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R Augustine

Publications and source records attributed to R Augustine.

4 recordsLinked to original sources

Calcium-dependent phosphorylation of histone H3 in butyrate-treated HeLa cells.

Ca2+ is prominant in the control of cell proliferation and function. However, the biochemical mechanism(s) mediating its effects on nuclear events is unknown. We report here that Ca2+, at physiological concentrations, stimulates the phosphorylation of histone H3 by an endogenous protein kinase in HeLa cell nuclei. Also, pretreatment of cells with Na butyrate, which increases histone acetylation, selectively increases the susceptability of histone H3 to phosphorylation by the protein kinase. Our results reveal a potential link between histone H3 acetylation and phosphorylation, modifications which are thought to have important effects on chromatin structure and function and suggest a possible mechanism whereby stimuli at the cell surface (such as hormones, mitogens and drugs) may influence biochemical events at the nuclear level; changes in the intracellular Ca2+ concentration may influence the phosphorylation of chromosomal proteins, mediated by Ca2+ -dependent kinases in th nucleus.

Acetylation↗

Aztreonam for injection (lyophilized): development of an automated solution batching process utilizing volumetric powder feeders.

As part of a commitment to fully automate the manufacture of a lyophilized dosage form of Azactam (Aztreonam for Injection), an automated solution batching procedure was developed. The lyophilization process requires solution batching of Aztreonam and L-arginine, the two constituents of the product. To avoid preblending of aztreonam and L-arginine prior to dissolution, a batching process was developed which makes use of two separate volumetric powder feeders. In conjunction with a feedback pH control system, these powder feeders provided for (a) a faster batching process, (b) a tight control of solution pH during batching, (c) a failsafe system to prevent operator error and equipment malfunction. Data are presented correlating bulk densities of various powders with feeder output along with solution pH profiles determined using the manual mode and the automated feedback pH control system.

Automation↗