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Li Zeng

Publications and source records attributed to Li Zeng.

At least 55 records · Page 3Linked to original sources
PubMed2003

Identification of a novel human doublecortin-domain-containing gene (DCDC1) expressed mainly in testis.

Mutations in the X-linked gene doublecortex (DCX) result in lissencephaly in males or subcortical laminar heterotopia (double cortex) in females. Recently, an evolutionarily conserved doublecortin (DC) domain important for microtubule binding and microtubule polymerization was defined according to detailed sequence analysis of DCX and DCX-like proteins. Subsequently we cloned a novel human cDNA that contained a DC domain during large-scale DNA sequencing of the human fetal brain cDNA library, and termed it doublecortin-domain-containing 1 (DCDC1). According to a search against the human genome database, DCDC1 was mapped to 11p13. Expression analysis showed that DCDC1 was mainly expressed in adult testis. Furthermore, the expression level of DCDC1 in fetal brain was much higher than in adult brain.

Amino Acid Sequence↗
PubMed2003

[Effect of different methods for postoperative pain management on catecholamine response to abdominal surgery].

OBJECTIVE: To observe the effect of different analgesic methods and the influence of catecholamine response to elective abdominal surgery. METHODS: 42 ASA I-II patients undergoing elective abdominal surgery were randomly divided into five groups. After receiving combined general and epidural anesthesia, postoperative patient-controlled epidural analgesia was provided in group RF, BF, BM with 1.2 g.L-1 ropivacaine + 2 mg.L-1 fentanyl, 1.2 g.L-1 bupivacaine + 2 mg.L-1 fentanyl, 1.2 g.L-1 bupivacaine + 80 mg.L-1 morphine respectively. Group EM received general-epidural anesthesia and patient-controlled intravenous analgesia with 0.5 g.L-1 morphine. Levels of analgesics (VAS, VRS), plasma concentrations of adrenaline and noradenaline were measured. RESULTS: Effective analgesia could be achieved in all groups. VAS in groups BM and M was significantly less than that in groups RF, and VRS in groups BM was higher than that in groups RF, EM and M. There were more side effects in groups BM, M and EM, and the incidence of nausea was highest in group M(5 cases). The adrenaline concentrations in group BM one hour postoperation was lower than that in group BF, and noradrenaline in group EM was lower than that in group RF. The 24-hour postoperative values of the adrenaline and noradrenaline in group M were higher than their preoperative values. CONCLUSIONS: Postoperative patient-controlled epidural or intravenous analgesia could provide effective analgesia. Epidural anesthesia during operation or epidural analgesia postoperation could depress stress responses, thus it is a more effective analgesic method.

Abdomen↗
PubMed2003

Molecular cloning and characterization of a novel dual-specificity phosphatase18 gene from human fetal brain.

Dual-specificity protein phosphatases (DSPs), a new family of protein tyrosine phosphatases (PTPs), are characterized by the ability to dephosphorylate both phospho-tyrosyl and phospho-seryl/threonyl residues. It has been known that most of the enzymes play important roles in the regulation of mitogenic signal transduction and control the cell cycle in response to extracellular stimuli. In this study, a novel human DSP gene named Dual-specificity Phosphatase18 (DUSP18) was isolated by large-scale sequencing analysis of a human fetal brain cDNA library. DUSP18 is localized at Chromosome 22 q12.1. Its cDNA is 2450 base pairs in length, encoding a 188-amino acid polypeptide in which a DSP motif but not a CH2 domain is included. RT-PCR revealed that the DUSP18 was widely expressed in different tissues. GST-DUSP18 fusion protein showed distinctive phosphatase activity toward p-nitrophenyl phosphate (pNPP), as well as oligopeptides containing pThr and pTyr, indicating that DUSP18 is a protein phosphatase with dual substrate specificity. The optimal condition for the reaction was pH 6.0 and 55 degrees C. Addition of Mn(2+) ions was able to enhance the enzyme activity while the activity was strongly inhibited by iodoaretic acid. Mutations in selected sites showed the importance of Asp-73, Cys-104, Arg-110 and Ser-111 in phosphatase activity of DUSP18.

Amino Acid Sequence↗
PubMed2003

PTP alpha regulates integrin-stimulated FAK autophosphorylation and cytoskeletal rearrangement in cell spreading and migration.

We investigated the molecular and cellular actions of receptor protein tyrosine phosphatase (PTP) alpha in integrin signaling using immortalized fibroblasts derived from wild-type and PTP alpha-deficient mouse embryos. Defects in PTP alpha-/- migration in a wound healing assay were associated with altered cell shape and focal adhesion kinase (FAK) phosphorylation. The reduced haptotaxis to fibronectin (FN) of PTP alpha-/- cells was increased by expression of active (but not inactive) PTP alpha. Integrin-mediated formation of src-FAK and fyn-FAK complexes was reduced or abolished in PTP alpha-/- cells on FN, concomitant with markedly reduced phosphorylation of FAK at Tyr397. Reintroduction of active (but not inactive) PTP alpha restored FAK Tyr-397 phosphorylation. FN-induced cytoskeletal rearrangement was retarded in PTP alpha-/- cells, with delayed filamentous actin stress fiber assembly and focal adhesion formation. This mimicked the effects of treating wild-type fibroblasts with the src family protein tyrosine kinase (Src-PTK) inhibitor PP2. These results, together with the reduced src/fyn tyrosine kinase activity in PTP alpha-/- fibroblasts (Ponniah et al., 1999; Su et al., 1999), suggest that PTP alpha functions in integrin signaling and cell migration as an Src-PTK activator. Our paper establishes that PTP alpha is required for early integrin-proximal events, acting upstream of FAK to affect the timely and efficient phosphorylation of FAK Tyr-397.

Adenoviridae↗
PubMed2003

Identification of a novel human angiopoietin-like gene expressed mainly in heart.

The angiopoietins are an important family of growth factors specific for vascular endothelium. Most of them bind to the TIE2 receptor and are related to regulation of angiogenesis. During large-scale DNA sequencing of the human fetal brain cDNA library, we cloned a novel human angiopoietin-like cDNA and termed it human angiopoietin-like 5 ( ANGPTL5). Like other members of the angiopoietin family, ANGPTL5-deduced protein also has an N-terminal cleavable signal peptide, a predicted coiled-coil domain, and a fibrinogen-like domain. The search against the human genome database indicated that ANGPTL5 maps to 11q22. Expression analysis of ANGPTL5 shows that it is mainly expressed in adult human heart.

Amino Acid Sequence↗
PubMed2003

Cloning and expression of a novel human C5orf12 gene*, a member of the TMS_TDE family.

We report here cloning and characterization of a novel human gene, termed C5orf12, which is a putative membrane protein belonging to the TMS_TDE family. The cDNA encodes 423 amino acid with a putative molecular weight of about 47 KDa. Secondary structure prediction showed that C5orf12 contained 10 putative transmembrane helices, which has high identity with other family members. We performed RT-PCR to examine its expression pattern. The result showed that C5orf12 was highly expressed in placenta, skeletal muscle, spleen, thymus, testis and peripheral leukocyte while expressed weakly in heart and liver. C5orf12 has high identity with the rat TPO1, so we speculate that C5orf12 may also have a role in the brain development.

Amino Acid Sequence↗
PubMed2003

Molecular cloning and characterization of a novel human hydroxysteroid dehydrogenase-like 2 (HSDL2) cDNA from fetal brain.

Hydroxysteroid dehydrogenases (HSDs) are responsible for the biosynthesis of steroid hormones and play a crucial role in mammalian physiology and development. By large-scale sequencing analysis of a human fetal brain cDNA library, we isolated a novel human hydroxysteroid dehydrogenase-like cDNA (HSDL2). This cDNA is 3211 bp in length, encoding a 418-amino-acid polypeptide, which contains a typical motif for NAD(P)+-binding (TGxxxGxG), an SDR active site motif (S-Y-K) and a sterol carrier protein domain. HSDL2 shows high similarity with the homologues in the mouse and fruit fly. The HSDL2 gene is mapped to chromosome 9q32 and contains 11 exons. RT-PCR analysis shows that the HSDL2 gene is widely expressed in human tissues and the expression levels in liver, kidney, prostate, testis, and ovary are relatively high.

Amino Acid Motifs↗
PubMed2003

Isolation and characterization of a human putative receptor protein kinase cDNA STYK1.

Protein kinases (PKs) represent a well studied but most diverse protein superfamily. The covalent, reversible linkage of phosphate to serine, threonine, and tyrosine residues of substrate proteins by protein kinases is probably ubiquitous cellular mechanism for regulation of physiological processes. It is known to us that most signaling pathways impinge at some point on protein kinases. Here we report a human putative receptor protein kinase cDNA STYK1. The STYK1 cDNA is 2749 base pairs in length and contains an open reading frame encoding 422 amino acids. The STYK1 gene is mapped to human chromosome 12p13 and 11 exons were found. RT-PCR showed that STYK1 is widely expressed in human tissues.

Amino Acid Sequence↗
PubMed2003

Cloning and sequence analysis of the human cDNA encoding the synaptoporin (delta), a highly conservative synaptic vesicle protein.

Synaptoporin is a membrane protein of synaptic vesicles, which belongs to the synaptophysin family. It was first isolated from rat brain. Here we report the cloning and characterization of the human cDNA that encodes the human homologue of synaptoporin. It has two splicing variants, which is in accordance with its ortholog in chicken. Its deduced amino acid sequence displays 97% and 81% identity with the synaptoporin of rat and chicken, respectively. This gene was mapped to the chromosome 3p14.3 by matching against the Human Genome Sequence Database. 16-tissue RT-PCR analysis shows that human synaptoporin is specifically expressed in the brain.

Amino Acid Sequence↗
PubMed2003

Cloning and identification of a novel human RNPC3 gene that encodes a protein with two RRM domains and is expressed in the cell nucleus.

The RNA recognition motifs (RRM) domain is one of the most common eukaryotic protein folds. Proteins containing RRM domains function in important steps of posttranscriptional regulation of gene expression and are involved in processing and transport of mRNA precursors. Here we describe the cloning and characterization of a novel human RNPC3 gene containing two RNA recognition motifs. The 1870 bp cDNA encodes a protein with 517 amino acids. It also contains two bipartite nuclear targeting sequences, which is important for nuclear targeting for proteins, especially those functioning in the cell nucleus. The GFP location of the RNPC3 gene product shows that this protein is located in the cell nucleus. RT-PCR reveals that it is abundantly expressed in kidney and pancreas.

Amino Acid Motifs↗
PubMed2003

Cloning and characterization of human synaptotagmin 10 gene.

Synaptotagmin (Syt) is a membrane protein family of secretory vesicles, abundant in neural and some endocrine cells. All the members of this family contain one transmembrane region and two conserved C2 domains. Here we reported a new human Syt 10 gene isolated when screening a human fetal brain cDNA library. This cDNA clone is 3287 bp and contains an open reading frame from 299 to 1870 encoding a putative protein of 523 amino acids. It shares 94.6 and 94.8% homology to rat Syt 10 and mouse Syt 10 at protein level, respectively. RT-PCR result showed that it is expressed only in pancreas, lung and kidney.

Amino Acid Sequence↗
PubMed2003

Cloning and characterization of a novel splice variant of the brain-specific protein densin-180.

Densin-180 is a brain-specific synaptic protein of the o-sialoglycoprotein family. It functions in specific adhesion between presynaptic and postsynaptic membranes at glutamatergic synapses. We have cloned a novel splice variant of densin-180 from a fetal brain cDNA library and termed it LRRC7. It is located on 1p31 and consists of 8 exons. It encodes a putative protein of 216 amino acids which contains a nuclear localization signal and four leucine-rich repeats (LRRs). LRRs are 20-29 residue sequence motifs present in a number of proteins with diverse functions. Expression analysis of LRRC7 shows it is expressed ubiquitously while its splice variant densin-180 is brain-specific.

Alternative Splicing↗
PubMed2003

Transurethral electrochemical treatment of benign prostatic hyperplasia.

OBJECTIVE: To study the mechanism and feasibility of transurethral electrochemical therapy for the treatment of benign prostatic hyperplasia (BPH). METHODS: Between March 1998 and March 2000, specifically designed devices and catheters for electrochemical therapy were applied to 6 prostate specimens obtained by suprapubic prostatectomy in order to treat BPH patients with urinary retention for whom surgery was contraindicated. Sixteen patients (with a mean age of 77.3 years old) underwent electrical treatment totaling 160-220 coulombs under topical urethral anesthesia for 68-132 min. The catheters remained inside the patient for 7-10 d. RESULTS: Irreversible destructive changes occurred within cathodal tissue, while carbonization occurred within anodic tissue. The radius of tissue change was 7-8 mm and 1-2 mm, respectively. In vivo trial: 11 (69%) patients could be weaned off the catheters with satisfactory urination. Three months after therapy, the mean international prostate symptom score (IPSS) was 14.5, mean peak flow rate was 10.5 ml/s, and mean residual urine was 39 ml. No serious complications were observed. CONCLUSION: Transurethral electrochemical treatment is potentially a minimally invasive alternative for treatment of BPH, especially for elderly patients at high risk.

Aged↗
PubMed2003

[Expression and significance of clusterin in normal prostate, benign prostate hyperplasia and prostate cancer].

OBJECTIVE: To investigate the expression and significance of Clusterin in normal prostate, benign prostate hyperplasia (BPH) and prostate cancer. METHODS: Clusterin expression in samples of 12 normal prostate, 15 BPH, and 56 prostate cancer were studied by immunohistochemical stain. RESULTS: Of 83 cases, 67 are positive or weak positive (81%). The rate of positive or weak positive for normal prostate, BPH and prostate cancer was 17% (2/12), 73% (11/15), and 96% (54/56) respectively. The expression level of Clusterin in prostate cancer was much higher than in normal prostate (t = 8.82, P < 0.01). BPH (t = 7.63, P < 0.01) was related positively with pathological grade (r = 0.649, P < 0.01) and stage (r = 0.609, P < 0.01) of prostate cancer. CONCLUSION: Clusterin may play an important role in the biological characteristics of prostate cancer by the anti-apoptosis pathway.

Apoptosis↗
PubMed2003

[Multivariate analysis of recurrence in T1 bladder transitional cell carcinoma].

OBJECTIVE: To investigate the prognostic value of some clinicopathologic indexes and biologic tumor markers in predicting recurrence in T1 transitional cell carcinoma (TCC) of the bladder. METHODS: The expressions of p53, E-cadherin and VEGF of 75 patients with T1 primary bladder TCC were detected by streptabitin peroxidase (SP) immunohistochemical methods. The effects of clinicopathologic indexes and biologic tumor markers on recurrence were assessed by Kaplan-Meier and Cox proportional hazards model. RESULTS: The 1-, 3-, and 5-year recurrence- free survival rates were 68.0%, 45.3% and 20.9%. In Kaplan-Meier analysis, tumor mutifocality and the expression of p53, E-cadherin and VEGF were associated with recurrence. In multivariate analysis, the independent recurrence variables were tumor mutifocality, the expression of p53 and E-cadherin. CONCLUSION: Tumor mutifocality and the abnormal expression of p53 and E-cadherin are the variables that independently predict recurrence in T1 transitional cell carcinoma of the bladder.

Adult↗
PubMed2003

[Impact of short-term neoadjuvant hormonal treatment on neuroendocrine differentiation in prostate carcinoma].

OBJECTIVE: To study the impact of short-term neoadjuvant hormonal treatment on neuroendocrine (NE) differentiation and the relation of NE differentiation and tumor regression. METHODS: The radical prostatectomy specimens and the biopsy specimens of the same 18 patients with prostate cancer were compared. The effect of hormonal treatment on NE-differentiation was evaluated by specific antibodies against chromogranin A (ChA) and serotonin (5-HT). RESULTS: The ChA-positive cell count was 3.2 x 10(-5)/microm(2) [(0-5.7) x 10(-5)/microm(2)] before hormonal treatment and 2.3 x 10(-5) microm(2)[(0-6.6) x 10(-5)/microm(2)] afterward (P > 0.05). For the proportion of NE-positive tumor, it was 7.0% (0%-14.9%) and 4.5% (0%-13.1%) (P > 0.05). No correlation existed between NE-differentiation and the neoadjuvant hormonal treatment. The NE cell density did not differ significantly between 12 non-/slightly regressive tumor foci and 6 highly regressive ones (P > 0.05). CONCLUSION: Short-term neoadjuvant hormonal therapy does not induce clonal propagation of NE cells. The degree of tumor regression following short-term neoadjuvant hormonal therapy is not correlated with the NE differentiation.

Aged↗
PubMed2003

[Application of atomic force microscopy in the study of morphology of double minute chromosomes].

Atomic force microscopy (AFM) has many advantages in the study of biological samples, such as the convenient specimen preparation and the high resolution. In the present study, AFM was used to observe the double minute chromosomes (DMs) in mouse methotrexate-resistant cell line 3T3R500. AFM images were obtained by tapping mode, contact mode and later force mode of AFM. DMs were composed of two compact spheres connected with fibers. The number of DMs in the 3T3R500 cells increased with increasing levels of methotrexate (MTX) resistance. The data of the height and the underside diameter of the DMs were also obtained. The details of specimen preparation and scan mode selection of AFM were discussed. Our results show that AFM is a powerful method in the study of DMs.

Animals↗