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Retinal vessel diameter, which is an important parameter in blood flow measurement, is affected by pulsation during the cardiac cycle and by vasomotion. This project studied these changes by analysing three monochromatic fundus photographs taken in eight arbitrary parts of the cardiac cycle of 10 healthy subjects. It was found that the venous diameter(More)
BACKGROUND Diffuse myocardial fibrosis (DMF) is important in cardiovascular disease, however until recently could only be assessed by invasive biopsy. We hypothesised that DMF measured by T1 mapping is elevated in isolated systemic hypertension. METHODS In a study of well-controlled hypertensive patients from a specialist tertiary centre, 46 hypertensive(More)
The effect of the carbonic anhydrase inhibitor, acetazolamide, on the retinal circulation was studied in 10 healthy volunteers. Acetazolamide was administered intravenously at a dose of 500 mg. Retinal blood flow was determined from red cell velocity using laser Doppler velocimetry and vessel diameter measurement using computerised digital image analysis of(More)
Autosomal dominant inheritance of thoracic aortic aneurysms and dissections occurs in subjects with Marfan syndrome, which results from mutations in the FBN1 gene on chromosome 15. A second chromosomal locus on 3p24-25 has been identified for a Marfan-like condition with thoracic aortic aneurysms. We describe here 6 families with multiple members with(More)
Accurate determination of retinal vessel width measurement is important in the study of the haemodynamic changes that accompany various physiological and pathological states. Currently the width at the half height of the transmittance and densitometry profiles are used as a measure of retinal vessel width. A consistent phenomenon of two 'kick points' on the(More)
Several mechanisms are implicated in the pathogenesis of diabetic retinopathy. They include biochemical, hemodynamic, and hormonal factors, all of which have an important role in the development of diabetic retinopathy. These factors are not independent of each other, but rather they interact and together are responsible for the well-known lesions of(More)
BACKGROUND Mutations in genes coding for sarcomeric proteins cause hypertrophic cardiomyopathy. Subtle abnormalities of the myocardium may be present in mutation carriers without left ventricular hypertrophy (G+LVH-) but are difficult to quantify. Fractal analysis has been used to define trabeculae in left ventricular noncompaction and to identify normal(More)
BACKGROUND Sarcomere protein mutations in hypertrophic cardiomyopathy induce subtle cardiac structural changes before the development of left ventricular hypertrophy (LVH). We have proposed that myocardial crypts are part of this phenotype and independently associated with the presence of sarcomere gene mutations. We tested this hypothesis in genetic(More)
Since the retinal vessels have no sympathetic innervation, blood flow in response to raised blood pressure is dependent on autoregulation. To determine the effect of hypertension on retinal haemodynamics and the autoregulatory capacity of the retinal circulation under conditions of normoglycaemia and hyperglycaemia, retinal blood flow was measured before(More)