Biomedical subjects

C Zheng

Publications and source records attributed to C Zheng.

At least 91 records · Page 5Linked to original sources

PubMed2000

[The study on the anti-osteoporosis effect of clodronate in ovariectomized rats].

To evaluate the anti-osteoporosis effect of clodronate in ovariectomized rats, 44 female Wistar rats, aged 8 months, were divided randomly into 4 groups: the SHAM group (subjected to sham operation); the OVX group (subjected to bilateral ovariectomy); the E3 group (subjected to bilateral ovariectomy and treated after surgery with nilestriol 1 mg/kg BW by gavage once a week for 12 weeks), and the clodronate group (subjected to bilateral ovariectomy and treated after surgery with clodronate 5 mg/kg BW by subcutaneous injection twice a week for 12 weeks). All the animals were sacrificed 12 weeks after the operation. The blood and urine samples were collected for determination of biochemical indices. The humeri and tibiae were prepared for determination of net weight, ash weight, calcium and phosphorus content, bone density, as well as bone histopathology and histomorphometry. The left femora were processed for bone anti-curve power. The results showed that as compared with the SHAM group, the net weight, ash weight, calcium content, density and anti-curve power of bones, te trabecular bone volume and thickness were all significantly reduced in the OVS group, while its osteoblast index, osteoclast index and urine hydroxyproline content were obviously close to normal levels. The data indicates that both clodronate and E3 can effectively prevent bone loss in ovariectomized rats.

Animals↗

PubMed2000

Congenital choledochal cyst--report of 56 cases.

OBJECTIVE: The aim of this paper is to describe the mechanism, clinical manifestation, diagnosis and surgical management of congenital choledochal cyst. METHODS: From 1984 to 1997, 56 cases of congenital choledochal cyst were reviewed. Among them, 8 patients were male, 48 patients were female, the age ranges from 12 to 50 years old with an average of 26.3. RESULTS: The main clinical manifestation includes jaundice, abdominal pain and abdominal mass. All of them were confirmed by ultrasonography, while 39 cases were performed ERCP and PTC with the same diagnosis. Fifty-one patients were performed cystectomy and hepatojejunostomy, two cases were performed cystjejunostomy because of diffused angioma and severe hemorrhage respectively, external drainage was performed in one case with emergent cholangitis, the other two cases were reported malignancy through biopsy and operation was abandoned. CONCLUSIONS: Ultrasound diagnostics is essential to accurately diagnose the cyst, preoperative ERCP is helpful for differentiating pancreatic duct from bile duct, while MRCP is a reliable method; cystectomy and cholangiojejunostomy is recommended, laparoscopic procedure is becoming more and more accepted.

Adolescent↗

PubMed2000

[Prevention and management of complications with laparoscopy cholecystectomy].

OBJECTIVE: To prevent the complication of laparoscopy cholecystectomy (LC). METHODS: This text analysed 1,200 cases retrospectively with LC from Feb. 1993 to May. 1998. RESULTS: Three cases with biliferous duct injury, two cases with bile leakage from the stamp of cystic duct, two cases with gallbladder artery injury. CONCLUSIONS: Strict preoperative examination and standard operative procedure can reduce markedly complication of LC.

Bile Ducts↗

PubMed2000

Diagnosis and treatment of insidious recurrent small intestinal hemorrhage.

OBJECTIVE: To improve the localized diagnosis of insidious recurrent small intestinal hemorrhage. METHODS: This retrospective analysis include 64 cases of such diseases, which were admitted from 1988 to 1998 to our hospital. RESULT: Ultrasonography, CT, small bowel pneumobariumgraphy, diluted barium enema, isotopic examination, DSA and intraoperative small-bowel endoscopy were used for diagnosis of hemorrhagic site, and 37 cases got a definite location before operation, while 10 cases were confined the diagnosis during the operation. Forty-seven cases were treated surgically, while the other 17 cases had non-surgical treatment. Of the 47 cases, 39 cases underwent partial enterectomy, 5 cases had suture and ligature of vascular deformity, 2 cases had Whipple's operation, and one patient had ectomy of the end of ileum and right colon. CONCLUSION: DSA, Isotopic examination and intraoperative enteroscopy are of considerable importance for the location judgement of recurrent small intestinal hemorrhage.

Adolescent↗

PubMed2000

[Analysis of trace elements contents in dry-fruit of xinjiang].

Ten kinds of trace element's contents in nine kinds of specialities of Xinjiang were measured by flame atomic absorption spectrometry and flame atomic emission spectrometry. The trace element's contents in these different specialities were compared with each other. The relationships between the over-accumulation of trace element in body and some illness of people were also studied. Statistics suggest that there are different contents of the ten kinds of trace elements in every kinds of dry-fruit. The statistics are valuable references.

China↗

PubMed2000

[Determination of nine microelements in the human hair of three ethnic groups].

Nine microelements--Zn, Cu, Fe, Mn, Sr, Mg, K, Na and Ca in human hair of three ethnic groups--Han, Uigur and Hazak between male and female were determined by flame atomic absorption spectrometry. The contents of K, Na, Ca, Mg and Sr were different in different ethnic groups, and the quantities of K, Na and Sr are also very different between sexual distinction.

Calcium↗

PubMed1999

Polymorphisms at - 174 and in the 3' flanking region of interleukin-6 (IL-6) gene in patients with myasthenia gravis.

We examined the bi-allelic polymorphism at - 174 in the promoter region and the polymorphism in the 3' flanking AT rich region of the interleukin-6 (IL-6) gene in Swedish patients with myasthenia gravis (MG) and ethnically matched healthy individuals. There was no association between the polymorphisms and the disease. There was no relation of the polymorphisms to the clinical variables, the thymic histopathologies, the level of serum acetylcholine receptor antibodies or the concentrations of IgG and its subclasses. Our data yield no evidence for the IL-6 gene contributing to the disease susceptibility.

AT Rich Sequence↗

PubMed1999

The JNKK2-JNK1 fusion protein acts as a constitutively active c-Jun kinase that stimulates c-Jun transcription activity.

c-Jun N-terminal protein kinase (JNK), a member of the mitogen-activated protein (MAP) kinase family, regulates gene expression in response to various extracellular stimuli. JNK is activated by JNK-activating kinase (JNKK1 and JNKK2), a subfamily of the dual specificity MAP kinase kinase (MEK) family, through phosphorylation on threonine (Thr) 183 and tyrosine (Tyr) 185 residues. The physiological functions of the JNK pathway, however, are not completely understood. A major obstacle is the lack of specific and activated kinase components that can stimulate the JNK pathway in the absence of any stimulus. Here we show that fusion of JNK1 to its upstream activator JNKK2 resulted in its constitutive activation. In HeLa cells, the JNKK2-JNK1 fusion protein showed significant JNK activity, which was comparable with that of JNK1 activated by many stimuli and activators, including EGF, TNF-alpha, anisomycin, UV irradiation, MEKK1, and small GTP binding proteins Rac1 and Cdc42Hs. Immunoblotting analysis indicated that JNK1 was phosphorylated by JNKK2 in the fusion protein on both Thr(183) and Tyr(185) residues. Like JNKK2, the JNKK2-JNK1 fusion protein was highly specific for the JNK pathway and did not activate either p38 or ERK2. Transient transfection assays demonstrated that the JNKK2-JNK1 fusion protein was sufficient to stimulate c-Jun transcriptional activity in the absence of any stimulus. Immunofluorescence analysis revealed that the JNKK2-JNK1 fusion protein was predominantly located in the nucleus of transfected HeLa cells. These results indicate that the JNKK2-JNK1 fusion protein is a constitutively active Jun kinase, which will facilitate the investigation of the physiological roles of the JNK pathway.

Fluorescent Antibody Technique↗

PubMed1999

Multipoint linkage disequilibrium mapping with particular reference to the African-American population.

A new approach to scanning the genome is presented to detect linkage disequilibrium caused specifically by population admixture. In contrast to current linkage genome scanning methods to find causal genes for complex diseases, this new method should be powerful to find genes for multilocus traits, particularly those genes that lead to the highest population attributable risk. Such a scan using the African-American population is generally feasible for mapping common diseases. A conservative threshold is also provided for such association mapping.

Alleles↗

PubMed1999

Identification of T-DNA tagged Arabidopsis mutants that are resistant to transformation by Agrobacterium.

We have identified T-DNA tagged Arabidopsis mutants that are resistant to transformation by Agrobacterium tumefaciens (rat mutants). These mutants are highly recalcitrant to the induction of both crown gall tumors and phosphinothricin-resistant calli. The results of transient GUS (beta-glucuronidase) assays suggest that some of these mutants are blocked at an early step in the Agrobacterium-mediated transformation process, whereas others are blocked at a step subsequent to translocation of T-DNA into the nucleus. Attachment of Agrobacterium to roots of the mutants rat1 and rat3 was decreased under various incubation conditions. In most mutants, the transformation-deficient phenotype co-segregated with the kanamycin resistance encoded by the mutagenizing T-DNA. In crosses with susceptible wild-type plants, the resistance phenotype of many of these mutants segregated either as a semi-dominant or dominant trait.

Agrobacterium tumefaciens↗

PubMed1999

Adenovirus-mediated TNF-alpha gene transfer induces significant tumor regression in mice.

Recombinant adenovirus vectors are highly efficient at in vitro and in vivo gene delivery. The in vitro infection of a mouse colon adenocarcinoma cell line MCA-26 with the adenovirus AdV-LacZ can reach a maximal 75% of infectivity at an MOI of 1000. Intratumoral injection of AdV-LacZ (2X10(9) pfu) resulted in substantial gene transfer in nearly 70% of MCA-26 tumors. After the in vitro infection of AdV-TNF-alpha, infected MCA-26 cells showed significant secretion of TNF-alpha (45 ng/ml/10(6) cells) in tissue culture. The secretion peaks at day 2 and is diminished at day 4 following the viral infection. Infected MCA-26 tumor cells secreting TNF-alpha significantly reduced their tumorigenicity in syngeneic BALB/c mice. In mice bearing small tumors, intratumoral injection of 2X10(9) pfu of AdV-TNF-alpha virus with a repeated booster treatment resulted in complete regression of three tumors and significant diminution of the other two with a mean tumor-weight of 0.16 g; this is in contrast to 0.85 and 1.62 g for tumors injected with the control AdV-pLpA and PBS respectively (p < 0.01). Mice with complete tumor regression further developed protective immunity against the second challenge of MCA-26 inoculation. In mice bearing large tumors, this treatment also caused significant inhibition of tumor growth with a mean tumor weight of 0.65 g vis-a-vis 3.05 g for tumors injected with the control AdV-pLpA. On the contrary, in mice bearing large tumors, the treatment of tumors with pCI-TNF-alpha delivered by the gene gun did not induce significant tumor inhibition. These results indicate that the adenoviral delivery of TNF-alpha gene is more efficient than the particle-mediated gene gun device, and that adenovirus-mediated cytokine gene therapy may be a useful approach in the clinical management of human solid tumors.

Adenocarcinoma↗

PubMed1999

The Mycobacterium tuberculosis small heat shock protein Hsp16.3 exposes hydrophobic surfaces at mild conditions: conformational flexibility and molecular chaperone activity.

Hsp16.3, the alpha-crystallin-related small heat shock protein of Mycobacterium tuberculosis that is maximally expressed during the stationary phase and is a major membrane protein, has been reported to form specific trimer-of-trimers structure and to act as an effective molecular chaperone (Chang Z et al., 1996, J. Biol Chem 271:7218-7223). However, little is known about its action mechanism. In this study, Hsp16.3 conformational intermediates with dramatically increased chaperone activities were detected after treatment with very low concentrations of guanidine hydrochloride (0.05 M), urea (0.3 M), or mild heating (30 degrees C). The intermediates showed a significant increase in their capacity to bind the hydrophobic probe 1-anilino-8-naphthalene sulfonate (ANS), indicating an increased exposure of hydrophobic surfaces. Interestingly, the greatest chaperone activities of Hsp16.3 were observed in the presence of 0.3 M guanidine HCl or when heated to 35 degrees C. CD spectroscopy studies revealed no significant changes in protein secondary and tertiary structures at these mild treatments. Our in vitro studies also indicate that long-time-heated Hsp16.3, heated even to temperatures as high as 85 degrees C, has almost the same, if not a slightly greater, chaperone activities as the native protein when cooled to room temperature and its secondary structures also almost recovered. Together, these results suggest that Hsp16.3 modulates its chaperone activity by exposing hydrophobic surfaces and that the protein structure is highly stable and flexible, thus highly adapted for its function.

Anilino Naphthalenesulfonates↗

PubMed1999

Structural basis of neurophysin hormone specificity: Geometry, polarity, and polarizability in aromatic ring interactions.

The structural origins of the specificity of the neurophysin hormone-binding site for an aromatic residue in peptide position 2 were explored by analyzing the binding of a series of peptides in the context of the crystal structure of liganded neurophysin. A new modeling method for describing the van der Waals surface of binding sites assisted in the analysis. Particular attention was paid to the unusually large (5 kcal/mol) difference in binding free energy between Phe and Leu in position 2, a value representing more than three times the maximum expected based on hydrophobicity alone, and additionally remarkable since modeling indicated that the Leu side chain was readily accommodated by the binding pocket. Although evidence was obtained of a weak thermodynamic linkage between the binding interactions of the residue 2 side chain and of the peptide alpha-amino group, two factors are considered central. (1) The bound Leu side chain can establish only one-third of the van der Waals contacts available to a Phe side chain. (2) The bound Phe side chain appears to be additionally stabilized relative to Leu by more favorable dipole and induced dipole interactions with nonaromatic polar and sulfur ligands in the binding pocket, as evidenced by examination of its interactions in the pocket, analysis of the detailed energetics of transfer of Phe and Leu side chains from water to other phases, and comparison with thermodynamic and structural data for the binding of residue 1 side chains in this system. While such polar interactions of aromatic rings have been previously observed, the present results suggest their potential for significant thermodynamic contributions to protein structure and ligand recognition.

Amino Acids↗

PubMed1999

Effect of clodronate on macrophage depletion and adenoviral-mediated transgene expression in salivary glands.

Expression of transgenes from adenoviral vectors is short-lived in salivary glands, in part because of immune responses to the virus and/or transgene product. Previous studies demonstrated that depletion of macrophages with multilamellar liposomes containing clodronate (Cl2MBP) increases adenoviral-mediated transgene expression in the liver. This technique was tested in salivary glands. Rats were treated with Cl2MBP-liposomes or control liposomes by femoral vein, intraperitoneal, or carotid artery injections. Thereafter, a recombinant adenovirus, AdCMVluciferase, was instilled intraductally in submandibular glands (SMGs), or delivered to the liver via femoral vein injection. Marked depletion (>94%) of liver macrophages and increased levels of luciferase activity in the liver (45-fold higher than controls) were present in animals receiving Cl2MBP-liposomes. In contrast, the same treatment never depleted more than 41% of SMG macrophages nor increased luciferase activity in SMGs, regardless of the route of administration. In conclusion, while macrophage depletion with Cl2MBP-liposomes is associated with markedly increased adenoviral-mediated transgene expression, this strategy was ineffective for salivary glands.

Adenoviridae↗

PubMed1999

[Research on stochastic factors of heart rhythm variability in nonlinear dynamic analysis].

In this study, the influence of external noise on heart rhythm variability (HRV) in nonlinear dynamic analysis and the internal stochastic factor of HRV were discussed in connection with their physiological significance. The sampling rate, stationary and non-uniformity time interval were analyzed. An interpolation algorithm for heart period was introduced. The experiment demonstrated that the influence was highly reduced by the mentioned procedure. The internal stochastic factors of HRV were investigated by several nonlinear dynamic methods such as surrogate data, mutual information and nonlinear forecasting. The results suggested the colligation of deterministic chaos and stochastic process should be a favorite to interpret HRV.

Electrocardiography↗

PubMed1999

[Surgical treatment of gastric cancer in stage T1/T2: an reevaluation of the clinical significance of early gastric cancer].

OBJECTIVE: To evaluate the clinical significance of early gastric cancer by means of an analysis of the results of surgical treatment of gastric cancer in stage T1/T2. METHODS: A retrospective review and survival analysis of 132 patients with stage T1/T2 stomach cancer treated from 1983 through 1993 was performed. RESULTS: The average tumor size, lymph node involvement, postoperative recurrence and survival rate were significantly different between gastric cancer in stage T1 and T2. It was true of both groups of patients that the survival rate of patients with and without lymph node involvement was significantly different. However, the survival rate of patients in stage T2 but without lymph node involvement was not significantly different as compared to that of patients in stage T1. CONCLUSION: For stage T1 stomach cancer, because of possible lymph node involvemnt, local mucosal excision of tumor is not recommended. For stage T2 stomach cancer without lymph node metastasis, it can be regarded as cancer still in its early stage when postoperative adjunct therapy is to be given.

Adult↗

PubMed1999

[Usefulness of CYFRA21-1 as a tumor marker of non-small-cell lung cancer].

OBJECTIVE: To evaluate the clinical usefulness of CYFRA21-1 as a serum tumor marker in diagnosis, evaluation of clinical status and prognosis of patients with non-small-cell lung cancer (NSCLC). METHODS: CYFRA21-1 in 126 serum samples of NSCLC patients was measured by radioimmunoassay. Of the 126 samples, 71 were collected before treatment, 29 at two weeks after operation, and 26 after 15-18 months follow-up. RESULTS: CYFRA21-1 was positive in 49.3% of the NSCLC patients who had not received any treatment. The positive rate was 69.2% for squamous-cell carcinoma, and 25.0% for adenocarcinoma. The serum level of CYFRA21-1 was significantly higher in squamous-cell carcinoma than in adenocarcinoma (P < 0.0001). The serum level of CYFRA21-1 well correlated and increased with TNM staging (P = 0.0001). The level decreased significantly within two weeks after surgical operation in 29 cases (P = 0.0005). On follow up for 15-18 months, no change in CYFRA21-1 level was observed in 16 patients whose disease was stable, while there was significant increase in 10 patients with progressive disease. CONCLUSION: CYFRA21-1 is a soluble fragment of cytokeratin 19 in serum of patients with NSCLC. It can be used as a useful tumor marker of NSCLC.

Adolescent↗

PubMed1999

[Endoscopic treatment of sphenoidal and ethmoidal mucoceles].

OBJECTIVE: To evaluate endoscopic surgery for sphenoidal and ethmoidal mucoceles. METHOD: Seventeen patients diagnosed as having paranasal sinus mucoceles underwent attempted endoscopic marsupialization between 1989 and 1995. Ten of the mucoceles were in the sphenoid sinus, seven in the ethmoid sinus. Postoperative endoscopic follow-up period varied from 3 to 9 years. RESULT: All the sphenoidal and ethmoidal mucoceles were satisfactorily approached endoscopically. Postoperative endoscopic examination manifested all the operating cavity was satisfactorily marsupialized. The symptoms were improved or relieved in 15 patients. None of the patients undergoing endoscopic surgery had significant complications. CONCLUSION: Our results show that endoscopic surgery seems to be a safe, valuable way for management of sphenoidal and ethmoidal mucoceles.

Adult↗