Biomedical subjects

G Radford-Smith

Publications and source records attributed to G Radford-Smith.

11 recordsLinked to original sources

PubMed2006

Comparison of the efficacy and safety of Eudragit-L-coated mesalazine tablets with ethylcellulose-coated mesalazine tablets in patients with mild to moderately active ulcerative colitis.

BACKGROUND: There are no comparative studies of coated mesalazine. AIM: To compare the efficacy and tolerability of Eudragit-L- and ethylcellulose-coated mesalazine tablets in patients with mild to moderately active ulcerative colitis. METHODS: A double-blind, double-dummy, randomized parallel group trial was performed across 18 centres in Australia, and 20 in Eastern Europe. Patients were treated with 3 g mesalazine for 8 weeks with the primary efficacy end point being clinical remission. RESULTS: Of 215 patients, 69% achieved clinical remission in both treatment groups (P < 0.001; chi-square test) with no differences in frequency of adverse events. In the Australian cohort (n = 63), the Eudragit-L group had a higher remission rate (73% vs. 36%) and responded 13 days faster, compared with those in the European group (67% vs. 84%, and 2 days respectively). No clear reasons for differences in treatment responses were identified. CONCLUSIONS: Eudragit-L and ethylcellulose-coated mesalazine tablets are well tolerated and equally effective in achieving remission in mild-moderately active ulcerative colitis over 8 weeks.

Administration, Oral↗

PubMed2006

CDP571, a humanized monoclonal antibody to tumour necrosis factor-alpha, for steroid-dependent Crohn's disease: a randomized, double-blind, placebo-controlled trial.

BACKGROUND: More than 50% of patients with Crohn's disease become either steroid resistant or dependent. Accordingly, development of new treatments for steroid-dependent Crohn's disease is a research priority. AIM: To evaluate CDP571, a humanized antibody to tumour necrosis factor-alpha, for the treatment of steroid-dependent Crohn's disease. METHODS: Patients with steroid-dependent Crohn's disease (n = 271) were enrolled in a 36-week, double-blind, placebo-controlled trial. Steroid dependence was defined as use of prednisolone or prednisone (15-40 mg/day) or budesonide (9 mg/day) for > or =8 weeks, a previous failed attempt to decrease or discontinue steroids within 8 weeks of screening, and a Crohn's Disease Activity Index score of < or =150 points. Patients were randomized to receive intravenous CDP571 10 mg/kg or placebo 8-weekly through to week 32. Steroids were then tapered using a defined schedule. The primary efficacy endpoint was the percentage of patients with steroid sparing, defined as discontinuation of steroid therapy without a disease flare (Crohn's Disease Activity Index score > or =220 points) at week 36. RESULTS: Steroid sparing occurred in 53 of 181 (29.3%) CDP571 patients and 33 of 90 (36.7%) placebo patients (P = 0.24). Adverse events occurred at similar frequencies in both treatment groups. CONCLUSIONS: CDP571 was ineffective for sparing steroids in patients with steroid-dependent Crohn's disease. CDP571 was well tolerated.

Adult↗

PubMed2004

CDP571, a humanised monoclonal antibody to tumour necrosis factor alpha, for moderate to severe Crohn's disease: a randomised, double blind, placebo controlled trial.

BACKGROUND: Targeting tumour necrosis factor alpha (TNF-alpha) has demonstrated efficacy in Crohn's disease. AIM: To evaluate CDP571, a humanised antibody to TNF-alpha, for treating active Crohn's disease. PATIENTS: A total of 396 patients with moderate to severe Crohn's disease. METHODS: In a 28 week, randomised, double blind, placebo controlled trial, patients received intravenous CDP571 (10 mg/kg) or placebo every eight weeks to week 24. The primary outcome measure was clinical response (a decrease in the Crohn's disease activity index (CDAI) to > or =100 points or remission (CDAI score < or =150 points)) at week 28. A secondary outcome measure was clinical response (using the same definition) at week 2. RESULTS: Clinical response occurred at week 28 in 80/263 (30.4%) CDP571 patients and 31/132 (23.5%) placebo patients (p = 0.102). Clinical response at week 2 occurred in 90/263 (34.2%) CDP571 patients and 28/132 (21.2%) placebo patients (p = 0.011). Post hoc exploratory subgroup analysis of 159 patients with baseline C reactive protein (CRP) > or =10 mg/l demonstrated significant differences between CDP571 and placebo in clinical response rates at weeks 2 (CDP571, 50/101 (49.5%); placebo, 9/58 (15.5%); p<0.001) and 28 (CDP571, 29/101 (28.7%); placebo, 7/58 (12.1%); p = 0.018). Adverse events occurred at similar frequencies in both treatment groups. CONCLUSIONS: CDP571 is modestly effective for short but not long term treatment of unselected patients with moderate to severe Crohn's disease. The clinical relevance of this short term effect is unclear. Post hoc analysis suggests both short and long term efficacy of CDP571 in patients with elevated baseline CRP (> or =10 mg/l). CDP571 is well tolerated.

Adult↗

PubMed2002

A comparison of 13 guinea pig and human anti-tissue transglutaminase antibody ELISA kits.

AIMS: Tissue transglutaminase (tTG) is a major autoantigen recognised by IgA anti-endomysial antibodies (IgA EMA). Enzyme linked immunosorbent assays (ELISA) for IgA anti-tissue transglutaminase antibodies (IgA tTG) have therefore been developed as an alternative serological screening test to IgA EMA for coeliac disease (CD). The use of human tTG (h-tTG), as opposed to guinea pig liver tTG (gpl-tTG), in these assays has been reported to produce superior results. This study compared 13 commercial IgA tTG ELISA kits to ascertain their performance characteristics in the diagnosis of CD in patients with biopsy confirmed disease compared with controls. All patients and controls were adults aged 21 years or older. METHODS: Sera from the following groups of patients were tested in each kit: (1) 49 patients with CD confirmed on small bowel biopsies (all IgA EMA positive); (2) 34 patients with small bowel biopsies that were not consistent with CD; and (3) 30 patients with biopsy confirmed inflammatory bowel disease. All controls were negative for IgA EMA and were not IgA deficient. Sensitivities and specificities were determined using both the manufacturers' recommended cut off points and receiver operating characteristic (ROC) analysis derived decision thresholds. The area under the curve (AUC) for each ROC plot was also calculated and compared between kits. RESULTS: In general, the h-tTG based IgA tTG ELISA kits demonstrated superior performance (especially specificity) compared with the gpl-tTG based kits, although 100% sensitivity and specificity (comparable to the IgA EMA assay) was obtained in only one recombinant h-tTG based kit. CONCLUSIONS: The use of h-tTG in IgA tTG ELISA kits is generally, but not universally, associated with superior performance. Factors other than antigen source are important in determining kit performance.

Adult↗

PubMed1998

Reciprocal relationship between the tumor suppressors p53 and BAX in primary colorectal cancers.

Though most colorectal cancers show allelic losses, a subset of colorectal cancers (microsatellite instability or MSI-positive cancers) develop numerous small insertion and deletion mutations in repetitive DNA. Some of these sequences occur in coding regions of cancer related genes which, when targeted by frameshift mutations, produce truncations in their protein product. Such a gene is the proapoptotic tumor suppressor, BAX, mutated by frameshifts within a polyG sequence in approximately 50% of MSI-positive colorectal cancers. BAX is directly transactivated by p53, a gene commonly mutated in colorectal cancers but not often in MSI-positive lesions. Here we sought to characterize the relationship between BAX and p53 by simultaneously analysing a selected series of 65 colorectal tumors for mutations in the entire coding regions of both genes. The tumors comprised 19 MSI-high, 12 MSI-low and 34 MSI-null cancers. Eight of 19 MSI-high sporadic colorectal cancers (42%) contained insertions and deletions at the polyG tract in the BAX gene. In addition, three somatic BAX missense mutations were identified in two tumors. A single missense mutation was detected in an MSI-high tumor that also contained a frameshift microdeletion, and two missense mutations were identified in an MSI-null tumor wild-type for p53. p53 mutations were detected in 5/12 MSI-low tumors (42%) and 12/34 MSI-null tumors (35%). Of significance, no p53 mutations were detected in MSI-high tumors. This study demonstrates that a reciprocal relationship exists between p53 and BAX in sporadic colorectal cancers, and further supports the hypothesis that MSI-low tumors are biologically similar to MSI-null tumors.

Amino Acid Sequence↗

PubMed1998

Morphology of sporadic colorectal cancer with DNA replication errors.

BACKGROUND: Up to 15% of colorectal cancers are characterised by DNA microsatellite instability (MIN), shown by the presence of DNA replication errors (RERs). AIMS: To identify pathological features that are discriminating for colorectal cancer (CRC) showing extensive MIN. SUBJECTS: A prospective series of 303 patients with CRC and no family history of either familial adenomatous polyposis or hereditary non-polyposis colorectal cancer. METHODS: DNA was extracted from fresh tissue samples and the presence of MIN was studied at nine loci that included TGF beta RII, IGFIIR, and BAX. The 61 cases showing RERs were compared with 63 RER negative cases with respect to a comprehensive set of clinical and pathological variables. Predictive utility of the variables was tested by decision tree analysis. RESULTS: Twenty seven patients with CRC showed extensive RERs (three loci or more) (RER+) and 34 had limited RERs only (28 = one locus; 6 = two loci) (RER+/-), yielding a bimodal distribution. RER+ cancers differed from RER- and RER+/-) cases. Tumour type (adenocarcinoma, mucinous carcinoma, and undifferentiated carcinoma) (p = 0.001), tumour infiltrating lymphocytes (p = 0.001), and anatomical site (p = 0.001) were the most significant of the discriminating variables. Algorithms developed by decision tree analysis allowed cases to be assigned to RER+ versus RER- and +/- status with a global sensitivity of 81.5%, specificity of 96%, and overall accuracy of 93%. CONCLUSIONS: Pathological examination of CRC allows assignment of RER+ status; assignment is specific and relatively sensitive. Conversely RER- and RER+/- CRC are indistinguishable.

Adenocarcinoma↗

PubMed1997

Ulcerative colitis: an immunological disease?

Ulcerative colitis is an inflammatory disease of the large intestine of unknown aetiology. The nature of the inflammatory infiltrate together with the response to corticosteroids suggests that an abnormal immune response is at work. The key question of whether the immune system is responding to an abnormal breach in the mucosa due to another primary abnormality or whether the primary defect lies within the immune response itself has not been answered. Thus far, it is clear that both T and B cell compartments are involved in the persistence of inflammation but the initial interactions that take place in the mucosa in terms of antigen processing and presentation have not been adequately investigated. Those critical steps and potential defects that push T cells and B cells into a heightened state of activation need to be identified.

Animals↗

PubMed1996

Cytokine gene transcription of human colonic intraepithelial lymphocytes costimulated with epithelial cells bearing HLA-DR and its inhibition by 5-aminosalicylic acid.

The objectives of this study were to activate human colonic intraepithelial lymphocytes at the transcriptional level with HLA-DR+ human colonic epithelial cell line (HT29) in synergy with CD3 monoclonal antibody and to investigate the molecular mechanism for the therapeutic effects of 5-aminosalicylic acid. Lymphocytes were isolated by a mechanical method from resected colon of 22 cases and then cocultured on 10 ng/ml CD3mAb immobilized plates with HT29 which had been induced to express MHC class II molecules by interferon gamma. Flow cytometry analysis suggested that the lymphocyte population had a CD4/CD8 ratio similar to that observed in intact tissue sections and that there was no HT29 contamination of the lymphocytes isolated again from cocultured cells. The activation of intraepithelial lymphocytes showed the gene transcription of interferon gamma and tumor necrosis factor alpha, as measured by means of the reverse-transcriptase polymerase chain reaction, and this activation was antagonized by 5-aminosalicylic acid. Thus, epithelial cells bearing HLA-DR are capable of enhancing CD3-induced activation of human colonic intraepithelial lymphocytes and subject to inhibition by 5-aminosalicylic acid, the active moiety of salicylates used in inflammatory bowel disease.

Actins↗

PubMed1996

Cytokines and inflammatory bowel disease.

Cytokines play an important role in the pathology of inflammatory bowel disease by determining the nature of the mucosal immune response. One way of establishing whether CD and UC are causally related to a defect in the host immune response is to look for polymorphisms that are over-represented in these populations. This is being carried out at great pace both for the cytokine genes and for some other immune response genes. A number of gene expression studies have established that those cytokines produced by activated macrophages such as IL-1, IL-6 and TNF are significantly elevated in both diseases. Differences between the two diseases are less clear, and, where they have been found, they probably reflect the accuracy and sensitivity of quantification. The picture is less clear for the T-cell-derived cytokines, which are generally expressed at a lower copy number in intestinal tissue compared to the monokines. For Crohn's disease, the TH1 cytokines IL-2 and IFN may be abnormally elevated or decreased. In contrast, the TH1/TH2 profile in UC is not significantly different from normal controls. Further work is required to confirm these findings.

Colitis, Ulcerative↗

PubMed1995

Appendectomy and tonsillectomy in patients with inflammatory bowel disease.

Recent reports of reduced appendectomy rates in patients with ulcerative colitis have not distinguished between primary appendectomy (surgery for appendicitis) and incidental appendectomy (removal of the appendix for other reasons). In the present case control study, we examined the frequency of primary appendectomy in subjects with ulcerative colitis (n = 197) and Crohn's disease (n = 117) compared to a control group of dermatology outpatients (n = 243). A reduced rate of primary appendectomy was found in the ulcerative colitis group (adjusted odds ratio 0.20, 95% confidence intervals 0.070-0.53, p < 0.0005) but not in the Crohn's disease patients (adjusted odds ratio 0.93, 95% confidence intervals 0.39-2.18, p = NS). These data suggest that appendicitis occurs less commonly than would be expected in individuals who develop ulcerative colitis. Environmental or immunoregulatory factors may be responsible. Tonsillectomy rates were also examined in each study group, but no overall differences were found between patients with inflammatory bowel disease and controls.

Adult↗

PubMed1994

Cytokine gene expression in HIV-infected intestinal mucosa.

OBJECTIVE: Cytokine dysregulation has been implicated in AIDS pathogenesis and the gastrointestinal tract, containing approximately 40% of the body's lymphoid tissue, is likely to act both as a reservoir of viral infection and a site for immune dysregulation. In this study evidence of cytokine dysregulation in intestinal mucosa has been sought using the reverse transcriptase polymerase chain reaction (RT-PCR) to amplify cytokine mRNA. METHODS: RT-PCR was performed on intestinal biopsies obtained from 50 HIV-infected patients and 31 controls. Tissue was obtained at diagnostic endoscopy and total RNA extracted using an RNAzol technique. Following RT, cDNA was amplified using primers specific for beta-actin, interleukin (IL)-1 beta, tumour necrosis factor (TNF)-alpha, interferon (IFN)-gamma, IL-2, IL-4, IL-10 and IL-13. RESULTS: There was a significant increase in the expression of the proinflammatory cytokines IL-1 beta and IFN-gamma in the HIV-infected compared with the control small intestinal samples (P < 0.01). IL-10 was significantly reduced in the respective groups' large intestine (P < 0.02). The expression of IL-2 was also reduced in both the small and large intestinal HIV samples although this was not significant. IL-13 mRNA was only detected in one control patient. CONCLUSIONS: Dysregulation of cytokine gene expression occurs in the intestinal mucosa of patients with HIV infection and is characterized by increased expression of proinflammatory cytokine mRNA. Further studies are needed to localize the cellular origin of such dysregulation and to quantify the degree of abnormality.

Base Sequence↗