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Biomedical subjects

Wei Shi

Publications and source records attributed to Wei Shi.

At least 73 records · Page 4Linked to original sources
PubMed2005

Comparisons between oral pulse alfacalcidol therapy and daily therapy in maintenance hemodialysis patients with secondary hyperparathyroidism: a randomized, controlled, and multicenter study.

OBJECTIVE: To investigate the efficacy and safety of 1alpha-(OH)-D3 high-dose pulse therapy or daily low-dose therapy in secondary hyperthyroidism in maintenance hemodialysis patients in China. METHODS: Maintenance hemodialysis patients of both gender with intact parathyroid hormone (iPTH) level above 200 pg/mL were randomly divided into a pulse group and a daily group. They were treated for 20 weeks, with 2 microg oral Alfacalcidol twice weekly or thrice weekly in the pulse group, and 0.5 microg oral Alfacalcidol per day in the daily group. The therapeutic end point was parathyroid hormone level < 200 pg/ mL. The iPTH levels during the study were monitored, and parameters representative of calcium and phosphate metabolism and side effects were also observed. RESULTS: One hundred and fifty-eight patients were initially enrolled, 91 in the pulse therapy group and 67 in the daily therapy group. There was no significant difference in age, hemodialysis duration, proportion of diabetic nephropathy and systemic diseases, proportion of patients who had received active vitamin D therapy previously, mean initial iPTH level (pulse group 570.47 +/- 295.86 pg/mL; daily group 498.33 +/- 207.84 pg/mL), serum calcium, serum phosphate, alkaline phosphatase (AKP), and albumin between two groups. In the pulse therapy group there were more patients with iPTH levels of 500 to approximately 1,000 pg/mL and > 1,000 pg/mL, so stratified analysis according to iPTH level was used. In therapeutic end point, iPTH levels in both groups were significantly lower compared with those before therapy (pulse group 261.29 +/- 234.97 pg/mL, P < .01; daily group 262.17 +/- 274.82 pg/mL, P < .01). After 4 weeks, the ratio of reaching end point in the pulse group was 35.2%, which was significantly higher than that (19.4%) in the daily group (P < .05). More obvious change was seen in the 200 to approximately 500 pg/mL subgroup by stratified analysis (P < .05), whereas there was no significant difference between the 500 to approximately 1,000 pg/mL and > 1,000 pg/mL subgroup (P > .05). At therapeutic end point, the total ratio of reaching end point did not differ between the two groups, and there were no obvious differences between each subgroup. In the iPTH 200 to approximately 500 pg/mL subgroup, mean iPTH%/week in the pulse group was significantly higher than that in the daily group, and no obvious difference was seen in other subgroups. AKP levels decreased significantly in both groups at therapeutic end point (pulse group 98.42 +/- 54.52 vs. 74.21 +/- 30.68 IU/L, P < .01; daily group 103.3 +/- 68.04 vs. 75.40 +/- 34.12 IU/L, P < .01). On the 4th week, AKP level in pulse group (82.39 +/- 35.23 IU/L) was significantly lower than the initial level (98.42 +/- 54.52 IU/L, P < .05), whereas in the daily group there was no difference between each week. The mean serum calcium, phosphate, and [Ca2+] x [P3+] levels in both groups did not change greatly. Nine patients in the pulse group (9.9%) and 8 patients in the daily group (11.9%) suffered hypercalcemia at least once. Persistent hypercalcemia occurred in 8 patients in the pulse group (8.8%) and 9 patients in the daily group (13.4%), but the difference in proportion did not show statistical significance. The serum phosphate in the daily group was higher after the therapy (1.74 +/- 0.36 vs. 1.89 +/- 0.36 mmol/L, P < .05), whereas that in the pulse group remained unchanged. At therapeutic end point, [Ca2+] x [P3+] level in the daily group was higher than that before the therapy (48.04 +/- 11.71 vs. 55.46 +/- 12.66, P < .05), whereas in the pulse group there was no significant difference. Side effects for both groups were minimal and well tolerated. CONCLUSIONS: Alfacalcidol [1alpha-(OH)-D3] has good and safe effects on secondary hyperparathyroidism in maintenance hemodialysis patients. The efficacy and early effects of pulse therapy are superior to those of daily therapy in moderate hyperparathyroidism patients.

Administration, Oral↗
PubMed2005

[Survey on the contamination of microcystin-LR in water supply of Shanghai city].

OBJECTIVE: To study the pollution level of microcystin-LR in water supply of Shanghai city and the removal efficacy for microcystin-LR through routine water treatment technique. METHODS: High performance liquid chromatogram (HPLC) was applied to determine the concentration of microcystin-LR in source water, water samples after various water treatment procedures and tap water. RESULTS: The concentration of microcystin-LR varied with sampling seasons and sites and reached peak during summer and fall. The maximum of microcystin-LR was 2.38 microg/L in source water. Coagulation plus chlorine disinfection were found to be effective for the removal of microcystin-LR, while the remove rate through filtration was not significant. And it could also be detected in tap water as high as 1.27 microg/L. CONCLUSION: The source waters of Shanghai city were polluted by cyanobacteria toxins represented by microcystin-LR. The source water in suburb was more polluted. Routine water treatment techniques can not remove the toxins effectively.

China↗
PubMed2005

[Antagonistic effects of selenium on the expression of c-fos in central nerval system of rat included by mercury contaminated rice].

The objective of this paper is to study the antagonisms between selenium and mercury and the effect of different species mercury on the brain injury. The expression of c-fos mRNA and c-FOS protein in rat brain induced by Hg-contaminated rice was observed by using reverse transcriptions polymerase chain reaction (RT-PCR) and immunocytochemical methods. The results show the Hg-contaminated rice induced significantly the expression of c-fos mRNA and c-FOS protein; selenium could antagonize mercury accumulative level in brain. Antagonistic effects of selenium on the expression of c-fos included by mercury and the molecule mechanism of the antagonisms between selenium and mercury was probed, too.

Animals↗
PubMed2005

[Effects of CD147 on the production of matrix metalloproteinase-9 by fibroblasts and the invasion of melanoma cells].

OBJECTIVE: To investigate a possible role of CD147 in the production of matrix metalloproteinase-9 (MMP-9) by fibroblasts and the invasion of melanoma cells. METHODS: We cocultured CD147-expression melanoma cells with fibroblasts and examined the MMP-9 expression of fibroblasts by zymography and the invasion of melanoma cells by transwell invasion assay. RESULTS: MMP-9 expression was enhanced in conditioned media, while cocultured with melanoma cells in a dose-dependent manner, and CD147 antibody inhibited the production of MMP-9 in the fibroblasts. When fibroblasts were cultured at the bottom of the lower compartment of transwell invasion model, the number of melanoma cells that invaded significantly increased. Addition of anti-CD147 antibody to the upper compartment transwell invasion model resulted in the significant inhibition of the melanoma cell invasion in reconstituted basement membrane. CONCLUSION: CD147 expressed in melanoma cells plays an important role in the melanoma cell invasion by stimulating the production of MMP-9 by fibroblasts.

Basigin↗
PubMed2005

[Progression of study on the health effects of indoor biological contaminants].

The use of HVAC (the heating, ventilation and air conditioning) system which leads to the inadequate circulation of indoor air, together with the popularization of family pets, creates an appropriate environment for survival and reproduction of air-borne microbes. Microbes with their toxin and allergen in air often adhere to saliva and particular matters, landing to the ground or floating in air for long time. Potential adverse health consequences may be led to subjects exposed to the biological contaminants. In particular, the disorders from the respiratory and allergic response were often reported. The progresses of studies on the biological contaminants during recent ten years were reviewed in the paper.

Air Conditioning↗
PubMed2005

[Study on the effectiveness and cost-benefit of influenza vaccine on elderly population in Beijing city].

OBJECTIVE: To estimate the effectiveness of inactivated influenza vaccine in elderly population. METHODS: An quasi-experimental study was used. 590 elderly people who volunteered to receive the influenza vaccine were served as vaccine group, while 602 persons who did not want to receive the inoculation but could match the vaccine group were served as controls. One baseline and three follow-up surveys were carried out. RESULTS: The protective rates of influenza like ill (ILI) as 52.38%, 36.84% and 37.89% with the decreasing rates of visits to ILI clinic as 45.16%, 50.54% and 50.54% were found after 1 month, 3 month and 6 month of inoculation of influenza vaccine; The protective rates of common cold, other respiratory tract or chronic disease were 49.54%, 64.54%, and 38.82%, respectively. The benefit-cost ratio was 4.98:1 in elderly population. CONCLUSION: Influenza vaccination could decrease ILI incidence and recurrence rates of related chronic diseases on elderly population to provide better economic benefits for the elderly.

Aged↗
PubMed2005

Effects of mercury contaminated rice from typical chemical plant area in China on nitric oxide changes and c-fos expression of rats brain.

China is one of countries with the highest mercury production in the world. The Guizhou Province in Southwestern China is currently one of the world's most important mercury production areas. In order to study the neurotoxicity of rice from Qingzhen Chemical Plant area and probe into the signal transduction molecular mechanism of injury in rat brain stimulation by mercury contaminated rice. The rats were exposed to mercury contaminated rice for 20 d. Both of the measurements of NO and NOS were processed according to the protocol of the kit. The effect of Hg contaminated rice on the expression of c-fos mRNA in rat brain and the expression of c-FOS protein in cortex, hippocampus were observed using reverse transcription polymerase chain reaction (RT-PCR) and immunocytochemical methods. The results showed the neural transmitter NO and NOS in brain were significantly change between exposure groups and control group; the mercury polluted rice induced significantly the expression of c-fos mRNA; the c-FOS positive cells in hippocampus and cortex of exposure groups were significant different from control group (p < 0.01). It could be concluded that nitric oxide was involved in mercury contaminated rice induced immediate early gene c-fos expressions in the rat brain. Through food chain, local ecosystem and health of local people iave been deteriorated seriously by mercury. This serious situation will last a long period. In order to alleviate mercury pollution, more work needs to do.

Animals↗
PubMed2005

[Eutrophication and pollution level of microcystin in Dianshan Lake].

A survey was conducted in Dianshan Lake to study the eutrophication indexes including total phosphorus (TP), total nitrogen (TN), pH, temperature, diaphaneity and chlorophyll-a level and dominant algae in seasons. The impacts of temperature, light, nitrogen and phosphorus on growth of and microcystin LR production by Microcystis aeraginosa strain under laboratory conditions were studied. Relationship between algal cell density and concentration of microcystin LR were studied. Results suggest that water in Dianshan Lake was eutrophicated. The suitable seasons for algae growth are the end of spring and summer. The annual average of TP and TN were 1.93 mg/L and 0.18 mg/L respectively. And 93.5 and 92.2 percent of TP and TN were higher than the criteria for the third class water body. Significant impact from agriculture was indicated since the peak of algae laged one month after the maxium use of fertilizer. The dominant algae in Dianshan Lake were cyanobacteria, bacillariophyta, cryptophyta and euglenophyta. Microcystis, anabaena and synedra, which excrete toxins and indicate water pollution, and are dominant algae species in summer. M. aeraginosa strain had a biggest growth rate at temperature of 25 degrees C and light intensity of 3 0001x, while microcystin LR production contents reached maximum at 20 degrees C and 5000lx respectively. The optimum TP and TN concentrations for growth of and toxin production by M. aeraginosa were found to be 650 micromol/L and 6.5 micromol/L respectively. TP is suspected to be the limiting factor for the growth of algae both in field and laboratory conditions. Positive correlations between total microcystin LR concentrations and algae cell density or M. aeraginosa cell densities are found. The algae cell density can be used to predict the level of algal toxins in water.

China↗
PubMed2005

[Study on DNA damage induced by microcystin-LR].

OBJECTIVE: To investigate whether microcystin-LR (MC-LR) at doses which were not cytotoxic can induce DNA damage and compare its effect on HL-7702 and KB cell lines. METHODS: Cytotoxin and DNA damage were detected by MTT and comet assay, respectively. RESULTS: As doses ranged from 10 to 100 micro/L, MC-LR showed no significant impact on viability of these two cell lines. However, DNA damage induced by MC-LR occurred at the dose of 30 microg/L in HL-7702 cell and significantly increased with dose. MC-LR did not induce DNA damage in KB cell. CONCLUSION: MC-LR has potential genotoxicity, DNA damage induced by MC-LR is more significant in hepatocyte with bile acid transportation system than other cell lines.

Cell Line↗
PubMed2005

[Construction of eukaryotic expression vector of mouse alpha-fetoprotein cDNA and its expression in dendritic cells and in vitro antitumor effect on hepatoma].

BACKGROUND & OBJECTIVE: Studying the mechanism of why the abnormal protein coded by mutant gene of hepatoma carcinoma cell possesses potential antigenicity, but can not form effective immunogen, searching for specific antigen of hepatoma, and developing DNA vaccine for hepatoma treatment will have active impact on the immunotherapy of hepatoma. This study was to construct fluorescent eukaryotic expression vector of mouse alpha fetoprotein (AFP) cDNA fragment with or without the secretory signal peptide (termed AFP1 cDNA and AFP2 cDNA), and observe its expression in mouse dendritic cells (DCs) and in vitro antitumor effect on hepatoma. METHODS: AFP1 cDNA and AFP2 cDNA were amplified from mouse hepatoma cell line H22 by reverse transcription-polymerase chain reaction (RT-PCR), and cloned into eukaryotic expression vector PEGF-N3 to form the recombinant PEGF-N3/AFP1 and PEGF-N3/AFP2. The mouse bone marrow cells were induced with recombinant granulocyte-macrophage colony-stimulating factor (rmGM-CSF) and recombinant interleukin-4 (rmIL-4) to form mature DCs. The recombinant PEGF-N3/AFP1 and PEGF-N3/AFP2 were transfected into DCs. The DCs vaccine were co-cultured with isogenous mouse spleen lymphocytes. The expression of gamma-interferon (IFN-gamma) in the spleen lymphocytes stimulated by AFP1/DCs or AFP2/DCs was measured by ELISA assay; the specific killing activity of cytotoxic T lymphocytes (CTLs) was evaluated by 51Cr release assay. RESULTS: Sequencing analysis verified that AFP1 cDNA and AFP2 cDNA were correctly amplified from H22 cells. The recombinant PEGF-N3/AFP1 and PEGF-N3/AFP2 were stably expressed in mouse DCs. AFP2/DCs obviously stimulated proliferation of T lymphocytes; the stimulation index (SI) was significantly higher in AFP2/DCs group than in AFP1/DCs group, empty vector group, and blank control group (5.12 +/- 1.46 vs. 1.41 +/- 0.65, 1.42 +/- 0.7, and 1.41 +/- 0.55, P < 0.01); the specific killing activity of CTLs was stronger in AFP2/DCs group than in empty vector group [(88.15 +/- 16.4)% vs. (12.72 +/- 5.45)%]. CONCLUSION: The recombinant expression vectors PEGF-N3/AFP1 and PEGF-N3/AFP2 with or without signal peptide were constructed successfully. AFP2/DCs can specifically activate T lymphocytes in vitro and effectively induce antitumor immune response.

Animals↗
PubMed2004

Abnormal mouse lung alveolarization caused by Smad3 deficiency is a developmental antecedent of centrilobular emphysema.

Transforming growth factor-beta (TGF-beta) signaling plays an important regulatory role during lung development and remodeling. Smad3 is a major downstream signal transducer in the TGF-beta pathway from the cell membrane to the nucleus. In Smad3 null mutant mice, we have observed retarded lung alveolarization from postnatal day 7 to day 28, and subsequently centrilobular emphysema starting from day 28, as determined by morphometric analysis. In addition to the morphological changes, peripheral lung cell proliferation in Smad3 knockout mice was reduced compared with the wild-type control between postnatal days 7 and 28. Expression of tropoelastin at the mRNA level was also dramatically decreased in Smad3 knockout lungs from postnatal day 28 through adulthood. Furthermore, increased matrix metalloproteinase-9 protein expression and activity were detected in the Smad3 knockout mouse lung tissue and the bronchoalveolar lavage fluid at postnatal day 28 when the centrilobular emphysema pathology was just beginning to appear. Therefore, these results indicate that Smad3 not only has a positive regulatory impact on neonatal lung alveolarization but also potentially plays a protective role against the occurrence of centrilobular emphysema later on in life.

Animals↗
PubMed2004

Selective and sensitive fluorescent sensors for metal ions based on manipulation of side-chain compositions of poly(p-phenyleneethynylene)s.

The syntheses and metal-responsive properties of poly(p-phenyleenethynylene)s with grafted new pseudo-crown-ether groups are reported. These polymers exhibit high sensitivities to alkali ions because of their collective optical properties, which are very sensitive to ion-induced conformational changes. The quenching of polymer fluorescence caused by the conformational changes is proportional to the ion concentration. The selectivity of the sensing materials toward Li(+) ions is significantly enhanced by controlling the size of the binding site via manipulation of the polymer side-chain compositions. The polymers are very stable for their six-month solid-state storage at room temperature.

Letter↗
PubMed2004

Choroideremia gene product affects trophoblast development and vascularization in mouse extra-embryonic tissues.

Choroideremia (CHM) is a hereditary eye disease caused by mutations in the X-linked CHM gene. Disruption of the Chm gene in mice resulted in prenatal death of Chm-/Y males and Chm-/Chm+ females that had inherited the mutation from their mothers. Male chimeras and Chm+/Chm- females with paternal transmission of the mutation were viable and had photoreceptor degeneration reminiscent of human choroideremia. Here, we show that Chm-/Y males and Chm-/Chm+ females were retarded at e7.5 and died before e11.5 due to multiple defects of the extra-embryonic tissues. Mutant embryos exhibited deficiency of diploid trophoblasts associated with overabundance of giant cells. In yolk sac and placenta, severe defects in vasculogenesis were obvious. Chm-/Y males exhibited more pronounced phenotypes than Chm-/Chm+ females. The lethal genotypes could be rescued by tetraploid aggregation. Chm-/Chm+ females, but not Chm-/Y males, could also be rescued when their Chm+/Chm- mothers were mated with Mus spretus males. Backcross analysis suggested that the viability of interspecies hybrid Chm-/Chm+ females may be due to expression from the Chm allele on the M. spretus X-chromosome rather than a modifier effect. Our results demonstrate that Chm is essential for diploid trophoblast development and plays a role in the vascularization in placenta and yolk sac.

Alkyl and Aryl Transferases↗
PubMed2004

[The maintenance of cord blood CD34+ progenitor cells with plant lectin FRIL in vitro and the expression of related cell cycle modulator HTm4 and HTm4S].

Ex vivo maintainance of human stem cells is crucial for many clinical applications. Current culture conditions provide some level support but cytokines induce most quiescent stem cells to proliferate and differentiate. Better control of primitive cells is needed to extend the time and range of manipulation of such cells. A recently identified plant lectin Flt3 receptor-interacting lectin (FRIL) present may a special ability to preserve primitive CB progenitors for extended periods in culture without exogenous cytokines. But the mechanisms of FRIL preserving quiescent primitive cells are still unknown. Recently a novel protein HTm4 and its alternatively spliced variant HTm4S, which serve as hematopoietic cell cycle regulators, have been identified. In this report we studied the effect of FRIL on the in vitro maintenance of quiescent human cord blood stem cells and the expression of the novel hematopoietic cell cycle regulator HTm4 and HTm4S in progenitor cells cultured in FRIL. We analyzed the proliferation and the HPP-CFC proportion of CD34(+) cells treated with FRIL. The human HTm4 and HTm4S mRNA expression was detected by semi-quantitative RT-PCR, and the cell cycle status of CB CD34(+) cells was analyzed by FACS. The results showed that incubation of CD34(+) cells in FRIL resulted in a low proliferation of progenitor cells and fewer cycling cells, but FRIL selectively maintained a higher number of primitive cells with proliferative potential in suspension culture. CB CD34(+) cells cultured in FRIL showed significant diversity in the expression of HTm4 and HTm4S during 0~14 d. On d 0, HTm4 was detected at high level, downregulated on d 1, but upregulated during d 3 to d 14, and reaching the highest level on d 7. But the expression levels of HTm4S changed little in the cells cultured in FRIL except the obviously increased expression on d 7. Exogenous expression showed that HTm4 was localized around the karyon while HTm4S scatted in the cytoplasm, respectively, which may be responsible for their difference in function. Thus, FRIL can preserve quiescent primitive CD34(+), and FRIL's ability to preserve quiescent primitive cells in a reversible manner may significantly expand the time and range of ex vivo manipulations of human stem cells for clinical applications. In other words, HTm4 and HTm4S may play a crucial role in the cell cycle modulation of CD34(+) progenitor cells maintained with FRIL in vitro.

Antigens, CD20↗
PubMed2004

Potential efficacy of p16 gene therapy for EBV-positive nasopharyngeal carcinoma.

The p16 cell cycle inhibitory gene is a potentially critical molecular abnormality in nasopharyngeal carcinoma (NPC). Its expression is silenced through either deletion or promoter methylation in the vast majority of NPC. This in turn is associated with absent or reduced protein expression, which has been previously demonstrated by our group to correlate with inferior clinical outcome. Therefore, we were interested in evaluating the potential of adenoviral mediated p16 gene therapy (adv.p16) in an EBV-positive NPC model (C666-1). We confirm that under basal conditions, p16 protein is undetectable in C666-1 cells, which, in turn, is associated with retention of retinoblastoma protein (pRb) expression. P16 expression was observed as early as 4 hr after infection of C666-1 cells with adv.p16 (10 pfu/cell) with no discernible perturbation in pRb for up to 24 hr. At 48 hr post-infection, p16 expression continued to increase, but at this point, pRb expression started to decline significantly. Cell viability decreased in a dose-dependent manner, down to 20% using 50 pfu/cell of adv.p16. The addition of radiation therapy (RT) administered 24 hr post-infection achieved only a slightly additive cytotoxicity. Adv.p16 therapy resulted in multiple mechanisms of cytotoxicity, including cell cycle arrest at the G0/G1 phase, induction of senescence, along with apoptosis. Ex vivo infection of C666-1 cells with adv.p16 (25 pfu/cell) with subsequent implantation into scid mice completely prevented tumor formation, followed for up to 51 days. Our study demonstrates the potential efficacy of adv.p16 gene therapy for NPC, mediated through multimodal mechanisms of cytotoxicity. Future evaluations will examine strategies to increase in vivo tumor transduction with a view towards future clinical applications.

Adenoviridae↗
PubMed2004

Heterochromatin and tri-methylated lysine 20 of histone H4 in animals.

Tri-methylated lysine 20 on histone H4 (Me(3)K20H4) is a marker of constitutive heterochromatin in murine interphase and metaphase cells. Heterochromatin marked by Me(3)K20H4 replicates late during S phase of the cell cycle. Serum starvation increases the number of cells that exhibit high levels of Me(3)K20H4 at constitutive heterochromatin. Me(3)K20H4 is also present at the centromeric heterochromatin of most meiotic chromosomes during spermatogenesis and at the pseudoautosomal region, as well as at some telomeres. It is not present on the XY-body. During murine embryogenesis the maternal pronucleus contains Me(3)K20H4; Me(3)K20H4 is absent from the paternal pronucleus. On Drosophila polytene chromosomes Me(3)K20H4 is present in a 'punctate pattern' at many chromosomal bands, including the chromocenter. In coccids it is present on the facultatively heterochromatinised paternal chromosome set. We also present evidence that Me(3)K20H4 is dependent upon H3-specific Suv(3)9 histone methyltransferase activity, suggesting that there may be 'epigenetic cross-talk' between histones H3 and H4.

Animals↗
PubMed2004

Design and synthesis of 3d-4f metal-based zeolite-type materials with a 3D nanotubular structure encapsulated "water" pipe.

A nanotubular 3D heterometallic zeolitic polymer, {[Yb(PDA)3Mn1.5(H2O)3].1.5H2O}n (2), was designed and synthesized by simply tuning the amount of coordinated water on the Mn ion in the molecular ladder polymer {[Yb(PDA)3Mn1.5(H2O)6].6H2O}n (1). 1 and 2 were structurally and magnetically characterized. The water molecules capsulated within the nanotube were arrayed into an unprecedented "water" pipe. The robust 2 retained intact networks after the removal of guest water trapped in the nanotubes and even after methanol replaced guest water.

Journal Article↗