No abstract

We compared the morphology and stability of hybridization signals between paraffin sections of rat retina fixed with commonly used 4% paraformaldehyde/PBS and those fixed with a fixative containing glutaraldehyde in in situ hybridization histochemistry, using a digoxigenin-labeled RNA probe complementary for beta-galactoside alpha 2,6-sialyltransferase mRNA. Retinal detachment was frequently observed in the sections fixed with 4% paraformaldehyde-PBS, whereas the morphology was satisfactorily preserved in those fixed with either 0.5% glutaraldehyde, 4% paraformaldehyde-PBS, or 2.5% glutaraldehyde-PBS. Without glutaraldehyde, it was difficult to determine the most appropriate length of proteinase K digestion of tissue sections for facilitating probe penetration, since the optimal time for definite hybridization was variable among the retinal cells in heterogeneous layers. By addition of glutaraldehyde to paraformaldehyde or with glutaraldehyde alone, it was easy to establish the appropriate time for the unmasking procedure, since intense mRNA signals were constant throughout the retina by proteinase K digestion for more than 30-40 min. Using a fixative that causes stronger cross-linking (e.g., glutaraldehyde) is recommended to improve not only the morphology but also the stability of hybridization signals in in situ hybridization histochemistry with paraffin embedding and digoxigenin-labeled RNA probes.

Blood staining of the cornea was studied by light and electron microscopy: a 55-year-old male with Hansen’s disease had blood staining of the cornea due to intracorneal hemorrhage; he received a partial-thickness keratoplasty following 1 year after the onset of the staining. The excised specimens revealed deposits of degraded erythrocytes in the stroma. Numerous dense granules, probably of erythrocytic breakdown products, were phagocytosed by macrophages as well as parenchymal cells. The presence of macrophages was limited to the middle part of the stroma in which newly formed vessels were remarkable.

Topically applied bupranolol, a Β-adrenergic blocking agent, has been shown to have a marked effectiveness in lowering the intraocular pressure of the normal and glaucomatous eyes. The effects were not only seen in the treated eyes but also in the untreated, contralateral eyes. The contralateral response was independent of the ongoing diurnal variation of the intraocular pressure. Instillation of the drug into the nasal cavity induced decrease of the intraocular pressure in both eyes, the extent of which was comparable to the contralateral response induced by ocular instillation. These observations suggest that the contralateral response is caused by systemically absorbed drug, probably due to the action on the central locus regulating the intraocular pressure. Instillation of pilocarpine did not show any similar contralateral response.

High resolution ultrasonic biometry was performed on 3 normal volunteers (19–21 years of age) before and at 15-min intervals following topical application of 1% bupranolol and 2% pilocarpine. Bupranolol, a new β-adrenergic blocking agent, which lowers intraocular pressure of the normal and glaucomatous eyes, did not show any measurable change in the depth of the anterior chamber and thickness of the lens. On the other hand, all the subjects demonstrated a considerable degree of shallowing of the anterior chamber depth and thickening of the lens after instillation of pilocarpine.