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Biomedical subjects

J Peng

Publications and source records attributed to J Peng.

At least 73 records · Page 4Linked to original sources
PubMed2000

Molecular cloning of canine bullous pemphigoid antigen 2 cDNA and immunomapping of NC16A domain by canine bullous pemphigoid autoantibodies.

The autoantibody-mediated subepidermal blistering skin disease bullous pemphigoid affects both humans and dogs. We previously demonstrated that canine bullous pemphigoid patient's autoantibodies targeted skin basement membrane component and a 180-kDa keratinocyte protein. We extend our works to partially isolate the cDNA encoding canine bullous pemphigoid antigen 2 (BPAg2, BP180). Total RNA extracted from a papillomavirus-immortalized canine keratinocyte cell line and a cultured canine squamous carcinoma cell line SCC 2/88 were used to isolate fragments of cDNA encoding BPAg2 by reverse transcription-PCR and 5'-rapid amplification of cDNA end. The isolated sequence included the 5'-untranslated region, the entire intracellular, transmembranous, and extracellular NC16A autoantigenic domains, plus a small segment of the collagenous domain. Sequence analyses of the isolated cDNA showed 87 and 85% identities between canine and human at the nucleotide sequence and at the deduced amino acid sequence levels, respectively. The canine BPAg2 sequence was confirmed by a rabbit antibody raised against a 18-amino acid peptide deduced from the canine NC16A nucleotide sequence. Autoantibodies from canine bullous pemphigoid patients' sera recognized epitopes within the human NC16A domain. The cloning of the cDNA encoding this disease-associated protein may allow us to develop a canine model in dissecting the immunopathologic mechanism underlying bullous pemphigoid.

Animals↗
PubMed2000

Plant GRAS and metazoan STATs: one family?

GRAS is a recently discovered family of plant-specific proteins that play important regulatory roles in diverse aspects of plant development. Several of the motifs present in the GRAS proteins suggest that they function as transcription factors, although homology-searching programs have revealed no significant similarity to any non-plant proteins. Here we propose that the GRAS proteins are related to the Signal Transducers and Activators of Transcription (STAT) family of proteins. STATs are known in many non-plant species, and act as intracellular intermediaries between extracellular ligands and the transcription and activation of genes. Our hypothesis is that the GRAS proteins perform this function in plants, with mechanisms similar to those of the animal STATs. If true, this hypothesis has important implications for the evolution of phosphotyrosine based signal transduction systems in eukaryotic organisms. BioEssays 22:573-577, 2000.

Amino Acid Sequence↗
PubMed2000

NUDEL is a novel Cdk5 substrate that associates with LIS1 and cytoplasmic dynein.

Disruption of one allele of the LIS1 gene causes a severe developmental brain abnormality, type I lissencephaly. In Aspergillus nidulans, the LIS1 homolog, NUDF, and cytoplasmic dynein are genetically linked and regulate nuclear movements during hyphal growth. Recently, we demonstrated that mammalian LIS1 regulates dynein functions. Here we characterize NUDEL, a novel LIS1-interacting protein with sequence homology to gene products also implicated in nuclear distribution in fungi. Like LIS1, NUDEL is robustly expressed in brain, enriched at centrosomes and neuronal growth cones, and interacts with cytoplasmic dynein. Furthermore, NUDEL is a substrate of Cdk5, a kinase known to be critical during neuronal migration. Inhibition of Cdk5 modifies NUDEL distribution in neurons and affects neuritic morphology. Our findings point to cross-talk between two prominent pathways that regulate neuronal migration.

1-Alkyl-2-acetylglycerophosphocholine Esterase↗
PubMed2000

Microsatellite diversity correlated with ecological-edaphic and genetic factors in three microsites of wild emmer wheat in North Israel.

This study was conducted to test the effects of internal (genetic) and external factors on allelic diversity at 27 dinucleotide microsatellite (simple sequence repeat [SSR]) loci in three Israeli natural populations of Triticum dicoccoides from Ammiad, Tabigha, and Yehudiyya, north of the Sea of Galilee. The results demonstrated that SSR diversity is correlated with the interaction of ecological and genetic factors. Genetic factors, including genome (A vs. B), chromosome, motif, and locus, affected average repeat number (ARN), variance in repeat number (sigma), and number of alleles (NA) of SSRs, but the significance of some factors varied among populations. Genome effect on SSR variation may result from different motif types, particularly compound (or imperfect) versus perfect motifs, which may be related to different evolutionary histories of genomes A and B. Ecological factors significantly affected SSR variation. Soil-unique and soil-specific alleles were found in two edaphic groups dwelling on terra rossa and basalt soils across macro- and microgeographical scales. The largest contributions of genetic and ecological effects were found for diversity of ARN and NA, respectively. Multiple regression indicated that replication slippage and unequal crossing over could be important mutational mechanisms, but their significance varied among motifs. Edaphic stresses may affect the probability of replication errors and recombination intermediates and thus control diversity level and divergence of SSRs. The results may indicate that SSR diversity is adaptive, channeled by natural selection and influenced by both internal and external factors and their interactions.

Dinucleotide Repeats↗
PubMed2000

Molecular genetic maps in wild emmer wheat, Triticum dicoccoides: genome-wide coverage, massive negative interference, and putative quasi-linkage.

The main objectives of the study reported here were to construct a molecular map of wild emmer wheat, Triticum dicoccoides, to characterize the marker-related anatomy of the genome, and to evaluate segregation and recombination patterns upon crossing T. dicoccoides with its domesticated descendant Triticum durum (cultivar Langdon). The total map length exceeded 3000 cM and possibly covered the entire tetraploid genome (AABB). Clusters of molecular markers were observed on most of the 14 chromosomes. AFLP (amplified fragment length polymorphism) markers manifested a random distribution among homologous groups, but not among genomes and chromosomes. Genetic differentiation between T. dicoccoides and T. durum was attributed mainly to the B genome as revealed by AFLP markers. The segregation-distorted markers were mainly clustered on 4A, 5A, and 5B chromosomes. Homeoalleles, differentially conferring the vigor of gametes, might be responsible for the distortion on 5A and 5B chromosomes. Quasilinkage, deviation from free recombination between markers of nonhomologous chromosomes, was discovered. Massive negative interference was observed in most of the chromosomes (an excess of double crossovers in adjacent intervals relative to the expected rates on the assumption of no interference). The general pattern of distribution of islands of negative interference included near-centromeric location, spanning the centromere, and median/subterminal location. [An appendix describing the molecular marker loci is available as an online supplement at http://www.genome.org.]

Binomial Distribution↗
PubMed2000

Tat modifies the activity of CDK9 to phosphorylate serine 5 of the RNA polymerase II carboxyl-terminal domain during human immunodeficiency virus type 1 transcription.

Tat stimulates human immunodeficiency virus type 1 (HIV-1) transcriptional elongation by recruitment of carboxyl-terminal domain (CTD) kinases to the HIV-1 promoter. Using an immobilized DNA template assay, we have analyzed the effect of Tat on kinase activity during the initiation and elongation phases of HIV-1 transcription. Our results demonstrate that cyclin-dependent kinase 7 (CDK7) (TFIIH) and CDK9 (P-TEFb) both associate with the HIV-1 preinitiation complex. Hyperphosphorylation of the RNA polymerase II (RNAP II) CTD in the HIV-1 preinitiation complex, in the absence of Tat, takes place at CTD serine 2 and serine 5. Analysis of preinitiation complexes formed in immunodepleted extracts suggests that CDK9 phosphorylates serine 2, while CDK7 phosphorylates serine 5. Remarkably, in the presence of Tat, the substrate specificity of CDK9 is altered, such that the kinase phosphorylates both serine 2 and serine 5. Tat-induced CTD phosphorylation by CDK9 is strongly inhibited by low concentrations of 5, 6-dichloro-1-beta-D-ribofuranosylbenzimidazole, an inhibitor of transcription elongation by RNAP II. Analysis of stalled transcription elongation complexes demonstrates that CDK7 is released from the transcription complex between positions +14 and +36, prior to the synthesis of transactivation response (TAR) RNA. In contrast, CDK9 stays associated with the complex through +79. Analysis of CTD phosphorylation indicates a biphasic modification pattern, one in the preinitiation complex and the other between +36 and +79. The second phase of CTD phosphorylation is Tat-dependent and TAR-dependent. These studies suggest that the ability of Tat to increase transcriptional elongation may be due to its ability to modify the substrate specificity of the CDK9 complex.

Biotin↗
PubMed2000

Saponins isolated from Allium chinense G. Don and antitumor-promoting activities of isoliquiritigenin and laxogenin from the same drug.

Investigation of the Chinese crude drug "Xiebai," the bulbs of Allium chinense G. Don (Liliaceae), led to the isolation of 2 saponins, xiebai-saponin I (laxogenin 3-O-beta-xylopyranosyl (1-->4)-[alpha-arabinopyranosyl (1-->6)-beta-glucopyranoside) (1) and laxogenin 3-O-alpha-arabinopyranosyl (1-->6)-beta-glucopyranoside (2), and the aglycone, laxogenin (3), together with 2 chalcones, isoliquiritigenin (4) and isoliquiritigenin-4-O-glucoside (5), and beta-sitosterol glucoside (6). Compounds 1-5 were tested in vitro for their inhibitory effect on the 12-O-tetradecanoylphorbol-13-acetate (TPA)-stimulated 32Pi-incorporation into phospholipids of HeLa cells. In addition to this, laxogenin (3) was proven to have an antitumor-promoting activity in a two-stage lung carcinogenesis experiment.

Allium↗
PubMed2000

The mutation of insulin receptor substrate-1 gene in Chinese patients with non-insulin-dependent diabetes mellitus.

OBJECTIVE: To identify the relationship between mutation in the insulin receptor substrate-1 (IRS-1) gene and the incidence of non-insulin-dependent diabetes mellitus (NIDDM) in the Chinese population. METHODS: Samples were obtained from 68 Chinese patients with NIDDM and 68 control subjects. The +1700-(+)4437 bp fragment of the IRS-1 gene was screened by polymerase chain reaction (PCR)-single strand conformation polymorphism (SSCP) analysis. All SSCP variations were submitted to DNA sequence analysis. RESULTS: Two amino acid variations [GGG-->AGG (G971 R) and CCT-->TCT (P1079 S)] and 3 silent mutations [GAT-->GAC(D422D), CCA-->CCC(P737 P) and GCA-->GCG (A804 A)] were identified, among which the CCA-->CCC(P737 P) and CCT-->TCT(P1079S) have not been previously reported. All five variations were found in Chinese patients with NIDDM, while GCA-->GCG(A804A) was the only one found in control subjects. The overall incidence of the five variations in Chinese patients with NIDDM were much higher than that in control subjects (38.2% vs 7.4%, chi 2 = 18.42, P < 0.01). The most common polymorphism in the Chinese population was GCA-->GCG (A804A), and its frequency was significantly higher in Chinese patients with NIDDM than in controls (26.5% vs 7.4%, chi 2 = 8.84, P < 0.01). The homozygotes of the variation in patients with NIDDM and control subjects were 8.8% and 1.5%, respectively (chi 2 = 2.41, P > 0.05). CONCLUSION: These results indicate that there may be a relation between these nucleotide variations of IRS-1 gene and Chinese patients with NIDDM.

Adult↗
PubMed2000

[Descriptive epidemiology of upper aerodigestive tract cancers in the department of Somme].

The aim of this study is to show the epidemiologic features of upper aerodigestive tract cancers in the department of Somme. This study focused on the 1984-1995 period. For men, the upper aerodigestive tract cancers are the most frequent cancers in the Somme area. The incidence rate of pharynx cancers has shown slightly a decline over the past 10 years. The mortality rate of larynx cancers for males fell from 18.2 in 1984-1987 to 13.8 in 1992-1995 per 100,000. 5-year survival rates are between 20 and 39% for men, and from 23 to 42% for women. France has the highest incidence of these cancers in Europe. Within the country, the Somme area has a high risk for incidences and mortality as well. The results of this study indicate that upper aerodigestive tract cancers represent a serious problem for public health. Further areas need to be researched before such factors can be causally implicated in the aetiology of the disease in order to make up the prevention.

Adult↗
PubMed2000

Anti-HBV effect of targeted antisense RNA against HBV C gene.

OBJECTIVE: To investigate the anti-HBV effect of targeted antisense RNA to hepatic cells. METHODS: pREP4-aC which would transcript antisense RNA against HBV C gene in eukaryotic cells were delivered into 2.2.15 cells by glactosylated poly-L-lisine (Gal-PLL), and the positive cells were selected. HBsAg, HBeAg and HBV DNA produced by 2. 2.15 cells were detected with ELISA or Southern blot during the experiment, and the cytotoxicity of targeted antisense on 2.2.15 cells was observed. RESULTS: The inhibition effect on HBsAg, HBeAg and HBV DNA occurred at the 24th hour after delivery and reached the highest level at the 6th day, and kept at lest two months. No cytotoxicity on 2.2.15 cells was observed. CONCLUSION: The targeted antisense against HBV C gene by delivery of Gal-PLL could effectively inhibit the antigen expression of HBV and DNA replication.

Antiviral Agents↗
PubMed2000

Correlation between bone mineral density and sexual hormones in healthy Chinese women.

Osteoporosis is a common disease in women, but not in men. It is usually induced by the deficiency of estrogen after menopause. The lumbar spine is most often affected. We examined 74 healthy Chinese women in whom we measured serum estradiol (E2), estriol (E3), and total testosterone (TTT) by radioimmunoassay (RIA). The bone mineral density (BMD) of the total lumbar spine in the anterior (TLS-A) and lateral (TLS-L) position, the region of interest (ROI) of lateral spine (M-IALS), the forearm, and the total hip (TH) were scanned by a dual-energy X-ray absorptiometer. We found that (1) E2 and all BMD determinations declined significantly after menopause (p < 0.05 for all), except the BMD of TH; (2) the BMD of TLS-L, TH, and forearm correlated significantly with E2 (r = 0.2986, p < 0.05), E3 (r = 0.3380, p < 0.05), and TTT (r = 0.2867, p < 0.05), respectively, by partial correlation analysis. In conclusion, BMD at different sites of the skeleton correlated with the level of different sex hormones. It seems that BMD at different sites of the body is controlled by different sex hormones. Whether this phenomenon should be considered in the choice of hormone replacement therapy, or in improving the BMD diagnostic standard, needs further study.

Adult↗
PubMed2000

[Seed rain and seed bank of constructive species in evergreen broadleaved forest at Chongqing Simian Mountain].

The study shows that the early and late seed rains of constructive tree species in evergreen broadleaved forest at Chongqing Simian Mountain had no activity. The bigger the seeds of the species and the earlier or later the seeds of the species matured, the higher the proportion of the seed rain damaged by animals. The quantitative variation of seed rain, active seed rain and seed bank did not take place at the same time. At early time, the number of seed banks of Castanopsis fargesii, Lithocarpus glabra, Quercus myrsinrefolia, Castanopsis plasyacantha, Cinamomum subavenium which own more active seed rain increased by geomitric series. The seed banks of Castanopsis orthacantha and Schima argentea were small, only survived a short time, and did not sprout next year. The quantitative dynamics of seed banks and their increasing or decreasing rates were decided by the proportion damaged by animals, dying speed of seeds and their resistance to pathogens and adverse circumstances, and the state of seed germination.

Biological Specimen Banks↗
PubMed2000

Expression of the MAGE-1 gene in human hepatocellular carcinomas.

OBJECTIVE: To further investigate the expression of MAGE-1 gene in hepatocellular carcinoma (HCC). METHODS: The tumors and adjacent liver tissue from 45 HCC patients and liver tissue from 28 non-HCC patients (16 with liver cirrhosis and 12 with normal liver) were characterized by RT-PCR. A 421 bp PCR product from a cDNA fragment spanning exons 1, 2 and 3 was sequenced. The HLA type was assayed by standard ELISA in 43 HCC patients. RESULTS: Thirty-two of 45 tumor tissues from HCC patients expressed MAGE-1 mRNA (71.1%). In contrast, MAGE-1 mRNA was not detected in adjacent tissues. Three were found to have point mutations at 3 identical sites resulting in the substitution of two amino acid residues. The most frequent HLA types in 43 HCC patients were: HLA-A2, 53.5%; A11, 25.6%; A24, 20.9%; A33, 20.9%; HLA-B13, 28.3% and B35, 23.2%. Expression of HLA-A33 (20.9%) was higher in HCC patients than that predicted in the normal Chinese population (8.8%). There was no discemable correlation between MAGE-1 expression and alpha-FP level, tumor size and hepatitis B or C virus infection. The identification of peptides which are restricted by haploptypes other than A1 should increase the opportunity for peptide based immunotherapy. CONCLUSIONS: This study shows that MAGE-1 mRNA is highly expressed in HCC tumor tissue in Chinese patients. Previously unreported point mutations in the MAGE-1 gene are described and may also provide additional opportunities for immunotherapy.

Amino Acid Sequence↗
PubMed2000

[Construction of a hepatoma-targeting vector of adeno-associated virus containing human alpha-fetoprotein promoter and wild p53 gene in gene therapy of liver cancer].

OBJECTIVE: To construct plasmids that express target genes in hepatoma cell line using adeno-associated virus (AAV) vectors containing human AFP promoter. METHODS: Primers containing specific enzyme-cutting sites were designed to amplify the alpha-fetoprotein promoter (AFP promoter) from human genome. The promoter was cloned into pTR-UF5, a plasmid containing GFP reporter gene, resulting in the recombinant AAV plasmid containing the reporter gene (rAAV-AFP-GFP). Blunted ligation was used to construct the recombinant AAV vector plasmid containing human wild p53 gene (rAAV-AFP-53). The plasmid rAAV-AFP-GFP was used to transfect the AFP-expressing Hep G(2) and non-AFP-expressing 293 cell lines, respectively, to measure the function of the cloned AFP promoter. Flow cytometry was used to measure the effect of rAAV-AFP-53 on hepatoma cell line HLE. RESULTS: rAAV-AFP-53 and rAAV-AFP-GFP were verified by DNA sequencing and enzyme digestion to carry human AFP promoter. Cell transfection of rAAV-AFP-GFP showed selective expression in AFP-positive hepatoma cell lines with a transfection rate of 36.5%; rAAV-AFP-53 induced apoptosis rate was 73.88%. CONCLUSION: Two adeno-associated virus plasmids are successfully constructed that carry p53 gene and reporter gene, respectively, guided by AFP promoter. The former one shows a hepatoma-specific apoptosis-inducing effect.

Apoptosis↗
PubMed2000

[The role of nitric oxide in the pathogenesis of portal hypertension].

OBJECTIVE: To investigate the role of nitric oxide in the pathogenesis of portal hypertension. METHODS: We measured the portal venous pressure of 75 patients via a catheter and detected the levels of plasma endotoxin and NO(2)(-)/NO(3)(-). RESULTS: The mean levels of plasma endotoxin and NO(2)(-)/NO(3)(-) (0.249 +/- 0.112 Eu/ml and 55.9 +/- 26.2 micromol/L) in portal hypertensive patients were significantly higher than those in the controls, and the highest values were observed in the portal venous blood. The mean portal venous pressure of the portal hypertensive patients was 35.5 +/- 4.4 cm H(2)O and was positively correlated with the levels of NO(2)(-)/NO(3)(-) (n = 25, r = 0.55, P < 0.01). Positive correlation existed between them during the postoperative period (r = 0.57, P < 0.05). There was a negative correlation between the levels of albumin and NO(2)(-)/NO(3)(-) (n = 75, r = -0.35, P < 0.01), and the mean levels of NO(2)(-)/NO(3)(-) were 72.4 +/- 20.3 micromol/L in the patients with ascites, much higher than those (50.3 +/- 21.0 micromol/L) without ascites. CONCLUSIONS: The levels of plasma endotoxin and nitric oxide were elevated in patients with portal hypertension, and NO might play an important role in the abnormal elevation of portal venous pressure and the damage to liver function.

Endotoxins↗
PubMed2000

[Surgery for lung cancer complicated by bronchial asthma].

OBJECTIVE: To assess surgery for lung cancer complicated by bronchial asthma. METHODS: Lung hilum denervation was performed for asthma during radical resection of lung cancer. One patient with peripheral bronchogenic carcinoma in the right upper lobe underwent upper lobectomy and extensive dissection of lymph-nodes. Simultaneously, lung hilum denervation was done by complete amputation of the sympathetic and parasympathetic nerves around the lung hilum. Another patient with central bronchogenic carcinoma in the left upper lobe underwent lung autotransplantation. Pneumonectomy was performed, and the tumor parts of the lung were resected subsequently and the preservable parts of the lung were replanted into the bed of the upper lobe. RESULTS: Follow-up showed that the two patients had been alive with tumor free for 80 months and 17 months respectively and the time of postoperative mechanical ventilation was 4 and 18 hours. The frequency of asthma paroxysm decreased and the severity attenuated. Parameters of blood gas and lung function were improved. CONCLUSIONS: The poor lung function caused by asthma should not be regarded as a contradiction for the removal of lung cancer. Complete denervation around the lung hilum during the radical resection of lung cancer may contribute to the better treatment of lung cancer and asthma.

Aged↗
PubMed2000

[Surgical treatment of single level unstable degeneration with foraminal stenosis].

OBJECTIVES: Lumbar spine single level unstable degeneration with foraminal stenosis was treated with unilateral decompression, disc excision, posterolateral interbody fusion utilizing single BAK cage and count-lateral facet joint screw fixation. The short-term and mid-term clinical results were evaluated. METHODS: There were thirty patients (13 male, 17 female) with an average age of 46.5 years. From posterior approach, all patients underwent unilateral decompression, disc excision, interbody fusion with posterolateral inserted single BAK cage, and count-lateral facet joint screw fixation. RESULTS: All patients underwent surgery safely without severe complications occurred such as infection and neurological damages. The average follow-up time was 12 months (6 - 18 months) with complete relief of symptoms. Solid fusion was achieved in all but 2 patients at final follow-up. 90% of the patients obtained successful clinical outcome. CONCLUSIONS: Complete decompression of the neural foramen can relief the symptoms, and interbody fusion utilizing threaded cage can restore the height of disc space and withstand axial loading of the spine. Addition of the facet joint fixation increased the postoperative segment stability and enhances solid fusion. With less invasive and preservation of part of the posterior elements of the lumbar spine and the solid fusion achieved, we consider it a sound procedure for the treatment of single level unstable degeneration with foraminal stenosis of lumbar spine. Long-term follow-up results needs to be observed.

Adult↗