Objective To compare the effect and coverage of bacteriostasis of chitosan and sodium hyaluronate. Methods Each of the five bacteria, Proteus mirabilis, Escherichia coli, Candida albicans, Pseudomonas aeruginosa, Staphylococcus aureus, was cultivated for 33 tubes of broth culture. Leaving three tubes each group as control group, ploidy diluted concentration of high relative molecular weight chitosan, low relative molecular weight chitosan and sodium hyaluronate were added respectively in the broth culture. All the tubes were cultivated for 18 hours at 37 ℃ with homeothermia. Then the growth of bacteria was observed. ResultsThe minimal inhibitory concentrations (MIC) of high relative molecular weight chitosan were : Proteus mirabilis 0.031%, Escherichia coli 0.063%, Candida albicans 0.063%, Pseudomonas aerugionosa 0.063%, Staphylococcus aureus 0.063%; and the MIC of low relative molecular weight chitosan were: Proteus mirabilis 0.125%, Escherichia coli 0.025%, Candida albicans 0.25%, Pseudomonas aeruginosa 0.25%, Staphylococcus aureus 0.125%; bacteria grew well in each tube of sodium hyaluronate group and control group. Conclusion The above results show that sodium hyaluronate has no bacteriostasis, while chitosan has bacteriostasison broad spectrum and high relative molecular weight chitosan has ber effect.
Objective To observe the main biological characteristics and chondrogenesis potency of bone marrow -derived stromal cells(MSCs) after cytokinesinduction or gene modification in vitro. Methods MSCs from an adult New Zealand white rabbit were isolated and cultivated, and then MSCs were divided into the common medium group(Group A, 15%FBS in DMEM), the induced group by cytokines (Group B), the transfected group(Group C)with adenovirus-hepatocyte growth factor transgene (adHGF). The medium of group B consisted of transforming growth factor-β1(TGF-β1,10 ng/ml), basic fibroblast growth factor(bFGF,25 ng/ml) addexamethasone (DEX,10-7mol/L) with 15%FBS in DMEM. Cartilage slices wereobtained from femoral condyles and patellar grove in the same rabbit. The minced cartilage was digested in Ⅱ collagenase (3 mg/ml) to obtain chondrocytes(Group D). The change of cell appearance, proliferation capacity, glycosaminoglycans(GAG), immunohistochemical staining for type Ⅰ, Ⅱ collagen were observed during the 5th passage MSCs and MSCs after induction or gene modification. Expression of mRNA for type Ⅰ and Ⅱ collagen was detected by RT-PCR. Results Primary MSCs proliferated as shortspindle shape, while the 5th MSCs showed longspindle shape. Positive stain of type Ⅰ collagen could be found in groups A, B and C, while positivestain of type Ⅱ collagen was shown in groups B and D. The content of GAG in group B was higher than that in group A, but there was no significant difference between them（Pgt;0.05）, and there was significant difference between groups A and D（Plt;0.05）. No significant difference was noted in groups A,B and C on proliferation by MTT（Pgt;0.05）,except that of at the fourth day after transfection between groups A and C（Plt;0.05）. RT-PCR demonstrated that MSCs always had higher levelsof mRNA type Ⅰ collagen in groups A, B and C. The expression of mRNA type Ⅱ collagen was identified in groups B and D, and only low levels of mRNA type Ⅱ collagen in group C. Conclusion The above results indicate MSCs have a natural tendency of osteogenic differentiation in vitro culture, and also demonstrate the chondrogenic potency with the technique of cytokines induction or gene modification after passage. MSCs can be transfected efficiently being seed cells in tissue engineered bone or cartilage to accept target genes such as adHGF, and have a higher levels of expression in vitro, which lasted 4 weeks at least.
Objective To compare the effect of small intestinal submucosa(SIS)and polypropylene mesh(PPM) on repairing abdominal wall defects in rats, and toprobe into the feasibility of using SIS to repair the abdominal wall defects. Methods 100 SD rats(50 males and 50 females)were randomly divided into 2 groups(n=50). Their weight ranged from 200 to 250 g.Full thickness abdominal wall defects (2 cm×2 cm) were created by surgery and were repaired with SIS and PPM respectively. At different postoperative time (1st, 2nd, 4th, 8th and 12th week), animals were sacrificed to make histological observation. The tensile strengthand the development of adhesions were measured and observed. Results 95 animals survived and were healthy after surgery. No inflammatory response and obvious immunoreaction were observed in both groups. One week after operation, the tensile strengthof abdominal wall in SIS group (204.30±5.13 mmHg) was lower than that in PPMgroup(240.0±10.0 mmHg) at 1st week(P＜0.05),and there were no difference at 4th, 8th, 12th week. Adhesions were more marked in PPM group thanthat in SIS group(P＜0.05). Conclusion Both SIS and PPM are histologically compatible when used in rats and can maintain sufficient tensile strength. SIS is superior to PPM in regards to tissue compatibility and adhesion formation.
Objective To compare advantage and disadvantage of internal fixation method for tibia intercondylar eminence fracture between absorbable screw and metallic screw. Methods From 1996 to 2002, 200 patients with fracture of tibia intercondylar eminence were divided into group A (with absorbable screw, n=120) andgroup B (with metallic screw, n=80). And the biological compatibility, biomechanics, bone union and complications were compared between two groups.Results There were no obvious differences in operating time and circumstance of recovery position between two groups. Group A was obviously better than group B in biological compatibility, biomechanics, bone union, joint function recovery. The average healing time of group A was three months, that of group B was three and half months. The good rates of joint function in two groups were 98.0% and 95.0% respectively. The occurrence rates of wound arthritis were 1.7% and 3.7%. There wassignificant difference between them(P＜0.01). Conclusion Absorbable screw is a more ideal material of internal fixation to treat tibia intercondylar eminence fracture.
Rolling enrollment is a common method for participant recruitment in medical practice. In the longitudinal data, where researchers are often interested in outcomes occurring after a certain period of treatment, the definition of causal effects differs from that in the cross-sectional data. It poses new challenges for the application of matching methods in the longitudinal studies. Longitudinal matching is an extension of matching methods in longitudinal studies involving static interventions such as rolling enrollment. Currently, longitudinal matching methods are widely applied in the comparative effectiveness research. This article elucidates the fundamental principles, applicable conditions, code implementation, and application instances of four longitudinal matching methods through theoretical discussions and empirical illustrations. It provides methodological references for estimating causal effects in longitudinal data analysis.
Objective To explore the effects of various kinds of internal fixations on unstable intertrochanteric femoral fractures. Methods From January 2000 to December 2004,88 cases of unstable intertrochanteric femoral fractures were treated. There were 52 males and 36 females (aged 19-86 years). Twenty-two cases were caused by fall from height, 36 by motor vehicle accident and 20 by fall and 10 by tumble. They were divided into 4 groups according to 4 kinds of internal fixations: dynamic hip screw(DHS,group A, n=42), anatomical proximal femur bone plate (group B, n=23), proximal femoral nail（PFN，group C, n=8）and dynamic condylar screw (DCS, group D, n=15). According to the modified Evan’s classification, fractures were all unstable type and were classified as follow types: group A (15 type Ⅲ, 8 type Ⅳ and 19 type Ⅴ); group B (12 type Ⅲ, 5 type Ⅳ and 6 type Ⅴ); group C (3 type Ⅲ,2 type Ⅳ and 3 type Ⅴ); and group D (10 type Ⅲ,3 type Ⅳ and 2 type Ⅴ). The data of operative time, intra-operative blood loss, intraoperative complications, fluoroscopy exposures, clinical healing time of fracture, post-operative restored function and postoperative complications were recorded and analyzed statistically using the SPSS 12.0 software package.Results All patients were followed up for 12-48 month (18 months on average). All patients achieved clinical healing. Coxa varus occurred in 3 cases of group A, in 1 case ofgroup C and in 3 cases of group D . The differences were of no statistical significance in operative time and postoperative complications between 4 groups (P＞0.05). The difference was of statistical significance in the blood loss between groups A,B and groups C,D (P＜0.05) but no statistical significance between group C and group D (P＞0.05). The difference was of statistical significance in the fluoroscopy exposures, clinical healing time of fracture and postoperative complications between group B and the other groups (P＜0.05). The difference was of statistical significance in the postoperative restored functions between group D and theother groups (P＜0.05). Conclusion The anatomical proximal femur bone plate is a useful device in the treatment of unstable intertrochanteric femoral fracture. The operative manipulation is simple and the hip functions recover well.
Objective To investigate and compare the effects of restoring and maintaining the cervical curvature and height of the fused segment by using three different anterior cervical plate systems. Methods From January 2002 to June 2004, 122 patients underwent anterior cervical decompression,autogenous iliac bone graft and plate fixation. Of the 122 patients (85 males, 37 females, aged 14-70), 37 underwent surgery involving the fixation with the Orion plate system, 39 with the Zephir plate system, and 46 with the Codman platesystem. The cervical curvature and height of the fused segment were measured onthe lateral X-ray films so as to compare the changes of the conditions preoperatively,1 week after surgery, and during the follow-up, and also to compare the difference among the three groups. Results The follow-up of the patients for 6-35 months (average 17.3 months) showed that all the patients developed the bone fusion 6 months after operation. There was a significant improvement in the cervical curvature and height of the fused segment before operation versus 1 week after operation（Plt;0.05）; however, there were no significant changes 1 week after operation versus during the followup in each group（Pgt;0.05）; there was no significant difference among the three groups（Pgt;0.05）. Conclusion The three plate systems can effectively reconstruct and maintain the cervical curvature and height of the fused segment, with a satisfactory effect in a short term.
Objective To investigate the clinical therapeutic effects of two types of vaginoplasty. Methods From January 1996 to March 2005, 63 patients wih the congenital absence of the vagina were treated by two types of vaginoplasty. Of the 63 patients, 37 underwent vaginoplasty using the amnion and 26 underwent an improved laparoscopic Vecchitti operation. The durations ofthe operation and hospitalization, as well as the blood loss were compared between the two types of vaginoplasty. The vaginal moulds were improved during the operations. Results According to the follow-up for 2 months to 4 years in the 35 patients. Compared with vaginoplasty using the amnion, vaginoplasty by an improved laparoscopic Vecchitti operation had advantages of significantly shorter surgical duration, shorter hospitalization, and less blood loss (Plt;0.05). After the operations, the artificial vagina of all the 63 patients could hold a speculum and the mucosa appeared so soft and smooth with normal lubrication. The married patients were satisfied with the intercourse. However, after vaginoplasty using the amnion, an infection of the amnion occurred in 3 patients, scar contracture in 2 patients, one of whom underwent scar incision 13 months after operation with a success; but the other refuse to accept another operation. But the improved laparoscopic Vecchitti operation achieved a success in the patients without any infectionor scar contracture, according to the 2 month-2.5 years follow-up. Conclusion The improved laparoscopic Vecchitti operation is a preferred procedure of constructing a vagina for the patients suffering from the congenital absence of the vagina.
Objective To investigate an effect of the Fixion expandable intramedullary nail on treatment of the closed fracture of the tibial shaft, and to compare the Fixion nail with the traditional locked intramendullary nail.Methods From September 1, 2005 to August 31, 2006, 79 patients (53 men, 26 women; aged 17-57 years, 37 years on average) with the closed fracture of the tibial shaft were treated with the Fixion expandable intramedullary nail, and the effect of the nail was evaluated. According to the AO classification, the patients were typed as Type 42A or Type 42B. And the patients were divided into the following two groups: the expandable intramedullary nail group (n=31) and the traditional locked intramedullary nail group (n=48). Of the 31 patents in the first group, 24 were of Type 42A and 7 were of Type 42B; of the 48 patients in the second group, 37 were of Type 42A and 11 were of Type 42B. All the patients were followed up after operation. Observation was made on the time of the bony callus development and the time of the clinical healing of the bone,and on whether there was the bone malunion, late healing, disunion or infection. The limb function was also evaluated.Results The follow-up of all the 79 patients for 4-15 months averaged 10.3 months revealed that in the expandable intramedullary nail group, the average operating time was 35 minutes (range, 20-60 minutes), with no requirement of blood transfusion. The X-ray examination showed that the bony callus developed as early as 4 weeks after operation. The clinical healing time of the bone was 3-8 months, averaged 5 months. All the patients in this group had the healing by first intention. Evaluatedby the Johner-Wruhs method, an excellent result was found in 28 patients, goodin 3 patients, and poor in none of the patients, with an excellent/good rate of100%. In the traditional locked intramedullary nail group, the average operating time was 75 minutes (range, 45-110 minutes), with no requirement of blood transfusion. The X-ray examination showed that the bony callus developed as early as 4.5 weeks after operation. The clinical healing time was 3-12 months, averaged 5.8 months. In this group, 46 patients had the healing by first intention and 2 patients had the healing by second intention. Evaluated by the JohnerWruhs method,an excellent result was found in 35 patients, good in 11 patients, and fair in 2 patients, with an excellent/good rate of 95.8%.Conclusion The expandable intramedullary nail treatment has advantages of less invasion, simpler manipulation, earlier weightbearing of the bone, quicker healing ofthe bone fracture, and fewer complications. This kind of treatment is worth popularizing in the medical practice if the indication is strictly controlled.
Objective To investigate the therapeutic effects of anterior approach set (AAS) versus posterior approach set (PAS) in treating multilevel cervical disc herniation of three or four segments. Methods Fifty-six cases of multilevel cervical disc herniation were retrospectively studied. Thirty-seven casesunderwent anterior approach, and discectomy, selectively partial corpectomy with bone grafting and plate fixing was performed (AAS group); 19 cases underwent posterior approach, and laminectomy with lateral cervical mass plate screw fixing was performed (PAS group).Results The followup periods were 6 months to 4 years and 5 months, averaging 2 years and 10 months in AAS group and 1 year and 5 months to 5 years and 1 month, averaging 3 years and 8 months in PAS group. JOA functional assessment and sagittal diameter of dural sac were not-statistically significant between two groups before operation (Pgt;0.05) andwere significantly larger in AAS group than in PAS group after operation (Plt;0.01). The improvement rate of AAS was significant higher than that of PAS (Plt;0.01). The number of complication in AAS were slight more than that in PAS.Conclusion AAS is obviously better than PAS in the therapeutic effects. The operation of anterior decompression with bone grafting and plate fixing is an indication of multilevel cervical disc herniation of three or four segments.