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Jun Cheng

Publications and source records attributed to Jun Cheng.

At least 127 records · Page 7Linked to original sources
PubMed2002

Precancerous foci in pleomorphic adenoma of the salivary gland: recognition of focal carcinoma and atypical tumor cells by P53 immunohistochemistry.

BACKGROUND: It is still controversial if atypical tumor cells scattered in salivary pleomorphic adenomas are precancerous and how carcinoma arises in pleomorphic adenomas. METHODS: We studied clinicopathologically the frequency and variation of cellular atypia among tumor cells and examined the expression status of p53 gene products as well as proliferating cell nuclear antigen (PCNA) in 101 surgical materials of pleomorphic adenomas. RESULTS: Histopathologically, atypical tumor cells were found in 51% of the cases examined. Their mode of distribution was classified into three groups: focal (six cases, 6%) which could be identified as focal carcinoma, measuring less than 1 mm in diameter; sporadic (15 cases, 15%) and singular (30 cases, 30%). These atypical cells were located mainly within sheet-like nests of tumor cells but not in chondroid or fibro-hyaline foci. Immunohistochemically, most of the atypical cells were positive for p53 gene products and PCNA. CONCLUSION: The results indicated that atypical cells with p53 protein accumulation in their nuclei could be regarded as cells in a precancerous state not yet forming an apparent carcinomatous nest. Some cell population with these atypical cells are likely to form focal carcinomas and then to an apparent form of carcinoma in pleomorphic adenoma.

Adenocarcinoma↗
PubMed2002

Sebaceous lymphadenoma of the lip: report of a case of minor salivary gland origin.

A case of sebaceous lymphadenoma occurring in the lip of a 73-year-old female is described. The patient had noticed a painless mass in the region of her upper lip for a year. The surgically removed tumor, measuring about 10 mm in diameter, was located just beneath the lip mucosa, expanding into the submucosal and muscle layer. Histologically, the tumor was well encapsulated and consisted of scattered round-shaped islands of small squamous epithelial cells with focal but apparent sebaceous differentiation in a background of lymphoid stroma. This is the first case report of sebaceous lymphadenoma of minor salivary gland origin.

Aged↗
PubMed2002

Ascorbic-acid transporter Slc23a1 is essential for vitamin C transport into the brain and for perinatal survival.

The only proven requirement for ascorbic acid (vitamin C) is in preventing scurvy, presumably because it is a cofactor for hydroxylases required for post-translational modifications that stabilize collagen. We have created mice deficient in the mouse ortholog (solute carrier family 23 member 1 or Slc23a1) of a rat ascorbic-acid transporter, Svct2 (ref. 4). Cultured embryonic fibroblasts from homozygous Slc23a1(-/-) mice had less than 5% of normal ascorbic-acid uptake. Ascorbic-acid levels were undetectable or markedly reduced in the blood and tissues of Slc23a1(-/-) mice. Prenatal supplementation of pregnant females did not elevate blood ascorbic acid in Slc23a1(-/-) fetuses, suggesting Slc23a1 is important in placental ascorbic-acid transport. Slc23a1(-/-) mice died within a few minutes of birth with respiratory failure and intraparenchymal brain hemorrhage. Lungs showed no postnatal expansion but had normal surfactant protein B levels. Brain hemorrhage was unlikely to be simply a form of scurvy since Slc23a1(-/-) mice showed no hemorrhage in any other tissues and their skin had normal skin 4-hydroxyproline levels despite low ascorbic-acid content. We conclude that Slc23a1 is required for transport of ascorbic acid into many tissues and across the placenta. Deficiency of the transporter is lethal in newborn mice, thereby revealing a previously unrecognized requirement for ascorbic acid in the perinatal period.

Animals↗
PubMed2002

Regulation of transient outward current in human atrial myocytes by protein tyrosine kinase pathway.

INTRODUCTION: Regulation of transient outward current (I(to)) in human myocytes is unclear. The present study investigated the effect of protein tyrosine kinase (PTK) inhibitors on I(to) in human atrial myocytes. METHODS AND RESULTS: Atrial myocytes were isolated enzymatically from biopsies of human right atrial appendage obtained from patients undergoing coronary artery bypass surgery. I(to) was recorded by the whole-cell patch-clamp technique in voltage-clamp configuration. Two groups of PTK inhibitors, the ATP binding site PTK inhibitors genistein and AG957 and the protein substrate PTK inhibitors ST638 and PP2, significantly inhibited I(to) in a concentration-dependent manner, with a potency order of genistein>AG957>ST638>PP2. At test pulse potential of +60 mV, I(to) was inhibited by 28% +/- 3%, 59% +/- 3%, and 89% +/- 3% by 15, 50, and 100 microM genistein, respectively. Daidzein and PP3, inactive analogues of genistein and PP2, respectively, did not produce any inhibitory effects on I(to). In addition to the inhibition of I(to) amplitude, the protein substrate PTK inhibitors ST638 and PP2 significantly accelerated I(to) inactivation (current decay) and delayed recovery from inactivation. Inhibition of protein tyrosine phosphatase partially reversed the effect of genistein. Stimulation or inhibition of serine/ threonine kinases (PKA, PKC, and PKG) did not change I(to) or alter the inhibitory response of PTK inhibitors on I(to). CONCLUSION: In human atrial cells, the PTK pathway plays an important role in the regulation of basal I(to), independent of serine/threonine kinases.

Aged↗
PubMed2002

Castleman's disease of the buccal mucosa: report of a case and review of the literature of head and neck cases.

A case of Castleman's disease occurring in the buccal mucosa is described. An 84-year-old woman noticed that a mass in the left buccal mucosa that had been present for half a year. Computed tomography revealed a well-demarcated submucosal tumor, measuring 4.0 x 3.0 x 2.0 cm. The patient received no treatment at this time, and continued growth of the mass was observed. After incisional biopsy, the lesion was surgically removed. Histologically, the tumor consisted of an enlarged lymph node with conspicuous lymph follicles, in which vascular channels and deposits of eosinophilic material were noted. Laboratory examination showed an increase of serum antibody level of cytomegalovirus but of no other viruses. The patient was followed up for 1(1/2) years, with no clinical evidence of recurrence. This is the first report of Castleman's disease presenting in an oral site.

Aged↗
PubMed2002

Audiometric findings in workers exposed to low levels of styrene and noise.

Audiometry and exposure measurements were conducted on workers from fiberglass and metal products manufacturing plants and a mail distribution terminal (N = 313). Workers exposed to noise and styrene had significantly worse pure-tone thresholds at 2, 3, 4, and 6 kHz when compared with noise-exposed or nonexposed workers. Age, noise exposure, and urinary mandelic acid (a biologic marker for styrene) were the variables that met the significance level criterion in the multiple logistic regression. The odds ratios for hearing loss were 1.19 for each increment of 1 year of age (95% confidence interval [CI], 1.11-1.28), 1.18 for every decibel >85 dB(A) of noise exposure (95% CI, 1.01-1.34), and 2.44 for each millimole of mandelic acid per gram of creatinine in urine (95% CI, 1.01-5.89). Our findings suggest that exposure to styrene even below recommended values had a toxic effect on the auditory system.

Adult↗
PubMed2002

Preparation of human single chain Fv antibody against hepatitis C virus E2 protein and its identification in immunohistochemistry.

AIM: To screen human single chain Fv antibody (scFv) against hepatitis C virus E2 antigen and identify its application in immunohistochemistry. METHODS: The phage antibody library was panned by HCV E2 antigen, which was coated in microtiter plate. After five rounds of biopanning,56 phage clones were identified specific to HCV E2 antigen. The selected scFv clones were digested by SfiI/NotI and DNA was sequenced. Then it was subcloned into the vector pCANTAB5E for expression as E-tagged soluble scFv. The liver tissue sections from normal person and patients with chronic hepatitis B and chronic hepatitis C were immunostained with HCV E2 scFv antibody. RESULTS: The data of scFv-E2 DNA digestion and DNA sequencing showed that the scFv gene is composed of 750 bp. ELISA and immunohistochemistry demonstrated that the human single chain Fv antibody against hepatitis C E2 antigen has a specific binding character with hepatitis virus E2 antigen and paraffin-embedded tissue, but did not react with liver tissues from healthy persons or patients with chronic hepatitis B. CONCLUSION: We have successfully screened and identified HCV E2 scFv and the scFv could be used in the immunostaining of liver tissue sections from patients with chronic hepatitis C.

Amino Acid Sequence↗
PubMed2002

[Construction and expression of humanized anti-HBsAg scFv targeting interferon-alpha in escherichia coli].

OBJECTIVE: To develop a bacteria expression system to produce the fusion protein of humanized anti-HBsAg scFV and interferon-alpha. METHODS: The expression vector was constructed after cleaving the plasmids harboring the humanized anti-HBsAg scFv and interferon alpha respectively and ligating to linearized pET22b subsequence. The expression of fusion protein in E.coli was analyzed by SDS-PAGE. The binding activity and antiviral activity of the fusion protein was characterized by competing inhibition test and cytopathic effect reduction. RESULTS: The plasmid harboring the in frame arranged fusion gene was constructed and identified. After induction for 12h, a new band close to 4.5 10(4) was observed using SDS-PAGE. Results of competing ELISA and cytopathic effect reduction showed the fusion protein retained its specific binding activity and antiviral activities. CONCLUSIONS: The construction and expression of the fusion gene of humanized anti-HBsAg scFv and interferon in E.coli are successful.

Electrophoresis, Polyacrylamide Gel↗
PubMed2002

[Preparation of human single chain Fv antibody specifically against hepatitis C virus E2 antigen].

OBJECTIVE: To identify human single chain Fv antibody (ScFv) against hepatitis C viral E2 antigen and its value clinically. METHODS: The recombinant phages were panned by E2 antigen which was coated in a microtiter plate. After five rounds of biopanning, 56 phage clones were identified specific to E2 antigen. The affinity and specificity of ScFv were evaluated by ELISA and immunohistochemistry, respectively. RESULTS: The data of E2-ScFv DNA digestion and DNA sequencing showed that the ScFv gene was composed of 750bp. ELISA and immunohistochemistry demonstrated that the human single chain Fv antibody against HCV E2 antigen had a specific combination character with hepatitis C virus E2 antigen. CONCLUSIONS: ScFv, having a sutestantial affinity and specificity and being easy to prepare, is valuable in the detection of HCV E2 antigen.

Amino Acid Sequence↗
PubMed2002

[Inducible expression of non-structural protein 3 of hepatitis C virus in E. coli].

BACKGROUND: To express recombinant non-structural protein 3 of hepatitis C virus (HCV) in E. coli. METHODS: The non-structural 3 (NS3) region DNA fragment of HCV was amplified by polymerase chain reaction (PCR) and inserted into inducible proeukaryotic expressive vector pET 30C(+)at Bam H1/EcoR1 sites. The competent BL21 (DE3) E.coli was transformed, and then cultured and induced with IPTG. The expressed HCV NS3 protein was confirmed with ELISA and dot blot hybridization using HCV NS3-specific single chain Fv (ScFv) antibody. RESULTS: 1 893 bp DNA fragment of HCV NS3 coding region was amplified by PCR technique. HCV NS3 expressive vector pET-NS3 was constructed. After transformation with pET-NS3 and induction with IPTG, recombinant HCV NS3 protein was expressed and confirmed by specific ELISA and dot blot hybridization. CONCLUSIONS: The recombinant HCV NS3 can be expressed in E. coli.

Escherichia coli↗
PubMed2002

[A preliminary study on the heterogeneity of preS2 region in hepatitis B virus].

OBJECTIVE: To investigate the mutation of the preS2 gene sequence of HBV and clarify the significance of HBV quasispecies groups in the patients with chronic HBV infection. METHODS: A set of specific primers were synthesized according to HBV DNA sequence of a Chinese strain. The preS2 gene region was amplified by PCR method from the sera of 51 patients with chronic HBV infection, and the PCR products from 5 patients were subcloned into pGEM Teasy vectors. Polyacrylamide gel electrophoresis (PAGE) was employed to display the deletion mutations, clones with differential length were selected and sequenced. Sequence comparison was made to find the difference. RESULTS: When analyzed by PAGE, 2 approximately 3 bands were displayed in the PCR products from 52.9% (27/51) patients. This phenomena of multiple bands in PAGE was detected in both HBeAg (36.1%) and anti-HBe (93.3%) positive patients, the difference between the 2 groups being statistically significant (P < 0.01). Analysis on deduced amino acid sequence showed the deletion mutations were in the N-terminal half of the preS2-encoded protein. CONCLUSION: There is a hot deletion region in preS2 gene sequence. These deletion mutations were more frequently found in patients with both anti-HBe and HBV DNA positivity. The deletion may influence the recognition by neutralizing antibodies. Our results suggest that there are HBV quasispecies in patients with chronic HBV infection.

Gene Deletion↗
PubMed2002

[Epitope mapping of hepatitis C virus non-structure protein 5 from a 7 peptide phage library by using immobilized specific monoclonal antibody].

OBJECTIVE: To screen HCV NS5 mimotopes by using monoclonal antibody and phage peptide library. METHODS: By using HCV NS5 monoclonal antibody as selective molecule, a 7 peptide phage library was biopanned and positive clones were selected by ELISA, competition assay and DNA sequencing. RESULTS: Twelve positive clones were chosen for DNA sequencing. From the experiment and sequencing comparison results, one epitope was confirmed as the mimotope of HCV NS5. CONCLUSIONS: HCV mimotope is obtained by phage peptide library screening. The result provides a new approach for HCV therapy and vaccine development.

Amino Acid Sequence↗
PubMed2002

[Synergetic transactivating functions of HCV core and truncated HBV middle surface protein].

OBJECTIVE: To investigate the synergetic transactivating functions of HCV core and truncated HBV middle surface proteins. METHODS: Two recombinant expression plasmids harboring HCV core and C-terminally truncated HBV middle surface protein gene were constructed, respectively. The plasmids were transfected into HepG2 cells and cotransfected HepG2 cells with reporter plasmid pSV-lacZ by lipofectamine plus reagents. The transient expressed viral proteins were identified at the transcription and translation levels. The activity of beta-galactosidase was detected, which reflected the transactivating function of the proteins. RESULTS: The protein expression of plasmids was detected in soluble cell extracts of transiently transfected HepG2 cells. HCV core protein activated the beta-galactosidase expression at a value of 4.6 times higher than the control, while C-terminally truncated HBV middle surface protein activated at a value of 3.2 times. It reached 8.4 times transfected with the plasmids simultaneously. The transactivating effect was dose dependent. CONCLUSIONS: It is suggested that the two kinds of virus proteins have transactivating effect on SV40 early promoter/enhancer, and they act synergistically. These contribute to explain the mechanisms of liver injury or tumorigenesis induced by HCV or/and HBV infection.

Hep G2 Cells↗
PubMed2002

[Screening and cloning gene of hepatocyte protein interacting with hepatitis C virus core protein].

OBJECTIVE: To clone the unknown gene of hepatocyte protein interacting with hepatitis C virus core protein. METHODS: Using the yeast dual hybrid system 3, bait plasmids of hepatitis C virus core were constructed. After identifying hepatitis C virus core protein that could stably expressed in AH109 yeast strains, we performed yeast two hybrid by mating AH109 with Y187 that transformed with liver cDNA library plasmids pACT2 and then plated on quadrople dropout (QDO) medium and assayed for alpha-gal activity. The genes of yeast colonies that could grow on QDO and had alpha-gal activity were sequenced. RESULTS: Among the 30 positive colonies, we blasted the gene of the sixth colony; we coined human hepatitis C virus binding protein 6(Hu Hcbp6) with Genbank, realized that the Hu Hcbp6 shares as much as 98% homology with two cDNA without knowing functions. We have proved that Hu Hcbp6 could interact with hepatitis C virus core protein. CONCLUSIONS: Hepatitis C virus core binding protein (Hu Hcbp 6 Genbank number: AY032594) was successfully cloned and identified. The study partly paved the way for investigating physiological function of the Hu Hcbp6.

Cloning, Molecular↗
PubMed2002

[Screening and application of human-derived HBsAg bacteriophage single chain antibody in clinical diagnosis].

OBJECTIVE: To identify human single chain Fv antibody (ScFv) against hepatitis B viral surface antigen. METHODS: The recombinant phages were panned by HBsAg which was coated in a microtiter plate, after five rounds of biopanning, 56 phage clones were identified specific to HBsAg. The specificity of ScFv was evaluated by ELISA and immunohistochemistry, respectively. RESULTS: The data of HB sAg-ScFv DNA digestion and DNA sequencing showed that the ScFv gene is composed of 750 bp. ELISA and immunohistochemistry demonstrated that the human single chain Fv antibody against hepatitis B surface antigen has a specific combination character with hepatitis B surface antigen of different sources and paraffin-embedded patients tissue specimens, it did not react with normal liver tissue and HCV. CONCLUSIONS: The application of HBsAg specific ScFv in immunohistochemistry was successfully achieved.

Bacteriophages↗