Effect of alisol A on cerebral ischemia reperfusion injury by protecting blood brain barrier and its mechanism / 中国药理学通报

Aim To investigate whether alisol A (AA) could improve the blood brain barrier (BBB) mediated cortex cerebral ischemia-repeifusion injury (CIRI) by inhibiting matrix metalloproteinase 9 (MMP-9). Methods The global cerebral ischemia- reperfusion (GCI/R) model in mice was established, and the AA was intragastric injected subsequently for seven days. The modified neurological severity scores (mNSS), open field test and Y-maze test were applied to detect neurological function. Magnetic resonance spectroscopy (MRS) was used to detect relevant neu- rosubstance metabolism in cortex of mice. Transmission electron microscope (TEM) was employed to observe the ultrastructure of BBB in cortex. Western blot and immunohistochemistry were used to detect the MMP-9 level in cortex. The binding possibility of A A and MMP-9 was determined by molecular docking. Results Compared with Sham group, mice in GCI/R group have an increased mNSS score but decreased at total distance and center distance to total distance ratio in open field test as well as alternation rate in Y-maze test (P<0.01). While mice in GCI/R + AA group have a decreased mNSS score but increased at total distance and center distance to total distance ratio in open field test as well as alternation rate in Y-maze test (P<0.01) compared with GCI/R group. MRS results found that in cortex of GCI/R group mice, the level of GABA and NAA significantly decreased while the Cho, mI and Tau level increased (P<0.01). Whereas in GCI/R + AA group mice, the GABA and NAA level increased and the Cho, ml and Tau decreased significantly (P<0.01). By TEM we observed that the basilemma of cerebral microvessels collapsed, the lumen narrowed, the endothelial cells were active and plasma membranes ruffled, gaps between cells were enlarged and tight junctions were damaged and the end feet of astrocytes were swollen in GCI/R group mice. While in GCI/R + AA group mice, the lumen was filled, plasma membranes of endothelial cells were smooth, tight junctions were complete and end feet of astrocytes were in normal condition. Western blot and immunohistochemistry both found that the MMP-9 level increased in GCI/R group mice (P < 0.01) and decreased in GCI/R + AA group mice (P < 0.05). Molecular docking proved the binding between aliso A and MMP9 through TYR-50 and ARG-106, and the binding energy was calculated as -6.24 kcal · mol

Molecular mechanism of artesunate attenuates the release of proinflammatory cytokines from macrophages / 中国临床药理学与治疗学

AIM: Lipopolysaccharide (LPS) on the cell membrane of gram negative bacteria is closely related to the occurrence and development of severe acute pancreatitis (SAP). Local and systemic monocyte / macrophages play an important role in the inflammatory process of SAP. Artesunate (AS) was reported to protect rats with severe acute pancreatitis by reducing the release of proinflammatory cytokines. This study further explored the molecular mechanism of anti-inflammatory effect of AS. METHODS: The release of proinflammatory cytokines in the supernatant were studied by enzyme-linked immunosorbent assay. Then, the mRNA expressions of PI3K-III and its key molecules in signaling pathway were detected by real-time quantitative PCR. Finally, the phosphorylation levels of PI3KIII were detected by Western blot. RESULTS: AS could significantly inhibit the release of proinflammatory cytokines from mouse macrophage induced by LPS. Autophagy inhibitor 3-methyladenine (3-MA) could significantly inhibit the release of TNF-α from mouse macrophages induced by LPS; LPS significantly increased the mRNA expression of PI3KIII and its key molecules in mouse peritoneal macrophages (PMs). Finally, AS could significantly inhibit the increase of PI3K-III phosphorylation induced by LPS in PMs. CONCLUSION: The anti-inflammatory mechanism of AS is closely related to the inhibition of PI3K-III phosphorylation.

Forensic Pathological Diagnosis of Acute and Old Myocardial Infarction Using Fourier Transform Infrared Spectroscopy / 法医学杂志

OBJECTIVES@#Fourier transform infrared spectroscopy (FTIR) was used to analyze myocardial infarction tissues at different stages of pathological change to achieve the forensic pathology diagnosis of acute and old myocardial infarction.@*METHODS@#FTIR spectra data of early ischemic myocardium, necrotic myocardium, and myocardial fibrous tissue in the left ventricular anterior wall of the sudden death group of atherosclerotic heart disease and the myocardium of the normal control group were collected using hematoxylin-eosin (HE) and immunohistochemistry (IHC) staining as a reference, and the data were analyzed using multivariate statistical analysis.@*RESULTS@#The mean normalized spectra of control myocardium, early ischemic myocardium and necrotic myocardium were relatively similar, but the mean second derivative spectra were significantly different. The peak intensity of secondary structure of proteins in early ischemic myocardium was significantly higher than in other types of myocardium, and the peak intensity of the α-helix in necrotic myocardium was the lowest. The peaks of amide Ⅰ and amide Ⅱ in the mean normalized spectra of myocardial fibrous tissue significantly shifted towards higher wave numbers, the peak intensities of amide Ⅱ and amide Ⅲ were higher than those of other types of myocardium, and the peak intensities at 1 338, 1 284, 1 238 and 1 204 cm-1 in the mean second derivative spectra were significantly enhanced. Principal component analysis (PCA) and partial least square-discriminant analysis (PLS-DA) showed that FTIR could distinguish different types of myocardium.@*CONCLUSIONS@#FTIR technique has the potential to diagnose acute and old myocardial infarction, and provides a new basis for the analysis of the causes of sudden cardiac death.

Progress on the application of capsular tension ring in high myopia combined with cataract / 国际眼科杂志(Guoji Yanke Zazhi)

In recent years, the incidence of high myopia complicated with cataract shows a gradual upward trend. Due to the special anatomical structure and lesion nature of high myopia, the difficulty and various complications of such patients are much higher than those of ordinary cataract surgery. With the continuous advancement of design and materials, the indications for capsular tension ring(CTR)have gradually expanded. Especially for patients with high myopia,it can maintain the stability of intraocular lens position, assist the relaxation of the suspensory ligament, inhibit the migration and proliferation of residual lens epithelial cells after surgery, improve the visual quality of patients and reduce the incidence of retinal detachment. This paper reviewed the history of CTR, its clinical application, and the effect of CTR on high myopia complicated with cataract.

Effects of Linc00460 on Aerobic Glycolysis in Breast Cancer Cells via Sponge Adsorption of miR-320a / 肿瘤防治研究

Objective To explore the effect of Linc00460 on the aerobic glycolysis of breast cancer (BC) cells through sponge adsorption of miR-320a. Methods The qRT-PCR method was used to detect Linc00460 and miR-320a expression levels in normal breast epithelial cell line MCF-10A and five BC cell lines. The effect of interfering Linc00460 on miR-320a expression was detected by qRT-PCR. The double luciferase reporter gene experiment was used to analyze the targeting relationship between miR-320a and Linc00460. In addition, the si-Linc00460 and miR-320a inhibitor were co-transfected into MDA-MB-231 cells, and the expression level of miR-320a in the cells was detected by qRT-PCR; cell proliferation ability was measured by the MTT method; glucose uptake rate was detected by 2-NBDG method; the content of lactic acid in the cell supernatant was detected by colorimetric method; the key enzymes of glycolysis was detected by the enzyme activity kit; and the expression levels of the key proteins in the glycolysis pathway were detected by Western blot. Results Linc00460 was highly expressed in five BC cell lines, while miR-320a was lowly expressed as compared with MCF-10A cells. The expression of miR-320a in MDA-MB-231 cells significantly increased after interfering with Linc00460. The double luciferase reporter gene experiment confirmed that miR-320a and Linc00460 could target binding. Interfering with the expression of Linc00460 could inhibit MDA-MB-231 cells proliferation (all P=0.000), reduce the rate of cellular glucose uptake and the content of lactic acid in the cell supernatant (all P=0.000), inhibit the activities of PFK, PK, and LDH enzymes (all P=0.000), and downregulate the protein expression levels of PFKM, GLUT1, and LDHA (all P=0.000). Meanwhile, inhibition of miR-320a could reverse the inhibitory effect of si-Linc00460 on the proliferation and glycolysis of MDA-MB-231 cells (all P=0.000 or 0.001). Conclusion Linc00460 might adsorb miR-320a, consequently leading to upregulation of PFKM expression, thereby promoting aerobic glycolysis in BC cells.

Comparison among Four Deep Learning Image Classification Algorithms in AI-based Diatom Test / 法医学杂志

OBJECTIVES@#To select four algorithms with relatively balanced complexity and accuracy among deep learning image classification algorithms for automatic diatom recognition, and to explore the most suitable classification algorithm for diatom recognition to provide data reference for automatic diatom testing research in forensic medicine.@*METHODS@#The "diatom" and "background" small sample size data set (20 000 images) of digestive fluid smear of corpse lung tissue in water were built to train, validate and test four convolutional neural network (CNN) models, including VGG16, ResNet50, InceptionV3 and Inception-ResNet-V2. The receiver operating characteristic curve (ROC) of subjects and confusion matrixes were drawn, recall rate, precision rate, specificity, accuracy rate and F1 score were calculated, and the performance of each model was systematically evaluated.@*RESULTS@#The InceptionV3 model achieved much better results than the other three models with a balanced recall rate of 89.80%, a precision rate of 92.58%. The VGG16 and Inception-ResNet-V2 had similar diatom recognition performance. Although the performance of diatom recall and precision detection could not be balanced, the recognition ability was acceptable. ResNet50 had the lowest diatom recognition performance, with a recall rate of 55.35%. In terms of feature extraction, the four models all extracted the features of diatom and background and mainly focused on diatom region as the main identification basis.@*CONCLUSIONS@#Including the Inception-dependent model, which has stronger directivity and targeting in feature extraction of diatom. The InceptionV3 achieved the best performance on diatom identification and feature extraction compared to the other three models. The InceptionV3 is more suitable for daily forensic diatom examination.

Research Progress of Automatic Diatom Test by Artificial Intelligence / 法医学杂志

Diatom test is the main laboratory test method in the diagnosis of drowning in forensic medicine. It plays an important role in differentiating the antemortem drowning from the postmortem drowning and inferring drowning site. Artificial intelligence (AI) automatic diatom test is a technological innovation in forensic drowning diagnosis which is based on morphological characteristics of diatom, the application of AI algorithm to automatic identification and classification of diatom in tissues and organs. This paper discusses the morphological diatom test methods and reviews the research progress of automatic diatom recognition and classification involving AI algorithms. AI deep learning algorithm can assist diatom testing to obtain objective, accurate, and efficient qualitative and quantitative analysis results, which is expected to become a new direction of diatom testing research in the drowning of forensic medicine in the future.

Antibody neutralization to SARS-CoV-2 and variants after one year in Wuhan

Most COVID-19 patients can build effective humoral immunity against SARS-CoV-2 after recovery(1, 2). However, it remains unknown how long the protection can maintain and how efficiently it can protect people from the reinfection of the emerging SARS-CoV-2 variants. Here we evaluated the sera from 248 COVID-19 convalescents around one year post-infection in Wuhan, the earliest epicenter of SARS-CoV-2. We demonstrated that the SARS-CoV-2 immunoglobulin G (IgG) maintains at a high level and potently neutralizes the infection of the original strain (WT) and the B.1.1.7 variant in most patients. However, they showed varying degrees of efficacy reduction against the other variants of concern (P.1, B.1.525, and especially B.1.351) in a patient-specific manner. Mutations in RBD including K417N, E484K, and E484Q/L452R (B.1.617) remarkably impair the neutralizing activity of the convalescents sera. Encouragingly, we found that a small fraction of patients sera showed broad neutralization potency to multiple variants and mutants, suggesting the existence of broadly neutralizing antibodies recognizing the epitopes beyond the mutation sites. Our results suggest that the SARS-CoV-2 vaccination effectiveness relies more on the timely re-administration of the epitope-updated vaccine than the durability of the neutralizing antibodies.

Occurrence of COVID-19 symptoms during SARS-CoV-2 infection defines waning of humoral immunity

Approximately half of the SARS-CoV-2 infections occur without apparent symptoms, raising questions regarding long-term humoral immunity in asymptomatic individuals. Plasma levels of immunoglobulin G (IgG) and M (IgM) against the viral spike or nucleoprotein were determined for 25,091 individuals enrolled in a surveillance program in Wuhan, China. We compared 405 asymptomatic individuals with 459 symptomatic COVID-19 patients. The well-defined duration of the SARS-CoV-2 endemic in Wuhan allowed a side-by-side comparison of antibody responses following symptomatic and asymptomatic infections without subsequent antigen re-exposure. IgM responses rapidly declined in both groups. However, both the prevalence and durability of IgG responses and neutralizing capacities correlated positively with symptoms. Regardless of sex, age, and body weight, asymptomatic individuals lost their SARS-CoV-2-specific IgG antibodies more often and rapidly than symptomatic patients. These findings have important implications for immunity and favour immunization programs including individuals after asymptomatic infections. One-Sentence SummaryPrevalence and durability of SARS-CoV-2-specific IgG responses and neutralizing capacities correlate with COVID-19 symptoms.

Relationship between Stress Hyperglycemia and Catheter-related Urinary Tract Infection in Stroke Patients / 中国医学科学院学报

Objective To verify the relationship between catheter-related urinary tract infection(CAUTI)and stress hyperglycemia during catheter retention in stroke patients. Methods We used nosocomial infection monitoring system to track the status of CAUTI in stroke patients in a hospital.The study cohort was all the patients who received retention catheterization from January 2016 to March 2020.According to the nested case-control design,multivariate logistic regression analysis was performed to explore the relationship between stress hyperglycemia and CAUTI in stroke patients with indwelling catheter. Results A total of 322 cases of CAUTI and 644 cases of non-CAUTI were enrolled in this study.The length of stay in the case group was(20.68 ± 3.73)d,significantly longer than that[(13.00 ± 4.01)d]in the control group(t=29.473,P <0.001).Compared with non-stress hyperglycemia,stress hyperglycemia posed a higher risk of CAUTI in the stroke patients with indwelling catheter(OR=2.020,95% CI=1.447-2.821,P=0.000)and led to the higher incidence of CAUTI in one thousand days(P<0.001). Conclusion Stress hyperglycemia in the stroke patients with indwelling catheter can significantly increase the risk of CAUTI.

Immunogenicity and safety of a recombinant fusion protein vaccine (V-01) against coronavirus disease 2019 in healthy adults: a randomized, double-blind, placebo-controlled, phase II trial / 中华医学杂志(英文版)

BACKGROUND@#Innovative coronavirus disease 2019 (COVID-19) vaccines, with elevated global manufacturing capacity, enhanced safety and efficacy, simplified dosing regimens, and distribution that is less cold chain-dependent, are still global imperatives for tackling the ongoing pandemic. A previous phase I trial indicated that the recombinant COVID-19 vaccine (V-01), which contains a fusion protein (IFN-PADRE-RBD-Fc dimer) as its antigen, is safe and well tolerated, capable of inducing rapid and robust immune responses, and warranted further testing in additional clinical trials. Herein, we aimed to assess the immunogenicity and safety of V-01, providing rationales of appropriate dose regimen for further efficacy study.@*METHODS@#A randomized, double-blind, placebo-controlled phase II clinical trial was initiated at the Gaozhou Municipal Centre for Disease Control and Prevention (Guangdong, China) in March 2021. Both younger (n = 440; 18-59 years of age) and older (n = 440; ≥60 years of age) adult participants in this trial were sequentially recruited into two distinct groups: two-dose regimen group in which participants were randomized either to follow a 10 or 25 μg of V-01 or placebo given intramuscularly 21 days apart (allocation ratio, 3:3:1, n = 120, 120, 40 for each regimen, respectively), or one-dose regimen groups in which participants were randomized either to receive a single injection of 50 μg of V-01 or placebo (allocation ratio, 3:1, n = 120, 40, respectively). The primary immunogenicity endpoints were the geometric mean titers of neutralizing antibodies against live severe acute respiratory syndrome coronavirus 2, and specific binding antibodies to the receptor binding domain (RBD). The primary safety endpoint evaluation was the frequencies and percentages of overall adverse events (AEs) within 30 days after full immunization.@*RESULTS@#V-01 provoked substantial immune responses in the two-dose group, achieving encouragingly high titers of neutralizing antibody and anti-RBD immunoglobulin, which peaked at day 35 (161.9 [95% confidence interval [CI]: 133.3-196.7] and 149.3 [95%CI: 123.9-179.9] in 10 and 25 μg V-01 group of younger adults, respectively; 111.6 [95%CI: 89.6-139.1] and 111.1 [95%CI: 89.2-138.4] in 10 and 25 μg V-01 group of older adults, respectively), and remained high at day 49 after a day-21 second dose; these levels significantly exceed those in convalescent serum from symptomatic COVID-19 patients (53.6, 95%CI: 31.3-91.7). Our preliminary data show that V-01 is safe and well tolerated, with reactogenicity predominantly being absent or mild in severity and only one vaccine-related grade 3 or worse AE being observed within 30 days. The older adult participants demonstrated a more favorable safety profile compared with those in the younger adult group: with AEs percentages of 19.2%, 25.8%, 17.5% in older adults vs. 34.2%, 23.3%, 26.7% in younger adults at the 10, 25 μg V-01 two-dose group, and 50 μg V-01 one-dose group, respectively.@*CONCLUSIONS@#The vaccine candidate V-01 appears to be safe and immunogenic. The preliminary findings support the advancement of the two-dose, 10 μg V-01 regimen to a phase III trial for a large-scale population-based evaluation of safety and efficacy.@*TRIAL REGISTRATION@#http://www.chictr.org.cn/index.aspx (No. ChiCTR2100045107, http://www.chictr.org.cn/showproj.aspx?proj=124702).

The analysis of the long-term impact of SARS-CoV-2 on the cellular immune system in individuals recovering from COVID-19 reveals a profound NKT cell impairment

The coronavirus disease 2019 (COVID-19) pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) affects millions of people and killed hundred-thousands of individuals. While acute and intermediate interactions between SARS-CoV-2 and the immune system have been studied extensively, long-term impacts on the cellular immune system remained to be analyzed. Here, we comprehensively characterized immunological changes in peripheral blood mononuclear cells in 49 COVID-19 convalescent individuals (CI) in comparison to 27 matched SARS-CoV-2 unexposed individuals (UI). Despite recovery from the disease for more than 2 months, CI showed significant decreases in frequencies of invariant NKT and NKT-like cells compared to UI. Concomitant with the decrease in NKT-like cells, an increase in the percentage of Annexin V and 7-AAD double positive NKT-like cells was detected, suggesting that the reduction in NKT-like cells results from cell death months after recovery. Significant increases in regulatory T cell frequencies, TIM-3 expression on CD4 and CD8 T cells, as well as PD-L1 expression on B cells were also observed in CI, while the cytotoxic potential of T cells and NKT-like cells, defined by GzmB expression, was significantly diminished. However, both CD4 and CD8 T cells of CI showed increased Ki67 expression and were fully capable to proliferate and produce effector cytokines upon TCR stimulation. Collectively, we provide the first comprehensive characterization of immune signatures in patients recovering from SARS-CoV-2 infection, suggesting that the cellular immune system of COVID-19 patients is still under a sustained influence even months after the recovery from disease.

SARS-CoV-2 infection induces sustained humoral immune responses in convalescent patients following symptomatic COVID-19

Long-term antibody responses and neutralizing activities following SARS-CoV-2 infections have not yet been elucidated. We quantified immunoglobulin M (IgM) and G (IgG) antibodies recognizing the SARS-CoV-2 receptor-binding domain (RBD) of the spike (S) or the nucleocapsid (N) protein, and neutralizing antibodies during a period of six months following COVID-19 disease onset in 349 symptomatic COVID-19 patients, which were among the first world-wide being infected. The positivity rate and magnitude of IgM-S and IgG-N responses increased rapidly. High levels of IgM-S/N and IgG-S/N at 2-3 weeks after disease onset were associated with virus control and IgG-S titers correlated closely with the capacity to neutralize SARS-CoV-2. While specific IgM-S/N became undetectable 12 weeks after disease onset in most patients, IgG-S/N titers showed an intermediate contraction phase, but stabilized at relatively high levels over the six months observation period. At late time points the positivity rates for binding and neutralizing SARS-CoV-2-specific antibodies was still over 70%. Taken together, our data indicate sustained humoral immunity in recovered patients who suffer from symptomatic COVID-19, suggesting prolonged immunity.

Blockade of Adenosine A2b Receptor Reduces Tumor Growth and Migration in Renal Cell Carcinoma.

Adenosine A2b receptor (A2bR) is a member of the G protein-coupled receptor superfamily members, which has been considered involved in the pathogenesis of various cancers. However, little is known about the role of A2bR renal cell carcinoma (RCC). The A2bR expression levels in RCC 769-P and Caki-1 cell lines compared with HK-2 were analyzed by qRT-PCR. 769-P and Caki-1 cells were transfected with shRNA-A2bR to knock down the expression of A2bR. Cell proliferation was detected by MTT assays and colony formation assays. Wounding healing assays and transwell assays were used to evaluate the effects of A2bR on cell capacity of invasion and migration. Finally, potential mechanisms involved in A2bR blockade's effects on altered tumor behaviors were evaluated by western blotting. We showed that A2bR were significantly up-regulated in RCC cells compared to HK-2 cell. Functionally, MRS1754, a selective A2bR antagonist, and knocking-down the expression of A2bR by shRNA reduced proliferation and migration in vitro and tumor growth in vivo. Furthermore, we demonstrated that A2bR blockade inhibited tumor progression in part via the MAPK/JNK pathway. Conclusion: Our findings suggest the A2bR potentially plays an important role in RCC progression and A2bR blockade may be a promising candidate for therapeutic intervention for renal cell carcinoma.

Discovery of a novel coronavirus associated with the recent pneumonia outbreak in humans and its potential bat origin

Since the SARS outbreak 18 years ago, a large number of severe acute respiratory syndrome related coronaviruses (SARSr-CoV) have been discovered in their natural reservoir host, bats1-4. Previous studies indicated that some of those bat SARSr-CoVs have the potential to infect humans5-7. Here we report the identification and characterization of a novel coronavirus (nCoV-2019) which caused an epidemic of acute respiratory syndrome in humans, in Wuhan, China. The epidemic, started from December 12th, 2019, has caused 198 laboratory confirmed infections with three fatal cases by January 20th, 2020. Full-length genome sequences were obtained from five patients at the early stage of the outbreak. They are almost identical to each other and share 79.5% sequence identify to SARS-CoV. Furthermore, it was found that nCoV-2019 is 96% identical at the whole genome level to a bat coronavirus. The pairwise protein sequence analysis of seven conserved non-structural proteins show that this virus belongs to the species of SARSr-CoV. The nCoV-2019 virus was then isolated from the bronchoalveolar lavage fluid of a critically ill patient, which can be neutralized by sera from several patients. Importantly, we have confirmed that this novel CoV uses the same cell entry receptor, ACE2, as SARS-CoV.

Expression and antibody preparation of recombinant truncated glycoprotein of Guertu virus / 中华微生物学和免疫学杂志

Objective:To express truncated glycoprotein (Gn, Gn1, Gn2, Gn3, Gc1 and Gc2) of Guertu virus (GTV) in Escherichia coli ( E. coli) cells, and prepare polyclonal antibodies against recombinant proteins Gn-His, Gc1-His and Gc2-His after purification. Methods:Gene fragments encoding Gn, Gn1, Gn2, Gn3, Gc1 and Gc2 of GTV DXM strain were amplified by RT-PCR, and cloned into the prokaryotic expression vector pET-32a (+ ) to construct recombinant expression plasmids. The transformed E. coli BL21(DE3) strains carrying expression plasmids were induced by IPTG to express target proteins, which were identified by SDS-PAGE. Recombinant proteins Gn-His, Gc1-His and Gc2-His were purified by nickel affinity chromatography and detected by Western blot using GTV-positive sheep serum for analysis of their antigenicity. New Zealand white rabbits were immunized with the purified recombinant proteins. The titers and specificity of serum antibodies were analyzed by ELISA. Meanwhile, eukaryotic expression vectors pcDNA3.1-Gn, pcDNA3.1-Gc1/Gc2 were constructed and transfected into mammalian Vero cells to evaluate the binding activity of rabbit polyclonal antibodies by indirect immunofluorescence method. The specific reactivity of serum antibodies to recombinant proteins was detected by Western blot. Results:Restriction enzyme analysis and DNA sequencing confirmed that the recombinant expression vectors of pET-32a-Gn, pET-32a-Gn1/Gn2/Gn3, pET-32a-Gc1/Gc2, pcDNA3.1-Gn and pcDNA3.1-Gc1/Gc2 were constructed successfully. The relative molecular mass ( Mr) of the expressed recombinant proteins Gn-His, Gn1/Gn2/Gn3-His, Gc1/Gc2-His were approximately 63.4×10 3, 37.1×10 3, 31.9×10 3, 30.8×10 3, 40×10 3 and 54.4×10 3, respectively. The recombinant proteins could be recognized by GTV-positive sheep serum. The titers of polyclonal antibodies against GTV Gn, Gc1 and Gc2 were 1∶409 600, 1∶204 800 and 1∶6 400, respectively. Indirect immunofluorescence assay and Western blot showed that the prepared rabbit polyclonal antibodies could specifically react with the proteins expressed in eukaryotic cells and the recombinant proteins. Conclusions:The recombinant GTV glycoproteins Gn-His and Gc1/Gc2-His were efficiently expressed and purified and characterized with good immunity. The prepared polyclonal antibodies had high titers and good specificity. This study provided reference for further studying the biological function and detection methods of GTV glycoproteins and research on vaccines.

Application of Artificial Intelligence Automatic Diatom Identification System in Practical Cases / 法医学杂志

Objective To discuss the application of artificial intelligence automatic diatom identification system in practical cases, to provide reference for quantitative diatom analysis using the system and to validate the deep learning model incorporated into the system. Methods Organs from 10 corpses in water were collected and digested with diatom nitric acid; then the smears were digitally scanned using a digital slide scanner and the diatoms were tested qualitatively and quantitatively by artificial intelligence automatic diatom identification system. Results The area under the curve （AUC） of the receiver operator characteristic （ROC） curve of the deep learning model incorporated into the artificial intelligence automatic diatom identification system, reached 98.22% and the precision of diatom identification reached 92.45%. Conclusion The artificial intelligence automatic diatom identification system is able to automatically identify diatoms, and can be used as an auxiliary tool in diatom testing in practical cases, to provide reference to drowning diagnosis.

Relationship between Postmortem Interval and FTIR Spectroscopy Changes of the Rat Skin / 法医学杂志

Objective To infer postmortem interval （PMI） based on spectral changes of the dorsal skin of rats within 15 days postmortem using Fourier transform infrared （FTIR） spectroscopy. Methods The rats were sacrificed by cervical dislocation after anesthesia, and then placed at 25 ℃ and relative humidity of 50%. The FTIR spectral data collected from the dorsal skin at PMI points were modeled with machine learning technique. Results There was no significant difference of absorption peak location among all the PMI groups but their peak intensities changed as a function of PMIs. The model for PMI estimation was constructed using partial least squares （PLS） regression, reaching a R2 of 0.92 and a root mean square error （RMSE） of 1.30 d. As shown in variable importance for projection （VIP）, four spectral bands including 1 760-1 700 cm-1, 1 660-1 640 cm-1, 1 580-1 540 cm-1 and 1 460-1 420 cm-1 were determined as important contributions to model prediction. Conclusion Application of the FTIR technique to detect postmortem spectral changes of the rat skin provides a novel proposal for PMI estimation.

Determination of Electrocution Using Fourier Transform Infrared Microspectroscopy and Machine Learning Algorithm / 法医学杂志

Objective To analyze the differences among electrical damage, burns and abrasions in pig skin using Fourier transform infrared microspectroscopy （FTIR-MSP） combined with machine learning algorithm, to construct three kinds of skin injury determination models and select characteristic markers of electric injuries, in order to provide a new method for skin electric mark identification. Methods Models of electrical damage, burns and abrasions in pig skin were established. Morphological changes of different injuries were examined using traditional HE staining. The FTIR-MSP was used to detect the epidermal cell spectrum. Principal component method and partial least squares method were used to analyze the injury classification. Linear discriminant and support vector machine were used to construct the classification model, and factor loading was used to select the characteristic markers. Results Compared with the control group, the epidermal cells of the electrical damage group, burn group and abrasion group showed polarization, which was more obvious in the electrical damage group and burn group. Different types of damage was distinguished by principal component and partial least squares method. Linear discriminant and support vector machine models could effectively diagnose different damages. The absorption peaks at 2 923 cm-1, 2 854 cm-1, 1 623 cm-1, and 1 535 cm-1 showed significant differences in different injury groups. The peak intensity of electrical injury's 2 923 cm-1 absorption peak was the highest. Conclusion FTIR-MSP combined with machine learning algorithm provides a new technique to diagnose skin electrical damage and identification electrocution.

Higenamine alleviates cerebral ischemia-reperfusion injury in rats.

Cerebral ischemia reperfusion (I/R) injury is associated with a high incidence of neurological morbidity and mortality worldwide. Higenamine has anti-inflammatory, anti-oxidative and anti-apoptotic capacities and has been successfully used in myocardial and intestinal ischemia reperfusion. We hypothesized that higenamine might serve the same effects in cerebral I/R. In a rat model of cerebral I/R, higenamine improved functional state of nerves, significantly inhibited the I/R-induced increase in the serum level of tumor necrosis factor α (TNF-alpha) and interleukins (ILs) such as IL-1, IL-6 and IL-18, and CD14+ cells, while decreasing the axonal nerve degeneration. Together, the data demonstrate that higenamine has therapeutic effect in cerebral I/R injury.