Biomedical subjects

Qing Zheng

Publications and source records attributed to Qing Zheng.

16 recordsLinked to original sources

PubMed2006

Site-directed PEGylation of human basic fibroblast growth factor.

Through site-directed mutagenesis, three cysteines of human basic fibroblast growth factor (hbFGF) were replaced with serine residues, resulting in a hbFGF mutant named hbFGFSer25,69,92. The mutant with only one cysteine residue at the 87th position, whose mitogenic activity was comparable to that of wild-type hbFGF, was further coupled to polyethylene glycol with a molecular size of 5 kDa (PEG5K) via the cysteine residue to obtain another hbFGF derivative, PEG5K-hbFGFSer25,69,92. The optimal modification reaction was conducted at 4 degrees C for 4 h at a molar ratio of PEG5K to hbFGFSer25,69,92 of 20:1. The result of SDS-PAGE showed that the modification extent was up to 80%. The modified product was purified by ion exchange chromatography. Compared to the hbFGF mutant, the purified PEG5K-hbFGFSer25,69,92 still retained about 60% of the mitogenic activity of the former, which provided a good basis for further studying the bioactivity of the PEGylated protein in vivo.

Animals↗

PubMed2006

[Effects of Helicobacter pylori infection on neural expression of stomach and spinal cord: an experiment with mice].

OBJECTIVE: To investigate the effects of Helicobacter pylori (Hp) infection on neural expression in stomach and spinal cord, and to investigate the mechanism of functional dyspepsia after Hp infection. METHODS: Thirty-five female C57BL/6 mice were randomly divided into three groups: Group A (acute infection group, undergoing intragastric gavage of Hp suspension every other day for 3 times and then observed for 2 weeks, 15 mice), Group B (chronic infection group, undergoing intragastric gavage of Hp suspension every other day for 3 times and then observed for 2 weeks, 15 mice) and control group (undergoing intragastric gavage of normal saline every other day for 3 times and then observed for 2 weeks, 5 mice). After the observation the mice were killed and their stomachs were taken out to undergo gastric histology and bacterial colonization by HE staining and Warthin-Starry staining respectively. Their spinal cords of thoracic and lumbar segments were taken out too. Immunohistochemistry was used to detect the expression of Fos, vasoactive intestinal polypeptide (VIP), and calcitonin gene-related peptide (CGRP) in the stomach and spinal cord. RESULTS: Three mice died 12 weeks after Hp infection. The rate of Hp colonization, mainly localized in pyloric gland region, was greater in Group B than in Group A, and was 0 in the control group. The severity of inflammation as shown by mononuclear cell infiltration, and activity of inflammation as shown by polymorphonuclear cell infiltration, in the pyloric gland region, proventriculus-glandular stomach region, and corpus gland region were more pronounced in Groups A and B, especially in Group B, than in the control group. The expression values of Fos, VIP, and CGRP in the stomach of Group A were 3.1 +/- 1.4, 4.5 +/- 1.8, and 2.4 +/- 0.8 respectively, all not significantly different from those of Group B (3.1 +/- 1.3, 3.5 +/- 1.6, and 2.2 +/- 0.8, all P > 0.05). The expression values of Fos, VIP, and CGRP in the spinal cord of Group A were 3.8 +/- 1.2, 3.2 +/- 1.5, and 2.2 +/- 0.6, all not significantly different from those of Group B (3.4 +/- 0.7, 2.6 +/- 1.2, and 2.5 +/- 1.1, all P > 0.05 for all). However, the neural expression values in both acute and chronic infection groups were significantly higher than those in the control group (2.4 +/- 0.9, 1.6 +/- 0.9, and 1.2 +/- 0.8 in stomach; and 2.0 +/- 1.6, 1.2 +/- 1.1, and 1.2 +/- 1.1 in spinal cord, P < 0.05 for all). CONCLUSION: Hp infection, both acute and chronic, induces gastric histological changes such as inflammation and activity, and enhances the Fos, VIP, and CGRP expression in stomach and spinal cord, which can be a basis for symptom generation in dyspeptic patients with Hp infection.

Animals↗

PubMed2006

High-level expression and purification of human epidermal growth factor with SUMO fusion in Escherichia coli.

Human epidermal growth factor (hEGF) can stimulate the division of various cell types and has potential clinical applications. However, the high expression of active hEGF in Escherichia coli has not been successful, as the protein contains three intra-molecular disulfide bonds that are difficult to form correctly in the bacterial intracellular environment. To solve this problem, we fused the hEGF gene with a small ubiquitin-related modifier gene (SUMO) by synthesizing an artificial SUMO-hEGF fusion gene that was highly expressed in Origami (DE3) strain. The optimal expression level of the soluble fusion protein, SUMO-hEGF, was up to 38.9% of the total cellular protein. The fusion protein was purified by Ni-NTA affinity chromatography and cleaved by a SUMO-specific protease to obtain the native hEGF, which was further purified by Ni-NTA affinity chromatography. The result of the reverse-phase HPLC showed that the purity of the recombinant cleaved hEGF was greater than 98%. The primary structure of the purified hEGF was confirmed by N-terminal amino acid sequencing and MALDI-TOF mass spectroscopy analysis. Using the method of methylthiazoletetrazolium, the mitogenic activity on Balb/c 3T3 cells of the purified hEGF was comparable to that of commercial hEGF.

Animals↗

PubMed2006

[Effect and mechanism of action of non-mitogenetic human acidic fibroblast growth factor on the mitogenic activity of the mammary tumor cell].

AIM: To compare the effects of the non-mitogenetic human acidic fibroblast growth factor (nmhaFGF) and the human acidic fibroblast growth factor (haFGF) on the proliferation and MAPK signal transduction pathway of the malignant tumor cell and to study the clinical safety of nmhaFGF. METHODS: The mammary tumor cells (MCF-7) were treated with haFGF and nmhaFGF separately. The mitogenic activities of both haFGF and nmhaFGF were detected by MTT method and the cell cycle was analyzed by flow cytometer (FCM). The expression levels of the signal proteins, Grb2 (growth factor receptor bound 2) and ERK1/2 (extracellular signal-regulated kinase 1/2), were detected by semi-quantitative Western blotting method. RESULTS: The mitogenic activity of nmhaFGF was obviously lower than that of haFGF. The activity of nmhaFGF was weaker than that of the haFGF. The ratio of G1/G0, G2/M of haFGF was markedly lower than that of nmhaFGF and control group, and was reverse in S phase. The expression levels of both Grb2 and ERK1/2 of the nmhaFGF treated group were lower than that of the haFGF treated group and approaching the control group. CONCLUSION: The mitogenic activity of the nmhaFGF decreased remarkably. Its mechanism probably via down-regulation of the expression of the signal moleculars, MAPK-ERK1/2 and Grb2.

Breast Neoplasms↗

PubMed2005

High-level expression and purification of a nonmitogenic form of human acidic fibroblast growth factor in Escherichia coli.

To decrease the potential side effects of acidic fibroblast growth factor (aFGF) caused by its broad-spectrum mitogenic activity, a nonmitogenic form of aFGF (nhaFGF), which retained the cardio- and neuroprotective characters of the wild-type aFGF, was overexpressed in Escherichia coli. The expression level of nhaFGF was up to 25% of the total cellular protein. The expressed nhaFGF was purified by ionic exchange and heparin affinity chromatography from the supernatant of bacteria lysate. The mitogenic activity of the purified nhaFGF was decreased dramatically comparable to that of the wild-type aFGF (haFGF) detected by methylthiazoletetrazolium method. The purified recombinant nhaFGF was sufficiently prepared and sufficient for the following pharmacological study.

Animals↗

PubMed2005

Comparison of the efficacy of 1-day high-dose quadruple therapy versus 7-day triple therapy for treatment of Helicobacter pylori infection.

BACKGROUND: The proton pump inhibitor (PPI)-based 7-day triple therapy is the regimen with the highest cure rates for eradication of Helicobacter pylori infection and has been recommended as the first-line regimen in the world. It had been reported that a 1-day quadruple therapy could also successfully cure 95% of the H. pylori infected patients. OBJECTIVES: To observe the efficacy of 1-day high-dose quadruple therapy versus 7-day triple therapy for treatment of H. pylori infection, and to observe side-effects of the two different regimens. METHODS: This randomized, open, parallel-controlled study was conducted at Renji Hospital between November 2004 to March 2005. A total of 80 consecutive patients with non-ulcer dyspepsia, who were H. pylori positive proven by both rapid urease test and histology were included and randomly assigned to 1-day quadruple therapy or 7-day triple therapy. Thirty-nine patients were administered with 1-day high-dose quadruple therapy including esomeprazole 40 mg b.i.d., colloidal bismuth subcitrate 440 mg q.i.d., amoxicillin 2 g q.i.d. and metronidazole (400 mg q.i.d.) for 1 day. Forty-one patients received a standard 7-day triple therapy consisting of esomeprazole 20 mg b.i.d., clarithromycin 500 mg b.i.d. and amoxicillin 1 g b.i.d. for 7 days. The eradication rates were evaluated by the (13)C-urea breath test at least 4 weeks after completion of a course treatment. RESULTS: Seventy-seven patients completed the trial and three patients dropped out. The eradication rates in the 1-day therapeutic group and the 7-day therapeutic group were 39.5% (15/38) and 84.6% (33/39), respectively. There was a statistically significant difference between the two groups (P < 0.0001). Short-lasting and self-limiting side effects including thirst, a metallic taste, diarrhea and abdominal pain were reported in three patients (7.9%) in the 1-day group and seven patients (18%) in the 7-day group (P = 0.31). CONCLUSIONS: A 1-day high-dose quadruple therapy with amoxicillin, metronidazole, bismuth salt, and esomeprazole is not effective for eradication of H. pylori compared with the standard 7-day triple therapy.

Adult↗

PubMed2005

Expression and purification of soluble non-fusion vasostatin in Escherichia coli.

Vasostatin has previously been expressed in fused form or in inclusion body form in Escherichia coli. Here the protein was expressed in soluble non-fusion form in BL21(DE3)pLysS by IPTG induction. The expression level of vasostatin was about 15% of the total cellular protein. The expressed vasostatin was purified and its biological activity was investigated by an endothelial cell proliferation assay.

Calreticulin↗

PubMed2005

[Rapid detection of three common deletional alpha thalassemias in Chinese by single-tube multiplex PCR].

OBJECTIVE: To develop a simple, rapid, accurate, and cost-effective single-0tube multiplex polymerase chain reaction (PCR) assay, which could be used for molecular screening and prenatal diagnosis, for detection of three commonest deletional alpha-thalassemias (-- (SEA), -alpha (3.7) and -alpha (4.2)) in Chinese population. METHODS: Four groups of primers were designed on the basis of gap-PCR, and the PCR reaction condition was optimized systematically with the purpose of amplifying effectively specific DNA fragments that are indicative of the respective genotypes of these three deletional alpha thalassemias. In addition, a pair of primers was designed to amplify LIS1 3' untranslated region (UTR) fragment for use as a separate control for amplification running. A total of 72 blood and prenatal archival DNA samples with various known alpha thalassemia genes or normal alpha globin gene sequence that had been confirmed by Southern blotting analysis or DNA sequencing were collected to test the specificity of this assay by blind analysis. In addition, DNA samples from nine couples at high risk of alpha thalassemia were also analyzed to evaluate the reliability of this technique in prenatal implementation. RESULTS: Homozygote, heterozygote and double heterozygote of the three commonest deletional alpha thalassemias were well detected simultaneously by this established method. For normal allele, a 2.4 kb amplified band as a systematic control and an alpha (2) gene-specific amplicon of 1.8 kb were produced. Besides the two amplified fragments of normal allele, it was found that a 1.3 kb, a 2.0 kb or a 1.6 kb amplified band could be simultaneously shown for representing --(SEA), -alpha (3.7) and -alpha (4.2) alleles, respectively, in the heterozygous states. In a blind test, this technique accurately detected 100% of the DNA samples previously characterized by Southern blotting or DNA sequencing, and it was successfully applied to prenatal diagnosis of alpha thalassemia in nine at-risk families. CONCLUSION: The single-tube multiplex PCR protocol presented in this study is easy-to-handle, rapid, reliable and is cost-effective for detecting --(SEA), -alpha (3.7) and -alpha (4.2) chromosomes, and it is suitable for large-scale population screening and for rapid molecular genotyping in clinics.

Asian People↗

PubMed2005

[Protective effect of non-mitogenic haFGF on retinal injury induced by N-methyl-N-nitrosourea in Sprague-Dawley rats].

AIM: To study the effect of non-mitogenic human acidic fibroblast growth factor (nm-haFGF) on retinal injury induced by N-methyl-N-nitrosourea (MNU) in Sprague-Dawley rats and its mechanism. METHODS: Female rats of 50-days-old were injected with MNU (60 mg x kg(-1)) intraperitoneally, and three doses of nm-haFGF (1.25 microg, 2.5 microg and 5 microg in one eye of each rat) were injected, separately, into vitreous body of one eye of each rat twice a day at 0 and 12 h after MNU treatment. 24 h later, apoptotic index of photoreceptor cells was detected by TUNEL labeling and the expressions of Bcl-2 and Bax were analyzed by Western blotting. At the 7th day, retinal injury was evaluated based on retinal thickness. RESULTS: Compared with model group, apoptotic index of photoreceptor cells was significantly reduced in nm-haFGF groups at the dose of 1.25 microg and 2.5 microg in one eye of each rat at 24 h, and the total retinal thickness as well as the outer retinal thickness markedly increased 7 days after MNU, respectively. The expressions of Bcl-2 increased and that of Bax decreased adversely after being injected with different doses of nm-haFGF. CONCLUSION: nm-haFGF partially suppressed retinal injury induced by MNU in Sprague-Dawley rats. The mechanism could be related to up-regulation of Bcl-2 and down-regulation of Bax.

Animals↗

PubMed2004

Preparation of microcapsules containing two-phase core materials.

Urea-formaldehyde (UF) microcapsules containing two-phase core materials in which phthalocyanine blue BGS (beta-CuPc) particles were homodispersed in tetrachloroethylene (TCE) were prepared by in situ polymerization. The effects of the various process parameters, including the type of surface modifier, the viscosity of UF prepolymer, the type of water-soluble surfactant, and the concentration of oil-soluble surfactant in the capsule core on the dispersity of beta-CuPc particles in TCE and the properties of the capsule wall and the adsorption of beta-CuPc particles on the internal surface of capsule wall were experimentally investigated. It was shown that using octadecylamine (ODA) to modify beta-CuPc particles resulted in a significant increase of the dispersing extent (DE) and the electrophoresis velocity of the particles in TCE (about 4 and 20 times more than that of unmodified). In addition, the optimal reaction conditions of the synthesis UF prepolymer were obtained by the orthogonal test. On the other hand, as the oil/water interfacial tension of emulsion was big enough, the microcapsule formed. The concentration of Span-80 in TCE was no less than 0.062 mM; the adsorption of beta-CuPc particles on internal surface of wall were restrained. Finally, the microcapsules in which beta-CuPc particles possess reversible response to dc electric field were obtained.

Amines↗

PubMed2004

Direct neural network application for automated cell recognition.

BACKGROUND: Automated cell recognition from histologic images is a very complex task. Traditionally, the image is segmented by some methods chosen to suit the image type, the objects are measured, and then a classifier is used to determine cell type from the object's measurements. Different classifiers have been used with reasonable success, including neural networks working with data from morphometric analysis. METHODS: Image data of cells were input directly into neural networks to determine the feasibility of direct classification by using pixel intensity information. Several types of neural network and their ability to work with cells in a complex patterned background were assessed for a variety of images and cell types and for the accuracy of classification. RESULTS: Inflammatory cells from animal biomaterial implants in rabbit paravertebral muscle were imaged in histologic sections. Simple, three-layer, fully connected, back-propagation neural networks and four-layer networks with two layers of a shared-weights neural network were most successful at classifying the cells from the images, with 97% and 98% correct recognition rates, respectively. CONCLUSIONS: The high accuracy recognition rate shows the potential for direct classification of visual image pixel data by neural networks.

Animals↗

PubMed2004

Development of gastric adenocarcinoma in Mongolian gerbils after long-term infection with Helicobacter pylori.

BACKGROUND AND AIM: The experimental evidence that long-term colonization of Helicobacter pylori results in the development of gastric cancer in Mongolian gerbils has been reported only by two Japanese groups to date. This study aimed to investigate the carcinogenicity of H. pylori infection in a Mongolian gerbil model. METHODS: Thirty-six Mongolian gerbils (inner Mongolian origin) were divided into two groups (male to female ratio, 1:1) and orally inoculated with a standard H. pylori strain (ATCC43504) or H. pylori161 (isolated from a Chinese patient with gastric adenocarcinoma), respectively, once a week for 5 weeks. Another 10 control gerbils were given phosphate-buffered saline. The animals were killed 8, 20, 28 and 84 weeks after inoculation for bacterial and histological examination. RESULTS: Seven inoculated gerbils died at the week 42. Overall, H. pylori colonization was detected in 24 (83%) of the 29 available inoculated gerbils. The gastric lesions were aggravated gradually over time. At week 84, moderate to severe gastritis, characterized by diffuse infiltration of mononuclear cells and formation of multiple lymphoid follicles in mucosa and submucosa, and even the lymphoepithelial lesions, were observed. Epithelial hyperplasia were dominant in almost all gerbils. Four (24%) of the 17 animals had hyperplastic polyps. Intestinal metaplasia were rarely seen (in three gerbils). Well-differentiated gastric adenocarcinomas developed in three (18%) of the 17 gerbils after 84 weeks. Of the three gerbils, one female gerbil was infected with H. pylori161 and the others (one male and one female) were infected with ATCC43504. CONCLUSIONS: The present study reconfirms that H. pylori infection alone can induce gastric adenocarcinoma in Mongolian gerbils and suggests that different species of gerbil and both standard and clinically isolated H. pylori strains can be used for investigating the carcinogenesis of H. pylori. This is the first report of the development of gastric cancer in female gerbils, which highlights the importance of using both sexes to investigate the pathogenesis of H. pylori and whether host susceptibility is influenced by sex.

Adenocarcinoma↗

PubMed2004

[An analysis about the safe range of thickness of the residual corneal stroma bed after LASIK].

OBJECTIVE: To ascertain the safe range of thickness of the residual corneal stroma bed and the length of stable time after LASIK operation. METHODS: Two hundred and twenty seven eyes were randomly selected from cases treated with LASIK in 2000. The posterior curvature of cornea was measured by Obscan II preoperatively and 1, 2, 3, 6 months, 1 year and 2 year postoperatively. These data were compared and analyzed. RESULTS: Ectasia of central corneal posterior surface was detected at different degrees in all cases at the early postoperative period after LASIK. Ectasia was more prominent in eyes with thinner corneal stroma bed (< 300 microm). In eyes with thicker corneal stroma, ectasia remained stable or reverting obviously during the first year. The posterior curvature of cornea had no significant difference between 1 year and 2 year after operation in all cases. CONCLUSIONS: Ectasia of corneal posterior surface presents in the early postoperative period after LASIK. It is safer to reserve more than 300 microm of the corneal stroma bed. The posterior curvature of cornea of all cases remains stable after one year postoperatively.

Adolescent↗

PubMed2003

[An analysis of measurement error in Orbscan topography system].

OBJECTIVE: To discuss the measurement error and the influence factor of Orbscan Topography to provide more accurate data for clinical application. METHODS: Orbscan Topography System and A-scan ultrasonography were used to measure the corneal thickness and anterior chamber depths pre-operatively and post-operatively, including 200 cases (400 eyes) undergoing laser in situ keratomileusis (Lasik) and 50 cases (100 eyes) undergoing photorefractive keratectomy (PRK). The curvature of posterior corneal surface was measured by Orbscan topography before and after the operations, and the result of measurement was compared. RESULTS: Pre-operatively, the value of corneal thickness was (18.83 - 24.29) microm lower measured by Orbscan topography than that by A-ultrasonography, and post-operatively the value was (56.32 - 139.52) micro m lower than that by A-ultrasonography. The postoperative value was obviously higher than the pre-operative one. The value of central anterior chamber depth was (0.16 - 0.25) mm lower measured by Orbscan system than that by A-ultrasonography pre-operatively and post-operatively. There was no clinical significance. The difference in the comparison of posterior corneal surface curvature before and after Lasik was -0.60 D measured by Orbscan System. The difference in the comparison of posterior corneal surface curvature before and after PRK was -0.51 D in the lower diopter group and -1.12 D in medium diopter group. CONCLUSIONS: It is necessary to improve the accuracy of Orbscan Topography System. The Haze and the change of anterior corneal surface curvature after Lasik and PRK are the main causes of measurement error in Orbscan Topography System. Clinically, it is an un-negligible important problem in the measurement of Orbscan system.

Adolescent↗

PubMed2002

[Pharmacokinetic study of recombinant human acidic fibroblast growth factor in rabbits by skin external use].

AIM: To investigate the pharmacokinetic characteristics of recombinant human acidic fibroblast growth factor (rhaFGF) after external use in rabbits. METHODS: 125I-rhaFGF 180 U.cm-2 was daubed to normal skin and scathed skin in rabbits. The radioactivity and paper chromatography were used to determine the 125I-concentrations and distribution in plasma and organs at different times. RESULTS: The plasma concentration of 125I-rhaFGF increased rapidily, and reach peak plasma level (73.03 pg.mL-1) thirty minutes after administration. Then the concentration of 125I-rhaFGF decreased quickly after thirty minutes, and approached to zero after three hours. Highest radioactivity accumulated in the skin, followed by kidney, lowest in the brain 96 h after administration. CONCLUSION: rhaFGF can not be absorbed from the normal skin, whereas a small amount of rhaFGF can be absorbed through scathed skin. The t1/2 of rhaFGF in plasma was very short. Cumulative effect of rhaFGF was not observed. Absorbed rhaFGF showed high affinity to skin, and can be distributed to skin far from the site of administration.

Administration, Cutaneous↗

PubMed2002

[Protective effect of tea pigments on mice skin photoaging induced by UV irradiation].

OBJECTIVE: To study the protective effect of tea pigments on mice skin photoaging induced by UV irradiation. METHOD: Total antioxidative ability and content of lipid peroxidation products malondialdehyde in the skin of mice were examined with colorimetry. RESULT: By ig or smearing, tea pigments could significantly improve total antioxidative ability and decline content of malondialdehyde in UV-irradiation-induced skin photoaging mice. CONCLUSION: The results suggested that tea pigments could prevent mice skin from free radicals injury resulting from UV irradiation and moderate skin photoaging.

Animals↗