The arylhydrocarbon-receptor nuclear translocator (ARNT) is a member of the basic-helix-loop-helix-PAS family of heterodimeric transcription factors which includes the arylhydrocarbon receptor (AHR), hypoxia-inducible factor-1alpha (HIF-1alpha) and the Drosophila single-minded protein (Sim). ARNT forms heterodimeric complexes with the arylhydrocarbon receptor, HIF-1alpha, Sim and the PAS protein Per. In response to environmental pollutants, AHR-ARNT heterodimers regulate genes involved in the metabolism of xenobiotics, whereas ARNT-HIF-1alpha heterodimers probably regulate those involved in the response to oxygen deprivation. By generating a targeted disruption of the Arnt locus in the mouse, we show here that Arnt-/- embryonic stem cells fail to activate genes that normally respond to low oxygen tension. Arnt-/- ES cells also failed to respond to a decrease in glucose concentration, indicating that ARNT is crucial in the response to hypoxia and to hypoglycaemia. Arnt-/- embryos were not viable past embryonic day 10.5 and showed defective angiogenesis of the yolk sac and branchial arches, stunted development and embryo wasting. The defect in blood vessel formation in Arnt-/- yolk sacs is similar to the angiogenic abnormalities reported for mice deficient in vascular endothelial growth factor or tissue factor. On the basis of these findings, we propose a model in which increasing tissue mass during organogenesis leads to the formation of hypoxic/nutrient-deprived cells, the subsequent activation of ARNT, and a concomitant increase in the expression of genes (including that encoding vascular endothelial growth factor) that promote vascularization of the developing yolk sac and solid tissues.

Spi-B is a hematopoietic-specific Ets

To evaluate whether multiplex PCR-based molecular testing is noninferior to urine culture for detection of bacterial infections in symptomatic patients. METHODS Retrospective record review of 582 consecutive elderly patients presenting with symptoms of lower urinary tract infection (UTI) was conducted. All patients had traditional urine cultures and PCR molecular testing run in parallel. RESULTS A total of 582 patients (mean age 77; range 60-95) with symptoms of lower UTI had both urine cultures and diagnostic PCR between March and July 2018. PCR detected uropathogens in 326 patients (56%, 326/582), while urine culture detected pathogens in 217 patients (37%, 217/582). PCR and culture agreed in 74% of cases (431/582): both were positive in 34% of cases (196/582) and both were negative in 40% of cases (235/582). However, PCR and culture disagreed in 26% of cases (151/582): PCR was positive while culture was negative in 22% of cases (130/582), and culture was positive while PCR was negative in 4% of cases (21/582). Polymicrobial infections were reported in 175 patients (30%, 175/582), with PCR reporting 166 and culture reporting 39. Further, polymicrobial infections were identified in 67 patients (12%, 67/582) in which culture results were negative. Agreement between PCR and urine culture for positive cultures was 90%, exceeding the noninferiority threshold of 85% (95% conflict of interest 85.7%-93.6%). CONCLUSION Multiplex PCR is noninferior to urine culture for detection and identification of bacteria. Further investigation may show that the accuracy and speed of PCR to diagnose UTI can significantly improve patient outcomes. UROLOGY 136: 119−126, 2020.

The candidate proto-oncogene BCL3 was isolated through its involvement in the t(14;19) found in chronic lymphocytic leukemia and other B-cell neoplasms. As a member of the I kappaB family, BCL3 plays a role in the immune response by interactions with the NF-kappaB family of transcription factors. In order to study the role of BCL3 overexpression in lymphoid malignancies, we generated five lines of E mu-BCL3 transgenic mice. Transgenic animals develop normally but show splenomegaly and an accumulation of mature B cells in lymph nodes, bone marrow and peritoneal cavity. A hyperresponsive immune system is suggested by the follicular hyperplasia and plasmacytosis in lymph nodes of unimmunized animals, increased incidence of antibodies to self-antigens, and a heightened response to cross-linking of surface IgM. Statistically significant decreases in serum IgM and IgG3, but an increase in IgG1 and IgA were also observed. No lymphoid neoplasms have been identified in transgenic animals. The expansion of B cells in vivo is consistent with the overexpression of BCL3 as being one step in the multi-step process of leukemogenesis. The phenotype also suggests that BCL3 plays a part in B cell proliferation and isotype switching.

Context.—Correct diagnosis of the tissue origin of a metastatic cancer is the first step in disease management, but it is frequently difficult using standard pathologic methods. Microarray-based gene expression profiling has shown great promise as a new tool to address this challenge. Objective.—Adoption of microarray technologies in the clinic remains limited. We aimed to bridge this technological gap by developing a real-time quantitative polymerase chain reaction (RT-PCR) assay. Design.—We constructed a microarray database of 466 frozen and 112 formalin-fixed, paraffin-embedded (FFPE) samples of both primary and metastatic tumors, measuring expression of 22 000 genes. From the microarray database, we used a genetic algorithm to search for gene combinations optimal for multitumor classification. A 92-gene RT-PCR assay was then designed and used to generate a database for 481 frozen and 119 FFPE tumor samples. Results.—The microarray-based K-nearest neighbor classifier demonstrated 84% accuracy in classifying 39 tumor types via cross-validation and 82% accuracy in predicting 112 independent FFPE samples. We successfully translated the microarray database to the RT-PCR platform, which allowed an overall success rate of 87% in classifying 32 different tumor classes in the validation set of 119 FFPE tumor samples. Conclusions.—The RT-PCR-based expression assay involving 92 genes represents a powerful tool for accurately and objectively identifying the site of origin for metastatic tumors, especially in the cases of cancer of unknown primary. The assay uses RT-PCR and routine FFPE samples, making it suitable for rapid clinical adoption.