OBJECTIVE: To investigate the effect of irradiation dose rate of ⁶⁰Co γ-ray on hematopoietic and immune cells in total body irradiation (TBI) mice. METHODS: After TBI with 8 Gy ⁶⁰Co γ-ray at three irradiation dose rates of 0.027, 0.256 and 0.597 Gy/min, the survival and change of body weight of C57BL/6J mice were observed within 30 days. The peripheral blood parameters were examined at each time point within 30 days post-irradiation. The hematopoietic stem/progenitor cell counts of mice were examined on the 10^th and 30^th day post-irradiation by flow cytometry, as well as the proportions of immune cells in peripheral blood, bone marrow and spleen of mice on the 30^th day post-irradiation. RESULTS: After TBI with 8 Gy ⁶⁰Co γ-ray, the 30-day survival rate of high dose-rate group was 0, which was significantly lower than 90% of medium dose-rate group and 100% of low dose-rate group (both P < 0.001). The peripheral blood parameters of all three groups showed a sharp decline → low value → gradually recovering trend. The count of white blood cell, neutrophil, lymphocyte, red blood cell, platelet and hemoglobin level in the high dose-rate and medium dose-rate groups were significantly lower than those in the low dose-rate group on day 7-18 post-irradiation (all P < 0.05), but there were no significant differences between the high dose-rate and medium dose-rate groups (P >0.05). On the 10^th day after irradiation, the proportion and number of bone marrow hematopoietic stem/progenitor cells (including LK, LSK, LT-HSC, ST-HSC, and MPP cells) in the low dose-rate and medium dose-rate groups were significantly decreased compared to those in the normal group (all P < 0.05), but there were no significant differences between the two groups (P >0.05). On the 30^th day after irradiation, LSK, LT-HSC, ST-HSC and MPP cells in the low dose-rate group recovered to normal levels, while those in the medium dose-rate group were still significantly lower than those in the low dose-rate group (all P < 0.001). The results of bone marrow and peripheral immune cell tests on the 30^th day after irradiation showed that the ratios of T and B lymphocytes in the low dose-rate and medium dose-rate groups were reduced compared to that in the normal group (both P < 0.05), while the ratio of neutrophils was increased (P < 0.01). The trend of changes in the spleen and peripheral blood was consistent. CONCLUSION The degree of hematopoietic and immune cell damage in mice after TBI with 8 Gy ⁶⁰Co γ-ray is related to the dose rate, and low dose-rate irradiation can reduce the damage in the animal model. Therefore, choosing the appropriate dose rate of irradiation is a key factor in establishing an objective and reliable experimental animal model of irradiation.
Animals ; Mice ; Whole-Body Irradiation ; Gamma Rays ; Mice, Inbred C57BL ; Hematopoietic Stem Cells/radiation effects* ; Cobalt Radioisotopes ; Dose-Response Relationship, Radiation ; Male

Abstract: Objective　To analyze the nucleic acid detection results of severe acute respiratory syndrome corona virus-2 (SARS-CoV-2) by droplet digital PCR (ddPCR) and compare with the detection results of real-time fluorescence quantitative RT-PCR (qRT-PCR), so as to evaluate the advantages and disadvantages of detection, and to provide data support for optimizing the nucleic acid detection scheme of SARS-CoV-2. Methods　According to the SARS-CoV-2 specific primer probe published by the China Center for Disease Control and Prevention, a ddPCR detection method for SARS-CoV-2 was designed. One sample was selected for sensitivity test after gradient dilution; six respiratory virus nucleic acid positive samples including seasonal H3N2 influenza virus and SARS-CoV-2 positive samples were selected for specificity test; five SARS-CoV-2 positive samples were selected for repeatability test; in addition, 30 positive and 20 negative SARS-CoV-2 samples were selected for multiple clinical samples testing, and the results were analyzed and compared with those of qRT-PCR. Results　The ddPCR method can specifically detect SARS-CoV-2, and directly obtain the original copy number of the sample target gene to achieve accurate quantification; the sensitivity test of gradient dilution positive samples showed that qRT-PCR detected target genes in part of the 10-5 dilution of samples, and no target genes were detected in 10-6 dilution, while ddPCR detected all target genes in both 10-5 and 10-6 dilution of samples. The detection limit of ddPCR was two orders of magnitude higher than that of qRT-PCR, and the sensitivity was higher than that of qRT-PCR; in the comparison of the repeatability test results of the two methods, the coefficient of variation of ddPCR was 1.266%-11.814%, lower than 1.729%-26.174% of qRT PCR, and the repeatability was higher than qRT-PCR; among 50 clinical samples, 30 positive samples of confirmed cases of Coronavirus Disease 2019 (COVID-19) were detected by both methods, SARS-CoV-2 was successfully detected by both methods, and 20 negative samples of COVID-19 were detected by both methods, and the results were negative, with a coincidence rate of 100.00% (50/50). Conclusion　The ddPCR method can accurately quantify SARS-CoV-2 with strong specificity, and its sensitivity and repeatability are higher than those of qRT-PCR, but it also has certain detection limitations and is more suitable for the detection of low load samples. In the actual detection, the two methods can be reasonably combined to improve the detection accuracy.

OBJECTIVE: To investigate the effect and relative mechanism of Recombinant Human Thrombopoietin (rhTPO) on long-term hematopoietic recovery in mice with acute radiation sickness. METHODS: Mice were intramuscularly injected with rhTPO (100 μg/kg) 2 hours after total body irradiation with ⁶⁰Co γ-rays (6.5 Gy). Moreover, six months after irradiation, peripheral blood, hematopoietic stem cells (HSC) ratio, competitive transplantation survival rate and chimerization rate, senescence rate of c-kit⁺ HSC, and p16 and p38 mRNA expression of c-kit⁺ HSC were detected. RESULTS: Six months after 6.5 Gy γ-ray irradiation, there were no differences in peripheral blood white blood cells, red blood cells, platelets, neutrophils and bone marrow nucleated cells in normal group, irradiated group and rhTPO group (P>0.05). The proportion of hematopoietic stem cells and multipotent progenitor cells in mice of irradiated group was significantly decreased after irradiation (P<0.05), but there was no significant changes in rhTPO group (P>0.05). The counts of CFU-MK and BFU-E in irradiated group were significantly lower than that in normal group, and rhTPO group was higher than that of the irradiated group(P<0.05). The 70 day survival rate of recipient mice in normal group and rhTPO group was 100%, and all mice died in irradiation group. The senescence positive rates of c-kit⁺ HSC in normal group, irradiation group and rhTPO group were 6.11%, 9.54% and 6.01%, respectively (P<0.01). Compared with the normal group, the p16 and p38 mRNA expression of c-kit⁺ HSC in the irradiated mice were significantly increased (P<0.01), and it was markedly decreased after rhTPO administration (P<0.01). CONCLUSION The hematopoietic function of mice is still decreased 6 months after 6.5 Gy γ-ray irradiation, suggesting that there may be long-term damage. High-dose administration of rhTPO in the treatment of acute radiation sickness can reduce the senescence of HSC through p38-p16 pathway and improve the long-term damage of hematopoietic function in mice with acute radiation sickness.
Humans ; Mice ; Animals ; Thrombopoietin/metabolism* ; Hematopoietic Stem Cells ; Blood Platelets ; Recombinant Proteins/therapeutic use* ; Radiation Injuries ; RNA, Messenger/metabolism*

OBJECTIVE: To study the effect of interleukin-6 (IL-6) gene deletion on radiation-induced hematopoietic injury in mice and relative mechanism. METHODS: Before and after whole body ⁶⁰Co γ-ray irradiation, it was analyzed and compared that the difference of peripheral hemogram, bone marrow hematopoietic stem and progenitor cells conts in IL-6 gene knockout (IL-6^-/-) and wild-type (IL-6^+/+) mice and serum IL-6 and G-CSF expression levels in above- mentioned mouse were detected. Moreover, 30 days survival rate of IL-6^-/- and IL-6^+/+ mice after 8.0 Gy γ-ray irradiation were analyzed. RESULTS: IL-6 levels in serum of IL-6^+/+ and IL-6^-/- mice were respectively (98.95±3.85) pg/ml and (18.36±5.61) pg/ml, which showed a significant statistical differences (P<0.001). There were no significant differences of peripheral blood cell counts and G-CSF level in serum between IL-6^+/+ and IL-6^-/- mice before irradiation (P>0.05). However, the number of leukocytes, neutrophils, lymphocytes, monocytes, platelets in peripheral blood and G-CSF level in serum of IL-6^-/- mice were significantly decreased at 6 h after 8.0 Gy γ-ray irradiation compared with that of IL-6^+/+ mice. On days 30 after 8.0 Gy γ-ray irradiation, the survival rate of IL-6^+/+ and IL-6^-/- mice was 62.5% and 12.5%, and the mean survival time of dead mice was 16.0±1.0 and 10.6±5.3 days, respectively. On days 14 after 6.5 Gy γ-ray irradiation, bone marrow nucleated cells in IL-6^+/+ and IL-6^-/- mice were respectively (10.0±1.2)×10⁶ and (8.3±2.2)×10⁶ per femur. Compared with IL-6^+/+ mice, the proportion of Lin^-Sca-1^-c-kit⁺ (LK) in bone marrow of IL-6^-/- mice had no significant change (P>0.05), but the proportion of Lin^-Sca-1⁺c-kit⁺ (LSK) was significantly decreased (P<0.05). CONCLUSION IL-6 plays an obvious role in regulating hematopoietic radiation injury, and IL-6 deficiency can inhibit the radiation-induced increase of endogenous G-CSF level in serum, aggravates the damage of mouse hematopoietic stem cells（HSC） and the reduction of mature blood cells in peripheral blood caused by ionizing irradiation, resulting in the shortening of the survival time and significant decrease of the survival rate of mice exposed to lethal dose radiation.
Animals ; Gene Deletion ; Granulocyte Colony-Stimulating Factor/pharmacology* ; Interleukin-6/metabolism* ; Mice ; Radiation Injuries ; Whole-Body Irradiation

OBJECTIVE: To investigate the effect of atovaquone on the cell cycle and apoptosis of non-Hodgkin's lymphoma Raji cells, and clarify the related mechanisms. METHODS: MTT assay and trypan blue dye exclusion method were used to evaluate the effect of atovaquone on the proliferation of Raji cells. After the cells were stained by PI staining, the cell cycle distribution was detected by flow cytometry. Cell apoptosis was analyzed by Annexin V/PI double binding assay. The intracellular alterations of reactive oxygen species were detected by 2', 7'-dichlorofluorescein diacetate (DCFH-DA). The protein expression of cell cycle and apoptosis related molecules were detected by Western blot. RESULTS: Various concentrations of atovaquone (5-40 μmol/L) inhibited the growth of Raji cells in a concentration-dependent manner (r=0.951). The proliferation of Raji cells was significantly inhibited after treated by atovaquone (20 and 30 μmol/L) for 24, 48 and 72 h, which showed statistically different with that in the control group (P<0.01, P<0.001, P<0.001). G₁ phase arrest (P<0.01, P<0.001) and apoptosis (P<0.01) of Raji cells was induced by atovaquone (20 and 30 μmol/L) significantly for 24 h and 48 h, respectively. The expression of p-JAK2 and p-STAT3(Y705) protein were down-regulated significantly induced by atovaquone (P<0.001, P<0.05). Furthermore, atovaquone treatment could induce the decreasing of antiapoptotic protein Mcl-1, Bcl-2, and Bcl-xl expression level (P<0.05) and increasing of cleaved caspase-3 protein expression level. In addition, atovaquone could also induce the down-regulation of c-Myc (P<0.001, P<0.01) and cell cycle related molecules Cyclin D1, CDK4, and CDK6 (P<0.01, P<0.05) protein expression. CONCLUSION Atovaquone effectively inhibits cell proliferation and induces cell cycle arrest and apoptosis by suppression of STAT3 signaling pathway in Raji cells. It can be a potential therapeutic agent against non-Hodgkin's lymphoma.
Humans ; Atovaquone/pharmacology* ; Cell Cycle Checkpoints ; Apoptosis ; Lymphoma, Non-Hodgkin

OBJECTIVE: To confirm the therapeutic effect of recombinant human thrombopoietin (rhTPO) on rhesus monkeys irradiated with 5.0 Gy ⁶⁰Co γ-ray, and provide experimental basis for clinical treatment of similar patients. METHODS: Fourteen adult rhesus monkeys were irradiated with ⁶⁰Co γ-ray on both sides at the dose of 5.0 Gy (dose rate 69.2 cGy/min) to establish the acute radiation sickness model. The monkeys were divided into irradiation group (n=5), rhTPO 5 μg/kg group (n=4) and rhTPO 10 μg/kg group (n=5). Two hours after irradiation, the three groups of monkeys were injected with saline 0.1 ml/kg, rhTPO 5 μg/kg（0.1 ml/kg） and rhTPO 10 μg/kg(0.2 ml/kg), respectively. The general signs, survival, peripheral hemogram and serum biochemistry of rhesus monkeys were observed before and after irradiation, and the differences between rhTPO group and irradiation control group were compared. RESULTS: After total body irradiation with 5.0 Gy⁶⁰Co γ-ray, rhesus monkeys successively showed fever, hemorrhage, sharp decrease of whole blood cell counts in peripheral blood and disorder of serum biochemical indexes. Compared with the irradiated control group, a single intramuscular injection of rhTPO 5 μg/kg or 10 μg/kg 2 hours after irradiation could improve the symptoms of fever and bleeding, increase the nadir of peripheral red blood cells and platelets counts, shorten the duration of hemocytopenia, and advance the time for blood cells to return to the pre-irradiation level. The serum biochemical results showed that rhTPO could improve the abnormality of serum biochemical indexes in rhesus monkeys induced by 5.0 Gy total body irradiation to some extent. Compared with the two administration groups, the therapeutic effect of rhTPO 10 μg/ kg was better. CONCLUSION A single injection of rhTPO 5 μg/ kg or 10 μg/ kg 2 hours after irradiation can alleviate the injury of multilineage hematopoiesis and promote the recovery in monkeys irradiated by 5.0 Gy γ-ray. It also improves animal signs and has obvious therapeutic effect on acute radiation sickness.
Humans ; Animals ; Macaca mulatta ; Radiation Injuries

Objective : To explore the relationship between geriatric nutritional risk index( GNRI) and perioperative nutritional status，postoperative recovery and complications in elderly patients with gastric cancer． Methods : In this retrospective study，212 elderly patients ( aged ≥60 years ) with gastric cancer who underwent gastrectomy were recruited．GNRI was used to retrospectively assess the patients' preoperative nutritional status ，and analyze the relationship between GNRI and perioperative nutritional status，postoperative recovery and complications．The ROC curve was applied to explore the value of GNRI in predicting postoperative complications. Results : The inci- dence of preoperative nutritional risk in elderly patients undergoing gastric cancer surgery was 45. 07%．Compared with the patients whose GNRI＞98 points，the patients whose GNRI≤98 points had different degrees of decrease in serum total protein，albumin，prealbumin，hemoglobin and lymphocyte counts before surgery，day 1 and day 5－8 after surgery (P ＜0. 05) ．The patients whose GNRI ＜92 points had longer postoperative hospital stay than those with GNRI＞98 points (P＜0. 05) ．With the decrease of GNRI scores，the incidence of complications showed an upward trend(P＜0. 001) ．The multivariate analysis of the relationship between GNRI and postoperative complica- tions showed that TNM staging of III －IV and GNRI ＜92 points were independent risk factors for complications. GNRI had a good predictive value for the occurrence of complications (AUC = 0. 639，95% CI : 0. 570－0. 703，P = 0. 001，Cut-off value : 92. 21) ． Conclusion GNRI can be used for preoperative nutritional assessment for eld- erly gastric cancer patients．Patients with GNRI＜92. 21 points should be actively given nutritional therapy to im- prove perioperative nutritional status，speed up postoperative recovery，and reduce the occurrence of complications.

OBJECTIVE: To establish a leukemia mouse model induced by transplantation of hematopoietic cells from mixed lineage leukemia (MLL)-AF9 transgenic mice so as to provide the basis for the mechanism research and drug screening of acute myeloid leukemia (AML). METHODS: MLL-AF9 knock-in mice were bred and identified. When the mice developed leukemia, white blood cell (WBC) count in peripheral blood, flow cytometry and morphology method were analyzed to identify the disease. When the WBC count in peripheral blood was more than 100×10 RESULTS: The natural onset times of leukemia on MLL-AF9 knock-in mice were 22-28 weeks. The spleens of the transgenic mice enlarged and the bone marrow showed the immature forms of myeloid leukemia cells. Both the bone marrow and spleen cells highly expressed myeloid markers, CD11b and Gr-1. At least 0.5×10 CONCLUSION The leukemia model of hematopoietic cell transplantation based on MLL-AF9 transgenic mice is successfully established, which can be used for the study of the pathogenesis and evaluation of therapeutic effect of AML.
Animals ; Hematopoietic Stem Cell Transplantation ; Leukemia, Myeloid, Acute ; Mice ; Mice, Inbred C57BL ; Mice, Transgenic ; Oncogene Proteins, Fusion

Objective: This aim of the study is to analyze the general and specific inhibition control of college students who have mobile phone dependence and their craving for mobile phone after the wastage of inhibition control resource, and to provide a reference for the intervention. Methods: The Mobile Phone Addiction Tendency Scale was used to screen 40 mobile phone dependence and 40 non-dependence college students, who were divided into two groups completed two conditions of Numerical Stroop Task with and without mobile phone ringing sound interference. Craving for mobile phone before and after the Numerical Stroop Task was assessed. Results: Mobile phone dependence group had significantly more Stroop interference scores than mobile phone normal use group under the two conditions( F =19.34, P <0.01).After completing the Numerical Stroop Task under the interference condition, mobile phone dependence group experienced a significant boost craving of mobile phone ( t =-6.02, P <0.01). The scores of craving for mobile phones after the Numerical Stroop Task had significant positive relationships with Stroop interference scores( r =0.51, 0.51 , P <0.05). Conclusion The mobile phone dependence college students have poor inhibition control, inhibitory control which might associate with increase of craving for mobile phone.

Objective:Compare the effects of 3 administration methods (tracheal perfusion, tail vein injection and aerosol inhalation) with bleomycin (BLM) in inducing pulmonary fibrosis in rats, in order to find out the optimal administration methods. Method:Eighty sprague-dawley (SD) male rats with SPF were randomly divided into aerosol inhalation blank group, single tracheal perfusion group(10 mg·kg^-1), multiple tracheal perfusion group(5 mg·kg^-1), single intravenous injection group(150 mg·kg^-1), multiple intravenous injection group(50 mg·kg^-1), single aerosol inhalation group (30 min)and multiple aerosol inhalation group(30 min). The mortality and body weight of rats in each group were observed at 7 d, 14 d and 28 d after the administration. And 28 days later after the administration, the lung coefficients of rats in each group were observed, paraffin sections were prepared, hematoxylin-eosin staining (HE) and Masson staining were performed, and the contents of hydroxyproline (HYP) and plasminogen activator inhibitor-1 (PAI-1) in lung tissues were detected by enzyme-linked immunosorbent assay (ELISA), so as to evaluate the alveoli inflammation and pulmonary fibrosis of rats in each group. Result:Compared with the aerosol inhalation blank group, the rats in the trachea perfusion group had the highest mortality among the drug treatment groups. The pulmonary coefficients of rats in the multiple intravenous injection group and the multiple inhalation group were significantly higher than those in the blank group(P<0.05,P<0.01). The multiple inhalation group was higher than the other model group and the single atomization model group. The results of HE and Masson staining showed thickening of pulmonary septum and higher degree of pulmonary interstitial fibrosis in tracheal perfusion group, intravenous injection group and multiple inhalation group. The degree of pulmonary fibrosis in the multiple inhalation group was more obvious than that in other groups. The results of ELISA showed that the levels of HYP and PAI-1 in lung tissues of rats in aerosol inhalation group and tracheal perfusion group were significantly higher than those in control group(P<0.05). The multiple inhalation group and the single atomization inhalation group were significantly higher than other modules. Conclusion:Bleomycin was inhaled repeatedly to establish pulmonary fibrosis model. The pathological injury and physiological indexes of the model rats were relatively stable, which conforms with the evolution process of pulmonary fibrosis.