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Biomedical subjects

Hu Chen

Publications and source records attributed to Hu Chen.

At least 19 recordsLinked to original sources
PubMed2026

Application of Three-Dimensionally Printed Surgical Guides in Precise Sacral Tumor Excision and Defect Reconstruction.

OBJECTIVE: Precise resection of sacral tumors remains technically demanding due to their deep anatomical location and close proximity to critical neurovascular structures. Conventional freehand techniques often result in suboptimal resection margins, excessive blood loss, and compromised lumbopelvic stability. This study evaluated whether patient-specific three-dimensional (3D)-printed guiding templates improve surgical accuracy and perioperative outcomes in sacral tumor resection and reconstruction. METHODS: Nineteen patients undergoing en bloc sacral tumor resection (S1-S3 involvement) with spinopelvic reconstruction (2006-2020) were retrospectively analyzed. Patients were divided into a 3D-printing group (n&#x2009;=&#x2009;10) and a conventional freehand group (n&#x2009;=&#x2009;9). In the 3D-printing group, computer-aided design and 3D-printed templates were used for osteotomy, screw placement, and defect reconstruction. Perioperative metrics, surgical accuracy, and complications were compared between groups using Welch's t-test and the Hodges-Lehmann method; oncologic events during follow-up were recorded descriptively. RESULTS: The 3D-printing group demonstrated significantly shorter operative time (456.5&#x2009;&#xb1;&#x2009;62.36 vs. 574.44&#x2009;&#xb1;&#x2009;114.58&#x2009;min, p&#x2009;=&#x2009;0.012), reduced blood loss (4081.40&#x2009;&#xb1;&#x2009;838.99 vs. 5090.0&#x2009;&#xb1;&#x2009;1059.67&#x2009;mL, p&#x2009;=&#x2009;0.034), and fewer fluoroscopic exposures (4.2&#x2009;&#xb1;&#x2009;0.79 vs. 10.0&#x2009;&#xb1;&#x2009;1.58, p&#x2009;<&#x2009;0.001) compared with the conventional group. Osteotomy accuracy was also superior in the 3D-printing group, with significantly lower angular deviation (3.33&#xb0;&#x2009;&#xb1;&#x2009;0.45&#xb0; vs. 6.79&#xb0;&#x2009;&#xb1;&#x2009;2.16&#xb0;, p&#x2009;=&#x2009;0.0012). Postoperative complication rates were comparable (30% vs. 44.4%, p&#x2009;=&#x2009;0.649), but hospital stay was significantly shorter in the 3D-printing group (10.7&#x2009;&#xb1;&#x2009;2.71 vs. 18.11&#x2009;&#xb1;&#x2009;4.01&#x2009;days, p&#x2009;<&#x2009;0.001). CONCLUSION: Patient-specific 3D-printed guiding templates enhance precision in sacral tumor excision and reconstruction, improving surgical efficiency and perioperative safety. This computer-assisted, template-guided approach represents a valuable advancement for complex sacral oncologic surgery.

Humans↗
PubMed2026

Single-nucleus profiling reveals a core disease signature and cell type-specific vulnerabilities in early Rett syndrome.

Rett syndrome (RTT) is an X-linked neurological disorder caused by MECP2 mutations, creating distinct cellular environments in females (mosaic) versus males (nonmosaic). Despite female patients representing most cases, how mosaicism contributes molecularly to RTT pathogenesis, particularly in presymptomatic stages, remains poorly understood. To address this question, we profiled hippocampal transcriptomes of young female and male RTT mice using bulk and single-nucleus RNA sequencing. We identified a core disease signature of consistently dysregulated genes only in MeCP2- cells across RTT models. Moreover, we uncovered non-cell autonomous effects exclusively in female MeCP2+ excitatory neurons, suggesting that these circuits are more vulnerable early in the mosaic RTT environment. The single-nuclei data also revealed an underappreciated MeCP2- interneuron subtype that had the most transcriptional dysregulation in both male and female RTT hippocampi. Together, these data highlight the different effects of MeCP2 loss on excitatory and inhibitory circuits between the mosaic and nonmosaic environments in early RTT pathogenesis.

Rett Syndrome↗
PubMed2025

TET2-mutant myeloid cells mitigate Alzheimer's disease progression via CNS infiltration and enhanced phagocytosis in mice.

Clonal hematopoiesis (CH) is associated with many age-related diseases, but its interaction with Alzheimer's disease (AD) remains unclear. Here, we show that TET2-mutant CH is associated with a 47% reduced risk of late-onset AD (LOAD) in the UK Biobank, whereas other drivers of CH do not confer protection. In a mouse model of AD, transplantation of Tet2-mutant bone marrow reduced cognitive decline and &#x3b2;-amyloid plaque formation, effects not observed with Dnmt3a-mutant marrow. Bone-marrow-derived microglia-like cells were detected at an increased rate in Tet2-mutant marrow recipients, and TET2-mutant human induced pluripotent stem cell (iPSC)-derived microglia were more phagocytic and hyperinflammatory than DNMT3A-mutant or wild-type microglia. Strikingly, single-cell RNA sequencing (scRNA-seq) revealed that macrophages and patrolling monocytes were increased in brains of mice transplanted with Tet2-mutant marrow in response to chemokine signaling. These studies reveal a TET2-specific protective effect of CH on AD pathogenesis mediated by peripheral myeloid cell infiltration.

Animals↗
PubMed2024

Acute MeCP2 loss in adult mice reveals transcriptional and chromatin changes that precede neurological dysfunction and inform pathogenesis.

Mutations in the X-linked methyl-CpG-binding protein 2 (MECP2) gene cause Rett syndrome, a severe childhood neurological disorder. MeCP2 is a well-established transcriptional repressor, yet upon its loss, hundreds of genes are dysregulated in both directions. To understand what drives such dysregulation, we deleted Mecp2 in adult mice, circumventing developmental contributions and secondary pathogenesis. We performed time series transcriptional, chromatin, and phenotypic analyses of the hippocampus to determine the immediate consequences of MeCP2 loss and the cascade of pathogenesis. We find that loss of MeCP2 causes immediate and bidirectional progressive dysregulation of the transcriptome. To understand what drives gene downregulation, we profiled genome-wide histone modifications and found that a decrease in histone H3 acetylation (ac) at downregulated genes is among the earliest molecular changes occurring well before any measurable deficiencies in electrophysiology and neurological function. These data reveal a molecular cascade that drives disease independent of any developmental contributions or secondary pathogenesis.

Animals↗
PubMed2006

NBA-Palm: prediction of palmitoylation site implemented in Naïve Bayes algorithm.

BACKGROUND: Protein palmitoylation, an essential and reversible post-translational modification (PTM), has been implicated in cellular dynamics and plasticity. Although numerous experimental studies have been performed to explore the molecular mechanisms underlying palmitoylation processes, the intrinsic feature of substrate specificity has remained elusive. Thus, computational approaches for palmitoylation prediction are much desirable for further experimental design. RESULTS: In this work, we present NBA-Palm, a novel computational method based on Naïve Bayes algorithm for prediction of palmitoylation site. The training data is curated from scientific literature (PubMed) and includes 245 palmitoylated sites from 105 distinct proteins after redundancy elimination. The proper window length for a potential palmitoylated peptide is optimized as six. To evaluate the prediction performance of NBA-Palm, 3-fold cross-validation, 8-fold cross-validation and Jack-Knife validation have been carried out. Prediction accuracies reach 85.79% for 3-fold cross-validation, 86.72% for 8-fold cross-validation and 86.74% for Jack-Knife validation. Two more algorithms, RBF network and support vector machine (SVM), also have been employed and compared with NBA-Palm. CONCLUSION: Taken together, our analyses demonstrate that NBA-Palm is a useful computational program that provides insights for further experimentation. The accuracy of NBA-Palm is comparable with our previously described tool CSS-Palm. The NBA-Palm is freely accessible from: http://www.bioinfo.tsinghua.edu.cn/NBA-Palm.

Acyltransferases↗
PubMed2006

MeMo: a web tool for prediction of protein methylation modifications.

Protein methylation is an important and reversible post-translational modification of proteins (PTMs), which governs cellular dynamics and plasticity. Experimental identification of the methylation site is labor-intensive and often limited by the availability of reagents, such as methyl-specific antibodies and optimization of enzymatic reaction. Computational analysis may facilitate the identification of potential methylation sites with ease and provide insight for further experimentation. Here we present a novel protein methylation prediction web server named MeMo, protein methylation modification prediction, implemented in Support Vector Machines (SVMs). Our present analysis is primarily focused on methylation on lysine and arginine, two major protein methylation sites. However, our computational platform can be easily extended into the analyses of other amino acids. The accuracies for prediction of protein methylation on lysine and arginine have reached 67.1 and 86.7%, respectively. Thus, the MeMo system is a novel tool for predicting protein methylation and may prove useful in the study of protein methylation function and dynamics. The MeMo web server is available at: http://www.bioinfo.tsinghua.edu.cn/~tigerchen/memo.html.

Arginine↗
PubMed2006

Hippocampal cell proliferation regulation by repeated stress and antidepressants.

A recent hypothesis suggests reduced hippocampal neurogenesis in depression. Here, we examined cell proliferation in the dentate gyrus and the subventricular zone of rats given repeated stress, a paradigm that prolongs learned helplessness behavior, and whether antidepressants modulate the learned helplessness-associated altered cell proliferation. Decreased cell proliferation, number of clusters, and cells/cluster were noted in the dentate gyrus, but not in the subventricular zone, of learned helplessness rats. Both fluoxetine and desipramine reversed the learned helplessness behavior and increased the cell proliferation and the number of clusters in learned helplessness rats; only fluoxetine did so significantly. Both fluoxetine and desipramine significantly increased the number of cells/cluster. Our results suggest modified hippocampal neurogenesis in prolonged depression and in the mechanism of antidepressant action.

Analysis of Variance↗
PubMed2006

[The correlated research of acute graft versus host disease after allogeneic stem cell transplantation].

OBJECTIVE: To analyze the relationship between the expression of FasL, Perforin and Granzyme B and the development of acute graft versus host disease (aGVHD) after allogeneic hematopoietic stem cell transplantation (allo-HSCT). METHODS: The peripheral blood mRNA expression of granzyme B, perforin, fasL from 17 patients after allo-HSCT was detected by competitive quantitative RT-PCR and the relationship between FasL, Granzyme B and Perforin expressions and clinical symptom of aGVHD was analyzed. RESULTS: The expression level of Granzyme B, Perforin and FasL was 4.6 +/- 0.2, 4.5 +/- 0.1, 1.4 +/- 0.1 before aGVHD occurrence respectively, and was 98.7 +/- 2.5, 91.8 +/- 3.4, 61.5 +/- 2.2, after the occurrence in 14 patients (P < or = 0.05). Over expressions of Granzyme B, Perforin, and FasL during acute GVHD were detected in 13 of 14, 12 of 14, and 12 of 14 patients respectively. The upregulated expressions occurred prior to clinical symptom of aGVHD. CONCLUSION: The expressions of Granzyme B, Perforin, and FasL were significantly high in patients with acute aGVHD. Monitoring of the expressions, might predict the occurrence of clinical aGVHD and it severity and prognosis.

Acute Disease↗
PubMed2006

[Effectiveness of allogeneic peripheral blood stem cell transplantation in 23 patients with myelodysplastic syndromes].

OBJECTIVE: To analyse the outcome of allogeneic peripheral blood stem cell transplantation (allo-PBSCT) for myelodysplastic syndromes (MDS). METHODS: Twenty-three patients with MDS received G-CSF mobilized HLA-identical sibling allo-PBSCT. The numbers of mononuclear cells (MNC) and CD34+ cells were 8. 25 (4.50 -22.36) x 10(8)/kg and 5.59 (1.57 - 12.22) x 10(6)/kg respectively. CsA and shorten course MTX were used for graft-versus-host disease (GVHD) prophylaxis and MMF was given on + 1 d - +28 d posttransplantation. RESULTS: Among 23 patients, 22 achieved hematopoietic recovery. The median time of ANC > 1.0 x 10(9)/L and BPC > 50 x 10(9)/L were + 13 (+ 11 - +17) days and + 30 (+13 + 102) days respectively. Two patients died of transplant related complications and three died of disease relapse, while 18 patients survived. Kaplan-Meier analysis showed disease free survival and relapse rate were (77.8 +/- 8.7)% and (14.4 +/- 7.5)% respectively. CONCLUSION: Allo-PBSCT is an effective treatment for MDS patients.

Adolescent↗
PubMed2005

CTKPred: an SVM-based method for the prediction and classification of the cytokine superfamily.

Cell proliferation, differentiation and death are controlled by a multitude of cell-cell signals and loss of this control has devastating consequences. Prominent among these regulatory signals is the cytokine superfamily, which has crucial functions in the development, differentiation and regulation of immune cells. In this study, a support vector machine (SVM)-based method was developed for predicting families and subfamilies of cytokines using dipeptide composition. The taxonomy of the cytokine superfamily with which our method complies was described in the Cytokine Family cDNA Database (dbCFC) and the dataset used in this study for training and testing was obtained from the dbCFC and Structural Classification of Proteins (SCOP). The method classified cytokines and non-cytokines with an accuracy of 92.5% by 7-fold cross-validation. The method is further able to predict seven major classes of cytokine with an overall accuracy of 94.7%. A server for recognition and classification of cytokines based on multi-class SVMs has been set up at http://bioinfo.tsinghua.edu.cn/~huangni/CTKPred/.

Algorithms↗
PubMed2005

Ionic effects on overstretching transition of B-DNA.

A three-dimensional model is proposed herein to study the ionic effects of a NaCl solution on the overstretching transition of long B-DNA molecules. In this model, the bending deformations of DNA backbones, cooperativity of base-stacking interactions, electrostatic interactions, and spatial effects of the DNA double-helix structure are taken into account. The energy of electrostatic interactions is given as a function of the ionic strength and of the folding angle based on the Poisson-Boltzmann equation. An expression is derived, which shows that the overstretching force is linear with the natural logarithm of the ionic strength. The analytical results of this model are in good agreement with recently reported experimental results.

Biophysical Phenomena↗
PubMed2005

[Effect of human bone marrow mesenchymal stem cell on allogeneic T lymphocyte phenotype in vitro].

The purpose was to study the effect of mesenchymal stem cell (MSC) on immune function, and to explore the new strategy to prevent graft versus host disease (GVHD) and host versus graft reaction (HVGR) in allogeneic bone marrow transplantation. MSCs from human bone marrow cells were isolated and cultured. The purity of MSCs were identified with the spindle-fibroblastic morphological characterization by microphotography, and the phenotypes were tested by flow cytometry. MSCs were planted in 6-well plates (8 x 10(4)/well for group A, 4 x 10(4)/well for group B and 2 x 10(4)/well for group C), and cocultured for 7 days with T cell isolated from peripheral blood. Peripheral blood T cells non-cocultured with MSC acted as the control group. CD3, CD4, CD8, and CD25 expressed on T cells were analyzed by flow cytometry after coculture with MSCs for 0, 24, 72 hours and 7 days respectively. The results showed that CD4(+)CD25(+) T cells and CD8(+) T cells of allogeneic T lymphocytes cocultured with bone marrow MSCs (group A and group B) increased obviously as compared with control group (T lymphocytes uncocultured with MSCs), and there were no difference between groups A and B. CD3, CD4, CD8 and CD25 expressed on T cells had no significant difference between experimental groups and control group. The result suggested that CD4(+)CD25(+)-regulatory T cells and CD8(+) T cells were increased apparently when cocultured with allogeneic MSCs. It is concluded that MSCs pretreatment may be useful in the prevention of GVHD and HVGR in allogeneic bone marrow transplantation and provides a new strategy to induce transplantation tolerance.

Bone Marrow Cells↗
PubMed2005

[Clinical study on anti-leukemia effect mediated by dentritic cells].

Immunotherapy of tumor is extensively attentioned as an important part of combined therapy of tumor in recent years. Dendritic cell (DC) is the most powerful antigen presenting cell (APC) by now which not only activates auto-immunity to attack tumor cells, but also does help to enhance antitumor effect for allogenic bodies. To explore the feasibility and safety of clinical therapy application of peripheral blood derived DC cultured ex vivo, and analyze the influence of DC-inducing-immunotherapy upon long-term survival of ANLL patients accepted autologous bone marrow transplantation, peripheral blood mononuclear cells (PBMNC) of 13 ANLL patients after autologous bone marrow transplantation were collected by using CS3000Plus. DC immunotherapy was administered after cultivation of PBMNC ex vivo for 2 weeks, desease-free survival time was observed after therapy for long time follow-up. The results showed that no any severe adverse event associated with DC therapy was observed, the survival analysis of Kaplan-Meier suggested that five year survival rate was 75.52% in DC group while 45.71% in non-DC group. DC group surpassed non-DC group in accumulative survival rate. It is concluded that the ex vivo cultivation and clinical therapy application of DC derived from peripheral blood are feasible and safe, DC immunotherapy in patients with acute non-lymphocytic leukemia after autologous bone marrow transplantation prolongs desease-free survival time and enhances long-term survival rate.

Adolescent↗
PubMed2005

[The effect of MSC on cytokine production by naive T cell differentiated in vitro].

OBJECTIVE: To investigate the effect of mesenchymal stem cell (MSC) on naive T cell and to explore its mechanism of immunoregulation. METHODS: After culturing for 3 passages, MSC was incubated with naive T cells differentiated from cord blood CD34(+) cells in vitro. Variance of cytokine produced by naive T cell in culture supernatant was analyzed by enzyme-linked immunoassays. RESULTS: On the 7th day of co-culture, a mild proliferation of T cells in the co-culture group was observed: (9.15 +/- 0.68) x 10(5)/well in MSCs + naive T cells group versus (4.87 +/- 1.33) x 10(5)/well in naive T cells alone group (P < 0.05). IFN-gamma production was lower in MSCs + naive T cells group than that in naive T cells alone group: (1.147 +/- 0.181) pg/ml versus (4.897 +/- 0.189) pg/ml (P < 0.05), but IL-2 production was higher in the co-culture group: (16.141 +/- 2.729) pg/ml versus (2.551 +/- 0.460) pg/ml (P < 0.05). Neither IL-4 nor IL-10 were detected. CONCLUSIONS: MSC have allogeneic effect on naive T cell, but may suppress alloreactive T lymphocyte and reduce the incidence of GVHD partly by decreased IFN-gamma production. The result may provide new clues for explaining immunoregulatory mechanism of MSC.

Bone Marrow Cells↗
PubMed2005

[The role of CD25 antibody in unrelated hematopoietic stem cell transplantation].

OBJECTIVE: To explore the role of CD(25) antibody on engraftment and graft-versus-host disease (GVHD) prophylaxis in unrelated hematopoietic stem cell transplantation (UHSCT). METHODS: CD(25) 1 mg/kg was given on day 1, day 4 post-transplantation in 27 patients of UHSCT. RESULTS: Hematopoietic recovery was obtained in 26 patients. One patient died before hematopoietic recovery. Acute GVHD occurred in 17 patients and 6 patients with II or more than degree acute GVHD (23%). Three patients experienced relapse and other 3 patients with serious infection. In these 26 eligible patients, 19 patients got disease free survival. CONCLUSIONS: CD(25) antibody plays an important role on engraftment and GVHD prophylaxis in the treatment of UHSCT and does not increase rate of leukemia relapse. It provides a way of GVHD prophylaxis in unrelated and HLA mismatched hematopoietic stem cell transplantation.

Adolescent↗
PubMed2005

[Experimental study of T lymphocyte reactivity inhibited by allogeneic bone marrow mesenchymal stem cells].

OBJECTIVE: To address the question whether bone marrow mesenchymal stem cells (MSCs) could lower responsiveness of allogeneic T lymphocytes against alloantigens, and explore a feasible strategy for prevention of graft versus host disease (GVHD) occurred in allogeneic bone marrow transplantation. METHODS: T cells were co-cultured with (60)Co-irradiated bone marrow MSCs from different individuals. The proliferative activity of T cells and their reactivity to allogeneic cells and ConA were evaluated with (3)H-TdR incorporation assay. RESULTS: T cells could not be activated upon primary or even secondary exposure to allogeneic MSCs (compared the CPM value of 27,529 +/- 969 of T cell alone with that of primary and secondary exposures to allogeneic MSCs were 9,126 +/- 654 and 13,260 +/- 874, respectively). When MSCs were induced to express HLA-DR, they still could not elicit T cell activation. The proliferation rate of allogenous T cells exposed to MSCs was dramatically declined when T cells from the same donor's MSCs were used as stimulator (CPM value decreased from 45,876 +/- 5285 before coculture to 9850 +/- 1618 after coculture). Furthermore, the results remained unchanged even ConA was added into the culture system. CONCLUSIONS: Heterogenetic MSCs could suppress T cell activation. MSCs pretreatment might be useful in the prevention of GVHD in HLA-mismatched bone marrow transplantation.

Bone Marrow Cells↗
PubMed2004

Orientational orders of small anisotropic molecules confined in slit pores.

Based on a constant-pressure Monte Carlo molecular simulation, we have studied orientationally ordered transitions of small anisotropic molecules confined in two parallel hard walls. These molecules are modeled by the hard Gaussian overlap model. The molecular elongations of the chosen molecules are so small that the molecules cannot form stable liquid-crystal (LC) phases in the bulk. But in the slit pores, we found, while the distance between two walls of the pores decreases to the molecular scale, an orientationally ordered phase can form. It shows that even hard confining surfaces favor the alignment of the small anisotropic molecules. Thus we conclude that the required molecular elongation for forming LC phases will decrease in confinement. Our results indicate that some non-LC small molecules may form stable LC phases due to the inducement of confining surfaces.

Journal Article↗