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Biomedical subjects

Jian Zhang

Publications and source records attributed to Jian Zhang.

At least 145 records · Page 8Linked to original sources
PubMed2006

[The value of multislice spiral CT in the diagnosis and staging of laryngeal carcinoma].

OBJECTIVE: To our knowledge, no date are available comparing the impact of multislice spiral CT, and multiplanar reconstruction (MPR) and Virtual endoscopy (VE) on pretherapeutic staging accuracy. The purpose of our study was to determine which imaging should be used as an adjunct to other clinical examinations in the pretherapeutic diagnosis and staging of laryngeal carcinoma. METHOD: Thirty-two patients with laryngeal carcinoma who were treated surgically, were prospectively underwent by contrast-enhanced multislice spiral CT, and MPR and VE were subsequently done. CT slice thickness 5 mm, table feed was 5 mm, and 100 ml of intravenous contrast material was administered at a flow of 3.0 ml/s. Two radiologists evaluated axial image and the combined image, the results were studied in a blind way. UICCTNM stages were determined by the axial image findings and the combined image findings of axial image, MPR, and VE, were compared and correlated with postoperative pathology and microlaryngoscopy. RESULT: In the evaluation of the neoplastic invasion of ventricular fold, vocal cord, the anterior commissure, subglottic region,paraglottic space (PGS), pre-epiglottic space (PES), thyroid cartilage, and tissue beyond the larynx, the combined images were better than axial images in accuracy (98.3% vs 91.3%, P < 0.01); The accuracy of the combined images staging was 81.3% and the accuracy of axial image staging was 93.8%, the difference was not statistically significant (P > 0.05). CONCLUSION: Axial image combined with subsequent MPR and VE could improve the diagnosis in the evaluation of the neoplastic invasion, neither axial image or the combined images could significantly improve pretherapeutic staging of laryngeal carcinoma.

Adult↗
PubMed2006

[Inhibition of serine/threonine kinase 15 gene expression induces apoptosis of gastric cancer cells].

OBJECTIVE: To observe the effect of inhibition of serine/threonine kinase15 (STK15) gene expression on apoptosis induction in gastric cancer cell line-MKN45 and discuss the role of STK15 in viability of gastric cancer cells. METHODS: The STK15 expression was inhibited by chemically synthesized siRNA. The STK15 mRNA and protein level were respectively measured by real-time quantitative PCR and western blotting,the change of cell cycle distribution and apoptosis rate were detected by flow-cytometry, cell morphological change was observed by Hoechst staining,and pro-caspase 3 level was also detected by western blot. RESULTS: After treatment by siRNA targeting STK15 after 48 h, STK15 mRNA and protein level decreased obviously. More MKN45 cells accumulated at G(2)/M phase (P< 0.05). The apoptosis rate of STK15 siRNA treated MKN45 cells was higher than that of control cells(P< 0.05) with the pro-caspase 3 level decreased. CONCLUSIONS: Inhibition of STK15 gene expression may induce apoptosis in MKN45 cells through the pathway of caspase3. STK15 gene play a key role in proliferation and viability of MKN45 cells.

Apoptosis↗
PubMed2006

[Biomechanical evaluation of anterior cervical spine stabilization with step-cut grafting and absorbable screw fixation].

OBJECTIVE: To determine the initial stability of a novel construct in cadaveric cervical spine in comparison with a conventional method. METHODS: Twelve specimens of fresh human cadaveric cervical spines (C(3)-C(7)) were randomly divided into the test group and control group. In the former group, one-level corpectomy of C(5) and three cortical iliac step-cut grafting with absorbable screw fixation was performed, and one-level corpectomy of C(5) and three cortical iliac strut grafting with anterior plate fixation in the control group. Flexibility test and graft push of strength test were carried out before and after grafting and fixation to determine the range of motion (ROM), neutral zone (NZ) and graft push out strength (POS). RESULTS: The cervical spines of the two groups all had increased initial stability in all 6 rotational degrees of freedom with also enhanced graft POS after fixation. Compared with the control group, the test group had higher stability in extension and comparable stability in flexion and axial rotation, but lower stability in lateral bending. The graft POS after fixation in the test group, however, was lowered in comparison with the control group. CONCLUSION: Step-cut grafting and absorbable screw fixation provides sufficient stability potential for the cervical spine in vitro and allows optimum biomechanical and biological environments to enhance graft fusion and reduce complications.

Absorbable Implants↗
PubMed2006

[The correlation of PDGF and TNF-alpha and HA and nasal mucosa healing after ESS].

OBJECTIVE: To investigate the relation of healing outcomes and three factors in nasal fluid before and after endoscopic sinus surgery (ESS), including platelet derived growth factor (PDGF), tumour necrosis factor-alpha (TNF-alpha) and hyaluronic acid (HA). METHOD: We compared the amounts of PDGF, TNF-alpha, HA among the three stages in 22 patients operated for nasal polyposis. The concentrations of PDGF, TNF-alpha, HA were compared before and after operation between good healing and poor healing at 12th week, and gender, age, body mass, preoperative stage were also compared. Finally, we performed a multiple logistic regression model to assess whether the healing quality was associated with gender, age, body mass, preoperative stage, and concentrations of PDGF, TNF-alpha, HA before ESS. RESULT: (1) A significant difference in the concentrations of PDGF and HA could be demonstrated between the first and second stage, or between the first and third stage. But there was no difference in TNF-alpha among three stages. (2) The healing quality after ESS was significantly and independently correlated to the age of patient and preoperative PDGF concentrations in nasal secretions, the younger, the better healing. The lower PDGF concentration, the better healing, and vice versa. CONCLUSION: During the wound healing of nasal mucosa, the levels of PDGF, TNF-alpha, HA are different at each postoperative stage. Age and PDGF concentrations preoperatively are suitable factors to predict the healing quality after ESS.

Adolescent↗
PubMed2006

[Treatment performance and enhancement of subsurface constructed wetland treating polluted river water in winter].

Treatment performance of subsurface constructed wetland treating polluted river water in winter was studied. When hydraulic loading fell down from 30cm/d to 15cm/d, the average removal rates of ammonium nitrogen and COD rose up from 14% and 20% to 39% and 31% respectively. Water temperature had great influence on ammonium nitrogen removal. Membrane overlay on the wetland could improve pollutants removal efficiently. The average removal rates of ammonium nitrogen and COD could rise up from 29.4% and 29% to 67.6% and 46.6% respectively. Microorganism enzyme activity experiments show that increase of microorganism activity caused by membrane overlay contributed a lot to pollutants removal enhancement. Urease activity rose up from 0.025 mg/(g x d) to 0.037 mg/(g x d) with membrane overlay, and dehydrogenase activity rose up from 0.17 microL/(d x g) to 4.54 microL/(d x g) with membrane overlay. The pollutants releasing experiment of aquatic plants show that faded plants would release a lot of pollutants into water. Therefore, plants harvest was necessary in autumn.

Ammonia↗
PubMed2006

[Sustainable operation of subsurface constructed wetland treating polluted river water].

Water quality, flux and temperature of polluted river in northern China fluctuate a lot in a year around, which is disadvantageous for sustainable operation of subsurface constructed wetland treating polluted river water. A pilot system of subsurface constructed wetland treating polluted river water was operated for one year to study the sustainable operation of the process. The results show that ammonia removal performance fluctuated a lot according to different seasons. At the hydraulic loading of 15 cm/d, ammonia nitrogen removal rates were above 70% in summer, however, below 30% in winter when water temperature was below 15 degrees C. Changes of water temperature had little influence on COD removal performance. In the wet season of summer, the pilot wetland system could bear a short-period flood hydraulic loading, and ammonia nitrogen and COD removal rates were 52% and 36% respectively at the hydraulic loading of 100 cm/d. The activity of soil dehydrogenase had a positive correlation with seasonal changes of temperature and pollution removal performance.

Ammonia↗
PubMed2006

[A clinical study on implantation of autologous bone marrow mononuclear cells after bone marrow stimulation for treatment of lower limb ischemia].

OBJECTIVE: To observe the clinical efficiency of the implantation of the autologous bone marrow mononuclear cells for treatment of lower limb ischemia after the bone marrow stimulation. METHODS: From May to December 2005, 43 ischemic limbs in 35 patients (23 males, 12 females; aged 34-90 years,averaged 71.3 year) were treated. Of the 35 patients, 30 had diabetic lower limb ischemia with 38 lower ischemic limbs, 2 had atherosclerosis obliterans with 2 ischemic lower limbs, and 3 had thromboangiitis obliterans with 3 ischemic lower limbs. Five patients with 5 ischemic limbs were in stage I lower limb ischemia (intermittent claudication), 15 patients with ischemic 19 limbs were in stage II (rest pain), 9 patients with 12 ischemic limbs were in stage IIIa (ulceration), and 6 patients with 7 ischemic lower limbs in stage IIIb (gangrene); 88.4% of all the ischemic lower limbs (38/43)had a pain, 79.1% (34/ 43) had coldness, and 69.8% (30/43) had limb numbness. The bone marrow of each patient was stimulated by an injection of the recombinant human granulocyte-macrophage colony-stimulatory factor (GSF), 300 microg/d for 2-3 days. The bone marrow 130-200 ml was drawn from the iliac spine and the mononuclear cells were obtained. Each patient received implantation of the autologous bone marrow mononuclear cells by an intramuscular injection, an arterial intraluminal injection or a combined injection of the two routes. RESULTS: The pain relief was found in 94.7% of the ischemic lower limbs, and pain improvement in 97.1% . Relieved numbness was found in 93.3%. The distance of the claudication was increased by all the ischemic limbs. An increase in the ankle/ brachial index (ABI) was found in 47.9%. The transcutaneous oxygen pressure (TcPO2) increased in 92.3%. The ulcer heal rate was 9.1% (1/11). Markedly-reduced ulcer wound was found in 27.3% (3/11). The amputation rate was 6.3% (3/48). Arterial angiography revealed that there was a new collateral vessel formation in 91.2%. Complications were as follows: fever and mild fatigue developed respectively in 1 patient after the bone marrow stimulation, but relieved by themselves. Acute but mild myocardial infarction was found in 1 patient with a slight precordial pain and elevation of myocardial enzymes 1 week after transplantation of the bone marrow mononuclear cells, but recovered after medical treatment. The follow-up averaged 5 months. According to the subjective criteria, the overall efficacy was 90%. ABI increased in 62.5% of the patients after operation and the value of TcPO2 was higher in 90% of the patients after this kind of therapy. Arterial angiography revealed a new collateral vessel formation in 90.5% of the 21 ischemic limbs. The foot ulcer healed in 7 and obviously improved in 3. Three of the foot ulcer patients were discharged 2-3 months after the amputation was performed on the diseased toes. CONCLUSION: Implantation of the autologous bone marrow mononuclear cells after the bone marrow stimulation of treatment of the lower limb ischemia has advantages of less marrow aspiration, more mononuclear cell content, satisfactory short-term effect, and relatively high safety. It is a new method of treating the lower limb ischemia besides the autologous bone marrow and peripheral blood mononuclear cell implantation. The long-term effect of this method needs a further study.

Adult↗
PubMed2006

[Experimental study on anti-tumor effect of extractive from Celastrus orbiculatus in vivo].

OBJECTIVE: To study the anti-tumor activity of extractive from Celastrus orbiculatus in vivo. METHOD: Mice bearing transplanted tumor S180 and Heps were used to study the effects of acetoacetate and n-butanol extractive from C. orbiculatus. The changes in serum contents of SOD and malondialdehyde (MDA) content were assayed. RESULT: Acetoacetate and n-butanol extractive from C. orbiculatus significantly inhibited the growth of S180 and Heps tumor in mice. SOD content was obviously increased, MDA content obviously decreased in the serum after extractive treatment. CONCLUSION: Acetoacetate and n-butanol extractive from C. orbiculatus have anti-tumor effects and anti-oxidative capacity.

Animals↗
PubMed2005

Involvement of COX-1 and up-regulated prostaglandin E synthases in phosphatidylserine liposome-induced prostaglandin E2 production by microglia.

After engulfment of apoptotic cells through phosphatidylserine (PS)-mediated recognition, microglia secrete prostaglandin E2 (PGE2), a potent anti-inflammatory molecule in the central nervous system. Despite the clinical significance, the mechanism underlying PGE2 production by phagocytosis of apoptotic cells is poorly understood. In the present study, we used PS liposomes to elucidate the phagocytic pathway for PGE2 production in microglia, because PS liposomes mimic the effects of apoptotic cells on microglia/macrophages. The level of PGE2 in the culture medium of primary cultured rat microglia was significantly increased by PS liposomes treatment but not by phosphatidylcholine liposomes treatment. The specific ligand for class B scavenger receptor (SR-B), high density lipoprotein, significantly suppressed PS liposome-induced PGE2 production. PS liposomes were immediately phagocytosed by microglia and sorted to endosomes/lysosomes. Cyclooxygenase (COX)-2 and membrane-bound prostaglandin E synthase-1 (mPGES-1) were induced by treatment with lipopolysaccharide (LPS) but not with PS liposomes. On the other hand, mPGES-2 and cytosolic PGES (cPGES) that are functionally coupled with COX-1 were upregulated after treatment with PS liposomes or LPS. Furthermore, PS liposome-induced PGE2 production was significantly suppressed by indomethacin, a preferential COX-1 inhibitor, but not by NS-398, a selective COX-2 inhibitor. PS liposomes induced activation of p44/p42 extracellular signal-regulated kinase (ERK) but not p38 mitogen-activated protein kinase in SR-BI independent manner. These observations strongly suggest that the up-regulation of terminal PGESs that are preferentially coupled with COX-1, especially mPGES-2, plays the pivotal role in PS liposome-induced PGE2 production by microglia. Although SR-BI plays an essential role in PS liposome-induced PGE2 production, other PS-recognizing receptors, possibly PS-specific receptor, could also promote PGE2 production by transducing intracellular signals including p44/p42 ERK after PS liposomes treatment.

Animals↗
PubMed2005

Altered NMDA receptor trafficking contributes to sleep deprivation-induced hippocampal synaptic and cognitive impairments.

Recent evidence indicates that continuous wakefulness (sleep deprivation, SD) causes impairments in behavioral performance and hippocampal long-term potentiation (LTP) in animals. However, the mechanisms by which SD impairs long-term synaptic plasticity and cognitive function are not clear. Here, we report that 24-h SD in mice results in impaired hippocampus-dependent contextual memory and LTP and, unexpectedly, in reductions of the surface expression of NMDA receptor (NMDAR) subunit NR1 and NMDAR-mediated excitatory post-synaptic currents at hippocampal perforant path-dentate granule cell synapses. The results suggest that the reduction of functional NMDAR in hippocampal neurons may underlie the SD-induced deficits in hippocampus-dependent contextual memory and long-term synaptic plasticity.

Animals↗
PubMed2005

Significance of COX-2 expression in human esophageal squamous cell carcinoma.

Cyclooxygenase-2 (COX-2) is well established to play an important role in the tumorigenesis of a variety of human cancers; however, the function of COX-2 in the development of esophageal squamous cell carcinoma (ESCC) remains less clear. Here, we determined, first, the pattern of COX-2 expression in normal esophageal mucosa, dysplasia, carcinoma in situ (CIS) and invasive SCC. Immunohistochemical analysis showed that, while COX-2 was weakly expressed, if at all, in normal squamous epithelium, strong COX-2 expression was detected as early as the stage of dysplasia and frequently in 20 of 26 (77%) CIS and 86 of 111 (77%) invasive SCC. Upregulation of COX-2 in ESCC was found to be significantly associated with tumor progression (R = 0.493, P < 0.01). Further, treatment of human ESCC cell lines (KYSE450 and KYSE510) with NS-398, a COX-2 specific chemical inhibitor, suppressed the production of prostaglandin E2 (PGE2) and induced cell growth inhibition, cell cycle arrest at the G1-S checkpoint, and the expression of cyclin-dependent kinase inhibitors p21waf1/cip1 and p27kip1. Finally, knockdown expression of COX-2 in KYSE450 cells by a specific COX-2 siRNA dramatically inhibited PGE2 production, cell growth and, more importantly, colony formation and tumorigenesis in nude mice. Together, this study suggested that COX-2 may be involved in an early stage of squamous cell carcinogenesis of the esophagus and has a non-redundant role in the regulation of cellular proliferation and tumorigenesis of esophageal epithelial cells.

Animals↗
PubMed2005

Vascular endothelial growth factor contributes to prostate cancer-mediated osteoblastic activity.

Prostate cancer frequently metastasizes to bone resulting in the formation of osteoblastic metastases through unknown mechanisms. Vascular endothelial growth factor (VEGF) has been shown recently to promote osteoblast activity. Accordingly, we tested if VEGF contributes to the ability of prostate cancer to induce osteoblast activity. PC-3, LNCaP, and C4-2B prostate cancer cell lines expressed both VEGF-165 and VEGF-189 mRNA isoforms and VEGF protein. Prostate cancer cells expressed the mRNA for VEGF receptor (VEGFR) neuropilin-1 but not the VEGFRs Flt-1 or KDR. In contrast, mouse pre-osteoblastic cells (MC3T3-E1) expressed Flt-1 and neuropilin-1 mRNA but not KDR. PTK787, a VEGFR tyrosine kinase inhibitor, inhibited the proliferation of human microvascular endothelial cells but not prostate cancer proliferation in vitro. C4-2B conditioned medium induced osteoblast differentiation as measured by production of alkaline phosphatase and osteocalcin and mineralization of MC3T3-E1. PTK787 blocked the C4-2B conditioned medium-induced osteoblastic activity. VEGF directly induced alkaline phosphatase and osteocalcin but not mineralization of MC3T3-E1. These results suggest that VEGF induces initial differentiation of osteoblasts but requires other factors, present in C4-2B, to induce mineralization. To determine if VEGF influences the ability of prostate cancer to develop osteoblastic lesions, we injected C4-2B cells into the tibia of mice and, after the tumors grew for 6 weeks, administered PTK787 for 4 weeks. PTK787 decreased both intratibial tumor burden and C4-2B-induced osteoblastic activity as measured by bone mineral density and serum osteocalcin. These results show that VEGF contributes to prostate cancer-induced osteoblastic activity in vivo.

Alkaline Phosphatase↗
PubMed2005

Cloning, sequencing, analysis, and heterologous expression of the fredericamycin biosynthetic gene cluster from Streptomyces griseus.

Fredericamycin (FDM) A, a pentadecaketide featuring two sets of peri-hydroxy tricyclic aromatic moieties connected through a unique chiral spiro carbon center, exhibits potent cytotoxicity and has been studied as a new type of anticancer drug lead because of its novel molecular architecture. The fdm gene cluster was localized to 33-kb DNA segment of Streptomyces griseus ATCC 49344, and its involvement in FDM A biosynthesis was proven by gene inactivation, complementation, and heterologous expression experiments. The fdm cluster consists of 28 open reading frames (ORFs), encoding a type II polyketide synthase (PKS) and tailoring enzymes as well as several regulatory and resistance proteins. The FDM PKS features a KSalpha subunit with heretofore unseen tandem cysteines at its active site, a KSbeta subunit that is distinct phylogenetically from KSbeta of hexa-, octa-, or decaketide PKSs, and a dedicated phosphopantetheinyl transferase. Further study of the FDM PKS could provide new insight into how a type II PKS controls chain length in aromatic polyketide biosynthesis. The availability of the fdm genes, in vivo characterization of the fdm cluster in S. griseus, and heterologous expression of the fdm cluster in Streptomyces albus set the stage to investigate FDM A biosynthesis and engineer the FDM biosynthetic machinery for the production of novel FDM A analogues.

Antibiotics, Antineoplastic↗
PubMed2005

Discovering novel chemical inhibitors of human cyclophilin A: virtual screening, synthesis, and bioassay.

Cyclophilin A (CypA) is a member of cyclophilins, a family of the highly homologous peptidyl prolyl cis-trans isomerases (PPIases), which can bind to cyclosporin A (CsA). CypA plays critical roles in various biological processes, including protein folding, assembly, transportation, regulation of neuron growth, and HIV replication. The discovery of CypA inhibitor is now of a great special interest in the treatment of immunological disorders. In this study, a series of novel small molecular CypA inhibitors have been discovered by using structure-based virtual screening in conjunction with chemical synthesis and bioassay. The SPECS_1 database containing 85,000 small molecular compounds was searched by virtual screening against the crystal structure of human CypA. After SPR-based binding affinity assay, 15 compounds were found to show binding affinities to CypA at submicro-molar or micro-molar level (compounds 1-15). Seven compounds were selected as the starting point for the further structure modification in considering binding activity, synthesis difficulty, and structure similarity. We thus synthesized 40 new small molecular compounds (1-6, 15, 16a-q, 17a-d, and 18a-l), and four of which (compounds 16b, 16h, 16k, and 18g) showed high CypA PPIase inhibition activities with IC50s of 2.5-6.2 microM. Pharmacological assay indicated that these four compounds demonstrated somewhat inhibition activities against the proliferation of spleen cells.

Animals↗
PubMed2005

Upregulation of vascular inducible nitric oxide synthase mediates the hypotensive effect of ethanol in conscious female rats.

Previous reports from our laboratory have shown that ethanol elicits hypotension in female but not in male rats and that this effect of ethanol is estrogen dependent (El-Mass MM and Abdel-Rahman AA. Alcohol Clin Exp Res 23: 624-632, 1999; El-Mass MM and Abdel-Rahman AA. Clin Exp Hypertens 21: 1429-1445, 1999). In the present study, we tested the hypothesis that ethanol lowers blood pressure in female rats via upregulation of the inducible nitric oxide synthase (iNOS) in vascular tissues. The effects of pretreatment with NG-nitro-L-arginine (NOARG; nonselective nitric oxide synthase inhibitor) or aminoguanidine (selective iNOS inhibitor) on hemodynamic responses elicited by intragastric (ig) ethanol were determined in conscious female rats. Changes in vascular (aortic) iNOS protein expression evoked by ethanol in the presence and absence of aminoguanidine were also measured by immunohistochemistry. Compared with control (water treated) female rats, ethanol (1 g/kg ig) elicited hypotension that was associated with a significant increase in the aortic iNOS activity. The hypotensive effect of ethanol was virtually abolished in rats infused with the nitric oxide synthase inhibitor NOARG, suggesting a role for nitric oxide in ethanol hypotension. The inability of ethanol to lower blood pressure in NOARG-treated rats cannot be attributed to the presence of elevated blood pressure in these rats because ethanol produced hypotension when blood pressure was raised to comparable levels with phenylephrine infusion. Selective inhibition of iNOS by aminoguanidine (45 mg/kg ip), which had no effect on baseline blood pressure, abolished both the hypotensive action of subsequently administered ethanol and the associated increases in aortic iNOS content. These findings implicate vascular iNOS, at least partly, in the acute hypotensive action of ethanol in female rats.

Animals↗
PubMed2005

Vortex lattices in planar Bose-Einstein condensates with dipolar interactions.

In this Letter, we investigate the effects of dipole-dipole interactions on the vortex lattices in fast rotating Bose-Einstein condensates. For single planar condensate, we show that the triangular lattice structure will be unfavorable when the s-wave interaction is attractive and exceeds a critical value. It will first change to a square lattice, and then become more and more flat with the increase of s-wave attraction, until the collapse of the condensate. For an array of coupled planar condensates, we discuss how the dipole-dipole interactions between neighboring condensates compete with quantum tunneling processes, which affects the relative displacement of two neighboring vortex lattices and leads to the loss of phase coherence between different condensates.

Journal Article↗