Incubation concentrations

The test system was considerably less sensitive to endosulfan when mouse ER, rather than human ER, was used to mediate (3-gal activity (Ramamoorthy et al. 1997). In similar assays, endosulfan at 10 jM had no effect on (3-gal activity in yeast Saccharomyces) transfected with either the human or rainbow trout ER (Andersen et al. 1999). In addition, no effect was observed on transcriptional activation of HeLa cells transfected with plasmids containing an estrogen receptor as a responsive element (Shelby et al. 1996). Endosulfan also did not induce transient reporter gene expression in MCF-7 human breast cancer cells at an incubation concentration of 2.5 pM (Andersen et al. 1999). Maximum endosulfan-induced ER-mediated luciferase reporter gene expression occurred in vitro in a T47D human breast adenocarcinoma cell line at approximately 10 pM, while 50% expression of luciferase occurred at about 5.9 pM the maximum expression was approximately 59% of the effect from exposure to 0.03 nM estradiol (0.00003 pM) (Legler et al. 1999). Luciferase expression from combined treatment with endosulfan and dieldrin was additive over concentrations ranging from 3 to 8 pM. 

The data of figure 6a is for an incubation concentration of 150 pg ml-1 of the respective polymers, but is essentially unchanged for the lower (10 pg ml-1) polymer concentrations, and also following replacement of the solution by pure electrolyte. 

Fig. 2.26 Plot of the DBQ (Drug, D)/CMVP A144L (Protein, P) molar ratios for the incubated concentrations as a function of the non-covalently bound concentrations as determined in the titration study of the GPC spin column eluates assayed by ESI-MS (see Table 2.5). The shape of the curve indicates that up to three drugs bind non-covalently and non-specifically to CMVP A144L.

Incubation volume = 100 xl except "a" which was 25 pi Heads from resting stage females and males were extracted in Aedes saline on ice, centrifuged at 8,0l g for 5 minutes and the supernatant used in incubations. Concentration of head equivalent/pl was 0.2. Average ecdysteroid produced is expressed as the mean of 4 determinations SEM. 

In later TEM studies by Ghadially et al. (48), a lower concentration of cisplatin (30 (xM) was incubated in HeLa and human lymphoblastoid (RPMI 6410) cells for periods that ranged from 1 hour to 4 days. No intracellular platinum was detected in either cell line. However, similar incubations with platinum(II)-uracil resulted in development of lysosome-like bodies in the cytosol, which are referred to as platinosomes, that contain electron dense species identified by X-ray analysis as platinum (48). In a related study, similar concentrations of cisplatin were injected into rabbit knee joints and incubated for several days. Again, no platinum was detected in the intracellular or extracellular compartments of the synovial cells, whereas platinum was observed to accumulate only in the platinosomes after platinum-uracil incubation (49). This set of studies highlights the effect of incubation concentrations of the drug on the cellular distribution results, as well as, drawing attention to the uptake of some platinum(II) complexes in cytoplasmic organelles. 

Fluorescence microscopy uniquely allows for real time, three-dimensional tracking of drugs in live cells at low incubation concentrations. When employed in conjunction with tools such as pathway inhibitors, this technique can elucidate drug trafficking pathways and reveal the roles of intracellular components in the drug action. 

SRIXE is a powerful technique that can map the distribution of platinum with very high sensitivity and at low incubation concentrations of the unmodified platinum drug. With future improvements to its resolving power, this technique has the potential to obtain unprecedented information on the distribution of both endogenous and exogenous elements at a sub-cellular level. 

Substrate, nitrocefin after 5 min pre-incubation concentration of inhibitor, 5.0 /ig/ml for Gram-negative bacteria and 1.0 //g/ml for S.a. Enzyme classification based on Richmond-Sykes. For abbreviations, see footnote to Table 6.1. 

Triple quadrupole mass spectrometers can perform tandem mass scan experiments in various modes including product ion (MS/MS), precursor ion, and neutral loss scan and SRM experiments, but they cannot be used for sequential MS" experiments. The high sensitivity and specificity, in the SRM mode, have made triple quadrupole mass spectrometers a logical choice for metabolic stability experiments performed at relevant substrate concentrations. Despite the sensitivity of the triple quadrupole mass spectrometers, when an NCE or an NCE series exhibit unacceptable PK properties, metabolite identification studies are often initiated as follow-up studies in a separate set of experiments using incubation concentrations higher than the Km of an NCE. Incubations at higher concentrations are required because conventional metabolite identification experiments required operation of the triple quadrupole mass spectrometer in the full-scan mode, which results in poor duty cycle and diminished sensitivity [287,288],... 

Concenlranon dial reduced the viral litre by 50% after incubation Concentration that gave a 50% decrease in host cell as measured by XTT assay. 

Immobilization by entrapment of P. laminosum When P. laminosum cells were entr ped in PU foams according to Brouers et al. (3), complete loss of viability was observed after 2-3 days of immobilization. Consequently, in an attempt to overcome the toxicity problems, different parameters were modified (temperature of polymerisation, prepolymer culture medium ratio, polymerisation time, light intensity, temperature of incubation, concentration of initial cell suspension, etc.) without any success. In all cases, high toxicity was observed which lead to a rapid death of the immobilized cells. It seems that this toxicity originates in the polymerisation reaction due to a possible release of toxic compounds and local increase of temperature and pressure. 

Noticeably, many studies indicated that the viability of cells treated with UCNPs mainly depended on the incubation time and concentration. For example, as reported by Zhang et al.the cell viability of skeletal myoblasts and marrow-derived stem cells significantly decreased with the increase of the incubation concentration of the NaYF4 Yb,Er( )Si02 nanocomposite from 1 to 100 pg mL When the incubation concentration reached 100 pg mL , it was found that approximately 63% of these eells were viable. 

Metabolism Metabolic stability (see Section 6.3.2.1) Metabolic soft-spot identification (see Table 6.10) Reactive metabolites (see Table 6.10) Assessing in vitro metabolic liabilities by drug-metabohsm enzymes such as CYP Predicting in vivo clearance Assay ° Liver microsomes from various species ° NADPH as co-factor ° 0.5-5 i,M incubation concentration Analysis ° PPT followed by LC-MS/MS or onhne SPE-MS/MS... 

Figures 1 and 2 show the typical results of our experiments. Based on the Derjaguin approximations, the data obtained from independent experiments (and different contact positions) are summarized as a plot of F/R (with F and R being the force and mean radius of curvature of mica surfaces, rspectively) against the separation between the mica substrates D. The measurements were carried out in toluene at 32 C. The incubation concentrations for both homo-PS (PS233) and PVP-PS (60-60 and 60-90) samples in the apparatus were approximately 3 pg/ml.

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