Biomedical subjects

Yi Shi

Publications and source records attributed to Yi Shi.

At least 37 records · Page 2Linked to original sources

PubMed2005

Inhibition of genes expression of SARS coronavirus by synthetic small interfering RNAs.

RNA interference (RNAi) is triggered by the presence of a double-stranded RNA (dsRNA), and results in the silencing of homologous gene expression through the specific degradation of an mRNA containing the same sequence. dsRNA-mediated RNAi can be used in a wide variety of eucaryotes to induce the sequence-specific inhibition of gene expression. Synthetic 21-23 nucleotide (nt) small interfering RNA (siRNA) with 2 nt 3' overhangs was recently found to mediate efficient sequence-specific mRNA degradation in mammalian cells. Here, we studied the effects of synthetic siRNA duplexes targeted to SARS coronavirus structural proteins E, M, and N in a cell culture system. Among total 26 siRNA duplexes, we obtained 3 siRNA duplexes which could sequence-specifically reduce target genes expression over 80% at the concentration of 60 nM in Vero E6 cells. The downregulation effect was in correlation with the concentrations of the siRNA duplexes in a range of 0 approximately 60 nM. Our results also showed that many inactive siRNA duplexes may be brought to life simply by unpairing the 5'end of the antisense strands. Results suggest that siRNA is capable of inhibiting SARS coronavirus genes expression and thus may be a new therapeutic strategy for treatment of SARS.

Animals↗

PubMed2005

Methane (CH4) emission from a natural wetland of northern China.

This article focuses on the seasonal and spatial changes of CH4 emission from the natural reed marsh of Liaohe Delta, China. Field experiments showed that this natural wetland acts as a CH4 sink in spring (-30 approximately -1000 microg/m2 x h), a strong source in summer (400-3000 microg/m2 x h) and a weak source in autumn (< 400 microg/m2 x h). Reed plants play an important role in transportation and emission of methane produced in soil. According to our field measurement data, CH4 emission is positively related to temperature, and negatively related to Eh value and water depth. The activity of methanogenic bacteria is higher in the rhizosphere and surface layer, and thus contributes more in CH4 emission than other layers.

China↗

PubMed2005

Prevalence, characteristics, and outcome of BK virus nephropathy in Japanese renal transplant patients: analysis in protocol and episode biopsies.

BACKGROUND: BK virus nephropathy (BKN) is recognized as a cause of graft loss in renal transplant patients. This may be related to the introduction of new and potent immunosuppressive regimens. In Japan, our experience regarding its prevalence, clinical significance, and outcome is still limited. In this study, our primary purpose is to outline the prevalence, outcome, and clinical characteristics of BKN as observed at Osaka University Hospital. METHODS: We retrospectively analyzed 112 biopsy specimens from 87 renal transplant patients. All transplantations were from living donors. Of the 112 biopsy specimens, 71 were from protocol biopsies and 41 were from episode biopsies. Calcineurin inhibitors and corticosteroid were used in all patients (tacrolimus 32 and cyclosporin 55). In addition, azathioprine was used in 43 patients, mizoribine was used in 24 patients, and mycophenolate mofetil was used in 20 patients. BKN was diagnosed by light microscopic examination and a positive immunohistochemical staining of anti-SV40 antibody in a biopsy specimen. In order to investigate the outcome and potential risk factors of patients with different histological staging, we divided the patients into groups A (mild histological change) and B (moderate or severe histological change). RESULTS: Of the 87 patients, six were diagnosed with BKN. There were no significant differences between BKN patients and non-BKN patients, except for the number of patients with graft loss (p < 0.001). Of the six BKN patients, three were in group A, and three were in group B. We recognized a significant difference between group A and group B in terms of anti-rejection treatment including glucocorticoid, tacrolimus trough levels of over 8 ng/mL, episode of acute rejection within 1-month post-transplantation, and the time period between transplantation and BKN diagnosis. CONCLUSIONS: This is the first report of BKN in Japanese renal allograft recipients. In our hospital, the prevalence, risk factors, and outcome were similar to those previously for non-Japanese recipients.

Adult↗

PubMed2005

Long term efficacy of simvastatin in renal transplant recipients treated with cyclosporine or tacrolimus.

BACKGROUND: Hyperlipidemia is frequently developed following renal transplantation and results in worsening of the patient's prognosis. METHODS: In this study, 14 patients who had hypercholesterolemia [total cholesterol (TC) >200 mg/dL] and hypertriglyceridemia [triglyceride (TG) >150 mg/dL] 1 month after renal transplantation (post-transplantation), seven patients each under the treatment with immunosuppressant, either cyclosporine or tacrolimus started simvastatin treatment of 5-10 mg/d and continued the treatment for 4 yr. The effect of simvastatin treatment was assessed by comparison in serum lipid levels (TC, TG, cholesterol in lipoprotein fractions, and apolipoproteins) and the lipid metabolism related enzyme activities for post-transplantation, after 6-month and 4-yr simvastatin treatment. RESULTS: Simvastatin treatment of 4 yr significantly decreased the elevated levels of serum TC from 234.5 +/- 30.8 to 186.3 +/- 20.5 mg/dL (p < 0.001), low density lipoprotein cholesterol (LDL-C) from 116.7 +/- 22.5 to 82.7 +/- 16.6 mg/dL (p < 0.05) and TG from 200.3 +/- 109.2 to 97.0 +/- 45.2 mg/dL (p < 0.001). In addition, there were significant decreases in elevated serum very-low-density lipoprotein cholesterol (VLDL-C) from 47.8 +/- 18.4 to 28.6 +/- 9.5 mg/dL (p < 0.001) and LDL2 cholesterol (LDL2-C) from 20.8 +/- 8.2 to 5.7 +/- 1.8 mg/dL (p < 0.001). CONCLUSION: The results indicate that 4-yr treatment of simvastatin improves profiles of the atherogenic lipids in renal transplant patients with immunosuppressant caused hypercholesterolemia and hypertriglyceridemia treated either cyclosporine or tacrolimus in similar manner.

Adult↗

PubMed2005

Establishment of a screening system for selection of siRNA target sites directed against hepatitis B virus surface gene.

To study the inhibitory effects of plasmid-derived small interfering RNA (siRNA) and synthetic siRNA on the expression of the hepatitis B virus surface (HBs) gene, three plasmid-derived siRNAs and one synthetic siRNA that complement the coding region of the HBs gene were prepared. The HBs expression plasmid pHBs-EGFP was also constructed. HeLa cells were co-transfected with pHBs-EGFP and the above siRNAs. The HBs mRNA quantities were measured by reverse-transcription PCR, and the level of HBs-EGFP fusion protein was quantified by fluorescent microscope. The concentrations of the hepatitis B virus surface antigen (HBsAg) derived from the culture supernatant of transfected HepG2.2.15 cells were measured by an enzyme-linked immunosorbent assay (ELISA) kit. The results showed that the three plasmid-derived siRNAs and the synthetic siRNA can effectively reduce the quantities of HBs mRNA and protein. The plasmid-derived siRNA psiRNA1 was found to be the most effective inhibitor of HBs expression. It can inhibit HBs-EGFP expression by 63.3% and suppress HBs mRNA by 75.6%. To further substantiate the above observations, psiRNA1 was transfected into HepG2.2.15 cells (an HBV secreting cell line). The transfections resulted in almost complete blockage of HBsAg production, whereas control vector-transfected cells secreted high levels of HBsAg 7 days post-transfection. In conclusion, our data suggests that RNA interference (RNAi) is an efficient approach for reducing the level of HBs transcripts and proteins and for suppressing HBsAg production.

Base Sequence↗

PubMed2005

Dose-dependent inhibition of gynecophoral canal protein gene expression in vitro in the schistosome (Schistosoma japonicum) by RNA interference.

The gynecophoral canal protein gene SjGCP of Schistosoma japonicum that is necessary for the pairing between the male and female worms is specifically expressed in the adult male worm. This protein is widely distributed in the adult female worm after pairing. Reverse transcription-polymerase chain reaction (RT-PCR) and immunofluorescence were employed to analyze the relationship between the RNAi effect and dsRNA dosage in the parasites. The results revealed that the inhibition of SjGCP expression by siRNA is dose-dependent. RT-PCR analysis showed that the SjGCP transcript level was reduced by 75% when 100 nM dsRNA was applied.

Animals↗

PubMed2005

Vitamin k epoxide reductase: a protein involved in angiogenesis.

Vitamin K epoxide reductase (VKOR) is a newly identified protein which has been reported to convert the epoxide of vitamin K back to vitamin K, a cofactor essential for the posttranslational gamma-carboxylation of several blood coagulation factors. We found that the gene is expressed ubiquitously including vascular endothelial cells, smooth muscle cells, fibroblasts and cardiomyocytes, and is overexpressed in 11 tumor tissues on microarray. Stable transfection of VKOR cDNA into tumor cell line A549 and H7402 did not promote the cell proliferation. These results promoted us to hypothesize that VKOR may also be involved in angiogenesis. To test this hypothesis, the expression of VKOR was studied in different vascular cells in developmental and pathologic heart tissues. The effects of overexpression and suppressing expression of VKOR on endothelial cell proliferation, migration, adhesion, and tubular network formation were explored. We found that VKOR expression in arteries was prominent in vascular endothelial cells and was high in the ventricular aneurysm tissue of human heart and human fetal heart. In vitro studies showed that overexpression of VKOR slightly but significantly stimulated human umbilical vein endothelial cell proliferation (by 120%), migration (by 118%), adhesion (by 117%), as well as tubular network formation. Antisense to VKOR gene inhibited the proliferation (by 67%), migration (by 64%), adhesion (by 50%), and tubular network formation. Our findings support the impact of VKOR in the process of angiogenesis; hence, the molecule may have a potential application in cardiovascular disease and cancer therapy.

Adenoviridae↗

PubMed2005

Lipoprotein-associated phospholipase A2: a novel marker of cardiovascular risk and potential therapeutic target.

Although the clinical benefit of statins is well established, these agents reduce the risk of cardiovascular events by only 20 - 40%, and the residual risk for high-risk patients is considerable. The recognition of atherosclerosis as an inflammatory disease has opened the door to numerous complementary therapeutic approaches to further reduce risk and the overall burden of cardiovascular disease. Lipoprotein-associated phospholipase A(2) (Lp-PLA(2)) is a novel inflammatory marker of cardiovascular risk that is being evaluated as a potential therapeutic target. The biological function of this enzyme in atherosclerosis has been controversial but recent evidence supports its pro-atherogenic role. The enzyme is predominantly bound to low-density lipoprotein cholesterol particles in humans, and its activity produces bioactive lipid mediators that promote inflammatory processes present at every stage of atherogenesis, from atheroma initiation to plaque destabilisation and rupture. Initial clinical studies suggest that the inhibitors of Lp-PLA(2) can block enzyme activity in plasma and within atherosclerotic plaques. However, more studies are needed to determine the potential clinical benefits of inhibiting Lp-PLA(2).

1-Alkyl-2-acetylglycerophosphocholine Esterase↗

PubMed2005

Current advances in sustained-release systems for parenteral drug delivery.

Major progresses in the development of parenteral sustained-release systems have been made in recent years as evidenced by the regulatory approval and market launch of several new products. Both the availability of novel carrier materials and the advances in method of fabrication have contributed to these commercial successes. With the formulation challenges associated with biologics, new delivery systems have also been evolved specifically to address the unmet needs in the parenteral sustained release of proteins. In this review paper, different new carriers systems and preparation methods are discussed with special focus on their applications to biologicals.

Animals↗

PubMed2005

[Expression of toll-like receptor mRNA in lung tissue in mice with hemorrhagic shock].

OBJECTIVE: To investigate the influence and its significance of expression of Toll-like receptor mRNA in lung tissue of mice with hemorrhagic shock without resuscitation. METHODS: Forty-five C57BL/6 mice were randomly divided into hemorrhagic shock group, lipopolysaccharide (LPS) group (positive control, 5 mg/kg LPS was injected into caudal vein), and sham-operation group (negative control), with 15 mice in each group. The hemorrhagic shock model was reproduced by heart puncture. The total RNA from lung tissue of mice in each group was extracted by Tripure reagent and the expression of Toll-like receptor 2 (TLR2) and TLR4 mRNA were measured by semi-quantitative reverse transcription-polymerase chain reaction. RESULTS: Hemorrhagic shock and LPS challenge increased lung neutrophil infiltration and erythrocyte diapedesis. The expression of TLR2 mRNA and TLR4 mRNA could be found in normal lung tissues, but they were increased at 0, 1, 2, 4, and 6 hours after hemorrhagic shock and LPS challenge. There was no change in the sham-operation group. CONCLUSION: The increased expression of TLR2 and TLR4 gene in lung tissue after hemorrhagic shock is closely correlated with the onset of acute lung injury. Though the innate immunity is enhanced, the animals are more susceptible to subsequent irritations. Over-expression of TLR2 and TLR4 may induce structural and functional damage to organs.

Animals↗

PubMed2005

[Inhibition of mouse hepatocyte apoptosis by anti-caspase-12 small interfering RNA].

OBJECTIVES: To study the inhibition of primary mouse hepatocyte apoptosis by small interfering RNA (siRNAs) against caspase-12. METHODS: The Balb/c mouse primary hepatocytes were isolated in situ with two-step liver perfusion with 0.5 g/L collagenase type IV, and apoptosis were induced with 4 micromol/L thapsigargin (TG). The three kingds of siRNAs targeting different gene sites (130, 214, 521) were synthetized chemically. The single-stranded RNAs were annealed to produce double-stranded siRNAs, then the mouse primary hepatocytes were transfected by oligofectamine package. The inhibition of caspase-12 was analyzed with RT-PCR and Western-blot. The viable hepatocytes following the induction of apoptosis were evaluated with MTT. RESULTS: All the three kinds of siRNAs could obviously inhibit normal mouse hepatocyte caspase-12 mRNA. The siRNA (214) were more effective than the other two when the concentration was 100 nmol/L. The caspase-12 mRNA expression was inhibited by 52.08%, while that of siRNA (521) was 30.73% (t=4.30, P <0.05). However when the concentration was 200 nmol/L, the inhibitions were similar (88.07%, 86.22% and 89.41% respectively). siRNA (214) could downregulate the expression of apoptotic hepatocytes procaspase-12 by 51.43% ( t=4.30, P <0.01). Contrasted with apoptotic hepatocytes, the cell activity, which was analyzed with MTT, increased by 48.76% (t=2.23, P <0.01). CONCLUSION: siRNAs could effectively downregulate the expression of caspase-12 at mRNA and protein levels and prevent mouse primary hepatocytes from apoptosis.

Animals↗

PubMed2005

[Systematic review and meta-analysis on the integrative traditional Chinese and Western medicine in treating SARS].

OBJECTIVE: To systematically evaluate the effects of Chinese herbal medicine in treating severe acute respiratory syndrome (SARS). METHODS: Electronic and manual searches was conducted to identify randomised controlled trials (RCTs) for comparing the effects of integrative traditional Chinese and Western medicine versus the effects of Western medicine alone in treating SARS. Methodological quality of trials was assessed in terms of generation of allocation sequence, allocation concealment, blinding, and intention-to-treat. Exploring analysis was carried out on the non-randomized clinical controlled studies. Two authors collected data independently and evaluated quality and results. The data were quantified by Meta-analysis. RESULTS: Eight RCTs (488 SARS patients) were included. The methodological quality was generally low. Results of Meta-analysis showed that the integrative therapy could significantly reduce the mortality (relative risk 0.32 [95% CI 0.12 - 0.91]) and the occurrence of fungal infection in patients who received hormone (glucocorticoid) therapy (0.35: 0.14 - 0.90), shorten the duration of fever (weighted mean difference -0.83 day; -1.30 - -0.35) and symptom relieving time (-1.23; -2.09 - -0.37), reduce the persistent time of chest radiograph abnormalities (- 2.61; -3.74 - -1.49). But it showed no significant difference on quality of life or glucocorticoid dosage. Conclusion The integrative therapy may have beneficial effects in lowering mortality, reducing complications, shortening the duration of symptoms and fever existence and lessening pulmonary inflammation in SARS patients. The evidence is insufficient to come to the affirmative conclusion due to the low methodological quality of the included trials.

Adolescent↗

PubMed2004

Mycophenolate mofetil prevents autoimmune glomerulonephritis and alterations of intrarenal adrenomedullin in rats.

We studied the effects of mycophenolate mofetil, a specific inhibitor of inosine monophosphate dehydrogenase, on the mercuric chloride induced autoimmune glomerulonephritis in Brown Norway rats and also on the renal contents of adrenomedullin. In the rats with autoimmune glomerulonephritis, plasma and renal tissue adrenomedullin levels were increased significantly. Coadministration of mycophenolate mofetil resulted in prevention of autoimmune glomerulonephritis and also in maintaining of plasma and renal tissue adrenomedullin levels at control levels. Adrenomedullin mRNA expressions in the renal cortex were also higher in the rats with autoimmune glomerulonephritis. Significant positive correlations were found between renal cortical adrenomedullin levels and urinary Na+ and N-acetyl-beta-D-glucosaminidase excretion. A significant negative correlation between renal cortical adrenomedullin levels and creatinine clearance was also found. These results suggest that mycophenolate mofetil suppresses the renal damage in rats with autoimmune glomerulonephritis and renal adrenomedullin may participate in the pathophysiology of autoimmune glomerulonephritis.

Adrenomedullin↗

PubMed2004

Chinese herbal medicine for severe acute respiratory syndrome: a systematic review and meta-analysis.

OBJECTIVES: To review randomized controlled trials (RCTs) evaluating the effects of Chinese herbal medicine for treating severe acute respiratory syndrome (SARS) systematically. DESIGN: Electronic and manual searches identified RCTs comparing Chinese medicine integrated to conventional medicine versus conventional medicine alone. Methodological quality of trials was assessed by generation of allocation sequence, allocation concealment, blinding, and intention-to-treat. RESULTS: Eight RCTs (488 patients with SARS) were included. The methodological quality was generally low. The combined therapy showed significant reduction of mortality (relative risk 0.32 [95% confidence interval {CI} 0.12 to 0.91]), shortened duration of fever, symptom relief, reductions in chest radiograph abnormalities, and reductions in secondary fungal infections among patients receiving glucocorticoids. There were no significant effects on quality of life or glucocorticoid dosage. CONCLUSION: Chinese herbal medicine combined with conventional medicine may have beneficial effects in patients with SARS. The evidence is insufficient because of the low methodological quality of the included trials.

Drug Therapy, Combination↗

PubMed2004

Direct transfer of hepatocyte growth factor gene into kidney suppresses cyclosporin A nephrotoxicity in rats.

BACKGROUND: The clinical utility of cyclosporin A (CsA) has been limited by its nephrotoxicity, which is characterized by tubular atrophy, interstitial fibrosis and progressive renal impairment. Hepatocyte growth factor (HGF), which plays diverse roles in the regeneration of the kidney following acute renal failure, has been reported to protect against and salvage renal injury by acting as a renotropic and anti-fibrotic factor. Here, we investigated protective effects of HGF gene therapy on CsA-induced nephrotoxicity by using an electroporation-mediated gene transfer method. METHODS: CsA was orally administered as a daily dose of 30 mg/kg in male Sprague-Dawley rats receiving a low sodium diet (0.03% sodium). Plasmid vector encoding HGF (200 micro g) was transferred into the kidney by electroporation. RESULTS: HGF gene transfer resulted in significant increases in plasma HGF levels. Morphological assessment revealed that HGF gene transfer reduced CsA-induced initial tubular injury and inhibited interstitial infiltration of ED-1-positive macrophages. In addition, northern blot analysis demonstrated that cortical mRNA levels of TGF-beta and type I collagen were suppressed in the HGF group. Finally, HGF gene transfer significantly reduced striped interstitial phenotypic alterations and fibrosis in CsA-treated rats, as assessed by alpha-smooth muscle actin expression and Masson's trichrome staining. CONCLUSIONS: These results suggest that HGF may prevent CsA-induced tubulointerstitial fibrosis, indicating that HGF gene transfer may provide a potential strategy for preventing renal fibrosis.

Animals↗

PubMed2004

Genome-wide search for type 2 diabetes/impaired glucose homeostasis susceptibility genes in the Chinese: significant linkage to chromosome 6q21-q23 and chromosome 1q21-q24.

This genome-wide search for susceptibility genes to type 2 diabetes/impaired glucose homeostasis (IGH) was performed on a relatively homogeneous Chinese sample with a total number of 257 pedigrees and 385 affected sibpairs. Two regions showed significant linkage to type 2 diabetes/IGH in the Chinese. The region showing linkage to type 2 diabetes/IGH from the entire sample group analysis was located on chromosome 6q21-q23 (128.93 cM, 1-LOD [logarithm of odds] support interval between 124 and 142 cM, according to the Marshfield genetic map), with a maximum likelihood score of 6.23, a nonparametric linkage (all) score of 4.48, and empirical P value <0.001. With a subanalysis based on 101 affected sibpairs with age at diagnosis of type 2 diabetes/IGH <40 years, we detected significant evidence for linkage to chromosome 1q21-q24 (192.1 cM, 1-LOD support interval between 182 and 197 cM), with a maximum likelihood score of 8.91, a nonparametric linkage (all) score of 5.70, and empirical P value <0.001. No interaction was observed between these two regions. Our independent replication of the region on chromosome 1q that has been shown to be linked significantly to type 2 diabetes/IGH in Chinese supports the notion that gene(s) in this region may be universally important in the development of human type 2 diabetes.

Asian People↗

PubMed2004

[Effect of small interfering RNA targeting connective tissue growth factor on the synthesis and secretion of extracellular matrix in hepatic stellate cells].

OBJECTIVE: To investigate the effect of chemically synthetic small interfering RNA (siRNA) targeting connective tissue growth factor (CTGF) on the synthesis and secretion of extracellular matrix (ECM) in hepatic stellate cells (HSC). METHODS: Chemically synthetic siRNA targeting CTGF was transfected into HSC T6 (an active HSC line in rats) by oligofectamine package, and untreated HSC T6 were used as control. Total RNA and protein of the cells, after their incubation with siRNA for 24, 48 and 72 hours, were extracted, and the supernatants were collected. The expressions of CTGF and type I and III collagen genes were detected by means of reverse transcription-polymerase chain reaction (RT-PCR) and/or Western blot. Contents of hyaluronic acid and type III pro-collagen in the supernatants were determined by radioimmunoassay. RESULTS: The expression of CTGF at mRNA and protein level and type I and III collagen at mRNA levels were markedly down-regulated in siRNA-transfected HSCs. The contents of hyaluronic acid and type III pro-collagen in the supernatants decreased by 46%+/-7%, 52%+/-7%, 53%+/-7% and 29%+/-18%, 29%+/-7%, 27%+/-5%, compared with those of the blank control at 24, 48 and 72 hours. CONCLUSIONS: Chemically synthetic anti-CTGF siRNA can significantly inhibit CTGF gene expression in HSC, and markedly reduce the synthesis and secretion of ECM including type I and III collagen and hyaluronic acid. The siRNA-directed suppression of CTGF gene in HSC was maintained for 72 hours. This suggests that chemically synthetic siRNA may be a potential in preventing and treating liver fibrosis and may have a promising future for development

Cell Line↗

PubMed2004

[Effects of free-air CO2 enrichment (FACE) on soil microbial biomass under rice-wheat rotation].

The effect of CO2 enrichment on soil microbial biomass in 0-5 cm and 5-10 cm soil layers under rice-wheat rotation was studied under the conditions of routine cultivation, irrigation and fertilization. The results showed that FACE treatment could significantly increase the amount of soil bacteria in 0-5 cm and 5-10 cm soil layers during rice jointing stage and wheat wintering and ripening stages. Elevated CO2 only significantly increased the amount of soil fungi in 0-5 cm soil layer during rice ripening stage. During the whole period of rotation, the amount of soil bacteria was greater than that of soil fungi.

Air↗