Objective To study stability of the deterministic tumor-immune system with time delay by means of linear stability analysis method. Methods In tumor-immune system, since it took some time for immune cells to recognize tumor cells and respond appropriately, time delay was considered in this process, then the model was simplified by using Taylor expansion of small delay, and the equilibrium points were solved out. By linear stability analysis method, the stability of these equilibrium points was studied. Finally, the trajectory of the system and that around each equilibrium point were simulated by numerical calculation method, so as to verify the result of theoretical analysis. Results The system had four meaningful equilibrium points with small delay, including a stable focus, a stable node, and two saddles. Moreover, the type and stability of these equilibrium points were not affected by the delay. Numerical simulation demonstrated the conclusion from theoretical analysis. Conclusions Under the condition of small delay, the type and stability of equilibrium points in the system are notaffected by the delay. The results are helpful to further understand dynamic mechanisms of tumor immune response, and provide references for tumor growth and treatment

In order to evaluate the diagnostic accuracy of glucose-6-phosphate isomerase in patients with rheumatoid arthritis, retrieval was performed using the data bases of Medline, Embase, Cochrane library, Cmcc and Cbmdisc (1990 to 2007). We included the articles which reported the studies of GPI measured by enzyme-linked immunosorbent assay in the diagnosis of RA patients. Then we reviewed 15 article and used RevMan Software for analysis; the heterogeneity among the articles was determined to be high (chi2 = 191.65, P < 0.00001). When we analyzed the 5 articles wherein serum was used as the standard, we noticed homogeneity (chi2 = 6.97, P = 0.14). The summary sensitivity was 25%; the summary specificity was 80%; the area under the curve was 0.6279. Our study demonstrated that GPI exhibited high specificity and low sensitivity in diagnosing RA cases. We suggest that GPI be used in conjunction with some assay or other that is characterized by high sensitivity.
Arthritis, Rheumatoid ; blood ; diagnosis ; Enzyme-Linked Immunosorbent Assay ; Female ; Glucose-6-Phosphate Isomerase ; blood ; Humans ; Male ; ROC Curve ; Sensitivity and Specificity

Objective To observe the effects of fecal microbiota transplantation on intestinal microbiota and brain function in sepsis rats. Methods Sixty male Sprague Dawley (SD) rats were divided into sham operation group, model group and fecal microbiota transplantation (FMT) group by random number table, each group 20 rats. The rat model of sepsis was established by injection of lipopolysaccharide (LPS) 10 mg/kg in tail vein. FMT group received nasogastric infusion of feces from healthy donor. Fecal samples were collected on the 6th day after the modeling to detect the levels of intestinal microbiota composition; the brain function was also evaluated by electroencephalogram (EEG), and the proportion of each waveform in EEG was calculated. After sacrifice of rats in different groups, the brain tissues were taken, the levels of protein expression and positive cells of Iba-1 in brain tissue were detected by Western Blot and immunohistochemistry method. Results ① Intestinal flora analysis showed that: the diversity index and Chaol index of the intestinal microbiota in model group were significantly lower than that in sham operation group (observed species:282±40 vs. 473±37, Chao1 index: 730±21 vs. 837±27, both P < 0.05); compared with the model group, the diversity index and Chaol index in FMT group were obviously higher (observed species: 461±20 vs. 282±40, Chao1 index:840±16 vs. 730±21, both P < 0.05). At phylum, family, genus level analysis showed that the proportion of Firmicutes phylum and Fusobacterium were obviously lower than those of sham operation group [Firmicutes phylum (22.12±1.34)% vs. (78.01±1.23)%, Fusobacterium: (2.03±0.17)% vs. (5.03±0.19)%, both P < 0.05], and the proportions of Proteobacteria, Bacteroidetes phyla and Acidaminococcaceae, Fusobacteriaceae, Enterbacteriacecae, Alistipes were markedly higher in model group [Proteobacteria: (70.21±2.35)% vs. (19.45±2.17)%, Bacteroidetes phyla: (4.12±0.19)% vs. (2.50±0.64)%, Acidaminococcaceae: (12.51±0.87)% vs. (1.01±0.12)%, Fusobacteriaceae: (13.62±1.27)% vs. (2.31±0.19)%, Enterbacteriacecae: (18.24±2.13)% vs. (4.15±1.51)%, Alistipes: (4.53±0.27)% vs. (1.47±0.33)%, all P < 0.05]; compared with the model group, the proportion of Firmicutes phylum and Faecalibacterium in FMT group were significantly higher [Firmicutes phylum: (72.14±2.31)% vs. (22.12±1.34)%, Faecalibacterium: (5.01±0.27)% vs. (2.03±0.17)%, both P < 0.05], and Proteobacteria, Bacteroidetes phyla and Acidaminococcaceae, Fusobacteriaceae, Enterbacteriacecae in FMT group were obviously lower [Proteobacteria: (14.23±1.98)% vs. (70.21±2.35)%, Bacteroidetes phyla: (3.15±0.18)% vs. (4.12±0.19)%, Acidaminococcaceae: (0.91±0.11)% vs. (12.51±0.87)%, Fusobacteriaceae: (1.25±0.15)% vs. (13.62±1.27)%, Enterbacteriacecae: (3.50±0.21)% vs. (18.24±2.13)%, all P < 0.05]. ② EEG analysis showed that the percentages of δ wave in EEG in model group was significantly higher after modeling than that in sham operation group [(16.86±0.50)% vs. (10.67±0.65)%, P < 0.05]; the ratios of δ wave in EEG was significantly lower in FMT group than that in the model group [(12.87±0.60)% vs. (17.35±0.41)%, P <0.05]. The incidence of abnormal EEG in sham operation group was 0, the incidence of abnormal EEG in model group was significantly increased [the ratios of δpredominant wave, θpredominant wave, low-voltage were 66.7% (6/9), 66.7% (6/9), 77.8% (7/9) respectively], the ratios of above abnormal waves in EEG in FMT group were obviously lower than those in model group [the ratios of above abnormal waves in FMT group were respectively 9.1% (1/11), 9.1% (1/11), 18.2%(2/11)]. ③ Western Blot analysis showed that the protein expression of Iba-1 in cortex in model group obviously was higher than that in sham operation group (Iba-1/β-actin: 1.39±0.16 vs. 0.67±0.18, P < 0.05); the expression of Iba-1 in cortex tissue of FMT group was markedly lower than that in model group (Iba-1/β-actin: 0.51±0.14 vs. 1.39±0.16, P < 0.05). ④ Immunohistochemistry of Iba-1 in cortex analysis showed that there were no Iba-1 positive cells in the cortex in sham operation group; Iba-1 positive cells were found in the cortex in model group; the number of Iba-1 positive cells in FMT group was less than that in model group. Conclusion FMT can improve the construction of intestinal microbiota, and ameliorate the brain dysfunction in SAE.

Objective To evaluate the diagnostic value of MSCT angiography and postprocessing techniques in the diagnosis of spontaneous isolated dissection of superior mesenteric artery(SIDSMA).Methods Twenty patients with SIDSMA performed with MSCT angiography were analyzed retrospectively.The volume data were transferred to the workstation for image postprocessing and performed with various postprocessing techniques such as multi-planar reconstruction(MPR),curved planar reconstruction(CPR), volume rendering(VR)and maximum intensity projection(MIP).Results The dissection length of SIDSMA was positively correlated with visual analogue scale(VAS).MPR,CPR and VR clearly showed the intimal flap,true and false lumen.MPR and CPR displayed more entries of dissection than VR.VR demonstrated the extension of the involved aorta and its branches,but cannot satisfactorily demonstrate the entry of SIDSMA.Conclusion MSCT angiography is of positive applicable value to the diagnosis of SIDSMA.MPR, CPR and VR may be optimal choice as post processing techniques for diagnosis of SIDSMA.

Objective:To establish an isotope dilution liquid chromatography-tandem mass spectrometry (ID-LC-MS/MS) method for the determination of L-tryptophan and its metabolites in serum.Methods:The methodology was established and evaluated using serum samples collected from 166 healthy subjects undergoing physical examinations at West China Hospital from November 2022 to January 2023 were collected. Isotope-labeled markers of L-tryptophan (Trp), L-kynurenine (Kyn), and kynurenic acid (KA) were used as internal standards. After protein precipitation treatment of serum samples, LC-MS/MS was used to determine Trp, Kyn, and KA simultaneously. The selectivity, specificity, linearity, detection limit (LOD), quantification limit (LOQ), carry-over, precision, recovery rate, matrix effect, and dilution integrity of the method were evaluated.Results:The linearity of Trp, Kyn, and KA was demonstrated to be 0.999. The LODs were 0.10 μmol/L, 0.01 μmol/L and 1.00 nmol/L, respectively. The LOQs were 0.20 μmol/L, 0.04 μmol/L and 2.00 nmol/L, respectively. The intra-batch precision and inter-batch precision were below<10%. The average recovery rate and the relative matrix effect were all about 100%. The samples over the upper limit of quantitation can be diluted up to 16 times. The Trp concentration, Kyn concentration, KA concentration, Kyn/Trp ratio, and KA/Kyn ratio in serum of healthy subjects were 59.55±10.92 μmol/L, 1.85±0.43 μmol/L, 39.89±17.93 nmol/L, (31.64±8.19)×10 -3 and 21.51±6.72, respectively. Conclusion:An ID-LC-MS/MS method was successfully established for the quantitative determination of Trp, Kyn, and KA in serum. The method proved to be simple, rapid, sensitive, accurate, and reliable, providing robust support for clinical research related to these analytes.