Mary K. Hammock

Spinal descent of cerebrospinal fluid in man

The descent of radiopharmaceuticals injected within the right lateral ventricle toward and into the spinal subarachnoidal spaces has been followed by scintiphotographic techniques and by computerized flow analysis in a group of “normal” patients. A substantial and rapid downward progression of the albumin-tagged tracer has been observed. This progression is faster than the subarachnoidal ascent toward the convexity of the brain.

Radionuclide scanning and microangiography of evolving an completed brain infarction A correlative study in monkeys

A correlative study between sequential radionuclide brain scanning and time-lapse microangiograms has been carried out in an experimental model of ischemic cerebral infarct in monkeys. In the majority of animals, brain scintigraphy became positive by two weeks, then regressed toward negative by four to six weeks after ligation of the middle cerebral artery. Increased radioisotope uptake is clearly related to neovascularization around the area of infarct as shown by the microangiograms. At later stages, decreased vascularity, peripheral gliosis, and central cavity formation are the main factors determining diminution of radionuclide penetration in the involved area.

Evidence for Choroid-Plexus Arsorption in Hydrocephalus

Abstract Radioiodinated (131ǀ,nl) serum albumin was injected into the lateral ventricles of eight hydrocephalic children, and the changes in isotope concentration in ventricular fluid, blood and urine were sequentially determined over an interval of 72 to 96 hours. Bilateral excisions of the choroid plexus were eventually performed on seven of these patients, and the findings before and after surgery were compared. In severe progressive hydrocephalus, a substantial transventricular absorption of albumin occurred hourly into blood, with eventual extraction in urine. At operation (72 to 96 hours after intraventricular injection), appreciable concentrations of the isotope were present in the choroid plexus and brain parenchyma; after removal of the choroid plexus, the rate of change of intraventricular isotope concentration showed a substantial decrease (average of 48 per cent) and the blood and urine concentrations were similarly reduced. All patients remained hydrocephalice after operation, and in most cas...

Physiological studies on the development of obstructive hydrocephalus in the monkey

OBSTRUCTIVE HYDROCEPHALUS is a condition of diverse etiologies with similarities in their development and course suggesting a common underlying mechanism. The experimental observations indicate that the production of cerebrospinal ffuid (CSF) in hydrocephalic animals and human beings is unchanged from the norma1.1,2 It is not surprising, therefore, that obstruction of the normal pathways by which CSF leaves the ventricular system results in enlargement of the ventricles. In some cases, an alternative pathway of CSF reabsorption may exist, since a significant number of patients develop “arrested hydrocephalus” wherein the hydrocephalic process progresses to an extent and then spontaneously stabilizes without further progre~sion.~,~ There are indications that there is a flow of CSF through the ventricular wall in hydrocephalus.5 The purposes of these studies in acute obstructive hydrocephalus of the monkey were [ 11 to determine the permeability characteristics of the brain capillaries and parenchyma, [2] to determine the size and compartmentilization of the enlarged “spaces” seen in light and electron micrographs of hydrocephalic brains,697 and [3] to evaluate the CSF production rates in hydrocephalic monkeys.

Recent studies on the formation of cerebrospinal fluid.

The major fraction of the cerebrospinal fluid (csf) is formed in the cerebral ventricles. The choroid plexuses contribute to this formation, although there is growing evidence that extrachoroidal sites may be equally important. The exact mechanism of csf formation is unknown, but ultrafiltration is probably involved to a considerable extent. There is probably a steady, net addition of new fluid at all points along the pathways of csf circulation until the major sites of absorption are reached.

Acute unilateral hydrocephalus resulting from oedematous occlusion of foramen of Monro: complication of intraventricular surgery.

Transcerebral removal of a small choroid plexus papilloma in the region of the foramen of Monro was followed within 48 hours by severe and progressive unilateral hydrocephalus. Acute unilateral hydrocephalus is a hitherto unrecognized complication of intraventricular surgery.