Morphological Changes in the Midgut of Aedes aegypti L. (Diptera: Culicidae) Larvae Following Exposure to an Annona coriacea (Magnoliales: Annonaceae) Extract

Bioinsecticides are important in the control of disease vectors, but data regarding their physiological effects on target insects are incomplete. This study describes morphological changes that occur in the midgut of third instar Aedes aegypti L. (Diptera: Culicidae) following treatment with a methanolic extract of Annona coriacea (Magnoliales: Annonaceae). Dissected midguts were subdivided into anterior and posterior regions and analyzed by light and scanning electron microscopy. Insects exposed to the extract displayed intense, destructive cytoplasmic vacuolization in columnar and regenerative midgut cells. The apical surfaces of columnar cells exhibited cytoplasmic protrusions oriented toward the lumen, suggesting that these cells could be involved in apocrine secretory processes and/or apoptosis. We report that A. coriacea extracts induced morphological alterations in the midgut of A. aegypti midgut larvae, supporting the use of plant extracts for control of the dengue vector.     

Assessing the Revised Child Anxiety and Depression Scale (RCADS) in a national sample of Danish youth aged 8-16 years

Early identification of anxiety among youth is required to prevent them from going unrecognised and untreated by mental health professionals. A precise identification of the young person's primary difficulty is also required to guide treatment programs. Availability of a valid and easily administrable assessment tool is crucial for identifying youth suffering from anxiety disorders. The purpose of the present study was therefore to examine the psychometric properties of the Danish version of the Revised Children's Anxiety and Depression Scale (RCADS). A total of 667 youth from community schools (4(th) through 9(th) grade) across Denmark participated in the study. The psychometric properties of the RCADS-(DAN) resembled those reported in US and Europe. Within scale reliability was excellent with Chronbach's alpha of.96. All subscales also showed good to excellent internal reliability. The study provides convincing evidence that the RCADS-(DAN) is a valid assessment tool for screening anxiety in Danish youth.     

Model‐guided design of ligand‐regulated RNAi for programmable control of gene expression

Progress in constructing biological networks will rely on the development of more advanced components that can be predictably modified to yield optimal system performance. We have engineered an RNA‐based platform, which we call an shRNA switch, that provides for integrated ligand control of RNA interference (RNAi) by modular coupling of an aptamer, competing strand, and small hairpin (sh)RNA stem into a single component that links ligand concentration and target gene expression levels. A combined experimental and mathematical modelling approach identified multiple tuning strategies and moves towards a predictable framework for the forward design of shRNA switches. The utility of our platform is highlighted by the demonstration of fine‐tuning, multi‐input control, and model‐guided design of shRNA switches with an optimized dynamic range. Thus, shRNA switches can serve as an advanced component for the construction of complex biological systems and offer a controlled means of activating RNAi in disease therapeutics.     

Determination of fetal biparietal diameter without the use of ultrasound in squirrel monkeys

This study evaluated manual caliper measurement of fetal BPD in Saimiri through the abdomen of the dam (TBPD) for correlation with paired ultrasound measurements, prediction of delivery date, subspecies variation, prediction of pregnancy outcome, and correlation between postpartum BPD and TBPD. Regression analysis revealed a close relationship between TBPD measurements and those obtained by ultrasound (P < 0.001). TBPD for Saimiri boliviensis boliviensis increased from a mean of 14.8 ± 0.3 mm for 11 weeks prepartum to a delivery week measurement of 33.2 ± 0.2mm. Delivery-week TBPD of Saimiri boliviensis peruviensis were significantly smaller than Saimiri sciureus sciureus (P < .05). Delivery week TBPD had a correlation coefficient of 0.64 with paired post-patrum measurements. No complications were associated with the technique. Delivery date could be predicted within two weeks. TBPD is an inexpensive, safe, rapid method of approximating fetal growth during the last half of pregnancy in Saimiri.