Effects of genetic selection for high or low antibody response on resistance to a variety of disease challenges and the relationship of resource allocation.

Lines of white leghorn chickens were selectively bred for either a high (H) or low (L) antibody response to sheep erythrocytes. The parental lines, HH and LL, and reciprocal crosses, HL (sire line cited first and dam line second) and LH, were compared for their responses to various diseases. High antibody titers were associated with reduced body weight. Lines and their crosses were challenged with infectious diseases. The LL line was most resistant to Mycobacterium avium, whereas the HH line was most susceptible. The HH line was most resistant to Mycoplasma gallisepticum, whereas the LL line was most susceptible. These findings indicate that defense against infectious diseases are resource expensive. In order to save resources, it is possible that different parts of a population might genetically devote high levels of resources against different types of diseases so that the entire population is not susceptible to a single infection.

Posterior fossa partial trigeminal rhizotomy: an alternative to microvascular decompression.

Doctor Walter Dandy was a pioneer in the surgical treatment of trigeminal neuralgia. The Frazier-Spiller operation had been the standard operation for trigeminal neuralgia. Doctor Dandy pioneered the approach through the posterior fossa. He sectioned the lower-most 30 percent of the trigeminal nerve and found that trigeminal neuralgia was relieved. Anesthesia dolorosa did not develop, and the patients had only minimal sensory loss. Dandy's operation was not widely accepted, but microvascular decompression as described by Jannetta was developed by application of Dandy's principles. In twenty patients, we performed a partial trigeminal rhizotomy using Dandy's technique. A small sub-occipital craniectomy was performed and the trigeminal root entry zone exposed. The lowermost 30 percent of the trigeminal nerve was elevated with a blunt hook. The coagulating cautery was applied to the hook and the nerve partially sectioned. In each case, the trigeminal neuralgia was completely relieved. Each patient developed a minimal sensory loss in the second division of the trigeminal nerve. The corneal reflex was preserved in all cases. No patient has developed anesthesia dolorosa. Partial trigeminal rhizotomy is an alternative to microvascular decompression. The operation is technically easy to perform and should resume its rightful place in the neurosurgical treatment of trigeminal neuralgia.

Acute herniated nucleus pulposus with cauda equina compression syndrome following chemonucleolysis. Report of three cases.

Three cases of acute disc herniation causing cauda equina compression syndrome after chemonucleolysis are described. All three patients had myelographic blocks and, despite emergency decompression procedures, were left with residual neurological deficits. Recommendations are made regarding evaluation and therapeutic intervention, and possible etiologies of this problem are reviewed.

Spontaneous intracerebral hematoma in carotid-cavernous fistula. Report of three cases.

Spontaneous intracerebral hematoma associated with carotid-cavernous fistula is rare. Three new cases are presented. In each, the hemorrhage originated in the vicinity of localized intracranial venous engorgement, as demonstrated by cerebral angiography. Rupture of one or several of the distended venous channels from increased back-flow is postulated as the etiology of the intraparenchymal hematomas.