FDG-Avid Metastatic Non-Clear Cell Renal Cell Carcinoma Presenting as Intussusception.

ABSTRACT: A 47-year-old man with a history of metastatic non-clear cell left renal cell carcinoma, unclassified subtype, status post left radical nephrectomy 4 years prior, and treated with immunotherapy for approximately 2½ years, presented for 18 F-FDG PET/CT exam 7 months after immunotherapy was stopped. A contrast-enhanced CT exam performed 3 weeks prior demonstrated a new small bowel intussusception in the left upper quadrant. The PET/CT demonstrated focal FDG uptake in the segment of small bowel involved in the intussusception. Pathology from small bowel resection demonstrated metastatic renal cell carcinoma.

Myocardial Infarction and Cardiac Arrest During Acquisition of 18 F-FDG PET/CT.

ABSTRACT: An 83-year-old man with multiple myeloma and history of coronary artery disease and ischemic cardiomyopathy experienced cardiac arrest during the 18 F-FDG PET/CT examination. The patient had not yet been treated for multiple myeloma. The PET/CT demonstrated focal FDG uptake about the left anterior descending coronary artery. Diffuse intense FDG uptake in the liver and less than normal uptake in other organs of usual FDG distribution were also present, likely due to altered hemodynamics and heart failure in the setting of an acute coronary syndrome.

Isoprenylcysteine methylation and demethylation regulate abscisic acid signaling in Arabidopsis.

Isoprenylated proteins bear an isoprenylcysteine methyl ester at the C terminus. Although isoprenylated proteins have been implicated in meristem development and negative regulation of abscisic acid (ABA) signaling, the functional role of the terminal methyl group has not been described. Here, we show that transgenic Arabidopsis thaliana plants overproducing isoprenylcysteine methyltransferase (ICMT) exhibit ABA insensitivity in stomatal closure and seed germination assays, establishing ICMT as a negative regulator of ABA signaling. By contrast, transgenic plants overproducing isoprenylcysteine methylesterase (ICME) exhibit ABA hypersensitivity in stomatal closure and seed germination assays. Thus, ICME is a positive regulator of ABA signaling. To test the hypothesis that ABA signaling is under feedback regulation at the level of isoprenylcysteine methylation, we examined the effect of ABA on ICMT and ICME gene expression. Interestingly, ABA induces ICME gene expression, establishing a positive feedback loop whereby ABA promotes ABA responsiveness of plant cells via induction of ICME expression, which presumably results in the demethylation and inactivation of isoprenylated negative regulators of ABA signaling. These results suggest strategies for metabolic engineering of crop species for drought tolerance by targeted alterations in isoprenylcysteine methylation.