Extent of breast cancer type 1 promoter methylation correlates with clinicopathological features in breast cancers.

AIM OF STUDY: The current meta-analysis investigated the correlation between breast cancer type 1 (BRCA1) promoter methylation and the clinicopathological features of breast cancer (BC). MATERIALS AND METHODS: An electronic literature search was performed to identify and select cohort studies, by employing stringent inclusion and exclusion criteria, for data relevant to promoter methylation of BRCA1 and BC. Statistical analysis of the extracted data was performed using comprehensive meta-analysis 2.0 software (CMA 2.0) (Biostat Inc., Englewood, New Jersey, USA). RESULTS: A total of 125 published studies were retrieved from the literature search, and finally, 18 cohort studies meeting our inclusion criteria were incorporated into our meta-analysis. The 18 studies contained a total of 3213 BC patients. Meta-analysis results revealed that BRCA1 promoter methylation in BC patients with high and moderately differentiated tumors (I-II) was significantly lower than patients with poorly-differentiation tumors (III) (odds ratio [OR] =0.450, 95% confidence interval [95% CI] =0.241-0.838, P = 0.012). BRCA1 promoter methylation in BC patients with lymph node (LN) metastasis was significantly higher than patients without LN metastasis (OR = 2.244, 95% CI = 1.278-3.940, P = 0.005). The results of ethnicity-based subgroup analysis showed a significant difference in histological grade of BC on Asians, LN metastasis of BC in Asians and Caucasians, subtypes of BC in Caucasians, and age at diagnosis of BC patients in Caucasians (all P < 0.05). CONCLUSIONS: Our meta-analysis revealed that BRCA1 promoter methylation status is linked to tumor grade and LN metastasis of BC.

Effect of Ca2+ and Mg2+ ions on surfactant solutions investigated by molecular dynamics simulation.

The effect of Ca(2+) and Mg(2+) on the H-bonding structure around the headgroup of the surfactants sodium dodecyl sulfate (SDS) and sodium dodecyl sulfonate (SDSn) in solution has been studied by molecular dynamics simulation. Our results show that binding between the headgroup of the surfactant and Ca(2+) or Mg(2+) is prevented by a stabilizing solvent-separated minimum formed in the potential of mean force (PMF) between the interacting ion-pair. Among the contributions to the PMF, the major repulsive interaction is due to the rearrangement of the hydration shell after the ions enter into the original H-bonding structure of water around the headgroup, leading to a decrease in the number of H-bonds and an increase in their lifetimes. In the second hydration shell around the headgroup, additional water molecules are bound to the headgroup oxygen atoms either directly or bridged by Ca(2+) and Mg(2+). The PMF shows that the energy barriers to ion-pairing between the headgroup and Ca(2+) and Mg(2+) in the SDSn system are higher than those in the SDS system, and the water coordination numbers for Ca(2+) or Mg(2+) in SDS solution are lower. This result indicates that SDS binds the ions easily compared with SDSn, and the ions have a strong effect on the original hydration structure. That is why sulfonate surfactants such as SDSn have better efficiency in salt solution with Ca(2+) and Mg(2+) for enhanced oil recovery.

New cyclodextrin derivative 6-O-(2-hydroxybutyl)-beta-cyclodextrin: preparation and its application in molecular binding and recognition.

A new soluble cyclodextrin derivative 6-O-(2-hydroxybutyl)-beta-cyclodextrin (6-HB-beta-CD) was prepared. Its molecular binding and recognition ability were investigated with the comparison of beta-cyclodextrin (beta-CD), 2-O-(2-hydroxypropyl)-beta-cyclodextrin (2-HP-beta-CD), 6-O-(2-hydroxypropyl)-beta-cyclodextrin (6-HP-beta-CD), and 2-O-(2-hydroxybutyl)-beta-cyclodextrin (2-HB-beta-CD). The relationship between the complex stability constants and the possible structures of inclusion compounds was discussed with the interaction of hosts and guests, including the weak hydrophobic interactions, the size/shape matching, the steric hindrance, and the hydrophilic property.

Characterization of floc size, strength and structure in various aluminum coagulants treatment.

Flocs generated in various aluminum coagulants treatment exhibit difference in size, strength and structure. The formation, breakage and re-formation of flocs were investigated by using a laser diffraction instrument (Malvern Mastersizer 2000, Malvern, UK). Different Al coagulants--conventional Al salt (AlCl(3)), polyaluminum chloride (PAC-1) and the purified polyaluminum chloride (PAC-2)--were investigated for the coagulation of humic acid (HA). The results showed the properties of HA flocs depend on which species of aluminum used. The monomeric and dimeric aluminum species (denoted as Al(mono)) formed the largest and strongest HA flocs with longest growth time. The HA flocs formed by Al(13)O(4)(OH)(24)(7+) (Al(13) for short) is the smallest and weakest. The properties of HA flocs made it possible to investigate the relationship between the flocs growth process and aluminum species.

Mesoscopic simulation study on a weakly charged block polyelectrolyte in aqueous solution.

In this paper, we use density functional theory to study the effect of the charge of solvophilic beads and concentration on the mesoscale structures of polyelectrolyte solution. The polyelectrolyte A6B12A6 was selected as the triblock polymer, and the solvophobic B blocks have no charges, while the solvophilic A blocks are charged. The simulation results showed: at higher concentration (above 50% systems), relatively small charges on the solvophilic block do not alter the bicontinuous phase inherent to uncharged solution, but at moderate concentrations (50% system), even though the charge per solvophilic bead is very small, the order lamellar structures become disturbed. [Figure: see text].