1.The first record of Anopheles messeae (Diptera: Culicidae) parasitized by water mites in China
Xue-ru CHEN ; Wen-zhen YAO ; Yu-hao LI ; Gui-chang LI ; Tao MENG ; Qun-ling FENG ; Xin-hui LIU ; Li-hong QIAO ; Xiang-ting WU ; Xue-feng ZHANG ; Cheng-lin LI ; Xue-cheng DONG ; Da-wei WANG ; Xiao-yan SI ; Yu-hong GUO
Acta Parasitologica et Medica Entomologica Sinica 2026;33(1):53-57
Objective This study reports on the obligatory parasitism of water mites Arrenurus sp. on Anopheles messeae at the Manzhouli Port, Inner Mongolia, China. Methods Duing July 2024, a survey on the mosquito diversity was conducted at the Manzhouli Port. Captured mosquitoes and their ectoparasites were identified to species level. Results A total of 1840 adult mosquitoes were collected, representing species from three genera: Culex(Cx. modestus, Cx. pipiens pallens), Aedes(Ae. dorsalis, Ae. flavidorsalis, Ae. flavescens), and Anopheles (An. messeae). Among all the mosqutioes specimens,3 out of 150 captured An. messeae were found to carry ectoparasitic mites, with number of 2,4,27 mites separately. Morphological and molecular identification reached the same result as water mites(Hydrachnidiae, Hydracrina). COI gene sequence showed 94% similarity with the closest species Arrenurus truncatellus. Conlusions Literature review suggests water mites are host-specific parasitism of mosquito species and herein with the first record of Arrenurus sp. parasiting on An. Messeae in the most high-latitude region globally.
2.Acute Inflammatory Pain Induces Sex-different Brain Alpha Activity in Anesthetized Rats Through Optically Pumped Magnetometer Magnetoencephalography
Meng-Meng MIAO ; Yu-Xuan REN ; Wen-Wei WU ; Yu ZHANG ; Chen PAN ; Xiang-Hong LIN ; Hui-Dan LIN ; Xiao-Wei CHEN
Progress in Biochemistry and Biophysics 2025;52(1):244-257
ObjectiveMagnetoencephalography (MEG), a non-invasive neuroimaging technique, meticulously captures the magnetic fields emanating from brain electrical activity. Compared with MEG based on superconducting quantum interference devices (SQUID), MEG based on optically pump magnetometer (OPM) has the advantages of higher sensitivity, better spatial resolution and lower cost. However, most of the current studies are clinical studies, and there is a lack of animal studies on MEG based on OPM technology. Pain, a multifaceted sensory and emotional phenomenon, induces intricate alterations in brain activity, exhibiting notable sex differences. Despite clinical revelations of pain-related neuronal activity through MEG, specific properties remain elusive, and comprehensive laboratory studies on pain-associated brain activity alterations are lacking. The aim of this study was to investigate the effects of inflammatory pain (induced by Complete Freund’s Adjuvant (CFA)) on brain activity in a rat model using the MEG technique, to analysis changes in brain activity during pain perception, and to explore sex differences in pain-related MEG signaling. MethodsThis study utilized adult male and female Sprague-Dawley rats. Inflammatory pain was induced via intraplantar injection of CFA (100 μl, 50% in saline) in the left hind paw, with control groups receiving saline. Pain behavior was assessed using von Frey filaments at baseline and 1 h post-injection. For MEG recording, anesthetized rats had an OPM positioned on their head within a magnetic shield, undergoing two 15-minute sessions: a 5-minute baseline followed by a 10-minute mechanical stimulation phase. Data analysis included artifact removal and time-frequency analysis of spontaneous brain activity using accumulated spectrograms, generating spectrograms focused on the 4-30 Hz frequency range. ResultsMEG recordings in anesthetized rats during resting states and hind paw mechanical stimulation were compared, before and after saline/CFA injections. Mechanical stimulation elevated alpha activity in both male and female rats pre- and post-saline/CFA injections. Saline/CFA injections augmented average power in both sexes compared to pre-injection states. Remarkably, female rats exhibited higher average spectral power 1 h after CFA injection than after saline injection during resting states. Furthermore, despite comparable pain thresholds measured by classical pain behavioral tests post-CFA treatment, female rats displayed higher average power than males in the resting state after CFA injection. ConclusionThese results imply an enhanced perception of inflammatory pain in female rats compared to their male counterparts. Our study exhibits sex differences in alpha activities following CFA injection, highlighting heightened brain alpha activity in female rats during acute inflammatory pain in the resting state. Our study provides a method for OPM-based MEG recordings to be used to study brain activity in anaesthetized animals. In addition, the findings of this study contribute to a deeper understanding of pain-related neural activity and pain sex differences.
3.Verification of resveratrol ameliorating vascular endothelial damage in sepsis-associated encephalopathy through HIF-1α pathway based on network pharmacology and experiment.
Rong LI ; Yue WU ; Wen-Xuan ZHU ; Meng QIN ; Si-Yu SUN ; Li-Ya WANG ; Mei-Hui TIAN ; Ying YU
China Journal of Chinese Materia Medica 2025;50(4):1087-1097
This study aims to investigate the mechanism by which resveratrol(RES) alleviates cerebral vascular endothelial damage in sepsis-associated encephalopathy(SAE) through network pharmacology and animal experiments. By using network pharmacology, the study identified common targets and genes associated with RES and SAE and constructed a protein-protein interaction( PPI) network. Gene Ontology(GO) analysis and Kyoto Encyclopedia of Genes and Genomes(KEGG) pathway enrichment analysis were performed to pinpoint key signaling pathways, followed by molecular docking validation. In the animal experiments, a cecum ligation and puncture(CLP) method was employed to induce SAE in mice. The mice were randomly assigned to the sham group, CLP group, and medium-dose and high-dose groups of RES. The sham group underwent open surgery without CLP, and the CLP group received an intraperitoneal injection of 0. 9% sodium chloride solution after surgery. The medium-dose and high-dose groups of RES were injected intraperitoneally with 40 mg·kg-1 and 60 mg·kg~(-1) of RES after modeling, respectively, and samples were collected 12 hours later. Neurological function scores were assessed, and the wet-dry weight ratio of brain tissue was detected. Serum superoxide dismutase(SOD), catalase( CAT) activity, and malondialdehyde( MDA) content were measured by oxidative stress kit. Histopathological changes in brain tissue were examined using hematoxylin-eosin(HE) staining. Transmission electron microscopy was employed to evaluate tight cell junctions and mitochondrial ultrastructure changes in cerebral vascular endothelium. Western blot analysis was performed to detect the expression of zonula occludens1( ZO-1), occludin, claudins-5, optic atrophy 1( OPA1), mitofusin 2(Mfn2), dynamin-related protein 1(Drp1), fission 1(Fis1), and hypoxia-inducible factor-1α(HIF-1α). Network pharmacology identified 76 intersecting targets for RES and SAE, with the top five core targets being EGFR, PTGS2, ESR1, HIF-1α, and APP. GO enrichment analysis showed that RES participated in the SAE mechanism through oxidative stress reaction. KEGG enrichment analysis indicated that RES participated in SAE therapy through HIF-1α, Rap1, and other signaling pathways. Molecular docking results showed favorable docking activity between RES and key targets such as HIF-1α. Animal experiment results demonstrated that compared to the sham group, the CLP group exhibited reduced nervous reflexes, decreased water content in brain tissue, as well as serum SOD and CAT activity, and increased MDA content. In addition, the CLP group exhibited disrupted tight junctions in cerebral vascular endothelium and abnormal mitochondrial morphology. The protein expression levels of Drp1, Fis1, and HIF-1α in brain tissue were increased, while those of ZO-1, occludin, claudin-5, Mfn2, and OPA1 were decreased. In contrast, the medium-dose and high-dose groups of RES showed improved neurological function, increased water content in brain tissue and SOD and CAT activity, and decreased MDA content. Cell morphology in brain tissue, tight junctions between endothelial cells, and mitochondrial structure were improved. The protein expressions of Drp1, Fis1, and HIF-1α were decreased, while those of ZO-1, occludin, claudin-5, Mfn2, and OPA1 were increased. This study suggested that RES could ameliorate cerebrovascular endothelial barrier function and maintain mitochondrial homeostasis by inhibiting oxidative stress after SAE damage, potentially through modulation of the HIF-1α signaling pathway.
Animals
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Mice
;
Network Pharmacology
;
Resveratrol/administration & dosage*
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Male
;
Sepsis-Associated Encephalopathy/genetics*
;
Signal Transduction/drug effects*
;
Hypoxia-Inducible Factor 1, alpha Subunit/genetics*
;
Endothelium, Vascular/metabolism*
;
Molecular Docking Simulation
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Protein Interaction Maps/drug effects*
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Humans
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Sepsis/complications*
;
Oxidative Stress/drug effects*
4.Pharmacodynamics study and establishment of a PK-PD model for Epimedii Folium-Chuanxiong Rhizoma in treating osteoarthritis in rats.
En-Hui WU ; Jian-Hua ZHANG ; Wen-Jun CHEN ; Ya-Hong WANG ; Hua YIN
China Journal of Chinese Materia Medica 2025;50(5):1377-1384
This study aims to reveal the correlation between the pharmacokinetics(PK) and pharmacodynamics(PD) of multiple components in Epimedii Folium-Chuanxiong Rhizoma and clarify the pharmacodynamic material basis and mechanism of this herb pair in treating osteoarthritis. The Hulth method was used to establish the rat model of osteoarthritis and plasma was collected at various time points after drug administration. The plasma concentrations of multiple components were measured. Enzyme-linked immunosorbent assay(ELISA) was used to measure the plasma concentrations of matrix metalloproteinase(MMP)-3, MMP-13, interleukin-1β(IL-1β), nitric oxide(NO), and tumor necrosis factor-α(TNF-α) as pharmacodynamic indicators. Self-defined weighting coefficients were used to calculate the PK and PD data, and a Sigmoid E_(max) fitting model was used to evaluate the synergistic effect of the compatibility of Epimedii Folium-Chuanxiong Rhizoma. The PK-PD models for Epimedii Folium, Chuanxiong Rhizoma, and Epimedii Folium-Chuanxiong Rhizoma were E=(1.926×C~(2.652))/(0.136 6~(2.652)+C~(2.652)), E=(1.618×C~(345.2))/(0.118 4~(345.2)+C~(345.2)), and E=(2.305×C~(2.786))/(0.240 3~(2.786)+C~(2.786)), respectively. The E_(max) of Epimedii Folium-Chuanxiong Rhizoma was larger than those of the two herbal medicines alone. The EC_(50) of the herb pair was lower than the sum of Epimedii Folium and Chuanxiong Rhizoma alone. The concentrations of MMP-3, MMP-13, IL-1β, NO, and TNF-α were correlated with mass concentrations of multiple components in Epimedii Folium and Chuanxiong Rhizoma, and the compatibility was better than single use. Epimedii Folium, Chuanxiong Rhizoma, and Epimedii Folium-Chuanxiong Rhizoma may play a role in the treatment of osteoarthritis by inhibiting MMP-3, MMP-13, IL-1β, NO, and TNF-α.
Animals
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Rats
;
Drugs, Chinese Herbal/pharmacology*
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Male
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Rats, Sprague-Dawley
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Osteoarthritis/metabolism*
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Epimedium/chemistry*
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Interleukin-1beta/blood*
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Tumor Necrosis Factor-alpha/blood*
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Disease Models, Animal
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Nitric Oxide/blood*
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Humans
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Rhizome/chemistry*
5.Evaluation of nutritional value of three kinds of medicinal snakes based on content of 15 amino acids.
Xi WANG ; Ye-Yuan LIN ; Wen-Ting ZHONG ; Zhi-Guo MA ; Meng-Hua WU ; Hui CAO ; Ying ZHANG
China Journal of Chinese Materia Medica 2025;50(9):2411-2421
A high-performance liquid chromatography method using pre-column derivatization with 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate was developed to determine the content of 15 amino acids in the medicinal snakes Bungarus Parvus, Agkistrodon, and Zaocys. The results showed that the total amino acid(TAA) content ranged from 277.13 to 515.05 mg·g~(-1), with the top four amino acids in all three species being glutamic acid(Glu), glycine(Gly), aspartic acid(Asp), and lysine(Lys). The essential amino acid(EAA) content ranged from 74.56 to 203.94 mg·g~(-1), with Agkistrodon exhibiting the highest content. The non-essential amino acid(NEAA), semi-essential amino acid(semi-EAA), and medicinal amino acid(MAA) content ranged from 189.06 to 318.23, 12.89 to 33.53, and 179.83 to 342.33 mg·g~(-1), respectively, with Zaocys having the highest content in these categories. Amino acid nutritional value was evaluated using the amino acid ratio(RAA), amino acid ratio coefficient(RCAA), and amino acid ratio coefficient score(SRCAA), and the results indicated that all three medicinal snakes possessed good nutritional value. The amino acid composition was similar across the species, though significant differences in content were observed. Based on these differences, an orthogonal partial least squares-discriminant analysis(OPLS-DA) model was established, which could clearly distinguish between the three medicinal snake species. The key differences in amino acid content included Gly, tyrosine(Tyr), Glu, and serine(Ser), which may be related to the observed clinical application differences among the species. Further research into the mechanisms of these differential amino acids is expected to provide more insights into the clinical application disparities of these three medicinal snake species.
Amino Acids/chemistry*
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Animals
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Nutritive Value
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Chromatography, High Pressure Liquid
;
Snakes/classification*
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Bungarus
6.Polysaccharide extract PCP1 from Polygonatum cyrtonema ameliorates cerebral ischemia-reperfusion injury in rats by inhibiting TLR4/NLRP3 pathway.
Xin ZHAN ; Zi-Xu LI ; Zhu YANG ; Jie YU ; Wen CAO ; Zhen-Dong WU ; Jiang-Ping WU ; Qiu-Yue LYU ; Hui CHE ; Guo-Dong WANG ; Jun HAN
China Journal of Chinese Materia Medica 2025;50(9):2450-2460
This study aims to investigate the protective effects and mechanisms of polysaccharide extract PCP1 from Polygonatum cyrtonema in ameliorating cerebral ischemia-reperfusion(I/R) injury in rats through modulation of the Toll-like receptor 4(TLR4)/NOD-like receptor protein 3(NLRP3) signaling pathway. In vivo, SD rats were randomly divided into the sham group, model group, PCP1 group, nimodipine(NMDP) group, and TLR4 signaling inhibitor(TAK-242) group. A middle cerebral artery occlusion/reperfusion(MCAO/R) model was established, and neurological deficit scores and infarct size were evaluated 24 hours after reperfusion. Hematoxylin-eosin(HE) and Nissl staining were used to observe pathological changes in ischemic brain tissue. Transmission electron microscopy(TEM) assessed ultrastructural damage in cortical neurons. Enzyme-linked immunosorbent assay(ELISA) was used to measure the levels of interleukin-1β(IL-1β), interleukin-6(IL-6), interleukin-18(IL-18), tumor necrosis factor-α(TNF-α), interleukin-10(IL-10), and nitric oxide(NO) in serum. Immunofluorescence was used to analyze the expression of TLR4 and NLRP3 proteins. In vitro, a BV2 microglial cell oxygen-glucose deprivation/reperfusion(OGD/R) model was established, and cells were divided into the control, OGD/R, PCP1, TAK-242, and PCP1 + TLR4 activator lipopolysaccharide(LPS) groups. The CCK-8 assay evaluated BV2 cell viability, and ELISA determined NO release. Western blot was used to analyze the expression of TLR4, NLRP3, and downstream pathway-related proteins. The results indicated that, compared with the model group, PCP1 significantly reduced neurological deficit scores, infarct size, ischemic tissue pathology, cortical cell damage, and the levels of inflammatory factors IL-1β, IL-6, IL-18, TNF-α, and NO(P<0.01). It also elevated IL-10 levels(P<0.01) and decreased the expression of TLR4 and NLRP3 proteins(P<0.05, P<0.01). Moreover, in vitro results showed that, compared with the OGD/R group, PCP1 significantly improved BV2 cell viability(P<0.05, P<0.01), reduced cell NO levels induced by OGD/R(P<0.01), and inhibited the expression of TLR4-related inflammatory pathway proteins, including TLR4, myeloid differentiation factor 88(MyD88), tumor necrosis factor receptor-associated factor 6(TRAF6), phosphorylated nuclear factor-kappaB dimer RelA(p-p65)/nuclear factor-kappaB dimer RelA(p65), NLRP3, cleaved-caspase-1, apoptosis-associated speck-like protein(ASC), GSDMD-N, IL-1β, and IL-18(P<0.05, P<0.01). The protective effects of PCP1 were reversed by LPS stimulation. In conclusion, PCP1 ameliorates cerebral I/R injury by modulating the TLR4/NLRP3 signaling pathway, exerting anti-inflammatory and anti-pyroptotic effects.
Animals
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Toll-Like Receptor 4/genetics*
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NLR Family, Pyrin Domain-Containing 3 Protein/genetics*
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Rats, Sprague-Dawley
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Rats
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Reperfusion Injury/genetics*
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Male
;
Signal Transduction/drug effects*
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Polysaccharides/isolation & purification*
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Polygonatum/chemistry*
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Brain Ischemia/genetics*
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Drugs, Chinese Herbal/administration & dosage*
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Mice
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Humans
7.Primary intraosseous synovial sarcoma:a case report and literature review
Wen ZHAO ; Wei-Jun QIAN ; Li LI ; Yan-Min WANG ; Peng-Hui SU ; Chao-Xin ZHANG ; Liang XU ; Tie-Cheng WU ; Jun-Qi LIU ; Ya-Jun WANG
Medical Journal of Chinese People's Liberation Army 2025;50(11):1419-1425
Objective To report a case of tibial synovial sarcoma and review relevant literature to enhance understanding of this disease.Methods The clinical data of a patient with tibial synovial sarcoma treated at Kaifeng Central Hospital were retrospectively analyzed.A literature search was conducted in domestic and international databases,including China National Knowledge Infrastructure(CNKI),Wanfang Data,PubMed,Web of Science,and Embase,up to July 2024.Relevant literature was comprehensively reviewed to summarize the imaging and pathological characteristics,treatment,and prognosis of synovial sarcoma.Results A 29-year-old female patient was admitted with left lower extremity pain.X-ray examination revealed a proximal tibia space-occupying lesion suggestive of malignancy,and a mid-tibial space-occupying lesion considered benign.Contrast-enhanced computed tomography(CT)and plain magnetic resonance imaging(MRI)of the proximal tibial lesion also suggested malignancy.Ultrasound-guided biopsy of the proximal tibial tumor revealed a poorly differentiated malignant tumor.Immunohistochemistry results indicated monophasic synovial sarcoma,requiring genetic testing for definitive diagnosis.The patient underwent wide resection of the proximal left tibial malignancy with tumor-type artificial joint replacement,combined with curettage and bone cement filling for the left mid-tibial lesion under anesthesia.Postoperative pathology of space-occupying lesions in the proximal tibia confirmed monophasic synovial sarcoma,and fluorescence in situ hybridization(FISH)demonstrated a rupture of the synovial sarcoma translocation gene(SYT)(i.e.,SS18 positive).There was no recurrence or metastasis found in the patient during the reexamination 6 months after postoperative chemotherapy.As of July 2024,15 cases of genetically confirmed primary intraosseous synovial sarcoma have been reported internationally.Symptoms included pain and swelling,with a medical history of 1-2 years.The X-ray and CT findings showed osteolytic destruction with bone cortical discontinuity.In 13 cases,the intraosseous masses extended to the extraosseous area;in 2 cases,punctate calcifications were detected within the masses.Plain MRI scan showed iso-signal or hypo-signal on T1WI and hyper-signal,iso-signal,and hypo-signal on fat-suppressed T2WI,and enhanced MRI scan demonstrated heterogeneous enhancement.Pathological examination showed spindle-shaped cells under microscopy.Immunohistochemistry results showed positive epithelial membrane antigen(EMA),broad-spectrum cytokeratin(AE1/AE3),Ewing's sarcoma marker(CD99),and transducin-like enhancer of Split 1(TLE1).Twelve patients underwent surgical treatment;6 patients received adjuvant chemotherapy after surgery,of whom 4 developed local recurrence or distant metastasis at initial diagnosis,and 3 died during follow-up.Among the 6 patients who did not receive adjuvant chemotherapy,3 suffered from recurrence or distant metastasis.Conclusions Primary intraosseous synovial sarcoma is a rare malignant tumor with non-specific clinical manifestations.Imaging features typically include osteolytic destruction and intraosseous masses extending extraosseously,suggesting an intraosseous origin.Pathology and immunohistochemistry aid diagnosis,but definitive confirmation relies on further genetic testing.At present,the main treatment regimens for synovial sarcoma involve comprehensive therapies such as surgery and adjuvant chemotherapy,and the prognosis of patients is poor.
8.CURRENT DISTRIBUTION OF AEDES AEGYPTI IN LEIZHOU PENINSULA,ZHANJIANG CITY,GUANGDONG PROVINCE
Rui-Peng LU ; Jin-Hua DUAN ; Yu-Wen ZHONG ; Hui DENG ; Jun WU ; Li-Ping LIU ; Wei-Xiong YIN ; Feng XING ; Hui HUANG ; Chang-Jie FU ; Zong-Jing CHEN ; Ming-Ji CHENG ; Sheng-Jun HU ; Ya-Ting CHEN ; Wen-Ting GUO ; Li-Feng LIN
Acta Parasitologica et Medica Entomologica Sinica 2025;32(1):16-21
Objective To investigate the status of population dynamics and distribution changes of Aedes aegypti in Guangdong Province.Methods Continuous monitoring was conducted from May 2018 to July 2024 in Wushi Town and Qishui Town,Leizhou City,Zhanjiang City,Guangdong Province.Additionally,a survey of the distribution of Ae.aegypti along the Leizhou Peninsula coast was carried out.Results The density of Ae.aegypti in Zhanjiang showed a gradual decline from 2018 to 2024.The last detection of adult Ae.aegypti in Wushi Town was in September 2021,and the last larva was found in October 2023.No Ae.aegypti was detected in Qishui Town during surveys from 2021 to 2024.A survey of 18 coastal villages in the Leizhou Peninsula revealed no detections of Ae.aegypti.Conclusions This study provides a basis for understanding the distribution and population density fluctuations of Ae.aegypti,assessing its invasion risk,and scientifically conducting relevant prevention and control efforts.
9.Epidemiological and clinical characteristics of surveillance cases in a sentinel hospital for pertussis in Jiangxi Province in 2019
Hui WU ; Jie LIU ; Yuqin ZHAO ; Shicheng GUO ; Hairong WEN ; Jian LI
Shanghai Journal of Preventive Medicine 2025;37(6):507-510
ObjectiveTo analyze the epidemiological and clinical characteristics of surveillance cases in a sentinel hospital for pertussis in Jiangxi Province in 2019, and to provide corresponding references for the prevention and control of pertussis. MethodsCase investigation of pertussis was conducted among sentinel hospital surveillance cases, collecting their basic information, epidemiological characteristics, clinical characteristics, and other information. ResultsA total of 125 pertussis surveillance cases were investigated in 2019, including 73 clinically diagnosed cases (58.40%) and 52 confirmed cases (41.60%). The age of onset was mainly concentrated in children under 5 years old (108 cases, 86.40%), with the largest number of cases in infants aged less than 1-year-old (48 cases, 38.40%). Most cases had a history of receiving pertussis vaccine before onset (110 cases, 88.00%), and the intervals between the onset date and the date of last dose of pertussis vaccine in the 1‒2 doses group were significantly shorter than that in the 3‒4 doses group (U=-5.990, P<0.001). Probable household transmission of pertussis was found in 3 cases. All cases had cough symptoms, mainly manifested as whooping cough (77 cases, 61.60%), in addition to other main clinical manifestations, such as fever (76 cases, 60.80%), vomiting (30 cases, 24.00%), conjunctival congestion (27 cases, 21.60%), and inspiratory whoop (16 cases, 12.80%). A total of 73 cases (58.40%) experienced complications, including 1 death case. All the cases had multiple medical visit experiences before this visit, with an interval of 2 (0,3) days between the onset date and the first visit date. The misdiagnosis rate at the first medical visit was 88.00% (110/125), and the misdiagnosis rate of the first visit in secondary and primary hospitals was significantly higher than that in tertiary hospitals, exhibiting a statistically significant difference (χ2=21.582, P<0.001). ConclusionThe clinical symptoms of pertussis cases are often atypical, and the first diagnosis is prone to misdiagnosis, so it’s necessary to further strengthen the early diagnosis capabilities for pertussis cases in healthcare institutions, especially in the primary healthcare institutions.
10.Eccentric treadmill exercise promotes adaptive hypertrophy of gastrocnemius in rats.
Zhi-Qiang DAI ; Yu KE ; Yan ZHAO ; Ying YANG ; Hui-Wen WU ; Hua-Yu SHANG ; Zhi XIA
Acta Physiologica Sinica 2025;77(3):449-464
The present study aimed to investigate the effects of eccentric treadmill exercise on adaptive hypertrophy of skeletal muscle in rats. Thirty-two 3-month-old Sprague Dawley (SD) rats were selected and randomly assigned to one of the four groups based on their body weights: 2-week quiet control group (2C), 2-week downhill running exercise group (2E), 4-week quiet control group (4C), and 4-week downhill running exercise group (4E). The downhill running protocol for rats in the exercise groups involved slope of -16°, running speed of 16 m/min, training duration of 90 min, and 5 training sessions per week. Twenty-four hours after the final session of training, all the four groups of rats underwent an exhaustion treadmill exercise. After resting for 48 h, all the rats were euthanized and their gastrocnemius muscles were harvested for analysis. HE staining was used to measure the cross-sectional area (CSA) and diameter of muscle fibers. Transmission electron microscope was used to observe the ultrastructural changes in muscle fibers. Purithromycin surface labeling translation method was used to measure protein synthesis rate. Immunofluorescence double labeling was used to detect the colocalization levels of lysosomal-associated membrane protein 2 (Lamp2)-leucyl-tRNA synthetase (LARS) and Lamp2-mammalian target of rapamycin (mTOR). Western blot was used to measure the protein expression levels of myosin heavy chain (MHC) IIb and LARS, as well as the phosphorylation levels of mTOR, p70 ribosomal protein S6 kinase (p70S6K), and eukaryotic translation initiation factor 4E binding protein 1 (4E-BP1). The results showed that, compared with the 2C group rats, the 2E group rats showed significant increases in wet weight of gastrocnemius muscle, wet weight/body weight ratio, running distance, running time, pre- and post-exercise blood lactate levels, myofibrillar protein content, colocalization levels of Lamp2-LARS and Lamp2-mTOR, and LARS protein expression. Besides these above changes, compared with the 4C group, the 4E group further exhibited significantly increased fiber CSA, fiber diameter, protein synthesis rate, and phosphorylation levels of mTOR, p70S6K, and 4E-BP1. Compared with the quiet control groups, the exercise groups exhibited ultrastructural damage of rat gastrocnemius muscle, which was more pronounced in the 4E group. These findings suggest that eccentric treadmill exercise may promote mTOR translocation to lysosomal membrane, activating mTOR signaling via up-regulating LARS expression. This, in turn, increases protein synthesis rate through the mTOR-p70S6K-4E-BP1 signaling pathway, promoting protein deposition and inducing adaptive skeletal muscle hypertrophy. Although the ultrastructural changes of skeletal muscle are more pronounced, the relatively long training cycles during short-term exercise periods have a more significant effect on promoting gastrocnemius muscle protein synthesis and adaptive hypertrophy.
Animals
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Rats, Sprague-Dawley
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Physical Conditioning, Animal/physiology*
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Rats
;
Muscle, Skeletal/metabolism*
;
TOR Serine-Threonine Kinases/metabolism*
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Male
;
Hypertrophy
;
Adaptation, Physiological/physiology*
;
Adaptor Proteins, Signal Transducing/metabolism*
;
Ribosomal Protein S6 Kinases, 70-kDa/metabolism*
;
Intracellular Signaling Peptides and Proteins


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