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Y H Dong

Publications and source records attributed to Y H Dong.

At least 19 recordsLinked to original sources
PubMed2006

Ancient paddy soils from the Neolithic age in China's Yangtze River Delta.

Identifying prehistoric irrigated rice fields and characterizing the beginning of paddy soil development are important for a better understanding of human development and agricultural history. In 2003, paddy soils and irrigated rice fields buried at a depth of 100-130 cm were excavated at Chuo-dun-shan in the Yangtze River Delta, close to Suzhou, China. The fields of sizes between 1.4 and 16 m(2) were surrounded with ridges that were connected to ditches/ponds via outlets to control the water level within the fields. Many carbonized and partly carbonized rice grains with an age of 3,903 B.C. (measured (14)C age 5,129+/-45 a BP) were recovered. The surface layers of these buried paddy fields showed a high content of soil organic matter and a considerable high density of rice opals. The latter were identified to derive from Oryza spp. Solid-state (13)C nuclear magnetic resonance spectroscopy revealed aromatic carbon (C) as the predominant organic C form in the fossil surface layer. This is expected, if the major source represents burnt rice and straw. In summary, our data are in agreement with new evidences indicating that in China, paddy soils and irrigated rice cultivation were initiated and developed more than 6,000 years ago.

Archaeology↗
PubMed2001

Quenching quorum-sensing-dependent bacterial infection by an N-acyl homoserine lactonase.

Bacterial cells sense their population density through a sophisticated cell-cell communication system and trigger expression of particular genes when the density reaches a threshold. This type of gene regulation, which controls diverse biological functions including virulence, is known as quorum sensing. Quorum-sensing signals, such as acyl-homoserine lactones (AHLs), are the essential components of the communication system. AHLs regulate virulence gene expression in a range of plant and animal (including human) bacterial pathogens. AHL-producing tobacco restored the pathogenicity of an AHL-negative mutant of Erwinia carotovora. Different bacterial species may produce different AHLs, which vary in the length and substitution of the acyl chain but contain the same homoserine lactone moiety. Here we show that the acyl-homoserine lactonase (AHL-lactonase), a new enzyme from Bacillus sp., inactivates AHL activity by hydrolysing the lactone bond of AHLs. Plants expressing AHL-lactonase quenched pathogen quorum-sensing signalling and showed significantly enhanced resistance to E. carotovora infection. Our results highlight a promising potential to use quorum-sensing signals as molecular targets for disease control, thereby broadening current approaches for prevention of bacterial infections.

4-Butyrolactone↗
PubMed2000

AiiA, an enzyme that inactivates the acylhomoserine lactone quorum-sensing signal and attenuates the virulence of Erwinia carotovora.

N-acylhomoserine lactones, known as autoinducers (AIs), are widely conserved signal molecules present in quorum-sensing systems of many gram-negative bacteria. AIs are involved in the regulation of diverse biological functions, including expression of pathogenic genes in the plant pathogens Pseudomonas solanacearum, several Erwinia species, and the human pathogen Pseudomonas aeruginosa. A bacterial isolate, Bacillus sp. 240B1, is capable of enzymatic inactivation of AIs. The gene (aiiA) for AI inactivation from Bacillus sp. 240B1 has been cloned and shown to encode a protein of 250 amino acids. Sequence alignment indicates that AiiA contains a "HXHXDH" zinc-binding motif that is conserved in several groups of metallohydrolases. Site-directed mutagenesis showed that conserved aspartate and most histidine residues are required for AiiA activity. Expression of aiiA in transformed Erwinia carotovora strain SCG1 significantly reduces the release of AI, decreases extracellular pectolytic enzyme activities, and attenuates pathogenicity on potato, eggplant, Chinese cabbage, carrot, celery, cauliflower, and tobacco. Our results indicate that the AI-inactivation approach represents a promising strategy for prevention of diseases in which virulence is regulated by AIs.

4-Butyrolactone↗
PubMed2000

MDH1: an apple homeobox gene belonging to the BEL1 family.

Differential display was used to isolate genes differentially expressed early in fruit development of apple (Malus domestica Borkh.). This approach resulted in the isolation of MDH1, a homeobox gene with a homeodomain similar to that of BELL1 (BEL1), which is involved in regulation of ovule development in Arabidopsis. However, outside the homeodomain MDH1 is quite different from BEL1. In apple, MDH1 mRNA was predominantly found in flowers, expanding leaves and expanding fruit. In pre-anthesis flowers, in situ hybridization showed that MDH1 mRNA accumulated in ovules. To further investigate the function of this new homeobox gene, MDH1 was transformed into Arabidopsis thaliana under the control of the cauliflower mosaic virus 35S promoter. The transgenic Arabidopsis plants showed dwarfing, reduced fertility and changes in carpel and fruit (silique) shape. The size and shape of the cells in the transgenic fruit was irregular. Both the transgenic phenotypes in Arabidopsis and the expression pattern of this gene in apple are consistent with the idea that MDH1 is likely to play an important role in control of plant fertility.

Amino Acid Sequence↗
PubMed1996

A multimodal approach for diagnosing patients with acute promyelocytic leukaemia.

A practical and efficient multi-modal protocol for processing specimens for patients referred with a question of acute promyelocytic leukaemia (APL) is described. The initial analysis comprises haematological evaluation of the bone marrow and peripheral blood smears using Romanowsky-stained slides. Concomitantly, a sample is processed for direct preparation as well as 1- and 2-day unstimulated cultures using conventional cytogenetic techniques. Communication between the cytogenetic and haematological laboratories is of critical importance so that the optimal conditions for culture (i.e. longer term versus unstimulated overnight and direct preparations) for the cytogenetic detection of chromosome rearrangements can be selected. The likelihood of detecting the characteristic translocation of APL, t(15;17), is enhanced in a longer term culture versus unstimulated overnight and direct preparations. Fluorescent in situ hybridization (FISH), utilized as an adjunct to GTG-banding, was found to be a powerful technique for detecting the t(15;17), especially where the GTG-banded preparation was of suboptimal quality. Results of five recent representative cases of APL are described to illustrate a practical approach which can be adapted by any clinical pathology laboratory.

Adolescent↗
PubMed1993

An experimental study and clinical pilot trials on yttrium-90 glass microspheres through the hepatic artery for treatment of primary liver cancer.

BACKGROUND: Yttrium-90 (90-Y) glass microsphere is a new kind of radiation microsphere for internal radiation therapy of primary liver cancer (PLC). The study was carried out by administration of 35 microns nondegradable 90-Y glass microsphere through the hepatic artery for treatment of PLC. METHODS: Six rabbits were injected with 185-1480 megabecquerels (MBq) of 90-Y glass microspheres, and three rabbits were injected with 35-300 mg of 89-Y glass microspheres for the toxic test. Eighteen patients received 2442-5550 MBq of 90-Y glass microspheres for the treatment of PLC. Whole blood counts, liver function, and imaging examination were performed. Pathologic examinations were performed on all rabbits. RESULTS: All rabbits were apparently well after absorbing 114.1-845.2 Gy 90-Y glass microspheres in the liver but showed transient degeneration of hepatocytes and portal fibrosis histologically. The mean absorbed dose in liver tissue of patients with PLC was 30.33 Gy, whereas that in tumor tissue was 88 Gy and the highest in tumor tissue, 186.36 Gy. The mean tumor:liver tissue ratio was 3:1; the highest, 14:1. Fourteen patients were still alive after half a year's follow-up and 6 of these 14 were still alive after 1 year. CONCLUSIONS: The rabbits could tolerate up to eight-fold of the upper limit of clinical dose (100 Gy). Good responses to the radiation therapy of 90-Y glass microspheres in patients with localized and hypervascular or vascular mass were achieved. Contraindications for the therapy were presence of massive hepatic arterioportal shunt and cancer emboli in the main portal vein. It is safe and applicable to deliver 90-Y glass microspheres in large doses through the hepatic artery for internal radiation treatment of PLC.

Adult↗
PubMed1993

Yttrium-90 glass microspheres injected via the portal vein. An experimental study.

Nondegradable glass microspheres (35 mu) were injected into the portal vein for toxicity test in 15 rabbits. In 10 animals the microspheres were loaded with 90Y, giving liver absorbed doses between 24.6 and 437.4 Gy, and in 5 with 89Y (control group). The total amount of microspheres injected in each animal varied between 35 and 140 mg. The rabbits in the experimental group tolerated the effect of radioembolization in a dose 4 times higher than the upper limit of the clinical dose (100 Gy). After injection of 90Y glass microspheres into the portal vein of rats with diethylnitrosamine (DEN)-induced hepatic carcinoma, the microspheres, in addition to the liver parenchyma, accumulated in central and peripheral parts of the cancer nodules, causing necrosis. The internal radiation therapy of 90Y glass microspheres delivered via the portal vein may be an effective nonsurgical method for the treatment of liver cancer, especially in small nodules.

Animals↗
PubMed1990

Studies on structures of some platinum complexes with 1,1-cyclopropanedicarboxylate.

The crystal structures of [Pt(NH3)2CPrDCA].H2O (I), [Pt(CH3NH2)2CPrDCA] (II), and [Pt(dmbn) CPrDCA].2.5H2O (III) (where CPrDCA is 1,1-cyclopropanedicarboxylate; dmbn is 2,3-dimethyl-2,3-butyldiamine) are determined. Compound I crystallizes in the orthorhombic space group Pnma with the cell dimensions: a = 6.517(2), b = 9.709(3), c = 14.205(5) A, Z = 4, R = 0.058. Compound II is monoclinic with space group P2(1)/n, a = 9.648(3), b = 8.720(2), c = 12.770(4) A, beta = 107.12(2), Z = 4, R = 0.059. Compound III belongs to the monoclinic system space group P2(1)/m with the cell dimensions: a = 6.494(1), b = 19.638(3), c = 6.606(1)A, beta = 94.44(1), Z = 2, R = 0.038. Electronic structures of the complexes are studied and the correlation between structure of the amine ligands and biological activity of the complexes is explored.

Antineoplastic Agents↗
PubMed1989

Activity of human placental gamma globulin in blocking immune functions in vitro and in abrogating the xenogeneic, local graft-versus-host reaction.

In order to understand the mechanism of immunosuppression caused by infusion of placental gamma globulin (PGG) in patients with renal allografts, rheumatoid arthritis, and graft-versus-host disease (GVHD) following bone marrow transplantation (BMT), we have examined the effect of PGG in vitro and in a model of the xenogeneic, local graft-versus-host reaction (LGVHR). PGG inhibited lymphocyte proliferation in mixed lymphocyte cultures (MLC) (P less than 0.005) and depressed interleukin-2 (IL-2) levels in such cultures at 72 hours (P less than 0.01). In contrast phytohemagglutinin (PHA)- and pokeweed mitogen (PWM)-induced T and B lymphocyte blastogenesis was not affected by such PGG treatment. PGG neither decreased the [3H] TdR pulse incorporation in unstimulated lymphocytes nor affected cell viability. Cell cycle analysis by flow cytometry showed that PGG reduced the percentage of cells in S and G2, M phases during the MLC, but did not alter cell cycling during PWM-stimulated proliferation. An immunosuppressive effect of PGG on the LGVHR was tested in a model of intracutaneous transplantation of PGG-treated human lymphocytes into cyclophosphamide-immunosuppressed rats. Lymphoprep-separated human tonsillar lymphocytes were incubated with RPMI-1640 buffer containing: (1)PGG, 4 mg/ml, (2) human plasma albumin, 4 mg/ml, (3) mitomycin-C, 25 micrograms/ml, or (4) no additive. Cells of each preparation (3 X 10(7) cells in 0.1 ml) were injected intracutaneously into cyclophosphamide-treated male rats at separate abdominal locations. A fifth site received only the buffer solution. Five days after injection of cells, each rat received [125I]UdR (10 muCi) intraperitoneally and was killed after 5 hours.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

[A fast determination of serum bilirubin with the interference from hemolysis and turbidity by three wavelength spectrophotometry].

In determination of bilirubin in serum by means of color reaction when hemolysis and turbidity are present, the reliability of the measurement is decreased by the interference from hemoglobin and other turbidities. Direct measurement of bilirubin in serum by three wavelength spectrophotometry at 500 nm, 450 nm and 370 nm instead of by color reaction, provides a fast, semi-micro and accurate way without the use of any reagents. Besides the rise of the baseline by blood cells and turbidities can be corrected without the consideration of hemolysis. Under the given experimental condition, the mean recovery is 96.3 +/- 2.41% (n = 6), coefficient of variation (CV) is 4.0%.

Bilirubin↗
PubMedDate not supplied

Experimental studies of portal venous embolization with iodized oil in rats with experimentally induced liver cancer.

PURPOSE: To assess the feasibility of portal venous embolization (PVE) with iodized oil in the treatment of human hepatocellular carcinoma (HCC), the distribution of iodized oil after PVE and tumor vascularity after hepatic arterial embolization (HAE) with iodized oil was determined in 25 rats with n-nitrosodiethylamine-induced liver cancer. MATERIALS AND METHODS: Under microscopic guidance, HAE with 1 mL of iodized oil was performed in 10 rats. After HAE, low-kilovoltage radiography in four rats and Microfil perfusion techniques in six were used to investigate the distribution of iodized oil and the portal blood supply, respectively. Low-kilovoltage radiography and histologic examination were performed to observe the distribution of iodized oil in 15 rats after PVE with doses of 0.6 mL/kg in each rat. RESULTS: After HAE with iodized oil, it was common that tumor nodules smaller than 5 mm in diameter were filled with Microfil perfused through the portal vein. After PVE, tumor nodules (< 5 mm) were completely filled with iodized oil, while filling defects were observed in larger tumor nodules (> 5 mm), which could have been filled through hepatic arterial perfusion. CONCLUSION: PVE with iodized oil may have a role in the treatment of hepatic malignant tumors, and it may play an important role in early detection and treatment of small tumor nodules (< 5 mm) supplied mainly by the portal vein.

Animals↗