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 α-, β- and γ-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 Bouin's 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.     

Intracranial hemorrhage in the full-term neonate and young infant: correlation of the location and outcome

The cranial computed tomography (CT) and outcome for 13 full-term neonates and 12 young infants with intracranial hemorrhage (ICH) were studied. The full-term neonates had perinatal asphyxia or neurological signs such as seizures. All infants were breast-fed and showed bleeding diathesis. In the full-term neonates there was a high incidence of intraventricular hemorrhage (IVH) and hemorrhage around the falx. The location of the hemorrhage on CT and brain pathology suggested that the original site of IVH might be the choroid plexus vessels in the lateral ventricle or in the subependymal layer. On the other hand, the sites of ICH in infants were multifocal compared with those in full-term neonates. Subdural hemorrhage (SDH) was seen more frequently and IVH less frequently in infants than in full-term neonates. The cases with SDH frequently showed accompanying cerebral infarction followed by porencephaly. Thus, SDH with cerebral low density on CT may predict a poor prognosis.     

An intrathoracic vagus nerve schwannoma invading the trachea

A patient with a schwannoma of the intrathoracic vagus nerve is presented. The tumor invaded the trachea and caused dyspnea. It was successfully excised by a segmental resection of the trachea with end-to-end anastomosis. This instance of an intrathoracic vagus tumor invading the trachea is, as far as we know, the first reported in the world.     

Enzyme-linked immunosorbent assay for apolipoprotein B on dried blood spot derived from newborn infant: its application to neonatal mass screening for hypercholesterolemia

Hypercholesterolemia is a risk factor for atherosclerotic cardiovascular disease, and early diagnosis and treatment should be given attention. We developed a simple and sensitive enzyme-linked immunosorbent assay (ELISA) for apolipoprotein B (apoB) on a dried blood spot (DBS). The specificity of this assay was investigated by constructing curves for other proteins. The cross-reactivity was negligible. The mean intra- and intercoefficients of variation were 5.2 and 7.8%, respectively. We used phosphate buffer with Triton X-100 for extracting apoB on DBS. The elution of apoB was stable up to 30 days after bleeding. The correlation between plasma and DBS apoB was r = 0.94, p less than 0.005, n = 55. Using this method, we screened 2,500 babies between 5 and 7 days of age. The mean +/- SD of DBS apoB was 75 +/- 15 U. Seven hypercholesterolemic neonates were detected. Family studies of these neonates disclosed one definite and two suspected heterozygotes for familial hypercholesterolemia. Four other neonates showed no related familial background. This ELISA method for assaying apoB should prove to be a useful tool for large mass screening for hypercholesterolemia, particularly in the newborn.