Leicester Royal Infirmary

About: Leicester Royal Infirmary is a healthcare organization based out in Leicester, United Kingdom. It is known for research contribution in the topics: Population & Carotid endarterectomy. The organization has 5300 authors who have published 6204 publications receiving 208464 citations.

Free radicals and antioxidants in cardiovascular disease

Abstract: Several lines of evidence suggest that free radical-mediated oxidative damage to lipoproteins may be an important factor predisposing them to uptake into the vascular wall. This has led to interest in the factors that determine the susceptibility of lipoproteins to oxidation and their relationship to the development of coronary heart disease. Of these factors, the lipoprotein content of natural antioxidant vitamins such as vitamin E, and beta-carotene have aroused particular interest. Studies in animal models of atherosclerosis suggest that natural and synthetic antioxidants can retard the development of atheroma. Epidemiological comparisons between populations and studies within populations also support the contention that high plasma levels or dietary intake of natural antioxidant vitamins may protect against the development of coronary disease in man. Prospective randomized controlled trials of antioxidants in high risk groups are underway to test whether the theoretical promise of a beneficial role for antioxidants in coronary heart disease prevention will be fufilled.

Vitamin D and systemic cancer: is this relevant to malignant melanoma?

Abstract: 1,25-dihydroxyvitamin D3[1,25(OH)2D3] is a well-known potent regulator of cell growth and differentiation and there is recent evidence of an effect on cell death, tumour invasion and angiogenesis, which makes it a candidate agent for cancer regulation. The classical synthetic pathway of 1,25(OH)2D3 involves 25- and 1 alpha-hydroxylation of vitamin D3, in the liver and kidney, respectively, of absorbed or skin-synthesized vitamin D3. There is recent focus on the importance in growth control of local metabolism of 1,25(OH)2D3, which is a function of local tissue synthetic hydroxylases and particularly the principal catabolizing enzyme, 24-hydroxylase. The classical signalling pathway of 1,25(OH)2D3 employs the vitamin D nuclear receptor (VDR), which is a transcription factor for 1,25(OH)2D3 target genes. Effects of this pathway include inhibition of cellular growth and invasion. Cytoplasmic signalling pathways are increasingly being recognized, which similarly may regulate growth and differentiation but also apoptosis. 1,25(OH)2D3 has a major inhibitory effect on the G1/S checkpoint of the cell cycle by upregulating the cyclin dependent kinase inhibitors p27 and p21, and by inhibiting cyclin D1. Indirect mechanisms include upregulation of transforming growth factor-beta and downregulation of the epidermal growth factor receptor. 1,25(OH)2D3 may induce apoptosis either indirectly through effects on the insulin-like growth receptor and tumour necrosis factor-alpha or more directly via the Bcl-2 family system, the ceramide pathway, the death receptors (e.g. Fas) and the stress-activated protein kinase pathways (Jun N terminal kinase and p38). Inhibition of tumour invasion and metastasis potential has been demonstrated and mechanisms include inhibition of serine proteinases, metalloproteinases and angiogenesis. The lines of evidence for an effect of vitamin D3 in systemic cancer are the laboratory demonstration of relevant effects on cellular growth, differentiation, apoptosis, malignant cell invasion and metastasis; epidemiological findings of an association of the occurrence and outcome of cancers with derangements of vitamin D3/1,25(OH)2D3 and the association of functional polymorphisms of the VDR with the occurrence of certain cancers. In addition, vitamin D3 analogues are being developed as cancer chemotherapy agents. There is accumulating evidence that the vitamin D3/1,25(OH)2D3/VDR axis is similarly important in malignant melanoma (MM). MM cells express the VDR, and the antiproliferative and prodifferentiation effects of 1,25(OH)2D3 have been shown in cultured melanocytes, MM cells and MM xenografts. Recently, an inhibitory effect on the spread of MM cells has been demonstrated, low serum levels of 1,25(OH)2D3 have been reported in MM patients and the VDR polymorphisms have been shown to be associated with both the occurrence and outcome of MM. The relationship between solar irradiation and MM is more complex than for the systemic cancers. As in other cancers, there is evidence of a protective effect of vitamin D3 in MM, but ultraviolet radiation, which is a principal source of vitamin D3, is mutagenic. Further work is necessary on the influence of serum vitamin D3 levels on the occurrence and prognosis of MM, the effects of sun protection measures on serum vitamin D3 levels in temperate climates and epidemiological studies on geographical factors and skin type on the prognosis of MM. Meanwhile, it would seem mandatory to ensure an adequate vitamin D3 status if sun exposure were seriously curtailed, certainly in relation to carcinoma of breast, prostate and colon and probably also MM.

Isotropic resolution diffusion tensor imaging with whole brain acquisition in a clinically acceptable time.

Abstract: Our objective was to develop a diffusion tensor MR imaging pulse sequence that allows whole brain coverage with isotropic resolution within a clinically acceptable time. A single-shot, cardiac-gated MR pulse sequence, optimized for measuring the diffusion tensor in human brain, was developed to provide whole-brain coverage with isotropic (2.5 x 2.5 x 2.5 mm) spatial resolution, within a total imaging time of approximately 15 min. The diffusion tensor was computed for each voxel in the whole volume and the data processed for visualization in three orthogonal planes. Anisotropy data were further visualized using a maximum-intensity projection algorithm. Finally, reconstruction of fiber-tract trajectories i.e., "tractography" was performed. Images obtained with this pulse sequence provide clear delineation of individual white matter tracts, from the most superior cortical regions down to the cerebellum and brain stem. Because the data are acquired with isotropic resolution, they can be reformatted in any plane and the sequence can therefore be used, in general, for macroscopic neurological or psychiatric neuroimaging investigations. The 3D visualization afforded by maximum intensity projection imaging and tractography provided easy visualization of individual white matter fasciculi, which may be important sites of neuropathological degeneration or abnormal brain development. This study has shown that it is possible to obtain robust, high quality diffusion tensor MR data at 1.5 Tesla with isotropic resolution (2.5 x 2.5 x 2.5 mm) from the whole brain within a sufficiently short imaging time that it may be incorporated into clinical imaging protocols.

Growth differentiation factor-15 as a prognostic marker in patients with acute myocardial infarction.

Abstract: Aims Our aim was to assess the long-term prognostic value of growth differentiation factor-15 (GDF-15) in patients post-acute myocardial infarction (AMI). Growth differentiation factor-15 is a member of the transforming growth factor β family. Growth differentiation factor-15 is expressed in the myocardium and upregulated due to ‘stress’ and has been shown to have antiapoptotic actions. Its role in the cardiovascular system however is not well defined. We were interested to see if GDF-15 could provide long-term prognostic value in post-AMI patients. We compared GDF-15 with N-terminal pro-B-type natriuretic peptide (NT-proBNP). Methods and results We recruited 1142 consecutive post-AMI patients [820 men, median (range) age 67 (24–97) years] in a prospective study with a follow-up period of 505 (range 1–2837) days. Growth differentiation factor-15 levels increased with increasing Killip class ( P < 0.001) and were correlated with NT-proBNP ( r = 0.47, P < 0.001). Using a multivariable Cox proportional hazards model, log GDF-15 (HR 1.77), log NT-proBNP (HR 2.06), age (HR 1.03) Killip class above 1, (HR 1.62), use of beta-blockers (HR 0.54) and past history of MI (HR 1.44) were significant independent predictors of death or heart failure (HF). Predictors of death were log NT-proBNP, log GDF-15, age, eGFR, past history of MI, use of beta-blockers, and use of ACE inhibitors or angiotensin receptor blockers. The C-statistic for GDF-15 for predicting death or HF at 1 year was 0.73 (95% CI: 0.70–0.76, P < 0.001) and was 0.76 (95% CI: 0.70–0.80, P < 0.001) for NT-proBNP. Combining these markers yielded an AUC of 0.81 (95% CI: 0.77–0.85), which exceeded that of GDF-15 ( P < 0.001) and NT-proBNP ( P = 0.004) alone. The Kaplan–Meier analysis revealed that those patients with above median GDF-15 and NT-proBNP had the highest event rate for death and HF (log rank 50.22, P < 0.001). Conclusion Growth differentiation factor-15 is a new marker for predicting death and HF in post-AMI patients. GDF-15 provides prognostic information over and above clinical factors and the established biomarker NT-proBNP. Combined levels of GDF-15 with NT-proBNP can identify a high-risk group of patients.

World leaders' usage of Twitter in response to the COVID-19 pandemic: a content analysis.

Abstract: Background It is crucial that world leaders mount effective public health measures in response to COVID-19. Twitter may represent a powerful tool to help achieve this. Here, we explore the role of Twitter as used by Group of Seven (G7) world leaders in response to COVID-19. Methods This was a qualitative study with content analysis. Inclusion criteria were as follows: viral tweets from G7 world leaders, attracting a minimum of 500 'likes'; keywords 'COVID-19' or 'coronavirus'; search dates 17 November 2019 to 17 March 2020. We performed content analysis to categorize tweets into appropriate themes and analyzed associated Twitter data. Results Eight out of nine (88.9%) G7 world leaders had verified and active Twitter accounts, with a total following of 85.7 million users. Out of a total 203 viral tweets, 166 (82.8%) were classified as 'Informative', of which 48 (28.6%) had weblinks to government-based sources, while 19 (9.4%) were 'Morale-boosting' and 14 (6.9%) were 'Political'. Numbers of followers and viral tweets were not strictly related. Conclusions Twitter may represent a powerful tool for world leaders to rapidly communicate public health information with citizens. We would urge general caution when using Twitter for health information, with a preference for tweets containing official government-based information sources.