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Biomedical subjects

A Bill

Publications and source records attributed to A Bill.

At least 91 records · Page 5Linked to original sources
PubMed1977

Elimination of protein A-IgG complexes from the blood circulation in rabbits: role of spleen and liver.

We studied the elimination from rabbit circulation of soluble immune complexes made with staphylococcal protein A and rabbit IgG. In in vivo experiments the complexes were cleared from the circulation by the liver and spleen. In the saline perfused isolated liver there was rapid uptake of protein A-IgG complexes which indicated that the elimination of these complexes by fixed tissue macrophages may occur independent of complement components.

Animals↗
PubMed1977

Formation and drainage of aqueous humor following total iris removal and ciliary muscle disinsertion in the cynomolgus monkey.

Aqueous humor formation (AHF), uveoscleral flow (U), gross outflow facility (Cg), true facility of outflow from the anterior chamber (Ct1), true facility of outflow from anterior chamber into the general circulation (Ct2), and the pressure sensitivity of AHF (pseudofacility; Cps) were determined in cynomologus monkey eyes which had undergone total iris removal or iris removal followed by ciliary muscle disinsertion. AHF was in the normal range in iridectomized-only eyes. AHF was present but reduced in "disinserted" eyes. U was markedly reduced and similar in both types of eyes. Cps was normal and Cg, Ct1, and Ct2 were low in "disinserted" eyes. Cg, Ct1, and Ct2 were nearly equal in the "disinserted" eyes, indicating that gross facility consisted almost entirely of pressure-dependent flow from anterior chamber into the general circulation, presumably via the conventional drainage routes.

Animals↗
PubMed1976

Sympathetic control of cerebral blood flow in acute arterial hypertension.

The cervical sympathetic chain on one side was stimulated electrically at 10-20 Hz and an acute rise in arterial blood pressure was produced by: intravenous injection of angiotensin, ligation of the thoracic aorta, or ligation of the aorta combined with injection of metaraminol. The blood flow through the cerebrum and the cerebellum was determined by using labelled microspheres. At high blood pressures there was multifocal breakdown of the blood-brain barrier in the cerebrum as indicated by leakage of Evans blue. The breakdown was restricted to the control side or much more marked on that side than on the stimulated side. Sympathetic stimulation prevented also breakdown of the blood-aqueous barrier. The blood flow through the cerebrum on the control side was higher than that on the stimulated side in all experiments. Regions with breakdown of the blood-brain barrier had flow rates which were about 10 times normal values. Cerebellar blood flow was less affected by the hypertension and did not react significantly to sympathetic stimulation. The results indicate that stimulation of the sympathetic nerves to the brain tends to prevent forced dilatation of the arterioles with a resulting regional overperfusion with blood and breakdown of the blood-brain barrier. It is concluded that one role of the sympathetic nerves supplying the brain is to extend the pressure region with autoregulation in its upper part under conditions of a general increase in sympathetic vasomotor activity.

Acute Disease↗
PubMed1975

Blood circulation and fluid dynamics in the eye.

The nutrition of the intraocular tissues is accomplished by the retinal vessels, the uveal vessels, and by the aqueous humor. Both morphologically and physiologically the retinal vessels are similar to those in the brain. The endothelial cells of the capillaries are attached to each other by tight junctions, the resistance vessels respond poorly to a large number of drugs, and the blood flow through the retina is autoregulated and very little affected by the sympathetic nervous system. The blood vessels of the iris also have morphological and permeability characteristics similar to those in the brain but they are under a strong influence from the sympathetic nerves and react to many drugs. The blood flow is autoregulated. The blood vessels of the choroid and the ciliary processes are similar to those in the small intestine and in the kidney. The endothelial cells of the capillaries are fenestrated; the vessels respond to sympathetic nervous stimulation and to a large number of vasoactive drugs. Autoregulation of the blood flow is intermediate in the ciliary body and very poor or absent in the choroid...

Animals↗