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13. Effects of bcrp and p-gp modulators on the penetration of aflatoxin b1 into the mouse brain

Author

TRAS B, CETIN G, UNEY K, DIK B, CORUM O, and ATALAY S

Subjects
aflatoxin b1, brain, drug transporter proteins, modulation, mice, Veterinary medicine, SF600-1100
Abstract

This study was conducted to determine whether the plasma and brain concentrations of AFB1 are affected by the modulation of P-gp and BCRP using zosuquidar (ZQR) and prazosin (PRZ), respectively. In this study, a total of 40 healthy adult male BALB/c mice (32±3.7 g) were used. The animals were randomly divided into 5 groups, with 8 animals per group. Group 1 was used for method validation. Group 2 (AF) received intraperitoneal AFB1 at a dose of 20 mg/kg of body weight. Groups 3 (AF+PRZ), 4 (AF+ZQR), and 5 (AF+PRZ+ZQR) received 20 mg/kg of AFB1 intraperitoneally 30 min after the intraperitoneal administration of prazosin (0.3 mg/kg), zosuquidar (25 mg/kg), and prazosin+zosuquidar (0.3 mg/kg prazosin + 25 mg/kg zosuquidar), respectively. Six hours after the administration of AFB1, blood and brain samples were collected from the animals in Groups 2 to 5. AFB1 concentrations were determined using an HPLC system with fluorescence detection. Individual and simultaneous administration of prazosin and zosuquidar significantly reduced the brain concentrations of AFB1 in comparison to a single administration of AFB1 (P

Published
2017
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23. Serum drug levels and anti-drug antibodies in the context of dose tapering by interval prolongation of adalimumab, etanercept and ustekinumab in psoriasis patients: results of the CONDOR trial

Author

Atalay, S., Berends, S.E., Groenewoud, H., Mathot, R.A.A., Njoo, D.M., Mommers, J.M., Ossenkoppele, P.M., Koetsier, M.I., Berends, Matthijs S., Vries, Annick de, Kerkhof, P.C.M. van de, Broeder, A.A. den, Jong, E.M.G.J. de, Reek, J.M.P.A. van den, Atalay, S., Berends, S.E., Groenewoud, H., Mathot, R.A.A., Njoo, D.M., Mommers, J.M., Ossenkoppele, P.M., Koetsier, M.I., Berends, Matthijs S., Vries, Annick de, Kerkhof, P.C.M. van de, Broeder, A.A. den, Jong, E.M.G.J. de, and Reek, J.M.P.A. van den

Abstract

Contains fulltext : 282879.pdf (Publisher’s version ) (Open Access), BACKGROUND: Biologics for psoriasis are registered in standard dosages. In patients with low disease activity, reduction of the dose by interval prolongation can prevent overtreatment, and lower risks and costs. However, fear for increased anti-drug antibody (ADA) formation due to interval prolongation of biologics is an important barrier. OBJECTIVE: To investigate the course of serum drug concentrations, ADA levels, and predictors for successful dose reduction of adalimumab, ustekinumab, and etanercept for psoriasis. METHODS: Patients were randomized to dose reduction (DR) or usual care (UC) and followed for one year. The course and extent of detectable ADA levels were expressed as proportions/relative risks for DR vs. UC. Association of baseline characteristics with successful tapering was investigated with log-binomial regression analysis. RESULTS: In total, 118 patients were included. In adalimumab-treated patients, no significant difference in the proportion of patients with relevant ADA levels in DR vs. UC was seen. For ustekinumab, relevant ADA development was absent in both groups. Baseline trough levels were not predictive for successful DR. CONCLUSIONS: Immunogenicity may not increase by interval prolongation in psoriasis patients with low disease activity. This pilot provides important and reassuring insight into the pharmacological changes after dose tapering of adalimumab, etanercept, and ustekinumab.

Published
2022

25. Two-year follow-up of a dose reduction strategy trial of biologics adalimumab, etanercept, and ustekinumab in psoriasis patients in daily practice

Author

Atalay, S., Reek, J.M.P.A. van den, Groenewoud, J.M.M., Kerkhof, P.C.M. van de, Kievit, W., Jong, E.M.G.J. de, Atalay, S., Reek, J.M.P.A. van den, Groenewoud, J.M.M., Kerkhof, P.C.M. van de, Kievit, W., and Jong, E.M.G.J. de

Abstract

Contains fulltext : 251762.pdf (Publisher’s version ) (Open Access), BACKGROUND/OBJECTIVES: Tightly-controlled dose reduction was possible during 1 year in psoriasis patients on adalimumab, etanercept or ustekinumab with low disease activity (CONDOR trial). Extended observation is needed to ensure long-term effectiveness and safety of the strategy. With prolonged follow-up, we investigated the clinical effects and safety of the strategy, the proportion of patients with successful dose reduction, and assessed if patients with a disease flare regained remission. METHODS: Two-year follow up of a subgroup of patients previously included in a randomized pragmatic study comparing usual care (UC) with stepwise dose reduction (DR). Effectiveness (Psoriasis Area and Severity Index, PASI), Dermatology Life Quality Index (DLQI), adverse events, proportion of patients with successful DR and proportion of persistent disease flares were analyzed. RESULTS: DR leads temporarily to a slightly increased PASI groupwise, but on the long-term patients regained low PASI. DLQI scores remained stable during follow-up. No serious adverse events due to DR were reported. Forty-one percent of patients remained on a low dose up to 2 years. The number of persistent flares was low in DR and UC. CONCLUSIONS: The proposed dose reduction strategy is effective for a significant part of patients and remains safe up to 2 years of follow-up.

Published
2022

26. Frequency and predictors of a high clinical response in patients with psoriasis on biological therapy in daily practice: results from the prospective, multicenter BioCAPTURE cohort

Author

Zweegers, J., Roosenboom, B., van de Kerkhof, P.C.M., van den Reek, J.M.P.A., Otero, M.E., Atalay, S., Kuijpers, A.L.A., Koetsier, M.I.A., Arnold, W.P., Berends, M.A., Weppner‐Parren, L., Bijen, M., Njoo, M.D., Mommers, J.M., van Lümig, P.P.M., Driessen, R.J.B., Kievit, W., and de Jong, E.M.G.J.

Published
2017
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32. Influence of Ti substitution on magnetic and magnetocaloric properties of Pr2Fe17-xTix intermetallic compounds.

Author

Cengiz, N. E., Pektas, M., Kaya, A. O., Bayri, N., Izgi, T., Gencer, H., Kolat, V. S., and Atalay, S.

Subjects
MAGNETIC entropy, MAGNETIC transitions, MAGNETIC properties, INTERMETALLIC compounds, MAGNETIC measurements, CRITICAL exponents, MAGNETIC fields
Abstract

The structural, magnetic, and magnetocaloric properties of the Pr2Fe17-xTix (x = 0, 0.2, 0.4, 0.6) intermetallic compounds prepared by the arc-melting process were investigated. X-ray analyses indicated that all samples are single phase with the rhombohedral Th2Zn17-type structure. The unit-cell volume was determined to increase with the increasing Ti content. The magnetic measurements revealed that the Curie temperature increases with Ti content from 286 K for x = 0 to 337 K for x = 0.6. The maximum value of |ΔSm| tends to decrease from 5.63 J/kg.K for x = 0 to 4.28 J/kg.K for x = 0.6 with increasing Ti content at 5 T magnetic field change. At the same magnetic field change, the relative cooling power (RCP) ranges from 425.17 J/Kg for x = 0 to 385.62 J/Kg for x = 0.6. The critical exponents (β, γ, and δ) determined from magnetocaloric data for x < 0.2 belong to mean-field model with long-range ferromagnetic interaction. A small deviation in the critical exponents of γ and δ for x > 0.4 samples was attributed to inhomogeneous magnetic state of the samples. From the phase analysis, it was concluded that all samples showed a second-order magnetic phase transition. [ABSTRACT FROM AUTHOR]

Published
2023
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41. Dose reduction of biologics in psoriasis

Author

Jong, E.M.G.J. de, Kievit, W., Reek, J.M.P.A. van den, Atalay, S., Jong, E.M.G.J. de, Kievit, W., Reek, J.M.P.A. van den, and Atalay, S.

Abstract

Radboud University, 21 december 2021, Promotor : Jong, E.M.G.J. de Co-promotores : Kievit, W., Reek, J.M.P.A. van den, Contains fulltext : 240236.pdf (Publisher’s version ) (Open Access)

Published
2021

42. Evaluation of a One-step Dose Reduction Strategy of Adalimumab, Etanercept and Ustekinumab in Patients with Psoriasis in Daily Practice

Author

Atalay, S., Schoot, L.S. van der, Vandermaesen, L.M.D., Vugt, L.J. van, Eilander, Mascha, Reek, J.M.P.A. van den, Jong, E.M.G.J. de, Atalay, S., Schoot, L.S. van der, Vandermaesen, L.M.D., Vugt, L.J. van, Eilander, Mascha, Reek, J.M.P.A. van den, and Jong, E.M.G.J. de

Abstract

Contains fulltext : 234405.pdf (Publisher’s version ) (Open Access)

Published
2021

43. Dose reduction of biologics in psoriasis.

Author

Atalay, S. and Atalay, S.

Subjects
Radboud Institute for Health Sciences., Radboudumc 5: Inflammatory diseases., Radboudumc 5: Inflammatory diseases RIHS: Radboud Institute for Health Sciences.
Published
2021

49. Structural, magnetic and magnetocaloric properties of Ru doped Pr0.67Ca0.33Mn1 − xRuxO3 manganites.

Author

Kanıkırmızı, T., İzgi, T., Bayri, N., Gencer, H., Kolat, V. S., Pektas, M., and Atalay, S.

Subjects
MAGNETOCALORIC effects, MAGNETIC properties, MAGNETIC transitions, MANGANESE, CURIE temperature, MAGNETIC moments, MAGNETIZATION measurement
Abstract

We have investigated the influence of ruthenium doping on magnetic and magnetocaloric properties of Pr0.67Ca0.33Mn1 − x RuxO3 (x = 0, 0.05, 0.1, 0.15, 0.2, 0.3, 0.5) compounds. X-ray results revealed that the samples have an orthorhombic structure with Pnma space group. The magnetization analysis also showed that Ru doping destroys CO antiferromagnetic and simultaneously inducing ferromagnetism. Variation of lattice parameters and magnetization measurements revealed the existence of mixed valence states of Ru3+ and Ru4+. With increasing Ru content, a slight increase in Curie temperature and magnetization values was observed until x = 0.15. At further Ru doping rates, a considerable decrease was observed in Curie temperature and saturation magnetization. Such a behavior at high Ru concentration rates in saturation magnetization and Curie temperature was attributed to a smaller magnetic moment of Ru4+ than that of Mn3+ and Mn4+ and increase of AFM interaction between the Ru3+– Mn3+ and Ru3+– Mn4+ pairs. The decrease in |ΔSm| was attributed to the second-order magnetic phase transition and the reduction in saturation magnetization. [ABSTRACT FROM AUTHOR]

Published
2022
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