Pathway of inactivation of cholecystokinin octapeptide (CCK-8) by synaptosomal fractions

Cholecystokinin octapeptide (CCK-8) was degraded by peptidases present in intact synaptosomes isolated from rat cortex and hypothalamus. Most of the degrading activity was present in the cytoplasmic fraction although a small amount (7%) was membrane-bound. Products of the degradation were isolated by HPLC and characterized by amino acid analysis. The Met³-Gly⁴ bond was the main primary site of cleavage giving rise to Asp-Tyr(SO₃H)-Met and Gly-Trp-Met-Asp-Phe-NH₂. These products appeared to be further degraded by sequential removal of amino-terminal residues. The Asp¹-Tyr² and Asp⁷-Phe⁸ bonds were also sites of cleavage. p-Chloromercuribenzoate was the most effective inhibitor (90% inhibition) of CCK-8 degradation by synaptosomal peptidases at the concentrations tested.This peptidase activity in synaptosomes may be important in the regulation of levels of the neuropeptide CCK-8 at the synapse. Identification of the sites of cleavage of CCK-8 on incubation with synaptosomes will assist in the isolation and characterization of the enzymes involved.     

Proposed follow up programme after curative resection for lower third oesophageal cancer

Cyclins are indispensable elements of the cell cycle and derangement of their function can lead to cancer formation. Recent studies have also revealed more mechanisms through which cyclins can express their oncogenic potential. This review focuses on the aberrant expression of G1/S cyclins and especially cyclin D and cyclin E; the pathways through which they lead to tumour formation and their involvement in different types of cancer. These elements indicate the mechanisms that could act as targets for cancer therapy.     

Improvement of mammalian cell culture performance through surfactant enabled concentrated feed media

The design of basal and feed media in mammalian cell culture is paramount towards ensuring acceptable upstream process performance in various operation modes, especially fed‐batch culture. Mammalian cell culture media designs have evolved from the classical formulations designed by Eagle and Ham, to today's formulations designed from continuous improvement and statistical frameworks. Feed media is especially important for ensuring robust cell growth, productivity, and ensuring the product quality of recombinant therapeutics are within acceptable ranges. Numerous studies have highlighted the benefit of various media designs, supplements, and feed addition strategies towards the resulting cell culture process. In this work we highlight the use of a top‐down level approach towards feed media design enabled by the use of select surfactants for the targeted enrichment of a chemically defined feed media. The use of the enriched media was able to improve product titers at g/L levels, without adversely impacting the growth of multiple Chinese Hamster Ovary cell lines or the product quality of multiple recombinant antibodies. © 2013 American Institute of Chemical Engineers Biotechnol. Prog., 29:1023–1033, 2013