)
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Validation and clinical evaluation of a novel method to measure miltefosine in leishmaniasis patients using dried blood spot sample collection
- 2016
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Ingår i: Antimicrobial Agents and Chemotherapy. - 0066-4804 .- 1098-6596. ; 60:4, s. 2081-2089
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Tidskriftsartikel (refereegranskat)abstract
- To facilitate future pharmacokinetic studies of combination treatments against leishmaniasis in remote endemic regions, a simple and cheap sampling methodology was required for miltefosine quantification. The aim of this study was to validate a liquid chromatography-tandem mass spectrometry method to quantify miltefosine in dried blood spots (DBS) and to validate its use in Ethiopian visceral leishmaniasis (VL) patients. Since hematocrit (Ht) values are typically severely decreased in VL patients, regressing to normal during treatment, the method was evaluated over a range of clinically relevant Ht values.Miltefosine was extracted from DBS using a simple pre-treatment method with methanol, resulting in >97% recovery. The method was validated over a calibration range of 10-2,000 ng/mL and accuracy and precision were within ±11.2% and ≤7.0% (≤19.1% at LLOQ), respectively. The method was accurate and precise for blood spot volumes between 10-30 μL and for an Ht of 20-35%, though a linear effect of Ht on miltefosine quantification was observed in the bioanalytical validation. DBS samples were stable for at least 162 days at 37°C.Clinical validation of the method using paired DBS and plasma samples from 16 VL patients showed a median observed DBS:plasma miltefosine concentration ratio of 0.99, with good correlation (Pearson's r=0.946). Correcting for patient-specific Ht did not further improve the concordance between the sampling methods.This successfully validated method to quantify miltefosine in DBS was demonstrated to be a valid and practical alternative to venous blood sampling which can be applied in future miltefosine pharmacokinetic studies in leishmaniasis patients, without Ht-correction.
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- Molenaar-Kuijsten, Laura, et al.
(författare)
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Everolimus Concentration in Saliva to Predict Stomatitis : A Feasibility Study in Patients with Cancer.
- 2022
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Ingår i: Therapeutic Drug Monitoring. - : Ovid Technologies (Wolters Kluwer Health). - 0163-4356 .- 1536-3694. ; 44:4, s. 520-526
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Most patients with cancer treated with everolimus experience stomatitis, which seriously affects the quality of life. The salivary concentrations of everolimus may predict the incidence and severity of stomatitis. The authors aimed to examine whether it was feasible to quantify the everolimus concentration in saliva and subsequently use it to predict stomatitis.METHODS: Saliva and whole blood samples were taken from patients with cancer, who were treated with everolimus in the dosage of either 10 mg once a day or 5 mg twice a day. Everolimus concentrations in saliva samples were measured by liquid chromatography-tandem mass spectrometry. A published population pharmacokinetic model was extended with the everolimus concentration in saliva to assess any association between everolimus in the blood and saliva. Subsequently, the association between the occurrence of stomatitis and the everolimus concentration in saliva was studied.RESULTS: Eleven patients were included in this study; saliva samples were available from 10 patients, including 3 patients with low-grade stomatitis. Everolimus concentrations were more than 100-fold lower in saliva than in whole blood (accumulation ratio 0.00801 and relative standard error 32.5%). Interindividual variability (67.7%) and residual unexplained variability (84.0%) were high. The salivary concentration of everolimus tended to be higher in patients with stomatitis, 1 hour postdose ( P = 0.14).CONCLUSIONS: Quantification of the everolimus concentration in saliva was feasible and revealed a nonsignificant correlation between everolimus concentration in the saliva and the occurrence of stomatitis. If future research proves this relationship to be significant, the everolimus concentration in the saliva may be used as an early predictor of stomatitis without invasive sampling. Thereby, in patients with high salivary everolimus concentrations, precautions can be taken to decrease the incidence and severity of stomatitis.
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- Roseboom, Ignace C, et al.
(författare)
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Development and validation of an HPLC-MS/MS method for the quantification of the anti-leishmanial drug miltefosine in human skin tissue.
- 2022
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Ingår i: Journal of Pharmaceutical and Biomedical Analysis. - : Elsevier BV. - 0731-7085 .- 1873-264X. ; 207, s. 114402-
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Tidskriftsartikel (refereegranskat)abstract
- Miltefosine is the only oral drug approved for the treatment of various clinical presentations of the neglected parasitic disease leishmaniasis. In cutaneous leishmaniasis and post-kala-azar dermal leishmaniasis, Leishmania parasites reside and multiply in the dermis of the skin. As miltefosine is orally administered and this drug is currently studied for the treatment of these skin-related types of leishmaniasis, there is an urgent need for an accurate assay to determine actual miltefosine levels in human skin tissue to further optimize treatment regimens through target-site pharmacokinetic studies. We describe here the development and validation of a sensitive method to quantify miltefosine in 4-mm human skin biopsies utilizing high-performance liquid chromatography coupled to tandem mass spectrometry. After the skin tissues were homogenized overnight by enzymatic digestion using collagenase A, the skin homogenates were further processed by protein precipitation and phenyl-bonded solid phase extraction. Final extracts were injected onto a Gemini C18 column using alkaline eluent for separation and elution. Detection was performed by positive ion electrospray ionization followed by a quadrupole - linear ion trap mass spectrometer, using deuterated miltefosine as an internal standard. The method was validated over a linear calibration range of 4-1000 ng/mL (r2 ≥ 0.9996) using miltefosine spiked digestion solution for calibration and quality control samples. Validation parameters were all within internationally accepted criteria, including intra- and inter-assay accuracies and precisions within± 15% and ≤ 15% (within± 20% and ≤ 20% at the lower limit of quantitation). There was no significant matrix effect of the human skin tissue matrix and the recovery for miltefosine, and internal standard were comparable. Miltefosine in human skin tissue homogenates was stable during the homogenization incubation (37 °C,± 16 h) and after a minimum of 10 days of storage at - 20 °C after the homogenization process. With our assay we could successfully detect miltefosine in skin biopsies from patients with post-kala azar dermal leishmaniasis who were treated with this drug in Bangladesh.
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