d,l-Camphor was detected as a new inducer of hydroxylase in the liver musomes of female mice. After a 2-day inhalation of d,l-camphor, cyt. P-450 and the ethylumbelliferone dealkylase were increased by 250 per cent and the NADPH-cyt. P-450 reductase by 350 per cent. The product [NADPH-cyt. P-450 reductase activity × cyt. P450 concentration] was shown to be a suitable reference parameter for the ethylumbelliferone dealkylase activity in the liver musomes during the treatment with four different inducers. The relative dealkylase activity Q was much decreased during inhalation of cyclohexane or d,l-camphor.Obviously these two inducers preferably enhanced cyt. P-450 species with a low dealkylase activity. The Q-values were reproducible. Q was increased by 100 per cent during induction of a MC-sensitive mouse strain with 3-methylcholanthrene, but it was only moderately decreased by induction with phenobarbital. Corresponding to this, methylcholanthrene is known to selectively induce a cyt. P-448 with high dealkylase activity whereas phenobarbital is known to change the hydroxylase specificity in the liver musomes not very much. 相似文献
Semitelechelic (ω‐), telechelic (α,ω‐), as well as 3‐ and 12‐arm star polyisoprenes (PI), end‐functionalized with the same dimethylamino group, were synthesized by anionic polymerization high vacuum techniques, using 3‐dimethylaminopropyllithium as initiator and chlorosilanes as linking agents. The dimethylamino groups were transformed to phosphatidylcholine analogues through reaction with 2‐ethoxy‐2‐oxo‐1,3,2‐dioxaphospholane. The association behavior of the phosphoro‐zwitterionic PI (PZw‐PI) was studied in cyclohexane by low angle laser light scattering, viscometry, and dynamic light scattering. The linear PZw‐PIs present relatively low weight‐average degree of association (Nw: 2–6), as compared with the corresponding sulfo‐zwitterionic PI (Nw: 10–45). The Nw values decrease with increasing molecular weight of the PI. In the case of the star PZw‐PI, the multiple intermolecular associations lead to the formation of gels, which break down by addition of a small amount of 1‐heptanol. In very dilute solutions and for high arm molecular weight stars, intramolecular dominates over intermolecular association.
A simple expression for the composition dependence of the Flory‐Huggins interaction parameter of polymer/solvent systems reported earlier is used to model the demixing of polymer solutions into two liquid phases. To this end, the system specific parameters ζ and ν of that approach are calculated as a function of temperature using the thermodynamic expressions resulting for the critical conditions on one side and from experimentally determined critical data for polymers of different molar mass on the other side. By means of data reported for the system cyclohexane/polystyrene it is demonstrated that binodal and spinodal lines are very accurately modeled at low temperatures (UCSTs) and at high temperatures (LCSTs). The parameters obtained from the demixing behavior match well with that calculated from the composition dependence of the vapor pressure at temperatures where the components are completely miscible. Information on the phase separation of the system trans‐decalin/polystyrene for different molecular weights and at different elevated pressures is used to show that the approach is also apt to model pressure influences. The thus obtained ζ(T;p) and ν(T;p) enable the prediction of the (endothermal) theta temperature of the system as a function of pressure in quantitative agreement with the data directly obtained from light scattering measurements with dilute solutions.
Novel 1,1-disubstituted cyclohexane-1-carboxamides 6a-h , 7a-e , and 8a-b were designed and synthesized as apoptotic inducers. Cytotoxicity test revealed that some compounds have strong to moderate effect, while others displayed weak action against different cancer cell lines including, MCF-7, HepG2, A549, and HTC-116. A549 carcinoma cell line exhibited higher sensitivity toward all synthesized candidates especially compounds 6a and 8a which offered the lowest IC50 values 3.03 and 5.21 μM, respectively, relative to the positive control doxorubicin with IC50 value of 3.01 μM. Compared to doxorubicin treatment, compounds 6a and 8a induced caspases-3, -8, and -9 activities and G2/M growth arrest in A549 carcinoma cell line. The expression levels of p53 (tumor suppressor protein that in humans is encoded by the TP53 gene), Bax (apoptosis regulator protein in humans that is encoded by bax gene), and the Bax/Bcl-2 ratio were all higher than those in doxorubicin-treated cells (Bcl-2, B-cell lymphoma 2, encoded in humans by the Bcl-2 gene). Additionally, compounds 6a and 8a appeared to exhibit higher selectivity against MCF-10 human breast normal cell line. The synthesized congeners could be considered as potent apoptotic inducers interfering with extrinsic and intrinsic apoptotic pathways. Moreover, compound 6a was able to form complex with zinc ions as indicated by UV spectrophotometry which revealed its ability for being caspase activator. Molecular docking studies expected the interactions and binding modes of the synthesized inhibitors in the caspase-3 active site. 相似文献