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Biomedical subjects

A Simon

Publications and source records attributed to A Simon.

587 records · Page 33Linked to original sources
PubMedDate not supplied

Antihypertensive and vasodilating effects of acute medroxalol, a new beta-blocker with beta-2-adrenergic receptor stimulation.

The effects of medroxalol, a new beta-blocking drug, were simultaneously studied on the brachial artery, the arterioles and the veins of the forearm in 15 patients with mild to moderate essential hypertension after administration of a single oral dose of 200 mg, by means of pulsed Doppler velocimetry of the brachial artery and strain gauge mercury-in silastic plethysmography of the forearm. In addition the systolic time intervals including preejection period (PEP) and left ventricular time (LVET) were also measured after drug administration. Acute oral medroxalol produced a rapid and significant decrease in systolic and diastolic blood pressure and in heart rate. Concomitantly a significant increase was observed in brachial artery diameter (p less than 0.05), blood velocity and flow (p less than 0.01); forearm vascular resistance decreased (p less than 0.001) but forearm venous tone was unchanged. Lastly medroxalol prolonged PEP but shortened LVET corrected for heart rate. These results demonstrate a rapid antihypertensive action of a single dose of medroxalol with a dilation of the arteries but not of the veins of the forearm and a discrepant effect on the systolic time intervals.

Adult↗
PubMedDate not supplied

MCF-7 cell cycle arrested at G1 through ursolic acid, and increased reduction of tetrazolium salts.

The effect of ursolic acid on the proliferation of MCF-7 human breast tumor cells was studied. During investigations of the anti-proliferative effects of this triterpene, we observed a clear difference between MTT colorimetric assay and direct cell counting, particularly 24 h after drug treatment. The MTT assay showed a stimulation of formazan production in the first 24 h exposure of cells to drug. The maximum stimulation was obtained with 15 and 20 microM of ursolic acid (about 30 - 40% of increase with respect to control); however, the number of cells was not increased as revealed by direct cell counting. Ursolic acid is a potent inhibitor of MCF-7 cell proliferation. This triterpene exhibits both cytostatic and cytotoxic activity. It exerts an early cytostatic effect at G1 followed by cell death. Cell cycle analysis is performed by propidium iodide staining and flow cytometry technique. These results suggest that alterations in cell cycle phase redistribution of MCF-7 human breast cancer, by ursolic acid, may significantly influence MTT reduction to formazan.

Antineoplastic Agents, Phytogenic↗
PubMedDate not supplied

[Diabetic macroangiopathy in humans].

The detection of early atherosclerosis, accelerated by the presence of diabetes mellitus, is of major importance for improving the prediction and the prevention of subsequent clinical events. Three markers of atherosclerosis can be detected non invasively: arterial wall thickening, coronary calcification and arterial wall stiffening. Intima-media thickness can be measured by B-mode ultrasonography in common carotid and femoral arteries. Increased intima-media thickness has been found to be associated with both insulin-dependent and non insulin-dependent diabetes. Such thickening might be partly of atherogenic nature but may also be due to a non-atherogenic process such as medial hypertrophy possibly related to insulin effects. Coronary calcification, an anatomic marker of coronary atheroma, is detected radiographically by fluoroscopy or ultrafast computed tomography. Cross-sectional studies of asymptomatic high-risk populations have found independent associations between diabetes and the presence and amount of coronary calcium deposit. The mechanisms by which diabetes promotes coronary calcium deposit are unknown, but mineralization proteins, such as osteopontin and its genetic expression, might be implicated in the calcinosis process. Arterial wall stiffening, a marker of sclerosis, detected by pulse wave velocity measurement or by determination of arterial wall motion using an echotracking device, has been found to be associated with diabetes in several case-control and transverse studies. The mechanisms of such association may involve the effect of glycoregulation of bioelastomers in the arterial wall. The detection of early atherosclerosis in diabetic patients may be clinically relevant by helping to improve the prediction of vascular risk, the justification to treat, and the evaluation of the efficacy of antidiabetic treatment on the vessels.

Arteries↗