Nanocomposites from a polyester-type water-borne polyurethane (PU) containing different amounts (17.4-174 ppm) of gold (Au) nanoparticles (approximately 5 nm) were prepared. A previous study has shown that the Au nanoparticles could induce surface morphological transformations in the PU (e.g. the mesophase transition from hard lamellae to soft micelles), which modify the physicochemical properties of the PU as well as the fibroblast response to the PU. The current study focused on the biostability and biocompatibility of the nanocomposites. The nanocomposites were characterized by transmission electron microscopy and X-ray photoelectron spectroscopy, and their oxidative stability and free radical scavenging ability were tested. The inflammatory response was evaluated by monocyte activation in vitro and rat subcutaneous implantation in vivo. It was found that the nanocomposites containing 43.5-65 ppm of Au had the least monocyte activation and tissue reactions. PU and the nanocomposites were rather resistant to oxidative degradation in vitro and biodegradation in vivo. The nanocomposites exhibited greater free radical scavenging abilities than the original PU. Based on the above results, the significantly enhanced biocompatibility of the PU-Au nanocomposites with 43.5-65 ppm of gold over the original PU appeared to be a result of the extensively modified surface morphology and greater free radical scavenging ability, instead of due to the difference in biostability.
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http://dx.doi.org/10.1016/j.actbio.2008.06.015 | DOI Listing |
Proc Natl Acad Sci U S A
January 2025
California Institute for Quantitative Biosciences, University of California, Berkeley, CA 94720.
Polysaccharide monooxygenase (PMO) catalysis involves the chemically difficult hydroxylation of unactivated C-H bonds in carbohydrates. The reaction requires reducing equivalents and will utilize either oxygen or hydrogen peroxide as a cosubstrate. Two key mechanistic questions are addressed here: 1) How does the enzyme regulate the timely and tightly controlled electron delivery to the mononuclear copper active site, especially when bound substrate occludes the active site? and 2) How does this electron delivery differ when utilizing oxygen or hydrogen peroxide as a cosubstrate? Using a computational approach, potential paths of electron transfer (ET) to the active site copper ion were identified in a representative AA9 family PMO from (PMO9E).
View Article and Find Full Text PDFProc Natl Acad Sci U S A
January 2025
Department of Plant Pathology, College of Plant Protection, China Agricultural University, Beijing 100193, China.
Host plants and various fungicides inhibit plant pathogens by inducing the release of excessive reactive oxygen species (ROS) and causing DNA damage, either directly or indirectly leading to cell death. The mechanisms by which the oomycete manages ROS stress resulting from plant immune responses and fungicides remains unclear. This study elucidates the role of histone acetylation in ROS-induced DNA damage responses (DDR) to adapt to stress.
View Article and Find Full Text PDFJ Cancer Res Ther
December 2024
Department of Medical Ultrasound, Shandong Provincial Qianfoshan Hospital, Shandong University, Jinan, Shandong, People's Republic of China.
Introduction: Cancer cachexia (CC) is characterized by weight loss with specifically reduced skeletal muscles and adipose tissues in patients with late-stage cancer. Dihydroartemisinin (DHA), an effective antimalarial derivative of artemisinin, has been demonstrated to have anti-inflammatory and antitumor properties.
Materials And Methods: This study examined the effects of DHA on the Lewis lung carcinoma (LLC)-induced CC mouse model.
FASEB J
January 2025
Department of Eye Center, Xiangya Hospital, Central South University, Changsha, China.
Fatty acid binding proteins (FABPs) are a class of small molecular mass intracellular lipid chaperone proteins that bind to hydrophobic ligands, such as long-chain fatty acids. FABP5 expression was significantly upregulated in the N-methyl-d-aspartic acid (NMDA) model, the microbead-induced chronic glaucoma model, and the DBA/2J mice. Previous studies have demonstrated that FABP5 can mediate mitochondrial dysfunction and oxidative stress in ischemic neurons, but the role of FABP5 in oxidative stress and cell death in retina NMDA injury models is unclear.
View Article and Find Full Text PDFUpdates Surg
January 2025
Department of Gastrointestinal Surgery, The First Affiliated Hospital of Chongqing Medical University, Chongqing, 400016, China.
The purpose of this study was to identify whether the preoperative hemoglobin to albumin ratio (HAR) could predict the prognosis of patients who underwent colorectal cancer (CRC) radical resection. This study enrolled 4018 consecutive CRC patients, calculating HAR as the hemoglobin count divided by albumin count. Patients were divided into the high and low HAR groups based on a cut-off value (0.
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