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Biomedical subjects

Zhi Zhou

Publications and source records attributed to Zhi Zhou.

At least 19 recordsLinked to original sources
PubMed2006

Involvement of DDAH/ADMA/NOS pathway in nicotine-induced endothelial dysfunction.

Asymmetric dimethylarginine (ADMA), an endogenous nitric oxide synthase (NOS) inhibitor, is a key contributor for endothelial dysfunction. Decrease in activity of dimethylarginine dimethylaminohydrolase (DDAH), a major hydrolase of ADMA, causes accumulation of ADMA under cardiovascular abnormalities. The study was to determine whether nicotine-induced endothelial dysfunction is related to modulating DDAH/ADMA/NOS pathway. Four-week oral nicotine treatment (5 mg/kg/day) significantly increased the plasma level of ADMA and decreased aortic DDAH expression as well as impaired endothelial function in Sprague-Dawley rats. Similarly, the medium levels of both ADMA and lactate dehydrogenase were markedly elevated in umbilical vein endothelial cells (HUVECs) treated with nicotine (10 microM) for 48 h. Nicotine-induced endothelial damages were markedly attenuated by L-arginine or overexpression of DDAH-II. Nicotine greatly downregulated both mRNA and protein levels of DDAH-II, and decreased DDAH activity in HUVECs. HUVECs express alpha7 nicotinic acetylcholine receptor (alpha7 nAChR), whose antagonists could block these effects of nicotine mentioned above. Intracellular Ca2+ chelator did not affect nicotine-induced decrease in DDAH-II mRNA level. In conclusion, nicotine modulates DDAH/ADMA/NOS pathway of endothelial cell via activation of alpha7 nAChR, which may be involved in endothelial dysfunction associated to smoking.

Amidohydrolases↗
PubMed2006

SARS-CoV nucleocapsid protein binds to hUbc9, a ubiquitin conjugating enzyme of the sumoylation system.

SARS-CoV is a newly identified coronavirus (CoV) that causes severe acute respiratory syndrome (SARS). The SARS-CoV nucleocapsid (N) protein is an important structural and functional protein. To identify cellular proteins that interact with the SARS-CoV N protein and to elucidate the possible involvement of N protein in SARS-CoV pathogenesis, a human lymphocyte cDNA library was screened using a yeast two-hybrid system assay. hUbc9, a ubiquitin conjugating enzyme of sumoylation system, was found to interact specifically with the N protein, implying the post-translational sumoylation of the N protein. Mapping studies localized the critical N sequences for this interaction to amino acids 170-210, which includes the SR-rich motif. However, the consensus motif of sumoylation GK(62)EE in the N protein is not responsible for binding to hUbc9. Mutations of hUbc9 at the enzyme active site C93A or C93S severely impair the interaction with the N protein. The two proteins were also shown to colocalize in the cytoplasm of the transfected 293T cells. This is the first report demonstrating the interaction of hUbc9 with a structural protein of plus-strand RNA viruses, indicating a new drug target for SARS-CoV.

Binding Sites↗
PubMed2006

Halftone visual cryptography.

Visual cryptography encodes a secret binary image (SI) into n shares of random binary patterns. If the shares are xeroxed onto transparencies, the secret image can be visually decoded by superimposing a qualified subset of transparencies, but no secret information can be obtained from the superposition of a forbidden subset. The binary patterns of the n shares, however, have no visual meaning and hinder the objectives of visual cryptography. Extended visual cryptography [1] was proposed recently to construct meaningful binary images as shares using hypergraph colourings, but the visual quality is poor. In this paper, a novel technique named halftone visual cryptography is proposed to achieve visual cryptography via halftoning. Based on the blue-noise dithering principles, the proposed method utilizes the void and cluster algorithm [2] to encode a secret binary image into n halftone shares (images) carrying significant visual information. The simulation shows that the visual quality of the obtained halftone shares are observably better than that attained by any available visual cryptography method known to date.

Algorithms↗
PubMed2005

[Expression of HoxA10 in acute leukemia and its significance].

To investigate the expression of HoxA(10) mRNA in acute leukemia patients and its significance, HoxA(10) level was detected by reverse transcription polymerase chain reaction (RT-PCR) in 50 patients with acute leukemias, 7 healthy volunteers and 3 patients with ITP (idiopathic thrombocytopenic purpura). The regularity of the expression of HoxA(10) gene in acute leukemia and the relationship between HoxA(10) level and the prognosis of leukemia was explored. The results showed that HoxA(10) was expressed in all types of acute myelogenous leukemia; HoxA(10) message was also observed in acute lymphoblastic leukemia patients and part of control groups. 3 normal donors were found not to express HoxA(10). The level of HoxA(10) mRNA of acute myelogenous leukemia patients was significantly higher than that of acute lymphoblastic leukemia patients and controls (P < 0.01). HoxA(10) gene appeared to be more strongly expressed in AML-M(1) and -M(2) subtypes than in AML-M(4) and -M(5) subtypes, and the gene was notable high expressed in acute promyelocytic leukemia. The number of blast and promyeloid cells in the bone marrow was positive related with the level of HoxA (r = 0.635, P < 0.01). The level of HoxA(10) of 9 non-responsive patients was higher than that of 8 remission patients, but there was no significant difference between them (P = 0.258). HoxA(10) was overexpressed in acute myelogenous leukemia. It is concluded that HoxA(10) is a major transcription factor regulating hematopoiesis and a mark to differentiate lymphoid leukemia and myelogenous leukemia, but not a specific gene of cancer. The level of HoxA(10) is related with load of leukemic cells and curative effect, and can affect occurrence and development of leukemia in combination with many cytokines, HoxA(10) may facilitate the leukemia progression with another cofactors.

Adolescent↗
PubMed2004

[Etiology and clinical characters of hepatitis caused by non-hepatotropic virus].

OBJECTIVE: To explore the etiology and clinical characters of hepatitis caused by non-hepatotropic virus. METHODS: 68 non-hepatotrophic viral hepatitis patients with negative anti-HAV-anti-HEV were diagnosed by detecting antibodies of anti-HSV IgM, anti-EBV IgM, anti-CMV IgM, anti-CSV IgM and anti-ANA, anti-mitochondrion antibody. Their clinical symptoms and signs were compared with that of acute viral hepatitis patients at the same time. RESULTS: Among the 68 patients, 9 were infected by HSV, 12 by EBV, 8 by CMV, 14 by CSV, and the other 13 patients and 12 patients were positive for anti-ANA and anti-mitochondrion antibody, respectively. 35 of 43 non-hepatotrophic viral hepatitis patients were infected in winter and spring season. Their clinical symptoms and signs were milder than that of acute viral hepatitis patients. CONCLUSION: Liver damage and dysfunction may be the prominent phenomenon during HSV, EBV, CMV and CSV infection, just like that of acute viral hepatitis but with milder clinical symptom and signs.

Adult↗
PubMed2004

[The efficacy of two type of membrane plasma separator on the treatment of patients with chronic severe hepatitis B].

OBJECTIVE: In order to compare the efficacy of two kinds of membrane plasma separator on the treatment of patients with severe hepatitis B. METHODS: 63 cases suffering from chronic severe hepatitis B were divided into two groups, 25 cases were treated with plasma exchange using Evacure-4A membrane plasma separator (A group) or 38 cases were using PS-06 membrane plasma separator (B group). Both of them also were treated with similar basic medical treatment. The level of serum total bilirubin, non-conjugated bilirubin, prothrombin time and albumin were tested at baseline and the end of the treatment with PE. RESULTS: Evacure-4A and PS-06 membrane plasma separators can effientively remove bilirubin, the levels of serum total bilirubin, non-conjugated bilirubin of all patients were significantly decreased after treated with PE. In A group, the level of serum total bilirubin, non-conjugated bilirubin decreased from (464.2+/-193.8)micromol/L to (279.4+/-158.7)micromol/L, (293.5+/-129.1)micromol/L to (175.5+/-106.7)micromol/L (t=5.45, 10.36, P<0.01) respectively. In B group, the level of serum total bilirubin, non-conjugated bilirubin decreased from (493.2+/-126.9)micromol/L to (299.7+/-96.5)micromol/L, (300.2+/-74.3)micromol/L to (171.5+/-53.1)micromol/L (t=5.17, 12.04, P<0.01) respectively. The level of serum albumin increased after treated with PE in A and B groups, to contrast with PS-06, the increasing percentage of albumin was higher when the patients were treated with PE using Evacure-4A membrane plasma separator [(8.3+/-0.7) % vs. (3.4+/-9.3) %, t = 2.76, P<0.01]. CONCLUSION: Evacure-4A membrane plasma separator may be better than PS-06 membrane plasma separator on the treatment of patients with chronic severe hepatitis B.

Adult↗
PubMed2004

[The effect of artificial support system on serum cytokine in chronic severe hepatitis].

OBJECTIVE: To explore the changes of cytokines including TNFalpha, TGFbeta1 and nitrogen monoxide, and endotoxin in the serum of chronic severe hepatitis after the treatment of ALSS, and to evaluate further the value of ALSS in the treatment of chronic severe hepatitis. METHODS: Forty two patients were screened. The changes of TNFalpha, TGFbeta1, nitrogen monoxide and endotoxin were detected respectively. The relationship between the cytokines and the severity and prognosis were further analyzed. RESULTS: ALSS was effective to decrease the serum concentration of cytokines. TNFalpha dropped from (481.57+/-229.33) pg/ml to (156.46+/-78.12) pg/ml (P < 0.05). TGFbeta1 from (44.09+/-31.73) ng/ml to (27.77+/-23.28) ng/ml (P < 0.01), endotoxin from (1.05+/-0.37) Eu/ml to (0.28+/-0.22) Eu/ml (P < 0.001). NO from (71.15+/-33.09) micromol/L to (58.11+/-29.30) micromol/L (P < 0.001). Before the therapy endotoxin was related with TNFalpha and total bilirubin, while after the therapy, NO was related with protime and aminonemia. CONCLUSION: High level of endotoxin and nitrogen monoxide in serum plays an important role in hepatocyte damage of chronic severe hepatitis. The changes of serum endotoxin TNFalpha, TGFbeta1 and nitrogen monoxide level in patients with chronic severe hepatitis can be used to judge the severity and prognosis of severe hepatitis. ALSS is a reliable hepatic support device for chronic severe hepatitis

Adult↗
PubMed2004

[The difference between the positive rate of anti-HCV in the patients with severe viral hepatitis detected by the first generation or second generation enzyme linked-immunosorbent assay].

OBJECTIVE: To compare the positive rate of antibody to hepatitis C virus (anti-HCV) in sera of patients with severe viral hepatitis between 1984-1990 year and 1997-2003 year. METHODS: Serum anti-HCV was detected by enzyme linked-immunosorbent assay (ELISA). It was detected by the first generation (1st) ELISA (Ortho Co. USA) in 79 cases of severe viral hepatitis during 1984-1990 year, and it was detected by the second generation (2nd) ELISA (Xiamen Xingchuang Co. China) in 251 cases of severe viral hepatitis during 1997-2003 year. RESULTS: The positive rate of serum anti-HCV was 51.9% detected by the 1st ELISA in 79 cases of severe viral hepatitis during 1984-1990 year, and it was 1.2% detected by the 2nd ELISA in 251 cases of severe hepatitis during 1997-2003 year (chi2 = 133.68, P </= 0.001). CONCLUSION: To compare with the positive rate of serum antibody to hepatitis C virus in severe viral hepatitis detected by the 1st ELISA, it was lower that detected by the 2nd ELISA

Adult↗
PubMed2004

[Diagnosis and therapy of 186 spontaneous bacterial peritonitis patients with end-stage liver disease].

OBJECTIVE: To improve the diagnosis and treatment level of spontaneous bacterial peritonitis (SBP) in the patients with advanced liver disease, get better curative effect and prognosis. METHODS: Registered the body temperature, symptoms and signs in the abdomen, and blood routine test, the polymorphonuclear (PMN) cell count, and ascites culture in the patients with cirrhosis and fulminant hepatitis. These patients were given supporting therapies including use plasma and albumin as well as antibiotics treatment according to drug sensitivity or empiric. Changes of the body temperature, symptoms and signs were used to evaluate the effect of therapy. RESULTS: 186 of 275 inward patients with end-stage liver disease during this period were considered as SBP by ascites culture or clinical experience with various degree symptoms and signs such as pain, distention, higher tension and touch pain in the abdomen. Infective rate was 67.6%. Among them 138 patients had abnormal body temperature more than 37.4 degrees C. 106 patients with leukocyte count in the peripheral blood more than 10 x 10(9)/L; 137 patients with PMN more than 80% in differential cell count; 103 patients with PMN more than 250/mm(3) in ascites. Only 29 patients were culture positive. 82 patients were cured, 17 patients with improvement, 18 patients with inefficacy or deterioration. 42 patients died of hepatic-renal failure and 27 patients died because of upper alimentary tract bleeding, respectively. CONCLUSION: Signs and symptoms of SBP were atypical in the patients with end-stage liver disease. Ascites culture positive rate was not high. Early diagnosis and proper use antibiotics according to culture and empirics were important to increase effect and improve prognosis

Adolescent↗
PubMed2003

Chemical and biological regeneration of HDTMA-modified montmorillonite after sorption with phenol.

Hexadecyltrimethylammonium (HDTMA)-modified montmorillonite (HMM) has recently been recognized as a potential sorbentto remove organic contaminants from environmental systems. Potential applications of this material highly depend on the efficiency of regenerating contaminant-sorbing HMM. In this study, we investigated a chemical (NaOH solution) and a biological (yeast Pityrosporum sp.) method to regenerate phenol-sorbing HMM. Our results showed that the sorption coefficient of phenol to HMM is not a linear function of the ratio of the substitution of HDTMA in HMM. Chemical regeneration of HMMs (0-0.7 times of its cation exchange capacity (CEC)) proved the existence of a phenol residual amount of about 3 mg x g(-1) in the HMMs tested when aqueous pH is maintained above 11. In addition, the obvious deductions in the sorption capacity of the chemically regenerated HMMs were observed after four cycles of sorption-regeneration. However, the sorption capacities of intermediate substituted HMMs (0.3-0.7 CEC) can be completely restored by bioregeneration with yeast for extended cycles of reuse. The results imply that the bioregeneration method with yeast could be a promising technique for in-situ bioremediation of phenol-contaminated groundwater in the subsurface or for treatment of phenol containing wastewater.

Adsorption↗
PubMed2003

[One year and half treatment with lamivudine in active cirrhosis resulting from chronic hepatitis B].

OBJECTIVE: To study the therapy effect of long term lamivudine treatment on active cirrhosis following chronic hepatitis B, and explore the methods for abnormalities resulting from lamivudine withdrawing. METHODS: 58 patients received lamivudine 100 mg orally everyday for 18 months. The changes were observed and wrote down, including clinical symptoms and signs, aminotransferase, virology indexes, and the abnormalities after lamivudine withdrawing, then further to find out plans for the latter. RESULTS: (1) After lamivudine treatment, there were 35 patients whose situation stabilized, life quality improved, child-pugh score declined, and liver function turned better. (2) The level of HBV DNA decreased at least 10(3) copies/ml. HBeAg of 33.3% patients (13/39) became negative. (3) Among the 10 patients who stopped lamivudine of their own accord, and came again after 3 - 6 months because of hepatitis B recurring, two were treated with interferon for one month, then turning to liver-protecting methods for deteriorating, the other eight only received liver-protecting and immune-regulating treatment, whose liver function improved. CONCLUSIONS: Long term treatment with lamivudine for active cirrhosis following chronic hepatitis B can improve liver function and life quality, prevent exacerbation. And it is not advisable to use interferon for hepatitis B relapsing after lamivudine withdrawing.

Adult↗
PubMed2003

[Reciprocal priming-boosting role of HBsAg and DNA vaccines].

OBJECTIVE: To evoke more effective humoral and cell-mediated immunization against hepatitis B virus (HBV) infection. METHODS: HBsAg-primed mice were boosted with HBs-DNA vaccine, and HBs-DNA-primed mice were boosted with HBsAg vaccine. Anti-HBs level was assayed by ELISA and cytotoxic T lymphocyte (CTL) response was tested by lactic acid dehydrogenase (LDH) releasing method two weeks after the boosted immunization. RESULTS: Anti-HBs level and CTL responsive rate at the effector/target cell ratio of 100:1 were 0.38 and 36% in HBsAg/HBs-DNA vaccination group, 0.32 and 27% in HBs-DNA/HBsAg vaccination group, 0.48 and 1.5% in HBsAg/HBsAg vaccination group, 0.24 and 68% in HBs-DNA/HBs-DNA vaccination group, respectively. CONCLUSION: Priming with HBs-DNA vaccine followed by boosting with conventional HBsAg vaccine results in greater antibody response (F = 21.19, P < 0.05), and CTL response after HBsAg vaccination can be improved by boosting with HBs-DNA vaccine (F = 165.59, P < 0.05). It brings to better efficacy by combining HBsAg vaccine with HBs-DNA vaccine.

Animals↗
PubMed2003

[Effects of topical application of immunoglobulin yolk on mutans streptococci in dental plaque].

OBJECTIVE: To evaluate the inhibitory effects of topical application of specific immunoglobulin yolk antibodies (IgY) to mutans streptococci on composition of human dental plaque. METHODS: A total of 24 healthy adult volunteers were selected and randomly distributed into three experimental groups. After a supragingival scaling, the subjects were treated with an application of IgY containing spray (test group, n = 9), a 0.15% chlorhexidine(CH) spray(positive control group, n = 9) or a placebo phosphate buffered saline(PBS) spray without any active ingredients(negative control group, n = 6) three times daily for three weeks. Pooled plaque samples from the smooth surfaces of teeth were collected for microbiologic analysis before administration (baseline, day 0), during treatment(days 7, 14 and 21) and after withdrawal of the agents(days 28, 42 and 56) and plaque index were recorded. Microbial cultivation were performed by serially diluting the samples with PBS solution an cultivating the aliquots on mitis salivarius agar(MS) and MS supplemented with bacitracin (MSB) for oral streptococci and mutans streptococci respectively. The number of colony-forming unit (CFU) per plate was counted and the percentage of mutans streptococci per oral streptococci in dental plaque were determined. The effect of IgY on colonization of mutans streptococci were analyzed by an analysis of variance (ANOVA). RESULTS: The plaque indexes remained unchanged, but mutans streptococci in dental plaque was suppressed significantly following a short term(three weeks) application of IgY, and low level of mutans streptococci persisted for at least 5 weeks after withdrawal of IgY. CONCLUSION: The results suggest that the immunization with specific immunoglobulin yolk against mutans streptococci could be useful for long term suppression of mutans streptococci colonization in human dental plaque.

Adult↗
PubMed2003

[CpG oligodeoxynucleotide enhances humoral and cellular immune responses against HBsAg in mice].

OBJECTIVE: To induce stronger humoral and cell mediated immune response against HBsAg and seek more effective methods to treat hepatitis B virus infection. METHODS: 21-mer phosphorothioate oligodeoxynucleotide (ODN) and its control ODN were synthesized and used as an adjuvant of HBsAg and commercial hepatitis B vaccine to enhance their immune responses against HBsAg. Four groups of 33 mice received 2 doses of the mixtures (1.67 microg HBsAg: 16.5 microg CpG ODN) at an interval of 15 days. Group A: HBsAg only, 7 mice; group B: HBsAg + CpG ODN, 10 mice; group C: commercial hepatitis B vaccine, 6 mice; group D: commercial hepatitis B vaccine + CpG ODN, 10 mice. Serum anti-HBs levels and cytotoxic T lymphocyte response (CTL) of splenocytes were assayed 15 days after the last vaccination. RESULTS: The mean absorbent values of blood anti-HBs in the 4 groups were 0.109, 0.435, 0.422 and 0.575, respectively. The rates of CTL response were 8.5%, 37.0%, 1.5%, and 28.0%, respectively. CONCLUSIONS: (1) CpG ODN markedly improves humoral (anti-HBs) and cellular immune response (CTL) induced by HBsAg immunization. (2) There is a synergistic interaction between aluminum and CpG ODN in enhancing the humoral and cellular immune responses against HBsAg. Therefore, CpG ODN might be used to treat chronic hepatitis B virus infection after its safety and effectiveness have been confirmed.

Adjuvants, Immunologic↗
PubMed2003

[Effect of temperature on the translocation of exogenous 32P in water column, Microcystis aeruginosa and sediments].

Effect of temperature on the translocation of exogenous phosphorus in the simulative ecosystem composing of water, Microcystis aeruginosa and sediments was studied with the method of phosphorus isotope tracer. Exogenous 32P was initially distributed rapidly in the ecosystems in a mode of physical chemistry, irrespective of the influence of different temperature. Then, the translocation of 32P was significantly affected by the growth of M. aeruginosa in the ecosystem. Relatively high temperature was favorable to the growth of M. aeruginosa and accelerated the adsorption of exogenous phosphorus. The maximum concentration of exogenous endocellular phosphorus in M. aeruginosa was only related with the initial phosphorus concentration of water environment. The growth curve of M. aeruginosa contained short lag phase, 7-day log phase and decline phase but no obvious stationary phase at 25 degrees C. After certain amounts of exogenous phosphorus were accumulated in M. aeruginosa, its growth was independent of the amounts of endocellular phosphorus at 25 degrees C. The exogenous 32P moved from water and M. aeruginosa to sediment continuously and almost all of them transferred into sediment through the sedimentation of M. aeruginosa at the end of the experiment. The concentration of dissoluble exogenous 32P declined rapidly when water temperature was high and was less than 0.00716 mg.L-1 after 7 days.

Ecosystem↗
PubMed2002

The sedimentation capabilities of hexadecyltrimethylammonium-modified montmorillonites.

Natural montmorillonite was modified with a quaternary ammonium compound, hexadecyltrimethylammonium (HDTMA). The sedimentation capabilities of unmodified and modified montmorillonites were then investigated. The sedimentation velocity of modified montmorillonites increased if the amounts of adsorbed HDTMA were from 0.3 to 1.0 times the cation exchange capacitity (CEC). It also emerged that the sedimentation capability of modified montmorillonites was improved and that the variously CEC-modified montmorillonites had similar sedimentation capabilities after they had sorbed organic matter from oily wastewater. Thus, modified montmorillonites (especially 0.5 CEC treatment) had good sedimentation capabilities for sorbing organic substance and can act as carriers in wastewater biotreatment.

Adsorption↗