Accuracy and reproducibility of voxel based superimposition of cone beam computed tomography models on the anterior cranial base and the zygomatic arches

Superimposition of serial Cone Beam Computed Tomography (CBCT) scans has become a valuable tool for three dimensional (3D) assessment of treatment effects and stability. Voxel based image registration is a newly developed semi-automated technique for superimposition and comparison of two CBCT scans. The accuracy and reproducibility of CBCT superimposition on the anterior cranial base or the zygomatic arches using voxel based image registration was tested in this study. 16 pairs of 3D CBCT models were constructed from pre and post treatment CBCT scans of 16 adult dysgnathic patients. Each pair was registered on the anterior cranial base three times and on the left zygomatic arch twice. Following each superimposition, the mean absolute distances between the 2 models were calculated at 4 regions: anterior cranial base, forehead, left and right zygomatic arches. The mean distances between the models ranged from 0.2 to 0.37 mm (SD 0.08-0.16) for the anterior cranial base registration and from 0.2 to 0.45 mm (SD 0.09-0.27) for the zygomatic arch registration. The mean differences between the two registration zones ranged between 0.12 to 0.19 mm at the 4 regions. Voxel based image registration on both zones could be considered as an accurate and a reproducible method for CBCT superimposition. The left zygomatic arch could be used as a stable structure for the superimposition of smaller field of view CBCT scans where the anterior cranial base is not visible.     

Autosomal dominant polycystic kidney disease: evidence for the existence of a third locus in a Portuguese family

Autosomal dominant polycystic kidney disease is characterized by clinical and genetic heterogeneity. Two loci implicated in the disease have previously been mapped (PKD1 on chromosome 16 and PKD2 on chromosome 4). By two point and multipoint linkage analysis, negative lod scores have been found for both chromosome 16 and chromosome 4 markers in a large Portuguese family, indicating that a third PKD locus is involved in the development of the disease.     

Chromosome 16 microdeletion in a patient with juvenile neuronal ceroid lipofuscinosis (Batten disease).

The gene that is involved in juvenile neuronal ceroid lipofuscinosis (JNCL), or Batten disease--CLN3--has been localized to 16p12, and the mutation shows a strong association with alleles of microsatellite markers D16S298, D16S299, and D16S288. Recently, haplotype analysis of a Batten patient from a consanguineous relationship indicated homozygosity for a D16S298 null allele. PCR analysis with different primers on DNA from the patient and his family suggests the presence of a cytogenetically undetectable deletion, which was confirmed by Southern blot analysis. The microdeletion is embedded in a region containing chromosome 16-specific repeated sequences. However, putative candidates for CLN3, members of the highly homologous sulfotransferase gene family, which are also present in this region in several copies, were not deleted in the patient. If the microdeletion in this patient is responsible for Batten disease, then we conclude that the sulfotransferase genes are probably not involved in JNCL. By use of markers and probes flanking D16S298, the maximum size of the microdeletion was determined to be approximately 29 kb. The microdeletion may affect the CLN3 gene, which is expected to be in close proximity to D16S298.     

Distribution of spring barley roots in Danish soils,of different texture and under different climatic conditions

Summary Spring barley root profiles have been investigated in three years with different climatological conditions during the growing season. In total, 50 root profiles were determined by measuring cm root/ml soil in different 10 cm sections of the profile. The investigations, show that the root density was nearly identical for all soil types within the upper part of the plough layer. The decrease in root density with depth is most pronounced for the sandy soils and less for the loamy soils. The mean max. root depth in the sandy soils was roughly 70 cm, while it was roughly 140 cm for the loamy soils. A comparison between the clay and silt content in the subsoil and the thickness of soil layers with more than given root densities shows that there is no correlation between texture and thickness of soil layers with more than 1.0 cm root/ml soil, while there was a clear, positive correlation between thickness of soil layers with lower root densities and the clay and silt content in the subsoil. The different climatological conditions during the growing season give rise to differences in the root development. Very wet springs seem to impede root development in loamy soils with slowly permeable subsoils, while this is not the case in the sandy soils.     

Significance of Ca2+, Rb+ fluxes, of cAMP and cGMP for the CCK8-modulated insulin release

In rat pancreatic islets the effects of cholecystokinin-8 (CCK8) on glucose-mediated insulin release, 45Ca2+ net uptake, 45Ca2+ efflux, 86Rb+ efflux, cAMP- and cGMP levels were studied. In the presence of a substimulatory glucose concentration (3 mM) CCK8 concentrations of up to 1 microM had no effect on insulin release, but CCK8 at 10 nM potentiated the stimulatory effect of glucose (11.1 mM). 10 nM CCK8 enhanced glucose-stimulated 45Ca2+ net uptake but was ineffective at substimulatory glucose levels. CCK8 had no effect on cAMP and cGMP levels in the presence of 11.1 mM glucose, CCK8 increased 86Rb+ (a measure of K+) in the presence of both 3 and 11.1 mM glucose. This effect was abolished when Ca2+ was omitted from the perifusion medium. CCK8 did not alter glucose (11.1 mM)-stimulated 45Ca2+ efflux rate. These data indicate that (1) CCK8 potentiates glucose-stimulated insulin secretion possibly via an effect on Ca2+ uptake, 2) by affecting Ca2+ uptake, CCK8 enhances K+ efflux, and 3) CCK8 does not mediate its effect via cAMP or cGMP. With respect to 86Rb+ efflux the mechanism of CCK8 action appears to be different from that of glucose. When the mechanism of CCK action on islets is compared with that on exocrine pancreas (data from others) there are similarities (importance of Ca2+ uptake and non-importance of cAMP and cGMP).     

Mutation detection in the repeated part of the PKD1 gene.

The principle cause of one of the most prevalent genetic disorders, autosomal dominant polycystic kidney disease, involves mutations in the PKD1 gene. However, since its identification in 1994, only 27 mutations have been published. Detection of mutations has been complicated because the greater part of the gene lies within a genomic region that is reiterated several times at another locus on chromosome 16. Amplification of DNA fragments in the repeated part of the PKD1 gene will lead to coamplification of highly homologous fragments derived from this other locus. These additional fragments severely hamper point-mutation detection. None of the point mutations published to date are located in the repeated part of the PKD1 gene. However, we have reduced the problems posed by the strong homology, by using the protein-truncation test, and we have identified eight novel mutations, seven of which are located in the repeated part of the PKD1 gene.