Microscopic analysis of chromatin localization and dynamics in C. elegans

During development, the genome undergoes drastic reorganization within the nuclear space. To determine tridimensional genome folding, genome-wide techniques (damID/Hi-C) can be applied using cell populations, but these have to be calibrated using microscopy and single-cell analysis of gene positioning. Moreover, the dynamic behavior of chromatin has to be assessed on living samples. Combining fast stereotypic development with easy genetics and microscopy, the nematode C. elegans has become a model of choice in recent years to study changes in nuclear organization during cell fate acquisition. Here we present two complementary techniques to evaluate nuclear positioning of genes either by fluorescence in situ hybridization in fixed samples or in living worm embryos using the GFP-lacI/lacO chromatin-tagging system.

Three-dimensional study of nasopalatine canal morphology: a descriptive retrospective analysis using cone-beam computed tomography

PURPOSE For dental implant treatment planning and placement, a precise anatomic description of the nasopalatine canal (NC) is necessary. This descriptive retrospective study evaluated dimensions of the NC and buccal bone plate (BBP) and the tridimensional association of the anatomic variants of NC, using cone-beam computed tomography (CBCT). METHODS This study included 230 CBCTs. Sagittal slices were used for measurements of the NC and BBP and to evaluate shape and direction-course of the NC. Coronal slices were used to assess NC shape and axial slices to assess number of incisive foramina and foramina of Stenson. RESULTS Mean NC length was 12.34 ± 2.79 mm, statistically significant differences were detected between genders (p < 0.001). Mean BBP length was 20.87 ± 3.68 mm, statistically significant differences were found for the dental status (p < 0.001) and mean BBP width was 6.83 ± 1.28 mm, significant differences were detected between genders (p < 0.001). Mean nasopalatine angle was 73.33° ± 8.11°, significant differences were found in sagittal and coronal classifications. The most prevalent canal was: cylindrical sagittal shape (48.2 %); slanted-straight direction-course (57.6 %); Ya-type coronal shape (42.4 %); and one foramen incisive with two Stenson's foramina (1-2) (50.9 %). Sagittal shape was associated with sagittal direction-course (p < 0.001). Coronal shape was associated with axial classification (p < 0.001). CONCLUSIONS The NC anatomy is highly variable. Gender is related to the NC length and BBP width, while dental status is related to BBP length. There was an association between the different sagittal classifications of the NC and between the coronal shape and axial classification.

Analysis of behavioral changes in dairy cows associated with claw horn lesions

Detecting lame cows is important in improving animal welfare. Automated tools are potentially useful to enable identification and monitoring of lame cows. The goals of this study were to evaluate the suitability of various physiological and behavioral parameters to automatically detect lameness in dairy cows housed in a cubicle barn. Lame cows suffering from a claw horn lesion (sole ulcer or white line disease) of one claw of the same hind limb (n=32; group L) and 10 nonlame healthy cows (group C) were included in this study. Lying and standing behavior at night by tridimensional accelerometers, weight distribution between hind limbs by the 4-scale weighing platform, feeding behavior at night by the nose band sensor, and heart activity by the Polar device (Polar Electro Oy, Kempele, Finland) were assessed. Either the entire data set or parts of the data collected over a 48-h period were used for statistical analysis, depending upon the parameter in question. The standing time at night over 12 h and the limb weight ratio (LWR) were significantly higher in group C as compared with group L, whereas the lying time at night over 12 h, the mean limb difference (△weight), and the standard deviation (SD) of the weight applied on the limb taking less weight were significantly lower in group C as compared with group L. No significant difference was noted between the groups for the parameters of heart activity and feeding behavior at night. The locomotion score of cows in group L was positively correlated with the lying time and △weight, whereas it was negatively correlated with LWR and SD. The highest sensitivity (0.97) for lameness detection was found for the parameter SD [specificity of 0.80 and an area under the curve (AUC) of 0.84]. The highest specificity (0.90) for lameness detection was present for Δweight (sensitivity=0.78; AUC=0.88) and LWR (sensitivity=0.81; AUC=0.87). The model considering the data of SD together with lying time at night was the best predictor of cows being lame, accounting for 40% of the variation in the likelihood of a cow being lame (sensitivity=0.94; specificity=0.80; AUC=0.86). In conclusion, the data derived from the 4-scale-weighing platform, either alone or combined with the lying time at night over 12 h, represent the most valuable parameters for automated identification of lame cows suffering from a claw horn lesion of one individual hind limb.