Variation in digit number has occurred multiple times in the history of archosaur evolution. The five digits of dinosaur limbs were reduced to three in bird forelimbs, and were further reduced in the vestigial forelimbs of the emu. Regulation of digit number has been investigated previously by examining genes involved in anterior-posterior patterning in forelimb buds among emu ( Dromaius novaehollandiae ), chicken ( Gallus gallus ) and zebra finch ( Taeniopygia guttata ). It was described that the expression of posterior genes are conserved among these three birds, whereas expression of anterior genes Gli3 and Alx4 varied significantly. Here we re-examined the expression pattern of Gli3 and Alx4 in the forelimb of emu, chicken and zebra finch. We found that Gli3 is expressed in the anterior region, although its range varied among species, and that the expression pattern of Alx4 in forelimb buds is broadly conserved in a stage-specific manner. We also found that the dynamic expression pattern of the BMP antagonist Gremlin1 ( Grem1 ) in limb buds, which is critical for autopodial expansion, was consistent with the digital pattern of emu, chicken and zebra finch. Furthermore, in emu, variation among individuals was observed in the width of Grem1 expression in forelimb buds, as well as in the adult skeletal pattern. Our results support the view that the signalling system that regulates the dynamic expression of Grem1 in the limb bud contributes substantially to variations in avian digital patterns.
We have previously reported the presence of an apyrase in Mimosa pudica. However, only limited information is available for this enzyme. Thus, in this study, the apyrase was purified to homogeneity. The purified enzyme had a molecular mass of around 67 kD and was able to hydrolyze both nucleotide triphosphate and nucleotide diphosphate as substrates. The ratio of ATP to ADP hydrolysis velocity of the purified protein was 0.01 in the presence of calcium ion, showing extremely high substrate specificity toward ADP. Thus, we designated this novel apyrase as MP67. A cDNA clone of MP67 was obtained using primers designed from the amino acid sequence of trypsin-digested fragments of the protein. In addition, rapid amplification of cDNA ends-polymerase chain reaction was performed to clone a conventional apyrase (MpAPY2). Comparison of the deduced amino acid sequences showed that MP67 is similar to ecto-apyrases; however, it was distinct from conventional apyrase based on phylogenetic classification. MP67 and MpAPY2 were expressed in Escherichia coli, and the recombinant proteins were purified. The recombinant MP67 showed high substrate specificity toward ADP rather than ATP. A polyclonal antibody raised against the recombinant MP67 was used to examine the tissue distribution and localization of native MP67 in the plant. The results showed that MP67 was ubiquitously distributed in various tissues, most abundantly in leaves, and was localized to plasma membranes. Thus, MP67 is a novel ecto-apyrase with extremely high substrate specificity for ADP.
A total of 419 calculi in the upper urinary tract of 402 patients were treated by SWL with the EDAP LT-01 lithotripter from July 1988 to September 1989. Subcapsular hematomas resulted in 17 kidneys of 16 patients, an incidence of 4.1%. On CT scan, fractures with subcapsular hematomas were observed in nine kidneys, and a retroperitoneal hematoma was observed in one patient. There was no significant difference in stone location and size, grade of hydronephrosis, number of shock waves, applied energy, or post-treatment fever between the groups with and without hematomas. However, the hematoma group revealed significantly (P < 0.01) higher incidences of pretreatment hypertension (> 160/95 mm Hg) and use of antiplatelet agents. It is difficult to detect some disorders of blood coagulation in ordinary laboratory studies in patients receiving low dosages of antiplatelet agents; and many drugs including analgesic and anti-inflammatory agents, calcium antagonists, coronary vasodilators, antiplatelet agents, beta-blockers, and lipid-regulating agents have antiplatelet actions. Therefore, particular care should be taken in SWL when a patient is using those drugs.
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In vertebrates, two pairs of buds that give rise to the fore- and hindlimbs form at discrete positions along the rostral-caudal axis of the body. The mechanism responsible for the positioning of the limb buds is still largely unknown. Here we show a novel function for Cut homeobox transcription factor 2 (Cux2), the ortholog of Drosophila cut, in refining the forelimb field during chick development. Cux2 is expressed in the forelimb field before the emergence of the limb buds. Knocking down the expression of Cux2 using small interfering RNA (siRNA) resulted in a caudal shift of the forelimb bud, whereas misexpression of Cux2 or the constitutively active Cux2 - VP16 caused a rostral shift of the forelimb bud or reduction of the forelimb field along the anterior-posterior axis. Further functional analyses revealed that expression of Hoxb genes and retinaldehyde dehydrogenase 2 ( Raldh2 ), which are involved in limb positioning, are directly activated by Cux2 in the lateral plate mesoderm. Our data suggest that Cux2 in the lateral plate mesoderm refines the forelimb field via regulation of Raldh2 and Hoxb genes in chicken embryos.
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