✓ The effect of buffered 5-hydroxytryptamine (5-HT) on the blood-brain barrier to 125I-albumin was studied in 14 rhesus monkeys. Buffered 5-HT was introduced into the lateral ventricle by ventriculocisternal perfusion, resulting in a concentration gradient in the periventricular tissue from 1 to 800 times endogenous levels. Buffered 5-HT failed to induce an increase in periventricular vascular permeability to 125I-albumin. The author suggests that previous contrary reports from other laboratories may have resulted from species differences and failure to control certain physiological parameters including the use of highly acidic 5-HT preparations.
Albert N. Martins, Archimedes Ramirez, Lewis S. Solomon and G. Michael Wiese
✓ The standard ventriculocisternal perfusion technique was used to determine what effect a single large intravenous dose of dexamethasone would have on CSF formation rate in the rhesus monkey over a 4-hour period. Three monkeys received 0.15 mg/kg, four received 0.4 mg/kg and five served as the untreated controls. With time, CSF formation rates decreased in both treated and control groups. The magnitude of the decrease in the treated and untreated controls did not differ significantly. We conclude that the therapeutic benefit of dexamethasone for intracranial spatial decompensation derives from a mechanism of action that leaves the rate of CSF formation unchanged.
Peter V. Hall, John E. Kalsbeck, Henry N. Wellman, Solomon Batnitzky, Robert L. Campbell and Sidney Lewis
✓ Radioisotope ventriculography was applied clinically in myelodysplastic hydromeyelia in three groups of patients: two patients with normal ventricles, two with obstructive hydrocephalus, and 16 with myelodysplasia. In the myelodysplastic group, radioassay in one patient demonstrated flow of radioisotope down the hydromyelic cavity. Twenty scintigraphic studies on 16 myelodysplastic patients showed hydromyelia was present in all patients with spontaneously compensated hydrocephalus but in none of those with functional ventricular shunts. This relation between the hydromyelia and disordered ventricular hydrodynamics supports the Gardner hypothesis of myelodysplasia. Radioisotope ventriculography appears a safe and useful method of diagnosing hydrosyringomyelia and evaluating treatment by means of ventricular decompression.