Low-frequency pulsed electromagnetic field pretreated bone marrow-derived mesenchymal stem cells promote the regeneration of crush-injured rat mental nerve

Bone marrow-derived mesenchymal stem cells （BMSCs） have been shown to promote the regeneration of injured peripheral nerves. Pulsed electromagnetic field （PEMF） reportedly promotes the proliferation and neuronal differentiation of BMSCs. Low-frequency PEMF can induce the neuronal differentiation of BMSCs in the absence of nerve growth factors. This study was designed to investigate the effects of low-frequency PEMF pretreatment on the proliferation and function of BMSCs and the effects of low-frequency PEMF pre-treated BMSCs on the regeneration of injured peripheral nerve using in vitro and in vivo experiments.In in vitro experiments, quantitative DNA analysis was performed to determine the proliferation of BMSCs, and reverse transcription-polymerase chain reaction was performed to detect S100 （Schwann cell marker）, glial fibrillary acidic protein （astrocyte marker）, and brain-derived neurotrophic factor and nerve growth factor （neurotrophic factors） mRNA expression. In the in vivo experiments, rat models of crush-injured mental nerve established using clamp method were randomly injected with low-frequency PEMF pretreated BMSCs, unpretreated BMSCs or PBS at the injury site （1 × 106 cells）. DiI-labeled BMSCs injected at the injury site were counted under the fluorescence microscope to determine cell survival. One or two weeks after cell injection, functional recovery of the injured nerve was assessed using the sensory test with von Frey filaments. Two weeks after cell injection, axonal regeneration was evaluated using histomorphometric analysis and retrograde labeling of trigeminal ganglion neurons. In vitro experiment results revealed that low-frequency PEMF pretreated BMSCs proliferated faster and had greater mRNA expression of growth factors than unpretreated BMSCs. In vivo experiment results revealed that compared with injection of unpretreated BMSCs, injection of low-frequency PEMF pretreated BMSCs led to higher myelinated axon count and axon density and more DiI-labeled neurons in the trigeminal ganglia, contributing to rapider functional recovery of injured mental nerve. These findings suggest that low-frequency PEMF pretreatment is a promising approach to enhance the efficacy of cell therapy for peripheral nerve injury repair.

Hepatothorax due to a right diaphragmatic rupture related to duodenal ulcer perforation

Here, we present the case of a 53-year-old man with a hepatothorax due to a right diaphragmatic rupture related to duodenal ulcer perforation. On admission, the patient complained of severe acute abdominal pain, with physical examination findings suspicious for a perforated peptic ulcer. Of note, the patient had no history of other medical conditions or recent trauma, and the initial chest radiography and laboratory findings were not specific. A subsequent abdominal computed tomography revealed intrathoracic displacement of the liver, gallbladder, transverse colon and omentum through a right diaphragmatic defect. The patient then underwent an explorative laparotomy that confirmed duodenal ulcer perforation. A primary repair of the duodenal perforation was performed, and the diaphrag-matic defect was repaired using a polytetrafluoroeth-ylene patch after the organs were reduced and the cavity irrigated. This particular case proves interesting as right-sided spontaneous diaphragmatic ruptures are very rare and difficult to diagnose. Additionally, the best treatment for such large diaphragmatic defects is still controversial, especially in cases of intrathoracic or intra-abdominal contamination.