Measurement of mucosal thickness in denture-bearing area of edentulous mandible / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>The thickness of the alveolar mucosa influences the probability of the occurrence of denture-induced irritations. Thick denture-supporting tissues offer relief from mucosal tenderness and ulcers; however, the uniformity of the thickness across the entire mandibular alveolar mucosa cannot be accurately determined in edentulous patients. This study aimed to assess the mucosal thickness of the denture-bearing area in the edentulous mandible.</p><p><b>METHODS</b>Twenty-seven edentulous patients underwent cone-beam computed tomography scanning, wherein the patients wore a record base to retract soft tissues away from the alveolar mucosa. The measured regions were the central incisor (IC), lateral incisor (IL), canine (Ca), first premolar (P1), second premolar (P2), first molar (M1), and second molar (M2) regions. The thickness was measured in the alveolar ridge crest (T), buccal (B1-B4), and lingual (L1-L4) alveolar ridge mucosa. The average thickness of the mucosa at buccal sides (B) and lingual sides (L) were also assessed.</p><p><b>RESULTS</b>The differences in the mucosal thickness between the left and right sides were not significant. In the Ca-M2 regions, T was the thickest, and L3 was the thinnest of all the measured points in the same regions. L was significantly less than B in posterior regions (P < 0.01). On the other hand, M2 at L4 was thinnest of all the measured regions from Ca to M2 (P < 0.01), and was thicker than IC, IL, P1, and P2 at B2.</p><p><b>CONCLUSIONS</b>Since the mucosal thickness of denture-bearing area in the edentulous mandible is not uniform; the tissue surface of the denture base or custom tray should be selectively relieved, which may reduce the risk of denture-induced irritations.</p>

Case-control studies on complex tibial plateau and posterior condylar fractures treated through combined anterior-posterior (small incision or micro-incision) approach / 中国骨伤

<p><b>OBJECTIVE</b>To study the therapeutic effects of combined anterior-posterior (small incision or micro-incision) approach for complex tibial plateau and posterior condylar fractures.</p><p><b>METHODS</b>From 2000 to 2008, 79 patients (81 limbs) with complex tibial plateau and posterior condylar fractures were reviewed. There were 45 males and 34 females, ranging in age from 19 to 66 years, with an average of 40.6 years. Thirty-nine limbs were treated using small incision through combined anterior-posterior approach, in which 13 limbs were Schatzker type IV, 15 limbs were type V ,and 11 limbs were type VI. Other 42 limbs were treated using micro-incision through combined anterior-posterior approach, in which 18 limbs were Schatzker type IV, 16 limbs were type V, and 8 limbs were type VI. The Rasmussen scores for knee joint and radio scores were used to evaluate therapeutic effects after the treatment. The complications such as cutaneous necrosis and incision infection were observed.</p><p><b>RESULTS</b>All the patients were followed up. According to Rasmussen criterion, in small incision group, 16 limbs got an excellent result, 13 good, 7 fair and 3 bad; in micro-incision group,above data were 19, 11, 8 and 4 respectively. Comparison between the two groups, P = 0.924. Comparison of complications such as cutaneous necrosis and incision infection: in small incision group,10 limbs had the complications, and in micro-incision group were 4 limbs; the occurrence rate of small incision group were higher than that of micro-incision group (P = 0.047).</p><p><b>CONCLUSION</b>There are no significant differences between the two groups in the knee joint function rehabilitation; however, there is smaller rate for cutaneous necrosis and incision infection in micro-incision group.</p>

Study on anti-HBV effects of genetically engineered replication-defective hepatitis B virus expressing dominant negative mutants of core protein / 中华实验和临床病毒学杂志

<p><b>BACKGROUND</b>To explore the possibility of using HBV as a gene delivery vector, and to test the anti-HBV effects by intracellular expression of dominant negative mutants of core protein.</p><p><b>METHODS</b>Two kinds of full length mutant HBV genome, which express Core-partial P and Core-S fusion protein, were transfected into HepG 2.2.15 cell lines. Positive clones were selected and mixed in respective groups with hygromycin in the culture medium. HBsAg and HBeAg, which exist in the culture medium, were tested by ELISA and intracellular HBc related HBV DNA was examined by dot blot hybridization. The existence of recombinant HBV virion in the culture medium was examined by PCR.</p><p><b>RESULTS</b>The mean inhibitory rates of HBsAg were 2.74+/-3.83%, 40.08+/-2.05% (P less than 0.01) and 52.94+/-1.93% (P less than 0.01) in group 2.2.15-pMEP4, 2.2.15-CP and 2.2.15-CS, respectively. The mean inhibitory rates of HBeAg were 4.46+/-4.25%, 52.86+/-1.32% (P less than 0.01) and 41.60+/-1.65% (P less than 0.01), respectively. The inhibitory rates of HBc related HBV DNA were 15.3%, 82.0% and 67.2%, respectively. Recombinant HBV virion was detectable in the culture medium of only group 2.2.15-CP.</p><p><b>CONCLUSION</b>Dominant negative mutants of core protein can efficiently suppress wt-HBV replication and the expressions of HBV antigens. With the help of wild-type HBV, the recombinant HBV genome can form and secret HBV like particles, which provides evidence that the antiviral gene will be hepatotropic expression and the antiviral effects will be amplified.</p>

Development of hygromycin-resistant packaging cell line for hepatitis B virus-derived vectors / 中华实验和临床病毒学杂志

<p><b>OBJECTIVE</b>To cooperate with the study of HBV vector, hygromycin-resistant packaging cell line was developed that allows encapsidation of plasmids into HBV particles.</p><p><b>METHODS</b>Free of packaging signal, HBV genome was inserted into plasmid pMEP4, which expresses the HBV structural proteins including core, pol and preS/S proteins. HepG2 cell lines were employed to transfect with the construct. Hygromycin selection was done at a concentration of 150 micrograms/ml in the culture medium. The hygromycin-resistant clones with the best expressions of HBsAg and HBcAg were theoretically considered as packaging cell line and propagated under the same conditions. It was infected with recombinant retrovirus vector and hen selected with G418 and hygromycin in the culture medium. The existence of recombinant HBV virion in the culture medium was examined by PCR.</p><p><b>RESULTS</b>Hygromycin-resistant HBV packaging cell line was generated, which harbored an HBV mutant whose packaging signal had been deleted. Expressions of HBsAg and HBcAg were detectable. Infected with recombinant retrovirus pRV-CP, the hygromycin-resistant packaging cell line was found to secrete mutant HBV particles and no wild-type HBV was detectable in the culture medium.</p><p><b>CONCLUSION</b>After the packaging signal was deleted and transfected into HepG2 cell lines, the partial HBV genome lost its ability to form wild-type HBV, but conserves cis-action providing structural proteins for the packaging of the replication-defective HBV.</p>

Anti-HBV effects of genetically engineered replication-defective HBV with combined expression of antisense RNA and dominant negative mutants of core protein and construction of first-generation packaging cell line for HBV vector / 中华肝脏病杂志

<p><b>OBJECTIVE</b>To explore the possibility of using HBV as a gene delivery vector, and to test the anti-HBV effects by intracellular combined expression of antisense RNA and dominant negative mutants of core protein.</p><p><b>METHODS</b>Full length of mutant HBV genome, which expresses core-partial P fusion protein and/or antisense RNA, was transfected into HepG2.2.15 cell lines. Positive clones were selected and mixed in respective groups with hygromycin in the culture medium. HBsAg and HBeAg, which exist in the culture medium, were tested by ELISA method. Intracellular HBc related HBV DNA was examined by dot blot hybridization. The existence of recombinant HBV virion in the culture medium was examined by PCR. Free of packaging signal, HBV genome, which express the HBV structural proteins including core, pol and preS/S proteins, was inserted into pCI-neo vector. HepG2 cell lines were employed to transfect with the construct. G418 selection was done at the concentration of 400mug/ml in the culture medium. The G418-resistant clones with the best expression of HBsAg and HBcAg were theoretically considered as packaging cell lines and propagated under the same conditions. It was transfected with plasmid pMEP-CPAS and then selected with G418 and hygromycin in the culture medium. The existence of recombinant HBV virion in the culture medium was examined by PCR.</p><p><b>RESULTS</b>The mean inhibitory rates of HBsAg were 2.74% 3.83%, 40.08 2.05% (t=35.5, P<0.01), 66.54% 4.45% (t=42.3, P<0.01), and 73.68% 5.07% (t=51.9, P<0.01) in group 2.2.15-pMEP4, 2.2.15-CP, 2.2.15-SAS, and 2.2.15-CPAS, respectively. The mean inhibitory rates of HBeAg were 4.46% 4.25%, 52.86% 1.32% (t=36.2, P<0.01), 26.36% 1.69% (t=22.3, P<0.01), and 59.28% 2.10% (t=39.0, P<0.01), respectively. The inhibitory rates of HBc related HBV DNA were 0, 82.0%, 59.9%, and 96.6%, respectively. Recombinant HB virion was detectable in the culture medium of all the three treatment groups. G418-resistant HBV packaging cell line, which harbored an HBV mutant whose packaging signal had been deleted, was generated. Expression of HBsAg and HBcAg was detectable. Transfected with plasmid pMEP-CPAS, it was found to secrete recombinant HB virion and no wild-type HBV was detectable in the culture medium.</p><p><b>CONCLUSIONS</b>It has stronger anti-HBV effects by combined expression of antisense RNA and dominant negative mutants than by individual expression of them. With the help of wild-type HBV, the modified HBV genome can form and secret HBV like particles, which provides evidence that the antiviral gene will be hepatotropic expression and the antiviral effects will be amplified. The packaging cell line can provide packaging for replication-defective HBV, but with low efficiency.</p>