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Biomedical subjects

S Edwards

Publications and source records attributed to S Edwards.

At least 55 records · Page 3Linked to original sources
PubMed1997

Life stressors, neighborhood disadvantage, and resources: a focus on inner-city children's adjustment.

Examined the contribution of particular stressors and resources to inner-city children's adjustment. Fourth, 5th, and 6th graders (N = 315; 66% from ethnic minority groups) reported on their recent exposure to stressful events and neighborhood disadvantage, their perceptions of self-worth and social support, and their behavioral and academic adjustment. Hierarchical regressions indicated unique contributions of stressful events and neighborhood disadvantage to predicting antisocial behavior; higher levels of self-worth and family support were related to lower levels of antisocial behavior, but higher levels of peer support were related to higher levels of antisocial behavior. Furthermore, whereas family support buffered the relation between stressful events and antisocial behavior, peer support exacerbated the effect of stressors on behavioral maladjustment.

Achievement↗
PubMed1997

Recording blood pressure.

The blood pressure can reveal much about a patient's state of health. A number of variables can affect blood pressure measurement.

Blood Pressure↗
PubMed1996

A description of age, sex, and site distributions of colon carcinoma in three geographic areas.

BACKGROUND: Site of the carcinoma within the colon in relation to age and sex may provide clues into the etiology of the disease. Incidence of colon carcinoma by age, sex, and tumor site at a population-based level are reported infrequently. The goal of this study was to describe the distribution of colon carcinoma (excluding cancers of the rectosigmoid junction and rectum) by age at diagnosis, sex, and site of the tumor within the colon. These factors were also evaluated in conjunction with disease stage at the time of diagnosis. METHODS: Data from three geographically distinct populations were used to describe rates of colon carcinoma and the distribution of tumors by age, tumor site, and stage at diagnosis. All colon carcinoma cases diagnosed within a 3-year period within the areas are included. RESULTS: Approximately 50% of all cancers in men and greater than 50% of cancers in women were in the proximal segment of the colon. Men who were diagnosed prior to age 50 and both men and women diagnosed at age 70 or older had predominantly proximal cancers. People with proximal cancers and people diagnosed prior to age 50 were more likely to have more advanced disease. CONCLUSIONS: Both men and women have more proximal cancers with advancing age, which are associated with more advanced disease. Observed trends in cancer site distributions could reflect screening practices, environmental and genetic factors, or a combination of these variables.

Adult↗
PubMed1996

Molecular, functional and evolutionary characterization of the gene encoding HMG-CoA reductase in the fission yeast, Schizosaccharomyces pombe.

The synthesis of mevalonate, a molecule required for both sterol and isoprene biosynthesis in eukaryotes, is catalysed by 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase. Using a gene dosage approach, we have isolated the gene encoding HMG-CoA reductase hmgl+, from the fission yeast Schizosaccharomyces pombe (Accession Number L76979). Specifically, hmgl+ was isolated on the basis of its ability to confer resistance to lovastatin, a competitive inhibitor of HMG-CoA reductase. Gene disruption analysis showed that hmgl+ was an essential gene. This result provided evidence that, unlike Saccharomyces cerevisiae, S. pombe contained only a single functional HMG-CoA reductase gene. The presence of a single HMG-CoA reductase gene was confirmed by genomic hybridization analysis. As observed for the S. cerevisiae HMGlp, the hmgl+ protein induced membrane proliferations known as karmellae. A previously undescribed 'feed-forward' regulation was observed in which elevated levels of HMG-CoA synthase, the enzyme catalysing the synthesis of the HMG-CoA reductase substrate, induced elevated levels of hmgl+ protein in the cell and conferred partial resistance to lovastatin. The amino acid sequences of yeast and human HMG-CoA reductase were highly divergent in the membrane domains, but were extensively conserved in the catalytic domains. We tested whether the gene duplication that produced the two functional genes in S. cerevisiae occurred before or after S. pombe and S. cerevisiae diverged by comparing the log likelihoods of trees specified by these hypotheses. We found that the tree specifying post-divergence duplication had significantly higher likelihood. Moreover, phylogenetic analyses of available HMG-CoA reductase sequences also suggested that the lineages of S. pombe and S. cerevisiae diverged approximately 420 million years ago but that the duplication event that produced two HMG-CoA reductase genes in the budding yeast occurred only approximately 56 million years ago. To date, S. pombe is the only unicellular eukaryote that has been found to contain a single HMG-CoA reductase gene. Consequently, S. pombe may provide important opportunities to study aspects of the regulation of sterol biosynthesis that have been difficult to address in other organisms and serve as a test organism to identify novel therapies for modulating cholesterol synthesis.

Amino Acid Sequence↗
PubMed1996

Beneficial effects of RheothRx injection in patients receiving thrombolytic therapy for acute myocardial infarction. Results of a randomized, double-blind, placebo-controlled trial.

BACKGROUND: RheothRx (poloxamer 188) is a surfactant with hemorheological and antithrombotic properties that reduces myocardial reperfusion injury in animal models of myocardial infarction. The purpose of the present study was to evaluate the safety and efficacy of adjunctive therapy with poloxamer 188 in patients receiving thrombolytic therapy for acute myocardial infarction. METHODS AND RESULTS: In this multicenter trial, we randomized 114 patients to a 48-hour infusion of poloxamer 188 or vehicle placebo beginning immediately after the initiation of thrombolytic therapy. Tomographic imaging with 99mTc sestamibi before reperfusion and again 5 to 7 days after the infarction was used to determine myocardium at risk for infarction, infarct size, and myocardial salvage. Radionuclide angiography at 5 to 7 days after infarction was used to measure left ventricular ejection fraction. The treated and control groups had comparable baseline characteristics, time to thrombolytic administration, and time to treatment with poloxamer 188 or placebo. Poloxamer 188-treated patients demonstrated a 38% reduction in median myocardial infarct size (25th and 75th percentile) compared with placebo (16% [7, 30] versus 26% [9, 43]; P = .031), greater median myocardial salvage (13% [7, 20] versus 4% [1, 15]; P = .033), and a 13% relative improvement in median ejection fraction (52% [43, 60] versus 46% [35, 60]; P = .020). Poloxamer 188 treatment also resulted in a reduced incidence of reinfarction (1% versus 13%; P = .016). Poloxamer 188 was well tolerated without adverse hemodynamic effects or significant organ toxicity. CONCLUSIONS: Adjunctive therapy with poloxamer 188 resulted in substantial benefit in this randomized trial, including significantly smaller infarcts, greater myocardial salvage, better left ventricular function, and a lower incidence of in-hospital reinfarction. Although the mechanisms are unproven, poloxamer 188 treatment may accelerate thrombolysis, reduce reocclusion, and ameliorate reperfusion injury.

Adult↗
PubMed1996

Enhanced secretory ability for the human factor VIII light chain produced in baculovirus-infected insect cells.

The light and truncated heavy chains of human factor VIII, expressed separately in baculovirus-infected insect cells, exhibited different secretory behaviour when compared with each other and with a biologically active fusion molecule of the truncated heavy and light chains. The light chain was very efficiently secreted into culture medium, as judged by high extracellular protein levels and the absence of evidence for light chain retention within cells. Alternatively, proteins containing the heavy chain sequence were poorly secreted and appeared to be sequestered within cells, suggesting that regions within the heavy chain are responsible for the low levels of secreted protein which have generally been observed for recombinant factor VIII.

Animals↗
PubMed1996

A demonstration of virtual reality in free-flying honeybees: Apis mellifera.

Two experiments are reported on virtual reality illusion in free-flying honeybees. In the first experiment, subjects are trained on a simultaneous discrimination between two colored targets, one of which contains a sucrose reward. The ability to be influenced by a virtual reality illusion was assessed during an extinction test in which the training stimuli were a mirage of those used during acquisition. The results indicate that the bees consistently attempt to land on the previously rewarded color despite the fact that it is not there. In a second experiment, bees were unable to discriminate between two simultaneously presented, identically colored targets--one of which was real, the other a mirage.

Animals↗
PubMed1996

Effects of caffeine, practice, and mode of presentation on Stroop task performance.

A series of experiments were designed to investigate the effects of 125 and 250 mg caffeine, or placebo, on performance of the Stroop task. Caffeine had no effect on performance of either the classic colour-word version or a numerical version of the task, either using computerised presentation of the stimuli or a traditional card version. However, significant practice effects were found using a within-subjects design with the card version of the task, and differences were found between performance in the card and computerised versions of the task. It is concluded that at these doses, caffeine does not significantly affect Stroop performance. It is also suggested that practice effects in studies using within-subject designs may be a problem when attempting to detect subtle effects of drugs on cognitive performance, and that the computerised version of the Stroop task may not be an exact analogue of the traditional card version.

Adolescent↗
PubMed1996

Antibody isotype responses to experimental infection with bovine herpesvirus 1 in calves with colostrally derived antibody.

Calves, both positive and negative for maternal antibody to bovine herpesvirus 1 (BHV-1), were infected with BHV-1 and their serum antibody isotype responses were measured post-infection. In the case of maternal antibody negative calves there was a classical humoral response to the virus with an early IgM peak followed by IgG1 and IgG2 responses. In maternal antibody positive calves, although infection was established, no active antibody response was detected in serum except for a transient IgM peak in a single calf. By contrast, a delayed-type hypersensitivity test response could be elicited in both groups of calves by intradermal inoculation of nucleocapsid antigen at 4.5 months after the initial infection. The intradermal antigen also stimulated an antibody response. In calves with high levels of maternal antibody at the start of the experiment, and which were not subsequently infected, maternal antibody waned to negative levels by seven months of age. They were skin test negative and did not show a serological response to skin test antigen. It was concluded that isotype specific serology could not be used to distinguish calves with passive immunity to BHV-1 from those with active immunity and putative latent infection. Although the skin test had potential to provide such a distinction, it could compromise future serological monitoring of the animals.

Animals↗
PubMed1996

A European inter-laboratory trial to evaluate the reliability of serological diagnosis of bovine herpesvirus 1 infections.

The detection of cattle latently infected with bovine herpesvirus 1 (BHV1) is of importance in control programs and in international trade activities. Therefore, tests to detect specific antibodies in serum must be highly sensitive. To evaluate the reliability of serological diagnosis of BHV1 infections in Europe, seventeen laboratories in 15 European countries were asked to determine BHV1-specific antibodies in a panel of bovine serum samples using the serological tests available in their laboratory. Laboratory tests included virus neutralisation tests (1, 2 and 24 h), indirect immunofluorescence tests and ELISAs. The serum panel consisted of 12 duplicate lyophilised samples which were randomly coded from 1 to 24 and included negative, weak- and strong-positive samples as well as international reference sera. Virus neutralisation tests and ELISAs showed a high specificity. All participants using neutralisation tests (n = 13) scored the negative samples correctly. Twenty three of 25 ELISAs showed 100% specificity. A serum sample obtained at day 7 after infection was scored as negative by all tests except one home-made blocking ELISA. Samples obtained at day 9 and at day 11 after infection were scored as positive by approximately half and by all tests, respectively. To score the weak-positive European reference standard (EU2) correctly, 24 h neutralisation tests (positive by 8 of 9 laboratories) and home-made blocking ELISAs (positive by 5 of 6 laboratories) were the most reliable. The results indicate that standardisation is urgently needed to ensure that BHV1-infected animals with low antibody titres are recognised.

Animals↗
PubMed1996

Treacher Collins syndrome may result from insertions, deletions or splicing mutations, which introduce a termination codon into the gene.

Treacher Collins syndrome is an autosomal dominant disorder of craniofacial development the features of which include conductive hearing loss and cleft palate. Recently, the Treacher Collins syndrome gene (TCOF1) has been positionally cloned and a series of five mutations within the coding sequence of the gene identified. In the current investigation, seven exons of TCOF1 have been identified which has permitted the identification of additional mutations in the gene. The mutations that have been identified are three distinct deletions and an insertion, which cause a frameshift, and a missense mutation which inactivates a donor splice site with extension of transcription into the intron. To date, all 10 of the mutations which have been reported result in a premature termination codon and are unique to a given family. As these mutations are spread throughout the gene, these observations provide further support for the hypothesis that Treacher Collins syndrome results from haploinsufficiency, although a dominant negative effect cannot, at this stage, be excluded.

Exons↗
PubMed1996

Patient characteristics affecting attendance at general outpatient clinics.

A study was carried out to identify the characteristics of children who do not attend appointments at general outpatient clinics. Over six months, 359 children who had an appointment at a general clinic were studied using a questionnaire given to parents (74% response rate) and by inspection of case notes. Based on their first appointment in the study period, children were divided into 'attenders' (n = 262) and 'non-attenders' (n = 97) for analysis. Non-attenders were significantly more likely to have one or more of the following characteristics: lower social class, poorer housing, unmarried parent(s) (56% v 33%), longer journey to clinic (35 v 27.6 minutes), more appointments per year (4.2 v 3.3), poorer past attendance record, and received their appointment by post (76% v 44%). Surprisingly parents of non-attenders rated their children to have a significantly more severe illness than those who attended. These results suggest that attendance is primarily determined by social and logistical factors as well as appointment details, rather than illness severity.

Age Factors↗
PubMed1996

"Fast tracking" patients with a proximal femoral fracture.

OBJECTIVE: To assess the management of elderly patients presenting to the accident and emergency (A&E) department with a proximal femoral fracture. METHODS: A retrospective audit carried out on 30 patients with proximal femoral fracture showed an unacceptably long waiting time in the A&E department. A new "fast track" system for managing these patients, involving the use of a flow chart for expediting admission, was devised. A prospective study of 100 patients > 60 years of age with proximal femoral fracture admitted by fast track system was then carried out. RESULTS: Implementation of the fast track system resulted in earlier admission to the ward (median time to admission 2.5 h v 4.5 h in the retrospective audit, P < 0.001). Eighteen patients were not admitted by fast track during the study period, in some cases because of inconclusive diagnosis or because there was no identifiable orthopaedic bed; mean admission time for this group was 4 h 8 min. CONCLUSIONS: The fast track system was of benefit to all involved, including the patient, A&E staff, ward staff, and orthopaedic personnel.

Aged↗
PubMed1996

Balanitis and balanoposthitis: a review.

OBJECTIVES: To give an overview of the literature on balanitis, with a special emphasis on infective causes. METHOD: A data search was performed using the OVID CD plus Medline 1967-1995, using balanitis and balanoposthitis as textword search strategy. Specific subjects such as anaerobic infection, Zoon's balanitis were sought separately and subgroups combined. Original articles and abstracts were referenced to illustrate each condition. These were mainly English language articles, but included appropriate non-English language papers. CONCLUSIONS: Balanitis is a common condition among genitourinary medicine clinic attendees, the cause often remaining undiagnosed. Many cases are caused by infection, with candida being the most frequently diagnosed. However, gardnerella and anaerobic infections are common, and there are a wide variety of other rarer infective causes. In addition irritant balanitis is probably a contributing factor in many cases. Balanitis which persists and in which the cause remains unclear warrants biopsy.

Bacterial Infections↗