ObjectiveThe malaria parasites remodel the host erythrocyte structure by exporting parasite proteins that interact with the membrane skeleton proteins of red blood cells (RBCs), facilitating their intracellular survival and pathogenicity. Skeleton-binding protein 1 (SBP1) is a conserved exported protein across Plasmodium species. In Plasmodium falciparum, SBP1 has been reported to interact with erythrocyte membrane skeleton proteins 4.1R and spectrin, while its contribution to erythrocyte remodeling and parasite virulence in Plasmodium berghei (Pb) remains unclear. This study aims to determine whether PbSBP1 associates with the host cytoskeletal protein 4.1R and to investigate its role in the remodeling of host RBCs and the pathogenicity of Plasmodium berghei. MethodsIn Plasmodium berghei, the relationship between PbSBP1 and the erythrocyte cytoskeletal protein 4.1R was examined using co-immunoprecipitation. A Pbsbp1 gene knockout mutant of Plasmodium berghei (Pbsbp1∆) was generated based on the principle of double crossover homologous recombination. The deformability of erythrocytes infected with Pbsbp1∆ parasites was assessed using microfluidic methods. Microchannels with an array of cylindrical pillars were used to detect modifications in infected RBC deformability. The infected RBCs were squashed between the rows and recovered between the columns and the transit velocity (μm/s) of infected RBCs travelling through the microchannel was recorded. The component of the erythrocyte membrane skeleton junctional complex, tropomodulin (TMOD), was fluorescently labeled, and the cytoskeletal network of infected erythrocytes was imaged using super-resolution stochastic optical reconstruction microscopy (STORM) to analyze ultrastructural changes in the cytoskeleton of wild-type (WT) and Pbsbp1∆-infected erythrocytes. Actin-based junctional complexes were displayed as individual clusters by the labeled TMOD in the STORM images, and the cluster densities and distances between adjacent clusters of infected RBCs were calculated. Additionally, rodent malaria models (BALB/c mice) and experimental cerebral malaria models (C57BL/6 mice) were employed to monitor the growth of Pbsbp1∆ and WT parasites during the intraerythrocytic stage and their capacity to induce cerebral malaria in mice. ResultsPbSBP1 may participate in the remodeling of infected erythrocytes through direct or indirect interaction with the erythrocyte cytoskeletal protein 4.1R. Microfluidic assays revealed that the deformability of erythrocytes infected with Pbsbp1∆ parasites was significantly enhanced compared to those infected with WT parasites. STORM imaging further demonstrated that the ultrastructure of the erythrocyte cytoskeleton in Pbsbp1∆-infected cells was altered relative to that in WT-infected erythrocytes. The distances between nearest neighbors of clusters had a tendency to increase while the cluster densities were decreased in Pbsbp1∆-infected RBCs compared to WT-infected RBCs. Subsequent phenotypic analysis indicated that the growth rate of Pbsbp1∆ parasites during the intraerythrocytic stage was significantly slower than that of WT parasites, and their ability to induce cerebral malaria in mice was also attenuated. These findings suggest that PbSBP1 is involved in the remodeling of the erythrocyte membrane skeleton, likely through its direct or indirect interaction with protein 4.1R, thereby regulating the deformability of infected erythrocytes and influencing the pathogenicity of the blood-stage parasites. ConclusionThis study establishes a role for PbSBP1 in host erythrocyte remodeling and parasite virulence, providing new research strategies for the prevention and treatment of malaria.

Objective To analyze the association between lifestyle and the risk of type 2 diabetes(T2D)among adult residents.Methods The data was sourced from the Shanghai Suburban Adult Cohort and Biobank.A total of 42 096 adult residents who had not developed T2D were recruited from four districts of Shanghai(Songjiang,Jiading,Minhang,and Xuhui)between 2016 and 2019.The follow-up ended on Feb 28,2023.A structured questionnaire was used to collect information on six lifestyle-related items,including smoking,alcohol consumption,BMI,waist circumference(WC),physical activity,and diet.The unhealthy lifestyle scores(UHLS)were calculated by counting the number of all the unhealthy lifestyle items,with a range of 0-6.New-onset T2D events diagnosed by physicians were obtained through the medical information system.Cox proportional hazards regression model and restricted cubic spline model were utilized to evaluate the association between unhealthy lifestyles and the risk of T2D incidence.Results About 28.1%of the participants led 4-6 unhealthy lifestyles.A total of 1 752 new T2D cases were identified during 218 513.4 person-years of follow-up.Analysis of single unhealthy lifestyle showed that abnormal WC(HR=1.5,95%CI:1.4-1.7)and abnormal BMI(HR=1.3,95%CI:1.2-1.5)were associated with an increased risk of T2D.Compared with individuals with a UHLS of 0-1,those with a UHLS of 3 and 4-6 had 30%(95%CI:1.1-1.6)and 50%(95%CI:1.2-1.8)higher risks of T2D,respectively.Each additional unhealthy lifestyle was associated with a 10%increase in T2D incidence risk(HR=1.1,95%CI:1.1-1.2).Conclusion The risk of T2D in adult residents increases with the cumulative number of unhealthy lifestyles.Adult residents with abnormal WC or BMI,or have three or more unhealthy lifestyles accumulated,will increase the risk of new-onset T2D.

Objective:To investigate the clinicopathological features and differential diagnosis of male genital system lympho-ma(MGSL).Methods:We retrospectively analyzed the clinicopathological and immunophenotypic features and prognosis of 80 ca-ses of MGSL.Results:The onset age of the MGSL patients ranged from 4 to 85(median 62)years old.All the cases showed non-specificity of the imaging features and clinical manifestations.MGSL was located mainly in the testis(n=66),followed by the pros-tate(n=7),epididymis(n=3),scrotum(n=3)and penile glans(n=1).Diffused large B cell lymphoma(DLBCL)was the most common pathological type(n=62),next came extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue(MALT)(n=7)and other rare types(n=12).During the 1-112-month follow-up of 10 of the 19 patients,1 died at 1 month af-ter diagnosed with prostatic B-lymphoblastic lymphoma(B-LBL)and another 1 died at 50 months after diagnosed with testicular DLBCL.Conclusion:MGSL is rare clinically,mainly of the DLBCL type pathologically,lacking specificity in clinical symptoms and imaging manifestation.The definite diagnosis of the malignancy depends on histopathology combined with related molecular exami-nation and immunohistochemical labeling,and R-CHOP chemotherapy is the first choice for its treatment.

Objective To compare the effects of different detector combinations of 320-row CT on the image quality and radiation dose of head CT to explore the feasibility of using a wide detector for head CT scanning.Methods Totally 100 patients underwent head CT scanning due to trauma or cerebrovascular disease at some hospital from June to August 2023 were collected prospectively and divided into group A and group B by using block randomization grouping method,with the length of the block group being 2 and 50 patients in each group.In group A,all the detectors had the widths at z-axis direction being 40×0.5 mm and head scanning was completed after multiple exposures;in group B,detector combinations with widths of 280×0.5 mm or 320×0.5 mm were chosen based on the patient's head size in the head-foot direction(z-axis direction),and head scanning was performed with a single-turn exposure.The remaining scanning and image reconstruction parameters in the two groups were kept completely consistent.The head image quality of the 2 groups was evaluated objectively and scored subjectively by 2 radiologists.The volume CT dose index(CTDIvol),dose length product(DLP)and exposure time of the 2 groups were recorded,and the effective dose(ED)was calculated.SPSS 22.0 software was used for statistical analysis.Results In terms of objective evaluation of image quality,at the level of the parietal skull group B had the CT value of gray matter,image noise and contrast to noise ratio(CNR)of the images higher than those of group A,and the differences were statistically significant(all P<0.05);at the level of the posterior skull group B had the CT values of gray and white matter,image noise and air noise lower while CNR higher than those of group A,and the differences were statistically significant(all P<0.05).In terms of subjective scoring of image quality,at the levels of parietal and posterior skull group A behaved better than group B,and the differences were statistically significant(all P<0.05).In group A 5 patients had obvious motion artifacts affecting the diagnosis and the image quality scores not higher than 2,and secondary scanning had to be carried out;In group B all the patients had no obvious motion artifacts and met the diagnosis requirements.When compared with group A Group B had the CTDIvol,DLP,ED and exposure time decreased by 17.44%,17.24%,17.48%and 85.53%,respectively,and the differences were statistically significant(all P<0.05).Conclusion A wide detector gains advantages over a 20 mm detector in image quality when 320-row CT is used for head CT scanning,with the diagnosis requirements satisfied.[Chinese Medical Equipment Journal,2025,46(4):57-62]

An assay was established for detection of toxigenic Clostridioides difficile by combining microfluidic chip analysis with immunochromatography,and its performance was evaluated and compared with those of the Xpert C.difficile/Epi and VIDAS CD AB tests.Primer pairs were designed according to the tcdB and tpi genes in C.difficile.The specificity,limit of detection,reproducibility,and stability were evaluated.A total of 215 stool samples from patients with diarrhea were collected and tested in parallel with the Xpert C.difficile/Epi,VIDAS CDAB,and our assay.C.difficile was isolated from samples,and the tcdB gene was identified when discrepant results were obtained from the three above assays.Our assay showed no cross-reaction with other diarrhea-associated pathogens.Its reproducibility was 100％in testing of two standard plasmids containing tcdB and tpi genes at two concentrations(105 and 102 copies/μL).Two standard plasmids were detected after the PCR and immunochromatography reagents had been stored for 3,6,9,and 12 months,and all the results were posi-tive.The limit of detection was 10 copies/μL for toxigenic C.difficile.Testing of 33 samples positive for C.difficile with our assay(33/215,15.3％)yielded findings statistically coherent with those of the Xpert C.difficile/Epi test(kappa value=0.965).The sensitivity,specificity,positive predictive value,and negative predictive value of our assay,with respect to Xpert C.difficile/Epi as the standard,were 94.3％,100.0％,100.0％,and 98.9％;these values were significantly higher than those of VIDAS CDAB(60.0％,98.9％,91.3％,and 92.7％)(Kappa=0.714,OR=157.50,95％CI:62.03-847.28,P=0.013).In conclusion,our newly developed assay is specific,stable,and reproducible,and may be used for rapid and accu-rate detection of toxigenic C.difficile.The assay could be used for C.difficile infection screening in outpatient and emergen-cy,community medical service center,and epidemiological settings.

BACKGROUND:Iron overload is an independent factor inducing osteoporosis,but the action mechanism is currently unclear.Therefore,exploring the effects of iron overload on osteoblast-related cells will help to deeply understand the pathogenesis of osteoporosis and provide potential strategies for osteoporosis treatment.OBJECTIVE:To explore the effects of iron overload environment on osteoblast precursor cell activity,ferroptosis,and osteogenic differentiation.METHODS:Osteoblast precursor cells(MC3T3-E1 cells)were divided into blank group,iron overload group,fer-1 group,and deferoxamine group.The iron overload group was treated with 300 μmol/L ammonium ferric citrate in the culture medium for 48 hours to simulate the iron overload microenvironment.The cells in fer-1 group and deferoxamine group were pretreated with 5 μmol/L antioxidant fer-1 and 5 μmol/L deferoxamine for 8 hours,respectively,and then added with 300 μmol/L ammonium ferric citrate for 48 hours.CCK-8 assay was used to determine the cell viability.Intracellular reactive oxygen species levels were detected employing a reactive oxygen species fluorescent probe.Changes in mitochondrial membrane potential were monitored with a mitochondrial membrane potential fluorescent probe.Mitochondrial morphology was observed employing transmission electron microscopy.Cellular glutathione levels were measured with a reduced glutathione colorimetric assay kit.Lipid peroxidation levels were assessed with a malondialdehyde colorimetric assay kit.Cellular ferrous ion levels were determined with a ferrous ion colorimetric assay kit.The osteogenic and mineralization capabilities of the cells were verified by alkaline phosphatase staining and alizarin red staining.Collagen secretion ability was detected using Sirius Red staining.The expression of osteogenic/ferroptosis-related genes and proteins was examined through reverse transcription quantitative polymerase chain reaction and western blot analysis.RESULTS AND CONCLUSION:(1)In an iron-overload environment,the mitochondrial membrane potential of cells decreased and their structure was compromised,with an elevation in intracellular lipid peroxidation levels and a downregulation of genes and proteins associated with ferroptosis resistance.However,pretreatment with fer-1 and deferoxamine led to an increase in mitochondrial membrane potential and partial restoration of morphology,a reduction in intracellular lipid peroxidation levels,and an upregulation of genes and proteins related to ferroptosis resistance.(2)In an iron-overload environment,the levels of cellular alkaline phosphatase,the formation of mineralized nodules,and the synthesis of collagen fibers were all found to be decreased.Pretreatment with fer-1 and deferoxamine was observed to upregulate the expression of osteogenic differentiation in cells.(3)In summary,iron overload could increase intracellular oxidative stress levels,mediate ferroptosis in MC3T3-E1 cells and inhibit osteogenic differentiation,thereby inducing osteoporosis.Therefore,maintaining iron homeostasis and inhibiting osteogenesis-related ferroptosis may be potential strategies to prevent or treat osteoporosis.

The application of sensors to the monitoring of spinal morphology and motion was reviewed in terms of the research object and monitoring index.The present situation of the application of sensors was introduced,such as inertial sensor,stretchable strain sensor and electromagnetic sensor.The deficiencies of sensors applied to the monitoring of spinal morphology and motion were analyzed,and the future directions of the application were pointed out.[Chinese Medical Equipment Journal,2025,46(6):105-110]

This study was aimed at developing an in vitro fluorescent substrate assay for the activity of leucyl aminopeptid-ase(LAP)from Echinococcus multilocularis and comparing it with the chemical chromogenic substrate enzyme activity assay.Through the establishment of reaction conditions for the fluorescent substrate-based in vitro enzyme activity assay,we com-pared the differences between the fluorescent substrate L-Leucine-7-amido-4-methylocoumarin(Leu-AMC)and the chemical chromogenic substrate L-Leucine-4-nitroanilide(Leu-pNA)through molecular docking,inhibition rates,and precision measures.Molecular docking revealed that the fluorescent substrate Leu-AMC had higher affinity for the protein than the chemical chromogenic substrate Leu-pNA.Through analysis of the effects of varying reaction conditions on fluorescence intensi-ty,we optimized the fluorescent substrate enzyme activity assay to demonstrate favorable performance at a reaction temperature of 37℃,a pH of 9.0,a protein concentration of 800 nmol/L,and a reaction duration of 60 minutes.Leu-AMC exhibited significant and distinct responses at a 5 μmol/L substrate concentration,under varying substrate conditions.The fluo-rescent substrate assay demonstrated more significant intergroup differences than the chemical chromogenic substrate assay when various inhibitors were added.This study established a fluorescence-based enzyme activity assay for leucyl aminopeptidase from Echinococcus multilocularis by using Leu-AMC as the substrate;this method demonstrated a more significant intergroup difference and sensitivity than the chemical chromogenic substrate assay.

Isoflavones which mainly distributed in leguminous plants have plenty of health benefits.Isoflavone synthase(IFS)is a membrane-associated cytochrome P450 enzyme(CYP450)which carries out the unique aryl-ring migration and hydroxylation.So far,few crystal structures of plant P450s have been obtained.We determined the crystal structure of IFS from Medicago truncatula at 1.9 ? by MAD method using a selenomethionine substituted crystal and conducted molecular docking and mutagenesis study.The structure of IFS complexed with imidazole exhibits the helix Ⅰa-loop-helix Ⅰβ motif which cor-responds to helix Ⅰ of other P450s.Compared with structures of common P450s,IFS/imidazole structure contains an extra domain,i.e.,the γ-domain.The structure reveals a homodimer in which the γ-domain of one molecule interacts with the β-domain of another.The plane of heme group makes an angle of ap-proximately 40° with the helix Ⅰa-loop-helix Ⅰβ motif.Molecular docking combined with mutagenesis study suggested that Trp-128 and Asp-300 might play important roles in substrate binding and recogni-tion.Phe-301,Ser-303 and Gly-305 from the helix Ⅰa-loop-helix Ⅰβ motif may play important roles in the aryl-ring migration.These novel structural features reveal insights into the unique reaction mechanism of IFS and provide a basis for engineering IFS in leguminous crops for health purpose.

Objective To design a phased array ultrasonic focusing control system based on sinusoidal signal excitation in order to avoid the introduction of high-frequency interference components into the ultrasonic transducer and improve the electronic focusing performance of phased array ultrasound.Methods The system designed mainly used the high-speed field programmable gate array(FPGA)chip combined with the high-speed digital to analog converter(DAC)to realize synchronous output and control of multi-channel sinusoidal signals.There were 8 sinusoidal excitation emission modules based on FPGA and DAC and one sinusoidal ultrasonic excitation control module based on ZYNQ MPSoC involved in the hardware part of the system,in which the emission modules generated multi-channel sinusoidal excitations and timing control of sinusoidal signals within the module and the control module was responsible for controlling the triggering timing between each sinusoidal excitation transmitter module.The system developed had its software designed with MATLAB App Designer to improve the human-computer interaction experience.Performance verification was carried out for the system by testing the output waveform,inter-channel delay error and focused sound field of each channel.Results The system developed achieved generation and timing control of 64-channel sinusoidal ultrasound excitations,with the output channel main frequency being 0.5 MHz,amplitude within 0 and±12.5 V and the inter-channel delay errors not higher than 26.0 ns;a focused sound field with a focal spot diameter of 4.2 mm(-3 dB)at a depth of 50 mm was obtained when the system was applied to driving a 64-array phased-array transducer.Conclusion The system designed is capable of realizing ultrasonic electron focusing under sinusoidal excitation,which helps to improve the focusing resolution of non-invasive and precise deep brain stimulation techniques relying on the accuracy of ultrasonic focusing such as transcranial magneto-acoustic stimulation(TMAS)and transcranial ultrasonic stimulation(TUS).[Chinese Medical Equipment Journal,2025,46(5):14-20]