Avenues for Investigating the Neural Crest and Its Derivatives in Non-model (Unconventional) Vertebrates: A Craniofacial Skeleton Perspective

One of the early, profound insights regarding the biology of the neural crest was the observation of its contribution to the skeletal structures of the cranium and jaws. The critical nature of these structures made the comparative analysis of the cranial neural crest and its derived structures essential investigative aims toward our understanding of the development and evolution of vertebrates and vertebrate-specific structures. Though classically applied to a relatively wide range of taxa in the nineteenth and early twentieth centuries, the application of traditional methodologies for complex comparative developmental and anatomical analyses subsequently become more limited by their time-consuming nature, resource scarcity, and a greater emphasis on the genetic and molecular regulation of patterning and morphogenesis in a select number of tractable model organisms. Recently, however, this trend has been reversed, and the value of genetic and molecular-based questions applied to non-model (unconventional) vertebrate organisms has been re-appreciated. This is particularly true of comparative investigations of cranial neural crest biology. Herein, we present methodologies for the analysis of the cranial neural crest and its structural derivatives employable in modern investigations of both model and unconventional vertebrate organisms

Routine histopathology for carcinoma in cholecystectomy specimens not evidence based: a systematic review

Routine histopathological examination of gallbladder specimens is mainly performed to identify unexpected gallbladder carcinoma (GBC). This systematic review assesses the prevalence and characteristics of GBC in cholecystectomy specimens. PubMed, EMBASE, Web of Science, and the Cochrane Library were searched for all articles reporting on the finding of GBC in cholecystectomy specimens. Of the 30 articles included, 20 were from Europe and the United States, and 10 were of Asian origin. In the Western studies, 276 cases of GBC were found in 61,542 specimens (median prevalence 0.4%, 95% confidence interval [CI] 0.3-0.6). Of these, 65% were expected pre- or intraoperatively. In the Asian studies, 344 cases of GBC were found in 37,365 specimens (median prevalence 1.2%, 95% CI 0.8-1.7). Of these, 45% were expected pre- or intraoperatively. In a subgroup analysis, identification of previously unexpected GBC affected treatment in only a minority of patients. In total, 72% of the patients received no further treatment and 32 patients (22%) received secondary surgery, of whom 15 patients survived at least 1 year. The histopathological finding of GBC after cholecystectomy appears to be a rare event. The prevalence of unexpected GBC was higher in Asian studies than in Western studies. The pre- and intraoperative sensitivity for this carcinoma is low. Moreover, the diagnosis of GBC at the time of histopathology is usually inconsequential. The results of this systematic review do not support routine histopathology of cholecystectomy specimens in clinical practic