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Biomedical subjects

R R West

Publications and source records attributed to R R West.

At least 37 records · Page 2Linked to original sources
PubMed1996

Evaluation of a rapid diagnostic test for bacterial vaginosis.

OBJECTIVE: To evaluate a new rapid diagnostic test for bacterial vaginosis. DESIGN: Comparison of a new biochemical diamine test with low technology tests and microbiological culture. SETTING: General practice, family planning clinic. MAIN OUTCOME MEASURES: Comparison of the new diamine test with microbiological culture for Gardnerella vaginalis, with clue cells, and with the amine test. RESULTS: Two hundred and twenty-nine vaginal swabs were assayed quantitatively by the new diamine test. When compared with microbiological culture of Gardnerella vaginalis, the sensitivities and specificities were 86% and 81%, respectively. When compared with clue cell findings, the sensitivities and specificities were 97% and 83%, respectively. In the third comparison with the amine test the sensitivity was 94% and the specificity was 84%. Since microbiological diagnosis of organisms related to bacterial vaginosis is difficult, the new test and existing sideroom tests may be more sensitive to the condition and the true frequency of false positives may be less than the specificity in this study suggests. CONCLUSIONS: The new diamine test is accurate, sensitive and specific, and provides the basis for the rapid diagnosis of bacterial vaginosis. Such a test is needed if bacterial vaginosis is to be diagnosed and managed effectively in both general and specialist practice.

Adolescent↗
PubMed1996

Discounting the future: influence of the economic model.

OBJECTIVE: To consider the effect of the economic discount rate on health care policy and the rationale for discounting the collective future of society generally. DESIGN: A review of the concept of discounting the future vis à vis the present from the points of view of individuals (who pass on) and of societies (that continue) and reconsideration of the application of discounting to typical public health scenarios. SETTING: A public health service, within a basically stable society, which can reasonably anticipate a nearly certain future. RESULTS: Discounting necessarily overvalues the "here and now" compared with the future. While applications of discount rates, typical of those employed in health economic studies in recent years, may seem rational in health care programmes directed at middle aged employed people, they do not for the young and the elderly, important recipients of health care. The consequences of discounting do not accord with the aims and objectives of public health. CONCLUSIONS: The "time preferences" of transient individuals within a stable society do not provide a rational basis for time preference of a stable society collectively. Discounting inevitably encourages "short termism" and hence biases public policy decision making. The neoclassical theory that gave rise to the concept of discounting requires revision.

Adolescent↗
PubMed1996

ZG-1494 alpha, a novel platelet-activating factor acetyltransferase inhibitor from Penicillium rubrum, isolation, structure elucidation andbiological activity.

A novel inhibitor of platelet-activating factor (PAF) acetyltransferase, an essential enzyme in the remodeling pathway of platelet-activating factor synthesis, was identified by a high throughout screen of natural product extracts of microbial origin. The compound, ZG-1494 alpha, was isolated from an ethyl acetate extract of a culture broth of Penicillium rubrum through bioassay guided fractionation. The structure of ZG-1494 alpha was determined by spectroscopic methods. A key feature of the structure, which is relatively rare among natural products, is the 5-hydroxy-3-pyrrolin-2-one moiety. A 13C-13C INADEQUATE was utilized to unambiguously determine the regiochemistry of this molecule.

Acetyltransferases↗
PubMed1995

Occupational and environmental exposures and myelodysplasia: a case-control study.

A case-control study of newly diagnosed myelodysplastic syndrome patients investigated lifetime exposures through occupation, environment or hobby by questionnaire, structured and semi-structured interview. The exposure histories of 400 individually matched pairs were compared. Increased or possibly increased odds ratios were observed for radiation (2.05, 95% confidence interval 1.16-3.76), halogenated organics (1.57, 0.97-2.57), metals (1.40, 0.99-2.00), several specific radiation exposures and individual chemicals and for childlessness (1.46, 1.01-2.11). Since myelodysplasia generally carries a poor prognosis, whether or not individuals convert to leukaemia or to other cancer, these findings add to previous reports of exposures implicated in the aetiology of leukaemia and add to the case for minimizing exposures to radiation and halogenated organics.

Adolescent↗
PubMed1995

Base-catalyzed isomerism in elfamycin antibiotics. Structures of ganefromycins epsilon and epsilon 1.

The structures of ganefromycins epsilon (2a) and epsilon 1 (2b) have been determined by spectroscopic techniques. The compounds are isomeric deoxygenated precursors of the parent antibiotics ganefromycins alpha and beta. The nature of the isomerism was determined by chemical interconversion experiments and spectroscope analysis to be a change in configuration at C-21. Evidence is provided for other cases of this type of isomerism in the elfamycin class of antibiotics.

Anti-Bacterial Agents↗
PubMed1994

The effect of MDR-1 gene expression on outcome in acute myeloblastic leukaemia.

Resistance to cytotoxic agents may be encountered during the treatment of acute myeloblastic leukaemia (AML). P-glycoprotein encoded by the MDR-1 gene has been implicated as a potential drug resistance mechanism in leukaemic cells. In recent years, many data have been accrued concerning the expression of P-glycoprotein in leukaemia, and several studies have been published which have related MDR status to outcome in AML. Conclusions as to the effect of P-glycoprotein expression on prognosis in AML have varied widely. The studies are not immediately comparable, since they differ in methodology, treatment regimens, demographic profile and, perhaps most importantly, criteria for positivity of MDR status. The technique of statistical overview (meta-analysis) can be used to pool observational studies. Application of this statistical method to existing studies suggests an estimated relative risk of 0.68 for P-glycoprotein expression with respect to complete remission in AML. Further large studies are required to determine fully the role of P-glycoprotein in AML.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1994

Stable expression of heterologous microtubule-associated proteins (MAPs) in Chinese hamster ovary cells: evidence for differing roles of MAPs in microtubule organization.

To study the effects of microtubule-associated proteins (MAPs) on in vivo microtubule assembly, cDNAs containing the complete coding sequences of a Drosophila 205-kD heat stable MAP, human MAP 4, and human tau were stably transfected into CHO cells. Constitutive expression of the transfected genes was low in most cases and had no obvious effects on the viability of the transfected cell lines. High levels of expression, as judged by Western blots, immunofluorescence, and Northern blots, could be induced by treating cells with sodium butyrate. High levels of MAPs were maintained for at least 24-48 h after removal of the sodium butyrate. Immunofluorescence analysis indicated that all three MAPs bound to cellular microtubules, but only the transfected tau caused a rearrangement of microtubules into bundles. Despite high levels of expression of these exogenous MAPs and the bundling of microtubules in cells expressing tau, transfected cells had normal levels of assembled and unassembled tubulin. With the exception of the tau-induced bundles, microtubules in transfected cells showed the same sensitivity as control cells to microtubule depolymerization by Colcemid. Further, all three MAPs were ineffective in reversing the taxol-dependent phenotype of a CHO mutant cell line. The absence of a quantitative effect of any of these heterologous proteins on the assembly of tubulin suggests that these MAPs may have different roles in vivo from those inferred previously from in vitro experiments.

Animals↗
PubMed1994

Coronary artery bypass surgery: current practice in the United Kingdom.

OBJECTIVE: To assess current clinical practice in coronary artery bypass surgery and compare it with a previous survey conducted five years ago. SETTING: United Kingdom. DESIGN: Postal questionnaires were sent in March 1993 to 120 consultant cardiac surgeons currently performing coronary artery bypass surgery. 104 (87%) were returned by May 1993. RESULTS: The 104 surgeons who returned the questionnaire performed an estimated total of 25,234 coronary artery bypass operations in 1992 with an average case load per surgeon similar to that in 1987 (243 v 214, NS). The internal mammary artery was regarded as the conduit of choice by 101 surgeons (97%) and was used in 93% of bypass grafts to the left anterior descending coronary artery compared with 73% in 1987 (p < 0.001) but only in 7% of grafts to the circumflex and right coronary systems. There was also a significant increase in the number of surgeons using both internal mammary arteries (88% v 59%, p < 0.01) but only a small increase in those using the internal mammary artery as a sequential graft (55% v 44%, NS). The age of the patient remains one of the main contraindications to the use of the internal mammary artery (40%), together with insufficient mammary flow (42%), endarterectomy (22%), and unstable angina (17%). The right gastroepiploic and inferior epigastric arteries were used only occasionally (3%) when the internal mammary artery or the saphenous vein were not available. Most surgeons (96%) still advocate the use of aspirin to enhance graft patency, with 87% of surgeons continuing treatment indefinitely, compared with 50% in the previous survey (p < 0.001). As for methods of myocardial protection, 72% of surgeons used cardioplegic arrest whereas 28% preferred intermittent aortic cross clamping and fibrillation. CONCLUSIONS: It is the consensus among British cardiac surgeons that the internal mammary artery is the graft conduit of choice. Its use has been significantly extended over the past five years (1987 to 1992) suggesting a quick response to advancing scientific knowledge. The use of alternative arterial conduits is still limited, perhaps as a reflection of the relative lack of information on their long-term performance. The recently advocated technique of retrograde cardioplegia and continuous warm cardioplegia is not yet popular.

Age Factors↗
PubMed1994

Effect of systemic vasodilators on internal mammary artery flow. Implications for postoperative treatment after myocardial revascularization.

Postoperative spasm of the internal mammary artery graft can cause morbidity and mortality after myocardial revascularization. To our knowledge, the ability of systemic vasodilators to overcome internal mammary artery spasm has not been studied clinically. In 50 patients in whom the left internal mammary artery was used for myocardial revascularization, we have investigated the effect of five agents on internal mammary artery free flow: normal saline, dobutamine, glyceryl trinitrate, sodium nitroprusside, and enoximone, a phosphodiesterase III inhibitor. After the internal mammary artery was harvested, free flow was measured under controlled hemodynamic conditions before any pharmacologic intervention (flow 1) and a mean of 18.5 +/- 3 (standard deviation) minutes after a systemic infusion of one of the five agents was begun (flow 2). The increase in free flow expressed as a percentage of initial flow was greater for enoximone (94% +/- 24%) than for normal saline (18% +/- 11%), dobutamine (40% +/- 27%), and glyceryl trinitrate (52% +/- 36%) (all three p < 0.01). The increase in flow for sodium nitroprusside (78% +/- 37%) was greater than for normal saline and dobutamine (both p < 0.05). We therefore recommend the systemic use of enoximone and sodium nitroprusside, in rank order, to prevent and treat postoperative spasm of the internal mammary artery.

Blood Flow Velocity↗
PubMed1994

Topoisomerase II alpha expression in acute myeloid leukaemia and its relationship to clinical outcome.

The treatment of acute myeloid leukaemia (AML) is often complicated by resistance to chemotherapeutic drugs. Many of the most effective drugs used to treat haematological malignancies target the nuclear enzyme topoisomerase II. Resistance to these drugs in vitro has been associated with quantitative and qualitative changes in the enzyme. In this study, we have investigated topoisomerase II mRNA expression in leukaemic blasts from 23 AML patients. Expression levels ranged from 1-47% relative to the haemopoietic cell line HL60 in 16 evaluable patients. Thirteen of 16 patients achieved complete remission (CR). We have therefore chosen ease of entry into CR as the most sensitive clinical correlate. Decreased topoisomerase II mRNA expression in vitro results in drug resistance. The clinical relevance of reduced expression is not known. All cases of AML and de novo AML have been studied separately. We are unable to identify a correlation between topoisomerase II mRNA levels and ease of entry into CR in either of these groups. Taking these findings into account, group size calculations have been undertaken and indicate that a multi-centre study of this question is warranted.

Adolescent↗
PubMed1993

A look at the statistical overview (or meta-analysis)

In essence, the statistical overview (or meta-analysis) does little more than many medical scientists and practising clinicians have been attempting for years: estimating the average size of an effect from an apparently disparate medical literature. The statistical overview provides a method of pooling the results of comparable trials (or observational studies) which, on their own, may be too small to demonstrate a 'statistically significant' effect. The role for the overview is obvious, the method is relatively simple, but the findings have to be interpreted cautiously, since joining the hypothesis post hoc contravenes one of the essential principles of scientific enquiry. The use of the statistical overview and some of its pros and cons are illustrated in four clinical examples.

Cholesterol↗
PubMed1992

A case control study of factors associated with macroscopic breast cysts.

Women who have a breast cyst aspirated are at increased risk of developing breast cancer. We present an age-matched case control study comparing the reproductive characteristics of 352 women who had a breast cyst aspirated with a control group of 352 contemporaneous clinically normal women. Women with breast cysts were more likely to be nulliparous [odds ratio (OR) = 2.28, 95% confidence interval (CI) = 1.34-3.88] or have a late age at first live birth (chi 2 trend = 5.6, P less than 0.025), and a late menopause (chi 2 trend = 4.3, P less than 0.05). They were less likely to have ever used the oral contraceptive pill (OR = 0.38, 95% CI = 0.26-0.55) or to have used the pill for a short duration (chi 2 trend = 16.8, P less than 0.001), and were less likely to have had a hysterectomy (OR = 0.58, 95% CI = 0.36-0.93). They were more likely to wear a small bra (chi 2 trend = 18.6, P less than 0.001) and bra cup (chi 2 trend = 5.6, P less than 0.025). Nulliparity, late age at first live birth and late menopause are factors common to breast cancer risk.

Adult↗
PubMed1992

Median sternotomy wound dehiscence: a retrospective case control study of risk factors and outcome.

Over a 5-year period from 1985 to 1989, 2760 patients underwent open heart surgery at the University Hospital of Wales. Of these, 44 (1.6%, 35 men, mean age 61 years) developed median sternotomy dehiscence 2-40 (median 9) days after surgery. Infection was an associated factor in 18 patients (41%) and Staphylococcus aureus the predominant isolate in seven of those. Thirty-seven patients underwent rewiring of the sternotomy wound and seven patients underwent debridement, removal of wires and delayed closure. In those undergoing rewiring, sternal stability was maintained in 34 patients (92%). There were seven deaths (16%), of which two were considered to be wound-related. Median hospital stay of survivors was 34 (range 16-84) days. Comparison with 88 matched controls by univariate analysis showed preoperative chronic obstructive airways disease, reduced FEV1/FVC ratio (both P < 0.001) and smoking (P < 0.05) were all more common in the dehiscence group. In addition, reoperation for bleeding (P < 0.05), prolonged bypass time, postoperative ventilation period and length of stay in the intensive care unit (all P < 0.001) were more common in the study group.

Cardiac Surgical Procedures↗
PubMed1992

Smoking: its influence on survival and cause of death.

Smoking is strongly associated with age-specific death rates for a number of diseases. Increased age-specific death rates for a disease may imply either more deaths from the disease with increased absolute lifetime risk, or earlier deaths, without increased absolute lifetime risk. The British doctor smoking data are re-analysed using lifetable methods for survival, cumulative mortality and the disease-specific cumulative mortality. The most significant effect of smoking is on survival: life shortening amounts to three years for light smokers, five for moderate smokers, and eight for heavy smokers, compared with those who never smoked. Smoking increases the absolute number of deaths from some causes, including lung cancer; for other causes, including ischaemic heart disease, it brings forward death without increasing the absolute number of deaths. The smoking associations with more or earlier death have implications for research into the mechanisms of disease causation, for health promotion, for rational health-care planning, and for social policy.

Adult↗
PubMed1992

Reproductive factors associated with mastalgia.

Mastalgia has been classified as an aberration of the normal, rather than a disease. We present an age-matched, case-control study which compares the reproductive factors of patients with severe cyclical and noncyclical mastalgia with control groups of women who presented to a breast clinic but in whom no clinical abnormality was found and who did not later develop breast disease. There were few statistically significant differences in reproductive factors between the cases and controls, which lends some support to the concept that mastalgia can be considered to be an aberration of the normal.

Breast↗