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Infection reduces survival in cardiovascular implantable electronic device (CIED) recipients. However, the clinical predictors of short- and long-term mortality in patients with CIED infection are not well understood. We retrospectively reviewed all patients with CIED infection who were admitted to Mayo Clinic from January 1991 to December 2008. Survival data were obtained from the medical records and the United Sates Social Security Index. The purported risk factors for short-term (30-day) and long-term (>30-day) mortality were analyzed using univariate and multivariate models. Overall, 415 cases of CIED infection were identified during the study period. The mean follow-up duration for the 243 patients who were alive at the last follow-up visit was 6.9 years. In a multivariate model, heart failure (odds ratio 9.31, 95% confidence interval 2.08 to 41.67), corticosteroid therapy (odds ratio 4.04, 95% confidence interval 1.40 to 11.60), and presentation with CIED-related infective endocarditis (odds ratio 5.60, 95% confidence interval 2.25 to 13.92) were associated with increased short-term mortality. The factors associated with long-term mortality in the multivariate model included patient age (hazard ratio 1.20, 95% confidence interval 1.06 to 1.36), heart failure (hazard ratio 2.01, 95% confidence interval 1.42 to 2.86), metastatic malignancy (hazard ratio 5.99, 95% confidence interval 1.67 to 21.53), corticosteroid therapy (hazard ratio 1.97, 95% confidence interval 1.22 to 3.18), renal failure (hazard ratio 1.94, 95% confidence interval 1.37 to 2.74), and CIED-related infective endocarditis (hazard ratio 1.68, 95% confidence interval 1.17 to 2.41). In conclusion, these data suggest that the development of CIED-related infective endocarditis and the presence of co-morbid conditions are associated with increased short- and long-term mortality in patients with CIED infection., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Background: There are no prospective data regarding the risk of prosthetic joint infection following routine gastrointestinal endoscopic procedures. We wanted to determine the risk of prosthetic hip or knee infection following gastrointestinal endoscopic procedures in patients with joint arthroplasty., Methods: We conducted a prospective, single-center, case-control study at a single, tertiary-care referral center. Cases were defined as adult patients hospitalized for prosthetic joint infection of the hip or knee between December 1, 2001 and May 31, 2006. Controls were adult patients with hip or knee arthroplasties but without a diagnosis of joint infection, hospitalized during the same time period at the same orthopedic hospital. The main outcome measure was the odds ratio (OR) of prosthetic joint infection after gastrointestinal endoscopic procedures performed within 2 years before admission., Results: 339 cases and 339 controls were included in the study. Of these, 70 cases (21%) cases and 82 controls (24%) had undergone a gastrointestinal endoscopic procedure in the preceding 2 years. Among gastrointestinal procedures that were assessed, esophago-gastro-duodenoscopy (EGD) with biopsy was associated with an increased risk of prosthetic joint infection (OR = 3, 95% CI: 1.1-7). In a multivariable analysis adjusting for sex, age, joint age, immunosuppression, BMI, presence of wound drain, prior arthroplasty, malignancy, ASA score, and prothrombin time, the OR for infection after EGD with biopsy was 4 (95% CI: 1.5-10)., Interpretation: EGD with biopsy was associated with an increased risk of prosthetic joint infection in patients with hip or knee arthroplasties. This association will need to be confirmed in other epidemiological studies and adequately powered prospective clinical trials prior to recommending antibiotic prophylaxis in these patients.

These guidelines are intended for use by infectious disease specialists, orthopedists, and other healthcare professionals who care for patients with prosthetic joint infection (PJI). They include evidence-based and opinion-based recommendations for the diagnosis and management of patients with PJI treated with debridement and retention of the prosthesis, resection arthroplasty with or without subsequent staged reimplantation, 1-stage reimplantation, and amputation.

These guidelines are intended for use by infectious disease specialists, orthopedists, and other healthcare professionals who care for patients with prosthetic joint infection (PJI). They include evidence-based and opinion-based recommendations for the diagnosis and management of patients with PJI treated with debridement and retention of the prosthesis, resection arthroplasty with or without subsequent staged reimplantation, 1-stage reimplantation, and amputation.

Background: The purpose of this phase Ib clinical trial was to determine the maximum tolerated dose (MTD) of PR-104 a bioreductive pre-prodrug given in combination with gemcitabine or docetaxel in patients with advanced solid tumours., Methods: PR-104 was administered as a one-hour intravenous infusion combined with docetaxel 60 to 75 mg/m2 on day one given with or without granulocyte colony stimulating factor (G-CSF) on day two or administrated with gemcitabine 800 mg/m2 on days one and eight, of a 21-day treatment cycle. Patients were assigned to one of ten PR-104 dose-levels ranging from 140 to 1100 mg/m2 and to one of four combination groups. Pharmacokinetic studies were scheduled for cycle one day one and 18F fluoromisonidazole (FMISO) positron emission tomography hypoxia imaging at baseline and after two treatment cycles., Results: Forty two patients (23 females and 19 males) were enrolled with ages ranging from 27 to 85 years and a wide range of advanced solid tumours. The MTD of PR-104 was 140 mg/m2 when combined with gemcitabine, 200 mg/m2 when combined with docetaxel 60 mg/m2, 770 mg/m2 when combined with docetaxel 60 mg/m2 plus G-CSF and ≥770 mg/m2 when combined with docetaxel 75 mg/m2 plus G-CSF. Dose-limiting toxicity (DLT) across all four combination settings included thrombocytopenia, neutropenic fever and fatigue. Other common grade three or four toxicities included neutropenia, anaemia and leukopenia. Four patients had partial tumour response. Eleven of 17 patients undergoing FMISO scans showed tumour hypoxia at baseline. Plasma pharmacokinetics of PR-104, its metabolites (alcohol PR-104A, glucuronide PR-104G, hydroxylamine PR-104H, amine PR-104M and semi-mustard PR-104S1), docetaxel and gemcitabine were similar to that of their single agents., Conclusions: Combination of PR-104 with docetaxel or gemcitabine caused dose-limiting and severe myelotoxicity, but prophylactic G-CSF allowed PR-104 dose escalation with docetaxel. Dose-limiting thrombocytopenia prohibited further evaluation of the PR104-gemcitabine combination. A recommended dose was identified for phase II trials of PR-104 of 770 mg/m2 combined with docetaxel 60 to 75 mg/m2 both given on day one of a 21-day treatment cycle supported by prophylactic G-CSF (NCT00459836).

Staphylococci account for the bulk of cardiovascular implantable electronic device (CIED) infections. However, a detailed analysis of clinical features and outcomes of CIED infections due to staphylococcal species has not been published. We retrospectively reviewed all cases of CIED infection seen at the Mayo Clinic from 1991 through 2008. Differences in device and host factors, clinical features, and patient outcomes were compared between cases of early and late Staphylococcus aureus and coagulase-negative staphylococci (CoNS) CIED infections. Of 280 cases of staphylococcal CIED infections, 43.9% were due to S. aureus and 56.0% were due to CoNS. Staphylococcus aureus CIED infection cases more frequently involved initially implanted devices. Late S. aureus CIED infection cases compared to late CoNS cases were associated with corticosteroid therapy, hemodialysis, implanted catheters, prosthetic valves, and remote sources of bacteremia. Cases of S. aureus endovascular infections had longer duration of bacteremia (56.0% vs 20.3% ≥3 days), longer hospitalization (37.4% vs 15.2% >20 days), and increased mortality (25.2% vs 9.5%) compared to cases of CoNS endovascular infections (p <0.001 for all comparisons). Overall, CoNS CIED infections compared to S. aureus were associated with a history of multiple device revisions and a higher number of total and abandoned leads at presentation (p <0.001 for all comparisons). In conclusion, CIED infections due to S. aureus and CoNS have distinct clinical features and outcomes., (Copyright © 2012 Elsevier Inc. All rights reserved.)

Background: The American Heart Association published updated guidelines for infective endocarditis (IE) prevention in 2007 that markedly restricted the use of antibiotic prophylaxis in certain at-risk patients undergoing dental and other invasive procedures. The incidence of IE caused by viridans group streptococci (VGS) in the United States after publication of the 2007 American Heart Association guidelines has not been reported., Methods and Results: We performed a population-based review of all definite or possible cases of VGS-IE using the Rochester Epidemiology Project of Olmsted County, Minnesota. Patient demographics and microbiological data were collected for all VGS-IE cases diagnosed from January 1, 1999, through December 31, 2010. We also examined the Nationwide Inpatient Sample hospital discharge database to determine the number of VGS-IE cases included between 1999 and 2009. We identified 22 cases with VGS-IE in Olmsted County over the 12-year study period. Rates of incidence (per 100 000 person-years) during time intervals of 1999-2002, 2003-2006, and 2007-2010 were 3.19 (95% confidence interval, 1.20-5.17), 2.48 (95% confidence interval, 0.85-4.10), and 0.77 (95% confidence interval, 0.00-1.64), respectively (P=0.061 from Poisson regression). The number of hospital discharges with a VGS-IE diagnosis in the Nationwide Inpatient Sample database during 1999-2002, 2003-2006, and 2007-2009 ranged between 15 318 to 15 938, 16 214 to 17 433, and 14 728 to 15 479, respectively., Conclusions: On the basis of data complete through 2010, there has been no perceivable increase in the incidence of VGS-IE in Olmsted County, Minnesota, since the publication of the 2007 American Heart Association endocarditis prevention guidelines.

Objectives: Since 2009 the National Health Service (NHS) has been collecting patient-reported outcome measures (PROMs) following varicose vein interventions. The objective of this manuscript was to interrogate the one-year PROMs data with respect to varicose vein intervention and to discuss its potential impact on the provision of service., Methods: We interrogated the one-year PROMs data with respect to potential impact on the provision of service., Results: In total, 37,521 varicose vein operations were performed during the study period (1 April 2009-30 April 2010). A total of 15,808 preoperative questionnaires were completed and returned and 12,509 were linked to Hospital Episode Statistics episodes. A total of 8127 postoperative questionnaires were completed and linked to the preoperative questionnaires. For the EuroQuol (EQ) 5D questionnaire average preoperative score across the completed data-set was 0.773. The postoperative health gain was 0.094. Fifty-three percent of patients had improved postoperative scores, 33% reported no change, while 14% reported a reduction in their postoperative EQ-5D score. Pain/discomfort was the only domain where patients reported any negative symptoms; 72% (5390) reported pain/discomfort preoperatively and 37% (2804) postoperatively. In total, 62.6% (4685) reported no pain/discomfort following surgery A total of 7167 complete, linked and eligible data-sets were observed for the Aberdeen Varicose Vein Questionnaire (AVVQ). The average preoperative score was 18.75. The average postoperative score was 10.76. This represented a reduction in symptom scores of one-half following intervention. The lowest improvements were witnessed in patients with the lowest preoperative scores (least severe symptoms). Additional postoperative questions highlighted the improvements conferred from varicose vein surgery with 90.3% of patients reporting an improvement in their problems from varicose veins following surgery and 85% describing their operative results as excellent, very good or good., Conclusion: These data have shown variable improvements following venous interventions. PROMs are likely to have significant implications for health care in the NHS on a number of levels including provision of funding and future planning of services.

A link between oral health and cardiovascular disease has been proposed for more than a century. Recently, concern about possible links between periodontal disease (PD) and atherosclerotic vascular disease (ASVD) has intensified and is driving an active field of investigation into possible association and causality. The 2 disorders share several common risk factors, including cigarette smoking, age, and diabetes mellitus. Patients and providers are increasingly presented with claims that PD treatment strategies offer ASVD protection; these claims are often endorsed by professional and industrial stakeholders. The focus of this review is to assess whether available data support an independent association between ASVD and PD and whether PD treatment might modify ASVD risks or outcomes. It also presents mechanistic details of both PD and ASVD relevant to this topic. The correlation of PD with ASVD outcomes and surrogate markers is discussed, as well as the correlation of response to PD therapy with ASVD event rates. Methodological issues that complicate studies of this association are outlined, with an emphasis on the terms and metrics that would be applicable in future studies. Observational studies to date support an association between PD and ASVD independent of known confounders. They do not, however, support a causative relationship. Although periodontal interventions result in a reduction in systemic inflammation and endothelial dysfunction in short-term studies, there is no evidence that they prevent ASVD or modify its outcomes.

A novel murine enzyme, ADP-dependent glucokinase (ADPGK), has been shown to catalyse glucose phosphorylation using ADP as phosphoryl donor. The ancestral ADPGK gene appears to have been laterally transferred from Archaea early in metazoan evolution, but its biological role has not been established. Here, we undertake an initial investigation of the functional properties of human ADPGK in human tumour cell lines and specifically test the hypothesis that ADPGK might prime glycolysis using ADP under stress conditions such as hypoxia. Recombinant human ADPGK was confirmed to catalyse ADP-dependent glucose phosphorylation in vitro, with an apparent K (M) for glucose of 0.29 mM. Expression databases and western blotting of surgical samples demonstrated high expression in many human tissues, including tumours. Unlike hexokinase-2 (HK2), RNAi studies with exon arrays showed that ADPGK is not a transcriptional target of hypoxia inducible factor-1. Consistent with this, ADPGK protein was not upregulated by hypoxia or anoxia. Surprisingly, stable fivefold overexpression of ADPGK in H460 or HCT116 cells had no apparent effect on proliferation or glycolysis, and did not rescue clonogenicity or glycolysis when HK2 was suppressed by siRNA. Furthermore, suppression of ADPGK by siRNA did not cause detectable inhibition of glycolysis or cell killing by anoxia, although it did induce a statistically significant decrease in plating efficiency of H460 cells under aerobic conditions. Thus, human ADPGK catalyses ADP-dependent phosphorylation of glucose in vitro, but despite its high expression in human tumour cell lines it appears not to make a quantifiable contribution to glycolysis under the conditions evaluated.

The Coronary Artery Disease in gENeral practiCE (CADENCE) study examined chronic stable angina (CSA). This further analysis examined atherosclerotic risk factors, symptomatic status, clinical management, and quality of life in patients with CSA with and without peripheral arterial disease (PAD). The CADENCE study involved 207 Australian general practitioners (GPs) recruiting 10 to 15 consecutively presenting patients with CSA (n = 2031). General practitioners completed a 2-page case report form, detailing demographic data, cardiovascular status, risk factors, and GP perception of control. Patients completed the Seattle Angina Questionnaire. Patients with coexisting CSA and PAD (17%) were more likely to be older and had more comorbidities than patients with CSA without coexisting PAD. Patients with peripheral arterial disease had a longer history of heart disease and were more likely to experience angina on a weekly basis. Patients with peripheral arterial disease had poorer quality-of-life indices.

Purpose: Benzotriazine-N-oxide bioreductive prodrugs such as tirapazamine and its improved analogue CEN-209 (SN30000) have potential for exploiting hypoxia in tumors. Here, we test the hypothesis that the 2-nitroimidazole EF5, in clinical development for both immunohistochemical and positron emission tomography imaging of hypoxia, can detect not only hypoxia but also the one-electron reductases required for activation of these hypoxia-targeted prodrugs., Experimental Design: Aerobic and hypoxic covalent binding of [(14)C]-EF5 was determined in human tumor cell lines, including lines with overexpression of NADPH:cytochrome P450 oxidoreductase (CYPOR), and reductive metabolism of tirapazamine and CEN-209 by mass spectrometry. DNA damage response was measured by γH2AX formation. Bioreductive metabolism was modulated in HCT116 tumor xenografts by overexpression of CYPOR and breathing of hyperbaric oxygen or 10% oxygen., Results: Overexpression of CYPOR induced similar 2- to 4-fold increases in EF5 binding and metabolic reduction of tirapazamine and CEN-209 in SiHa and HCT116 cell lines, and similar enhancement of γH2AX formation. EF5 binding and metabolic reduction of the prodrugs were highly correlated in a panel of 14 hypoxic tumor cell lines. In HCT116 xenografts, CYPOR overexpression also significantly increased EF5 binding and CEN-209 reduction, and modification of tumor hypoxia caused similar changes to the bioreductive activation of both agents, resulting in a strong correlation between EF5 binding and CEN209-induced DNA damage (R(2) = 0.68, P < 0.0001) at the individual tumor level., Conclusions: EF5 binding is a promising stratification biomarker for benzotriazine-N-oxide bioreductive prodrugs because of its potential for interrogating reductase activity as well as hypoxia in individual tumors.

CEN-209 (SN30000) is a second-generation benzotriazine di-N-oxide currently in advanced preclinical development as a hypoxia-activated prodrug (HAP). Herein we describe the DNA repair-, hypoxia- and one-electron reductase-dependence of CEN-209 cytotoxicity. We deployed mutant CHO cell lines to generate DNA repair profiles for CEN-209, and compared the profiles with those for other HAPs. Hypoxic selectivity of CEN-209 was significantly greater than PR-104A and the nitro-chloromethylbenzindoline (nCBI/SN29428) and comparable to tirapazamine and TH-302. CEN-209 was selective for homologous recombination (HR) repair-deficient cells (Rad51d⁻/⁻), but less so than nitrogen mustard prodrugs TH-302 and PR-104A. Further, DNA repair profiles for CEN-209 differed under oxic and hypoxic conditions, with oxic cytotoxicity more dependent on HR. This feature was conserved across all three members of the benzotriazine di-N-oxide class examined (tirapazamine, CEN-209 and CEN-309/SN29751). Enhancing one-electron reduction of CEN-209 by forced expression of a soluble form of NADPH:cytochrome P450 oxidoreductase (sPOR) increased CEN-209 cytotoxicity more markedly under oxic than hypoxic conditions. Comparison of oxygen consumption, H₂O₂ production and metabolism of CEN-209 to the corresponding 1-oxide and nor-oxide reduced metabolites suggested that enhanced oxic cytotoxicity in cells with high one-electron reductase activity is due to futile redox cycling. This study supports the hypothesis that both oxic and hypoxic cell killing by CEN-209 is mechanistically analogous to tirapazamine and is dependent on oxidative DNA damage repaired via multiple pathways. However, HAPs that generate DNA interstrand cross-links, such as TH-302 and PR-104, may be more suitable than benzotriazine di-N-oxides for exploiting reported HR repair defects in hypoxic tumour cells., (Copyright © 2011. Published by Elsevier Inc.)

Quaternary salt analogues based on the DNA minor groove binder and adenine N3 alkylating agent 5-amino-1-(chloromethyl)-1,2-dihydro-3H-benz[e]indole (aminoCBI) show remarkable effects on the body weight of mice (a long-term failure to gain weight relative to matched controls with no loss of appetite or perceptible deterioration in health) following administration of a single (non-toxic) dose between about 0.5-5 μmol/kg. The nature of the quaternizing group was not important, but a related hydroxyCBI analogue was much less effective. Compounds where the chloro group was replaced by a hydrogen or hydroxy group (thus abrogating DNA alkylating capability) showed no weight control activity. It is speculated, based on other studies, that the marked long-term weight control effect is due to inhibition of bile flow into the intestine and reduced absorption of triglycerides, together with accelerated cell death in spleen and white adipose tissues due to drug accumulation there. This class of compound may serve as interesting tools for further study of these phenomena., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

Heterocyclic N-oxides are an interesting class of antitumor agents that selectively kill the hypoxic cells found in solid tumors. The hypoxia-selective activity of the lead compound in this class, tirapazamine, stems from its ability to undergo intracellular one-electron reduction to an oxygen-sensitive drug radical intermediate. In the presence of molecular oxygen, the radical intermediate is back-oxidized to the parent molecule. Under hypoxic conditions, the extended lifetime of the drug radical intermediate enables its conversion to a highly cytotoxic DNA-damaging intermediate via a "deoxygenative" mechanism involving the loss of oxygen from one of its N-oxide groups. The natural product myxin is a phenazine di-N-oxide that displays potent antibiotic activity against a variety of organisms under aerobic conditions. In light of the current view of heterocyclic N-oxides as agents that selectively operate under hypoxic conditions, it is striking that myxin was identified from Sorangium extracts based upon its antibiotic properties under aerobic conditions. Therefore, we set out to examine the molecular mechanisms underlying the biological activity of myxin. We find that myxin causes bioreductively activated, radical-mediated DNA strand cleavage under both aerobic and anaerobic conditions. Our evidence indicates that strand cleavage occurs via a deoxygenative metabolism. We show that myxin displays potent cytotoxicity against the human colorectal cancer cell line HCT-116 under both aerobic and anaerobic conditions that is comparable to the cell-killing properties of tirapazamine under anaerobic conditions. This work sheds light on the processes by which the naturally occurring aromatic N-oxide myxin gains its potent antibiotic properties under aerobic conditions. Furthermore, these studies highlight the general potential for aromatic N-oxides to undergo highly cytotoxic deoxygenative metabolism following enzymatic one-electron reduction under aerobic conditions.

The clinical agent PR-104 is converted systemically to PR-104A, a nitrogen mustard prodrug designed to target tumor hypoxia. Reductive activation of PR-104A is initiated by one-electron oxidoreductases in a process reversed by oxygen. The identity of these oxidoreductases is unknown, with the exception of cytochrome P450 reductase (POR). To identify other hypoxia-selective PR-104A reductases, nine candidate oxidoreductases were expressed in HCT116 cells. Increased PR-104A-cytotoxicity was observed in cells expressing methionine synthase reductase (MTRR), novel diflavin oxidoreductase 1 (NDOR1), and inducible nitric-oxide synthase (NOS2A), in addition to POR. Plasmid-based expression of these diflavin oxidoreductases also enhanced bioreductive metabolism of PR-104A in an anoxia-specific manner. Diflavin oxidoreductase-dependent PR-104A metabolism was suppressed >90% by pan-flavoenzyme inhibition with diphenyliodonium chloride. Antibodies were used to quantify endogenous POR, MTRR, NDOR1, and NOS2A expression in 23 human tumor cell lines; however, only POR protein was detectable and its expression correlated with anoxic PR-104A reduction (r(2) = 0.712). An anti-POR monoclonal antibody was used to probe expression using human tissue microarrays; 13 of 19 cancer types expressed detectable POR with 21% of cores (185 of 874) staining positive; this heterogeneity suggests that POR is a useful biomarker for PR-104A activation. Immunostaining for carbonic anhydrase 9 (CAIX), reportedly an endogenous marker of hypoxia, revealed only moderate coexpression (9.6%) of both CAIX and POR across a subset of five cancer types.

Background: Cardiovascular implantable electronic device (CIED) infections are associated with increased mortality. However, detailed analyses of the impact of device removal on mortality have been limited., Objective: This study sought to evaluate the impact of timing device removal on mortality in patients with CIED infections., Methods: We retrospectively reviewed all cases of CIED infections seen at Mayo Clinic Rochester between 1991 and 2008. The impact of device removal on 30-day and 1-year mortality was evaluated using Cox proportional hazards models., Results: Of 416 patients with CIED infection, 23 (5.5%) died by 30 days and 61 (14.6%) died by 1 year. Forty-four (12.0%) developed complications related to device removal, and 3 (0.8%) died. Complete procedural success was achieved in 341 (81.9%) and clinical success in 391 (93.9%) cases. In multivariate analysis, antimicrobial therapy without device removal was associated with a 7-fold increase in 30-day mortality (hazard ratio [HR] 6.97, 95% confidence interval [CI] 1.36 to 35.60). Although device removal complications were associated with increased mortality at 30 days (HR 4.33, 95% CI 1.47 to 12.70) and at 1 year (HR 3.77, 95% CI 1.88 to 7.55), immediate device removal, when compared to delay in device removal in favor of initial conservative therapy with antimicrobials alone, and no device removal, was associated with a 3-fold decrease in 1-year mortality (HR 0.35, 95% CI 0.16 to 0.75)., Conclusion: Although device removal resulted in fatal complications in a few patients, the mortality associated with a delay in device removal was significantly higher. Therefore, early and complete device removal was associated with improved outcomes., (Copyright © 2011 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Background: The phosphate ester PR-104 is rapidly converted in vivo to the alcohol PR-104A, a nitrogen mustard prodrug that is metabolised to hydroxylamine (PR-104H) and amine (PR-104M) DNA crosslinking agents by one-electron reductases in hypoxic cells and by aldo-keto reductase 1C3 independently of oxygen. In a previous phase I study using a q 3 week schedule of PR-104, the maximum tolerated dose (MTD) was 1100 mg/m2 and fatigue, neutropenic fever and infection were dose-limiting. The primary objective of the current study was to determine the dose-limiting toxicity (DLT) and MTD of weekly PR-104., Methods: Patients with advanced solid tumours received PR-104 as a 1-hour intravenous infusion on days 1, 8 and 15 every 28 days with assessment of pharmacokinetics on cycle 1 day 1. Twenty-six patients (pts) were enrolled (16 male/10 female; median age 58 yrs, range 30 to 70 yrs) who had received a median of two prior chemotherapy regimens (range, 0 to 3) for melanoma (8 pts), colorectal or anal cancer (3 pts), NSCLC (3 pts), sarcoma (3 pts), glioblastoma (2 pts), salivary gland tumours (2 pts) or other solid tumours (5 pts). PR-104 was administered at 135 mg/m2 (3 pts), 270 mg/m2 (6 pts), 540 mg/m2 (6 pts), 675 mg/m2 (7 pts) and 900 mg/m2 (4 pts) for a median of two treatment cycles (range, 1 to 7 cycles) and five infusions (range, 1 to 18) per patient., Results: Dose-limiting toxicities (DLTs) during cycle one included grade four thrombocytopenia at 540 mg/m2 (1 of 6 pts) and grade four thrombocytopenia and neutropenia at 900 mg/m2 (2 of 4 pts). At an intermediate dose of 675 mg/m2, there were no DLTs among a total of seven patients given 12 treatment cycles but all experienced moderate to severe (grade 2 to 4) haematological toxicity. Thrombocytopenia was delayed in its onset and nadir, and its recovery was protracted and incomplete in many patients. There were no complete or partial tumour responses. PR-104-induced thrombocytopenia and neutropenia correlated with plasma AUC of PR-104, PR-104A and an oxidative semi-mustard metabolite (PR-104S1), but no more strongly than with PR-104 dose-level. There was no significant correlation between plasma AUC for the reduced metabolites and myelotoxicity., Conclusions: Thrombocytopenia, and to a lesser extent neutropenia, was the DLT of weekly PR-104. The MTD was 675 mg/m2/week. PR-104 given weekly may be a suitable protocol for further clinical evaluation as a short course of treatment with fractionated radiotherapy or haematopoietic stem cell support, as its duration of dosing is restricted by delayed-onset and protracted thrombocytopenia.

Background: PR-104 is rapidly hydrolyzed to PR-104A in vivo, which is activated by reduction to the corresponding 5-hydroxylamine (PR-104H) and amine (PR-104M) to produce DNA interstrand cross-links. PR-104 activation can occur via hypoxia-dependent reductases and also independently of hypoxia by aldo-keto reductase (AKR) 1C3., Procedures: PR-104A was tested against the PPTP in vitro panel (10 nM to 100 µM), and PR-104 in vivo using a weekly × 6 schedule at its maximum tolerated dose (MTD) of 550 mg/kg. Subsequently PR-104 was tested at 270 and 110 mg/kg. Pharmacokinetics for PR-104 and its metabolites were determined, as were levels of AKR1C3 RNA and protein in xenografts., Results: In vitro, the leukemia models were most sensitive to PR-104A. In vivo, PR-104 induced objective responses at its MTD in 21/34 solid tumor models and maintained complete responses against 7/7 acute lymphoblastic leukemia (ALL) models. At 270 mg/kg and lower dose levels, PR-104 did not induce solid tumor regressions, suggesting a steep dose-response relationship. Pharmacokinetic analysis suggests higher systemic exposures to PR-104A and its metabolites in mice compared to those achievable in patients. Levels of AKR1C3 protein did not correlate with tumor responsiveness., Conclusions: As monotherapy, PR-104 demonstrated a high level of activity against both solid tumor and ALL models at its MTD, but the activity was almost completely lost at half the MTD dose for solid tumors. Pharmacokinetic data at the PR-104 MTD from human trials suggest that PR-104 metabolites may not reach the plasma exposures in children that were associated with high-level preclinical activity., (Copyright © 2010 Wiley-Liss, Inc.)

A series of cobalt complexes of the potent DNA minor groove alkylator 1-(chloromethyl)-3-(5,6,7-trimethoxyindol-2-ylcarbonyl)-2,3-dihydro-1H-pyrrolo[3,2-f]quinolin-5-ol (seco-6-azaCBI-TMI) were prepared from a series of N-substituted cyclen ligands. The final N-substituted complexes carried formal overall charges ranging from +2 to -2 and showed limited improvements in solubility. They showed similar stabilities to that of the complex with the unsubstituted cyclen ligand, and large but variable attenuation of the cytotoxicity of the free alkylator (2-30-fold), compared to 150-fold for the unsubstituted ligand. However, they had oxic/hypoxic ratios (2-22-fold) comparable to that of the unsubstituted cyclen complex (5)., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

A series of 3-substituted (5-nitro-2,3-dihydro-1H-benzo[e]indol-1-yl)methyl sulfonate (nitroCBI) prodrugs containing sulfonate leaving groups undergo hypoxia-selective metabolism to form potent DNA minor groove alkylating agents. They were evaluated (along with chloride leaving group analogs for comparison) for their cytotoxicity against cultures of SKOV3 and HT29 human tumor cell lines under both aerobic and hypoxic conditions. Sulfonates with neutral side chains (e.g., 5,6,7-trimethoxyindole; TMI) show consistently higher hypoxic cytotoxicity ratios (HCRs) (34-246) than the corresponding chloro analogs (2.8-3.1) in SKOV3 cells, but these trends do not hold for compounds with cationic or polar neutral side chains., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

Aims: The infection rates of implantable cardioverter-defibrillators systems (ICDs) are higher than that of permanent pacemaker. Risk factors associated with ICD infection have not been characterized and are the subject of the current investigation., Methods: All patients who had an ICD implanted at Mayo Clinic Rochester between 1991 and 2008 were retrospectively reviewed. Each case of ICD infection was matched with two non-infected controls. Cases of ICD infection were further stratified by early- (≤ 6 months) versus late-onset (>6 months) infection. Multivariable analysis was performed to identify significant risk factors for ICD infection., Results: Sixty-eight patients with ICD infection and 136 matched controls met the inclusion criteria. Thirty-five cases presented with early-onset infection and 33 had late-onset device infection. Staphylococcal species were the most common pathogens in both groups of patients. Patients with early-onset infection were more likely to present with generator pocket infection (p = 0.02). Patients with multiple comorbid conditions (high Charlson index) tended to have longer hospital stay during implantation admission (p = 0.009). In a multivariable logistic regression model, the presence of epicardial leads (odds ratio (OR) = 9.7, p = 0.03) and postoperative complications at the generator pocket (OR = 27.2, p < 0.001) were significant risk factors for early-onset ICD infection, whereas longer duration of hospitalization at the time of implantation (2 days versus 1 day: OR = 33.1, p < 0.001; ≥ 3 days versus 1 day: OR = 49.0, p < 0.001) and chronic obstructive pulmonary disease (OR = 9.8, p = 0.02) were associated with late-onset infections., Conclusions: Our study findings suggest that risk factors associated with early- and late-onset ICD infection are different. While circumstances that may increase the chances of pocket contamination in the perioperative period are more likely to be associated with early-onset ICD infection, overall poor health of the host may increase the likelihood of late-onset ICD infection. These factors should be considered when developing strategies to minimize risk of device infection.

Purpose: PR-104 is activated by reductases under hypoxia or by aldo-keto reductase 1C3 (AKR1C3) to form cytotoxic nitrogen mustards. Hepatocellular carcinoma (HCC) displays extensive hypoxia and expresses AKR1C3. This study evaluated the safety and efficacy of PR-104 plus sorafenib in HCC., Methods: Patients with advanced-stage HCC, Child-Pugh A cirrhosis, and adequate organ function, were assigned to dose escalating cohorts of monthly PR-104 in combination with twice daily sorafenib. The plasma pharmacokinetics (PK) of PR-104 and its metabolites were evaluated., Results: Fourteen (11 men, 3 women) HCC patients: median age 60 years, ECOG 0-1, received PR-104 at two dose levels plus sorafenib. Six patients were treated at starting cohort of 770 mg/m(2). In view of one DLT of febrile neutropenia and prolonged thrombocytopenia, a lower PR-104 dose cohort (550 mg/m(2)) was added and accrued 8 patients. One patient had a partial response and three had stable disease of ≥8 weeks in the 770 mg/m(2) cohort. Three patients at the 550 mg/m(2) had stable disease. There were no differences in PK of PR-104 or its metabolites with or without sorafenib, but the PR-104A AUC was twofold higher (P < 0.003) than in previous phase I studies at equivalent dose., Conclusions: PR-104 plus sorafenib was poorly tolerated in patients with advanced HCC, possibly because of compromised clearance of PR-104A in this patient population. Thrombocytopenia mainly and neutropenia were the most clinically significant toxicities and led to discontinuation of the study. PR-104 plus sorafenib is unlikely to be suitable for development in this setting.

Fungal prosthetic valve endocarditis is a rare but devastating disease. To better characterise this syndrome, we retrospectively reviewed 21 cases of fungal prosthetic valve endocarditis seen at Mayo Clinic over the past 40 years. The average patient age was 65 years with a 2 : 1 male predominance. Twelve of 21 cases (57%) occurred within 1 year of prosthetic valve placement. The aortic valve was most commonly affected, and the most common aetiological agent was Candida species, followed by Histoplasma capsulatum. Although 20 of 21 patients (95%) were immunocompetent, they had other risk factors for fungal infection. Patients typically presented with systemic signs and symptoms of infection, and cardiac imaging was abnormal in 68% of cases. Pathological evaluation of valve material was of high yield, with organisms identified in 92% of cases who underwent valve replacement surgery or had an autopsy performed. Prosthetic valve fungal endocarditis was associated with a high morbidity and mortality, with 67% of patients experiencing complications and 57% of patients dying of infection-related disease. Hopefully, with the prompt institution of early medical therapy, surgical intervention and lifelong oral antifungal suppressive therapy, cure rates will continue to improve., (© 2010 Blackwell Verlag GmbH.)

PR-104, the phosphate ester of a dinitrobenzamide mustard [PR-104A; 2-((2-bromoethyl)-2-{[(2-hydroxyethyl) amino] carbonyl}-4,6-dinitroanilino)ethyl methanesulfonate], is currently in clinical trial as a hypoxia- and aldo-keto reductase 1C3 (AKR1C3)-activated prodrug for cancer therapy. Here, we investigate species (human, dog, rat, mouse) differences in metabolism to the corresponding O-glucuronide, PR-104G, and identify the human UDP-glucuronosyltransferase (UGT) isoforms responsible. After intravenous PR-104, plasma area under the concentration-time curve ratios (PR-104G/PR-104A) decreased in the order of dog (2.3) > human (1.3) > mouse (0.03) > rat (0.005). The kinetics of uridine 5'-diphosphoglucuronic acid-dependent glucuronidation by liver microsomes in vitro fitted the single-enzyme Michaelis-Menten equation with similar K(m) (∼150 μM) but differing V(max) (472, 88, 37, and 14 nmol/h/mg for dog, human, rat, and mouse, respectively), suggesting that facile glucuronidation is responsible for the anomalously rapid clearance of PR-104A in dogs. In vitro-in vivo extrapolation of PR-104A glucuronidation kinetics is consistent with this also being a major clearance pathway in humans. Recombinant UGT screening identified UGT2B7 as the only commercially available human isoform able to conjugate PR-104A, and UGT2B7 protein concentrations were highly correlated (r = 0.93) with PR-104A glucuronidation by liver microsomes from 24 individuals. The active hydroxylamine metabolite of PR-104A, PR-104H, was also glucuronidated by UGT2B7, although with slightly lower specificity and much lower rates. UGT2B7 mRNA expression was highly variable in human tumor databases. Glucuronidation of PR-104A greatly suppressed nitroreduction by AKR1C3 and NADPH-supplemented anoxic human liver S9 (9000g postmitochondrial supernatant). In conclusion, PR-104A is glucuronidated by UGT2B7 with high specificity and seems to make a major contribution to clearance of PR-104A in humans, but it also has the potential to confer resistance in some human tumors.

Hypoxia is a feature of most tumours, albeit with variable incidence and severity within a given patient population. It is a negative prognostic and predictive factor owing to its multiple contributions to chemoresistance, radioresistance, angiogenesis, vasculogenesis, invasiveness, metastasis, resistance to cell death, altered metabolism and genomic instability. Given its central role in tumour progression and resistance to therapy, tumour hypoxia might well be considered the best validated target that has yet to be exploited in oncology. However, despite an explosion of information on hypoxia, there are still major questions to be addressed if the long-standing goal of exploiting tumour hypoxia is to be realized. Here, we review the two main approaches, namely bioreductive prodrugs and inhibitors of molecular targets upon which hypoxic cell survival depends. We address the particular challenges and opportunities these overlapping strategies present, and discuss the central importance of emerging diagnostic tools for patient stratification in targeting hypoxia.

Background: PR-104 is a phosphate ester that is systemically converted to the corresponding alcohol PR-104A. The latter is activated by nitroreduction in tumours to cytotoxic DNA cross-linking metabolites. Here, we report a population pharmacokinetic (PK) model for PR-104 and PR-104A in non-human species and in humans., Methods: A compartmental model was used to fit plasma PR-104 and PR-104A concentration-time data after intravenous (i.v.) dosing of humans, Beagle dogs, Sprague-Dawley rats and CD-1 nude mice. Intraperitoneal (i.p.) PR-104 and i.v. PR-104A dosing of mice was also investigated. Protein binding was measured in plasma from each species. Unbound drug clearances and volumes were scaled allometrically., Results: A two-compartment model described the disposition of PR-104 and PR-104A in all four species. PR-104 was cleared rapidly by first-order (mice, rats, dogs) or mixed-order (humans) metabolism to PR-104A in the central compartment. The estimated unbound human clearance of PR104A was 211 L/h/70 kg, with a steady state unbound volume of 105 L/70 kg. The size equivalent unbound PR-104A clearance was 2.5 times faster in dogs, 0.78 times slower in rats and 0.63 times slower in mice, which may reflect reported species differences in PR-104A O-glucuronidation., Conclusions: The PK model demonstrates faster size equivalent clearance of PR-104A in dogs and humans than rodents. Dose-limiting myelotoxicity restricts the exposure of PR-104A in humans to approximately 25% of that achievable in mice.

Background: Cardiovascular implantable electronic device (CIED)-related infective endocarditis (CIED-IE) is a serious complication of cardiac device infection and is associated with increased mortality. At present, there exist no criteria to predict CIED-IE in patients who present with CIED infection., Methods: We retrospectively reviewed all cases of CIED infection seen at Mayo Clinic Rochester between 1991 and 2008. CIED-IE was classified using pathologic and clinical criteria. Clinical predictors of CIED-IE were identified using logistic regression, and quantified using a summary score and plotted against the distribution of CIED-IE., Results: Ninety-three (22.4%) of the 416 patients with CIED infection had CIED-IE. Host factors including chronic immunomodulator therapy exclusive of corticosteroid (odds ratio [OR], 3.79 [confidence interval (CI) 1.10, 13.04]), chronic corticosteroid therapy (OR, 2.15 [CI 0.93, 5.00]), hemodialysis (OR, 3.24 [CI 1.39, 7.55]), or remote infection (OR, 1.77 [CI 0.99, 3.14]) were associated with increased odds of CIED-IE. Patients with CIED-IE were at increased odds of presenting with fever (OR, 3.78 [CI 1.93, 7.40]), or malaise (OR, 1.87 [CI 1.02, 3.41]), and have findings of leukocytosis (OR, 3.61 [CI 1.51, 8.62]). In marked contrast, they were at decreased odds of exhibiting signs/symptoms of infection at the generator pocket site (OR, 0.19 [CI 0.10, 0.36]). Summary scores of 6 and 11 predicted CIED-IE in approximately 50% and 90% of cases, respectively., Conclusions: Certain comorbid conditions and systemic manifestations of infection were associated with CIED-IE. In contrast, pocket site infection was negatively associated with CIED-IE. These findings should assist clinicians in identifying patients who would more likely benefit from further investigation of CIED-IE with transesophageal echocardiography., (©2010, The Authors. Journal compilation ©2010 Wiley Periodicals, Inc.)

Purpose: PR-104, a bioreductive prodrug in clinical trial, is a phosphate ester which is rapidly metabolized to the corresponding alcohol PR-104A. This dinitrobenzamide mustard is activated by reduction to hydroxylamine (PR-104H) and amine (PR-104M) metabolites selectively in hypoxic cells, and also independently of hypoxia by aldo-keto reductase (AKR) 1C3 in some tumors. Here, we evaluate reductive metabolism of PR-104A in mice and its significance for host toxicity., Methods: The pharmacokinetics of PR-104, PR-104A and its reduced metabolites were investigated in plasma and tissues of mice (with and without SiHa or H460 tumor xenografts) and effects of potential oxidoreductase inhibitors were evaluated., Results: Pharmacokinetic studies identified extensive non-tumor reduction of PR-104A to the 5-amine PR-104H (identity of which was confirmed by chemical synthesis), especially in liver. However, high concentrations of PR-104H in tumors that suggested intra-tumor activation is also significant. The tissue distribution of PR-104M/H was broadly consistent with the target organ toxicities of PR-104 (bone marrow, intestines and liver). Surprisingly, hepatic nitroreduction was not enhanced when the liver was made more hypoxic by hepatic artery ligation or breathing of 10% oxygen. A screen of non-steroidal anti-inflammatory drugs identified naproxen as an effective AKR1C3 inhibitor in human tumor cell cultures and xenografts, suggesting its potential use to ameliorate PR-104 toxicity in patients. However, neither naproxen nor the pan-CYP inhibitor 1-aminobenzotriazole inhibited normal tissue reduction of PR-104A in mice., Conclusions: PR-104 is extensively reduced in mouse tissues, apparently via oxygen-independent two-electron reduction, with a tissue distribution that broadly reflects toxicity.

Background: The purpose of this statement is to update the recommendations by the American Heart Association (AHA) for cardiovascular implantable electronic device (CIED) infections and their management, which were last published in 2003., Methods and Results: The AHA commissioned this scientific statement to educate clinicians about CIED infections, provide explicit recommendations for the care of patients with suspected or established CIED infections and highlight areas of needed research. The recommendations in this statement reflect analyses of relevant literature, to include recent advances in our understanding of the epidemiology, risk factors, microbiology, management and prevention of CIED infections., Conclusion: There are no scientific data to support the use of antimicrobial prophylaxis for dental or other invasive procedures., Clinical Implications: The concerns about life-threatening drug reactions, the development of resistant strains of bacterial pathogens, medicolegal issues and cost to the health care system are, thus, avoided.

Recent studies indicate that interactions between leukemia cells and the bone marrow (BM) microenvironment promote leukemia cell survival and confer resistance to anti-leukemic drugs. There is evidence that BM microenvironment contains hypoxic areas that confer survival advantage to hematopoietic cells. In the present study we investigated whether hypoxia in leukemic BM contributes to the protective role of the BM microenvironment. We observed a marked expansion of hypoxic BM areas in immunodeficient mice engrafted with acute lymphoblastic leukemia (ALL) cells. Consistent with this finding, we found that hypoxia promotes chemoresistance in various ALL derived cell lines. These findings suggest to employ hypoxia-activated prodrugs to eliminate leukemia cells within hypoxic niches. Using several xenograft models, we demonstrated that administration of the hypoxia-activated dinitrobenzamide mustard, PR-104 prolonged survival and decreased leukemia burden of immune-deficient mice injected with primary acute lymphoblastic leukemia cells. Together, these findings strongly suggest that targeting hypoxia in leukemic BM is feasible and may significantly improve leukemia therapy.

Background: Infection is a serious complication of cardiovascular implantable electronic device (CIED) placement and requires device removal for attempted cure., Methods and Results: We studied the rate, risk factors, and outcomes of CIED infection in 74 consecutive patients with bacteremia caused by Gram-positive cocci (GPC) other than Staphylococcus aureus between 2001 and 2007. CIED infection was defined as the presence of signs of infection at the generator site, lead vegetations seen on echocardiography, or microbiological growth from device cultures. Twenty-two (30%) of 74 patients with non-S aureus GPC bacteremia had CIED infections. Coagulase-negative staphylococci (CoNS) accounted for 73% of CIED infections. The rate of CIED infection in patients with CoNS bacteremia was almost 2-fold that of non-CoNS GPC bacteremia (36% versus 20%, P = 0.13). The number of leads, the presence of abandoned leads, and prior generator replacement were associated with CIED infection. Among 33 patients without identifiable CIED infection at initial evaluation who did not undergo device removal, 5 (15%) had relapsing bacteremia within 12 weeks of completing antibiotic therapy. CoNS accounted for all relapses, and none had evidence of CIED infection at relapse., Conclusions: Patients with a CIED and bacteremia caused by GPC other than S aureus frequently had evidence of underlying CIED infection on clinical evaluation that included transesophageal echocardiography. This was particularly true among those with CoNS bacteremia. No evidence of underlying CIED infections was identified in the subgroup of patients who did not have manifestations of CIED infection on initial evaluation but subsequently had relapsing bacteremia caused by CoNS.

Purpose: Tirapazamine (TPZ) has attractive features for targeting hypoxic cells in tumors but has limited clinical activity, in part because of poor extravascular penetration. Here, we identify improved TPZ analogues by using a spatially resolved pharmacokinetic/pharmacodynamic (SR-PKPD) model that considers tissue penetration explicitly during lead optimization., Experimental Design: The SR-PKPD model was used to guide the progression of 281 TPZ analogues through a hierarchical screen. For compounds exceeding hypoxic selectivity thresholds in single-cell cultures, SR-PKPD model parameters (kinetics of bioreductive metabolism, clonogenic cell killing potency, diffusion coefficients in multicellular layers, and plasma pharmacokinetics at well tolerated doses in mice) were measured to prioritize testing in xenograft models in combination with radiation., Results: SR-PKPD-guided lead optimization identified SN29751 and SN30000 as the most promising hypoxic cytotoxins from two different structural subseries. Both were reduced to the corresponding 1-oxide selectively under hypoxia by HT29 cells, with an oxygen dependence quantitatively similar to that of TPZ. SN30000, in particular, showed higher hypoxic potency and selectivity than TPZ in tumor cell cultures and faster diffusion through HT29 and SiHa multicellular layers. Both compounds also provided superior plasma PK in mice and rats at equivalent toxicity. In agreement with SR-PKPD predictions, both were more active than TPZ with single dose or fractionated radiation against multiple human tumor xenografts., Conclusions: SN30000 and SN29751 are improved TPZ analogues with potential for targeting tumor hypoxia in humans. Novel SR-PKPD modeling approaches can be used for lead optimization during anticancer drug development., (©2010 AACR.)

The aim of this study was to evaluate the efficacy and safety of rifampin for Staphylococcus aureus (SA) or coagulase negative staphylococci (CNS) prosthetic joint infection (PJI) treated with debridement and retention (D/R). We calculated the treatment failure cumulative incidence (TF) of a cohort of 101 patients with SA or CNS PJI treated with D/R and antimicrobial therapy. The effect of the use of a rifampin-based regimen was evaluated. Cox proportional hazards regression evaluated the association between treatment and time-to-TF controlling for the propensity to treat with rifampin and temporal confounders. Seven percent (1/14) of the prospective rifampin-treated patients, 32% (10/31) of the historical rifampin-treated patients and 38% (21/56) of the historical non-rifampin treated patients developed TF. After controlling for the propensity to treat with rifampin and American Society of Anesthesia scores, patients in the prospective cohort had a lower risk of TF compared to patients in the historical cohort not treated with rifampin (HR 0.11; 95%CI 0.01-0.84). None (0/14) of the patients in the prospective study developed hepatotoxicity. The outcome of staphylococcal PJI treated with D/R and rifampin-based regimens was better when compared with a historical cohort treated without rifampin.

Background: The nature of the inflammatory change within ruptured AAA has not been extensively reported. The aim of this study was to compare the inflammatory response in non-ruptured and ruptured aneurysms with emphasis on the site of rupture., Methods: Non-rupture site biopsies were taken from the anterior aneurysm sac of non-ruptured (n=31) and ruptured AAA (n=20). In 12 ruptured AAA, a further biopsy was taken from the rupture site. Enzyme-linked immunosorbent assay was used to quantify IL-6, IL-1beta and TNF-alpha. Quantitative immunohistochemistry was undertaken for generic lymphocytes, T-cells, and B-cells., Results: Comparing biopsies in non-ruptured AAA versus a non-rupture site biopsy from ruptured AAA; there was no significant difference in IL-6, IL-1beta, TNF-alpha, generic lymphocytes, T-cell or B-cell content. Comparing ruptured AAA--non-rupture site with rupture site; IL-6 and TNF-alpha were unchanged. By contrast IL-1beta and lymphocytes were lower at the rupture site compared to the non-rupture site (IL-1beta 1.39 ng/mg [0.97-2.29] vs. 1.92 ng/mg [1.46-2.57], p=0.027; generic lymphocytes 2.89% [0.51-5.51] vs. 4.73% [2.27-12.40], p=0.018; T-cells 0.28% [0.04-1.18] vs. 0.82% [0.40-1.36], p=0.027; B-cells 0.16% [0.04-1.14] vs. 1.30% [0.32-5.40], p=0.021)., Conclusions: These findings suggest the biological events leading to AAA rupture may not be dependent on an up-regulation in the inflammatory process., (Copyright (c) 2010 European Society for Vascular Surgery. Published by Elsevier Ltd. All rights reserved.)

Nitro seco-1,2,9,9a-tetrahydrocyclopropa[c]benz[e]indol-4-ones (nitroCBIs) are a new class of prodrugs for antitumor therapy that undergo hypoxia-selective metabolism to form potent DNA minor groove alkylating agents. Although hindered by poor aqueous solubility, several examples have shown activity against hypoxic tumor cells in vivo. Here we investigate structural properties that influence hypoxic selectivity in vitro, and show that for high hypoxic selectivity nitroCBIs should combine an electron-withdrawing group of H-bond donor capacity on the A-ring, with a basic substituent on the minor groove-binding side chain. Substitution on the A-ring is compatible with the introduction of functionality that can improve water solubility., (Copyright (c) 2010 Elsevier Ltd. All rights reserved.)

Objective: Abdominal aortic aneurysm (AAA) development is associated with increased angiogenesis and overexpression of vascular endothelial growth factor (VEGF). Inhibition of angiogenesis results in attenuation of experimental aneurysms. This study investigated the effects of recombinant human (rh)VEGF on experimental aneurysms., Methods: Apolipoprotein E-deficient (apoE(-/-)) mice were assigned to one of four groups: (1) normal saline infusion (sham), (2) angiotensin-II (AngII) infusion, (3) AngII infusion plus 100 microg daily rhVEGF for 14 days (AngII+14dVEGF), or (4) AngII infusion plus 100 microg daily rhVEGF for 21 days (AngII+21dVEGF). Aortic maximum diameter and cross-sectional area were determined by magnetic resonance imaging and microscopy. All mice were sacrificed at day 28., Results: Aneurysms developed in all mice in the AngII+14dVEGF and AngII+21dVEGF groups by day 21 compared with 40% in the AngII group. Treatment with rhVEGF increased maximum aortic diameter (P < .002) and cross-sectional area of aneurysms (P < .005) at day 21. This effect was maintained at day 28 (P < .0005). Decreasing rhVEGF treatment from 21 to 14 days did not attenuate aneurysm formation. Treatment with rhVEGF upregulated matrix metalloproteinase 2 gene expression within the aortic wall (P < .0009)., Conclusions: Treatment with rhVEGF intensified the formation of AngII-induced aneurysms. Further studies are needed to investigate if antiangiogenic therapy may be a valid medical therapy against aneurysm expansion or rupture., (Copyright (c) 2010 Society for Vascular Surgery. Published by Mosby, Inc. All rights reserved.)

Objective: To provide a contemporary profile of epidemiological trends of infective endocarditis (IE) in Olmsted County, Minnesota., Patients and Methods: This study consists of all definite or possible IE cases among adults in Olmsted County from January 1, 1970, through December 31, 2006. Cases were identified using resources of the Rochester Epidemiology Project., Results: We identified 150 cases of IE. The age- and sex-adjusted incidences of IE ranged from 5.0 to 7.9 cases per 100,000 person-years with an increasing trend over time differential with respect to sex (for interaction, P=.02); the age-adjusted incidence of IE increased significantly in women (P=.006) but not in men (P=.79). We observed an increasing temporal trend in the mean age at diagnosis (P=.04) and a decreasing trend in the proportion of cases with rheumatic heart disease as a predisposing condition (P=.02). There were no statistically significant temporal trends in the incidence of either Staphylococcus aureus or viridans group streptococcal IE. Data on infection site of acquisition were available for cases seen in 2001 and thereafter, with 50.0% designated as health care-associated, 42.5% community-acquired, and 7.5% nosocomial., Conclusion: The incidence of IE among women increased from 1970 to 2006. Ongoing surveillance is warranted to determine whether the incidence change in women will be sustained. Subsequent analysis of infection site of acquisition and its impact on the epidemiology of IE are planned.

Background: Staphylococcus aureus bacteremia (SAB) in patients with cardiovascular implantable electronic devices (CIED), including permanent pacemakers (PPMs) and implantable cardioverter-defibrillators (ICD), can be the sole manifestation of device infection., Methods: To assess clinical factors associated with CIED infection, we retrospectively reviewed all patients with both CIED and SAB seen at Mayo Clinic Rochester between 2001 through 2006. CIED infection was defined using microbiological and clinical criteria., Results: Of the 62 patients with SAB and a CIED, 22 patients (35.5%) had CIED infection. The generator pocket was identified as the source of bacteremia in seven (11%) patients. The majority of CIED infections were device-related infective endocarditis (12 of 22, 55%). Thirty percent of patients presenting with SAB greater than 1 year after device implantation had CIED infection; all but one had CIED-related infective endocarditis. Sixty percent of ICD patients (12 of 20) with SAB had CIED infection, compared with 24% of PPM patients (10 of 42, P = 0.01). On univariate analysis factors associated with CIED-related infective endocarditis included device type [odds ratio (OR) for ICD 13.3, 95% confidence interval [CI] 2.1, 84.9) and presence of a prosthetic heart valve (OR 6.8 95% CI 1.1, 43.4)., Conclusions: CIED infection is common in patients with SAB. The presence of an ICD and prosthetic heart valve were associated with CIED-related infective endocarditis. Subsequent work should focus on prospectively characterizing the subset of patients with CIED infection who present with SAB as the sole manifestation of their device infection. (PACE 2010; 407-413).

Purpose: PR-104 is a "pre-prodrug" designed to be activated to a dinitrobenzamide nitrogen mustard cytotoxin by nitroreduction in hypoxic regions of tumors. This study was conducted to establish the maximum tolerated dose (MTD), dose-limiting toxicity (DLT), safety, and pharmacokinetics (PK) of PR-104 in patients with advanced solid tumors., Methods: Patients with solid tumors refractory or not amenable to conventional treatment were evaluated in a dose-escalation trial of PR-104 administered as a 1-h intravenous (IV) infusion every 3 weeks. The plasma PK of PR-104 and its primary metabolite, PR-104A, were evaluated., Results: Twenty-seven patients received a median of two cycles of PR-104 in doses ranging from 135 to 1,400 mg/m(2). The MTD of PR-104 as a single-dose infusion every 3 weeks was established as 1,100 mg/m(2). One of six patients treated at 1,100 mg/m(2) experienced DLT of grade 3 fatigue. Above the MTD, the DLTs at 1,400 mg/m(2) were febrile neutropenia and infection with normal absolute neutrophil count. No objective responses were observed, although reductions in tumor size were observed in patients treated at doses > or = 550 mg/m(2). The plasma PK of PR-104 demonstrated rapid conversion to PR-104A, with approximately dose-linear PK of both species., Conclusions: PR-104 was well tolerated at a dose of 1,100 mg/m(2) administered as an IV infusion every 3 weeks. The area under the PR-104A plasma concentration-time curve at this dose exceeded that required for activity in human tumor cell cultures and xenograft models. The recommended dose of PR-104 as a single agent for phase II trials is 1,100 mg/m(2) and further trials are underway.

Gene-directed enzyme prodrug therapy (GDEPT) aims to achieve highly selective tumor-cell killing through the use of tumor-tropic gene delivery vectors coupled with systemic administration of otherwise inert prodrugs. Nitroaromatic prodrugs such as CB1954 hold promise for GDEPT as they are readily reduced to potent DNA alkylating agents by bacterial nitroreductase enzymes (NTRs). Transfection with the nfsB gene from Escherichia coli can increase the sensitivity of tumor cells to CB1954 by greater than 1000-fold. However, poor catalytic efficiency limits the activation of CB1954 by NfsB at clinically relevant doses. A lack of flexible, high-throughput screening technology has hindered efforts to discover superior NTR candidates. Here we demonstrate how the SOS chromotest and complementary screening technologies can be used to evaluate novel enzymes that activate CB1954 and other bioreductive and/or genotoxic prodrugs. We identify the major E. coli NTR, NfsA, as 10-fold more efficient than NfsB in activating CB1954 as purified protein (k(cat)/K(m)) and when over-expressed in an E. coli nfsA(-)/nfsB(-) gene deleted strain. NfsA also confers sensitivity to CB1954 when expressed in HCT-116 human colon carcinoma cells, with similar efficiency to NfsB. In addition, we identify two novel E. coli NTRs, AzoR and NemA, that have not previously been characterized in the context of nitroaromatic prodrug activation., (2009 Elsevier Inc. All rights reserved.)

PR-104 is the phosphate ester of a 3,5-dinitrobenzamide nitrogen mustard (PR-104A) that is reduced to active hydroxylamine and amine metabolites by reductases in tumors. In this study, we evaluate the excretion of [(3)H]PR-104 in mice and determine its metabolite profile in mice, rats, dogs, and humans after a single intravenous dose. Total radioactivity was rapidly and quantitatively excreted in mice, with cumulative excretion of 46% in urine and 50% in feces. The major urinary metabolites in mice were products from oxidative N-dealkylation and/or glutathione conjugation of the nitrogen mustard moiety, including subsequent mercapturic acid pathway metabolites. A similar metabolite profile was seen in mouse bile, mouse plasma, and rat urine and plasma. Dogs and humans also showed extensive thiol conjugation but little evidence of N-dealkylation. Humans, like rodents, showed appreciable reduced metabolites in plasma, but concentrations of the cytotoxic amine metabolite (PR-104M) were higher in mice than humans. The most conspicuous difference in metabolite profile was the much more extensive O-beta-glucuronidation of PR-104A in dogs and humans than in rodents. The structure of the O-beta-glucuronide (PR-104G) was confirmed by independent synthesis. Its urinary excretion was responsible for 13 +/- 2% of total dose in humans but only 0.8 +/- 0.1% in mice. Based on these metabolite profiles, biotransformation of PR-104 in rodents is markedly different from that in humans, suggesting that rodents may not be appropriate for modeling human biotransformation and toxicology of PR-104.

PR-104, currently in phase II clinical trials, is a phosphate ester pre-prodrug which is converted in vivo to its cognate alcohol, PR-104A, a prodrug designed to exploit tumor hypoxia. Bioactivation occurs via one-electron reduction to DNA crosslinking metabolites in the absence of oxygen. However, certain tumor cell lines activate PR-104A in the presence of oxygen, suggesting the existence of an aerobic nitroreductase. Microarray analysis identified a cluster of five aldo-keto reductase (AKR) family members whose expressions correlated with aerobic metabolism of PR-104A. Plasmid-based expression of candidate genes identified aldo-keto reductase 1C3 as a novel nitroreductase. AKR1C3 protein was detected by Western blot in 7 of 23 cell lines and correlated with oxic PR-104A metabolism, an activity which could be partially suppressed by Nrf2 RNAi knockdown (or induced by Keap1 RNAi), indicating regulation by the ARE pathway. AKR1C3 was unable to sensitize cells to 10 other bioreductive prodrugs and was associated with single-agent PR-104 activity across a panel of 9 human tumor xenograft models. Overexpression in two AKR1C3-negative tumor xenograft models strongly enhanced PR-104 antitumor activity. A population level survey of AKR1C3 expression in 2,490 individual cases across 19 cancer types using tissue microarrays revealed marked upregulation of AKR1C3 in a subset including hepatocellular, bladder, renal, gastric, and non-small cell lung carcinoma. A survey of normal tissue AKR1C3 expression suggests the potential for tumor-selective PR-104A activation by this mechanism. These findings have significant implications for the clinical development of PR-104.

Objective: Survivor bias commonly weakens observational studies, even those published in premier journals. It occurs because patients who live longer are more likely to receive treatment than those who die early. We sought to quantify the effect of survivor bias on the association between valve surgery and mortality in infective endocarditis (IE)., Study Design and Setting: The study cohort included 546 IE patients. We compared the hazard ratios (HR) resulting from two propensity score analysis approaches that adjusted for survivor bias (time-dependent variable and matching on follow-up time) with those achieved using the same models but without that adjustment (time-fixed variable)., Results: In the total cohort, the HR of surgery in the time-dependent model was 1.9 (95% confidence interval [CI] = 1.1-3.2; P = 0.03) vs. 0.9 (95% CI = 0.5-1.4; P = 0.53) in the time-fixed model. In the propensity score-matched subset, the HR of surgery was 1.3 (95% CI = 0.5-3.1; P = 0.56) and 0.8 (95% CI = 0.4-1.7; P = 0.57) in the subset with and without matching on follow-up time, respectively., Conclusion: Adjusting for survivor bias changed the conclusion about the association between valve surgery and mortality in IE. Researchers should be aware of this bias when evaluating observational studies of treatment efficacy., (Copyright 2010 Elsevier Inc. All rights reserved.)

Data on the burden of disease from tuberculosis (TB) in Filipino households are limited. To determine the magnitude of undiagnosed TB in TB households, and the demographic and socio-economic factors associated with TB in the Philippines, household contacts of adult smear-positive TB patients seen from July 2001 to June 2003 were assessed based on interview, chest X-ray, tuberculin skin test and sputum examination. History of TB and older age were independently associated with TB disease, and age and duration of cohabitation with TB infection. TB and TB infection are highly prevalent in TB households in the Philippines.

Background: The actual risk of prosthetic joint infection as a result of dental procedures and the role of antibiotic prophylaxis have not been defined., Methods: To examine the association between dental procedures with or without antibiotic prophylaxis and prosthetic hip or knee infection, a prospective, single-center, case-control study for the period 2001-2006 was performed at a 1200-bed tertiary care hospital in Rochester, Minnesota. Case patients were patients hospitalized with total hip or knee infection. Control subjects were patients who underwent a total hip or knee arthroplasty but without a prosthetic joint infection who were hospitalized during the same period on the same orthopedic floor. Data regarding demographic features and potential risk factors were collected. Logistic regression was used to assess the association of variables with the odds of infection., Results: A total of 339 case patients and 339 control subjects were enrolled in the study. There was no increased risk of prosthetic hip or knee infection for patients undergoing a high-risk or low-risk dental procedure who were not administered antibiotic prophylaxis (adjusted odds ratio [OR], 0.8; 95% confidence interval [CI], 0.4-1.6), compared with the risk for patients not undergoing a dental procedure (adjusted OR, 0.6; 95% CI, 0.4-1.1) respectively. Antibiotic prophylaxis in high-risk or low-risk dental procedures did not decrease the risk of subsequent total hip or knee infection (adjusted OR, 0.9 [95% CI, 0.5-1.6] and 1.2 [95% CI, 0.7-2.2], respectively)., Conclusions: Dental procedures were not risk factors for subsequent total hip or knee infection. The use of antibiotic prophylaxis prior to dental procedures did not decrease the risk of subsequent total hip or knee infection.