Biomedical subjects

Shan Ding

Publications and source records attributed to Shan Ding.

10 recordsLinked to original sources

PubMed2006

Association of a distinctive strain of Epstein-Barr virus with gastric cancer.

Epstein-Barr virus (EBV) has been linked to gastric carcinoma (GC) with worldwide geographical variations attributable to types and variants of EBV. Here, we compare EBV strains between EBVaGC and healthy donors in Latin America, a high frequency area for EBVaGC. Tumor samples from 73 EBVaGC cases and throat washings from 329 healthy adults were examined for types 1 and 2 EBV and polymorphism at BamHI-F and BamHI-W1/I1 boundary regions and XhoI restriction site in LMP1 gene. Type 1 and prototype F of BamHI- F polymorphism accounted 59 (81%) and 69 (95%) of EBVaGC cases and 257 (78%) and 267 (81%) of healthy donors, respectively. Types I and "i" of BamHI W1/I1 polymorphism accounted 2 (3%) and 62 (85%) of EBVaGC and 85 (26%) and 170 (52%) of healthy donors, respectively (p<0.001). XhoI+ and - polymorphism accounted 60 (82%) and 4 (5%) of EBVaGC and 142 (43%) and 92 (28%) of healthy donors, respectively (p<0.001). Cosegregation analysis demonstrated that most of the 62 type "i" EBVaGC cases harbor XhoI+ strain (81%). However, among 143 type "i" healthy adults, both XhoI polymorphism were present in relatively similar frequencies (XhoI+ 58% and XhoI- 42%) (OR 9.0; 95% CI 1.2-69). Our findings are against to the proposed hypothesis that EBV strains are geographically but not disease-restricted. We conclude that most of the EBVaGC cases harbor a distinctive EBV strain (type "i"/XhoI +), but in healthy donors, this strain was as common as other strains. This finding is contrary to the proposed hypothesis that EBV strains are geographically but not disease-restricted and identified a healthy population group that share the same strain that predominate in EBVaGC cases.

Adult↗

PubMed2005

Epstein-Barr virus-associated gastric carcinoma: Evidence of age-dependence among a Mexican population.

AIM: To investigate features of Epstein-Barr virus (EBV)-associated gastric carcinoma (EBVaGC) among a Mexican population. METHODS: Cases of primary gastric adenocarcinoma were retrieved from the files of the Departments of Pathology at the Instituto Nacional de Cancerologia and the Instituto Nacional de la Nutricion in Mexico City. The anatomic site of the gastric neoplasia was identified, and carcinomas were histologically classified as intestinal and diffuse types and subclassified as proposed by the Japanese Research Society for Gastric Cancer. EBV-encoded small non-polyadenylated RNA-1 (EBER-1) in situ hybridization was conducted to determine the presence of EBV in neoplastic cells. RESULTS: We studied 330 consecutive, non-selected, primary gastric carcinomas. Among these, there were 173 male and 157 female patients (male/female ratio 1.1/1). EBER-1 was detected in 24 (7.3%) cases (male/female ratio: 1.2/1). The mean age for the entire group was 58.1 years (range: 20-88 years), whereas the mean age for patients harboring EBER-1-positive gastric carcinomas was 65.3 years (range: 50-84 years). Age and histological type showed statistically significant differences, when EBER-1-positive and -negative gastric carcinomas were compared. EBER-1 was detected in hyperplastic- and dysplastic-gastric mucosa surrounding two EBER-1-negative carcinomas, respectively. CONCLUSION: Among Latin-American countries, Mexico has the lowest frequency of EBVaGC. Indeed, the Mexican population >50 years of age was selectively affected. Ethnic variations are responsible for the epidemiologic behavior of EBVaGC among the worldwide population.

Adult↗

PubMed2005

[The application of the dissociate bone flap in treatment of the macrosis depressed skull fracture on the frontal orbit part].

OBJECTIVE: To study the reconstructive effect of the dissociate bone flap to repair the macrosis depressed skull fracture on the frontal and orbit part. METHODS: The coronal scalp flap was elevated and dissociate bone flap was expanding to the 2cm width beside the edge of depressed skull fracture. The first step was to extract the dissociate bone flap and make there is an area for operating . Then extract free bone fragments, and elevate the depressed orbital lamina and use the biological glue to stick it to its position. The free fragments extracted were stacked into a whole one and it to its position in use of the biological glue on the dissociate bone flap. The uneven inner table should was smoother with bon-wax. The prosthetic dissociate bone flap was put back on its position and fixation. RESULTS: From January 2000 to December 2004, 17 cases of the macrosis depressed skull fracture on the frontal and orbit part undertaken plastic surgery by the dissociate bone flap to treat the macrosis depressed skull fracture and obtained excellent curative effect. CONCLUSIONS: Using dissociate bone flap to treat the mocrosis depressed skull fracture on the frontal and orbit part can avoid the complication of the traditional operation, and make the method become a plastic surgical operation.

Adult↗

PubMed2003

Representation of cardinal contour overlaps less with representation of nearby angles in cat visual cortex.

Extensive attempts have been made to explain the neurobiological basis of the greater sensitivity of the visual system to vertically or horizontally oriented information than to information presented at oblique angles. However, investigators have largely ignored the overlap of the representation of a given angle with the representation of nearby angles. Recordings based on intrinsic optical signals were obtained in area 17 from 12 adult cats during the presentation of contours in various orientations. A method investigating both amplitude and statistical significance of changes was proposed to evaluate the orientation tuning properties for cell populations in the central area retinotopically corresponding to 0-15 degrees of visual field. Cardinal orientations were found to activate significantly greater areas in the exposed cortical area than the areas activated by oblique orientations. Areas activated by cardinal or oblique contours and those separated from them by 10 degrees were compared. A significantly lower degree of overlap was seen between areas activated by presentation of cardinal contours and areas activated by neighboring orientations compared with those for oblique orientations which overlapped more extensively with neighboring orientations. In addition, areas activated only by cardinal contours were significantly larger than areas activated only by oblique contours. These results demonstrated in cell population level that more cells prefer horizontal or vertical orientations, and these cells are tuned more sharply than oblique selective cells.

Animals↗

PubMed2003

Difference in the representation of cardinal and oblique contours in cat visual cortex.

Optical imaging based on intrinsic signals was used to analyze the structure of orientation column in area 18 of cat visual cortex. Recordings were obtained in 12 adult cats during presentation of contours in various orientations. In order to quantitatively evaluate the size of the response area, a method combining both information on the amplitude of the changes and the statistical significance of the changes was proposed. The results showed that the proportion of the cortical area activated reached a peak during the presentation of horizontal or vertical contours, whereas the areas activated by oblique contours were relatively smaller. Cardinal contours (0 degrees and 90 degrees ) activated 50.63 +/- 1.88% (mean +/- SE) of the cortical area in the recording site, whereas oblique contours (45 degrees and 135 degrees ) activated only 45.25 +/- 2.02% of the area. This difference in area was statistically significant (t = 2.38, d.f. = 11, and P < 0.05). The results demonstrated a difference in the representations of the cardinal and oblique contours in area 18 of the cat visual cortex.

Animals↗

PubMed2003

[Preparation and biological evaluation of PLA/chitosan composite materials].

Hypersusceptibility test, pyrogen test, cell cultivation, and toxicity examination were applied in the biological evaluation of the poly(lactic acid) (PLA)/chitosan composite materials. The results indicated that all the materials were negative, conforming to the ISO10993-1. The cell could grow well on the surface of the materials. So the PLA/chitosan composite materials have good biocompatibility and can be planted in the body as scaffolds.

Animals↗

PubMed2002

Glutamate-induced increases in intracellular Ca2+ in cultured rat neocortical neurons.

In neurons, changes in intracellular Ca2+ concentration ([Ca2+]i) trigger neurotransmitter release, regulate membrane excitability, affect gene expression, and govern short- and long-term forms of synaptic plasticity. Rises in cytoplasmic Ca2+ are thought to underlie the various effects of glutamatergic neurotransmitters within the central nervous system. In the present study, we applied a calcium imaging technique using a confocal laser scanning microscope to investigate the effects of excitatory amino acids on glutamate induced calcium influx in primary cultured neocortical neurons. Glutamate (5 microM) induced increases in [Ca2+]i in both the soma and dendritic processes of the cells. The increase was partially blocked by 10 microM DL-2-amino-5-phosphovaleric acid (APV), a NMDA antagonist. The reduction was higher in the dendritic process than in the cell body: the reduction was 58% in the cell body and 67% in the dendritic processes. In contrast, 5 microM 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX), a non-NMDA antagonist, had less effect on the response. We observed an 11% reduction in the dendritic processes, but no change in the cell bodies. The results demonstrated the heterogeneous distribution of APV- and CNQX-sensitive channels in primary cultured neocortical neurons. In both the cell body and dendritic processes, [Ca2+]i increase induced by low concentrations of glutamate was mainly due to the activation of NMDA receptors.

Animals↗

PubMed2002

Epstein-Barr virus-associated gastric carcinoma in southern India: A comparison with a large-scale Japanese series.

Epidemiological and clinicopathological features of Epstein-Barr virus (EBV) associated gastric carcinoma was compared in India and Japan, two countries differing markedly in gastric cancer incidence. Using in situ hybridization assay, the presence of EBV-encoded small RNA (EBER) was examined in 215, and 2,011 gastric cancer cases in Kerala, India, and Japan, respectively. Ten cases (5%), all males, in the Indian series were EBER-positive. This frequency was similar to that in the Japanese series (6.2%). As was the case with Japanese series, the EBV-associated gastric carcinoma in the Indian series was observed most frequently in the middle part of the stomach (1 in antrum, 4 in middle part, 2 in cardia, and 3 unknown), and, histologically, the diffuse type Lauren's classification (8 cases) was more common than the intestinal type (2 cases). Virus subtyping by PCR-RFLP revealed that all of the 10 EBV strains isolated from the EBER-positive Indian cases were subtype A, and wild-type F for Bam HI F region. In Bam HI I region, 8 cases were type C and the remaining 2 cases were type D. In either series, there was no significant difference in the frequency of tumors with p53 overexpression between EBER-positive and -negative cases. However, the proportion of cells with p53 overexpression in EBER-negative tumors was significantly higher than that in EBER-positive tumors regardless of histological type in both series. In conclusion, the frequency and major clinicopathological features of EBV-associated gastric carcinoma in south India were similar to those observed in Japanese series although gastric cancer incidence in these two countries differs markedly.

Adult↗

PubMed2002

[Novel scaffold materials for tissue engineering].

In this paper, the resorbable and degradable biomaterials often used in recent years are reviewed. These materials include natural and synthetical ones such as collagen, protein fiber, chitosan, polylactic acid (PLA), polyglycolic acid(PGA), polyanlydrides, etc.

Biocompatible Materials↗

PubMed2002

[Study on preparation and property of PLA/liquid crystal composite membranes].

In this paper we synthesised two kinds of hydrophilic liquid crystal, i.e. cholesteryl triethenyl glycol carbonate (TCC), cholesteryl tetraethenyl glycol carbonate (TeCC), which were blended with PLA with certain contents to form composite membranes. Contact angle test showed that the contact angle decreases with the increase of liquid crystal. The blood-compatibility of the composite membranes was assessed by blood clotting time and hemolysis ratio which showed that these PLA/liquid crystal composite membranes with the content of 30%-40% liquid crystal appeared to be beneficial in improving the blood compatibility and anticoagulation.

Biocompatible Materials↗