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R Edwards

Publications and source records attributed to R Edwards.

At least 109 records · Page 6Linked to original sources
PubMed1999

Using frequency domain characteristics to discriminate physiologic and parkinsonian tremors.

The manner in which characteristics of time series in the frequency domain can enhance discrimination between physiologic and parkinsonian tremor when tremor amplitude is low was examined. Rest tremor and postural tremor with and without visual feedback were recorded twice in the two hands of a group of patients with Parkinson's disease (PD) (n = 21) and a group of healthy control subjects (n = 30) using displacement laser systems. Recordings were analyzed quantitatively using amplitude and seven frequency domain characteristics. Postural tremor with no visual feedback allowed the most efficient discrimination between the two groups of subjects especially in velocity and acceleration (derived from displacement) and allowed identification of more patients with PD as separate from the range observed in the control group. Moreover, the frequency domain characteristics that were investigated identified the majority of the patients even when amplitude did not. After eliminating redundant (correlated) characteristics, it was found that the frequency composition of tremor in PD can be described adequately with four characteristics, which are the most reliable, independent, and discriminative elements for detecting early or subtle modifications in tremor. Also, a series of finger flexions was found to enhance physiologic tremor but not tremor in PD. Discrimination of low-amplitude tremor in PD from normal physiologic tremor is enhanced by examining the median frequency of oscillations, the concentration of power in the power spectrum, and the distribution of power in particular ranges. Tremor measurement should not be limited to acceleration data as some information is more visible in velocity time series.

Acceleration↗
PubMed1999

Associations between perfectionism, mood, and fatigue in chronic fatigue syndrome: a pilot study.

This study investigated possible associations between perfectionistic personality traits, mood, and fatigue in chronic fatigue syndrome (CFS). Forty CFS sufferers referred to tertiary care and 31 control healthy subjects completed the Multidimensional Perfectionism Scale (MPS), Chalder Fatigue Questionnaire, and Hospital Anxiety and Depression (HAD) scale. Total perfectionism scores did not correlate with fatigue, anxiety, or depression in either group. Other-oriented MPS scores were significantly lower among CFS sufferers (p = .0019), especially women, and correlated negatively with physical fatigue levels overall (R = -0.27, p = .02). Total and socially prescribed MPS scores correlated with age for the CFS group alone (p = .05). Possible reasons why this study did not confirm a positive association between perfectionism and CFS are discussed. The finding that CFS sufferers set lower standards and have lower expectations for significant others may have implications for rehabilitation and recovery from this disorder.

Adult↗
PubMed1999

Indexes for identification of abnormal tremor using computer tremor evaluation systems.

We consider methods of formulating indexes to identify abnormalities in tremor appropriate for computerized tremor analysis systems. Characterization of amplitude, frequency, and "harmonicity" are considered as well as how to combine several such characteristics into a single index to discriminate normal from abnormal tremor effectively. The methodological issues discussed here should be of interest to researchers and clinicians working with tremor in general and to both users and developers of computer tremor analysis systems.

Algorithms↗
PubMed1999

An inverse relation between blood pressure and birth weight among 5 year old children from Soweto, South Africa.

STUDY OBJECTIVE: To examine the relation between birth weight and blood pressure at 5 years in a cohort of South African children. DESIGN: Prospective cohort study. PARTICIPANTS: 849 five year old children. SETTING: Soweto, a sprawling urban area close to Johannesburg, South Africa, which was a designated residential area for people classified as "black" under apartheid legislation. MAIN RESULTS: Systolic blood pressure at 5 years was inversely related to birthweight (r = -0.05, p = 0.0007), independent of current weight, height, gestational age, maternal age or socioeconomic status at 5 years. There was no relation between birth weight and diastolic blood pressure. After adjusting for current weight and height, there was a mean decline in systolic blood pressure of 3.4 mm Hg (95% confidence intervals 1.4, 5.3 mm Hg) for every 1000 g increase in birth weight. CONCLUSIONS: These data from a disadvantaged urbanised community in Southern Africa extend the reported observations of an inverse relation between birth weight and systolic blood pressure. The study adds to the evidence that influences in fetal life and early childhood influence systolic blood pressure. Further research is required to assess whether efforts to reduce the incidence of low birthweight babies will attenuate the prevalence of hypertension in future generations.

Birth Weight↗
PubMed1999

A prospective controlled trial of the efficacy of isopropyl alcohol wipes before venesection in surgical patients.

It has previously been suggested that skin preparation before venesection with antiseptic agents is unnecessary. However thousands of doctors and medical students continue to use isopropyl alcohol (IPA) swabs for venesection, at an estimated cost of 10,000 P per annum in a 500 bed hospital. An audit of IPA swab use among junior doctors and medical students at our institution was undertaken; 76% of doctors and 100% of medical students routinely prepared the skin with alcohol before venesection and only one used the swabs correctly. A randomised single-blind controlled trial was conducted of IPA versus no IPA skin preparation before venesection. There were 194 patients in the study, 93 in the IPA group and 101 controls. There was no statistical difference with respect to complications at the venepuncture site between the two groups.

2-Propanol↗
PubMed1999

Tackling the emerging pandemic of non-communicable diseases in sub-Saharan Africa: the essential NCD health intervention project.

There is evidence that the prevalence of certain non-communicable diseases, such as diabetes and hypertension, is increasing rapidly in parts of sub-Saharan Africa. Others, such as asthma and epilepsy, are known to be common but to be poorly managed. This paper describes a project, funded by the Department for International Development of the British Government, which aims to provide costed and evaluated treatment packages for use at primary health care level, methods and materials for evaluating the quality of non-communicable disease care, and a protocol for the assessment for national opportunities for the prevention of hypertension, heart disease and diabetes. Methods are being developed and piloted in urban and rural Tanzania and Cameroon.

Asthma↗
PubMed1998

Thy-1 is a component common to multiple populations of synaptic vesicles.

Thy-1, a glycosylphosphatidylinositol-linked integral membrane protein of the immunoglobulin superfamily, is a component of both large dense-core and small clear vesicles in PC12 cells. A majority of this protein, formerly recognized only on the plasma membrane of neurons, is localized to regulated secretory vesicles. Thy-1 is also present in synaptic vesicles in rat central nervous system. Experiments on permeabilized PC12 cells demonstrate that antibodies against Thy-1 inhibit the regulated release of neurotransmitter; this inhibition appears to be independent of any effect on the Ca2+ channel. These findings suggest Thy-1 is an integral component of many types of regulated secretory vesicles, and plays an important role in the regulated vesicular release of neurotransmitter at the synapse.

Animals↗
PubMed1998

Heavy metals in antarctic ice from Law Dome: initial results.

Pb, Cd, Cu, and Zn have been measured using ultraclean procedures in eight sections taken from two well-dated ice cores from Law Dome, an independent small size ice cap with high accumulation rate situated in the coastal area of East Antarctica. Seven sections were dated from the 1830s to 1940s and one was dated from three millennia ago. The data show that there are strong seasonal variations in the concentrations of Pb and Cd, with values approximately tow-to fourfold higher in winter than in spring-summer. Evaluation of the contributions from the different sources suggests that contribution from sea salt spray is relatively important, especially for Cd. Contribution from marine biogenic emissions could also be very significant. The importance of marine contributions is consistent with strong intrusions of marine air masses at this coastal site, especially during wintertime.

Aluminum↗
PubMed1998

Speed-dependent motion-sensitive responses in V5: an fMRI study.

This fMRI study examined motion-sensitive responses in human area V5 as a function of stimulus speed. Consistent with electrophysiological findings, we observed optimal responses at intermediate speeds of around 7 degrees/s to 30 degrees/s. The results are consistent with a nonlinear (inverted "U") dependency on speed that was also observed in V3a. V1 activation was observed to decrease linearly as speed increased. This is consistent with the fact that speed-sensitive cells in V1 have been shown to be tuned to much slower speeds than in V5.

Brain↗
PubMed1998

Expression of xenobiotic-metabolizing cytochrome P450s in human pulmonary tissues.

The purpose of the study was to obtain a comprehensive picture of the expression of cytochrome P450s (CYP) in the human lung, broncho-alveolar macrophages (BAM), and peripheral blood lymphocytes. The methods used were reverse transcriptase-polymerase chain reaction (RT-PCR) with gene-specific primers and immunohistochemistry with specific anti-peptide antibodies. In RT-PCR, CYPs 1A1, 2B6/7, 2E1, 2F1, 3A5 and 4B1 were detected in cDNA prepared from whole lung tissue. BAMs expressed CYPs 1B1, 2B6/7, 2C, 2E1, 2F1, 3A5 and 4B1. These tissues lacked CYPs 1A2, 2A6, 2D6, and 3A7. In peripheral blood lymphocytes, only CYP1B1 and CYP2E1 mRNAs were consistently detected. In immunohistochemistry with anti-CYP3A antibodies, epithelial staining of CYP3A5 was observed in 100% of individuals, while only about 20% exhibited CYP3A4 staining. CYP3A5 protein was localized in the bronchial wall, bronchial glands, bronchiolar epithelium, alveolar epithelium, vascular endothelium and alveolar macrophages. The results indicate that several different xenobiotic-metabolizing CYPs are present in the human lung, possibly contributing to in situ activation of pulmonary procarcinogens.

Cytochrome P-450 Enzyme System↗
PubMed1998

Omega-3 polyunsaturated fatty acid levels in the diet and in red blood cell membranes of depressed patients.

BACKGROUND: There is a hypothesis that lack of n-3 polyunsaturated fatty acids (PUFAs) is of aetiological importance in depression. Docosahexaenoic acid, a member of the n-3 PUFA family, is a crucial component of synaptic cell membranes. The aim of this study was to measure RBC membrane fatty acids in a group of depressed patients relative to a well matched healthy control group. METHOD: Red blood cell (RBC) membrane levels, and dietary PUFA intake were measured in 10 depressed patients and 14 matched healthy control subjects. RESULTS: There was a significant depletion of RBC membrane n-3 PUFAs in the depressed subjects which was not due to reduced calorie intake. Severity of depression correlated negatively with RBC membrane levels and with dietary intake of n-3 PUFAs. CONCLUSION: Lower RBC membrane n-3 PUFAs are associated with the severity of depression. LIMITATIONS: Although patient numbers were small, confounding factors were well controlled for and the results were highly significant. Results of the dietary data would tend to be weakened due to the limitations associated with dietary assessment. CLINICAL RELEVANCE: The findings raise the possibility that depressive symptoms may be alleviated by n-3 PUFA supplementation.

Adult↗
PubMed1998

Glutathione-mediated detoxification systems in plants.

Recent work has highlighted the presence of diverse glutathione-dependent enzymes in plants with potential roles in the detoxification of both xenobiotic and endogenous compounds. In particular, studies on glutathione transferases are further characterising their role in xenobiotic metabolism, and also raising intriguing possible roles in endogenous metabolism. The solution of their three-dimensional structures together with studies on their molecular diversity and substrate specificity is providing new insights into the function and classification of these enigmatic enzymes.

Formaldehyde↗