Positive evidence that the spinal cord, when completely severed from the brain centers with which it is normally associated, is capable of establishing a substitute or 'conditioned' response (CR) has not hitherto been reported. 8 Heretofore the higher brain levels, whether of cortex (
Rats with Walker tumor injected intramuscularly in both hind legs and subjected to forced swimming for 15 min daily for 10 days displayed a trend toward decreased lesion size, especially in older intact animals as compared to unexercised intact or bilaterally adrenalectomized controls. Secondary tumor nodules occurred at the lower abdominal or inguinal areas and appeared to be more extensive in the older exercised rats. The survival rates offorced exercised rats bearing Walker tumor cortically did not differ significantly from the respective controls as was also the case with adult BDF1 mice with intraperitoneal or cortical L1210 tumor and subjected daily to electroshock at 0.25 mA for 15 min.
The effects of tumor cells implanted into the brain of animals on survival rates and gross and microscopic brain changes have been ascertained. Walker carcinosarcoma 256 cell suspensions were injected at several brain sites in rats and leukemia L1210 and P388 and Ehrlich ascites tumor cells, intracerebrally into BDF1 mice. Such neoplasms provided for rapid and rather predictable growth increments. The survival rates were dependent on the number of cells introduced, those receiving the higher counts succumbing first. The brains of the animals revealed fairly discrete space-occupying lesions and neurological symptoms became apparent only hours before death due to intracranial pressure.
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