Self-Immolative Activation of ß-Galactosidase-Responsive Probes for In Vivo MR Imaging in Mouse Models.

Our lab has developed a new series of self-immolative MR agents for the rapid detection of enzyme activity in mouse models expressing ß-galactosidase (ß-gal). We investigated two molecular architectures to create agents that detect ß-gal activity by modulating the coordination of water to GdIII . The first is an intermolecular approach, wherein we designed several structural isomers to maximize coordination of endogenous carbonate ions. The second involves an intramolecular mechanism for q modulation. We incorporated a pendant coordinating carboxylate ligand with a 2, 4, 6, or 8 carbon linker to saturate ligand coordination to the GdIII ion. This renders the agent ineffective. We show that one agent in particular (6-C pendant carboxylate) is an extremely effective MR reporter for the detection of enzyme activity in a mouse model expressing ß-gal.

A Case Suspended in Time: The Educational Value of Case Reports.

Although medical case reports have fallen out of favor in the era of the impact factor, there is a long tradition of using case reports for teaching and discovery. Some evidence indicates that writing case reports might improve medical students' critical thinking and writing skills and help prepare them for future scholarly work. From 2009 through 2015, students participating in the case reporting program at a VA hospital produced 250+ case reports, 35 abstracts, and 15 journal publications. Here, three medical students who published their case reports comment on what they learned from the experience. On the basis of their comments, the authors propose five educational benefits of case reporting: observation and pattern recognition skills; hypothesis-generating skills; understanding of patient-centered care; rhetorical versatility; and use of the case report as a rapidly publishable "mini-thesis," which could fulfill MD thesis or scholarly concentration requirements. The authors discuss the concept of the case report as a "hybrid narrative" with simultaneous medical and humanistic significance, and its potential use to teach students about their dual roles as engaged listeners and scientists. Finally, the authors consider the limitations and pitfalls of case reports, including patient confidentiality issues, overinterpretation, emphasis on the rare, and low initial publication rates. Case reports allow students to contribute to medical literature, learn useful scholarly skills, and participate in a tradition that links them with past generations of physicians. The authors conclude that the case report can be an effective teaching tool with a broad range of potential educational benefits.

Ultra-deep sequencing detects ovarian cancer cells in peritoneal fluid and reveals somatic TP53 mutations in noncancerous tissues.

Current sequencing methods are error-prone, which precludes the identification of low frequency mutations for early cancer detection. Duplex sequencing is a sequencing technology that decreases errors by scoring mutations present only in both strands of DNA. Our aim was to determine whether duplex sequencing could detect extremely rare cancer cells present in peritoneal fluid from women with high-grade serous ovarian carcinomas (HGSOCs). These aggressive cancers are typically diagnosed at a late stage and are characterized by TP53 mutations and peritoneal dissemination. We used duplex sequencing to analyze TP53 mutations in 17 peritoneal fluid samples from women with HGSOC and 20 from women without cancer. The tumor TP53 mutation was detected in 94% (16/17) of peritoneal fluid samples from women with HGSOC (frequency as low as 1 mutant per 24,736 normal genomes). Additionally, we detected extremely low frequency TP53 mutations (median mutant fraction 1/13,139) in peritoneal fluid from nearly all patients with and without cancer (35/37). These mutations were mostly deleterious, clustered in hotspots, increased with age, and were more abundant in women with cancer than in controls. The total burden of TP53 mutations in peritoneal fluid distinguished cancers from controls with 82% sensitivity (14/17) and 90% specificity (18/20). Age-associated, low frequency TP53 mutations were also found in 100% of peripheral blood samples from 15 women with and without ovarian cancer (none with hematologic disorder). Our results demonstrate the ability of duplex sequencing to detect rare cancer cells and provide evidence of widespread, low frequency, age-associated somatic TP53 mutation in noncancerous tissue.

Type B Lactic Acidosis in a Patient with Gastric Adenocarcinoma and Extensive Hepatic Metastases.

OBJECTIVE: We report the second case of gastric adenocarcinoma associated with type B lactic acidosis. CLINICAL PRESENTATION AND INTERVENTION: An 81-year-old man presenting with upper gastrointestinal bleeding was found to have an advanced gastric adenocarcinoma. He had persistently elevated serum lactate attributed to malignancy-associated type B lactic acidosis as a diagnosis of exclusion. As he remained clinically stable with a near-normal pH, his elevated lactate was not specifically treated. CONCLUSION: This patient had an unusual type B lactic acidosis associated with gastric cancer. In the absence of signs and symptoms of other etiologies of lactic acidosis, physicians should consider malignancy-associated type B lactic acidosis.

Systemic delivery of a novel liver-detargeted oncolytic adenovirus causes reduced liver toxicity but maintains the antitumor response in a breast cancer bone metastasis model.

We are interested in developing oncolytic adenoviruses for the treatment of bone metastasis of cancer. A key limitation of systemic delivery of oncolytic adenovirus type 5 (Ad5) is that the majority of the virus is taken up by the liver, causing liver damage and systemic toxicity. Given that Ad5 hexon binding with blood coagulation factor X is a key factor in liver sequestration, and that a rare serotype, Ad48, has a diminished capacity to bind with factor X, we have generated mHAd.luc2, a novel hexon-chimeric oncolytic adenovirus. To create mHAd.luc2, seven hypervariable regions of Ad5 hexon were substituted with the corresponding regions from Ad48. Compared with Ad5-based oncolytic virus Ad.luc2, intravenous injection of mHAd.luc2 into nude mice resulted in significantly reduced liver uptake. A single high dose (1.0×10(11) viral particles/mouse) of Ad.luc2 resulted in 100% animal death by day 3; whereas none of the mice died in the mHAd.luc2 group. Liver enzyme and liver pathology studies indicated that mHAd.luc2 induced significantly less liver toxicity compared with Ad.luc2. Both mHAd.luc2 and Ad.luc2 exhibited similar binding with breast tumor cells, whereas in the presence of factor X, mHAd.luc2 binding was reduced. Both mHAd.luc2 and Ad.luc2 had nearly equal replication potential in breast cancer cells in vitro. Intravenous injection of mHAd.luc2 and Ad.luc2 into nude mice bearing bone metastases resulted in uptake of the viruses into skeletal tumors, and induced significant inhibition of established bone metastases. Thus, liver-detargeted oncolytic adenovirus can be developed for the treatment of breast cancer bone metastasis.