BACKGROUND:Lumbar disc herniation is the most common cause of lumbago in clinic, which seriously affect the patient's daily life, study and work. Therefore, studies on biomechanics of lumbar intervertebral disk benefit to prevent and treat the diseases associated with lumbar intervertebral disk. OBJECTIVE: To summarize the biomechanical progress of lumbar intervertebral disk. METHODS: The first author retrieved China National Knowledge Infrastructure and PubMed database for literatures published from 2009 to 2014. The key words were intervertebral disc, nucleus pulposus, biomechanics, fibrosis annulus, cartilage in Chinese and English, respectively. Articles regarding biomechanical characteristics of lumbar intervertebral disk, nucleus pulposus, fibrosis annulus and cartilage were included, and repetitive studies were excluded. Totaly 5 072 articles were retrieved initialy. In accordance with inclusion and exclusion criteria, 41 articles were included in result analysis. RESULTS AND CONCLUSION:We can fuly understand the pathogenesis, development and adverse consequences of diseases related to the lumbar intervertebral disk by summarizing the structural features and internal pressure of lumbar intervertebral disk and the effect of different loads, biomechanical characteristics of lumbar intervertebral disk with degenerative changes and establishment of mechanical model of lumbar intervertebral disk. It is of directive significance for daily health care of the lumbar intervertebral disk and how to better use force, a physical factor, to solve the lumbar intervertebral disk problems.

Myelodysplastic syndromes ( MDS ) represent a heterogeneous group of clonal hematopoietic disorders with diverse clinical course .Because of the heterogeneity and the lack of molecular markers to monitor disease progression, clinical management of MDS patients is challenging .Recently, with the development of molecular analysis techniques , an increasing number of MDS related molecular biomarkers have been reported.In this review, we will discuss the clinical applications of the newly reported molecular makers in terms of diagnosis , prognosis and treatment.These markers may improve the diagnosis and prognostic assessment systems of MDS , which may potentially be used to guide decision making in the individual therapy.

The mutation status of calreticulin gene (CALR) is helpful for the diagnosis of JAK2 / MPL mutation-negative myeloproliferative neoplasms (MPN), and is closely related to the MPN progression and prognosis.Currently, Sanger sequencing, PCR-fragment analysis, high resolution melting, Taqman RQPCRand the next generation sequencing have been reported to be used to detecting the CALR gene mutations.A proper method for CALR mutation detection and a right laboratory diagnostic procedure according to the MPN-related molecular markers will facilitate the rapid and effective diagnosis and treatment of MPN.

Objective To explore the effects of hypoxia on the growth,mitochondria distribution and function of mouse embryonic fibroblasts(MEFs).Methods MEFs were sub-cultured in the hypoxia group containing 5％ oxygen and normal oxygen group containing 20％ oxygen,every 24 hours,living MEFs were counted by using trypan blue staining.Mito-Tracker Green was used to stain mitochondria,then cells were observed by using laser confocal microscope.The ATP kit was used to detect ATP synthesis.Results During the logarithmic phase,the numbers of living cells in the hypoxia group were higher than those in the normal oxygen group,the differences were statistically significant (P＜0.05).The percentages of perinuclear mitochondrial in the hypoxia group were higher than those in the normal oxygen group,the differences were statistically significant (P＜0.05).Meanwhile,the significant difference was found in the ATP level between the two groups (P＜0.05).Conclusion The distribution of mitochondria in MEFs and energy synthesis are influenced by the hypoxic culture condition,which could be better for promoting cell growth compared with normal oxygen culture condition.

Objective To survey the incidence of acquired adult aplastic anemia (AA) in Shanghai, China. Meanwhile, we compared it with the previous data from China in 1986 and other countries in order to explore the trends. Methods Newly diagnosed AA patients were registered in 6 districts (Jingan, Xuhui, Huangpu, Changning, Putuo, Yangpu ) in Shanghai from 2004 to 2006. Then we calculated the crude and age-adjusted incidence of AA according to the population data from Shanghai Statistic Yearbook. Results There were 38 adult patients with acquired AA. The average crude incidence of AA was 0. 33/100 000 from 2004 to 2006. The incidences per 100 000 persons per year were 0. 40, 0. 14and 0. 64 in 18-34, 35-59 and ≥ 60 years, respectively. The rate of severe AA was 0. 17/100 000.Conclusion The incidence of severe AA has no marked change, but the total rate is a little decreased compared with the data from China in 1986.

Background The application of femtosecond laser in the corneal refractive surgery has made great progression recent years,but the morphology characteristic of corneal stroma surface after making-flap of femtosecond laser is closely concerned.Objective This study was to analyze the influence of photodisrnption of femtosecond laser on the corneal stroma surface and to investigate the effect of different laser pulse energy on the sudace ultrastructure of corneal stroma.Methods Corneal flaps were made with Visu Max femtosecond laser in 16 fresh porcine eyes with the pulse energy 125 nJ,155 nJ and 195 nJ respectively,and Moria-M2 microkeratome was used as control.Scanning electron microscopy (S-3400N Hitachi High-Technologies Corp) was used to observe and compare the ultrastructural characteristic of corneal stroma bed surface after making of corneal flap.Results The corneal strnma was evaporated and created a smooth surface when photodisrnption happened in the femtosecond laser group.Residual tissue bridges could been exhibited among the cavitation bubbles under the scanning electron microscope.Corneal strnma surface was smooth in the 125 nJ pulse energy group,but some tissue bridges still were visible.In the 155 nJ pulse energy group,much more smooth surface was seen without tissue bridges and mechanical damages on the corneal surface.However,the surface quality was worse and many tissue bridges and grooves existed in the 195 nJ pulse energy group.In addition,different sizes of slots caused by big cavitation bubbles were visible with the round and oval shape.The edges were regular and sharp with small damage zone after cutting with femtoseeond laser.However,many elevated fibril tissues could be seen on the corneal surface after making of flap with microkeratome.Many crimp and irregularity tissues were found on the surface.Blunt surface and indentations appeared in the cutting edge.Conclusions The mierostrueture of corneal stroma surface is more smoother after making of corneal flap with fentosecond laser in comparison with microkeratome.Pulse energy of 155 nJ is preferably during the making-flap with femtosecond laser.

OBJECTIVETo investigate the effect of midazolam on human ether-a-go-go (hERG) K+ channels exogenously expressed in human embryonic kidney cells (HEK-293) and the underlying molecular mechanisms.

METHODSWhole-cell patch clamp technique was used to record WT, Y652A and F656C hERG K+ current expressed in HEK-293 cells.

RESULTSMidazolam inhibited hERG K+ current in a concentration-dependent manner, the half-maximum block concentrations (IC50) values were (1.31 ± 0.32) µmol/L. The half-activation voltage (V1/2) were (2.32 ± 0.38) mV for the control and (-1.96 ± 0.83) mV for 1.0 µmol/L midazolam. The half-inactivation voltage (V1/2) was slightly shifted towards negative voltages from (-49.25 ± 0.69) mV in control to (-57.53 ± 0.53) mV after 1.0 µmol/L midazolam (P < 0.05). Mutations in drug-binding sites (Y652A or F656C) of the hERG channel significantly attenuated the hERG current blockade by midazolam.

CONCLUSIONMidazolam can block hERG K+ channel and cause the speed of inactivation faster. Mutations in the drug-binding sites (Y652 or F656) of the hERG channel were found to attenuate hERG current blockage by midazolam.

Dose-Response Relationship, Drug ; Ether-A-Go-Go Potassium Channels ; drug effects ; HEK293 Cells ; Humans ; Midazolam ; pharmacology ; Mutation ; Patch-Clamp Techniques ; Potassium Channel Blockers ; pharmacology

BACKGROUND: It is a key point to revascularize the tissue-engineered bone during the repairing of large bone defect. Fascia flap is commonly used in clinic to accelerate the blood supply of implant.OBJECTIVE: To observe the feasibility of repairing goat tibia defects with tissue-engineered bone and accelerating revascularization with fascia flaps.DESIGN: Randomized and controlled animal experiment SETTING: Department of Traumatic Orthopaedics, Nanfang Hospital,Southern Medical University.MATERIALS: Totally 36 goats with the body mass of 14.5-15.5 kg of either gender were enrolled.METHODS: This experiment was conducted at the Department of Traumatic Orthopaedics, Nanfang Hospital, formerly the First Military Medical University of Chinese PLA from December 1999 and December 2003.Bone and periosteum defects 20 mm long were made and fixed with plate of left tibia in 36 goats. They were randomly divided into four groups: Group A in which the defects were filled with coral hydroxyapatite (CHAP), Group B I CHAP+ bone marrow stroma cells (BMSc); Group C with fascia flaps;Group D with nothing. Next, the bone regeneration and the revasculariza tion were evaluated. Radionuclide bone imaging was done 2, 4, 8 weeks after operation. After X-ray examination, the index of optical density of Xray films and histology of the implants were analyzed at 4, 8, 12 weeks after operation, and the biomechanical characters were studied 12 weeks postoperatively.MAIN OUTCOME MEASURES: Gross observation and X-ray, radionuclide bone imaging, biomechanical and histological observation RESULTS: Totally 36 goats entered the stage of result analysis. ① Gross observation of the repair sample of bone defects of the animals in each group: there was no osteogenesis postoperatively at each time point in the blank control group . In Group B, at week 8 to 12, there was no obvious osteogenesis and callus formation on the surface of the materials. In Group C,At weeks 8 to 12, bone defects were filled gradually, many bone callus processes were seen on the surface of the materials , centralizing and enwrapping the materials. The osteogenetic process in the Group C were superior to that of theGroup B. ②Examination result with -901/SA PET-CT scanners: It was seen by naked eyes that at weeks 2 to 8 in the Group A,the radioactivity concentration at region of interesting (ROI) of the operation side had obvious increasing trend, and similar trend of changing appeared in the Group B and Group C, but the ROI counts and T/NT value in the Group B were both lower than those in the Group C. The decreasing trend in the Group A was lower than that in the Group B. ③) Radiological results: the osteogenesis volume through measuring absorbance in the order from large to small was Group C, Group B, and Group A[At week 12, they were (4.180±0.192), (3.480±0.453), (2.959±0.682)respectively ].④Biomechanical results: there were significant difference of loading and bending stress in the Group C, Group B and Group A [ The loading was (758.333±88.754), (530.214±65.297), (359.667±60.715)N , respectively; and the bending stress was (13.937±2.199), (10.123±1.243),(6.223±0.945)N/mm2, respectively ].⑤)Histological results: Slices at various time points in the blank control group showed no bone tissue. In the other three 3 groups, with the prolongation of time, the osteagenetic range and quality were in the order of Group C, Group B and Group A.CONCLUSION: The fascia flaps can accelerate the revascularization process in the formation of tissue-engineered bone so that the capability of tissue engineered bone to repair the large bone defects may be enhanced.

Objective To investigate the relationship between the disorder of learning and memory in lead rats and the argnine vasopressin (AVP) and the somatotatin (SS) of hippocampus.Methods Sixty healthy 2-month old Sprague-Dawley rats were randomly divided into normal control group and lead group. Normal control group was given deionized water and the lead group was given 0.1% lead acetate deionized water for 3 months to make chronic lead rat. Learning and memory ability was tested by the Y-maze test. The content of AVP and SS in hippocampus were tested by the immunohistochemical method. Results The learning memory ability and the content of AVP and SS in hippocampus CA1 section of the lead group were degraded obviously than the control group(all P0.05)in hippocampus CA3 section of the lead group were degraded also.Conclusion The disorder of the learning and memory of the lead exposure rats may be due to the decrease of the content of AVP and SS in hippocampus.

BACKGROUND:Studies have confirmed that the surface treatment methods such as silane coupling agent and sand blasting could improve bonding strength of zirconia ceramics and resin binder. In addition, the increase of micro cracks on the surface of zirconia ceramics can also improve the bonding strength of zirconia ceramics and resin binder. But there is a lack of related studies addressing whether repeatedly sintering would have an impact on shear bond strength of zirconia ceramics.
OBJECTIVE:To determine the effect of decorative porcelain temperature firing on the shear bond strength between dental zirconia ceramics and resin binder.
METHODS:Twenty pieces of zirconia ceramics specimens were selected from 40 tablets, and then randomly divided into five groups according to the number of sintered times:control group (without sintering), sintering groups for 2, 4, 6, 8 times. Heat starting temperature was 500 ℃, and final temperature was 1 000 ℃ with a heating rate of 55 ℃/min. The vacuum time was 7 minutes. During the sintering, the final temperature was constant. Unsintered ceramic pieces were bonded using resin binder. Universal testing machine was used to test the shear strength of the interface between the two pieces of zirconia ceramics. The interface after shearing was characterized by scanning electron microscope.
RESULTS AND CONCLUSION:The shear strength of sintering groups for 4, 6, 8 times was significantly higher than that of the control group (P<0.05). Shear strength of specimens sintered twice was slightly higher than that of specimens without sintering, but the difference was not significant (P>0.05). Shear strength of specimens sintered 8 times was slightly higher than that sintered 4 and 6 times (P<0.05). Under the scanning electron microscope, there was no crack on the surface of non-sintered zirconia ceramics. After 2 times sintering, the surface appeared to have fine cracks. After sintering 4 times, visible cracks were increased. After six rounds of sintering, the surface began to have significant changes;cracks rose along with slight gaps and a smal amount of adhesive residues were found. After sintering for 8 times, cracks and voids were obviously increased on the sintered surface and adhesive residues were found. It indicated that after sintering for 4, 6 and 8 times, zirconia ceramics could have a good shear strength binding to resin adhesives;with the increasing of sintering times, the shear bond strength could be increased.