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Inspired by mussel chemistry, adhesive hydrogels represented by polydopamine (PDA) have been widely studied in many fields such as biomedical applications and bioelectronics. However, the process of producing PDA from dopamine often requires specific conditions, which oxidize some of the effective groups and reduce the adhesion effect. So it is important to develop a simple and effective method for fabrication and application of adhesive hydrogels. In this work, an adhesive hydrogel composed of xylan, polyacrylic acid (PAA) and tannic acid (TA) was developed using a facile approach, which exhibited excellent mechanical and adhesion properties. The xylan and TA both from plants could endow the hydrogels with unique properties such as biocompatibility and biodegradability. Surprisingly, the resultant hydrogels exhibited excellent stretchability (extension ratio up to 4600%) and adhesive strength (up to 25 kPa). Besides, the synthesized hydrogels displayed excellent antioxidant and antibacterial properties, while the scavenging rate of 2, 2-Diphenyl-1-picrylhydrazyl (DPPH) radical reached to 94.12%. This study provides a new insight for the design of hydrogels with stretchable, adhesive, antioxidant and antibacterial abilities.

A xylan-based antimicrobial additive agent was prepared and studied for use in paper products against Escherichia coli bacteria. The derived cationic-xylan-grafted-guanidine polymer (CX-g-PHGH) was successfully synthesized by graft copolymerization of cationic-xylan with polyhexa-methylene guanidine hydrochloride (PHGH) using ceric ammonium nitrate as an initiator. The obtained CX-g-PHGH had a maximum PHGH grafting ratio of 18.4% and efficiency of 58.4% and showed good viscosity and thermal stability. Furthermore, the paper samples prepared in this work were reinforced noticeably with the addition of CX-g-PHGH, after which exhibited improved mechanical properties. Compared to the reference paper without any of the xylan derivatives, the index of tensile, tear, burst, and folding endurance of the paper were increased by up to 20.1%, 25.3%, 30.2%, and 77.8%, respectively. Moreover, the prepared CX-g-PHGH paper exhibited efficient antimicrobial barrier properties against E. coli bacteria, by which many applications based on the new xylan derived additive agent obtained in this work could be found, especially in field of antimicrobial paper products against E. coli bacteria from contaminated food.

Human umbilical cord mesenchymal stem cell (hucMSC) derived exosomes (EXOs) have been investigated as a new treatment for spinal cord injury (SCI) because of their anti-inflammatory, anti-apoptotic, angiogenesis-promoting, and axonal regeneration properties. The CAQK peptide found in the brains of mice and humans after trauma has recently been found to specifically bind to the injured site after SCI. Thus, we developed a nanocarrier system called EXO-C@P based on hucMSC exosomes remodelled by the CRISPR/Cas9 plasmid to control inflammation and modified by the CAQK peptide. EXO-C@P was shown to effectively accumulate at the injury site and saturate the macrophages to significantly reduce the expression of inflammatory cytokines in a mouse model of SCI. Moreover, EXO-C@P treatment improved the performance of mice in behavioural assessments and upregulated soluble tumour necrosis factor receptor-1 (sTNFR1) in serum and at the trauma site after SCI surgery, but lowered the proportion of iNOS

Background. Tuina, acupuncture, traction, and Chinese herbs play an important role in the treatment of lumbar disc herniation. However, the comparative effectiveness and safety of the four commonly utilized treatment modalities are still unclear. Objective. To compare the effectiveness and safety of the four interventions for lumbar disc herniation. Methods. Randomized controlled trials comparing any two of the four interventions in the treatment of lumbar disc herniation were identified using the following databases: PubMed, the Cochrane Library, Embase, Web of Science, the China National Knowledge Infrastructure, Chinese Science and Technology Periodical Database, and Wanfang data, and network meta-analysis was performed using STATA 14.0. Results. One hundred and twenty-one studies involving a total of 13075 patients were included. In all the outcome measurements, traction demonstrated a worst effectiveness, and Tuina and acupuncture demonstrated a best effectiveness, but no significant differences were found between Tuina and acupuncture. Compared with Tuina or acupuncture, Chinese herbs showed a similar effectiveness in Visual Analogue Score and Japanese Orthopedic Association Scores, but an inferior effectiveness in invalid rate and cure rate. Conclusions. In the treatment of lumbar disc herniation, Tuina and acupuncture were superior to traction or Chinese herbs, and the effectiveness of traction was the worst. However, considering the limitations of this review, more high-quality trials, especially those comparing Chinese herbs with the other three interventions, should be carried out in the future to further confirm the current findings.

Objective: To investigate the biomechanical effects of osteoporosis on adjacent segments after posterior lumbar interbody fusion (PLIF). Methods: This study was designed and conducted in the Traumatology and Orthopedics Laboratory, School of Chinese Medicine, Jinan University, Guangzhou, China, between December 2019 and February 2020. A healthy finite element model of L3-S1 was developed along with one PLIF model and one PLIF with osteoporosis model. Based on a hybrid test method, the inferior surface of S1 was entirely fixed, and a preload of 400N combined with an adjusted moment was imposed on the superior surface of L3 in each model to simulate flexion, extension, lateral bending and axial rotation. The intradiscal pressure (IDP), shear stress on annulus fibrosus, and the range of motion (ROM) of L3-L4 and L5-S1 were calculated and compared. Results: In each direction, the highest value of IDP and shear stress on annulus fibrosus at L3-L4 and L5-S1 was found in the PLIF model, and the lowest value in the healthy model. The largest ROM at L4-L5 appeared in the healthy model, and the smallest value in the PLIF model in each direction. At L3-L4 and L5-S1, the highest ROM in most directions was found in the PLIF model, followed by the PLIF with osteoporosis model, and the lowest value in the healthy model. Conclusions: Osteoporosis can decrease IDP, shear stress on annulus fibrosus, and ROM at adjacent levels, and slow down the development of ASD after PLIF. doi: https://doi.org/10.12669/pjms.37.2.3223 How to cite this:Zhang C, Chang M, Zhang R, Tang S. Biomechanical effects of osteoporosis on adjacent segments after posterior lumbar interbody fusion: A finite element study. Pak J Med Sci. 2021;37(2):403-408. doi: https://doi.org/10.12669/pjms.37.2.3223 This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Background Immune cell infiltration and neuroinflammation are heavily associated with spinal cord injury (SCI). C-C motif chemokine ligand 2/C-C chemokine receptor type 2 (CCL2/CCR2) axis has been identified as a critical role player during the invasion of immune cells to lesions in many diseases. γδ T cells, a subgroup of T cells, manage the course of inflammation response in various diseases; however, it remains unknown whether γδ T cells are recruited to injury site through CCL2/CCR2 signaling and exert the regulation effect on neuroinflammation after SCI. Methods Basso Mouse Scale (BMS), regularity index, cadence, max contact area, and motor-evoked potential testing (MEP) were measured to determine the neurological function recovery after spinal cord injury. Nissl staining was performed to identify the number of surviving motor neurons at lesion epicenter. Immunofluorescence, Western blot, enzyme-linked immunosorbent assays (ELISA), and quantitative real-time polymerase chain reaction (QRT-PCR) also were employed to evaluate the expression of associated proteins and genes. Results In this study, we demonstrated that TCRδ−/− mice present improved neurological recovery after SCI. γδ T cell recruitment to the SCI site was significantly reduced and motor functional improvement enhanced in CCL2−/− and CCR2−/− mouse strains. Furthermore, reconstitution of TCRδ−/− mice with γδ T cells extracted from CCR2−/− mice also showed similar results to CCL2 and CCR2 deficient mice. Conclusions In conclusion, γδ T cell recruitment to SCI site promotes inflammatory response and exacerbates neurological impairment. CCL2/CCR2 signaling is a vital recruitment mechanism of γδ T cells to the SCI site, and it may be taken as a novel therapeutic target for future SCI.

Objective To compare the effectiveness of exercise therapy with surgery for lumbar spinal stenosis. Methods Five English databases PubMed, the Cochrane Library, Web of science, OVID and PEDro database were searched for randomized controlled trials comparing surgical procedures with exercise therapy for lumbar spinal stenosis. Information on patients, study design, inclusion criteria, intervention and follow-up, outcomes, treatment details and adverse events were extracted. Meta-analysis was performed using Review Manager Version 5.3. Results Two randomized controlled trials and one mixed design trial with a total of 897 patients were included. The pooled results showed a significant difference between exercise and surgery in Oswestry Disability Index at two years (MD= 3.85, 95%CI: 0.48 to 7.22; P=0.03), but no significant difference at six months (MD= 2.18, 95%CI: -2.80 to 7.17; P=0.39) and one year (MD= 4.26, 95%CI: -1.79 to 10.32; P=0.17). In terms of physical function of 36 Items Short Form Health Survey, there were no significant differences between exercise and surgery at six months (MD= -2.23, 95% CI: -7.46 to 2.99; P=0.40), one year (MD= -2.17, 95% CI: -7.44 to 3.10; P=0.42) and two years (MD= -0.67, 95% CI: -6.16 to 4.82; P=0.81). Conclusion In brief, the current evidence demonstrated a trend that exercise therapy had a similar effect for lumbar spinal stenosis compared with decompressive laminectomies. However, for the small sample size and low methodology quality of the included trials, some rigorously designed and large-scaled RCTs need to be performed to confirm the conclusion.

Xylan-g-/P(AA-co-AM)/Graphene oxide (GO) hydrogels were prepared and used in the removal of heavy mental ions. Acrylamide (AM), acrylic acid (AA), and xylan were used as the raw materials to prepare the hydrogels with ammonium persulfate (APS) as the initiator. The prepared hydrogels were characterized by Fourier transform infrared (FTIR), thermogravimetric analysis (TGA), and energy dispersive X-ray (EDX). Some important properties of nanocomposite hydrogels such as swelling behavior, mechanical property, and adsorption capacity were also examined as well as the regeneration of the hydrogels. The results showed that the prepared hydrogels reached the equilibrium state of swelling after 12 h, and the compressive strength of the hydrogel with 30 mg of GO could reach up to 203 kPa. Compared with traditional hydrogel, the mechanical properties of the hydrogels with GO were obviously improved. The maximum adsorption capacity of hydrogels for Pb2+, Cd2+, and Zn2+ could reach up to 683 mg/g, 281 mg/g, and 135 mg/g, respectively. After five cycles of adsorption and desorption, the recovery rate of the hydrogels on Pb2+, Cd2+, and Zn2+ was still up to 87%, 80%, and 80%, respectively&mdash, all above 80%.

Xylan-g-/P(AA-co-AM)/Graphene oxide (GO) hydrogels were prepared and used in the removal of heavy mental ions. Acrylamide (AM), acrylic acid (AA), and xylan were used as the raw materials to prepare the hydrogels with ammonium persulfate (APS) as the initiator. The prepared hydrogels were characterized by Fourier transform infrared (FTIR), thermogravimetric analysis (TGA), and energy dispersive X-ray (EDX). Some important properties of nanocomposite hydrogels such as swelling behavior, mechanical property, and adsorption capacity were also examined as well as the regeneration of the hydrogels. The results showed that the prepared hydrogels reached the equilibrium state of swelling after 12 h, and the compressive strength of the hydrogel with 30 mg of GO could reach up to 203 kPa. Compared with traditional hydrogel, the mechanical properties of the hydrogels with GO were obviously improved. The maximum adsorption capacity of hydrogels for Pb2+, Cd2+, and Zn2+ could reach up to 683 mg/g, 281 mg/g, and 135 mg/g, respectively. After five cycles of adsorption and desorption, the recovery rate of the hydrogels on Pb2+, Cd2+, and Zn2+ was still up to 87%, 80%, and 80%, respectively—all above 80%.

Pore-forming agents have a significant influence on the pore structure of hydrogels. In this study, a porogenic technique was employed to investigate the preparation of macroporous hydrogels which were synthesized by radical copolymerization of carboxymethyl xylan with acrylamide and N-isopropylacrylamide under the function of a cross-linking agent. Six kinds of pore-forming agents were used: polyvinylpyrrolidone K30, polyethylene glycol 2000, carbamide, NaCl, CaCO3, and NaHCO3. The application of these hydrogels is also discussed. The results show that pore-forming agents had an important impact on the pore structure of the hydrogels and consequently affected properties of the hydrogels such as swelling ratio and mechanical strength, while little effect was noted on the thermal property of the hydrogels. 5-Fluorouracil was used as a model drug to study the drug release of the as-prepared hydrogels, and it was found that the drug release was substantially improved after using the NaHCO3 pore-forming agent: a cumulative release rate of up to 71.05% was achieved.

High strength hydrogels open new possibilities in the fields of bioengineering and biomedical. In this paper, a highly efficient one-pot strategy was developed to prepare carboxymethyl xylan-g-poly (acrylic acid) (CMX-g-PAA) hydrogels with high compression strength, high elongation and high elasticity by using the metal coordination and the reinforcement of hydroxylate multi-walled carbon nanotubes (HCNTs). Prepared hydrogels were characterized by means of FTIR, XRD, SEM, rheological measurements as well as their swelling and mechanical properties. Results showed that the Fe3+-carboxyl coordination and HCNTs imparted hydrogels with high strength and good rapid recovery properties, in which the maximum high compressive strength and elongation at break were achieved to 10.4 MPa and 1032%, and the shape of hydrogels almost returned to the original shape after the external force was removed after 30 cycles of compression. These hydrogels also exhibited Fe3+-triggered shape memory properties. Therefore, as-prepared hydrogels possessing high strength, rapid recovery and shape memory properties, could broaden access for application in intelligent toys, electronic skin, biosensing, and tissue engineering.

Introducing multifunctional groups and inorganic material imparts xylan-based hydrogels with excellent properties, such as responsiveness to pH, temperature, light, and external magnetic field. In this work, a composite hydrogel was synthesized by introducing acid treated carbon nanotubes (AT-CNTs) into the maleic anhydride modified xylan grafted with poly(N-isopropylacrylamide) (MAX-g-PNIPAM) hydrogels network. It was found that the addition of AT-CNTs affected the MAX-g-PNIPAM hydrogel structure, the swelling ratio and mechanical properties, and imparted the hydrogel with new properties of electrical conductivity and near infrared region (NIR) photothermal conversion. AT-CNTs could reinforce the mechanical properties of MAX-g-PNIPAM hydrogels, being up to 83 kPa for the compressive strength when the amount was 11 wt %, which was eight times than that of PNIPAM hydrogel and four times than that of MAX-g-PNIPAM hydrogel. The electroconductibility was enhanced by the increase of AT-CNTs amounts. Meanwhile, the composite hydrogel also exhibited multiple shape memory and NIR photothermal conversion properties, and water temperature was increased from 26 °C to 56 °C within 8 min under the NIR irradiation. Thus, the AT-CNTs reinforced MAX-g-PNIPAM hydrogel possessed promising multifunctional properties, which offered many potential applications in the fields of biosensors, thermal-arrest technology, and drug-controlled release.