Search PubMed⌕ Search

Biomedical subjects

J Chapman

Publications and source records attributed to J Chapman.

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

Search for scalar top and scalar bottom quarks in pp collisions at square root s=1.8 TeV.

We have searched for direct pair production of scalar top and scalar bottom quarks in 88 pb-1 of pp collisions at sqrt[s]=1.8 TeV with the CDF detector. We looked for events with a pair of heavy flavor jets and missing energy, consistent with scalar top (bottom) quark decays to a charm (bottom) quark and a neutralino. The numbers of events that pass our selections show no significant deviation from standard model expectations. We compare our results to the next-to-leading order scalar quark production cross sections to exclude regions in scalar quark-neutralino mass parameter space.

Journal Article↗
PubMed2000

Search for a W' boson via the decay mode W'-->munumu in 1.8 TeV pp collisions.

We report the results of a search for a W' boson produced in pp collisions at a center-of-mass energy of 1.8 TeV using a 107 pb-1 data sample recorded by the Collider Detector at Fermilab. We consider the decay channel W'-->&munumu and search for anomalous production of high transverse mass munumu lepton pairs. We observe no excess of events above background and set limits on the rate of W' boson production and decay relative to standard model W boson production and decay using a fit of the transverse mass distribution observed. If we assume standard model strength couplings of the W' boson to quark and lepton pairs, we exclude a W' boson with invariant mass less than 660 GeV/c2 at 95% confidence level.

Journal Article↗
PubMed2000

CLA-1/SR-BI is expressed in atherosclerotic lesion macrophages and regulated by activators of peroxisome proliferator-activated receptors.

BACKGROUND: The scavenger receptors are cell-surface receptors for native and modified lipoproteins that play a critical role in the accumulation of lipids by macrophages. CLA-1/SR-BI binds HDL with high affinity and is involved in the cholesterol reverse-transport pathway. Peroxisome proliferator-activated receptors (PPARs) are transcription factors regulating the expression of genes implicated in lipid metabolism, cellular differentiation, and inflammation. Here, we investigated the expression of CLA-1/SR-BI in macrophages and its regulation by PPARs. METHODS AND RESULTS: CLA-1 is undetectable in human monocytes and is induced upon differentiation into macrophages. Immunohistological analysis on human atherosclerotic lesions showed high expression of CLA-1 in macrophages of the lipid core colocalizing with PPARalpha and PPARgamma staining. Activation of PPARalpha and PPARgamma resulted in the induction of CLA-1 protein expression in monocytes and in differentiated macrophages. Finally, SR-BI expression is increased in atherosclerotic lesions of apoE-null mice treated with either PPARgamma or PPARalpha ligands. CONCLUSIONS: Our data demonstrate that CLA-1/SR-BI is expressed in atherosclerotic lesion macrophages and induced by PPAR activation, identifying a potential role for PPARs in cholesterol homeostasis in atherosclerotic lesion macrophages.

Animals↗
PubMed2000

Taxonomy of singers used as subjects in scientific research.

Criteria for determining the classification of singers in research has posed numerous problems for both researchers and their readership. Previous attempts at creating usable categories have failed because of disagreement within the professions involved in such research. The object of this paper is to explore and suggest a system in which scientific research related to singing is based on a quantifiable singing standard. Use of the systematic categorization set out in this paper will help to alleviate the questions regarding performance abilities of singers used as subjects in scientific projects and lead to more credible results. Nine singer categories have been consolidated and based on proven performance achievement. These categories range from superstar (household name) to local community and amateur singers with comprehensive subcategories under each topic for each type of singer, that is, opera, pop, jazz, etc.

Humans↗
PubMed2000

INFLAMET: an image analyzer to display erythrocyte adhesiveness/aggregation.

Background: Due to a lack of simple, inexpensive, and real-time methodology, the state of erythrocyte adhesiveness/aggregation is not measured in daily practice by most clinicians. Methods: We measured the state of erythrocyte adhesiveness/aggregation before and following the administration of intravenous high-dose gamma globulins in 18 patients with various autoimmune diseases using a simple slide test and image analysis system (INFLAMET). Results: A significant (P=0.01) increment in the state of erythrocyte adhesiveness/aggregation (from 2+/-3 to 8+/-9 arbitrary units) was noted in the entire study group despite a significant (P=0.008) decrement (from 350+/-97 to 323+/-127 mg%) in the concentration of fibrinogen and no significant change in the erythrocyte sedimentation rate (32+/-30 mm/h before and 35+/-29 mm/h following administration of gamma globulin). Conclusions: By using a simple slide test and image analysis, we were able to provide relevant rheological information that was not available from either of the routine indirect tests, i.e. the Westergren erythrocyte sedimentation rate and the concentration of fibrinogen.

Journal Article↗
PubMed2000

The influence of assessments on students' motivation to learn in a therapy degree course.

PURPOSE: This paper reports a study which attempted to examine the influence of a varied assessment programme on student motivation to learn in an undergraduate therapy degree course. METHODS: In March 1997 a questionnaire was distributed to 98 third-year occupational therapy and physiotherapy students at the Southampton University School of Occupational Therapy and Physiotherapy. Using closed and open questions the questionnaire required the students to consider all the assessments they had taken in their 3 years of study and provide information about which type of assessment they found most motivating for their learning, and why. RESULTS AND CONCLUSIONS: The results revealed that students found a wide range of assessments motivating. There was some satisfaction with the mix and range of assessments. Three assessments emerged as the most motivating for student learning: Clinical/fieldwork II and III and Methods of inquiry III. In addition, four factors associated with assessment appeared to influence student motivation: perceived relevance and content of the assessment, enthusiastic lecturers and group influences. These factors need to be explored in more detail but in order to do so, educators need to be prepared to engage in an open dialogue with students about the learning climate that is created within higher education.

Education, Medical, Undergraduate↗
PubMed2000

The effectiveness of NGO campaigning: lessons from practice.

This article looks at the lessons learned in reviewing two long-running international campaigns, one to promote breast-feeding in Ghana, and the other against the use of child labor in the carpet industry in India. In particular, it focuses on understanding the nature of campaigns and what makes them effective. It asserts that campaigns are not linear or mechanistic, but need to be understood as passing through various stages and requiring different kinds of action at different levels and at different times. The variety of work and skills thus required makes it vital that the various organizations involved collaborate with each other. In particular, grassroots mobilization has a role that is often forgotten in bringing about sustained policy change.

Africa↗
PubMed2000

Increased leukocyte aggregation induced by gamma-globulin: a clue to the presence of pseudoleukopenia.

BACKGROUND: Previous articles have reported the appearance of leukopenia after the administration of high-dose intravenous gamma-globulins. METHODS: A simple slide test was used to reveal the state of leukocyte aggregation (LA) in the peripheral blood as well as the absolute number of leukocytes in the slides. RESULTS: A significant (P < 0.00001) increment was noted in the state of LA, from 9 +/- 6% before to 25 +/- 11% after gamma-globulin administration. This was accompanied by a significant (P < 0.0004) reduction in the number of white blood cells in the peripheral blood (from 8433 +/- 3905 to 6550 +/- 3252 cells/mm3) but no significant change in the absolute number of the cells as determined by the leukocyte count per high power field in the peripheral slides. CONCLUSIONS: We raise the possibility that the leukopenia reported in some patients after the intravenous administration of high dose gamma-globulin is explained in part by the agglutination effect of the drug.

Adolescent↗
PubMed2000

New functional promoter polymorphism, CETP/-629, in cholesteryl ester transfer protein (CETP) gene related to CETP mass and high density lipoprotein cholesterol levels: role of Sp1/Sp3 in transcriptional regulation.

A new polymorphism located at position -629 (CETP/-629A/C) in the promoter of the cholesteryl ester transfer protein (CETP) gene is described. The -629A allele was associated with lower CETP mass (P<0. 0001) and higher high density lipoprotein cholesterol (P<0.001) than the C allele in a sample of 536 control subjects from the ECTIM study. Transfection studies in HepG2 cells with a luciferase expression vector incorporating a 777-bp fragment of the CETP promoter and containing either A or C at position -629 showed significantly lower luciferase activity with the promoter fragment of the A allele (-25%, P<0.05). By gel-shift assay, DNA-protein interactions were evaluated in nuclear extracts of HepG2 cells with the use of 2 probes (A or C probe) composed of 20 bp of the promoter sequence surrounding the polymorphic site. Two specific complexes of distinct migration rate were identified with the A and the C probe. Competition with an excess of oligonucleotide containing the Sp1 consensus binding site showed that a protein(s) of the Sp transcription factor family was implicated in complex formation with the A probe but not with the C probe. Incubation with specific antibodies indicated that Sp1 and Sp3 bound specifically to the A probe. We introduced mutations in the -629-Sp1 binding site to test its functionality and to define the characteristics of transcription factor binding. We showed, by gel-shift assay, that no nuclear proteins bound to the mutated sequence. Transient transfection of HepG2 cells revealed that the expression of the mutated fragment was significantly increased compared with that of the A promoter fragment (25%, P<0.05). The mutated fragment displayed the same activity as that of the C promoter. These results indicate that Sp1 and/or Sp3 repress CETP promoter activity, whereas nuclear factors binding the C allele are without effect on promoter expression.

Adult↗
PubMed2000

Effect of loperamide on Na+/D-glucose cotransporter activity in mouse small intestine.

The mu-opioid agonist loperamide is an antidiarrhoeal drug which inhibits intestinal motility and secretion. Its anti-absorptive effects are less well investigated, but may be mediated through calmodulin. We have investigated further the effect of loperamide on the intestinal Na+-dependent D-glucose transporter (SGLT1). Brush-border membrane vesicles were prepared from mouse small intestine, and uptake of [3H]glucose was measured. Na+-dependent glucose uptake displayed the typical overshoot at 34 s; the peak value was 1.6 nmol mg(-1). The overshoot disappeared in the presence of phlorizin or when Na+ was replaced by K+. Extravesicular loperamide dose-dependently inhibited SGLT1 activity with an IC50 value of 450 micromol L(-1). Loperamide displayed a mixed inhibition type: the apparent Vmax decreased from 0.9 to 0.5 nmol mg(-1)/15 s, the apparent Km increased from 0.23 to 1.13 mmol L(-1) glucose. Na+ kinetics were more complex, but loperamide inhibited net glucose uptake by 90% at 100 mmol L(-1) Na+. Glucose uptake was unchanged by agents affecting calmodulin activity. Loperamide inhibited intestinal Na+, K+-ATPase activity, whilst sucrase activity was unaffected. SGLT1 activity was inhibited by loperamide, but this effect was not mediated through calmodulin. As this action is only evident at high concentrations of loperamide a nonspecific mechanism may be involved.

Animals↗
PubMed2000

Creutzfeldt-Jakob disease profile in patients homozygous for the PRNP E200K mutation.

We identified 70 Creutzfeldt-Jakob disease patients with the previously described E200K mutation in the prion protein gene. The purpose of this study was to define the clinical features of E200K homozygous patients (n = 5), compared with heterozygotes. We found a statistically significant younger age at disease onset for the homozygous patients, although the average age at onset in this group was still in midlife. Disease features were not statistically different in the two groups. Possible explanations are discussed.

Adult↗
PubMed2000

A longitudinal study of high scorers on the hypomanic personality scale.

Former college students (n = 36) identified by high scores on the Hypomanic Personality Scale (HYP; Eckblad & Chapman, 1986) were compared with control participants (n = 31) at a 13-year follow-up assessment. As hypothesized, the HYP group reported more bipolar disorders and major depressive episodes than the control group. The HYP group also exceeded the control group on the severity of psychotic-like experiences, symptoms of borderline personality disorder, and rates of substance use disorders. HYP group members with elevated scores on the Impulsive-Nonconformity Scale (Chapman et al., 1984) experienced greater rates of bipolar mood disorders, poorer overall adjustment, and higher rates of arrest than the remaining HYP or control participants.

Adult↗
PubMed2000

Progress in improving the pathogen safety of red cell concentrates.

Current methods of preparing red cell concentrates do not include a process step to decontaminate pathogens potentially present in the transfusion product. Although substantial progress has been made in the reduction of the frequency of transmission of HIV, HCV, HBV and HTLV-I as a result of the implementation of diagnostic screening processes, the need for further reduction in transmission rate of these viruses remains. In addition, there are viruses which are known to be be present in blood but for which no screening test has been implemented to remove contaminated units from the blood supply. These viruses include but are not limited to TTV, HGV and Parvo B19. Finally, the lack of a pathogen inactivation process for red cells maintains the blood supply in a state of vulnerability to new viruses or virus variants as they enter the donor population. Recently, substantial progress has been made in the research and development of a class of chemical compounds designated as INACTINE. These compounds are being investigated for their potential to inactivate viruses in red cells without adversely affecting their physiologic function. One of the INACTINE compounds, designated as PEN110, is now in the clinical trial phase of development.

Antiviral Agents↗
PubMed1999

Preliminary evidence for anticipation in genetic E200K Creutzfeldt-Jakob disease.

Creutzfeldt-Jakob disease (CJD) linked to the E200K mutation of the prion protein (PrP) gene presents within a wide range of phenotypic heterogeneity, including the age at disease onset. We report an earlier disease onset for mutation carriers of the offspring generation when compared with that of their parents, suggesting the possibility of anticipation. A still unidentified environmental or genetic element may affect the age at onset in mutation carriers of different generations.

Age Factors↗