ABSTRACT
Objective:To analyze the effects of a novel type of polydopamine (PDA)-coated porous titanium alloy scaffolds loaded with zoledronic acid-gelatin nanoparticles (ZOL-GNPs) for topical sustained drug release on osteoclasts in vitro. Methods:After porous titanium alloy scaffolds were fabricated using electron beam melting technique and ZOL-GNPs with different ZOL concentrations (0, 1, 10, 50, 100, 500 μmol/L) were prepared by desolvation method, PDA-coated porous titanium alloy scaffolds loaded with ZOL-GNPs were constructed by combining the two. The characteristics of the scaffolds were analyzed. The biomechanics of 3 different scaffolds (bare porous titanium alloy scaffolds, PDA-coated porous titanium alloy scaffolds, and PDA-coated porous titanium alloy scaffolds loaded with ZOL-GNPs) were investigated. Drug release detection was carried out by high performance liquid chromatography on the 1st, 4th, 7th, 14th, 21st, and 28th days respectively. The osteoclasts were inoculated into the novel scaffolds with different ZOL concentrations. The expression of osteoclast-related genes was detected by real-time quantitative (RT)-polymerase chain reaction (PCR); the expression of osteoclast-related proteins was detected by Western-blot.Results:The PDA-coated porous titanium alloy scaffolds loaded with ZOL-GNPs were successfully constructed. Electron microscope scanning showed that the GNPs were well spheroidized, smooth in surface, and uniformly dispersed, with a particle size of (243.6±63.4) nm. The ZOL-GNPs were uniformly compounded on the surface and in the pores of the scaffolds, and the spheres were regular in shape with no adhesion. The biomechanical experiments showed that the elastic moduli of the porous titanium alloy scaffolds under 3 different conditions were (1.81±0.12) GPa, (1.80±0.23) GPa and (1.81±0.15) GPa, showing no significant difference ( P> 0.05). The drug release percentage in the porous titanium alloy scaffolds was obviously high on the first day, and increased gradually and slowly in the subsequent 27 days. In the scaffolds with a low concentration ZOL, more osteoclasts adhered and proliferated; in the 50 μmol/L scaffolds, spheroid cells appeared; the spheroid cells increased and even apoptosis occurred with an increase in the ZOL concentration. RT-PCR showed that the expression of Ctsk gene and TRAP gene increased with the increased ZOL concentration, peaked in the 50 μmol/L scaffolds, and then decreased with the increased concentration, showing statistically significant differences ( P < 0.05). Western-blot showed that the expression pattern of Ctsk and TRAP was similar to that of their related genes. Conclusions:The novel PDA-coated porous titanium alloy scaffolds loaded with ZOL-GNPs demonstrate good mechanical properties and an anti-osteoporosis effect via their topical sustained drug release. The scaffolds with a ZOL concentration of 50 μmol/L may exert the best effect on inhibition of osteoclasts.
ABSTRACT
Objective To investigate the changes of plantar pressure distributions and risk of falling before and after the occurrence of neurogenic intermittent claudication (NIC) in patients with central lumbar spinal stenosis (LSS), so as to provide theoretical and data references for the application of plantar pressure analysis in judgment of walking abilities for LSS patients. Methods Twelve patients with LSS at the L4-5 segment were selected as the LSS group, while twelve healthy adults at the same age were selected as the control group. Footscansystem was used to measure plantar pressure of these subjects during walking. Contact area percentage of the total foot contact area (CA%), pressure-time integral (PTI), foot progression angle (FPA), contact time percentage of the stance time (CT%) and total stance time (CT) in both LSS group and control group were compared to evaluate changes of plantar pressures during walking．Results Before the occurrence of NIC, compared with the control group, the LSS group had lower CT% during the forefoot push-off phase (FFPOP) and higher CT% during the initial contact phase (ICP), the total CT and FPA also increased, and the PTI of the 1st-3rd metatarsals and the CA% of the 2nd and 3rd metatarsals were higher. After the NIC occurred, for LSS group, CT% during ICP and forefoot contact phase (FFCP) decreased, CT% during the foot flat phase (FFP) and FFPOP as well as total CT and FPA increased, the PTI and CA% increased in 1st-4th metatarsals. Moreover, the CA% also increased in toe zone, both the PTI and CA% decreased in heel zone. Conclusions In patients with central LSS during walking, the distribution of plantar pressure shifts forward, with abnormal phase of the stance time occurring. Such abnormality will be further aggravated by NIC, indicating a higher risk of falling.
ABSTRACT
With the development of science and technology and the progress of society, the application of a se-ries of new theories, new technologies and new materials makes surgeons' skills improve. But due to the limitations of technological development, public cognition and regulations construction, current surgeons have a variety of helplessness and still face many problems that need to be solved urgently. The solution of these problems needs not only the perfection and progress of the surgeons, but also the understanding and inclusion of the society as well as the perfection and implementation of the policies and regulations. Only with the cooperation of all sides, it can give full play to surgeon' s ability, reduce the surgeon' s helplessness, make the doctor-patient relationship more har-monious, and promote the healthy development of medical and health services.
ABSTRACT
Objective: To investigate mandibular movement characteristics in patients with skeletal class Ⅲ malocclusion during chewing different foods. Methods: 14 skeletal class Ⅲ adult patients with mandibular asymmetry, 10 patients without mandibular asymmetry and 10 normal control cases were chosen to find out the different condylar and incisor movement area ratio based on the aid of ARCUSdigma mandibular moving track analysis system. Results: First,during chewing soft food, the condylar tracing length of skeletal class Ⅲ adult patients with mandibular asymmetry were significant different in sagittal and horizontal plane compared with the other two groups(P<0.05), while the incisor point trajectory difference was not statistically significant. Second, the condylar and incisor movement characteristic showed much more different among three samples during chewing brittle food(P<0.05). Third, in sagittal plane, the deflective condylar movement area ratio was significantly higher than that of the other two groups during chewing hand food(P<0.01). Conclusion: The mandibular movement in skeletal class Ⅲ adult patients are affected obviously by the shape and texture of food. Asymmetric lower mandible patients have a greater preponderance of this phenomenon.