Microscopic morphology observation of fracture healing process promoted by panax notoginseng saponins / Observación microscópica de la morfología del proceso de curación de fracturas promovida por panax notoginseng saponins

SUMMARY: The aim of this study was to explore promoting effect of external applying Panax Notoginseng Saponins (PNS) on fractures. For this analysis 18 New Zealand male rabbits were divided into control group, splintage group and PNS group. All rabbits were performed left radius fractures and natural healing, splintage healing and splintage coated with PNS healing. 2 rabbits in each group were sacrificed on day 14, day 28 and day 42 after surgery, separately. Atomic force microscope scanning and nanoindentation tests were performed on the callus sections. The particle size and roughness in PNS group was both less than that in splintage group. The elastic modulus of callus in PNS group was consistent with normal bone tissue started from day 28 after surgery, two weeks earlier than that in splintage group. PNS could significantly reduce fracture healing time and increase strength of callus.

RESUMEN: El objetivo de este estudio fue evaluar el efecto de la aplicación externa de Panax Notoginseng Saponins (PNS) en fracturas óseas. Se usaron 18 conejos machos de raza Nueva Zelanda divididos en grupos control, entablillado y PNS. Se realizaron fracturas del radio izquierdo y cicatrización natural en todos los animales, además de la cicatrización con entablillado y entablillado recubierto con PNS. Se sacrificaron, posterior a la cirugía, dos conejos de cada grupo los día 14, 28 y 42. Se realizaron pruebas de escaneo con microscopio de fuerza atómica y nanoindentación en las secciones de callos. El tamaño de la partícula y la rugosidad en el grupo de PNS fue menor que en el grupo entablillado. El módulo elástico del callo en el grupo de PNS fue consistente con el tejido óseo normal iniciado el día 28 después de la cirugía, dos semanas antes que en el grupo de entablillado. El PNS podría redu- cir significativamente el tiempo de curación de la fractura y aumentar la fuerza del callo.

Mechanical Properties of Calcification from Human Aortic Valve / 医用生物力学

Objective To measure mechanical properties of calcified tissues from human aortic valve by nanoindentation test. Methods Leaflets from 5 patients with aortic stenosis were collected. Elastic modulus and hardness of the calcified leaflets were obtained by nanoindentationtest. Results The elastic modulus and hardness of the calcified leaflets were (15.69±3.89) GPa and (0.59±0.15) GPa, respectively. Conclusions The elastic modulus and hardness of the calcified valve tissues can be obtained by nanoindentationtest, which provides experimental data for biomechanical research of the valve.

The effects of v?tal dyes on mechan?cal propert?es of the human anter?or lens capsule

Purpose: The purpose of this study was to evaluate the mechanical effects of vital dyes on the anterior lens capsule via the nanoindentation method. Methods: Twenty anterior lens capsules of 20 different patients were dissected into four equal fragments. Each fragment was stained separately with dyes for intraocular surgeries, such as trypan blue 0.06% (TB), brilliant blue 0.025% (BB), and indocyanine green 0.05% (ICG), for 1 min. The remaining fragment was assessed as an untreated control group. The alterations on the mechanical characteristics of the anterior lens capsule were evaluated using a nanoindentation testing device with Oliver朠harr and Martens hardness methods. Results: The mean values of elasticity were 7.842 � 0.55 GPa for capsules fragments stained with TB (P < 0.05), 8.407 � 0.82 GPa for capsules fragments stained with BB (P < 0.05), 8.557 � 0.60 GPa for ICG (P < 0.05), and 6.09 � 0.57 GPa for the untreated control group. The mean values of stiffness were 299.7 � 47 MPa for TB (P < 0.05), 317.9 � 34 MPa for BB (P < 0.05), 331.8 � 48 MPa for ICG (P < 0.05), and 229.85 � 44 MPa for the untreated control group. The elasticity of the capsules statistically decreased in comparison to the control group, and the capsule stiffness showed a statistically significant increase in comparison to the untreated controls. Conclusion: The mechanical characteristics of the human anterior lens capsule were affected in association with the alterations in the elasticity and stiffness properties of the capsule as a result of exposure to three different dyes.

Evaluation of the elastic modulus of Beagle's periodontal ligament with nanoindentation technology / 实用口腔医学杂志

Objective: To evaluate the elastic modulus of Beagle's periodontal ligament(PDL) by means of nanoindentation, and to help build constitutive model of PDL precisely. Methods: 24 cross sections were obtained from the tooth root of lower first molars of beagle dog. With nanoindentation, intrusion and unloading to PDL sites on different planes of long axial and in different directions on the same plane of tooth root were achieved, and the load-displacement curves were obtained, from which the elastic modulus was calculated and analyzed. Results: The elastic modulus of the beagle's periodontal ligament varied from 0. 452-1. 542 Mpa. There was no significant difference in elastic modulus of the beagle's lower first premolar PDL in relation to different planes of long axial, while significant difference was found in different directions (buccal/lingual sides and mesial/distal sides) on the same plane of tooth root(P＜ 0. 05). Conclusion: There was a difference in the elastic modulus of periodontal ligament in buccal/lingual sides and mesial/distal sides of the same tooth root.

Effect of Ibandronate and hPTH on the Viscoelastic Response of Ovariectomized Rat Femur / 대한골다공증학회지

PTH and ibandronate are proven to be effective in reversing negative effects of postmenopausal osteoporosis in terms of bone architecture and density. However, the changes of viscoelastic properties of the bone during the pathogenesis of osteoporosis and its treatment were seldom studied. Thus, this study aimed at studying the viscoelastic changes in PTH and ibandronate treated ovariectomized rat to assess the efficacy of the treatments. In this study, distal femurs of twenty-two female rats from four different groups (SHM, OVX, PTH and IBN) were evaluated using CT, pQCT and nanoindentation tests. While density parameters were well preserved in ibandronate treated group, elastic modulus and hardness were found to be better in PTH treated group. Thus, cortical and trabecular bone could be differentially affected by these two categories of drug, due to their difference in the action of mechanism. Moreover, viscosity of the cortical bone showed a positive correlation (R(2)=0.72) with bone strength predictor SSIy, which would possibly correlate with fracture risk.

Measurement of articular cartilage in water based on nanoindentation method / 医用生物力学

Objective To study mechanical properties of the microstructure of the articular cartilage with biological activity by nanoindentation tests under the condition of keeping the articular cartilage in water. Methods The different abilities to keep in situ mechanical properties of the articular cartilage with cold mosaic method or with moisturizing method were evaluated by experiments, and the mechanical properties of the microstructure of the articular cartilage in different kinds of solution used in moisturizing method were also obtained. Results The experiment showed that the elastic modulus on the cartilage surface layer with cold mosaic method was much higher than that with moisturizing method, and the elastic modulus on the cartilage surface and deep layer in chitosan and saline were much lower than that in distilled water. Conclusions The moisturizing method is better at preserving in situ mechanical properties and biological activity of the biological materials, and chitosan and saline are proved to have the effect of keeping mechanical properties of the cartilage used in moisturizing method.

Comparison of the elastic modulus among three dentin adhesives before and after thermocycling / 대한치과보존학회지

The purpose of this study was to determine the effects on the elastic moduli of the adhesive and the hybrid layer from thermocycling. Twenty one human molars were used to create flat dentin surfaces. Each specimen was bonded with a light-cured composite using one of three commercial adhesives (OptiBond FL [OP], Clearfil SE Bond [CL], and Xeno III [XE]). These were sectioned into two halves and subsequently cut to yield 2-mm thickness specimens; one specimen for immediate bonding test without thermocycling and the other subjected to 10,000 times of thermocycling. Nanoindentation test was performed to measure the modulus of elasticity of the adhesive and the hybrid layer, respectively, using an atomic force microscope. After thermocycling, XE showed a significant decrease of the modulus in the adhesive layer (p < 0.05). Adhesives containing hydrophilic monomers are prone to hydrolytic degradation. It may result in the reduced modulus of elasticity, which leads to the mechanically weakened bonding interface.

NANOELASTIC PROPERTIES OF THE DISC, ARTICULAR CARTILAGE AND MANDIBLE FROM HUMAN TEMPOROMANDIBULAR JOINT(TMJ) / 解放军医学杂志

The aim of the study is to determine the characteristics of the material properties of various structures in the temporomandibular joint (TMJ) and the mandibular bone tissues in nanoscopic scale. Using the atomic force microcopy (AFM) with the nanoindentation method, the nanomechanical properties of 6 discs, condylar cartilages and fossate cartilages in the TMJ, and 6 cortical and cancellous bones in the mandible of 3 normal adult men, were measured and analyzed. Results showed that marked differences were found in elastic properties among the different regions of the disc, articular cartilage in the TMJ. In the distribution of elastic modulus in these various structures, the elastic modulus was higher in the anterior and medial regions and lower in the middle, posterior and lateral regions. Otherwise, elastic modulus of the cortical bone in the mandible was approximately 2 times more than the cancellous bone. Elastic modulus in the buccal bone tissues of the mandible was more distinctly below one of the lingual site. The results suggested that the disc, condylar cartilage and fossate cartilage in the TMJ and the cortical and cancellous bone in the mandible were inhomogeneous with the nanolevel measurement. Different structures or various regions in the same structure were loaded by different local mechanical forces in the nanoscale.