Demonstration of a compact double-reflection transmissive beam scanner operating at 1550 nm wavelength.

A compact forward-directed transmissive beam scanner operating at a wavelength of 1550 nm was constructed and characterized. The scanner consists of two wire-grid polarizers (WGPs) surrounding a 45° Faraday rotator, causing incident light to reflect once from each WGP before transmitting through the second polarizer. Scanning is achieved by tilting one of the WGPs. Measured efficiency remained above 73% over a 90° forward scan range (-45∘ to +45∘) for vertically polarized incident light. Additionally, we measured the efficiency versus beam deflection for four different incident linear polarization configurations, three of which maintained >70% efficiency for deflection angles up to -60∘.

Transthyretin Glu54Leu - an unknown mutation within the Swedish population associated with amyloid cardiomyopathy and a unique fibril type.

For the first time, we report of a Swedish family of five individuals with a TTR Glu54Leu (p. Glu74Leu) mutation in the transthyretin gene. This mutation has been previously described a few times in the literature, but no phenotypic or clinical description has been done before. The most common mutation in the Swedish population is TTRVal30Met and is mostly found in the Northern part of Sweden. Interestingly, the TTRGlu54Leu mutation was found in the same endemic area. The main phenotype of the TTR Glu54Leu patients is severe cardiomyopathy, which resulted in heart transplantation for the index person. As previously seen for ATTR amyloidosis patients with mainly cardiomyopathy, the amyloid fibrils consisted of a mixture of full-length and fragmented TTR species. However, western blot analyses detected a previously unrecognized band, indicating that these patients may have a third, so far unrecognized, fibril composition type that is distinct from the usual type A band pattern.

NOVEL RADIOGRAPHIC TECHNIQUE FOR PREGNANCY DETECTION IN THE MANED WOLF (CHRYSOCYON BRACHYURUS) WITHOUT ANESTHESIA.

Maned wolves ( Chrysocyon brachyurus ) maintained in ex situ populations challenge veterinarians and managers with high neonatal mortality and parental incompetence. These challenges led to the development of a novel diagnostic approach for pregnancy detection using radiographic imaging without anesthesia or sedation. To do this, a specialized crate was constructed to easily contain a single maned wolf, allowing the capture of lateral projection radiographic images of the abdomen prior to and throughout a 66-day pregnancy (days 20, 34, 48, and 55 of 66). Radiographs taken at days 48 and 55 postbreeding showed evidence of neonatal skeleton mineralization, confirming pregnancy with two pups. The dam gave birth at day 66 to two pups. This technical report describes a novel approach without anesthesia for successful radiographic pregnancy detection and determination of litter size in the maned wolf, a midsize carnivore, using a specially constructed crate.

Undifferentiated murine embryonic stem cells used to model the effects of the blue-green algal toxin cylindrospermopsin on preimplantation embryonic cell proliferation.

Undifferentiated mouse embryonic stem cell (mES) proliferation in vitro resembles aspects of in vivo pre-implantation embryonic development. mES were used to assess the embryo-toxicity of cylindrospermopsin (CYN), a water contaminant with an Australian Drinking Water Guideline (ADWG) of 1 µg/L. mES exposed to 0-1 µg/mL CYN for 24-168 h were subjected to an optimised crystal violet viability assay. mES exposed to retinoic acid ± 1 µg/L CYN differentiated into neural-like cells confirmed by morphological examination and RT-PCR for Oct4, Brachyury and Nestin. The CYN No Observed Effect Concentration (OEC) was 0.5 µg/mL, the Lowest OEC was 1 µg/mL (p < 0.001, n = 3), and the IC50 was 0.86 µg/mL after 24 h. The ADWG 1 µg/L CYN did not affect differentiation or proliferation after 72 h, but decreased proliferation after 168 h (p < 0.05). We conclude that higher algal bloom-associated CYN concentrations have the potential to impair in vivo pre-implantation development, and the mES crystal violet assay has broad application to screening environmental toxins.

Differentiation of embryonic stem cells to a neural fate: a route to re-building the nervous system?

The many and varied proposed applications of cell replacement therapies in the treatment of human disease states, particularly those arising from cell loss or dysfunction, have been discussed widely in both the scientific and popular press. Although an attractive concept, cell therapies require the development of a readily available source of donor cells suitable for transplantation. Embryonic stem (ES) cells, with proven ability to differentiate to all cell populations of the embryo and adult in vitro, provide a potential source of therapeutic cells. The differentiation capability of mouse ES cells in vitro has been studied extensively over the last 20 years and the formation of neural precursors and neural cell lineages from mouse ES cells is well established. Cell populations highly enriched/homogenous in neural precursors have been achieved using a variety of chemical or biological inducing agents coupled with selective growth conditions. Preliminary reports suggest that similar neural enrichment is seen when these methodologies are applied to primate and human ES cells. ES cell-derived neural precursors have been analyzed in vitro and in vivo and found to be functionally normal and, after introduction into rodent models of human neurodegenerative diseases, capable of effecting measurable disease recovery. We review progress in the formation of neural precursors from mouse ES cells, particularly the recent reports of directed differentiation of ES in response to biological inductive factors, and assess the transfer of these approaches to human ES cells.

Hypoxia-inducible factor-1alpha mRNA contains an internal ribosome entry site that allows efficient translation during normoxia and hypoxia.

HIF-1alpha is the regulated subunit of the HIF-1 transcription factor, which induces transcription of a number of genes involved in the cellular response to hypoxia. The HIF-1alpha protein is rapidly degraded in cells supplied with adequate oxygen but is stabilized in hypoxic cells. Using polysome profile analysis, we found that translation of HIF-1alpha mRNA in NIH3T3 cells is spared the general reduction in translation rate that occurs during hypoxia. To assess whether the 5'UTR of the HIF-1alpha mRNA contains an internal ribosome entry site (IRES), we constructed a dicistronic reporter with the HIF-1alpha 5'UTR inserted between two reporter coding regions. We found that the HIF-1alpha 5'UTR promoted translation of the downstream reporter, indicating the presence of an IRES. The IRES had activity comparable to that of the well-characterized c-myc IRES. IRES activity was not affected by hypoxic conditions that caused a reduction in cap-dependent translation, and IRES activity was less affected by serum-starvation than was cap-dependent translation. These data indicate that the presence of an IRES in the HIF-1alpha 5'UTR allows translation to be maintained under conditions that are inhibitory to cap-dependent translation.