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Biomedical subjects

A Whelan

Publications and source records attributed to A Whelan.

At least 37 records · Page 2Linked to original sources
PubMed1999

Identification of common epitopes on gliadin, enterocytes, and calreticulin recognised by antigliadin antibodies of patients with coeliac disease.

BACKGROUND: Sera of patients with coeliac disease, containing IgA and IgG antigliadin antibodies (AGA) and various IgA autoantibodies, react with isolated enterocytes. AGA cross react with enterocyte antigens, one of which has been identified as calreticulin. AIMS: To characterise the antigenic structures of gliadin, enterocytes, and calreticulin recognised by AGA from patients with active coeliac disease. METHODS: AGA were isolated from sera of nine patients by affinity chromatography and tested by competitive ELISA using 40 alpha-gliadin synthetic dodecapeptides (A1-F6). RESULTS: Reactivity of gliadin with all purified AGA tested was inhibited by peptide A4 at the N-terminal region; by C2, C3, and D4 at the central region; and by F3 and F4 at the C-terminal region of the gliadin molecule. AGA cross reactivity with enterocytes was inhibited by peptides A4, D1-D4, and F6 and with calreticulin by peptides A4, D3, and D4. As dominant epitopes AGA of coeliac patients recognise similar structures corresponding to peptides A4, D3, D4, and F6 present on gliadin, enterocytes, and calreticulin. Substitution of glutamine in the A4 peptide by glutamic acid caused loss of inhibitory capacity. Shortening of peptide A4 on the N-terminal by three amino acids increased its inhibitory effect. CONCLUSIONS: AGA of patients with coeliac disease react with similar structures on gliadin and potential autoantigens on enterocytes.

Adult↗
PubMed1998

The inflammatory response system and the availability of plasma tryptophan in patients with primary sleep disorders and major depression.

BACKGROUND: It is now well established that major depression is accompanied by an immune-inflammatory system response and that indicators of the latter are inversely correlated with lower availability of plasma tryptophan in depression. Inflammation and infection can alter sleep architecture, whereas sleep disturbances can impair immune functions. AIMS AND METHODS: The aims of the present study were to examine: (i) immune-inflammatory markers, i.e. serum interleukin-6 (IL-6), IL-8, IL-6 receptor (IL-6R), IL-1R antagonist (IL-1RA), gp130, and prostaglandin E2 (PGE2) production by mitogen-stimulated whole blood and the availability of plasma tryptophan in patients with primary sleep disorders, major depression and healthy volunteers; and (ii) the relationships between the availability of tryptophan and indicators of the immune-inflammatory response system. RESULTS: Mitogen-stimulated release of PGE2, and serum IL-6 and IL-8, were significantly increased in both depressed and sleep disordered patients compared to normal controls. Serum IL-1RA was significantly higher in depressed patients than in normal controls. Patients with depression and sleep disorders had a significantly lower availability of tryptophan than normal controls. There were significant and inverse relationships between the availability of plasma tryptophan and serum IL-1RA, IL-6 and IL-8. CONCLUSIONS: The results suggest that (i) there is an activation of the immune-inflammatory response system in primary sleep disorders and depression; and (ii) the decreased availability of plasma tryptophan may be related to the inflammatory system response.

Adult↗
PubMed1998

Promoting successful breast feeding among women with a low income.

OBJECTIVE: To identify those factors which promote or discourage successful breast feeding in a sample of women with a low income. DESIGN: Qualitative research using in-depth, semi-structured interviews. SAMPLE: All women with a low income who were identified as having breast fed their latest baby at least once and who had delivered at a district general hospital in the south west of England from 17 September 1996 to 5 February 1997. FINDINGS: Three behavioural areas which determined whether or not women with a low income continued to breast feed were identified: individual and social environmental, baby and midwifery practice factors. In terms of individual and social environmental factors those women who continued to breast feed were more likely to have: positive attitudes; realistic expectations; greater levels of self-esteem; a supportive mother/friend; a partner who was not against breast feeding; and the ability to cope with the perceived temporary social isolation. In terms of baby factors those women who continued to breast feed had babies who were more likely to: have three- or four-hourly feeds; be perceived as a contented baby; and have gained weight. And finally, in terms of midwifery practice factors, those women who continued to breast feed were more likely to have: not been separated from their baby; not been given supplementary or complementary feeds; received good advice, especially with regard to positioning the baby at the breast; had greater continuity of midwifery input; had sufficient quality time with a midwife; and had the opportunity to solve problems with a community midwife's help. IMPLICATIONS FOR PRACTICE: Midwifery practice can be improved to promote successful breast feeding among women with a low income by: 1) creating realistic expectations and increasing women's confidence/desire to succeed in breast feeding; 2) providing good quality advice and support to mothers of newborn babies, particularly with regard to positioning the baby at the breast; 3) improving social-support networks available to breast-feeding mothers, perhaps through educating grandmothers (or partners) in breast-feeding matters.

Adolescent↗
PubMed1998

Correlation of platelet Fc gammaRIIA polymorphism in refractory idiopathic (immune) thrombocytopenic purpura.

Fc gammaRIIA, a low affinity receptor for IgG, is a polymorphic molecule: Fc gammaRIIA-HH131, Fc gammaRIIA-HR131 and Fc gammaRIIA-RR131. This polymorphism influences the efficiency of the receptor to bind with IgG2. Recent reports on altered distribution amongst individuals with heparin-induced thrombocytopenia (HIT) prompted us to examine the Fc gammaRIIA polymorphism in a cohort of patients with refractory idiopathic (immune) thrombocytopenic purpura (ITP), in whom severe disease had required them to undergo splenectomy. 29 post splenectomy ITP individuals and 61 normal controls were investigated. Polymerase chain reaction (PCR) and a Southern blotting technique were used to determine the Fc gammaRII polymorphism. Although the distribution of the allotypes of Fc gammaRIIA in the control population was similar to that found in other European studies of Caucasian populations (15 (25%) HH131; 35 (57%) HR131; 11 (18%) RR131), the patient group was skewed towards the RR131 allotype which has least efficiency for IgG2 binding (3 (10%) HH131; 12 (42%) HR131; 14 (48%) RR131; P<0.005). These findings suggest that Fc gammaRIIA polymorphisms may be implicated in the pathophysiology of ITP or may be responsible for modulating the immune response in this heterogeneous autoimmune disease.

Adolescent↗
PubMed1998

Endomysial antibody detection using human umbilical cord tissue as substrate: reactivity of cells in Wharton's jelly.

The measurement of immunoglobulin A (IgA) endomysial antibodies is now established as an important diagnostic test in gluten-sensitive disease. Monkey oesophagus is the commonly used tissue substrate, but it has been proposed that human umbilical cord tissue may be a suitable alternative for antibody detection. In this study, we report a modified method of examining endomysial antibody reactivity with cord tissue. This involves examination of antibody reactivity with cells in Wharton's jelly, and with umbilical cord blood vessel. A total of 370 patients being investigated for coeliac disease were studied and this diagnosis was established in 42. Endomysial antibodies were found in all 42 using umbilical cord tissue, and the test results were confirmed with monkey oesophagus substrate. In three of the remaining 328 non-coeliacs, a false-positive endomysial antibody test was noted and small intestine histology was normal in these patients. All positive sera were found to react with cells in Wharton's jelly, and reticular staining of blood vessels was also present. Examination for immunofluorescence in both Wharton's jelly and blood vessel components of cord tissue greatly simplified test interpretation.

Adolescent↗
PubMed1998

Diagnosis of gluten-sensitive enteropathy: is exclusive reliance on histology appropriate?

OBJECTIVE: Coeliac disease is a prevalent disorder but frequently remains undiagnosed because of varied modes of clinical presentation. In this study, methods for the detection of coeliac disease were evaluated in a clinical practice setting. METHODS: Small intestinal histology, IgA anti-endomysial and IgG anti-gliadin antibody tests were performed on 441 unselected, consecutive patients under investigation for small intestinal disease. Response to treatment and other clinical events were monitored over the ensuing years. RESULTS: Untreated coeliac disease was diagnosed in 97 patients and was excluded in 344. At clinical presentation, the endomysial antibody test was positive in 84 of the 97 untreated coeliac patients (sensitivity 87%) and negative in 340 of the 344 non-coeliac patients (specificity 99%). A typical histological lesion was found in 83 of the 97 coeliac patients (sensitivity 86%) but was absent in all 344 non-coeliacs (specificity 100%). The sensitivity of the gliadin antibody test was 69% and the specificity was 71%. CONCLUSIONS: In unselected patients attending a gastroenterology clinic, small bowel histology and endomysial antibody serology show similar predictive value in the diagnosis of coeliac disease. These results emphasize that a combination of clinical, histological and serological criteria are required for effective diagnosis of this disorder. Exclusive reliance on histology or serology will result in failure to make a diagnosis in a significant proportion of patients.

Adolescent↗
PubMed1997

Endomysium: autoantigen in coeliac disease.

In coeliac disease, dietary exposure to gluten is associated with an autoimmune response to gastrointestinal antigens, including endomysium. Measurement of autoantibodies to endomysium is a highly specific and sensitive method of diagnosing coeliac disease. Analysis of the interaction between gluten and endomysium should provide a critical insight into the pathogenesis of this condition.

Autoantibodies↗
PubMed1996

Human umbilical vein endothelial cells: a new easily available source of endomysial antigens.

OBJECTIVE: To evaluate human umbilical vein endothelial cells (HUVEC) as an alternative source of endomysial antigen (EmAg) and to assess their suitability for the detection of endomysial antibodies (EmA) in coeliac disease (CD). METHODS: HUVEC were reacted on glass slides with patient sera and examined by fluorescent microscopy. Flow cytometry was used to determine whether the EmAg was expressed on the surface of the cells or was intracellular. Absorption studies were used to confirm the specificity of results. RESULTS: The data presented here show that HUVEC contain an intracellular antigen that binds to immunoglobulin A (IgA) from patients with active CD. Correlation studies showed that HUVEC antibodies were present in the sera of all patients that contained EmA and reticulin IgA antibodies whereas reticulin antibodies were only present in 24 of the 31 patients who were either EmA or HUVEC positive. All of the sera tested which were negative for EmA were also negative for HUVEC antibodies. Ten patients with Crohn's disease and 10 patients with ulcerative colitis were negative for HUVEC or EmA reactivity, as were 16 control subjects attending the gastroenterology clinic with non-specific symptoms and normal small intestinal biopsies. CONCLUSIONS: These findings suggest that the antigen found in HUVEC is antigenically similar to that found in reticulin and endomysium and that all three antigens may be the same. In contrast to the monkey oesophagus, HUVEC offer an easily available antigen for the serological diagnosis of coeliac disease.

Antibodies, Anti-Idiotypic↗
PubMed1996

Increased expression of Fc gamma receptors on neutrophils and monocytes may reflect ongoing bacterial infection.

The Fc gammaR receptors for IgG, Fc gammaRI, Fc gammaRII and Fc gammaRIII were measured on neutrophils and monocytes from 36 patients suspected of systemic infection. These results were compared with 30 blood donor controls to assess the level of expression as an early indicator of bacterial infection. Fc gammaRI expression on neutrophils was found to be significantly increased from patients with systemic or localised infections, when compared to non-infected patient group, i.e., patients with no cultural evidence of bacterial infections, (p=0.02, p=0.04) or normal controls (p<0.0001, p=0.0005). Fc gammaRI expression on monocytes was also significantly increased in both of the infected groups compared to normal controls (p<0.0001, p=0.001); however, no significant difference could be seen when compared with the non-infected patients. Fc gammaRIII was found to be significantly increased on a subset of monocytes in patients with systemic or localised infections compared to the non-infected group (p=0.009, p=0.006) and compared to the normal controls (p=0.009, p=0.003). Infections caused by gram-negative bacilli induced a higher Fc gammaR response than infection with either streptococci or staphylococci. These data suggest that the measurement of Fc gammaRI on neutrophils and Fc gammaRIII on monocytes may be a useful rapid indicator of bacterial infection.

Bacterial Infections↗
PubMed1996

Increased numbers of CD5+ B cells and T cell receptor (TCR) gamma delta+ T cells are associated with younger age of onset in rheumatoid arthritis (RA).

Patients presenting with RA before the age of 45 years (younger onset) are known to have more aggressive disease compared with patients presenting after the age of 65 years (older onset). Coordinated expansion of circulating CD5+ B cell and TCR gamma delta+ T cell levels has been reported in patients with RA. This study assesses the peripheral blood levels of these two cell types in RA patients with younger and older onset of disease. CD5+ B cell levels were significantly elevated in the younger onset RA group (26.6+/-4.5%) compared with the older onset RA group (14.2+/-1.2%; P<0.01). TCR gamma delta+ T cell levels were also significantly raised in the young patients (4.0+/-0.9%) compared with elderly patients (1.6+/-0.2%; P<0.01). T cell levels (CD3+) were similar in both groups (young 66.4+/-3.3%; old 74.3+/-3.4% (mean+/-s.e.m.); NS). Total B cell levels (CD19+) were also similar in these groups (7.7+/-0.7% versus 8.9+/-1.8%; NS). A significant positive correlation was observed between the CD5+ B and TCR gamma delta+ T cell types in the patients (r=0.72, P<0.05). Compared with age-matched normal controls, the younger onset patients had similar CD5+ B cell and TCR gamma delta+ T cell levels to the elderly controls (CD5+ B cells 30.2+/-3.0%; TCR gamma delta+ T cells 3.0+/-0.8%). Conversely, older onset RA patients had CD5+ B cell levels similar to the young controls (12.3+/-1.9%). Spontaneous in vitro synthesis of immunoglobulins (IgM, IgA and IgG) and rheumatoid factors (IgM and IgA isotypes) were not significantly different in both patient groups. The coordinate expansion of circulating CD5+ B cells and gamma delta+ T cells seen in patients with RA presenting before 45 years of age and not after 65 years of age may suggest a potential role for these cells in more aggressive disease states.

Adult↗
PubMed1996

Secretion of the mycobacterial 19-kilodalton protein by Escherichia coli, a novel method for the purification of recombinant mycobacterial antigens.

We have reported previously (R.G. Hewinson and W.P. Russell, J. Gen. Microbiol. 139:1253-1259, 1993) the secretion by Escherichia coli of a recombinant form of the immunogenic protein MPB70 of Mycobacterium bovis when the protein is translated from its native initiation codon. N-terminal sequence analysis of the purified protein revealed that the signal peptide of MPB70 was cleaved by an endopeptidase of E. coli at the same cleavage site as reported for the protein in M. bovis. Since both the B- and T-cell antigenicities of the purified recombinant protein were similar to that of the native protein, the 19-kDa antigen of M. bovis was used as a model to test whether the signal peptide of MPB70 could direct the secretion of heterologous proteins in E. coli and whether antigen produced in this way retained antigenicity superior to that of recombinant protein produced as a fusion to glutathione-S-transferase. A chimeric protein was produced in which the signal peptide of MPB70 was fused to the 19-kDa antigen of M. bovis at amino acid residue 23. This chimeric protein was found to be secreted into the periplasm and culture medium of recombinant E. coli, and the signal peptide was cleaved by an endopeptidase of E. coli during secretion. Secretion of the 19-kDa antigen facilitated purification of the antigen by two-stage preparative electrophoresis which gave yields of 2.5 mg of purified, soluble 19-kDa antigen from 2.5 g (wet weight) of E. coli. Antigen purified in this way retained both B- and T-cell antigenicities. Moreover, the nonspecific mitogenic activity of the purified 19-kDa antigen was low, while the magnitude of the T-cell response induced by the purified antigen was considerably higher than that observed with purified antigen produced as a fusion protein with glutathione-S-transferase.

Amino Acid Sequence↗
PubMed1996

Beta-2-microglobulin, neopterin and monocyte Fc gamma receptors in opportunistic infections of HIV-positive patients.

The aim of this study was to examine serum and cellular markers of immune activation in HIV-positive (HIV+) patients with and without current opportunistic infections. Fc gamma receptor (Fc gamma R) expression on monocytes, serum neopterin and beta-2-microglobulin were studied. Thirty HIV+ patients (grouped according to Centers for Disease Control (CDC) classification) were studied and compared with 27 normal blood donor controls. HIV+ patients were further separated into three groups: 2 (CDC II), 3 (CDC III/IV without infections) and 4 (CDC III/IV with current infections). Eleven of the patients had current opportunistic infections. Results indicate that beta-microglobulin, neopterin, fc gamma RI, Fc gamma RII and Fc gamma III were significantly increased in HIV+ patients compared to controls. Further analysis of the data using Tukey-Kramer all pairwise comparison revealed that for beta-2-microglobulin the mean values for patients in groups 2, 3 and 4 were significantly different (P < 0.0001). Serum neopterin levels and the percentage of CD14+14+ monocytes expressing Fc gamma RIII showed significant differences in the mean values of group 2 and group 4; similarly, for CD4+ lymphocyte counts group 2 and group 4 were significantly different. These results indicated that beta-2-microglobulin, neopterin and CD14+ monocyte Fc gamma RIII are increased particularly in HIV+ patients with current opportunistic infections while CD4+ lymphocyte counts are reduced. The results suggest that these markers, particularly beta-2-microglobulin, could be useful indicators of the inflammatory process associated with opportunistic infection at later stages of disease where other laboratory markers may be atypical.

AIDS-Related Opportunistic Infections↗
PubMed1995

Role of charge in the radioprotection of E. coli by thiols.

The role of net charge (zeta) of thiols in their ability to radioprotect cells has been investigated in a glutathione (GSH)-deficient strain of E. coli. This strain, 7, is deficient in the enzyme gamma-glutamylcysteine synthetase and allows the effects of added low molecular weight thiols to be studied. Using the gas explosion system it is possible to measure the chemical repair of the free-radical precursors of lethal lesions by thiols in intact cells. The first-order chemical repair rate in strain 7 is 280 s-1 in comparison with 1100 s-1 in the wild-type strain 1157. From the measured difference in the intracellular concentration of GSH between the wild-type and the mutant, this gives a second-order repair rate, kr, of 1.23 +/- 0.3 x 10(5) dm3mol-1s-1. Measurement of intracellular thiol levels after addition of various low molecular weight thiols showed that uptake was rapid, leading to stable thiol levels within 1 min. The ratios of the intracellular to extracellular concentrations (Cin/Cout) were 0.74 for 3-mercaptopropionic acid (zeta = -1), 0.56 for 2-mercaptoethanol (zeta = 0), 1.47 for cysteamine (zeta = +1) and 1.04 for WR1065 (zeta = +2). The kr's for these thiols were 1.3 +/- 0.5 x 10(5) dm3mol-1s-1 for 30-mercaptopropionic acid, 3.3 +/- 1.6 x 10(5) dm3mol-1s-1 for 2-mercaptoethanol, 3.9 +/- 1.1 x 10(5) dm3mol-1s-1 for cysteamine and 2.7 +/- 1.1 x 10(6) dm3mol-1s-1 for WR1065. These are lower and increase less with charge than previously published values for chemical repair in isolated pBR322 DNA, probably because of the association of nucleoproteins and polyamines with the cellular DNA of E. coli. However, the approximate three-fold increase in kr per unit increase in zeta shows that the counter-ion condensation and co-ion depletion are important in determining the effectiveness of charged thiols in the radioprotection of E. coli.

DNA Repair↗
PubMed1995

Neuroproliferation in the mucosa is a feature of coeliac disease and Crohn's disease.

The pathogenesis of villous damage in coeliac disease is unknown. Change to the delicate neuromuscular core may be significant and this study stained various categories of coeliac disease and controls with neuron-specific enolase (NSE) to examine neurofilaments in the mucosa. The amount of NSE staining was evaluated using computer image analysis. The first part of the study compared coeliac disease with Crohn's disease, carcinoma, and biopsy specimens from normal subjects. There was increased NSE staining in both the coeliac disease and Crohn's disease cases but not in carcinomas or normal controls. This difference was statistically significant. The average value for the coeliac disease patients was 50% higher than that of Crohn's disease patients. The second part of the study compared treated coeliac disease with untreated coeliac disease. Treated coeliac disease cases had normal amounts of NSE staining, which were the same as normal controls. These findings suggest that neuroproliferation is a feature of coeliac disease and Crohn's disease. Both share a common feature--namely chronic inflammation--which has been occasionally associated with neuroproliferation. The fact that neuroproliferation resolves with treatment is further evidence for its association with chronic inflammation. The extra neuroproliferation seen in coeliac disease compared with Crohn's disease may contribute to the architectural abnormalities seen in coeliac disease.

Celiac Disease↗
PubMed1994

KP-1: not a specific marker. Staining of 137 sarcomas, 48 lymphomas, 28 carcinomas, 7 malignant melanomas and 8 cystosarcoma phyllodes.

This study documents the reactions of the monoclonal antibody KP-1, which detects histiocytes in paraffin sections, with 137 sarcomas, 48 lymphomas, 28 carcinomas, 7 malignant melanomas and 8 cystosarcoma phyllodes. The soft tissue sarcomas had been previously immunophenotyped. Positive staining was obtained in all categories of sarcoma except clear-cell sarcomas. Most categories of sarcoma showed staining in less than 10% of tumour cells although a minority of leiomyosarcomas showed more extensive staining. Five of 7 malignant melanomas were also positive while all lymphomas and carcinomas were negative. We conclude that KP-1 positivity is not helpful in supporting the histiocytic origin of a tumour and is of limited value in the differential diagnosis of soft tissue sarcomas or their separation from other categories of malignancy.

Antigens, CD↗
PubMed1994

Synovial tissue macrophages and joint erosion in rheumatoid arthritis.

OBJECTIVES: To analyse the mononuclear cell populations in synovial membrane biopsies obtained before treatment from patients with rheumatoid arthritis (RA) and to correlate the findings with the degree of joint damage occurring over one year. METHODS: Multiple needle biopsy specimens were obtained from inflamed knee joints on entry to the study. The tissue samples were examined using immunohistochemical techniques. The degree of joint damage was estimated using the Larsen radiological index. RESULTS: Twelve patients were studied. It was observed that there was a significant correlation between the number of synovial tissue macrophages and the degree of joint erosion over one year (r = 0.66; p = 0.04). The synovial lining layer contained large numbers of macrophages and the cellularity of the lining layer correlated significantly with the number of macrophages infiltrating the sublining areas (r = 0.65; p = 0.01). Finally, the cellularity of the lining layer correlated with the synovial fluid levels of interleukin-6 (r = 0.66; p = 0.04). The radiological course did not correlate with infiltrating T or B lymphocyte populations, but did correlate with other previously identified indicators of the clinical course, including a high index of disease activity and IgA rheumatoid factors levels. CONCLUSION: This study suggests that synovial tissue macrophages play a critical role in the pathogenesis of joint erosion in RA.

Adult↗