ObjectiveThe rapid advancement of bioanalytical technologies has heightened the demand for high-throughput, label-free, and real-time cellular analysis. Electrochemical impedance spectroscopy (EIS) operating in the GHz frequency range (GHz-EIS) has emerged as a promising tool for characterizing cell suspensions due to its ability to rapidly and non-invasively capture the dielectric properties of cells and their microenvironment. Although GHz-EIS enables rapid and label-free detection of cell suspensions, significant challenges remain in interpreting GHz impedance data for complex samples, limiting the broader application of this technique in cellular research. To address these challenges, this study presents a novel method that integrates GHz-EIS with deep learning algorithms, aiming to improve the precision of cell suspension concentration identification and quantification. This method provides a more efficient and accurate solution for the analysis of GHz impedance data. MethodsThe proposed method comprises two key components: dielectric property dataset construction and backpropagation (BP) neural network modeling. Yeast cell suspensions at varying concentrations were prepared and separately introduced into a coaxial sensor for impedance measurement. The dielectric properties of these suspensions were extracted using a GHz-EIS dielectric property extraction method applied to the measured impedance data. A dielectric properties dataset incorporating concentration labels was subsequently established and divided into training and testing subsets. A BP neural network model employing specific activation functions (ReLU and Leaky ReLU) was then designed. The model was trained and tested using the constructed dataset, and optimal model parameters were obtained through this process. This BP neural network enables automated extraction and analytical processing of dielectric properties, facilitating precise recognition of cell suspension concentrations through data-driven training. ResultsThrough comparative analysis with conventional centrifugal methods, the recognized concentration values of cell suspensions showed high consistency, with relative errors consistently below 5%. Notably, high-concentration samples exhibited even smaller deviations, further validating the precision and reliability of the proposed methodology. To benchmark the recognition performance against different algorithms, two typical approaches—support vector machines (SVM) and K-nearest neighbor (KNN)—were selected for comparison. The proposed method demonstrated superior performance in quantifying cell concentrations. Specifically, the BP neural network achieved a mean absolute percentage error (MAPE) of 2.06% and an R² value of 0.997 across the entire concentration range, demonstrating both high predictive accuracy and excellent model fit. ConclusionThis study demonstrates that the proposed method enables accurate and rapid determination of unknown sample concentrations. By combining GHz-EIS with BP neural network algorithms, efficient identification of cell concentrations is achieved, laying the foundation for the development of a convenient online cell analysis platform and showing significant application prospects. Compared to typical recognition approaches, the proposed method exhibits superior capabilities in recognizing cell suspension concentrations. Furthermore, this methodology not only accelerates research in cell biology and precision medicine but also paves the way for future EIS biosensors capable of intelligent, adaptive analysis in dynamic biological research.

Objective To investigate the characteristics of imprinted differentially methylated regions (iDMRs) in placentas and their correlation with preeclampsia (PE). Methods A total of 43 healthy pregnant women (control group) and 33 pregnant women with PE (PE group) at Shanghai Putuo Maternity and Infant Hospital and International Peace Maternal and Child Health Hospital, Shanghai Jiao Tong University School of Medicine from September 2021 to September 2023 were selected. A total of 3 362 CpG sites in 62 iDMRs were analyzed in 76 placenta and 5 maternal blood samples using BisCap targeted bisulfite resequencing (BisCap-seq) assays. The CpG sites in the CpG islands of the iDMRs were assessed for their methylation levels and methylation linkage disequilibrium (MLD). Imprinted methylation haplotype blocks (iMHBs) were constructed based on MLD. The methylation levels and variablility of CpG sites and iMHBs were compared among the healthy placenta, PE placenta and blood samples. Results The CpG sites in the CpG islands of the iDMRs exhibited intermediate methylation, with adjacent sites displaying high MLD (methylation levels: 0.35-0.65, D’ ＞ 0.8). A total of 185 iMHBs were constructed using these coupled CpG sites, 60 placenta-specific iMHBs and 38 somatic iMHBs were found to be differentially methylated in the placenta compared with maternal blood (P_adj＜0.05). Twenty-seven iMHBs were identified with differentially variable methylation patterns in the placenta. The iMHBs methylation was unchanged in the PE placentas compared to the healthy placentas. Twenty-seven differentially methylated cytosines (DMCs) were identified outside the iMHBs structure, among which the methylation levels of 19 CpG sites showed statistically significant differences between the PE group and the control group (P_adj＜0.05). The quantitative results of placental compositions of maternal plasma cell-free DNA (cfDNA) using placenta-specific haplotype (PSH) were highly correlated with those estimated by a deconvolution methodology (r＝0.973, P＜0.01). Conclusions The genomic imprinting features in the PE placentas were obvious, and PSH could be a potential marker of the placenta to quantify the placental compositions of maternal plasma cfDNA.

ObjectiveFat infiltration has been shown to be closely related to muscle mass loss and a variety of muscle diseases. This study proposes a method based on phase-angle electrical impedance tomography (ΦEIT) to visualize the electrical characteristic response caused by muscle fat infiltration, aiming to provide a new technical means for early non-invasive detection of muscle mass deterioration. MethodsThis study was divided into two parts. First, a laboratory pork model was constructed to simulate different degrees of fat infiltration by injecting1 ml or 2 ml of emulsified fat solution into different muscle compartments, and the phase angle images were reconstructed using ΦEIT. Second, a human experiment was conducted to recruit healthy subjects (n=8) from two age groups (20-25 years old and 26-30 years old). The fat content percentage η_fat of the left and right legs was measured by bioelectrical impedance analysis (BIA), and the phase angle images of the left and right calves were reconstructed using ΦEIT. The relationship between the global average phase angle Φ_M and the spatial average phase angle Φ_Mi of each muscle compartment and fat infiltration was further analyzed. ResultsIn the laboratory pork model, the grayscale value of the image increased with the increase of η_fat and Φ_M showed a downward trend. The results of human experiments showed that at the same fat content percentage, the Φ_M of the 26-30-year-old group was about 20%-35% lower than that of the 20-25-year-old group. The fat content percentage was significantly negatively correlated with Φ_M. In addition, the M₂ (soleus) compartment was most sensitive to fat infiltration, and the spatial average phase angles of the M₂ (soleus), M₃ (tibialis posterior and flexor digitorum longus), and M₄ (tibialis anterior, extensor digitorum longus, and peroneus longus) compartments all showed significant inter-group differences. ConclusionΦEIT imaging can effectively distinguish different degrees of fat infiltration, especially in deep, small or specially located muscles, showing high sensitivity, demonstrating the potential application of this method in local muscle mass monitoring and early non-invasive diagnosis.

Objective To investigate the genetic causes of auditory neuropathy with optic atrophy in a family.Methods The proband's medical history and family history were inquired in detail,and relevant clinical examina-tions were performed to confirm the diagnosis of auditory neuropathy with optic atrophy,and the genetic pedigree of the family was drawn.Peripheral blood of proband(Ⅲ-7)was collected for whole exome sequencing,and the patho-genicity of the detected mutations were interpreted.Blood samples of proband's wife(Ⅲ-8),eldest daughter(Ⅳ-7),second daughter(Ⅳ-9)and son(Ⅳ-10)were tested for mutation sites by Sanger sequencing.Combined with clinical manifestations and examination results,the family was studied.Results The genetic pattern of this family was autosomal dominant.The proband showed decreased visual acuity at the age of 19,bilateral sensorineural deaf-ness at the age of 30,and decreased speech recognition rate.Among 20 members of the family of 5 generations,10(2 deceased)showed similar symptoms of hearing and visual impairment.Proband(Ⅲ-7),eldest daughter(Ⅳ-7)and son(Ⅳ-10)underwent relevant examination.Pure tone audiometry showed bilateral sensorineural deafness.ABR showed no response bilaterally.The 40 Hz AERP showed no response in both ears.OAE showed responses in some or all of the frequencies.No stapedial reflex was detected.The eye movement of Ⅲ-7 and Ⅳ-10 were reasona-ble in all directions,and color vision was normal.Ocular papilla atrophy was observed in different degrees in fundus examination.OCT showed thinning of optic disc nerve fibers in both eyes,and visual evoked potential showed pro-longed P100 wave peak.They were diagnosed as hereditary auditory neuropathy with optic atrophy.A mutation of the OPA1 gene c.1334G＞A(p.Arg445His,NM_015560.2)at a pathogenic locus on chromosome 3 was detected by whole exon detection in Ⅲ-7.The results of generation sequencing analysis showed that the OPA1 gene c.1334G＞A(p.Arg445His,NM_015560.2)mutation of chromosome 3 was also found in Ⅳ-7 and Ⅳ-10.Meanwhile,the gen-otypes of Ⅲ-8 and Ⅳ-9 were wild homozygous,that is,no mutation occurred.Conclusion The OPA1 c.1334G＞A(p.Arg445His,NM_015560.2)mutation site might be the pathogenic mutation in this family.

The importance of evaluating the oxygen supply system of the medical aircraft was introduced.With considerations on the characteristics of the oxygen supply system of the medical aircraft during its development and application,an oxygen supply system effectiveness evaluation method was proposed based on the analytic hierarchy process and the experience of experts in the field of medical aircraft,which involved in seven evaluation indexes of total oxygen supply,pipeline airtight-ness,single-nozzle flow adjustment characteristics,single-nozzle outlet pressure adjustment characteristics,disassembly and assembly,mechanical operation and fixation ability.The effectiveness evaluation method proposed was of significance for accurately grasping the changes in the performance of the oxygen supply system.References were provided for the ground maintenance of the oxygen supply system of the medical aircraft.[Chinese Medical Equipment Journal,2024,45(1):89-92]

Objective To explore the expression level of miR-34a-5p in pancreatic cancer cell PANC-1 and its effect on epithelial mesenchymal transition(EMT),cell invasion,metastasis,and chemotherapy resistance.Methods Construct stable transfected PANC-1/miR-34a-5p cells or PANC-1/mock cells,and divide the cells into four groups:PANC-1 group,PANC-1/miR-34a-5p group,PANC-1/mock group and PANC-1/miR-34a-5p+gemcitabine group.All four groups of cells were cultured for 24 h.Real-time quantitative polymerase chain reaction was used to detect the expression of miR-34a-5p in PANC-1 cells before and after transfection;Western blotting was used to detect the expression of EMT-related proteins;wound healing experiment was used to detect cell migration ability;the Transwell method was used to detect cell invasion ability;cell counting kit-8(CCK-8)test was used to detect cell proliferation.Results The expression levels of miR-34a-5p in PANC-1 group,PANC-1/mock group,PANC-1/miR-34a-5p group and PANC-1/miR-34a-5p+gemcitabine group were 1.01±0.08,1.03±0.06,2.43±0.15 and 1.76±0.21;the levels of E-cadherin were 0.61±0.12,0.63±0.08,0.24±0.15 and 0.48±0.05;the levels of Vimentin were 0.56±0.34,0.58±0.29,1.08±0.19 and 0.82±0.11;the relative cell migration levels were(41.48±4.94),(42.97±6.45),(81.42±6.85)and(63.54±7.63)distance·μm-1;the number of invasive cells were 212.62±9.80,209.46±13.67,463.83±35.22 and 325.46±28.44;the survival rates were(13.28±5.24)％,(14.37±4.79)％,(46.15±11.83)％and(35.78±9.42)％.The above indicators in the PANC-1/miR-34a-5p group showed statistically significant differences compared to the PANC-1 and PANC-1/mock groups(all P＜0.05).Conclusion Overexpression of miR-34a-5p promotes EMT of pancreatic cancer cells,migration of pancreatic cancer cells,invasion of pancreatic cancer cells,and chemotherapy resistance of pancreatic cancer cells.

Nanozyme is novel nanoparticle with enzyme-like activity, which can be classified into peroxidase-like nanozyme, catalase-like nanozyme, superoxide dismutase-like nanozyme, oxidase-like nanozyme and hydrolase-like nanozyme according to the type of reaction they catalyze. Since researchers first discovered Fe₃O₄ nanoparticles with peroxidase-like activity in 2007, a variety of nanoparticles have been successively found to have catalytic activity and applied in bioassays, inflammation control, antioxidant damage and tumor therapy, playing a key role in disease diagnosis and treatment. We summarize the use of nanozymes with different classes of enzymatic activity in the diagnosis and treatment of diseases and describe the main factors influencing nanozyme activity. A Mn-based peroxidase-like nanozyme that induces the reduction of glutathione in tumors to produce glutathione disulfide and Mn²⁺, which induces the production of reative oxygen species (ROS) in tumor cells by breaking down H₂O₂ in physiological media through Fenton-like action, thereby inhibiting tumor cell growth. To address the limitation of tumor tissue hypoxia during photodynamic tumor therapy, the effect of photodynamic therapy is significantly enhanced by using hydrogen peroxide nanozymes to catalyze the production of oxygen from H₂O₂. In pathological states, where excess superoxide radicals are produced in the body, superoxide dismutase-like nanozymes are able to selectively regulate intracellular ROS levels, thereby protecting normal cells and slowing down the degradation of cellular function. Based on this principle, an engineered nanosponge has been designed to rapidly scavenge free radicals and deliver oxygen in time to save nerve cells before thrombolysis. Starvation therapy, in which glucose oxidase catalyzes the hydrolysis of glucose to gluconic acid and hydrogen peroxide in cancer cells with the involvement of oxygen, attenuates glycolysis and the production of intermediate metabolites such as nucleotides, lipids and amino acids, was used to synthesize an oxidase-like nanozyme that achieved effective inhibition of tumor growth. Furthermore, by fine-tuning the Lewis acidity of the metal cluster to improve the intrinsic activity of the hydrolase nanozyme and providing a shortened ligand length to increase the density of its active site, a hydrolase-like nanozyme was successfully synthesized that is capable of cleaving phosphate bonds, amide bonds, glycosidic bonds and even biofilms with high efficiency in hydrolyzing the substrate. All these effects depend on the size, morphology, composition, surface modification and environmental media of the nanozyme, which are important aspects to consider in order to improve the catalytic efficiency of the nanozyme and have important implications for the development of nanozyme. Although some progress has been made in the research of nanozymes in disease treatment and diagnosis, there are still some problems, for example, the catalytic rate of nanozymes is still difficult to reach the level of natural enzymes in vivo, and the toxic effects of some heavy metal nanozymes material itself. Therefore, the construction of nanozyme systems with multiple functions, good biocompatibility and high targeting efficiency, and their large-scale application in diagnosis and treatment is still an urgent problem to be solved. (1) To improve the selectivity and specificity of nanozymes. By using antibody coupling, the nanoparticles are able to specifically bind to antigens that are overexpressed in certain cancer cells. It also significantly improves cellular internalization through antigen-mediated endocytosis and enhances the enrichment of nanozymes in target tissues, thereby improving targeting during tumor therapy. Some exogenous stimuli such as laser and ultrasound are used as triggers to control the activation of nanozymes and achieve specific activation of nanozyme. (2) To explore more practical and safer nanozymes and their catalytic mechanisms: biocompatible, clinically proven material molecules can be used for the synthesis of nanoparticles. (3) To solve the problem of its standardization and promote the large-scale clinical application of nanozymes in biomonitoring. Thus, it can go out of the laboratory and face the market to serve human health in more fields, which is one of the future trends of nanozyme development.

Objective This study aimed to comprehensively analyze and compare the clinicopathological features and prognosis of Chinese patients with human epidermal growth factor receptor 2(HER2)-low early breast cancer(BC)and HER2-IHC0 BC. Methods Patients diagnosed with HER2-negative BC(N=999)at our institution between January 2011 and December 2015 formed our study population.Clinicopathological characteristics,association between estrogen receptor(ER)expression and HER2-low,and evolution of HER2 immunohistochemical(IHC)score were assessed.Kaplan-Meier method and log-rank test were used to compare the long-term survival outcomes(5-year follow-up)between the HER2-IHC0 and HER2-low groups. Results HER2-low BC group tended to demonstrate high expression of ER and more progesterone receptor(PgR)positivity than HER2-IHC0 BC group(P<0.001).The rate of HER2-low status increased with increasing ER expression levels(Mantel-Haenszel χ2 test,P<0.001,Pearson's R=0.159,P<0.001).Survival analysis revealed a significantly longer overall survival(OS)in HER2-low BC group than in HER2-IHC0 group(P=0.007)in the whole cohort and the hormone receptor(HR)-negative group.There were no significant differences between the two groups in terms of disease-free survival(DFS).The discordance rate of HER2 IHC scores between primary and metastatic sites was 36.84%. Conclusion HER2-low BC may not be regarded as a unique BC group in this population-based study due to similar clinicopathological features and prognostic roles.

Objective:To summarize the clinical features of 14 cases with clinically and genetically diagnosed progressive pseudorheumatoid dysplasia(PPRD) and analyze the characteristics of joint lesions caused by PPRD to provide references for clinical diagnosis and treatment of PPRD.Methods:A retrospective analysis was made on the clinical data and genetic test data of 14 patients admitted to Children′s Hospital, Capital Institute of Pediatrics and cooperative units, from December 2017 to September 2023.An observational retrospective analysis was performed on hospitalization and follow-up data, and correlation factors were analyzed using the Kendall correlation test.Results:The 14 patients, including 6 males and 8 females, were all Chinese Han children.The average age of onset was 6.12 years(2-11 years), the average age of diagnosis was 10.61 years old(5-17 years old), and the average duration of the disease was 4.46 years(0.5-6.0 years) at diagnosis.The number of joint involvements ranged from 4 to 14, with an average of 9.20.There were 12 patients with claudication as the first symptom.All these 14 children had limited hip mobility and no obvious hip pain.The hip joint imaging indicated that space narrowing occurred in 11 cases, femoral neck shortening in 2 cases, femoral head displacement in 4 cases, and articular surface sclerosis, cystic degeneration or bone destruction in 8 cases.The joints of the four limbs were mainly manifested as enlargement of the proximal interphalangeal joints and metacarpophalangeal joints of both hands.The other joints were knees(11 cases), elbows(8 cases), wrists(7 cases) and ankles(5 cases) in the order of easy involvement, and the shoulder joint was less involved(1 case).The spine was mainly characterized by changes in the curvature, and limited movement was found in 8 cases.Thoracic and lumbar spines were mainly involved(13 cases), while cervical involvement was rare(1 case).The duration of the disease at diagnosis was positively correlated with the number of joint involvements and the number of joint mobility limitations( r=0.584, 0.671; P=0.007, 0.002).In this study, 8 children were misdiagnosed as juvenile idiopathic arthritis, and the longest misdiagnosis time was 6 years.All the 14 children had CCN6 gene mutations, including 10 complex heterozygous mutations and 4 homozygous mutations.Five children had c. 342T>G and c. 667T>G, 4 children had c. 589 + 2(IVS4)T>C, 3 children had c. 866dup, and 2 children had c. 136C>T and c. 624dupA. Conclusions:PPRD is characterized by multiple joint involvements, among which hip involvement is the most common.The lesions are serious and easily misdiagnosed as juvenile idiopathic arthritis.The number of affected joints increases gradually with the prolongation of the disease course.

Lactic acid produced by muscles during exercise training is transported to the liver for metabolism through the bloodstream.In this process,the lactate acid level increases with the increase of exercise intensity,and the concentration of lactate acid in interstitial matrix of muscle tissues increases subsequently,leading to muscle fatigue.Transcutaneous electrical nerve stimulation(TENS)is a widely used medical method for muscle relaxation and improving peripheral blood circulation.To monitor the potential of TENS to alleviate muscle fatigue,this study adopted electrical impedance tomography(EIT)method to visualize the alleviating effect of TENS on muscle fatigue by detecting the tissue electrical characteristics response caused by the changes in blood lactate concentration,a biomarker of muscle fatigue.An experimental platform was thus constructed to mimic the changes of blood lactate concentration(Cbl)in the muscle tissue model,and to measure the trend of the spatial-mean conductivity((σ))in the mimic model during the Cbl change.The blood flow velocity was closely related to the metabolic rate of the lactate in the blood.TENS could speed up blood flow and effectively reduced the lactate accumulation in muscle tissue.However,too fast blood flow velocity was prone to cause secondary ventricular fibrillation disease,which threatened the safety of human life.To avoid this threat,a real-time blood flow velocity mimic platform was developed in this study to monitor the(σ)changes caused by the changes in blood flow velocity(vph)in the vicinity of mimic blood vessels.The correlations between Cbl vs(σ),and vph vs(σ)in the mimic muscle tissue were verified by Pearson test.Pearson correlation analysis results showed a positive correlation between Cbl and(σ)(r=0.9113,p<0.05),and betweenvph and(σ)(r=0.9782,p<0.001).The approach presented here quantitatively assessed the potential of TENS stimulation-induced changes in lactate concentration and blood flow velocity for alleviating muscle fatigue through(σ).