Optimizing Concentration of Polyethelene Glycol for Exosome Isolation from Plasma for Downstream Application.

BACKGROUND: Exosomes are ubiquitous extracellular nanovesicles secreted from almost all living cells that are thought to be involved in several important cellular processes, including cell-cell communication and signaling. Exosomes serve as a liquid biopsy tool for clinical and translational research. Although many techniques have been used to isolate exosomes, including ultracentrigation, size-exclusion chromatography, and immunocapturing-based techniques, these techniques are not convenient, they require expensive instrumentation, and they are unhandy for clinical samples. Precipitation techniques from available commercial kits that contain polyethelene glycol (PEG) are now widely used, but these kits are expensive, especially if a large number of biological samples are to be processed. OBJECTIVE: the purpose of this study is to compare and optimize the efficacy of different concentrations of PEG with two commercial kits ExoQuick (SBI) and Total Exosome Isolation (TEI) from Invitrogen in human plasma. METHODS AND MATERIALS: we determined exosome quantity, size distribution, marker expression, and downstream application. RESULTS: among the precipitation methods, we found the size of particles and concentrations with 10-20% PEG are similar to ExoQuick and better than TEI. Interestingly, we detected cfDNA with ExoQuick and 10-20% PEG but not TEI and 5% PEG. Moreover, 10% PEG detection of miR-122 and miR-16 expression was superior to ExoQuick and TEI. Furthermore, in proteomics results it also found the identified proteins better than commercial kits but there was a high level of contamination of other proteins in serum. CONCLUSIONS: together, these findings show that an optimal concentration of 10% PEG serves as a guide for use with clinical samples in exosome isolation for downstream applications.

A single-stage computer-guided gap arthroplasty with simultaneous patient-specific total joint replacement with a novel flat fossa design: A case report.

INTRODUCTION AND IMPORTANCE: The computer-guided approach for the patient-specific TMJ replacement is considered an ultimate reliable option in advanced cases. However, dislocation of the condylar head could happen with the concave fossa design. A flat design was described and used in this case. CASE PRESENTATION: A 15 years old male patient with mandibular asymmetry and class IV recurrent ankylosis of the right TMJ received a patient-specific artificial joint with computer-guided gap arthroplasty and orthognathic corrective mandibular surgery for the left side. The fossa component was made entirely flat, and the patient was followed up over the next year. CLINICAL DISCUSSION: Customized TMJ prosthetic solutions are reliable in advanced cases, especially when facial corrections are indicated; however, the commonly used concave design showed reported dislocations requiring some design modifications as proposed in the presented case. CONCLUSION: The flat fossa design of the artificial TMJ secures the same results as the anatomical fossa design without the incidence of dislocation.

Toxicity of functionalized multi-walled carbon nanotubes on bone mesenchymal stem cell in rats.

Carbon nanotubes (CNTs) are promising biomaterials in the medical field, especially in tissue engineering of bone. However, the use of CNTs is largely confined by its unfavorable solubility and toxicity. To improve solubility and biocompatibility of CNTs, functionalization has been proven to be an effective strategy. Although various functionalized CNTs have been extensively studied, only few CNTs have the desired qualities. We compared the toxicity of several promising functionalized multi-walled carbon nanotubes (MWCNTs) on rat bone-marrow derived stem cells (BMSCs). Cell experiments showed that while acid oxidation (AO)-MWCNTs and Raw-MWCNTs exhibited significant toxicity on BMSCs, polyethylene glycols (PEG)-MWCNTs and hydroxyapatit (HA)-MWCNTs had favorable biocompatibility and a trivial effect on BMSCs. Possible mechanisms for the cytotoxicity on BMSCs included mitochondrisome and deoxyribonucleic acid damage, increased oxidative stress and damaging of cellular membranes. Our data indicated that PEG-MWCNTs and HA-MWCNTs may be promising materials for bio-related applications.

In Vitro and In Vivo Correlation of Bone Morphogenetic Protein-2 Release Profiles from Complex Delivery Vehicles.

Local sustained delivery of bioactive molecules from biomaterials is a promising strategy to enhance bone regeneration. To optimize delivery vehicles for bone formation, the design characteristics are tailored with consequential effect on bone morphogenetic protein-2 (BMP-2) release and bone regeneration. Complying with the 3R principles (Replacement, Reduction, and Refinement), the growth factor release is often investigated in vitro using several buffers to mimic the in vivo physiological environment. However, this remains an unmet need. Therefore, this study investigates the in vitro-in vivo correlation (IVIVC) of BMP-2 release from complex delivery vehicles in several commonly used in vitro buffers: cell culture model, phosphate buffered saline, and a strong desorption buffer. The results from this study showed that the release environment affected the BMP-2 release profiles, creating distinct relationships between release versus time and differences in extent of release. According to the guidance set by the U.S. Food and Drug Administration (FDA), IVIVC resulted in level A internal predictability for individual composites. Since the IVIVC was influenced by the BMP-2 loading method and composite surface chemistry, the external predictive value of the IVIVCs was limited. These results show that the IVIVCs can be used for predicting the release of an individual composite. However, the models cannot be used for predicting in vivo release for different composite formulations since they lack external predictability. Potential confounding effects of drug type, delivery vehicle formulations, and application site should be added to the equation to develop one single IVIVC applicable for complex delivery vehicles. Altogether, these results imply that more sophisticated in vitro systems should be used in bone regeneration to accurately discriminate and predict in vivo BMP-2 release from different complex delivery vehicles.

Surface cross-linked UHMWPE using peroxides.

Crosslinking of ultra-high molecular weight polyethylene (UHMWPE) has been successfully used to improve its wear performance. Wear is a surface phenomenon and limiting crosslinking to a layer only on the surface is desirable, as crosslinking of the bulk of the implant reduces its mechanical strength and toughness. We present a novel technique to surface crosslink consolidated UHMWPE/vitamin-E blends by diffusing an organic peroxide into the polymer at moderate temperatures, followed by heating to above the peroxide decomposition temperature to cause crosslinking on the surface. We characterized the surface crosslink density and wear rate of surface crosslinked UHMWPE/vitamin-E blends with two different types of peroxides. Both peroxides resulted in surface crosslinking with an increase in wear resistance comparable to the state-of-the-art highly crosslinked UHMWPE used for orthopedic implants. The addition of the antioxidant vitamin-E led to higher oxidation resistance. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:2551-2556, 2017.

Etchant-based design of gold tip apexes for plasmon-enhanced Raman spectromicroscopy.

In this paper, we gain insight into the design and optimization of plasmonic (metallic) tips prepared with dc-pulsed voltage electrochemical etching gold wires, provided that, a duty cycle is self-tuned. Physically, it means that etching electrolyte attacks the gold wire equally for all pulse lengths, regardless of its surface shape. Etchant effect on the reproducibility of a curvature radius of the tip apex is demonstrated. It means that the gold conical tips can be designed chemically with a choice of proper etchant electrolyte. It is suggested to use a microtomed binary polymer blend consisting of polyamide and low density polyethylene, as a calibration grating, for optimizing and standardizing tip-enhanced Raman scattering performance.

Artificial eye amplitudes and characteristics in enucleated socket with porous polyethylene spherical and quad-motility implant

PURPOSE: To compare artificial eye amplitudes in enucleated socket with porous polyethylene either spherical or quad-motility implant and study the characteristics of artificial eyes fit with the two orbital implants. METHODS: A total of 21 patients were prospectively studied who underwent enucleation because of an intraocular melanoma and the randomization defined a porous polyethylene either spherical or quad-motility orbital implant. Measurements of the amplitude of the artificial eye were obtained with prism and digital photos. The software Scion Image analyzed the digital photos (www.scioncorp.com) and the quantitative data were allocated to groups. The measurements (height, length, thickness) and weight of the 21 artificial eyes were analyzed. Student's t-test was performed to determine the significance of difference between groups (p<0.05). RESULTS: There was no statistically significant difference of the artificial eye amplitude analyzed by means of prisms between both orbital implants (p>0.05 for all directions). On analyzing the digital photos, the artificial eye with spherical implant showed higher artificial eye amplitude downward (p=0.009) among patients older than 55 years old, rightward (p=0.036) and downward (p=0.008) among the 9 patients with enucleated right eye. Height and length were similar in the 21 artificial eyes but those artificial eyes fit with quad-motility orbital implants were statistically significant thicker (p<0.001) and heavier (p=0.001). CONCLUSIONS: The similar amplitude of movement of artificial eyes was observed with both spherical and quad-motility orbital implants. Artificial eyes fit with quad-motility orbital implant are significantly thicker and heavier than those fit with spherical orbital implant.

OBJETIVOS: Comparar a amplitude de movimento da prótese ocular em cavidade enucleada e com implante orbitário esférico e "quad-motility" e estudar as características das próteses oculares adaptadas com os dois modelos de implantes orbitários. MÉTODOS: Vinte e um pacientes foram prospectivamente estudados após a enucleação devido a melanoma intra-ocular e cuja randomização definiu o implante orbitário de polietileno poroso nos modelos esférico e "quad-motility". Medidas da amplitude da prótese ocular foram obtidas com prisma e fotografia digital. O programa Scion Image analisou as fotos digitais (www.scioncorp.com) e os resultados foram distribuídos por grupos. As medidas (altura, comprimento, espessura) e o peso das 21 próteses também foram analisados. O teste de t foi realizado para determinar a significância da diferença entre os grupos (p<0,05). RESULTADOS: Não houve diferença significante na amplitude do movimento das próteses oculares, analisada com a interposição do prisma em ambos implantes orbitários (p>0,05 em todas as posições). Ao analisar a fotografia digital, as próteses adaptadas com implante esférico apresentaram maior amplitude de movimento na infraversão (p=0,009) para pacientes acima de 55 anos, infraversão (p=0,008) e dextroversão (p=0,036) nos nove pacientes com o olho direito enucleado. Altura e comprimento foram similares nas 21 próteses oculares. Próteses oculares adaptadas com implante "quad-motility" foram significantemente mais espessas (p<0,001) e pesadas (p=0,001). CONCLUSÕES: A amplitude de movimento das próteses oculares foi similar nos implantes esférico e "quad-motility". As próteses oculares adaptadas com implante "quad-motility" são significantemente mais espessas e pesadas do que as adaptadas com implante esférico.

Uso do implante esférico Medpor ™: análise de 61 cirurgias orbitárias / Use of Medpor ™ spherical implant: analysis of 61 orbital surgeries

OBJETIVO: Analisar o uso do implante biointegrável Medpor™ em cirurgias de evisceração, enucleação ou implantação secundária em cavidades anoftálmicas. MÉTODOS: Em 61 cirurgias foi utilizado o implante orbitário Medpor™ . Em 18 casos de evisceração, não houve necessidade do revestimento do implante. Em 12 cirurgias de enucleação e implantação secundária o material utilizado para revestir o implante foi duramater homóloga. Nas demais 31 cirurgias, o revestimento foi de material autólogo (esclera, derme, músculo orbicular ou cartilagem auricular), utilizando-se a técnica de "solidéu", recobrindo apenas a superfície anterior do Medpor ™ . RESULTADOS: Os pacientes foram operados no período de janeiro/1998 a dezembro/2004, com tempo de seguimento médio de 30 meses. Em todos os casos houve aceitação do implante, permitindo boa adaptação da prótese. Em dois pacientes ocorreu exposição tardia do implante: o primeiro caso foi corrigido pelo reposicionamento do implante na cavidade, e no segundo caso a exposição foi coberta com um retalho de tarso. CONCLUSÕES: Na nossa experiência o implante Medpor ™ apresenta boa aceitação com taxa de exposição pequena do mesmo (apenas 2 casos), nenhum caso de infecção ou migração, e boa adaptação da prótese em todos os pacientes. O uso de tecido autólogo para revestir a superfície anterior do implante elimina o risco inerente ao uso de tecidos homólogos.

PURPOSE: To analyze the use of Medpor ™ biointegrated implant in surgeries of evisceration, enucleation or secondary implantation in anophthalmic sockets. METHODS: The Medpor™ orbitary implant was used in 61 surgeries. In 18 cases of evisceration the implant's wrapping was not necessary. In 12 enucleation and secondary implantation surgeries the utilized material to wrap the implant was homologous duramater. In the other 31 surgeries, the implant wrapping was made from autologous tissue (sclera, dermis, orbicular muscle or auricular cartilage), utilizing the "cap" technique - covering only the anterior surface of Medpor™. RESULTS: The patients were operated from January 1998 to December 2004 with an average follow-up period of 30 months. In all cases the implant was well accepted, allowing for a good adaptation of the prosthesis. Late exposure of the implant occurred in two patients: the first was corrected by the replacement of the implant in the cavity, while in the second case the exposure was wrapped with a tarsus flap. CONCLUSIONS: In our experience the Medpor ™ implant presents good acceptance, with a small exposure rate (only 2 cases), no infection or migration cases, and a good prosthesis adaptation in all patients. The use of autologous tissue to wrap the implant's anterior surface eliminates the inherent risk of using homologous tissues.

Relativity study during polyethelene debris cytokine and hip prosthesis loosening / 中国矫形外科杂志

0.05),but the integrated arthoplasty group had significant differences from the other two groups(P