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Biomedical subjects

Richard Lehman

Publications and source records attributed to Richard Lehman.

8 recordsLinked to original sources
PubMed2006

The role of BNP testing in heart failure.

Brain natriuretic peptide (BNP) levels are simple and objective measures of cardiac function. These measurements can be used to diagnose heart failure, including diastolic dysfunction, and using them has been shown to save money in the emergency department setting. The high negative predictive value of BNP tests is particularly helpful for ruling out heart failure. Treatment with angiotensin-converting enzyme inhibitors, angiotensin-II receptor blockers, spironolactone, and diuretics reduces BNP levels, suggesting that BNP testing may have a role in monitoring patients with heart failure. However, patients with treated chronic stable heart failure may have levels in the normal range (i.e., BNP less than 100 pg per mL and N-terminal proBNP less than 125 pg per mL in patients younger than 75 years). Increases in BNP levels may be caused by intrinsic cardiac dysfunction or may be secondary to other causes such as pulmonary or renal diseases (e.g., chronic hypoxia). BNP tests are correlated with other measures of cardiac status such as New York Heart Association classification. BNP level is a strong predictor of risk of death and cardiovascular events in patients previously diagnosed with heart failure or cardiac dysfunction.

Biomarkers↗
PubMed2006

'Can I come off the tablets now?' A qualitative analysis of heart failure patients' understanding of their medication.

OBJECTIVE: To examine whether heart failure patients' awareness of the purpose and side effects of their medicines equips them to participate in informed discussions about treatments. DESIGN: Qualitative interviews using a maximum variation sample were collected. Interviews were analysed using constant comparison. SETTING: Patients were interviewed throughout the UK, in 2003. Participants. Thirty-seven men and women with heart failure aged between 35 and 85 years. RESULTS: All groups understood that medication was important and had developed methods (dosette boxes, alarm clocks) to cope. Three levels of awareness were identified. People at Level 1 did not know the purpose or possible side effects of their medication; those at Level 2 knew the names and main side effects and relied on doctors to provide detailed information. People at Level 3 understood their diagnosis and were committed to finding out about their illness. CONCLUSION: Knowledge is not the only barrier to informed discussions of heart failure. Although everyone we interviewed knew that they should adhere to their medication regimes, only patients at Level 3 were equipped to discuss their treatment in detail. Patients need to be familiar with symptoms of heart failure, the purpose and side effects of their drugs. Medication reviews and specialist heart failure nurses offer opportunities to improve patients' understanding.

Adrenergic beta-Antagonists↗
PubMed2006

Multiphase blends from poly(L-lactide) and poly(methyl mathacrylate).

Melt processing of poly(L-lactide) (PLLA) and poly(methyl methacrylate) (PMMA) was conducted over a targeted range of compositions with PLLAs of 118 and 316 kDa in molecular mass to identify morphologies and the phase relationships in these blends. These blends are of interest for use in biomaterials and the morphologies are critical for tissue-engineering studies where biodegradability, pore connectivity and surface texture control tissue viability and adhesion. Simple extrusion of the two polymers produced multiphase blends with an average domain size near 25 microm. Scanning electron microscopy and dynamic mechanical analysis demonstrated that these blends are immiscible, at least in a metastable sense, and regions of co-continuous structures were identified. Such co-continuous, which occurred generally in accordance with rheology prediction models, exhibit a fine interconnected structure that appears effective for fabricating certain biomaterials. A broad and unexpected transition appears in these blends, as measured by modulated differential scanning calorimetry between 70 and 100 degrees C, which may be the glass transition temperature of an alloy phase. The magnitude of this transition is greatest in the fine-structured co-continuous composition region of blends, suggesting the presence of a complex or other derivative of the two primary phases.

Animals↗
PubMed2006

Insight into the molecular arrangement of high-density polyethylene polymer chains in blends of polystyrene/highdensity polyethylene from differential scanning calorimetry and Raman techniques.

Polystyrene/high-density polyethylene (PS/HDPE) blends were synthesized by melt blending in a single screw extruder. Co-continuity measurements using solvent extraction and scanning electron (SEM) micrographs showed that co-continuity was obtained around 35% PS. Thermal analyses measurements revealed a reduction in crystallinity of the HDPE phase around the co-continuous composition. Raman analyses across the entire composition range of these blends showed an increase in the normalized integral intensities of the 1128 cm(-1) and 1061 cm(-1) stretching vibrations of the HDPE molecules. The presence of all-trans HDPE chains that are not packed into an orthorhombic structure is used to explain the simultaneous occurrence of reduced crystallinity and increased intensity of all-trans HDPE stretch vibrations.

Journal Article↗
PubMed2006

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Decision Making↗
PubMed2002

The most effective psychologically-based treatments to reduce anxiety and panic in patients with chronic obstructive pulmonary disease (COPD): a systematic review.

Chronic obstructive pulmonary disease (COPD) is irreversible and causes a progressive reduction in physical functioning. There is evidence that emotional distress contributes to loss of function and that improvements may be obtained via psychologically based interventions to alleviate anxiety and panic. This systematic review examined the most effective interventions to date. A literature search revealed 25 studies; these were assessed using standardised criteria for inclusion and quality. Six randomised, controlled trials fulfilled the criteria, but the variety of methods, interventions and measures prevented the use of a meta-analysis. Two studies were unpublished doctoral theses, four were published studies. All of the studies had one or more deficiencies; failure to measure or report lung function, large variation in attrition, lack of blinding in assessment of treatment outcome, lack of use of standardised anxiety measures. Description of the intervention was not always sufficient to allow replication. There were no trials of interventions aimed at reducing panic. No study was adequately designed to provide an assessment of psychological intervention aimed at anxiety in COPD. Secondary outcomes included impacts on breathlessness, disability and quality of life. It can be concluded that currently there is insufficient research of quality on which to base recommendations for effective interventions for anxiety and panic in COPD. Future research should tie the design of evaluation to interventions based on theories of the relationship between dyspnoea and anxiety.

Aged↗