John Radcliffe Hospital

About: John Radcliffe Hospital is a healthcare organization based out in Oxford, Oxfordshire, United Kingdom. It is known for research contribution in the topics: Population & Antigen. The organization has 14491 authors who have published 23670 publications receiving 1459015 citations.

Effects of ras and von Hippel-Lindau (VHL) gene mutations on hypoxia-inducible factor (HIF)-1alpha, HIF-2alpha, and vascular endothelial growth factor expression and their regulation by the phosphatidylinositol 3'-kinase/Akt signaling pathway.

Abstract: Many oncogenes induce expression of vascular endothelial growth factor (VEGF), a key factor in tumor angiogenesis. Phosphatidylinositol 3'-kinase (PI3K)/Akt is a common signaling pathway for oncogenes and tumor suppressor genes and is involved in VEGF regulation. Because hypoxia is a major stimulus for VEGF production, we examined the effects of LY294002, a selective PI3K inhibitor, on hypoxia-inducible factor (HIF)-1alpha and HIF-2alpha expression and on endogenous VEGF responses to hypoxia. A panel of breast cancer cell lines reflecting the different genetic changes occurring in human breast cancer was analyzed. LY294002 inhibited HIF-1alpha induction and phosphorylation under hypoxia. However, HIF-2alpha expression was not affected. Basal and hypoxia-inducible VEGF expression was reduced at both mRNA and protein levels by 50%. V12-ras overexpression resulted in an increase in hypoxia-induced HIF-1alpha and HIF-2alpha expression. This effect was blocked by PI3K inhibitor, demonstrating one mechanism for ras synergy with hypoxia-mediated induction of genes. The decreased HIF-1alpha expression was not dependent on VHL interaction because a renal carcinoma cell line with VHL mutation and constitutive high HIF-1alpha expression also showed down-regulation of HIF-1alpha after treatment with LY294002. These results have implications for the use of PI3K inhibitors to inhibit synergistic effects of hypoxia with a wide range of common oncogenes.

Susceptibility to insulin dependent diabetes mellitus maps to a 4.1 kb segment of DNA spanning the insulin gene and associated VNTR.

Abstract: Recent studies have demonstrated that a locus at 11p15,5 confers susceptibility to insulin dependent diabetes mellitus (IDDM). This locus has been shown to lie within a 19 kb region. We present a detailed sequence comparison of the predominant haplotypes found in this region in a population of French Caucasian IDDM patients and controls. Identification of polymorphisms both associated and unassociated with IDDM has allowed us to define further the region of association to 4.1 kb. Ten polymorphisms within this region are in strong linkage disequilibrium with each other and extend across the insulin gene locus and the variable number tandem repeat (VNTR) situated immediately 5' to the insulin gene. These represent a set of candidate disease polymorphisms one or more of which may account for the susceptibility to IDDM.

The pattern and outcome of acute severe colitis

Abstract: Background: The prognosis of acute severe ulcerative colitis (ASC) influences therapeutic decisions, but data on prevalence or long-term outcome are few. Methods: A systematic review of all patients with UC diagnosed in Oxford was performed to assess the prevalence of ASC defined by Truelove and Witts' (TW) criteria and determine whether outcome is related to disease activity on admission, likelihood of recurrence and long-term prognosis. Results: 750 patients (median follow up 12.7 yr, range 0–648 mo) met inclusion criteria out of a total cohort of 1853 patients. 24.8% (186/750) had at least one admission for ASC (294 admissions in 186 patients). Overall, 12% (93/750) had a colectomy, compared to 39.8% (74/186) of patients with one or more episodes of ASC ( p < 0.0001) and 3.4% (19/564) in those with no admission. The colectomy rate on first admission (37/186, 19.9%) was lower than on the second or subsequent admissions (OR 2.35, 95% CI 1.33–4.14, p = 0.003), being 29.0%, 36.6%, 38.2% after two, three, or subsequent episodes respectively. It was 8.5% (11/129) if patients had one TW criterion in addition to ≥ 6 bloody bowel motions/day, compared to 31% (29/94) if two additional criteria were present and 48% (34/71) if three or more additional criteria were present ( p = 1.4 × 10− 5; OR 4.35, 95% CI 2.20–8.56 one criterion vs two or more). Conclusions: A quarter of all patients with ulcerative colitis experience at least one episode of ASC; 20% come to colectomy on first admission, but 40% after two admissions. The likelihood of colectomy is related to biological severity on admission.