Prolactin as a promoter of initial progression of spontaneous mammary tumors in mice and lack of relationship to age

In a high mammary tumor strain of SHN virgin mice, the percent increase in the number of palpable mammary tumors during 3 weeks after the 1st tumor appearance was significantly retarded by ovariectomy and this retardation was prevented by pituitary grafting associated with the decrease and the increase in the circulating prolactin levels, respectively. A low mammary tumor strain of SLN virgin mice grafted with a single pituitary each at 2 and 5 months of ages developed mammary tumors 4 and 2 months after grafting (6 and 7 months of ages), respectively. However, there was no difference between groups in mammary tumor incidence at any month after mice in each group developed tumors first. Mammary tumor incidences of both groups were significantly higher than that of the untreated control at all ages examined. These findings have demonstrated that prolactin plays a key role in the initial progression of spontaneous mammary tumors of mice besides its prerequisite role in tumor development. They also suggest that there is no intrinsically age-related difference in prolactin effect on mammary tumorigenesis.     

Prostaglandin-sepharose: Application to the purification of bovine lung 15 (S) -hydroxyprostaglandin dehydrogenase

Prostaglandins E₁, F_1α and A₂ were covalently joined to the surface of Sepharose as carboxamide linkages. The insolubilized prostaglandins were shown to function effectively in the purification of 15(S) -hydroxyprostaglandin dehydrogenase.     

Nitrile hydratase of Pseudomonas chlororaphis B23. Purification and characterization

Nitrile hydratase of Pseudomonas chlororaphis B23 was completely stabilized by the addition of 22 mM n-butyric acid. The enzyme was purified from extracts of methacrylamide-induced cells of P. chlororaphis B23 in eight steps. At the last step, the enzyme was crystallized by adding ammonium sulfate. The crystallized enzyme appeared to be homogeneous from analysis by polyacrylamide gel electrophoresis, analytical ultracentrifuge, and double diffusion in agarose. The enzyme has a molecular mass of about 100 kDa and consists of four subunits identical in molecular mass (approximately 25 kDa). The enzyme contained approximately 4 mol iron/mol enzyme. The concentrated solution of highly purified nitrile hydratase had a pronounced greyish green color and exhibited a broad absorption in visible range with a absorption maxima at 720 nm. A loss of enzyme activity occurred in parallel with the disappearance of the absorption in the visible range under a variety of conditions. The enzyme catalyzed stoichiometrically the hydration of nitrile to amide, and no formation of acid and ammonia were detected. The enzyme was active toward various aliphatic nitriles, particularly, nitriles with 3-6 carbon atoms, e.g. propionitrile, n-butyronitrile, acrylonitrile and cyclopropyl cyanide, served as the most suitable substrates.     

Development of an embryogenic suspension culture of soybean (Glycine max Merrill.)

A rapidly growing, maintainable, embryogenic suspension culture of Glycine max L. Merrill. has been generated. The culture consisted almost entirely of clumps of proliferating globular embryos with very little nonembryogenic tissues. The number and size of somatic embryo clumps were used to quantify growth of embryogenic tissues under various conditions. Initiation and proliferation of this embryogenic suspension culture were dependent on the inoculum, method of subculture, and composition of the subculture medium. Twenty to 50 mg of highly embryogenic, early-staged soybean tissue were inoculated into 35 ml of liquid culture medium containing 5 mg 1^–1 2,4-D and either 15 mM glutamine or preferably 5 mM asparagine. Suspension cultures were subcultured at the same inoculum density every 4 weeks. The embryos matured and germinated following placement on solid media, resulting in consistent plant regeneration.     

Identification of alpha 2-macroglobulin as a carrier protein for IL-6

In this report we demonstrate that alpha 2-macroglobulin (alpha 2M) is a carrier protein for IL-6. IL-6 was found to bind plasma proteins and an immunoblot analysis revealed that the complex between IL-6 and plasma proteins contains alpha 2M. Furthermore, purified alpha 2M bound IL-6. alpha 2M did not inhibit IL-6 activity or its binding to homologous receptor. IL-6 bound to alpha 2M retained its biologic activity and became resistant to treatment with proteases, although free IL-6 was easily degraded. These findings indicate that alpha 2M plays an important role as a carrier protein for IL-6 in serum and makes IL-6 produced at the local inflammatory site available to lymphocytes, hepatocytes, and hematopoietic stem cells, resulting in the induction of the coordinate systemic host defense reactions, such as immune response, acute phase reaction, and hematopoiesis.     

Gene expression of metalloproteinase and its inhibitor in mesangial cells exposed to high glucose.

To clarify the roles of metalloproteinases and their inhibitor (TIMP) in diabetic glomerulopathy, we studied the effect of a high glucose concentration on the gene expression of metalloproteinase transin and TIMP as well as collagen type IV and laminin in cultured rat mesangial cells (MCs). In the high glucose group, collagen type IV, laminin, and TIMP mRNA levels were all elevated in a concentration-dependent manner, whereas transin expression was suppressed. Osmotic control of high glucose with mannitol selectively stimulated TIMP expression. We hypothesize that high glucose decreases matrix-degrading activity as well as increases matrix productivity in MCs.