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Results for “BLOOD VESSELS, PERIPHERAL”

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At least 37 records · Page 2Linked to original sources
PubMed1991

[Non-invasive diagnosis of lesions of peripheral blood vessels in patients with diabetes mellitus].

Clinical examination of 51 diabetes mellitus patients with the disease running a severe, moderate and light course included ultrasound dopplerography to measure arterial and venous pressure on the malleolus and photoplethysmography to evaluate arterial pressure in the great toe. There appeared a relationship between the disease severity and venous pressure, toe pressure index, pressure gradient malleolus--toe. The closest correlation was with the venous pressure. At late stages of diabetic angiopathy calcinosis of the arterial wall distorts real value of malleolar systolic pressure necessitating multimodality investigation of peripheral vessels in diabetic patients.

Aged↗
PubMed1996

[2-D-time-of-flight MR angiography of the peripheral blood vessels. Experimental and clinical studies on value of this method in arterial occlusive diseases].

PURPOSE: A retrospective study was performed in 70 patients with peripheral vascular disease who underwent MR angiography of the lower extremity. MATERIAL AND METHODS: MR angiography was performed with a 2-D-TOF sequence including a travelling presaturation to suppress the venous signal. Postprocessing images were obtained with the MIP algorithm. The MRA results were compared with conventional or digital angiography in all patients. RESULTS: Only 19 stenoses out of 31 which showed a degree of stenosis between 30 and 99% could be visualised by MR angiography. 9 stenoses were correctly classified by MRA. In 9 cases the degree of stenosis was overestimated, in one case it was underestimated. All 56 occlusions were correctly detected. 12 severe stenoses diagnosed with conventional angiography were graded as occlusions with MR angiography. CONCLUSIONS: MR angiography cannot be accepted in preoperative staging of patients with peripheral vascular disease. The postoperative examination seems to be a practical noninvasive alternative.

Algorithms↗
PubMed1989

Differential vasoreactivity to the thromboxane A2 mimic U-46619 of collateral and normal peripheral blood vessels in situ perfused rat hindquarters.

In situ perfusion of rat hindquarters was performed through both iliac arteries. Perfusion pressures were measured concomitantly in the normal vascular bed and in the ligation-induced collateral bed of the left and right hindleg, respectively. An increased vaso-constrictive response of the collateral versus normal blood vessels was found after bolus injections of increasing concentrations of the thromboxane A2 (TXA2) mimic U-46619. This increased reactivity was related to a difference in vascular structure and in receptor-mediated sensitivity. The vasoconstrictive effect of U-46619 was dose-dependently inhibited by the combined TXA2 synthetase inhibitor-TXA2/prostaglandin endoperoxide (PGH2) receptor antagonist ridogrel and the single TXA2/PGH2 receptor antagonist sulotroban. Selective blockade of alpha 1-, alpha 2-, beta 1-beta 2- and S2-receptors, cyclooxygenase inhibition, TXA2 synthesis inhibition, amine depletion and amine uptake blockade had no influence on the vasoconstrictive action of U-46619. Ca2+ entry blockade by flunarizine and nifedipine significantly reduced the vasoconstriction. This study shows that (1) rat peripheral collaterals in relation to normal arterial blood vessels are significantly more reactive to TXA2; (2) the vasoconstrictive effect of U-46619 is mediated predominantly by TXA2/PGH2 receptors; (3) the activation of these receptors elicits indirectly transmembrane Ca2+ entry to trigger vasoconstriction.

15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗
PubMedDate not supplied

An ultrastructural study of blood vessels in peripheral nerves of leprosy patients: blood vessels in peripheral nerves.

Ultrathin sections of nerves of tuberculoid and lepromatous leprosy were examined in an electron microscope for changes in endoneural blood vessels. In the tuberculoid nerves, hypertrophy of endothelial cells was the most prominent feature. This was to such an extent that the lumen of blood vessel was often closed. Endoneural blood vessels showed multilayers separated by collagen and ground substances. In contrast, in the lepromatous nerves, there was no hypertrophy of endothelial cells in the blood vessels and the lumen of the vessels was open. M. leprae were seen within the endothelial cells and these organisms were intact and probably viable. These observations suggest a possible involvement of endoneural blood vessels which may contribute to nerve damage in leprosy.

Endothelium, Vascular↗
PubMed1997

[Contrast medium enhanced MR angiography of peripheral blood vessels].

Currently 2D time-of-flight MR angiography (MRA) is most commonly used for the evaluation of the extremities. The major limitation is their susceptibility to signal loss from intravoxel phase dispersion. This leads to overestimation in the grading of stenoses. Further difficulties are motion artifacts and the limited spatial resolution. Phase-contrast MRA is increasingly used. However, further studies are required to verify its diagnostic potential. MRA technology continues to advance rapidly. Stronger gradient fields, shorter echo times and high resolution surface coils are developed. Contrast medium can be applied under standardized conditions with MR compatible power injectors. In phantom studies, the contrast-enhanced gradient echo sequences show reduced phase dispersion, resulting in an improved grading of stenoses. Initial patient studies underline these findings. Contrast-enhanced MR angiography has the potential to replace invasive arteriography in the evaluation of peripheral arterial vessels in the near future.

Arteriosclerosis↗
PubMed1994

[MR angiography of peripheral blood vessels].

MR angiography (MRA) of the extremities is in its infancy. The potential appears to be great, but several problems have to be solved before MRA can routinely be used as the definitive diagnostic procedure. MRA can detect arterial stenoses, occlusions, and determine their length. The degree of stenosis, however, is overestimated. Although the spatial resolution of MRA allows depiction of the tibial vessels, evaluation of their major branches is necessary for distal bypass surgery. The postoperative examination of patients with bypasses seems to be a practical alternative with regard to the established angiography techniques. At present, MRA is cost-effective, but not as readily available as conventional angiography. MRA technology continues to advance rapidly. With improved technology, judicious use, and appropriate patient selection, in the future MRA should assume a role in the evaluation of peripheral arterial occlusive disease.

Arterial Occlusive Diseases↗
PubMed1987

Actions of calcium antagonists on pre- and postjunctional effects of neuropeptide Y on human peripheral blood vessels in vitro.

The mechanisms underlying the contractile effects of neuropeptide Y (NPY) in relation to those of noradrenaline (NA) on small human blood vessels were studied in vitro. NPY caused contractions of mesenteric veins, renal and skeletal muscle arteries but not of mesenteric arteries. NPY was about 5- to 10-fold more potent than NA. The maximal contractile responses to NPY (5 X 10(-7) M) were 38 +/- 4, 37 +/- 8 and 95 +/- 16% of the response evoked by NA 10(-5) M in the mesenteric vein, renal and skeletal muscle arteries respectively. The NPY effects were resistant to adrenoceptor antagonists. The calcium antagonist nifedipine reduced the effect of NA but not the contractile response to NPY on mesenteric veins. Nifedipine and felodipine reduced the contractile response to both NA and NPY on renal and skeletal muscle arteries. In contrast to the contractile effects of K+, the responses to NPY and NA were largely uninfluenced by changes in extracellular Ca2+ concentrations. Nifedipine still inhibited the NPY contractions in a Ca2+-free medium while high extracellular Ca2+ (7.5 mM) partly reduced the nifedipine effect. NPY reduced the nerve stimulation-evoked [3H]NA overflow from the mesenteric veins via a nifedipine resistant mechanism. The stable analogue alpha, beta-methylene adenosine triphosphate (mATP) was more potent than ATP and had nifedipine-sensitive contractile effects similar to those of NA on the human blood vessels without influencing the nerve-evoked [3H]NA efflux. In conclusion, NPY exerts a potent nifedipine-sensitive vasoconstrictor activity, especially on human skeletal muscle arteries in vitro, although the influx of extracellular calcium may not be a crucial mechanism. The NPY-induced contractions of mesenteric veins and the inhibition of nerve-evoked [3H]NA efflux seem to be mediated via nifedipine resistant messenger systems.

Arteries↗
PubMed1975

Vascular resistance in peripheral blood vessels at normotension and at local orthostatic hypertension in healty humans.

The effect of changes in orthostatic pressure on vascular resistance in subcutaneous adipose tissue was examined in the forearm at normal tension and in the leg at local orthostatic hypertension in three normal subjects. Blood flow in subcutaneous tissue was measured by the local xenon-133 washout technique. Changes in orthostatic pressure were achieved by postural changes of the extremity. At levels above the heart where venous pressure is constant, there was autoregulation of blood flow over a wider arterial blood pressure range in leg than in forearm. When transmural pressure increased 25 mm Hg or more vascular resistance increased about 50 per cent in the dependent forearm and 300 per cent in the dependent leg. The effect of ischemia on vascular resistance was investigated in cutaneous tissue of hand and foot by means of the 131I-Antipyrine initial slope technique. Vascular resistance after maximum dilatation achieved after 20, 30, and 35 min of ischemia was less in vessels of the hand than in vessels of the foot. Thus, adaptive structural changes of vessels subjected to increased blood pressure are present in cutaneous and subcutaneous adipose tissues in normal subjects.

Adipose Tissue↗