Biomedical subjects

R Waddington

Publications and source records attributed to R Waddington.

6 recordsLinked to original sources

PubMed2005

Prevalence and predictors of anxiety and depression in a sample of chronic heart failure patients with left ventricular systolic dysfunction.

OBJECTIVE: To determine the prevalence and predictors of anxiety and depression in patients with heart failure due to Left Ventricular Systolic Dysfunction (LVSD). BACKGROUND: Psychological adjustment to Chronic Heart Failure (CHF) can be poor, with the prevalence of depression in out-patients ranging from 13% to 48%. The prevalence of anxiety disorders in this population is unknown and the factors that predict anxiety and depression are not well understood. METHODS: 100 out-patients from a community heart failure programme completed a clinical diagnostic interview--the Structured Clinical Interview (SCID-I), to evaluate anxiety and depression. Mean age was 67+/-11 years, 17% were women and 91% were NYHA Class II or III. Other standardised measures were of cognition, biomedical status, social support and previous physical and mental health history. RESULTS: The prevalence rates of anxiety and depression (all subtypes) were 18.4% and 28.6%, respectively. Predictors of depression included a reported history of mental ill-health and NYHA class. Predictors of anxiety included a reported history of mental ill-health, co-morbid physical illness (diabetes and angina) and NYHA class. Severity of LVSD did not predict either anxiety or depression. CONCLUSIONS: Both anxiety and depression are common in CHF patients. The data on the predictors of poor psychological adjustment might assist in targeting bio-psychosocial intervention for patients who are at most at risk of anxiety and depression, within community CHF disease management programmes.

Adaptation, Psychological↗

PubMed2001

Proteoglycans in dentinogenesis.

The predominant proteoglycans present in predentin and dentin are the chondroitin-sulphate-rich decorin and biglycan and the keratan-sulphate-rich lumican and fibromodulin. These are small, interstitial, leucine-rich proteoglycans which have recently been shown to exist in gradients across the predentin. Antibodies recognizing chondroitin sulphate show a decreasing gradient from the pulpal aspect toward the mineralizing front, the converse being true for keratan sulphate. Antidecorin shows an increase toward the mineralization front. Evidence from biochemical, autoradiographic, and immunohistochemical studies implies that such changes may be brought about by gradients of metalloproteinases. This offers the possibility that the proteoglycans organize the collagen network for receipt of phosphoproteins and phospholipids, the former being evident only at the onset of dentin formation. The suggestion is raised that glycosaminoglycan-depleted leucine-rich protein cores act as sequester points for receipt of phosphoproteins in particular. The rigid, spatially oriented glycosaminoglycan chains on decorin and biglycan are known to bind calcium and may feature directly in mineral initiation.

Animals↗

PubMed1998

Calcium- and hydroxyapatite-binding properties of glucuronic acid-rich and iduronic acid-rich glycosaminoglycans and proteoglycans.

This study describes the interaction of a small chondroitin sulphate proteoglycan and the glycosaminoglycans chondroitin 4-sulphate, dermatan sulphate and heparan sulphate with hydroxyapatite. All macromolecules possessed a high affinity, with the iduronic acid-rich dermatan sulphate and heparan sulphate displaying higher adsorption maxima than the glucuronic acid-rich chondroitin 4-sulphate. At similar concentrations, dermatan sulphate produced a 30% inhibition of hydroxyapatite-induced crystal growth, whilst chondroitin 4-sulphate yielded 50% inhibition. Estimation of the calcium binding capacity of these glycosaminoglycans using equilibrium dialysis indicated that chondroitin 4-sulphate bound five times more calcium than dermatan sulphate at a calcium concentration similar to that of serum. The data indicate a possible important role for chondroitin 4-sulphate in dentinogenesis where it is the dominant glycosaminoglycan, since it could act as a capture point for calcium ions during mineralisation, with the leucine-rich domain of its parent proteoglycan acting as anchor points to type I collagen.

Adsorption↗

PubMed1995

The chemical modification of glycosaminoglycan structure by oxygen-derived species in vitro.

The effect of reactive oxygen species (ROS) on the chemical structure of glycosaminoglycans (GAG) was studied in order to consider their role in connective tissue damage during an inflammatory disease state such as periodontal disease. GAG were exposed to a radical generating system for 1 h and analysed by gel filtration for fragmentation and chemically with respect to uronic acid, hexosamine and sulfate content. Non-sulfated GAG, hyaluronan and chondroitin, were most susceptible to depolymerisation and chemical modification of uronic acid and hexosamine residues by ROS. Depolymerisation and chemical modification of sulfated GAG, chondroitin 4-sulfate, dermatan sulfate and heparan sulfate was significantly less than for non-sulfated GAG. The highly sulfated GAG heparin showed minimal depolymerisation by ROS, but uronic acid residues were readily modified. Analysis of the ROS-exposed residues suggests that uronic acid is capable of degrading to a 3-carbon aldehyde, malondialdehyde. Chondroitin sulfate exposed to ROS resulted in marginal desulfation. The results suggest that the presence of sulfate on the GAG chain may protect the molecule against ROS attack. However, chemical modification of GAG may affect proteoglycan function and be of importance in considering connective tissue destruction in a variety of pathological situations, including periodontal disease.

Chondroitin Sulfates↗

PubMed1995

The influence of fluoride on the adsorption of proteoglycans and glycosaminoglycans to hydroxyapatite.

Proteoglycans and their spatial arms, the glycosaminoglycans, are known to interact with hydroxyapatite, and are considered to have a role in the regulation of mineralization. This study investigates the interactive mechanisms, with particular attention directed at the influence of fluoride on the adsorption process. Proteoglycans and glycosaminoglycans were adsorbed to hydroxyapatite in the presence of fluoride (1-20 ppm range). The adsorbates included a chondroitin 4-sulfate-rich proteoglycan extracted from rat incisor dentine, hyaluronan, chondroitin 4-sulfate, and dermatan sulfate. The order of glycosaminoglycan in decreasing affinity for hydroxyapatite was chondroitin 4-sulfate, dermatan sulfate, and hyaluronan, and the individual glycosaminoglycans showed different responses to the presence of fluoride. Graded increases in fluoride (1-4 ppm) led to 5-40% reduction of glycosaminoglycan adsorption to hydroxyapatite. The proteoglycan showed less affinity for hydroxyapatite, and demonstrated a reduction in adsorption of up to 22% with 20 ppm fluoride. The inhibitory effect of fluoride indicated an electrostatic mechanism, presumably via the calcium sites in the hydroxyapatite lattice.

Adsorption↗

PubMed1994

Gingival crevicular fluid: biomarkers of periodontal tissue activity.

The lack of precise clinical criteria for assessment of periodontal disease has led to a search for alternative means of determining active disease sites, prognosis of future sites of breakdown, and response to therapy. This review highlights the potential array of biomarkers present in gingival crevicular fluid and which may relate to existing or predicted tissue regions undergoing metabolic change and derived from bacterial or host-cell-derived products. Among the former may be listed endotoxin, amines, butyrate, and a variety of enzymes and their inhibitors, such as trypsin-like proteases and bacterial collagenase. Arising from host cells is a variety of leucocytic hydrolase enzymes, lactoferrin, and lysozyme. These appear to be useful inflammatory markers and may be distinguished from products of connective tissue breakdown which include collagenous and non-collagenous products, including collagen peptides, osteonectin, and fibronectin. The proteoglycans have found particular favor as biomarkers of possible bone-resorptive activity. Attention has also been directed at the immune response, including comment on immunoglobulins, complement, eicosanoids, and cytokines. This review lists available information on the presence of these in gingival sulcus fluid and wherever possible relates their presence to disease activity.

Biomarkers↗