Rationale. Pneumonia is a leading cause of postoperative complication. Objective. To examine trends, factors, and mortality of postoperative pneumonia following major cancer surgery (MCS). Methods. From 1999 to 2009, patients undergoing major forms of MCS were identified using the Nationwide Inpatient Sample (NIS), a Healthcare Cost and Utilization Project (HCUP) subset, resulting in weighted 2,508,916 patients. Measurements. Determinants were examined using logistic regression analysis adjusted for clustering using generalized estimating equations. Results. From 1999 to 2009, 87,867 patients experienced pneumonia following MCS and prevalence increased by 29.7%. The estimated annual percent change (EAPC) of mortality after MCS was −2.4% (95% CI: −2.9 to −2.0, P < 0.001); the EAPC of mortality associated with pneumonia after MCS was −2.2% (95% CI: −3.6 to 0.9, P = 0.01). Characteristics associated with higher odds of pneumonia included older age, male, comorbidities, nonprivate insurance, lower income, hospital volume, urban, Northeast region, and nonteaching status. Pneumonia conferred a 6.3-fold higher odd of mortality. Conclusions. Increasing prevalence of pneumonia after MCS, associated with stable mortality rates, may result from either increased diagnosis or more stringent coding. We identified characteristics associated with pneumonia after MCS which could help identify at-risk patients in order to reduce pneumonia after MCS, as it greatly increases the odds of mortality.

The planar cell polarity (PCP) pathway controls the process of convergent extension (CE) during gastrulation and neural tube closure and has been implicated in the pathogenesis of neural tube defects (NTDs) in animal models and human cohorts. In this study, we analyzed the role of one core PCP gene PRICKLE1 in these malformations. We screened this gene in 810 unrelated NTD patients and identified 7 rare missense heterozygous mutations that were absent in all controls analyzed and predicted to be functionally deleterious using bioinformatics. Functional validation of 5 PRICKLE1 variants in a zebrafish model demonstrated that one variant, p.Arg682Cys, antagonized the CE phenotype induced by the wild-type zebrafish prickle1a in a dominant fashion. Our study demonstrates that PRICKLE1 could act as a predisposing factor to human NTDs and further expands our knowledge of the role of PCP genes in the pathogenesis of these malformations.

SUMMARY High-resolution crystallographic structures of multisubunit RNA polymerases (RNAPs) have increased our understanding of transcriptional mechanisms. Based on a thorough review of the literature, we have compiled the mutations affecting the function of multisubunit RNA polymerases, many of which having been generated and studied prior to the publication of the first high-resolution structure, and highlighted the positions of the altered amino acids in the structures of both the prokaryotic and eukaryotic enzymes. The observations support many previous hypotheses on the transcriptional process, including the implication of the bridge helix and the trigger loop in the processivity of RNAP, the importance of contacts between the RNAP jaw-lobe module and the downstream DNA in the establishment of a transcription bubble and selection of the transcription start site, the destabilizing effects of ppGpp on the open promoter complex, and the link between RNAP processivity and termination. This study also revealed novel, remarkable features of the RNA polymerase catalytic mechanisms that will require additional investigation, including the putative roles of fork loop 2 in the establishment of a transcription bubble, the trigger loop in start site selection, and the uncharacterized funnel domain in RNAP processivity.

RNA polymerase II (RNAP II) is the 12-subunit enzyme that synthesizes all mammalian mRNA (5, 58). Biochemical analyses have revealed that the transcription reaction involves a number of successive steps that lead to the formation of a pre-mRNA (19,38). In the first step, RNAP II locates promoter DNA and positions its catalytic center near the transcriptional initiation site of the promoter DNA. This first step proceeds through the formation of a preinitiation complex that contains, in addition to RNAP II, a number of general initiation factors, including TATA binding protein (TBP), TFIIB, TFIIF, TFIIE, and TFIIH. Assembly of the preinitiation complex requires specific binding of some general initiation factors to core promoter elements, such as binding of TBP to the TATA box (3), TFIIB to the TFIIB recognition element (29), and TAFs of TFIID to Inr (50) and the downstream promoter element (2). Formation of the preinitiation complex is accompanied by topological changes, including bending and wrapping of promoter DNA around the protein core of the complex (13,28,30,36,42,45). Recent evidence indicates that DNA wrapping during transcription initiation is required for the accurate positioning of the initiation site near the enzyme catalytic center and the induction of topological constraints essential for promoter melting (8, 42). In the second step, promoter DNA between nucleotides (nt) Ϫ9 and ϩ2 is melted in such a way that the template strand becomes accessible to NTP polymerization (21,23,26,57). Both TFIIF and TFIIE were shown to participate in promoter melting (22,39). Full open-complex formation requires the action of the ATP-dependent helicase activity of TFIIH (21, 23). Two distinct single-stranded DNA helicases, XPB/p89 and XPD/p80, have been identified as components of TFIIH (46-48, 53, 56). A major role in promoter DNA melting prior to initiation was attributed to XPB/p89 (27,54). During the third step, RNAP II enters a cycle of abortive initiation events in which the enzyme synthesizes many short 2-to 10-nt transcripts (21). A structural transition within the initiation complex, including a remodeling of the transcription bubble, occurs when RNAP II reaches register 11 and enters the processive phase of the transcription reaction (21). TFIIH is responsible for the melting of the template DNA during promoter escape (16,32,51) and for the phosphorylation of the RNAP II carboxy-terminal domain (10,31,49). Formation of the mRNA is completed through transcript elongation and is followed by termination of the transcription reaction.The availability of crystal structures for both eukaryotic (6, 7, 14, 15) and prokaryotic (4, 33, 34, 55, 59) RNAPs has been invaluable for the understanding of the many molecular features of the transcription reaction. For example, the structure of elongating RNAP II has revealed the position of the RNA-DNA duplex formed during the transcription reaction (15). The available structures support a model in which the DNA enters the enzyme through a channel formed by a pair of "jaws"...