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Biomedical subjects

A Whelan

Publications and source records attributed to A Whelan.

At least 19 recordsLinked to original sources
PubMed2006

Serum levels of soluble CD163 correlate with the inflammatory process in coeliac disease.

BACKGROUND: In coeliac disease, following the introduction of a gluten-free diet, monitoring mucosal disease activity requires repeated small intestinal biopsies. If a test measuring a circulating inflammatory marker was available, this would be clinically valuable. AIM: To determine if levels of soluble CD163, a scavenger receptor shed by tissue macrophages, correlated with the inflammatory lesion in coeliac disease. METHODS: Serum samples were collected from 131 patients with untreated coeliac disease, 40 patients with treated coeliac disease, 92 non-coeliac disease control subjects and 131 healthy controls. A capture enzyme linked immunosorbance assay was established to measure levels of soluble CD163 in sera. The extent of the histological lesion in coeliac biopsies was assessed using a Marsh grading system. RESULTS: Levels of CD163 in untreated coeliac subjects were significantly elevated when compared with the treated coeliac patients, the disease control group and the healthy control subjects (P < 0.0001 in each instance). Moreover, coeliac patients with the most marked histological lesion (Marsh 3) had significantly higher levels of soluble CD163 than patients with Marsh grade 2 lesions (P < 0.0004), with grade 1 lesions (P < 0.0001) and grade 0 lesions (P < 0.0001). CONCLUSIONS: Measurement of soluble CD163 may be a useful method of monitoring the inflammatory lesion in coeliac disease.

Adult↗
PubMed2005

Interferon-gamma responses to ESAT-6 in tuberculosis patients early into and after anti-tuberculosis treatment.

OBJECTIVE: To investigate T-cell responses to ESAT-6 by an interferon-gamma (IFN-gamma) ex vivo enzyme-linked immunospot (ELISpot) assay in tuberculosis (TB) patients early during treatment and in patients who have completed a course of anti-tuberculosis chemotherapy. DESIGN: T-cell responses following overnight stimulation with 6-kD early secretory antigenic target (ESAT-6) antigen were compared to responses obtained using cells cultured with ESAT-6 for 6 days, using an ELISpot assay. RESULTS: In the ex vivo ELISpot assay, the median IFN-gamma responses in TB patients, irrespective of treatment status, were significantly higher than in healthy BCG-vaccinated controls. In the 6-day ELISpot assay, median IFN-gamma responses were significantly higher in TB patients who had completed treatment than in patients early during therapy. There was considerable individual variability in the degree of expansion of ESAT-6 specific T-cells from day 1 to day 6 in both treatment groups. CONCLUSION: Further studies are required to assess which type of assay provides the best indicator of a memory T-cell response and how ESAT-6 specific T-cells relate to protective immunity in TB infection.

Adult↗
PubMed2002

Effects of human placental lactogen on the expression of CD163 and CD14 on human monocytes in culture.

The effect of human placental lactogen (hPL), a member of the somatomammotrophin family, on the regulation of the scavenger receptor molecules CD14 and CD163 on human monocytes cultured for 48h was investigated. Cells were cultured in the presence or absence of the hormone and also in the presence or absence of IFN-gamma and dexamethasone. Monocytes cultured in the presence of hPL showed a significant increase in the expression of CD14 in both males and females compared to background. When IFN-gamma and dexamethasone were added to the cultures, CD14 expression was decreased and was not rescued by the presence of hPL. hPL alone had no effect on the expression of CD163 on cultured monocytes from either gender, although cells cultured in the presence of IFN-gamma and dexamethasone showed a profound increase in their expression of CD163. This expression was augmented further by the presence of hPL in the cultures over a 48-h period. These results support the hypothesis of a potential role of this hormone in the regulation of the innate immune response.

Anti-Inflammatory Agents↗
PubMed2001

Enhanced contact tracing and spatial tracking of Mycobacterium tuberculosis infection by enumeration of antigen-specific T cells.

BACKGROUND: Identification of individuals latently infected with Mycobacterium tuberculosis is an important part of tuberculosis control. The current method, the tuberculin skin test (TST), has poor specificity because of the antigenic cross-reactivity of purified protein derivative (PPD) with M bovis BCG vaccine and environmental mycobacteria. ESAT-6 is a secreted antigen that is highly specific for M tuberculosis complex, but is absent from M bovis BCG. With an enzyme-linked immunospot (ELISPOT) assay for interferon gamma, we have identified ESAT-6-specific T cells as an accurate marker of M tuberculosis infection. METHODS: We did a prospective, masked study of 50 healthy contacts, with varying but well defined degrees of exposure to M tuberculosis, who attended an urban contact-tracing clinic. We assessed and compared the efficacy of our assay and TST for detection of symptomless infected individuals by correlation of test results with the degree of exposure to an infectious index case. FINDINGS: The ESAT-6 ELISPOT assay results had a strong positive relation with increasing intensity of exposure (odds ratio=9.0 per unit increase in level of exposure [95% CI 2.6--31.6], p=0.001), whereas TST results had a weaker relation with exposure (1.9 [1.0--3.5], p=0.05). By contrast, ELISPOT results were not correlated with BCG vaccination status (p=0.7), whereas TST results were significantly more likely to be positive in BCG-vaccinated contacts (12.1 [1.3--115.7], p=0.03). INTERPRETATION: This new antigen-specific T cell-based assay could allow more accurate identification of symptom-free individuals recently exposed to M tuberculosis, and thereby help to improve tuberculosis control.

Adult↗
PubMed2001

A guinea pig model of low-dose Mycobacterium bovis aerogenic infection.

In order to develop a model of Mycobacterium bovis infection with pathogenetical relevance, a modified version of the Henderson apparatus was used to deliver infectious aerosols directly to the snouts of guinea pigs. Aerosols generated from 10(6), 10(7), 10(8)CFU/ml M. bovis suspensions established disease in every animal, with estimated retained doses of 10, 100, 1000 CFU, respectively. For comparison, other guinea pigs were inoculated with 100 CFU M. bovis intramuscularly (i.m.). Pathology and bacterial colonisation of lungs and spleen varied according to the dose and route of inoculation. Animals inoculated i.m. gave a significant cutaneous tuberculin hypersensitivity reaction earlier after testing than those infected aerogenically. A serological response to M. bovis antigens was detected in all infected animals. Intensity of antigen recognition was dose-dependent and although the range of antigens recognised varied between animals, a 25 kDa antigen present in the cell fraction was serodominant. Thus, a reproducible guinea pig model has been defined that may be suitable for virulence, vaccination, and immunological studies.

Administration, Intranasal↗
PubMed2001

Reforming the core clerkship in internal medicine: the SGIM/CDIM Project. Society of General Internal Medicine/Clerkship Directors in Internal Medicine.

Dramatic changes in health care have stimulated reform of undergraduate medical education. In an effort to improve the teaching of generalist competencies and encourage learning in the outpatient setting, the Society of General Internal Medicine joined with the Clerkship Directors in Internal Medicine in a federally sponsored initiative to develop a new curriculum for the internal medicine core clerkship. Using a broad-based advisory committee and working closely with key stakeholders (especially clerkship directors), the project collaborators helped forge a new national consensus on the learning agenda for the clerkship (a prioritized set of basic generalist competencies) and on the proportion of time that should be devoted to outpatient care (at least one third of the clerkship). From this consensus emerged a new curricular model that served as the basis for production of a curriculum guide and faculty resource package. The guide features the prioritized set of basic generalist competencies and specifies the requisite knowledge, skills, and attitudes/values needed to master them, as well as a list of suggested training problems. It also includes recommended training experiences, schedules, and approaches to faculty development, precepting, and student evaluation. Demand for the guide has been strong and led to production of a second edition, which includes additional materials, an electronic version, and a pocket guide for students and faculty. A follow-up survey of clerkship directors administered soon after completion of the first edition revealed widespread use of the curricular guide but also important barriers to full implementation of the new curriculum. Although this collaborative effort appears to have initiated clerkship reform, long-term success will require an enhanced educational infrastructure to support teaching in the outpatient setting.

Clinical Clerkship↗
PubMed2001

Flow cytometric measurement of intracellular migration inhibition factor and tumour necrosis factor alpha in the mucosa of patients with coeliac disease.

There is increasing evidence that proinflammatory cytokines contribute to many of the small intestinal features in coeliac disease. The aim of the study was to investigate the expression of two proinflammatory cytokines, migration inhibition factor (MIF) and tumour necrosis factor alpha (TNF-alpha) in duodenal biopsy specimens from patients with coeliac disease on a gluten-free diet and normal control subjects. A flow cytometric system was used to analyse intracellular protein levels of MIF and TNF-alpha in freshly isolated cells from duodenal biopsies taken from 12 patients with treated coeliac disease and 10 healthy control subjects. From the biopsy specimens, single cell suspensions of the epithelium and lamina propria were prepared using EDTA/DTT and enzymes. Intracellular cytokine expression was studied in intraepithelial lymphocytes (IELs), lamina propria T cells (LP T) and intestinal epithelial cells using different surface labelling antibodies. MIF protein was constitutively expressed in IELs, LP T cells and epithelial cells from normal intestinal mucosa. In contrast, although TNF-alpha was found in LP T cells, this cytokine was virtually undetectable in either IELs or epithelial cells. In coeliac disease, intracellular levels of MIF were significantly higher in epithelial cells compared with control subjects (P = 0.005). Raised levels of TNF-alpha were found in epithelial cells (P = 0.03) as well as IELs (P = 0.045) from coeliac patients compared with controls. The findings from this study show up-regulated expression of MIF and TNF-alpha in IELs and epithelial cells of histologically normal mucosa in patients with coeliac disease. Increased expression of proinflammatory cytokines in cells occupying the epithelial layer could help explain the rapidity with which the coeliac mucosa may respond to gluten challenge.

Adolescent↗
PubMed2001

Bringing the human genome and the revolution in bioinformatics to the medical school classroom: a case report from Washington University School of Medicine.

The human genome project is revolutionizing medical research and the practice of clinical medicine. To understand and participate in this revolution, physicians must be fluent in human genomics and bioinformatics. At Washington University School of Medicine (WUSM), the authors designed a module for teaching these skills to first-year students. The module uses clinical cases as a platform for accessing information stored in GenBank, Online Mendelian Inheritance in Man (OMIM), and PubMed databases at the National Center for Biotechnology Information (NCBI). This module, which is also designed to reinforce problem-solving skills, has been integrated into WUSM's first-year medical genetics course.

Computer-Assisted Instruction↗
PubMed2001

Use of synthetic peptides derived from the antigens ESAT-6 and CFP-10 for differential diagnosis of bovine tuberculosis in cattle.

In Great Britain an independent scientific review for the government has concluded that the development of a cattle vaccine against Mycobacterium bovis infection holds the best long-term prospect for tuberculosis control in British herds. A precondition for vaccination is the development of a complementary diagnostic test to differentiate between vaccinated animals and those infected with M. bovis so that testing and slaughter-based control strategies can continue alongside vaccination. To date bacillus Calmette-Guérin (BCG), an attenuated strain of M. bovis, is the only available vaccine for the prevention of tuberculosis. However, tests based on tuberculin purified protein derivative cannot distinguish between M. bovis infection and BCG vaccination. Therefore, specific antigens expressed by M. bovis but absent from BCG constitute prime candidates for differential diagnostic reagents. Recently, two such antigens, ESAT-6 and CFP-10, have been reported to be promising candidates as diagnostic reagents for the detection of M. bovis infection in cattle. Here we report the identification of promiscuous peptides of CFP-10 that were recognized by M. bovis-infected cattle. Five of these peptides were formulated into a peptide cocktail together with five peptides derived from ESAT-6. Using this peptide cocktail in T-cell assays, M. bovis-infected animals were detected, while BCG-vaccinated or Mycobacterium avium-sensitized animals did not respond. The sensitivity of the peptide cocktail as an antigen in a whole-blood gamma interferon assay was determined using naturally infected field reactor cattle, and the specificity was determined using blood from BCG-vaccinated and noninfected, nonvaccinated animals. The sensitivity of the assay in cattle with confirmed tuberculosis was found to be 77.9%, with a specificity of 100% in BCG-vaccinated or nonvaccinated animals. This compares favorably with the specificity of tuberculin when tested in noninfected or vaccinated animals. In summary, our results demonstrate that this peptide cocktail can discriminate between M. bovis infection and BCG vaccination with a high degree of sensitivity and specificity.

Amino Acid Sequence↗
PubMed2001

Prophylactic oophorectomy and ovarian cancer surveillance. Patient perceptions and satisfaction.

OBJECTIVE: To evaluate decision making, information gathering, satisfaction and regret in women at increased risk of ovarian cancer who had undergone prophylactic oophorectomy or ovarian cancer surveillance. STUDY DESIGN: Thirty women undergoing prophylactic oophorectomy (median age, 47 years) and 30 women who had undergone ovarian cancer surveillance (median age, 43) completed an in-depth telephone interview consisting of open-ended questions. RESULTS: Most commonly cited concerns before prophylactic oophorectomy included the physical discomfort of surgery and recovery (40%) and issues of immediate menopause and hormone replacement (37%). Fourteen women (47%) would have liked more information prior to surgery. Two women (7%) expressed regret about their decision. The remaining 28 women (93%) undergoing prophylactic oophorectomy expressed no regret about the decision. Nine women (37%) would have liked more information prior to considering ovarian cancer surveillance. Nearly half the women undergoing surveillance did not recall receiving any information about prophylactic oophorectomy as an option. Fifteen women (50%) expressed some regret about ovarian cancer surveillance, and three were frankly dissatisfied. CONCLUSION: Few women undergoing prophylactic oophorectomy had regret about their decision, though half these women would have liked more information prior to surgery. Many women undergoing ovarian cancer surveillance had some regret about or dissatisfaction with their decision.

Adult↗
PubMed2000

Occurrence of IgA and IgG autoantibodies to calreticulin in coeliac disease and various autoimmune diseases.

Calreticulin (CRT), a high-affintiy calcium binding protein and chaperone, was recently identified as one of the targets of autoantibodies in coeliac disease. We evaluated the level of IgA and IgG antibodies to CRT in sera from patients with coeliac disease and various autoimmune diseases. The level of antibodies to gliadin (shown previously to cross-react with CTR), isolated enterocytes and tissue transglutaminase were determined for comparison. The mean level of IgA antibodies to CRT was significantly higher (P< 0.001) in sera from coeliac patients with active disease (139.9+/-11.2 AU/+/-SE) than in healthy controls (20.9+/-1.7 AU). In sera of patients with systemic lupus erythematosus (SLE), insulin dependent diabetes mellitus (IDDM), multiple sclerosis (MS) and autoimmune thyroiditis (AT) or inflammatory bowel disease (IBD) the mean level (25.8+/-3.7 to 38.1+/-5.6 AU) did not exceed the cut-off value. A low level of these antibodies, however, was detected in some sera of patients with MS and IBD. The level of IgG anti-CRT antibodies was increased in coeliac patients (mean 125.4+/-8.0 AU, P< 0.001) when compared to that in healthy controls (33.9+/-2.3 AU). The IgG anti-CRT antibodies were also detected in about 30% of SLE patients sera (54.1+/-3.6 AU, P< 0.001), but the mean level reached only half that detected in coeliac patients.

Adolescent↗
PubMed2000

Vaccination of mice and cattle with plasmid DNA encoding the Mycobacterium bovis antigen MPB83.

A scientific review of bovine tuberculosis in Great Britain has concluded that the development of a cattle vaccine holds the best prospect for long-term disease control. Recent reports of successful DNA vaccination against Mycobacterium tuberculosis in small animal models have raised the possibility of using a similar strategy to produce vaccines against Mycobacterium bovis infection in cattle. To test this possibility, BALB/c mice were immunized with DNA encoding the M. bovis antigen MPB83. The mice responded to vaccination with a mixed IgG1/IgG2a response to the antigen and were protected from intravenous challenge with virulent M. bovis to a similar extent as those vaccinated with bacille Calmette-Guérin. The immunogenicity of the DNA vaccine in cattle was tested, after having established that DNA encoding MPB83 was immunogenic and elicited protective immunity in mice. In these studies, vaccinated animals had strong proliferative responses to MPB83.

Animals↗
PubMed2000

Identification of a Mycobacterium bovis BCG auxotrophic mutant that protects guinea pigs against M. bovis and hematogenous spread of Mycobacterium tuberculosis without sensitization to tuberculin.

Tuberculosis remains one of the most significant diseases of humans and animals. The only currently available vaccine against this disease is a live, attenuated vaccine, bacillus Calmette-Guérin (BCG), which was originally derived from Mycobacterium bovis and despite its variable efficacy is the most widely administered vaccine in the world. With the advent of the human immunodeficiency virus-AIDS pandemic concern has been raised over the safety of BCG. Moreover, since BCG sensitizes vaccinated individuals to the tuberculin test, vaccination with BCG prevents diagnosis of infection in vaccinated individuals. Recently, auxotrophic strains of BCG have been generated by insertional mutagenesis which have been shown to be safer than the parent BCG strain following administration to mice with severe combined immunodeficiency disease. These strains have also been shown to give comparable protection against intravenous and intratracheal challenge of BALB/c mice with M. tuberculosis relative to conventional BCG. Here we report that one of these mutants, a leucine auxotroph of BCG, conferred significant protection of the lungs and spleens of guinea pigs infected with M. bovis and protection of the spleens of guinea pigs infected with M. tuberculosis in the absence of a cutaneous hypersensitivity reaction to tuberculin. Therefore, protective immunity to tuberculosis may, at least in part, be achieved without sensitization to the tuberculin skin test. These results indicate that it may be possible to develop a new generation of vaccines based on BCG that are protective, are safe for use in the immunocompromised, and do not preclude the use of the tuberculin skin test in both humans and animals.

Animals↗
PubMed1999

Cytokines in detoxified patients with chronic alcoholism without liver disease: increased monocytic cytokine production.

BACKGROUND: The aim of the present study was to examine the production of interferon-gamma, tumor necrosis factor-alpha (TNF-alpha), granulocyte-macrophage colony stimulating factor (GM-CSF), interleukin-6 (IL-6), IL-10, IL-4, IL-5, IL-1 receptor antagonist (IL-1RA), and prostaglandin E2 in relation to the number of leukocytes in the blood of detoxified, chronic alcoholic patients without apparent liver disease (AWLD). METHODS: Phytohemagglutinin + lipopolysaccharide-induced production of the above variables as well as the number of white blood cells and differentials were determined in detoxified AWLD patients and normal volunteers. RESULTS: Detoxified AWLD patients have a significantly higher production of IL-6, IL-10, TNF-alpha, GM-CSF, and IL-1RA and significantly increased numbers of leukocytes and neutrophils compared to normal volunteers. CONCLUSIONS: Detoxified AWLD patients show an increased production of proinflammatory cytokines, i.e., IL-6, TNF-alpha, and GM-CSF, as well as negative immunoregulatory proteins, such as IL-10 and IL-1RA.

Adult↗
PubMed1999

Alterations in immune functions during normal aging and Alzheimer's disease.

It is thought that aging induces immune changes, which are related to the pathophysiology of Alzheimer's disease (DAT). In this study, the total number of leukocytes, white blood cell differentiation, mitogen-induced lymphocytic proliferation, neutrophil phagocytosis and superoxide release, and prostaglandin E2 (PGE2) production by mitogen-stimulated whole blood cultures were comparatively investigated between healthy adults (range 22-45 years) and healthy elderly volunteers (range 70-91 years), and between DAT patients (range 56-94 years) and age-matched control subjects. Healthy elderly volunteers showed significantly lower phytohemagglutinin (PHA)-induced lymphocyte proliferation and percentage and absolute number of basophils than young volunteers. In normal volunteers, there were significant and negative correlations between age and the number of basophils. Patients with DAT showed a trend toward significantly higher PHA-induced lymphocyte proliferation and significantly decreased percentage and absolute number of large unstained cells than healthy volunteers. In DAT patients, the total number of leukocytes and the percentage and number of neutrophils were positively correlated with age. All other immune-inflammatory variables were not significantly altered either by the aging process or DAT. The present study suggests that aging and DAT may differently affect some immune variables.

Adult↗
PubMed1999

Development of diagnostic reagents to differentiate between Mycobacterium bovis BCG vaccination and M. bovis infection in cattle.

In Great Britain a recent independent scientific review for the government has concluded that the development of a cattle vaccine against Mycobacterium bovis holds the best long-term prospect for tuberculosis control in British herds. A sine qua non for vaccination is the development of a complementary diagnostic test to differentiate between vaccinated animals and those infected with M. bovis so that test-and-slaughter-based control strategies can continue alongside vaccination. In order to assess the feasibility of developing a differential diagnostic test for a live vaccine, we chose M. bovis BCG Pasteur as a model system. Recombinant forms of antigens which are expressed in M. bovis but not, or only at low levels, in BCG Pasteur (ESAT-6, MPB64, MPB70, and MPB83) were produced. These reagents were tested either alone or in combination by using peripheral blood mononuclear cells from M. bovis-infected, BCG-vaccinated, and Mycobacterium avium-sensitized calves. All four antigens induced in vitro proliferation and gamma interferon responses only in M. bovis-infected animals. A cocktail composed of ESAT-6, MPB64, and MPB83 identified infected animals but not those vaccinated with BCG. In addition, promiscuous T-cell epitopes of ESAT-6, MPB64, and MPB83 were formulated into a peptide cocktail. In T-cell assays with this peptide cocktail, infected animals were identified with frequencies similar to those obtained in assays with the protein cocktail, while BCG-vaccinated or M. avium-sensitized animals did not respond. In summary, our results suggest that peptide and protein cocktails can be designed to discriminate between M. bovis infection and BCG vaccination.

Amino Acid Sequence↗