Pseudomixoma peritonei associated with appendiceal cistoadenoma rupture: case report.

Appendiceal mucocele represents specimen finding in 0.2-0.3% out of appendectomies. The rupture or perforation in peritoneal cavity might cause pseudomixoma peritonei (PMP), with multiple mucinous deposits in the abdominal cavity. We report a case of PMP caused by a perforated appendiceal cistoadeonoma.

Mirizzi syndrome: a challenging diagnosis. Case report.

Mirizzi Syndrome (MS) is an uncommon complication of chronic gallstone disease defined as a common bile duct (CBD) obstruction secondary to gallstone impaction in the cystic duct or gallbladder neck. MS is still a challenging clinical situation: preoperative diagnosis of MS is complex and can be made in 18-62.5% of patients. Over 50% of patients with MS is diagnosed during surgery. In most of cases, laparotomy is the preferred surgical approach. We report the case of a 70-year-old woman with a history of asthenia, jaundice, abdominal pain and preoperative imaging that suggest the presence of biliary stones with a choledocal stenosis. Intraoperatively, a MS with cholecysto-biliary fistula involving less than two-thirds of the circumference of the bile duct was diagnosed and successfully treated.

Jejunal metastasis of Merkel cell carcinoma: case report.

Merkel cell carcinoma (MCC) of the skin is a rare but aggressive cutaneous neuroendocrine-derived malignancy that predominantly affects elderly white males. The presence of distant nodal metastases significantly impacts survival. Typical metastatic sites of MCC are liver, bone, brain and skin. Gastrointestinal metastases are uncommon and small bowel is the most common site followed by stomach. We report a case of symptomatic MCC jejunal metastasis.

Molecular evidence for genetic subdivision of Antarctic krill (Euphausia superba Dana) populations.

Antarctic krill (Euphausia superba Dana) is a key species in the Antarctic food web and occurs on a circumcontinental scale. Population genetic structure of this species was investigated by sequence analysis of the ND1 mitochondrial gene in four population samples collected at different geographical localities around the Antarctic continent. Results indicate the existence of significant genetic differences between samples, and we suggest that oceanographic barriers could be sufficiently strong and temporally stable to restrict gene flow between distinct areas. Moreover, our data indicate that Antarctic krill is not at mutation-drift equilibrium and that the species possibly has a low effective population size as compared to the census size.

Molecular evolution at subzero temperatures: mitochondrial and nuclear phylogenies of fishes from Antarctica (suborder Notothenioidei), and the evolution of antifreeze glycopeptides.

Most fishes of the perciform suborder Notothenioidei are endemic to the subzero marine waters of Antarctica. A number of remarkable physiological attributes allow them to inhabit this extreme environment; for example, the blood of almost all notothenioid species contains antifreeze glycopeptides. To establish a molecular phylogenetic hypothesis for these fishes, DNA sequences from two mitochondrial genes, portions of the 12S and 16S ribosomal genes (928 base pairs [bp]), were determined for 18 species. These belong to 15 genera in five families of the suborder. The DNA data suggest that two of these families are unnatural groups and consequently that the classification and phylogeny of this suborder is in need of revision. In terms of DNA variation, the Bovichtidae are a distantly related sister group to the other families of the suborder that includes the icefishes, the only vertebrates without hemoglobin. The fishes of the suborder (except the Bovichtidae) seem to have speciated rapidly, forming an adaptive radiation in the Antarctic waters. A phylogenetic analysis of published hemoglobin amino acid sequences for other notothenioid fishes supports these results from mtDNA. On the basis of molecular phylogeny, the evolution of antifreeze glycopeptides was studied. The age of the radiation of notothenioid fishes had been estimated to be at least 38 Mya. However, the level of mtDNA variation detected in notothenioid fishes appears to be too low to agree with this date of origin and might instead suggest a younger age (10-15 Mya). Alternatively, the low level of detected mtDNA variation would agree with the traditional old-age estimate if an extremely slow rate of mtDNA evolution is postulated for this group. This slow-rate hypothesis, if true, could be explained by decreased metabolic rates slowing down the tempo of molecular evolution.