Relation between the permeability and the degree of coil overlap of polymer in the bulk state

Based on the expression of the index of coil interpenetration (i.e.,the degree of coil overlap,ξ_b) of amorphous polymers in the bulk state proposed by Qian,theξ_b was rewritten asξ_b=ρ_b[η]_θ/1.66 via Flory's intrinsic viscosity equation at them conditions.Theξ_b ofpoly (vinyl chloride) (PVC) dense membranes with different molecular weights and cellulose diacetate (CA) dense membranes prepared using different solvents were determined.The permeability,permeation coefficient (P) of nitrogen and permeation flux (J) of liquid through both membranes,respectively,was measured.P and J decreased exponentially with increasingξ_b for PVC and CA membranes were revealed.     

Akt is involved in the inhibition of cell proliferation by EGF

Axin is a negative regulator of the Wnt/beta-catenin pathway and is involved in the regulation of axis formation and proliferation. Involvement of Axin in the regulation of other signaling pathways is poorly understood. In this study, we investigated the involvement of Akt in growth regulation by Axin in L929 fibroblasts stimulated by EGF. Akt activity was increased by EGF treatment and Ras activation, respectively. Both the EGF- and Ras-induced Akt activations were abolished by Axin induction, as revealed by both Western blot and immunocytochemical analyses. The proliferation and Akt activation induced by EGF were decreased by Axin induction, and the effects of EGF were abolished by treatment of an Akt-specific inhibitor. Therefore, Axin inhibits EGF-induced proliferation of L929 fibroblasts by blocking Akt activation.     

A point mutant of apolipoprotein A-I, V156K, exhibited potent anti-oxidant and anti-atherosclerotic activity in hypercholesterolemic C57BL/6 mice

In our previous study, two point mutants of apolipoprotein A-I, designated V156K and A158E, revealed peculiar characteristics in their lipid-free and lipid-bound states. In order to determine the putative therapeutic potential of these mutants, several in vitro and in vivo evaluations were conducted. In the lipid-free state, V156K showed more profound antioxidant activity against LDL oxidation than did the wildtype (WT) or A158E variants in an in vitro assay. In the lipid-bound state, V156K-rHDL showed an enhanced cholesterol delivery activity to HepG2 cells in a time-dependent manner, as compared to WT-rHDL, A158E-rHDL, and R173C-rHDL. We assessed the physiological activities of the mutants in circulation, using hypercholesterolemic mice (C57BL6/J). Palmitoyloleoyl phosphatidylcholine (POPC)-rHDL preparations containing each of the apoA-I variants were injected into the mice at a dosage of 30 mg of apoA-I/kg of body weight. Forty eight hours after injection, the sera of the V156K-rHDL injected group showed the most potent antioxidant abilities in the ferric acid removal assay. The V156K-rHDL- or R173C-rHDL-injected mice showed no atherosclerotic lesions and manifested striking increases in their serum apo-E levels, as compared to the mice injected with WT-rHDL or A158E-rHDL. In conclusion, V156K-rHDL exhibited the most pronounced antioxidant activity and anti-atherosclerotic activity, both in vitro and in vivo. These results support the notion that HDL-therapy may prove beneficial due to its capacity to induce accelerated cholesterol excretion, as well as its enhanced antioxidant and anti-inflammatory effects and lesion regression effect.     

Cytochrome P450 1A1 (CYP1A1) polymorphisms and breast cancer risk in Korean women

Cytochrome P450 1A1 (CYP1A1) is involved in the 2-hydroxylation of estrogen, the hormone that plays a critical role in the etiology of breast carcinoma. We evaluated the associations between two CYP1A1 polymorphisms [MspI (rs4646903); Ile462Val (rs1048943)] and breast cancer in a multicenter case-control study of 513 breast cancer cases and 447 controls in Korea. Women carrying the T allele of the CYP1A1 MspI polymorphism were found to have a 1.72-fold (95% CI 1.11-2.68) greater risk of developing breast cancer. No association was found between any CYP1A1 Ile462Val polymorphism and breast cancer. Haplotype analysis of the two loci showed that the CA haplotype was associated with the lowest risk of breast cancer, and CA/CA diplotypes were associated with a lower risk of breast cancer [OR=0.28 (0.13-0.61)] than others/others diplotypes. Moreover, this reduced risk was more pronounced among women with a lower body mass index (BMI) [OR=0.18 (0.06-0.58)] or with a shorter lifetime exposure to estrogen [OR=0.23 (0.07-0.81)]. The results obtained suggest that the CYP1A1 MspI polymorphisms could affect susceptibility to breast cancer.     

An inhibitory compound against the interaction between G alpha(s) and the third intracellular loop region of serotonin receptor subtype 6 (5-HT6) disrupts the signaling pathway of 5-HT6

Serotonin receptor subtype 6 (5-HT(6)) is a neurotransmitter receptor, which is involved in various brain functions such as memory and mood. It mediates signaling via the interaction with a stimulatory G-protein. Especially, the third intracellular loop (iL3) of 5-HT(6) and the alpha subunit of stimulatory G protein (G alpha(s)) are responsible for the signaling process of 5-HT(6). Chemical compounds that could inhibit the interaction between the iL3 region of 5-HT(6) and G alpha(s) were screened from a chemical library consisted of 5,600 synthetic compounds. One of the identified compounds bound to G alpha(s) and effectively blocked the interaction between G alpha(s) and the iL3 region of 5-HT(6). The identified compound was further shown to reduce the serotonin-induced accumulation of cAMP in 293T cells transformed with 5-HT(6) cDNA. It also lowered the Ca(2+) efflux induced by serotonin in cells expressing 5-HT(6) and chimeric G alpha(s5/q). These results indicate that the interaction between the iL3 of 5-HT(6) and G alpha(s) can be exploited for screening of regulatory compounds against the signaling pathway of 5-HT(6).     

Electrochemical synthesis of cobalt hydroxide films with tunable interlayer spacings

An electrochemical synthetic condition is developed to produce cobalt hydroxide films with significantly increased basal spacings (d(001)>or= 25.0 A) by incorporating anionic surfactants (i.e. sodium dodecyl sulfate and 1-hexadecanesulfonate) into the interlayer regions via electrodeposition.     

One-pot synthetic route to polymer-silica assembled capsule encased with nonionic drug molecule

A novel combinational drug delivery system, in which drug molecules could be dually encapsulated by soft (polymer) and hard (inorganic) vehicles has been successfully prepared via a simple one-pot synthesis; its improved chemotherapeutic efficacy has been verified through in vitro experiments.     

Silicon-phthalocyanine-cored fullerene dendrimers: synthesis and prolonged charge-separated states with dendrimer generations

Silicon-phthalocyanine-cored fullerodendrimers with up to eight fullerene substituents (SiPc-n C(60); n=2, 4, and 8) have been synthesized. Photophysical properties of newly synthesized SiPc-n C(60) have been investigated by time-resolved fluorescence and transient absorption analysis with pulsed laser light. Laser photolysis measurements suggest the occurrence of a charge-separation process from (1)SiPc* to the C(60) subunits. The nanosecond transient absorption spectra in the near-IR region indicate that the lifetimes of the formed radical ion pairs are prolonged on the order of SiPc-8 C(60)>SiPc-4 C(60)>SiPc-2 C(60), which may be related to the electron migration among the C(60) subunits. The usefulness of SiPc-n C(60) as light-harvesting systems, evaluated as a ratio of the rates of charge recombination to those of charge separation, increases markedly with the dendrimer generation.     

A new chromone, 11-hydroxy-sec-O-glucosylhamaudol from Ostericum koreanum

From the ethyl acetate fraction of the roots of Ostericum koreanum, a new chromone, 11-hydroxy-sec-O-glucosylhamaudol (1) along with the known compounds: four chromones, three coumarins, six phenolic compounds, and three quinic acids were isolated. These compounds were assessed for antioxidant activities in the DPPH radical and superoxide anion radical scavenging assay systems. Among isolates, 4-(2-hydroxy-vinyl)-benzene-1,2-diol (12) showed the most potent DPPH radical scavenging activity (IC(50)=4.80+/-0.62 mug/ml) and superoxide anion radical scavenging activity (IC(50)=11.05+/-0.83 microg/ml) in the xanthine/xanthine oxidase system. The antioxidant activities of 12 were comparable to those of quercetin and luteolin.