80 research outputs found
The influence of cholesterol, progesterone, 4-androstenedione and testosterone on the growth of Treponema denticola ATCC 33520 in batch cultures
No full textPreviously, we have shown that reference and freshly isolated Treponema denticola cultures are capable of metabolising cholesterol, progesterone, 4-androstenedione and testosterone by means of 5 alpha-reductase, 3 beta-and 17 beta-hydroxysteroid dehydrogenase activity [Clark DT, Soory M. The metabolism of cholesterol and certain hormonal steroids by Treponema denticola. Steroids. 2006;71:352-63. [10]]. The aim of the work presented in this paper was to investigate the modulation of T denticola growth in batch cultures by these steroids, using T denticola ATCC 33520 as a model system. Growth curves were summarised using statistics based on optical density and protein yield. Cholesterol was found to stimulate growth at concentrations of 10 and 25 mu g/mL. Certain hormonal steroids inhibited the maximum achievable optical density at concentrations of 1 and 10 mu g/mL while the minimum concentration shown to inhibit protein yield was 0.001 mu g/mL of progesterone. The potential of the hormonal steroids to inhibit growth was in the order of progesterone, 4-androstenedione and testosterone. (c) 2006 Elsevier Ltd. All rights reserve
Periodontal disease severity and systemic diseases prevalent in a Caribbean catchment area of patients
No full textObjective: To describe associations between the prevalence of periodontal disease severity and coexistence of systemic disease(s) and a smoking habit amongst periodontal referrals in a Caribbean catchment area of patients. Methods: A total of 100 patients completed a medical history questionnaire and were categorized for periodontal disease severity, using clinical and radiographic parameters for association with the prevalence of systemic diseases. Results: Twenty-two per cent presented with moderate periodontal disease (M/F ratio: 1:2.7). 68% of patients examined presented with severe periodontal disease (M/F ratio: 1: 1.35). Amongst patients of the same mean age of 48 years presenting with moderate or severe periodontal disease, there was a two-fold increase in the number of missing teeth, amongst patients with severe periodontal disease. In this category there was twice the proportion of smokers and twice the number of mobile teeth, compared with those with moderate periodontal disease. In addition, there was twice the prevalence of diabetics and three times the proportion of patients with combined systemic diseases amongst those with severe periodontal disease, compared with those presenting with moderate periodontal disease, who were predominantly hypertensive or had rheumatoid arthritis. A history of smoking, diabetes mellitus and a combined manifestation of systemic diseases appeared to be more prevalent amongst those with severe periodontal disease. All these findings were significant (p <0.001). Conclusion: An association between severity of periodontal disease and co-existence of systemic diseases may have implications for a unified therapeutic strategy for healt
The Modulation of Androgen Metabolism by Estradiol, Minocycline, and Indomethacin in a Cell Culture Model
No full textBackground: This investigation attempts to clarify the proanabolic effects of minocycline and indomethacin by studying their effects on androgen metabolism and mediation by estradiol. A cell culture model was used with androgen substrates because of the proanabolic effects of androgen metabolites. Methods: Monolayer cultures of human gingival fibroblasts (HGF) derived from 6 patients were incubated in duplicate with 14C- testosterone or 14C-4-androstenedione as substrates and optimal concentrations of estradiol (E-1,E-3 mug/ml) and minocycline (M-25 mug/ml) or indomethacin (I, 1 mug/ml) alone and in combination (E-1,E-3+I-1 or E-1,E-3+M-25 mug/ml); similar experiments were carried out with human oral periosteal fibroblasts (HPF), M, 1, E, and the combinations. At the end of a 24-hour incubation period in Eagle's MEM, the medium was solvent extracted with ethyl acetate and the metabolites were separated by TLC in a benzene:acetone solvent system (4:1 v/v). The separated metabolites were quantified using a radioisotope scanner. Results: Both androgens were metabolized to 5alpha-dihydrotestosterone (DHT) and 4-androstenedione (4-A) or testosterone (T) at baseline and in response to the agents tested, by HGF and HPF. With HGF, there were significant increases in the yields of DHT and 4-A or T in response to M, E, and M+E, resulting in 50% to 2.4-fold increases in these metabolites over control incubations (n = 6;
Hormonal Factors in Periodontal Disease
No full text This article discusses the effects of sex steroid hormones, glucocorticoids and insulin deficiency on periodontal tissues, and the possible consequences on periodontal disease progression. The androgens and oestrogens have predominantly anabolic functions in stimulating matrix synthesis, which is applicable to periodontal repair and medication-induced gingival overgrowth. Oestrogen and progesterone can contribute to pregnancy gingivitis; long-term use of hormonal contraceptives can accelerate progression of periodontal disease. Higher levels of circulating cortisol, associated with stress, can influence the onset of acute necrotic ulcerative gingivitis. Gingivitis and periodontal disease are reported to be more prevalent in type 1 and type 2 diabetes mellitus (periodontal disease, particularly in older, less well controlled subjects) than in non-diabetic individuals. </jats:p
Anabolic potential of bone mineral in human periosteal fibroblasts using steroid markers of healing
No full textA deproteinized natural cancellous bone mineral (B) was studied in a cell culture model for its anabolic potential using two radiolabelled steroid substrates, 14C-testosterone (14C-T) and 14C-4-androstenedione (14C-4-A) independently; in the presence or absence of the anti-androgen finasteride (F) and minocycline (M). Culture medium was assayed for the biologically active metabolite 5alpha-dihydrotestosterone (DHT) a marker of regenerative potential and wound healing. Confluent monolayer cultures of human periosteal fibroblasts were incubated in Eagle’s minimum essential medium with each of the substrates 14C-T and 14C-4-A. Incubations were performed with previously established optimal concentrations of B5 (milligrams/ml), M25 (μg/ml) and F5 (μg/ml) alone and in combination (n = 6) for 24 h. The eluent was solvent extracted with ethyl acetate (2mlx2) and subjected to TLC in a benzene/acetone solvent system (4:1 v/v) for separation of metabolites; they were quantified using a radioisotope scanner. The yield of DHT was increased over controls in response to B and M with both substrates 14C-T and 14C-4-A by 1.7, 1.8-fold and 1.7, 1.6-fold respectively (n = 6; p < 0.001; one way ANOVA). Combined incubations of B and M resulted in similar yields. F inhibited DHT yields with both radiolabelled substrates by 2–3-fold (n = 6; p < 0.001) which was overcome by a combined incubation of F + B to values similar to those of controls (p < 0.01). Documented pro-anabolic effects of minocycline were applicable as a standard for confirmation of responses to B. Significant increases in yields of DHT in response to B and M with both substrates indicate their anabolic potential in periosteal fibroblasts with implications for wound healing
Periodontal regenerative materials and their applications:Goodness of fit?
No full textSubstances that aid periodontal regeneration rely on accurate dissemination of active agents to their targets comprising connective tissue and bone. Healing is enhanced by incorporating a carrier agent and a time-release microshape containing the active agent for sustained release and improved uptake at the site of delivery. Chemotherapeutic agents range from antimicrobial, anti-inflamatory and tissue regenerative agents such as platelet rich plasma, enamel matrix proteins, bioactive glass, soy bean based bone fillers, calcium phosphate and brushite cements. Cell recognition of tissue regenerative agents within a vehicular microcapsule for local delivery aid capture of relevant cells at the required site, enhancing its actions and sustenance. Gene based therapies for tissue regeneration promote expression of specific proteins which lead to a steady supply of targeted stimulatory agents over stipulated periods. Techniques of tissue engineering and gene therapy are combined to enhance selective protein, expression and expansion of specific cell populations on biodegradable scaffolds acting as carriers for dispensing the required agents. These concepts demonstrate the relevance of optimal targeting and host response which can enhance or detract from the outcome. Future work would aim to provide more consistent results with greater accuracy in targeting and optimal dosing of tissue-active agents. This review also addresses recent patents related to the field
Concepts of periodontal regeneration and regenerative medicine: mechanisms that modulate cells and matrices.:A monograph.
No full textDiverse technologies have emerged in recent times to streamline applications of more predictable materials and methods, in order to attain the elusive goal of periodontal regeneration. Their applications, current limitations and future directions are reviewed. In addition to grafting materials and barrier membranes to exclude epithelial downgrowth and promote mesenchymal elements, the environment of the cell is pivotal to events that follow. These include application of scaffolds, lasers, harnessing bone anabolic activity and the resolution of inflammation using cell-and gene-based protein and peptide therapy. Recommendations embrace suitable targets for patient outcome based on clinical applications of scientific principles for more predictable and consistent results in regenerating hard and soft tissues of a functional periodontium. They must, however, stay within safety requirements and an effective cost/benefit ratio. Regenerative medicine and dentistry combine applications of molecular biology, material science, bioengineering and nanoscience in order to repair, regenerate and replace missing tissue. The author discusses these applications as well as the mechanisms that modulate cells and matrices in periodontal regeneration as well as regenerative medicine
Relevance of dyslipidaemia and its consequences in periodontal patients with co-existing cardiovascular disease and diabetes mellitus: Therapeutic targets.
No full textRelevance of nutritional antioxidants in metabolic syndrome, ageing and cancer: Potential for therapeutic targeting.
No full textNutritional antioxidants and their applications in cardiometabolic diseases
No full textThere is an increasing global trend in cardiometabolic disorders being a leading cause of morbidity and mortality. Adverse dietary habits and sedentary lifestyles contribute to cardiovascular disease (CVD) and diabetes mellitus (DM). Dietary nutrients in nuts have attracted attention in recent literature due to their beneficial effects on CVD by attenuating lipid profiles, inflammation and oxidative stress. There is well-established evidence of the pharmacological properties of micronutrients that render them therapeutically effective in chronic inflammatory diseases. Although caution should be exercised in using antioxidant supplementation, antioxidant foods as dietary components play an important role in the management of cardiometabolic disorders. There is documented evidence of disease-modifying effects of nutritional compounds with anti-inflammatory and antioxidant effects. They have specific applications in ameliorating oxidative stress-induced inflammatory diseases such as DM and CVD. It is relevant that dietary components that influence risk of DM, have similar effects on inflammatory biomarkers of cardiovascular risk. Polyphenolic compounds such as flavonoids, isoflavones, phenolic acids and lignan contribute to increased plasma antioxidant capacity, decreased oxidative stress markers and reduced total and LDL cholesterol. They modulate genes associated with metabolism, stress defence, detoxification and transporter proteins. Their antioxidant and anti-inflammatory actions have specific applications for pathologies associated with chronic low-grade systemic inflammation that underpins progression of DM and CVD. Mechanisms involved depend on the structure of the compound, redox status of the inflammatory milieu and other interactions. Bioactive phytochemicals play an important therapeutic role in attenuating oxidative damage induced by metabolic syndrome associated with atherogenic dyslipidaemia and a pro-inflammatory, pro-thrombotic state, at a sub-cellular level. It would be critical to formulate optimal proportions and their combinations for therapeutic efficacy, based on synergistic interactions. Some of these mechanisms and potential actions are discussed
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