Correlation analysis between rotator cuff tear and the superior migration of humeral head / 北京大学学报(医学版)

OBJECTIVE@#To evaluate the association between rotator cuff tear and the proximal migration of humeral head.@*METHODS@#In this research, we retrospectively selected 30 patients with unilateral rotator cuff tear in Peking University People's Hospital from September 2015 to May 2016, who received magnetic resonance imaging (MRI) and X-ray of the painful shoulder before enrollment in this study, the duration between the two examinations was no longer than 1 week, and also there was no past history of surgery in the selected shoulders. There was no other exclusion criteria. Upward migration index (UMI) was the ratio between the distance of humeral head center to the lower surface of acromion, and the radius of humeral head circle, which could help to minimize the effect of anatomy difference and imaging magnification, compared with the traditional acromiohumeral distance (AHD). Then we introduced this index to stratify the selected 30 patients into 3 groups, and each group contained 10 patients, UMI of group 1 was >1 and ≤1.2, UMI of group 2 was >1.2 and ≤1.4, UMI of group 3 was >1.4. As the supraspinatus was most commonly affected by pathological change among the four rotator cuff tendons, we took it as the research object. Then we used the Spearman correlation analysis to evaluate the relationship between UMI and fatty degeneration, rotator cuff tear size and the thickness of ruptured supraspinatus tendon from X-ray and MRI.@*RESULTS@#In the A-P view, the average UMI was 1.33 (1.02-1.51, SD: ±0.22). UMI and the tear size had a significant negative correlation (R=-0.584, P<0.01), and also there was a negative correlation between the fatty degeneration of the supraspinatus (R=-0.312, P=0.033). However, there was no correlation between UMI and the thickness of ruptured supraspinatus (R=0.127, P=0.071).@*CONCLUSION@#UMI is related with the fatty degeneration of supraspinatus and the tear size. The reduction of UMI is a predictable and reliable mark of rotator cuff tear and degeneration in clinic. Physicians can use physical examination and X-ray first when facing the patients with shoulder pain, which is convenient and helpful for evaluating rotator cuff tears.

Construction of serum-resistant cationic polymer α-CD-PAMAM and evaluation of its performances as gene delivery vector / 药学学报

Polyamidoamine (PAMAM) dendrimers as synthetic gene vectors are efficient gene delivery systems. In this study, a kind of α-cyclodextrin-PAMAM conjugates polymer (CyD-G1) was synthesized as a gene delivery vector. Based on 1H NMR detectation, about 6.4 PAMAM-G1 molecules was grafted onto an α-CD core. Agarose gel electrophoresis revealed that CyD-G1 could efficiently bind with DNA to condense them into nano-scale particles, which showed a similar binding capacity of PEI-25K. Besides, it could protect DNA from DNase I degradation in a low N/P ratio. When N/P ratio in the CyD-G1/DNA polyplex was 40, the average particle size of CyD-G1/DNA polyplex was about 120 nm, and zeta potential was +21 mV. This polyplex could maintain its particle size in serum-containing solution within 360 min. In comparison with PEI-25K carrier, CyD-G1 showed low cytotoxicity in various cell lines. Cell transfection results showed that CyD-G1 efficiently delivered DNA into cells at N/P=80 compared with Lipofectamine 2000 and PEI-25K.Unlike Lipofectamine 2000 and PEI-25K, in serum-containing test condition, CyD-G1/DNA polyplex could maintain the transgene activities. The results of confocal laser scanning microscopy indicated that most DNA entered into cell nuclei within 4 h, and this phenomenon was consistent with the results calculated by flow cytometry. Taken together, CyD-G1 showed good transgene activities and the gene delivery vector could be used not only in vitro but also in vivo.

Folic acid modified polyrotaxanes effectively transfer siRNA-CD47 to inhibit the proliferation of melanoma / 药学学报

To investigate the effect that folic acid-modified polyrotaxanes (FPP) transfered siRNA CD47 to inhibit melanoma proliferation, the expression of CD47 in clinical melanoma patients was tested by Western blot and RT-PCR, respectively. Physical performance of FPP (siRNA-CD47:CD47) nanoparticles was tested by Malvern particle size instrument and scanning electron microscope. The clone formation experiment demonstrated that FPP (CD47) nanoparticles inhibited the growth of clones. Invasion assay revealed that FPP (CD47) inhibited migration of B16F10 cells. Tumor bearing mice were used in the experiment to test the efficacy of FPP (CD47) treatment. Compared with the control group, high expression of CD47 was observed in the clinical melanoma patients. FPP (CD47) nanoparticle size at 80 nm exhibited a potential of 10 mV; compared with FPP (Con), fluorescence intensity was significantly reduced to 4.2% and B16F10 cell clone formation was decreased by 91% in the FPP (CD47) treatment. Tumor volume of tumor-burdened mice was decreased by 90% with FPP (CD47) treatment. FPP (CD47) lowered CD47 protein and mRNA expression in the tumor. This study suggests that FPP may transfer siRNA CD47 into the cancer cells to inhibit melanoma growth effectively.

Case-control study on effects of fracture of processus styloideus ulnae on prognosis after plate fixation for the treatment of distal radial fractures / 中国骨伤

<p><b>OBJECTIVE</b>To analyze effects of fracture of processus styloideus ulnae on prognosis in the treatment of distal radial fracture of type C according to AO classification.</p><p><b>METHODS</b>This was a retrospective case-control study, and the information was got ten through case evaluation and follow-up, including sex, age, patient satisfaction, Gartland & Werley score and radiographic score. There were 76 patient treated with open reduction and plate fixation in People's Hospital Affiliated to Peking University from July 2006 to July 2011. All the patients were divided into two groups: no combination with fracture of processus styloideus ulnae (group A, 56 cases), combination with fracture of processus styloideus ulnae (group B, 20 cases). The patients in group A and B were treated with open reduction and internal fixation; however the fracture of processus styloideus ulnae was not fixed. The indexes such as clinical data, bone grafting, joint movement, Gartland & Werley score and radiographic score were compared between two groups.</p><p><b>RESULTS</b>The ulnaris pain of patients in group B was more obvious than that in group A. The local VAS, palmar and dorsal flexion degree of wrist joint, motion VAS, patients satisfaction score, radial and ulnar deviation degree, pronation and supination of forearm degree, Gartland & Werley score and radiographic score were separately 0.1 ± 0.1, (51.1 ± 1.9)°, (60.2 ± 1.9)°, 0.6 ± 0.1 (23.1 ± 0.9)°, (28.7 ± 1.3)° (81.5 ± 2.6)°, (68.2 ± 2.7)° 1.9 ± 0.3, 89.6 ± 12.3 in group A; and separately 0.3 ± 0.3, (51.4 ± 2.3)°, (66.6 ± 1.7)°, 0.5 ± 0.2, (24.5 ± 2.0)°, (26.9 ± 1.8)°, (80.3 ± 2.5)°, (70.3 ± 3.7)°, 1.2 ± 0.4, 92.5 ± 7.5 in group B; there were no statistical differences in above indexes between two groups.</p><p><b>CONCLUSION</b>Whether the distal radial fracture with a concomitant unrepaired ulnar styloid fracture or not exerts no influence on mainly outcomes including function, radiography and motion of the wrist.</p>

Clinical effect of distal radius fracture treated with open reduction and internal plate fixation / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>For some specific comminuted unstable intra-articular fracture, the plaster cast can not maintain the alignment of the articular surface effectively. The aim of this study was to evaluate the clinical effects of distal radius fracture treated with open reduction and internal plate fixation retrospectively.</p><p><b>METHODS</b>From January 2002 to March 2010, 539 cases of distal radius fracture were treated with open reduction and internal fixation, including 184 males and 355 females aging 21 - 72 years (mean 57 years). Fractures were caused by falling to the ground in 459 cases, by traffic accident in 62 cases and by athletic injuries in 18 cases. Of 539 cases, there were 523 cases of closed fracture and 16 cases of open fracture. According to Arbeitsgemeinschaft fur Osteosynthesefragen (AO) standards of classification, there were 14 cases of A2 type, 22 of A3 type, 18 of B1 type, 24 of B2 type, 62 of B3 type, 91 of C1 type, 162 of C2 type and 146 of C3 type. The time from injury to operation was 1 - 16 days (mean 5 days). All patitents received open reduction and internal plate screw fixation. Forty-seven patients with bone defect were given 6 - 15 g autologous ilium and 75 cases were given 5 ml calcium sulphate artificial aggregate after reduction.</p><p><b>RESULTS</b>All incisions healed by first intention after operation. Patients were followed up for 15 to 32 months postoperatively (mean 22 months). The fractures healed within 10 - 18 weeks after operation (mean 12 weeks). During the last follow-up, the mean palmar tilt was (7.0 ± 0.9)° and the mean ulnar variance was (21.0 ± 4.2)°, showing significant difference when compared with preoperation ((-5.0 ± 1.2)° and (8.0 ± 3.8)°). The radial heights were not abbreviated. According to Gartland and Werley assessment system, the results were excellent in 314 cases, good in 163 cases, fair in 46 cases, and poor in 16 cases 12 weeks after operation, the excellent and good rate was 88.5%.</p><p><b>CONCLUSIONS</b>The clinical effect of distal radius fracture treated with open reduction and internal plate fixation was relatively satisfactory. Meticulous operation procedure and individual rehabilitation strategy contribute to the wrist joint functional recovery.</p>

Three kind of scoring system for proximal humeral fractures in patients with postoperative functional review of evaluation: a multicenter study / 中华外科杂志

<p><b>OBJECTIVE</b>To evaluate the ASES, Constant and HSS score systems and their significance on postoperative function of the shoulder.</p><p><b>METHODS</b>Totally 172 cases of proximal humeral fracture of five affiliated hospital from September 2004 to September 2008 were analyzed. All the functional outcome of the involved shoulder were evaluated by ASES, Constant, HSS score and patient self score. The correlations and agreement of three shoulder scales were analyzed with Pearson correlation test and Bland-Altman plot in different age groups and fracture types.</p><p><b>RESULTS</b>(1) The Constant score were lower than other two scores in the same age group and fracture type (F = 13.62 and 4.80, P < 0.05). (2) The correlations between three shoulder scales: ASES and Constant (r = 0.754, P = 0.0003), ASES and HSS (r = 0.755, P = 0.0001), Constant and HSS (r = 0.858, P = 0.0002). The correlations between three shoulder scales and patient self evaluation: ASES (r = 0.602, P = 0.0002), Constant (r = 0.705, P = 0.0001), HSS (r = 0.663, P = 0.0037). The Bland-Altman plot shows three shoulder scales have good agreement. (3)The correlation between Constant score and patient self evaluation decreased in the elder group and severe fracture type.</p><p><b>CONCLUSIONS</b>ASES, Constant, HSS shoulder score systems are all fit to evaluate the functional outcome of the shoulder, they have good correlation and agreement. Constant score in recommended for its high correlation coefficient with patient self evaluation score. However, its age bias must be paid attention in clinical practice. ASES shoulder score can be used in remote follow-up.</p>

A new experimental model to study healing process of metaphyseal fracture / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>There are few researches for the healing of metaphyseal fractures; moreover, the animal models to study the metaphyseal fractures are usually made by the oscillating saw osteotomy without reliable fixation, which is not in accordance with our current clinical practice. In this study, we established a new model to observe the healing process of metaphyseal fractures.</p><p><b>METHODS</b>Eighteen New Zealand rabbits were used in the study. The fracture model was created by splitting the medial tibial plateau in rabbits, then reset, and fixed with compression screws. At 1, 2, 3, 4, 6, and 8 weeks postoperatively, the tibial specimens were collected; firstly, a general observation and an X-ray examination of the specimens was done, and then they were embedded in methylmethacrylate and cut into sections with hard tissue slicer. The sections were stained with Giemsa reagent and examined under light microscopy.</p><p><b>RESULTS</b>There was no fracture displacement in the tibial specimens of all time points, except for one showing a collapse. No external callus formation could be observed by X-ray and general examination. After 1 week of the operation, the fracture gap was filled by mesenchymal tissue; 2 weeks postoperatively, a large number of woven bones were formed; from the third week onwards, the woven bone began to turn into lamellar bone, and new trabecular structure began to form. In all of the slices, no obvious chondrocytes formed in fracture areas; thus, there was no endochondral ossification.</p><p><b>CONCLUSIONS</b>This model was an ideal fracture animal model and suitable for the study of metaphyseal fracture healing. The X-ray and histological images demonstrated that metaphyseal fracture healing was a process of direct bone healing through intramembranous bone formation under the conditions of minor trauma, good reduction, and firm fixation.</p>

Clinical features analysis of femoral neck fractures in 219 patients / 中华外科杂志

<p><b>OBJECTIVES</b>To investigate the clinical features of femoral neck fractures and analyze related causes.</p><p><b>METHODS</b>The clinical data of patients with femoral neck fractures from June 2002 to August 2009 were retrospectively analyzed. The gender, age, fracture side, fracture type, basic social data, activities before injury, injury causes and treatment were analyzed.</p><p><b>RESULTS</b>A total of 219 patients (106 male and 113 female) was analyzed. All patients were divided into children group (age < 16 years), adult group (age ranged from 16 to 60 years) and older group (> 60 years). There were 5 patients (2.3%) in the children group, 81 patients (37.0%) in the adult group and 133 patients (60.7%) in the older group. There were 11 patients (5.0%) with Garden I fractures, 32 patients (14.6%) with Garden II fractures, 90 patients (41.1%) with Garden III fractures and 86 patients (39.3%) with Garden IV fractures. Fall damage and traffic injury were the main injury types. Home and public place were the main injury sites.</p><p><b>CONCLUSIONS</b>The incidence of femoral neck fracture shows the highest in the old persons. The male patients with femoral neck fractures are more than female patients in children and adult group, while the male patients with femoral neck fractures are less than female patients in older group. The dominant fractures type according to Garden classification is Garden III fractures in children and adult groups, but Garden IV fractures in older group. Fall damage and traffic injury are the main injury types. Home and public place are the main injury sites.</p>

Clinical outcomes of total elbow replacement in the treatment of complex distal humeral fractures / 中华外科杂志

<p><b>OBJECTIVE</b>To discuss the efficacy of total elbow replacement in the treatment of complex distal humeral fractures.</p><p><b>METHODS</b>From May 2005 to October 2008 12 patients were retrospectively studied who were diagnosed complex fractures of the distal humerus and treated by total elbow replacement (Coonrad-Marrey). The mean age was 60 years old, the mean follow-up time was 12 months. According to AO classification, there was 3 C2 and 9 C3. The study included: pain evaluation, range of motion, elbow stability, muscle strength, complications, Mayo elbow score, DASH score, radiological assessment of ectopic bone formation and loosening.</p><p><b>RESULTS</b>Two cases with mild pain. The mean flexion is 98.3 degrees, extension limit is 17.9 degrees, mean pronation is 82.9 degrees and supination is 70.8 degrees. All joints were stable postoperatively. All patients were satisfied with the outcome. There was 1 case of superficial soft tissue nonhealing and 2 cases of ulnar nerve symptoms. No ectopic bone formation or loosening was found. Mayo elbow score was 3 cases of excellent and 9 cases of good. The mean DASH score was 41.3.</p><p><b>CONCLUSION</b>Total elbow replacement can be used in such conditions as severe osteoporosis, severe comminution that internal plates can not get stable fixation, severe cartilage damage (because of fracture or inflammatory arthritis) that indicate traumatic or inflammatory arthritis.</p>

Gene transfer system mediated by PEI-cholesterol lipopolymer with lipid microbubbles / 药学学报

The properties of polyethyleneimine-cholesterol cationic lipopolymer (PEI-Chol) as gene carries and its gene transfer efficiency in vitro with lipid microbubbles were presented in this paper. PEI-Chol lipopolymer was synthesized by linking cholesterol chloroformate to the amino groups of branched poly(ethyleneimine) (PEI) of 1 800. The structure and molecular weight of PEI-Chol were confirmed by IR, 1H NMR and MADI-TOF-MS (matrix-assisted laser desorption/ionization time-of-flight tandem mass spectrometry), respectively. The average molecular weight of PEI-Chol was approximately 2 000. The gene delivery system of bubble/PEI-Chol/DNA was constructed by mixed PEI-Chol/pDNA (N/P 10:1) complexes with lipid microbubbles (2-8 microm) which were prepared by DPPC, DSPE-PEG2000 and perfluoropropane with the reverse phase evaporation technique. pEGFP-Cl (enhanced green fluorescent protein) was used as report gene to investigate the DNA condensing ability of PEI-Chol lipopolymer by agarose gel electrophoresis. And their cytotoxicity and in vitro transfer efficiency of different complexes were compared with each other in A549 and MCF-7. The results indicated PEI-Chol lipopolymer can condense plasmid DNA when N/P ratio upto 4, PEI-Chol complexes and bubble/PEI-Chol/DNA complexes were nontoxic to A549 and MCF-7 when formulated at the N/P ratio of 10/1 as determined by MTT assay. This bubble/PEI-Chol/DNA delivery system provided good transfer efficiency with other desirable characteristics such as against-precipitation of plasma proteins. In conclusion, bubble/PEI-Chol/DNA complex is a novel non-viral gene delivery system.

Synthesis of polyrotaxane-camptothecin conjugates and evaluation of its anti-tumor effect / 药学学报

To prepare polyrotaxane-camptothecin conjugates and evaluate its anti-tumor effect, polyrotaxane-camptothecin conjugates were successfully synthesized, and the release behavior was performed; MTT assay and cell morphology were used to examine the inhibition of cells' proliferation effect in vitro. The experimental study of the antitumor effect on S180 mice in vivo was also performed to further evaluate the anti-tumor effect of conjugate. The result showed polyrotaxane-camptothecin conjugates can effectively inhibit the proliferation in a dose dependent effect. In vivo study and cell morphology observation of S180 mice showed significant decrease in growth of tumor, degree of tumor infiltration and blood vessel number. The result indicated anti-tumor mechanism may be through affect the angiogenesis and reduced blood supply to tumor cells and then leading to necrosis.

Preparation of the oral self-microemulsifying drug delivery system of GBE50 / 药学学报

To prepare the oral self-microemulsifying drug delivery system (SMEDDS) of GBE50, balance solubility method was used to screen emulsifier and assistant emulsifier; a pseudo-tamary phase diagram was used to prepare microemulsion; and orthogonal design was used to optimize formulation. Self-microemulsifying efficiency, dissolution, stability and pharmacokinetics of the preparation were studied. As a result, GBE50-SMEDDS of IPM, Cremophor EL, 1,2-propanediol and GBE50 could be self emulsified to form stable microemulsion with particle diameter between 20 and 50 nm when emulsifying with water. Its self-microemulsifying efficiency and dissolution are quick with good stability and it has a higher bioavailability than market existing agents Xingling particles. GBE50-SMEDDS is stable and effective.

The analysis of prognostic relative factors in patients with type-C fractures of distal radius after internal fixation / 中华外科杂志

<p><b>OBJECTIVE</b>To explore the clinical relative factors on the therapeutic effect of wrist joint function in patients with type-C fractures of distal radius treated with internal fixation.</p><p><b>METHODS</b>Retrospectively collect consecutive patients of type-C fractures of distal radius treated surgically with open reduction and internal fixation admitted from January 2001 to October 2007. Making Gartland and Werley Score of wrist joint function as the primary outcome variable, the following were assessed: the postoperative efficacy at the follow-up, and use non-conditional Logistic regression to analysis the correlation of wrist joint function with patients' age, gender, time from injury to operation, classifications of type-C fracture, methods of internal fixation and other clinical factors.</p><p><b>RESULTS</b>In this study, 56 patients met the inclusion were collected. The follow-up time was 3.1 to 29.2 months (mean follow-up 6.3 months). The result of Gartland and Werley Score: 24 patients were excellent, good 26, fair 3, and poor 3; the excellent and good rate was 89.29%. Monovariant and multivariant Logistic regression analysis demonstrated that postoperative efficacy was significantly associated with elder age, time from injury to operation, methods of internal fixation:age (OR = 4.64; 95%CI: 1.48 - 14.54; P = 0.009), time from injury to operation (OR = 9.00; 95%CI: 1.72 - 46.99; P = 0.009), methods of internal fixation (OR = 3.33; 95%CI: 1.10 - 10.12; P = 0.034).</p><p><b>CONCLUSIONS</b>Elder age (>or= 65 years) and delay of surgery (>or= 13 d) are the influential factors of postoperative functional outcome of distal radius fractures. For the treatment of intra-articular type-C fractures of distal radius, locking compression plate is more effective than T-type plate.</p>

Comparative study of distal radial fractures in the elderly treated with locking and non-locking plates / 中华外科杂志

<p><b>OBJECTIVE</b>To evaluate the clinical difference of locking and non-locking plates in the treatment of distal radial fractures in the elderly.</p><p><b>METHODS</b>Forty-nine patients with an average age of 68 years were included. The mean follow-up was 30 months. Five cases were traffic related injury, and others were simple falls. Fractures were classified according to AO classification system: 9 cases of A3, 4 cases of B, 11 cases of C1, 18 cases of C2, 7 cases of C3. Patients were grouped as locking group (29 cases) and non-locking group (20 cases).</p><p><b>RESULTS</b>Significant difference was not found between the two groups in active range of motion, Gartland and Werley score, radiological measurements and score.</p><p><b>CONCLUSION</b>Locking and non-locking plates have the same clinical outcome in the treatment of distal radial fractures in the elderly.</p>

Optimized preparation of ginkgolides A and B long-circulating solid lipid nanoparticles by central composite design and response surface method / 南方医科大学学报

<p><b>OBJECTIVE</b>To optimize the formulation of long-circulating solid lipid nanoparticles (LSLN) carrying ginkgolides A and B (GAB) extracted from traditional Chinese medicinal herbs.</p><p><b>METHODS</b>GAB-LSLN was prepared by high pressure homogenization. The effects of such factors as the contents of glycerol monostearate, soybean lecithin and Myrj 59 on the mean diameter, entrapment efficiency and drug loading were investigated using central composite design and response surface method. The data were analyzed using multi-linear equation and second-order polynomial equation for selecting the optimal conditions for LSLN preparation.</p><p><b>RESULTS</b>The method of second-order polynomial equation was superior to multi-linear equation method in view of the multiple correlation coefficients. Under the optimal conditions, the mean diameter, entrapment efficiency, and drug loading of the GAB-LSLN were 169.5 nm, 92.3% and 5.1%, respectively.</p><p><b>CONCLUSION</b>The optimized process for GAB-LSLN preparation is stable, feasible and allows high inclusion rate in the large-scale production of GAB-LSLN.</p>

Dextran-spermine polycation as a vector for gene transfection in vitro / 药学学报

This work reports the properties of dextran-spermine polycation (DSP) as a gene vector and its gene transfection efficiency in vitro. Oxidized dextran was reacted by reductive amination with spermine to obtain DSP, the resulted polycation was then incubated with plasmid pEGFP to form polyplexes by electrostatic interactions. DSP formed stable polyplexes when the weight ratio (DSP/DNA) varied from 4 : 1 to 20 : 1. The particle size and zeta potential of polyplexes were in the range of 162.6 - 187.9 nm and increased from + 8.45 mV to + 39.6 mV, respectively. DSP could effectively protect condensed DNA from DNase I degradation, and it showed strong buffering capacity in a certain pH range. The highest yields of transfection efficiency were found to be as high as Lipofectamine 2000 when the polyplexes were transfected to SMMC-7721 and BHK-21 cells at the weight ratio of 8 : 1. This research indicates that dextran-spermine polycation is a highly active gene vector in vitro.

An experimental study on biomechanical effects due to unilateral cortical bone defect in long tubular bone / 中华外科杂志

<p><b>OBJECTIVE</b>To investigate the biomechanics effect due to unilateral cortical bone defect of different size in long tubular bone.</p><p><b>METHODS</b>Seventy-six pieces of Sanhuang cock tibial were randomly divided into 7 groups. The unilateral diaphyses cortical were drilled holes of different size, include 1.5, 2.0, 2.5, 3.0, 3.5, and 4.5 mm, performed three-points bend single experiment. The intact bone cortical group was control group.</p><p><b>RESULTS</b>When there were bone structure destructions, the maximum of the bend load between 3 groups which bone defect diameter were 1.5 mm, 2.0 mm, and control was not significant difference (P = 0.824, 0.865), but the maximum of the bend load between 3 groups which bone defect diameter were 2.5, 3.0, and 3.5 mm decreasing about 14 percent of the control group (P = 0.015, 0.010, 0.021). and the maximum of the bend load which bone defect diameter were 4.5 mm decrease about 23 percent of the control group (P = 0.001).</p><p><b>CONCLUSIONS</b>If the diameter of bone cortical defect is within 22.63 +/- 1.39 percent of bone cortical outer diameter, there was no reduction of the bend load. If the diameter of bone cortical defect is beyond 29.36 +/- 2.07 percent of bone cortical outer diameter, it decreases the maximum bend load of the long tubular bone, but the reduced range is not complete with direct ratio to the bone defect size.</p>

Biomechanical study of flexor tendon repair in an in vivo curvature model / 中华外科杂志

<p><b>OBJECTIVE</b>To compare the biomechanical characteristics of 2 different repair methods:Modified Kessler and Tsuge.</p><p><b>METHODS</b>Eighty-four profound flexor tendons of 3(rd) toe of Sanhuang chicken were severed and repaired by either Modified Kessler or Tsuge method randomly. Six repaired tendons for each repair method were harvested at 0, 1, 4, 7, 10, 14, 21 days after operation and tested in an Instron 1185 biomechanical testing machine. An elongation force-elongation distance curve was obtained, and biomechanical meters (including rupture force and rupture work) were calculated from this curve.</p><p><b>RESULTS</b>Rupture force: rupture force significantly decreased at 10(th) and 14(th) day in both repair groups, and returned to immediate level at 21(st) day in Modified Kessler group but not in Tsuge group; Tsuge method was significantly higher than Modified Kessler group at time-points immediately and 7 days after operation. Rupture work: this work significantly decreased at 10(th) (65.17 mJ) and 14(th) (40.0 mJ) day and resumed to immediate level at 21(st) day in Modified Kessler group; While in Tsuge group, it decreased significantly at 14(th) and 21(st) day. Tsuge method was significantly higher than Modified Kessler group only at time 0.</p><p><b>CONCLUSION</b>The biomechanical properties decrease significantly after 10(th) day at both repair method groups. It resumes to immediate level at 21(st) day in Modified Kessler group. There is no significant difference after 10(th) day between both repair methods.</p>

Characteristics of work of adhesion release in the early period of flexor tendon healing / 中华外科杂志

<p><b>OBJECTIVE</b>To investigate the characteristics of work needed to release adhesion in the early stage of flexor tendon healing.</p><p><b>METHODS</b>Eighty-four profoundus flexor tendons of the 3rd toe of Sanhuang chicken were severed and repaired by either Modified Kessler technique or Tsuge technique randomly. At 0, 1, 4, 7, 10, 14, 21 d after the operation, 6 tendons from each repair technique group were harvested and tested by biomechanical test machine. An elongation force-elongation distance curve was obtained and work of adhesion release was calculated in this curve. Whether adhesion band had been released or not was confirmed by gross inspection immediately after the test.</p><p><b>RESULTS</b>Work of adhesion release: this work significantly increased at the 7th day in Modified Kessler group and at the 10th day in Tsuge group. Modified Kessler group was significantly higher than Tsuge group at the 7th day. At the 21st day after operation, adhesion could not be effectively released by full range excursion of flexor tendon profoundus.</p><p><b>CONCLUSION</b>Work of adhesion release begins to increase significantly since the 7th approximately 10th day postoperatively. At the 21st day after the operation, adhesion could not be fully released by full range of flexor tendon profoundus flexion.</p>

Studies on design, synthesis and biodegradation of carrier for colon-site specific, drug delivery system / 药学学报

<p><b>AIM</b>To design and synthesize a novel vector for colon-site specific drug delivery system and investigate the relationship between the biodegradation properties and composition of materials in the simulated colon fluid.</p><p><b>METHODS</b>The azocopolymer P (HEMA-MMA-MAA) was synthesized using 2-hydroxyethylmethacrylate (HEMA), methyl methacrylate (MMA) and methacrylic acid (MAA) as comonmer, azobisisobutyronitrilel (AIBN) as initiator, cross-linked with divinylazobezene (DVAB). The chemical structure of the synthesized series of azocopolymer is examined by UV, FTIR spectroscopy and nuclear magnetic resonance data. Their swelling behavior is evaluated by the swelling equilibrium parameter Q, the biodegradation tests of the materials were carried out at physiologically relevant buffer designed to mimic the colon environment. The biodegradation properties were assessed using the differential scanning calorimeters (DSC) and gel permeation chromatography (GPC) and the morphology on the surface of materials before and after degradation was observed by scanning electron microscopy (SEM).</p><p><b>RESULTS</b>The swelling equilibrium parameter Q increased with increasing the contents of HEMA and MAA in the materials. The degradation behavior was relevant to the ratio of three components in the copolymers.</p><p><b>CONCLUSION</b>This materials may become a good carrier for the colon-site specific drug delivery system if the contents of commoners HEMA, MMA and MAA are adjusted reasonably.</p>