36 research outputs found
Implantable and Biodegradable Macroporous Iron Oxide Frameworks for Efficient Regeneration and Repair of Infracted Heart
The construction, characterization and surgical application of a multilayered iron oxide-based macroporous composite framework were reported in this study. The framework consisted of a highly porous iron oxide core, a gelatin-based hydrogel intermediary layer and a matrigel outer cover, which conferred a multitude of desirable properties including excellent biocompatibility, improved mechanical strength and controlled biodegradability. The large pore sizes and high extent of pore interconnectivity of the framework stimulated robust neovascularization and resulted in substantially better cell viability and proliferation as a result of improved transport efficiency for oxygen and nutrients. In addition, rat models with myocardial infraction showed sustained heart tissue regeneration over the infract region and significant improvement of cardiac functions following the surgical implantation of the framework. These results demonstrated that the current framework might hold great potential for cardiac repair in patients with myocardial infraction
Effects of Post-Weld Heat Treatment on the Microstructure and Mechanical Properties of Automatic Laser-Arc Hybrid Welded AZ31B Magnesium Alloys
The aim of this study was to determine the microstructural evolution, tensile characteristics, and strain-hardening response of AZ31B magnesium alloy welds as influenced by post-weld heat treatment (PWHT). Thus, the AZ31B alloy was welded by using a low-power pulsed Nd:YAG laser-arc hybrid welding equipped on the six-axis welding robot in the present study. Microstructure, mechanical properties and strain-hardening behaviors of the AZ31B joints under various post-weld heat treatment (PWHT) temperatures were characterized. As the heat treatment temperature increases, the grain size of the welded joint gradually increases, and the amount of β-Mg17AI12 phase noticeably decreases. The mechanical properties of the welded joint specimens showed a significant enhancement when subjected to heat treatment at 300 °C and 350 °C for 20 min. Especially, after 350 °C heat treatment for 20 min, the ultimate tensile strength (UTS) and elongation (EL) of specimen were 339.6 MPa and 20.1%, respectively, which were up to 99.5% and 98.5% of the AZ31B base material (BM). The strain-hardening capacity of specimens is significantly influenced by the grain size. Due to having the largest grain size, the 400–20 min specimen exhibited the highest hardening capacity and strain hardening exponent. In Kocks-Mecking type curves, both stage III and stage IV were observed in BM and joint specimens. At higher net flow stresses, the strain hardening rate in the 400–20 min joint specimen was higher due to the larger grains, which allowed for more dislocation accommodation and improved the capacity for dislocation storage
Comprehensive RNA-Seq profiling of the lung transcriptome of Bashbay sheep in response to experimental Mycoplasma ovipneumoniae infection.
The Bashbay sheep (Ovis aries), an indigenous breed of Xinjiang, China, has many excellent characteristics. It is resistant to Mycoplasma ovipneumoniae infection, the causative agent of mycoplasma ovipneumonia, a chronic respiratory disease that is harmful to the sheep industry. To date, knowledge regarding the mechanisms responsible for M. ovipneumoniae pathogenesis in scant. Herein, we report the results of transcriptome profiling of lung tissues from Bashbay sheep experimentally infected with an M. ovipneumoniae strain at 4 and 14 days post-infection, in comparison to mock-infected animals (0 d). Transcriptome profiling was performed by deep RNA sequencing, using the Illumina platform. The analysis of differentially expressed genes was performed to determine concomitant gene-specific temporal patterns of mRNA expression in the lungs after M. ovipneumoniae infection. We found 1048 differentially expressed genes (575 up-regulated, 473 down-regulated) when comparing transcriptomic data at 4 and 0 days post-infection, and 2823 (1362 up-regulated, 1461 down-regulated) when comparing 14 versus 0 days post-infection. Kyoto Encyclopedia of Genes and Genomes pathway analysis showed that the differentially expressed genes at 4 and 14 versus 0 days post-infection were enriched in 245 and 287 pathways, respectively, and the Toll-like receptor (TLR) signaling pathway was considered most closely related to MO infection (p < 0.01). Two pathways (LAMP-TLR2/TLR6-MyD88-MKK6-AP1-IL1B and LAMP-TLR8MyD88-IRF5-RANTES) were identified based on the TLR signaling pathway from differentially expressed genes related M. ovipneumoniae infection. Gene Ontology analysis showed that differentially expressed genes in different groups were enriched for 1580 and 4561 terms, where those most closely related to M. ovipneumoniae infection are positive regulators of inflammatory responses (p < 0.01). These results could aid in understanding how M. ovipneumoniae infection progresses in the lungs and may provide useful information regarding key regulatory pathways
A Single-Pass Type I Membrane Protein from the Apicomplexan Parasite Cryptosporidium parvum with Nanomolar Binding Affinity to Host Cell Surface
Cryptosporidium parvum is a globally recognized zoonotic parasite of medical and veterinary importance. This parasite mainly infects intestinal epithelial cells and causes mild to severe watery diarrhea that could be deadly in patients with weakened or defect immunity. However, its molecular interactions with hosts and pathogenesis, an important part in adaptation of parasitic lifestyle, remain poorly understood. Here we report the identification and characterization of a C. parvum T-cell immunomodulatory protein homolog (CpTIPH). CpTIPH is a 901-aa single-pass type I membrane protein encoded by cgd5_830 gene that also contains a short Vibrio, Colwellia, Bradyrhizobium and Shewanella (VCBS) repeat and relatively long integrin alpha (ITGA) N-terminus domain. Immunofluorescence assay confirmed the location of CpTIPH on the cell surface of C. parvum sporozoites. In congruence with the presence of VCBS repeat and ITGA domain, CpTIPH displayed high, nanomolar binding affinity to host cell surface (i.e., Kd(App) at 16.2 to 44.7 nM on fixed HCT-8 and CHO-K1 cells, respectively). The involvement of CpTIPH in the parasite invasion is partly supported by experiments showing that an anti-CpTIPH antibody could partially block the invasion of C. parvum sporozoites into host cells. These observations provide a strong basis for further investigation of the roles of CpTIPH in parasite-host cell interactions
The Vigabatrin Induced Retinal Toxicity is Associated with Photopic Exposure and Taurine Deficiency: An In Vivo Study
Background/Aims: Retinal toxicity is one of the most commonly discussed and concerning adverse effects of vigabatrin (VGB). The present study explored the relationship between the VGB elicited retinal toxicity, photopic exposure, and taurine deficiency, aiming at screening for risk factors to minimize the adverse effects of VGB. Methods: The effects of VGB on function and morphology of mouse retinas were examined via a series of in vivo tests, including electroretinography (ERG), Spectral domain optical coherence tomography (SD-OCT), and optokinetic testing. Moreover, VGB-treated mice were in addition treated with taurine to verify possible protective effects against retinal toxicity. Results: A close relationship between VGB induced retinal toxicity and light exposure was observed. The VGB-treated mice which were reared in darkness preserved better visual function and retinal architectures as verified by the optokinetic tests, OCT and ERG examinations. The retinal taurine level of the VBG-treated mice which were exposed to light were significantly lower than that of the VBG mice reared in darkness. Furthermore, several in vivo evidence provided by our research confirmed that the VGB induced morphological and functional impairments could be partially alleviated by taurine treatment. The present study showed the retinal toxicity of VGB by in vivo measurements. Conclusion: The VGB induced retinal toxicity is closely associated with photopic exposure and taurine deficiency. Patients who are taking VGB might benefit from minimization of light exposure and dietetic taurine supplements
Distinct Clinical Characteristics of Pediatric Guillain-Barré Syndrome: A Comparative Study between Children and Adults in Northeast China.
OBJECTIVE:Clinical characteristics of pediatric Guillain-Barré syndrome (GBS) have been extensively studied whereas scarcely been compared with those of adult GBS. Herein we compared the clinical features of GBS between pediatric and adult patients. METHODS:We retrospectively collected the clinical data of 750 patients with GBS (541 adults and 209 children), and compared the clinical characteristics between children and adults. RESULTS:Pain was a more frequent complaint in children (17.2% vs 9.6%, p 0.05). The clinical features of acute motor axonal neuropathy (AMAN) and acute inflammatory demyelinating polyneuropathy (AIDP) in children were overall comparable with adult ones (p > 0.05). Similar to adults, bulbar dysfunction (odds ratio [OR]: 4.621, 95% confidence interval [CI]: 1.240-17.218, p < 0.05) and lower nadir Medical Research Council (MRC) sum score (OR: 0.897, 95% CI: 0.855-0.941, p < 0.01) were also risk factors for mechanical ventilation in children. However, distinct from adult ones, autonomic dysfunction was significantly higher in mechanically ventilated childhood GBS (39.1% vs 8.8%, p < 0.01), which also served as a predictor for mechanical ventilation in pediatric GBS (OR: 70.415, 95% CI: 9.265-535.158, p < 0.01). As to the efficacy of intravenous immunoglobulin, insignificant difference was identified between children and adults. CONCLUSION:The clinical features of pediatric GBS differ from those of adults. Autonomic dysfunction is an independent risk factor for mechanical ventilation in pediatric patients