can be firmly fastened to the lobe of the ear in such a way that the disc of the electrode rests directly over the front surface of the ear lobe. A paste made of kaolin and saturated zinc sulphate solution establishes contact between the electrode and the skin. A puncture made previously through the skin with a fine hypodermic needle eliminates the resistance of the skin under this electrode. This electrode remains fixed to the ear throughout the examination. The other electrode consists of a small silver-plated phosphor-bronze disc which is built into the end of an
Curt P. Richter and Frank J. Otenasek
Curt P. Richter
normal skin resistance does not give constant outlines of areas denervated by peripheral nerve lesions or sympathectomies. Adequate information is not yet at hand as to the constancy of outlines obtained with furmethide. STEPS INVOLVED IN OUTLINING AREAS OF SKIN DENERVATED BY PERIPHERAL NERVE INJURIES (1) Cleanse ear lobe with alcohol and prick skin with hypodermic needle to eliminate skin resistance. (2) Place paste (kaolin and saturated zinc sulphate solution) or electrode jelly on disc of clip electrode, fastening electrode to ear lobe
Franc D. Ingraham, Eben Alexander and Donald D. Matson
silicate, called kaolin, into rats will also produce hydrocephalus. This method was widely used by Lindauer and Griffith, 22 Griffith, Jeffers, and Lindauer, 16 Griffith and Roberts, 17 , Griffith, Jeffers, and Fry, 15 and Griffith, Fry, and McGuinness. 14 Their primary interest was in coincidental hypertension that was produced, but subsequently attention was focussed on the study of papilledema occurring in experimental hydrocephalus in rats. Stuck and Reeves 28 have found that thorotrast, a colloidal preparation, when introduced into the cisterna magna of
Curt P. Richter and Frederick G. Whelan
polished pure zinc discs 1¼ inches in diameter and a paste made of kaolin and saturated zinc sulphate solution, or the regular plates and electrode jelly that are used to record the electrocardiogram. The following instructions give the steps involved in the operation of the galvanometer: 1. Attach electrodes to skin and connect to binding posts on control panel. 2. Turn on amplifier ( Fig. 2—switch D ) and allow to warm up for several minutes; turn on battery switch on panel. 3. Set double-pole, double-throw switch on panel to “zero.” 4
And Methods of Producing Communicating Hydrocephalus in the Dog
Peter H. Schurr, Robert L. McLaurin and Franc D. Ingraham
symptoms and signs of obstruction. The volume of Pantopaque used is not the operative factor, since there was no enlargement of the ventricles of a dog 5 weeks after a cisternal injection of 6 cc. of the substance. Obstruction in the interpeduncular and neighboring cisterns was produced in dogs by the following method. A polyethylene tube was introduced into the interpeduncular region through a subtemporal craniotomy under intravenous Nembutal anesthesia. The animals were then kept in a prone position while injections of a suspension of 250 mg. of kaolin * in 2 cc. of
Edgar A. Bering Jr.
sometimes difficult because of variations in the amount of tracer injected. This difficulty has been resolved by assigning the value 100 to the tracer specific activity of the serum 3 hours after injection of the tracer. Observed specific activity values are then recalculated by the following formula: Hydrocephalus was produced in the dogs by cisternal injection of 750 mg. kaolin. The choroid plexectomies and plugging of the foramen of Monro were carried out through occipitoparietal incisions in the cerebral cortex. Gelfoam soaked in kaolin was used to plug the
Joseph G. Chusid, Lenore M. Kopeloff and Nicholas Kopeloff
injected intracisternally with an antiseptic (1:6 Di-4′-chlorophenyldiguanidohexane) epileptic seizures and death occured in 24 hours after injection. According to McLaurin and co-workers, 8 intracisternal injections of kaolin (aluminum silicate) in dogs can produce severe chronic adhesive arachnoiditis with resultant communicating hydrocephalus and myelomalacia of the cervico-thoracic spinal cord. Convulsive seizures, however, were apparently not observed in these animals nor were they mentioned in the earlier report of Dixon and Heller, 2 who used intracisternal
Robert G. Fisher and John H. Copenhaver Jr.
horizontally at the level of the cistern. Fluid was collected and the flow was measured at 10-minute intervals. A steady state of flow was obtained before the drug was administered intravenously. Studies of the flow were made 1 hour before and after the administration of Diamox. The animal was then sacrificed and the choroid plexus, a sample of blood, and a kidney were studied. To study the effect of increased intracranial pressure on the content of enzymes in the choroid plexus, kaolin (0.5–1.0 cc.) was injected into the cisterna magna of a cat after the initial pressure
responsible for androgen-induced sterility in the female rat. Endocrinology , 1961, 68: 68–79. 3. Bradbury , J. T. Personal communication , 1961 . Bradbury , J. T. Personal communication, 1961. 4. Bradbury , J. T. , Brown , E. S. , and Brown , W. E. Adsorption of urinary gonadotrophins on kaolin. Proc. Soc. exp. BioL, N.Y. , 1949 , 71 : 228 – 232 . Bradbury , J. T., Brown , E. S., and Brown , W. E. Adsorption of urinary gonadotrophins on kaolin. Proc. Soc. exp. Biol., N
Demonstration of the Choroid Plexuses as the Generator of the Force for Flow of Fluid and Ventricular Enlargement
Edgar A. Bering Jr.
hydrocephalus and on hydrocephalus induced previously. The surgical procedures of ventriculotomy and choroid plexectomy were done aseptically in a manner similar to that of others. 4, 6, 7 Hydrocephalus was produced by intracisternal injection of 0.25 to 0.5 gm. kaolin suspended in cerebrospinal fluid which produced a sterile reaction occluding the outlets to the 4th ventricle. 13 Three to 4 weeks were allowed between any two procedures. Measurements of pressure were made with Statham strain gauges led to a Sanborn recorder. At the time of sacrifice the animals were given