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Biomedical subjects

Y Sun

Publications and source records attributed to Y Sun.

At least 433 records · Page 24Linked to original sources
PubMed1999

Regulation of adrenal scavenger receptor-BI expression by ACTH and cellular cholesterol pools.

Scavenger receptor BI (SR-BI) mediates selective uptake of high density lipoprotein (HDL) cholesteryl ester in the liver and adrenal gland. Adrenal SR-BI is increased both in adrenocorticotropic hormone (ACTH)-treated mice and also in apolipoprotein A-I knock-out (apoA-I0) mice which have depleted adrenal cholesterol stores. The goal of the present study was to determine whether adrenal cholesterol stores and ACTH have independent effects on SR-BI expression in adrenal gland. Adrenal SR-BI levels were 5-fold higher in apoA-I0 than wild-type mice when killed under low stress condition, and plasma ACTH levels were similar in both strains. After male apoA-I0 or wild-type mice were treated with dexamethasone to suppress ACTH release, adrenal SR-BI protein levels were decreased in both groups but remained 13-fold higher in apoA-I0 than in wild-type mice. By contrast, uncontrolled stress or supplemental ACTH treatment increased SR-BI levels but narrowed the difference in SR-BI expression between apoA-I0 and wild-type. Cholesterol depletion by beta-cyclodextrin in cultured Y1-BS1 adrenal cells also led to a rapid 2- to 3-fold increase in SR-BI mRNA and protein levels, in association with a significant depletion of cellular free cholesterol. These results indicate that depletion of adrenal cholesterol stores can act independently from ACTH to increase SR-BI expression, but in vivo this effect is diminished under high ACTH conditions. Both stimuli may increase selective uptake via increased SR-BI as a means of replenishing cholesterol stores for steroid hormone synthesis.

Adrenal Glands↗
PubMed1999

[Cloning and expression analyses of down-regulated cDNA C6-2A in human esophageal cancer].

OBJECTIVE: To clone genes associated with the genesis of human esophageal cancer. METHODS: Identifying missing or low expressing cDNAs in human esophageal cancer tissues by mRNA differential display and examining its mRNA expression in 4 human cancer cell lines, 9 fetal tissues and other matched esophageal cancer tissues by Northern blot, dot blot and RT-PCR. RESULTS: One cDNA fragment named C6-2A, was cloned and sequenced. There was no identical sequence with C6-2A in BLASTN database; but in querying Genbank EST, the authors found that C6-2A was identical with ne27b03.s1NCI-CGAP-C03 humans sapiens cDNA clone IMAGE:898541 3' and zv30g07.rl Soares ovary tumor NbHOT homo sapiens cDNA clone 755196. 6/6 esophageal cancer tissues in Northern blot and 7/8 in dot blot did not or slightly express C6-2A. RT-PCR analysis showed that C6-2A was expressed much lower in 17/20 esophageal cancer tissues than adjacent microscopically normal mucosa, highly expressed in fetal esophageal mucosa, skin, cerebrum, placenta; moderately expressed in fetal stomach and liver, but not detected in fetal heart, small intestine and kidney. CONCLUSION: The high frequency of deletion of decreased expression of C6-2A in esophageal cell lines and human esophageal cancer tissues suggested that C6-2A might be involved in the carcinogenesis of esophagus.

Cloning, Molecular↗
PubMed1999

Serum antibodies to human papillomavirus 16 proteins in women from Brazil with invasive cervical carcinoma.

Serum samples from 194 cases and 217 controls participating in a case-control study of invasive cervical cancer in Brazil were examined for antibodies to human papillomavirus (HPV) 16 virus-like particles (VLPs) by ELISA. The prevalence of antibody in cases and controls was 47.4 versus 24.4% (P < 0.001). The prevalence was higher in women who had HPV-16 DNA in the genital tract (54.2%) than in those with other HPVs (36.8%) or no HPVs (44.8%), but the differences were not statistically significant. Among cases and controls, HPV-16 VLP antibodies were associated with a greater number of lifetime sexual partners (chi2 for trend, P < 0.001). Among controls, age was inversely associated with HPV-16 VLP seroreactivity (chi2 for trend, P = 0.019). The sera were previously tested for antibodies to HPV-16 E6 and E7 oncoproteins; there was no correlation between antibody titers to HPV-16 E6 or E7 and VLPs. The HPV-16 serological assays were compared as screening tests for invasive cervical cancer. The sensitivity and specificity estimates were 47.4 and 75.6% for HPV-16 VLP serology, 63.4 and 89.9% for either HPV-16 E6 or E7 serology, and 53.6 and 93.6% for high titers of either HPV-16 E6 or E7 or VLP antibodies. The utility of HPV-16 VLP ELISA as a screening test for invasive cervical cancer is limited by a high seroprevalence in women with probable prior exposure to HVP 16 but without disease.

Adult↗
PubMed1999

B7-1 antigen expression in tumor cells from cancerous human tissues.

OBJECTIVE: To explore the expression of B7-1 antigen (Ag), the most important costimulatory molecule for T-lymphocyte activation, on tumor cells from cancerous human tissues. STUDY DESIGN: The study group consisted of 82 biopsies taken from a variety of cancerous human tissues. Ten normal cervical specimens, used as controls, were taken from uteri removed for leiomyomas or leiomyomatosis. B7-1 molecule expression was identified using monoclonal antibody (Ab) with CD80 and the SABC technique. RESULTS: In most cases (50/82), the tumor cells were totally or partially B7-1 Ag positive. The positive products were distributed mainly on the cell surface and, in some cases, also in the cytoplasm. Although in transitional cell carcinoma of the bladder, all tumor cells in all three cases stained strongly with CD80, in squamous cell carcinoma and adnocarcinoma, the B7-1 expression in cancer cells was detected in 3/56 and 15/23 cases, respectively. The intensity and distribution of B7-1 expression from case to case were heterogeneous: half the cases had relatively homogeneous and stronger B7-1 expression in cancer cells. Additionally, there were B7-1+ dendritic cells and lymphocytes scattered or densely infiltrating interstitial tissue. In some cases, the endothelia of small vessels were proved to be B7-1+. There was one esophageal cancer specimen containing normal-looking mucosa in which B7-1 molecule expression was also demonstrated in the squamous and glandular epithelia. CONCLUSION: Our findings demonstrate that the tumor cells in cancerous human tissues do not all fail to express B7-1. The mechanism of the failure of hosts to reject tumors can be attributed not only to the lack of costimulatory molecules in tumor cells but also to events after the Ag-presenting process.

Adenocarcinoma↗
PubMed1999

[The role of NO/ET and the effect of electroacupuncture on injuried gastric mucosa in rats].

The aim of the present work is to observe changes in endothelium-derived factors--nitric oxide (NO) and endothelin (ET), with special reference to the regulative role of electroacupuncture (EA) in injured gastric mucosa of rat by ethanol. It was found that gastric mucosal blood flow (GMBF), transmucosal potential difference (PD) and the content of NO in the serum all decreased (P < 0.01), while the content of ET in the plasma and the lesion index (LI) of gastric mucosa increased (P < 0.01). After administration of L-Arg and SNP, the content of NO and GMBF increased significantly (P < 0.01), whereas the content of ET and LI decreased (P < 0.01). These effects were enhanced by EA at ZuSanLi (ST-36) points, which, however, were inhibited by NO biosynthetic inhibitor--L-NNA. The latter effect could be reversed by concurrent administration of L-Arg. The above results suggest that NO plays a critical part in protecting gastric mucosa against injury, which is also responsible for the protective effect of EA on injury of gastric mucosa.

Animals↗
PubMed1999

[Effects of metallothionein (MT) on burned skin of rats].

OBJECTIVE: To elucidate the relationship between skin viability and lipid peroxidation after deep partial thickness burn injury. METHODS: Deep partial thickness burn was produced. Metallothionin (MT) in different concentrations (0.5 x 10(-6) mol/L, 1 x 10(-5) mol/L) was topically applied. Oxygen consumption, succinate dehydrogenase(SDH), Schiff's base contents and healing time of wound were determined in 24 Wistar rats. Specimens were harvested at 8, 24, and 48-hour postburn. RESULTS: Oxygen consumption and SDH value decreased and Schiff's base value increased after burn injury. With the application of MT, oxygen consumption and SDH value of burned skin were significantly higher compared with control group, and Schiff's base value was significantly lower (P < 0.05 or P < 0.01). The mean healing time of burned wound was two days less in two MT protection groups. CONCLUSION: MT may be beneficial in improving postburn skin viability by attenuating lipid peroxidation of burned tissue.

Animals↗
PubMed1999

Endovascular embolization of traumatic carotid cavernous fistulas.

OBJECTIVE: To analyze the effectiveness of endovascular embolization on treatment of traumatic carotid-cavernous fistula (TCCF). METHODS: From 1986 to 1997, 482 cases of traumatic carotid-cavernous fistula were treated by endovascular embolization in the Beijing Neurosurgical Institute. Several kinds of balloon-catheter were used for embolization. External carotid-cavernous fistulas and rare carotid-cavernous fistulas (CCF) with minute leakage were treated by cyanoacrylate or coils. Although artery approach was applied in most cases (477 cases), vein approach showed its own advantages in some special cases. RESULTS: We found a special "bileakage sign" indicating multileakage of TCCF, which was never mentioned before. All 482 cases were embolized successfully, and 405 cases maintained the patency of internal carotid artery (ICA). No treatment-related deaths occurred and the symptoms and signs of 462 cases were relieved after embolization. Emergency embolization was needed in some conditions such as serious epistaxis, delayed or repeated subdural hematoma, and rapid visual impairment. CONCLUSION: Endovascular embolization of TCCF is a safe and efficient method. Carefully selected operation time, operative approach, and materials are the essential factors to reach a best result.

Accidents, Traffic↗
PubMed1999

[Transesophageal intraluminal ultrasonography in diagnosis of esophageal benign and malignant tumor].

OBJECTIVE: To study the value of transesophageal echo probe (TEEP) in the management of the esophageal benign and malignant tumor. METHODS: 32 patients with esophageal carcinoma and 11 patients with esophageal submucosal tumor underwent surgery. Preoperative examinations included upper gastrointestinal series, endoscopy, and TEEP. Among these patients, preoperative CT scan was also done in 7 patients with esophageal carcinoma and 8 patients with esophageal submucosal tumor. All the resected specimens, including lymph nodes, were examined histopathologically, and the results of preoperative study of TEEP and CT were compared respectively with both the intraoperative macroscopic findings and the pathologic examination of the resected specimens. RESULTS: For T staging of 31 patients with esophageal carcinoma, TEEP was 81% (25/31) accurate versus 43% (3/7) for CT. The accuracy of TEEP for predicting N staging was 77% (34/44). For eleven patients with esophageal liomyoma, the preoperative diagnosis of TEEP was the same as the result of pathology, but the diagnostic accuracy of CT was only 50.0% (4/8). CONCLUSION: TEEP is a reliable method for the preoperative TN-staging of esophageal carcinoma and diagnosis of esophageal liomyoma. Moreover, it is more accurate than CT. In our experience, the procedure was safe and no complication occurred.

Aged↗
PubMed1999

[Glutamine dipeptide enriched enteral nutrition improving gut permeability in sever burns].

OBJECTIVE: To determine the effect of glutamine dipeptide on gut permeability in severe burns. METHODS: Twenty-four severe burn patients were randomly divided into two groups: control group and GLN group. All patients received enteral nutrition for 12 days after burn. Both groups were isocaloric and isonitrogen. GLN group patients were given nutrition solution enriched with glutamine dipeptide at a dosage at 0.5 g.kg-1.day-1 (equivalent to L-glutamine 0.3 mg.kg-1.day-1). On the day 1 and 12 after burn, the plasma amino acid was measured by a standard amino acid analyzer. On the day 1, 3, 6 and 12, the gut permeability was detected with Lactulose and Manitol assay by HPLC-PED, and then wound healing rate of burn area was determined on the day 30 and hospital stay was recorded. ANOVA was done for data analysis. RESULTS: The plasma GLN concentrations decreased in both groups on day 1, (control group: 361.3 +/- 70.8 microns/L, GLN group: 348.6 +/- 52.5 microns/L, P = 0.624, normal value: 659.5 +/- 35.0 microns/L), and the GLN group showed high plasma GLN concentration on day 12 (566.4 +/- 128.3 microns/L), with significant difference between control group (417.6 +/- 74.8 microns/L, P = 0.002). On day 1, L/M ratio value was the highest in both groups. On day 3, L/M ratio in the GLN group became lower than that of control group, and returned to normal on day 6 and maintained to day 12. There were significant differences of wound healing rate between the two groups and the length of hospital stay on day 30 (CONTROL GROUP: (81 +/- 7)%, GLN group: (89 +/- 7)%, 0.018) (CONTROL GROUP: 68 +/- 27 days, GLN group: 49 +/- 13 days, P = 0.049). CONCLUSION: The glutamine-dipeptide enriched enteral nutrition can improve the plasma GLN level after severe burn, decrease the gut permeability from early stage, ameliorate wound healing rate on day 30, and reduce hospital stay.

Adolescent↗
PubMed1999

[Sodium arsenite selectively inducing apoptosis of G2 + M phase NB4 cells].

OBJECTIVE: To explore the mechanism of sodium arsenite inducing apoptosis of NB4 cells. METHODS: The apoptosis of NB4 cells was studied by flow cytometry, DNA gel electrophoresis and Western blot analysis. RESULTS: 1. Sodium arsenite induced apoptosis of NB4 cells while the cells were arrested in G2 + M phase; 2. dUTP-FITC specifically labeled NB4 cells in G2 + M phase after the cells were treated with sodium arsenite; 3. After the treatment the expressions of cyclin A, E, D1, D2 and D3 of the NB4 cells did not change significantly, while the expression of cyclin B1 was up-regulated with prolongation of the treatment; 4. Some of S phase NB4 cells expressed high level cyclin B1 during the early period of treatment (16 h), but most of NB4 cells expressing high level of cyclin B1 were in G2 + M phase. CONCLUSION: Sodium arsenite selectively induced apoptosis of G2 + M phase NB4 cells, accompanied by upregulation of cyclin B1.

Apoptosis↗
PubMed1999

[Correction of the secondary nasal deformities of the unilateral cleft lip and palate].

OBJECTIVE: To develop a new method to correct secondary nasanl deformities of cleft lip and palate. METHODS: Establishing the balance of maxilla on both sides, followed by varied procedures to correct anormaly of osseous-cartilagious framework of nose, and taking some of nasal-labial muscle to restore the continuity and balance of anterior facial expressive muscles. RESULTS: 78 cases were treated by this way and the result was satisfying. CONCLUSIONS: Imbalance of maxilla and anterior facial expressive muscle and anormaly of nasal framework should be repaired for correcting the nasal deformity of cleft lip and palate effectively.

Adolescent↗
PubMed1999

[Mitomycin, vindesine and cisplatin combination therapy in the treatment of advanced non-small cell lung cancer: a report of 108 cases].

OBJECTIVE: To evaluate the results of combination chemotherapy with mitomycin (MMC), vindesine (VDS) and cisplatin (DDP) in patients with advanced non-small cell lung cancer (NSCLC). METHODS: A total of 108 patients with advanced NSCLC was enrolled in this study. Adenocarcinoma (74 cases) and squamous-cell carcinoma (23 cases) were the most common type of malignancy. Thirty patients received prior chemotherapy while 78 did not. RESULTS: Complete response was observed in 1 patient and partial response in 36 patients with an overall response rate (RR) of 34.3%. The RR was significantly higher in the previously untreated patients (41.0%) and than that in the pretreated patients (P = 0.0169). The RR did not significantly differ between patients with squamous--cell carcinoma (30.4%) and adenocarcinoma (32.4%). That of patients with metastases to the lymph nodes, to the other parts of lung, liver and bone was 43.1%, 32.4%, 25.0% and 0, respectively. The median response duration was 3 months and the median survival period was 7 months. The dose limiting toxicity was neutropenia, which was in grade III and IV in 41.7% of the treated patients. Grade III and IV thrombocytopenia was observed in 6.5% and grade III and IV nausea and vomiting in 21.3% of the treated patients. CONCLUSION: A higher response rate is attainable in patients with advanced NSCLC treated by MMC, VDS and DDP with tolerable toxicity.

Adult↗
PubMed1999

[Alterations of FHIT gene and p16 gene in lung cancer and metastatic hilar lymph nodes].

OBJECTIVE: To investigate alterations of fragile histidine triad (FHIT) gene and p16 gene in lung cancer. METHODS: Forty-nine lung cancer specimens and 16 matched metastatic hilar lymph nodes of lung cancer patients were examined for abnormalities of p16 and FHIT genes by using RT-PCR and RT-PCR-SSCP. RESULTS: Thirty-two of 47(68.1%) samples of primary lung cancer and 15 of 16 (93.8%) samples of metastatic hilar lymph nodes exhibited loss of FHIT gene transcripts. In 14 of the 47 samples of primary lung cancer(29.8%), and 9 of 16 samples of metastatic hilar lymph nodes(56.3%), FHIT gene transcripts were deleted in exones 1-4. The deletion rate of p16 gene transcripts in exons 2-3 was 36.7% (18/49) in primary and 56.3% (9/16) in metastatic lymph nodes, respectively. The loss of p16 or FHIT expression did not correlate with sex, smoking, TNM stage, but was more frequently observed in poorly differentiated cancer. No mutation of FHIT and p16 cDNA was found by SSCP. CONCLUSIONS: Loss of FHIT and p16 gene transcript is frequent in lung cancer and may be an early event in lung carcinogenesis. Mutations may not be the major mechanisms of p16 and FHIT gene inactivation. Lung cancer with FHIT and p16 gene alterations have more malignant phenotype and behavior.

Acid Anhydride Hydrolases↗
PubMed1999

[Studies on the spectrum features of nasalized vowels].

OBJECTIVE: To study the spectrum features of nasalized vowels and set up effective indexes to reflect the features. METHODS: The acoustic features of 100 children's speech, aged 5 to 12 years old, consisted of 40 unrepaired cleft palate children, 28 VPI children and 32 normal children, were studied by the application of digital spectrograph. RESULTS: No significant changes in the frequency of inherent formants of each vowel, appearance of one relatively fixed extra formant in the low frequency area, and the energy of high frequency area being damped obviously were the main spectrum features of nasalized vowels. CONCLUSION: There are three main features on the spectrums of nasalized vowels compared to that of oral vowels. Nasal resonance index (NRI) can effectively distinguish the extra formant in low frequency area of oral vowel /a/ from nasalized vowel /a/. Energy damping index (EDI) can effectively reflect that the energy of high frequency area of each nasalized vowel is damped obviously.

Child↗
PubMed1999

[Experimental study on apoptosis induced by ursolic acid isolated from asparagus in HL-60 cells].

OBJECTIVE: To study the inhibitory effect of ursolic acid isolated from Asparagus on the proliferation of HL-60 cells. METHODS: Effects of ursolic acid on the growth and apoptosis were evaluated by MTT assay, DNA gel electrophoresis and morphology observation respectively. RESULTS: The IC50 value of ursolic acid for HL-60 cells was found to be 8.26 mumol/L and 10-50 mumol/L of ursolic acid could induce apoptosis of HL-60 cells expressed to ursolic acid for 1 day. CONCLUSION: Ursolic acid can markedly inhibit HL-60 cells as well as induction of cells apoptosis.

Antineoplastic Agents, Phytogenic↗