FGF receptors are required for proper axonal branch targeting in Drosophila.

Proper axonal branch growth and targeting are essential for establishing a hard-wired neural circuit. Here, we examined the role of Fibroblast Growth Factor Receptors (FGFRs) in axonal arbor development using loss of function and overexpression genetic analyses within single neurons. We used the invariant synaptic connectivity patterns of Drosophila mechanosensory neurons with their innate cleaning reflex responses as readouts for errors in synaptic targeting and circuit function. FGFR loss of function resulted in a decrease in axonal branch number and lengths, and overexpression of FGFRs resulted in ectopic branches and increased lengths. FGFR mutants produced stereotyped axonal targeting errors. Both loss of function and overexpression of FGFRs within the mechanosensory neuron decreased the animal's frequency of response to mechanosensory stimulation. Our results indicate that FGFRs promote axonal branch growth and proper branch targeting. Disrupting FGFRs results in miswiring and impaired neural circuit function.

Achilles-Mediated and Sex-Specific Regulation of Circadian mRNA Rhythms in Drosophila.

The circadian clock is an evolutionarily conserved mechanism that generates the rhythmic expression of downstream genes. The core circadian clock drives the expression of clock-controlled genes, which in turn play critical roles in carrying out many rhythmic physiological processes. Nevertheless, the molecular mechanisms by which clock output genes orchestrate rhythmic signals from the brain to peripheral tissues are largely unknown. Here we explored the role of one rhythmic gene, Achilles, in regulating the rhythmic transcriptome in the fly head. Achilles is a clock-controlled gene in Drosophila that encodes a putative RNA-binding protein. Achilles expression is found in neurons throughout the fly brain using fluorescence in situ hybridization (FISH), and legacy data suggest it is not expressed in core clock neurons. Together, these observations argue against a role for Achilles in regulating the core clock. To assess its impact on circadian mRNA rhythms, we performed RNA sequencing (RNAseq) to compare the rhythmic transcriptomes of control flies and those with diminished Achilles expression in all neurons. Consistent with previous studies, we observe dramatic upregulation of immune response genes upon knock-down of Achilles. Furthermore, many circadian mRNAs lose their rhythmicity in Achilles knock-down flies, suggesting that a subset of the rhythmic transcriptome is regulated either directly or indirectly by Achilles. These Achilles-mediated rhythms are observed in genes involved in immune function and in neuronal signaling, including Prosap, Nemy and Jhl-21. A comparison of RNAseq data from control flies reveals that only 42.7% of clock-controlled genes in the fly brain are rhythmic in both males and females. As mRNA rhythms of core clock genes are largely invariant between the sexes, this observation suggests that sex-specific mechanisms are an important, and heretofore under-appreciated, regulator of the rhythmic transcriptome.

Relative Validity and Reproducibility of a Food Frequency Questionnaire to Assess Nutrients and Food Groups of Relevance to the Gut Microbiota in Young Children.

Dietary fiber is an important nutrient for the gut microbiota, with different fiber fractions having different effects. The aim of this study was to determine the relative validity and reproducibility of a food frequency questionnaire (EAT5 FFQ) for measuring intake of fiber, and low and high fiber foods, in studies examining diet and gut microbiota in young children. One hundred parents of 5-year old children completed the 123-item EAT5 FFQ on two occasions four weeks apart. A 3-day weighed diet record (WDR) was completed on non-consecutive days between FFQ appointments. Mean correlations between the (randomly chosen) FFQ and WDR were acceptable for nutrient and food group intakes (r = 0.34 and r = 0.41 respectively). Gross misclassification was below chance (12.5%) for quartiles of nutrient (mean 5.7%) and food group (mean 5.1%) intake. 'Absolute values for surrogate categories' suggested the FFQ clearly differentiated between highest and lowest quartiles for all nutrients and food groups tested. Mean correlations between repeat administrations of the FFQ suggested very good reproducibility for nutrients (r = 0.83) and food groups (r = 0.80). The EAT5 FFQ appears to be an appropriate tool for investigating the intake of nutrients and food groups of relevance to the gut microbiota, and is the first FFQ validated to measure total, soluble and insoluble non-starch polysaccharide intakes in young children.

An in-vitro evaluation of three types of drug-eluting microspheres loaded with irinotecan.

To compare the mechanical and chemical properties of three commercially available microspheres loaded with irinotecan. LifePearl (200 µm), DC Bead (100-300 µm), and Tandem (100 µm) microspheres were loaded with irinotecan. For loading, elution, and stability determinations, irinotecan concentrations were quantified using validated high-performance liquid chromatography methods. In-vitro elution was performed over 24 h using a USP 4 dissolution apparatus. Diameter measurements were performed using light microscopy. Time in suspension was considered as the time required for the microspheres to vacate 1/3 of the volume. All three microsphere types rapidly loaded irinotecan, with more than 95% loading at 1 h. In-vitro elution of irinotecan was rapid for LifePearl and DC Bead microspheres, with more than 98% elution at 1 h, and delayed for Tandem microspheres, with about 70% elution at 6 h. After loading with irinotecan, the average diameter of LifePearl and DC Bead microspheres was reduced by 9 and 18%, respectively, and was unchanged for Tandem microspheres. All three microsphere types lost 4-6% of the loaded irinotecan almost immediately upon placement in contrast: water and contrast: 5% dextrose, but further losses were minimal over 2 weeks. LifePearl microspheres remained longer in suspension (392±23 s) compared with DC Bead (154±13 s, P<0.001) and Tandem (198±19 s, P<0.001) microspheres. All three microsphere types load irinotecan rapidly. LifePearl and DC Bead microspheres elute irinotecan rapidly. Elution is delayed with Tandem microspheres. LifePearl microspheres show the longest time in suspension.

An In Vitro Evaluation of Four Types of Drug-Eluting Microspheres Loaded with Doxorubicin.

PURPOSE: To compare in vitro properties of 4 drug-eluting embolic agents loaded with doxorubicin. MATERIALS AND METHODS: DC Bead (100-300 µm), LifePearl (200 µm), HepaSphere (30-60 µm), and Tandem (100 µm) microspheres were loaded with 40 mg/20 mL of doxorubicin per milliliter of microspheres. Loading, elution, diameter changes after loading, changes in the amount of doxorubicin loaded over 2 weeks in storage, and time in suspension were evaluated. RESULTS: All microspheres loaded > 99% doxorubicin within 1 hour. In vitro elution reached a plateau by 6 hours, with 30% ± 5, 21% ± 2, 8% ± 3, and 6% ± 0 of the loaded doxorubicin eluted for LifePearl, DC Bead, HepaSphere, and Tandem microspheres, respectively, with at least 1 statistically significant difference between at least 2 of the products in doxorubicin eluted at every time point. The times to elute 75% of the total released doxorubicin were 197, 139, 110, and 77 min for DC Bead, LifePearl, HepaSphere, and Tandem microspheres, respectively. The average diameters of LifePearl, DC Bead, and Tandem microspheres were reduced after loading by 24%, 20%, and 9%, respectively. After suspension in contrast medium, no changes were observed in doxorubicin loading over 2 wk. After loading, times in suspension were 8.4 min ± 0.2, 6.0 min ± 0.1, 3.1 min ± 0.2, and 2.9 min ± 0.3 for Tandem, LifePearl, DC Bead, and HepaSphere microspheres, respectively. CONCLUSIONS: Although drug-eluting embolic agents universally loaded doxorubicin within 1 hour, the elution amounts, rates of release, diameter shrinkage, and times in suspension varied by product.