Metabolic analysis of the response of Pseudomonas putida DOT-T1E strains to toluene using Fourier transform infrared spectroscopy and gas chromatography mass spectrometry.

INTRODUCTION: An exceptionally interesting stress response of Pseudomonas putida strains to toxic substances is the induction of efflux pumps that remove toxic chemical substances from the bacterial cell out to the external environment. To exploit these microorganisms to their full potential a deeper understanding of the interactions between the bacteria and organic solvents is required. Thus, this study focuses on investigation of metabolic changes in P. putida upon exposure to toluene. OBJECTIVE: Investigate observable metabolic alterations during interactions of three strains of P. putida (DOT-T1E, and its mutants DOT-T1E-PS28 and DOT-T1E-18) with the aromatic hydrocarbon toluene. METHODS: The growth profiles were measured by taking optical density (OD) measurement at 660 nm (OD660) at various time points during incubation. For fingerprinting analysis, Fourier-transform infrared (FT-IR) spectroscopy was used to investigate any phenotypic changes resulting from exposure to toluene. Metabolic profiling analysis was performed using gas chromatography-mass spectrometry (GC-MS). Principal component-discriminant function analysis (PC-DFA) was applied to the FT-IR data while multiblock principal component analysis (MB-PCA) and N-way analysis of variance (N-way ANOVA) were applied to the GC-MS data. RESULTS: The growth profiles demonstrated the effect of toluene on bacterial cultures and the results suggest that the mutant P. putida DOT-T1E-18 was more sensitive (significantly affected) to toluene compared to the other two strains. PC-DFA on FT-IR data demonstrated the differentiation between different conditions of toluene on bacterial cells, which indicated phenotypic changes associated with the presence of the solvent within the cell. Fifteen metabolites associated with this phenotypic change, in P. putida due to exposure to solvent, were from central metabolic pathways. Investigation of MB-PCA loading plots and N-way ANOVA for condition | strain × time blocking (dosage of toluene) suggested ornithine as the most significant compound that increased upon solvent exposure. CONCLUSION: The combination of metabolic fingerprinting and profiling with suitable multivariate analysis revealed some interesting leads for understanding the mechanism of Pseudomonas strains response to organic solvent exposure.

Results of a Randomized Controlled Multicenter Phase III Trial of Percutaneous Hepatic Perfusion Compared with Best Available Care for Patients with Melanoma Liver Metastases.

PURPOSE: There is no consensus for the treatment of melanoma metastatic to the liver. Percutaneous hepatic perfusion with melphalan (PHP-Mel) is a method of delivering regional chemotherapy selectively to the liver. In this study, we report the results of a multicenter, randomized controlled trial comparing PHP-Mel with best alternative care (BAC) for patients with ocular or cutaneous melanoma metastatic to the liver. PATIENTS AND METHODS: A total of 93 patients were randomized to PHP-Mel (n = 44) or BAC (n = 49). On the PHP-Mel arm, melphalan was delivered via the hepatic artery, and the hepatic effluent captured and filtered extracorporeally prior to return to the systemic circulation via a venovenous bypass circuit. PHP-Mel was repeatable every 4-8 weeks. The primary endpoint was hepatic progression-free survival (hPFS), and secondary endpoints included overall PFS (oPFS), overall survival (OS), hepatic objective response (hOR), and safety. RESULTS: hPFS was 7.0 months for PHP-Mel and 1.6 months for BAC (p < 0.0001), while oPFS was 5.4 months for PHP-Mel and 1.6 months for BAC (p < 0.0001). Median OS was not significantly different (PHP-Mel 10.6 months vs. BAC 10.0 months), likely due to crossover to PHP-Mel treatment (57.1 %) from the BAC arm, and the hOR was 36.4 % for PHP-Mel and 2.0 % for BAC (p < 0.001). The majority of adverse events were related to bone marrow suppression. Four deaths were attributed to PHP-Mel, three in the primary PHP-Mel group, and one post-crossover to PHP-Mel from BAC. CONCLUSION: This randomized, phase III study demonstrated the efficacy of the PHP-Mel procedure. hPFS, oPFS, and hOR were significantly improved with PHP-Mel. PHP with melphalan should provide a new treatment option for unresectable metastatic melanoma in the liver.

Duodenal ischemia and upper GI bleeding are dose-limiting toxicities of 24-h continuous intra-arterial pancreatic perfusion of gemcitabine following vascular isolation of the pancreatic head: early results from the Regional Chemotherapy in Locally Advanced Pancreatic Cancer (RECLAP) study.

BACKGROUND: Regional chemotherapy is used successfully in the treatment of both primary and secondary malignancies, in particular of the peritoneal surface and the liver, and is currently explored as an attractive approach for patients with locally advanced pancreatic ductal adenocarcinoma. To establish the feasibility and toxicity of regional intra-arterial gemcitabine delivered as a 24-h continuous infusion to the pancreas as a novel treatment option for patients with locally advanced PDAC a phase I clinical trial was conducted. METHODS: Between April 2011 and September 2013 six patients with biopsy confirmed, borderline or unresectable pancreatic adenocarcinoma, and having received at least one line of systemic chemotherapy, underwent vascular redistribution of the inflow to the head of the pancreas by arterial coil embolization followed by perfusion catheter placement within the splenic artery. Patients were treated with increasing doses of gemcitabine administered by continuous splenic arterial infusion over 24 h with inter-patient and intra-patient dose escalation scheme. The primary endpoint was toxicity of the intra-arterial gemcitabine regimen and to establish the maximum tolerated dose. RESULTS: Catheter placement and gemcitabine infusion was successful in all patients enrolled to date (n = 6). Four out of six patients experienced catheter tip migration requiring replacement or revision. Patients received a median of four doses of 24-h gemcitabine infusion. Two patients developed grade 3 and 4 duodenal ischemia and upper gastrointestinal bleeding. Median overall survival was 15.3 months and median time to progression was 3 months. Three patients (50 %, n = 3/6) progressed systemically. Two patients had stable disease >4 months following treatment and underwent pancreaticoduodenectomy. CONCLUSIONS: While technically feasible to treat locally advanced pancreatic ductal adenocarcinoma, prolonged regional pancreatic perfusion with gemcitabine following pancreatic arterial redistribution carries a high risk for gastrointestinal toxicity. Shorter infusion schedules with frequent on treatment evaluations should be considered for future clinical trials.

Impact of maximal cytoreductive surgery plus regional heated intraperitoneal chemotherapy (HIPEC) on outcome of patients with peritoneal carcinomatosis of gastric origin: results of the GYMSSA trial.

BACKGROUND: A prospective randomized trial was conducted to compare the impact of systemic chemotherapy versus multi-modality therapy (complete cytoreductive surgery (CRS), hyperthermic intraperitoneal chemotherapy (HIPEC), and systemic chemotherapy) on overall survival (OS) in patients with gastric carcinomatosis. METHODS: Patients with measurable metastatic gastric adenocarcinoma involving the peritoneum, and resectable to "no evidence of disease" were randomized to gastrectomy, metastasectomy, HIPEC, and systemic FOLFOXIRI (GYMS arm) or FOLFOXIRI alone (SA arm). RESULTS: Seventeen patients were enrolled (16 evaluable); 7 of 9 patients in the multi-modality GYMS arm achieved complete cytoreduction (CCR0). Median OS was 11.3 months in the GYMS arm and 4.3 months in the SA arm. Four patients in the GYMS arm survived >12 months, 2 patients close to 2 years at last follow-up, and 1 patient more than 4 years, with 2 of these patients still alive. No patient in the SA arm lived beyond 11 months. All patients surviving beyond 12 months in the surgery arm achieved complete cytoreduction and had an initial Peritoneal Cancer Index (PCI) of ≤ 15. CONCLUSION: Maximal cytoreductive surgery combined with regional (HIPEC) and systemic chemotherapy in selected patients with gastric carcinomatosis and limited disease burden can achieve prolonged survival.

The effect of long-term left ventricular assist device support on myocardial sympathetic activity in patients with non-ischaemic dilated cardiomyopathy.

AIMS: Dilated cardiomyopathy (DCM) patients have abundant levels of norepinephrine secondary to failure of the norepinephrine transporter uptake mechanism. Little is known about the effects of an LV assist device (LVAD) on cardiac sympathetic innervations and norepinephrine transporter dysfunction. This study examines the effects of continuous-flow HeartMate II LVAD on cardiac sympathetic innervations using [(123)I]metaiodobenzylguanidine ([(123)I]MIBG) nuclear imaging. METHODS AND RESULTS: After injecting 431 ± 21 MBq of [(123)I]MIBG, planar scintigraphy was performed at 15 min and 4 h in 14 consecutive non-diabetic non-ischaemic DCM patients. Scans were executed early post-LVAD implantation (T1) and prior to either device explantation for myocardial recovery or transplant listing (T2). [(123)I]MIBG measured parameters included early and delayed heart-mediastinum (H/M) ratios and washout rate (W/O). Catecholamine levels were measured using liquid chromatography-mass spectrometry. Following 208.4 ± 85.5 days of LVAD support, both early and delayed H/M ratios increased by 42.1% (P < 0.001) and 54.7% (P < 0.001), respectively. The W/O rate decreased by 46% (P = 0.003). Plasma norepinephrine, epinephrine, and dopamine decreased significantly in correlation with [(123)I]MIBG parameters. Ten patients had recovered and had their device explanted as they had demonstrated a higher percentage change in delayed H/M ratio, W/O rate, and norepinephrine levels. Linear regression analysis revealed a strong correlation between percentage changes in both norepinephrine and epinephrine and myocardial recovery. CONCLUSION: Combination therapy with LVAD and drug resulted in enhancement of [(123)I]MIBG uptake in DCM patients.

Reversal of severe heart failure with a continuous-flow left ventricular assist device and pharmacological therapy: a prospective study.

BACKGROUND: We have previously shown that a specific combination of drug therapy and left ventricular assist device unloading results in significant myocardial recovery, sufficient to allow pump removal, in two thirds of patients with dilated cardiomyopathy receiving a Heartmate I pulsatile device. However, this protocol has not been used with nonpulsatile devices. METHODS AND RESULTS: We report the results of a prospective study of 20 patients who received a combination of angiotensin-converting enzymes, ß-blockers, angiotensin II inhibitors, and aldosterone antagonists followed by the ß2-agonist clenbuterol and were regularly tested (echocardiograms, exercise tests, catheterizations) with the pump at low speed. Before left ventricular assist device insertion, patient age was 35.2 ± 12.6 years (16 male patients), patients were on 2.0 ± 0.9 inotropes, 7 (35) had an intra-aortic balloon pump, 2 were hemofiltered, 2 were ventilated, 3 had a prior Levitronix device, and 1 had extracorporeal membrane oxygenation. Cardiac index was 1.39 ± 0.43 L · min⁻¹ · m⁻², pulmonary capillary wedge pressure was 31.5 ± 5.7 mm Hg, and heart failure history was 3.4 ± 3.5 years. One patient was lost to follow-up and died after 240 days of support. Of the remaining 19 patients, 12 (63.2) were explanted after 286 ± 97 days. Eight had symptomatic heart failure for ≤6 months and 4 for >6 months (48 to 132 months). Before explantation, at low flow for 15 minutes, ejection fraction was 70 ± 7, left ventricular end-diastolic diameter was 48.6 ± 5.7 mm, left ventricular end-systolic diameter was 32.3 ± 5.7 mm, mV(O2) was 21.6 ± 4 mL · kg⁻¹ · min⁻¹, pulmonary capillary wedge pressure was 5.9 ± 4.6 mm Hg, and cardiac index was 3.6 ± 0.6 L · min⁻¹ · m⁻². Estimated survival without heart failure recurrence was 83.3 at 1 and 3 years. After a 430.7 ± 337.1-day follow-up, surviving explants had an ejection fraction of 58.1 ± 13.8, left ventricular end-diastolic diameter of 59.0 ± 9.3 mm, left ventricular end-systolic diameter of 42.0 ± 10.7 mm, and mV(O2) of 22.6 ± 5.3 mL · kg⁻¹ · min⁻¹. CONCLUSIONS: Reversal of end-stage heart failure secondary to nonischemic cardiomyopathy can be achieved in a substantial proportion of patients with nonpulsatile flow through the use of a combination of mechanical and pharmacological therapy.

Echocardiographic assessment of flow across continuous-flow ventricular assist devices at low speeds.

BACKGROUND: Testing of native myocardial function in patients with continuous-flow pumps is challenging as reduction/cessation of the pump could result in regurgitation, although the amount and significance of this regurgitation remains unknown. The aim of this study was to determine the optimal speed at which to assess the native left ventricular (LV) function and the physiologic response to speed reduction. METHODS: Fifteen male patients with a HeartMate II (HMII) device were studied prospectively on 46 occasions. Measurements were performed serially at three device speed settings: baseline speed; 6,000 rpm; and either 5,000 rpm (Group A) or 4,000 rpm (Group B). The device's forward and reverse velocity (Vmax(f), Vmax(r)), forward and reverse velocity time integral (VTI(f), VTI(r)) and blood volume (BV) were also measured using Doppler with LV echocardiographic parameters and peripheral hemodynamics. RESULTS: No adverse incidents were reported. Speed reduction to 6,000 rpm resulted in a significant decrease in Vmax(f), VTI(f) and BV. There was no significant difference in either forward or reverse flow with further speed reduction in either group. Speed reduction to <6,000 rpm did not have a significant effect on LV loading. CONCLUSIONS: Speed reduction in patients with the HMII device is safe. There was no difference between 6,000 rpm and lower speeds, suggesting that 6,000 rpm is sufficient to assess native myocardial function. The absence of significant retrograde filling suggests that LV loading is a physiologic response to speed reduction at 6,000 rpm.

Hemodynamic and echocardiographic responses to acute interruption of left ventricular assist device support: relevance to assessment of myocardial recovery.

BACKGROUND: Assessment of myocardial recovery during left ventricular assist device (LVAD) support is difficult to perform both safely and effectively. We developed a test involving short-term interruption of LVAD support with measurements of several hemodynamic and echocardiographic parameters at rest and, whenever possible, after exercise, to investigate inotropic reserve. METHODS: After full heparinization, the HeartMate I XVE device was switched off. MAP, heart rate (HR), ejection fraction (EF) and left ventricular dimensions were measured on switching off, after 5, 10 and 15 minutes, and after 6-minute walk (6MW). RESULTS: In total, 207 serial tests were performed on 22 patients. A total of 97.6% of the patients tolerated the tests. Of the 202 tolerated tests, 130 were performed on 16 patients who had their device explanted due to myocardial recovery (recovered group), and 72 on 6 patients who did not recover and were transplanted (non-recovered group). After device discontinuation there was an immediate drop in mean arterial blood pressure (MAP), a rise in HR, a reduction in EF and increases in ventricular dimensions. These changes tended to be more marked in the non-recovered group. After 6MW, the recovered group had a significant rise in HR and EF and a non-significant increase in MAP, whereas, the non-recovered group there was a significant drop in MAP compensated by a rise in HR. The distance walked in the recovered group was significantly higher (544 +/- 102 vs 418 +/- 109 meters, p < 0.05). MAP, pulse pressure and EF were strong predictive factors for recovery. CONCLUSIONS: Acute discontinuation of the device to assess recovery is safe and well tolerated and is followed by specific changes in hemodynamic and echocardiographic parameters. This helps in the assessment of recovery, particularly with regard to findings taken after exercise.