scholarly journals Surface Properties and MC3T3-E1 Cell Response of Cortical Bone Allografts Modified with Low-Concentration Phosphoric Acid

2017 ◽  
Vol 41 (4) ◽  
pp. 1572-1583 ◽  
Author(s):  
Zengfa Huang ◽  
Cheng Cheng ◽  
Jing Wang ◽  
Hui Wei ◽  
Xianzhe Liu ◽  
...  
Keyword(s):  
Contact Angle ◽  
Phosphoric Acid ◽  
Western Blotting ◽  
Animal Experiments ◽  
Biomechanical Properties ◽  
Potential Method ◽  
Infection Model ◽  
Low Concentration ◽  
Model Studies ◽  
Bone Allografts

Background/Aims: This experimental study aimed to evaluate the effect of low-concentration phosphoric acid on the surface structure of cortical allografts. Methods: Allogenic cortical bones were obtained from femurs and tibias of New Zealand white rabbits. The bones were modified by treatment with various concentrations of phosphoric acid (10%, 20% or 30%) for 10, 30 or 60 minutes, then evaluated by the following methods: 3-(4,5-Dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) and LIVE/DEAD assay, alkaline phosphatase (ALP) assay, biomechanical properties testing, contact angle detection, quantitative real-time polymerase chain reaction (Q-PCR), western blotting and scanning electron microscopy (SEM). Results: Compared with the other groups, the group modified with 10% H3PO4 for 10 minutes had lower cytotoxicity according to MTT and LIVE/DEAD assays, higher hydrophilicity in the contact angle detection test and greater stability in the biomechanical properties test. Moreover, an up-regulation of osteopontin (OPN) in bones modified with 10% H3PO4 was observed by Q-PCR and western blotting. In addition, ALP assay and SEM showed that surface porosity and osteoinductivity were increased in the group modified with 10% H3PO4. Conclusions: Low-concentration phosphoric acid may be a potential method for surface modification of cortical allografts. Further animal experiments and animal infection model studies are required to validate the efficacy of surface-modified cortical allografts to repair large segmental bone defects.

The Effects of Donor Age and Strain Rate on the Biomechanical Properties of Bone-Patellar Tendon-Bone Allografts

1994 ◽  
Vol 22 (3) ◽  
pp. 328-333 ◽  
Author(s):  
Field T. Blevins ◽  
Aaron T. Hecker ◽  
Gregory T. Bigler ◽  
Arthur L. Boland ◽  
Wilson C. Hayes
Keyword(s):  
Strain Rate ◽  
Patellar Tendon ◽  
Biomechanical Properties ◽  
Donor Age ◽  
Bone Allografts ◽  
Bone Patellar Tendon

Effects of 60Co gamma radiation dose on initial structural biomechanical properties of ovine bone—patellar tendon—bone allografts

2010 ◽  
Vol 12 (2) ◽  
pp. 89-98 ◽  
Author(s):  
Kirk C. McGilvray ◽  
Brandon G. Santoni ◽  
A. Simon Turner ◽  
Simon Bogdansky ◽  
Donna L. Wheeler ◽  
...  
Keyword(s):  
Radiation Dose ◽  
Gamma Radiation ◽  
Patellar Tendon ◽  
Biomechanical Properties ◽  
Bone Allografts ◽  
60Co Gamma ◽  
Gamma Radiation Dose ◽  
60Co Gamma Radiation ◽  
Bone Patellar Tendon

scholarly journals Evaluation of glycerol-preserved bone allografts in cervical spine fusion: a prospective, randomized controlled trial

2015 ◽  
Vol 22 (1) ◽  
pp. 1-10 ◽  
Author(s):  
R. Scott Graham ◽  
Brian J. Samsell ◽  
Allison Proffer ◽  
Mark A. Moore ◽  
Rafael A. Vega ◽  
...  
Keyword(s):  
Outcome Measures ◽  
Controlled Trial ◽  
Biomechanical Properties ◽  
Secondary Outcome ◽  
Radiographic Evaluation ◽  
Bone Allografts ◽  
Physical Measurements ◽  
Treatment Type ◽  
Freeze Dried

OBJECT Bone allografts used for interbody spinal fusion are often preserved through either freeze drying or lowtemperature freezing, each having disadvantages related to graft preparation time and material properties. In response, a glycerol preservation treatment has been developed to maintain the biomechanical properties of allografts at ambient temperatures, requiring no thawing or rehydration and minimal rinsing prior to implantation. The authors conducted a prospective randomized study to compare the clinical results of glycerol-preserved Cloward dowels and those of freezedried Cloward dowels in anterior cervical discectomy and fusion. The primary outcome measures were evidence of fusion and graft subsidence, and the secondary outcome measures included adverse events, pain, and neck disability scores. METHODS Of 106 patients, 53 (113 levels of surgery) were randomly assigned to the glycerol-preserved graft group and 53 (114 levels of surgery) to the freeze-dried graft group. Subsidence was assessed at 3 and 6 months after implantation. Evidence of fusion was evaluated radiographically at 6 months postimplantation. Subsidence was quantitatively assessed based on physical measurements obtained from radiographs by using calibrated comparators, whereas fusion was also evaluated visually. Surgeons were blinded to treatment type during visual and physical assessments of the patients and the radiographs. RESULTS No one in either group had evidence of complete nonunion according to radiographic evaluation at the 6-month follow-up. Average subsidence for all graft-treated levels was 2.11 mm for the glycerol-preserved group and 2.73 mm for the freeze-dried group at the 3-month follow-up and 2.13 and 2.83 mm at the 6-month follow-up, respectively. The 2 treatment groups were statistically equivalent (p = 0.2127 and 0.1705 for the 3- and 6-month follow-up, respectively). No differences were noted between the graft types in terms of adverse event incidence or severity. CONCLUSIONS Glycerol-preserved bone allografts exhibit fusion results and subsidence values similar to those of their freeze-dried counterparts, potentially more favorable biomechanical properties, and significantly shorter preparation times.

Biomechanical Properties of Bone Allografts

1983 ◽  
Vol &NA; (174) ◽  
pp. 54???57 ◽  
Author(s):  
RICHARD R. PELKER ◽  
GARY E. FRIEDLAENDER ◽  
THOMAS C. MARKHAM
Keyword(s):  
Biomechanical Properties ◽  
Bone Allografts

Bafilomycin A1 Targets Both Autophagy and Apoptosis Pathways in Pediatric t(1;19) Pre-B Acute Lymphoblastic Leukemia Cells

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 3699-3699
Author(s):  
Na Yuan ◽  
Lin Song ◽  
Suping Zhang ◽  
Weiwei Lin ◽  
Yan Cao ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Bone Marrow ◽  
Acute Lymphoblastic Leukemia ◽  
Western Blotting ◽  
Bone Marrow Cells ◽  
Lymphoblastic Leukemia ◽  
Leukemia Cells ◽  
Primary Cells ◽  
Bafilomycin A1 ◽  
Low Concentration

Abstract The t (1; 19) subtype leukemia accounts for a quarter of pre-B acute lymphoblastic leukemia (ALL) and up to 5% of all ALL patients. Despite plausible remission rate, current treatment regimen on the pediatric pre-B ALL is associated with side effects and CNS relapse, which poses the need for more effective and safer drugs. Bafilomycin A1 (Baf-A1) is known as an inhibitor of late phase of autophagy by inhibiting fusion between autophagosomes and lysosomes as well as by inhibiting lysosomal degradation. Here we show that Baf-A1 of low concentration (1 nM) effectively and specifically inhibits and kills the pre-B ALL cells. E2A/Pbx1 fusion gene positivepre-B ALL 697 cells were used for In vitro experiments. The results of flow cytometry analysis and western blotting showed that Baf-A1 induced cell cycle arrest and proliferation inhibition of ALL cells by upregualting cell cycle negative regulators and downregulating cell cycle positive regulators. In contrast, AML and CML cell lines were insensitive to Baf-A1 treatment. Western blotting and confocal observation on protein LC3 also showed that Baf-A1 at 1 nM blocked basal autophagic flux. Baf-A1 treatment activated mTOR signaling and induced the formation of Becn1–Bcl-2 complex to inhibit the induction of autophagy. Furthermore, apoptosis was induced in ALL cells treated with Baf-A1 for 72 h. However, procaspase-3 and poly-(ADP-ribose) polymerase (PARP) were not cleaved in these cells. We observed that AIF relocalized to the nucleus after 72h Baf-A1 treatment by confocal and immunoblotting. Knockdown of AIF significantly attenuated apoptosis induced by Baf-A1. These data suggest that Baf-A1 targets mitochondria membrane to trigger apoptosis via AIF pathway. In the in vivo experiment, Baf-A1 treatment extended survival and improved pathology of 697 xenograft mice, and significantly reduced the E2A/PBX1 positive leukemia cells in the bone marrow of mice. In vivomouse toxicity assay confirms Baf-A1 as a safe compound. The bone marrow cells of pre-B ALL leukemia patients were sorted against CD133+CD19+ markers, and treatment with Baf-A1 induced a clear inhibition on the CD133+CD19+ primary cells with a significant increased cell death in the sorted B-ALL patient samples. Conversely, Baf-A1 had no inhibitory effect on the bone marrow cells isolated from acute myeloid leukemia patients and healthy people. In summary, Baf-A1 treatment at low concentration effectively and specifically inhibited autophagy by activating mTOR and inducing beclin1-Bcl-2 interaction and induced AIF-dependent apoptosis in t (1; 19) pre-B ALL 697 cells. In the pre-B ALL xenograft mouse model, Baf-A1 specifically targets the leukemia cells while sparing normal cells. More importantly, Baf-A1 potently inhibits and kills the primary cells from pediatric pre-B ALL patients both at initial diagnosis and relapse without compromising normal human hematopoietic cells, all proposing Baf-A1 as a promising drug candidate for this pre-B ALL. Disclosures No relevant conflicts of interest to declare.

Inkjet Printing of Enzymes for Glucose Sensors

2009 ◽  
Vol 1191 ◽  
Author(s):  
Christopher Cook ◽  
TianMing Wang ◽  
Brian Derby
Keyword(s):  
Contact Angle ◽  
Glucose Oxidase ◽  
Inkjet Printing ◽  
Electrode Surface ◽  
Potential Method ◽  
Test Methods ◽  
Surface Topology ◽  
Carbon Surface ◽  
Sensor Applications ◽  
Drop On Demand

AbstractDrop on demand inkjet printing is a potential method for depositing enzymes onto electrodes for sensor applications. This technology offers drop sizes in the region of picolitres and allows a production rate up to 200 mm/s. This enables not only a more rapid method of device prototyping but also a method for possible miniaturization of the sensors themselves. However, previous work [1] has indicated that inkjet printing may cause a drop in the retained activity of the enzyme.Here we assess the criticality of this drop in activity and how it may have been influenced by changes to the protein structure during printing. The enzyme used is glucose oxidase and the test methods include; protein analysis, in the form of analytical ultra-centrifugation and circular dichroism, scanning electron microscopy, atomic force microscopy and phase contrast microscopy, to analyse the surface topology of the electrodes and contact angle analysis, to assess the degree of spreading and the interactions between the drops and the electrode surface.With glucose oxidase there is no change in the conformation, structure or hydrodynamic radius of the protein after printing. The analysis of the electrode surface shows a relatively smooth surface that is made up of individual graphite flakes laid down by a screen printing method. When contact angle and spreading analysis is carried out it demonstrates reliability in the printing process as well as a drop in the sessile volume of the drop in conjunction with a growth in the base diameter of the drop as expected. It also demonstrates a fairly quick rate of evaporation of the drop. Upon the addition of surfactants to the solution the spreading is seen to be more extensive in relation to the surfactant concentration, although some initial reduction in experienced at low concentrations which may be due to the absorption into the carbon surface.

Surface Microanalysis and Chemical Imaging of Early Dentin Remineralization

2013 ◽  
Vol 20 (1) ◽  
pp. 245-256 ◽  
Author(s):  
Manuel Toledano ◽  
Inmaculada Cabello ◽  
Miguel Angel Cabrerizo Vílchez ◽  
Miguel Angel Fernández ◽  
Raquel Osorio
Keyword(s):  
Contact Angle ◽  
Phosphoric Acid ◽  
Artificial Saliva ◽  
Chemical Imaging ◽  
Organic Content ◽  
Phosphate Solution ◽  
Ζ Potential ◽  
Mineral Components ◽  
Physical And Chemical ◽  
Demineralized Dentin

AbstractThis study reports physical and chemical changes that occur at early dentin remineralization stages. Extracted human third molars were sectioned to obtain dentin discs. After polishing the dentin surfaces, three groups were established: (1) untreated dentin (UD), (2) 37% phosphoric acid application for 15 s (partially demineralized dentin—PDD), and (3) 10% phosphoric acid for 12 h at 25° C (totally demineralized dentin—TDD). Five different remineralizing solutions were used: chlorhexidine (CHX), artificial saliva (AS), phosphate solution (PS), ZnCl2, and ZnO. Wettability (contact angle), ζ potential and Raman spectroscopy analysis were determined on dentin surfaces. Demineralization of dentin resulted in a higher contact angle. Wettability decreased after immersion in all solutions. ζ potential analysis showed dissimilar performance ranging from −6.21 mV (TDD + AS) up to 3.02 mV (PDD + PS). Raman analysis showed an increase in mineral components after immersing the dentin specimens, in terms of crystallinity, mineral content, and concentration. This confirmed the optimal incorporation and deposition of mineral on dentin collagen. Organic content reflected scarce changes, except in TDD that appeared partially denatured. Pyridinium, as an expression of cross-linking, appeared in all spectra except in specimens immersed in PS.

scholarly journals Programmable droplet manipulation and wetting with soft magnetic carpets

2021 ◽  
Vol 118 (46) ◽  
pp. e2111291118
Author(s):  
Ahmet F. Demirörs ◽  
Sümeyye Aykut ◽  
Sophia Ganzeboom ◽  
Yuki A. Meier ◽  
Erik Poloni
Keyword(s):  
Magnetic Field ◽  
Contact Angle ◽  
Potential Method ◽  
Field Application ◽  
Small Scale ◽  
Soft Magnetic ◽  
Chemical Waste ◽  
Wetting Properties ◽  
Energy Applications ◽  
Droplet Manipulation

The ability to regulate interfacial and wetting properties is highly demanded in anti-icing, anti-biofouling, and medical and energy applications. Recent work on liquid-infused systems achieved switching wetting properties, which allow us to turn between slip and pin states. However, patterning the wetting of surfaces in a dynamic fashion still remains a challenge. In this work, we use programmable wetting to activate and propel droplets over large distances. We achieve this with liquid-infused soft magnetic carpets (SMCs) that consist of pillars that are responsive to external magnetic stimuli. Liquid-infused SMCs, which are sticky for a water droplet, become slippery upon application of a magnetic field. Application of a patterned magnetic field results in a patterned wetting on the SMC. A traveling magnetic field wave translates the patterned wetting on the substrate, which allows droplet manipulation. The droplet speed increases with an increased contact angle and with the droplet size, which offers a potential method to sort and separate droplets with respect to their contact angle or size. Furthermore, programmable control of the droplet allows us to conduct reactions by combining droplets loaded with reagents. Such an ability of conducting small-scale reactions on SMCs has the potential to be used for automated analytical testing, diagnostics, and screening, with a potential to reduce the chemical waste.

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