| 1. |
- Aimonen, Kukka, et al.
(author)
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Role of Surface Chemistry in the In Vitro Lung Response to Nanofibrillated Cellulose
- 2021
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In: Nanomaterials. - : MDPI. - 2079-4991. ; 11:2
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Journal article (peer-reviewed)abstract
- Wood-derived nanofibrillated cellulose (NFC) has emerged as a sustainable material with a wide range of applications and increasing presence in the market. Surface charges are introduced during the preparation of NFC to facilitate the defibrillation process, which may also alter the toxicological properties of NFC. In the present study, we examined the in vitro toxicity of NFCs with five surface chemistries: nonfunctionalized, carboxymethylated, phosphorylated, sulfoethylated, and hydroxypropyltrimethylammonium-substituted. The NFC samples were characterized for surface functional group density, surface charge, and fiber morphology. Fibril aggregates predominated in the nonfunctionalized NFC, while individual nanofibrils were observed in the functionalized NFCs. Differences in surface group density among the functionalized NFCs were reflected in the fiber thickness of these samples. In human bronchial epithelial (BEAS-2B) cells, all NFCs showed low cytotoxicity (CellTiter-GloVR luminescent cell viability assay) which never exceeded 10% at any exposure time. None of the NFCs induced genotoxic effects, as evaluated by the alkaline comet assay and the cytokinesis-block micronucleus assay. The nonfunctionalized and carboxymethylated NFCs were able to increase intracellular reactive oxygen species (ROS) formation (chloromethyl derivative of 2 ',7 '-dichlorodihydrofluorescein diacetate assay). However, ROS induction did not result in increased DNA or chromosome damage.
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| 2. |
- Suhonen, Satu, et al.
(author)
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Clinical performance of a levonorgestrel-releasing intrauterine system and oral contraceptives in young nulliparous women : A comparative study
- 2004
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In: Contraception. - : Elsevier BV. - 0010-7824 .- 1879-0518. ; 69:5, s. 407-412
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Journal article (peer-reviewed)abstract
- This 1-year randomized study was carried out at family-planning clinics of two university hospitals to compare the safety and acceptability of a levonorgestrel-releasing intrauterine system (LNG IUS) and oral contraceptives (OCs) in young nulliparous women. The study population consisted of 200 women aged 18-25 years seeking contraception. Ninety-four women entered the LNG IUS group and 99 entered the OC group. Continuation rates, reasons leading to discontinuation, adverse events, menstrual questionnaires, subjective well-being and sexual behavior were evaluated. Nineteen women (20%) in the LNG IUS group discontinued the study during the 1-year observation period, and 27 discontinued (27%) in the OC group. The most common reason (31%) for discontinuation in the IUS group was pain. In the OC group, hormonal side effects were the predominant medical reason for study termination. The safety and acceptability of the LNG IUS for contraception was observed to be as good as with OCs, with a high continuation rate.
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