Ruptured ectopic pregnancy presenting as an irreducible inguinal hernia.

An inguinal hernia that suddenly becomes irreducible may be secondary to a variety of other underlying conditions which can occasionally mislead the attending surgeon. Benign, inflammatory or neoplastic processes, as well as surgical emergencies such as intraperitoneal or retroperitoneal haemorrhage, have all been previously reported to mimic an inguinal hernia that suddenly becomes irreducible with or without clinical features of strangulation. We add an additional interesting presentation to this list in the form of a ruptured ectopic pregnancy, which is the first such case reported in the literature. A swelling in the groin may be much more complicated than it seems on superficial consideration and good clinical acumen is constantly required in managing such cases if a satisfactory outcome without any morbidity is to be expected.

Spontaneous pneumoperitoneum associated with colonic pseudo-obstruction.

Pneumoperitoneum is almost always pathognomonic of a perforated abdominal viscus requiring urgent surgical intervention. Spontaneous or non-surgical pneumoperitoneum is a rare clinical condition arising secondary to abdominal, thoracic, gynaecologic or idiopathic causes. In addition to good clinical judgement, an important component in the management process is to rule out other causes of pneumoperitoneum by performing appropriate investigations. We describe a 60-year-old man who presented with clinical features of pseudo-obstruction, following an injury to his back which was compounded by hypokalaemia. Roentgenography revealed massive pneumoperitoneum and colonic distension. As there were no overt clinical features of peritonitis, the patient was managed conservatively with parenteral nutrition and close observation. A water-soluble contrast enema and computed tomography of the abdomen were of no help in identifying the cause of his pneumoperitoneum but were helpful in eliminating the presence of hollow viscus perforation or an obvious inflammatory focus. The aetiology of pneumoperitoneum in our patient was most likely due to dissection of air through the distended colonic wall, secondary to large bowel pseudo-obstruction. The diagnosis of spontaneous or non-surgical pneumoperitoneum is one of exclusion and we stress the importance of relying on clinical parameters when managing such patients conservatively.

Primary malignant melanoma of the oesophagus.

Primary malignant melanoma arising in the oesophagus is a rare condition with a dismal prognosis. The diagnosis is often made following surgical resection even though the endoscopic features may be pathognomonic. The classical treatment is oesophagectomy even though the advanced disease stage at the time of presentation and aggressive biological behaviour of the tumour usually results in a fatal outcome. We report the case of a male patient initially diagnosed with squamous oesophageal carcinoma and treated with conventional neo-adjuvant chemo-radiotherapy. Poor clinical and radiological response resulted in a review of the original histology confirming a diagnosis of primary malignant melanoma of the oesophagus. The subsequent alteration in management conferred the patient an improved quality of life. A short review of the literature on primary malignant melanoma of the oesophagus supplements this case report.

Structural basis for recognition of the translocated intimin receptor (Tir) by intimin from enteropathogenic Escherichia coli.

Intimin is a bacterial adhesion molecule involved in intimate attachment of enteropathogenic and enterohaemorrhagic Escherichia coli to mammalian host cells. Intimin targets the translocated intimin receptor (Tir), which is exported by the bacteria and integrated into the host cell plasma membrane. In this study we localized the Tir-binding region of intimin to the C-terminal 190 amino acids (Int190). We have also determined the region's high-resolution solution structure, which comprises an immunoglobulin domain that is intimately coupled to a novel C-type lectin domain. This fragment, which is necessary and sufficient for Tir interaction, defines a new super domain in intimin that exhibits striking structural similarity to the integrin-binding domain of the Yersinia invasin and C-type lectin families. The extracellular portion of intimin comprises an articulated rod of immunoglobulin domains extending from the bacterium surface, conveying a highly accessible 'adhesive tip' to the target cell. The interpretation of NMR-titration and mutagenesis data has enabled us to identify, for the first time, the binding site for Tir, which is located at the extremity of the Int190 moiety.

Structure of the cell-adhesion fragment of intimin from enteropathogenic Escherichia coli.

Enteropathogenic Escherichia coli (EPEC) induce gross cytoskeletal rearrangement within epithelial cells, immediately beneath the attached bacterium. The C-terminal 280 amino acid residues of intimin (Int280; 30.1 kDa), a bacterial cell-adhesion molecule, mediate the intimate bacterial host-cell interaction. Recently, interest in this process has been stimulated by the discovery that the bacterial intimin receptor protein (Tir) is translocated into the host cell membrane, phosphorylated, and after binding intimin triggers the intimate attachment. Using multidimensional nuclear magnetic resonance (NMR) and combining perdeuteration with site-specific protonation of methyl groups, we have determined the global fold of Int280. This represents one of the largest, non-oligomeric protein structures to be determined by NMR that has not been previously resolved by X-ray crystallography. Int280 comprises three domains; two immunoglobulin-like domains and a C-type lectin-like module, which define a new family of bacterial adhesion molecules. These findings also imply that carbohydrate recognition may be important in intimin-mediated cell adhesion.