Growth Factor Stimulation Improves the Structure and Properties of Scaffold-Free Engineered Auricular Cartilage Constructs

The reconstruction of the external ear to correct congenital deformities or repair following trauma remains a significant challenge in reconstructive surgery. Previously, we have developed a novel approach to create scaffold-free, tissue engineering elastic cartilage constructs directly from a small population of donor cells. Although the developed constructs appeared to adopt the structural appearance of native auricular cartilage, the constructs displayed limited expression and poor localization of elastin. In the present study, the effect of growth factor supplementation (insulin, IGF-1, or TGF-β1) was investigated to stimulate elastogenesis as well as to improve overall tissue formation. Using rabbit auricular chondrocytes, bioreactor-cultivated constructs supplemented with either insulin or IGF-1 displayed increased deposition of cartilaginous ECM, improved mechanical properties, and thicknesses comparable to native auricular cartilage after 4 weeks of growth. Similarly, growth factor supplementation resulted in increased expression and improved localization of elastin, primarily restricted within the cartilaginous region of the tissue construct. Additional studies were conducted to determine whether scaffold-free engineered auricular cartilage constructs could be developed in the 3D shape of the external ear. Isolated auricular chondrocytes were grown in rapid-prototyped tissue culture molds with additional insulin or IGF-1 supplementation during bioreactor cultivation. Using this approach, the developed tissue constructs were flexible and had a 3D shape in very good agreement to the culture mold (average error <400 µm). While scaffold-free, engineered auricular cartilage constructs can be created with both the appropriate tissue structure and 3D shape of the external ear, future studies will be aimed assessing potential changes in construct shape and properties after subcutaneous implantation.     

XY sex-reversal syndrome in the domestic horse

The XY sex-reversal syndrome occurs when a phenotypic mare is born that has the karyotype of a stallion. The syndrome is manifested by both genotypic and phenotypic heterogeneity. The sex-reversed genetic condition occurs frequently within certain pedigrees where XY females have been found and can be readily detected by chromosome karyotyping. The phenotypic spectrum ranges from the feminine mare with a reproductive tract that is within normal limits to the greatly masculinized mare. Pedigree analysis suggests that there are two modes of inheritance: (1) an X-linked recessive or autosomal sex-limited dominant transmitted through the female and (2) an autosomal sex-limited dominant or a Y chromosomal mutation with variable expression transmitted through the male. The proportion of female to male progeny of the 69 top-producing Arabian stallions in the world is 53 to 47, indicating that the occurrence of genetic defects affecting the sex ratio such as the XY sex-reversal syndrome is relatively infrequent. In nine cases where the sex ratios of stallions deviated significantly from the expected sex ratio, the incidence of female infertility also increased. Cytogenetic screening of young animals would provide for early detection and avoid the expense and disappointment of continuous breeding attempts. Just as importantly, it would aid in the reduction and the possible elimination of this genetic condition from breeding herds.     

A recombination event excludes the ROM1 locus from the Best's vitelliform macular dystrophy region

Best's vitelliform macular degeneration has been genetically linked to chromosome 11. Subsequently, the disease locus has been refined to an interval between D11S903 and PYGM and, more recently, between D11S986 and D11S480. The gene encoding ROM1, a photoreceptor-specific membrane protein, has been independently mapped within the Best's disease region and has thus become a strong candidate for the Best's disease gene. In this study, we have mapped ROM1 relative to Best's disease and the loci D11S986, UGB (uteroglobin), and PYGM (human muscle glycogen phosphorylase) in recombinant Best's disease chromosomes. We demonstrate that UGB is localized proximal to ROM1 and that both UGB and ROM1 recombine with the disease phenotype. Thus, this analysis excluded ROM1 as the Best's disease gene.     

Gender Stereotype Susceptibility

Gender affects performance on a variety of cognitive tasks, and this impact may stem from socio-cultural factors such as gender stereotyping. Here we systematically manipulated gender stereotype messages on a social cognition task on which no initial gender gap has been documented. The outcome reveals: (i) Stereotyping affects both females and males, with a more pronounced impact on females. Yet an explicit negative message for males elicits a striking paradoxical deterioration in performance of females. (ii) Irrespective of gender and directness of message, valence of stereotype message affects performance: negative messages have stronger influence than positive ones. (iii) Directness of stereotype message differentially impacts performance of females and males: females tend to be stronger affected by implicit than explicit negative messages, whereas in males this relationship is opposite. The data are discussed in the light of neural networks underlying gender stereotyping. The findings provide novel insights into the sources of gender related fluctuations in cognition and behavior.     

The distribution of actin in non-muscle cells : The use of actin antibody in the localization of actin within the microfilament bundles of mouse 3T3 cells

Living mouse 3T3 cells display a complex array of fibrous structures which are visible with phase contrast, Nomarski and polarized light optics. When cells are fixed and stained for indirect immunofluorescence with actin antibody, the same fibers show intense fluorescence indicating that they contain actin. Electron microscopy reveals that these fibrous structures consist of submembranous bundles of microfilaments located primarily on the attached side of the cells. The results are discussed in terms of the intracellular localization of a possible submembranous contractile system involved in motile activities such as cell locomotion.     

Molecular Features Related to HIV Integrase Inhibition Obtained from Structure- and Ligand-Based Approaches

Among several biological targets to treat AIDS, HIV integrase is a promising enzyme that can be employed to develop new anti-HIV agents. The aim of this work is to propose a mechanistic interpretation of HIV-1 integrase inhibition and to rationalize the molecular features related to the binding affinity of studied ligands. A set of 79 HIV-1 integrase inhibitors and its relationship with biological activity are investigated employing 2D and 3D QSAR models, docking analysis and DFT studies. Analyses of docking poses and frontier molecular orbitals revealed important features on the main ligand-receptor interactions. 2D and 3D models presenting good internal consistency, predictive power and stability were obtained in all cases. Significant correlation coefficients (r² = 0.908 and q² = 0.643 for 2D model; r² = 0.904 and q² = 0.719 for 3D model) were obtained, indicating the potential of these models for untested compounds. The generated holograms and contribution maps revealed important molecular requirements to HIV-1 IN inhibition and several evidences for molecular modifications. The final models along with information resulting from molecular orbitals, 2D contribution and 3D contour maps should be useful in the design of new inhibitors with increased potency and selectivity within the chemical diversity of the data.