Objective To investigate the effects of ischemia reperfusion on the morphological changes of sinoatrial node(SAN) cells in rabbits in vivo . Methods Ninety healthy adult rabbits were randomly divided into 3 groups with 10 rabbits in control and every subgroup: control group [a suture passed under the root section of right coronary artery(RCA) without ligation], ischemia group(occluding the root section of RCA for 10, 30, 60 and 120 min respectively), ischemia reperfusion group(10, 30, 60 and 120 min ischemia after respectively followed by 4 hours′ reperfusion). Results ① Compared with control group, abnormal structure of SAN cells was not seen in 10 min ischemia group and 10 min ischemia reperfusion group with light microscopy, except slight mitochondrial swelling of SAN cells in former group with electron microscopy. ② There were morphological changes of SAN cells in 7, 6 and 8 rabbits in 30, 60 and 120 min ischemia group, presenting mainly as cellular swelling, karyopyknosis, and focal necrosis under a light microscope, and mitochodrial swelling, cristae disorganization or break under an electron microscope. The most severe cellular damages were found in 120 min ischemia group. ③ In ischemia reperfusion group, there were morphological abnormalities of SAN cells in 6, 8 and 7 rabbits in 30, 60 and 120 min ischemia reperfusion groups. The morphologic changes were similar to those in ischemia group, but injury degree was more severe than that in ischemia group with the same ischemic time. Conclusion Ischemia and ischemia reperfusion can induce morphological changes of SAN cells in a time dependent manner in rabbits in vivo , and the injury degree is more severe in ischemia reperfusion group than that in ischemia group with the same ischemic time.

Objective To explore the regularity of dynamic morphologic changes of the sinoatrial node (SAN) cells of rabbits after the constitution was damaged by formaldehyde wet dressing. Methods Sixty rabbits were randomly divided into 6 groups (n=10 in each group): the control group and 5 experimental groups observed at 2 h, 1, 2, 3, and 4 weeks respectively after the operation. The SAN constitution of rabbits was damaged by 20% formaldehyde wet dressing. The constitutions of SAN were cut quickly at 2 h after wet dressing in the control group and at the corresponding time points in other experimental groups respectively. The specimens were made for light microscopical and electron microscopical observations. The apoptosis of SAN cells was detected by TUNEL method. Results Compared with those in the control group, SAN cells in all experimental groups were damaged at various degrees observed by light microscopy and electron microscopy. Distinct cell tumefaction, soak of grain cells, cytoclasis, hyperplasia of collagen fibers, and other pathological changes were detected. Electron microscopical observation showed distinct pathological changes of the super-micro construction of cells. Apoptosis was not detected in the control group, but various degrees of apoptosis in all experiment groups. The apoptotic rates in all experimental groups were significant as compared with that in the control group (P

Objective To study the effects of heart ischemia reperfusion on conductive function of atrioventricular node (AVN) in rabbits. Methods Animal models of ischemia reperfusion of AVN were established by ligating and reopening the right coronary artery of rabbits. A total of 60 adult rabbits were divided into control groups ( n =10), right coronary artery occlusion group ( n =10), and ischemia reperfusion groups with ligation of the right artery occlusion for 10, 30, 60 and 120 min respectively ( n =10 for every subgroup). The hemodynamics, His bundle electrography and epicardial electography were carried out and recorded. Results After occlusion of right coronary artery, 94.8% animals in experimental groups were found to have prolonged atrial His interval (AH) ( P

Serum 25-(OH)D3concentration was determined in subjects with different types of obesity. The serum 25-(OH)D3levels in overweight or obese and central obese subjects were lower than that in non-obese subjects.(P＜0.01). In a multiple linear regression analysis serum 25-(OH)D3was independently and negatively correlated with body mass index and waist circumference.

A label-free fluorescent assay for highly sensitive detection of DNA was developed based on structure switch of hairpin DNA probe to a G-quadruplex-based DNAzyme triggered by target DNA. The hairpin DNA probe includes sequences that correspond to the base sequence of the G-quadruplex and to the sequence complementary to the target DNA, respectively. The hairpin structure of the probe DNA is
energetically favored over the G-quadruplex structure in the absence of target DNA, resulting in the protection of the G-quadruplex in an inactive hairpin configuration. The hybridization of target DNA to the loop domain opens the stem of the hairpin, resulting in the self-assembly of the uncaged G-quadruplex structure, which acts as a DNAzymatic label for the signal production and amplification in the presence of hemin. The peroxidase-like DNAzyme oxidizes non-fluoresecnt 10-acetyl-3,7-Dihydroxypenoxa-zin (ADHP) to the florescent product by H2 O2 , giving rise to fluorescence emission. This allowed the utilization of the H2 O2-ADHP fluorescent system for quantitative analysis of DNA. The experimental conditions were optimized as:pH 8. 0, 10 mmol/L K+, 0. 2 μmol/L Hemin, 50 μmol/L ADHP. The assay showed a linear relationship toward target DNA concentration in the range of 5. 0 pmol/L-1. 0 nmol/L, with a limit of detection of 3. 0 pmol/L (S/N=3). The assay exhibited good selectivity against single-base mismatched DNA.

AIM: To study influence of ischemia-reperfusion(IR) on apoptosis and expression of apoptosis-related genes Fas-L, Bax and Bcl-2 of sinoatrial node(SAN) cells in rabbits in vivo. METHODS:Ninety healthy adult rabbits were divided randomly into control group, ischemia groups (I 10 min , I 30 min , I 60 min and I 120 min ) and IR groups (I 10 min R 4h , I 30 min R 4h , I 60 min R 4h and I 120 min R 4h ). IR injury model of SAN was established by occluding and loosening the start section of right coronary artery. The apoptosis of SAN cells was detected by TUNEL staining. The expression of Fas-L, Bax and Bcl-2 of SAN cells was detected by immunohistochemistry. RESULTS:①No obvious apoptosis of SAN cells was observed in control group, I 10 min and I 30 min groups. Apoptosis of different degrees in SAN cells were found in 68.3%(41/60) rabbits in I 60 min , I 120 min and 4 subgroups of IR. ②The highest expression of Fas-L and Bax was observed in I 120 min group and that of Bcl-2 was in I 60 min group. ③The highest expression of Fas-L and Bax was observed in I 60 min R 4h group. The peak level of Bcl-2 was observed in I 30 min R 4h group. ④The expression of Fas-L and Bax was significant higher in IR group than that in ischemic group at the same time point. CONCLUSION:Ischemia and IR induced apoptosis of SAN cells in rabbit in vivo . Fas-L、Bax、Bcl-2 may participate in the regulation of apoptosis and the injury during IR aggravates the apoptosis of SAN cells.

Objective To study the effect of ischemia reperfusion(IR) on electrophysiological function of sinoatrial node(SAN) in rabbits. Methods Ninety healthy adult rabbits were divided randomly into control group, ischemia groups (I) 10(I10 min), 30(I30 min), 60(I60 min) and 120 min(I120 min) and IR groups (10, 30, 60 and 120 min ischemia followed by 4 h reperfusion respectively)(I10 minR4 h, I30 minR4 h, I60 minR4 h and I120 minR4 h). There were 10 rabbits in the control group and each subgroup. IR injury model of SAN was established by occluding and loosening the start section of right coronary artery(RCA). The changes of AA interval and arrhythmia were recorded by electrocardiography and cardiac chamber electrography synchronously. Results ① There was no significant difference in AA interval between different time points in the control group. ② Sinus arrest(SA), sinus bradycardia with arrhythmia(SB), or atrial tachyarrhythmia(AT) were found in 51 rabbits (63.75%) out of 80 rabbits in I and IR groups in ischemic period. The incidence rate of arrhythmia increased in a time dependent manner. The AA intervals also increased by at least 40 ms in 54 rabbits (67.5%). ③ Sinus or atrial arrhythmia during ischemic period was found in 26 out of the 40 rabbits in IR group, but 15 returned normal after reperfusion. ④ Increased AA intervals were found in 27 out of the 40 rabbits in IR group during ischemic period. Most of them recovered to pre occlusion level within 10 min after reperfusion, but the AA intervals prolonged again in I60 minR4 h and I120 minR4 h groups as the reperfusion elongated. Conclusion ① These findings suggest that about 2/3 of the rabbit sinus node arteries may stem from right coronary artery. ② Electrophysiological changes due to ischemia of SAN resemble the electrocardiogram of sick sinoatrial node syndrome. ③ Reperfusion arrhythmia can be induced by reperfusion after a long time of ischemia.

Objective Using the technology of siRNA to inhibit gene expression of T cells'nonreceptor tyrosine protein kinase Lck in asthmatic mice,and to study the effect of siRNA inhibited Lck to the function of T cells in asthmatic mice.Methods The 21 - 23 bp RNA fragments of mouse T cell Lck were made by chemosynthesis.INTERFERinTMsiRNA Transfection Reagent was used as transfection reagent to transfect the siRNA into the spleen T cells of asthmatic mice for 48 hours.Then T cells were mixed with bone marrow dendritic cells (DC) of asthmatic mice for another 48 hours.Cell culture suspension was collected and the level of IL-4,IL-13,IL-2,INF-γ were detected with respondent ELISA kits; Western Blot was used to identify if the expression of Lck was blocked.Results The expression of Lck in T cells almost could not be detected in siRNA interference group.The levels of IL-4 and IL-13 in siRNA interference group( 10.19 ± 1.66,12.34 ±0.79) were lower than no-siRNA interference(28.06 ±2.88,27.87 ± 1.61 )and control group ( 22.07 ± 2.5 1,20.47 ± 2.37 ),and the difference was statistical significant ( P ＜0.01 ).Conclusions Special siRNA could block the expression of special gene,and Lck specific siRNA could block the activation and differentiation of T cells and reduce the secretion of inflammatory cytokines in asthmatic mice.

Objective To establish a new method for measuring the 3-D kinematics of hindfoot joints in vivo by using reverse engineering software together with the theory of rigid body kinematics.Methods CT images were gathered from 9 feet of 5 healthy volunteers in both the initial position (neutral position) and the terminal position (extremely inversion-adduction-dorsiflexion position).The 3-D digital modules of hindfoot joints in the initial position and terminal position were established with MIMICS 10.01 software.The data of reconstructed digital modules was inputted into the GEOMAGIC 10.0 software in STL format for twice registration,and then their relatively displacement and changes of angle in 3-D space between the two positions were calculated Results The rotation range of the tibiotalar joint was 3.89° ±2.77° in eversion,5.29°±4.47° in abduction,10.77°+5.70° in dorsiflexion,and the relative displacement was 0.78±0.59 mm towards lateral ankle,0.18±0.75 mm towards the hindfoot,(0.65±0.71) mm towards the proximal limbs;the range of subtalar joint was 16.46°±2.94° in inversion,12.77°±1.81° in adduction,6.33°±4.32° in plantarflexion,and the relative displacement was 5.50±1.45 mm towards medial ankle,1.96±1.77 mm towards forefoot,0.43±1.18 mm towards distal limbs; the range of talonavicular joint was 38.82°±5.98° in inversion,19.71°±6.33° in adduction,5.09°±6.89° in plantarflexion,and the relative displacement was (9.77±1.73) mm towards medial ankle,3.13±1.29 mm towards hindfoot,4.64±1.42 mm towards proximal limbs.Conclusion This method measuring 3-D kinematics of hindfoot joints in vivo is non-invasive and easy to operate.

Objective To investigate the feasibility and efficiency of unilateral pedicle screw combined with contralateral translaminar facet screw fixation by percutaneous and interbody fusion to treat low lumbar vertebra diseases. Methods Thirty patients with low lumbar vertebra diseases were entered into the study, including 8 males and 22 females with an average age of 53.7 years. All patients underwent discectomy, spinal canal decompression, cage implantation and lumbar fixation by unilateral pedicle screw combined with contralateral translaminar facet screw under gunsight guiding by percutaneous. Clinical outcomes were assed by JOA questionnaires before and after operation. Operative time, blood loss, and postoperative draiming were recorded. Radiological examination was obtained to assess position of translaminar facet screw.Results Mean operation time was 89 min with a blood loss of 285 ml. Position of translaminar facet screw grade Ⅰ were 24 cases, and grade 11 were 6. Mean follow-up was 22.5 months. 29 cases got bony fusion, and the fusion rate was 96.7%. There were no instability and evidence instrument failure during follow-up. The JOA grades improved from 13.0 preoperation to 25.2 at final follow-up, with the excellent and good rate of 72.5 %. Conclusion Unilateral pedicle screw combined with contralateral translaminar facet screw fixation by percutaneous and interbody fusion provide simple procedure, little trauma, forceful fixation, high fusion rate, and less complication, etc. Therefore, the surgical maneuver is a good choice for partial low lumbar vertebra diseases.