1.Isolation,identification and antimicrobial susceptibility of a strain of Haemophi-lus parasuis
Xi LIU ; Geng WANG ; Zhengdan LIN ; Xiuxiu SUN ; Xinxin JIN ; Li LI ; Junjie YANG ; Xue-ying HU ; Changqin GU ; Wanpo ZHANG ; Xiaoli LIU ; Teng YU ; Guofu CHENG
Chinese Journal of Veterinary Science 2025;45(2):219-226
Porcine arthritis,one of the common chronic diseases in large-scale pig farms,can signifi-cantly reduce the production performance of meat pigs.In this study,a strain of Haemophilus pa-rasuis(HPS)was isolated from the joint fluid of a lame pig.The HPS was analyzed in terms of se-rotypes,virulence genes,and resistance genes.Additionally,it was treated with sensitive antibiotics to provide a theoretical basis for the comprehensive prevention and treatment of arthritis in meat pigs in future production settings.A strain of HPS type 14 was isolated from the joint fluid of dis-eased pigs.The HPS isolate demonstrated sensitivity to β-lactams and tetracyclines,while florfeni-col and polymyxin effectively inhibited its growth at low concentrations.However,the bacteria ex-hibited resistance to sulfonamides and ciprofloxacin.The treatment of affected pigs with clinical ar-thritis using doxycycline and enrofloxacin injections proved effective.Compared to the infected group,in which the sick pigs experienced difficulty flexing their carpal and tarsal joints and exhibi-ted significant lameness,the pigs in the treatment group showed marked improvement.Their joints were only slightly swollen,and the clinical symptoms of arthropathy were alleviated.
2.Research progress in protection against damage to cognitive function caused by microwave exposure
Menghua LI ; Xinyu WANG ; Guofu DONG ; Changzhen WANG
Military Medical Sciences 2025;49(10):791-796
With the rapid development and widespread application of microwave technology,people's lives and work have been made more convenient.However,the health of those who are constantly exposed to complex microwave environments is also threatened.In recent years,many studies have found that long-term exposure to micro waves can cause damage to cognitive function.However,the damage mechanism has not been fully understood.This article reviews the research progress of microwave radiation on cognitive function in recent years,the damage mechanism,and the related drugs for protection and treatment,in order to provide references for research in this field.
3.Mechanisms of FLASH irradiation on acute radiation-induced intestinal injury in mice
Xiaoman LIU ; Yani LIU ; Zhihui LI ; Dongfei YAN ; Lihui ZHANG ; Menghua LI ; Shaobin LI ; Guofu DONG ; Changzhen WANG
Chinese Journal of Radiological Medicine and Protection 2025;45(11):1085-1091
Objective:To explore differences in the radiation-induced intestinal injury in mice exposed to ultra-high dose rate (FLASH) and conventional-dose-rate (CONV) pulsed X-ray irradiation in order to provide evidence for the application of ultra-high dose rate pulsed X-rays in gastrointestinal radiotherapy.Methods:Using the random number table method, 32 C57BL/6J mice were randomly divided into four groups: a sham irradiation group (SHAM), two conventional dose rate groups (CONV0.067 and CONV0.1), and an ultra-high dose rate group (F215), with each group containing eight mice. All groups, except SHAM, received a single 12 Gy abdominal X-ray irradiation at dose rates of 0.067, 0.1, and 215 Gy/s, respectively. At 3 d post-irradiation, histopathological (hematoxylin-eosin staining, HE staining), immunohistochemical, and Western blot analysis were performed to assess the histopathological markers and oxidative stress indicators of intestinal tissues, as well as relevant proteins involved in signaling pathways.Results:At 3 d post-irradiation, mice in all irradiation groups suffered from varying degrees of intestinal tissue degeneration and necrosis, epithelial cell shedding, villus shortening, and crypt loss ( t = 5.75, 8.79, 5.71, P < 0.05). Regarding oxidative stress, at 3 d post-irradiation, mice in the CONV0.067 and CONV0.1 groups showed significantly lower levels of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-PX), glutathione (GSH), and total antioxidant capacity (T-AOC) compared to those in the F215 group ( t = 7.06-10.64, P < 0.01). In contrast, their malondialdehyde (MDA) levels were significantly elevated ( t = 11.06, 8.31, P < 0.01), with no statistical significance observed between them and mice in the F215 group ( P > 0.05). Immunohistochemical and Western blot analyses indicated that at 3 d post-irradiation, mice in the three irradiation groups exhibited an upward trend in the Nrf2 and HO-1 protein levels and a downward trend in the Keap1 protein level compared to those in the SHAM group. Notably, statistical significance was observed between the F215 group and the two conventional dose rate groups ( t = 4.89-20.95, P < 0.05). These result were consistent with the prior changes in antioxidant markers. Conclusions:Ultra-high-dose-rate X-ray irradiation reduces acute RIII by alleviating oxidative stress and modulating the expression of the Keap1-Nrf2-HO-1 signaling pathway.
4.A Geant4-based research on radiation field distribution in a 9 MeV e-FLASH treatment room
Deqi CHENG ; Qin YANG ; Xufan HUANG ; Peng WU ; Haoran XIE ; Jing XIA ; Erfeng WANG ; Guofu YU ; Yu JIANG ; Xianhong LIU
Chinese Journal of Radiological Medicine and Protection 2025;45(11):1152-1156
Objective:To investigate the radiation field distribution characteristics in a 9 MeV electron FLASH (e-FLASH) linear accelerator treatment room.Methods:The Geant4 Monte Carlo program was employed for physical simulating of the radiation field distribution inside and outside the treatment room under a single-beam delivery condition with a total dose of 50 Gy at the reference point and a dose rate of 250 Gy/s. High-sensitivity radiation detectors (AT1123) were used to validate the measurements at key points.Results:The dose rate at the reference point was approximately 9×10 11 μSv/h. Due to the scattering and shielding effects, the deviation of the attenuation rate from the inverse-square law was observed and the isodose lines exhibited spatial drift. Measured dose rates at key points showed good agreement with the simulation result, with a maximum deviation within 30%. Conclusions:The complex radiation field distribution can be effectively simulated using Geant4 in an e-FLASH treatment room. This indicated the Geant4 is not only applicable for the shielding calculations in e-FLASH radiotherapy facilities, but also for the design optimization through, reduction of trial-and-error iterations and engineering costs.
5.Mechanisms of FLASH irradiation on acute radiation-induced intestinal injury in mice
Xiaoman LIU ; Yani LIU ; Zhihui LI ; Dongfei YAN ; Lihui ZHANG ; Menghua LI ; Shaobin LI ; Guofu DONG ; Changzhen WANG
Chinese Journal of Radiological Medicine and Protection 2025;45(11):1085-1091
Objective:To explore differences in the radiation-induced intestinal injury in mice exposed to ultra-high dose rate (FLASH) and conventional-dose-rate (CONV) pulsed X-ray irradiation in order to provide evidence for the application of ultra-high dose rate pulsed X-rays in gastrointestinal radiotherapy.Methods:Using the random number table method, 32 C57BL/6J mice were randomly divided into four groups: a sham irradiation group (SHAM), two conventional dose rate groups (CONV0.067 and CONV0.1), and an ultra-high dose rate group (F215), with each group containing eight mice. All groups, except SHAM, received a single 12 Gy abdominal X-ray irradiation at dose rates of 0.067, 0.1, and 215 Gy/s, respectively. At 3 d post-irradiation, histopathological (hematoxylin-eosin staining, HE staining), immunohistochemical, and Western blot analysis were performed to assess the histopathological markers and oxidative stress indicators of intestinal tissues, as well as relevant proteins involved in signaling pathways.Results:At 3 d post-irradiation, mice in all irradiation groups suffered from varying degrees of intestinal tissue degeneration and necrosis, epithelial cell shedding, villus shortening, and crypt loss ( t = 5.75, 8.79, 5.71, P < 0.05). Regarding oxidative stress, at 3 d post-irradiation, mice in the CONV0.067 and CONV0.1 groups showed significantly lower levels of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-PX), glutathione (GSH), and total antioxidant capacity (T-AOC) compared to those in the F215 group ( t = 7.06-10.64, P < 0.01). In contrast, their malondialdehyde (MDA) levels were significantly elevated ( t = 11.06, 8.31, P < 0.01), with no statistical significance observed between them and mice in the F215 group ( P > 0.05). Immunohistochemical and Western blot analyses indicated that at 3 d post-irradiation, mice in the three irradiation groups exhibited an upward trend in the Nrf2 and HO-1 protein levels and a downward trend in the Keap1 protein level compared to those in the SHAM group. Notably, statistical significance was observed between the F215 group and the two conventional dose rate groups ( t = 4.89-20.95, P < 0.05). These result were consistent with the prior changes in antioxidant markers. Conclusions:Ultra-high-dose-rate X-ray irradiation reduces acute RIII by alleviating oxidative stress and modulating the expression of the Keap1-Nrf2-HO-1 signaling pathway.
6.A Geant4-based research on radiation field distribution in a 9 MeV e-FLASH treatment room
Deqi CHENG ; Qin YANG ; Xufan HUANG ; Peng WU ; Haoran XIE ; Jing XIA ; Erfeng WANG ; Guofu YU ; Yu JIANG ; Xianhong LIU
Chinese Journal of Radiological Medicine and Protection 2025;45(11):1152-1156
Objective:To investigate the radiation field distribution characteristics in a 9 MeV electron FLASH (e-FLASH) linear accelerator treatment room.Methods:The Geant4 Monte Carlo program was employed for physical simulating of the radiation field distribution inside and outside the treatment room under a single-beam delivery condition with a total dose of 50 Gy at the reference point and a dose rate of 250 Gy/s. High-sensitivity radiation detectors (AT1123) were used to validate the measurements at key points.Results:The dose rate at the reference point was approximately 9×10 11 μSv/h. Due to the scattering and shielding effects, the deviation of the attenuation rate from the inverse-square law was observed and the isodose lines exhibited spatial drift. Measured dose rates at key points showed good agreement with the simulation result, with a maximum deviation within 30%. Conclusions:The complex radiation field distribution can be effectively simulated using Geant4 in an e-FLASH treatment room. This indicated the Geant4 is not only applicable for the shielding calculations in e-FLASH radiotherapy facilities, but also for the design optimization through, reduction of trial-and-error iterations and engineering costs.
7.Isolation,identification and antimicrobial susceptibility of a strain of Haemophi-lus parasuis
Xi LIU ; Geng WANG ; Zhengdan LIN ; Xiuxiu SUN ; Xinxin JIN ; Li LI ; Junjie YANG ; Xue-ying HU ; Changqin GU ; Wanpo ZHANG ; Xiaoli LIU ; Teng YU ; Guofu CHENG
Chinese Journal of Veterinary Science 2025;45(2):219-226
Porcine arthritis,one of the common chronic diseases in large-scale pig farms,can signifi-cantly reduce the production performance of meat pigs.In this study,a strain of Haemophilus pa-rasuis(HPS)was isolated from the joint fluid of a lame pig.The HPS was analyzed in terms of se-rotypes,virulence genes,and resistance genes.Additionally,it was treated with sensitive antibiotics to provide a theoretical basis for the comprehensive prevention and treatment of arthritis in meat pigs in future production settings.A strain of HPS type 14 was isolated from the joint fluid of dis-eased pigs.The HPS isolate demonstrated sensitivity to β-lactams and tetracyclines,while florfeni-col and polymyxin effectively inhibited its growth at low concentrations.However,the bacteria ex-hibited resistance to sulfonamides and ciprofloxacin.The treatment of affected pigs with clinical ar-thritis using doxycycline and enrofloxacin injections proved effective.Compared to the infected group,in which the sick pigs experienced difficulty flexing their carpal and tarsal joints and exhibi-ted significant lameness,the pigs in the treatment group showed marked improvement.Their joints were only slightly swollen,and the clinical symptoms of arthropathy were alleviated.
8.Dosimetric study of isolated neuronal networks under 2.6 GHz radiofrequency exposure
Yuqing WANG ; Xuelong ZHAO ; Qi LIU ; Guofu DONG ; Yu WEI ; Ni CHEN ; Xiaoman LIU ; Changzhen WANG ; Hongmei ZHOU
Military Medical Sciences 2024;48(2):95-100
Objective To evaluate the characteristics of dose distribution of neuronal networks in vitro on microelectrode arrays(MEAs)under 2.6 GHz radiofrequency(RF)exposure.Methods The MEAs were coupled with a real-time RF exposure setup,and electromagnetic simulation software was used to calculate the RF dose absorbed in cultured neuronal networks.A fiber-optic temperature probe was used for experimental validation and monitoring of the cell temperature during RF exposure.The MEAs were used to record the electrical activity of neurons.Results For an input power of 1 W,a specific absorption rate(SAR)level of(15.51±2.48)W/kg was calculated,and the variability of the SAR distribution was 16%.In our experimental system,the temperature elevation of neurons was up to 0.15℃for an SAR of 4 W/kg RF exposure.Conclusion The exposure device can provide high SAR efficiency and uniformity in the 2.6 GHz band,which is suitable for studying the real-time effects of RF fields on the electrical activity of neuronal networks in the 5G network band.
9.Effects of pulsed electron beams with ultra-high dose rate and conventional dose rate on Caenorhabditis elegans
Shuang WU ; Zhihui LI ; Wenxi YANG ; Guofu DONG ; Changzhen WANG
Chinese Journal of Radiological Medicine and Protection 2024;44(11):903-908
Objective:To explore the effects of ultra-high dose rate pulsed electron beams on Caenorhabditis elegans ( C. elegans). Methods:The adult wild-type strain (N2) of C. elegans was synchronized and cultured to L4 stage, and then randomly divided into control group (SHAM group), conventional radiotherapy dose rate group (CONV group) and ultra-high dose rate radiation group (UHDR group). The CONV and UHDR groups were exposed to 3 Gy of the pulsed electron beam at dose rates of 0.3 and 200 Gy/s, respectively. After irradiation, the egg-laying capacity of each group was assessed, and the developmental progress, motility, and survival rates each were evaluated at day 3, 6, and 10. Results:On the 3 rd day post-irradiation, both the CONV and UHDR groups showed shorter body lengths compared to the SHAM group ( t=4.81, 4.83, P<0.05), with no significant differences in body width ( P>0.05). On the 6 th and 10 th days, the CONV group showed a significant reduction in both body length and width compared to the SHAM group ( t=3.18-3.63, P<0.05), whereas the UHDR group displayed a significant increase in body length ( t=-9.85, -2.87, P<0.05) with no significant change in body width. When comparing the UHDR group to the CONV group on day 6 and 10, a significant increase in body width was observed ( t=-4.43, -3.37, P<0.05). Motor activity, including head swinging and body bending, significantly decreased in the CONV and UHDR groups compared to the SHAM group on day 6 ( t=2.91, 3.52, 3.97, 2.71, P<0.05), with no significant differences among the three groups by day 10 ( P>0.05). Egg-laying capacity significantly reduced in both irradiated groups compared to the SHAM group ( t=1.72, 5.54, P<0.05), while the UHDR group exhibited higher fecundity than the CONV group ( t=-5.99, P<0.05). Lifespan was significantly shortened in the CONV group compared to the SHAM group ( χ2=8.49, P<0.05), whereas the survival time of the UHDR group was not significantly differ from that of the SHAM group ( P>0.05). Conclusions:Exposure to a conventional electron beam result in developmental delays, reduced mobility, decreased fecundity, and a shortened lifespan in C. elegans. However, only slight side effects were observed when C. elegans were exposed to an ultra-high dose rate pulsed electron beam at the same dosage.
10.Roles of Keap1-Nrf2 and NF-κB signaling pathways in lipopolysaccharide-induced brain injury
Yichen LIU ; Dongfei YAN ; Zhixin LI ; Yingchun MAO ; Zhihui LI ; Guofu DONG ; Changzhen WANG
Military Medical Sciences 2024;48(7):481-486
Objective To investigate the role of Kelch-like-epichlorohydrin-associated protein 1/nuclear factor erythroid-derived factor-2-related factor 2(Keap1-Nrf2)and nuclear factor-κB(NF-κB)signaling pathways in sepsis-associated encephalopathy(SAE).Methods Male C57BL/6J mice of SPF were randomly divided into four groups(n=10):the control group and LPS 6 h,24 h and 48 h groups.The behavioral changes of the mice were assessed based on their general conditions and open field test(OFT).ELISA was used to measure the levels of pro-inflammatory cytokines in mouse serum,and the antioxidant capacity assay kit to examine antioxidant activity in brain tissues of mice.Real-time quantitative PCR(qPCR)was adopted to detect the mRNA levels of toll-like receptor4(Tlr4),NF-κB,Keap1 and Nrf2 in the hippocampus,and to determine protein expressions of NF-κB a Nrf2、Keap1 and Tlr4 with Western blotting.Results Compared to the control group,the serum concentrations of interleukin 6(IL-6)in lipopolysaccharide(LPS)groups increased at 6 h,and reached the peak at 24 h and 48 h(P<0.01).The levels of serum interleukin 18(IL-18)in the LPS groups increased significantly at 6 h and 24 h(P<0.01)but there was no statistically significant difference compared with the 48h group.The results indicated the activity of superoxide dismutase(SOD)and glutathione(GSH)in brain tissues in LPS groups increased(P<0.01).OFT results showed the time spent in the center of the open field,the distance covered around the center,and total distance covered by mice in LPS groups were significantly reduced(P<0.01),except for the time spent in the center of the open field in the LPS 24 h group.The mRNA expressions of Tlr4 and(LPS 6 h,48 h)NF-κB in the hippocampus tissue of mice in LPS groups were elevated(P<0.05),so were the mRNA expressions of Keap1 and Nrf2 in LPS 6 h group.Additionally,the protein expressions of NF-κB,Keap1 and Tlr4 increased in LPS groups,so did the protein expression of Nrf2 in LPS 24 h and 48 h groups(P<0.05).Conclusion Keap1-Nrf2 and NF-κB signaling pathways may play a certain role in SAE.

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