The efficacy of pharmacological perturbation to the signaling transduction network depends on the network topology. However, whether and how signaling dynamics mediated by crosstalk contributes to the drug resistance are not fully understood and remain to be systematically explored. In this study, motivated by a realistic signaling network linked by crosstalk between EGF/EGFR/Ras/MEK/ERK pathwa...

By the time-kill curve method, a vancomycin-rifampin combination showed neither synergism nor antagonism against 43 of 48 strains of enterococci. Antagonism was demonstrated against five strains.

The purpose of this study was to demonstrate that in vitro cell culture systems could serve a useful purpose in providing some guidelines in formulating drug schedules for combination cancer chemotherapy in the clinic. Using monolayer cultures of Chinese hamster ovary cells as the test system, we screened the combinations of 1-beta-D-arabinofuranosylcytosine (ara-C) + adriamycin, ara-C + 3,6 - ...

An experiment was designed to determine the effect of radiation dosage on the synergism between radiation and estrogen in the production of mammary cancer. Female A x C rats had their left mammary chain exposed to graded doses of X-radiation while under anesthetic with urethan or sodium pentobarbital. The rats had previously been hysterectomized and exposed to estrogen by implantation with chol...

Combinations of gentamicin with cefotaxime, moxalactam, and ceftazidime were tested against 43 bacterial strains, most of them blood isolates. With an interaction index of less than or equal to 0.5 as borderline, synergism was demonstrated against 30 to 40% of the strains by the fractional inhibitory concentration index and against 50 to 70% by the fractional bactericidal concentration index. T...

Earlier studies have shown that inhibition of aggregation of washed platelets (WP) by NO was enhanced almost 100-fold by H2O2. In the present study, the interactions of H2O2 with nitrosothiols, the influence of the presence of plasma and the mechanism of the synergism were investigated. H2O2 strongly enhanced the inhibitory effects of S-nitrosoglutathione (GSNO) on thrombin-induced aggregation ...

This brief article focuses on two aims: i) To investigate the in vitro pharmaco-dynamic interactions of combining synthetic potent microtubule targeting anticancer agent, Fludelone (FD) with cyto-protective agent, Panaxytriol (PXT) derived from Panax ginseng, and ii) To illustrate step-by-step operation for conducting two-drug combination in vitro using the combination index method, in terms of...

The effect of mixed mutagen exposures on the rate and type of induced mutants was studied in the L5178Y/TK+/-----TK-/- mouse lymphoma cell mutagenicity assay. In this assay, exposure to ethyl methanesulfonate (EMS) results in more mutants that form large colonies than small colonies. Exposure to methyl methanesulfonate (MMS) results in more mutants that form small colonies than large colonies. ...

Understanding the effects of exposure to chemical mixtures is a common goal of pharmacology and ecotoxicology. In risk assessment-oriented ecotoxicology, defining the scope of application of additivity models has received utmost attention in the last 20 years, since they potentially allow one to predict the effect of any chemical mixture relying on individual chemical information only. The gold...

Lignocellulosic biomass (LCB) is an attractive source of carbon for the production of sugars and other chemicals. Due to its inherent complexity and heterogeneity, efficient biodegradation requires the actions of different types of hydrolytic enzymes. In nature, complex microbial communities that work efficiently and often synergistically accomplish degradation. Studying such synergisms in LCB ...