The role of the duodenum in adaptive changes in sucrose digestion in the small intestine of chicks

In two experimental series in situ applying perfusion technique, and in vitro, the role of the duodenum in adaptation of sucrose digestion was investigated in the proximal, medial and distal parts of the chick small intestine. No adaptive changes occurred in hydrolysis and carbohydrate transport if the pancreo-duodenal complex was isolated from the lower parts. It is suggested that on feeding with sucrose, factors arise in the duodenal mucosa causing adaptive changes in sucrase activity of the small intestine.     

Potential therapeutic and diagnostic applications of the growth of testicular cancer in soft agar

Sixteen histologically documented testicular cancer specimens obtained at diagnostic procedures following induction chemotherapy with cis-platinum containing regimens were cloned in soft agar. Seven (44%) of the specimens cultured formed colonies with a mean cloning efficiency of .021%. Colony formation was observed with all the common histologic subtypes of testicular cancer (seminoma, embryonal carcinoma, choriocarcinoma and mixed tumors). In vitro drug sensitivity tests were performed using cis-platinum, vinblastine and VP-16. Three of four specimens demonstrated a decrease in colony formation to less than 50% of controls after a 1 h exposure to VP-16 at 300 micrograms/ml. Two of these patients had a response to treatment with a VP-16 based salvage regimen. Immunoperoxidase staining of the colonies for alpha feto protein and human chorionic gonadotropin were correlated with the serum levels of these tumor markers determined at the time the specimen was obtained. In three instances the same markers were elevated in the serum as detected within cells which formed the colonies; however, in two other cases the marker(s) that was elevated in the serum was not expressed in the colonies. In one case a biopsy of a residual retroperitoneal mass following chemotherapy histologically was a teratoma, but it formed colonies in the assay which stained positive for alpha feto protein. This patient subsequently developed an elevated serum alpha feto protein. These studies have demonstrated that (a) testicular cancer can be cloned directly in soft agar; (b) a heterogeneous tumor cell population exists in metastatic testicular cancer specimens; and (c) a dose response exists for VP-16 in relapsed testicular cancer which suggests that increasing the dose of VP-16 may be clinically beneficial.     

Determination of cross relaxation rates by 3D NOE-NOE spectroscopy

Summary A method for quantitative determination of cross-relaxation rates of macromolecules in solution is developed. The method is based on the analysis of the intensities of cross peaks in 3D NOE-NOE spectra. The linear combination of the intensities of 3D peaks (spin-diffusion peaks, back-transfer peaks) results in an expression directly proportional to the cross-relaxation rate. The proposed approach allows to determine interproton distances in macromolecules more accurately.