After UV-irradiation, no difference in the survival curves was observed among cell lines derived from LEC strain (LEC) rats and WKAH strain (WKAH) rats. The dose-response curves for inhibition of DNA synthesis in WKAH-derived cells showed a sharp decline at lower doses and a mild decline at higher doses of UV-rays. In contrast, the dose-response curves in LEC-derived cell lines had no sharp com...

Physiological and pharmacological studies of hormones, drugs, and neurotransmitters often generate families of sigmoidal dose-response curves. Optimally efficient data analysis should involve simultaneous description of all curves, rather than fitting each one individually. We have developed a general computerized method to describe the dose-response curves in terms of basal and maximal respons...

Dose- and time-response curves were combined to assess the potential of the comet assay in radiation biodosimetry. The neutral comet assay was used to detect DNA double-strand breaks in lymphocytes caused by γ-ray irradiation. A clear dose-response relationship with DNA double-strand breaks using the comet assay was found at different times after irradiation (p < 0.001). A time-response relatio...

We describe a novel algorithm, Grid algorithm, and the corresponding computer program for high throughput fitting of dose-response curves that are described by the four-parameter symmetric logistic dose-response model. The Grid algorithm searches through all points in a grid of four dimensions (parameters) and finds the optimum one that corresponds to the best fit. Using simulated dose-response...

- verapamil produces a sustained contraction in isolated biventer-cervicis muscle of chickens between 2-8 days old. from cumulative dose-response curves, ed50 of was calculated for this effect of verapamil. when isolated chicken biventer-cervicis muscle was electrically stimulated, verapamil had no effect on twitch contractures but increased the base line tone of the muscle. glycerol treatment ...

Drug efficacy does not always increase sigmoidally with concentration, which has puzzled the community for decades. Unlike standard sigmoidal curves, bell-shaped concentration-response curves suggest more complex biological effects, such as multiple-binding sites or multiple targets. Here, we investigate a physical property-based mechanism for bell-shaped curves. Beginning with the observation ...

the effects of hydroalcoholic extract of peganum harmala seeds (eps) on spontaneous rhythmic contractions of isolated rat uterine was investigated in this study. eps was tested on the isolated uterus and endometrium free (i.e. stripped myometrium) preparations. eps was found to exhibit significant spontaneous contractions of the uterus and stripped myometrium relative to the solvent control. af...