BACKGROUND:Large bone defect caused by various reasons has been a difficult problem in clinical practice. To establish a standard experimental animal model of critical bone defects has vital significance for evaluating the efficacy of bone osteogenesis using various materials and techniques.
OBJECTIVE:To establish the rabbit model of parietal critical bone defects and to determine the diameter of the critical defects of parietal bone in limited time.
METHODS:10 New Zealand white rabbits were selected. The skul seam was treated as the boundary. Four ful-thickness round defects of bone in the parietal bone were made, with diameters of 4, 5, 6 and 7 mm, so as to establish rabbit models of parietal critical bone defects. Gross anatomical observation, X-ray and cone beam CT were used to determine the bone density in the new bone defect area. The healing of bone defects was evaluated by histological examination.
RESULTS AND CONCLUSION:After 12 weeks, the 4 mm group showed high bone healing capacity significantly, and part of the bone bridge had been connected completely. Quantitative analysis of bone mineral density revealed that gray value at defect site and trabecular bone area at the same magnification and the same vision in the 4 mm group were significantly higher than the other three groups (P<0.001). Only a smal amount of new bone in the periphery of bone defects appeared in the 5, 6 and 7 mm groups. The center of defect site was mainly fil ed by fibrous connective tissue. The results confirmed that this study successful y established rabbit models of parietal critical bone defects. During the 12 weeks of observation, bone defects with a diameter of ≥ 5 mm could not be self-healed, which was conformed to the criteria of critical defects of bone, and could be used as a reference value for critical parietal bone defects of a rabbit.

To produce specific antibodies against malachite green ( MG) , one special hapten was synthesized and characterized, and conjugated to carrier protein as immunogen. The immunogen showed excellent reactogenicity and immunogenicity. One specific monoclonal antibody (mAb, named MG-DA4-C7) with high sensitivity and specificity for MG in indirect competitive enzyme-linked immunoassay ( icELISA ) was screened. The isotype was IgG1 and the light chain was κ type. After optimization of ELISA conditions, the proposed icELISA showed a 50% inhibition value ( IC50 ) of 0. 96 μg/L, a linear range ( IC20-IC80 ) of 0. 1-8. 1 μg/L and a limit of detection ( LOD, IC10 ) of 0. 05 μg/L for determination of MG. The assay showed cross-reactivity of 18. 1%, 26. 5% with crystal violet and brilliant green, respectively, and negligible cross-reactivity with other metabolites of MG (<0 . 1%) . The average recoveries of MG from spiked fish samples were from 87. 3% to 107. 3%. Good correlation (R2=0. 999) was obtained between the results of icELISA and those of liquid chromatography-tandem mass spectrometry analysis. The proposed icELISA is suitable for the determination of MG in fish samples in a simple and sensitive manner.

Humans ; Nails ; Hydroxyurea/adverse effects* ; Alopecia/chemically induced*

Objective:To identify causative genes for autosomal recessive woolly hair (ARWH) in a family.Methods:Clinical data were collected from two patients and other family members in a Chinese pedigree of Han nationality with ARWH. Peripheral blood samples were obtained from the two patients, their unaffected parents and 100 unrelated healthy individuals, and DNA was extracted from the blood samples. A next-generation skin-targeted sequencing panel was used to detect gene mutations in the patients, and Sanger sequencing was performed to verify the sequencing results. The function of protein encoded by the mutant gene was predicted.Results:Two missense mutations c.530T>G (p.Leu177Arg) and c.736T>A (p.Cys246Ser) were both identified in the LIPH gene of the two patients, which were inherited from their father and mother respectively. Neither of the two mutations was identified in the 100 unrelated healthy controls. Interspecies sequence alignment showed that leucine at amino acid position 177 and cysteine at amino acid position 246 of the protein encoded by the LIPH gene were highly evolutionarily conserved. As SIFT and Polyphen-2 softwares showed, the mutations c.530T>G (p.Leu177Arg) and c.736T>A (p.Cys246Ser) were both predicted to be detrimental variations.Conclusion:Two missense mutations c.530T>G (p.Leu177Arg) and c.736T>A (p.Cys246Ser) in the LIPH gene may contribute to the clinical phenotype of the two patients with ARWH in this family.

The hapten of Flumequine(FLU) with four carbon atoms spacer arm(FLUABA) was synthesized and coupled to bovine serum albumin(BSA) as immunogen using activated ester method. Balb/c mice were immunized by the artificial immunogen and the splenocytes of immunized mice were fused with Sp2/0 cells to obtain the monoclonal antibody(McAbs). A hybridoma cell line(DB6-E7) secreting anti-flumequine McAbs was obtained by limited dilution method and screened by indirect enzyme-linked immunosorbent assay(ELISA) using heterogenous coating antigen. The results showed that the subtype of the McAb was IgG_1, and the affinity was 8.19×10~8 L/mol. The haptens of FLU, FLUABA and FLUACA, with different space arm, were separately linked to ovalbumin(OVA) for heterologous or homologous coating antigen. The results of indirect ELISA and indirect competitive ELISA(icELISA) indicated that the heterologous coating antigen could improve the sensitivity of ELISA significantly. By heterologous coating antigen(FLU-OVA), the icELISA showed an IC_(50) value of 26.33 μg/L, LOD of 4.0 μg/L, and the workable range of 8-114 μg/L (IC_(20)-IC_(80)). Cross-reactivity studies showed that the McAbs were quiet specific for FLU, no cross-reactivity(<0.1%) was detected between the obtained McAbs and the quinolones compounds or other structural similarity compounds. The developed icELISA for FLU can satisfy the detection criteria of flumequine in animal food-products.

BACKGROUND: Laryngeal cancer can cause hoarse voice, dyspnea, and dysphagia, for which common surgical approaches or biotherapy hardly results when nodal metastases are present. Identification of the factors associated with laryngeal cancer metastases is a crucial task in the study of the malignancy, as such a revelation may help establish molecular markers for accurate assessment of metastases and develop biological agents to restrain the invasion and metastases.OBJECTIVE:To study the association of MMP-2, MMP-9, CD44v6, PCNA,nm23, VEGF, p53, Cath-D and E-cadherin with the metastasis of laryngeal cancer so as to provide evidence for clinical treatment of laryngeal cancer.DESIGN: An experimental study ofclinical specimens.PARTICIPANTS: All specimens of primary laryngeal cancer were obtained from patients receiving surgical treatment in the Department of Otolaryngology,Fourth Affiliated Hospital of Harbin Medical University from February 2002 to November 2003. Immunohistochemical examination of the specimens was conducted in the Third Affiliated Hospital of Sun Yat-sen University.INTERVENTIONS: The expressions of MMP-2, MMP-9, CD44v6, PCNA,nm23, VEGF, p53, Cath-D and E-cadherin were examined immunohistochemically in the specimens from 70 patients of laryngeal cancer. Logistic stepwise regression model was used to analyze the influence of the 9 clinicopathologic factors on lymph node metastasis.MAIN OUTCOME MEASURES: The expressions of MMP-2, MMP-9,CD44v6, PCNA, nm23, VEGF, p53, Cath-D and E-cadherin in laryngeal cancer specimens.RESULTS: Using the established equation to estimate lymph node metastasis, the frequency of lymph node metastasis was highest in patients with positive MMP-9 expression(Wald = 10. 350 1, P ＜ 0.05) . Lower E-cadherin expression was accompanied by higher frequency of lymph node metastasis, and nm23 expression in patients with lymph node metastases was significantly decreased in comparison with patients without metastases (Wald=6.189 6 and 6. 863 2, P ＜0.05).CONCLUSION: The expressions of MMP-9, E-cadherin and nm23 are useful indicators for preoperative prediction of lymph node metastasis of laryngeal cancer and provide valuable information for prognostic evaluation of the interventions.

Objective To compare the osteogenesis effect of platelet-rich fibrin (PRF) and platelet-rich plasma (PRP) and investigate the methods of repairing bone defect with PRF.Methods Four defects measuring 7 mm in diameter were made in the parietal bone of 16 New Zealand white rabbits.The defects named A,B,C,and D and were filled with PRF,PRF-mixed Bio-Oss (BO),PRP-mixed BO,and PRP separately.Every four rabbits were sacrificed at postoperative 2,4,8,and 12 weeks and defects were examined grossly,radiographically,and histologically.Besides,bone mineral density and bone trabecular area were determined and expressed as gray-scale values.Results Newly regenerated bone appeared at all defect areas at postoperative 2 weeks.Thereafter,more bone formations were observed over time and area B demonstrated the best bone healing followed by area C,A,and D in succession.Bone trabecular area in areas A,B,C,and D was 10.95 ± 0.58,15.45 ± 0.79,10.22 ± 0.43,and 6.58 ± 0.64 at postoperative 2 weeks with significant differences in pair comparison (F =22.869,P ＜0.01),followed by some increase at postoperative 4 and 8 weeks.Whereas,bone trabecular area in areas A,B,C,and D increased largely at postoperative 12 weeks (35.09 ± 0.58,59.44 ± 0.60,50.75 ± 1.56,and 30.94 ± 1.19) and showed significant difference when compared in a pair (F =1 002.904,P ＜ O.01).Conclusion PRF is superior to PRP in promoting bone formation,but a much better effect of PRF/BO composite is observed in bone repair.

BACKGROUND:Breast cancer stem cells not only lead to theoccurrence of breast cancer, but also may cause breast cancer metastasis and recurrence. The relationship between stem cells and cell resistance is also gaining increasing attentions, and the focus on the stem cell treatment may result in unexpected results.OBJECTIVE:To explore the reversal effect of psoralen on glutathione-S-transferase π (GST-π) in human breast cancer MCF-7/ADR cells and its mechanism.METHODS:MCF-7/ADR cells were cultured and enriched in serum-free medium to obtain breast cancer stem cells.RT-PCR and western blot were used to detect the expression of GST-π at the levels of gene and protein in the MCF-7/ADR cells after treatment with 0, 4, 8, 12, 16 mg/L psoralen. To observe the activation of nuclear factor-κB,western blot was used. The expression of GST-π was detected by RT-PCR in 18 μmol/L SN50 group and 8 mg/L psoralen group. Cell counting kit-8 assay was used to detect the effect of doxorubicin on cell proliferation.RESULTS AND CONCLUSION:Compared with the control group, psoralen reduced the expression of GST-π at the mRNA and protein levels, and significantly inhibited the activation of nuclear factor-κB. It was suggested that psoralen could reverse the multidrug resistance of human breast cancer MCF-7/ADR stem cells by decreasing the expression level of GST-π. The mechanism may be achieved by inhibiting the nuclear factor-κB signal pathway.

Objective To explore the effect of psoralen on topoisomerase IIα(TopoIIα) expression of breast cancer stem cells.Methods CD44+CD24-/low breast cancer stem cells were sorted from MCF-7/ADR by magnetic-activated cell sorting(MACS).We observed the growth characteristics of these stem cells through optical microscope and detected the growth-inhibitory effects of psoralen on breast cancer stem cells by CCK-8 assay and IC50 of adriamycin and adriamycin combined with psoralen to calculate the reversal index.The mRNA and protein expressions of Topo IIα were detected using RT-PCR and Western blot, respectively.Results Under the optical microscope, breast cancer stem cells presented spheres.IC10 and IC20 of psoralen on breast cancer stem cells were (6.77±0.23)μg/mL and (10.36±0.21)μg/mL.IC50 of adriamycin and adriamycin combined with psoralen on breast cancer stem cells was (90.03±3.56)μg/mL and (21.47±0.82)μg/mL, the reversal index was 4.19.Psoralen significantly raised the expressions of Topo Ⅱα at mRNA and protein levels.Conclusion Psoralen reversed the resistance of adriamycin by increasing the gene and protein expressions of breast cancer stem cells Topo Ⅱα and the drug targets.