Experimental studies of cerebral edema have found that neutral and positively charged molecules can flow into ventricular CSF (Reulen et al., 1978) but molecules that are negatively charged at physiological pH, such as albumin and fluorescein isothiocyanate, flow to the subarachnoid CSF (Ohata and Marmarou, 1992). Here, ALB is linked to brain edema.