Search

Formalin instillation into canine bladders was followed by serial radiographic and histologic evaluation. A generalized slough of epithelial tissue was seen with the deposition of an amorphous substance. Telangiectasia resulted in moderate bleeding. No ureterovesical junction obstruction was seen and reflux occurring in 60 per cent of the animals reverted to normal. Correlation with clinical experience is made.

A case of retroperitoneal fibrosis associated with retroperitoneal abscess is reported. The causation and treatment of idiopathic and nonidiopathic retroperitoneal fibrosis are discussed.

Cleavage-arrested embryos of the ascidian Ciona intestinalis were able to differentiate two tissue-specific enzymes-muscle acetylcholinesterase (EC 3.1.1.7) and brain pigment cell tyrosinase (EC 1.10.3.1). Cytochalasin B, colchicine, Colcemid, and podophyllotoxin were used as cleavage inhibitors at early embryonic stages up to the 64-cell stage. Only certain cells in the cleavage-arrested embryos developed these histochemically detectable enzymes, and this ability followed the cell lineage patterns for the two tissues. This result implies the presence of specific positional information in the egg cytoplasm that is differentially segregated during cleavage. There were distinct and separate puromycin and actinomycin D sensitivity periods for the occurrence of each enzyme during development of both normal and cleavage-arrested embryos. The segregated information is apparently neither the enzyme proteins nor RNA templates for enzyme synthesis, but is probably concerned with activation of appropriate genes.

1. The use of specific cholinesterase inhibitors and substrates demonstrated that the enzyme activity in Ciona intestinalis larvae is an acetylcholinesterase. 2. Eggs treated with eserine sulfate (an acetylcholinesterase inhibitor) for one hour prior to fertilization developed into larvae with defective muscular movements and greatly reduced levels of acetylcholinesterase activity. 3. Two kinds of experiments show that this reduced enzyme activity was caused by the retention of eserine and not by inhibition of acetylcholinesterase synthesis. Homogenates of embryos from eserine-treated eggs inhibit acetylcholinesterase activity when mixed with homogenates of control embryos. Full enzyme activity in homogenates of the experimental embryos could be recovered by dialysis.