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Y Gao

Publications and source records attributed to Y Gao.

At least 217 records · Page 12Linked to original sources
PubMed1999

Sensitivity of an epstein-barr virus-positive tumor line, Daudi, to alpha interferon correlates with expression of a GC-rich viral transcript.

The exquisite sensitivity of the Burkitt's lymphoma (BL)-derived cell line Daudi to type I interferons has not previously been explained. Here we show that expression of an Epstein-Barr virus (EBV) transcript, designated D-HIT (Y. Gao et al., J. Virol. 71:84-94, 1997), correlates with the sensitivity of different Daudi cell isolates (or that of other EBV-carrying cells, where known) to alpha interferon (IFN-alpha). D-HIT, transcribed from a GC-rich repetitive region (IR4) of the viral genome, is highly structured, responding to RNase digestion in a manner akin to double-stranded RNA. Comparing EBV-carrying BL cell lines with differing responses to IFN-alpha, we found the protein levels of the dsRNA-activated kinase, PKR, to be similar, whereas the levels of the autophosphorylated active form of PKR varied in a manner that correlated with endogenous levels of D-HIT expression. In a classical in vitro kinase assay, addition of either poly(I)-poly(C) or an in vitro-transcribed D-HIT homolog stimulated the autophosphorylation activity of PKR from IFN-alpha-treated cells in both EBV-positive and EBV-negative B lymphocytes. By transfection experiments, these RNAs were shown to reduce cell proliferation and to sensitize otherwise relatively insensitive Raji cells to IFN-alpha. The data lead to a model wherein the D-HIT viral RNA also serves as a possible transcriptional activator of IFN-alpha or cellular genes regulated by this cytokine.

B-Lymphocytes↗
PubMed1999

Role of protein kinase G in nitric oxide- and cGMP-induced relaxation of newborn ovine pulmonary veins.

In a variety of systemic blood vessels, protein kinase G (PKG) plays a critical role in mediating relaxation induced by agents that elevate cGMP, such as nitric oxide. The role of PKG in nitric oxide- and cGMP-induced relaxation is less certain in the pulmonary circulation. In the present study, we examined the effects of inhibitors of PKG on the responses of isolated fourth-generation pulmonary veins of newborn lambs (10 +/- 1 days of age) to nitric oxide and cGMP. In vessels preconstricted with endothelin-1, nitric oxide and 8-bromo-cGMP (a cell-membrane-permeable cGMP analog) induced concentration-dependent relaxation. The relaxation was significantly attenuated by beta-phenyl-1, N(2)-etheno-8-bromoguanosine-3',5'-cyclic monophosphorothionate (Rp-8-Br-PET-cGMPS; a PKG inhibitor) and N-[2-(methylamino)ethyl]5-isoquinolinesulfonamide [H-8; an inhibitor of PKG and protein kinase A (PKA)] but was not affected by KT-5720 (a PKA inhibitor). Biochemical study showed that PKG activity in newborn ovine pulmonary veins was inhibited by 8-Br-PET-cGMPS and H-8 but not by KT-5720. PKA activity was not affected by 8-Br-PET-cGMPS but was inhibited by H-8 and KT-5720. These results suggest that PKG is involved in relaxation of pulmonary veins of newborn lambs induced by nitric oxide and cGMP.

Animals↗
PubMed1999

Developmental change in magnesium sulfate-induced relaxation of rabbit pulmonary arteries.

Magnesium causes a variety of vascular smooth muscle to relax. The present study was designed to determine whether there is a developmental change in the magnesium-induced response of pulmonary vasculature. Isolated pulmonary arteries (PA) of newborn (1- to 3-day-old) and juvenile (4- to 6-wk-old) rabbits were suspended in organ chambers filled with modified Krebs-Ringer bicarbonate solution (95% O(2)-5% CO(2), 37.0 degrees C), and their isometric tension was recorded. In arteries preconstricted with endothelin-1 to a similar tension level, MgSO(4) caused greater relaxation of juvenile rabbit PA than that of the newborn rabbit PA. Verapamil, a voltage-dependent Ca(2+) channel blocker, attenuated magnesium-induced relaxation in juvenile rabbit PA but not in newborn PA. The uptake of Ca(2+) of juvenile rabbit PA was inhibited by MgSO(4), and the inhibition was attenuated by verapamil. The uptake of Ca(2+) of newborn rabbit PA was smaller than that of the juvenile PA and was not significantly affected by MgSO(4) and verapamil. These results demonstrate that there is a developmental increase in the dilator effect of MgSO(4) in rabbit PA. In newborn rabbit PA, an incomplete maturation of the voltage-dependent Ca(2+) channels may contribute to the smaller vasodilation induced by MgSO(4).

Animals↗
PubMed1999

Studies on the histogenesis of myxomatous tissue of human coronary lesions.

Myxomatous tissue is a characteristic component of human coronary artery lesions, found more often in restenotic lesions. It represents a bulky accumulation of stellate-shaped cells of unknown histogenesis that are embedded in a loose stroma. We analyzed 64 atherectomy specimens containing substantial amounts of myxomatous tissue by using immunohistochemistry, in situ hybridization, and electron microscopy techniques. Stellate cells represented a heterogeneous population, sharing features of smooth muscle cells (SMCs), macrophages, as well as antigen-presenting dendritic cells. Like quiescent medial SMCs, the stellate cells in all specimens expressed high levels of SM alpha-actin message and protein and showed heterogeneity with respect to heavy-chain myosin, SM22, desmin, and vimentin. Ultrastructurally, stellate cells resembled SMCs, with some peculiarities that distinguish them from both differentiated and dedifferentiated SMCs. In contrast to quiescent SMCs, the stellate cells expressed high levels of acidic fibroblast growth factor mRNA and protein similar to cells of monocyte/macrophage lineage. However, stellate cells did not express the marker of mature macrophages, HAM56, and were heterogeneous with respect to CD68. Moreover, unlike SMCs, the stellate cells bore some of the major phenotypic markers of dendritic cells: they were S100-positive and showed various reactivity with respect to CD1a and human leukocyte antigen (HLA)-DR. Invasion of myxomatous tissue with CD45RO-positive T lymphocytes was correlated with strong expression of CD1a in these specimens. Stellate cells also expressed a pericyte marker, high-molecular-weight melanoma-associated antigen. We conclude that stellate cells of myxomatous tissue represent a specific phenotype of mesenchymal cells (possibly pericytes), which is activated to express some markers of antigen-presenting cells. These findings suggest involvement of the stellate cells in a local immune response.

Actins↗
PubMed1999

Building dictionaries of 1D and 3D motifs by mining the Unaligned 1D sequences of 17 archaeal and bacterial genomes.

We have used the Teiresias algorithm to carry out unsupervised pattern discovery in a database containing the unaligned ORFs from the 17 publicly available complete archaeal and bacterial genomes and build a 1D dictionary of motifs. These motifs which we refer to as seqlets account for and cover 97.88% of this genomic input at the level of amino acid positions. Each of the seqlets in this 1D dictionary was located among the sequences in Release 38.0 of the Protein Data Bank and the structural fragments corresponding to each seqlet's instances were identified and aligned in three dimensions: those of the seqlets that resulted in RMSD errors below a pre-selected threshold of 2.5 Angstroms were entered in a 3D dictionary of structurally conserved seqlets. These two dictionaries can be thought of as cross-indices that facilitate the tackling of tasks such as automated functional annotation of genomic sequences, local homology identification, local structure characterization, comparative genomics, etc.

Algorithms↗
PubMed1999

[Investigation of the apoptosis and proliferation in endometriotic cells].

OBJECTIVE: To clarify whether apoptosis is involved in endometriosis and the effects of estradiol, progesterone and mifepristone on the expression of epidermal growth factor receptor(EGFR) in cultured human endometriotic cells. METHODS: Apoptosis index and bcl-2 gene expression were examined in cultured ectopic endometrial cells from women with endometriosis (n = 15 samples) and compared with eutopic endometrial cells from non-endometriosis cases(n = 11 samples). Apoptotic cells were detected by flowcytometry; bcl-2 gene expression demonstrated by in situ hybridization technique. The cultured endometriotic cells were stimulated by estradiol(E2, 10 nmol/L), progesterone(P, 100 nmol/L), and P + mifepristone(P 100 nmol/L + mifepristone 1,000 nmol/L) respectively for 5 days, the expression of EGFR mRNA of endometriotic cells were determined by reverse transcript polymerase chain reaction (RT-PCR) method. RESULTS: The apoptosis index was significantly decreased in the ectopic endometrial cells [(2.74 +/- 1.54)%] as compared to eutopic endometrial cells [(9.97 +/- 1.26)%] (P < 0.05). bcl-2 expression in endometriotic cells was significantly increased compared with the eutopic endometrial cells (P < 0.05). The expression of EGFR mRNA in E2, P group was 1.10 +/- 0.19 and 1.28 +/- 0.24 respectively, which were significantly higher than that of control(0.90 +/- 0.10, P < 0.01). In P + mifepristone group it was 0.63 +/- 0.11, significantly lower than that of control(P < 0.001). CONCLUSION: The resistance of endometriotic cells to apoptosis may be fundamental in the aetiology and (or) pathophysiology of endometriosis. Estradiol and progesterone promote hyperplasia and differentiation of endometriotic cells while mifepristone inhibits.

Adult↗
PubMed1999

[Determination of monocyte chemotactic protein-1 in cultured endometriotic cells].

OBJECTIVE: To investigate the clinical significance of monocyte chemotactic protein-1 (MCP-1) produced by endometriotic tissues. METHODS: Expressions of MCP-1 mRNA and MCP-1 protein were determined by dot blot analysis, immunohistochemical method [streptavidin biotin-peroxidase complex (SABC)] and enzyme linked immunosorbent assay (ELISA) methods in cultured endometriotic cells with median (controls) or with interleukin-1 beta(IL-1 beta) 2 ng/ml (IL-1 beta group), and tumor necrosis factor-alpha(TNF-alpha) 20 mg/ml(TNF-alpha group) respectively. The endometriotic tissues were sourced from 15 patients with endometriosis. Meanwhile, the MCP-1 protein content of cultured supernatent was also measured. RESULTS: After exposured to IL-1 beta or TNF-alpha, the expression of MCP-1 mRNA and MEP-1 protein in the endometriotic cells were significantly higher than that in the control group (P < 0.01, P < 0.05 respectively); so was the MCP-1 protein content of supernatent. CONCLUSIONS: IL-1 beta and TNF-alpha can up-regulate the expression of MCP-1 in endometriotic cells, which may be related to the development of endometriosis.

Adult↗
PubMed1999

Therapeutic efficacy of transcatheter arterial embolization of primary hepatocellular carcinoma: discrepancy in different histopathologic subtypes.

OBJECTIVE: To evaluate preliminarily the therapeutic efficacy of transcatheter arterial embolization (TAE) for different histopathologic subtypes of primary hepatocellular carcinoma (HCC). METHODS: A retrospective study of 226 patients with histopathologically diagnosed primary HCC was performed. The patients were treated with either single TAE, surgical resection of tumor alone, or TAE combined with surgical resection. Follow-up information was achieved in 157 of 226 patients. Comparative analyses of survival data and image findings were performed with correlation to histopathologic classification and different therapeutic methods, respectively. RESULTS: Eight histopathologic subtypes of primary HCC were found in this group, including HCC of trabecular pattern, pseudoglandular pattern, fibrolamellar HCC and sclerosing HCC, as well as HCC of clear cell, of small cell, poorly differentiated or undifferentiated HCC, and hormonally active HCC. The accumulated survival rate for these 157 patients was 74.52% of 1 year, 53.50% of 2 years, 31.85% and 14.01% of 3 and 5 years, respectively. Fibrolamellar HCC and clear cell HCC had relatively higher survival rate (25.00% and 33.22% of 5 years, respectively) than that of other subtypes, and the median survival time of the latter was 71 months. The mean survival time was 25.06 months (SE = 1.87) in single TAE group, 30.38 (SE = 2.05) months in surgical resection, and 72 months (SE = 6.90) in TAE combined with resection. CONCLUSIONS: Discrepancies do exist in therapeutic effect of different subtypes of HCC. In this study, clear cell HCC was more sensitive to TAE than other subtypes, and, in contrast, small cell HCC and poorly differentiated or undifferentiated HCC were of lower sensitivity to TAE.

Carcinoma, Hepatocellular↗
PubMed1999

The change of insulin-like growth factor-1 in diabetic patients with neuropathy.

OBJECTIVE: To evaluate the possible relationship between insulin-like growth factor-1 (IGF-1) and diabetic neuropathy (DNP). METHODS: Sixty-nine patients with Type 2 non-insulin-dependent diabetes (54 with peripheral neuropathy and 15 without neuropathy) were observed. Normal controls were 34 non-diabetic persons. Diabetic peripheral neuropathy diagnosis was carried out taking into account results of NS, ND, NC and AF. After an overnight fast, blood was taken for IGF-1, glucose, hemoglobin Alc, C-peptide, and insulin. Plasma IGF-1 was measured by radioimmunoassay (RIA) method. RESULTS: The neuropathic group had significantly lower levels for IGF-1 (86.43 ng/ml +/- 45.18 ng/ml) compared to normal controls (119.68 ng/ml +/- 89.42 ng/ml) (P < 0.05), and to diabetic patients without neuropathy (113.75 ng/ml +/- 66.58 ng/ml) (P < 0.05). No significant difference was found between diabetic non-neuropathic group and normal control subjects (P < 0.05). In diabetic subjects there was a positive correlation (gamma = 0.27, P < 0.05) between IGF-1 and beat to variation in heart rate. There were negative correlation between IGF-1 and postprandial blood glucose (gamma = -0.3, P < 0.05), and aspartic acid translocase (gamma = -0.27, P < 0.05). CONCLUSION: In diabetic patients with peripheral neuropathy there are abnormalities of IGF-1 that may contribute to the pathogeneses of diabetic neuropathy.

Aged↗
PubMed1999

An analysis of factors influencing electrocardiogram stress test for detecting coronary heart disease.

OBJECTIVE: To evaluate factors influencing electrocardiogram (ECG) stress test. METHODS: The treadmill stress test and coronary angiogram (CAG) records were reviewed retrospectively in 435 consecutive patients with chest pain between 1991 and 1997. There were 44 cases with normal CAG but positive exercise stress test results (false-positive, Group A), and 33 cases with both negative CAG and negative exercise test (true-negative, Group B). The baseline ECG, echocardiogram, abnormal systolic blood pressure response and history of diabetes mellitus and hypertension in the two groups were compared. RESULTS: There was no significant difference between the two groups with respect to age, gender, and antianginal medication. More patients in Group A had hypertension (52.3% vs 27.3%, P < 0.05) and diabetes mellitus (15.9% vs 0%, P < 0.05). Left ventricular (LV) hypertrophy in baseline ECG and by echocardiogram was more often present in Group A (25.0% vs 3.0%, P < 0.05; 36.4% vs 12.1%, P < 0.05). There were no significant differences between the two groups with respect to maximal heart rate, maximal systolic blood pressure (BP), metabolic equivalents, postexercise systolic BP, termination for exercise test, baseline ECG with bundle branch block and ST depression. CONCLUSION: Our results suggest that LV hypertrophy and a history of hypertension or diabetes mellitus are the main factors influencing ECG stress test for detecting coronary heart disease.

Adult↗
PubMed1999

[A brief history of discovery of Helicobacter pylori].

The theoretical background for the diagnosis and treatment of upper digestive ulcer, gastritis and stomach carcinema was challenged by H. pylori, a microbe seems only under the microscope. This paper makes a brief review on the brief history of discovery and recent conclusion on the microbe, and explores its challenge to the traditional conception.

Digestive System Diseases↗
PubMed1999

[Application and comparison of meta and pooled analyses in the study of cancer epidemiology].

OBJECTIVE: To introduce two comprehensive methods of analysis, Meta and pooled, frequently used in cancer epidemiology, and to compare them with authentic examples. METHODS: From data of a multicenter case-control study of lung cancer risk factors among non-smoking females, "family history of lung cancer" and "smoking history of parents" were the two variables selected for analysis. Based on the data from individual centers, Meta and pooled methods were employed to perform comprehensive analysis and the results compared. In the former, both fixed and random effect models were considered. RESULTS: When the data from individual study centers were analyzed, odds ratios (OR) differed. The OR of variable "family history of lung history" was statistically significant in Shanghai, while that of variable "smoking history of parents" was statistically significant in Harbin. Given the fixed effect model, the results of analysis were identical under different conditions of analysis (non-adjusted, adjusted with Mantel-Haenszel methods and multivariate logistic analysis). The results were similar when random effect model was used. In case the fixed effect model was not valid and there were some differences obtained by the two methods, combined parameters calculated from random effect model would be used. Stratified logistic model seemed better than basic logistic model in the pooled analysis. CONCLUSION: The results from Meta and pooled comprehensive analyses are essentially consistent.

Female↗
PubMed1999

[Surgical treatment of esophageal leiomyosarcoma: a review of the literature and report of 11 cases].

OBJECTIVE: To discuss the clinical biocharacteristics, diagnosis, operation and prognosis of esophageal leiomyosarcoma (ELS). METHODS: Clinical materials and follow-up results of 11 surgically treated ELS patients were analyzed. RESULTS: All 11 cases received radical resection of tumor. The 5-year survival rate was 54.5% (6/11). Grossly, two types of ELS were observed: the polyp form (4 cases) and invasive form (7 cases). The 5-year survival rate was 75.0% and 42.9%, respectively. Two patients died of local recurrence, another 2 cases died of distant metastasis. CONCLUSION: In patients with ELS surgically treated, prognosis of polyp form ELS is better than that of invasive form ELS. Local recurrence and distant metastasis are the major cause of death.

Adult↗
PubMed1999

[Type IV collagen and C-erbB-2 expression in oral candidal leukoplakia].

OBJECTIVE: To investigate type IV collagen and C-erbB-2 expression in oral candidal leukoplakia. METHODS: 27 cases of oral candidal leukoplakia were studied by immunohistochemistry. RESULTS: In normal and simple hyperplastic epithelia type IV collagen was noted as brown linear staining along the basement membrane. The most obvious change in the staining pattern was that the linear staining became very thin or discontinued in dysplastic epithelia. C-erbB-2 was demonstrated in 25 cases(78%). The positive staining, as a reticular pattern, was located at cell membrane, and not correlated with epithelial dysplasia. CONCLUSION: The results indicate that type IV collagen expression changed in candidal leukoplakia with epithelial dysplasia. This kind of change may be related to basement membrane destruction. The immunohistochemically expression of C-erbB-2 has no correlation with epithelial dysplasia.

Candidiasis, Oral↗
PubMed1999

[Basal cell adenocarcinoma of the salivary gland: a clinicopathologic study of 14 cases].

OBJECTIVE: To study clinicopathologic features and behaviour of the basal cell adenocarcinoma of salivary gland tumor and prognosis of the patients, METHODS: 14 cases with basal cell adenocarcinoma were studied clinicopathologically. RESULTS: The clinical features were as follows: females more than males; most frequently in the minor salivary glands; 21.4% of cervical lymph node metastasis and 14.3% of distant metastasis; and rather poor prognosis. The histopathologic appearances were similar to those of basal cell adenoma, but with more mitotic figures and infiltrating growth. CONCLUSION: This tumor was of moderate grade malignancy. It must be treated radically. The elective neck dissection could be considered for the patients with extensive tumors.

Adenocarcinoma↗
PubMed1999

[Alteration of CD44v3 and CD44v6 expression in oral premalignant epithelia].

OBJECTIVE: To investigate the expression of CD44v3 and CD44v6 in oral premalignant epithelia and its relationship to the carcinogenesis of oral mucosa. METHODS: 85 normal, hyperplastic, dysplastic and malignant oral epithelia were studied by immunohistochemistry. RESULTS: Normal and hyperplastic epithelia showed strong CD44v3, v6 staining on cell membrane. Cells in the deep layers of moderate and severe dysplastic epithelia showed remarkably reduced staining intensity or no positive staining as compared with normal and hyperplastic epithelia. This down-regulation of CD44v3, v6 expression was noted in all 12 cases of severe dysplasia. In invasive front of squamous cell carcinoma and some metastases to lymphnode CD44v3 and v6 staining were also weak or negative. CONCLUSION: Low level expression of CD44v3 and v6 exists in moderate and severe epithelial dysplasia. This may be related to the reduction of cellular adhesion and thereby facilitates the infiltration of basement membrane by dysplastic cells.

Glycoproteins↗
PubMed1999

[Operative results of tethered cord syndrome].

OBJECTIVE: To evaluate the treatment results of 22 cases of spinal tethered cord syndrome (TCS) using microneurosurgical technique. METHODS: Form 1994 to 1997, 22 cases of TCS verified by MRI were treated. All patients'tips of conus were below L(2) vertebra shown by MRI. In this group, 4 cases had lipid disease in the sacral canal, 5 piloidal sinus, and 13 thick filum. The patients were operated on using linear incision. The incision included the terminal conus and the whole filum. Under the microscope, the adhesions of the caudal equine were separated and the filum was found out. The caudal equine was well combed. Lipoma and piloidal sinus were removed totally or partially. Loosening the spinal conus and repairing the dural matter prevented re-adhesion and re-tether. RESULTS: Follow-up (0.5 - 3 years) showed that all of the patients were recovered in different levels. CONCLUSIONS: TCS should be found as early as possible and treated under the microsurgical technique.

Adolescent↗