A genetically encoded reporter of synaptic activity in vivo

To image synaptic activity within neural circuits, we tethered the genetically encoded calcium indicator (GECI) GCaMP2 to synaptic vesicles by fusion to synaptophysin. The resulting reporter, SyGCaMP2, detected the electrical activity of neurons with two advantages over existing cytoplasmic GECIs: it identified the locations of synapses and had a linear response over a wider range of spike frequencies. Simulations and experimental measurements indicated that linearity arises because SyGCaMP2 samples the brief calcium transient passing through the presynaptic compartment close to voltage-sensitive calcium channels rather than changes in bulk calcium concentration. In vivo imaging in zebrafish demonstrated that SyGCaMP2 can assess electrical activity in conventional synapses of spiking neurons in the optic tectum and graded voltage signals transmitted by ribbon synapses of retinal bipolar cells. Localizing a GECI to synaptic terminals provides a strategy for monitoring activity across large groups of neurons at the level of individual synapses

Tcf7l2 is required for left-right asymmetric differentiation of habenular neurons.

BACKGROUND: Although left-right asymmetries are common features of nervous systems, their developmental bases are largely unknown. In the zebrafish epithalamus, dorsal habenular neurons adopt medial (dHbm) and lateral (dHbl) subnuclear character at very different frequencies on the left and right sides. The left-sided parapineal promotes the elaboration of dHbl character in the left habenula, albeit by an unknown mechanism. Likewise, the genetic pathways acting within habenular neurons to control their asymmetric differentiated character are unknown. RESULTS: In a forward genetic screen for mutations that result in loss of habenular asymmetry, we identified two mutant alleles of tcf7l2, a gene that encodes a transcriptional regulator of Wnt signaling. In tcf7l2 mutants, most neurons on both sides differentiate with dHbl identity. Consequently, the habenulae develop symmetrically, with both sides adopting a pronounced leftward character. Tcf7l2 acts cell automously in nascent equipotential neurons, and on the right side, it promotes dHbm and suppresses dHbl differentiation. On the left, the parapineal prevents this Tcf7l2-dependent process, thereby promoting dHbl differentiation. CONCLUSIONS: Tcf7l2 is essential for lateralized fate selection by habenular neurons that can differentiate along two alternative pathways, thereby leading to major neural circuit asymmetries

A Synaptic Mechanism for Temporal Filtering of Visual Signals

The visual system transmits information about fast and slow changes in light intensity through separate neural pathways. We used in vivo imaging to investigate how bipolar cells transmit these signals to the inner retina. We found that the volume of the synaptic terminal is an intrinsic property that contributes to different temporal filters. Individual cells transmit through multiple terminals varying in size, but smaller terminals generate faster and larger calcium transients to trigger vesicle release with higher initial gain, followed by more profound adaptation. Smaller terminals transmitted higher stimulus frequencies more effectively. Modeling global calcium dynamics triggering vesicle release indicated that variations in the volume of presynaptic compartments contribute directly to all these differences in response dynamics. These results indicate how one neuron can transmit different temporal components in the visual signal through synaptic terminals of varying geometries with different adaptational properties

Guideline for the treatment of myelodysplastic syndromes (MDS) in South Africa

The original publication is available at http://www.samj.org.zaIntroduction. Myelodysplastic syndromes (MDS) encompass a heterogeneous group of clonal haematopoietic disorders characterised by chronic and progressive cytopenias resulting from ineffective haematopoiesis. Treatment is complicated by differences in disease mechanisms in different subgroups, variable clinical phenotypes and risk of progression to acute myeloid leukaemia. Rationale. Changes in disease classification, prognostic scoring systems, the availability of novel treatment options and the absence of South African guidelines for the diagnosis and management of these complex disorders underpinned the need for the development of these recommendations. Methods. These recommendations are based on the opinion of a number of experts in the field from the laboratory as well as clinical settings and came from both the private and institutional academic environments. The most recent literature as well as available guidelines from other countries were discussed and debated at a number of different meetings held over a 2-year period. Results. A comprehensive set of recommendations was developed focusing on risk stratification, supportive management and specific treatment. Novel agents and their indications are discussed and recommendations are made based on best available evidence and taking into account the availability of treatments in South Africa. Conclusion. Correct diagnosis, risk stratification and appropriate therapeutic choices are the cornerstones of success in the management of patients with MDS.Publishers' Versio

EGCG Enhances the Therapeutic Potential of Gemcitabine and CP690550 by Inhibiting STAT3 Signaling Pathway in Human Pancreatic Cancer

Background: Signal Transducer and Activator of Transcription 3 (STAT3) is an oncogene, which promotes cell survival, proliferation, motility and progression in cancer cells. Targeting STAT3 signaling may lead to the development of novel therapeutic approaches for human cancers. Here, we examined the effects of epigallocathechin gallate (EGCG) on STAT3 signaling in pancreatic cancer cells, and assessed the therapeutic potential of EGCG with gemcitabine or JAK3 inhibitor CP690550 (Tasocitinib) for the treatment and/or prevention of pancreatic cancer. Methodology/Principal Findings: Cell viability and apoptosis were measured by XTT assay and TUNEL staining, respectively. Gene and protein expressions were measured by qRT-PCR and Western blot analysis, respectively. The results revealed that EGCG inhibited the expression of phospho and total JAK3 and STAT3, STAT3 transcription and activation, and the expression of STAT3-regulated genes, resulting in the inhibition of cell motility, migration and invasion, and the induction of caspase-3 and PARP cleavage. The inhibition of STAT3 enhanced the inhibitory effects of EGCG on cell motility and viability. Additionally, gemcitabine and CP690550 alone inhibited STAT3 target genes and synergized with EGCG to inhibit cell viability and induce apoptosis in pancreatic cancer cells. Conclusions/Significance: Overall, these results suggest that EGCG suppresses the growth, invasion and migration of pancreatic cancer cells, and induces apoptosis by interfering with the STAT3 signaling pathway. Moreover, EGCG furthe

Protection by zinc against UVA - and UVB-induced cellular and genomic damage in vivo and in vitro

For many years, zinc salts have been used both topically and orally to treat minor burns and abrasions as well as to enhance wound repair in man and animals. In this study we describe the protective effects of zinc against UV-induced genotoxicity in vitro and against sunburn cell formation in mouse skin in vivo. Cultured skin cells from neonatal mice showed a dramatic increase in the number of micronuclei as a result of UVA and UVB irradiation. Inclusion of zinc at 5 μg/mL in the medium significantly reduced the frequency of micronuclei and of micronucleated cells. In hairless mice, topical application of zinc chloride for 5 consecutive days or a single application 2 h prior to UV exposure reduced the number of sunburn cells in the epidermis as did application of zinc 1 h after exposure. Application 2 h after irradiation also tended to have a protective effect, although there was a large variation between animals. It is proposed that an influx of zinc can protect epidermal cells against some of the more delayed effects of UV-induced damage.Record, Ian; Jannes, Mary; Dreosti, Ivo

Primary results from CECILIA, a global single-arm phase II study evaluating bevacizumab, carboplatin and paclitaxel for advanced cervical cancer

Objective: Adding bevacizumab to cisplatin\u2013paclitaxel for advanced cervical cancer significantly improves overall and progression-free survival. We evaluated bevacizumab with a widely used carboplatin\u2013paclitaxel backbone. Methods: Patients with metastatic/recurrent/persistent cervical cancer not amenable to curative surgery and/or radiotherapy received 3-weekly bevacizumab 15 mg/kg, paclitaxel 175 mg/m2, and carboplatin AUC 5 until progression or unacceptable toxicity. Maintenance bevacizumab was allowed. Patients with ongoing bladder/rectal involvement, prior cobalt radiotherapy, a history of fistula/gastrointestinal perforation, or recent bowel resection/chemoradiation were excluded. The primary objective was to determine incidences of gastrointestinal perforation/fistula, gastrointestinal-vaginal fistula, and genitourinary fistula. Results: Among 150 treated patients, disease at study entry was persistent in 21%, recurrent in 56%, and newly diagnosed metastatic in 23%. After 27.8 months' median follow-up, median bevacizumab duration was 6.7 months; 57% received maintenance bevacizumab. Seventeen patients (11.3%; 95% CI: 6.7\u201317.5%) experienced 651 perforation/fistula event: gastrointestinal perforation/fistula in 4.7% (1.9\u20139.4%), gastrointestinal-vaginal fistula in 4.0% (1.5\u20138.5%), and genitourinary fistula in 4.7% (1.9\u20139.4%). Of these, 16 were previously irradiated, several with ongoing radiation effects. The most common grade 3/4 adverse events were neutropenia (25%), anemia (19%), and hypertension (14%). Five patients (3%) had fatal adverse events. Objective response rate was 61% (95% CI: 52\u201369%), median progression-free survival was 10.9 (10.1\u201313.7) months, and median overall survival was 25.0 (20.9\u201330.4) months. Conclusions: Bevacizumab can be combined with carboplatin\u2013paclitaxel in the CECILIA study population. The fistula/gastrointestinal perforation incidence is in line with GOG-0240; efficacy results are encouraging. Trial registration number. NCT02467907 (ClinicalTrials.gov)