Strigiformes are an order of raptorial birds consisting exclusively of owls: the Tytonidae (barn owls) and the Strigidae (true owls), united by a suite of adaptations aiding a keen predatory lifestyle, including robust hind limb elements modified for grip strength. To assess variation in hind limb morphology, we analysed how the dimensions of the major hind limb elements in subfossil and modern...

When it first appears at stage HH16, the wing bud is already polarized along the dorsoventral axis. To study the mechanisms leading to the establishment of its dorsoventral polarity, we decided to focus our attention on an earlier stage (HH13). Using the quail-chick chimera system, we first show that the presumptive wing mesoderm occupies the medial half of the somatopleure at the level of somi...

OBJECTIVE To determine the effect of weight reduction on clinical signs of lameness among overweight dogs with clinical and radiographic signs of hip osteoarthritis. DESIGN Nonblinded prospective clinical trial. ANIMALS 9 client-owned dogs with radiographic signs of hip osteoarthritis that weighed 11 to 12% greater than their ideal body weight and were examined because of hind limb lameness...

When polarizing mesoderm from the posterior border of the 4-day chick limb bud is placed adjacent to anterior limb mesoderm and ectodermal ridge, the anterior ridge thickens and mesodermal outgrowth ensues, resulting in supernumerary limb structures. This apposition of anterior and posterior limb tissues can be accomplished by cutting off the apical one third of the limb bud and reimplanting it...

Mutations in the murine limb deformity (ld) gene disrupt differentiation of the Apical Ectodermal Ridge (AER) and patterning of distal limb structures. However, initial outgrowth of the limb bud is not affected, suggesting that early and late functions of the AER are uncoupled. Similarly, activation of the 5' members of the HoxD gene cluster (Hoxd-11 to Hoxd-13) is not affected in ld mutant pos...

In vivo animal model systems, and in particular mouse models, have evolved into powerful and versatile scientific tools indispensable to basic and translational research in the field of transplantation medicine. A vast array of reagents is available exclusively in this setting, including mono- and polyclonal antibodies for both diagnostic and interventional applications. In addition, a vast num...

OBJECTIVE Adaptation to ischemia by brief episodes of ischemia and reperfusion (preconditioning) of the heart protects the heart against sustained ischemia, where the transcription factor nuclear factor kappa-B (NFkappaB) appears crucial for the protection. Preconditioning of the heart may even be evoked by brief episodes of ischemia and reperfusion in other organs. The present study investigat...

Vertebrate odd-skipped related genes (Osr) have an essential function during the formation of the intermediate mesoderm (IM) and the kidney structures derived from it. Here, we show that these genes are also crucial for limb bud formation in the adjacent lateral plate mesoderm (LPM). Reduction of zebrafish Osr function impairs fin development by the failure of tbx5a maintenance in the developin...

To investigate the role of fibroblast growth factor-2 (basic fibroblast growth factor) in chick limb development, we constructed a replication-defective spleen necrosis virus to ectopically express fibroblast growth factor-2 in stage 20-22 chick limb bud. Because infecting cells in vivo proved to be inefficient, limb bud cells were dissociated, infected in vitro, and then grafted back into host...

T H E limbs of amniote embryos are characterized by a thickening of the epiblast at their tips (Balfour, 1885). Kolliker (1879) illustrated such a thickening in a section of a chick embryo and, according to Braus (1906), was responsible for the term 'ectodermal cap' {Ektodermkappe). Saunders (1948) showed in the chick by experimental means that 'the thickened ectoderm at the apex of the bud' is...