Certain types of enteroviruses, including coxsackieviruses, cause encephalitis, and other neurological complications. However, these pathogens rarely cause fatal infections, especially in ...immunocompetent infants. In this study, we present a rare case of acute encephalopathy caused by coxsackievirus A2 (CV-A2), which progressed rapidly in a previously healthy female child. Based on our findings, we concluded that a previously healthy girl who had no immediate history of underlying medical condition were susceptible to death by acute encephalopathy due to CV-A2 infections. We proposed this conclusion because the patient's condition progressed rapidly in less than 2 h and eventually led to her death. This is the first report on an acute encephalitis-dependent death in a child due to CV-A2 infection.
Nanoindentation creep tests were performed at the grain boundary and grain interior in pure magnesium. The grain boundary showed a high strain rate sensitivity exponent and was dominated by grain ...boundary sliding due to the high diffusion rate at the grain boundary. The grain boundary affected the deformation behavior of the area at a distance of 2 µm into the grain interior. On the other hand, the grain interior had a low strain rate sensitivity exponent, because its matrix was too large to be influenced by the grain boundary. The deformation mechanism in the grain interior was determined to be dislocation slip.
Here the pathophysiology of venous thromboembolism is reviewed with respect to the anatomical features of the deep veins of lower limbs. A thrombus is less likely to form in the thigh veins compared ...with that in the calf veins; however, clinical symptoms are more likely to appear in the thigh veins owing to vascular occlusion. When a patient is bedridden, thrombosis is more likely to occur in the intramuscular vein, which mainly depends on muscular pumping and the venous valve, rather than in the three crural branches, which mainly depends on the pulsation of the accompanying artery. Thrombi are prone to be generated in the soleal vein compared with those in the gastrocnemius vein because of the vein and muscle structures. A soleal vein thrombosis grows toward the proximal veins along the drainage veins. To prevent a sudden pulmonary thromboembolism-related death in bedridden patients, preventing soleal vein thrombus formation and observing the thrombus proximal propagation via the drainage veins are clinically important. When deep vein thrombosis occurs, avoiding embolization and sequela caused by the thrombus organization is necessary.
High-temperature compressive properties at a high strain rate of 10
3 s
−1 were examined in solution treated AZ91 magnesium alloy. Analysis of the flow behavior and microstructural observations ...indicated that the deformation at high strain rates of ∼10
3 s
−1 proceeds by conventional plastic flow of dislocation glide and twinning even at elevated temperatures.
The fracture toughness of an extruded Mg–2.6
at.% Zn–0.4
at.% Y alloy with a grain size of 1
μm and containing quasicrystalline icosahedral phase was determined to be 32.5
MPa
m
1/2, which is much ...higher than conventional wrought magnesium alloys. Microstructural observations showed that the quasicrystalline phase pinned many dislocation movements and prevented void nucleation because of its coherent interface with the matrix.
The friction and wear properties of pure magnesium and the Mg–Y alloy were investigated using the pin-on-disk configuration. The friction and wear resistance of the Mg–Y alloy was superior to those ...of pure magnesium. The wear mechanism was abrasion under all the conditions. The deformed microstructural evolutions near the surface region were observed by transmission electron microscopy and electron backscatter diffraction. The stress and strain states were also evaluated by finite element analysis (FEA). The deformed microstructures of both alloys consisted of the {10–12} twinning formation and the FEA results showed the occurrence of plastic deformation even at the beginning of the test. The formation of low angle grain boundaries was also confirmed with an increase in the applied load in the Mg–Y alloy. On the other hand, grain refinement due to dynamic recrystallization was observed in pure magnesium as the wear test progressed. The different microstructures resulted from difference in the surface temperature during the wear test, which was estimated to be around 393K and 363K for pure magnesium and the Mg–Y alloy, respectively. The high increment temperature in the fine-grained alloys brought about the occurrence of grain boundary sliding, i.e., material softening, which led to a decrease in the friction and wear properties. The present results indicated that one of the methods for enhancing the friction and wear properties is to increase the dynamic recrystallization temperature.
•Mitochondrial dysfunction might be responsible for the PQ-provoked toxicity.•An accumulation ability of PINK1 by PQ is different between A549 and BEAS.•A549 that are resistant to oxidative stress ...were more susceptible to PQ than BEAS.•PQ concentration in A549 after exposure was higher than that in BEAS.•The amount of ROS generated in A549 after PQ exposure was as low as that in BEAS.
Paraquat (PQ) is one of the commonly used herbicides in the world, despite its high toxicity. The ingestion of PQ accidentally or intentionally causes severe damage in diverse organs including the lung. Pulmonary fibrosis triggered by PQ accumulation in the lung epithelial cells is one of the major causes of death. This study investigated the intracellular accumulation of PQ, reactive oxygen species (ROS) generation and mitochondrial injury using two lung epithelial cell lines A549 and BEAS-2B (BEAS). Although A549 exhibit greater resistance to oxidative stress than BEAS, a cytotoxicity assay for PQ demonstrated that EC50 for lethality in A549 was 7 times lower than that in BEAS. When exposed to PQ at a concentration around EC50 for lethality, the amount of ROS generated in A549 was as low as that in BEAS. Conversely, the cellular concentration of PQ in A549 after exposure was higher than that in BEAS, which suggests a distinct difference in the susceptibility to PQ between these cell lines. After a 16 h exposure to PQ, mitochondrial membrane potential (MMP) decreased in A549, but decreased only slightly in BEAS even following a 30 h exposure. PQ-exposed A549 reduced an accumulation of PTEN-induced kinase 1 (PINK1), which works in degradation of damaged mitochondria, following the decrease of MMP, whereas PQ did not decline the PINK1 in BEAS. These results suggest that mitochondrial dysfunction due to cellular accumulation of PQ might contribute to the PQ-provoked toxicity more than the ROS generation in the lung epithelial cells.
Objective:
In this study, autologous bone grafts using bone-fixing nails made of magnesium-zinc-calcium ternary alloys were performed using rabbit skulls.
Material and methods:
Two types of nails for ...bone fixation were prepared: 2.5 mm width, 3 mm length and 2.5 mm width, 2 mm length. A disk-shaped bone with a diameter of 5 mm was resected from the parietal bone and fixed with a 3 mm long nail. As a control group, a 2 mm long nail was driven into the existing bone. The rabbits were sacrificed at 1, 4, 12, and 24 weeks after surgery. The resected samples were observed with micro X-ray CT, and embedded in methyl methacrylate to prepare non-decalcified specimens. The in vivo localization of elements was examined using energy-dispersive X-ray spectroscopy (EDS).
Results:
Micro X-ray CT images of samples showed volume reduction due to degradation in both the bone graft and control groups. No significant difference in the amount of degradation between the two groups was observed, however characteristic degradation processes were observed in each group. The samples stained with alizarin red S showed amorphous areas around the nails, which were considered as corrosion products and contacted directly with the newly formed bones. EDS analysis showed that corrosion products were mainly composed of magnesium and oxygen at an early stage, while calcium and phosphorus were detected on the surface layer during the long-term observation.
Conclusions:
The degradation speed of the magnesium alloy nails varied depending on the shapes of the nails and surrounding tissue conditions. A calcium phosphate layer was formed on the surface of magnesium alloy nails, suggesting that the degradation rate of the nail was slow.
Purpose
Metallic medical devices are typically constructed from non-bioabsorbable metals that remains in the body and causes considerable complications. Particularly in the urinary tract, calculus, ...intractable infection, and misdiagnosis as calculus are often caused by non-bioabsorbable metals. Here, we developed a zinc–magnesium alloy as a new bioabsorbable metal and sought to evaluate the bioabsorbable behavior of zinc and zinc–magnesium alloy in a rat bladder implantation model.
Methods
We prepared zinc–magnesium alloy wires with various proportions of magnesium and investigated the strength, shape retention, formability, and absorbability of these novel materials. Then, we implanted zinc and zinc–magnesium alloy rings formed by the wires into rat bladder. Rats were euthanized at the end of the observation period, and the rings were removed for volume evaluation. Extracted bladder tissues were subjected to histological analysis.
Results
The strength of the zinc wire was enhanced by more than fourfold upon the addition of magnesium, without loss of ductility. Linear reduction of ring volume in urine was observed based on the concentration of magnesium within the ring. Nearly all rings were covered with a thin layer of calculus. Histological findings of the transected urinary bladder tissues did not differ among groups.
Conclusions
Zinc–magnesium alloy is a promising candidate for use as a bioabsorbable medical device in the urinary tract.
PDF
