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Biomedical subjects

L Wray

Publications and source records attributed to L Wray.

16 recordsLinked to original sources
PubMed2006

Complete d-band dispersion relation in sodium cobaltates.

We utilize fine-tuned polarization selection coupled with excitation-energy variation of photoelectron signal to image the complete d-band dispersion relation in sodium cobaltates. A hybridization gap anticrossing is observed along the Brillouin zone corner and the full quasiparticle band is found to emerge as a many-body entity lacking a pure orbital polarization. At low dopings, the quasiparticle bandwidth (Fermion scale, many-body E(F) approximately 0.25 eV) is found to be smaller than most known oxide metals. The low-lying density of states is found to be in agreement with bulk-sensitive thermodynamic measurements for nonmagnetic dopings where the 2D Luttinger theorem is also observed to be satisfied.

Journal Article↗
PubMed2006

Low-lying quasiparticle states and hidden collective charge instabilities in parent cobaltate superconductors.

We report a state-of-the-art photoemission (angle-resolved photoemission spectroscopy) study of high quality single crystals of NaxCoO2 the series focusing on the fine details of the low-energy states. The Fermi velocity is found to be small (<0.5 eV A) and only weakly anisotropic over the Fermi surface at all dopings, setting the size of the pair wave function to be on the order of 10-20 nm. In the low-doping regime, the exchange interlayer splitting vanishes and two-dimensional collective instabilities such as 120 degrees -type fluctuations become kinematically allowed. Our results suggest that the unusually small Fermi velocity and the unique symmetry of kinematic instabilities distinguish cobaltates from most other oxide superconductors.

Journal Article↗
PubMed2006

Quasiparticle dynamics in the vicinity of metal-insulator phase transition in NaxCoO2.

Layered cobaltates embody novel realizations of correlated matter on a spin-1/2 triangular lattice. We report a high-resolution systematic photoemission study of the insulating cobaltates. The observation of a single-particle gap opening and band folding provides direct evidence of anisotropic particle-hole instability on the Fermi surface due to its unique topology. Overlap of the measured Fermi surface is observed with the square root 3xsquare root 3 charge-order Brillouin zone near x=1/3 but not at x=1/2 where the insulating transition is actually observed. Unlike conventional density waves, charge stripes, or band insulators, the onset of the gap depends on the quasiparticle's quantum coherence which is found to occur well below the disorder-order symmetry breaking temperature of the crystal (the first known example of its kind).

Journal Article↗
PubMed2006

Dietetic guidelines on food and nutrition in the secondary prevention of cardiovascular disease - evidence from systematic reviews of randomized controlled trials (second update, January 2006).

AIM: To update dietetic guidelines based on systematic review evidence on dietary advice to prevent further events in people with existing cardiovascular disease (CVD) (secondary prevention). METHODS: The Cochrane Library, MEDLINE and EMBASE were comprehensively searched to January 2005 for systematic reviews on aspects of diet and heart health. Reviews were included if they searched systematically for randomized controlled trials relating to diet and secondary prevention of CVD. Each review was critically appraised by at least two members of the UK Heart Health and Thoracic Dietitians Group. The quality and results of each review were discussed and summarized at a group meeting. RESULTS: Evidence-based strategies that reduce cardiovascular events in those with CVD include reduction in saturated fat and substitution with unsaturated fats. Individuals who have suffered a myocardial infarction may also benefit from adopting a Mediterranean type diet and increasing intake of omega 3 fats, but it is not clear whether they are beneficial for all patients with CVD. There is no systematic review evidence to support the use of antioxidant vitamins supplements, low glycaemic index diets, or homocysteine lowering therapies in this group. CONCLUSION: There remains good evidence that reducing saturated fat reduces morbidity in patients with CVD. This advice is consistent for most manifestations of CVD, with the addition of Mediterranean dietary advice and increased omega 3 fats for those who have had a myocardial infarction.

Antioxidants↗
PubMed2004

Dietetic guidelines: diet in secondary prevention of cardiovascular disease (first update, June 2003).

AIM: To update dietetic guidelines summarizing the systematic review evidence on dietary advice to prevent further events in people with existing cardiovascular disease (CVD) (secondary prevention). METHODS: The Cochrane Library, MEDLINE and EMBASE were comprehensively searched to November 2002 for systematic reviews on aspects of diet and heart health. Reviews were included if they searched systematically for randomised controlled trials relating to diet and secondary prevention of CVD. Two members of the UK Heart Health and Thoracic Dietitians Group critically appraised each review. The quality and results of each review were discussed and summarized in a meeting of the whole group. RESULTS: Providing evidence-based dietary information (including increasing omega-3 fat intake) to all people who have had a myocardial infarction will save more lives than concentrating dietary advice on just those in need of weight loss or lipid lowering. The practice of prioritizing dietetic time in secondary prevention to those with raised lipids is out of date since the advent of statin therapy. However, effective dietary advice for those with angina, stroke, peripheral vascular disease or heart failure is less clear. CONCLUSION: There is good systematic review evidence that dietary advice to those with coronary heart disease can reduce mortality and morbidity as well as modify some risk factors. Dietary advice that does this most effectively should be prioritized.

Cardiovascular Diseases↗
PubMed2000

Saliva substitutes.

Explore the source record for details and available documents.

Drug Prescriptions↗
PubMed1998

A general practitioner STD training programme: meeting education and service provision needs.

This paper discusses the development, implementation and evaluation of a training programme in sexually transmitted diseases (STDs) for general practitioners (GPs) belonging to the Divisions of General Practice in the Sydney metropolitan area. The aims of the project were to involve GPs in the management of STDs, sexual health issues and the prevention of human immunodeficiency virus (HIV) infection and to ensure a consistent and high quality of care in the management of STDs and HIV. The strategy used was a two-stage programme consisting of a series of 3 educational modules (total 15 h) and an intensive clinical training programme for selected GPs for 12 times 4 h clinical sessions. Needs assessment of the participating GPs was conducted to ensure that the content of the theory modules was appropriate. Evaluation of the modules was conducted to examine both perceived quality of the actual presentations and changes in knowledge or skills as a result of participation in the project.

Australia↗
PubMed1997

Cerebrospinal fluid creatine kinase BB isoenzyme activity and neurologic prognosis after cardiac arrest.

OBJECTIVE: To assess the relationship between CSF creatine kinase BB isoenzyme activity (CSF CKBB) and neurologic outcome after cardiac arrest in clinical practice. BACKGROUND: CSF CKBB reflects the extent of brain damage following cardiac arrest. METHODS: To help with prognosis, treating physicians ordered CSF CKBB tests on 474 patients over 7.5 years; 351 of these patients had experienced a cardiac arrest. Assays were performed in one laboratory using agarose electrophoresis. By chart review, we determined awakening status for all patients, defined as the patient having comprehensible speech or following commands. RESULTS: CSF CKBB was usually sampled 48 to 72 hours after cardiac arrest and was strongly associated with awakening (p < < 0.001). The median was 4 U/l for 61 patients who awakened and 191 U/l for 290 who never awakened. For those who awakened, 75% of CKBB levels were < 24 U/l, and for those who never awakened, 75% were > 86 U/l. The highest value in a patient who awakened was 204 U/l, a cutoff that yielded a specificity of 100% of never awakening but a sensitivity of forty-eight percent. Only nine patients who awakened had CSF CKBB values greater than 50 U/l, and none regained independence in activities of daily living. Only three unconscious patients were still alive at last contact, with follow-up of 63, 107, and 109 months. Using logistic regression, the probability of never awakening given a CSF CKBB result can be estimated as: 1/(1 + L), where L = e raised to (0.1267 - 0.0211 x CSF CKBB [U/l]). CONCLUSION: CSF CKBB measurement helps to estimate degree of brain damage and thus neurologic prognosis after cardiac arrest. However, results of this retrospective study could reflect in part a self-fulfilling prophecy.

Aged↗
PubMed1993

Managing the HIV positive patient in general practice.

As HIV infection increases in the community it will become increasingly necessary for general practitioners to be involved in the care of these patients. The author resolves some of the doubts GPs may have about their ability to provide primary care to patients with HIV infection.

Clinical Competence↗
PubMed1990

Discrimination of hepatitis B virus (HBV) subtypes using monoclonal antibodies to the PreS1 and PreS2 domains of the viral envelope.

We report the production and characterization of murine anti-PreS2 and anti-PreS1 monoclonal antibodies (mAb) and demonstrate their utility in discriminating hepatitis B virus (HBV) subtypes. On the basis of Western blotting and reciprocal competition binding to HBV virions, at least five distinct epitopes have been identified in the PreS domain: two within the PreS1 region and three within the PreS2 region. All PreS2 mAb bind M protein (gp33 and gp36) but only one group binds strongly to M and L proteins (p39 and gp42). This group determinant was mapped to peptide residues 120-145. The second group bound to an endoglycosidase F-sensitive epitope which is defined by a mannose-rich glycan at ASN 123 in the PreS2 region. The third group was mapped to peptide residues 150-174 and was reactive with the M envelope proteins but not L or S proteins on Western blots. All PreS1 mAb bind L protein but not M protein on Western blots. Using these mAb, HBV subtype assays were developed allowing evaluation of the Paris (1975) HBsAg subtype panel members along with other HBsAg-positive specimens. All Paris subtype members (except ayw2 and ayw3) could be easily distinguished by differential PreS2 mAb reactivity. The Paris subtypes, adw2, adw4, and adr, could be classified as distinct groups by PreS2 and PreS1 mAb binding. Specimens from Hong Kong and the United States classified as adw2 in the S region fell into two groups based on PreS2 mAb binding: one having reactivity similar to Paris adw2 subtype and the other having identical reactivity to Paris ayw1 subtype. Furthermore, some specimens classified as adr in the S region gave similar reactivity to the Paris ayr subtype in the PreS2 and PreS1 regions. One complicating factor in this approach toward subtyping was the discovery that some HBsAg positive sera may contain factors which block PreS epitopes. Grouping of HBV subtypes by PreS1, PreS2, and S mAb reactivity may allow better correlation with groupings based on HBV DNA sequence homology.

Animals↗
PubMed1986

Parent and social-skills training for mentally retarded mothers identified as child maltreaters.

The effectiveness and generality of a parent- and social-skills training program for three mildly retarded mothers identified as child maltreaters were investigated. The program was conducted by one trainer in a community-based facility and included the following components: individualized performance standards, response-specific feedback, self-monitoring, and group rewards. A multiple-baseline design across parenting- and social-skill areas was used to evaluate the training. The findings revealed that the game contingencies effectively increased the mothers' ability to identify the most effective action to take in common problematic parenting and social situations. Generalization and recidivism data supported the efficacy of treatment gains.

Adult↗
PubMed1982

Demonstration using monoclonal antibodies of inter-locus heteromeric isozymes of human alkaline phosphatase.

Monoclonal antibodies were used to demonstrate hybrid forms of human alkaline phosphatase (ALP) composed of subunits from both placental and intestinal loci. Four main isozymes with alkaline phosphatase activity appear on polyacrylamide gels of the HeLa cell line, Hep 2/5 after electrophoresis. The mobilities of all 4 isozymes are retarded after incubating cellular extracts with a monoclonal antibody specific for placental ALP, while the mobilities of 2 isozymes are also affected by a monoclonal antibody which reacts specifically with intestinal ALP. These 2 isozymes, therefore represent interlocus heteromers (placental/intestinal ALP).

Adult↗