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Biomedical subjects

M Saeed

Publications and source records attributed to M Saeed.

At least 163 records · Page 9Linked to original sources
PubMed1988

Deep venous thrombosis evaluation with limited-flip-angle, gradient-refocused MR imaging: preliminary experience.

Sixteen patients (17 lower extremities) were prospectively examined with venography and limited-flip-angle, gradient-refocused magnetic resonance (MR) imaging for the presence or absence of deep venous thrombosis. Thrombosed vessels showed decreased-to-absent signal intensity, while patent vessels had high signal intensity. In 16 of 17 extremities, MR images allowed accurate detection and localization of the thrombi found with venography. In the remaining extremity, MR imaging allowed correct identification of thrombus in the iliac and femoral veins but incorrectly demonstrated clot in the calf and popliteal veins. MR imaging with limited-flip-angle, gradient-refocused pulse sequences appears to be a sensitive, noninvasive means of detecting deep venous thrombosis.

Female↗
PubMed1988

Gastric adenocarcinoma: CT versus surgical staging.

Seventy-five patients with gastric carcinoma underwent preoperative staging with computed tomography (CT). In 14 patients, CT failed to demonstrate lymphadenopathy despite the presence of malignant lymph nodes at surgery. In 13 patients, CT demonstrated enlarged nodes, but no malignant involvement was found at surgery. Although spread to the pancreas was correctly predicted in three patients with lack of fat plane between tumor and pancreas, five patients lacking a fat plane had no invasion, whereas eight patients with an intact fat plane had invasion. Thirty-five patients (47%) were incorrectly staged with CT:23 (31%) were understaged and 12 (16%) were overstaged. CT does not accurately display the true extent of disease in patients with gastric carcinoma and therefore should not be used routinely for staging.

Adenocarcinoma↗
PubMed1988

Effect of nisoldipine on large coronary arteries in situ: inhibition of vasoconstriction induced by vasopressin.

The effects of nisoldipine on myocardial performance and large coronary artery diameter, resistance and cross-sectional area were studied in rabbit hearts in situ. Changes in mean internal diameter of coronary artery segments were visualized using color arteriography; changes were computer-calculated. Nisoldipine had a direct dilatory effect on large coronary arteries in situ and it attenuated the vasoconstriction induced by vasopressin. It shifted the dose-response curve of vasopressin to the right in a noncompetitive manner. Nisoldipine reduced the effect of vasopressin on maximum left ventricular dP/dt, mean aortic pressure, left ventricular end-systolic pressure and heart rate. The results demonstrate that nisoldipine is an effective dilator of large epicardial coronary arteries in situ and inhibits the vasoconstriction induced by vasopressin.

Animals↗
PubMed1988

Fibromuscular dysplasia of renal arteries: comparison of intravenous digital subtraction angiography with conventional angiography.

Intravenous digital subtraction angiography (IV-DSA) was compared with conventional arteriography (CA) in 14 patients with fibromuscular dysplasia (FMD) of at least one renal artery. IV-DSA identified 29 of the 34 renal arteries detected by CA. A diagnostic quality IV-DSA examination was obtained in 23 of 29 renal arteries (78%). In adequately imaged renal arteries, IV-DSA correctly identified 12 of 20 FMD renal arteries, misdiagnosed 8 FMD renal arteries as normal and correctly identified 3 normal renal arteries. These poor results, due to poor spatial resolution and subtraction artifacts inherent in the IV-DSA system, warrant careful interpretation of negative examinations and further evaluation of high risk patients.

Angiography↗
PubMed1988

Uncertain role of endothelium-derived relaxing factor in mesenteric arterioles of cats and rabbits.

Experiments were undertaken in the mesentery of anesthetized cats and rabbits to investigate whether the endothelium of resistance vessels mediates relaxation of arteriolar smooth muscle through the endothelium-derived relaxing factor(s) (EDRF). The microcirculation was visualized by transillumination using intravital microscopy and a Millikan camera. Pictures were obtained at a rate of 400 frames/second. Arteriolar mean diameter and surface area were computer calculated. The animals were divided in two groups. In one group of experiments, EDRF was inactivated by direct injection of hydroquinone (HQ) into the superior mesenteric artery and the second group served as control. Norepinephrine or vasopressin constricted while acetylcholine or Ca-ionophore A23187 dilated arterioles. Hydroquinone failed to inhibit arteriolar dilation in situ. The effect of HQ on the endothelium in situ was ascertained by bioassay of superior mesenteric artery strips. Our results cast doubt on the role of EDRF in the dilation of mesenteric arterioles in felines and rabbits.

Acetylcholine↗
PubMed1988

Birth asphyxia.

Explore the source record for details and available documents.

Apgar Score↗
PubMed1988

Effect of EDRF release from freshly harvested endothelial cells on the coronary circulation of the isolated working rabbit heart.

Vascular relaxation in rabbit aortic preparations by acetylcholine is endothelium-dependent. Because of the short half-life of the endothelium-derived relaxing factor(s) (EDRF), a constant source of this material is necessary to study its effect in perfused hearts or hearts in situ (reported half-life 6-50 sec). To investigate the effect of EDRF(s) on the large coronary arteries and the resistance vessels of the isolated working rabbit heart, freshly harvested porcine endothelial cells were used. The cells were stimulated with acetylcholine to produce EDRF(s). To extend the half-life of EDRF, superoxide dismutase was added to the cell suspension. Left atrial infusion of these cells increased coronary flow and reduced total coronary resistance. No significant effect on the diameter of the endothelium-deprived obtuse marginal coronary artery was noted. The vasoconstrictor effect on resistance vessels of topically applied histamine was significantly reduced during the infusion of activated endothelial cells. It can be concluded that EDRF(s) released from freshly harvested endothelial cells increases coronary flow and diminishes total coronary vascular resistance in the working heart. In this preparation coronary arterioles are more sensitive to EDRF(s) than large coronary arteries. EDRF may contribute to the regulation of regional myocardial flow.

Acetylcholine↗
PubMed1987

Inhibition of vasoactive agents by perfluorochemical emulsion.

Perfluorochemicals are widely used in clinical and experimental studies as volume expanders with high oxygen carrying capacity. We noticed that contractions of rabbit aortic strips, induced by norepinephrine, were inhibited in FC-43 emulsion as compared to Krebs-Henseleit solution (KH). To study this inhibition, a comparative evaluation was made of the contractile responses of norepinephrine, serotonin and histamine in FC-43 emulsion and KH. The effect of these agents was significantly diminished in FC-43 emulsion; concentration-response curves were shifted to the right and the maximum response was diminished. A search was made for the individual constituents of FC-43 responsible for diminution of contraction of vascular smooth muscle. After centrifugation of FC-43 emulsion, the supernatant caused a reduction of contractility and reduced EC50-values of norepinephrine to the same degree as the fully constituted emulsion. This excluded perfluorotributylamine, the oxygen carrying particles, as being responsible for this inhibition. When the detergent Pluronic F-68 was added to KH in concentrations equal to that in FC-43 emulsion, inhibition of contraction occurred and EC50-values increased. Contractions induced by norepinephrine were equally inhibited by the addition to KH of a volume expander, hydroxyethylstarch, in a concentration equal to that in FC-43 emulsion. It is concluded that FC-43 emulsion inhibits vasoactive agents and attenuates its pharmacologic effects on vascular smooth muscle. The fractions of FC-43 emulsion responsible for inhibiting the effect of vasoactive agents are Pluronic F-68 and hydroxyethylstarch.

Animals↗
PubMed1987

A relaxing factor released by phospholipase A2 in the absence of endothelium.

Phospholipase A2 (PLA2) produced slow dose dependent relaxation in intact and endothelium-deprived precontracted rabbit aortic strips. In endothelium-deprived preparations, relaxation induced by PLA2 is inhibited by hemoglobin, methylene blue and parabromophenacylbromide (PBPB), and is potentiated by superoxide dismutase (SOD). Indomethacin has no effect. Relaxation is accompanied by a rise in c-GMP. Phospholipase C causes a significant increase in tension, while Phospholipase D has no effects. In intact aortic strips PLA2 causes a biphasic response with no elevation in c-GMP. The results indicate several common features of the PLA2 released factor with endothelium-derived relaxing factor (EDRF). However, PLA2 induced relaxation is not dependent on endothelial cells. Apparently in addition to nitric oxide which may be the endothelium-derived relaxing factor, a second smooth muscle relaxing factor exists which is initiated by PLA2 and is independent of endothelium. The production of the PLA2 produced relaxation is dependent on its specific hydrolytic activity. We call this relaxing factor the phospholipid-derived relaxing factor (PDRF).

Animals↗
PubMed1987

The role of lysolecithin in the relaxation of vascular smooth muscle.

The effect of lysolecithin (lysophosphatidylcholine) on the relaxation of rabbit aortic strip closely resembled that produced by acetylcholine (ACh) which releases the endothelium-derived relaxing factor (EDRF). Relaxation induced by lysolecithin depended on the presence of endothelium and was inhibited by hemoglobin and methylene blue. It appeared to be mediated by the second messenger, c-GMP. Lysolecithin induced relaxation was slower but more persistent than that resulting from the endothelium-derived relaxing factor (EDRF) produced by acetylcholine (ACh). Like lysolecithin, Triton X-100, a non-ionic detergent, also preferentially relaxed aortic strips with intact endothelium. The results demonstrate the importance of phospholipids derived from cell membranes in vascular smooth muscle relaxation. Endothelium-derived relaxing factors appear as a group of heterogeneous substances.

Animals↗
PubMed1987

Digital intravenous subtraction angiography in the evaluation of reconstructed renal arteries.

Digital intravenous subtraction angiography (DISA) was used to evaluate 28 patients who had undergone renal artery reconstruction either as part of a renal transplant procedure or for treatment of renovascular hypertension. Satisfactory visualization of the renal artery was obtained in 26 cases, and the clinical questions were adequately answered in these cases. The findings included a variety of possible outcomes and demonstrate the adequacy of DISA as a means of evaluating the results of renal artery surgery. Technical and anatomic factors affecting the quality of the examination are discussed. The cases also illustrate the critical importance of thorough familiarity with the surgical procedures in general and of mutual discussion between surgeon and radiologist in optimizing the DISA examination in a given patient.

Adult↗
PubMed1987

Polar infarct in a transplanted kidney: cause of a pseudomass.

Ultrasonography has become fairly standard for assessing common complications of renal transplantation such as hydronephrosis, urinomas, and lymphoceles. Infarctions are a less common complication that may occur in the setting of transplant rejection. We report a case in which an apparent solid mass on sonography proved to represent normal residual renal parenchyma in a kidney with a small shrunken lower pole due to infarction.

Female↗
PubMed1987

The vasodilator effect of coronary vascular endothelium in situ: its inactivation by hydroquinone.

Studies were carried out to demonstrate the presence of the endothelium derived relaxing factor (EDRF) in coronary arteries in situ and the effect of hydroquinone on this factor. The studies revealed the presence of EDRF in coronary arteries of rabbit hearts remaining in situ. EDRF was inactivated by left atrial injection of hydroquinone. In situ constriction of coronary arteries by vasopressin was markedly increased following exposure to hydroquinone, and the dilatory response to acetylcholine was absent. The experiments confirm the presence of the endothelium derived relaxing factor in coronary arteries in situ and its inactivation by hydroquinone.

Animals↗
PubMed1987

Intravenous digital subtraction angiography in the evaluation of potential renal donors.

Of 65 surgically removed donor kidneys intravenous digital subtraction angiography demonstrated accurately the number of renal arteries in 58 (89 per cent). All accessory vessels missed at digital subtraction angiography were small and their presence did not interfere with successful transplantation in those donated. Of 50 surgically removed donor kidneys examined with conventional aortography only before the routine use of intravenous digital subtraction angiography the number of renal arteries was demonstrated accurately in 46 (92 per cent). Intravenous digital subtraction angiography offers advantages over conventional aortography, including most importantly the routine performance on an outpatient basis, and decreased film cost and examination time. Although the accuracy of conventional aortography (92 per cent) in detecting the number of renal arteries is slightly greater than that for intravenous digital subtraction angiography (89 per cent), the advantages of the digital examination justify its use as the initial examination for the potential renal donor. Conventional aortography can be reserved for use in patients with equivocal or technically inadequate digital examinations.

Angiography↗
PubMed1987

Transluminal angioplasty of venous stenoses in polytetrafluoroethylene vascular access grafts.

Since 1984, percutaneous transluminal angioplasty (PTA) utilizing high pressure balloon catheters has been used as an initial approach to restore patency of PTFE (polytetrafluoroethylene, GORE-TEX) hemodialysis vascular access grafts. Seventeen stenotic lesions detected by fistulogram underwent elective PTA. Twelve of these lesions were detected after thrombectomy and five were detected because of increased venous pressures during dialysis. Fourteen attempts at PTA were completely successful in restoring functional patency to the vascular graft. Three attempts were unsuccessful; two of these three grafts were subsequently repaired surgically. Venous stenoses that extended far greater than 6 cm were not considered for PTA. We conclude that PTA is a technique of promise in the non-surgical salvage of failing PTFE grafts. PTA can prolong the useful life of PTFE vascular access grafts and can be performed on an outpatient basis, eliminating the hospitalization that is usually required for surgical revision.

Adult↗
PubMed1987

Effect of a new phosphodiesterase type III inhibitor as a coronary vasodilator and positive inotropic agent.

Isolated rabbit coronary arteries, aortic strips, and a working rabbit heart preparation were used to assess the positive inotropic and vasodilator effects of a newly developed positive inotropic compound, CI 914. The substance had a relaxing effect on histamine preconstricted coronary arteries and aortic strips. At concentrations of 10(-4) mol.litre-1 the relaxing effect on the coronary arteries was significant only at a histamine concentration of 3 x 10(-4) mol.litre-1 (p less than 0.01) whereas at a concentration of 10(-3) mol.litre-1 the relaxing effect was significant at histamine concentrations of from 3 x 10(-5) mol.litre-1 to 3 x 10(-4) mol.litre-1. Aortic strips were more sensitive to the relaxing effect of CI 914, which was significant with 10(-4) mol.litre-1 at histamine concentrations of 3 x 10(-6) to 3 x 10(-4) (p less than 0.05 to p less than 0.01). In the isolated working heart preparation topically sprayed histamine significantly increased total and large coronary artery resistances (p less than 0.001 and p less than .01). This effect was significantly reduced (p less than 0.01 and p less than 0.02) when CI 914 10(-4) mol.litre-1 was present in the perfusion fluid. These findings show that the phosphodiesterase inhibitor CI 914, a positive inotropic agent, induces vasodilation in isolated coronary arteries and aortic strips of the rabbit and reduces the constriction of coronary arteries induced by histamine in the isolated working rabbit heart preparation.

Animals↗
PubMed1987

Percutaneous drainage of pelvic lymphatic fluid collections in the renal transplant patient.

Seventeen renal transplant patients with pelvic lymphatic fluid collections were treated with percutaneous drainage. Eleven of 16 patients with lymphoceles (69%) were successfully managed without surgery, although seven of these patients required repeat catheter insertions, and three patients developed local infections. The patient with an ovarian cystadenoma was treated with surgery. The mean duration of catheter insertion was ten days for initial drainage and 16 days for repeat drainage. Elevated serum creatinines decreased in 14 of the patients with lymphoceles (88%), including all five patients without pelvocaliectasis, but never returned to baseline in six instances. This observation may reflect the inadequate therapy of frequently encountered concurrent renal parenchymal abnormalities (rejection, cyclosporine toxicity, acute tubular necrosis). While percutaneous management of lymphoceles is technically easy and usually ultimately effective, the interventional radiologist should be prepared for long duration of catheter insertions, repeat interventions, and variable clinical courses. Differentiation of lymphoceles from other fluid collections, such as cystic ovarian neoplasms, may be difficult.

Adult↗