Measurement of bisphenol A and bisphenol B levels in human blood sera from healthy and endometriotic women

A sensitive HPLC method with fluorescence detection was developed for the determination of bisphenol A (BPA) and bisphenol B (BPB) in human blood serum. The detection limits of the method were 0.18 and 0.20 ng/mL for BPA and BPB, respectively. A single‐step liquid–liquid extraction was used for the pre‐treatment of serum samples. The recoveries of BPA and BPB spiked to sera were 85.6 and 87.7%, respectively. The analyses of sera from both healthy and endometriotic women emphasized the absence of bisphenols in all the control cases (11 women), whereas BPA was found in 30 sera (51.7%) and BPB was found in 16 sera (27.6%) in the group of 58 patients with endometriosis; in nine of such sera BPA and BPB were present simultaneously. Only relatively to the sera quantitated, BPA concentrations ranged from 0.79 to 7.12 ng/mL (mean concentration 2.91 ± 1.74 ng/mL), whereas BPB concentrations ranged from 0.88 to 11.94 ng/mL (mean concentration 5.15 ± 4.16 ng/mL). Therefore, the presence of at least one of the two bisphenols was verified in a percentage as high as 63.8% in the sera from endometriotic women, suggesting the existence of a relationship between endometriosis and BPA and/or BPB exposure. Indeed, it is well known that bisphenols can work as xenoestrogens, owing to their structural similarity to natural and synthetic estrogens (e.g. estradiol and dietilstilbestrol). However, further studies are necessary to confirm this hypothesis and to assess the actual dose at which exposures to bisphenols are able to increase the sensitivity of the endometriotic cells to estradiol. Copyright © 2009 John Wiley & Sons, Ltd.     

Poly(1,4‐cyclohexylenedimethylene 1,4‐cyclohexanedicarboxylate): Influence of stereochemistry of 1,4‐cyclohexylene units on the thermal properties

A series of poly(1,4‐cyclohexylenedimethylene 1,4‐cyclohexanedicarboxylate) (PCCD) samples, characterized by different cis/trans ratio of the 1,4‐cyclohexanedicarbonyl unit, have been synthesized and analyzed by thermogravimetry (TGA), calorimetry (DSC), and X‐ray diffraction (WAXD). The thermal stability results are good and are not affected by the stereochemistry of the 1,4‐cyclohexylene units. On the other hand, the thermal transitions are notably influenced by the cis/trans content. With the increment of the trans content the polymer changes from completely amorphous to semicrystalline material. T_g, T_m, and crystallinity increase. These results suggest that the trans configuration induces a better chain packing and higher symmetry, improving the crystallizability of the samples. The effect of the molecular structure on the thermal properties is analyzed by using a statistical approach. From the effective correlations found between stereochemistry of the C₆ rings and transition temperatures it is possible to extrapolate that the configuration of 1,4‐cyclohexylene ring deriving from 1,4‐cyclohexanedicarboxylic acid or dimethyl 1,4‐cyclohexanedicarboxylate results to be the main element responsible for the thermal properties. This is due to the high rigidity of the 1,4‐cyclohexanedicarbonyl unit with respect to 1,4‐cyclohexanedimethyleneoxy unit, deriving from the diol. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 619–630, 2008     

Novel Poly(amidoamine)-Based Hydrogels as Scaffolds for Tissue Engineering

Summary: Poly(amidoamine)s are biocompatible biodegradable polymers, which can be easily functionalized with a number of bioactive and biomimetic compounds. Co-polymerization of these polymers with 4-aminobutyl guanidine (agmatine) leads to an RGD mimicking structure. Hydrogels based on this structure showed an enhanced cell adhesion and could be chemically linked to a glass substrate to create a bioadhesive support for cell growth. Preliminary optimization and cell adhesion tests on Madin-Darby Canine Kidney cells were performed, both on functionalized and non-functionalized structures, with promising results.     

Oxidative Stress in Mucopolysaccharidoses: Pharmacological Implications

Although mucopolysaccharidoses (MPS) are caused by mutations in genes coding for enzymes responsible for degradation of glycosaminoglycans, storage of these compounds is crucial but is not the only pathomechanism of these severe, inherited metabolic diseases. Among various factors and processes influencing the course of MPS, oxidative stress appears to be a major one. Oxidative imbalance, occurring in MPS and resulting in increased levels of reactive oxidative species, causes damage of various biomolecules, leading to worsening of symptoms, especially in the central nervous system (but not restricted to this system). A few therapeutic options are available for some types of MPS, including enzyme replacement therapy and hematopoietic stem cell transplantation, however, none of them are fully effective in reducing all symptoms. A possibility that molecules with antioxidative activities might be useful accompanying drugs, administered together with other therapies, is discussed in light of the potential efficacy of MPS treatment.     

The damping in MEMS inertial sensors both at high and low pressure levels

Except for MEMS working in a ultra high vacuum, the main cause of damping is the air surrounding the system. When the working pressure is equal to the atmospheric one (from now on called “high pressure,” i.e., 10⁵ Pa), the mean free path of an air molecule is much smaller than typical MEMS dimensions. Thus, air can be considered as a viscous fluid and two phenomena occur: flow damping and squeeze film damping. These two phenomena can be evaluated through a simplified Navier–Stokes equation. In a medium vacuum (from now on called “low pressure”), i.e., the “packaging” pressure, the air cannot be considered as a viscous fluid any more since the mean free path of an air molecule is of the same order of magnitude of typical MEMS dimensions. Thus, the molecular fluid theory must be used to estimate the damping. To predict the damping of a MEMS device both at high and low pressure levels, a multiphysics code was used. The proposed approach was validated through comparison with experimental data.     

Chirality and fragrance chemistry: stereoisomers of the commercial chiral odorants Muguesia and Pamplefleur

[structure: see text] The work describes the enzyme-mediated preparation and the odor evaluation of the single stereoisomers of the commercial odorants Muguesia and Pamplefleur. The synthetic approach to Muguesia stereoisomers helped to clear the assignment of the relative configuration of intermediate diols 5. The odor response of Pamplefleur isomers was found to be rather unusual. No stereoisomer prevailed, but each one played a definite role in establishing the odor sensation of the final blend.     

Two-point self-coordination of a dizinc(II) bispyridylporphyrin ruthenium complex leading selectively to a discrete molecular assembly: solution and solid-state characterization

The dizinc(II) bispyridylporphyrin ruthenium complex trans,cis,cis[RuCl2(CO)2(Zn.4'-cisDPyP)2] (1Zn, 4'-cisDPyP = 5,10-bis(4'-pyridyl)-15,20-diphenylporphyrin) features two donor (the uncoordinated 4'-N(py) atoms) and two acceptor (the Zn atoms) sites and is thus a building block suited for two-point coordination. 1H NMR spectroscopy indicates that 1Zn self-assembles in solution through Zn-4'-N(py) interactions to yield selectively a highly symmetrical discrete species, in which all donor and all acceptor sites of 1Zn are mutually saturated. Single-crystal X-ray analysis established that this adduct is a dimeric species, (1Zn)2, with a global S4 symmetry, in which the four porphyrins have a propeller-like arrangement. The dimeric species (1Zn)2 is a meso form derived from the combination of two 1Zn units with opposite helical chirality. The geometry of this highly symmetrical tetraporphyrin assembly in solution, as determined by NMR spectroscopy, is essentially the same as that found in the solid state. Thus 1Zn is an unprecedented example of metal-containing self-complementary building block that selectively recognizes itself through four Zn-N(py) interactions, and thus yields a very stable and symmetrical dimeric species, (1Zn)2, that features four porphyrins and six metal atoms (two Ru and four Zn).     

Strategies for proteomics with incompletely characterized genomes: the proteome of Bos taurus serum

A reference map for Bos taurus serum was obtained using proteomic tools: 21 proteins, plus several serum albumin fragments, have been identified in 47 spots. One of the major acute-phase reactants, haptoglobin, was also detected in a pathological serum. A number of technical problems had to be solved. (i) Spot resolution in two-dimensional electrophoresis (2-DE) is not easily optimized, as several proteins have similar molecular mass; different polyacrylamide concentration gradients were used for the analysis of various size ranges. (ii) Identification of proteins through mass spectrometry (MS) procedures is also difficult as the genome of Bos taurus is incompletely characterized. The program FASTS proved particularly useful, since it allows simultaneous searching of several unordered sequence fragments, which may be individually too short to provide a statistically valid match using BLAST.