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Biomedical subjects

Jie Ding

Publications and source records attributed to Jie Ding.

At least 37 records · Page 2Linked to original sources
PubMed2005

Helicobacter pylori specific immune response induced by conservative flagellin linear B-cell epitope.

AIM: To testify the immunogenicity of a conservative B-cell linear epitope of Helicobacter pylori (H pylori) flagellin A. METHODS: Different programs were used to analyze the secondary structure, molecular hydropathy, and surface accessibility of H pylori flagellin A. Linear B-cell epitopes were estimated based on the structural and physiochemical information. Analysis of residue divergence was proposed to screen a conservative linear epitope. The 29-peptide (Pep29mer) synthesized by chemical method, including the predicted conservative B-cell epitope and a known K2d compatible T-cell epitope, was used to immunize mice, and then H pylori-specific antibodies were detected by ELISA. RESULTS: Based on the analyses of divergent amino acid residues, structural and physiochemical characteristics, it was strongly suggested that the short fragment NDSDGR was the core of a conservative linear epitope in flagellin A. Animals immunized by Pep29mer acquired efficient immune response. In detail, serum H pylori-specific IgA and IgG1 increased significantly in immunized group, while IgG2a only had an insignificant change. H pylori-specific IgA in gastrointestinal flushing fluid also increased significantly. CONCLUSION: The conservative short fragment NDSDGR is the core of a linear B-cell epitope of flagellin A.

Amino Acid Sequence↗
PubMed2005

Evaluation of ethoxynonafluorobutane as a safe and environmentally friendly solvent for chiral normal-phase LC-atmospheric pressure chemical ionization/electrospray ionization-mass spectrometry.

Coupling normal-phase LC separation methods to atmospheric pressure ionization (API)-mass spectrometry (MS) for detection can be problematic because of the possible detonation hazard and because nonpolar solvents do not support ionization of the analyte. Unlike achiral separations, enantiomeric separations can be very sensitive to small changes in the separation environment. Thus, completely substituting the main mobile phase component of a normal-phase LC solvent for an environmentally friendly, nonflammable fluorocarbon-ether as a safe and effective solvent must be thoroughly evaluated before it can be recommended for enantioselective separations with API-MS detection. Ethoxynonafluorobutane (ENFB) was used as a normal-phase solvent for the enantioselective separation of 15 compounds on two macrocyclic glycopeptide chiral stationary phases (CSPs) and a new polymeric chiral stationary phase. The chromatographic figures of merit were compared between results obtained with the ENFB mobile phases and traditional heptane-based mobile phases. In addition, the limits of detection (LOD) using the API-MS compatible ENFB were examined, as well as flow rate sensitivities and compatibilities with common polar organic modifier. ENFB is a safe and effective solvent for enantioselective normal-phase/API-MS analyses.

Atmospheric Pressure↗
PubMed2005

Chiral ionic liquids: synthesis and applications.

Over the last ten years, interest and publications involving ionic liquids have expanded exponentially. Thus far, they have predominantly been used in organic synthesis and separations. However, their use is rapidly expanding into other areas of science and technology. Research involving chiral ionic liquids has been much more limited and only recently has come to the forefront. In this work, we review the synthesis of chiral ionic liquids and their use. Today, this is an area of research that is poised for rapid development and expansion.

Alkanes↗
PubMed2005

Oral attenuated Salmonella typhimurium vaccine against MG7-Ag mimotope of gastric cancer.

AIM: To develop an oral attenuated Salmonella typhimurium vaccine against gastric cancer and to evaluate its efficacy in mice. METHODS: A complementary sequence of Nco I site and a sequence coding for MG7-Ag mimotope were designed at the 5' terminus of forward primer. Using p1.2 II-HBCAg plasmid as template, PCR was performed to get a fusion gene of the mimotope and a HBcAg gene. The fusion gene was then subcloned into the plasmid pYA3341 complementary to Salmonella typhimurium X4550, and the recombinant plasmid was then transformed into attenuated Salmonella typhimurium X4550. Balb/c mice were orally immunized with the recombinant Salmonella typhimurium X4550. The mice were immunized every 2 wk to reinforce the immunity. At the 6th wk, serum titer of antibody was detected by ELISA, and at the 8th wk, cellular immunity was detected by (51)Cr release test. Ehrlich ascites carcinoma cells expressing MG7-Ag were used in tumor challenge assay as a model to evaluate the protective effect of the vaccine. RESULTS: Serum titer of antibody against MG7-Ag was significantly higher in mice immunized with the vaccine than in control groups (0.9538+/-0.043 vs 0.6531+/-0.018, P<0.01; 0.9538+/-0.043 vs 0.6915+/-0.012, P<0.01), while in vitro (51)Cr release assay of the splenocytes showed no statistical difference in the three groups. Two weeks after tumor challenge, 1 in 5 immunized mice was tumor free, while all the mice in the control group presented tumor. CONCLUSION: Oral attenuated Salmonella typhimurium vaccine against the MG7-Ag mimotope of gastric cancer is immunogenic. It can induce significant humoral immunity against tumors in mice, and has some protective effects.

Administration, Oral↗
PubMed2005

Mutations in NPHS2 in sporadic steroid-resistant nephrotic syndrome in Chinese children.

BACKGROUND: Since the identification of the NPHS2 gene, various investigators have demonstrated that an NPHS2 mutation is a frequent cause of sporadic steroid-resistant nephrotic syndrome (SRNS), and occurs in 10.5-28% of children with the syndrome. Idiopathic nephrotic syndrome (INS) is also the most frequent glomerular disease in Chinese children, of which approximately 20% of cases show steroid resistance. To our knowledge, however, whether or not NPHS2 is the causative gene in Chinese sporadic SRNS has not been established. This study aims to examine mutations in NPHS2 in Chinese children with sporadic SRNS. METHODS: We examined 23 Chinese children with sporadic SRNS for mutations in NPHS2. The mutational analysis of NPHS2 was performed by polymerase chain reaction, denaturing high-performance liquid chromatography and DNA sequencing. RESULTS: A heterozygous missense mutation of L361P in exon 8 of NPHS2 was detected in one of 23 children with sporadic SRNS, whereas it was not found in 53 controls. We also identified seven NPHS2 polymorphisms, -51G>T, 288C>T, IVS3-46C>T, IVS3-21C>T, IVS7-74G>C, 954T>C and 1038A>G, in some patients and controls. There was no significant difference in the genotypic and allelic frequencies of these polymorphisms between the patients and controls. CONCLUSION: The results demonstrate that NPHS2 mutations are also present in Chinese sporadic SRNS. Our investigation supports the necessity of searching for mutations in NPHS2 in Chinese children with sporadic SRNS.

Adolescent↗
PubMed2005

Expression of SARS-coronavirus nucleocapsid protein in Escherichia coli and Lactococcus lactis for serodiagnosis and mucosal vaccination.

The nucleocapsid (N) protein of the severe acute respiratory syndrome (SARS)-associated coronavirus (SARS-CoV) is an important antigen for the early diagnosis of SARS and the development of vaccines. It was expressed in Escherichia coli as a fusion with human glutathione S-transferase (hGST) and was confirmed by Western blotting analysis. This recombinant N protein (hGST-N) was purified and used to measure the SARS-CoV N-specific antibody in the sera of eight SARS patients by enzyme-linked immunosorbent assay. Specific antibody response to this purified recombinant N protein was 100% positive in the SARS patients' sera, while none of the control sera from 30 healthy people gave a positive reaction in the same assay. The SARS-CoV N protein was also expressed in Lactococcus lactis in the cytoplasm or secreted into the medium. The N-producing strain MG1363/pSECN and the purified hGST-N protein were respectively administered to mice, either orally or intranasally. Results indicated that orally delivered MG1363/pSECN induced significant N-specific IgG in the sera. In conclusion, our work provides a novel strategy to produce the SARS-CoV N protein for serodiagnosis and for L. lactis-based mucosal vaccines.

Administration, Intranasal↗
PubMed2005

Use of chiral ionic liquids as solvents for the enantioselective photoisomerization of dibenzobicyclo[2.2.2]octatrienes.

[Reaction: see text] Six chiral ionic liquids were prepared and evaluated as "chiral induction solvents" in which two different dibenzobicyclo[2.2.2]octatrienes were photoisomerized to chiral products. Enantiomeric excesses from 3 to 12% were obtained from the photochemical di-pi-methane rearrangement. Results indicate that the chiral induction derives from an ion pairing interaction of the deprotonated diacids with the ionic liquid cation. This is the first report on chiral induction via a chiral IL for an irreversible, unimolecular photochemical isomerization.

Alkenes↗
PubMed2005

Inhibition of gastric cancer angiogenesis by vector-based RNA interference for Raf-1.

Tumor angiogenesis plays an important role in the malignancy of solid tumors. A number of recent studies including our own have suggested that Raf-1 is involved in this process, and may be critical in regulating gene activation of several angiogenesis factors. To further define Raf-1 function in angiogenesis and to explore novel approaches to modulate angiogenesis, we employed the small interference RNA technique to knock-down gene expression of Raf-1 in gastric cancer cell line SGC7901 that expresses a high level of Raf-1. The protein level of Raf-1 in the SGC7901cells was decreased dramatically after transfection with a Raf-1 specific siRNA vector. Further study proved that, VEGF and HIF-1alpha, two angiogenesis promoting factors, were found to be downregulated. And we also find that Vector-based RNA interference for Raf-1 increases transfected gastric cell apoptosis and inhibits cellular proliferation. Our results suggest that Raf-1 may be involved in angiogenesis by controlling the expression of angiogenesis-related factors and provide a possible strategy for the treatment of tumor angiogenesis by targeting Raf-1.

Down-Regulation↗
PubMed2005

COX2-related multicentric mixed-type Castleman's disease in a young man.

BACKGROUND: A 34-year-old male presented with a 5-month history of fatigue, anorexia, low fever, night sweats, and oliguria with edema of the eyelid, exacerbated by abdominal distension and mild diarrhea of 3 weeks duration. Physical examination showed positive signs of ascites, palpable spleen, slight abdominal tenderness and mild rebound tenderness in the lower abdomen, and edema of the lower limbs. Initial laboratory tests revealed abnormal liver biochemistry and increased protein concentration in the urine. Chest X-ray showed minimal pleural effusion in both sides of the thoracic cavity, and ultrasound detected moderate ascites, several small lymph nodes in the retroperitoneum, and mild splenomegaly with widening of the splenic vein. A lymph node biopsy established the diagnosis, and cytokine analysis in the serum revealed COX2 as the possible mediator. INVESTIGATIONS: Abdominal paracentesis, chest X-ray, abdominal ultrasound, thoracic and abdominal CT scans, gastroscopy, colonoscopy, biopsies of the liver, bone marrow and lymph nodes, immunophenotype staining for lymphocytes, cytokine analysis. DIAGNOSIS: COX2-related multicentric mixed-type Castleman's disease. MANAGEMENT: Chemotherapy and COX2 inhibitors.

Adult↗
PubMed2005

Bird's-eye view on gastric cancer research of the past 25 years.

This paper provides a bird's-eye view of our 25-year research work on gastric cancer, including both exploration of pathogenesis and preclinical or clinical applications of diagnosis and treatment. Although there have been achievements and reasons for applause, there are, nonetheless, more failings and teachings. Some problems that we experienced 25 years ago are still problems we have to face today. We are absolutely not singing the same old tune. Looking back makes us wiser and our way smoother. Although it is a long and arduous way to further study gastric cancer, we are willing to devote ourselves to it.

Biomedical Research↗
PubMed2005

Detection of mutations in the COL4A5 gene by analyzing cDNA of skin fibroblasts.

BACKGROUND: Alport syndrome is a progressive hereditary glomerulonephritis that is characterized by hematuria, sensorineural deafness, ocular lesions, and progressive renal failure. The majority of cases (about 85%) are caused by mutations in the COL4A5 gene on the X chromosome which encodes the type IV collagen alpha5 chain (X-linked Alport syndrome). METHODS: In this study we performed a systematic analysis of the entire coding region of COL4A5 mRNA in 31 unrelated Chinese X-linked Alport syndrome patients and four controls by using reverse transcription-polymerase chain reaction (RT-PCR) and direct sequencing methods. The mRNA analyzed was isolated from cultured skin fibroblasts of Alport syndrome patients. RESULTS: The entire sequences of mRNA of the controls corresponded exactly to the published sequence. There were 28 variants detected by analyzing mRNA of COL4A5 in 28/31 patients. Of those, a total of 25 functionally significant COL4A5 mutations was confirmed in 25/31 patients by using RT-PCR method and subsequently confirmed at genomic DNA level, which included seven different mutations described in previous reports, and 18 novel mutations. The mutation detection rate was 80.6% (25/31), which is comparable with the highest previous detection sensitivity of COL4A5 mutations in evident X-linked Alport syndrome using genomic DNA. Furthermore, three splicing mutations that occurred at the cryptic splice sites and would be overlooked or simply considered as intronic sequence variations by solely analyzing genomic DNA were identified in this study. CONCLUSION: RT-PCR and direct sequencing using cultured skin fibroblasts RNA is a practical approach with high sensitivity for genetic analysis in X-linked Alport syndrome patients.

Chromosomes, Human, X↗
PubMed2005

[Apoptosis and expressions of PDCD5 and Caspase-3 in renal tissues of children with lupus nephritis].

OBJECTIVE: To improve the understanding of the pathogenesis of lupus nephritis (LN) by studying the relationship between apoptosis and proliferation in children with LN. METHODS: Thirty-one children (23 girls, 8 boys, aged 6-16 years) with biopsy-proven LN (21 type IV, 6 type V, 2 type II and 2 type III) and nine controls were included in the study. Apoptosis was detected by in situ nick-end labeling techniques (TUNEL) in renal biopsy samples. Proliferation was shown by PCNA detection. Immunohistochemistry was employed to detect the expressions of PCNA, PDCD5 and Caspase-3. The images of glomeruli (G) and renal tubuli (T) were selected randomly on each biopsy sample, respectively, and transferred into computer by SECOM video camera. The quantity of PDCD5 and Caspase-3 expressions were evaluated according to the average intensity of PDCD5 and Caspase-3. RESULTS: 1. Compared to control group, the patients with LN had increased apoptotic cells (G: 0.14 +/- 0.09 vs. 0.86 +/- 0.26; T: 0.16 +/- 0.07 vs. 1.16 +/- 0.42; P < 0.01) and increased PCNA positive cells (G: 0.47 +/- 0.25 vs. 8.45 +/- 2.83; T: 1.32 +/- 0.15 vs. 13.73 +/- 3.54; P < 0.01) in glomeruli and renal tubuli. The high ratios of PCNA/apoptosis (P/A) were observed in glomeruli (3.37 +/- 1.93 vs. 10.01 +/- 2.96, P < 0.01) and tubuli (8.94 +/- 1.79 vs. 12.81 +/- 3.91, P < 0.05) in LN group. 2. There was no difference in expression of PDCD5 in glomeruli between LN children and controls (0.09 +/- 0.05 vs. 0.08 +/- 0.02, P > 0.05). The expression of PDCD5 in renal tubuli decreased significantly in LN children compared with controls (0.13 +/- 0.05 vs. 0.21 +/- 0.07, P < 0.01). 3. The expression of Caspase-3 in children with LN increased significantly in glomeruli and tubuli compared with that in controls (0.22 +/- 0.07 vs. 0.05 +/- 0.02; 0.08 +/- 0.03 vs. 0.05 +/- 0.01; P < 0.01). 4. The number of glomerular apoptotic cells showed a positive correlation with the expression of Caspase-3 (r = 0.718, P < 0.01), but no correlation with the expression of PDCD5 in all cases (r = 0.054, P > 0.05). The intensity of PDCD5 expression in glomeruli and renal tubuli showed no correlation with that of Caspase-3 expression in all cases (r = 0.061, P > 0.05, r = 0.049, P > 0.05). Stepwise multiple regression revealed that the number of apoptotic cells in renal tubuli correlated negatively with the intensity of PDCD5 expression, whereas correlated positively with intensity of Caspase-3 expression in all cases. CONCLUSIONS: 1. Although the number of apoptotic cells in the kidney of LN was more than that in the kidney of control group, the apoptosis in the kidney of LN was relative insufficient compared with the proliferation. 2. Caspase-3 was involved in the apoptosis of glomeruli and renal tubuli of LN. 3. It was unclear if PDCD5 participated in the apoptosis of glomeruli of LN. While PDCD5 might participate the apoptosis of renal tubuli in LN.

Adolescent↗
PubMed2005

[NPHS1 mutations in a Chinese family with congenital nephrotic syndrome].

OBJECTIVE: Congenital nephrotic syndrome (CNS) is defined as heavy proteinuria or nephrotic syndrome occurring before 3 months of age. It is characterized by early onset, resistance to steroid therapy and progressing to end-stage renal disease (ESRD). In recent years, several genes associated with CNS have been identified, such as NPHS1, NPHS2 and WT1. The mutations of these genes have been identified in the patients with CNS in Finland, other European countries, North Africa, North America, and Asia, respectively. However, the investigation of the above genes has not been performed in Chinese CNS patients. In this study, NPHS1 mutations in a Chinese family with CNS were detected and analyzed. METHODS: There were two CNS patients in the investigated family. The proband, a 45-day-old boy, was born at fullterm and weighed 2700 g at birth. The placenta weighed 450 g. At the age of 10 days, generalized edema, proteinuria, hypoproteinemia, and hypoalbuminemia were found without renal insufficiency. The proband's sister, with the same phenotype and normal renal function, underwent renal biopsy at 5 years of age. Their parents and elder half-sister all had normal phenotypes. Genomic DNA samples were extracted from peripheral bloods of the proband, his family members and 50 unrelated, normal individuals. All 29 exons and exon-intron boundaries of NPHS1 were detected in the proband by polymerase chain reaction (PCR), direct DNA sequencing, and restriction enzyme analysis. RESULTS: Three heterozygous mutations of NPHS1, namely, G928A (D310N), 1893-1900del 8 (CGAAACCG), and G2869C (V957L) were identified in the proband. These mutations involved exons 8, 14, and 21. The same genotype was found in the proband's sister who had the same phenotype, but was not detected in proband's elder half-sister who had normal phenotype. Fifty normal individuals had no these mutations. The proband's mother with normal urinalysis had G928A (D310N) heterozygous mutation, and the father with normal urinalysis had two heterozygous mutations of 1893-1900del 8 (CGAAACCG) and G2869C (V957L). At the same time, three types of single nucleotide polymorphisms (SNPs), E117K (rs3814995), S1105S (rs2071327), and IVS27+45c > t, were confirmed in the proband. Another variant, IVS8+68 a > g had also been found. CONCLUSION: This is the first report about NPHS1 mutations in Chinese CNS kindred. These three heterozygous mutations of NPHS1 are novel genetic defects of CNS, which have not been described before.

Asian People↗
PubMed2004

Functional analysis of acidic amino acids in the cytosolic tail of the Na+/H+ exchanger.

The mammalian Na(+)/H(+) exchanger is a membrane protein with a C-terminal regulatory cytosolic domain and an N-terminal membrane domain. Na(+)/H(+) exchanger isoform 1 (NHE1) possesses a conserved amino acid sequence of seven consecutive acidic residues in the distal region of the cytosolic tail. We examined the structural and functional role of this acidic sequence. In human NHE1, varying mutations of the sequence (753)EEDEDDD(759) resulted in defective NHE1 activity. Mutation of the core acid sequence, (755)DED(757), or of the entire sequence caused a decrease in the activity of NHE1 in response to acute acid load. This was not due to changes in Na(+) affinity but rather due to decreased maximum velocity of the protein and delayed activation. Mutation of the target sequence did not affect the ability of the cytoplasmic domain to bind carbonic anhydrase II or tescalcin but did affect calmodulin binding. Mutation of the acidic domain also caused altered sensitivity to trypsin and changes in size of the protein in gel-filtration chromatography and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Our results demonstrate that the acidic sequence is critical in maintaining proper conformation of the cytosolic domain, calmodulin binding, and in maintenance of Na(+)/H(+) exchanger activity.

Amino Acid Sequence↗