Biomedical subjects
Publications and source records attributed to M Azizi.
Homozygous haemoglobin LeporeBoston disease is described in an Iranian 16-year-old boy presenting the clinical manifestations of BETA-thalassaemia major. The parents were related (cousins), and both carriers of Lepore trait. It seems that the symptoms are milder in this case than what reported before.
Investigations for renal artery stenosis have been greatly facilitated by advances in imaging techniques. Intravenous digital subtraction angiography is now performed in all patients with progressive, drug-resistant hypertension associated with aorto-iliac lesions or with renal impairment induced by angiotensin-converting enzyme inhibitors. Yet the finding of hypertension with renal artery stenosis is not enough to make the diagnosis of renovascular hypertension, this term being reserved to hypertension reversible by revascularization. The selection of patients who may benefit from revascularization rests on urography to explore the excretory and endocrine functions of the ischaemic kidney, as well as on scintigraphy and measurement of renin levels in renal veins before and after administration of captopril. The functional data are completed by vascular exploration which helps in evaluating the usefulness and safety of revascularization: repercussions of hypertension on target organs and extension of the vascular disease to other territories. Revascularization as first-line treatment consists of percutaneous transluminal dilatation; surgery must be reserved to difficult cases, such as arterial obliteration or failed dilatation.
A blockade of the hemodynamic and tissue effects of angiotensin II (Ang II) more complete than that presently achieved with usual daily doses of angiotensin coverting enzyme (ACE) inhibitors or type 1 Ang II receptor antagonists has potential advantages and risks. Therefore, it is worthwhile to investigate the biological and the hemodynamic effects of the simultaneous blockade of the renin-angiotensin system (RAS) at the two sites where it can be currently achieved, ACE and type 1 Ang II receptors. To investigate this issue, 2 double-blind randomized crossover studies were performed in a model of mild sodium depletion in normotensive volunteers. They ingested single oral doses of captopril 50 mg, losartan 50 mg, their combination or matched placebos, and in a second study, single oral doses of enalapril 10 mg, enalapril 20 mg and the combination of losartan 50 mg with enalapril 10 mg. The combination of captopril 50 mg and losartan 50 mg had additive effects on blood pressure fall and renin release in sodium-depleted normotensive subjects. When compared to enalapril 10 mg and the doubling of its dose, the combination of losartan 50 mg and enalapril 10 mg significantly increased both the area under the time curve of mean blood pressure fall and plasma active renin levels. It did not further decrease plasma aldosterone levels. The conclusion is that a more complete blockade of the RAS can be achieved by concomitant administration of a type 1 Ang II receptor antagonist and an ACE inhibitor.
BACKGROUND: Atherosclerotic renal artery stenosis (ARAS) is associated with progressive loss of renal function and is one of the most important causes of renal failure in the elderly. Current treatment includes restoration of the renal arterial lumen by endovascular stent placement. However, this treatment only affects damage caused by ARAS due to the stenosis and ensuing post-stenotic ischemia. ARAS patients have severe general vascular disease. Atherosclerosis and hypertension can also damage the kidney parenchyma causing renal failure. Medical treatment focuses on the latter. Lipid-lowering drugs (statins) could reduce renal failure progression and could reduce the overall high cardiovascular risk. The additional effect on preserving renal function of stent placement as compared to medical therapy alone is unknown. Therefore, the STAR-study aims to compare the effects of renal artery stent placement together with medication vs. medication alone on renal function in ARAS patients. METHOD: Patients with an ARAS of > or = 50% and renal failure (creatinine (Cr) clearance < 80 mL/min/1.73 m2) are randomly assigned to stent placement with medication or to medication alone. Medication consists of statins, anti-hypertensive drugs and antiplatelet therapy. Patients are followed for 2 yrs with extended follow-up to 5 yrs. The primary outcome of this study is a reduction in Cr clearance > 20% compared to baseline. This trial will include 140 patients.