Differential in vivo tumorigenicity of diverse KRAS mutations in vertebrate pancreas: A comprehensive survey.

Somatic activation of the KRAS proto-oncogene is evident in almost all pancreatic cancers, and appears to represent an initiating event. These mutations occur primarily at codon 12 and less frequently at codons 13 and 61. Although some studies have suggested that different KRAS mutations may have variable oncogenic properties, to date there has been no comprehensive functional comparison of multiple KRAS mutations in an in vivo vertebrate tumorigenesis system. We generated a Gal4/UAS-based zebrafish model of pancreatic tumorigenesis in which the pancreatic expression of UAS-regulated oncogenes is driven by a ptf1a:Gal4-VP16 driver line. This system allowed us to rapidly compare the ability of 12 different KRAS mutations (G12A, G12C, G12D, G12F, G12R, G12S, G12V, G13C, G13D, Q61L, Q61R and A146T) to drive pancreatic tumorigenesis in vivo. Among fish injected with one of five KRAS mutations reported in other tumor types but not in human pancreatic cancer, 2/79 (2.5%) developed pancreatic tumors, with both tumors arising in fish injected with A146T. In contrast, among fish injected with one of seven KRAS mutations known to occur in human pancreatic cancer, 22/106 (20.8%) developed pancreatic cancer. All eight tumorigenic KRAS mutations were associated with downstream MAPK/ERK pathway activation in preneoplastic pancreatic epithelium, whereas nontumorigenic mutations were not. These results suggest that the spectrum of KRAS mutations observed in human pancreatic cancer reflects selection based on variable tumorigenic capacities, including the ability to activate MAPK/ERK signaling.

Urinary tract infections.

Women between the ages of 18 years and 64 years with the easiest-to-treat UTIs average 1.07 office visits, 2.36 prescriptions, and 2.34 laboratory and pathology services per PTE. Laboratory services were performed an average of 2.27 times per PTE on an outpatient basis. This patient group did not receive a significant amount of hospital admissions or professional inpatient services. Approximately 71% of all PTEs were treated with pharmaceutical therapy. Of the overall charges for UTIs, 31% were for prescription drug therapy. Of those patients treated with a single drug group, almost 33% were treated with trimethoprim/sulfamethoxazole and 13.2% were treated with a fluoroquinolone. Considering the potential cost savings of encouraging adherence to clinical prescribing guidelines, further investigation of physician prescribing patterns for uncomplicated UTIs may prove valuable to health plans.

Evolution of the scrambled germline gene encoding alpha-telomere binding protein in three hypotrichous ciliates.

The micronuclear genes encoding alpha-telomere-binding protein (alphaTP) in Oxytricha trifallax and Stylonychia mytilus contain multiple internal eliminated segments, or IESs, that divide the gene into multiple parts called macronuclear destined segments, or MDSs. The MDSs have become disordered, or scrambled, during evolution. The scrambled structures of the alphaTP genes in Oxytricha trifallax and S. mytilus have been compared with the previously published scrambled structure of the alphaTP gene in O. nova. The scrambled patterns of the alphaTP gene in the three species are similar but show significant differences. The micronuclear genes in O. nova and S. mytilus consist of 13 IESs and 14 MDSs, but the gene in O. trifallax is divided into three additional MDSs by the presence of three additional IESs, believed to have been inserted into the O. trifallax alphaTP gene after divergence of O. trifallax from the other two species. Corresponding IESs among the three species have shifted along the DNA during evolution, presumably by a mutational mechanism that changes the short repeat sequences that flank IESs. The IESs also have changed markedly in length by insertion and/or deletion of nucleotides. Comparison of the putative alphaTP amino acid sequences in the three species reveals three conserved and three nonconserved domains. The 5' nontranslated regions of the gene-sized molecules encoding alphaTP contain several conserved segments, and the 3' nontranscribed trailer contains one conserved segment.