A rapid spectrophotometric assay for tetracycline in gingival crevicular fluid

AIM: The aim of this study was to investigate a rapid spectrophotometric assay for its potential to measure tetracycline levels in gingival crevicular fluid (GCF). MATERIALS AND METHODS: The technique involves complexation of tetracycline with molybdenum in order to shift the absorbance spectrum away from that region where interference with plasma proteins is a problem. The sensitivity of the assay and reproducibility of elution were examined together with an assessment of the effect of plasma proteins. The assay was also tested in a small pilot clinical project, measuring tetracycline levels in GCF following placement of a test gel formulation in 25 periodontal pockets in 5 patients. RESULTS: The in vitro results showed good sensitivity of the assay over the concentration range tested (0.5-200 microg tetracycline) and with little effect of plasma proteins. Elution from the paper strips was reproducible with a good linear correlation between direct and filter absorbed assays (r=0.9989, p<0.01). The pilot clinical study indicated a mean half-time of tetracycline in GCF of 28 min with confidence intervals of 21 to 34 min, although wide variation between the drug levels of individual periodontal pockets was seen. CONCLUSIONS: The results indicate good sensitivity for this assay to measure tetracycline hydrochloride in vivo. The potential for rapidly processing large numbers of samples contrasts with the assay time and limited sample throughput of other methods such as high pressure liquid chromatography (HPLC) and suggests that the technique may be a useful addition to current techniques for measuring tetracycline hydrochloride in vivo.     

Production of Rantes/CCL5 in human gingival fibroblasts challenged with tumor necrosis factor alpha

Chemokines are small-secreted proteins that stimulate the directional migration of leukocytes and thereby mediate the inflammatory process. The present study investigates the capacity of human gingival fibroblasts to produce the beta chemokine Rantes/CCL5. In situ hybridization, immunohistochemistry and ELISA were used to measure the induction of Rantes/CCL5 at the mRNA and protein levels, both in unstimulated gingival fibroblasts as well as in fibroblasts treated with the proinflammatory cytokines tumor necrosis factor (TNF)alpha or interleukin (IL)-1beta. TNFalpha in different concentrations (0.1-10 ng/ml) induced Rantes/CCL5 mRNA expression and protein production in 24-h cultures of human gingival fibroblasts. The expression of Rantes/CCL5-mRNA and protein production, induced by TNFalpha, was evident at 6 h and thereafter increased continuously during the study period (24 h). IL-1beta (3-300 pg/ml) also enhanced the production of Rantes/CCL5 in gingival fibroblasts. The amount of Rantes/CCL5 induced by IL-1beta (300 pg/ml), however, was less than that induced by TNFalpha (10 ng/ml). The study suggests that human gingival fibroblasts, by producing the chemokine Rantes/CCL5, participate in the regulation of the host response during the inflammatory process in the periodontal tissue.     

Effects of diameter, chemical impregnation and hydration on the tensile strength of gingival retraction cords

Gingival retraction cords are useful clinical aids but little information is available regarding desirable physical features that would preserve their integrity under tensile forces. The study aimed to establish under experimental conditions the extent to which tensile strength is affected by variation in cord diameter; impregnation with ferric sulphate (FS) or aluminium sulphate (AS); and cord hydration (wet/dry). Commercial cords and standard cotton cords were assayed in an Instron 1137 machine. Data were analysed using t-test, and one- and four-way ANOVA. Results indicated that tensile strength for 200 commercial cords was 1.4950 +/- 1.032 kg; and for 560 cotton cords was 1.2964 +/- 1.4560 kg. Cord hydration had no significant effect on tensile strength, whereas impregnation with AS or FS, a smaller diameter, and/or being a cotton cord decreased tensile strength (P < 0.001). Bivariate analyses showed that hydrated commercial cords had higher tensile strength than dry specimens; hydrated or dry cotton cords were not different. The FS-impregnated cotton cords had lower tensile strength than AS-impregnated or control cords, and the effect was greater at higher FS concentrations. This study is one of the first evaluations of the physical properties of cords, highlighting characteristics that may minimize the risk of tearing.     

Changes in gingival crevicular fluid matrix metalloproteinase-8 levels during periodontal treatment and maintenance

OBJECTIVES: The aim of this study was to investigate the effect of scaling and root planing (SRP) and the maintenance phase of treatment on the gingival crevicular fluid (GCF) matrix metalloproteinase-8 (MMP-8) levels. MATERIALS AND METHODS: Clinical measurements and GCF samples were taken from four sites in 20 adult periodontitis patients before and after SRP and during a 3-month maintenance phase of treatment. MMP-8 levels were measured from GCF samples by time-resolved immunofluorometric assay (IFMA) with monoclonal antibodies. RESULTS: SRP improved the clinical indices as would be predicted, 6.1 mm (SD = 1.4) at baseline compared with 4.3 mm (SD = 1.6) post-treatment (P < 0.001). Attachment level (AL) reduced but not significantly between these two visits 13.4 mm (SD = 2.4) compared with 12.8 mm (SD = 2.4) (P < 0.08) post therapy. GCF MMP-8 levels reduced after initial treatment from 33.8 micro g/30 s sample to 23.5 micro g/30 s, which just failed to reach statistical significance (P = 0.07). However, when MMP-8 levels were expressed as a concentration, the differences following initial therapy were significant (54.1 ng/ micro L at baseline compared with 34.2 ng/micro L post treatment; P < 0.005). The difference, however, between the baseline MMP-8 levels (33.8 ng/30 s) and the final visit (16 ng/30 s) following maintenance was markedly significant (P < 0.001) for both absolute amounts and on a concentration basis. CONCLUSION: In conclusion, clinical improvement following SRP was associated with significant reductions in MMP-8 levels. The GCF concentration of MMP-8 decreased after initial therapy but reduced even more dramatically (approximately 50%) following a 3-month period of maintenance (P < 0.001).     

Modulation of androgen metabolism by phenytoin,oestradiol and tamoxifen in human gingival fibroblasts

OBJECTIVES: The aim of this investigation is to study androgen metabolism in gingival fibroblasts in response to phenytoin, oestradiol and the antioestrogen tamoxifen, in order to establish the possible role of hormones in the aetiopathogenesis of phenytoin-induced gingival overgrowth. MATERIALS AND METHODS: Six cell lines of human gingival fibroblasts were established in monolayer culture in Eagle's minimum essential medium. Duplicate incubations were performed independently with radiolabelled testosterone and 4-androstenedione, respectively (14C-T/14C-4-A), with optimal concentrations of phenytoin, oestradiol and tamoxifen alone and in combination. At the end of a 24-h incubation period, the medium was solvent extracted for steroid metabolites, which were separated by thin layer chromatography and quantified using a radioisotope scanner. RESULTS: The substrates were metabolised mainly to the diols, 5alpha-dihydrotestosterone (DHT) and 4-androstenedione or testosterone, with the two substrates used. The trends were that phenytoin and oestradiol significantly elevated the yields of the androgens DHT, diols and 4-A/testosterone from both substrates while tamoxifen inhibited the stimulatory effects of oestradiol and phenytoin alone and in combination (n=6; p<0.01, one-way anova). CONCLUSION: Specific hormone-mediated activity in response to phenytoin could contribute to the pathogenesis of gingival overgrowth, which can be decreased by the anti oestrogen tamoxifen.     

五磨脐贴促进腹部手术患者胃肠功能的恢复及对血清血管活性肠肽和降钙素基因相关肽的影响

目的通过观察腹部手术治疗后患者肠麻痹恢复情况,评价五磨脐贴对腹部术后胃肠功能恢复的促进作用;观察腹部手术患者血清中血管活性肠肽和降钙素基因相关肽的变化及五磨脐贴对其影响,探讨五磨脐贴促进腹部手术患者胃肠功能恢复的机理。方法80例患者分为两组,治疗组采用五磨脐贴外敷神阙穴,对照组不使用任何促胃肠动力药,观察患者术后肠鸣音恢复时间及术后肛门排气时间,观察两组血管活性肠肽和降钙素基因相关肽的变化。结果术后肠鸣音恢复时间及术后肛门排气时间组间比较,五磨脐贴治疗组的时间明显短于空白对照组,差异有显著性意义(P<0.01)。治疗前,两组血管活性肠肽和降钙素基因相关肽含量无=明显差异(P>0.05);治疗后,治疗组血管活性肠肽和降钙素基因相关肽较对照组明显降低,差异有显著意义P<0.05);五磨脐贴治疗组治疗前血管活性肠肽和降钙素基因相关肽含量明显高于治疗后,差异有非常显著性意义(P<0.01)。结论五磨脐贴抑制腹部手术患者血管活性肠肽和降钙素基因相关肽的分泌,促进胃肠功能的恢复。     

Duane's retraction syndrome: its sensory features

Purpose: To investigate binocularity in Duane’s retraction syndrome (DRS) and to evaluate whether or not there is a relationship between the sensory and clinical features of the syndrome. Methods: Clinical and sensory findings of 29 patients with DRS were recorded. Binocularity was tested with the Bagolini glasses (BG), Worth four‐dot (W4D), TNO and the stereo‐fly plate of the Titmus test. Results: Twenty‐four (83%) patients showed fusion with the BG at near and 23 (79%) had fusion at distance. With the W4D, 23 (79%) patients had fusion at near and 19 (65%) had fusion at distance. Seven (24%) patients demonstrated normal stereoacuity, 15 (52%) had reduced stereoacuity and the remaining seven (24%) patients had no measurable stereoacuity. In patients without stereoacuity, amblyopia (p < 0.001), type 2 and 3 DRS (p = 0.031) and exotropia (p = 0.003) in primary position were more common than in those with reduced or with normal stereoacuity. Restriction of ocular ductions was also more severe in patients without stereoacuity than in those with reduced or normal stereoacuity (p = 0.019, p = 0.016). Patients with type 2 and 3 DRS were significantly more likely to have amblyopia (p = 0.037), large‐angle heterotropia (p = 0.005) in primary position, upshoot or downshoot (p = 0.010) than those with type 1 DRS. Conclusions: Although approximately 75% of DRS patients had fusion and measurable stereoacuity, only 25% demonstrated normal binocularity. This report provides new data on the relationship of sensory features to most of the clinical findings of this syndrome. Sensory features, as well as most clinical features of the syndrome, are better in patients with type 1 DRS.     

Localized alveolar bone necrosis following the use of an arsenical paste: a case report

AIM: To describe some toxic effects of arsenic trioxide in the mouth, to condemn its continued use, and present a case in which a tooth was preserved despite significant bony destruction. SUMMARY: A case is presented in which severe alveolar bone necrosis resulted from leak-age of an arsenical devitalization paste into the periodontium.The tooth was root canal treated before root amputation, and restored with a cuspal coverage restoration. The tooth was observed to be symptomless and functional at the one-year follow-up. KEY LEARNING POINTS: * Arsenic and its compounds have no place in contemporary endodontics. * Dentists should protect their patients by avoiding the use of arsenic-containing materials and refusing to use products whose constituents are not known. * Localized bone necrosis may not require tooth extraction. Depending on the severity of the case, the tooth may be preserved by a combination of endodontic, periodontal,prosthodontic and maintenance therapies.     

最低装量检查法改进的探讨

目的对原有最低装量检查法进行改进,使其更具有操作性,更符合一些特殊制剂的特殊要求。方法采用比重法、容量替代法、容量加和法,分别对溃疡糊、水晶膏、氧化锌搽剂进行最低装量检查。结果原先无法进行的最低装量检查有了可行的方法。结论改进后的方法可靠、操作性强。