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Biomedical subjects

Li Zhang

Publications and source records attributed to Li Zhang.

At least 145 records · Page 8Linked to original sources
PubMed2006

Lamivudine prophylaxis reduces the incidence and severity of hepatitis in hepatitis B virus carriers who receive chemotherapy for lymphoma.

BACKGROUND: Hepatitis B virus (HBV) infection is a common disease in China. Severe hepatitis is a well recognized complication in HBV carriers with malignant disease who receive cytotoxic chemotherapy. The objective of the current study was to assess the value of antiviral lamivudine for reducing the incidence and severity of hepatitis in HBV carriers with lymphoma who receive chemotherapy. METHODS: Two groups were compared in this nonrandomized study. The prophylactic lamivudine group was comprised of 40 patients who received oral lamivudine at a dose of 100 mg daily before and until at least 8 weeks after they discontinued chemotherapy. The historic control group was comprised of 116 patients who received chemotherapy without lamivudine. The incidence and severity of hepatitis and other adverse clinical outcomes were compared between the two groups. Significant prognostic factors for the development of hepatitis were determined based on data derived from the control group. RESULTS: The two groups were comparable in most clinical baseline characteristics, including gender distribution, age, tumor types, primary treatment, hepatitis Be antigen status, and the use of anthracyclines or/and prednisone. In the prophylactic lamivudine group, there was significantly less incidence of hepatitis (17.5% vs. 51.7% in the control group; P = 0.000); less severe hepatitis (according to World Health Organization [WHO] criteria) (10% with Grade 1, 5% with Grade 2, and 2.5% with Grade 3 hepatitis vs. 3.4% with Grade 1, 12.1% with Grade 2, 12.9% with Grade 3, and 23.3% with Grade 4 hepatitis in the control group; P = 0.000); and less disruption of chemotherapy (10.0% vs. 37.1% in the control group; P = 0.001). The overall mortality as a result of hepatitis in the prophylactic lamivudine group was lower compared with that in the control group, but the difference was not statistically significant (0.0% vs. 5.2%; P = 0.163). In the control group, the factor associated with a greater risk of developing hepatitis was the use of prednisone. In the prophylactic lamivudine group, 1 of 40 patients (2.5%) developed hepatitis that was attributable to HBV reactivation. Further examination demonstrated that this single patient had a variation of HBV with YMDD mutations after the use of lamivudine for 9.2 months. CONCLUSIONS: The results of the current study confirmed previous reports that lamivudine prophylaxis significantly reduced the incidence and severity of hepatitis in HBV carriers who were receiving chemotherapy for lymphoma. The chemotherapy disruption rate as a result of severe hepatitis also was decreased significantly.

Administration, Oral↗
PubMed2006

Genome-wide identification of direct targets of the Drosophila retinal determination protein Eyeless.

The discovery of direct downstream targets of transcription factors (TFs) is necessary for understanding the genetic mechanisms underlying complex, highly regulated processes such as development. In this report, we have used a combinatorial strategy to conduct a genome-wide search for novel direct targets of Eyeless (Ey), a key transcription factor controlling early eye development in Drosophila. To overcome the lack of high-quality consensus binding site sequences, phylogenetic shadowing of known Ey binding sites in sine oculis (so) was used to construct a position weight matrix (PWM) of the Ey protein. This PWM was then used for in silico prediction of potential binding sites in the Drosophila melanogaster genome. To reduce the false positive rate, conservation of these potential binding sites was assessed by comparing the genomic sequences from seven Drosophila species. In parallel, microarray analysis of wild-type versus ectopic ey-expressing tissue, followed by microarray-based epistasis experiments in an atonal (ato) mutant background, identified 188 genes induced by ey. Intersection of in silico predicted conserved Ey binding sites with the candidate gene list produced through expression profiling yields a list of 20 putative ey-induced, eye-enriched, ato-independent, direct targets of Ey. The accuracy of this list of genes was confirmed using both in vitro and in vivo methods. Initial analysis reveals three genes, eyes absent, shifted, and Optix, as novel direct targets of Ey. These results suggest that the integrated strategy of computational biology, genomics, and genetics is a powerful approach to identify direct downstream targets for any transcription factor genome-wide.

Animals↗
PubMed2006

Ischemic cerebral tissue response to subventricular zone cell transplantation measured by iterative self-organizing data analysis technique algorithm.

To investigate the changes of the ischemic lesion in rat brain after subventricular zone (SVZ) cell transplantation and the influence of the grafted cells on the appearance of angiogenesis, SVZ cells, superparamagnetically labeled, were intracisternally transplanted into the rat brain 48 h after onset of embolic stroke. A complete set of magnetic resonance (MR) images was acquired for all animals with (n=8) and without (n=3) cell grafting at approximately 24 h, 72 h, and weekly for 6 weeks after stroke. Transplanted cells were tracked by high-resolution three-dimensional gradient-echo images and the interaction between the cells and ischemic lesion was detected by ISODATA (Iterative Self-Organizing Data Analysis Technique Algorithm) calculated from T(1), T(2) and T(1sat) maps. Tissue status from ISODATA was characterized by a specific signature, which represents the deviation from normal tissue in the feature space. Transplanted SVZ cells selectively migrated towards the ischemic side of the rat brain and approached the lesion boundary within 1-week after grafting. Cell treated rats exhibited a significant reduction of average lesion size compared with control rats (P<0.05). A significant reduction of tissue signature (P<0.001) induced by cell transplantation was localized to the position of grafted cells, and these sites exhibited stably restored cerebral blood flow (CBF) (approximately 85% of normal CBF). Angiogenesis was present in sites either immediately adjacent to or surrounded by the grafted cells. Our data indicate that map-ISODATA accurately and dynamically characterizes the ischemic lesion and its response to cell therapy.

Algorithms↗
PubMed2006

Can electronic search engines optimize screening of search results in systematic reviews: an empirical study.

BACKGROUND: Most electronic search efforts directed at identifying primary studies for inclusion in systematic reviews rely on the optimal Boolean search features of search interfaces such as DIALOG and Ovid. Our objective is to test the ability of an Ultraseek search engine to rank MEDLINE records of the included studies of Cochrane reviews within the top half of all the records retrieved by the Boolean MEDLINE search used by the reviewers. METHODS: Collections were created using the MEDLINE bibliographic records of included and excluded studies listed in the review and all records retrieved by the MEDLINE search. Records were converted to individual HTML files. Collections of records were indexed and searched through a statistical search engine, Ultraseek, using review-specific search terms. Our data sources, systematic reviews published in the Cochrane library, were included if they reported using at least one phase of the Cochrane Highly Sensitive Search Strategy (HSSS), provided citations for both included and excluded studies and conducted a meta-analysis using a binary outcome measure. Reviews were selected if they yielded between 1000-6000 records when the MEDLINE search strategy was replicated. RESULTS: Nine Cochrane reviews were included. Included studies within the Cochrane reviews were found within the first 500 retrieved studies more often than would be expected by chance. Across all reviews, recall of included studies into the top 500 was 0.70. There was no statistically significant difference in ranking when comparing included studies with just the subset of excluded studies listed as excluded in the published review. CONCLUSION: The relevance ranking provided by the search engine was better than expected by chance and shows promise for the preliminary evaluation of large results from Boolean searches. A statistical search engine does not appear to be able to make fine discriminations concerning the relevance of bibliographic records that have been pre-screened by systematic reviewers.

Abstracting and Indexing↗
PubMed2006

Quantitative evaluation of thin-layer chromatography with image background estimation based on charge-coupled device imaging.

The main limitation of image processing based on charge-coupled device (CCD) imaging in quantitative evaluation of thin-layer chromatography (TLC) is its nonuniform illumination. This paper presents a novel method to solve the problem. First, the background is estimated by employing the cubic spline surface construction. Then the estimated background is subtracted from the original image to make the image segmentation; Finally, the gray level integration for each object is calculated, which is proportional to the value of samples. Experiment shows that the linear correlation coefficient between gray integration and concentration of samples is 0.9978.

Chromatography, Thin Layer↗
PubMed2006

[Perinatal outcomes of intrahepatic cholestasis of pregnancy: analysis of 1210 cases].

OBJECTIVE: To study the perinatal outcomes of intrahepatic cholestasis of pregnancy (ICP). METHODS: The clinical data of 1210 cases of ICP in recent ten years were retrospectively analyzed. RESULTS: The incidence rates of perinatal outcomes of ICP were as follows: 19.0% (230/1210) for threatened premature labor, 24.0% (290/1210) for premature delivery; 23.2% (281/1210) for meconium stained amniotic fluid, 7.1% (86/1210) for neonatal asphyxia, 22.5 per thousand (27/1210) for perinatal mortality, 85.9% (1039/1210) for cesarean section, 0.9% (11/1210) for fetal growth restriction (FGR), 1.4% (17/1210) for postpartum hemorrhage, and 8.1% (101/1210) for preeclampsia. Threatened premature labor occurred beyond the gestation gestation period of 32 weeks in 88.7% (204/230) of the patients, and the fetal death rate in threatened premature labor was 46.7% (7/15). Premature delivery occurred after 34 weeks of gestation in 96.2% of the patients (279/290) 89.7% (260/290) of which were caused by cesarean section because of abnormal fetal monitoring. 41.3% of the cases with meconium stained amniotic fluid (116/281) occurred before the onset of labor. Fetal death accounted for 56% (15/27) of perinatal death, 80% (12/15) of which happened after the gestation week of 35 (36.5 +/- 1.2) with normal fetal heart rate monitoring. 95% (19/20) of the fetal death and stillbirth occurred after threatened premature labor and occasional uterine contractions, or at the early stage of labor. CONCLUSION: The rates of FGR, postpartum hemorrhage, and preeclampsia in ICP are almost the same as those of the normal pregnancy. Routine fetal heart rate monitoring methods cannot predict fetal death. The important measures to decrease the perinatal mortality include paying attention to fetal monitoring when threatened premature labor, occasional uterine contractions and prenatal meconium occur, and at the early stage of labor, and management of threatened premature labor and timely intervention of pregnancy (at the gestation period of 34 - 37 weeks).

Cholestasis, Intrahepatic↗
PubMed2006

Monoclinic structured BiVO4 nanosheets: hydrothermal preparation, formation mechanism, and coloristic and photocatalytic properties.

Bismuth vanadate (BiVO(4)) nanosheets have been hydrothermally synthesized in the presence of sodium dodecyl benzene sulfonate (SDBS) as a morphology-directing template. The nanosheets were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) equipped with an X-ray energy dispersive spectrometer (EDS), X-ray photoelectron spectroscopy (XPS), IR spectroscopy, transmission electron microscopy (TEM), and high-resolution TEM (HR-TEM). The BiVO(4) nanosheets had a monoclinic structure, were ca. 10-40 nm thick, and showed a preferred (010) surface orientation. The formation mechanism and the effects of reaction temperature and time on the products were investigated. UV-visible diffuse reflection spectra indicated that the BiVO(4) nanosheets had outstanding spectral selectivity and improved color properties compared with the corresponding bulk materials. Furthermore, the nanosheets showed good visible photocatalytic activities as determined by degradation of N,N,N',N'-tetraethylated rhodamine (RB) under solar irradiation.

Journal Article↗
PubMed2006

Influence of an amide group in methyl octadecanoates on the monolayer stability.

The influence of a hydrogen bond donor and acceptor in the hydrophobic part of an amphiphile on the monolayer stability at the air/water interface is investigated. For that purpose, the amide group is integrated into the alkyl chain. Eight methyl octadecanoates have been synthesized with the amide group in two orientations and in different positions of the alkyl chain, namely, CH3O2C(CH2)m NHCO(CH2)n CH3 (n + m = 14): 1 (m = 1), 3 (m = 2), 5 (m = 3), 7 (m = 14); and CH3O2C(CH2)m CONH(CH2)n CH3: 2 (m = 1), 4 (m = 2), 6 (m = 3), 8 (m = 14). The monolayers have been characterized by their pi/A isotherms, their temperature dependence and Brewster angle microscopy (BAM). Amphiphile 1 with the amide group close to the ester group (m = 1) behaves like an unsubstituted fatty acid ester, while 3, 5, and 7, with the amide group in an intermediate and terminal position, exhibit a two-phase region. The amphiphiles 2, 4, 6, and 8, with a reversed orientation of the amide group, all exhibit a two-phase region with higher plateau pressures and lower collapse pressures than those of 1, 3, 5, and 7. For 7 and 8, domains of the liquid condensed (LC) phase are visualized by BAM in the two-phase region. The liquid expanded (LE)/LC-phase transitions are all exothermic with enthalpies deltaH ranging from -31 to -12 kJ/mol. Comparison with other bipolar amphiphiles indicates that the LC phase is better stabilized by the hydroxy and dihydroxy groups than by the amide group. For model compounds of 1-4, optimized conformers in the LE and LC phases have been determined by density functional theory (DFT) calculations.

Journal Article↗
PubMed2006

Immunophysical properties and prediction of activities for vaccinia virus complement control protein and smallpox inhibitor of complement enzymes using molecular dynamics and electrostatics.

We present immunophysical modeling for VCP, SPICE, and three mutants using MD simulations and Poisson-Boltzmann-type electrostatic calculations. VCP and SPICE are homologous viral proteins that control the complement system by imitating, structurally and functionally, natural regulators of complement activation. VCP and SPICE consist of four CCP modules connected with short flexible loops. MD simulations demonstrate that the rather complex modules of VCP/SPICE and their mutants exhibit a high degree of intermodular spatial mobility, which is affected by surface mutations. Electrostatic calculations using snapshots from the MD trajectories demonstrate variable spatial distribution of the electrostatic potentials, which suggests dynamic binding properties. We use covariance analysis to identify correlated modular oscillations. We also use electrostatic similarity indices to cluster proteins with common electrostatic properties. Our results are compared with experimental data to form correlations between the overall positive electrostatic potential of VCP/SPICE with binding and activity. We show how these correlations can be used to predict binding and activity properties. This work is expected to be useful for understanding the function of native CCP-containing regulators of complement activation and receptors and for the design of antiviral therapeutics and complement inhibitors.

Amino Acid Sequence↗
PubMed2006

Identification of a new Neisseria meningitidis serogroup C clone from Anhui province, China.

BACKGROUND: Outbreaks of a new serogroup C meningococcal disease emerged during 2003-04 (five outbreaks with 43 cases) and in 2004-05 (five outbreaks with 29 cases), all in Anhui province, China. We describe the molecular epidemiology and features of the causative bacterial strains. METHODS: We used pulsed-field gel electrophoresis (PFGE) and multi-locus sequence typing (MLST) to analyse the strains. FINDINGS: Of 34 strains of Neisseria meningitidis cultured during 2003-04 from Anhui province, 31 were group C meningococci, 28 of which were associated with three of five outbreaks; one from a patient and 27 from close contacts of eight patients. Of 30 strains isolated from Anhui province during 2004-05, 17 were identified as serogroup C meningococci, ten of which were associated with four of five outbreaks. In a nationwide survey, 542 strains were isolated during 2004-05; 58 were serogroup C meningococci interspersed among 11 other provinces where no serogroup C outbreak occurred. Of the 106 serogroup C strains analysed, 89 had identical PFGE patterns, designated AH1. Of 28 strains selected for MLST analyses, 25 were sequence type 4821 (ST-4821), which did not belong to any of the previously reported sequence types that can form a new hypervirulent lineage. INTERPRETATION: ST-4821 seems to be unique and caused the serogroup C meningitis outbreaks during the two seasons from 2003 to 2005 in Anhui province. The emergence of this sequence type has epidemiological importance that should be monitored for future spread in China and the rest of the world.

Child↗
PubMed2006

TLR9 activation is defective in common variable immune deficiency.

Common variable immune deficiency (CVID) is a primary immune deficiency characterized by low levels of serum immune globulins, lack of Ab, and reduced numbers of CD27+ memory B cells. Although T, B, and dendritic cell defects have been described, for the great majority, genetic causes have not been identified. In these experiments, we investigated B cell and plasmacytoid dendritic cell activation induced via TLR9, an intracellular recognition receptor that detects DNA-containing CpG motifs from viruses and bacteria. CpG-DNA activates normal B cells by the constitutively expressed TLR9, resulting in cytokine secretion, IgG class switch, immune globulin production, and potentially, the preservation of long-lived memory B cells. We found that CpG-DNA did not up-regulate expression of CD86 on CVID B cells, even when costimulated by the BCR, or induce production of IL-6 or IL-10 as it does for normal B cells. TLR9, found intracytoplasmically and on the surface of oligodeoxynucleotide-activated normal B cells, was deficient in CVID B cells, as was TLR9 mRNA. TLR9 B cell defects were not related to proportions of CD27+ memory B cells. CpG-activated CVID plasmacytoid dendritic cells did not produce IFN-alpha in normal amounts, even though these cells contained abundant intracytoplasmic TLR9. No mutations or polymorphisms of TLR9 were found. These data show that there are broad TLR9 activation defects in CVID which would prevent CpG-DNA-initiated innate immune responses; these defects may lead to impaired responses of plasmacytoid dendritic cells and loss of B cell function.

Adolescent↗
PubMed2006

[Role of urinary basic fibroblast growth factor in differentiating hemangiomas from vascular malformation].

OBJECTIVE: To investigate a novel method to differentiate hemangioma from vascular malformation, to stage hemangiomas and to monitor the efficacy of management for hemangioma. METHODS: The urinary basic fibroblast growth factor (bFGF) concentration of 144 cases (including 69 cases of proliferating hemangiomas, 41 cases of involuting hemangiomas, 23 cases of vascular malformations and 11 negative controls) was examined using enzyme linked immunosorbent assay (ELISA). RESULTS: The differences of urinary bFGF concentration among proliferating hemangiomas, involuting hemangiomas, vascular malformations and negative control were all significant, while the differences between the latter three groups were not significant. CONCLUSIONS: Our findings suggest that examination of urinary bFGF concentration using ELISA technique is helpful in differentiating hemangioma from vascular malformation, staging hemangiomas and dynamically monitoring the efficacy of treatment for hemangiomas. Our results probably shed new light on the potential pathogenesis of hemangiomas and vascular malformation.

Arteriovenous Malformations↗
PubMed2006

Noncryogenic I/Br-Mg exchange of aromatic halides bearing sensitive functional groups using i-PrMgCl-bis[2-(N,N-dimethylamino)ethyl] ether complexes.

[reaction: see text] Iodo- and bromoaromatics bearing sensitive carboxylic ester and cyano groups underwent a selective halide-magnesium exchange with isopropylmagnesium chloride at ambient temperature in the presence of bis[2-(N,N-dimethylamino)ethyl] ether to afford the corresponding Grignard reagents. The newly formed reactive Grignard reagents were allowed to react with electrophiles such as trimethylborate to afford arylboronic acids in good to excellent yields.

Journal Article↗
PubMed2006

The G12 family of G proteins as a reporter of thromboxane A2 receptor activity.

Despite advances in the understanding of pathways regulated by the G12 family of heterotrimeric G proteins, much regarding the engagement of this family by receptors remains unclear. We explore here, using the thromboxane A2 receptor TPalpha, the ability of G12 and G13 to report differences in the potency and efficacy of receptor ligands. We were interested especially in the potential of the isoprostane 8-iso-prostaglandin F (8-iso-PGF2alpha), among other ligands examined, to activate G12 and G13 through TPalpha explicitly. We were also interested in the functionality of TPalpha-Galpha fusion proteins germane to G12 and G13. Using fusion proteins in Spodoptera frugiperda (Sf9) cells and independently expressed proteins in human embryonic kidney 293 cells, and using guanosine 5'-O-(3-[35S]thio)triphosphate binding to evaluate Galpha activation directly, we found for Galpha that no ligand tested, including 8-iso-prostaglandin F (8-iso-PGF2alpha and a purported antagonist (pinane thromboxane A2), was silent. The activity of agonists was especially pronounced when evaluated for TPalpha-Galpha13 and in the context of receptor reserve. Agonist activity for 8-iso-PGF2 was diminished and that for pinane thromboxane A nonexistent when Galpha12 was the reporter. These data establish that G12 and G13 can report differentially potency and efficacy and underscore the relevance of receptor and G protein context.

Animals↗
PubMed2006

Down-regulation of hepatoma-derived growth factor inhibits anchorage-independent growth and invasion of non-small cell lung cancer cells.

We recently reported that a high level of hepatoma-derived growth factor (HDGF) expression in tumors correlates with a high incidence of tumor relapse or distant metastasis and shortened survival time in patients with non-small cell lung cancer (NSCLC). However, the mechanisms of the HDGF-associated aggressive biological behavior are unknown. In this study, we knocked down HDGF expression in NSCLC cells to determine the biological consequences. Transfection with HDGF-specific small interfering RNA (siRNA) resulted in down-regulation of HDGF expression in four NSCLC cell lines. Down-regulation of HDGF resulted in no detectable effect on anchorage-dependent cell growth as determined with a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, a microelectronic cell sensor system, and flow cytometry. In contrast, cells transfected with HDGF-siRNA grew more slowly and formed significantly fewer colonies in soft agar than did cells treated with LipofectAMINE alone or transfected with negative control siRNA. In an in vitro invasion assay, significantly fewer cells transfected with HDGF-siRNA than cells treated with LipofectAMINE alone were able to invade across a Matrigel membrane barrier. In an in vivo mouse model, A549 cells treated with HDGF-siRNA grown significantly slower than the cells treated with LipofectAMINE alone or negative control siRNA. Morphologically, HDGF-siRNA-treated tumors exhibited markedly reduced blood vessel formation and increased necrosis, whereas the Ki67 labeling indices were similar in tumors treated with controls. Our results suggest that HDGF is involved in anchorage-independent growth, cell invasion, and formation of neovasculature of NSCLC. These qualities may contribute to the HDGF-associated aggressive biological behavior of NSCLC.

Animals↗
PubMed2006

Application of microdialysis to study the in vivo release of pingyangmycin from in situ gels in rabbits.

Microdialysis was used together with HPLC to monitor the local concentration of pingyangmycin hydrochloride (PYM) after embolizing rabbit ear-veins with an injectable sustained release formulation, PYM-Zein/PYM-Zein-sucrose acetate isobutyrate (SAIB), in situ gel. The dialysis probe was perfused at 2 microL/min. The in vivo recovery was 46.6 3.1% (n = 4). The samples were injected directly into HPLC. PYM was detected using UV detector at 291 nm. Separation from other components in the dialysate was performed using a Discovery((R)) RP-Amide C(16) column within 12 min. The response for PYM in the dialysate was linear (r(2) > 0.996) over the range of 2.5-212 microg/mL. The limit of detection and limit of quantitation of PYM in the dialysate were 0.4 and 1.5 microg/mL, respectively. The results demonstrated that the in situ gel of PYM-Zein-SAIB could extend the release of PYM to 4 days. SAIB could significantly cut down the initial burst of PYM from the in situ gels (p < 0.05).

Animals↗