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Biomedical subjects

A Taylor

Publications and source records attributed to A Taylor.

At least 361 records · Page 20Linked to original sources
PubMed1996

First steps toward harmonisation of European EQAS in occupational and environmental laboratory medicine: from Dublin to Rome.

Laboratories performing analyses in the field of occupational and environmental medicine (OELM) must provide reliable results for an increasing number of analytes related to exposure to chemicals. Participation in external quality assessment schemes (EQAS) allows laboratories to assess their performance and is regarded as a pre-requisite for accreditation from appropriate national and supranational bodies. Within the framework of the European Union, harmonisation of procedures for evaluation of laboratory performance in EQAS is desirable, in order to achieve a similar degree of excellence within Europe. Collaboration among different countries would also be profitable to compare experiences, develop new schemes, covering a wider range of analytes, and to devise common research on specific problems. We report on initiatives developed to meet this objective, in collaboration with the Standards, Measurements & Testing (SM&T) programme of the European Commission (EC), Directorate General XII. Meetings were held in Dublin and Rome which allowed experience among European EQAS organisers in OELM to be shared. Discussion focused on the identification of common needs and areas where collaborative work could be carried out.

Environmental Health↗
PubMed1996

The Guildford trace elements external quality assessment scheme.

An international external quality assessment scheme for trace elements in biological fluids is described. Programmes for aluminium, copper, zinc, selenium, gold, lead, cadmium and mercury in serum, blood, urine, dialysis fluids and water are included with others under development. Preparation of reports is described and assessments of performance based on proximity to assigned values, differences in results between duplicate measurements and recovery of added analyte are given. Performance standards have been introduced to stimulate improvements in the quality of results.

Dialysis↗
PubMed1996

Prospects of harmonisation of European external quality assessment schemes in occupational and environmental laboratory medicine.

Since 1979, twelve external quality assessment schemes (EQAS) in occupational and environmental laboratory medicine (OELM) have been developed in nine European countries. These schemes cover a broad range of analytes and matrices and have developed differing procedures for the evaluation of laboratories' performances. Collaboration among EQAS in OELM and harmonisation of methods for evaluation of laboratory performance would be advantageous to cope with the demand for assessment of quality of analytical results for an increasing number of analytes and the need to guarantee comparability and consistency of conclusions on health and regulatory issues in different countries and at an international level. This paper compares the different features of the existing EQAS, to highlight critical points for further discussions, and to make some suggestions for possible further collaboration.

Environmental Medicine↗
PubMed1996

Report of the Radionuclides in Nephrourology Committee on renal clearance.

The need for simple and accurate methods to measure renal function is self-evident. This need increases as techniques for intervention become available. The demand for evaluation of individual kidney function has increased with its role in the diagnosis and follow-up of unilateral renal disease and in decision making for conservative or surgical treatment based on residual renal function. The role of nuclear medicine in this area has been inhibited by confusion about conflicting methodologies. This report is meant to provide guidance to those centers that would like to initiate clearance procedures but have difficulty in choosing appropriate methodology.

Glomerular Filtration Rate↗
PubMed1996

Audit on the use of prophylactic parenteral antimicrobial agents and the use of co-amoxiclav and metronidazole.

UNLABELLED: Following the recommendations of a previous audit, specific objectives were chosen for reaudit. The aim was to measure the adherence to agreed protocols for the use of prophylactic antimicrobial agents; including the use of the once only part of the Kardex and to measure the adherence to protocols for the use of parenteral co-amoxiclav and metronidazole. The audit was conducted in the same hospital as the original study. Data was collected for one month on all patients receiving prophylactic antimicrobial agents, parenteral co-amoxiclav or metronidazole. A microbiologist assessed the compliance to the agreed written protocols, which had been distributed and explained to each resident. One hundred and eighty-eight patients received 226 antimicrobial courses (649 doses). Seventy-two per cent of courses were considered appropriate compared with 65% in 1993. The criteria for this audit only allowed one cephalosporin choice per directorate and accounted for the inappropriateness of choice to be 19% compared with 12% in 1993. This was confined to one directorate and an overall improvement of 79% would have been achieved if any cephalosporin could be chosen as 1993. Eighty-two per cent of doses were considered appropriate if written in the once only part of the Kardex or the anaesthetic sheet compared with 51% of those written in the general part. Only nine per cent of courses were too long compared with 16% in 1993. Fifty seven patients were given 125 days of co-amoxiclav, 94 days for treatment and 31 days for prophylaxis. Co-amoxiclav use overall was 33% less than 1993 with an improvement of appropriateness from 30% to 68%. CONCLUSIONS: An overall improvement in the appropriateness of prophylactic antibiotic use was achieved by the implementation of agreed protocols. An automatic stopping system reduced the continuation of prophylaxis.

Amoxicillin↗
PubMed1995

Mercury in environmental and biological samples from a gold mining area in the Amazon region of Brazil.

A massive increase in gold mining in the Amazon region of Brazil has led to an enormous discharge of metallic mercury into the aquatic ecosystem. To investigate the dispersion, total and inorganic mercury concentrations were measured in water, fish and animal tissues, and in blood, urine and hair from members of the local populations. Mercury concentrations in river water, sediments and fish were high compared with those of non-contaminated areas. Cattle and pigs kept in the area and with access to the contaminated rivers had concentrations of mercury of 0.1-1.28 micrograms/g and 11.7-15.7 micrograms/l in hair and blood, respectively. These results are approximately twice those measured in specimens from control animals. Mean mercury concentrations in blood, urine and hair of residents were increased at 11.4 micrograms/l, 22.8 micrograms/l and 4.3 micrograms/g, respectively, and the urine mercury of workers from the gold mining sites were up to 155 micrograms/l. The results demonstrate widespread contamination of the environment by mercury with transfer of the metal to fish and animals used for food, and into the inhabitants of the region. Further investigations for possible adverse health effects need to be undertaken.

Animals↗
PubMed1995

Finance. PAYE day.

Explore the source record for details and available documents.

Financial Management↗
PubMed1995

Oxidative stress and recovery from oxidative stress are associated with altered ubiquitin conjugating and proteolytic activities in bovine lens epithelial cells.

Roles for ubiquitin (an 8.5 kDa polypeptide) involve its conjugation to proteins as a signal to initiate degradation and as a stress protein. We investigated ubiquitin conjugation and ubiquitin-dependent proteolytic activities in cultured bovine lens epithelial cells (BLECs) upon oxidative challenge. A 44% decrease in intracellular glutathione confirmed oxidative stress upon incubation with 1 mM H2O2. After 30 min incubation, endogenous high-molecular-mass ubiquitin conjugates decreased 73%, and intracellular proteolysis decreased about 50%. In the supernatants of the oxidatively treated BLECs, the ability to form high-molecular-mass ubiquitin conjugates with exogenous 125I-labelled ubiquitin decreased 28%, and ATP-dependent degradation of oxidized alpha-crystallin decreased 36%. When the H2O2-treated BLECs were allowed to recover for 60 min, intracellular proteolysis returned to the level of control cells. There was also a subsequent transient enhancement of intracellular proteolysis and a simultaneous recovery of endogenous high-molecular-mass ubiquitin conjugates. In parallel cell-free experiments, conjugating activity with exogenous 125I-labelled ubiquitin and ATP-dependent degradation of oxidized alpha-crystallin increased 35% and 72% respectively compared with non-oxidatively treated BLECs. ATP-independent proteolysis showed little response to exposure or removal of H2O2. These results indicate that (1) the rate of intracellular proteolysis in BLECs is associated with the level of endogenous high-molecular-mass ubiquitin conjugates and (2) oxidative stress may inactivate the ubiquitin conjugation activity with coordinate depression of proteolytic capability. Enhancement in ubiquitin conjugation and proteolytic activities during recovery from oxidative stress may be important in removal of damaged proteins and restoration of normal function of BLECs. The inactivation of ubiquitin-dependent proteolysis by oxidation may be involved in the accumulation of altered proteins and other adverse sequelae in the oxidatively challenged aging lens.

Adenosine Triphosphate↗
PubMed1995

Dietary calorie restriction in the Emory mouse: effects on lifespan, eye lens cataract prevalence and progression, levels of ascorbate, glutathione, glucose, and glycohemoglobin, tail collagen breaktime, DNA and RNA oxidation, skin integrity, fecundity, and cancer.

The Emory mouse is the best model for age-related cataract. In this work we compare the effects of feeding a control diet (C) with a diet restricted (R) by 40% relative to C animals. In the R animals, median lifespan was extended by 40%. The proportion of R mice with advanced cataract was lower than C mice as early as 5 months of age. The mean grade of cataract was lower in R animals, beginning at 11 months and continuing until the end of the study. Ascorbate levels in R plasma and liver were 41-56% of C animals. There was no difference between diet groups with respect to lens ascorbate. Aging was associated with a decrease in ascorbate in lenses and kidneys in C and R mice. By 22 months, R animals had 48% higher liver glutathione levels than C mice. Liver glutathione levels were maximal at 12 months. Plasma glucose levels were > 27% lower in R animals at 6.5 and 22 months, and there was a 14% increase in glucose levels upon aging for both diet groups. In R mice, glycohemoglobin levels were 51% lower and tail collagen breaktime was decreased by 40%, even in younger animals. Collagen breaktime increased > 360% upon aging for both diet groups. Rates of production of urinary oxo8dG and oxo8G were higher in R animals compared with C animals, and increased upon aging. C animals exhibited more cancer and dermatological lesions, but less tail tip necrosis and inflamed genitals than R mice. These data allow evaluation of several theories of aging.

Animals↗
PubMed1995

Outbreak of HIV infection in a Scottish prison.

OBJECTIVE--To investigate the possible spread of HIV infection and its route of transmission among prison inmates. DESIGN--In response to an outbreak of acute clinical hepatitis B and two seroconversions to HIV infection, counselling and testing for HIV were offered to all inmates over a two week period in July 1993. Information was sought about drug injecting, sexual behaviour, and previous HIV testing. SETTING--HM Prison Glenochil in Scotland. SUBJECTS--Adult male prisoners. MAIN OUTCOME MEASURES--Uptake of HIV counselling and testing; occurrence and mode of HIV transmission within the prison. RESULTS--Of a total 378 inmates, 227 (60%) were counselled and 162 (43%) tested for HIV. Twelve (7%) of those tested were positive for antibody to HIV. One third (76) of those counselled had injected drugs at some time, of whom 33 (43%) had injected in Glenochil; all 12 seropositive men belonged to this latter group. Thirty two of these 33 had shared needles and syringes in the prison. A further two inmates who injected in the prison were diagnosed as positive for HIV two months previously. Evidence based on sequential results and time of entry into prison indicated that eight transmissions definitely occurred within prison in the first half of 1993. CONCLUSION--This is the first report of an outbreak of HIV infection occurring within a prison. Restricted access to injecting equipment resulted in random sharing and placed injectors at high risk of becoming infected with HIV. Measures to prevent further spread of infection among prison injectors are urgently required.

Adult↗
PubMed1995

Can we target smoking groups more effectively? A study of male and female heavy smokers.

BACKGROUND: In recent years a number of studies have examined subgroups within the smoking population. These studies have provided information which facilitate improved targeting of programs and interventions to help smokers quit. Despite this there have been few population studies which have described male and female heavy smokers and compared their characteristics. METHODS: We used representative population data on 789 smokers to examine differences between light and heavy smokers of each gender and between male and female heavy smokers directly. RESULTS: Of those who smoked, 35% of males and 24% of females were classified as heavy smokers and represent a large target group within the smoking population. Whereas a light smoker was characterized as smoking a median of 12.5 cigarettes per day, the heavy smoker smoked a median of 32 cigarettes per day. Univariate comparison of heavy smokers and light smokers showed a number of statistically significant differences according to demographics, in smoking behaviors and knowledge, in beliefs about smoking, in smoking characteristics, and in other health indicators. Because of interactions between gender and work/leisure day smoking variation, separate logistic regression models based on gender were fitted to the data. Again, compared with light smokers, several significant differences emerged for both heavy female and heavy male smokers under the headings mentioned above. Further logistic regression analyses showed differences between male and female heavy smokers when compared directly. CONCLUSIONS: The smoking population of South Australia is not homogeneous and this segmentation study has shown the need for varying approaches to different segments when developing intervention programs.

Adult↗
PubMed1995

Nephrocalcinosis in X-linked hypophosphatemia: effect of treatment versus disease.

While the literature has suggested that vitamin D and phosphate therapy benefits children, and possibly adults, with X-linked hypophosphatemia (XLH), there have been increasing reports of nephrocalcinosis by renal ultrasound examination in treated patients. Although it has been assumed that nephrocalcinosis is the result of treatment, there has been no systematic comparison of treated and untreated XLH patients with long-term follow-up. Therefore, we studied 10 adults and 4 children by renal ultrasound examination with no history of medical therapy and 10 adults and 8 children with a history of medical therapy. None of the untreated patients had nephrocalcinosis; 5 treated adults and 5 treated children had nephrocalcinosis. In 3 of 4 treated children, serial renal ultrasounds did not show progression of the nephrocalcinosis. One patient progressed from baseline to year 1 only. Comparisons of means between treated patients without and with nephrocalcinosis showed statistically significant differences for urine calcium/creatinine ratios and urine phosphorus/creatinine ratios, differences not seen between untreated patients and treated patients without nephrocalcinosis. Phosphate dose, but not vitamin D dose, was statistically significantly different between the two treated groups. Our studies point to a convincing role for the association between nephrocalcinosis, as diagnosed by renal ultrasound examination, and medical therapy.

Child↗
PubMed1995

High-field MRS studies in brain slices.

We are applying multi-nuclear high-field (500 MHz) MR spectroscopy of metabolising whole tissue preparations of the mammalian brain to studies on individual components of convulsions, which include prolonged depolarization, metabolic deprivation, and the effects of excitotoxins. The responses of glial cells and neurones can be partially distinguished by following labelling patterns of metabolic intermediates from 13C-labelled glucose or acetate (which enters only glial cells). This approach clearly confirmed our earlier indications that the metabolic response to depolarization (40 mM extracellular K+) occurs essentially in glial cells. Some evidence for metabolic shuttling between glia and neurones was obtained from the changes in C3/C4 ratios of glutamate and glutamine, and the C2/C3 of GABA. Mechanisms for metabolic support of neurones by glia may be of importance in neuronal protection under such metabolic stress as occurs in epilepsy. Changes in free intracellular divalent cations ([Ca2+]i and [Zn2+]i) were monitored using the 19F-MRS indicator, 5FBAPTA. Large increases in [Ca2+]i and decreases in PCr were produced by excitotoxins (glutamate and NMDA), depolarization or ischemia, but intracellular Zn2+ appeared only after exposure to the excitotoxins. The NMDA receptor blocker, MK801, removed all of the responses to NMDA, but only prevented the appearance of Zn2+ observed with glutamate. These results indicate that the damage caused to neurones by such insults as convulsions is not due simply to the presence of excessive excitotoxic glutamate.

Animals↗
PubMed1995

Degradation of differentially oxidized alpha-crystallins in bovine lens epithelial cells.

There is a growing consensus that altered proteins are more susceptible to degradation than native proteins. The enhancement of degradation of damaged proteins may be of significance since it prevents the accumulation of damaged proteins in cells. Several proteolytic pathways have been discovered in the lens. These include ATP-independent, ATP-dependent and ATP/ubiquitin-dependent proteolytic pathways. However, the extent of involvement of these proteolytic pathways in degradation of damaged proteins is not well described. alpha-Crystallin was oxidized by exposure to 0.03-3.2 mol.OH (mol protein)-1. Modifications to the oxidized alpha-crystallin and proteolytic susceptibility of the oxidized alpha-crystallin were studied. Exposure to > 0.32 mol.OH per mole of subunit produced aggregates and fragments of alpha-crystallin. Changes in isoelectric points of the proteins were observed after exposure to 0.64 mol.OH (mol protein)-1. The extent of loss of tryptophan and sulfhydryl groups was related to the level of .OH-exposure. Carbonyl content increased progressively with increasing oxidation. When incubated with a supernatant of bovine lens epithelial cells, the .OH-modified proteins were proteolytically degraded up to three times faster than untreated alpha-crystallin. ATP stimulated the degradation of native alpha-crystallin and alpha-crystallin which was exposed to 1.6 mol.OH (mol subunit protein)-1 (alpha 1.6). Sixty-seven per cent and 100% of the ATP-dependent degradation of native alpha-crystallin and alpha 1.6 was ubiquitin-dependent, respectively. The data indicate that alpha-crystallins oxidized by .OH are recognized and degraded rapidly by cytoplasmic proteolytic systems in bovine lens epithelial cells. Both ATP-independent and ATP/ubiquitin-dependent proteolytic pathways are involved in the degradation of native and oxidized alpha-crystallin.

Animals↗