scholarly journals A Novel Nanocomposite Particle of Hydroxyapatite and Silk Fibroin: Biomimetic Synthesis and Its Biocompatibility

2010 ◽  
Vol 2010 ◽  
pp. 1-7 ◽  
Author(s):  
Lin Niu ◽  
Rui Zou ◽  
Qida Liu ◽  
Quanli Li ◽  
Xinmin Chen ◽  
...  

A novel bone-like biomaterial of hydroxyapatite (HAP) and silk fibroin (SF) composite was developed by biomimetic synthesis. The composite was precipitated from drops of Ca(OH)2suspension andH3PO4solution with SF. With this method, the HAP nanocrystals were obtained by self-assembling on a SF surface whose c-axis was aligned with the long-axis direction of SF in microstructures; this shares the same misconstrues of collagen and HAP with that in the natural bone. The HAP/SF composite then demonstrated that it could promote osteoblast proliferationin vitroand new bone formationin vivo. The novel biomaterial is a promising material for bone replacement and regeneration.

2006 ◽  
Vol 309-311 ◽  
pp. 801-804 ◽  
Author(s):  
S.B. Cho ◽  
Akari Takeuchi ◽  
Ill Yong Kim ◽  
Sang Bae Kim ◽  
Chikara Ohtsuki ◽  
...  

In order to overcome the disadvantage of commercialized PMMA bone cement, we have developed novel PMMA-based bone cement(7P3S) reinforced by 30 wt.% of bioactive CaO-SiO2 gel powders to induce the bioactivity as well as to increase mechanical property for the PMMA bone cement. The novel 7P3S bone cement hardened after mixing for about 7 minutes. For in vitro evaluation, apatite forming ability of it was investigated using SBF. When the novel 7P3S bone cement was soaked into SBF, it formed apatite on its surfaces within 1 week Furthermore; there is no decrease in its compressive strength within 9 weeks soaking in SBF. It is though that hardly decrease in compressive strength of 7P3S bone cement in SBF is due to the relative small amount of gel powder or its spherical shape and monosize. In vivo evaluation of the novel 7P3S bone cement was carried out using rabbit. After implantion into rabbit tibia for several periods, the interface between novel bone cement and natural bone was evaluated by CT images. According to the results, the novel bone cement directly contact to the natural bone without fibrous tissue after implantation for 4 weeks. This results indicates that the newly developed 7P3S bone cement can bond to the living bone and also be effectively used as bioactive bone cement without decrease in mechanical property.


2020 ◽  
Author(s):  
Wenhao Zhou ◽  
Teng Zhang ◽  
Jianglong Yan ◽  
QiYao Li ◽  
Panpan Xiong ◽  
...  

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Olanrewaju Ayodeji Durojaye ◽  
Nkwachukwu Oziamara Okoro ◽  
Arome Solomon Odiba

Abstract Background The novel coronavirus SARS-CoV-2 is currently a global threat to health and economies. Therapeutics and vaccines are in rapid development; however, none of these therapeutics are considered as absolute cure, and the potential to mutate makes it necessary to find therapeutics that target a highly conserved regions of the viral structure. Results In this study, we characterized an essential but poorly understood coronavirus accessory X4 protein, a core and stable component of the SARS-CoV family. Sequence analysis shows a conserved ~ 90% identity between the SARS-CoV-2 and previously characterized X4 protein in the database. QMEAN Z score of the model protein shows a value of around 0.5, within the acceptable range 0–1. A MolProbity score of 2.96 was obtained for the model protein and indicates a good quality model. The model has Ramachandran values of φ = − 57o and ψ = − 47o for α-helices and values of φ = − 130o and ψ = + 140o for twisted sheets. Conclusions The protein data obtained from this study provides robust information for further in vitro and in vivo experiment, targeted at devising therapeutics against the virus. Phylogenetic analysis further supports previous evidence that the SARS-CoV-2 is positioned with the SL-CoVZC45, BtRs-BetaCoV/YN2018B and the RS4231 Bat SARS-like corona viruses.


2021 ◽  
Vol 26 (3) ◽  
pp. 349-361
Author(s):  
Napoleon-Nikolaos Vrettos ◽  
Peng Wang ◽  
Yan Zhou ◽  
Clive J. Roberts ◽  
Jinyi Xu ◽  
...  

2021 ◽  
Vol 11 (2) ◽  
pp. 92 ◽  
Author(s):  
Babita Shashni ◽  
Yukio Nagasaki

Elevated reactive oxygen species (ROS) have been implicated as significant for cancer survival by functioning as oncogene activators and secondary messengers. Hence, the attenuation of ROS-signaling pathways in cancer by antioxidants seems a suitable therapeutic regime for targeting cancers. Low molecular weight (LMW) antioxidants such as 2,2,6,6-tetramethylpyperidine-1-oxyl (TEMPO), although they are catalytically effective in vitro, exerts off-target effects in vivo due to their size, thus, limiting their clinical use. Here, we discuss the superior impacts of our TEMPO radical-conjugated self-assembling antioxidant nanoparticle (RNP) compared to the LMW counterpart in terms of pharmacokinetics, therapeutic effect, and adverse effects in various cancer models.


2007 ◽  
Vol 539-543 ◽  
pp. 710-715
Author(s):  
Kotaro Kuroda ◽  
Ryoichi Ichino ◽  
Masazumi Okido

Hydroxyapatite (HAp) coatings were formed on cp titanium plates and rods by the thermal substrate method in an aqueous solution that included 0.3 mM Ca(H2PO4)2 and 0.7 mM CaCl2. The coating experiments were conducted at 40-140 oC and pH = 8 for 15 or 30 min. The properties for the coated samples were studied using XRD, EDX, FT-IR, and SEM. All the specimens were covered with HAp, which had different surface morphologies such as net-like, plate-like and needle-like. After cleaning and sterilization, all the coated specimens were subjected to in vivo and vitro testing. In the in vitro testing, the mouse osteoblast-like cells (MC3T3-E1) were cultured on the coated and non-coated specimens for up to 30 days. Moreover, the specimens (φ2 x 5 mm) were implanted in rats femoral for up to 8 weeks, the osseoinductivity on them were evaluated. In in vitro evaluations, there were not significant differences between the different surface morphologies. In in vivo evaluations, however, two weeks postimplantation, new bone formed on both the HAp coated and non-coated titanium rods in the cancellous and cortical bone. The bone-implant contact ratio, which was used for the evaluation of new bone formation, was significantly dependent on the surface morphology of the HAp, and the results demonstrated that the needle-like coating appears to promote rapid bone formation.


2012 ◽  
Vol 32 (6) ◽  
pp. 559-566 ◽  
Author(s):  
Yan Xu ◽  
Feng Zhi ◽  
Guangming Xu ◽  
Xiaolei Tang ◽  
Sheng Lu ◽  
...  

MDR (multidrug-resistance) represents a major obstacle to successful cancer chemotherapy and is usually accomplished by overexpression of P-gp (P-glycoprotein). Much effort has been devoted to developing P-gp inhibitors to modulate MDR. However, none of the inhibitors on the market have been successful. 1416 [1-(2,6-dimethylphenoxy)-2-(3,4-dimethoxyphenylethylamino)propane hydrochloride (phenoprolamine hydrochloride)] is a new VER (verapamil) analogue with a higher IC50 for blocking calcium channel currents than VER. In the present paper, we examined the inhibition effect of 1416 on P-gp both in vitro and in vivo. 1416 significantly enhanced cytotoxicity of VBL (vinblastine) in P-gp-overexpressed human multidrug-resistant K562/ADM (adriamycin) and KBV cells, but had no such effect on the parent K562 and KB cells. The MDR-modulating function of 1416 was further confirmed by increasing intracellular Rh123 (rhodanmine123) content in MDR cells. Human K562/ADM xenograft-nude mice model verified that 1416 potentiates the antitumour activity of VBL in vivo. RT-PCR (reverse transcriptase-PCR) and FACS analysis demonstrated that the expression of MDR1/P-gp was not affected by 1416 treatment. All these observations suggest that 1416 could be a promising agent for overcoming MDR in cancer chemotherapy.


2012 ◽  
Vol 63 (4) ◽  
pp. 606-612 ◽  
Author(s):  
Arthur L. Nikkel ◽  
Brenda Martino ◽  
Stella Markosyan ◽  
Jill-Desiree Brederson ◽  
Rodrigo Medeiros ◽  
...  

2014 ◽  
Vol 59 (2) ◽  
pp. 1341-1343 ◽  
Author(s):  
Nathan P. Wiederhold ◽  
Laura K. Najvar ◽  
Annette W. Fothergill ◽  
Rosie Bocanegra ◽  
Marcos Olivo ◽  
...  

ABSTRACTWe evaluated thein vitroandin vivoactivities of the investigational arylamidine T-2307 against echinocandin-resistantCandida albicans. T-2307 demonstrated potentin vitroactivity, and daily subcutaneous doses between 0.75 and 6 mg/kg of body weight significantly improved survival and reduced fungal burden compared to placebo control and caspofungin (10 mg/kg/day) in mice with invasive candidiasis caused by an echinocandin-resistant strain. Thus, T-2307 may have potential use in the treatment of echinocandin-resistantC. albicansinfections.


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