Hormesis Shifts the No-Observed-Adverse-Effect Level (NOAEL).

Data from recent dose-response toxicological studies suggest that the no-observed-adverse-effect-level (NOAEL) may depend upon whether hormesis is present. A further examination of these data supports this hypothesis by showing that the NOAEL was greater for living units (organisms or cells) showing hormesis than for living units showing no hormesis. For example, some cancer tissue cells may exhibit hormetic responses to an anticancer drug while some other cancer tissue cells may not. These findings suggest that living units showing hormesis may also be less susceptible than living units not showing hormesis. However, these findings are preliminary and cannot be generalized or assumed to be a norm yet. New studies are needed to evaluate how NOAEL shifts depending on the occurrence of hormesis.

Optimization of on-chip bacterial culture conditions using the Box-Behnken design response surface methodology for faster drug susceptibility screening.

Optimized culture conditions are essential for the investigation of biological processes. In this work, on-chip optimization of bacterial culture conditions by combining microfluidics with the Box-Behnken design response surface methodology is presented. With this methodology, the effects of several cultivation variables and their interactions were investigated enabling very fast drug susceptibility screening. The proposed measurement protocol for the determination of minimum inhibitory concentration (MIC) consist of three steps: i) single factor experiments to determine the effect of pH, nutrient concentration, and temperature on the bacterial culture; ii) analyses of the relationship between variables and the effect of the individual variables by means of the Box-Behnken design and response surface methodology (BBD-RSM) optimization; and iii) bacterial susceptibility screening of drugs and drug combinations. BBD-RSM is efficient to determine the optimal growth conditions of bacteria species with a strongly reduced amount of required experiments. On top of that, these experiments can in principle all be performed at the same time, yielding significant time-savings. The found optimized culture conditions of E. coli were applied to determine the MIC values of the drugs penicillin-streptomycin and baicalein, and combinations of those. MIC values were obtained within 8-14 h, including the 6-8 h required to determine the optimal growth parameters. The microfluidic BBD-RSM method results in a significant time reduction compared to the standard 2-4 days required to determine MIC values and is, therefore, a potential alternative in the management of bacterial infections.

Susceptibility screening of highly pathogenic porcine reproductive and respiratory syndrome virus in several strains of minipigs / 中国比较医学杂志

Objective To screen strains of minipigs sensitive to highly pathogenic porcine reproductive and respiratory syndrome virus (HP-PRRSV) for evaluation of HP-PRRS live vaccine.Methods Lantang pigs, Juema, Bama and Wuzhishan ( white) minipigs were inoculated with virulent strain NVDC-JXA1 of PRRSV, and local binary hybrid pigs were used as control.The animals were continuously observed for 5 weeks on mental status, appetite, survival, etc.after inoculation of virus.The dead pigs were autopsied and the lung tissue samples were collected for detecting virus by RT-PCR.By the end of the experiment, serum of survival animals were collected for detecting PRRSV antibody by ELISA assay.Result The animals showed depression, anorexia, and other clinical signs and death in each group after inoculation.Meanwhile, the testing results were all positive in the RT-PCR and ELISA detection.Bama and Wuzhishan ( white) minipigs were the most sensitive to virulent strain NVDC-JXA1 of PRRSV regarding mortality rate.Conclusions Bama and Wuzhishan ( white) minipigs are sensitive to HP-PRRSV, and can be used for the inspection of HP-PRRS live vaccine.