Rural WA cancer patients experience significant OOPE following their diagnosis. The impact these expenses have on patient wellbeing and their treatment decisions need to be further explored.
In this work, we examined the regulation by GTP and UTP of the UMP kinases from eight bacterial species. The enzyme from Gram-positive organisms exhibited cooperative kinetics with ATP as substrate. GTP decreased this cooperativity and increased the affinity for ATP. UTP had the opposite effect, as it decreased the enzyme affinity for ATP. The nucleotide analogs 5-bromo-UTP and 5-iodo-UTP were 5-10 times stronger inhibitors than the parent compound. On the other hand, UMP kinases from the Gram-negative organisms did not show cooperativity in substrate binding and catalysis. Activation by GTP resulted mainly from the reversal of inhibition caused by excess UMP, and inhibition by UTP was accompanied by a strong increase in the apparent K m for UMP. Altogether, these results indicate that, depending on the bacteria considered, GTP and UTP interact with different enzyme recognition sites. In Grampositive bacteria, GTP and UTP bind to a single site or largely overlapping sites, shifting the T % R equilibrium to either the R or T form, a scenario corresponding to almost all regulatory proteins, commonly called K systems. In Gram-negative organisms, the GTP-binding site corresponds to the unique allosteric site of the Gram-positive bacteria. In contrast, UTP interacts cooperatively with a site that overlaps the catalytic center, i.e. the UMP-binding site and part of the ATP-binding site. These characteristics make UTP an original regulator of UMP kinases from Gram-negative organisms, beyond the common scheme of allosteric control.Bacterial UMP kinases represent a particular subfamily of NMP 2 kinases (1, 2). They do not share any significant sequence homology with other known NMP kinases and exist in solution as stable hexamers. A first structural model of Escherichia coli UMP kinase (3) based on the conservation of the carbamate kinase and N-acetylglutamate kinase folds (4, 5) helped to better rationalize previous site-directed mutagenesis experiments (6). The crystal structure of E. coli UMP kinase (7) indicated a similar fold between its monomers and N-acetylglutamate kinase, a dimeric enzyme (4, 5). However, the quaternary structure assembly of these two proteins is completely different (7). Deposited crystal structures of UMP kinases from other bacteria such as Pyrococcus furiosus (8), Neisseria meningitidis (Protein Data Bank code 1YBD), Hemophilus influenzae (code 2AIF), and Streptococcus pyogenes (code 1Z9D) show threedimensional structures very similar to that of the E. coli enzyme. The residues essential for binding nucleotide substrates and catalysis are conserved among all bacterial UMP kinases ( Fig. 1) (3, 9). Consequently, the active sites of these enzymes and the phosphoryl transfer mechanisms are most probably similar.Comparison of the biochemical properties of recombinant UMP kinases from Gram-negative E. coli (1, 2) and Gram-positive Streptococcus pneumoniae (10) indicated significant differences in their kinetic properties particularly in their regulation by nucleotides. Unlike the E. coli enzyme, U...
Peer review of cancer MDTs is feasible and acceptable. We describe valuable lessons learnt and recognise that further development of the proposed peer-review model and national benchmarking of MDTs against established outcome measures is required if this process is to be widely implemented.
BackgroundUtilisation of endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) and guide sheath (EBUS-GS) for diagnosis and staging of lung cancer is gaining popularity, however, its impact on clinical practice is unclear. This study aimed to determine the impact of the introduction of endobronchial ultrasound-guided procedures (EBUS) on time to management decision for lung cancer patients, and on the utilisation of other invasive diagnostic modalities, including CT-guided trans-thoracic needle aspiration (CT-TTNA), bronchoscopy, and mediastinoscopy.MethodsHospital records of new primary lung cancer patients presenting in 2007 and 2008 (Pre-EBUS cohort) and in 2010 and 2011 (Post-EBUS cohort) were reviewed retrospectively.ResultsThe Pre-EBUS cohort included 234 patients. Of the 326 patients in the Post-EBUS cohort, 90 had an EBUS procedure (EBUS-TBNA for 19.0 % and EBUS-GS for 10.4 % of cases). The number of CT-TTNAs and bronchoscopies decreased following the introduction of EBUS (p = 0.015 and p < 0.001 respectively). Of 162 CT-TTNAs, 59 (36 %) resulted in complications compared to 1 complication each for bronchoscopy and EBUS-GS, and no complications from EBUS-TBNA. Fewer complications occurred overall in the Post-EBUS cohort compared to the Pre-EBUS cohort (p = 0.0264). The median time to management decision was 17 days (IQR 24) for the Pre-EBUS and 13 days (IQR 21) for the Post-EBUS cohort (p = 0.07). Within the Post-EBUS cohort, median time to management decision was longer for the EBUS group (n = 90) than the Non-EBUS group (17 days (IQR 29) vs. 10 days (IQR 10), p < 0.001). For half of EBUS-TBNA patients (n = 28, 50.0 %) and EBUS-GS patients (n = 14, 50.0 %), EBUS alone provided sufficient diagnostic and/or staging information; these patients had median time to management decision of 10 days. Regression analysis revealed that the number of imaging events, inpatient, and outpatient visits were significant predictors of time to management decision of >28 days; EBUS was not a predictor of time to management decision.ConclusionsThe introduction of EBUS led to fewer CT-TTNAs and bronchoscopies and did not impact on the time to management decision. EBUS-TBNA or EBUS-GS alone provided sufficient information for diagnosis and/or regional staging in half of the lung cancer patients referred for this investigation.
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