Microbially influenced corrosion and rust tubercle formation on sheet piles in freshwater systems.

The extent of how complex natural microbial communities contribute to metal corrosion is still not fully resolved, especially not for freshwater environments. In order to elucidate the key processes, we investigated rust tubercles forming massively on sheet piles along the river Havel (Germany) applying a complementary set of techniques. In-situ microsensor profiling revealed steep gradients of O2 , redox potential and pH within the tubercle. Micro-computed tomography and scanning electron microscopy showed a multi-layered inner structure with chambers and channels and various organisms embedded in the mineral matrix. Using Mössbauer spectroscopy we identified typical corrosion products including electrically conductive iron (Fe) minerals. Determination of bacterial gene copy numbers and sequencing of 16S rRNA and 18S rRNA amplicons supported a densely populated tubercle matrix with a phylogenetically and metabolically diverse microbial community. Based on our results and previous models of physic(electro)chemical reactions, we propose here a comprehensive concept of tubercle formation highlighting the crucial reactions and microorganisms involved (such as phototrophs, fermenting bacteria, dissimilatory sulphate and Fe(III) reducers) in metal corrosion in freshwaters.

[Application of Intrabronchial Valves in High Risk Patients with Bronchopleural Fistula: an Alternative Therapeutic Option]. / Applikation intrabronchialer Ventile zur Behandlung der persistierenden bronchopleuralen Fistel nach komplikativem Pleuraempyem mit Lungendestruktion.

OBJECTIVES: Persistent air leak or bronchopleural fistula (BPF) is a challenging and frequently observed problem after pulmonary resection and may lead to prolonged chest tube therapy. One efficient nonsurgical approach to manage such a fistula is the application of intrabronchial valves. This may support earlier chest tube removal and hospital discharge. METHODS: Between 04/2015 and 03/2017, n = 8 patients (n = 4 female) with severe pleural empyema and necrotising lung tissue defects developed prolonged air leak and persistent BPF after surgery. Radiological and bronchoscopical investigations revealed the presence of a BPF. For closure, intrabronchial valves were endoscopically inserted into the affected bronchi. In patients with repeat development of empyema, a chest wall window was required (n = 6 patients). RESULTS: The mean age was 61 years (45 - 85 years). After repeated surgical debridement, the space was sterile and the chest wall window was closed. After valve placement, air leaks were no longer detectable. In all patients, the procedures were well tolerated without any negative events. After successful valve placement, chest tubes could be removed in all n = 8 patients within 7 days (3 - 15 days) and patients were discharged thereafter. CONCLUSIONS: Placement of intrabronchial valves presents an alternative option to conventional surgical and non-surgical methods for the treatment of postoperative persistent air leak or BPF. Particularly in high risk patients, this procedure is safe and effective.

Subcutaneous peripheral neurostimulation for the treatment of severe chronic poststernotomy neuralgia.

OBJECTIVE: Poststernotomy pain frequently develops after sternotomy in thoracic and cardiovascular surgery, and may affect patients' quality of life. In some cases of severe poststernotomy neuralgia, pharmacologic therapy does not provide adequate relief. CASE REPORT: We report on a 42- year-old woman who underwent sternotomy for aortic and mitral valve replacement. She developed severe chronic poststernotomy neuralgia that was refractory to medical treatment. After local anesthesia markedly but only transiently alleviated pain, we considered the option of subcutaneous peripheral neurostimulation (SPNS). Plate electrodes were implanted bilaterally in the parasternal region at the site of maximal pain. After a period of test stimulation, the electrodes were connected to a dual-channel implantable pulse generator. SPNS induced paresthesias in the painful area. Revision surgery was necessary twice because of electrode migration. Chronic SPNS markedly alleviated pain (visual-analog scale, VAS, 9/10 preoperatively, 2/10 postoperatively) and allodynia (VAS 9/10 preoperatively, 2/10 postoperatively) at the last available follow-up, 15 months postoperatively. CONCLUSIONS: SPNS may be a viable treatment option in patients with severe chronic poststernotomy neuralgia.

Glycine intravenous donor preconditioning is superior to glycine supplementation to low-potassium dextran flush preservation and improves graft function in a large animal lung transplantation model after 24 hours of cold ischemia.

OBJECTIVES: The potential role of glycine in combination with standard lung preservation with low-potassium dextran solution in lung ischemia-reperfusion injury has not been investigated in a preclinical porcine transplant model. METHODS: In a control group (n = 6), donor lungs were flushed with 1 liter of low-potassium dextran solution. In a second group (LPD-glyc, n = 6), low-potassium dextran solution was supplemented with 3.75 g of glycine. In a third group (IV-glyc, n = 6), donor preconditioning was performed by intravenous administration of 3.75 g glycine 1 hour before low-potassium dextran preservation. Grafts were stored in low-potassium dextran at 4 degrees C for 24 hours. Posttransplant graft function was assessed throughout a 7-hour observation period. RESULTS: In the control group, 2 recipients died of right-sided heart failure caused by severe ischemia-reperfusion injury. All animals of the glycine groups survived the entire observation period. Pulmonary vascular resistance remained significantly (P < .01) lower in both glycine groups when compared with controls. At the end of the observation period pulmonary vascular resistance in the control group was higher (P < .01) compared with the glycine groups (1310 +/- 319 dyn x sec x cm(-5) vs 879 +/- 127 dyn x sec x cm(-5) [LPD-glyc] vs 663 +/- 191 dyn x sec x cm(-5) [IV-glyc]). Changes of lung tissue water content were lower in the IV-glyc group compared with the LPD-control (P < .01) and LPD-glyc lungs (P < .05). Oxygenation (PO2/FiO2) was higher in the IV-glyc group compared with the LPD-glyc and control lungs (445 +/- 110 mm Hg vs 388 +/- 124 mm Hg [P < .01] vs 341 +/- 224 mm Hg [P < .001], respectively). DISCUSSION: Modification of low-potassium dextran solution with glycine or donor preconditioning ameliorates ischemia-reperfusion injury in lung transplantation. This intriguing approach merits further evaluation with respect to the mechanisms involved and may improve results in clinical lung preservation.

Glutathione improves the function of porcine pulmonary grafts stored for twenty-four hours in low-potassium dextran solution.

BACKGROUND: Flush perfusion with low-potassium dextran is the standard strategy in clinical lung preservation. Despite improved outcome, endothelial cell injury and surfactant dysfunction remain a significant problem after lung transplantation. The radical scavenger glutathione has been shown to be responsible for the efficacy of Celsior solution in lung preservation. We tested the hypothesis that the addition of glutathione to low-potassium dextran might further improve graft function by ameliorating ischemia-reperfusion injury. METHODS: In 12 domestic pigs, lungs were flush preserved with either low-potassium dextran (n = 6) or low-potassium dextran supplemented by 5 mmol glutathione (n = 6). Left single lung transplantation was performed after 24-hour storage in low-potassium dextran at 8 degrees C. After 15 minutes of reperfusion the right main bronchus and pulmonary artery were crossclamped. Hemodynamic and respiratory measures were recorded in 30-minute intervals for a total observation period of 7 hours. Bronchoalveolar lavage fluid was obtained from the native lung and 2 hours after reperfusion from the graft. Bronchoalveolar lavage fluid and surfactant composition, and surfactant function analyses were performed. Neutrophil sequestration was assessed by myeloperoxidase activity assay. Tissue water content was calculated from wet/dry weight ratios at the end of the experiment. RESULTS: In the low-potassium dextran group, 2 animals died during reperfusion. After reperfusion, pulmonary vascular resistance (P = .01) and pulmonary artery pressure remained lower in the glutathione/low-potassium dextran group, which was associated with a higher cardiac output (P = .05) in this group. Also, the oxygenation index at the end of the observation period was higher in the glutathione/low-potassium dextran group compared with the low-potassium dextran group (430 +/- 130 vs 338 +/- 184, respectively; P < .05). The graft water content representing postreperfusion lung edema was not different between the 2 study groups. Alteration of surfactant was less in the glutathione/low-potassium dextran group with a significantly decreased small to large aggregate ratio (P = .03) versus low-potassium dextran group. Myeloperoxidase activity was twice as high in the low-potassium dextran group when compared with the glutathione/low-potassium dextran group (glutathione/low-potassium dextran: 134 +/- 110 mU/g vs low-potassium dextran: 274 +/- 168 mU/g, P = .07). CONCLUSION: The addition of glutathione to low-potassium dextran preservation solution reveals beneficial effects on vascular function and surfactant composition in transplanted lungs. Therefore, glutathione ameliorates ischemia-reperfusion injury in a preclinical model of lung transplantation. Future studies are needed to evaluate this promising modification in clinical lung transplantation.

Melatonin acutely improves the neuroendocrine architecture of sleep in blind individuals.

In blind individuals, the absence of light cues results in disturbances of sleep and sleep-related neuroendocrine patterns. The Zeitgeber influence of light on the timing of sleep is assumed to be mediated by melatonin, a hormone of the pineal gland, whose secretion is inhibited by light and enhanced during darkness. Here, we investigated whether a single administration of melatonin improves sleep and associated neuroendocrine patterns in blind individuals. In a double-blind crossover study, 12 totally blind subjects received 5 mg melatonin and placebo orally 1 h before bedtime starting at 2300 h. The dose used enhanced blood melatonin concentrations to clearly supraphysiological levels. Melatonin increased total sleep time and sleep efficiency (P < 0.05, respectively) and reduced time awake (P < 0.05). The increment in total sleep time was primarily due to an increase in stage 2 sleep (P < 0.01) and a slight increase in rapid eye movement sleep (P < 0.06). Most important, melatonin normalized in parallel the temporal pattern of ACTH and cortisol plasma concentration. While after placebo, ACTH and cortisol levels did not differ between early and late sleep, melatonin induced the typical suppression of pituitary-adrenal activity during early sleep and a distinct rise during late sleep (P < 0.01, respectively). Cortisol nadir values were also decreased after melatonin (P < 0.05). We conclude from these data that in totally blind individuals the single administration of a clearly pharmacological dose of melatonin can improve sleep function by synchronizing in time the inhibition of pituitary-adrenal activity with central nervous sleep processes.