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Biomedical subjects

W Feindel

Publications and source records attributed to W Feindel.

107 records · Page 6Linked to original sources
PubMed1967

Intracarotid fluorescein angiography: a new method for examination of the epicerebral circulation in man.

Patterns of blood flow were examined in the surface vessels of the surgically exposed brain by intracarotid injection of 1% fluorescein and rapid serial photographs timed by a photo-cell signal. Matching colour filters were used for black and white or Ektachrome film.As developed in cats and monkeys, and applied in five patients during craniotomy, the technique gave a picture of flow patterns in the pial and cortical vascular bed, demonstrating "water-shed" areas bordering major arterial territories, laminar flow in veins, and, in particular, the details of filling and clearing in the fine pial vessels, the superficial cortical capillary bed and in the vascular beds of tumours.Since these features are rendered in finer detail and sharper contrast than by standard x-ray angiography, the method affords a new means of more adequately examining the epicerebral circulation in man during craniotomy for a variety of lesions.

Animals↗
PubMedDate not supplied

Effects of hypercapnia on enhancement of decreased perfusion flow in non-infarcted brain tissues.

The effects of hypercapnia on enhancement of reduced cerebral perfusion were re-evaluated in areas of ischemia produced by occlusion of the canine middle cerebral artery. Perfusion was measured by 85Kr (beta-ray) and 133Xe (gamma-ray) clearances, fluorescein angiography and diameter measurement of arteries. Between 45 and 55 mm Hg of PaCO2 rCBF measured with both isotopes increased significantly. When PaCO2 was elevated above 55 mm Hg, there was a remarkable dissociation in the rCBF measured by both isotopes. Cortical blood flow measured by 85Kr clearance decreased and, conversely, rCBF measured by 133Xe continued to increase. Arteries of less than 50 mu in diameter in areas of ischemia dilated significantly during hypercapnia. At PaCO2 above 65 mm Hg, progressive sub-pial hemorrhage and extravasation of dye were observed as side effects of hypercapnia. The use of mannitol combined with hypercapnia appeared to be harmful. A PaCO2 level between 45 and 55 mm Hg increases perfusion in areas of mildly reduced rCBF.

Animals↗
PubMedDate not supplied

The effects of calcium antagonism on the epicerebral circulation in early vasospasm.

We have studied the effects of the calcium antagonist verapamil on the epicerebral arteriovenous transit time and regional epicerebral circulation of dogs by direct measurement of arterial diameters, fluorescein angiography, and krypton-85 regional epicerebral blood flow analysis. A large craniectomy was performed and vasoconstriction was induced by the subarachnoid injection of human platelet-rich plasma (PRP) pretreated with 25 mu M of ADP to cause maximum aggregation. Once vasoconstriction was established, verapamil (0.1 mg/kg) was topically applied to the perforated arachnoid. The PRP-ADP produced a mean decrease in the arterial diameters of 38.2 +/- 1.6% (p less than 0.01) at 10 minutes after its injection and verapamil produced a mean dilatation of 19.5 +/- 2.5% (p less than 0.01), compared to control values. Regional epicerebral blood flow was 54.9 +/- 3.4 ml/100 g/min in the control state, 34.8 +/- 3.2 ml/100 g/min (p less than 0.01) during vasospasm, and 78.2 +/- 4.5 ml/100 g/min (p less than 0.01) after verapamil. Fluorescein angiography, after verapamil, demonstrated a mean acceleration of the arteriovenous circulation time of 4.5 +/- 0.8 seconds (p less than 0.01) compared to the spasm value. We concluded that the topical application of verapamil can dilate previously constricted cortical arteries and that this dilatation is associated with acceleration of the epicerebral transit time and increased cerebral blood flow.

Administration, Topical↗