Adjunctive low-dose doxycycline therapy effect on clinical parameters and gingival crevicular fluid tissue plasminogen activator levels in chronic periodontitis

Objective and design: The present study examined effectiveness of low-dose doxycycline (LDD) in combination with nonsurgical therapy on gingival crevicular fluid (GCF) tissue plasminogen activator (t-PA) levels and clinical parameters in chronic periodontitis (CP) a over 12-month period. Methods: GCF samples were collected, probing depth (PD), clinical attachment level (CAL), gingival index (GI) and plaque index were recorded at baseline, 3, 6, 9 and 12 months. CP patients (n = 65) were randomized to LDD or placebo groups. LDD group received LDD (20 mg) b.i.d for 3-months plus and root planing (SRP), while placebo group was given placebo capsules b.i.d for 3-months plus SRP. GCF t-PA levels were determined by ELISA. Friedman, Wilcoxon and Mann-Whitney test was used for statistical analysis. Results: Significant improvement was observed in all clinical parameters in both groups over 12-month period (p < 0.01). LDD group had lower PD, CAL and GI scores than placebo group at 6, 9 and 12-months (p < 0.05). GCF t-PA levels reduced in both groups over 12-month period (p < 0.01). LDD group had lower GCF t-PA levels than placebo group at 6 and 9-months (p < 0.05). Conclusions: These results provide additional information about usefulness of LDD therapy as an adjunct to nonsurgical therapy in long-term management of periodontitis. Received 8 May 2006; returned for revision 13 June 2006; accepted by J. Di Battista 12 July 2006     

多西环素肠溶微粒胶囊与片剂的人体生物等效性

目的 :研究多西环素肠溶微粒胶囊和多西环素片的人体生物等效性与药动学。方法 :2 0名男性健康志愿者随机分 2组 ,按双周期交叉口服单剂量 2 0 0mg多西环素的 2种制剂 ,分别于服药前及服药后 0 5 ,1,1 5 ,2 ,2 5 ,3,4,6 ,8,12 ,2 4,48,72h取血样 ,以HPLC法测定血浆中多西环素浓度 ,计算 2种制剂相对生物利用度参数 ,并评价其生物等效性。结果 :口服受试制剂多西环素肠溶微粒胶囊和参比制剂多西环素片的药动学参数 :cmax分别为 (3 6 5± 0 81) μg·mL-1和 (3 6 5± 0 73) μg·mL-1,tmax分别为 (2 5± 0 3)h和 (2 2± 0 7)h ,T1/ 2 (消除半衰期 )分别为 (2 1 4 8± 3 2 0 )h和 (2 1 85± 3 11)h ,AUC0→ 72 分别为 (72 18±2 2 6 8) μg·h·mL-1和 (72 0 6± 2 1 0 8) μg·h·mL-1,AUC0→∞ 分别为 (81 4 4± 2 4 94) μg·h·mL-1和 (81 82± 2 3 19) μg·h·mL-1,多西环素肠溶微粒胶囊相对生物利用度为 (10 1 9± 2 5 2 ) %,对参数cmax,AUC0→ 72 先进行方差分析 ,再进行双单侧t检验 ,表明 2种制剂的参数生物等效 ,tmax经非参数检验表明无统计学差异。结论 :多西环素肠溶微胶囊和多西环素片具有生物等效性。     

可调控的胰岛素基因表达载体的构建及其体外表达研究

目的构建四环素调控的胰岛素基因表达载体 ,并研究其体外转移后的表达情况。方法通过基因重组技术构建胰岛素基因的四环素调控表达系统 ,用脂质体转移法导入成肌细胞 ,以不同浓度的强力霉素诱导 ,检测诱导后胰岛素原mRNA表达及胰岛素 /胰岛素原水平。结果RT PCR显示此基因能在真核细胞内表达。细胞培养液中胰岛素水平在加药 2 4h后开始增加 ,至第 7天仍在增加 ,撤药后迅速下降 ,至撤药后第 5天下降到基础水平。不同诱导药物浓度诱导的胰岛素产量明显不同 (P <0 .0 5 ) ,而细胞内和培养基中的胰岛素浓度无明显差异 (P >0 .0 5 )。结论单一四环素调控的胰岛素原表达系统能在真核细胞内表达 ,并呈现强力霉素浓度依赖性     

Experimental doxycycline overdose in rats causes cardiomyopathy

All reports of doxycycline‐induced cardiomyopathy to date have been limited to accidental oral poisoning in calves. Therefore, the current study investigated the cardiomyotoxic effect of experimental doxycycline overdose in rats as a toxicity model which could be monitored using histopathological and biochemical assays. A total of 38‐week‐old male Wistar rats were divided into three groups consisting of 10 each. The first group was an untreated control group (D₀), and the second group (D₅) received doxycycline hyclate 25 mg/kg intragastrically twice daily (8 AM and 8 PM), which is 5‐fold higher than the standard dose. The third group (D₁₀) received 50 mg/kg intragastrically twice daily (8 AM and 8 PM), which is 10‐fold higher than the standard dose. The dose continued for 10 consecutive days and revealed that the doxycycline toxicity was dose dependent. Mortality was recorded in the D₁₀ group only (30%). The D₅ rats exhibited minimal skeletal muscle injury and slight but significant increases in the skeletal muscle damage indicators creatine kinase (CK) and aspartate aminotransferase (AST) compared to controls. The cardiac muscle of the D₅ rats was histologically normal, and the D₅ rats also exhibited normal levels of troponin I (cTnI), an indicator of cardiac muscle damage. In contrast, the D₁₀ rats displayed cardiomyopathy, as well as significant increases in the muscle enzymes alanine aminotransferase (ALT), AST and CK and the cardiac damage indicator cTnI compared to control and D₅ groups. Pulmonary lesions were observed in the D₁₀ rats, primarily cardiac lesion‐related alveolar heart failure cells. Thus the present study is the first to demonstrate that oral doxycycline poisoning (10 times the therapeutic dose)‐induced cardiomyopathy is not limited to calves and could occur without any predisposing factors.     

Antibacterial substantivity of a new antibiotic‐based endodontic irrigation solution

The aim of this study was to evaluate the residual antibacterial activity of Tetraclean, MTAD and 5.25% sodium hypochlorite (NaOCl) in bovine root dentin in vitro. One hundred and ten dentin tubes prepared from bovine incisor teeth were infected in vitro for 14 days with Enterococcus faecalis. Thereafter, the specimens were divided into five groups as follows: Tetraclean; MTAD; 5.25% NaOCl; infected dentin tubes (positive control); and sterile dentin tubes (negative control). Dentin chips were collected using round burs into tryptic soy broth and after culturing, the number of colony‐forming units (CFU) was counted. The number of CFU in all experimental groups was minimum after treatment, and the results obtained were significantly different from each other at any time period (P < 0.05). The Tetraclean group showed the most effective antibacterial action at all five experimental periods (P < 0.05). MTAD group showed the least antibacterial activity after treatment. However, at days 7, 14, 21 and 28 MTAD showed more effective antibacterial action than NaOCl. In each group, the number of CFU increased significantly by time‐lapse (P < 0.05). In conclusion, the residual antibacterial activity of Tetraclean was significantly greater than MTAD and 5.25% NaOCl.     

多西环素对哮喘大鼠血管内皮生长因子、基质金属蛋白酶9的作用及血管重塑的影响

目的 观察多西环素对哮喘大鼠血管内皮生长因子(vascular endothelial growth factor,VEGF)、基质金属蛋白酶9(matrix metalloproteinases-9,MMP-9)表达的影响.探讨多西环素对哮喘气道重塑、血管重塑的作用.方法 33只雄性SD大鼠随机分为对照组、哮喘组、多西环素组各11只.将大鼠以1％戊巴比妥钠麻醉,取材.收集支气管肺泡灌洗液(bronchoalveolar lavage fluid,BLAF),计数细胞总数、中性粒细胞、淋巴细胞及嗜酸性粒细胞;部分肺组织行病理切片,HE染色;免疫组织化学法检测各组大鼠肺组织中VEGF和MMP-9的表达变化,并应用图像分析软件技术测量VEGF和MMP-9的相对表达强度;ELISA法检测血清中VEGF的含量;应用计算机图像分析技术测定气道壁厚度及血管密度.结果 哮喘组的细胞总数和嗜酸性粒细胞高于对照组,多西环素组明显低于哮喘组,但仍高于对照组(均P＜0.01);哮喘组大鼠肺组织和血清中MMP-9及VEGF的平均光密度值高于对照组,多西环素组明显低于哮喘组,但仍高于对照组(均P＜0.01);哮喘组大鼠血清中的VEGF含量高于对照组,多西环素组低于哮喘组,但仍高于对照组(均P＜0.01).哮喘组大鼠的气道壁厚度与血管密度均高于对照组,多西环素组则明显低于哮喘组,但仍高于对照组(均P＜0.01).结论 MMP-9、VEGF对哮喘血管重塑有重要作用,多西环素具有减轻气道炎症和气道重塑的作用.     

Characterization of the release profile of doxycycline by PLGA microspheres adjunct to non-surgical periodontal therapy

The aim of this pilot study was to assess the release of locally delivered doxycycline by poly (l-lactide-co-glycolide) (PLGA) microspheres in the periodontal pocket of patients with chronic periodontitis, treated by non-surgical periodontal therapy. Nineteen sites of non-adjacent teeth of four different patients were evaluated. Five milligram of PLGA microspheres loaded with 16 doxycycline hyclate (DOX) was administered per periodontal site. To quantify DOX released into the periodontal pocket, gingival crevicular fluid (GCF) was collected from the sites on days 2, 5, 7, 10, 15, and 20 after DOX application, and high-performance liquid chromatography was performed. Data were statistically assessed by ANOVA/Tukey test. At days 2, 5, and 7, the DOX concentration was stably sustained (23.33 ± 1.38, 23.4 ± 1.82, and 22.75 ± 1.33 μg/mL, respectively), with no significant differences over these assessment times (p > 0.05). At days 10 and 15, a tendency was observed toward a decrease in DOX concentration (21.74 ± 0.91 and 20.53 ± 4.88 μg/mL, respectively), but a significant decrease in GCF drug concentration (19.69 ± 4.70 μg/mL) was observed only on day 20. The DOX delivery system developed demonstrated a successful sustained release after local administration, as an adjunct to non-surgical periodontal therapy.     

Clinical Experience With the Use of Doxycycline and Ursodeoxycholic Acid for the Treatment of Transthyretin Cardiac Amyloidosis

Background

The tolerability and utility of combination doxycycline and ursodeoxycholic acid (ursodiol) amyloid fibril disruption therapy for transthyretin cardiac amyloidosis (ATTR CA) in clinical practice is poorly described.