Non-Gaussian diffusion imaging for malignant and benign pulmonary nodule differentiation: a preliminary study.

BACKGROUND: Diffusion-weighted imaging (DWI) derived apparent diffusion coefficient (ADC) has demonstrated inconsistent results in pulmonary nodule differentiation. Diffusion kurtosis imaging (DKI), which quantifies non-Gaussian diffusion, is believed to better characterize tissue micro-structure than conventional DWI. PURPOSE: To assess the feasibility of DKI in human lungs and to compare its diagnostic value with standard DWI in differentiating malignancies from benign pulmonary nodules. MATERIAL AND METHODS: Thirty-five pulmonary nodules in 32 consecutive patients were evaluated by DKI by using 3b-values of 0, 500, and 1000 s/mm2 and conventional DWI with b values of 0 and 800 s/mm2. Two observers independently evaluated and compared diagnostic accuracy of mean kurtosis (MK) and ADC values in differentiating malignancies from benign pulmonary nodules. The intra- and inter-observer repeatability (intra-class correlation coefficient [ICC]) were also assessed for each derived measures. RESULTS: The diagnostic accuracy, and the area under curve (AUC) in differentiating malignancies from benign pulmonary nodule, were not significantly higher for MK (Obs. 1a: 85.70%, 0.87; Obs. 1b: 80.00%, 0.80; and Obs. 2: 82.80%, 0.91) as compared to ADC (Obs. 1a: 77.14%, 0.81; Obs. 1b: 80.00%, 0.85; and Obs. 2: 77.14%, 0.85 respectively). The intra- and inter-observer agreement (ICC) for malignant and benign lesions was substantial for each reading. CONCLUSION: The initial results of this study indicate the feasibility of DKI in human lungs. However, there was no significant benefit of DKI derived MK values over ADC for malignant and benign pulmonary nodule differentiation.

Effects of Collagen Grafting on Cell Behaviors in BCP Scaffold with Interconnected Pore Structure.

BACKGROUND: This study was to investigate the effect of collagen grafted porous biphasic calcium phosphate (BCP) on cell attachment, proliferation, and differentiation. Porous BCP scaffolds with interconnected micropore structure were prepared with were prepared and then grafted with a collagen type I. The hydroxyapatite (HA) and ß-tricalcium phosphate (TCP) ratio of the TCP scaffolds was about 60/40 and the collagen was crosslinked on the TCP scaffold surface (collagen-TCP). RESULTS: The sintered BCP scaffolds showed fully interconnected micropore structures with submicron-sized grains. The collagen crosslinking in the scaffolds was conducted using the the N-(3-Dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride and N-hydroxysuccinimide (NHS) crosslinking method. The cell proliferation of collagen-BCP scaffolds showed a similar result to that of the BCP scaffolds. However, osteoblastic differentiation and cell attachment increased in the collagen-BCP scaffolds. CONCLUSIONS: Collagen-BCP scaffold improved the cell attachment ability in early phase and osteoblastic differentiation.

Application of magnetic resonance imaging in cervical spondylotic myelopathy.

Cervical spondylotic myelopathy (CSM) is the most common cause of spinal cord dysfunction and is caused by static or dynamic repeated compression of the spinal cord resulting from degenerative arthritis of the cervical spine and some biological injuries to the cervical spine. The T2 signal change on conventional magnetic resonance imaging (MRI) is most commonly associated with neurological deficits. Diffusion tensor imaging and MR spectroscopy show altered microstructure and biochemistry that reflect patient-specific pathogenesis and can be used to predict neurological outcome and response to intervention. Functional MRI can help to assess the neurological functional recovery after decompression surgery for CSM.

Effect of osteoconductive hyaluronate hydrogels on calvarial bone regeneration.

BACKGROUND: Without exploitation of possibly immunogenic and carcinogenic bone morphogenetic protein, we developed simple but clinically feasible artificial bone graft using osteoconductive hyaluronate (HA) hydrogels and bioactive MegaGen synthetic bone (MGSB). METHODS: HA hydrogels were synthesized by the crosslinking reaction between carboxyl groups of HA and amine groups of gelatin (GEL). Then, artificial bone grafts were prepared by mixing MGSB with HA-GEL hydrogels. The bone regeneration by the MGSB/HA-GEL hydrogel complex was assessed in the skull of New Zealand white male rabbits in 4 and 8 weeks. RESULTS: HA hydrogels were synthesized by the crosslinking reaction between carboxyl groups of HA and amine groups of gelatin (GEL). Then, artificial bone grafts were prepared by mixing MGSB with HA-GEL hydrogels. In vitro proliferation of preosteogenic cells was enhanced with increasing molecular weight of HA. In addition, histological analysis of dissected tissues with hematoxylin and eosin staining confirmed the effective in vivo bone regeneration by the MGSB/HA-GEL hydrogel complex. The MGSB/HA-GEL hydrogels were well resorbed and partially substituted to the lamellar bone after implantation for 8 weeks. CONCLUSIONS: The novel artificial bone graft of MGSB/HA-GEL hydrogel complex for effective bone regeneration might be clinically feasible for further development.

[Protective effect of oxiracetam on traumatic brain injury in rats].

OBJECTIVE: To study the role of oxiracetam on traumatic brain injury in rats. METHODS: Thirty Wistar rats were randomly divided into 3 groups: sham operation group, model group and treatment group. Feeney method were used to establish traumatic brain injury (TBI) model in rats in model and treatment group, and rats in sham group were only broached without hydraumatic fitted. Rats in treatment group were successive administration for 21 days with oxiracetam (100 mg/kg, ig). Neurologic impairment scores were undertook after operation of 1 d, 4 d, 7 d, 14 d and 21 d, and Morris water maze test were proceeded during 15 to 19 days after operation. Average escape latency, searching time in target quadrant and number of crossing target platform in rats were recorded. RESULTS: Neurologic impairment scores of rats in treatment group were significantly less than those of model group after operation of 7, 14 and 21 d (P < 0.05). Average escape latency of model group were significantly higher than those of sham operation group and treatment group (P < 0.05, P < 0.01). Searching time in target quadrant and number of crossing target platform of model group were lower than those of sham operation and treatment group (P < 0.05)). CONCLUSION: Oxiracetam could decrease neural injury and increase ability of learning, memory and space cognition in traumatic brain injury rats.

The cytocompatibility and osseointegration of the Ti implants with XPEED® surfaces.

OBJECTIVES: This study evaluated cytocompatibility and osseointegration of the titanium (Ti) implants with resorbable blast media (RBM) surfaces produced by grit-blasting or XPEED(®) surfaces by coating of the nanostructured calcium. MATERIAL AND METHODS: Ti implants with XPEED(®) surfaces were hydrothermally prepared from Ti implants with RBM surfaces in a solution containing alkaline calcium. The surface characteristics were evaluated by using a scanning electron microscope (SEM) and surface roughness measuring system. Apatite formation was measured with SEM after immersion in modified-simulated body fluid and the amount of calcium released was measured by inductively coupled plasma optical emission. The cell proliferation was investigated by MTT assay and the cell attachment was evaluated by SEM in MC3T3-E1 pre-osteoblast cells. Thirty implants with RBM surfaces and 30 implants with XPEED(®) surfaces were placed in the proximal tibiae and in the femoral condyles of 10 New Zealand White rabbits. The osseointegration was evaluated by a removal torque test in the proximal tibiae and by histomorphometric analysis in the femoral condyles 4 weeks after implantation. RESULTS: The Ti implants with XPEED(®) surfaces showed a similar surface morphology and surface roughness to those of the Ti implants with RBM surfaces. The amount of calcium ions released from the surface of the Ti implants with XPEED(®) surfaces was much more than the Ti implants with RBM surfaces (P < 0.05). The cell proliferation and cell attachment of the Ti implants showed a similar pattern to those of the Ti implants with RBM surfaces (P > 0.1). Apatite deposition significantly increased in all surfaces of the Ti implants with XPEED(®) surfaces. The removable torque value (P = 0.038) and percentage of bone-to-implant contact (BIC%) (P = 0.03) was enhanced in the Ti implants with XPEED(®) surfaces. CONCLUSION: The Ti implants with XPEED(®) surfaces significantly enhanced apatite formation, removal torque value, and the BIC%. The Ti implants with XPEED(®) surfaces may induce strong bone integration by improving osseointegration of grit-blasted Ti implants in areas of poor quality bone.

Comparative study on the cellular activities of osteoblast-like cells and new bone formation of anorganic bone mineral coated with tetra-cell adhesion molecules and synthetic cell binding peptide.

PURPOSE: We have previously reported that tetra-cell adhesion molecule (T-CAM) markedly enhanced the differentiation of osteoblast-like cells grown on anorganic bone mineral (ABM). T-CAM comprises recombinant peptides containing the Arg-Gly-Asp (RGD) sequence in the tenth type III domain, Pro-His-Ser-Arg-Asn (PHSRN) sequence in the ninth type III domain of fibronectin (FN), and the Glu-Pro-Asp-Ilu-Met (EPDIM) and Tyr-His (YH) sequence in the fourth fas-1 domain of ßig-h3. Therefore, the purpose of this study was to evaluate the cellular activity of osteoblast-like cells and the new bone formation on ABM coated with T-CAM, while comparing the results with those of synthetic cell binding peptide (PepGen P-15). METHODS: To analyze the cell viability, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay was performed, andto analyze gene expression, northernblot was performed. Mineral nodule formations were evaluated using alizarin red stain. The new bone formations of each group were evaluated using histologic observation and histomorphometrc analysis. RESULTS: Expression of alkaline phosphatase mRNA was similar in all groups on days 10 and 20. The highest expression of osteopontin mRNA was observed in the group cultured with ABM/P-15, followed by those with ABM/T-CAM and ABM on days 20 and 30. Little difference was seen in the level of expression of collagen type I mRNA on the ABM, ABM/T-CAM, and ABM/P-15 cultured on day 20. There were similar growth and proliferation patterns for the ABM/T-CAM and ABM/P-15. The halo of red stain consistent with Ca(2+) deposition was wider and denser around ABM/T-CAM and ABM/P-15 particles than around the ABM particles. The ABM/T-CAM group seemed to have bone forming bioactivity similar to that of ABM/P-15. A complete bony bridge was seen in two thirds of the defects in the ABM/T-CAM and ABM/P-15 groups. CONCLUSIONS: ABM/T-CAM, which seemed to have bone forming bioactivity similar to ABM/P-15, was considered to serve as effective tissue-engineered bone graft material.

Synchrotron X-ray bioimaging of bone regeneration by artificial bone substitute of MegaGen Synthetic Bone and hyaluronate hydrogels.

Synchrotron X-ray bioimaging was successfully carried out to observe bone regeneration by a novel artificial bone substitute of bioactive MegaGen Synthetic Bone (MGSB) and hyaluronate (HA) hydrogels. A biphasic calcium phosphate of MGSB was prepared by chemical precipitation method, with a porous spherical morphology. On the basis of the fact that HA plays important roles in bone regeneration and promotes the differentiation, vascularization, and migration of stem cells, HA-cystamine (CYS) hydrogels with cleavable disulfide linkages were prepared to supply HA continuously for effective bone regeneration by their controlled degradation in vivo. Among seven different samples using Bio-OSS®, MGSB, and/or several kinds of HA hydrogels, MGSB/HA-CYS hydrogels resulted in the most significant bone regeneration in the calvarial critical bone defect of New Zealand white rabbits. Histological and histomorphometric analyses revealed that the bone regeneration by MGSB/HA-CYS hydrogels was as high as 43%, occupying 71% of the bone defect area with MGSB in the form of a calvarial bone plate in 4 weeks. After that, MGSB was bioabsorbed and replaced gradually with regenerated bones as observed in 8 weeks. Synchrotron X-ray imaging clearly confirmed the effective bone regeneration by MGSB/HA-CYS hydrogels, showing three-dimensional micron-scale morphologies of regenerated bones interconnected with MGSB. In addition, sequential nondestructive synchrotron X-ray tomographic analysis results from anterior to posterior of the samples were well matched with the histomorphometric analysis results. The clinically feasible artificial bone substitutes of MGSB/HA-CYS hydrogels will be investigated further for various bone tissue engineering applications using the synchrotron X-ray bioimaging systems.

Guided bone regeneration by poly(lactic-co-glycolic acid) grafted hyaluronic acid bi-layer films for periodontal barrier applications.

A novel protocol for the synthesis of biocompatible and degradation controlled poly(lactic-co-glycolic acid) grafted hyaluronic acid (HA-PLGA) was successfully developed for periodontal barrier applications. HA was chemically modified with adipic acid dihydrazide (ADH) in the mixed solvent of water and ethanol, which resulted in a high degree of HA modification up to 85 mol.%. The stability of HA-ADH to enzymatic degradation by hyaluronidase increased with ADH content in HA-ADH. When the ADH content in HA-ADH was higher than 80 mol.%, HA-ADH became soluble in dimethyl sulfoxide and could be grafted to the activated PLGA with N,N'-dicyclohexyl carbodiimide and N-hydroxysuccinimide. The resulting HA-PLGA was used for the preparation of biphasic periodontal barrier membranes in chloroform. According to in vitro hydrolytic degradation tests in phosphate buffered saline, HA-PLGA/PLGA blend film with a weight ratio of 1/2 degraded relatively slowly compared to PLGA film and HA coated PLGA film. Four different samples of a control, OSSIX(TM) membrane, PLGA film, and HA-PLGA/PLGA film were assessed as periodontal barrier membranes for the calvarial critical size bone defects in SD rats. Histological and histomorphometric analyses revealed that HA-PLGA/PLGA film resulted in the most effective bone regeneration compared to other samples with a regenerated bone area of 63.1% covering the bone defect area.