Toshio Masuzawa

Immunohistochemical localization of Na+, K+-ATPase in the choroid plexus

To determine if canine and rat choroid plexus Na+,K+-ATPase can be localized by immunoperoxidase staining after fixation and embedding, we prepared rabbit antiserum to purified canine kidney medulla Na+,K+-ATPase. When sodium dodecylsulfate polyacrylamide electrophoretic gels of purified canine kidney Na+,K+-ATPase and canine kidney microsomes were treated with antiserum followed by [125I]protein A and autoradiography, the canine microsomes and purified Na+,K+-ATPase showed a prominent radioactive band coincident with the alpha-, beta- and gamma-subunits of the purified canine kidney enzyme. When the rabbit immunoglobulin that was purified from the Na+,K+-ATPase antiserum through DEAE-cellulose ion exchange chromatography was used for immunoperoxidase staining of the choroid plexus fixed with Bouins fixative, intense immunoreactive staining was present on the epithelial cells of both choroid plexuses but was not found in the tissue around the vessel. The staining was especially confined to apical surfaces of the epithelial cells. The same procedure was performed in the canine kidney, and immunostaining was obtained in the tubules where Baskin and Stahl described the enzyme localization. No staining was seen with pre-immune serum of the normal rabbit. We concluded that both the canine and rat choroid plexus are rich in Na+,K+-ATPase, which plays an important role in cerebrospinal fluid (CSF) secretion.

Cytochemical study on enzyme activity associated with cerebrospinal fluid secretion in the choroid plexus and ventricular ependyma

Normal adult albino and Sprague-Dawley rats, under intraperitoneal Nembutal anesthesia, were used to demonstrate enzymatic activity in the choroid plexus and ventricular ependyma. The brain tissues were perfused or immersed with cold 2% glutaraldehyde and 8% sucrose in 0.1 M cacodylate buffer (pH 7.2-7.4) for 30 min and washed overnight in the same buffer solution., The choroid plexus (lateral and fourth ventricles) and ventricular ependyma (lateral ventricle) were trimmed from the fixed and washed brain tissues, which were frozen and sectioned. For histo- and cyto-chemical study, the sections were immersed in the following incubation media; for Na+, K+-ATPase (ouabain-sensitive, K+-dependent, p-nitrophenylphosphatase: p-NPPase) according to the one-step method of Mayahara et al. (1978): for Mg2+- ATPase, Wachstein-Meisels incubation medium (1957); for adenylate cyclase (AC), following Araki and Saitos lead citrate method (1979). The cytochemical findings gave the following results. In the choroid plexus, the ouabain-sensitive electron-dense reaction products of NA+, K+-ATPase (p-NPPase) were strongly positive in the microvilli and along the inner surface of microvilli, without showing any Mg2+-ATPase and AC activities, and all three enzymatic activities were positive along the basal plasmalemmas and negative along the lateral and apical (not including microvilli) plasmalemmas. In the ventricular ependyma, Na+,K+-ATPase (P-NPPase) activity was not found, and the reaction product of AC was observed on the apical plasmalemmas and those of Mg2+-ATPase along the basal plasmalemmas. These cytochemical findings are helpful in understanding the regulation of cerebrospinal fluid production through Na+, K+-ATPase (p-NPPase) and cyclic AMP (AC).

Trigeminal neurinoma revealed by intratumoral hemorrhage following a minor head injury

A trigeminal neurinoma which produced the signs and symptoms of a localized intratumoral hemorrhage without showing any extratumoral hemorrhage successive to a minor head injury is reported here. A 33-year-old man noticed pain and hypesthesia on the right side of the forehead and double vision on the day following an occipital trauma. A computed tomographic scan demonstrated a large high-density mass in the anterior part of the right cerebellopontine angle. A diagnosis of trigeminal neurinoma was made and the tumor was successfully removed. The largest part of the tumor consisted of a blood clot and necrotic tissue. In this case of minor head injury, the intratumoral hemorrhage was thought to have occurred as a result of obliteration of the lumen followed by recanalization of the meningeal vessels enclosed in the tumor by the growing neurinoma and distal vessel necrosis. Such a case of trigeminal neurinoma which revealed itself through intratumoral hemorrhage following a minor head injury has not been previously reported.

The development of intracranial aneurysms associated with pulseless disease

Two cases of pulseless disease associated with intracranial aneurysms, one located at the tip of the basilar artery and the other at the left internal carotid-posterior communicating artery junction which developed with episodes of subarachnoid hemorrhage due to their rupture, are presented. Whether the aneurysms and pulseless disease occurred independently or whether the aneurysms developed secondarily from the altered hemodynamic flow produced by pulseless disease is unknown; however, it is certain that abnormal intracranial hemodynamic forces play a role in the development of aneurysms.