DMSO arrested hybridoma cells for enhanced antibody production / 生物工程学报

Dimethyl sulfoxide (DMSO), a well-known differentiation inducer in several myeloid cells, induces G1 phase arrest in many cell lines. In this study, we investigated the possibility of using DMSO to arrest H18 hybridoma cells to the G1 phase and monitor whether the arrest improves antibody production. We showed that DMSO in concentration ranging between 0.3% and 0.6% efficiently arrested H18 hybridoma cells in G1 phase. In our experiment, > 80% of cells grown for 36h in presence of the 0.6% DMSO were arrested in G1. Furthermore, expression levels of P27 were up-regulated tow fold during the G1 phase. Higher concentration of DMSO at 0.9% leads to cytotoxicity. Herein we show a simple way, a two-stage process for antibody production, which consists of a proliferation phase leading to the desired cell density, followed by an extended production phase during which the cells remain at G1 phase. Our observation that the addition of DMSO results in increase antibody production is of significance in further use of hybridoma cells in high density large scale cell culture.

The role of vagal innervation in the variability of heart beat / 生理学报

To determine the role of vagi in heart rate variability, conscious rabbits were employed and electrocardiogram was recorded under conditions of bilateral vagi intact, unilateral vagotomy, and bilateral vagotomy. The variability of RR intervals (RRI) was analyzed using power spectrum and approximate entropy (ApEn). The results showed that the values of high frequency power (HF) component, low frequency power (LF) component and ApEn in animals with bilateral vagi intact were the highest, but the LF/HF ratio was the lowest; unilateral vagotomy decreased ApEn, right vagotomy increased LF/HF ratio but left vagotomy did not; the LF/HF ratio increased while ApEn decreased significantly in animals with bilateral vagotomy. It is suggested that the variability of RRI is mainly regulated by the vagi and the role of right vagi is more important than that of the left. When measuring heart rate variability, the results obtained with conventional method are consistent with those with nonlinear method.