Objective]To establish a new method for grafting ratio(GR) analysis of deoxycholic acid grafted chitosan(CS-DCA). [Methods]In this study, linear potentiometric titration(LPT) and 2,4,6-trinitrobenzenesulfonicacid(TNBS) were introduced to measure the GR of CS-DCA, using the 1H-nuclear magnetic resonance(1H-NMR) as reference, the results obtained by the two methods were analyzed to find a method to substitute H-NMR. [Results]There was no significant difference of the data determined by 1H-NMR and LPT(P>0.05), however, it didn't apply to 1H-NMR and TNBS(P<0.05), the results indicated that LPT had equivalent accuracy of 1H-NMR. Using 1H-NMR method as the standard reference, the relative error was no more than 3.8% for the method of LPT, and the maximum relative error for the method of TNBS was up to 12.8%, it meant that LPT had higher precision. [Conclusion]LPT is an economical, rapid and accurate method for the GR analysis of CS-DCA.

he activity of MMP-2 and MMP-9 via ERK1/2 signaling pathway.

Objective: To observe the integration frequency of aadA2 resistance cassette at attI site of the integron under different concentration of streptomycin. Methods: Class 1 integron with known gene sequence was cloned into plasmid pACYC184 to produce recombinant plasmid pACIDA, meanwhile the integrase gene was cloned into plasmid pET28a to construct recombinant plasmid pETINT. These two recombinant plasmids were consecutively transformed into E. coli BL(DE3). These transformed bacteria was cultured in the LB medium at 37 ℃ overnight with addition of different concentration of streptomycin. The copy number of total integrons and the copy number of integrated aadA2 at attI site of integrons were determined by using real-time PCR. and the integration frequency is the result of the former divided by the latter. Results: The resulting frequencies were (1.97±0.24)×10^-3, (3.23±1.77)×10^-3, (3.27±0.67)×10^-3, 0.45±0.13 and 1.32±0.11, with respective streptomycin concentrations of 0, 20, 30, 40 and 50 μg/ml. The background frequency of integration without integrase overexpression was less than (1.75±0.33)×10^-7. Conclusion These findings indicate that antibiotic concentration significantly increase recombination frequency of aadA2 resistance cassette at attI site of the integron, catalyzed by integron integrase.(Chin J Lab Med, 2018, 41: 531-535)

Objective:To investigate the effects of ceftriaxone(CTX) on nuclear factor erythroid 2-related factor 2(Nrf2)/glutathione peroxidase 4(GPX4) pathway and ferroptosis in early brain injury in rats with subarachnoid hemorrhage(SAH).Methods:Forty-eight clean grade male SD rats were randomly divided into sham operation group (Sham group), SAH group, SAH+ CTX group and SAH+ CTX+ Nrf2 inhibitor group (SAH+ CTX+ ML385 group) according to the random number table with 12 rats in each group.Seven days before modeling, rats in SAH+ CTX+ ML385 group were injected intraperitoneally with ML385 (30 mg · kg -1) once a day for consecutive 7 days.And 5 days before modeling, rats in SAH+ CTX group and SAH+ CTX+ ML385 group were treated with CTX(200 mg · kg -1) by intraperitoneal injection once a day for five consecutive days.Rats in Sham group and SAH group were intraperitoneally injected with the same amount of 0.9% sodium chloride solution.After 24 hours of modeling, the neurological function score and brain tissue water content of rats in each group were measured.HE staining was used to observe the morphology of neurons in CA1 and CA3 regions of hippocampus.Prussian blue staining was used to observe the iron deposition in cerebral cortex.Spectrophotometer was used to determine the iron content, malonic dialdehyde(MDA) content, glutathione(GSH) content and GPX4 activity in cerebral cortex.Western blot was used to detect the expression levels of Nrf2 and GPX4 proteins in cerebral cortex.SPSS 23.0 was used for statistical analysis.One-way ANOVA was used to compare the mean of multiple groups of samples, and Dunnett- t test was used for further pairwise comparison between groups. Results:There was a statistically significant difference in the neurological function scores of rats in the four groups 24 hours after SAH ( F=48.40, P<0.001). The neurological function score of rats in the SAH group 24 hours after SAH was significantly lower than those in Sham group and SAH+ CTX group (both P<0.05). The brain water content of rats in the four groups 24 h after SAH was statistically significant ( F=49.61, P<0.001). The brain water content of rats in the SAH group 24 h after SAH was significantly higher than that in Sham group and SAH+ CTX group(both P<0.05). There was statistically significant differences in the number of neuronal necrosis in CA1 and CA3 regions of hippocampus in the four groups 24 hours after SAH ( F=17.44, 246.50, both P<0.001). The numbers of neuronal necrosis in CA1 and CA3 regions of hippocampus in SAH group were significantly higher than those in Sham group and SAH+ CTX group, and the numbers of neuronal necrosis in CA1 and CA3 regions of hippocampus in SAH+ CTX+ ML385 group were significantly higher than those in SAH+ CTX group (all P<0.05). Twenty-four hours after SAH, the amount of iron deposited in the cerebral cortex of rats in the four groups was statistically significant ( F=2 363.0, P<0.001). The iron deposition in the cerebral cortex of rats in the SAH group was significantly higher than those in Sham group and SAH+ CTX group (both P<0.05). There were significant differences in iron content, MDA content, GSH content and GPX4 activity in the cerebral cortex of the four groups 24 h after SAH( F=2 380.0, 1 322.0, 789.1, 815.5, all P<0.001). The content of iron and MDA in the cerebral cortex of rats in SAH group were significantly higher than those in Sham group, while the content of GSH and the activity of GPX4 were significantly lower than those in Sham group (all P<0.05). The content of iron and MDA in the cerebral cortex of rats in SAH+ CTX group were lower than those in SAH group, and the content of GSH and the activity of GPX4 were higher than those in SAH group (all P<0.05). At 24 h after SAH, the expression levels of Nrf2 and GPX4 protein in the cerebral cortex of the four groups were statistically significant ( F=888.7, 1 556.0, both P<0.001). The protein expression levels of Nrf2 (0.382±0.014) and GPX4 (0.329±0.019) in the cerebral cortex in SAH group were lower than those in Sham group ((0.746±0.009), (0.953±0.009)) (both P<0.05). The expression levels of Nrf2 (0.631±0.006) and GPX4 (0.833±0.008) protein in the cerebral cortex in the SAH+ CTX group were significantly higher than those in the SAH group (both P<0.05). The expression levels of Nrf2 (0.427±0.009) and GPX4 (0.525±0.011) protein in the cerebral cortex in SAH+ CTX+ ML385 group were significantly lower than those in SAH+ CTX group (both P<0.05). Conclusion:Ceftriaxone may inhibit ferroptosis during EBI in SAH rats by regulating Nrf2/GPX4 signal axis.

Objective:To systematically evaluate the prevalence of norovirus causing sporadic acute gastroenteritis in China.Methods:Relevant articles on acute gastroenteritis caused by norovirus in China published between January 2010 and October 2023 were retrieved from Wanfang, CNKI and PubMed database. The articles met inclusion and exclusion criteria were enrolled in this study. Excel software and SPSS20.0 software were used for statistical analysis. The epidemiological features of sporadic cases of acute gastroenteritis caused by norovirus in China were summarized using descriptive statistical analysis.Results:A total of 500 articles were included in this study, involving 784 486 cases of acute gastroenteritis and 670 292 samples in 32 provinces and regions. Norovirus GⅡ was the predominant genogroup causing acute gastroenteritis in China in recent years, but there were significant differences in the distribution of genotypes and epidemic strains at different times. GⅡ.4 was the predominant genotype in each year, and GⅡ.4/2006b and GⅡ.4 /Sydney_2012 were the main epidemic strains. Norovirus-related diarrhea occurred throughout the year, especially between the months of October and December. The incidence of norovirus infection was high in children under five years old and varied in different regions.Conclusions:Norovirus GⅡ was the predominant genogroup causing norovirus-related sporadic acute gastroenteritis in China, but there was an obvious genetic evolutionary trend in the epidemic strains. Factors such as epidemic strains, season and geographical region should be considered when making strategies for the prevention and control of norovirus-related diarrhea and developing vaccines.

ObjectiveTo investigate the effects of Tongluo Juanbi granules on chondrocyte apoptosis and Toll-like receptor 4 （TLR4）/myeloid differentiation factor 88 （MyD88）/nuclear factor-κB （NF-κB） signaling pathway of rabbits with knee osteoarthritis （KOA） and study the mechanism of Tongluo Juanbi granules in the prevention and treatment of KOA. MethodThirty New Zealand rabbits were randomly assigned to the following five groups （n=6）： sham group， model group， low-dose and high-dose groups of Tongluo Juanbi granules （4.1 and 8.2 g·kg^-1·d^-1）， and celecoxib group （10.9 mg·kg^-1·d^-1）. The KOA model was established by destabilization of the medial meniscus （DMM） for six weeks. Six weeks after the modeling， the drug was given once a day for eight weeks. The pathological changes of cartilago articularis were observed by hematoxylin-eosin （HE） staining and Safranin O-Fast Green staining. Terminal deoxynucleotidyl transferase dUTP nick end labeling （TUNEL） staining was performed to detect chondrocyte apoptosis. Enzyme-linked immunosorbent assay （ELISA） was used to detect the contents of interleukin-1β （IL-1β） and tumor necrosis factor-α （TNF-α） in synovial fluid. The mRNA and protein expression levels of genes related to the TLR4/MyD88/NF-κB signaling pathway were detected by real-time fluorescence quantitative polymerase chain reaction （Real-time PCR） and Western blot， respectively. ResultCompared with the sham group， the cartilago articularis of the model group significantly degenerated. Mankin's score was increased （P<0.01）， and the contents of IL-1β and TNF-α in synovial fluid were increased （P<0.01）. The number of apoptosis of chondrocytes was increased （P<0.01）. The mRNA and protein expressions of TLR4， MyD88， and NF-κB p65 in cartilage tissue were up-regulated （P<0.01）， while the mRNA and protein expressions of Bcl-2 were down-regulated （P<0.01）. Compared with the model group， chondrocyte degeneration in both low-dose and high-dose groups of Tongluo Juanbi granules was improved， and Mankin's score was decreased （P<0.01）. The contents of IL-1β and TNF-α were decreased （P<0.01）， and the number of apoptosis of chondrocytes was decreased （P<0.01）. The mRNA and protein expressions of TLR4， MyD88， and NF-κB p65 in cartilage tissue were down-regulated （P<0.01）， while the mRNA and protein expressions of Bcl-2 were up-regulated （P<0.01）. In addition， in the above observation indicators， the high-dose group of Tongluo Juanbi granules was significantly superior to the low-dose group of Tongluo Juanbi granules. ConclusionTongluo Juanbi granules could inhibit chondrocyte apoptosis in rabbits with KOA and improve cartilage degeneration， which may be related to inhibiting inflammatory responses mediated by TLR4/MyD88/NF-κB signaling pathway.

The basic pathological change of diabetic macroangiopathy is atherosclerosis， and the metabolism legacy effect of hyperglycemia will cause continuous damage to the large vessels. Oxidative stress is a common mechanism for diabetes and its chronic complications and it is also the basis of the metabolism legacy effect which keeps damaging the large vessels. Anti-oxidant therapy can delay the course of diabetic macroangiopathy. According to the theory of traditional Chinese medicine （TCM）， the pathogenicity of hidden pathogen is concealing， lingering， and refractory. On the basis of the syndrome and treatment of collateral diseases， vessel-collateral theory， and hidden pathogen theory of TCM， the pathological changes of diabetic macroangiopathy are summarized as pathogen concealment-accumulation of sugar and lipids leading to phlegm and blood stasis-accumulation of toxins-damage to vessels and collaterals-hardening vessels. The core pathogenesis is the hidden pathogen damaging the collaterals， and the basic pathological change is vessel hardening. The toxins of sugar， lipid， phlegm， and stasis are the pathological products and the key to be treated. According to this theory， the medicinal materials with the functions of activating blood to dredging collaterals， resolving phlegm to clearing collaterals， Promoting qi to unblocking collaterals and removing toxins to shunting collaterals can be selected for prescription. These medicinal materials can inhibit the generation of reactive oxygen species， affect the oxidase activity， and enhance the antioxidant capacity， thereby regulating the oxidative stress response， protecting the vascular endothelial function， reducing the damage of the large blood vessels， and slowing down the progression of the disease. Such therapy is of great significance in clinical practice and research， providing a new idea for the prevention and treatment of diabetic macroangiopathy.

The basic pathological change of diabetic macroangiopathy is atherosclerosis （AS）， which is mainly associated with vascular endothelial cells （VECs） injury， oxidative stress， glucose and lipid metabolism disorders， hemorheological abnormalities， and endoplasmic reticulum stress. The injury and dysfunction of VECs are the initiating factors of diabetic macroangiopathy. Autophagy is a subcellular self-protection mechanism that regulates basic intracellular metabolism through lysosome-mediated degradation of proteins and damaged organelles to maintain homeostasis. Insufficient autophagy of VECs leads to enhanced inflammation， apoptosis， and oxidative stress of VECs， which promotes AS. According to the theory of traditional Chinese medicine （TCM）， diabetic macroangiopathy corresponds to the syndrome of internal deficiency and pathogen invasion， with Qi deficiency and stagnation as the key pathogenesis. Qi deficiency is the root cause， and Qi stagnation is the manifestation. The disease occurs with the initial cause of nutrient-defense disharmony and instability of vessels， the main cause of the deficiency of kidney Qi and the lack of source for generation and transformation， the internal cause of Qi and blood loss in the viscera and the stagnation of Qi， blood， and fluid， and the superficial cause of the stagnation of pathological products and the damage of vessels. Autophagy is a microscopic manifestation of Qi， which has the function of dispelling pathogens and maintaining homeostasis. Insufficient autophagy of VECs leads to Qi deficiency and stagnation， and the gradual deficiency and heavy stagnation of Qi lead to insufficient autophagy， which form a vicious cycle. Modern research has demonstrated that regulating the autophagy of VECs is the main way to prevent and treat AS， and TCM can exert the therapeutic effect in a multi-target and multi-pathway manner. Therefore， based on the theory of Qi deficiency and stagnation， the method of tonifying deficiency of and removing stagnation can be adopted to select prescriptions for regulating the autophagy of VECs and treating AS， which can slow down the procession of diabetic macroangiopathy.