Biomedical subjects

Qun Dong

Publications and source records attributed to Qun Dong.

14 recordsLinked to original sources

PubMed2006

A beta-D-glucan isolated from the fruiting bodies of Hericium erinaceus and its aqueous conformation.

HEP3, a beta-D-glucan slightly soluble in water, was isolated from the alkaline extract of the fruiting bodies of Hericium erinaceus. Its chemical structure was investigated by methylation analysis, periodate oxidation, Smith degradation and by IR and NMR spectroscopy. It was shown to have a main chain composed of beta-(1-->3)-linked D-glucopyranosyl residues, with single unit glucosyl branches attached to O-6 of every third backbone residue. Viscometry and Congo red reaction indicated that HEP3 has a highly ordered hydrogen-bond dependent conformation in aqueous solution, which collapses in strong alkaline solution.

Carbohydrate Conformation↗

PubMed2005

In situ depositing silver nanoclusters on silk fibroin fibers supports by a novel biotemplate redox technique at room temperature.

Evolvement of bioinspired approaches for the construction of well-ordered nanostructures is a crucial intersection of branches of materials science and biotechnology. In this paper, floriated clusters of silver nanocrystallites, which consist of polycrystalline grains about 5 nm in diameter, have been successfully prepared on silk fibroin fibers (SFFs) through an in situ biotemplate redox approach at room temperature. The reductive amino acid tyrosine of SFFs mainly provided both reduction and location functions under alkaline conditions and could reduce Ag(I) ions to Ag(0). Finally, stable silver nanoclusters were generated on SFF substrates. The morphologies of silver nanoclusters were mostly attributed to the concentration of silver nitrate solution as well as special configurations and structures of silk fibroin macromolecules. A possible mechanism was explored intensively for tyrosine-residue-based silver nanocrystal formation.

Animals↗

PubMed2005

[Isolation, purification and structural analysis of a polysaccharide MDG-1 from Ophiopogon japonicus].

AIM: To separate and purify the anti-myocardial ischemic polysaccharide fraction with a homogenous molecular weight from Ophiopogon japonicus, then study the chemical structure of the parts. METHODS: Crude polysaccharides were prepared by extracting the tube root fraction of Ophiopogon japonicus with water, then precipitation with ethanol. From the crude polysaccharides, the polysaccharide of MDG-1 was separated and purified using ultrafiltration, DEAE Sepharose FF and Sephadex G-25 column chromatography. Its structure was studied by complete hydrolysis, periodate oxidation, Smith degradation, methylation analysis, 1H NMR and 13C NMR analysis etc. RESULTS AND CONCLUSION: MDG-1 was a water-soluble beta-D-fructosan, containing a backbone composed of Fruf (2 --> 1), and a branch of Fruf (2 --> 6) Fruf (2 --> per average 2. 8 of main chain residues. Mn, Mw and Mp of MDG-1 were 3 400, 4 800 and 5 000, respectively. MDG-1 contains trace of Glc, which maybe connect to its reducing terminal. Molar ratio of Fru and Glc is approximately 35: 1.

Methylation↗

PubMed2004

Structural investigation of a novel rhamnoglucogalactan isolated from the fruiting bodies of the fungus Hericium erinaceus.

A new heteropolysaccharide (HEP-1) was isolated from the fruiting bodies of Hericium erinaceus. It was estimated to have a molecular weight of 1.8x10(4) da and showed [alpha](D)(20) +129 (c 0.295, H(2)O). HEP-1 is composed of rhamnose, galactose, and glucose in the ratio of 1.19:3.81:1.00. Its structural features were investigated using composition analysis, methylation analysis, partial hydrolysis, and IR and NMR spectroscopy. The results showed that HEP-1 has a (1-->6)-linked alpha-d-galactopyranosyl backbone with branches that are composed of rhamnose and glucose attached to O-2.

Basidiomycota↗

PubMed2004

A complex prescription for vitiligo activates mitochondrial ATP synthase-6 expression in B-16 murine melanoma cells.

A complex prescription (CP) used traditionally for the treatment of vitiligo was prepared from water extract of eight plant materials. To study the mechanism of this preparation its effect on gene expression of B-16 murine melanoma cells was estimated using differential display method (DDRT-PCR). The results showed that the complex prescription was effective in activating the mitochondrial ATP synthase-6 (ATPase-6) gene expression in B-16 murine melanoma cells. This activity may play an important role in its treatment of vitiligo.

Animals↗

PubMed2004

Structural analysis of a pectic polysaccharide from the leaves of Diospyros kaki.

A pectic polysaccharide DL-2A with a molar mass of 8.5 x 10(5), was obtained from the boiling water extract of Diospyros kaki leaves. It had [alpha]20D -21.8 degrees (c 0.22, H2O) and consisted of rhamnose, arabinose, galactose, xylose and galacturonic acid units in the molar ratio of 0.4:3.4:2.4:1.0:0.8, along with traces of glucuronic acid. About 16.7% of galacturonic acid existed as the methyl ester. A combination of linkage analyses, periodate oxidation, partial acid hydrolysis, selective lithium-degraded reaction, ESIMS, 1H- and 13C- NMR spectral analyses revealed its structural features. It was found that DL-2A possessed an alpha-(1-->4)-galacturonan backbone with some insertions of alpha-1,2-Rhap residues. The side-chains of arabino-3,6-galactan were attached to the backbone via O-4 of Rhap residues and O-3 of GalAp residues, while 4-linked xylose residues (forming short linear chains) were directly linked to O-4 of rhamnose residues, not as part of the xylogalacturonan. These novel structural features enlarge the knowledge on the fine structure of pectic substances in the plant kingdom.

Carbohydrate Conformation↗

PubMed2003

Structure and potential immunological activity of a pectin from Centella asiatica (L.) Urban.

S3A was a RG-I pectin isolated from Centella asiatica that contained Rha, Ara, Gal, Glc and GalA in molar ratio of 1.0:0.6:1.5:0.2:1.1 and had been found to have a backbone composed mainly of the disaccharide repeat unit, -->4)-alpha-D-GalpA-(1-->2)-alpha-L-Rhap-(1-->. Based on methylation analysis, NaIO4 oxidation, partial acid hydrolysis and lithium-treatment, the structural features were elucidated. Side chains of S3A were predominantly linked to O-4 of 1,2,4-linked alpha-L-Rhap. The side chains are comprised of arabinosyl chains, galactosyl chains, arabinogalactosyl chains and short glucosyl chains. A total of 45% Rhap in the backbone was substituted by side chains. The arabinosyl residues were mostly distributed in the arabinosyl side chains. According to the immunological results of S3A and its degraded derivatives, S3A had no immunological activity, but its derivatives had immuno-stimulating activities to some extent.

Animals↗

PubMed2003

Structural features of a pectic arabinogalactan with immunological activity from the leaves of Diospyros kaki.

A water-soluble acidic heteroglycan, DL-3Bb, isolated from the leaves of Diospyros kaki, had [alpha](D)(20) -19.9 degrees (c 0.30, water), and contained rhamnose, arabinose, xylose, galactose and galacturonic acid in the molar ratio of 1.0:4.5:0.7:1.5:1.0. About 44% of the galacturonic acid existed as its methyl ester, and O-acetyl groups (approx 5.7%) were also identified. Its molecular weight was determined to be 9.0x10(5) Da by high-performance gel-permeation chromatography. Its structural features were elucidated by a combination of methylation analysis, periodate oxidation, two steps of partial acid hydrolysis, and 1H and 13C NMR spectroscopy and ESI mass spectrometry. The data obtained indicated that DL-3Bb possessed a backbone of a disaccharide of [-->4)-alpha-GalAp-(1-->2)-alpha-Rhap-(1-->], with approx 58.7% substitution at O-4 of the rhamnopyranosyl residues by beta-(1-->4)-linked xylopyranosyl residues, and by beta-(1-->3) and beta-(1-->6)-linked galactopyranosyl (galactan) residues. The side chains were further substituted by arabinofuranosyl residues at O-2 by beta-(1-->4)-linked xylopyranosyl residues and at O-3 by beta-(1-->6)-linked galactopyranosyl residues. Preliminary tests in vitro revealed that it could stimulate LPS-induced B lymphocyte proliferation, but not for ConA-induced T lymphocyte proliferation. It was proposed that the acid-labile arabinofuranosyl residues in the side chains would not be needed for the expression of the enhancement of the immunological activity, and that the presence of GalAp in the backbone has an important, but not crucial effect on the expression of the activity.

Animals↗

PubMed2003

Epithelioid variant of gastrointestinal stromal tumor: Diagnosis by fine-needle aspiration.

Epithelioid gastrointestinal stromal tumors (GISTs) may cause significant diagnostic confusion on fine-needle aspiration (FNA) with carcinomas, neuroendocrine tumors, and melanoma, particularly when metastatic. This study characterizes the cytologic features of nine cases of epithelioid GISTs that were obtained by computerized tomographic guidance in five, by endoscopic ultrasound in three, and from an excised liver tumor in one. Six cases presented as liver masses, one as a perisplenic mass, one as an abdominal mass, and one as a gastric mass. The aspirates revealed mainly single or small clusters of epithelioid cells with a moderate amount of granular to clear cytoplasm, small uniform nuclei with mild to marked nuclear envelope irregularities. Binucleation and intranuclear inclusions were frequent findings. Collagenous stroma was seen in most cases. In three cases, a neuroendocrine tumor was the initial diagnosis. Immunocytochemical staining for c-kit (CD117) was performed on cellblocks in six cases and was positive in five cases. On the subsequent surgical specimen, CD117 was positive in the c-kit-negative cytology case. The diagnosis of GIST should be considered in aspirates of the gastrointestinal tract, liver, mesentery, or abdominal wall mass lesions when epithelioid cells are the predominant cell type. Ancillary studies such as immunohistochemical stains are usually helpful in making a definitive diagnosis.

Adult↗

PubMed2003

Loss of cables, a novel gene on chromosome 18q, in ovarian cancer.

Cables, a cyclin-dependent kinase (cdk) interacting protein, has recently been identified and mapped to human chromosome 18q11. Cables appears to be primarily involved in cell cycle regulation and cell proliferation. Overexpression of Cables in Hela and other cell lines inhibits cell proliferation and tumor formation. We hypothesize that loss of Cables expression is associated with ovarian cancer. To test our hypothesis, we examined Cables expression in the four most common subtypes of ovarian carcinomas: serous, endometrioid, mucinous, and clear cell. In addition, mucinous and serous borderline tumors were also included. Loss of Cables expression was observed at high frequency in ovarian serous (11 of 14 cases, 79%) and endometrioid (5 of 10 cases, 50%) carcinomas. In contrast, strong Cables staining was detected in all clear cell carcinomas (10 cases) and mucinous tumors (5 carcinomas and 5 borderline tumors). The majority of serous borderline tumors (11 of 14 cases, 79%) showed positive Cables staining, with the rest showing focal loss of Cables expression. Furthermore, RT-PCR revealed the lack of Cables mRNA in a human ovarian cancer xenograft. No correlation was noted between loss of Cables and histologic grade, tumor stage, and survival. In conclusion, our results indicate that loss of Cables is common in ovarian serous and endometrioid carcinomas and imply that Cables may be involved in the pathogenesis of these two types of ovarian carcinomas.

Adenocarcinoma, Clear Cell↗

PubMed2002

Structural characterization of a water-soluble beta-D-glucan from fruiting bodies of Agaricus blazei Murr.

A beta-D-glucan, Ab2-2N, was isolated from the hot-water extract of fruiting bodies of Agaricus blazei Murr by ethanol precipitation, anion-exchange and gel-permeation chromatography. Its structure was investigated by composition analysis, methylation analysis, Smith degradation, mild hydrolysis, and NMR spectroscopy. It contains a (1-->6)-linked beta-D-glucopyranosyl backbone, with one side chain consisting of terminal and 3-substituted beta-D-glucopyranosyl residues attached at O-3 for every three backbone residues.

Agaricus↗

PubMed2002

Structural features of immunologically active polysaccharides from Ganoderma lucidum.

Three polysaccharides, two heteroglycans (PL-1 and PL-4) and one glucan (PL-3), were solubilized from the fruit bodies of Ganoderma lucidum and isolated by anion-exchange and gel-filtration chromatography. Their structural features were elucidated by glycosyl residue and glycosyl linkage composition analyses, partial acid hydrolysis, acetolysis, periodate oxidation, 1D and 2D NMR spectroscopy, and ESI-MS experiments. The data obtained indicated that PL-1 had a backbone consisting of 1,4-linked alpha-D-glucopyranosyl residues and 1,6-linked beta-D-galactopyranosyl residues with branches at O-6 of glucose residues and O-2 of galactose residues, composed of terminal glucose, 1,6-linked glucosyl residues and terminal rhamnose. PL-3 was a highly branched glucan composed of 1,3-linked beta-D-glucopyranosyl residues substituted at O-6 with 1,6-linked glucosyl residues. PL-4 was comprised of 1,3-, 1,4-, 1,6-linked beta-D-glucopyranosyl residues and 1,6-linked beta-D-mannopyranosyl residues. These polysaccharides enhanced the proliferation of T- and B-lymphocytes in vitro to varying contents and PL-1 exhibited an immune-stimulating activity in mice.

Adjuvants, Immunologic↗

PubMed2002

Blood substitutes. What they are and how they might be used.

Three classes of materials have been studied as potential blood substitutes: modified hemoglobin solutions, perfluorocarbon emulsions, and liposome-encapsulated hemoglobin. The first two have reached phase III clinical trials, while the third remains in the preclinical state of testing. Hemoglobin is a highly active molecule; hence, modification has been required to avoid potential deleterious effects. Although there has been considerable progress toward bringing such a product to the clinical setting, its development has challenged our understanding of oxygen delivery and use. The perfluorocarbon emulsions have been studied primarily for roles other than as equivalents of conventional banked units of RBCs for transfusion. The study of these molecules has added to our understanding of basic physiologic processes.

Animals↗

PubMed2000

Structure and Conformation Behavior of a Glucan from Spores of Ganoderma lucidum (Fr.) Karst.

A novel polysaccharide designated as beta-D-glucan LB-NB, [alpha](D)(21) -24.52(0)(c =0.81, H(2)O)and Mr 4.7x10(4), was isolated and purified from a 0.5 mol/L sodium hydroxide extract of the sporoderm-broken spores of Ganoderma lucidum. The results of NMR experiments, total hydrolysis, methylation analysis and Smith degradation of LB-NB showed that it possesses a backbone consisting of(1right curved arrow 3)- beta-D-glucosyl residues, about two out of nine glucosyl residues being substituted at O-6 by single glucosyl groups. The conformational behavior of LB-NB was studied. Measurements by specific rotations and viscometry showed that the glucan LB-NB takes an ordered structure in water or lower concentration(<0.05 mol/L)alkaline solution and dissolves as random coil in higher concentration(>0.1 mol/L)alkaline solution or in dimethyl sulfoxide(Me(2)SO). The ordered conformation melts into flexible chains with the increase of the concentration of alkali or the V(DMSO)(v/v)of H(2)O-Me(2)SO mixture. The former dissociation is reversible and the later is irreversible. The complex-formation with Congo red indicated that the LB-NB takes neither triple-stranded helical nor randomly coiled conformation in neutral or slightly alkaline solution, and most probably, it should contain single helical structure in aqueous solution. According to immunological test, the LB-NB showed remarkable activity of stimulating the proliferation of T-Cells in vitro, giving a good example for Kulicke's statement.

Journal Article↗