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Biomedical subjects

A Scott

Publications and source records attributed to A Scott.

At least 343 records · Page 19Linked to original sources
PubMedDate not supplied

Analysing the effect of competition on general practitioners' behaviour using a multilevel modelling framework.

This paper examines the effect of competition on the behaviour of Australian general practitioners. The paper represents a considerable improvement on the methods of previous studies by using a random effects probit model in a multilevel modelling framework to obtain a more robust estimate of the effect of GP density, by including data on GP and practice characteristics and by using data with the actual GP consultation as the unit of observation which are disaggregated by medical condition. This latter characteristic enables us to test the hypothesis that the effect of competition varies across medical conditions. The main hypothesis tested is that GPs in areas of high competition are more likely to recommend a follow-up consultation compared to GPs in areas of low competition. The results suggest that the density of GPs influences the decision to follow up for one out of the four medical conditions analysed. However, there are other issues to be resolved before such results can be confidently interpreted as evidence of the effect of competition and as evidence of supplier-induced demand.

Adolescent↗
PubMedDate not supplied

Investigating hospital efficiency in the new NHS: the role of the translog cost function.

The reforms to the United Kingdom's National Health Service (NHS) of recent years have greatly increased the role of economic incentives in the hospital sector. Hospitals now have to compete for the business of GP and health authority purchasers and are assumed to have an incentive to minimise costs. This makes the analysis of cost functions much more relevant than has previously been the case. The objective of this paper is to assess the potential usefulness of the translog cost function applied in the NHS internal market. Three main issues are identified that limit the role of this type of cost function in the internal market: the adequacy of the econometric model (including data quality); the assumptions underlying the model, and; the interpretation of economies of scale, marginal costs and economies of scope that can be derived from such a cost function. It is concluded that at present the application of translog cost function analysis in the NHS is of limited usefulness, but that it does indicate areas for further methodological research.

Economic Competition↗
PubMedDate not supplied

131I isotope placentography: simple counting equipment in obstetric practice.

Simple counting equipment and radioiodinated human serum albumin (131IHSA) were used to perform placental localization on 48 pregnant women with antepartum hemorrhage. The level of diagnostic accuracy of 85% compares favorably with more expensive methods. The false-negative diagnosis rate for the whole group was 4% and the false-positive diagnosis rate was 8%. The authors recommend this method of isotope placentography for developing countries because the cost of the equipment, including maintenance, and the isotopes is relatively small, and the radiation hazards are negligible.

Adult↗
PubMedDate not supplied

A comparison of pollutant biomarker responses with transcriptional responses in European flounders (Platicthys flesus) subjected to estuarine pollution.

European flounders from two UK estuaries with different contaminant profiles were sampled and analysed for impacts of PAHs, heavy metals and estrogenic compounds by currently adopted measurement procedures used in statutory monitoring programs. These showed that fish from the polluted Tyne estuary had responded to all three classes of pollutants with elevations in hepatic EROD, MT and plasma VTG and that there was considerable interanimal variation in the magnitude of the response. Analysis of PAH metabolites in bile showed recent uptake of low molecular weight PAHs. The pollutant response was also apparent when hepatic levels of cytochrome P450 1A (CYP1A), metallothionein (MT) and vitellogenin (VTG) mRNAs were quantified by real time PCR. Whilst there did not appear to be a direct correlation between levels of gene transcripts and their protein products on an individual basis, these results demonstrate that measurements of mRNA levels of specific genes, or their protein products both demonstrate induction in polluted environments and are thus valid measures in biomonitoring studies. Procedurally, the use of the single generic technology of Q-PCR was much simpler and is worth pursuing in future studies.

Animals↗
PubMedDate not supplied

Production of neutrons from interactions of GCR-like particles.

In order to help assess the risk to astronauts due to the long-term exposure to the natural radiation environment in space, an understanding of how the primary radiation field is changed when passing through shielding and tissue materials must be obtained. One important aspect of the change in the primary radiation field after passing through shielding materials is the production of secondary particles from the breakup of the primary. Neutrons are an important component of the secondary particle field due to their relatively high biological weighting factors, and due to their relative abundance, especially behind thick shielding scenarios. Because of the complexity of the problem, the estimation of the risk from exposure to the secondary neutron field must be handled using calculational techniques. However, those calculations will need an extensive set of neutron cross section and thicktarget neutron yield data in order to make an accurate assessment of the risk. In this paper we briefly survey the existing neutron-production data sets that are applicable to the space radiation transport problem, and we point out how neutron production from protons is different than neutron production from heavy ions. We also make comparisons of one the heavy-ion data sets with Boltzmann-Uehling-Uhlenbeck (BUU) calculations.

Aerospace Medicine↗
PubMedDate not supplied

Abrogation of IL-3 and IL-2 dependence by recombinant murine retroviruses expressing v-myc oncogenes.

Several oncogenes are thought to cause transformation by affecting the signal transmission pathway of growth factors. One example is the induction of c-myc, the cellular homologue of the avian transforming oncogene v-myc, by platelet-derived growth factor (PDGF) among a set of genes associated with competence induction in fibroblasts. Another of the competence genes, r-fos, has been shown to be related to v-fos, the transforming gene of the FBJ sarcoma virus. In addition, PDGF induces c-fos, the cellular homologue of v-fos. The importance of c-myc induction is suggested by the observation that c-myc, under the control of a glucocorticoid regulator, can partially relieve the requirement of fibroblasts for PDGF. We have examined the effects of oncogenes on haematopoietic/lymphoid cell differentiation, immortalization and factor dependence for growth. Here we report the effects of recombinant murine retroviruses capable of expressing the avian v-myc. With interleukin-3 (IL-3)- or interleukin-2 (IL-2)-dependent cells, the viruses abrogated the requirement for growth factors and suppressed c-myc expression.

Animals↗
PubMedDate not supplied

Transmission through the female line of a mechanism constraining human fetal growth.

Cross-breeding experiments between large and small strains of mammals have shown the powerful influence of the maternal organism on the control of fetal growth. The prepotency of a maternal regulator has also been demonstrated in humans. Our earlier studies indicated that this regulator acts by means of constraint; there is no equivalent accelerating mechanism. Data on 1092 siblings and 5207 paternal and maternal relatives of 986 probands show different patterns of birthweight among families ascertained, respectively, through very large and very small babies. When constraint is relaxed the Mendelian laws of inheritance are clearly followed. At the lower extreme there is evidence for the transmission of constraint through the female line only. This could be due to the maternal genotype, but our data suggest that a non-Mendelian path might also be involved. Such a process would be adaptive, facilitating fairly fast changes in fetal growth rate as the conditions under which a population lives deteriorate or improve.

Analysis of Variance↗
PubMedDate not supplied

Constrained and unconstrained fetal growth: associations with some biological and pathological factors.

Data are presented on the birthweights of 1092 siblings and 5207 maternal and paternal relatives of 986 probands. Previous analyses had demonstrated the potency of a maternal regulator constraining fetal growth. Different patterns of birthweights were found in families ascertained, respectively, through very large and very small babies (Ounsted, Scott and Ounsted 1986). When the data were reanalyzed in respect of other biological and pathological factors affecting fetal growth rate the following findings emerged: (1) When pathological factors were associated with the proband pregnancy the typical patterns of pedigree birthweights were not so clearly manifest; (2) general associations were found between the mothers' own birthweights and their size as adults; (3) low maternal birthweight was the biological factor showing the highest risk associated with small babies. When the babies were large the risks associated with high maternal adult weight and parity were similar to those associated with high birthweight. Paternal factors also made a contribution to fast fetal growth rate when pathological factors were absent. These findings confirm our hypothesis that at the lower extreme of fetal growth rate maternal constraint is pre-potent. At the upper extreme, relaxation of constraint allows other biological factors to take up more of the variance.

Adult↗
PubMedDate not supplied

In vitro generation of Epstein-Barr virus-specific cytotoxic T cells in patients receiving haplo-identical allogeneic stem cell transplantation.

Use of a partially mismatched related donor (PMRD) is an option for patients who require allogeneic transplantation but do not have a matched sibling or unrelated donor. Epstein-Barr virus (EBV)-induced lymphoma is a major cause of mortality after PMRD transplantation. In this study, we present a clinical grade culture system for donor-derived EBV-specific cytotoxic T cells (CTLs) that do not recognize haplo-identical recipient cells. The EBV-specific CTLs were tested for cytolytic specificity and other functional properties, including ability to transgress into tissues, propensity for apoptosis, degree of clonality, stability of dominant T-cell clones, and Tc and Th phenotypes. The EBV-specific CTLs were routinely expanded to greater than 80 x 10(6) over a period of 5 weeks, which is sufficient for clinical application. A CD8+ phenotype predominated, and the CTLs were highly specific for donor lymphoblastoid cell lines (LCLs) without killing of recipient targets or K562. Vbeta spectratyping showed an oligoclonal population that was stable on prolonged culture. The EBV-specific CTLs were activated (D-related human leukocyte antigen [HLA-DR+], L-selectin+/-) and of memory phenotype (CD45RO+). Expression of the integrin VLA-4 suggested that these CTLs could adhere to endothelium and migrate into tissues. The Bcl-2 message was upregulated, which may protect the CTLs from the apoptosis. The first demonstration of overexpression of bcl-2 in human memory CTLs. In addition, we show that lymphoblastoid cell lines used to generate CTLs are readily genetically modified with recombinant lentivirus, indicating that genetically engineered antigen presentation is feasible.

Adolescent↗
PubMedDate not supplied

Increased incidence of anxiety and depressive disorders in persons with organic solvent exposure.

OBJECTIVE: The purpose of this study was to determine whether the prevalence of current and past DSM-IV axis I psychiatric disorders is higher among persons with a history of exposure to organic solvents than among a demographically similar group of nonexposed control subjects. METHODS: Thirty-eight solvent-exposed subjects and 39 nonexposed healthy control subjects were evaluated for axis I disorder with the Structured Clinical Interview for DSM-IV. RESULTS: A significantly higher number of solvent-exposed subjects (71%) met criteria for current DSM-IV axis I disorder in comparison with control subjects (10%). The most prevalent diagnosis in exposed subjects was within the anxiety and mood clusters, with a high percentage (36%) of exposed subjects meeting criteria for a dual diagnosis of mood and anxiety disorder. There were no differences between the groups in past psychiatric disorders or current or past substance abuse or dependence. CONCLUSIONS: The rates of past psychiatric disorders among solvent-exposed subjects are similar to those among normal control subjects, but the prevalence of current DSM-IV axis I psychiatric disorders is significantly higher among exposed subjects than among control subjects.

Adult↗
PubMedDate not supplied

The effect of high frequency oscillatory ventilation on extravascular lung water in the rabbit.

High frequency ventilation (HFV) systems have the theoretical advantage of producing less barotrauma and lung damage because of the associated smaller oscillations in alveolar pressure compared to conventional ventilators. An index of lung damage is an increase in extravascular lung water but previous studies using HFV have produced conflicting results. Lung wet-to-dry ratio, extravascular lung water and blood mass were measured in 30 rabbits divided into three groups (n = 10); spontaneously breathing (SV), conventional positive pressure ventilation (CV) and high frequency oscillatory ventilation (HFV). HFV maintained normal blood gases and produced a significant reduction in the wet-to-dry weight ratio compared to SV and CV (P less than 0.05). Extravascular lung water and blood mass were significantly reduced in HFV compared to SV (P less than 0.05). It is concluded that the system of HFV used in this study has clinical potential in the treatment of lung injury.

Animals↗
PubMedDate not supplied

Nutritional screening: an audit.

Despite much guidance, patients in hospital are still not eating properly. This article discusses the development of a Nutritional Screening Tool (NST) and an audit of the use of the tool with nutritional supplements.

Humans↗
PubMedDate not supplied

Ciloxan for the management of corneal ulcers.

Bacterial keratitis (corneal ulcer) is a sight-threatening condition if not treated with the appropriate anti-infective agent. Treatment needs to be initiated with a broad-spectrum agent deemed to be most appropriate until culture results are obtained. If the suspected pathogen is staphylococci, streptococci, or Pseudomonas, Ciloxin is a new generation anti-infective agent considered highly effective against these pathogens.

Adult↗