Expression of Class I and II Major Histocompatibility Complex (MHC) Antigens in the Developing CNS

The clinical potential of neural transplantation depends upon the feasibility of allogenenic or xenogeneic transplants, particularly of fetal tissue. This, in turn, is influenced by donor cell expression of MHC antigens. MHC expression in the developing CNS in situ had not been defined. Here, a panel of antibodies was used to define MHC expression in the developing rat embryo

MicroRNA in prostate cancer: functional importance and potential as circulating biomarkers

BackgroundThis non-systematic review article aims to summarise the progress made in understanding the functional consequences of microRNA (miRNA) dysregulation in prostate cancer development, and the identification of potential miRNA targets as serum biomarkers for diagnosis or disease stratification.ResultsA number of miRNAs have been shown to influence key cellular processes involved in prostate tumourigenesis, including apoptosis-avoidance, cell proliferation and migration and the androgen signalling pathway. An overlapping group of miRNAs have shown differential expression in the serum of patients with prostate cancer of varying stages compared with unaffected individuals. The majority of studies thus far however, involve small numbers of patients and have shown variable and occasionally conflicting resultsConclusionMiRNAs show promise as potential circulating biomarkers in prostate cancer, but larger prospective studies are required to validate particular targets and better define their clinical utility

Observation of epitaxially ordered twinned zinc aluminate “nanoblades” on c-capphire

We report the observation of a novel nanostructured growth mode of the ceramic spinel zinc aluminate grown on c-sapphire in the form of epitaxially ordered twinned crystallites with pronounced vertically aligned “nanoblades” on top of these crystallites. The nanostructures are formed on bare c-sapphire substrates using a vapour phase transport method. Electron microscopy images reveal the nanostructure morphology and dimensions and allow direct and indirect observation of the twin boundary location in a number of samples. The nanoblade structure with sharply rising sidewalls gives rise to a distinctive bright contrast in secondary electron images in scanning electron microscopy measurements

Bioluminescence imaging of human embryonic stem cells transplanted in vivo in murine and chick models

Research into the behavior, efficacy, and biosafety of stem cells with a view to clinical transplantation requires the development of noninvasive methods for in vivo imaging of cells transplanted into animal models. This is particularly relevant for human embryonic stem cells (hESCs), because transplantation of undifferentiated hESCs leads to tumor formation. The present study aimed to monitor hESCs in real time when injected in vivo. hESCs were stably transfected to express luciferase, and luciferase expression was clearly detected in the undifferentiated and differentiated state. When transfected hESCs were injected into chick embryos, bioluminescence could be detected both ex and in ovo. In the SCID mouse model, undifferentiated hESCs were detectable after injection either into the muscle layer of the peritoneum or the kidney capsule. Tumors became detectable between days 10-30, with approximately a 3 log increase in the luminescence signal by day 75. The growth phase occurred earlier in the kidney capsule and then reached a plateau, whilst tumors in the peritoneal wall grew steadily throughout the period analysed. These results show the widespread utility of bioluminescent for in vivo imaging of hESCs in a variety of model systems for preclinical research into regenerative medicine and cancer biology. © Copyright 2009, Mary Ann Liebert, Inc

Exercise prevents obesity-induced cognitive decline and white matter damage in mice.

Obesity in the western world has reached epidemic proportions, and yet the long-term effects on brain health are not well understood. To address this, we performed transcriptional profiling of brain regions from a mouse model of western diet (WD)-induced obesity. Both the cortex and hippocampus from C57BL/6J (B6) mice fed either a WD or a control diet from 2 months of age to 12 months of age (equivalent to midlife in a human population) were profiled. Gene set enrichment analyses predicted that genes involved in myelin generation, inflammation, and cerebrovascular health were differentially expressed in brains from WD-fed compared to control diet-fed mice. White matter damage and cerebrovascular decline were evident in brains from WD-fed mice using immunofluorescence and electron microscopy. At the cellular level, the WD caused an increase in the numbers of oligodendrocytes and myeloid cells suggesting that a WD is perturbing myelin turnover. Encouragingly, cerebrovascular damage and white matter damage were prevented by exercising WD-fed mice despite mice still gaining a significant amount of weight. Collectively, these data show that chronic consumption of a WD in B6 mice causes obesity, neuroinflammation, and cerebrovascular and white matter damage, but these potentially damaging effects can be prevented by modifiable risk factors such as exercise

The Tulczyjew triple for classical fields

The geometrical structure known as the Tulczyjew triple has proved to be very useful in describing mechanical systems, even those with singular Lagrangians or subject to constraints. Starting from basic concepts of variational calculus, we construct the Tulczyjew triple for first-order Field Theory. The important feature of our approach is that we do not postulate {\it ad hoc} the ingredients of the theory, but obtain them as unavoidable consequences of the variational calculus. This picture of Field Theory is covariant and complete, containing not only the Lagrangian formalism and Euler-Lagrange equations but also the phase space, the phase dynamics and the Hamiltonian formalism. Since the configuration space turns out to be an affine bundle, we have to use affine geometry, in particular the notion of the affine duality. In our formulation, the two maps $\alpha$ and $\beta$ which constitute the Tulczyjew triple are morphisms of double structures of affine-vector bundles. We discuss also the Legendre transformation, i.e. the transition between the Lagrangian and the Hamiltonian formulation of the first-order field theor

The graded Jacobi algebras and (co)homology

Jacobi algebroids (i.e. `Jacobi versions' of Lie algebroids) are studied in the context of graded Jacobi brackets on graded commutative algebras. This unifies varios concepts of graded Lie structures in geometry and physics. A method of describing such structures by classical Lie algebroids via certain gauging (in the spirit of E.Witten's gauging of exterior derivative) is developed. One constructs a corresponding Cartan differential calculus (graded commutative one) in a natural manner. This, in turn, gives canonical generating operators for triangular Jacobi algebroids. One gets, in particular, the Lichnerowicz-Jacobi homology operators associated with classical Jacobi structures. Courant-Jacobi brackets are obtained in a similar way and use to define an abstract notion of a Courant-Jacobi algebroid and Dirac-Jacobi structure. All this offers a new flavour in understanding the Batalin-Vilkovisky formalism.Comment: 20 pages, a few typos corrected; final version to be published in J. Phys. A: Math. Ge

Hamiltonian dynamics and constrained variational calculus: continuous and discrete settings

The aim of this paper is to study the relationship between Hamiltonian dynamics and constrained variational calculus. We describe both using the notion of Lagrangian submanifolds of convenient symplectic manifolds and using the so-called Tulczyjew's triples. The results are also extended to the case of discrete dynamics and nonholonomic mechanics. Interesting applications to geometrical integration of Hamiltonian systems are obtained.Comment: 33 page