Bone regeneration potential of sub-microfibrous membranes with osteogenic induction of rBMSC for tissue engineering

Purpose: To examine the biocompatibility and osteoinductive potential of  sub-microfibrous membranes with cells in vitro and in vivo.Methods: Polylactic acid (PLA) and poly-ε-caprolactone (PCL) were blended at various volume ratios (PLA:PCL = 100:0, 70:30, 50:50, 30:70 and 0:100) and each membrane form was prepared by electrospinning. Cell viability,  biocompatibility, and bone regeneration were measured.Results: The membranes from the PLA/PCL blends prepared by an electrospinning process showed a range of diameter distribution ranging from 1,580 to 550 nm. The cells of 100 % PCL membrane (smallest diameter) exhibited significantly higher adhesion and proliferation than those of the other membranes. Among the  membranes from PLA/PCL blends, PCL membrane showed weak inflammatory changes in the early stages of implantation without acute or chronic inflammation. PCL membranes with osteogenically-induced cells successfully stimulated new bone formation in a rate calvarial defect model.Conclusion: The results indicate that biodegradable PCL sub-microfibrous membrane produced by electrospinning process seems to have excellent biocompatibility, and may be used as a scaffold for bone tissue engineering.Keywords: Biocompatibility, Hard tissue, Biomaterial availability, Bone remodeling, Polylactic acid, Poly-ε-caprolactone, Osteoinductive potential, Sub-microfibrous membrane

The impact of system matrix dimension on small FOV SPECT reconstruction with truncated projections

Purpose: A dedicated cardiac hybrid single photon emission computed tomography (SPECT)/CT scanner that uses cadmium zinc telluride detectors and multiple pinhole collimators for stationary acquisition offers many advantages. However, the impact of the reconstruction system matrix (SM) dimension on the reconstructed image quality from truncated projections and 19 angular samples acquired on this scanner has not been extensively investigated. In this study, the authors aimed to investigate the impact of the dimensions of SM and the use of body contour derived from adjunctive CT imaging as an object support in reconstruction on this scanner, in relation to background extracardiac activity. Methods: The authors first simulated a generic SPECT/CT system to image four NCAT phantoms with various levels of extracardiac activity and compared the reconstructions using SM in different dimensions and with/without body contour as a support for quantitative evaluations. The authors then compared the reconstructions of 18 patient studies, which were acquired on a GE Discovery NM570c scanner following injection of different radiotracers, including 99mTc-Tetrofosmin and 123I-mIBG, comparing the scanner\u27s default SM that incompletely covers the body with a large SM that incorporates a patient specific full body contour. Results: The simulation studies showed that the reconstructions using a SM that only partially covers the body yielded artifacts on the edge of the field of view (FOV), overestimation of activity and increased nonuniformity in the blood pool for the phantoms with higher relative levels of extracardiac activity. However, the impact on the quantitative accuracy in the high activity region such as the myocardium, was subtle. On the other hand, an excessively large SM that enclosed the entire body alleviated the artifacts and reduced overestimation in the blood pool, but yielded slight underestimation in myocardium and defect regions. The reconstruction using the larger SM with body contour yielded the most quantitatively accurate results in all the regions of interest for a range of uptake levels in the extracardiac regions. In patient studies, the SM incorporating patient specific body contour minimized extracardiac artifacts, yielded similar myocardial activity, lower blood pool activity, and subsequently improved myocardium-to-blood pool contrast (p\u3c0.0001) by an average of 7% (range 0%-18%) across all the patients, compared to the reconstructions using the scanner\u27s default SM. Conclusions: Their results demonstrate that using a large SM that incorporates a CT derived body contour in the reconstruction could improve quantitative accuracy within the FOV for clinical studies with high extracardiac activity

Recent Trends and Changes in the Endoscopic Spinal Surgery

In recent years, endoscopic spine surgeries have advanced dramatically. Endoscopic spine surgeries are expanding to not only the lumbar spine, but also thoracic and cervical spines. Indications for spinal endoscopic surgery have also been expanded. Central stenosis, lateral recess stenosis, and foraminal stenosis were included in surgical indications of endoscopy. Finally, endoscopic lumbar interbody fusion surgeries have been attempted

Mechanical properties of polyurethane/montmorillonite nanocomposite prepared by melt mixing

Nanocomposites from polyurethane (PU) and montmorillonite (MMT) were prepared under melt-mixing condition, by a twin screw extruder along with a compatibilizer to enhance dispersion of MMT. MMT used in this study was Cloisite 25A (modified with dimethyl hydrogenated tallow 2-ethylhexyl ammonium) or Cloisite 30B (modified with methyl tallow bis-2-hydroxyethyl ammonium). Maleic anhydride grafted polypropylene (MAPP) was used as the compatibilizer. XRD and TEM analysis demonstrated that melt mixing by a twin-screw extruder was effective in dispersing MMT through the PU matrix. The PU/Cloisite 30B composite exhibited better interlayer separation than the PU/Cloiste 25A composite. Nanoparticle dispersion was the best at 1 wt % of MMT and improved with compatibilizer content for both composites. Properties of the composites such as complex viscosity and storage modulus were higher than that of a pure PU matrix and increased with the increase in MMT content, but decreased with the increase in compatibilizer content. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/56114/1/26721_ftp.pd

Comparison of tenofovir plus lamivudine versus tenofovir monotherapy in patients with lamivudine-resistant chronic hepatitis B

Background/Aims:Tenofovir disoproxil fumarate (TDF) exhibits similar antiviral efficacy against treatment-naïve and lamivudine (LAM)-resistant chronic hepatitis B (CHB). However, there are few clinical reports on the antiviral effects of TDF–LAM combination therapy compared to TDF monotherapy in patients with LAM-resistant CHB. Methods:We investigated the antiviral efficacy of TDF monotherapy vs. TDF–LAM combination therapy in 103 patients with LAM-resistant CHB. Results:The study subjects were treated with TDF alone (n=40) or TDF–LAM combination therapy (n=63) for ≥6 months. The patients had previously been treated with TDF-based rescue therapy for a median of 30.0 months (range, 8–36 months). A virologic response (VR) was achieved in 99 patients (96.1%): 95.0% (38/40) of patients in the TDF monotherapy group and 96.8% (61/63) of patients in the TDF–LAM combination therapy group. The VR rates were not significantly different between the TDF monotherapy and TDF–LAM combination therapy groups (88.9 vs. 87.3% at month 12, and 94.4 vs. 93.7% at month 24, log-rank p=0.652). Univariate and multivariate analyses revealed that none of the pretreatment factors were significantly associated with VR. Conclusions:TDF monotherapy was as effective as TDF–LAM combination therapy for maintaining viral suppression in the vast majority of patients with LAM-resistant CHB, which suggests that TDF add-on therapy with LAM is unnecessary

Gene Transfer of Pro-opiomelanocortin Prohormone Suppressed the Growth and Metastasis of Melanoma: Involvement of ␣-Melanocyte-Stimulating Hormone-Mediated Inhibition of the Nuclear Factor B/Cyclooxygenase-2 Pathway

ABSTRACT Pro-opiomelanocortin (POMC) is a prohormone of various neuropeptides, including corticotropin, ␣-melanocyte-stimulating hormone (␣-MSH), and ␤-endorphin (␤-EP) . POMC neuropeptides are potent inflammation inhibitors and immunosuppressants and may exert opposite influences during tumorigenesis. However, the role of POMC expression in carcinogenesis remains elusive. We evaluated the antineoplastic potential of POMC gene delivery in a syngenic B16-F10 melanoma model. Adenovirus-mediated POMC gene delivery in B16-F10 cells increased the release of POMC neuropeptides in cultured media, which differentially regulated the secretion of pro-and anti-inflammatory cytokines in lymphocytes. POMC gene transfer significantly reduced the anchorage-independent growth of melanoma cells. Moreover, pre-or post-treatment with POMC gene delivery effectively retarded the melanoma growth in mice. Intravenous injection of POMC-transduced B16-F10 cells resulted in reduced foci formation in lung by 60 to 70% of control. The reduced metastasis of POMC-transduced B16-F10 cells could be attributed to their attenuated migratory and adhesive capabilities. POMC gene delivery reduced the cyclooxygenase-2 (COX-2) expression and prostaglandin (PG) E 2 synthesis in melanoma cells and tumor tissues. In addition, application of NS-398, a selective COX-2 inhibitor, mimicked the antineoplastic functions of POMC gene transfer in melanoma. The POMC-mediated COX-2 down-regulation was correlated with its inhibition of nuclear factor B (NFB) activities. Exogenous supply of ␣-MSH inhibited NFB activities, whereas application of the ␣-MSH antagonist growth hormone-releasing peptide-6 (GHRP-6) abolished the POMC-induced inhibition of NFB activities and melanoma growth in mice. In summary, POMC gene delivery suppresses melanoma via ␣-MSH-induced inhibition of NFB/COX-2 pathway, thereby constituting a novel therapy for melanoma. POMC is a multifunctional polycistronic gene located on human chromosome 2p23.3. POMC is a 31 kDa prohormone that is processed into various neuropeptides, including corticotropin, melanotropins (␣-, ␤-, and ␥-MSH), lipotropins, and ␤-endorphin (␤-EP

Efficacy of a Computerized Sensor System for Evaluation and Training of Dizzy Patients

Patients with vestibular hypofunction often experience dizziness and unsteadiness while moving their heads. Appropriate sensors can effectively detect a patient’s dynamic visual acuity and associated body balance control. Forty-one vestibular-deficit patients and 10 normal individuals were invited to participate in this study. Questionnaires, clinical assessment scales and objective measures were evaluated on participants’ first visits. After 12 sessions of training, all scales were evaluated again on vestibular-deficit patients. The computerized system was composed of sensors, including a gyro and strain gauges, data acquisition accessories and LabVIEW software. Results revealed that the system could effectively distinguish normal subjects from subjects with vestibular deficits. In addition, after a rehabilitation program, subjects’ subjective and objective performances were significantly improved. Based on our results, we concluded that the present system, which uses a gyro and strain gauges, may provide an effective method for assessing and treating vestibular-deficit patients

Hyperplastic Polyposis Syndrome Identified with a BRAF Mutation

Hyperplastic polyposis syndrome (HPS) is a rare condition characterized by the presence of numerous hyperplastic polyps (HPs) in the colon and rectum. Patients with HPS have an increased risk of colorectal cancer. This link is associated with gene mutations, especially B type Raf kinase (BRAF). However, a case of HPS associated with gene mutations has seldom been reported in Korea. Here, we describe a case of HPS in which a BRAF mutation was present in a 34-year-old woman. She had more than 110 HPs in the stomach and colorectum, which we removed. All of the polyps were diagnosed histologically as HPs, and no adenomatous or malignant changes were noted. We performed a BRAF and K-ras mutation analysis as well as a microsatellite analysis on the resected colon polyps. BRAF mutations were found in the resected colon polyps, but there was no evidence of K-RAS mutation or microsatellite instability