ABSTRACT
BACKGROUND: Despite the importance of the coronary system in the African sheep as a possible experimental model, there is little information about this particular vascular system. The objective of this investigation was to characterise morpho- logically the coronary arteries and their branches in African sheep. MATERIALS AND METHODS: This descriptive cross-sectional study evaluated the coronary arteries and their branches of 62 hearts of short hair sheep. The right and left coronary ostia were perfused with a semi-synthetic resin (Palatal GP40L 85%; styrene 15%) dyed with mineral red. The morphological characteristics were evaluated using a digital calibrator and the biometrics of the coronary arteries and their branches were registered. RESULTS: The right coronary artery had a proximal calibre of 2.11 ± 0.46 mm. The subsinusal interventricular branch ended at the middle third of the homonym sulcus in 19 (30.6%) specimens. The left coronary artery had a diameter of 5.38 ± ± 1.59 mm and a length of 4.67 ± 3.32 mm. This artery bifurcated itself in the paraconal interventricular branch and the left circumflex branch in 57 (91.9%) hearts and trifurcated with an additional left diagonal branch in 5 (8.1%) spec- imens. Left coronary artery dominance was observed in 51 (82.3%) specimens, whereas in 11 (17.7%) cases the coronary circulation dominance was balanced. CONCLUSIONS: Due to the similitude in the features of the coronary arteries between African sheep and humans, this animal model can be proposed for procedural and haemodynamic activities.
ABSTRACT
Translocations involving the X and Y chromosomes are often associated with anomalies of gonadal development. Transfer of Yp sequences, including the testis-determining SRY gene, to the terminal portion of the short arm of the X chromosome is associated with 46,XX maleness and in rare cases 46,XX true hermaphroditism. Three classes of XX males have been defined on the basis of the extent of Y material transferred to the X chromosome. In one class, the transfer of material involves aberrant recombination between two highly homologous genes, PKRX and PKRY, and there is evidence to suggest that this interchange is influenced by the Y chromosome background. Other types of X-Y translocations associated with anomalies of sex differentiation include Xp-Yq translocations, which result in a functional disomy of Xp sequences including the DSS locus and are associated with 46,XY complete or partial gonadal dysgenesis. In rare cases Yp-Xq translocations have been described in association with 46,XX maleness.
