Lectin (UEA-1) reaction of capillary endothelium with reference to permeability in autopsied cases of cerebral infarction

The relationship between endothelial reactivity to Ulex europaeus agglutinin-1 (UEA-1) and the permeability of the vascular wall in human autopsied cases of cerebral infarction was studied. Sections from the cerebral cortex were reacted with horseradish peroxidase UEA-1 to demonstrate the surface membrane of endothelial cells. Albumin in the neuropil of sections was demonstrated for the estimation of increased vascular permeability. The results showed that endothelial reactivity to UEA-1 was reduced in cases where death had occurred 3 to 5 days after onset of cerebral infarction. Reactivity was also diminished in cases where death had occurred after 13 and 25 days; these cases showed fresh ischemic lesions caused by re-attacks of infarction. Albumin extravasation into the neuropil was demonstrated in these intermediate cases. Chronic cases, dying after more than 52 days, showed no reduction of endothelial reactivity to UEA-1 and no albumin extravasation was proved. It was concluded that UEA-1 can be employed as a useful morphological marker for evaluation of endothelial function and vascular permeability.     

Demonstration of receptors for parathyroid hormone on cultured rabbit costal chondrocytes

Parathyroid hormone (PTH) receptors on cultured rabbit costal chondrocytes were demonstrated using HPLC-purified, radioiodinated [Nle8,-Nle18, Tyr34] bovine PTH-(1-34)amide. PTH binding was found to be specific for PTH agonists and antagonists and dependent on the time and temperature of incubation. Both growth cartilage (GC) cells and resting cartilage (RC) cells were shown to have a single class of saturable, high affinity PTH binding sites with a dissociation constant of 0.6-0.7 nM. However, the numbers of receptors per cell were approximately 49,000 on GC cells and 19,000 on RC cells. After crosslinking the receptors on these cells with the radioligand, one, major 125I-labeled band of 76 kDa was separated by SDS-PAGE.