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Biomedical subjects

Li Zeng

Publications and source records attributed to Li Zeng.

At least 37 records · Page 2Linked to original sources
PubMed2005

Neurological monitoring and off-pump surgery in a very high-risk stroke patient.

Stroke remains a high risk of coronary artery bypass grafting. We present a patient with progressively symptomatic coronary disease and severe four-vessel cerebrovascular disease not amenable to revascularization. This patient underwent coronary revascularization without neurologic complication using off-pump coronary surgery to avoid aortic manipulation and intraoperative electroencephalographic monitoring of cerebral perfusion. This management strategy may reduce the stroke risk in similar patients.

Coronary Artery Bypass, Off-Pump↗
PubMed2005

Effect of terazosin on tissue vascularity and apoptosis in transitional cell carcinoma of bladder.

OBJECTIVES: To present a pilot study to determine whether the alpha1-adrenoceptor antagonist terazosin can induce apoptosis in transitional cell carcinoma (TCC) of the bladder, similar to the effect seen with prostate cancer. The alpha1-adrenoceptor antagonist terazosin has recently been shown to induce apoptosis in prostate cancer cells both in vitro and in vivo and to reduce prostatic tissue vascularity by potentially affecting endothelial cell adhesion. METHODS: The records of 24 men who underwent radical cystectomy for TCC of the bladder at the Lexington Veterans Affairs Medical Center were reviewed. The control group consisted of 15 men who were never exposed to terazosin. The study group consisted of 9 men who were treated with terazosin before cystectomy. Sections of the bladder tumor and normal trigone were subjected to immunohistochemical analysis for microvessel density, endothelial cell CD31 expression, and apoptosis detection (terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labeling), as well as high-molecular-weight cytokeratin staining. RESULTS: A significant reduction in tissue vascularity (14.0 versus 19.2, P <0.05) and a significant increase in the apoptotic index (3.0% versus 1.7%, P <0.05) was detected in terazosin-treated bladder tumors compared with untreated bladder tumors. Most TCC specimens (80%) exhibited strong and consistently uniform immunostaining for high-molecular-weight cytokeratin staining. CONCLUSIONS: These results suggest that terazosin reduces tumor vascularity and induces apoptosis in TCC of the bladder. Additional studies with more patients are necessary to reach definitive conclusions. However, considering the proven apoptotic action of terazosin in prostatic tissue, this study may have implications for the use of terazosin in the treatment of bladder TCC.

Adrenergic alpha-Antagonists↗
PubMed2005

[Expression of IRP2 mRNA, TfR mRNA and Fn mRNA in HL-60 cells].

To explore the mechanism of iron metabolism and its regulation as well as the roles of IRP(2) in ion metabolism of HL-60 cells, HL-60 cells were cultured in RPMI 1640 medium supplemented with 10% heat-inactivated fetal bovine serum, which was treated with ferric chloride (FeCl(3)) or deferoxamine (DFO). The cells were harvested at 12, 24 and 48 hours of proliferation, and total RNA was isolated; cDNA was synthesized by reverse transcription (RT), and relative expression levels of IRP(2) mRNA, Fn mRNA and TfR mRNA were determined by RT-PCR. The results showed at follows: (1) the level of IRP(2) mRNA remained constant in all cells, whether or not treated with DFO or FeCl(3). However, the expression of IRP(2) mRNA decreased when the time of cell culture was prolonged. There was no significant difference between groups (F(B-S) = 1.199, P > 0.05), but there was significant difference among the different time culture (F(W-S) = 43.418, P < 0.01). (2) Cells which treated neither with DFO nor ferri chloride showed significant difference from the control (F(W-S) = 7.184, F(B-S) = 113.926; P < 0.01). The level of TfR mRNA increased in the cells treated with DFO. Surprisingly, when cells treated with FeCl(3), there was not decline of TfR mRNA expression, but it increased lightly at 12 hours and peaked at 24 hours and declined drastically at 48 hours. (3) The level of Fn mRNA in the cells treated with FeCl(3) was approximately 2-fold as the control cells. In contrast with the control cells, there was significant difference (P < 0.05). The level of Fn mRNA of the cells treated with DFO had little change. As compared with the control cells, no significant difference was seen (P > 0.05). (4) There was not any significant correlation between IRP(2) mRNA and TfR mRNA or Fn mRNA in HL-60 cells (r = -0.005; r = 0.074; P > 0.05). It is concluded that (1) IRP(2) may regulate the iron metabolism in HL-60 cells by altering amounts of the IRP(2) 3.7- or 6.4-kb mRNA at the transcriptional level, or by IRP(2) degradation at the post transcriptional level. (2) Both of Fn mRNA and TfR mRNA participated, more or less, in the iron metabolism in HL-60 cells.

Ferritins↗
PubMed2004

Donor ligand effect on the nature of the oxygenating species in Mn(III)(salen)-catalyzed epoxidation of olefins: experimental evidence for multiple active oxidants.

The stereoselectivity of olefin epoxidation catalyzed by Mn(III)(salen)X (1a, X = Cl(-); 1b, X = BF(4)(-)) complexes is examined in the presence of neutral donor ligands, employing various iodosylarenes (ArIO: PhIO, C(6)F(5)IO, and MesIO) as the oxygen atom source. The cis/trans ratios of stilbene oxides and the enantiomeric excesses of styrene oxide and 1,2-dihydronaphthalene oxide are found to be strongly dependent on the nature of the iodosylarenes under certain conditions. In other cases, olefin epoxidation is shown to proceed with essentially identical diastereoselectivities or enantioselectivities, regardless of the oxygen atom source used. We propose that a Mn(V)(salen)-oxo intermediate and a complex between the catalyst and the terminal oxidant competitively effect the epoxidation when the stereoselectivities are markedly dependent on the oxygen atom source. A single Mn(V)(salen)-oxo species is considered to be the sole oxygenating intermediate when the terminal oxidants do not exert a notable influence on the product selectivities. Our results clearly demonstrate the existence of multiple oxidizing species and the conditions in which only a single oxygenating intermediate is involved. The axial donor ligands (both anionic ligands and neutral ligands) are shown to strongly influence both the identity and the reactivity of the oxygenating species.

Journal Article↗
PubMed2004

Enhanced stimulation of chromosomal translocations by radiomimetic DNA damaging agents and camptothecin in Saccharomyces cerevisiae rad9 checkpoint mutants.

Saccharomyces cerevisiae rad9 checkpoint mutants exhibit pleiotropic phenotypes, including higher frequencies of chromosome loss, radiation sensitivity, and decreased induction of DNA damage-inducible genes. We had previously shown that rad9 mutants exhibit higher frequencies of DNA damage-associated translocations but lower frequencies of DNA damage-associated sister chromatid exchange (SCE), compared to wild type. Herein, we have shown that differences between the frequencies of DNA damage-associated recombination in the rad9 mutant and wild type depend on the identity and the concentration of the DNA damaging agent. Translocation and SCE frequencies were measured in strains containing truncated his3 fragments, located either on chromosomes II and IV, or located in tandem on chromosome IV, respectively. DNA damage-associated frequencies of translocations after exposure to hydrogen peroxide (H(2)O(2)), bleomycin, phleomycin, cisplatin, and camptothecin are higher in the rad9 diploid than in wild type. However, translocation frequencies after exposure to 4-nitroquinoline 1-oxide (4-NQO) and N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) are similar in rad9 and wild-type strains. We suggest that the deficiency in triggering G(2) arrest after exposure to specific DNA damaging agents results in the higher levels of DNA damage-associated translocations in rad9 mutants.

4-Nitroquinoline-1-oxide↗
PubMed2004

Conditional macrophage ablation in transgenic mice expressing a Fas-based suicide gene.

Transgenic mice expressing an inducible suicide gene, which allows systemic and reversible elimination of macrophages, were developed. A macrophage-specific c-fms promoter was used to express enhanced green fluorescent protein and a drug-inducible suicide gene that leads to Fas-mediated apoptosis in resting and cycling cells of the macrophage lineage. Transgenic mice were fertile, of normal weight, and showed no abnormal phenotype before drug exposure. The transgene was expressed constitutively in macrophages and dendritic cells (DC) but not significantly in T cells or B cells. Induction of the suicide gene led to depletion of 70-95% of macrophages and DC in nearly all tissues examined. Depletion reduced the ability to clear bacteria from the blood and led to increased bacterial growth in the liver. Depleted mice displayed several abnormalities, including splenomegaly, lymphadenopathy, thymic atrophy, extramedullary hematopoiesis, and development of peritoneal adhesions. This new, transgenic line will be useful in investigating the role of macrophages and DC.

Animals↗
PubMed2004

Apoptosis incidence and protein expression of p53, TGF-beta receptor II, p27Kip1, and Smad4 in benign, premalignant, and malignant human prostate.

Deregulation of apoptosis is involved in prostate cancer development and progression. This study involved an immunohistochemical "profiling" of prostate tissue specimens from patients who underwent prostatectomy for localized prostate cancer, to identify apoptosis-specific alterations associated with premalignant precursor lesions. Prostate tissue was pathologically evaluated, and areas of benign acini, high-grade prostate intraepithelial neoplasia (HGPIN), and prostate cancer were identified. Immunohistochemical analysis was performed to determine the expression of p27Kip1, a key cell cycle regulator, transforming growth factor (TGF)-beta receptor II (TbetaRII), a critical signaling effector of TGF-beta; Smad4, a downstream intracellular effector of TGF-beta signaling; p53, a key apoptosis regulator; and prostate-specific antigen (PSA), a clinical marker of prostate cancer. The apoptotic index of the same cell populations was determined using the transferase-mediated digoxigenin-tagged 16-desoxy-uridine-triphosphate nick end labeling assay. Our findings indicate a significant reduction in p27Kip1 immunoreactivity in HGPIN (P<0.0001) and prostate cancer (P<0.0001) compared with the benign tissue. A significant down-regulation was detected in TbetaRII expression in HGPIN and prostate cancer compared with benign prostatic hyperplasia (BPH)(P<0.001). A significant decrease was also observed in Smad4 levels in HGPIN and prostate cancer compared with BPH (P<0.001). Evaluation of the incidence of apoptosis revealed a significant decrease in the apoptotic index among the epithelial cell populations in HGPIN and a further decrease in prostate carcinoma (P<0.01). This reduced apoptotic index correlated with a significant increase in p53 immunoreactivity in the prostatic carcinoma foci. Prostate cancer cells exhibited strong nuclear staining for p53 compared with adjacent HGPIN (P<0.05) and the benign lesions of the same prostate specimens (P<0.05). A significant reduction in PSA immunostaining was detected in HGPIN and prostate carcinoma foci compared with the benign glandular epithelia (P<0.001). These results further define deregulation of TGF-beta signaling effectors as a molecular basis for loss of apoptotic control contributing to the development of prostate tumors. Identification of apoptotic regulators in precursor premalignant lesions may have prognostic significance in disease progression as well as therapeutic value for targeting prostate cancer.

Adenocarcinoma↗
PubMed2004

cDNA cloning and expression analysis of a novel human F-box domain containing gene.

F-box proteins are a large family of eukaryotic proteins that are characterized by an approximately 40 amino acid motif. Some F-box proteins are critical for the controlled degradation of cellular regulatory proteins. Here we report that a novel member of F-box proteins, FBXO35 gene, was cloned and identified during the large-scale sequencing analysis from a human fetal brain cDNA library. FBXO35 gene shares amino acid similarity with several putative mouse genes not only in F-box domain but also in the rest of the sequence, which indicates that FBXO35 might also contain some other unknown conserved domain. RT-PCR analysis indicated that FBXO35 gene had a ubiquitously low expression pattern in most human adult tissues. According to bioinformatics analysis, the FBXO35 gene was found located in chromosome 3p21.

Amino Acid Sequence↗
PubMed2004

Characterization of a human Sec14-like protein cDNA SEC14L3 highly homologous to human SPF/TAP.

Supernatant protein factor (SPF) and alpha-tocopherol-associated protein (TAP) both belong to a widespread lipid-binding Sec 14-like protein family. All the members of the family have the lipid-binding motif called CRAL_TRIO. SPF is showed to stimulate the conversion of squalene to lanosterol and enhance cholesterol biosynthesis. TAP is identified to be involved in the intracellular distribution of alpha-tocopherol. Recently TAP is identified as SPF though they have very different functions. Here we report a human SPF/TAP homology SEC14L3 with 2082 base pairs in length and contains an open reading frame encoding a 400 amino acids protein. Analysis shows that SEC14L3 is mapped to 22q12 and expresses only in the liver among the used sixteen tissues in the test.

ATP-Binding Cassette Transporters↗
PubMed2004

Cloning and characterization of a human cDNA ACAD10 mapped to chromosome 12q24.1.

Mitochondrial fatty acid beta-oxidation is an important energy resource for many mammal tissues. Acyl-CoA dehydrogenases (ACADs) are a family of flavoproteins that are involved in the beta-oxidation of the fatty acyl-CoA derivatives. Deficiency of these ACADs can cause metabolic disorders including muscle fatigue, hypoglycaemia, hepatic lipidosis and so on. By large scale sequencing, we identified a cDNA sequence of 3960 base pairs with a typical acyl-CoA dehydrogenase function domain. RT-PCR result shows that it is widely expressed in human tissues, especially high in liver, kidney, pancreas and spleen. It is hypothesized that this is a novel member of ACADs family.

Acyl-CoA Dehydrogenase↗
PubMed2004

Cloning and expression of human GTDC1 gene (glycosyltransferase-like domain containing 1) from human fetal library.

The glycosyltransferases (GTs) catalyze the synthesis of the carbohydrate portions of glycoproteins, glycolipids, and proteoglycans. Here we report the cloning and characterization of a novel human GTDC1 (glycosyltransferase-like domain containing 1) gene, which locates on human chromosome 2q22. The GTDC1 cDNA is 2954 bp in length, encoding a putative protein of 458 amino acids. At protein level human GTDC1 has 75 and 37% identity with its homologous counterparts in the mouse and fruitfly, respectively. RT-PCR analysis revealed its relatively high expression level in the adult lung, spleen, testis, and peripheral blood leukocyte.

Amino Acid Sequence↗
PubMed2004

[Report of a case of penile epithelioid sarcoma].

OBJECTIVE: To enhance the knowledge and the effect of the diagnosis and treatment of primary epithelioid sarcoma of the penis. METHODS: One rare case of primary epithelioid sarcoma of the penis was studied with regard to its primary clinical process and characteristics, differential diagnosis and method of treatment. RESULTS: An operation was performed on the penis to treat the epithelioid sarcoma. The diagnosis was confirmed by immunohistological and pathological techniques. There was no evidence of relapse during the three-year follow-up after operation. CONCLUSION: The possibility of primary epithelioid sarcoma of the penis should be considered if a mass or induration of the proximal penis and the symptoms of urethremphraxis are found. Total phallectomy could be chosen as an appropriate method of treatment. Unless adenopathy is palpable, node dissections are not recommended.

Adult↗
PubMed2004

cDNA cloning, gene organization and expression analysis of human peptidylarginine deiminase type VI.

Peptidylarginine deiminase (PAD) catalyzes the post-translational modification of protein through the conversion of arginine to citrulline in the presence of calcium ions. Human, similar to rodents, has four isoforms of PAD (type I, II, III and IV/V), each of which is distinct in substrate specificity and tissue specific expression. In our large-scale sequencing project, we identified a new human PAD cDNA from a human fetal brain cDNA library. The putative protein encoded by this cDNA is designated hPADVI. Expression analysis of hPADVI showed that it is mainly expressed in adult human ovary and peripheral blood leukocytes. We conclude that hPADVI may be orthologous to mouse ePAD, basing on sequence comparison, chromosome localization and exon-intron structure analysis. PAD-mediated deimination of epithelial cell keratin resulting in cytoskeletal remodeling suggests a possible role for hPADVI in cytoskeletal reorganization in the egg and in early embryo development. This study describes a new important member of the human PAD family.

Amino Acid Sequence↗
PubMed2004

[Effect of heparin on fetal growth restriction].

OBJECTIVE: To investigate the clinical effect and safety of heparin in treating fetal growth restriction (FGR). METHODS: A total of 107 women diagnosed with FGR were randomized into three groups. Group 1 (standard heparin group, n = 37) received 50 - 75 mg standard heparin added to 500 ml 5% glucose sodium chloride, infused intravenously in 6 - 8 hours. Group 2 (low molecular weight heparin group, n = 31) received 0.2 - 0.4 ml low molecular weight heparin given by subcutaneous injection. Control group (n = 39) received 20 ml dan-shen added to 500 ml low-molecular-weight dextran infused intravenously. Fetal growth indices, biophysical score, umbilical artery blood flow, count of platelet (PLT), prothrombin time (PT), activated partial thromboplastin time (APTT), 1-minute Apgar score, body weight and gestational age of the neonates were measured. Babies prognosis was followed-up. RESULTS: (1) Height of fundus of uterus was obviously increased per week in the groups of standard heparin (0.7 +/- 0.6) cm and low molecular weight heparin [(0.7 +/- 0.6) cm]] vs. control group [(0.5 +/- 0.4) cm, P < 0.05]. Biparietal diameter of fetus increased in standard heparin [(2.4 +/- 0.7) mm] and low molecular weight heparin [(2.5 +/- 0.8) mm] groups vs. control [(1.7 +/- 0.6) mm, P < 0.05]. The femur length, head circumference and abdominal circumference of fetus were significantly longer in heparin treated patients than in control group (P < 0.05). (2) Biophysical score improved in groups of standard heparin (9.7 +/- 0.8) and low molecular weight heparin (9.6 +/- 0.6) vs. control group (8.9 +/- 0.7) (P < 0.05). (3) Umbilical blood S/D ratio decreased in standard heparin (2.5 +/- 0.5) and low molecular weight heparin (2.4 +/- 0.5) groups vs. control group (2.9 +/- 0.6) (P < 0.05). Pulsatile index (PI) and resistance index (RI) were significantly lower also (P < 0.05).(4) Rate of one minute Apgar score (8 - 10) was 86% in group 1, 87% in group 2 and 74% in control group, respectively. Body weight of the neonates was significantly increased in group 1(3100 +/- 256 g) and in group 2 [(3080 +/- 225) g] vs. [(2580 +/- 304) g] in control group (P < 0.05). Gestational age was prolonged in group 1 [(38 +/- 3) w] and group 2 [(38 +/- 4) w] vs. control group [(37 +/- 4) w, P < 0.05]. (5) Incidence of term small for gestational age infant in groups of standard heparin and low molecular weight heparin was 5% and 6%, respectively, significantly lower than those in the control group (18%) (P < 0.05). (6) No difference was shown in PLT, PT and APTT before and after heparin treatment (P > 0.05). (7) There was no difference in fetal growth indices, biophysical score, umbilical blood, neonatal outcome between standard heparin and low molecular heparin groups. CONCLUSIONS: Heparin can improve placenta function and obviously increase body weight of fetuses and neonates. It is safe for both pregnant women and their fetuses.

Birth Weight↗
PubMed2003

Nogo-A at CNS paranodes is a ligand of Caspr: possible regulation of K(+) channel localization.

We report Nogo-A as an oligodendroglial component congregating and interacting with the Caspr-F3 complex at paranodes. However, its receptor Nogo-66 receptor (NgR) does not segregate to specific axonal domains. CHO cells cotransfected with Caspr and F3, but not with F3 alone, bound specifically to substrates coated with Nogo-66 peptide and GST-Nogo-66. Binding persisted even after phosphatidylinositol- specific phospholipase C (PI-PLC) removal of GPI-linked F3 from the cell surface, suggesting a direct interaction between Nogo-66 and Caspr. Both Nogo-A and Caspr co-immunoprecipitated with Kv1.1 and Kv1.2, and the developmental expression pattern of both paralleled compared with Kv1.1, implicating a transient interaction between Nogo-A-Caspr and K(+) channels at early stages of myelination. In pathological models that display paranodal junctional defects (EAE rats, and Shiverer and CGT(-/-) mice), distances between the paired labeling of K(+) channels were shortened significantly and their localization shifted toward paranodes, while paranodal Nogo-A congregation was markedly reduced. Our results demonstrate that Nogo-A interacts in trans with axonal Caspr at CNS paranodes, an interaction that may have a role in modulating axon-glial junction architecture and possibly K(+)-channel localization during development.

Amino Acid Sequence↗
PubMed2003

Development of new multivalent-bispecific agents for pretargeting tumor localization and therapy.

PURPOSE: Two bispecific diabodies (BS1.5 and BS1.5H) and two bispecific trivalent proteins (BS6 and BS8) were produced and tested as potential agents for pretargeted delivery of radiolabeled bivalent haptens to tumors expressing carcinoembryonic antigen. EXPERIMENTAL DESIGN: Each of the four proteins was expressed in Escherichia coli and purified from the soluble fraction. BS1.5 and BS1.5H (a humanized version of BS1.5) were evaluated in the GW-39 human colonic tumor-nude mouse model using a di-HSG-1,4,7,10-tetra-azacyclododecane-N,N',N" N"'-tetraacetic acid peptide (IMP-241) radiolabeled with (111)In. The biodistribution and T/NT ratios were compared with those of hMN-14 x m679 (Fab' x Fab') prepared chemically. RESULTS: In animals, both BS1.5 and BS1.5H cleared more rapidly than hMN-14 x m679 and showed tumor to nontumor ratios far superior to those of hMN-14 x m679. For example, with BS1.5 injected 8 h before (111)In-IMP-241, the tumor uptake of (111)In was 10.3 +/- 2.7 and 6.3 +/- 2.2% ID/g at 3 and 24 h, respectively, with the tumor to blood ratios being 167 +/- 35 at 3 h and 631 +/- 231 at 24 h. In comparison, the tumor to blood ratios of (111)In observed for hMN-14 x m679 given 24 h earlier were 8 +/- 2 at 3 h and 16 +/- 3 at 24 h. CONCLUSIONS: These results indicate that BS1.5 and BS1.5H are promising candidates for use in a variety of pretargeting applications, including tumor therapy with radionuclides and drugs. BS6 and BS8 may be even more attractive because of their potential to achieve higher levels of tumor uptake because of divalent carcinoembryonic antigen binding.

Animals↗