Clarence Dennis

Decerebration in the Dog by Complete Temporary Anemia of the Brain

In many investigations, it is desirable to perform experiments upon animals in the absence of anesthetics. The usual procedure is that of Sherrington, namely, to decerebrate surgically under ether, to stop the anesthesia, and to proceed at once with the experiment. 1 Under such conditions, profound shock and the depression due to the residual anesthetic agent throw some doubt on the reliability of the results. A more delicate method of decerebration has been devised for the cat by Pollock and Davis. 2 In this method, an anemic decerebration is produced by ligation of the basilar and carotid arteries under ether anesthesia. In the dog, the inaccessibility of the basilar artery makes this a difficult method. It has been shown that the nerve cells of the brain stem are much more resistant to anemia than are those of the cerebral hemispheres, 3 It is therefore possible to produce extensive cerebral damage by a period of anemia which will allow the cells of the brain stem to recover. Guthrie, Pike and Stewart 4 and Gildea and Cobb 5 studied the effects of temporary occlusion of the 4 chief cerebral vessels in the neck under ether anesthesia, and were unable to predict the severity of the destruction produced by a given period of such occlusion. The variability in their results was due primarily to their failure to interrupt the flow in the spinal arteries, which is not constant from animal to animal. A further uncertainty must have resulted from variations in the depth of anesthesia just prior to the occlusion of the cerebral vessels. We have devised a method of decerebration depending upon complete temporary anemia of the brain of the dog in the absence of anesthetics. A preliminary surgical procedure is used, consisting in removal of both laminæ and spine of the second cervical vertebra and ligation of both vertebral arteries. After an interval of one to 2 weeks, the dog is given one to 2 mg of atropin sulfate to prevent vagal cardiac inhibition, and placed, back down, on the table.

Behavior of Dogs after Complete Temporary Arrest of the Cephalic Circulation.

The authors have previously reported a method of decerebration of the dog by means of cephalic vascular stasis. 1 The emphasis at that time was upon the use of the procedure as a method for preparing decerebrate animals. Since that time our interest has shifted to the evidence that could be gained concerning the resistance of various cells in the brain to temporary cessation of blood flow and the correlation of these changes with changes in the behavior of the animal. The technic has been modified to the following form: Two days after laminectomy at the second cervical level, the animal is atropinized, and a metal tracheal tube is inserted orally. A blood pressure cuff is wrapped about the neck, and the pressure is raised quickly to 700 mm Hg, at which level it is maintained as long as vascular arrest is desired, artificial respiration being administered through the tracheal tube. The completeness of circulatory arrest in the head is determined by ophthalmoscopic examination of the retinal vessels. With this technic, consciousness is lost in a very few seconds, the corneal reflex disappears in from 20 to 40 seconds, and spontaneous respiration ceases in from 40 to 90 seconds. In 6 adult animals there was complete cessation of cephalic blood flow for periods of from 2 to 10 minutes. In the dogs subjected to 8 minutes or less of compression the lid wink returned in 5 to 8 minutes; in 2 animals treated for 10 minutes it did not return till later. The first gasp occurred in 1 to 5 minutes and satisfactory spontaneous respiration returned in 2 to 11 minutes, the slowest return being after the longest compression. Intermittent spontaneous, high-pitched vocalization, associated with vigorous running movements of all 4 limbs, with the dog lying on his side, often occurred during the first few hours.

The relationship of chronic ulcerative colitis and cirrhosis.

Excerpt The etiology of idiopathic ulcerative colitis is obscure; the same statement applies equally well to most types of human cirrhosis. The occurrence of two such diseases in the same patient r...

Mechanism of Insulin Convulsions. III. Effects of Varying Partial Pressures of Atmospheric Gases After Adrenalectomy

Conclusions Anoxic anoxia (breathing 5% O2 plus 95% N2) causes hypoglycemia in adrenalectomized dogs without insulin in contrast to the hyperglycemia observed in normal animals. Insulin convulsions are prevented by anoxia of this degree even when the fall in blood sugar is maximal. Breathing 15% CO2 likewise tends to prevent insulin convulsions from occurring.

Production of a Hemorrhagic State by the Infusion of Hemolyzed Blood.

Summary A syndrome of prolongation of blood coagulation time, gastro-intestinal bleeding and petechiae is described. This condition can be produced in the dog by the infusion of hemolyzed blood.

An Oxygenator with Increased Capacity Multiple Vertical Revolving Cylinders.

Conclusions 1. An oxygenator consisting of 8 concentric revolving cylinders which utilizes a funnel to deliver the blood into a small cup is described. 2. Animal perfusions demonstrate that its efficiency as an oxygenator is high enough to make it possible to perfuse the entire animal body without using an impractically large amount of blood in extra-corporeal circulation.

Resistance of Young Dogs to Acute Arrest of the Cephalic Circulation.

The observation has been made by several investigators that the young animal is much less susceptible to asphyxia than the adult. 1 , 2 No information has been available, however, concerning the essential factors involved in the greater resistance of the young to asphyxia. It was of interest, therefore, to determine whether the brain itself is more resistant to anoxia and accumulation of metabolites in the young animal. This question has been investigated by comparing the effects of complete arrest of the cephalic circulation for various periods of time in adult dogs and in puppies. The method which has been employed to produce sudden complete stasis of blood in the head by means of a pressure cuff in the cervical region has been described 3 as has also the effects of this procedure on adult animals. 4 The adult dog rarely recovers consciousness after 8 minutes of complete vascular occlusion. It remains comatose as long as it lives, losing all sensation and retaining only very primitive responses on the reflex level. After 6 minutes of vascular stasis, consciousness is recovered in 24 to 48 hours as a rule and following this, the animal is very severely ataxic, restoration to normal requiring a period of weeks or months. Following 4 minutes of arrest of the cephalic circulation, consciousness returns in 18 to 24 hours and the residual ataxic symptoms, though somewhat less severe, are still present. After only 2 minutes of vascular occlusion, slight ataxia persists for a week or more. Complete arrest of the cephalic circulation was produced in 8 puppies using the same technic as had been employed in the study of adult animals. The results of temporary cessation of the brain circulation in these animals are in striking contrast to the effects of the procedure in the adult.

Validity of the bromsulphalein test in patients with acute severe upper gastrointestinal hemorrhage

Abstract The bromsulphalein retention test has been used as a screening test to detect unsuspected liver disease in 382 patients presenting with acute gastrointestinal bleeding. Sixty-six of these patients showed abnormal retention on the admission test. Later evaluation indicated that only twenty-five of these patients had true liver disease; thirty-five had normal livers and in six patients the liver status could not be determined. The possible factors responsible for abnormal bromsulphalein retention in patients with normal livers are discussed.

Evaluation of Vagotomy in Chronic, Non-Specific Ulcerative Colitis

Conclusion Preliminary investigation indicates that vagotomy offers sufficient promise in chronic, nonspecific, ulcerative colitis to justify further investigation.

Some effects of paracolon bacteremia.

Conclusion Dogs receiving an intravenous infusion of a 14 hour culture of the Paracolon Bacillus exhibited profound illness and rapid death. Canine experiments in which conclusions are to be based on survival in apparent health for more than 2 or 3 hours should be conducted with precise aseptic technic rather than general cleanliness alone, in order to eliminate the influences of bacterial contamination.