Search PubMed⌕ Search

Biomedical subjects

M Nelson

Publications and source records attributed to M Nelson.

At least 145 records · Page 8Linked to original sources
PubMed2000

The antihypertensive effects of the Jamaican Cho-Cho (Sechium edule).

The experiments reported in this study constitute a preliminary investigation into the possible hypotensive effect of the Jamaican Cho-Cho (Sechium edule). Experiments were conducted in a random and blind fashion on two sub species of Sechium edule. Both the pulp and the peel were examined for hypotensive activity. Water-soluble extracts were prepared from these components of the fruit and injected into anaesthetised rats. Various cardiovascular parameters were measured including heart rate, mean arterial pressure (MAP) and several ECG intervals. We report that all extracts tested produced a fall in blood pressure with little change in ECG intervals. Extract B produced the least change in heart rate with a fall in MAP of approximately 23 mmHg. Changes in heart rate with all extracts appeared to be minimal as an ED25 value could only be determined for extract A, and ED10 values could not be evaluated for extracts C and D. The mechanism(s) by which these extracts produce their hypotensive effects could not be determined in these preliminary experiments. However, it appears not to involve direct effects on cardiac tissue. This conclusion is based on the finding that it took a minimum of 10 to 15 seconds for the hypotensive action to manifest post bolus. Future experiments will be aimed at delineating the mechanism(s) involved in decreasing MAP.

Algorithms↗
PubMed2000

Fruit and vegetable availability among ten European countries: how does it compare with the 'five-a-day' recommendation? DAFNE I and II projects of the European Commission.

Recasting the role of fruit and vegetables (F&V) in the diet, and planning national and international campaigns to enhance their consumption are major public health service objectives. The present study seeks to describe F&V availability patterns in ten European countries and examine compliance with current recommendations. The mean and median F&V availability (g/person per d) was estimated based on household budget survey data retrieved from the Data Food Networking (DAFNE) databank. Low F&V consumers were identified based on WHO international recommendations (minimum combined F&V intake of about 400 g/person per d) and current conservative guidelines of a minimum daily intake of three portions of vegetables and two portions of fruit. Considerable disparities in F&V availability were found among the surveyed European populations. Only in Mediterranean countries did the mean daily population intake clearly exceed combined F&V recommendations. Dietary patterns were positively skewed in all populations studied, on account of the presence of exceptionally high values among segments of the populations. Moreover, the correlation was unexpectedly weak between the proportion of low fruit and low vegetable consumers (Spearman's correlation coefficient +0.18). More than 50% of the households in the surveyed populations are likely to consume less than the recommended daily vegetable intake of three portions, and this applies even to the two Mediterranean populations. The efficiency of F&V promoting strategies may be enhanced if F&V are addressed separately; furthermore, interventions that would specifically focus on vegetables are probably needed.

Europe↗
PubMed2000

Diagnosis and management of male breast enlargement in patients with HIV/AIDS.

There have been several recent reports describing gynecomastia in HIV-1-seropositive patients treated with HAART. However, the etiology of gynecomastia in this setting is far from clear. In this article, we describe the main issues in diagnosis and treatment of gynecomastia and stress the importance of differentiating between "true" gynecomastia and "lipomastia" (pseudogynecomastia), characterized by subcutaneous fat deposition. The importance of switching antiretroviral drugs is also discussed. In addition, newer medical therapies are highlighted.

Gynecomastia↗
PubMed1999

Highly active anti-retroviral therapy (HAART) prolongs time to treatment failure in Kaposi's sarcoma.

OBJECTIVE: To evaluate the impact of highly active antiretroviral therapy (HAART) on Kaposi's sarcoma. DESIGN: Retrospective study of patients who had received systemic or local treatment for AIDS-related Kaposi's sarcoma who subsequently commenced HAART. METHODS: Case note review to determine time to treatment failure for Kaposi's sarcoma before and after starting HAART. Time to treatment failure was calculated from the end of last therapy to the start of the next new treatment for Kaposi's sarcoma. RESULTS: The cohort contained 78 patients. Only 38% had good risk Kaposi's sarcoma (stage T0I0) at presentation. The median time to treatment failure before starting HAART was 0.5 years. Initial HAART therapy was three or more drugs including a protease inhibitor for 38 (49%), three or more drugs without a protease inhibitor for 27 (35%) and a two-drug protease combination for 13 (16%). The median follow-up after starting HAART was 12 months (range, 0.5-52 months) and anti-Kaposi's sarcoma treatment has been required for 24 (31%) patients. The median time to treatment failure for Kaposi's sarcoma from the start of HAART is 1.7 years. This is statistically longer than the time to treatment failure for the same cohort of patients before they started HAART (log rank chi2 = 16.5, P < 0.0001). The serum HIV RNA viral load (VL) at the time of Kaposi's sarcoma progression revealed virological failure of HAART (defined as VL > 5000 copies/ml) in 14 of 24 (58%) and good control (VL < 200 copies/ml) in five of 24 (21%). CONCLUSION: HAART is associated with prolonged time to treatment failure in Kaposi's sarcoma. Progression of Kaposi's sarcoma while on HAART is not necessarily associated with virological failure as determined by rising viral RNA titre.

Adult↗
PubMed1999

Pet travel scheme.

Explore the source record for details and available documents.

Animal Husbandry↗
PubMed1999

The influence of nutritional and metabolic status on progression from asymptomatic HIV infection to AIDS-defining diagnosis.

BACKGROUND: Changes in body weight and lean tissue increase morbidity and mortality during AIDS; however there are few data on the effect of alterations in nutrition and metabolism on disease progression at earlier stages of HIV infection. OBJECTIVES: To assess whether change in weight, lean tissue or skeletal muscle affects progression to AIDS; to assess prospectively the effects of recognized alterations in nutrition and metabolism in asymptomatic HIV-seropositive men on disease progression; and to examine prospectively changes in nutrition and metabolism at AIDS-defining diagnosis. METHODS: A group of 104 asymptomatic HIV-seropositive men were recruited and prospectively examined at 3-monthly intervals between April 1993 and September 1995. Nutritional status and metabolism were examined using indirect calorimetry, dual energy X-ray absorptiometry and urine excretion of simple sugars. Time-fixed and time-dependent Cox's proportional hazard models were fitted to calculate risks of developing a first AIDS diagnosis, weight loss or death. RESULTS: During the study period, 31 subjects had a first AIDS diagnosis of whom 26 were fully assessed. Changes in nutrition and metabolism do not affect disease progression in asymptomatic HIV infection. However, subjects with a reduction in body weight and basal metabolic index tend to have a higher risk of progression to AIDS-defining diagnosis, independent of CD4 count. There is a significant decrease in all body tissue compartments, a decrease in excretion of urinary sugars and significant increase in resting energy expenditure and fat oxidation associated with a first AIDS diagnosis. CONCLUSION: Change in metabolic and nutritional status at the asymptomatic stage of HIV infection does not influence disease progression significantly, although there is a trend suggesting weight loss has an independent effect on outcome. There is a cachectic response to AIDS-defining opportunistic infection or tumour.

Acquired Immunodeficiency Syndrome↗
PubMed1999

Ex vivo expansion and genetic marking of primitive human and baboon hematopoietic cells.

The achievement of positive outcomes in many clinical protocols involving hematopoietic stem cells (HSCs) has been handicapped by the limited numbers of marrow repopulating cells available to actually bring about therapy. This insufficiency has been especially problematic in stem cell transplantation and gene therapy. A number of studies have been initiated to attempt expansion of HSCs, mainly by manipulation of key cytokines in cell suspension cultures. Unfortunately, these expansion methods usually lead to altered properties in the amplified cells, mainly by reducing their self-renewal and multi-lineage differentiative potentials. Here we discuss our ongoing work, utilizing a unique endothelial cell line that supports primitive hematopoiesis, to attempt to generate expansion of primate HSCs that retain their elementary properties. Genetic marking of early hematopoietic cells to facilitate tracking will be mentioned as will the development and employment of assay systems designed to evaluate the long-term functional attributes of the expanded cells.

Animals↗
PubMed1999

Trisomies 8 and 20 characterize a subgroup of benign fibrous lesions arising in both soft tissue and bone.

Trisomy 8 and trisomy 20 are nonrandom aberrations in desmoid tumors. The presence of these trisomies in related benign fibrous lesions of bone has not been previously addressed. In this study, 22 specimens from 19 patients diagnosed with desmoid tumor, desmoplastic fibroma, periosteal desmoid tumor, osteofibrous dysplasia, or fibrous dysplasia were examined by cytogenetic analysis of short-term cultures and bi-color fluorescence in situ hybridization of cytological touch preparations or paraffin-embedded tissue with centromeric probes for chromosomes 8 and 20. Trisomy 8 and trisomy 20 were detected by molecular cytogenetic methodologies in 15 specimens, including 10 primary bone lesions. Traditional cytogenetic analysis revealed trisomy 8 in two cases of osteofibrous dysplasia. Our findings demonstrate that trisomy 8 and trisomy 20 are also nonrandom aberrations in histologically similar, but clinically distinct, benign fibrous lesions of bone.

Adolescent↗
PubMed1999

Use of computerized insole sensor system to evaluate the efficacy of a modified ankle-foot orthosis for redistributing heel pressures.

OBJECTIVE: Evaluation of orthosis purported to decrease pressure on the heel while walking. DESIGN: The Multipodus System is an orthotic device, designed for this purpose, that can be worn with flat or rocker bottom boot. Ten subjects underwent four trials: first, an initial walk wearing their usual shoes, then using the orthosis on the left, with a flat bottom boot, then with a rocker bottom boot, and a final walk. Pressures exerted on the plantar surface of the hindfoot, midfoot, and forefoot were measured electronically and analyzed. SETTING AND PARTICIPANTS: Ten consecutive normal subjects were tested on a conventional tile floor in a gait laboratory. RESULTS: Peak pressures in the initial walk averaged: heel, 9.6 +/- 2.3psi; midfoot, 2.6 +/- 1.7psi; and forefoot, 10.3 +/- 2.6psi. Pressures on the foot were redistributed significantly when the orthosis was used. Heel pressure was reduced significantly compared to the ordinary shoes using both the flat bottom boot (5.0 +/- 1.2psi, a decrease of 48% [p = .0001]) and the rocker bottom boot (4.5 +/- 1.5psi, a decrease of 53% [p = .0001]). Pressure was increased at the midfoot with both the flat bottom boot (6.6 +/- 3.2psi, an increase of 61% [p = .0001]) and the rocker bottom boot (6.8 +/- 2.9psi, an increase of 62% [p = .0001]). Pressures at the forefoot decreased 19% (8.3psi) with the flat bottom boot and 32% (7.0psi; p = .0003) with the rocker bottom boot. CONCLUSIONS: Redistribution of pressure on the foot with orthosis is characterized by reduction at the hindfoot and forefoot and increase at the midfoot with both the flat and rocker bottom boots, thereby promoting healing of calcaneal and forefoot ulcers. The integrity of the midfoot, however, must not be compromised.

Adult↗
PubMed1999

Treatment outcome in presumed and confirmed AIDS-related primary cerebral lymphoma.

A retrospective analysis identified 38 HIV seropositive patients with a diagnosis of presumed (n = 26) or confirmed (n = 12) primary cerebral lymphoma (PCNSL). All patients had failed to respond to empirical antitoxoplasma therapy and the clinical diagnosis of PCNSL was confirmed by brain biopsy (n = 4), cerebrospinal fluid (CSF) examination for Epstein-Barr virus (EBV) by PCR (n = 7) or postmortem examination (n = 1). There was no difference in the age, performance status, CD4 counts, antiretroviral usage or interval since first HIV serodiagnosis between patients with presumed or confirmed PCNSL. 16 patients received either radiotherapy (n = 14) or chemotherapy (n = 2). Patients with confirmed or presumptive PCNSL were equally likely to receive treatment. The median overall survival, which was measured from the end of unsuccessful antitoxoplasma therapy, was 1.2 months for the whole cohort. There was no difference in overall survival between patients with presumptive (median 0.8 months) and confirmed (median 1.3 months) PCNSL (logrank P = 0.69). This suggests that there may be little value in positively diagnosing PCNSL in the current diagnostic algorithm. Recent improvements in outcome have been reported with systemic chemotherapy in HIV-PCNSL and may influence the need for earlier definitive diagnosis in the future.

Adult↗
PubMed1999

A comparison of an A1 adenosine receptor agonist (CVT-510) with diltiazem for slowing of AV nodal conduction in guinea-pig.

1. The purpose of this study was to compare the pharmacological properties (i.e. the AV nodal depressant, vasodilator, and inotropic effects) of two AV nodal blocking agents belonging to different drug classes; a novel A1 adenosine receptor (A1 receptor) agonist, N-(3(R)-tetrahydrofuranyl)-6-aminopurine riboside (CVT-510), and the prototypical calcium channel blocker diltiazem. 2. In the atrial-paced isolated heart, CVT-510 was approximately 5 fold more potent to prolong the stimulus-to-His bundle (S-H interval), a measure of slowing AV nodal conduction (EC50 = 41 nM) than to increase coronary conductance (EC50 = 200 nM). At concentrations of CVT-510 (40 nM) and diltiazem (1 microM) that caused equal prolongation of S-H interval (approximately 10 ms), diltiazem, but not CVT-510, significantly reduced left ventricular developed pressure (LVP) and markedly increased coronary conductance. CVT-510 shortened atrial (EC50 = 73 nM) but not the ventricular monophasic action potentials (MAP). 3. In atrial-paced anaesthetized guinea-pigs, intravenous infusions of CVT-510 and diltiazem caused nearly equal prolongations of P-R interval. However, diltiazem, but not CVT-510, significantly reduced mean arterial blood pressure. 4. Both CVT-510 and diltiazem prolonged S-H interval, i.e., slowed AV nodal conduction. However, the A1 receptor-selective agonist CVT-510 did so without causing the negative inotropic, vasodilator, and hypotensive effects associated with diltiazem. Because CVT-510 did not affect the ventricular action potential, it is unlikely that this agonist will have a proarrythmic action in ventricular myocardium.

Action Potentials↗
PubMed1999

Household budget survey nutritional data in relation to mortality from coronary heart disease, colorectal cancer and female breast cancer in European countries. DAFNE I and II projects of the European Commission. Data Food Networking.

OBJECTIVE: We have undertaken a study to examine whether Household Budget Survey (HBS)-derived nutritional patterns are related to mortality from diseases with strong nutritional components, namely coronary heart disease, colorectal cancer and cancer of the female breast. DESIGN: Ecological correlation study. In the context of the Data Food Networking projects of the European Union, raw data from the national HBS of 10 European countries were provided. For each of the 10 participating countries, daily food availability per capita around 1990 was calculated. Individual foods were aggregated into 12 major food groups that were linked with the diseases under consideration. Mortality data were available from a World Health Organisation database. We have used a composite score to summarise the postulated influence of diet. SETTING: Ten European countries circa 1990. RESULTS: The correlation coefficients between the composite score and the age-adjusted mortality from each of the studied diseases were: + 0.51 (P approximately 0.14) for colorectal cancer; +0.72 (P approximately 0.02) for female breast cancer; and +0.60 (P approximately 0.07) for coronary heart disease, after adjustment for tobacco smoking. CONCLUSIONS: We conclude that dietary information from HBS is sufficiently reliable to reveal correlations with mortality rates from chronic diseases with fairly strong nutritional roots. HBS data could be used, with little cost, for monitoring secular trends in dietary patterns with a view to their health implications.

Animals↗
PubMed1999

An overview of the use of flow cytometry in the analysis of mixed red cell populations.

This paper reviews the application of flow cytometric techniques to the analysis and quantitation of mixed red cell populations. Such mixtures may arise in a variety of ways, for example: through transplacental hemorrhage during pregnancy or upon delivery; through iatrogenic procedures such as blood transfusion, bone marrow or peripheral blood stem cell transplantation; or through disease, when a loss of surface antigen expression may occur due to the expansion of abnormal progenitors lacking the appropriate gene or lacking the ability to translate the product of the gene. Flow cytometry can offer a simple and accurate means of identifying and quantitating mixed red cell populations through detection of antigens specific for either donor or recipient, and in many cases it is possible to distinguish homo- or heterozygous expression of a common antigen. Internal antigens may be accessed after fixation and permeabilisation of the red cells. These latter techniques are relatively new and expand the spectrum of antigenic differences available for the identification of individual species in mixed populations.

Antigens↗
PubMed1999

Intraoperative angiography in the management of pediatric vascular disorders.

We reviewed our experience with intraoperative angiography in the management of 7 cerebral aneurysms and 15 arteriovenous malformations (AVMs) in children over the past 5 years. The patients ranged from 4 months to 18 years of age with a mean age of 9 years. In 4 of the 22 cases, angiography provided information that led to changes during surgery. In 3 cases, the intraoperative angiogram revealed residual AVMs that were then completely resected. In 1 patient with an anterior circulation aneurysm, intraoperative studies revealed findings which resulted in clip repositioning. Intraoperative angiography added a mean of 43 (+/-19) min to the operative time, with a mode of 40 minutes. There was 1 complication, a groin hematoma that readily resolved. Intraoperative angiography prolongs to operative course; however, it is a useful adjunct to the management of vascular disorders in children. We now routinely use and recommend intraoperative angiography to assist with the surgical management of vascular malformations in children.

Adolescent↗