Xun-Zi Cai

Zhejiang University, Hang-hsien, Zhejiang Sheng, China

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Publications (16)34.2 Total impact

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    ABSTRACT: Previous research has found that low-intensity ultrasound enhanced the lethal effect of gentamicin on planktonic E. coli. We aimed to further investigate whether microbubble-mediated low-intensity ultrasound could further enhance the antimicrobial efficacy of gentamicin. The planktonic E. coli (ATCC 25922) was distributed to four different interventions: control (GCON), microbubble only (GMB), ultrasound only (GUS), and microbubble-mediated ultrasound (GMUS). Ultrasound was applied with 100 mW/cm(2) (average intensity) and 46.5 KHz, which presented no bactericidal activity. After 12 h, plate counting was used to estimate the number of bacteria, and bacterial micromorphology was observed with transmission electron microscope. The results showed that the viable counts of E. coli in GMUS were decreased by 1.01 to 1.42 log10 CFU/mL compared with GUS (P < 0.01). The minimal inhibitory concentration (MIC) of gentamicin against E. coli was 1 μ g/mL in the GMUS and GUS groups, lower than that in the GCON and GMB groups (2 μ g/mL). Transmission electron microscopy (TEM) images exhibited more destruction and higher thickness of bacterial cell membranes in the GMUS than those in other groups. The reason might be the increased permeability of cell membranes for gentamicin caused by acoustic cavitation.
    BioMed Research International 01/2014; 2014:142168. · 2.88 Impact Factor
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    ABSTRACT: Purpose. The aim of this study was to directly compare the efficacy and the safety of the two agents for postmenopausal women. Methods/Principal Findings. Electronic databases were searched for relevant articles that met our predefined inclusion criteria. Seven randomized controlled trials (RCTs) involving 4054 women were identified and included. Although Aln was more effective than Rlx in increasing bone mineral density (BMD), no statistical differences were observed in reducing the risk of neither vertebral fractures (P = 0.45) nor nonvertebral fractures (P = 0.87) up to two-year followup. Aln reduced the risk of vasomotor (P = 0.006) but increased the risk of diarrhea compared to Rlx (P = 0.01). Our subgroup analysis further indicated the difference between Aln and Rlx in fracture risk and was not materially altered by the administration pattern, the age. The weekly strategy of Aln would further reduce the upper gastrointestinal (GI) disorders and might gain more bone mass increment at lumbar spine compared to its daily treatment. Conclusion. There was no evidence of difference of fracture risk reduction between Aln and Rlx. In addition, age did not obviously influence their relative antifracture efficacy. For Aln the weekly strategy would further reduce the upper GI disorders and gain more bone mass increment compared to the daily treatment. During clinical decision making, the patients' adherence and the related side-effects associated with both drugs should also be taken into account.
    International Journal of Endocrinology 01/2014; 2014:796510. · 2.52 Impact Factor
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    ABSTRACT: With development in the techniques of reduction and fixation, there has been a controversy in comparison between intramedullary nailing (IMN) and plating for the treatment of distal tibial metaphyseal fracture (DTF). The study aimed to investigate: (1) which fixation, IMN or plating, was better in the clinical outcomes and in the complications for the treatment of DTF and (2) which modifying variables affected the comparative results between the two modalities. PubMed, EMBASE, OVID, Scopus, ISI Web of Science, the Cochrane Library, Google Scholar and specific orthopaedic journals were searched from inception to July 2013, using the search strategy of '('Fracture Fixation, Intramedullary' [MeSH]) AND ('Tibial Fractures' [MeSH]) AND (plate OR plating)'. All prospective and retrospective controlled trials comparing function, pain, bone union and complications between IMN and plating for DTF were identified. Our analysis had no limitation of the language or the publication year. The primary outcome measurements were complication rate, union time, operation time and hospital stays, while the secondary outcome measurements were functional score and pain score. Fourteen of 6620 studies with 842 patients were included. IMN was probably preferential to plating for DTF given its higher functional score (p=0.01), lower risk of infection (p=0.02) and comparable pain score (p=0.33), total complication rate (p=0.53) and time to union (p=0.86). However, plating had a lower malunion rate than IMN (p<0.0001). All the results were based on the Grading of Recommendations Assessment, Development and Evaluation (GRADE) evidence of moderate quality. With a satisfying alignment obtained, IMN may be preferential to plating for fixation of DTF with better function and lower risk of infection. However, IMN showed higher malunion rate for fixation of DTF. With the biases in our meta-analysis, it will ultimately require a rigorous and adequately powered randomised controlled trial (RCT) to prove. Level III, therapeutic study (systematic review).
    Injury 10/2013; · 1.93 Impact Factor
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    ABSTRACT: Osteoporotic vertebral compressed fractures (VCFs) are the most common osteoporotic fractures. Although percutaneous vertebroplasty (PVP) reportedly relieves pain and improves function, a recent pooled analysis from two multicenter randomized controlled trials concluded the improvement in pain and disability treated with PVP was similar to those with sham surgery. Using meta-analysis we therefore asked whether compared with either nonoperative therapy or a sham injection for patients with VCF, PVP would (1) better relieve pain, (2) provide greater improvement in pain-related disability, and (3) increase the recurrence of vertebral fractures. We searched PubMed, EMBASE, Medline, and the Cochrane library using the keywords "vertebroplasty AND osteoporosis OR fracture". We included nine of the 469 articles identified. Using a random effects model, we calculated the weighted mean differences to evaluate the pain reduction at different times as the primary outcome. Pain-related disability was assessed by a quality of life (QOL) measure. Improvement of QOL and recurrence of vertebral fractures were the secondary outcomes. We used subgroup analysis to reinvestigate pain relief and function improvement of PVP based on two different controls: nonoperative therapy and sham injection. The total number of patients was 886. Pain scoring was similar between the PVP group and the sham injection group at 1 to 29 days and 90 days. However, compared with nonoperative therapy, PVP reduced pain at all times studied. QOL in the PVP group was improved or tended to be improved compared with QOL for both control groups. The risk of new fractures was similar between the PVP groups and both control groups. Different control groups may have accounted for the different conclusions in the literature regarding the ability of PVP to relieve pain and restore function recovery. Compared with nonoperative treatment PVP relieved pain better and improved QOL. PVP did not increase the risk of new fractures. Level II, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.
    Clinical Orthopaedics and Related Research 06/2012; 470(10):2785-99. · 2.79 Impact Factor
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    ABSTRACT: We investigated the effect of local low-intensity pulsed ultrasound (LIPUS) on polyethylene debris induced periprosthetic osteolysis. The periprosthetic osteolysis model was made by injecting endotoxin-free pure polyethylene particles into the distal part of the femur canal and inserting a stainless steel plug into this femur. The effects of polyethylene and LIPUS were assessed histologically and by the shear strength test and periprosthetic bone mineral density (BMD) test. Sixteen rabbits received a stainless steel plug on one side and both polyethylene and a stainless steel plug on the other side. Three months later, the side that received polyethylene showed periprosthetic osteolysis. Subsequently, another 16 rabbits received polyethylene plus local LIPUS (200 mW/cm(2) for 20 min daily) on one side and polyethylene alone on the other side. Three months later, LIPUS effectively prevented the periprosthetic osteolysis caused by polyethylene in this rabbit model.
    Ultrasound in medicine & biology 02/2012; 38(2):238-46. · 2.46 Impact Factor
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    ABSTRACT: It is well accepted that the minimally invasive surgery (MIS) for total hip arthroplasty (THA) should combine with less or no muscle damage and is different from mini-incision technique and MIS should have better outcomes than mini-incision surgery. The aim of current analysis was to apply an explicitly defined sub-group analysis to confirm whether this hypothesis is true. A computerized literature search was applied to find any data concerning MIS or mini-incision THAs. A multistage screening was then performed to identify randomized studies fulfilling the inclusive criteria for the analysis. The data were extracted, and sub-group analyses of MIS or mini-incision surgery for different kinds of outcomes were carried out. The P(sub) value for difference between MIS sub-group and mini-incision sub-group was also calculated. Eleven studies that fulfilling the inclusion criteria were included, with 472 cases in the study group (MIS or mini-incision) and 492 cases in the conventional group. The overall analysis showed the study group would achieve less surgical duration (P = 0.037), intraoperative blood (P < 0.001) and incision length (P < 0.001) than conventional group. The difference between sub-groups showed, the MIS would achieve shorter incision length (P(sub) < 0.05) and bigger cup abduction angle (P(sub) < 0.05), and cause more blood loss (P (sub) < 0.05) than mini-incision technique. Other indexes were comparable between the two sub-groups. Though further high quality studies are still needed, the result of current analysis offered an initial conclusion that MIS THA failed to achieve a better clinical outcome than mini-incision technique. The exact definition of MIS still needs to be improved.
    Chinese medical journal 12/2011; 124(24):4316-23. · 0.90 Impact Factor
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    ABSTRACT: This work was carried out to evaluate the clinical efficacy and the complications of S-ROM modular hip arthroplasty combined with transverse subtrochanteric shortening for Crowe type IV congenital dislocation of the hip (CDH). A total of 28 consecutive patients with Crowe type IV CDH received treatment using this surgical technique from June 2003 to June 2010. The follow-up was conducted at 3 days, 1, 6, and 12 months after the operation and later annually at the outpatient of our hospital. Sequential pelvic plain film and normotopia film of the affected hip joint were taken. The limp and the Trendelenburg sign were also assessed, the ischiadic nerve injury was also evaluated by electromyogram, and Harris hip scores were recorded. After operation, both the alignment and the position of the transverse osteotomies were good. None of the patients had presented complications of joint infection, prosthesis loosening, joint dislocation, or nerve injury. S-ROM modular hip arthroplasty combined with transverse subtrochanteric shortening was a satisfactory and safe technique for the Crowe type IV congenital hip dislocation within a mean follow up of 53 months. Transverse subtrochanteric shortening could effectively prevent the distraction injury of sciatic nerve.
    Chinese medical journal 12/2011; 124(23):3891-5. · 0.90 Impact Factor
  • Orthopedics 11/2011; 34(11):837-8; author reply 838. · 1.05 Impact Factor
  • Shi-Gui Yan, Le-Yi Huang, Xun-Zi Cai
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    ABSTRACT: The osteonecrosis of femoral head (ONFH) has been a common disorder in clinical orthopaedic practice. ONFH is the relative contraindication of hip arthroplasty for the young and active patients since they suffer a high rate of revision and inferior function postoperatively. The primary importance in therapy is to prevent the progression of the disease and the collapse of the articular surface in order to keep away from hip arthroplasty. Low-intensity pulsed ultrasound (LIPUS) has been indicated to enhance the osteogenic differentiation of mesenchymal stem cells, stimulate the differentiation and the proliferation of osteoblasts, inhibit osteoclasts, improve the local blood perfusion and the angiogenesis, and accelerate the healing process of the stress fracture. We present a hypothesis that LIPUS may be an appropriate non-invasive modality for bone repair in the early stage of ONFH so that the progressive collapse of the articular surface and the subsequent arthroplasty would be avoided.
    Medical Hypotheses 01/2011; 76(1):4-7. · 1.18 Impact Factor
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    ABSTRACT: We investigated the effects of locally and systemically administered alendronate on wear debris-induced osteolysis in vivo. Endotoxin-free titanium particles were injected into rabbit femurs, prior to insertion of a nonweight-bearing polymethylmethacrylate plug into the distal femur canal. Then the particles were repeatedly injected into the knee 2, 4, and 6 weeks after the implantation. Alendronate was incorporated at three different concentrations (0.1, 0.5, and 1.0 wt %) into bone cement for local delivery. For systemic delivery, alendronate was subcutaneously injected (1.0 mg/kg/week) 1 week after the implantation and then once a week until sacrifice. Eight weeks postoperatively, there was significant evidence of osteolysis surrounding the plug in the control group compared with markedly blocked osteolysis in the 0.5 wt % and the 1.0 wt % groups, and the systemic group. There was a concentration-dependent effect of alendronate-loaded bone cement on the improvement of peri-prosthetic bone stock. Notably, no significant differences were found between the 0.5 wt % and the systemic group in peri-prosthetic bone stock and implant fixation. Collectively, although the biological efficacy after the systemic delivery of alendronate was slightly higher than that in the local treatment groups, alendronate-loaded bone cement may be therapeutically effective in inhibiting titanium particle-induced osteolysis in vivo.
    Journal of Orthopaedic Research 07/2010; 28(7):893-9. · 2.88 Impact Factor
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    Xun-Zi Cai, Ai-Dong Jin, Shi-Gui Yan
    International Orthopaedics 07/2009; 34(3):453-4; author reply 455. · 2.32 Impact Factor
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    ABSTRACT: To investigate the biomechanical strength of diphosphonate impregnated bone cement (DIBC). DIBC specimens were manufactured and randomly assigned to the control groups and the DIBC groups. According to the corresponding ASTM/ISO standards, the static biomechanical strength and the fatigue limit were tested systematically. The particle size distribution of diphosphonate powder was analyzed with the laser light scattering method. The fatigue test results, given as number of cycles-to-failure, were analyzed using the linearized format of the two-parameter Weibull function. With the drug load increased, there was a slight increase in static biomechanical strength and a moderate decrease in fatigue limit, both with statistical significance. When immersed in PBS before the tests, the DIBC specimens presented an overall significant decrease of static biomechanical strength and fatigue limit. The profile of drug particle sizes presented a normal distribution. The adopted diphosphonate is a much homogeneous powder which contains particles with a low range of sizes. The impregnation of diphosphonate exerted no or less negative effect on the biomechanical strength of the acrylic bone cement, of which the static strength of DIBC is maintained high above the ASTM/ISO standards.
    Zhonghua wai ke za zhi [Chinese journal of surgery] 04/2009; 47(6):465-8.
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    Acta Orthopaedica 01/2009; 79(6):870; author reply 871-2. · 2.74 Impact Factor
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    ABSTRACT: Ultrasound holds promise for enhancing the vancomycin release from cement though the length of time when local drug level exceeded the minimum inhibitory concentration (T(>MIC)) was not prolonged by the previous protocol of milliwatt-level ultrasonication. Here vancomycin-loaded cements were subjected to continuous watt-level ultrasonication (CUG), intermittent watt-level ultrasonication (IUG) or no ultrasonication (NUG) for 14 d during immersion in 40-ml phosphate buffered saline (PBS) for 28 d. The T(>MIC) for IUG was more than three times that for NUG. In contrast, T(>MIC) for CUG was slightly shortened. The subtherapeutic release of vancomycin between 15 d and 28 d for IUG was one-ninth that for NUG. The fitting equations indicated a significant enhancement on the burst release and the slow release for IUG; however, the continuous ultrasonication hampered the slow release. SEM images exhibited denser craters and pores with larger diameters and less residual drug in specimens from IUG relative to those from both CUG and NUG. Intermittent watt-level ultrasonication improved the ultrasound-enhanced vancomycin release from cement in view of the prolonged T(>MIC) and the inhibited subtherapeutic release compared with continuous ultrasonication. The mechanisms may be associated with the distinctive effects of detaching forces and pushing forces by acoustic microstreams.
    Journal of Biomedical Materials Research Part B Applied Biomaterials 12/2008; 90(1):11-7. · 2.31 Impact Factor
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    Clinical Orthopaedics and Related Research 12/2008; 467(2):582-4. · 2.79 Impact Factor
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    ABSTRACT: This study sought to investigate the effect of delayed pulsed-wave ultrasound with low frequency on drug release from and the antimicrobial efficacy of vancomycin-loaded acrylic bone cement in vivo and the possible mechanism of this effect. After the implantation of cement and the inoculation of Staphylococcus aureus into the bilateral hips of rabbits, ultrasound (average intensity, 300 mW/cm(2); frequency, 46.5 kHz; on/off ratio, 20 min/10 min) was applied to animals in the normal ultrasound group (UG(0-12)) from 0 through 12 h after surgery and to those in the delayed-ultrasound group (UG(12-24)) from 12 through 24 h after surgery. The control group (CG) was not exposed to ultrasound. Based on vancomycin concentrations in left hip cavities at projected time intervals, the amount of time during which the local drug concentration exceeded the MIC (T(>MIC)) in UG(12-24) was significantly prolonged compared with that in either CG or UG(0-12), and the ratios between the areas under the concentration-time curves over 24 h and the MIC for UG(0-12) and UG(12-24) were both increased compared with that for CG. The greatest reductions in bacterial densities in both right hip aspirates and right femoral tissues at 48 h were achieved with UG(12-24). Local hemorrhage in rabbits of UG(0-12) during the 12-h insonation was more severe than that in rabbits of UG(12-24). Of four variables, the T(>MIC) and the bioacoustic effect were both identified as parameters predictive of the enhancement of the antimicrobial efficacy of cement by ultrasound. Sustained concentrations above the MIC replaced early high maximum concentrations and long-term subtherapeutic release of the drug, provided that ultrasound was not applied until local hemorrhage was relieved. The enhancement of the antimicrobial efficacy of cement by ultrasound may be attributed to the prolonged T(>MIC) and the bioacoustic effect caused by ultrasound.
    Antimicrobial Agents and Chemotherapy 10/2007; 51(9):3199-204. · 4.57 Impact Factor