developing supernumerary limbs is a rare congenital condition that only a few cases have been documented. depending on the cause and developmental conditions, they may be single, multiple or complicated, and occur as a syndrome or associated with other anomalies. polymelia is defined as the presence of extra limb(s) which have been reported in human, mouse, chicken, calf and lamb. it seems that...

introduction: depending on mode, intensity and length of application, and stage of development, the low-frequency electromagnetic fields (lfes) can induce a wide variety of biological effects in organisms. the chick limb bud is a powerful experimental system for study pattern formation in vertebrate embryo. the aim of this study was to examine the effects of an application lfes (50hz, 50g) on c...

introduction: oxidative stress has been implicated in the pathogenesis of various diseases affecting chondrogenesis or the function of articular cartilage. the purpose of the present study was to find the effect of soybean extract on reduction of detoriation effects of oxidativestress in embryonic chondrogenesis in vitro. methods: in order to separate ectoderm from mesenchyme, the limb buds of ...

Scatter factor/hepatocyte growth factor (SF/HGF) is known to be involved in the detachment of myogenic precursor cells from the lateral dermomyotomes and their subsequent migration into the newly formed limb buds. As yet, however, nothing has been known about the role of the persistent expression of SF/HGF in the limb bud mesenchyme during later stages of limb bud development. To test for a pot...

Hereditary Multiple Malformation (HMM) is a naturally occurring, autosomal recessive, homozygous lethal mutation found in Japanese quail. Homozygote embryos (hmm-/-) show polydactyly similar to talpid2 and talpid3 mutants. Here we characterize the molecular profile of the hmm-/- limb bud and identify the cellular mechanisms that cause its polydactyly. The hmm-/- limb bud shows a severe lack of ...

BACKGROUND Retinoic acid (RA) is present in the chick limb bud, and excess RA induces limb duplications. Here, we have investigated the role of endogenous RA during chick limb development by preventing the synthesis of RA and testing the effect on various genes expressed during limb initiation and outgrowth. RESULTS We demonstrate that the stage 20/21 limb bud synthesizes didehydroretinoic ac...

Outgrowth of normal chick limb bud mesoderm is dependent on the presence of a specialized epithelium called the apical ectodermal ridge. This ectodermal ridge is induced by the mesoderm at about the time of limb bud formation. The limbless mutation in the chick affects apical ectodermal ridge formation in the limb buds of homozygotes. The initial formation of the limb bud appears to be unaffect...

BACKGROUND The outgrowth of the vertebrate limb bud is the result of a reciprocal interaction between the mesenchyme and a specialized region of the ectoderm, the apical ectodermal ridge (AER), which overlies it. Signals emanating from the AER act to maintain the underlying mesenchyme, called the progress zone, in a highly proliferative and undifferentiated state. Removal of the AER results in ...

The undifferentiated vertebrate limb bud is a selforganizing system. If transplanted to a favorable ectopic location, the limb bud is capable of developing into a morphologically normal limb (Harrison, 1918), and the anterior-posterior polarity of the transplanted limb is determined by the graft rather than the host environment. Great progress has recently been made in understanding the molecul...