Immunohistochemical, ultrastructural and functional analysis of axonal regeneration through peripheral nerve grafts containing Schwann cells expressing BDNF, CNTF or NT3

Objective  To establish reference values for activated coagulation time (ACT) in normal cats and dogs, by visual assessment of clot formation using the MAX-ACTTM tube. Subjects  We recruited 43 cats and 50 dogs for the study; 11 cats and 4 dogs were excluded from the statistical analysis because of abnormalities on clinical examination or laboratory testing including anaemia, prolonged prothrombin time (PT) or activated partial thromboplastin time (APTT), or insufficient plasma volume for comprehensive laboratory coagulation testing. Procedure  Blood samples were collected via direct venipuncture for MAX-ACT, packed cell volume/total solids, manual platelet estimation and PT/APTT measurement. Blood (0.5 mL) was mixed gently in the MAX-ACT tube at 37°C for 30 s, then assessed for clot formation every 5 to 10 s by tipping the tube gently on its side and monitoring for magnet movement. The endpoint was defined as the magnet lodging in the clot. The technique was tested with 10 dogs by collecting two blood samples from the same needle insertion and running a MAX-ACT on each simultaneously. Results  In normal cats the mean MAX-ACT was 66 s (range 55–85 s). In normal dogs the mean was 71 s (range 55–80 s). There was no statistical difference between the first and second samples collected from the same needle insertion. Conclusions and Clinical Relevance  In both cats and dogs, a MAX-ACT result >85 s should be considered abnormal and further coagulation testing should be performed. Additionally, failure to discard the first few drops of the sample does not appear to significantly affect results

In vitro evaluation of sustained released matrix tablets containing ibuprofen: a model poorly water-soluble drug

ABSTRACT A matrix system was developed that releases ibuprofen (IB) over a 12-hour period and the influence of the polymer type and concentration on the release rate of the drug was evaluated. Tablets containing different concentrations of Carbopol (CP), hydroxypropyl methylcellulose (HPMC), or ethyl cellulose (EC) were prepared using direct compression and the drug content, content uniformity, hardness, friability, dissolution performance, and in vitro release kinetics were examined. Formulated tablets were found to be within acceptable limits for physical and chemical parameters. The release kinetics of the Carbopol(r)971P 8% formulation showed the best linearity (r 2 =0.977) in fitting zero-order kinetics, suggesting the release rate was time independent. The drug release from tablets containing 8% CP was extended over approximately 18 hours and the release kinetics were nearly linear, suggesting that this system has the potential to maintain constant plasma drug concentrations over 12 hours, which could reduce the frequency of administration and the occurrence of adverse effects associated with repeated administration of conventional IB tablets

Cross-coupling of amide and amide derivatives to umbelliferone nonaflates: synthesis of coumarin derivatives and fluorescent materials

The Buchwald-Hartwig cross-coupling reaction between 4-methylumbelliferone derived nonaflates and amides, carbamates and sulfonamides is described. A wide variety of N-substituted 7-amino coumarin analogues were prepared in good to excellent yields. The photophysical properties of aqueous soluble derivatives were determined and displayed auxochrome based variations. Gram scale synthesis provided an acrylamide analogue which was used to fabricate a fluorescent poly(2-hydroxylethyl methacrylate) (pHEMA) hydrogel that was resistant to leaching in ultrapure H2O. We envisage our reported protocol to access 4-methylumbelliferone derivatives will find use towards the development of new fluorescent coumarin-based probes by researchers in the field.Shane M. Hickey, Samuel O. Nitschke, Martin J. Sweetman, Christopher J. Sumby, Douglas A. Brooks, Sally E. Plush and Trent D. Ashto

Silicon diatom frustules as nanostructured photoelectrodes

In the quest for solutions to meeting future energy demands, solar fuels play an important role. A particularly promising example is photocatalysis since even incremental improvements in performance in this process are bound to translate into significant cost benefits. Here, we report that semiconducting and high surface area 3D silicon replicas prepared from abundantly available diatom fossils sustain photocurrents and enable solar energy conversion.Soundarrajan Chandrasekaran, Martin J. Sweetman, Krishna Kant, William Skinner, Dusan Losic, Thomas Nann and Nicolas H. Voelcke

A 3,4-dimethoxy-1,8-naphthalimide for lipid droplet imaging in live and fixed cells

Lipid droplets (LDs) are found in most eukaryotic cells and in addition to serving as lipid reservoirs, these highly dynamic organelles play fundamental roles in cell metabolism and growth. The study of LDs and their in- teractions with other cellular compartments provides new insights into normal cell biology and disease processes such as virus packaging, metabolic disorders, and cancer progression. Here we report the synthesis and comprehensive evaluation of two readily prepared, low molecular weight 3,4-dimethoxy-1,8-naphthalimides, as selective LD stains. The newly synthesised 1,8-naphthalimide derivative (DMN-LD), demonstrated impressive versatility compared to currently available options, by staining LDs in both live and fixed cells, as well as a three- dimensional spheroid, using both single and two-photon excitation. This new imaging agent has the potential to further unravel the complex biology of LDs, which are essential to cell survival, and when altered, underpin many disease states.Ian R.D. Johnson, Elley E. Rudebeck, Martin J. Sweetman, Alexandra Sorvina, Trent D. Ashton, Frederick M. Pfeffer, Douglas A. Brooks, Shane M. Hicke

Analysis of two P-element enhancer-trap insertion lines that show expression in the giant fibre neuron of Drosophila melanogaster

The giant fibre system (GFS) of Drosophila is a simple neural circuit that mediates escape responses in adult flies. Here we report the initial characterization of two genes that are preferentially expressed in the GFS. Two P-element insertion lines, carrying the GAL4 transcriptional activator, were identified that exhibited pronounced expression in elements of the GFS and relatively low levels elsewhere within the adult central nervous system. Genomic DNA flanking the P-element insertion site was recovered from each of these lines, sequenced, and nearby transcripts identified and confirmed to exhibit GFS expression by in situ hybridization. This analysis revealed that these P-elements were in previously characterized genes. Line P[GAL4]-A307 has an insert in the gene short stop for which we have identified a novel transcript, while line P[GAL4]-141 has an insert in the transcription factor ken and barbie. Here we show that ken and barbie mutants have defects in escape behaviour, behavioural responses to visual stimuli and synaptic functions in the GFS. We have therefore revealed a neural role for a transcription factor that previously had no implicated neural function