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Biomedical subjects

Z Y Shen

Publications and source records attributed to Z Y Shen.

At least 19 recordsLinked to original sources
PubMed2006

QSPRs for the prediction of photodegradation half-life of PCBs in n-hexane.

By partial least squares (PLS) regression analysis, a quantitative structure-property relationship (QSPR) model was developed for photodegradation half-life (t1/2) of polychlorinated biphenyls (PCBs) in n-hexane solution under UV irradiation. Quantum chemical descriptors computed by PM3 Hamiltonian were used as predictor variables. The cross-validated value for the optimal QSPR model was 0.589, indicating good predictive capability for log t1/2 values of PCBs in n-hexane. The QSPR results show that standard heat of formation (DeltaHf), total energy (TE), and molecular weight (Mw) have dominant effect on t1/2 values of PCBs in n-hexane. Increasing DeltaHf and TE values or decreasing Mw values of the PCBs leads to decrease of log t1/2 values. In addition, increasing the largest negative atomic charge on a carbon atom and dipole moment of the PCBs leads to decrease of log t1/2 values.

Environmental Pollutants↗
PubMed2006

Relationship between HPV16/18 E6 and 53, 21WAF1, MDM2, Ki67 and cyclin D1 expression in esophageal squamous cell carcinoma: comparative study by using tissue microarray technology.

AIM: To investigate the role of human papillomavirus (HPV) HPV16/18 E6 oncogene in the carcinogenesis of esophageal cell carcinoma (ESCC). MATERIALS AND METHODS: Tissue microarray (TMA) block was constructed from 60 cases of paraffin-embedded ESCC tissues and pair-matched controls (adjacent normal epithelium). Immunohistochemistry (IHC) methods were applied to detect the expression of HPV16/18 E6, p53, p21(WAF1), MDM2, Ki67 and cyclin D1 proteins on TMA slides. In situ hybridization (ISH) targeting HPV gene was also used. RESULTS: In ESCC samples, 18.3% (11/60) were revealed HPV16/18 E6 positive by IHC, while 40.0% (24/60) HPV positive by ISH; HPV16/18 E6 expression was significantly higher than that of control samples. In ESCC samples, the expressions of p53, p21(WAF1), Cyclin D1, MDM2 and Ki67 were recorded in 60.0% (36/60), 40.0% (24/60), 51.7% (31/60), 65.0% (39/60) and 88.3% (53/60) cases respectively, In ESCC samples, p53, MDM2 and Ki67 expression correlated with the HPV16/18 E6 expression (p less, similar 0.01), p21(WAF1) expression - with these of MDM2 and cyclin D1 (p less, similar 0.01) whilst expression of Ki67 - with ESCC grade (p less, similar 0.01). CONCLUSION: HPV might be one of etiological factor of esophageal carcinoma in Shantou, China. p53, MDM2 proteins may play important roles in the pathogenesis of HPV-associated ESCC.

Adult↗
PubMed2006

[Synergistic effects of human papillomavirus and phorbol ester in cell transformation.].

BACKGROUND: To investigate the molecular mechanism of the synergistic effects of human papillomavirus (HPV) and phorbal esters (TPA) in cell transformation. METHODS: The expression of oncogenes and anti-oncogenes in 293 cell line treated with HPV and TPA was studied by Southern Blot and RNA dot blot. RESULTS: It was found that the synergistic effect induced the amplification of c-myc (4-8 times), increased expressing level of c-erbB-2 (32-64 times) and decreased expressing level of p16(1/4-1/8). CONCLUSION: The above results show that the synergistic effect has an important role in development of carcinoma.

Cell Line↗
PubMed2005

Role of fascin in the proliferation and invasiveness of esophageal carcinoma cells.

Fascin, an actin-bundling protein, induces membrane protrusions and increases cell motility in various transformed cells. The overexpression of fascin in esophageal squamous cell carcinoma (ESCC) has been described only recently, but the roles and mechanism still remained unclear. Here, by using RNA interference (RNAi), we have stably silenced the expression of the fascin in EC109 cells, an ESCC cell line. Down-regulation of fascin resulted in a suppression of cell proliferation and as well as a decrease in cell invasiveness. Furthermore, we revealed that fascin might have functions in regulating tumor growth in vivo. The effect of fascin on cell invasiveness correlated with the activation of matrix metalloproteases such as MMP-2 and MMP-9. We examined that fascin down-expression also led to a decrease of c-erbB-2 and beta-catenin at the protein level. These results suggested that fascin might play crucial roles in regulating neoplasm progression of ESCC.

Animals↗
PubMed2001

E-cadherin expression is commonly downregulated by CpG island hypermethylation in esophageal carcinoma cells.

E-cadherin, a cell adhesion molecule, is regarded as an invasion-suppressor molecule and a prognostic marker in many types of human cancers. Downregulation of E-cadherin is common in esophageal carcinoma and is associated with an increase in invasive and metastatic potential. To study the mechanisms responsible for inactivation of this gene in esophageal squamous cell carcinoma (ESCC), we investigated the methylation status around the 5' promoter region of E-cadherin gene of six ESCC cell lines by methylation-specific polymerase chain reaction, and compared it with E-cadherin protein and mRNA expression. We also studied the methylation status of 20 ESCC clinical specimens. Methylation was noted in four of the six cell lines (one fully methylated and three partially methylated). The completely methylated cell line lacked E-cadherin protein expression and mRNA transcription. E-cadherin expression and transcription were reduced in a partially methylated cell line but preserved in the other partially methylated cell lines. Treatment of E-cadherin-negative carcinoma cells with the demethylating agent, 5-aza-2'-deoxycytidine, induced re-expression of the gene. A high frequency of methylation (16/20, 80%) was also noted in the 20 ESCC clinical samples. Our results indicate that 5' CpG island methylation is common in esophageal carcinoma and may play an important role in downregulation of E-cadherin.

Azacitidine↗
PubMed2001

Accumulation of poly-beta-hydroxybutyrate in cyanobacterium Synechocystis sp. PCC6803.

Accumulation of poly-beta-hydroxybutyrate (PHB) by photoautotrophic microorganisms makes it possible to reduce the production cost of PHB. The Synechocystis sp. PCC6803 cells grown in BG11 medium under balanced, nitrogen-starved or phosphorus-starved conditions were observed by transmission electron microscope. Many electron-transparent granules in the nitrogen-starved cells had a diameter up to 0.8 micron. In contrast, the number of granules in the normally cultured cells decreased obviously and only zero to three much smaller granules were in each cell. These granules were similar to those in bacteria capable of synthesizing PHB. They were proved to be PHB by gas chromatography after subjecting the cells to methanolysis. Effects of glucose as carbon source and light intensity on PHB accumulation in Synechocystis sp. PCC6803 under nitrogen-starved cultivation were further studied. Glucose and illumination promoted cell growth but did not favor PHB synthesis. After 7 days of growth under nitrogen-starved photoautotrophic conditions, the intracellular level of PHB was up to 4.1% of cellular dry weight and the PHB concentration in the culture broth was 27 mg/l.

Biotechnology↗
PubMed2001

Human papillomavirus 16 E6 is associated with the nuclear matrix of esophageal carcinoma cells.

AIM: To explore the etiologic role of HPV infection in esophageal carcinoma, and the association of HPV-16 E6 with the nuclear matrix of carcinoma cells. METHODS: Two esophageal carcinoma cell lines,EC/CUHK1 and EC/CUHK2, were tested for HPV-16 E6 subgenetic fragment by polymerase chain reaction amplification of virus DNA associated nuclear matrix. RT-PCR and immunocytochemistry were also used to visualize the expression of E6 subgene in the cells. RESULTS: The HPV-16 E6 subgenetic fragment was found to be present in nuclear matrix-associated DNA, E6 oncoprotein localized in the nucleus where it is tightly associated with nuclear matrix after sequential extraction in EC/CUHK2 cells. It was not detected, however, in EC/CUHK1 cells. CONCLUSION: The interaction between HPV-16 E6 and nuclear matrix may contribute to the virus induced carcinogenesis in esophageal carcinoma.

Antigens, Nuclear↗
PubMed2001

The genetic events of HPV-immortalized esophageal epithelium cells.

We studied cytogenesis, telomere and telomerase, and c-myc, ras, bcl-2, and p53 genes of cells in the progressive process of immortal epithelial cells from embryonic esophagus induced by human papillomavirus (HPV). The SHEE cell line, established by us, consist of immortalized epithelial cells from the embryonic esophagus induced by genes E6E7 of HPV type 18. It was in initial malignant transformation when cultivated over 60 passages without co-carcinogens. Cells of the 10th, 31st, and 60th passages were represented in the progressive process within the immortal period. In these three stages of the cell line, the modal number of chromosome and karyotypes were analyzed. The telomere length was assayed by Southern blot methods, and the telomerase activity was analyzed by hTR and hTERT assay. C-myc, p53, bcl-2, ras genes were assayed by the multi-PCR method. The morphology of the 10th passage cells exhibited good differentiation, the 60th passage cells were relatively poorly differentiated, and the 31st passage cells differentiated in two distinct ways. The growth characteristics of the 31st and 60th passage cells were weakened at contact-inhibition and anchorage-dependent growth. Karyotypes of three cell passages belonged to hyperdiploid and hypotriploid with abnormal chromosomes +1, +3, +7, +9, +17, +18; del(1)(p32); der(4), t(4;?)(q31;?); der(5),t(5;?)(q31;?); der(13),t(13;13)(p11;q11) and others. Bimodal distribution of chromosomes with more aberrant chromosomes appeared in the 31st and 60th passage cells. Telomere length sharply shortened from normal fetal esophagus to the 10th and 31st passage step by step, but was stable from the 31st to the 60th passage and the telomerase activities measured were expressed at late two passages. p53 mutant was positive in three passages, c-myc was positive in the 31st and the 60th passage K-ras only in the last. The results reveal that changes of chromosomes, telomere length, telomerase activity and certain gene expressions are important events of HPV-immortalized esophageal epithelium cells. All of these changes occurred in dynamic progressive process. This cell line may be useful for the elucidation of the genetic mechanism of cellular immortalization.

Cell Line, Transformed↗
PubMed2001

A comparative study of telomerase activity and malignant phenotype in multistage carcinogenesis of esophageal epithelial cells induced by human papillomavirus.

To examine certain characteristics of multistep carcinogenesis, we studied telomerase activity and malignant phenotypes in the immortal, premalignant and malignant stages of esophageal epithelial cells induced by HPV. An immortalized human fetal esophageal epithelial cell line (SHEE) was induced by E6E7 genes of human papillomavirus (HPV) type 18. Cells in the 10th passage, (SHEE10), 31st passage (SHEE31), 61st passage (SHEE61) and SHEE61A which were selected and expanded from anchorage-independent growth colonies of SHEE61, were examined as follows: cell morphology by electron-microscopy; the cell cycle by flow cytometry, telomerase activity by TRAP assay, tumorigenic detection including anchorage-independent growth by soft agar culture and tumor formation by inoculating cells into SCID and nude mice, and detection of HPV18 E6E7 oncoprotein by Western blot. The morphology of the SHEE10 cells exhibited good differentiation, the SHEE60 and SHEE61A cells were relatively poorly differentiated, and the SHEE31 cells were differentiated in two distinct ways. The telomerase was activated in SHEE31, SHEE61 and SHEE61A, but not in SHEE10 cells. SHEE61 and SHEE61A cells were weakened in contact-inhibition and increased in anchorage-independent growth. Inoculated into SCID and nude mice, the cells of the earlier two passages could not develop tumors; the SHEE61 developed one tumor in four SCID mice, but not in nude mice, and the SHEE61A cells developed tumors in both strains of immunodeficient mice. HPV18 E6E7 DNA detection by Western blotting was positive in all cell passages. In the process of carcinogenesis by HPV, the cells of SHEE31 are in an immortalized state with telomerase activity. The fact that SHEE61 cells remained immortalized and also demonstrated anchorage-independent growth, reveals premalignant character; the cells of SHEE61A exhibited malignant transformation with tumor formation in mice. The results revealed that the telomerase activity, anchorage-independent growth and tumor formation in nude mice are the indicators for immortalization, premalignancy and malignancy, respectively.

Animals↗
PubMed2001

Estimation of the radionuclide distribution in sediment in coast area.

The study of the radionuclide distribution in sediment is a very important aspect in environmental impact of the low level radioactive liquid waste (LLW) from coastal nuclear facilities or nuclear power plant. Even now we do not know much about it. In this paper, a simple and useful method is put forward and it is used to estimate the nuclide distribution in sediment. The result showed that the LLW from nuclear facility or nuclear power plant will do a little harm to the sediment nearby. But the harm is not very serious. Much works have to be done before full understanding of the situation.

Environmental Monitoring↗
PubMed2001

Effects of microinjection of melatonin and its receptor antagonists into anterior hypothalamic area on blood pressure and heart rate in rats.

AIM: To examine the effects of microinjection of melatonin and its receptor antagonists into the anterior hypothalamic area (AHA) on blood pressure (BP) and heart rate (HR) in normotensive and stress-induced hypertensive rats. METHODS: Melatonin and its receptor antagonists were microinjected into the AHA, then BP, mean arterial pressure (MAP), and HR were synchronously recorded. RESULTS: Microinjection of melatonin produced a fall in MAP. Prazosin, an antagonist of melatonin ML2 receptor, could not antagonize the depressive response induced by melatonin. While luzindole, a competitive antagonist of melatonin ML1 receptor, was able to almost completely prevented the depressive response induced by injection of melatonin. CONCLUSION: Melatonin acts as a hypotensive factor and the effects are mainly due to activation of ML1 receptors in rat brain, and the AHA may be one of the important central areas where melatonin can exert modulatory effects on BP and HR.

Animals↗
PubMed2000

The alteration of mitochondria is an early event of arsenic trioxide induced apoptosis in esophageal carcinoma cells.

It is accepted that inorganic arsenic trioxide is an inducer of apoptosis for many types of cancer. Our previous studies have demonstrated that arsenic trioxide induces apoptosis of esophageal carcinoma cells. Administration of arsenic trioxide results in the inhibition of growth and survival of tumor cells. Esophageal carcinoma cells treated with arsenic trioxide for 3 days demonstrated a typical morphological appearance of apoptosis. To further examine molecular mechanism of arsenic trioxide induced apoptosis of esophageal carcinoma cells, we have investigated the early changes of the apoptotic cell induced by arsenic trioxide. Our results indicated that arsenic trioxide induced apoptosis of esophageal carcinoma cells occurs as early as 2 h after treatment. Annexin-v staining has further proved that the phosphatidylserine is exposed at 2 h. The early morphological change of arsenic trioxide treated cells was in the mitochondria. Arsenic trioxide treated cells displayed aggregated mitochondria. It induces accumulation of high electron-density amorphous substances, swollen and disruption of mitochondria in oesophageal carcinoma cells after 2 h treatment. The alteration of mitochondria induced by arsenic trioxide seems to occur before the condensation of chromatin. Thus, our data demonstrated that the primary target of arsenic trioxide induced apoptosis of esophageal carcinoma cells may be the mitochondria. It is possible that arsenic trioxide is a mitochondriotoxic agent.

Antineoplastic Agents↗
PubMed2000

[Study on protein separation using immobilized metal ion affinity chromatography].

Immobilized metal ion affinity chromatography (IMAC) has shown promise of isolating desired proteins from a mixture based on their difference of affinity for chelated metal ions. With its technological superiority, such as large adsorption capacity, mild separation condition, simple ligands and wide applications, IMAC has become powerful tool for biotechnological products separation, such as proteins, amino acids and gene products. In spite of many sophisticated applications for IMAC, the theoretical analysis of Immobilized metal chromatography has remained insufficient. In this paper, the eluted efficiencies of bovine serum albumin (BSA) in a single-component system under different elution conditions are studied. The effects of several elution factors, such as pH value, ammonium concentration and anion species on protein separation are studied. Comparing the elution data of BSA in IDA-Cu and IDA-Zn columns, the different ability of affinity between metal ions and proteins is found. In addition, the elution behaviors of different proteins are investigated. This work facilitates the further research in separation of real systems.

Chromatography, Affinity↗
PubMed2000

[Repair of severe radiation-induced ulcer].

OBJECTIVE: To explore a method to repair severe radiation-induced ulcer and evaluate its clinical effects. METHODS: From August 1988 to December 1998, 12 cases of severe radiation-induced ulcer were treated by muscular or musculocutaneous flap transfer, which included 1 case of pectoralis major muscular flap, 3 cases of three-lobed transverse rectus abdominis musculocutaneous flap, 2 cases of latissimus dorsi musculocutaneous flap, 1 case of tensor fascia lata musculocutaneous flap, 1 case of longitudinal rectus abdominis musculocutaneous and tensor fascia lata musculocutaneous flap, 1 case of gastrocnemius muscular flap, 1 case of gluteus major musculocutaneous flap, huge filleted musculocutaneous flap from lower limbs in 1 case and from upper limbs in 1 cases. RESULTS: All the flaps survived. Primary healing occurred in 9 cases and secondary healing in 3 cases. The extensive multiple ulcers in 2 cases were repaired with filleted limb musculocutaneous flap, and patients were saved. And in other 3 cases, the chest wall defect as the result of radionecrosis were repaired with simultaneous breast reconstruction. CONCLUSION: Muscular or musculocutaneous flaps have abundant blood supply, they are ideal tissue to fill the cavity and repair the defect, especially in repairing severe radiation-induced ulcers.

Adult↗
PubMed2000

[Application of skin and soft tissue expansion in treatment of burn injury].

OBJECTIVE: To evaluate the application of skin and soft tissue expansion in the treatment of deformity due to extensive severe burn injury and repair of severe deep electrical burned scalp and skull with fresh wound. METHODS: From 1988, 83 cases of application of skin and soft tissue expansion were reported. In those patients with deformity due to severe burn of large area and with whole nasal defect, soft tissue expander was used under the forehead skin graft and venter frontalis, followed by reconstruction of nose with the expanded vascularized skin flap and carved cartilago costalis as nasal frame. In patients of severe deep electrical burned scalp and skull with fresh wound, skin and soft tissue expansion were used to repair the wound simultaneously with scalp burn alopecia, anesthetics and antibiotics injected into the extracapsular space of the expander in case of pain and infection. RESULTS: All of the cases were successfully treated with little pain and minimized infection. CONCLUSION: Skin and soft tissue expansion in a safe and reliable measure in the treatment of deformity due to extensive severe burn injury and repair of severe deep electrical burned scalp and skull with fresh wound.

Adolescent↗
PubMed1999

Arsenic trioxide induces apoptosis of oesophageal carcinoma in vitro.

The arsenic compounds in traditional Chinese medicine have been recorded to have therapeutic effects on the treatment of psoriasis, syphilis, rheumatosis and a number of malignant tumours. Recent studies showed that arsenic trioxide can induce clinical remission in patients with acute promyelocytic leukemia, including those who have relapsed after retinoic acid treatment. however, the mechanism of how arsenic trioxide targets tumour cells is not clearly understood. We have examined the effects of arsenic trioxide on oesophageal carcinoma cell line EC8712. Our results demonstrated that the growth and survival of tumour cells were markedly inhibited by arsenic trioxide. The half dose effect (ED50) was at the concentration of 1 microM. Electron microscopic study demonstrated that EC8712 tumour cells treated with arsenic trioxide display a typical morphological appearance of apoptosis, including chromatin condensation and fragmentation of the nuclei. In contrast, no apoptotic features were observed in tumour cells without arsenic trioxide treatment. TUNEL assay also showed the biological features of apoptosis in cells treated with arsenic trioxide. Flow cytometry analyses showed that apoptotic peak was identified in arsenic trioxide treated cells but not in the control. Apoptotic cells in arsenic trioxide treated group account for 35% of total cell populations after three days treatment at a dose of 3 microM. In short, our results suggested that the anticancer effect of arsenic trioxide is due, at least in part, to the induction of apoptosis in cancer cells.

Antineoplastic Agents↗