Biomedical subjects

T Blieden

Publications and source records attributed to T Blieden.

8 recordsLinked to original sources

PubMed2001

Adjunctive treatment with subantimicrobial doses of doxycycline: effects on gingival fluid collagenase activity and attachment loss in adult periodontitis.

OBJECTIVES: The therapeutic effects of doxycycline and other tetracyclines in the treatment of periodontitis involve, at least in part, mechanisms that are unrelated to their antimicrobial activity. Previous clinical studies have shown that doxycycline administered orally, at doses below those needed for antimicrobial efficacy, to human subjects with adult periodontitis resulted in significantly reduced collagenase activity in gingival crevicular fluid (GCF) and in extracts of inflamed gingival tissues. The purpose of the present study was to identify clinically effective dosing regimens using subantimicrobial dose doxycycline (SDD) as an adjunctive therapy in patients with adult periodontitis. MATERIAL AND METHODS: A total of 75 adult men and women qualified for enrollment into the three-part, placebo-controlled, double-blind, parallel-group study. Patients were stratified based on repeatedly exhibiting pathologic levels of periodontal attachment (ALv) and GCF collagenase activity at several appointments prior to baseline. Patients were administered a scaling and prophylaxis, then 1 of 5 treatment schedules for 12 weeks (part I), followed by a 12-week period of no drug therapy (part II), a second scaling and prophylaxis, and 12 additional weeks of treatment (part III). Primary determinants of efficacy included reductions in GCF collagenase activity and changes in relative ALv. RESULTS: 66 patients completed the 1st 12 weeks (part I) of the 3-part, 36-week study; 51 patients completed the entire 36-week study. From baseline to week 12 (part I), treatment with specially formulated SDD capsules (20 mg) 2x daily (1 x every 12 h) for up to 12 weeks was shown to significantly reduce GCF collagenase activity and to improve ALv, effects not seen in patients treated with placebo. Continuous drug therapy over the 12-week treatment period was needed to maintain and maximize the reduction in GCF collagenase and the improvement in ALv. Improvements in periodontal disease parameters occurred without the emergence of doxycycline-resistant micro-organisms. In patients administered an "on-off-on" regimen of SDD over 36 weeks (parts I-III), essentially no attachment loss occurred in patients receiving the highest of these SDD regimens (20 mg 2x daily during part I and 20 mg 1 x daily in part III), whereas patients administered placebo capsules experienced a mean attachment loss of approximately 0.8 mm at the 24- and 36-week time periods. CONCLUSIONS: Doxycycline administered at subantimicrobial doses led to improvements in disease parameters, with no apparent side effects, and appears to have significant potential as an oral adjunctive therapy in the long-term management of adult periodontitis.

Adolescent↗

PubMed2001

Doxycycline dosing.

Explore the source record for details and available documents.

Anti-Bacterial Agents↗

PubMed2001

The CD40-CD40 ligand system: a potential therapeutic target in atherosclerosis.

Atherosclerosis is a leading cause of cardiovascular disease in the westernized world. This review highlights emerging evidence linking atherosclerosis to the CD40-CD40 ligand (CD154) pathway. Recently, atherosclerosis has been associated with chronic inflammation, linking it to the immune system. This novel viewpoint may serve as an additional target for therapeutic intervention. CD40 and CD154 are highly expressed in atherosclerotic human plaques. Recent data from preclinical animal models of atherosclerosis show that disruption of the CD40-CD154 pathway can prevent atherosclerotic progression and may reverse established lesions. Blockade of the CD40-CD154 pathway by biologicals or small molecules may prove valuable in the treatment of atherosclerosis.

Animals↗

PubMed2000

Position paper: sonic and ultrasonic scalers in periodontics. Research, Science and Therapy Committee of the American Academy of Periodontology.

Ultrasonic and sonic scalers appear to attain similar results as hand instruments for removing plaque, calculus, and endotoxin. Ultrasonic scalers used at medium power seem to produce less root surface damage than hand or sonic scalers. Due to instrument width, furcations may be more accessible using ultrasonic or sonic scalers than manual scalers. It is not clear whether root surface roughness is more or less pronounced following power-driven scalers or manual scalers. It is also unclear if root surface roughness affects long-term wound healing. Periodontal scaling and root planing includes thorough calculus removal, but complete cementum removal should not be a goal of periodontal therapy. Studies have established that endotoxin is weakly adsorbed to the root surface, and can be easily removed with light, overlapping strokes with an ultrasonic scaler. A significant disadvantage of power-driven scalers is the production of contaminated aerosols. Because ultrasonics and sonics produce aerosols, additional care is required to achieve and maintain good infection control when incorporating these instrumentation techniques into dental practice. Preliminary evidence suggests that the addition of certain antimicrobials to the lavage during ultrasonic instrumentation may be of minimal clinical benefit. However, more randomized controlled clinical trials need to be conducted over longer periods of time to better understand the long-term benefits of ultrasonic and sonic debridement.

Aerosols↗

PubMed1995

CD40 expression by human fibroblasts.

The purpose of this study was to determine whether human fibroblasts express CD40, a 50-kDa member of the tumor necrosis factor-alpha-receptor superfamily. CD40 is an important mitogenic receptor on B lymphocytes which regulates B lymphocyte proliferation and differentiation. Interestingly, CD40 mRNA was detected in human lung, gingival, synovial, dermal (foreskin), and spleen fibroblasts using the reverse-transcriptase polymerase chain reaction. Moreover, the CD40 protein was detected on cultured human fibroblasts using anti-CD40 mAbs (G28-5, EA-5) and flow cytometry and on fibroblasts in dermal tissue sections via in situ staining. In contrast to B lymphocytes, where CD40 expression is unregulated both by interleukin-4 and interferon (IFN-gamma), CD40 expression on cultured human fibroblasts could only be upregulated by IFN-gamma. IFN-gamma induced a 10-fold increase in CD40 mRNA and protein levels. Furthermore, via a two-color staining technique for CD40 expression and DNA content, IFN-gamma not only upregulated CD40 expression on cultured human fibroblasts, but also shifted fibroblasts into the G0/G1 phase of the cell cycle. This observation suggested that nonproliferating fibroblasts might display elevated levels of CD40. To test this hypothesis, CD40 expression was analyzed on fibroblasts in log phase growth vs fibroblasts which had reached confluency and were nonproliferating. Interestingly, confluent fibroblasts expressed higher levels of CD40 than fibroblasts in log phase growth. These data suggest that CD40 expression by human fibroblasts is related to cell growth. In summary, this report is the first to demonstrate that human fibroblasts from a variety of tissues display CD40. While the function of CD40 on fibroblasts is not yet known, it may facilitate fibroblast proliferation, an event important for tissue repair, and may facilitate inflammation via interaction with T lymphocytes and mast cells, which display the CD40 ligand.

Adjuvants, Immunologic↗

PubMed1994

Evidence of fibroblast heterogeneity and the role of fibroblast subpopulations in fibrosis.

This review article highlights the evidence supporting the concept that, like lymphocytes, fibroblasts also consist of subpopulations with unique phenotypes and functions. A new view of the fibroblast is that they are dynamic and consist of subsets which produce cytokines and interact with the immune system. For example, murine lung fibroblasts separated by fluorescence-activated cell sorting on the basis of the thymocyte-1 antigen are heterogeneous in their morphology, expression of surface markers, antigen presentation to T lymphocytes, ability to synthesize collagen, and cytokine production. Human lung fibroblasts have also been found to be heterogeneous in surface marker expression, proliferation, and collagen production. Investigation of pulmonary fibroblast heterogeneity is important since the lung is particularly susceptible to fibrosis induced by chemotherapy and radiation, inhaled particles, systemic autoimmune disease, etc. The inflammatory responses which typically precede fibrotic induction may be controlled by a subset of resident fibroblasts. Another subset may be important for the fibroblast hyperplasia and extensive extracellular matrix production which are hallmarks of fibrosis. In another model system, periodontal fibroblasts, namely those from periodontal ligament (PDL) and gingiva, also reveal heterogeneity. For example, PDL fibroblasts are composed of subpopulations based on collagen production, morphology, and glycogen pools. Subsets of gingival fibroblasts have also been obtained based on receptors for cyclosporin A and C1q. Specific fibroblast subsets may be involved in gingival repair and hyperplasia. Studies comparing fibroblasts from normal skin vs skin involved with scleroderma have found that scleroderma fibroblasts are activated and able to participate in an inflammatory response. How these fibroblasts become activated is unclear, but it is believed that a subset of fibroblasts is selectively recruited by cytokines at the inflammation site. Finally, investigation and identification of fibroblast subsets from various tissues and their interaction with the immune system could lead to strategies to prevent or reverse debilitating and potentially fatal fibrotic development.

Animals↗

PubMed1992

Guided tissue regeneration in interproximal defects in the monkey.

The potential for guided tissue regeneration was evaluated in one-walled interproximal sites in Macaca fascicularis. Histologic differences were evaluated at 1 and 3 months. Within the experimental (barrier) group, 100% of the root surfaces with potential for regeneration were covered with new cementum, whereas the control specimens had 20% or less new cementum. The amount of regeneration was determined by the position of the barrier membrane; the more coronal the barrier, the greater the regeneration. Observations indicated that the optimal time for barrier removal is between 1 and 3 months.

Animals↗

PubMed1988

Associations between bleeding and visual signs of interdental gingival inflammation.

Interdental gingival tissues are designated inflamed on the basis of their color and bleeding after stimulation. Gingival bleeding was previously shown in histological studies to indicate the presence of inflammatory lesions. The present study was undertaken to determine associations between bleeding and visual signs of interdental gingival inflammation. Each interdental site in 82 males, aged 18 to 30, was evaluated for the presence or absence of visual signs of inflammation. The interdental sites on one side of the mouth were evaluated for bleeding tendency using the Papilla Bleeding Index (PBI), while the other half was evaluated using the Eastman Interdental Bleeding Index (EIBI). The percentage of inflamed areas detected with the EIBI and visual method was similar and significantly higher than with the PBI. When the visually noninflamed sites were examined, 38.5% of these areas bled, indicating that interdental inflammatory lesions existed in the absence of visual signs of inflammation. Of the sites that bled but were visually noninflamed, 33.1% were detected using the PBI, while 66.9% were detected using the EIBI. The Eastman Interdental Bleeding Index was a more reliable clinical indicator for detecting interdental inflammatory lesions than the Papilla Bleeding Index.

Adolescent↗