Efficient delivery of Cre-recombinase to neurons in vivo and stable transduction of neurons using adeno-associated and lentiviral vectors

Background

As development proceeds the human embryo attains an ever more complex three dimensional (3D) structure. Analyzing the gene expression patterns that underlie these changes and interpreting their significance depends on identifying the anatomical structures to which they map and following these patterns in developing 3D structures over time. The difficulty of this task greatly increases as more gene expression patterns are added, particularly in organs with complex 3D structures such as the brain. Optical Projection Tomography (OPT) is a new technology which has been developed for rapidly generating digital 3D models of intact specimens. We have assessed the resolution of unstained neuronal structures within a Carnegie Stage (CS)17 OPT model and tested its use as a framework onto which anatomical structures can be defined and gene expression data mapped.

Results

Resolution of the OPT models was assessed by comparison of digital sections with physical sections stained, either with haematoxylin and eosin (H&E) or by immunocytochemistry for GAP43 or PAX6, to identify specific anatomical features. Despite the 3D models being of unstained tissue, peripheral nervous system structures from the trigeminal ganglion (~300 μm by ~150 μm) to the rootlets of cranial nerve XII (~20 μm in diameter) were clearly identifiable, as were structures in the developing neural tube such as the zona limitans intrathalamica (core is ~30 μm thick). Fourteen anatomical domains have been identified and visualised within the CS17 model. Two 3D gene expression domains, known to be defined by Pax6 expression in the mouse, were clearly visible when PAX6 data from 2D sections were mapped to the CS17 model. The feasibility of applying the OPT technology to all stages from CS12 to CS23, which encompasses the major period of organogenesis for the human developing central nervous system, was successfully demonstrated.

Conclusion

In the CS17 model considerable detail is visible within the developing nervous system at a minimum resolution of ~20 μm and 3D anatomical and gene expression domains can be defined and visualised successfully. The OPT models and accompanying technologies for manipulating them provide a powerful approach to visualising and analysing gene expression and morphology during early human brain development.     

Low-temperature heat capacity and ac magnetic susceptivility of the re-entrant ferromagnetic superconductor Ho1.2Mo6S8

Thermal hysteresis in the ac magnetic susceptibility and a spike-shaped anomaly in the heat capacity, superimposed on a feature due to ferromagnetic ordering, have been observed at the coupled superconducting to normal-ferromagnetic transition in Ho_1.2Mo₆S₈.     

Superconductivity and crystal structure of ternary CuxMo3S4 compounds with 0 ≤ x ≤ 1 prepared by anodic oxidation of Cu1.0Mo3S4

Superconductivity and crystal structure data are reported for a series of ternary Cu_xMo₃S₄ samples with 0 ≤ x ≤ 1 which were prepared by anodic oxidation of Cu_1.0Mo₃S₄. A phase with the composition Cu_0.5Mo₃S₄ was found to have rhombohedral lattice parameters $\text{a}{}_{\mathrm{R}}\text{= 6.447(5)}\text{A}\text{?}$ and α_R = 93.74(4) ° and a superconducting critical temperature T_c = 5.8 K. The dependence of T_c on pressure for Cu_0.5Mo₃S₄ has been measured between 0 and 19 kbar.     

Low temperature heat capacity of rare earth molybdenum sulfides

Pronounced anomalies in the heat capacity of Gd_1.2Mo₆S₈, and probably Dy_1.2Mo₆S₈ are associated with the previously reported antiferromagnetic transition which occurs in the superconducting state in each of these compounds.     

Positive integer solutions of the diophantine equation x 2 − L n xy + (−1) n y 2 = ±5 r

In this paper, we consider the equation x ²?L _n x y+(?1) ⁿ y ² = ±5 ^r and determine the values of n for which the equation has positive integer solutions x and y. Moreover, we give all positive integer solutions of the equation x ²?L _n x y+(?1) ⁿ y ² = ±5 ^r when the equation has positive integer solutions.     

Magnetic and piezoelectric properties of the Bi1 − x La x FeO3 system near the transition from the polar to antipolar phase

The crystal structure, piezoelectric and magnetic properties of the Bi_{1 ? x} La _x FeO₃ solid-solution system near the structural transition between the rhombohedral and orthorhombic phases (0.15 ≤ x ≤ 0.2) have been investigated. The regions of existence of the polar rhombohedral and orthorhombic phases have been determined, and the sequence of structural transitions as a function of the lanthanum ion concentration and temperature has been studied. The maximum piezoelectric signal is found for the solid solution with the composition x = 0.16, which has a single-phase rhombohedral structure. The relation between the type of crystal structure distortions and the increase in the magnetization upon the concentration-driven structural transition from the polar to antipolar phase has been established.     

A fully anisotropic hierarchical hybrid cellular automaton algorithm to simulate bone remodeling

Computational models of the bone remodeling process have been utilized to further our understanding of the adaptation of bone architecture to changes in its mechanical environment. The hierarchical hybrid cellular automata (HHCA) algorithm is a multi-scale approach for the simulation of the adaptation of bone. Currently, this remodeling algorithm utilizes the apparent material properties of the trabecular architecture. The objective of this work is to increase the fidelity of the HHCA algorithm by incorporating the local anisotropic properties of these structures. Preliminary analyses display improved efficiency and a more consistent material distribution when incorporating anisotropic properties into the HHCA methodology.     

Fluoride content by ion chromatography using a suppressed conductivity detector and osmolality of bitterns discharged into the Pacific Ocean from a saltworks: feasible causal agents in the mortality of green turtles (Chelonia mydas) in the Ojo de Liebre lagoon, Baja California Sur, Mexico.

On December 1997, 94 corpses of green turtles, Chelonia mydas, were found at the Ojo de Liebre lagoon (OLL) adjacent to the industrial operation of Exportadora de Sal S. A (ESSA), the largest saltworks in the world, owned by the Mexican Government and Mitsubishi Corporation, located in Baja California Sur, Mexico. Every year about 551 x 10(6) m3 of seawater is solar evaporated, producing 7 x 10(6) tons of salt and 24.6 x 10(6) m3 of bitterns, the latter being discharged into the OLL, which is a costal lagoon of the Pacific Ocean. ESSA claimed that bitterns contain the same salts present in seawater, but 20-fold more concentrated than the former. Ion chromatography with a conductivity detector and ion suppression was used to determine the F-, Cl-, SO4(2-) and CO3(2-) contents of seawater, brines and bitterns collected at ESSA. Furthermore, the osmolality of brines and bitterns from ESSA was measured. F- content in bitterns was 60.5-fold more than that in seawater. The bitterns osmolality was 11,000 mosm/kg of water, whereas the turtle's plasma osmolality was about 400 mosm/kg of water. We concluded that the dumping of bitterns into the ocean should be avoided.     

Charge ordering in the electron doped Ca1−xYxMnO3 manganites

Structural studies on the electron doped Ca_1−xY_xMnO₃ are presented. At 300 K, orthorhombic O-phase was observed in all cases, associated to low electric resistivity and high Curie–Weiss temperature. For samples with x>0.07, structural phase transitions to more distorted orthorhombic and monoclinic phases were found at T<170K. In these phases only weak ferromagnetic interactions were observed.