Direct observation and modelling of embolism spread between xylem conduits: a case study in Scots pine

Xylem embolism is one of the main processes involved in drought-related plant mortality. Although its consequences for plant physiology are already well described, embolism formation and spread are poorly evaluated and modelled, especially for tracheid-based species. The aim of this study was to assess the embolism formation and spread in Pinus sylvestris as a case study using X-ray microtomography and hydraulics methods. We also evaluated the potential effects of cavitation fatigue on vulnerability to embolism and the micro-morphology of the bordered pits using scanning electron microscopy (SEM) to test for possible links between xylem anatomy and embolism spread. Finally, a novel model was developed to simulate the spread of embolism in a 2D anisotropic cellular structure. Results showed a large variability in the formation and spread of embolism within a ring despite no differences being observed in intertracheid pit membrane anatomical traits. Simulations from the model showed a highly anisotropic tracheid-to-tracheid embolism spreading pattern, which confirms the major role of tracheid-to-tracheid air seeding to explain how embolism spreads in Scots pine. The results also showed that prior embolism removal from the samples reduced the resistance to embolism of the xylem and could result in overestimates of vulnerability to embolism.

[Application of Mimics three-dimensional imaging in percutaneous left atrial appendage closure with Watchman system]

OBJECTIVE

The three-dimensional (3D) structure of left atrial appendage (LAA) in atrial fibrillation patients were reconstructed by Mimics 3D imaging system, aiming at guiding for selection of both the size and location of the closure devices and making preliminary risk assessment of LAA closure with Watchman system.

METHODS

Inclusion criteria were: ten voluntary patients with both atrial fibrillation and indication for LAA closure aging from 40 to 85 years old with contraindication for oral anticoagulants or unwillingness to take long-term oral anticoagulation therapy from May to December 2014. 3D reconstruction of LAA was preoperatively made by Mimics 3D imaging system. With the Mimics 3D reconstruction model and the results of both transesophageal echocardiography (TEE) and LAA radiography, the size and location for the closure device were chosen. The devices were planted at the ostium of the LAA.

RESULTS

Ten atrial fibrillation patients were enrolled (average age: (66.3±11.9) years old) and all successfully implanted with the Watchman LAA closure devices. Nine of them were with non-valvular atrial fibrillation with average CHADS2-VAS score (3.2±1.7) and HAS-BLED score (2.7±1.6). The rest one was a valvular atrial fibrillation patient with the history of the percutaneous balloon mitral valvuloplasty (PBMV) without surgical indications of mitral valve replacement (MVR). There was no blood leakage around the device by regular postoperative TEE and LAA radiography examinations. There were no complications of bleeding, embolism, or stroke through both at peri-operative period and at 1 month follow-up post procedure.

CONCLUSION

Preoperative Mimics 3D reconstruction of LAA by Mimics 3D imaging system among atrial fibrillation patients provides essential information guiding the successful LAA closures.

Symmetrical directional dual-tree complex wavelet packet transform

In this study, a symmetrical directional complex discrete wavelet packet transform, which can be applied directly to the quadrature format signals and has the ability of mapping directional information during decomposition stage, is proposed. With the proposed symmetrical directional complex wavelet packet transform, traditional symmetrical phasing filter technique, which is used for quadrature signal to directional signal conversion, is eliminated and the computational complexity of whole process is reduced. The performance of proposed method is examined in detail using real quadrature embolic signals.

Safety assessment of intraportal liver cell application in New Zealand white rabbits under GLP conditions

Liver cell transplantation (LCT) is considered a new therapeutic strategy for the treatment of acute liver failure and inborn metabolic defects of the liver. Although minimally invasive, known safety risks of the method include portal vein thrombosis and pulmonary embolism. Since no systematic data on these potential side effects exist, we investigated the toxicological profile of repeated intraportal infusion of allogeneic liver cells in 30 rabbits under GLP conditions. Rabbit liver cells were administered once daily for 6 consecutive days at 3 different dose levels, followed by a 2-week recovery period. No test item-related mortality was observed. During cell infusion, clinical findings such as signs of apathy and hyperventilation, moderate elevations of liver enzymes ALT and AST and a slight decrease in AP were observed, all fully reversible. Cell therapy-related macroscopic and histological findings, especially in liver and lungs, were observed in animals of all dose groups. In conclusion, the liver and lungs were identified as potential toxicological target organs of intraportal allogeneic liver cell infusion. A NOAEL (no observed adverse effect level) was not defined because of findings observed also in the low-dose group. No unexpected reactions became apparent in this GLP study. Overall, LCT at total doses up to 12 % (2 % daily over 6 days) of the total liver cell count were tolerated in rabbits. Observed adverse effects are not considered critical for treatment in the intended patient populations provided that a thorough monitoring of safety relevant parameters is in place during the application procedure.

[Maternal mortality in Japan and cardiopulmonary resuscitation in pregnancy]

Maternal mortality rate in Japan decreased dramatically in the last 50 years. It reached 3.2, one of the lowest in the world. Currently the main causes of maternal death in Japan are hemorrhage, obstetric embolism and pregnancy induced hypertension. Several modifications to standard cardiopulmonary resuscitation are needed for pregnant women. Uterine displacement, deeper chest compressions, and early tracheal intubation are essential. Emergency cesarean delivery should be considered as soon as a pregnant woman develops cardiac arrest.

Lemierre syndrome: a case of postanginal sepsis

Lemierre syndrome is a rare disease that's characterized by internal jugular vein thrombosis and septic emboli. These symptoms typically develop after acute oropharyngeal infection by Fusobacterium necrophorum. Although this syndrome is less frequently seen in modern times due to the availability of antibiotics, physicians must be aware of the syndrome in order to initiate prompt antibiotics therapy, including coverage of the anerobic organisms. We discuss here the case of an 18-year-old female with Lemierre syndrome and we review the relevant literature on this syndrome.