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Biomedical subjects

Y Zhou

Publications and source records attributed to Y Zhou.

At least 181 records · Page 10Linked to original sources
PubMed2001

U(L)31 and U(L)34 proteins of herpes simplex virus type 1 form a complex that accumulates at the nuclear rim and is required for envelopment of nucleocapsids.

The herpes simplex virus type 1 (HSV-1) U(L)34 protein is likely a type II membrane protein that localizes within the nuclear membrane and is required for efficient envelopment of progeny virions at the nuclear envelope, whereas the U(L)31 gene product of HSV-1 is a nuclear matrix-associated phosphoprotein previously shown to interact with U(L)34 protein in HSV-1-infected cell lysates. For these studies, polyclonal antisera directed against purified fusion proteins containing U(L)31 protein fused to glutathione-S-transferase (U(L)31-GST) and U(L)34 protein fused to GST (U(L)34-GST) were demonstrated to specifically recognize the U(L)31 and U(L)34 proteins of approximately 34,000 and 30,000 Da, respectively. The U(L)31 and U(L)34 gene products colocalized in a smooth pattern throughout the nuclear rim of infected cells by 10 h postinfection. U(L)34 protein also accumulated in pleiomorphic cytoplasmic structures at early times and associated with an altered nuclear envelope late in infection. Localization of U(L)31 protein at the nuclear rim required the presence of U(L)34 protein, inasmuch as cells infected with a U(L)34 null mutant virus contained U(L)31 protein primarily in central intranuclear domains separate from the nuclear rim, and to a lesser extent in the cytoplasm. Conversely, localization of U(L)34 protein exclusively at the nuclear rim required the presence of the U(L)31 gene product, inasmuch as U(L)34 protein was detectable at the nuclear rim, in replication compartments, and in the cytoplasm of cells infected with a U(L)31 null virus. When transiently expressed in the absence of other viral factors, U(L)31 protein localized diffusely in the nucleoplasm, whereas U(L)34 protein localized primarily in the cytoplasm and at the nuclear rim. In contrast, coexpression of the U(L)31 and U(L)34 proteins was sufficient to target both proteins exclusively to the nuclear rim. The proteins were also shown to directly interact in vitro in the absence of other viral proteins. In cells infected with a virus lacking the U(S)3-encoded protein kinase, previously shown to phosphorylate the U(L)34 gene product, U(L)31 and U(L)34 proteins colocalized in small punctate areas that accumulated on the nuclear rim. Thus, U(S)3 kinase is required for even distribution of U(L)31 and U(L)34 proteins throughout the nuclear rim. Taken together with the similar phenotypes of the U(L)31 and U(L)34 deletion mutants, these data strongly suggest that the U(L)31 and U(L)34 proteins form a complex that accumulates at the nuclear membrane and plays an important role in nucleocapsid envelopment at the inner nuclear membrane.

Animals↗
PubMed2001

Characterization of DNA binding protein of porcine adenovirus type 3.

To identify and characterize the protein encoded by the E2A region of porcine adenovirus (PAV)-3, DNA sequence coding for a portion (amino acids 102-457) of the DNA binding protein (DBP) open reaching frame was cloned and expressed in Escherichia coli as a fusion protein with glutathione S-transferase protein of Schistosoma japonica. The affinity-purified fusion protein was used to immunize rabbits. Immunoprecipitation/Western blot analysis demonstrated that the antisera specifically recognized a protein of 50 kD in PAV-3-infected cells. Immunoperoxidase staining detected the DBP protein predominantly in the nucleus of the cells. Western blot analysis demonstrated that DBP was detected as early as 6 h after infection and remained detectable throughout the infection. Based on these results, a novel assay for quantitation of PAV-3 was established. The assay is less time consuming and can be performed in different porcine cells. In addition, virus titers determined by this assay are comparable to the standard plaque assay.

Adenovirus E2 Proteins↗
PubMed2001

Interferon alpha induction of Stat1 and Stat2 and their prognostic significance in carcinoid tumors.

IFN-alpha has been shown to elicit antitumor activity in carcinoid tumors. In the present study the effects of IFN-alpha on the protein expression involved in the IFN-alpha signaling, which were recognized as signal transducer and activators of transcription (Stats), were investigated. Archive specimens from 45 carcinoid patients, 33 before IFN-alpha and 45 during treatment, were studied. The tissues were immunostained for protein expression by using monoclonal anti-Stat1 and anti-Stat2 antibodies. Results showed that Stat1 and Stat2 immunostaining were significantly increased during IFN-alpha treatment. Stats scores were significantly increased only in patients with objective response as well as those with stable disease but not in those with progressive disease. The induction of Stats correlated with the survival rates of the patients. In addition, both Stat scores significantly correlated with the p68 protein expression. In a carcinoid tumor cell line, Bon1, IFN-alpha dose-dependently increased the Stat expression. Analysis of cell fractions showed that IFN-alpha increased Stat protein both in cytoplasm and nucleoplasm of the cells. Furthermore, IFN-alpha enhanced tyrosine phosphorylation of Stat1 and Stat2. Thus, the antitumor effect, in vivo and in vitro, in IFN-alpha-treated carcinoid tumors seems to be mediated via upregulation of Stat proteins and enhancement of phosphorylation of these proteins.

Antineoplastic Agents↗
PubMed2001

Characterization of a calcium-activated chloride channel as a shared target of Th2 cytokine pathways and its potential involvement in asthma.

Interleukin (IL)-9 is a T helper (Th) 2 cytokine recently implicated as an essential factor in determining susceptibility to asthma. Transgenic mice overexpressing IL-9 exhibit many features that are characteristic of human asthma. To better understand the mechanism by which IL-9 mediates the various biologic activities in asthma, we performed suppressive subtraction hybridization with whole lung from IL-9 transgenic and control mice. Here we report the identification of mCLCA3, a calcium-activated chloride channel that was specifically induced in the lung epithelium of IL-9 transgenic mice. Expression of mCLCA3 could also be induced by intratracheal administration of IL-9 or other Th2 cytokines (IL-4, IL-13), but not by interferon-gamma. Moreover, expression of mCLCA3 was induced in the lung of antigen-exposed mice, and this induction could be suppressed by neutralizing IL-9 antibody treatment, indicating IL-9 is both necessary and sufficient to induce mCLCA3 in this experimental model of asthma. Finally, we demonstrate that hCLCA1 is the human counterpart to mCLCA3 and is also induced in vitro in human primary lung cells by Th2 cytokine treatment. Together, these data strongly implicate the involvement of mCLCA3 (in mice) and hCLCA1 (in humans) in the pathogenesis of Th2 cytokine-mediated asthmatic disorders.

Amino Acid Sequence↗
PubMed2001

UGRP1, a uteroglobin/Clara cell secretory protein-related protein, is a novel lung-enriched downstream target gene for the T/EBP/NKX2.1 homeodomain transcription factor.

A novel gene that is down-regulated in lungs of T/ebp/Nkx2.1-null mouse embryos has been identified using a suppressive-subtractive hybridization method. The gene product is a secreted protein, forms a homodimer, and exhibits an amino acid sequence similar to that seen in the uteroglobin/Clara cell secretory protein family of proteins. This gene, designated Ugrp1 (uteroglobin-related protein 1), consists of three exons and two introns and produces three transcripts by alternative splicing. The Ugrp1 gene was localized by fluorescence in situ hybridization to mouse chromosome 18 at region 18C-D; this region is homologous with human 5q31-34, where one of the asthma susceptibility genes has been assigned. UGRP1 mRNA is predominantly expressed in the lung, with low levels of expression in the thyroid. Expression in the lung is detectable as early as embryonic day 12.5 and increases markedly by embryonic day 16.5. In T/ebp/Nkx2.1-null embryo lungs, UGRP1 expression was significantly reduced as assessed by RT-PCR analysis. Cotransfection assays using a T/EBP/NKX2.1 expression construct with Ugrp1 promoter-luciferase reporter constructs confirmed that T/EBP/NKX2.1 regulates Ugrp1 gene activity at the transcriptional level. Thus, Ugrp1 is a downstream target gene for the T/EBP/NKX2.1 homeodomain transcription factor. Changes in UGRP1 mRNA levels in lungs from antigen-sensitized mice suggest the possible involvement of UGRP1 in inflammation.

Alternative Splicing↗
PubMed2001

Clinical trial of arotinolol in the treatment of hypertension: dippers vs. non-dippers.

To compare the effects of an alpha, beta blocker, arotinolol, in the treatment of essential hypertension between patients with a dipper and those with a non-dipper profile by means of 24-h ambulatory blood pressure monitoring (ABPM), a multicenter single blind parallel trial was carried out in five clinical centers. After a one-week single blind placebo run-in period, the patients underwent ABPM if their clinic diastolic blood pressure (DBP) ranged from 90-109 mmHg and their clinic systolic blood pressure (SBP) was <180 mmHg. They were divided into two groups according to the absence (non-dipper group, 24 cases) or presence (dipper group, 23 cases) of nocturnal BP reduction > or =10% of daytime BP. ABPM was measured again at the end of the active treatment phase. All patients were given Arotinolol 10-20 mg twice daily for 4 weeks. Twenty four-hour systolic and diastolic average BPs (MSBP, MDBP), 24-h systolic and diastolic blood pressure load (LS BP, LDBP), daytime systolic and diastolic average BPs (dMSBP, dMDBP), daytime systolic and diastolic blood pressure load (dLSBP, dLDBP), nighttime systolic and diastolic average BPs (nMSBP, nMDBP) and nighttime systolic and diastolic blood pressure load (nLSBP, nLDBP) were calculated. Arotinolol was effective in 78.2% of dippers and 54.2% of non-dippers, but the difference in effectiveness between these groups was not statistically significant. After treatment, SBP and DBP-including 24-h, daytime and nighttime systolic and diastolic BPs- were significantly reduced in both groups. During the daytime period, the systolic and diastolic blood pressures were significantly reduced in both dippers and non-dippers, while nighttime systolic and diastolic blood pressures were significantly reduced only in the non-dipper group. No significant changes were found in the dipper group over this period. In conclusion, Arotinolol, which can be dosed twice daily, is an effective antihypertensive agent which effectively lowers blood pressure during the day while reducing nighttime blood pressure more in non-dippers than in dippers, without excessive lowering blood pressure in the latter.

Adrenergic beta-Antagonists↗
PubMed2001

Amyloid fibril formation in microwell plates for screening of inhibitors.

Fibril formation is the basis of amyloid production in a number of disease states, such as Alzheimer's disease, diabetes and immunocytic dyscrasias. Compounds that inhibit fibril formation could be directly relevant to the treatment of amyloid diseases, and may also provide a foundation for the development of interventions in other molecular condensation diseases ranging from sickle cell anemia to atherosclerosis. We developed an economical and convenient high-throughput method for screening compounds against fibril formation in microwell plates. Chalcones, flavonoids and biflavonoids were screened against fibril formation by a recombinant antibody variable domain (V1). Chalcones 6 and 14 were found to demonstrate inhibition at 0.1 microM in 79 microM of protein solution in both test tube and microwell plate assays. The concentration of protein in the microwell plate assay could be as low as 5 microM using ThT as a monitoring agent. Molecular modeling studies indicated that both compounds could be individually docked into a binding site at the monomer-monomer interface of the V(L) protein dimer. These studies suggested that these compounds could potentially stabilize the VL dimer and therefore reduce its tendency to form fibrils. These findings may provide the basis for a new therapeutic approach to prevent or treat amyloid diseases.

Amyloid beta-Peptides↗
PubMed2001

[Effect of methionine supplementation on the selenium bioavailability in rats fed on grains from Keshan disease endemic area].

In order to study the effect of dietary methionine on tissue selenium and glutathione peroxidase activity(GPX) in rats fed on grains from Keshan Disease endemic area, a nonpurified selenium (Se) deficient diet (containing Se 0.007 mg/kg diet) taken from Keshan Disease endemic area was supplemented with selenomethionine (SeMet) to provide selenium content in diet for 0.007, 0.06 and 0.50 mg/kg and added or not added with DL-methionine (Met) 4 g/kg to make 6 kinds of diet. Fifty four male weanling Wistar rats were randomly divided into 6 groups, consuming each one of the 6 diets for 8 weeks. The Se content and GPX activity in tissues of animals with Met supplementation were compared with those without Met supplementation. The results showed that adding Met did not result in significant changes of tissue Se content and GPX activity in animals having dietary Se of 0.007 mg/kg, except for lower muscle Se content. However, in animals having dietary Se of 0.06 mg/kg and supplementing Met resulted in selenium redistribution in tissues-decrease of Se content in muscle, increase of Se content in liver and blood and significant elevation of GPX activity in all tissues. In animals having methionine-added and dietary Se of 0.50 mg/kg, tissue Se content declined to various extent, while GPX activity remained unchanged. The results suggest that SeMet (main chemical form of Se in cereals) is preferentially incorporated into body protein when dietary methionine is limited. Once Met is supplemented, dietary SeMet would provide more Se for the syntheses of GPX and other selenoproteins. The results further suggest that marginal deficiency in sulfur-containing amino acids in the diet from Keshan Disease endemic area might be an additional factor for the development of Keshan Disease under selenium deficiency.

Animals↗
PubMed2001

Expression, purification and biochemical characterization of a recombinant phospholipase A2, with anticoagulant activity from Agkistrodon halys Pallas.

A cloned cDNA encoding a PLA2 from Agkistrodon halys Pallas was found to have conservative residues Glu53 and Trp70 but with Lys56 and Lys67 substituted by Thr56 and Asp67, respectively, when compared with sequences of other class II PLA2 with anticoagulant activity. It was inserted into a temperature-sensitive bacterial expression vector and effectively expressed in Escherichia coli RR1. The protein was produced as insoluble inclusion bodies and recovered by centrifugation after enzyme digestion. By washing to partial purification, the expression product was refolded and was purified by FPLC superose 12 to appear as a single band in SDS-PAGE. The recombinant protein proved to have obvious enzymatic, anticoagulant and hemolytic activities, which were removed after modification by p-BPB. These findings suggest that the pharmacological activities of this recombinant PLA2 may be related to its catalytic activity and warrant further research on the structure-function relationships of the pharmacological site of the PLA2 from Agkistrodon halys Pallas.

Animals↗
PubMed2001

Identification of key residues responsible for enzymatic and platelet-aggregation-inhibiting activities of acidic phospholipase A2S from Agkistrodon halys Pallas.

Site-directed mutagenesis was used to probe the structural and functional relationship of acidic phospholipase A2 from Agkistrodon halys Pallas. The mutants are AP-E6R (E6R), AP-D115K (D115K), AP-6R115K (E6R, D115K), AP-Y118M (Y118M), and AP-W119T (W119T). All mutants were inserted into a bacterial expression vector and effectively expressed in E. coli RR1. The purified recombinant enzymes were used to assay for enzymatic and inhibiting platelet aggregation activities. The enzymatic activities of AP-D115K, AP-Y118M and AP-W119T are close to that of denatured-refolded acidic phospholipase A2, while the enzymatic activities of AP-E6R, AP-6R1 15K are lower than that of denatured-refolded acidic phospholipase A2 (AP-WT). In these five mutants, AP-Y118M showed strongest inhibiting effect on platelet aggregation, which is the same as that of AP-WT, AP-W119T showed only modest activity and AP-E6R, AP-D115K, AP-6R115K showed little activity. To study the structural and functional relationships among these five mutants, molecular modeling of these five mutants was done. The roles of various amino acid residues in the enzymatic activity and pharmacological activity of acidic phospholipase A2 are discussed.

Adult↗
PubMed2001

[Molecular characterization of glucose-6-phosphate dehydrogenase deficiency in the Han and Li nationalities in Hainan, China and identification of a new mutation in human G6PD gene].

OBJECTIVE: To elucidate the molecular basis of G6PD deficiency in the Han and Li nationalities in Hainan, China. METHODS: Polymerase chain reaction and restriction enzyme digestion were used to screen the mutations 1388G-->A, 1360C-->T, 1024C-->T, 592C-->T, 517T-->C, 493A-->G, 487G-->A, 392G-->T and 95A-->G. Single strand conformation polymorphism analysis was used to screen the other mutations followed by DNA sequencing to characterize the mutations of the samples with abnormal SSCP bands. RESULTS: Of the fifty-nine Han cases with G6PD deficiency, fourteen with 1388G-->A (23.7%), three with 871G-->A(5.1%), one with 835A-->T(1.7%), one with 517T-->C (1.7%), three with 392G-->T(5.1%), and four with 95A-->G(6.8%) were found. Of the thirty-two Li cases with G6PD deficiency, six with 1388G-->A(18.8%), three with 871G-->A(9.4%), and two with 95A-->G(6.3%) were found. A new mutation 835A-->G which causes the substitution of Ala for Thr at 279 in a Han case was identified and named as G6PD Haikou. The enzyme activity of the variant is about 10% of the normal and lower than the activity of the variant 835A-->T with about 40% of the normal. Analysis of the 3D model of human G6PD has revealed that the hydroxyl group of Thr at 279 is a group in maintaining the interaction of the G6PD subunits. CONCLUSION: The most common mutations of G6PD deficiency in Han and Li nationalities in Hainan are similar. Compared with the mutation spectrum of G6PD gene in the populations in other regions of China, the results indicate that some G6PD gene mutations are widespread in the populations of different regions in the southern part of China. The hydroxyl group of the Thr at 279 of human G6PD may be a necessary group for maintaining the interaction of the G6PD subunits and the enzyme activity.

Child↗
PubMed2001

[Biomechanical studies on two thoracolumbar implants in cadaveric spine].

The aim of these studies was to evaluate the biomechanical characteristics of two devices and provide information for clinical choice. In vitro cadaveric spine testing which consisted of the stability test and the yield strength test was performed. In hemicorpectomy model, the AF was stiffer than the Kaneda in flexion, extension and left lateral bending (P < 0.01). In total corpectomy model, the AF was stiffer than the Kaneda in flexion, left lateral bending and axial rotation (P < 0.01). The average values of yield strength(M) for the Kaneda, the AF and the intact were 477.3 kg, 544.4 kg and 493.6 kg resectively. The stability of the AF is superior to that of the Kaneda. In total corpectomy, the Kaneda is significantly unstable in axial rotation. Both devices restore effectively load carrying capacity of the spine.

Adult↗
PubMed2001

[Significance of detection of transfusion transmitted virus in extrahepatic tissues].

OBJECTIVE: To investigate the location and distribution of transfusion transmitted virus (TTV) in the liver and extrahepatic tissues. METHODS: TTV DNA was detected in paraffin-embedded autopsy liver and extrahepatic tissues, including liver, pancreas, kidney, spleen, testicle, and heart from 13 patients with non A-G hepatitis by nested-PCR and in situ hybridization (ISH) techniques. RESULTS: Positive hybridization signals of TTV nucleus acid were observed in 5 liver, 3 kidney, 2 pancreas and spleen tissues, respectively. TTV DNA was detected in one from each two samples of testicle and heart. Positive signal was mainly located in nucleoli of the liver and extrahepatic parenchymal cells. There was not obvious pathological damage in those extrahepatic tissues. The positive rate of PCR approximately corresponded to ISH. CONCLUSIONS: TTV can infect hepatic and extrahepatic tissues and its infection in extrahepatic tissues might be responsible for a state of reinfection and higher prevalence in different population.

Adult↗
PubMed2001

[Decomposition of aqueous sodium pentachlorophenolate (PCP-Na) by using TiO2 coating photocatalyst].

Titanium dioxide (TiO2) photocatalysts were coated on hollow glass beads by sodium silicate (Na2SiO3.9H2O) solution. The coated catalysts were characterized by BET, XRD. Their photoactivity were examined using photocatalytic degradation of sodium pentachlorophenolate(PCP-Na) and glucose solution. The impact of catalysts dosage, PCP-Na initial concentration, initial pH and oxygen concentration on reaction kinetics were also studied in detail. The experiments illustrated that the performance of C3-type catalysts was satisfactory. Conditions of the experiments were following: The initial concentration of PCP-Na and CODCr were 10 mg.L-1 and 400 mg.L-1, respectively, and illumination time was 2 hours and catalysts dosage was 2 g.L-1, the removal rates of CODCr and PCP-Na were above 65% and 92% respectively. Optimum dosage of C3-type catalysts was 2-2.5 g.L-1, DO was no less than 3 mg.L-1.

Catalysis↗
PubMed2001

Formation of retinal pigment epithelium in vitro by transdifferentiation of neural retina cells.

Chick embryonic neural retina (NR) dedifferentiates in culture and can transdifferentiate spontaneously into retinal pigment epithelium (RPE). Both, primary RPE and transdifferentiated RPE (RPEt), are characterized by pigmentation, expression of RPE-specific protein, eRPEAG and lack of expression of the neural cell adhesion molecule, NCAM. In contrast, NR cells are unpigmented and express NCAM but not eRPE(AG). Functionally, both primary RPE and the RPEt cells display a pH(i) response to bFGF, which is different from that of the NR. We used these characteristics to distinguish cell types in primary cultures of chick NR and follow the changes in phenotype that occur during transdifferentiation. We show that the RPEt forms as small "islands" in the packed regions of the primary, "mother" NR cell sheets, in a stochastic process. Because of a small number of cells involved in the initiation of the transdifferentiation we refer to it as a "leader effect" to contrast it with the "community effect" which requires many competent cells to be present in a group to be able to respond to an inductive signal. The RPEt then expands centrifugally and underneath the surrounding NR sheet. To determine if the RPEt maintains its identity in isolation while displaying the RPE-typical phenotypic plasticity, we explanted the islands of RPEt and treated half of them with bFGF. The untreated RPEt maintained its closely packed, polygonal pigmented phenotype but the bFGF-treated RPEt transdifferentiated into a non-pigmented, NR-like phenotype, indicating that RPEt encompasses the full differentiation repertoire of native RPE.

Animals↗
PubMed2001

[Serum markers and pathological evaluation in hepatitis fibrosis of chronic hepatitis B treated with interferon alpha].

OBJECTIVE: To evaluate the anti-fibrotic effect of interferon alpha and to study the relationship between the anti-fibrotic effect and the efficacy of anti-virus in patients with chronic hepatitis B treated with interferon alpha. METHODS: Thirty-six patients with chronic hepatitis B were treated with interferon alpha. Before, during and after the treatment, the levels of hyaluronic acid (HA), type III procollagen (PC-III), type IV collagen(IV-C), laminin (LN) and transforming growth factor beta 1 (TGF-beta 1) were measured as the markers of hepatic fibrosis. Needle biopsy sections of the liver taken before and at the end of IFN treatment were assessed and compared according to the modified histological activity index (HAI) and hepatic fibrosis (HF) scoring system. RESULTS: In IFN group, the levels of HA, PC-III, IV-C, LN, and TGF-beta 1 after treatment were all significantly lower than those before treatment (P<0.01). The levels of HA, PC-III, and TGF-beta 1 after treatment were significantly lower in IFN group than in control one. HAI scores decreased from 9.3+/-3.2 to 6.2 +/-2.1 and HF scores decreased from 7.5+/-2.2 to 5.1+/-1.8 after treatment. CONCLUSIONS: The improvement of hepatic fibrosis closely related to the efficacy of anti-virus. Interferon alpha therapy is effective for hepatic fibrosis of chronic hepatitis B.

Adolescent↗
PubMed2001

[Growth and metabolism of human skin fibroblasts cultured on microcarriers].

Human foreskin fibroblasts were cultured in vitro on microcarriers in spinners and traditional static flasks. The cultured cells obtained with these approaches were compared in cell shape, cell growth, cell production, and the metabolisms of glucose, lactate, and ammonium. The cells from microcarrier cultures through medium exchange were 8 times more than those from traditional static flasks. It was found that the specific growth rate and specific glucose consumption rate in microcarrier spinner cultures were 0.64/d-1 and 5.56 mmol/10(9) cell/d, respectively, higher than those in static flask cultures. However, the average lactate yield on glucose consumption in spinner cultures was only 0.955 mmol/mmol, lower than that in static flask cultures, 1. 125 mmol/mmol. This indicated that the energy metabolism in spinner cultures was significantly more efficient than that in static flasks. The experimental results from this work suggest that the microcarrier culture system is a suitable way to expand the seeding cells for tissue engineering, due to its ideal cultivation environment provided.

Cell Division↗