Current process and outcomes of the surgical management of LUTS due to benign prostatic enlargement: how consistent are we? - results from the multi-institutional audit of surgical management of BPE (AuSuM BPE) in the United Kingdom.

OBJECTIVE: In view of changing landscape of surgical treatment for LUTS secondary to BPE, this audit was undertaken to assess key aspects of the processes and outcomes of the current interventional treatments for BPE, across different units in the UK. MATERIALS AND METHOD: A multi-institutional snapshot audit was conducted for patients undergoing interventions for LUTS/BPE over 8-week period. Using Delphi process two-part proforma was designed to capture data. RESULTS: 529 patients were included across 20 NHS trusts in England and Wales. Median age was 73 years. Indications for surgery were acute retention (47%) and LUTS (45%). 80% of patients had prior medical therapy. TURP formed the commonest procedure. 27% patients had <23 hour hospital stay. Immediate (21%) and delayed (18%) complications were Clavien-Dindo <2 category. High proportion of patients reported residual symptoms. Type and indication of surgery were significant predictor of complications, length of stay and failure of TWOC outcomes, on multivariate analyses. There were variations in departmental processes, 50% centres used PROMs. CONCLUSION: Monopolar TURP still remains the commonest intervention for BPE. Most departments are adopting newer technologies. The audit identified opportunities for development of consistent, effective and patient centric practices as well as need for large-scale focused studies.

Pilot-scale evaluation of semi-passive treatment technologies for the treatment of septage under temperate climate conditions.

Population growth in rural Canada has resulted in an increase in municipal septage generation, which could overload existing treatment facilities that rely on biological treatment approaches. To address concerns associated with potential shock loading of these systems, three semi-passive wastewater treatment technologies were compared at the pilot-scale to identify a suitable approach to augment the capacity of an existing wastewater stabilization pond facility in rural Ontario. Two of these technologies, the BioDome and BioCord systems, were commercially available systems that make use of biofilm technology to improve treatment performance and enhance the robustness to temperature and hydraulic loading fluctuations. The third approach involved the use of the natural filtration capacity of zebra mussels to improve effluent quality. The three technologies were assessed against a control for reductions in regulated wastewater parameters with an emphasis on nutrient (ammonia/ammonium, orthophosphate) reductions, air cycling, energy consumption, and performance following exposure to anoxic conditions. The BioCord system was the only technology that was found to significantly outperform the control, exhibiting reductions of 69%, 47%, 77% and 81% for NH3/NH4+, TN, COD and TSS, respectively. The BioCord system also had the lowest maintenance and energy requirements, likely due to its design, which provided the biofilm with optimal oxygen and substrate contact. Consequently, the BioCord system could develop a more stable, heterogeneous microbial population and maintain high levels of activity in its biofilm, even during periods of extended anaerobic conditions. This also suggested that the BioCord system would require less aeration, and hence a lower energy expenditure, than the other systems. Furthermore, the BioCord system showed the fastest rates of recovery, reaching significant levels of parameter reductions within one week of system re-initiation.

Sequential bacillus Calmette-Guérin/Electromotive Drug Administration of Mitomycin C as the Standard Intravesical Regimen in High Risk Nonmuscle Invasive Bladder Cancer: 2-Year Outcomes.

PURPOSE: Sequential bacillus Calmette-Guérin/electromotive drug administration of mitomycin C is reported to be superior to bacillus Calmette-Guérin alone but it has not been widely adopted. We aimed to determine the efficacy and tolerability of sequential bacillus Calmette-Guérin/electromotive drug administration of mitomycin C in high risk, nonmuscle invasive bladder cancer. MATERIALS AND METHODS: Starting in 2009 bacillus Calmette-Guérin/electromotive drug administration of mitomycin C was introduced as the standard induction regime in patients with high risk, nonmuscle invasive bladder cancer undergoing bladder conservation. As induction bacillus Calmette-Guérin was administered in weeks 1 and 2. Mitomycin C was administered in electromotive fashion (40 mg and 20 mA current for 30 minutes) in week 3 and repeated thrice for a total of 9 weeks. As maintenance 3 doses of bacillus Calmette-Guérin were given 3 months after induction and then every 6 months for 3 years. Outcome measures were disease recurrence at first check, 1 and 2-year cystoscopy, and treatment tolerability. RESULTS: Of the 151 patients with high risk, nonmuscle invasive bladder cancer treated between June 2009 and 2013, 44 underwent primary cystectomy and 107 received sequential bacillus Calmette-Guérin/electromotive drug administration of mitomycin C. Disease was high grade Ta/T1 in 86 patients (80%), of whom 34 (32%) also had carcinoma in situ. A total of 19 patients (18%) had primary carcinoma in situ and 2 had recurrent large volume, low grade disease. Of 107 patients 104 underwent first check cystoscopy, including 90 (87%) who were clear. Of the 90 complete responders 86 underwent 1-year cystoscopy, including 74 (86%) who were recurrence-free. Of the 74 patients 71 underwent 2-year cystoscopy, of whom 66 (93%) remained recurrence-free. The full induction schedule was not completed in 30 patients (28%), including 16 and 14 with minor and major schedule alterations, respectively. There was no difference in recurrence between patients who received a full vs a reduced induction schedule. CONCLUSIONS: This study confirms the excellent oncologic efficacy of sequential bacillus Calmette-Guérin/electromotive drug administration of mitomycin C in cases of high risk, nonmuscle invasive bladder cancer. Tolerability is a challenge but alterations to the 9-week schedule appeared to have a negligible impact on outcomes.

In vitro chemoresponse analysis of cervical cancer patient specimens.

PURPOSE: The objective of this study was to report the results of in vitro chemoresponse analysis of primary, metastatic, and recurrent human cervical cancers. METHODS: There were 557 tumor specimens submitted for testing from August 2006 to June 2010. Single agents tested were cisplatin, carboplatin, paclitaxel, docetaxel, epirubicin, fluorouracil, 4-hydroxy ifosfamide (active metabolite of ifosfamide), SN-38 (active metabolite of irinotecan), topotecan, and vinorelbine. Doublets tested were carboplatin/paclitaxel and cisplatin/topotecan. Tumor response was determined from dose-response curves. Results were scored as responsive, intermediate, or nonresponsive. Chemoresponse was reported as the combined responsive and intermediate results. RESULTS: Three hundred fifty-three (63.4%) of 557 submitted specimens were successfully assayed. Confirmation of histology and tumor status (primary, metastatic, or recurrent) was available for 273 specimens. The chemoresponse of the most active agents in primary cancers (n = 151) was 75% for SN-38, 71% for 4-hydroxy ifosfamide, 62% for topotecan, and 73% for carboplatin/paclitaxel. The chemoresponse of metastatic cancers (n = 66) was 54% for SN-38, 51% for 4-hydroxy ifosfamide, 44% for epirubicin, and 53% for carboplatin/paclitaxel. The chemoresponse for recurrent cancers (n = 56) was 44% for epirubicin, 41% for 4-hydroxy ifosfamide, 39% for vinorelbine, 39% for paclitaxel, 36% for topotecan, 46% for carboplatin/paclitaxel, and 35% for cisplatin/topotecan. The overall chemoresponse was greater in primary cancers (58%) than in recurrent cancers (35%) (P < 0.0001). CONCLUSIONS: In vitro chemoresponse analysis of cervical cancer biospecimens is feasible. Chemoresponse results are variable depending on tumor status. Clinical studies of assay-directed therapy should be developed.

Snapshot of transurethral resection of bladder tumours in the United Kingdom Audit (STUKA).

OBJECTIVES: To determine the quality of transurethral resection of bladder tumour (TURBT) in the UK. To evaluate the utility of a novel 'snapshot' methodology in carrying out national audits. PATIENTS AND METHODS: Every consultant Urologist in the UK was asked to contribute details of their first patient with a new bladder cancer treated with TURBT after midnight of 31st January 2010. Responses were received from 192 consultants. RESULTS: The median (range) time from referral to first Urology appointment was 11 (0-161) days, and the median (range) time from first appointment to TURBT was 27 (1-588) days. In all, 12 (6.3%) patients underwent photodynamic diagnosis-assisted TURBT and 119 patients (61%) received a dose of Mitomycin C after TURBT. The rate of major complications was low, with five incidences (2.6%) of bladder perforation. There was no record of muscle present in resected specimens in 40 cases (20.8%) and resection was considered incomplete in 26 cases (13.5%). In all, 31 patients (16.1%) underwent early re-resection with residual tumour or carcinoma in situ detected in 17 cases, although no tumour was upstaged. Of the 37 patients classified with intermediate-risk non-muscle-invasive bladder cancer (NMIBC), there were nine recurrences (24.3%) at 3 months, and 13 recurrences (35.1%) at 1 year. Newly presenting MIBC managed with currently available treatments has a high mortality rate of 33.3% at 1 year. CONCLUSIONS: The quality of TURBT in the UK is high. Areas for improvement include the timeliness of diagnosis and treatment, and improved care of patients with intermediate-risk NMIBC and MIBC. The 'snapshot' methodology is promising but widening participation is a priority.

Genetic inactivation of AKT1, AKT2, and PDPK1 in human colorectal cancer cells clarifies their roles in tumor growth regulation.

Phosphotidylinositol-3-kinase (PI3K) signaling is altered in the majority of human cancers. To gain insight into the roles of members of this pathway in growth regulation, we inactivated AKT1, AKT2, or PDPK1 genes by targeted homologous recombination in human colon cancer cell lines. Knockout of either AKT1 or AKT2 had minimum effects on cell growth or downstream signaling. In contrast, knockout of both AKT1 and AKT2 resulted in markedly reduced proliferation in vitro when growth factors were limiting and severely affected experimental metastasis in mice. Unexpectedly, AKT1 and AKT2 appeared to regulate growth through FOXO proteins, but not through either GSK3beta or mTOR. In contrast, inactivation of PDPK1 affected GSK3beta and mTOR activation. These findings show that the PI3K signaling pathway is wired differently in human cancer cells than in other cell types or organisms, which has important implications for the design and testing of drugs that target this pathway.

Consistency of in vitro chemoresponse assay results and population clinical response rates among women with endometrial carcinoma.

BACKGROUND: There are a number of equally efficacious chemotherapy options for the treatment of women with endometrial cancer, all of which work in only a subset of those women with this disease. An in vitro assay performed before therapy initiation to identify the drug(s) most likely to be effective for the individual patient would have clinical utility. Such an assay should yield response rates similar to those found in treated patient populations. The purpose of this investigation was to determine whether the patterns of in vitro tumor response rates as determined by ChemoFx are consistent with expected population response rates. METHODS: Nine hundred twenty-three tumor specimens from patients with high-risk early-stage, advanced stage, or recurrent endometrial cancer were sent for testing with the ChemoFx drug response marker from August 2, 2006, to August 31, 2009. Tumors were categorized as responsive (R), intermediately responsive (IR), or nonresponsive to each drug or combination tested. Response rates from clinical trials were identified and compared with the corresponding in vitro response rates. RESULTS: Of the 923 specimens received, 759 (82%) were successfully tested by ChemoFx. Of these, 755 were tested for at least 1 of 5 National Comprehensive Cancer Network-recommended endometrial cancer drugs. The response rates (R+IR) for these drugs were as follows: 66% carboplatin-paclitaxel, 48% carboplatin, 37% cisplatin, 23% doxorubicin, and 36% paclitaxel. Moreover, 20% of tumors were pan-sensitive (R or IR) to all 5 regimens tested, 27% were pan-resistant (nonresponsive), and 53% showed different degrees of response to different drugs. CONCLUSIONS: ChemoFx in vitro response rates were consistent with published population response rates, and the ChemoFx drug response marker may provide clinically useful information to better optimize individual chemotherapy for treatment of women with endometrial cancer.

Long-term Oncological Outcomes from an Early Phase Randomised Controlled Three-arm Trial of Open, Robotic, and Laparoscopic Radical Cystectomy (CORAL).

BACKGROUND: The long-term oncological outcomes of laparoscopic (LRC) and robotic-assisted radical cystectomy (RARC) are still maturing compared with open radical cystectomy (ORC). OBJECTIVE: To evaluate the 5-yr oncological outcomes of patients recruited into the randomised trial of Open, Laparoscopic and Robot Assisted Cystectomy (CORAL) and extracorporeal urinary diversion. DESIGN, SETTING, AND PARTICIPANTS: A review of prospectively maintained database of 60 patients with muscle-invasive bladder cancer (MIBC) or high-risk nonmuscle-invasive bladder cancer (HRNMIBC) who were previously randomised in the CORAL trial to receive ORC, RARC, or LRC. This trial was designed to compare the perioperative and early oncological outcomes of these techniques. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: The outcomes of interest included 5-yr recurrence-free survival (RFS), cancer-specific survival (CSS), and overall survival (OS). Kaplan-Meier curves were used to plot the recurrence and survival data. The curves between RFS, CSS, and OS were compared using the log-rank test. A two-sided p value <0.05 was considered significant. Results were analysed on the basis of intention to treat. RESULTS AND LIMITATIONS: A total of 60 patients with either MIBC (n=38) or HRNMIBC (n=21) were randomised in the CORAL trial to receive ORC, RARC, or LRC. The 5-yr RFS was 60%, 58%, and 71%; 5-yr CSS was 64%, 68%, and 69%; and 5-yr OS was 55%, 65%, and 61% for ORC, RARC, and LRC, respectively. There was no significant difference in RFS, CSS, and OS between the three surgical arms. The principal limitation is the small sample size. CONCLUSIONS: There was no difference in 5-yr RFS, CSS, and OS rates of patients who underwent ORC, RARC, and LRC for management of bladder cancer. Minimally invasive techniques achieved equivalent oncological outcomes to the gold standard of ORC. However, the study was based at a single institution with a small sample size. PATIENT SUMMARY: Patients who agreed to participate in the randomised trial of either open, laparoscopic, or robotic-assisted radical cystectomy for bladder cancer did not have different cancer outcomes at 5yr.

Induction of persistent colitis by a human commensal, enterotoxigenic Bacteroides fragilis, in wild-type C57BL/6 mice.

Enterotoxigenic Bacteroides fragilis (ETBF) causes diarrhea and is implicated in inflammatory bowel diseases and colorectal cancer. The only known ETBF virulence factor is the Bacteroides fragilis toxin (BFT), which induces E-cadherin cleavage, interleukin-8 secretion, and epithelial cell proliferation. A murine model for ETBF has not been characterized. Specific pathogen-free (SPF) C57BL/6J or germfree 129S6/SvEv mice were orally inoculated with wild-type ETBF (WT-ETBF) strains, a nontoxigenic WT strain of B. fragilis (WT-NTBF), WT-NTBF overexpressing bft (rETBF), or WT-NTBF overexpressing a biologically inactive mutated bft (rNTBF). In SPF and germfree mice, ETBF caused colitis but was lethal only in germfree mice. Colonic histopathology demonstrated mucosal thickening with inflammatory cell infiltration, crypt abscesses, and epithelial cell exfoliation, erosion, and ulceration. SPF mice colonized with rETBF mimicked WT-ETBF, whereas rNTBF caused no histopathology. Intestinal epithelial E-cadherin was rapidly cleaved in vivo in WT-ETBF-colonized mice and in vitro in intestinal tissues cultured with purified BFT. ETBF mice colonized for 16 months exhibited persistent colitis. BFT did not directly induce lymphocyte proliferation, dendritic cell stimulation, or Toll-like receptor activation. In conclusion, WT-ETBF induced acute then persistent colitis in SPF mice and rapidly lethal colitis in WT germfree mice. Our data support the hypothesis that chronic colonization with the human commensal ETBF can induce persistent, subclinical colitis in humans.

UK medical students' perceptions, attitudes, and interest toward medical leadership and clinician managers.

BACKGROUND: We aimed to determine UK medical students' perceptions and attitudes and interest toward medical leadership and clinician managers. METHODS: A cross-sectional study was conducted during the academic year 2015-2016. An online questionnaire was distributed to 2,349 final-year students from 10 UK medical schools. Participants were asked to complete a 5-point Likert scale on their current perceptions, attitudes, and interest toward medical leadership and clinician managers. They were also asked to self-rate their leadership competences set by the Medical Leadership Competency Framework and to rate the quality of management and leadership training they received from their medical school. RESULTS: In total, we received 114 complete responses. Only 7.9% of respondents were in agreement (strongly agree or agree) when asked whether they felt they were well informed about what a managerial position in medicine entails. When asked whether clinicians should influence managerial decisions within a clinical setting, 94.7% of respondents were in agreement with the statement. About 85% of respondents were in agreement that it is important for clinicians to have managerial or leadership responsibilities, with 63.2% of students in agreement that they would have liked more management or leadership training during medical school. Over half the respondents rated their management and leadership training they received during medical school as "very poor" or "poor" (54.4%). CONCLUSION: Our study suggests that UK medical students have an appetite for management and leadership training and appreciate its importance but feel that the training they are receiving is poor. This suggests that there is a gap between the demand for management and leadership training and the quality of training supplied by UK medical schools.

Enterotoxigenic bacteroides fragilis: a potential instigator of colitis.

BACKGROUND: Inflammatory bowel disease (IBD) is proposed to result from a dysregulated mucosal immune response to the colonic flora in genetically susceptible individuals. Enterotoxigenic Bacteroides fragilis (ETBF), a molecular subclass of the common human commensal, B. fragilis, has been associated with IBD. This study investigated whether ETBF colonization of mice initiated colitis or modified the clinical course of a colitis agonist, dextran sodium sulfate (DSS). METHODS: Four- and 6-week-old C57BL/6 mice were inoculated with buffer, nontoxigenic B. fragilis (NTBF) strain 9343(pFD340), or ETBF strain 86-5443-2-2 via orogastric tube. A subset of mice received 2% DSS several days pre- or post-inoculation of bacteria. Clinical status was assessed throughout the experiment and severity of colonic inflammation was scored after sacrifice. RESULTS: All mice, including those receiving DSS, were clinically well prior to bacterial inoculation. NTBF and ETBF colonization was similar. Regardless of mouse age or timing of DSS administration, mice who received ETBF+DSS experienced worse colitis reflected by less weight gain, enhanced gross disease, and greater inflammation in their colons (P < 0.05), especially in the cecum. In particular, younger mice had more extensive disease. Mice inoculated only with ETBF also exhibited colitis with more severe inflammation when compared to all other groups (P < 0.05) except the ETBF+DSS group. CONCLUSIONS: ETBF, a colonic commensal, alone stimulates colitis and significantly enhances colonic inflammation in DSS-treated mice. This study suggests that acquisition of ETBF colonization may be a potential factor in initiation and/or exacerbation of colitis.

A Single-centre Early Phase Randomised Controlled Three-arm Trial of Open, Robotic, and Laparoscopic Radical Cystectomy (CORAL).

BACKGROUND: Laparoscopic radical cystectomy (LRC) and robot-assisted radical cystectomy (RARC) are increasingly popular, but high-level evidence for these techniques remains lacking. OBJECTIVE: To compare the outcomes of patients undergoing open radical cystectomy (ORC), RARC, and LRC. DESIGN, SETTING, AND PARTICIPANTS: From March 2009 to July 2012, 164 patients requiring radical cystectomy for muscle-invasive bladder cancer or high-risk non-muscle-invasive bladder cancer were invited to participate, with an aim of recruiting 47 patients into each arm. Overall, 93 were suitable for trial inclusion; 60 (65%) agreed and 33 (35%) declined. INTERVENTION: ORC, RARC, or LRC with extracorporeal urinary diversion. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Primary end points were 30- and 90-d complication rates. Secondary end points were perioperative clinical, pathologic, and oncologic outcomes, and quality of life (QoL). The Fisher exact test and analysis of variance were used for statistical analyses. RESULTS AND LIMITATIONS: The 30-d complication rates (classified by the Clavien-Dindo system) varied significantly between the three arms (ORC: 70%; RARC: 55%; LRC: 26%; p=0.024). ORC complication rates were significantly higher than LRC (p<0.01). The 90-d complication rates did not differ significantly between the three arms (ORC: 70%; RARC: 55%; LRC 32%; p=0.068). Mean operative time was significantly longer in RARC compared with ORC or LRC. ORC resulted in a slower return to oral solids than RARC or LRC. There were no significant differences in QoL measures. Major limitations are the small sample size and potential surgeon bias. CONCLUSIONS: The 30-d complication rates varied by type of surgery and were significantly higher in the ORC arm than the LRC arm. There was no significant difference in 90-d Clavien-graded complication rates between the three arms. PATIENT SUMMARY: We compared patients having open, robotic, or laparoscopic bladder removal surgery for bladder cancer and found no difference in Clavien-graded complication rates at 90 d.

Pain control in a randomized, controlled, clinical trial comparing moist exposed burn ointment and conventional methods in patients with partial-thickness burns.

Conventional management of partial-thickness burn wounds includes the use of paraffin gauze dressing, frequently with topical silver-based antibacterial creams. Some creams form an overlying slough that renders wound assessment difficult and are painful upon application. An alternative to conventional management, moist exposed burn ointment (MEBO), has been proposed as a topical agent that may accelerate wound healing and have antibacterial and analgesic properties. One hundred fifteen patients with partial-thickness burns were randomly assigned to conventional (n = 58) or MEBO treatment (n = 57). A verbal numerical rating score of pain was made in the morning, after burn dressing, and some 8 hours later. Patient pain profiles were summarized by locally weighted regression smoothing technique curves and the difference between treatments estimated using multilevel regression techniques. Mean verbal numerical rating scale pain levels (cm) in week 1 for all patients were highest at 3.2 for the after dressing assessment, lowest in the evening at 2.6, and intermediate in the morning at 3.0. This pattern continued at similar levels in week 2 and then declined by a mean of 0.5 in all groups in week 3. There was little evidence to suggest a difference in pain levels by treatment group with the exception of the postdressing pain levels in the first week when those receiving MEBO had a mean level of 0.7 cm (95% confidence interval, 0.2 to 1.1) lower than those on conventional therapy. MEBO appeared to bring greater pain relief for the postdressing assessment during the first week after burns. This initial relief, together with comparable pain levels experienced on other occasions, indicates that MEBO could be an alternative to conventional burns management.

Diagnosis and management of intradiverticular bladder tumours.

Intradiverticular bladder tumours (IDBT) account for approximately 1% of all urinary bladder tumours. The risk of developing a tumour within a bladder diverticulum is considered to be greater than in the main bladder, possibly owing to prolonged contact of potential carcinogens with the mucosal lining from urinary stasis. Patients with these tumours most commonly present with visible haematuria. Diagnostic tests include urine cytology, cystoscopy, ultrasonography, CT, MRI, and biopsy. Lack of muscle in the diverticula increases the risk of bladder perforation during biopsy and makes pathological staging difficult as there is no T2 stage; instead, data suggest that any invasion beyond the lamina propria should be described as T3. IDBT can be managed by transurethral resection and adjuvant intravesical therapy, diverticulectomy, or cystectomy (partial or radical), as outlined by the only guidelines to specifically address the management of IDBT, which were published by the Cancer Committee of the French Association of Urology (CCAFU) in 2012. The prognosis of patients with intradiverticular bladder tumours has always been perceived to be worse than those with intravesical tumours; however, the only study of 5-year survival rates for patients with IDBT suggests that prognosis might be comparable for these conditions.

BCG immunotherapy for bladder cancer--the effects of substrain differences.

Genetic mutations have been progressively introduced to BCG by repeated serial passage over many decades of its culture and global dissemination. Thus, marked differences exist in the phenotype, antigenicity, reactogenicity, and clinical characteristics of the numerous substrains of BCG currently in use for bladder cancer immunotherapy. These differences influence proposed mycobacterial antitumour mechanisms and toxicity, potentially resulting in variations in clinical efficacy and adverse effects. However, although there is evidence of substrain-related differences in the clinical efficacy of BCG as a tuberculosis vaccine, evidence of an effect on bladder cancer immunotherapy remains elusive, owing to the lack of appropriately powered head-to-head comparative clinical trials, the nonstandardization of BCG manufacture, and variation in treatment protocols--possibly itself a response to underlying substrain differences. Advances in our understanding of mycobacterial genetics, structure and function, and host-pathogen interactions might explain differences in clinical practice and outcomes. These advances are guiding the identification of biomarkers for reactogenicity and efficacy, and the rational design of immunotherapeutic strategies to eliminate the use of live bacilli for bladder cancer therapy.

The transmembrane tyrosines Y56, Y91 and Y167 play important roles in determining the affinity and transport rate of the rabbit proton-coupled peptide transporter PepT1.

The mammalian proton-coupled peptide transporter PepT1 is widely accepted as the major route of uptake for dietary nitrogen, as well as being responsible for the oral absorption of a number of classes of drugs, including beta-lactam antibiotics and angiotensin-converting enzyme (ACE) inhibitors. Using site-directed mutagenesis and zero-trans transport assays, we investigated the role of conserved tyrosines in the transmembrane domains (TMDs) of rabbit PepT1 as predicted by hydropathy plots. All the individual TMD tyrosines were substituted with phenylalanine and shown to retain the ability to traffic to the plasma membrane of Xenopus laevis oocytes. These single substitutions of TMD tyrosines by phenylalanine residues did not affect the proton dependence of peptide uptake, with all retaining wild-type PepT1-like pH dependence. Individual mutations of four of the nine TMD residue tyrosines (Y64, Y287, Y345 and Y587) were without measurable effect on PepT1 function, whereas the other five (Y12, Y56, Y91, Y167 and Y345) were shown to result in altered transport function compared to the wild-type PepT1. Intriguingly, the affinity of Y56F-PepT1 was found to be dramatically increased (approximately 100-fold) in comparison to that of the wild-type rabbit PepT1. Y91 mutations also affected the substrate affinity of the transporter, which increased in line with the hydrophilicity of the substituted amino acid (F>Y>Q>R). Y167 was demonstrated to play a pivotal role in rabbit PepT1 function since Y167F, Y167R and Y167Q demonstrated very little transport function. These results are discussed with regard to a proposed mechanism for PepT1 substrate binding.

A multidimensional analysis of genes mutated in breast and colorectal cancers.

A recent study of a large number of genes in a panel of breast and colorectal cancers identified somatic mutations in 1149 genes. To identify potential biological processes affected by these genes, we examined their putative roles based on sequence similarity, membership in known functional groups and pathways, and predicted interactions with other proteins. These analyses identified functional groups and pathways that were enriched for mutated genes in both tumor types. Additionally, the results pointed to differences in molecular mechanisms that underlie breast and colorectal cancers, including various intracellular signaling and metabolic pathways. These studies provide a multidimensional framework to guide further research and help identify cellular processes critical for malignant progression and therapeutic intervention.