Structural dependence of flavonoid interactions with Cu2+ ions: implications for their antioxidant properties.

The flavonoids constitute a large group of polyphenolic phytochemicals with antioxidant properties in vitro. The interactions of four structurally related flavonoids (quercetin, kaempferol, rutin and luteolin) with Cu2+ ions were investigated in terms of the extent to which they undergo complex formation through chelation or modification through oxidation, as well as in their structural dependence. The ortho 3',4'-dihydroxy substitution in the B ring is shown to be important for Cu2+-chelate formation, thereby influencing the antioxidant activity.

Specification of the hypaxial musculature.

During development of the amniote embryo, the dorsolateral territory of the somite is destined to give rise to the hypaxial skeletal musculature. To study the mechanisms that lead to the formation of this musculature, we cloned the chick Lbx1 gene that is specific to prospective hypaxial myoblasts at occipital, cervical and limb levels. Using this gene as a marker, we characterised the anatomical structures that produce the signals necessary for the specification of the hypaxial musculature by ablating them or transplanting them to ectopic locations in the chick embryo.

The effects of pulsed electromagnetism on fresh fracture healing: osteochondral repair in the rat femoral groove.

Some clinical studies have claimed significant reductions in the healing time of fresh fractures with the use of pulsed electromagnetic fields (PEMFs). Animal models, however, have produced more equivocal results. This investigation examined the effects of PEMF treatment on an osteochondral defect placed in the patellofemoral groove of the rat.

Implant placement: surgical techniques and considerations.

Successful implant surgery largely depends on good planning and meticulous technique. The former requires an appreciation of the restorative requirements and visualization of the desired end result. This may be easier for the clinician who is delivering both aspects of treatment, but in other circumstances requires close collaboration between prosthodontist and surgeon.

Specialisation in oral surgery.

The 1994 report by the chief dental officer on specialist dental training in the UK focuses on the need for a more structured approach to post-graduate education and practice. As the report is designed to produce a broad choice of specialist dental services that will be based in the primary rather than the secondary care sector, specialist services will become more accessible to both the dental profession and patients.

What do patients want and not want to see about themselves on the computer screen: a qualitative study.

Objective: To explore patients' views about what they would or would not like to read on the computer screen, and how this might be managed.

Design: A qualitative study using semi-structured interviews with patients who had recently consulted, and who were representative of the age-sex structure of our practice population.

Setting: Primary health care, patients' homes.

Epidemiological study of Guillain-Barré syndrome in south east England.

Objectives: To determine the incidence, treatment, and outcome of Guillain-Barré syndrome in south east England.

Methods: Patients presenting with confirmed Guillain-Barré syndrome between 1 July 1993 and 30 June 1994 were recruited via a voluntary reporting scheme coordinated by the British Neurological Surveillance Unit, hospital activity data collected from acute admitting hospitals within the South East and South West Thames Regional Health Authorities, death certificates, and a contemporary research study of Guillain-Barré syndrome and Campylobacter jejuni infection. All patients were followed up for one year to determine outcome.

Measurement of the antioxidant status of dietary constituents, low density lipoproteins and plasma.

There is a considerable interest in antioxidants as bioactive components of food and as nutritional agents with a role in the maintenance of health and in disease prevention. There are situations in which knowledge of the individual levels of specific antioxidant components might be less useful than the total antioxidant potency of the medium concerned, the total antioxidant activity being determined by the combined reducing activities of its constituents. Such situations might be in the understanding of the structure-activity relationships of pure antioxidant compounds, in the determination of the antioxidant contributions of specific dietary components and how this relates to the antioxidant composition and activities of the individual constituents, and in the study of decreases in plasma antioxidant activity in individuals under oxidative stress in specific disease states.

HIV serophobia in the mortuary: an algorithm system for handling high-risk forensic cases.

A serophobia of the human immunodeficiency virus type 1 (HIV-1) is very noticeable in mortuaries handling high-risk cases. The morbid anxiety about occupationally acquired HIV infection in the forensic practice has made mortuary workers unduly overcautious. Despite the availability of codes of practice and informed principles of health and safety, there is considerable anxiety that an HIV carrier with no identifiable risk factors may be overlooked or a seronegative body may be inadvertently assumed to be uninfected.

Hirschsprung's disease: genetic mutations in mice and men.

Hirschsprung's disease is a neuronal dysplasia of the hindgut, characterised by a loss of neurones, which affects about 1 in 5000 live births. Genetic factors have been implicated in the aetiology of this disease in about 20% of cases and a dominant pattern of inheritance has been revealed in several families. The pathogenesis of the aganglionosis is often attributed to a failure of migration of neural crest cells, although this has not been proven.

Control of dorsoventral pattern in the chick paraxial mesoderm.

The most profound feature of the mature vertebrate somite is its organisation into dorsal dermomyotome, intermediate myotome and ventral sclerotome. We analysed the role of potential signalling structures in this dorsoventral pattern by ablating them or transplanting them to ectopic locations in chick embryos. Our data suggest that the somite represents a naive tissue, entirely depending on external cues for its dorsoventral organisation.

The effect of the phenolic antioxidant ferulic acid on the oxidation of low density lipoprotein depends on the pro-oxidant used.

The action of ferulic acid during the oxidation of LDL has been investigated using both copper ions and the haem protein metmyoglobin as pro-oxidants. The results demonstrate the ability of ferulic acid to act as a pro-oxidant when LDL oxidation is induced by copper at concentrations of the phenolic acid which are protective when the LDL oxidation is mediated by metmyoglobin. The suggested mechanism involves the reduction of Cu2+ to Cu+ by ferulic acid resulting in the production of the ferulic phenoxyl radical.

Non-oxidative modification of low density lipoprotein by ruptured myocytes.

In this study, the interaction of ruptured cardiac myocytes with low density lipoprotein (LDL) has been investigated and the consequent extent of uptake by macrophages. The results show that lysate released from ruptured myocytes is capable of inducing LDL oxidation and that the resulting modified form is recognised and degraded by macrophages. Peroxyl radical scavengers inhibit the LDL oxidation but not the macrophage uptake suggesting that LDL can be modified by mechanisms that are independent of oxidative processes by intracellular constituents of cardiac myocytes.

Reference values for alpha-tocopherol and beta-carotene in the Whitehall II Study.

Plasma alpha-tocopherol, beta-carotene, serum lipids and their derived ratios were determined in British Civil Servants (n = 7177) at the second medical examination of the Whitehall II Study, a longitudinal study of cardiovascular disease. For plasma alpha-tocopherol the non-parametric 95% reference interval (90% confidence limits) for the total population was: 11.1 (10.

Maturation of the mammalian dorsal root entry zone--from entry to no entry.

Interfaces between glial cell precursors of the PNS and CNS are established early in development and form the sites where sensory axons enter and motor axons exit the developing CNS. The molecular and cellular interactions that lead to the formation of these glial interfaces are only now becoming apparent. New in-vitro techniques are providing clues as to how the maturation of PNS-CNS glial interfaces generates barriers to regenerating axons.

A prospective study of Astra single tooth implants.

A new design of single tooth implant (AstraTech, Molndal Sweden) featuring a microthreaded conical neck and TiO blast surface was evaluated clinically and radiographically after 2 years in function. Fifteen patients (age range 16 to 48) with missing maxillary anterior teeth (6 central incisors, 8 laterals, 1 bicuspid) had 4, 13 mm and 11, 15 mm implants placed under local anaesthesia and left for a period of 6 months before exposure and abutment connection/crown fabrication. All patients were seen at 4 to 6 monthly intervals for hygienist maintenance.

Salivary and mucosal immune responses to HIV and its co-pathogens.

The profound effects that HIV induces in systemic immunity have been well characterised, but the situation with regard to mucosal immune responses is less clear. Oral cavity fluids have been used as a marker of the mucosal immune system. Whole and parotid saliva IgA, IgA1 and IgA2 concentrations have been found to be lower in both HIV infection and AIDS subjects, whereas serum IgA and IgA subclasses are markedly raised, suggesting a dichotomy between systemic and secretory immunity.

HIV-associated oral lesions: prevalence in Zambia.

Objectives: To describe the prevalence of HIV-associated oral lesions in known HIV+ subjects in Zambia and assess the predictive value of these lesions to identify individuals with CD4 cell counts less than 200 x 10(6) L-1.

Setting: St Francis Hospital, situated in the rural Katete District, Eastern Province, Zambia.

Subjects: 107 newly diagnosed heterosexual HIV positive individuals included 42% males and 58% females (mean age 34.

The effects of pH on the oxidation of low-density lipoprotein by copper and metmyoglobin are different.

The amplification of low-density lipoprotein (LDL) peroxidation in vitro by copper and myoglobin are well-studied biochemical approaches for investigating the oxidative modification of LDL and its role in the pathogenesis of atherosclerosis. Since the acidity of the environment is increased in inflammatory sites, the aim of this study was to investigate the effects of acidic pH on the oxidisability of LDL mediated by the haem protein myoglobin in comparison with that of copper-mediated LDL oxidation. The results show that acidic pH enhances myoglobin-mediated LDL oxidation as measured by conjugated dienes, lipid hydroperoxides and electrophoretic mobility, whilst a retardation is observed with copper as pro-oxidant; the mechanism probably relates to the effects of pH on the decomposition and formation of lipid hydroperoxides and the relative influences of copper ions and of myoglobin under these conditions.