Objective. Traditional nonsteroidal antiinflammatory drugs (NSAIDs) increase the risk of upper gastrointestinal (GI) bleeding/perforation, but the magnitude of this effect for coxibs in the general population and the degree of variability between individual NSAIDs is still under debate. This study was undertaken to assess the risk of upper GI bleeding/perforation among users of individual NSAIDs and to analyze the correlation between this risk and the degree of inhibition of whole blood cyclooxygenase 1 (COX-1) and COX-2 in vitro.Methods ‫؍‬ 0.34, P ‫؍‬ 0.058), but a profound and coincident inhibition (>80%) of both COX isozymes was associated with higher risk. NSAIDs with a long plasma half-life and with a slow-release formulation were associated with a greater risk than NSAIDs with a short half-life.Conclusion. The results of our analysis demonstrate that risk of upper GI bleeding/perforation varies between individual NSAIDs at the doses commonly used in the general population. Drugs that have a long half-life or slow-release formulation and/or are associated with profound and coincident inhibition of both COX isozymes are associated with a greater risk of upper GI bleeding/perforation.Traditional nonaspirin nonsteroidal antiinflammatory drugs (NSAIDs) have been shown to increase the risk of upper gastrointestinal (GI) bleeding/perforation (1). Because of the widespread use of NSAIDs as analgesic, antiinflammatory, and antipyretic drugs, their serious upper GI complications are a major public health concern. To reduce the morbidity associated with NSAIDs it is necessary to establish specific estimates for individual drugs and individual groups of patients with different risk profiles.

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The vertebrate posterior body is formed by a combination of the gastrulation movements that shape the head and anterior trunk and posterior specific cell behaviors. Here, we investigated whether genes that regulate cell movements during gastrulation [no tail(ntl)/brachyury, knypek (kny) and pipetail(ppt)/wnt5] interact to regulate posterior body morphogenesis. Both kny;ntl and ppt;ntl double mutant embryos exhibit synergistic trunk and tail shortening by early segmentation. Gene expression analysis in the compound mutants indicates that anteroposterior germ-layer patterning is largely normal and that the tail elongation defects are not due to failure to specify or maintain posterior tissues. Moreover, ntl interacts with ppt and knyto synergistically regulate the posterior expression of the gene encoding bone morphogenetic protein 4 (bmp4) but not of other known T-box genes,fibroblast growth factor genes or caudal genes. Examination of mitotic and apoptotic cells indicates that impaired tail elongation is not simply due to decreased cell proliferation or increased cell death. Cell tracing in ppt;ntl and kny;ntl mutants demonstrates that the ventral derived posterior tailbud progenitors move into the tailbud. However,gastrulation-like convergence and extension movements and cell movements within the posterior tailbud are impaired. Furthermore, subduction movements of cells into the mesendoderm are reduced in kny;ntl and ppt;ntl mutants. We propose that Ntl and the non-canonical Wnt pathway components Ppt and Kny function in parallel, partially redundant pathways to regulate posterior body development. Our work initiates the genetic dissection of posterior body morphogenesis and links genes to specific tail-forming movements. Moreover, we provide genetic evidence for the notion that tail development entails a continuation of mechanisms regulating gastrulation together with mechanisms unique to the posterior body.

The dorsal-ventral axis of vertebrate embryos is thought to be specified by a gradient of bone morphogenetic protein (BMP) activity, which, in part, arises through the interaction of dorsally expressed antagonists Chordin and Noggin with the ventralizing BMPs. The zebrafish mercedes(tm305), ogon(m60), and short tail(b180) mutations produce ventralized phenotypes, including expanded bmp2b/4 expression domains. We find that the three mutations are allelic and that the locus they define, renamed ogon (ogo), maps to linkage group 25. The ogo(m60) and ogo(b180) mutations are deficiencies and thus represent null alleles, whereas the ENU-induced allele ogo(tm305) retains partial function. Aspects of the ogo(m60) and ogo(tm305) mutant phenotypes are fully suppressed by overexpression of BMP antagonists. Moreover, swirl(tc300), a null mutation in bmp2b, is epistatic to ogo(m60) mutation, providing further evidence that ogo normally functions in a BMP-dependent manner. Embryonic patterning is highly sensitive to maternal and zygotic ogo gene dosage, especially when the level of zygotic chordin activity is also reduced. However, elimination of the zygotic activity of both genes does not result in a completely ventralized embryo. Thus, while ogo and chordin are required to limit activity of BMPs, additional mechanisms must exist to block these ventralizing signals. We have ruled out zebrafish noggin homologues as candidates for the ogo gene, including a newly identified gene, nog1, which is specifically expressed in the gastrula organizer. The results suggest that ogo encodes an as yet unidentified dorsalizing factor that mediates dorsoventral patterning by directly or indirectly antagonizing BMP activity.