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Xiao-Dong Sun

Publications and source records attributed to Xiao-Dong Sun.

10 recordsLinked to original sources
PubMed2006

Effects of frozen storage on the structure of sarcocysts in pig muscle and implications in taxonomic studies.

UNLABELLED: The morphology of the cyst wall of Sarcocystis has unique characteristics that can be used in species identification. To find a suitable way to preserve Sarcocystis cyst samples for species identification, by light microscopy and electron microscopy, we recorded the morphological changes in the cysts of Sarcocystis suihominis and Sarcocystis miescheriana from pig muscle, induced by storage at -20 degrees C. Comparisons were made between fresh cysts and those subjected to frozen storage for periods of 3 days, 20 days and 30 days. RESULTS: cyst wall of the two Sarcocystis species appeared unaffected by storage. There was no obvious change in the length, nor in the width of the protrusions after storage (P>0.05), but the structure of the bradyzoite in the sarcocyst was in many cases disintegrated at -20 degrees C in 20 days for S. miescheriana and 30 days for S. suihominis. To our knowledge this is the first report that Sarcocystis cyst in muscle can be stored at -20 degrees C before and remain suitable for ultrastructural morphological study. Consequently, this paper proposes freezing as a convenient storage method for samples used in taxonomic studies of Sarcocystis.

Animals↗
PubMed2005

PVD following plasmin but not hyaluronidase: implications for combination pharmacologic vitreolysis therapy.

PURPOSE: To study whether intravitreal injection of plasmin + hyaluronidase safely induces posterior vitreous detachment (PVD). METHODS: Rabbits were randomized into three groups: (A) 20 rabbits, intravitreal injection of plasmin 1 U + hyaluronidase 20 U in balanced salt solution (BSS) 0.1 mL into one eye; (B) 12 rabbits, plasmin alone; (C) 12 rabbits, hyaluronidase alone. The fellow eye of each rabbit was injected BSS 0.1 mL. In Group A, scanning electron microscopy (SEM) was done in four rabbits at 0.5 hour and in four rabbits at 1 hour. After 7 days, all the remaining 36 rabbits received electroretinography, SEM was examined in eight of each group, and immunohistochemistry was done in four of each group. RESULTS: SEM disclosed the eyes of Group A had complete PVD (8/8), Group B partial PVD (7/8), and Group C (8/8) and all the control eyes (24/24) no PVD after 7 days. Partial PVD was found in 4/4 at 0.5 hour and complete PVD was seen in 3/4 at 1 hour in Group A. Immunohistochemistry showed that the amounts of laminin and fibronectin in the vitreoretinal interface were decreased in Group A and B versus the control eyes (P <0.001), but not in Group C versus the control eyes (P >0.05). Electroretinography showed no changes in any group (P >0.05). CONCLUSION: Vitreous injection of plasmin + hyaluronidase induced complete PVD with no obvious toxicity. Plasmin induced partial PVD, but hyaluronidase had no effects.

Animals↗
PubMed2004

Expression and significance of angiopoietin-2 in gastric cancer.

AIM: To investigate the expression and pathological factors of Angiopoietin-2 (Ang-2) in primary gastric cancers and adjacent normal tissues. METHODS: The expression of Angiopoietin-2 and VEGF were studied in 72 primary gastric cancers and adjacent normal tissues from the same patients by semi-quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) and immunohistochemistry. RESULTS: Ang-2 was mainly expression in tumor cells. There were significantly difference between expression of Ang-2 in primary gastric cancer and in adjacent normal tissue samples (P=0.003). It was statistically correlation between Ang-2 and VEGF expression in tumors (P=0.0055). With regard to Ang-2 expression in tumors, there were significant difference between early stage and advanced stage (P=0.017), and significant difference between positive vascular involvement and negative vascular involvement (P=0.032). However, there was no significant difference between moderate-poor differential type and high differential type (P=0.908), between positive lymph node metastasis and negative lymph node metastasis (P=0.752), between positive serosal invasion and negative serosal invasion (P=0.764). The cases with expression of Ang-2 were increasing with advanced stage and vascular involvement. CONCLUSION: The results manifested that Angiopoietin-2, coordinated with VEGF, play role in regulating tumor angiogenesis of gastric cancer.

Adult↗
PubMed2004

Expression and significance of VEGF-C and FLT-4 in gastric cancer.

AIM: To investigate the expression of pathological factors of VEGF-C and its receptor FLT-4 in primary gastric cancer and adjacent normal tissues. METHODS: The expression of VEGF-C and FLT-4 was studied in 80 primary gastric cancers and adjacent normal tissues from the same patients by semi-quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) and immumohistochemistry. RESULTS: Both primary gastric cancer and adjacent normal tissue could express VEGF-C and FLT-4, and FLT-4 expression was also detected in endothelial cells of stromal blood vessels and lymphatic vessels. There was a significant difference in expression of VEGF-C between primary tumor and adjacent normal tissue samples (P=0.01), and a statistical correlation between VEGF-C and FLT-4 expression in tumors (P=0.00886). With regard to VEGF-C expression, there was a significant difference between moderate-poor differential type and high differential type (P=0.032), and a significant difference between positive and negative lymph node metastases (P=0.024). However, there was no significant difference between positive and negative serosal invasions (P=0.219). CONCLUSION: VEGF-C and its receptor FLT-4 play a role in the development of gastric cancer, and the tumors with expression of VEGF-C and FLT-4 are more likely to have lymph node metastasis.

Adult↗
PubMed2004

[Construction of human MAGE-3 DNA vaccine and its immune effects observed in vivo].

To investigate the antitumor immune responses induced by MAGE-3 DNA vaccine, the recombinant mammalian expression plasmid pcDNA3.1/MAGE-3 was constructed by ligating MAGE-3 gene, which was amplified by RT-PCR, and the pcD-NA3.1 + vector. The recombinant plasmids were transfected into B16 cells by liposome, the expression of MAGE-3 was checked by RT-PCR, immunocytochemistry and Western blot. Then, 100 ug recombinant plasmids were injected intramuscularly per C57BL/6 mouse on 0, 10 and 20 days, with pcDNA3.1 + plasmid and PBS as controls. Splenocytes CTLs, the level of antibodies against MAGE-3 the changes of the T lymphocyte subsets and the levels of cytokines were checked after 3 times immunization. As a result, the mice immunized with pcDNA3.1/MAGE-3 plasmid can produce MAGE-3 specific immune response. The CTLs kill activities against B16/MAGE-3 cells was 51.08 +/- 7.41%, and had significant difference (P < 0.01) compared with that of pcDNA3.1 + group (8.44 +/- 1.89%) and PBS group (5.76 +/- 1.75%). The titre of antibody against MAGE-3 was 1:15, while controls were negtive. The number of CD4 + CD8 + and the levels of IFN-gamma IL-2 increased significantly after immunization with pcDNA3.1/MAGE-3 plasmid as compared with those of control groups (P < 0.01). It is concluded that the pcDNA3.1-MAGE-3 DNA vaccine are able to induce both cellular and humoral immune responses in vivo.

Animals↗
PubMed2003

A slowly formed transient conformer of Abeta(1-40) is toxic to inward channels of dissociated hippocampal and cortical neurons of rats.

The mechanism by which amyloid peptide (Abeta(1-40)) produces effects on neurotransmission is currently unresolved. In initial experiments, using the patch-clamp technique, we found that 11.5 microM of preaggregated Abeta(1-40) altered the hippocampal neuron resting membrane potential and inhibited action potential firing. To identify the toxic species, the effects of Abeta(1-40) on sodium (I(Na)), calcium (I(Ca)), and potassium (I(K)) currents in hippocampal neurons were examined as a function of peptide aggregation state in a specially designed miniature recording chamber. Aggregation reactions were induced by constant shaking, starting with 50 microM monomeric peptide. At 10- to 30-min intervals, the ionic currents were examined on a single neuron suspended in control saline and then in a 100-microl sample of the aggregating peptide. We found that samples of the peptide taken 60-120 min into the aggregation process contained species that exhibited maximal inhibitory effects over a broad potential range in the rank ordering of I(Na) > I(Ca). I(K) was inhibited only slightly at depolarized potentials. Inhibition of APF through blockade of these channels would inhibit normal neuronal activity and directly contribute to cognitive dysfunction. In previous studies on SH-EP cells, we showed that neither monomeric nor fibrillar peptide had significant effect on cell viability except during exposure to the 60-120 minute aggregation product when cell death was recorded. Our kinetic model demonstrated that the toxic species was a slowly formed transient conformer (activated monomer), which was the only aggregating species that passed through a maximum concentration during aggregation. This species amounted to only a small fraction of the total amount of aggregating peptide. We conclude that, for both the native neurons in the present study as well as SH-EP1 cells, the activated monomeric conformer of the peptide is the toxic species.

Alzheimer Disease↗
PubMed2003

Prospective study of scoring system in selective intraoperative cholangiography during laparoscopic cholecystectomy.

AIM: To evaluate of scoring system in predicting choledocholithiasis in selective intraoperative cholangiography (IOC) during laparoscopic cholecystectomy (LC). METHODS: The scoring system of predicting choledocholithiasis was developed during the retrospective study in 264 cases, and was tested in 184 to evaluate its predictive value in choledocholithiasis. RESULTS: The scoring system was developed in a retrospective study of 264 cases, the statistical analyses showed the predictive factors included sex, transaminase levels, alkaline phosphatase level, bilirubin level, and common bile duct diameter on ultrasonography. The scoring system was used in 184 cases prospectively, of which, 3 of 162 (1.9 %) cases scoring <3 had choledocholithiasis, 17 of 22 (77.3 %) cases scores >=3 had choledocholithiasis. A case of scores >=3 or more prospectively should be considered highly intraoperative cholangiography during laparoscopic cholecystectomy. CONCLUSION: The scoring system can predict choledocholithiasis and is helpful in selection patients for intraoperative cholangiography.

Cholangiography↗
PubMed2003

[Construction of MAGE-3 prokaryotic expression plasmid and its expression in Escherichia coli].

To express the GST-MAGE-3 protein in E. coli, and investigate the antitumor immune responses induced by Dendritic cells (DCs) pulsed with GST-MAGE-3 protein, the recombinant expression plasmid pGEX-MAGE-3 was constructed by ligating MAGE-3 gene, which was amplified by RT-PCR and confirmed by sequencing, and the pGEX-4T-2 vector. The recombinant plasmid was transformed into BL-21 E. coli. The expression of GST-MAGE-3 was induced with IPTG. The GST-MAGE-3 protein expressed as high as 32% of the total cellular protein. After purification with Glutathione Sepharose 4B, the purity of the protein was more than 90%, and 3mg GST-MAGE-3 was obtained from 100 mL BL-21 lysate. Dendritic cells from gastric carcinoma patients were pulsed with GST-MAGE-3 protein, and these DCs were used to stimulate the autologous T. lymphocytes. After 7 days, the T. lymphocytes cocultured with DCs pulsed with GST-MAGE-3 antigen exhibited specific cytotoxicity against MAGE-3 positive SGC-7901 cells. It is concluded that the GST-MAGE-3 protein are able to present antigen to T. lymphocytes, activate antigen-specific CTLs and induce special antitumor immune responses in vitro. Our results lay the groundwork for further research of the MAGE-3 vaccine.

Antigens, Neoplasm↗
PubMed2002

Adrenergic signalling between rat taste receptor cells.

In taste buds, synaptic transmission is traditionally thought to occur from taste receptor cells to the afferent nerve. This communication reports the novel observation that taste receptor cells respond to adrenergic stimulation. Noradrenaline application inhibited outward potassium currents in a dose-dependent manner. This inhibition was mimicked by the beta agonist isoproterenol and blocked by the beta antagonist propranolol. The alpha agonists clonidine and phenylephrine both inhibited the potassium currents and elevated intracellular calcium levels. Inwardly rectifying potassium currents were unaffected by adrenergic stimulation. Experiments using the RT-PCR technique demonstrate that lingual epithelium expresses multiple alpha (alpha1a, alpha1b, alpha1c, alpha1d, alpha2a, alpha2b, alpha2c) and beta (beta1, beta2) subtypes of adrenergic receptors, and immunocytochemistry localized noradrenaline to a subset of taste receptor cells. Collectively, these data imply strongly that adrenergic transmission within the taste bud may play a paracrine role in taste physiology.

Adrenergic alpha-Agonists↗