Keasley Welch

Concentration of Thiocyanate by the Choroid Plexus of the Rabbit in vitro.

Summary The choroid plexus of the rabbit was incubated in vitro in a medium containing S35 C N-. The thiocyanate was accumulated in the tissue against a gradient of concentration. The accumulation was impaired by both competitive and metabolic inhibitors and was proportional to the concentration of thiocyanate only at low concentration.

The function and structure of canine arachnoid villi.

Summary Perfusion of canine arachnoid villi reveals that these permit the open flow of fluid from the meninges to the superior sagittal sinus while they prevent flow in the opposite direction. Opening pressure below which flow does not proceed averages approximately 30 mm. of water. The structure of the villi has been studied in the dog and compared with that of the monkey. In the dog the villi are related directly to the sinus, are more meshlike or septate than tubular, and some present a unique feature which suggests a ball valve.

Cooperative phenomena in the permeation of sugars through the lining epithelium of choroid plexus.

Abstract The concentration of D -glucose alone or together with D -galactose, L -arabinose or D -fructose was measured enzymatically in new choroidal cerebrospinal fluid and in plasma, sampled simultaneously in rabbits. Plasma levels were systematically altered by the use of insulin or by the infusion of one or several sugars. The flow of glucose was approximately linear with plasma concentration to 14 m M while above 20 m M there was an interval of plasma concentrations in which there was a disproportionate increase in flow with increase in plasma level, suggesting increase in affinity of active sites or recruitment of new binding sites. For galactose, fructose and arabinose there was, with increasing plasma concentration, an inordinate increase in flow. Under the influence of high concentrations of galactose the behavior of glucose changed so that it was cooperative from the origin. The cooperative flow of fructose was greatly enhanced at levels of glucose at which recruitment of new glucose sites was greatest and cooperativity and flow fell off sharply at higher levels of glucose. The behavior and interactions are considered in terms of a mosaic of two carries, each a cooperative assembly, the state and thus the affinity for sugars being influenced by the local environment of sugars.

A model for the distribution of materials in the fluids of the central nervous system

Summary Consideration is given to the processes which govern the distribution of matter in the fluids of the brain. Because the real system is too complicated for precise treatment a simplified model is taken instead. The model is a slab in which there is a distributed source, the surface being bathed by a fluid which is mixed and continuously renewed. The behavior has been studied under a variety of circumstances and several examples of the application of the model are presented.

Subdural abscess with retinal thrombophlebitis.

THE CLINICAL PICTURE of cortical thrombophlebitis associated with pus in the subdural space has been established by Kubik and Adamsl and by Schiller, Cairns, and Russell.2 Usually secondary to infection of the paranasal sinuses, the symptoms are those of an acute, superficial hemispheral disturbance. The following case is reported because of the interesting retinal changes which occurred following evacuation of a subdural abscess.

Progress in Experimental Tumor Research, vol 17: Recent Advances in Brain Tumor Research

A productive interest in experimental brain tumor research at Ohio State University (Columbus) created the focus of this symposium held Oct 5 and 6, 1970, in connection with the observance of that institutions centenary year. Now, over two years later, the published record is made available. An introductory paper dealing with the approach to classification was followed by papers on the N-nitrosourea induction of neoplasia by Koestner et al, an account by Mahaley on antibody production to human gliomas, and three papers on virus-induced tumors, two from the Duke group and the other by Yohn. The use of tissue culture in the routine study of tumors was considered in the papers by Liss and Unterharnscheidt, and the metabolic aspects summarized in excellent papers by Lehrer, Kirsch et al, and Allen. This first days formal presentations were followed by a stimulating panel discussion. On the second day, Wechsler presented further observations

Homonymous hemianopsia following interruption of the parieto-occipital vein.

THE PARIETO-OCCIPITAL VEIN is a large vessel which leaves the surface of the cortex and enters the superior sagittal sinus at about the level of the paneto-occipital fissure. Its components are from both the medial and convex surfaces of the cerebral hemisphere. Although not singled out for description in most anatomic texts, it is well described by OConnell in his study of the superior cortical veins.5 Occlusion of this vein in human subjects results in homonymous hemianopsia which is likely to recover. The evidence for this is that contralateral hemianopsia has followed on each of three occasions when surgical situations have required that the vein be divided. During one of these operations, the patient was awake and able to cooperate in visual field examination; he was found to have developed an homonymous hemianopsia 35 minutes following occlusion of the vessel.