Expression of connexins in human preimplantation embryos in vitro

Intercellular communication via gap junctions is required to coordinate developmental processes in the mammalian embryo. We have investigated if the connexin (Cx) isoforms known to form gap junctions in rodent preimplantation embryos are also expressed in human embryos, with the aim of identifying species differences in communication patterns in early development. Using a combination of polyA PCR and immunocytochemistry we have assessed the expression of Cx26, Cx31, Cx32, Cx40, Cx43 and Cx45 which are thought to be important in early rodent embryos. The results demonstrate that Cx31 and Cx43 are the main connexin isoforms expressed in human preimplantation embryos and that these isoforms are co-expressed in the blastocyst. Cx45 protein is expressed in the blastocyst but the protein may be translated from a generally low level of transcripts: which could only be detected in the PN to 4-cell embryos. Interestingly, Cx40, which is expressed by the extravillous trophoblast in the early human placenta, was not found to be expressed in the blastocyst trophectoderm from which this tissue develops. All of the connexin isoforms in human preimplantation embryos are also found in rodents pointing to a common regulation of these connexins in development of rodent and human early embryos and perhaps other species

The Calculation of Molecular Quadrupole Moments in Some Fluorine Containing Compounds by the SCC Method

Sec (self-consistent charge) method was applied to a series of related fluorinated hydrocarbons. The calculated anisotropies of the second moments of the charge and the molecular quadrupoles are in fairly good agreement with experimental data. The results indicate that coulomb repulsion between electrons are absorbed· satisfactorily into the parameterization of the sec method

The placenta, maternal diet and adipose tissue development in the newborn

Background: A majority of adipose tissue present in the newborn possess the unique mitochondrial protein, uncoupling protein (UCP1). It is thus highly metabolically active and capable of producing 300 times more heat per unit mass than any other organ in the body. The extent to which maternal obesity and/or an obesogenic diet impacts on placental function thereby resetting the relative distribution of different types of fat in the fetus is unknown. Summary: Developmentally the majority (if not all) fat in the fetus can be considered as classical brown fat, in which UCP1 is highly abundant. In contrast, beige (or recruitable) fat which possess 90% less UCP1 may only appear after birth, as a majority of fat depots undergo a pronounced transformation that is usually accompanied by the loss of UCP1. The extent to which this process can be modulated in a depot-specific manner and/or changes in the maternal metabolic environment remain unknown. Key Messages: An increased understanding of the mechanism by which offspring born to mothers possess excessive adipose tissue could enable sustainable interventions designed to promote the abundance of UCP1 possessing adipocytes. Ultimately, this would increase their energy expenditure and improve glucose homeostasis in these individuals

A numerical study of a binary Yukawa model in regimes characteristic of globular proteins in solutions

The main goal of this paper is to assess the limits of validity, in the regime of low concentration and strong Coulomb coupling (high molecular charges), for a simple perturbative approximation to the radial distribution functions (RDF), based upon a low-density expansion of the potential of mean force and proposed to describe protein-protein interactions in a recent Small-Angle-Scattering (SAS) experimental study. A highly simplified Yukawa (screened Coulomb) model of monomers and dimers of a charged globular protein ($\beta$-lactoglobulin) in solution is considered. We test the accuracy of the RDF approximation, as a necessary complementary part of the previous experimental investigation, by comparison with the fluid structure predicted by approximate integral equations and exact Monte Carlo (MC) simulations. In the MC calculations, an Ewald construction for Yukawa potentials has been used to take into account the long-range part of the interactions in the weakly screened cases. Our results confirm that the perturbative first-order approximation is valid for this system even at strong Coulomb coupling, provided that the screening is not too weak (i.e., for Debye length smaller than monomer radius). A comparison of the MC results with integral equation calculations shows that both the hypernetted-chain (HNC) and the Percus-Yevick (PY) closures have a satisfactory behavior under these regimes, with the HNC being superior throughout. The relevance of our findings for interpreting SAS results is also discussed.Comment: Physical Review E, in press (2005

An Overlapping Spheres Multiple Scattering Xa Study of the Perfluoro Effect on the Ionisation Potentials and Electron Transmission Spectra of Fluorosubstituted Benzenes

The overlapping spheres multiple scattering Xu. method is used to investigate the nature of the »perfluoro effect« through · ca\u271culations on the ionisation potentials (IPs), electron affinities (EAs), and elastic cross sections for electron scattering of benzene, para-difluorobenzene, 1,3,5-trifluorobenzene, 1,2,4,5-tetrafluorobenzene and hexafluorobenzene (HXFB). The results of the IP calculations agree with experiment and, for the most part, with HAM/3 calculations but they differ considerably from assignments made with the aid of Hartree-Fock minimal basis set calculations. The calculated derivative curves for electron-molecule scattering agree with the experimentally determined ones, but the detailed interpretation of the elastic cross sections differs considerably from those given previously. In previous work, all the resonances have been interpreted in terms of the unoccupied valence orbitals but in this work the second strong resonance, seen in all the fluorinated benzenes except HXFB, is assigned to a temporary negative ion state formed by electron capture in a dn type diffuse Rydberg orbital. In HXFB there is only one strong resonance and this also is assigned to electron capture in a dn type orbital. HXFB is the only one of the series for which an experimental value for the bound EA is known (1.8 eV). The theoretical value (1.7 eV) is in good aggrement

Reduction of Experimental Myocardial Infarct Size by Corticosteroid Administration

The influence of the administration of pharmacologic doses of hydrocortisone on the extent and severity of acute myocardial ischemic injury and on subsequent necrosis after acute coronary occlusion was investigated in 28 dogs. In order to study acute myocardial injury, repeated epicardial electrocardiograms were recorded from 10 to 15 sites on the anterior surface of the left ventricle. Average ST segment elevation (ST) and the number of sites in which ST segment elevation exceeded 2 mV (NST), indices of the magnitude and extent of myocardial injury, respectively, were analyzed at 30 and 60 min after coronary occlusion. In the control group ST and NST did not change significantly in this time interval while in the treated group, which received 50 mg/kg hydrocortisone just after the 30 min recording, ST fell from 3.5+/-0.8 to 1.1+/-0.4 mV (P 2 mV) in the control group showed histologic changes compatible with early myocardial infarction in 96% of specimens, while this occurred only in 61% and 63% of specimens, respectively, in the treated groups, showing that over one third of the sites were protected from undergoing necrosis due to the intervening hydrocortisone treatment. Thus pharmacological doses of hydrocortisone prevent myocardial cells from progressing to ischemic necrosis even when administration is initiated 6 h after coronary occlusion

Coronary Artery Reperfusion

The effects of coronary artery reperfusion 3 hr after coronary occlusion on contractile function and the development of myocardial damage at 24 hr was studied experimentally. In 14 control and 6 reperfused dogs, relationships between epicardial ST segment elevation 15 min after coronary occlusion and myocardial creatine phosphokinase activity (CPK) and histologic appearance 24 hr later were examined. The electrocardiograms were recorded from 10 to 15 sites on the left ventricular epicardium and transmural samples for CPK and histology were obtained from the same sites where epicardial electrocardiograms had been recorded. An inverse relation existed between ST segment elevation (mv) 15 min after occlusion and log CPK activity (IU/ mg of protein) 24 hr later, log CPK = - 0.06ST + 1.26. In dogs subjected to coronary artery reperfusion, there was significantly less CPK depression (log CPK = - 0.01ST + 1.31, [P < 0.01]) than that expected from the control group. In the control group 97% of specimens showing ST segment elevations over 2 mv at 15 min showed abnormal histology 24 hr later. In contrast, in the reperfused group 43% of sites exhibiting elevated ST segment at 15 min showed abnormal histology 24 hr later. In six additional dogs it was shown that the paradoxical movement of the left ventricular wall could be reversed within 1 hr of perfusion. Therefore, by enzymatic and histologic criteria, as well as by functional assessment, coronary artery reperfusion 3 hr after occlusion resulted in salvage of myocardial tissue