Photoinitiators and photoinitiation, 5. Photodecomposition of some α-hydroxymethylbenzion derivatives: Sulfonic esters

The photodecomposition of several sulfonic esters of α-hydroxymethylbenzion (1a) was studied by means of ESR and ¹H NMR-CIDNP techniques. An exclusive α-cleavage into benzoyl and α-hydroxy-α-sulfonyloxymethylbenzyl radicals ( 6 and 7 ) through a triplet excited state was observed. Radicals (7) were found to undergo elimination of sulfonic acid to give benzoylmethyl radicals (9) in an extremely fast process. Chemical confirmation was provided by naphthalene quenching and radical-trapping experiments using 1-dodecanethiol and 2,2,6,6-tetramethylpiperidin-1-oxyl, respectively. Photodecomposition of the sulfonic esters in the presence of 1,1-diphenylethylene as a model substrate for vinyl monomers indicated that both benzoyl and benzoylmethyl radicals are highly reactive towards the carbon-carbon double bond.     

Effect of monazite on body organs of rats

Biochemical and histological alterations in lungs, liver, and kidney of albino rats at different time intervals after an intratracheal administration of monazite, the chief source of thorium and some rare earth elements of industrial significance, were investigated. The mild enzymatic and morphological changes observed in the lung suggest an inert behaviour of the monazite dust towards this tissue. However, biochemical alterations in liver and kidney indicate slight dissolution of some constituents of this naturally occurring mineral from the pulmonary tissue to other body organs.     

Airway hyperreactivity in tropical pulmonary eosinophilia

Eosinophils were recently proposed to act as prime inflammation-producing cells in asthma. Tissue eosinophil infiltration is an important feature of another disease, tropical pulmonary eosinophilia. Airway reactivity was determined in two patients with the latter disease and both were found to be hyperreactive.     

Distribution of Müller cells in the turtle retina: an immunocytochemical study

Summary Müller cells are the major type of glial cell in the vertebrate retina, and appear to participate in important structural and metabolic functions. Although the morphological features of Müller cells have been extensively studied, their topographic distribution across the retina has not been previously reported. We have used a Müller cell-specific monoclonal antibody, 19–33, to study the distribution of Müller cells in turtle retina. The antibody was obtained during a search for cell type-specific monoclonal antibodies in the rat retina. Immunoblotting studies show that 19–33 reacts with a 58 KDa protein that is present in Müller cells. Immunocytochemical studies withen face sections of turtle retina show that the density of Müller cells is fairly uniform across the retina although there are small regional differences. We estimate that the mean Müller cell density is about 1600 cells mm^–2 of turtle retina and that each turtle retina contains about 54 000 Müller cells.     

Localization of cellular retinoic acid-binding protein to amacrine cells of rat retina

Monoclonal antibodies to performic acid-oxidized cellular retinoic acid-binding protein (CRABP) from bovine retina were prepared by fusion of spleen cells from immunized mice with mouse myeloma cells. Five antibodies were studied in detail. It was established by ELISA that the antibodies react with CRABP and oxidized CRABP, but not with other oxidized or unmodified retinoid-binding proteins. Competitive ELISA demonstrated that the antibodies react with heat-denatured antigen but not with native protein. Western blotting and immunostaining, following sodium dodecyl sulfate gel electrophoresis, provided evidence for recognition of a single component in retinal supernatants whose staining is prevented by preabsorption of the antibody with heat-denatured CRABP. The insoluble fraction from a retinal homogenate contains residual CRABP and two weakly-reacting components, whose staining is not affected by preabsorption of the antibody with antigen. Each antibody produces the same staining pattern on cryostat sections of rat retina by indirect immunofluorescence. Amacrine somata on both sides of the inner plexiform layer are labeled, as well as processes forming laminae within this layer. These results suggest that retinoic acid may play a functional role in the inner retina.