An implanted 8-channel array coil for high-resolution macaque MRI at 3T.

An 8-channel receive coil array was constructed and implanted adjacent to the skull in a male rhesus monkey in order to improve the sensitivity of (functional) brain imaging. The permanent implant was part of an acrylic headpost assembly and only the coil element loop wires were implanted. The tuning, matching, and preamplifier circuitry was connected via a removable external assembly. Signal-to-noise ratio (SNR) and noise amplification for parallel imaging were compared to single-, 4-, and 8-channel external receive-only coils routinely used for macaque fMRI. In vivo measurements showed significantly improved SNR within the brain for the implanted versus the external coils. Within a region-of-interest covering the cerebral cortex, we observed a 5.4-, 3.6-fold, and 3.4-fold increase in SNR compared to the external single-, 4-, and 8-channel coils, respectively. In the center of the brain, the implanted array maintained a 2.4×, 2.5×, and 2.1× higher SNR, respectively compared to the external coils. The array performance was evaluated for anatomical, diffusion tensor and functional brain imaging. This study suggests that a stable implanted phased-array coil can be used in macaque MRI to substantially increase the spatial resolution for anatomical, diffusion tensor, and functional imaging.

[Orthodontics in general dental practice 6. Treatment of Angle Class II/1 malocclusions]. / Orthodontie in de algemene tandartspraktijk 6. Behandeling van Angle klasse II/1-malocclusies.

Four patients with a Class II/1 malocclusion were treated. Despite their common malocclusion, the 4 patients had a different skeletal and dentofacial structure, which resulted in four different treatments. Whether treatment is indicated and which treatment is preferable depends on many factors, such as expected jaw growth, the possibility of jaw adaptation, the motivation of the patient and his or her parents and psychological factors. In the case of children and young adolescents a Class II/1 malocclusion can be treated with orthopaedic appliances, in which case natural growth and adaptation mechanisms of the face and jaw are exercised in the correction. In treating these 4 patients, both functional and extra-oral orthopaedic appliances were used.

Exclusion of coding region mutations in MSX1, PAX9 and AXIN2 in eight patients with severe oligodontia phenotype.

PURPOSE: This paper describes the screening of eight patients with severe oligodontia for PAX9 and AXIN2 mutations. SUBJECTS AND METHODS: Anamnestic data and a panoramic radiograph were collected to study the phenotype of eight patients with oligodontia and their first-degree relatives. A blood sample was taken for a mutational screening for PAX9 and AXIN2 mutations. RESULTS: No mutations were discovered, but a unique nucleotide change in a conserved 5' flanking region of PAX9 was revealed. Earlier screening of the same patients for MSX1 mutations also had a negative outcome. CONCLUSIONS: Considering the discrepancy between the high incidence rate of agenesis and the relatively small number of reported causative mutations in PAX9, MSX1 and AXIN2 genes, the genetic contribution to oligodontia probably is much more heterogeneous than expected so far. Therefore negative results, like the present exclusion data, should be published more often in order to get a better appreciation of the relative contribution of these specific mutations causing oligodontia. In this context the exact number of tested probands also should be mentioned at all cases. Recent evidence of PAX9-MSX1 protein interactions in odontogenesis as well as other genes and developmental factors should receive more attention.