Biomedical subjects

Hong Zhang

Publications and source records attributed to Hong Zhang.

520 records · Page 29Linked to original sources

PubMed1999

Image Fusion System Using PACS for MRI, CT, and PET Images.

This paper presents and evaluates Picture Archiving and Communication System (PACS) and its interaction with the image fusion applications using positron emission tomography (PET), CT, and MRI, as well as some clinical applications of fusion images. A network connections between medium-sized PACS involving CT, MRI, SPECT, and PET were developed. Image registration and fusion was achieved in the PET's workstation by Advanced Visual System (AVS) software. Reconstructed datasets of CT, MRI, SPECT, and PET were transferred and archived in PACS servers. Series of anatomical images of CT and MRI were fused with metabolical images of PET with (18)F labeled fluoro-2-deoxy-D-glucose (FDG). Throughput rate of image data, as well as clinical applications of fusion images were evaluated and correlated with phantom studies. The average throughput rate of archiving and processing steps was 0.45 Mbps, 0.77 Mbps, respectively. Image fusion experiment using phantom and patients' data showed high accuracy in all directions. The combination of PACS and image fusion provided very useful clinical tools and made it quite easy to maximize the benefit from the diagnostic imaging.

Journal Article↗

PubMed1999

Structure of Cytoplasmic Polyhedrosis Virus from Bombyx mori.

The structures of full and empty capsids of CPV were studied by negative staining and electron cryomicroscopy and computer reconstruction techniques. By comparing the structures and biochemical compositions, the CPV was identified as a single-layered capsid with its five structural proteins located on it. This single capsid is arranged according to T=1 icosahedral symmetry with 12 turret-like spikes at its icosahedral vertices. The empty and full CPV show identical capsid but differ inside. The dense and ordered genomic dsRNA is located inside the full CPV. The internal space of the empty CPV has almost no electron density except for 12 electron densities attributed the transcriptional enzyme complexes extending inward from the base part of CPV spikes.

Journal Article↗

PubMed1998

Crystal Engineering in [(12C4)(2)Na][Cd(SCN)(3)]: First Example of an Anionic Cadmium Thiocyanate Coordination Solid with a Sandwich [(12C4)(2)Na](+) Cation as Spacer/Controller, Resulting in a Hexagonal Arrangement of Antiparallel Zigzag [Cd(SCN)(3)(-)](infinity) Chains.

This paper reports the synthesis, characterization, and structure of [(12C4)(2)Na][Cd(SCN)(3)] (3). The title compound 3 represents the first example of an anionic cadmium thiocyanate coordination solid in which a sandwich [(12C4)(2)Na](+) monocation serves as the spacer/controller, giving rise to a hexagonal array of antiparallel infinite zigzag [Cd(SCN)(3)(-)](infinity) chains with the cations occupying the triangular channels. The title compound 3 crystallizes in a monoclinic unit cell of P2(1)/n space group symmetry with lattice parameters of 13.204(2) Å, 10.692(2) Å, 21.036(1) Å, 95.520(8) degrees, and Z = 4. A detailed comparison of the title structure (3) with that of [(18C6)(2)Na(2)(H(2)O)(2)](1/2)[Cd(SCN)(3)] (1) and [(18C6)K][Cd(SCN)(3)] (2) revealed that the arrangement and the alignment of the infinite anionic [Cd(SCN)(3)(-)](infinity) zigzag chains are dictated by the dimensions and symmetry, respectively, of the cations. The infinite anionic [Cd(SCN)(3)(-)](infinity) chains in 1 and 2 form an approximate tetragonal array, creating square channels which are filled with the dimeric [(18C6)(2)Na(2)(H(2)O)(2)](2+) (in 1) or with two monomeric [(18C6)K](+) (in 2) cations while the infinite anionic [Cd(SCN)(3)(-)](infinity) chains in 3 adopt an approximate hexagonal arrangement with the triangular channels filled by the smaller [(12C4)(2)Na](+) cations (the dimension effect). The relative alignment (either parallel or antiparallel) of the anionic chains is dictated by the symmetry or approximate symmetry of the cations. Thus, both the dimeric cation in 1 and the sandwich cation in 3 give rise to antiparallel alignment of the anionic [Cd(SCN)(3)(-)](infinity) chains with the centrosymmetric space group P2(1)/n whereas the disklike cation in 2 gives rise to parallel alignment of [Cd(SCN)(3)(-)](infinity) chains with noncentrosymmetric space group Cmc2(1) (the symmetry effect).

Journal Article↗

PubMed1998

Expression and kinetic changes of alkaline phosphatase and its isoenzymes in experimental rat hepatoma.

AIM:To explore the expression and changes of hepatoma specific alkaline phospatase (ALP) in rats during canceration.METHODS:The ALPs and isoenzymes of rat livers and sera were investigated in SD hepatomas induced with 0.05% 2-fluoenylacetamide (2-FAA).RESULTS: By pathological examination and biochemical analysis. ALPs were overexpressed in rat livers during canceration and then were secreted into blood. Serum total ALP activities, liver ALP specific activities (U/g) including soluble and membrane-combined ALP activities of each group were all significantly higher (P < 0.01)than those of control group. The average ratios of soluble ALP to membrane-combined ALP were increased significantly after 6 weeks. ALP isoenzymes of rat sera and livers showed 5 bands on PAGE:ALP-I and ALP-II were specific for normal liver and rat hepatoma tissues, the ALP-II appeared in rat liver after 6 weeks and in sera after 8 weeks.CONCLUSION:ALP with carcino-embryonic protein was overexpressed in hepatoma tissues; the abnormal ALP-II of ALP isoenzymes in sera and liver of rats can be used as a tumor marker for early diagnosis of rat hepatoma.

Journal Article↗

PubMed1997

Isolation and Partial Purification of Two Types of Nuclear Tyrosine Protein Kinase from Rat Liver.

Nuclear tyrosine protein kinase (n-TPK) plays an important role in the regulation of cell cycle and gene transcription. In the present investigation, two types of n-TPK isozyme, n-TPK I and n-TPK II were isolated from the nuclear extract of rat liver by using DEAE-Sepharose CL-6B ion-exchange column chromatography. The two isozymes were further partially purified on heparin affinity column and Sephadex G-100 to 30 and 25 folds respectively. The specific activities of n-TPK I and n-TPK II were 1 638 and 1 360 pmol/(min.mg protein) respectively. By means of Sephadex G-100 chromatography and autoradiography of the autophosphorylated n-TPK after [32P]-ATP labeling and SDS-PAGE, the molecular weight of n-TPK I and n-TPK II were determined to be 76 kD and 59 kD respectively. Both n-TPK isozymes are monomers.

Journal Article↗

PubMed1990

The predicted and observed decline in onchocerciasis infection during 14 years of successful control of Simulium spp. in west Africa.

In 55 villages from the well-protected central area of the Onchocerciasis Control Programme in West Africa (OCP), skin snip surveys have been carried out at regular intervals since the programme started, and the latest round of surveys was undertaken after 12-14 years of successful vector control. The observed trends in the prevalence and intensity of onchocerciasis infection in cohorts of adults were compared with the trends predicted using a host-parasite model. After 12-14 years of control the community microfilarial load (CMFL) was close to zero in all villages. During the last few years of control, the prevalence of infection declined at an accelerated rate, and this was predicted by the model. There was generally good agreement between observed and predicted trends. The predictions were based on an estimated average duration of infection of 10.4 years, which corresponds to a mean reproductive lifespan for Onchocerca volvulus of 9-9.5 years, and an upper limit of 15 years for 95% of the infections. Differences between the observed and predicted data included the trend in CMFL between the first and second surveys, which in 18 villages did not show the predicted decline. Furthermore, the observed final decline in prevalence was faster than predicted in the north-eastern part of the central OCP area. After 14 years of vector control, the level of onchocerciasis has fallen to such a low level that consideration is being given to ending larviciding.

Adult↗

PubMedDate not supplied

Charging compensation of alumina samples by using an oxygen microinjector in the environmental scanning electron microscope.

A gas microinjector system was set up in an environmental scanning electron microscope (ESEM) to create an oxygen atmosphere around the alumina samples for the charging compensation under a pressure between 2 x 10(-5) Pa approximately 2 x 10(-2) Pa. At low pressures, the skirt effect of the electron scattering can be degraded, which results in improvement of the imaging contrast and increase of the signal/noise ratio. The sample current (I(SC)) and the Duane-Hunt limit were measured to evaluate the charging effect.

Journal Article↗

PubMedDate not supplied

Diversity of endogenous small non-coding RNAs in Oryza sativa.

Small non-coding RNAs play important roles in regulating cell functions by controlling mRNA turnover and translational repression in eukaryotic cells. Here we isolated 162 endogenous small RNA molecules from Oryza sativa, which ranged from 16 to 35 nt in length. Further analysis indicated that they represented a diversity of small RNA molecules, including 17 microRNAs (miRNAs), 30 tiny non-coding RNAs (tncRNAs) and 20 repeat-associated small interfering RNAs (rasiRNAs). Among 17 miRNAs, 13 were novel miRNA candidates and their potential targets were important regulatory genes in the rice genome. We also found that a cluster of small RNAs, including many rasiRNAs, matched to a nuclear DNA fragment that evolutionarily derived from chloroplast. These results demonstrate clearly the existence of distinct types of small RNAs in rice and further suggest that small RNAs may control gene regulation through diverse mechanisms.

Base Sequence↗

PubMedDate not supplied

Oncological diagnosis using (11)C-choline-positron emission tomography in comparison with 2-deoxy-2-[(18)F] fluoro-D-glucose-positron emission tomography.

PURPOSE: To assess and compare the usefulness of (11)C-Choline-positron emission tomography (PET) with that of 2-deoxy-2-[(18)F]fluoro-D-glucose (FDG)-PET for the differentiation between benign and malignant in various tumors. MATERIALS AND METHODS: We examined 38 consecutive patients with various tumors, including seven patients with brain tumors, two with oral cavity tumor, two with esophageal cancer, six with lung cancer, 11 with bone tumor, nine with soft tissue tumors, and one with myeloma. (11)C-Choline-PET and FDG-PET were performed from five minutes and 40 minutes, respectively, after injection of 275-455 MBq tracer. Tracer uptakes were evaluated by the standardized uptake value (SUV) and were analyzed in according to the pathologic data. RESULTS: (11)C-Choline uptake in malignancies (3.9 +/- 1.7, n=24) was significantly higher than that in benign lesions (1.7 +/- 1.2, n=14) (P < 0.0001). On the other hand, the FDG uptake in malignancies was 4.9 +/- 2.0 (n=24) and was also significantly larger than that in benign lesions 1.6 +/- 1.3 (n=14) (P < 0.0001). The (11)C-Choline uptake in all the lesions correlated with FDG uptake (r=0.658, P < 0.02, n=38). According to the receiver operating characteristic (ROC) analysis, the area under the ROC curve for (11)C-Choline-PET was 0.871, and with no significant difference compared to FDG-PET with the area of 0.929. CONCLUSIONS: This study demonstrated that (11)C-Choline-PET is similar to FDG-PET in differentiation between malignant and benign lesion in various tumors.

Adolescent↗

PubMedDate not supplied

Common structural properties specifically found in the CSalphabeta-type antimicrobial peptides in nematodes and mollusks: evidence for the same evolutionary origin?

The structural properties of the Ascaris suum antibacterial factor (ASABF)-type antimicrobial peptides, isolated from nematodes, were compared with the CSalphabeta-type antimicrobial peptides found in other organisms. The spacing of the half-cystine residues, cysteine pairings, and organization of the precursor were different from the 'classical' CSalphabeta-type antimicrobial peptides, such as drosomycin and plant defensins, and identical only to the MGD and myticin in mollusks. In addition, ABF-5, a member of the ASABF-type antimicrobial peptides in Caenorhabditis elegans, is predicted to contain a basic mature region and an acidic pro-region, similar to MGD and myticin. These results suggest that the ASABF-type antimicrobial peptides, MGD and myticin are similar in their structure.

Animals↗

PubMedDate not supplied

Role of the Raf/MEK/ERK and the PI3K/Akt(PKB) pathways in fibroblast senescence.

Replicative senescence is characterized by numerous phenotypic alterations including loss of proliferative capacity and numerous changes in gene expression such as impaired serum inducibility of the immediate early gene c-fos and increased expression of collagenase. Transcription of c-fos in response to mitogens depends on the activation of a multiprotein complex formed on the c-fos serum response element (SRE), which includes the transcription factors serum response factor (SRF) and ternary complex factor (TCF). TCF is activated after phosphorylation by the Extracellular signals Regulated Kinase 1 and 2 (ERK1/2), two kinases of the Raf/MEK/ERK signaling pathway. We have previously demonstrated that collagenase expression is under positive regulation by the transcription factor FKHRL1 and that this transcription factor is under negative regulation by the phosphatidylinositol 3-kinase(PI3K)/Akt(PKB) pathway. Although total activity of ERK and Akt was similar in total cell lysates from early and late passage fibroblasts our data indicate that in senescent cells neither ERK nor Akt are able to phosphorylate efficiently their nuclear targets. Our findings suggest that although they can be fully activated in the cytosol of both early and late passage cells, the Raf/MEK/ERK and the PI3K/Akt pathways, which are essential for cellular proliferation, are down regulated in the nuclei of senescent cells.

Blotting, Western↗

PubMedDate not supplied

The effect of glucose levels on fetal birth weight: a study of Chinese gravidas in Tianjin, China.

The relationship between maternal glucose intolerance and fetal birth weight remains, to a large extent, unknown in Chinese gravidas. From December 1998 to December 1999, 9471[corrected] women in six urban districts of Tianjin, China, underwent an initial screening using a 50-g, 1-h glucose load at 26-30 gestational weeks. Women with a serum glucose reading >or=7.8 mmol/l, were followed up for a 75-g, 2-h glucose tolerance test, which was interpreted using the 1998 World Health Organization's (WHO) criteria for diabetes. A total of 174 women had gestational diabetes mellitus. Complete data was collected in 170 women. Among them, 56 accepted diabetes management including self-home glucose monitoring, diet, and physical activity advice, and others received no treatment. The comparison group was 302 women with normal glucose tolerance (NGT). Glucose levels at the initial screening (partial R(2)=.0343, P<.0001), maternal weight gain during pregnancy (partial R(2)=.0915, P<.0001), and gestational week at delivery (partial R(2)=.0432, P<.0001) were determinants of fetal birth weight, controlling for maternal age, pregravid BMI, maternal stature, and other confounders. Both gestational diabetes mellitus (GDM) status and a positive screening but normal oral glucose tolerance test (OGTT) result were predictors of macrosomia (birth weight >or=4000 g). It concludes that maternal glucose levels correlate with fetal birth weight and a glucose level of 7.8 mmol/l or more at the initial screening is predictive of macrosomia in Chinese gravidas regardless of GDM status.

Adult↗

PubMedDate not supplied

Monodisperse chitosan nanoparticles for mucosal drug delivery.

Chitosan nanoparticles (CS NPs) of a controlled size (below 100 nm) and narrow size distribution were obtained through the process of ionic gelation between CS and sodium tripolyphosphate (TPP). A high degree of CS deacetylation and narrow polymer molecular weight distribution were demonstrated to be critical for the controlling particle size distribution. Properties of the CS NPs were examined at different temperatures, values of pH, and ratios of CS to TPP. The model protein, bovine serum albumin, was encapsulated into the NPs, and the in vitro release profiles were examined in physiologically relevant media at 37 degrees C.

Animals↗

PubMedDate not supplied

Effect of exogenous wild-type p53 on melanoma cell death pathways induced by irradiation at different linear energy transfer.

We investigated the effect of exogenous wild-type p53 on the radiation-induced cells apoptosis and necrosis at different levels of linear energy transfer (LET) to evaluate its mechanisms. The human melanoma cell line A375, which bears wild-type p53 gene status, was used, as well as the transfectant A375 cells (A375/p53) with adenoviral vector containing the wild-type p53 gene. We exposed these cells to X-rays and to accelerated carbon-ion (C-) beams. Cellular sensitivities were determined by using clonogenic assay. Apoptotic and necrotic cell deaths were determined morphologically by dual staining (acridine orange and ethidium bromide) using fluorescence microscopy. We discovered that (1) there was no significant difference in survival fraction between A375 cells and A375/p53 cells irradiated by C-beams with greater than 32 KeV/microm LET, (2) although apoptosis in the two kinds of cells increased in an LET-dependent manner, exogenous wild-type P53 induced cell apoptosis efficiently in A375/p53 relative to A375 cells with X-rays or high-LET irradiation, and (3) by high-LET irradiation, the number of necrosis in A375 cells increased significantly (P < 0.05) in comparison with A375/p53 cells. These results indicate that in high-LET irradiation apoptosis induction is p53 dependent partly and exogenous wild-type P53 plays an important role in modulating cell death type, although there was no significant difference in cellular radiosensitivities. Our observation in the study offers the potential application of high-LET radiation combined with p53 in the management of human patients with melanoma.

Apoptosis↗

PubMedDate not supplied

Mouse epididymal Spam1 (pH-20) is released in the luminal fluid with its lipid anchor.

Previously we demonstrated that the murine sperm adhesion molecule 1 (Spam1 or PH-20) is synthesized by the epididymal epithelium, preferentially in the distal region, and is released into the luminal fluid. We also showed that whereas testicular and epididymal Spam1 have hyaluronidase activity at neutral pH, they are under different transcriptional regulation. The aim of this study was to further compare characteristics of the two forms of this glycosyl-phosphatidylinositol-linked protein and their transcripts, and to determine whether secreted epididymal Spam1 is released with its lipid anchor. With GeneRacer amplification of the 3' end of the complementary DNA we show that the poly(A) tails are significantly (P <.05) shorter in the epididymis than in the testis. Two-dimensional polyacrylamide gel electrophoresis with immunoblotting reveals one to three isoforms for epididymal Spam1 with the isoelectric point (pl) ranging from 7.3 to 9.0, and four isoforms ranging from 6.6 to 9.0 pl for testicular Spam1. Two isoforms with a pl ranging from 7.6 to 9.0 were observed for caudal sperm. Lectin blotting analysis shows that Phaseolus vulgaris erythroagglutinin, Lycopersicon esculentum lectin (LEL), and Solanum tuberosum lectin, which all bind to N-linked chains, recognize a 67 kd band in the epididymis and caudal sperm, but not in the testis. Treatment of the protein extracts with anti-Spam1 serum prior to blotting with LEL led to the disappearance of the banding, indicating Spam1 specificity of the staining. The lectin peanut agglutinin, which preferentially binds to O-linked side chains, recognizes a 67 kd band in all three cell types. Enzymatic deglycosylation studies confirmed the presence of an O-linked glycan in all three cell types. Ultracentrifugation of the luminal fluid reveals that epididymal Spam1 is secreted predominantly as insoluble particles, which when treated with phosphatidylinositol-specific phospholipase C or Triton X-100, reveal that the majority of epididymal Spam1 is released with its lipid anchor, a form in which it can bind to sperm.

Animals↗

PubMedDate not supplied

Microsatellite instability and MBD4 mutation in unselected colorectal cancer.

BACKGROUND: We investigated the prognostic significance of microsatellite instability (MSI) and the association with clinicopathological factors in colorectal cancer, and further identified MBD4 mutations and their clinicopathological significance. PATIENTS AND METHODS: MSI was analyzed in 201 colorectal cancers. Sequencing analysis of MBD4 was performed in 26 MSI and 28 microsatellite stable (MSS) tumors. RESULTS: Twenty-seven tumors (13.4%) were MSI but did not correlate with improved survival. MSI was significantly correlated with proximal colon tumors (p < 0.001), poor differentiation or mucinous type (p = 0.005) and multiple tumors (p = 0.04). MBD4 mutations were found in 15% MSI but not in MSS tumors. The mutated cases showed female overrepresentation, proximal site and poorly-differentiated/mucinous type. CONCLUSION: MSI was not correlated with survival, but shared other features associated with MSI in colorectal cancer as demonstrated by others. The clinicopathological variables associated with the MBD4 mutations were probably the reflection of MSI features.

Aged↗