Enhanced His@AuNCs oxidase-like activity by reduced graphene oxide and its application for colorimetric and electrochemical detection of nitrite.

Enzyme-mimicking (nanozyme)-based biosensors are attractive owing to their unique catalytic efficiency, multifunctionality, and tunable activity, but examples of oxidase-like nanozymes are quite rare. Herein, we demonstrated that histidine-capped gold nanoclusters (His@AuNCs) possessed intrinsic oxidase-like activity, which could directly oxidize 3,3',5,5'-tetramethylbenzidine (TMB) to blue colored ox-TMB without H2O2. The assembly of reduced graphene oxide (RGO) with His@AuNCs could further improve its oxidase-like activity and the His@AuNCs/RGO nanocomposites had a lower Michaelis constant (Km) and higher catalytic constant (Kcat) for TMB oxidation. Furthermore, compared to other nanomaterials, the as-prepared His@AuNCs/RGO also exhibited enhanced electrocatalytic activity toward TMB. Interestingly, nitrite inhibited the catalytic (chromogenic) and electrocatalytic processes of His@AuNCs/RGO in the oxidation of TMB. The oxidase-like and electrocatalytic activity of His@AuNCs/RGO was evaluated with nitrite and TMB as substrates, and the results indicated that TMB and nitrite might share the same catalytic active sites. On the basis of these findings, a colorimetric and electrochemical sensor was developed with the His@AuNCs/RGO composite as an oxidase mimic for determination of nitrite with linear ranges of 10-500 µM and 2.5-5700 µM, respectively. The developed method was successfully applied to the detection of nitrites in real samples. The present work suggests that the oxidase-like nanozyme is not only suitable for colorimetric assay but also for development of electrochemical sensors in bioanalysis. Graphical abstract The colorimetric and electrochemical detection of nitrite using His@AuNCs/RGO.

[Treatment of ureaplasma urealyticum infection patients of Qi deficiency blood stasis syndrome by pengyan pill: a clinical observation].

OBJECTIVE: To observe the clinical efficacy of penyan pill (PP) in treating ureaplasma urealyticum (UU) infection patients of qi deficiency blood stasis syndrome (QDBSS). METHODS: Totally 188 UU infection patients of QDBSS were randomly assigned to two groups, the treatment group and the control group. Patients in the treatment group were treated with PP (10 g each time, thrice daily, 14 consecutive days as one therapeutic course), while those in the control group took azithromycin (10 g each day, 7 consecutive days as one therapeutic course). They were continually treated for 3 therapeutic courses. The clinical symptom integrals were observed in the two groups before and after treatment. The short-term efficacy was judged. Their recurrence rates were followed-up to assess their long-term efficacies. RESULTS: The total effective rate of the comprehensive efficacy in the treatment group was 91.4%, while it was 79. 3%in the control group, showing no statistical difference between the two groups (P > 0.05). Better effects were obtained in improving Chinese medical clinical symptoms in the treatment group (P <0.01). There was no statistical difference in the negative conversion rate between the two groups after treatment (P >0. 05). There was statistical difference in the recurrence rate between the two groups (12. 82% vs 54.76%,P <0. 05). CONCLUSIONS: PP showed equivalent effects in treating UU infection patients of QDBSS to those of azithromycin. But PP showed obvious advantages over azithromycin in improving Chinese medical syndromes.

[Correlation between ARID5B Gene SNP and MTX Resistance in Children with ALL].

OBJECTIVE: To investigate the correlation between single-nucleotide polymorphism (SNP) of ARID5B gene and resistance to methotrexate (MTX) in children with acute lymphoblastic leukemia (ALL). METHODS: A total of 144 children with ALL who were treated in General Hospital of Ningxia Medical University from January 2015 to November 2021 were enrolled and divided into MTX resistant group and non-MTX resistant group, with 72 cases in each group. Matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS) technology was used to measure the SNP of ARID5B gene in all children and analyze its correlation with MTX resistant. RESULTS: There were no significant differences in the genotype and gene frequency of rs7923074, rs10821936, rs6479778, and rs2893881 between MTX resistant group and non-MTX resistant group (P>0.05). The frequency of C/C genotype in the MTX resistant group was significantly higher than that in the non-MTX resistant group, while the frequency of T/T genotype was opposite (P<0.05). The frequency of C allele in the MTX resistant group was significantly higher than that in the non-MTX resistant group, while the frequency of T allele was opposite (P<0.05). Multivariate logistic regression analysis showed that ARID5B gene rs4948488 TT genotype and T allele frequency were risk factors for MTX resistant in ALL children (P<0.05). CONCLUSION: The SNP of ARID5B gene is associated with MTX resistant in ALL children.