Anatomic femorotibial changes associated with tibial plateau leveling osteotomy.

This prospective study evaluated anatomic femorotibial changes utilizing the relationship between the intercondylar notch and the intercondylar eminence following tibial plateau leveling osteotomy (TPLO). We hypothesized that TPLO results in anatomic alteration of the femorotibial joint. Pre- and post-operative computed tomography (CT) scans of cranial cruciate deficient stifle joints treated with TPLO were performed on 25 client-owned dogs. Computed tomography scans were performed at 3 different stifle angles: extension, 135° walking angle, and 90° of flexion. Tibial plateau leveling osteotomy did not result in a significant medial or lateral shift of the intercondylar eminence relative to the intercondylar notch. There was a significant cranial shift of the intercondylar eminence with the stifle in extension following TPLO. In addition, TPLO resulted in a significantly narrowed femorotibial joint space. The biomechanical effects of TPLO and medial meniscal release need to be further defined.

Changements fémoro-tibiaux anatomiques associés à une ostéotomie de nivellement du plateau tibial. Cette étude prospective a évalué les changements fémoro-tibiaux anatomiques en utilisant le lien entre l'échancrure intercondylienne et l'éminence intercondylienne après une ostéotomie de nivellement du plateau tibial (ONPT). Nous avons formulé l'hypothèse que l'ONPT produit une altération anatomique de l'articulation fémoro-tibiale. Des tomodensitogrammes des articulations déficientes du grasset du ligament cruciforme traitées à l'aide de l'ONPT ont été réalisés sur 25 chiens appartenant à des propriétaires. Les tomodensitogrammes ont été réalisés à 3 angles différents : extension, angle ambulatoire à 135° et flexion de 90°. L'ostéotomie de nivellement du plateau tibial n'a pas produit un mouvement médial ou latéral significatif de l'éminence intercondylienne en rapport avec l'échancrure intercondylienne. Il y avait un mouvement crânial significatif de l'éminence intercondylienne du grasset dans l'extension après l'ONPT. De plus, l'ONPT a produit une réduction importante de l'espace fémoro-tibial. Les effets biomécaniques de l'ONPT et du déclenchement du ménisque médial doivent être définis de manière plus précise.(Traduit par Isabelle Vallières).

Current models for starch synthesis and the sugary enhancer1 (se1) mutation in Zea mays.

Among the desirable quality traits essential for commercial production of fresh or processed sweet corn, kernel sugar content is universally important. In sweet corn genotypes the primary kernel sugar is sucrose, which is elevated at the expense of starch, particularly amylopectin. Sweet corn mutations have been traditionally divided into two classes. Generally speaking, class one mutations affect cytosolic reactions early in the process of starch synthesis, before starch is synthesized, and class two mutations affect reactions within the amyloplast directly involving starch granule assembly. Two widely used but previously unclassified mutations are sugary1 (su1) and sugary enhancer1 (se1). The se1 gene is a recessive modifier of su1; therefore, both genes require mutual discussion. This review provides current information about the su1 and se1 maize endosperm mutations and describes evidence further supporting previous suggestions that they fit criteria for categorization as class two mutants [Science 151 (1966) 341]. Information on the genetics and phenotype of se1 will be summarized and the hypothesized role of the se1 gene product discussed within the context of current models for starch synthesis in Zea mays L.