Intussusception of the small bowel secondary to malignant metastases in two 80-year-old people: a case series

<p>Abstract</p> <p>Introduction</p> <p>Small bowel intussusception is rare in adults and accounts for one percent of all bowel obstructions. Malignancy is the etiologic agent in approximately 50 percent of all cases.</p> <p>Case presentation</p> <p>Our first patient was an 80-year-old Caucasian woman with signs and symptoms of intermittent bowel obstruction for the last 12 months. Pre-operative investigation by abdominal computed tomography scanning revealed an obstruction at the ileocecal valve. Exploratory laparotomy revealed an ileocecal intussusception. She underwent an enterectomy. Histological examination showed metastatic breast cancer (lobular carcinoma). Our patient had previously undergone a mastectomy due to carcinoma three years earlier.</p> <p>Our second patient was an 80-year-old Caucasian man with signs and symptoms of acute bowel obstruction. Pre-operative investigation by abdominal computed tomography scanning showed an intussusception in the proximal part of the small bowel. Exploratory laparotomy revealed a jejunojejunal intussusception. He underwent an enterectomy. Histological examination showed metastatic melanoma. Our patient had a prior history of a primary cutaneous melanoma which was excised two years ago.</p> <p>Conclusion</p> <p>Pre-operative determination of the etiologic agent of intussusception in the small bowel in adults is difficult. Although a computed tomography scan is very helpful, the diagnosis of intussusception is made by exploratory laparotomy and histological examination defines the etiologic agent. A prior malignancy in the patient's history must be taken under consideration as a possible cause of intussusception.</p

New developments in RiPP discovery, enzymology and engineering

Ribosomally-synthesized and post-translationally modified peptides (RiPPs) are a large group of natural products. A community-driven review in 2013 described the emerging commonalities in the biosynthesis of RiPPs and the opportunities they offered for bioengineering and genome mining. Since then, the field has seen tremendous advances in understanding of the mechanisms by which nature assembles these compounds, in engineering their biosynthetic machinery for a wide range of applications, and in the discovery of entirely new RiPP families using bioinformatic tools developed specifically for this compound class. The First International Conference on RiPPs was held in 2019, and the meeting participants assembled the current review describing new developments since 2013. The review discusses the new classes of RiPPs that have been discovered, the advances in our understanding of the installation of both primary and secondary post-translational modifications, and the mechanisms by which the enzymes recognize the leader peptides in their substrates. In addition, genome mining tools used for RiPP discovery are discussed as well as various strategies for RiPP engineering. An outlook section presents directions for future research