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Biomedical subjects

Yan Jin

Publications and source records attributed to Yan Jin.

At least 19 recordsLinked to original sources
PubMed2026

Prognostic impact of CEACAM5 in nonsquamous non-small cell lung cancer: a critical reappraisal driven by cut-off optimization.

BACKGROUND: Carcinoembryonic antigen-related cell adhesion molecule 5 (CEACAM5) has emerged as a promising therapeutic target for antibody-drug conjugates (ADCs) in nonsquamous non-small cell lung cancer (NSCLC). However, the landscape of CEACAM5 protein expression and its association with clinicopathological features in nonsquamous NSCLC remain poorly characterized. This study represents the first comprehensive investigation to profile CEACAM5 protein expression in this specific population using a clinical-grade immunohistochemistry (IHC) assay. METHODS: We retrospectively analyzed 218 patients with resected nonsquamous NSCLC. A standardized IHC assay derived from a clinical trial was employed, utilizing a proprietary monoclonal antibody (clone 769) specifically developed for clinical application. We systematically evaluated the relationship between CEACAM5 expression and tumor characteristics using both a conventional therapeutic threshold (≥50%) and a sensitive data-driven cut-off (>0%) to explore the full spectrum of antigen expression. RESULTS: The assay demonstrated excellent reproducibility. We found that CEACAM5 expression was significantly associated with markers of tumor aggressiveness, including lymphovascular and pleural invasion. Notably, the sensitive >0% cut-off revealed broader biological correlations than the restrictive ≥50% threshold. While CEACAM5 was not an independent prognostic factor in the overall cohort, a stage-specific, hypothesis-generating analysis-supported by external genomic validation-suggested that positive CEACAM5 expression may be associated with a trend towards poorer disease-free survival specifically in early-stage (stage I-II) patients, although this did not reach statistical significance (P=0.06). CONCLUSIONS: This study provides the first detailed characterization of CEACAM5 protein expression in nonsquamous NSCLC, establishing it as a biomarker linked to aggressive disease phenotypes. Our findings suggest that adopting a sensitive detection threshold (>0%) may better capture the population of patients with biologically active CEACAM5, thereby potentially refining candidate selection for targeted therapies and risk stratification in early-stage disease, a hypothesis that warrants prospective validation.

Carcinoembryonic antigen-related cell adhesion mol↗
PubMed2026

Uncovering metabolite-immune interactions in the pathogenesis of psoriatic arthritis: A 2-sample Mendelian randomization study.

PsA is a chronic inflammatory joint condition associated with psoriasis, and its underlying mechanisms are not fully elucidated. Serum metabolites, as direct reflections of metabolic status, may influence disease progression by regulating immune cell function; however, the causal relationships and specific pathways require further investigation. The present investigation utilized a 2-sample bidirectional MR methodology, leveraging extensive pooled GWAS data to thoroughly evaluate the causal relationships between 1440 serum metabolites and PsA. Additionally, mediation MR analysis was performed to explore the possible mediating effects of 731 immune cell characteristics. In the primary analysis, inverse-variance weighted was employed, and this was further supported by various sensitivity analyses to confirm the reliability of the findings. The genetic method to infer causality analysis revealed significant positive causal associations between 10 serum metabolites and PsA risk, with quinolinate levels demonstrating the most significant correlation (OR = 1.56, 95% CI: 1.26-1.93); while 4 metabolites (e.g., citrate levels, OR = 0.74, 95% CI: 0.61-0.89) exhibited protective effects. Regarding immune cells, 6 cellular features (e.g., CD20 on B cells) were positively correlated with disease risk, whereas 5 features (primarily HLA-DR expression on monocyte subsets) showed negative correlations. Mediation analysis identified 3 significant pathways,the percentage of the effect explained by the mediator: N6,N6,N6-trimethyllysine levels mediated via B cells (CD20 on IgD+ CD38br), with a proportion of 33.2%; 1-stearoyl-2-docosahexaenoyl-GPE (18:0/22:6) levels mediated through monocytes (HLA-DR on CD14- CD16-) with a 32.0% proportion; the unknown metabolite X-24736 also mediated 42.1% of the protective effect via the same monocyte phenotype. This study revealed that elevated amino acid-related metabolites and glycerophospholipids significantly increase PsA risk through immune cell effects. These are closely associated with PsA pathogenesis and may serve as potential biomarkers. The novel findings underscore metabolic-immune interactions as targets for biomarkers and therapies in PsA, advancing personalized medicine.

Humans↗
PubMed2026

Third-generation whole-genome sequencing reveals the role of CNTNAP2 as a tumor suppressor gene in high-risk neuroblastomas.

BACKGROUND: Neuroblastoma is a common and aggressive pediatric sympathetic nervous system tumor. Genomic structural variants (SVs) contribute substantially to neuroblastoma, yet remain under-characterized in high-risk neuroblastomas. We aimed to elucidate neuroblastoma pathogenesis using third-generation whole-genome sequence high-risk cases to identify driver aberrations and explore potential therapeutic strategies. METHODS: We analyzed third-generation whole-genome sequencing data of 20 high-risk neuroblastoma samples and combined the findings with those obtained from the analysis of clinical samples, in vitro models, and public datasets. RESULTS: The contactin-associated protein-like 2 (CNTNAP2) gene was observed to be frequently aberrated because of structural variants in high-risk neuroblastoma samples. CNTNAP2 expression was significantly correlated with favorable histology and could be used to predict prognosis using clinical samples and neuroblastoma datasets. Overexpression and knockdown experiments and transcriptomic analysis revealed that CNTNAP2 was primarily involved in neuronal differentiation and axon guidance pathways; moreover, CNTNAP2 was required for neuroblastoma differentiation and affected cancer stemness. Immunoprecipitation and mass spectrometry revealed that CNTNAP2 interacted with cytoskeletal proteins like drebrin 1 (DBN1) and myosin-heavy chain 9 (MYH9). CNTNAP2 dynamically reorganises actin and microtubules for DBN1-mediated neuronal differentiation. CNTNAP2 also reduces CTNNB1 transcription and β-catenin pathway activation by inhibiting MYH9 nuclear translocation. CNTNAP2 overexpression in neuroblastoma cell lines resulted in cell cycle arrest, decreased cell proliferation and metastasis. CONCLUSIONS: The recurrent loss of CNTNAP2 in neuroblastoma contributes to an aggressive phenotype by impairing neuronal differentiation and increasing cancer stemness. These findings may serve as a foundation for developing therapeutic strategies to overcome barriers to differentiation.

Humans↗
PubMed2024

Fragmentomics of plasma mitochondrial and nuclear DNA inform prognosis in COVID-19 patients with critical symptoms.

BACKGROUND: The mortality rate of COVID-19 patients with critical symptoms is reported to be 40.5%. Early identification of patients with poor progression in the critical cohort is essential to timely clinical intervention and reduction of mortality. Although older age, chronic diseases, have been recognized as risk factors for COVID-19 mortality, we still lack an accurate prediction method for every patient. This study aimed to delve into the cell-free DNA fragmentomics of critically ill patients, and develop new promising biomarkers for identifying the patients with high mortality risk. METHODS: We utilized whole genome sequencing on the plasma cell-free DNA (cfDNA) from 33 COVID-19 patients with critical symptoms, whose outcomes were classified as survival (n = 16) and death (n = 17). Mitochondrial DNA (mtDNA) abundance and fragmentomic properties of cfDNA, including size profiles, ends motif and promoter coverages were interrogated and compared between survival and death groups. RESULTS: Significantly decreased abundance (~ 76% reduction) and dramatically shorter fragment size of cell-free mtDNA were observed in deceased patients. Likewise, the deceased patients exhibited distinct end-motif patterns of cfDNA with an enhanced preference for "CC" started motifs, which are related to the activity of nuclease DNASE1L3. Several dysregulated genes involved in the COVID-19 progression-related pathways were further inferred from promoter coverages. These informative cfDNA features enabled a high PPV of 83.3% in predicting deceased patients in the critical cohort. CONCLUSION: The dysregulated biological processes observed in COVID-19 patients with fatal outcomes may contribute to abnormal release and modifications of plasma cfDNA. Our findings provided the feasibility of plasma cfDNA as a promising biomarker in the prognosis prediction in critically ill COVID-19 patients in clinical practice.

Humans↗
PubMed2006

Regulation of the human growth hormone gene family: possible role for Pit-1 in early stages of pituitary-specific expression and repression.

The somatic cells of a multicellular organism contain an identical complement of genes that need to be expressed specifically and appropriately to allow the normal development and functions associated with an organism. In the eukaryotic cell nucleus, genes are packaged with nucleoprotein histones into chromatin. The human growth hormone (GH)/chorionic somatomammotropin (CS) gene family offers an excellent model to study the relationship between chromatin structure and transcription factor binding in terms of tissue-specific gene expression. The GH/CS gene family consists of five genes (GH-N, GH-V, CS-A, CS-B and CS-L), contained in a single locus on chromosome 17. Although they share approximately 94% sequence similarity, GH-N expression is restricted to pituitary somatotropes while the four placental GH/CS genes are expressed in the villus syncytiotrophoblast. Appropriate expression in vivo is dependent on remote sequences found 14-32 kb upstream of GH-N in the loci of adjacent genes, and these sequences are characterized by five (I-V) nuclease-hypersensitive sites (HS). Pituitary-specific factor Pit-1 binds at HS I/II and plays an essential role in chromatin remodeling and GH-N expression; however, the processes that lead to HS I/II accessibility are unknown. We discuss the possibility that Pit-1-driven remodeling at HS III may precede that at HS I/II in the pituitary. Also, in pituitary chromatin, all five GH/CS genes share similar nuclease sensitivity, suggesting that the conformation of the placental genes is not inhibitory to transcription. Given that the promoters of both GH-N and the placental GH/CS genes contain Pit-1-binding sites, possible mechanisms to restrict placenta GH/CS promoter activity in the pituitary are discussed, including active repression via P sequences located upstream of each of the placental GH/CS genes. Positively or negatively influencing those components known to be important for pituitary transcription may link epigenetic events to key transcription factors in the overall picture of tissue-specific control of gene expression.

Chromatin Assembly and Disassembly↗
PubMed2006

Not polymorphism but methylation of class II transactivator gene promoter IV associated with persistent HBV infection.

BACKGROUND: Class II transactivator (CIITA) is the major rate-limiting regulator for expression of class II major histocompability complex (MHC-II). Human CIITA gene expression is controlled by four distinct promoters (pIto pIV). OBJECTIVE: To evaluate the relationship among polymorphism and methylation status of CIITA gene promoters and persistent hepatitis B virus (HBV) infection. METHODS: We recruited 21 patients with hepatocellular carcinoma (HCC), 45 liver cirrhosis (LC), 65 chronic hepatitis B (CHB), 26 acute hepatitis B (AHB) and 95 healthy blood donors. Polymorphism of CIITA gene promoters was assayed by PCR-SSCP-sequencing. Bioinformatics analysis was employed to predict the existence of CpG islands. Methylation-specific PCR (MSP) was used to detect the methylation status of CIITA gene pIV. RESULTS: No sequence differences were observed at CIITA genes pI, III and IV among HCC, LC, CHB, AHB patients and healthy controls. No CpG islands were found in the pI, pII and pIII sequences, but there was a CpG island in pIV. The frequency of methylated POV was not significantly different within persistent HBV infection groups (patients with HCC, LC or CHB). Significance was found between the persistent infection group and acute HBV infection or healthy controls. CONCLUSIONS: CIITA gene promoter sequences are conserved. PIV is highly methylated and associated with host susceptibility to HBV persistent infection.

DNA Methylation↗
PubMed2006

Mitogen-activated protein kinases inhibit the ROMK (Kir 1.1)-like small conductance K channels in the cortical collecting duct.

It was demonstrated previously that low dietary potassium (K) intake stimulates Src family protein tyrosine kinase (PTK) expression via a superoxide-dependent signaling. This study explored the role of mitogen-activated protein kinase (MAPK) in mediating the effect of superoxide anions on PTK expression and ROMK (Kir 1.1) channel activity. Western blot analysis demonstrated that low K intake significantly increased the phosphorylation of P38 MAPK (P38) and extracellular signal-regulated kinase (ERK) but had no effect on phosphorylation of c-JUN N-terminus kinase in renal cortex and outer medulla. The stimulatory effect of low K intake on P38 and ERK was abolished by treatment of rats with tempol. The possibility that increases in superoxide and related products that are induced by low K intake were responsible for stimulating phosphorylation of P38 and ERK also was supported by the finding that application of H(2)O(2) increased the phosphorylation of ERK and P38 in the cultured mouse collecting duct cells. Simultaneous blocking of ERK and P38 completely abolished the effect of H(2)O(2) on c-Src expression in mouse collecting duct cells. For determination of the role of P38 and ERK in the regulation of ROMK-like small-conductance K (SK) channels, the patch-clamp technique was used to study the effect of inhibiting P38 and ERK on SK channels in the cortical collecting duct from rats that were on a control K diet (1.1%) and on a K-deficient diet for 1 d. Inhibition of ERK, c-JUN N-terminus kinase, or P38 alone had no effect on SK channels. In contrast, simultaneous inhibition of P38 and ERK significantly increased channel activity. The effect of inhibiting MAPK on SK channels was not affected in the presence of herbimycin A, a PTK inhibitor, and was larger in rats that were on a K-deficient diet than in rats that were on a normal-K diet. However, the stimulatory effect of inhibiting ERK and P38 on SK was absent in the cortical collecting duct that was treated with colchicine. It is concluded that low K intake-induced increases in superoxide levels are responsible for stimulation of P38 and ERK and that MAPK inhibit the SK channels by stimulating PTK expression and via a PTK-independent mechanism.

Adrenal Cortex↗
PubMed2006

Identification and characterization of a novel gene, Mcpr1, and its possible function in the proliferation of embryonic palatal mesenchymal cells.

We cloned a novel mouse cDNA, Mcpr1 (mouse cleft palate-related gene 1), between retinoic acid (RA)-treated murine embryonic palatal and control shelves by improved subtractive hybridization. Its transcript was identified by Northern blotting. The open reading frame encodes 132 amino acids and shows almost no identity to other genetic products. Mcpr1 expression could be detected extensively in adult mouse tissues and during murine embryonic development. It was identified to be significantly stimulated by RA in murine palatal shelves at embryonic day 12 and in palatal mesenchymal cells in vitro. We demonstrate that MCPR1 protein was localized primarily in the cytoplasm and could be synthesized and secreted by transfected COS-7 cells. Both the secretory and recombinant proteins of Mcpr1 inhibited proliferation of murine embryonic palatal mesenchymal cells and impeded the progression from the G1 to S phase in the cell cycle. The cells were prone to apoptosis after exposure to glutathione S-transferase-MCPR1. Furthermore, knockdown of MCPR1 protein levels by antisense oligodeoxynucleotides promoted progression of cells from the G1 to S phase and completely abolished the RA-induced block of the cell cycle from the G1 to S phase. These findings suggest that Mcpr1 might function as one of the RA-up-regulated genes involved in inhibiting cell proliferation during palatogenesis and RA-induced cleft palate by regulating proliferation and apoptosis of embryonic palatal mesenchymal cells and might even play a role in the development of many other organs.

Adaptor Proteins, Signal Transducing↗
PubMed2006

Transport of coliphage in the presence and absence of manure suspension.

Mechanisms of coliphage transport and fate in the presence and absence of manure suspension were studied in saturated column experiments. In the presence of manure suspension, little inactivation of indigenous somatic coliphage occurred and the transport was controlled by deposition. The deposition followed a power law distribution with depth, and the magnitude increased with decreasing sand size. Comparison of the cumulative size distribution of manure components in the suspension initially and after passage through sand, suggested that particles retained by mechanical filtration and/or straining decreased the effective pore size and potentially induced straining of the somatic coliphage. A 2-site kinetic deposition model was used to estimate the magnitudes of attachment and straining in the presence of manure suspension, and provided a good description of the data. Modeling results indicated that straining accounted for 16 to 42% of the deposited somatic coliphage, and that both straining and attachment increased with decreasing sand size due to smaller pores and higher surface area, respectively. In the absence of manure suspension, phiX174 (a representative somatic coliphage) and MS2 (a male-specific RNA coliphage) transport was controlled by inactivation induced by the solid phase. This conclusion was based on comparison of coliphage transport behavior at 5 and 20 degrees C, mass balance information, and numerical modeling. Comparison of somatic coliphage transport data in the presence and absence of manure suspension revealed much higher effluent concentrations in the presence of manure. This difference was attributed to lower inactivation and higher detachment rates. The observed coliphage transport behavior suggests that survival of viruses may be extended in the presence of manure suspensions, and that transport studies conducted in the absence of manure suspension may not accurately characterize the transport potential of viruses in manure-contaminated environments.

Animals↗
PubMed2006

Interfacial interactions and colloid retention under steady flows in a capillary channel.

Colloidal interfacial interactions in a capillary channel under different chemical and flow conditions were studied using confocal microscopy. Fluorescent latex microspheres (1.1 microm) were employed as model colloids and the effects of ionic strength and flow conditions on colloidal retention at air-water interface (AWI) and contact line were examined in static and dynamic (flow) experiments. Colloids were preferentially attached to and accumulated at AWI, but their transport with bulk solution was non-negligible. Changing solution ionic strength in the range 1-100 mM had a marginal effect on colloidal accumulation, indicating forces other than electrostatic are involved. Flow through the open channel resembled Poiseuille flow with AWI acting as a non-stress-free boundary, which resulted in near stagnation of AWI and consequently promoted colloid accumulation. Retention on contact line was likely dominated by film-straining and was more significant in flow relative to static experiments due to hydrodynamic driving force. Modeling and dimensionless analysis of the flow behavior in the capillary channel clearly indicate the important role of apparent surface viscosity and surface tension in colloidal interfacial retention at the pore scale, providing insight that could improve understanding of colloid fate and transport in natural unsaturated porous media.

Colloids↗
PubMed2006

The role of bone morphogenetic protein-2 in vivo in regeneration of peripheral nerves.

We investigated the effects of bone morphogenetic protein-2 (BMP-2) and some other BMPs on regeneration of peripheral motor nerves in vivo. The facial nerves of 24 New Zealand rabbits were crushed to examine a series of retrograde changes in the facial nuclei and axons, in what has been called the "axon reaction". The facial nerves of the experimental group were treated with epineurial coaptation and BMP-2 after the injury. Nerves not treated with BMP-2 were regarded as controls. The expression of BMP-2 was investigated by in situ hybridisation in the neurons of facial nuclei. The electrophysiology, image analysis and transmission electron microscopy were used to evaluate the level of the recovery of facial nerves. The results showed that the axons in the experimental group were thicker and denser than those in the control group four weeks later. The expression of BMP-2 in the neurons of facial nuclei increased after injury. The electron microscopic observations showed that the axons' degeneration in the experimental group was less than that in the control group. Despite the morphological difference between the two groups, there was no apparent difference between them in nerve conduction velocity. These findings suggest that BMP-2 might be involved in the regeneration of facial nerves, and might function as a potential neurotrophic factor.

Animals↗
PubMed2006

In situ amplified chemiluminescent detection of DNA and immunoassay of IgG using special-shaped gold nanoparticles as label.

BACKGROUND: Au(III) catalyzed luminol chemiluminescence (CL) is classic in luminescence analysis. Recently, spherical gold nanoparticles (Au-NPs) were found displaying far stronger catalytic activity on luminol CL than that of Au(III). Some methods based on Au-NPs probes have been developed for DNA detection or immunoassay. However, more complicated labeling or stripping procedures are often inescapable in these protocols. METHODS: We synthesized specially shaped, irregular gold nanoparticles (IGNPs) and found their catalytic efficiency on luminol CL to be 100-fold greater than that of spherical Au-NPs. Using the IGNPs-functionalized DNA oligomers and the IGNPs-modified anti-IgG as in situ chemiluminescent probes, we established sandwich-type analytic methods for rapid, simple, selective, and sensitive sequence-specific DNA detection and for human plasma IgG immunoassay, respectively. We used 12 clinical human plasma samples to examine the precision and accuracy of the proposed method for IgG content determination. RESULTS: Calibration curves for the oligonucleotide [DeltaI = 15.73 + 27.55 (DNA) x 10(10) (mol/L); R(2) = 0.9936] and IgG [DeltaI = 48.84 + 30.23 (IgG) x 10(10) (mol/L); R(2) = 0.9964] show good correlation, demonstrating the linear response over the concentrations tested (0.04-10 nmol/L for DNA, 0.05-10 nmol/L for IgG). The limit of detection, calculated based on 50 microL of a solution of calibrators, was 13 pmol/L for DNA and 17 pmol/L for IgG, with a signal-to-noise ratio of 3. We obtained good intra-and interassay reproducibility. The IgG contents in 12 human plasma samples obtained by the proposed method are identical with the data of clinical laboratory. CONCLUSIONS: We developed a simple and sensitive method for in situ amplified chemiluminescence detection of sequence-specific DNA and immunoassay of IgG by use of highly active, specially shaped, irregular gold nanoparticles (IGNPs) as label and confirmed by clinical samples test. This method has many desirable features including rapid detection, selectivity, and little required instrumentation. This new protocol may be quite promising, with potentially broad applications for clinical immunoassays and DNA hybridization analysis.

Catalysis↗
PubMed2006

Low Na intake suppresses expression of CYP2C23 and arachidonic acid-induced inhibition of ENaC.

We previously demonstrated that arachidonic acid (AA) inhibits epithelial Na channels (ENaC) through the cytochrome P-450 (CYP) epoxygenase-dependent pathway (34). In the present study, we tested the hypothesis that low Na intake suppresses the expression of CYP2C23, which is mainly responsible for converting AA to epoxyeicosatrienoic acid (EET) in the kidney (11) and attenuates the AA-induced inhibition of ENaC. Immunostaining showed that CYP2C23 is expressed in the Tamm-Horsfall protein (THP)-positive and aquaporin 2 (AQP2)-positive tubules. This suggests that CYP2C23 is expressed in the thick ascending limb (TAL) and collecting duct (CD). Na restriction significantly suppressed the expression of CYP2C23 in the TAL and CD. Western blot also demonstrated that the expression of CYP2C23 in renal cortex and outer medulla diminished in rats on Na-deficient diet (Na-D) but increased in those on high-Na diet (4%). Moreover, the content of 11,12-epoxyeicosatrienoic acid (EET) decreased in the isolated cortical CD from rats on Na-D compared with those on a normal-Na diet (0.5%). Patch-clamp study showed that application of 15 microM AA inhibited the activity of ENaC by 77% in the CCD of rats on a Na-D for 3 days. However, the inhibitory effect of AA on ENaC was significantly attenuated in rats on Na-D for 14 days. Furthermore, inhibition of CYP epoxygenase with MS-PPOH increased the ENaC activity in the CCD of rats on a control Na diet. We also used microperfusion technique to examine the effect of MS-PPOH on Na transport in the distal nephron. Application of MS-PPOH significantly increased Na absorption in the distal nephron of control rats but had no significant effect on Na absorption in rats on Na-D for 14 days. We conclude that low Na intake downregulates the activity and expression of CYP2C23 and attenuates the inhibitory effect of AA on Na transport.

8,11,14-Eicosatrienoic Acid↗
PubMed2006

ADAM28 participates in the regulation of tooth development.

Disintegrin and metalloprotease (ADAM) proteins are a family of membrane-anchored glycoproteins with diverse functions in fertilisation, development, neurogenesis and protein ectodomain shedding. ADAM28 is a newly discovered member of the ADAM family in humans and murine with autocatalytic activity. Recently, the authors screened ADAM28 genes from patients with congenital hypoplasia of tooth root, and studied the relationship between ADAM28 and tooth development. A polyclonal antibody (pAb) against ADAM28 was preparared, and the expression and localisation of ADAM28 were detected in tooth germ and dental mesenchymal cells. The results indicated that the prokaryotic expression vector pGEX-4T-ADAM28 was constructed successfully. Glutathione S-transferase-ADAM28 fusion protein was generated after inducement by isopropylthio-beta-d-galactoside and isolated by sodium dodecyl sulphate-polyacrylamide gel electrophoresis. The purified fusion protein was used as an antigen for production of antibody. Western blot and enzyme-linked immunosorbent assay analyses verified that the antibody had a high specificity and titre. Immunohistochemistry and reverse transcriptase-polymerase chain reaction showed that ADAM28 was expressed at each stage of tooth germ development at different levels. Moreover, it was expressed in human dental follicle cells, human dental papilla cells, human dental pulp stem cells, human periodontal ligament cells and human dental cervical loop epithelial cells at transcription level. In conclusion, it is reasonable to suggest that ADAM28 may participate in tooth development and the regulation of odontogenic mesenchymal cells through progressive reciprocal inductive interactions between the epithelium and the mesenchyme.

ADAM Proteins↗
PubMed2006

Hairpin DNA probe based electrochemical biosensor using methylene blue as hybridization indicator.

In this paper, a label-free, rapid and simple method was proposed to study the hybridization specificity of hairpin DNA probe using methylene blue (MB) as a hybridization indicator. Thiolated hairpin DNA probe was immobilized on the gold electrode by self-assembly. The voltammetric signals of MB were investigated at these modified electrodes by means of cyclic voltammetry (CV) detection. Single-base mutation oligonucleotide and random oligonucleotide can be easily discriminated from complementary target DNA. The effect of mismatch position in target DNA was investigated. Experimental results showed that mutation in the center of target DNA had greatest effect on the hybridization with hairpin DNA probe. The relationship between electrochemical responses and DNA target concentration was also studied. The reduction current of MB intercalation decreased with increasing the concentration of target DNA. Taken together, these experiments demonstrate that the hybridization indicator MB provides great promise for rapid and specific measurement of target DNA.

Biosensing Techniques↗
PubMed2006

Enhancement of periodontal tissue regeneration by locally controlled delivery of insulin-like growth factor-I from dextran-co-gelatin microspheres.

The present work focused on the design of novel hydrogel microspheres based on both dextran- and gelatin-derived biomaterials, and discussed whether locally controlled delivery of IGF-I from dextran-co-gelatin hydrogel microspheres (DG-MP) was useful for periodontal regeneration enhancement. Microspheres were synthesized when gelatin was cooperating with glycidyl methacrylate (GMA) derivatized dextrans (Dex-GMA) and the resultant DG-MP with a hydrogel character of which the cross-linking density could be controlled by the degree of substitution (DS, the number of methacrylates per 100 glucopyranose residues) of Dex-GMA. In this study, three types of DG-MP (DG-MP4.7, DG-MP6.3 and DG-MP7.8) obtained from gelatin and Dex-GMA (differing in DS: 4.7, 6.3 and 7.8 respectively) were prepared and characterized by swelling and degradation properties, drug release kinetics and biological capability in promoting tissue regeneration. By swelling in aqueous positively charged IGF-I solutions, the protein could be encapsulated in DG-MP by polyionic complexation with negatively charged acidic gelatin. No obvious influence of Dex-GMA's DS on DG-MP's configuration and size was observed, and the release and degraded properties showed no significant difference between three types of DG-MP in PBS buffer either. However, high DS of Dex-GMA could lower microsphere's swelling, prolong its degraded time and minimize IGF-I burst release markedly in dextranase-containing PBS, where IGF-I release from a slow release type of microspheres (DG-MP7.8) could be maintained more than 28 days, and an effective protein release kinetics without a significant burst but a relevantly constant release after the initial burst was achieved. IGF-I in DG-MP resulted in more new bone formation in the periodontal defects within 4 or 8 weeks than IGF-I in blood clot directly did (P < 0.01). The observed newly formation of periodontal tissues including the height and percentage of new bone and new cementum on the denuded root surfaces of the furcation area in DG-MP7.8 group were more than that in other groups (P < 0.05). The adequate width of regenerative periodontal ligament (PDL), regular Sharpey's fibers and alveolar bone reconstruction could be observed only in DG-MP7.8 group. These combined results demonstrate that effective release kinetics can be realized by adjusting the DS of Dex-GMA and followed cross-linking density of DG-MP, and that locally controlled delivery of IGF-I from slow release type of DG-MP may serve as a novel therapeutic strategy for periodontal tissue regeneration.

Animals↗
PubMed2006

Cell pellets from dental papillae can reexhibit dental morphogenesis and dentinogenesis.

We isolated dental papilla mesenchymal cells (DPMCs) from different rat incisor germs at the late bell stage and incubated them as cell pellets in polypropylene tubes. In vitro pellet culture of DPMCs presented several crucial characteristics of odontoblasts, as indicated by accelerated mineralization, positive immunostaining for dentin sialophosphoprotein and dentin matrix protein 1, and expression of dentin sialophosphoprotein mRNA. The allotransplantation of these pellets into renal capsules was also performed. Despite the absence of dental epithelial components, dissociated DPMCs with a complete loss of positional information rapidly underwent dentinogenesis and morphogenesis, and formed a cusp-like dentin-pulp complex containing distinctive odontoblasts, predentin, dentin, and dentinal tubules. These results imply that DPMCs at the late bell stage can reexhibit the dental morphogenesis and dentinogenesis by themselves, and epithelial-mesenchymal interactions at this stage may not be indispensable. Furthermore, different DPMC populations from the similar stage may keep the same developmental pattern.

Animals↗