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W Shen

Publications and source records attributed to W Shen.

At least 109 records · Page 6Linked to original sources
PubMed1999

A seven-transmembrane, G protein-coupled receptor, FPRL1, mediates the chemotactic activity of serum amyloid A for human phagocytic cells.

We have previously reported (Badolato, R., J.M. Wang, W.J. Murphy, A. R. Lloyd, D.F. Michiel, L.L. Bausserman, D.J. Kelvin, and J.J. Oppenheim. 1994. J. Exp. Med. 180:203; Xu, L., R. Badolato, W.J. Murphy, D.L. Longo, M. Anver, S. Hale, J.J. Oppenheim, and J.M. Wang. 1995. J. Immunol. 155:1184.) that the acute phase protein serum amyloid A (SAA) is a potent chemoattractant for human leukocytes in vitro and mouse phagocytes in vivo. To identify the signaling mechanisms, we evaluated patterns of cross-desensitization between SAA and other leukocyte chemoattractants. We found that the chemotactic bacterial peptide, N-formyl- methionyl-leucyl-phenylalanine (fMLP), was able to specifically attenuate Ca2+ mobilization in human phagocytes induced by SAA, but only at very high concentrations, suggesting that SAA uses a low affinity fMLP receptor. Here we demonstrate that SAA selectively induced Ca2+ mobilization and migration of HEK cells expressing FPRL1, a human seven-transmembrane domain phagocyte receptor with low affinity for fMLP, and high affinity for lipoxin A4. Furthermore, radiolabeled SAA specifically bound to human phagocytes and FPRL1-transfected 293 cells. In contrast, SAA was not a ligand or agonist for FPR, the high affinity fMLP receptor. Thus, SAA is the first chemotactic ligand identified for FPRL1. Our results suggest that FPRL1 mediates phagocyte migration in response to SAA.

Amino Acid Sequence↗
PubMed1999

Mouse Dach, a homologue of Drosophila dachshund, is expressed in the developing retina, brain and limbs.

The Drosophila genes eyeless, eyes absent, sine oculis, and dachshund cooperate as key regulators of retinal cell-fate determination. Homologues of eyeless (Pax6), eyes absent (Eya1-2), and sine oculis (Six3) have been identified and are expressed in the developing vertebrate eye. We have cloned and characterized the structure and expression of mouse Dach, a homologue of Drosophila dachshund. Sequence analysis reveals the presence of two motifs, DD1 and DD2, which may be involved in the function of Dach/Dachshund as gene regulatory factors. In addition, DD1 shares sequence similarity to N-terminal sequences of Ski and SnoN, which are involved in cellular transformation and differentiation. Mouse and human Dach/DACH were localized to chromosome 14E1 and 13q21.3-22, respectively, by fluorescence in situ hybridization. Finally, in situ hybridization analysis demonstrated that Dach is expressed in similar tissues to those observed in Drosophila, including the embryonic nervous system, sensory organs, and limbs. The finding of Dach expression in the eye completes the list of vertebrate homologues of eyeless, eyes absent, sine oculis, and dachshund which as a group may function to control cell-fate determination in the vertebrate eye.

Amino Acid Sequence↗
PubMed1999

Family history characteristics, tumor microsatellite instability and germline MSH2 and MLH1 mutations in hereditary colorectal cancer.

Recent characterization of the molecular genetic basis of hereditary nonpolyposis colorectal cancer provides an important opportunity for identification of individuals and their families with germline mutations in mismatch repair genes. Cancer family history criteria that accurately define hereditary colorectal cancer are necessary for cost-effective testing for germline mutations in mismatch repair genes. The present report describes the results of analysis of 33 colorectal cancer cases/families that satisfy our modified family history criteria (Mount Sinai criteria) for colorectal cancer. Fourteen of these families met the more stringent Amsterdam criteria. Germline MSH2 and MLH1 mutations were identified by the reverse transcription-polymerase chain reaction and the protein truncation test, and confirmed by sequencing. Microsatellite instability analysis was performed on available tumors from affected patients. MSH2 or MLH1 mutations were detected in 8 of 14 Amsterdam criteria families and in 5 of the remaining 19 cases/families that only satisfied the Mount Sinai criteria. Three of the latter families had features of the Muir-Torre syndrome. A high level of microsatellite instability (MSI-H) was detected in almost all (16/18) colorectal cancers from individuals with MSH2 and MLH1 mutations, and infrequently (1/21) in colorectal cancer specimens from cases without detectable mutations. Families with germline MSH2 and MLH1 mutations tended to have individuals affected at younger ages and with multiple tumors. The Amsterdam criteria are useful, but not sufficient, for detecting hereditary colorectal cancer families with germline MSH2 and MLH1 mutations, since a proportion of cases and families with mutations in mismatch repair genes will be missed. Further development of cancer family history criteria are needed, using unbiased prospectively collected cases, to define more accurately those who will benefit from MSH2 and MLH1 mutation analysis.

Adaptor Proteins, Signal Transducing↗
PubMed1999

Pregnenolone sulfate and dehydroepiandrosterone sulfate inhibit GABA-gated chloride currents in Xenopus oocytes expressing picrotoxin-insensitive GABA(A) receptors.

We examined the effects of picrotoxinin, pregnenolone sulfate (PS) and dehydroepiandrosterone sulfate (DHEAS) on gamma-aminobutyric acid (GABA) responses in Xenopus oocytes injected with wild type alpha1, beta2 and gamma2 GABA(A) receptor subunits and in oocytes injected with wild type alpha1 and beta2 subunits and a mutated gamma2 subunit that eliminates picrotoxin sensitivity. All three agents inhibited GABA currents in oocytes injected with wild type subunits. Oocytes injected with the mutated gamma2 subunit showed no inhibition of GABA responses by picrotoxinin at concentrations up to 100 microM. PS and DHEAS inhibited GABA currents at similar concentrations in both sets of oocytes. These results indicate that PS and DHEAS do not require a functional picrotoxin site for inhibition of GABA responses.

Animals↗
PubMed1999

Oligonucleotide-based inhibition of embryonic gene expression.

We describe a technique to define gene function using antisense oligonucleotide (AS-ODN) inhibition of gene expression in mice. A single intravenous injection of an AS-ODN targeting vascular endothelial growth factor (VEGF) into pregnant mice between E7.5-8.5 resulted in a lack of primary angiogenesis. This enabled us to define the critical window required to inhibit VEGF expression and recapitulate the primary loss of function phenotype observed in VEGF (-/-) embryos. This phenotype was sequence-specific and time- and dose-dependent. Injection of an AS-ODN targeting a second gene, E-cadherin, into pregnant mice at E10 confirmed a hypothesized secondary phenotype. This is the first report of AS-ODN inhibition of gene expression in utero and provides a new strategy for target validation in functional genomics.

Animals↗
PubMed1999

Regulation of vascular endothelial growth factor-dependent retinal neovascularization by insulin-like growth factor-1 receptor.

Although insulin-like growth factor 1 (IGF-1) has been associated with retinopathy, proof of a direct relationship has been lacking. Here we show that an IGF-1 receptor antagonist suppresses retinal neovascularization in vivo, and infer that interactions between IGF-1 and the IGF-1 receptor are necessary for induction of maximal neovascularization by vascular endothelial growth factor (VEGF). IGF-1 receptor regulation of VEGF action is mediated at least in part through control of VEGF activation of p44/42 mitogen-activated protein kinase, establishing a hierarchical relationship between IGF-1 and VEGF receptors. These findings establish an essential role for IGF-1 in angiogenesis and demonstrate a new target for control of retinopathy. They also explain why diabetic retinopathy initially increases with the onset of insulin treatment. IGF-1 levels, low in untreated diabetes, rise with insulin therapy, permitting VEGF-induced retinopathy.

Animals↗
PubMed1999

Value of stimulated serum thyroglobulin levels for detecting persistent or recurrent differentiated thyroid cancer in high- and low-risk patients.

BACKGROUND: Serum thyroglobulin determination has been reported to be a sensitive indicator of persistent or recurrent differentiated thyroid cancer of follicular cell origin (DTC) after total thyroidectomy. The purpose of this investigation was to determine the accuracy of serum thyroglobulin levels in predicting persistent or recurrent DTC in euthyroid and hypothyroid patients. METHODS: One hundred ninety consecutive patients with DTC of follicular cell origin who had 4 or more thyroglobulin levels measured after total thyroidectomy were retrospectively evaluated. One hundred fifteen patients had serum thyroglobulin levels measured when hypothyroid for radioiodine scanning or ablation. Serum thyroglobulin levels were determined by commercial assays. One hundred twenty-two patients less than 45 years old were considered at low risk, whereas 68 patients more than or equal to 45 years old were considered at high risk on the basis of TNM classification. The mean follow-up period was 62 months. RESULTS: After thyroidectomy with or without central or modified radical neck dissection 120 patients had normal thyroglobulin levels (< or = 3 ng/mL) while receiving thyroid hormone. One hundred thirteen of the 120 patients (94%) with normal serum thyroglobulin levels had no evidence of recurrent tumor, whereas 6% (7 patients) had persistent or recurrent disease. Among 76 patients with persistent (28 patients) or recurrent (48 patients) disease, 70 had a serum thyroglobulin level > 3 ng/mL while receiving thyroid hormone. Overall, 14 of 115 patients, including 2 of 61 (3%) in the high-risk group and 12 of 54 (22%) in the low-risk group, only had elevated serum thyroglobulin levels when hypothyroid with high serum thyroid-stimulating hormone (TSH) levels documenting persistent or recurrent disease. In 1 patient the serum thyroglobulin level (240 ng/mL) was falsely elevated probably as a result of interfering antibodies because no tumor was identified surgically or pathologically, and the thyroglobulin concentration was < 3 ng/mL when analyzed in 3 other laboratories. CONCLUSION: Serum thyroglobulin testing is sensitive (91%) and specific (99%) for identifying patients with persistent or recurrent differentiated thyroid cancer. Serum thyroglobulin levels are most precise when patients are hypothyroid (high TSH) and may be unreliable in patients with antithyroglobulin antibodies. We recommend TSH-stimulated thyroglobulin testing for all patients after total thyroidectomy for differentiated thyroid cancer of follicular cell origin regardless of patient age or risk group.

Adult↗
PubMed1999

Development and validation of the Diabetes Quality of Life Clinical Trial Questionnaire.

OBJECTIVE: The objective of this study was to develop a valid and reliable health-related quality of life (HRQOL) questionnaire for use in multinational clinical trials of patients with type I and type II diabetes. METHODS: Through patient focus groups and expert clinician panels in the United States (US) and France, relevant HRQOL domains for patients with type I and type II diabetes were identified. A draft questionnaire was developed by including validated, widely used generic and diabetes-specific domains and by developing original questions as required. A pilot study (n = 123) was conducted to evaluate the psychometric properties of the draft questionnaire with revisions being subsequently made. Data collected from two multinational clinical trials of patients with type I and type II diabetes were used to further validate and enhance the questionnaire (DQLCTQ). RESULTS: A total of 942 patients were recruited in the clinical trials from Canada, France, Germany, and the United States. The mean age was 33.8 years for patients with type I diabetes (n = 468) and 58.2 years for patients with type II diabetes (n = 474). The mean HbAlc level at baseline was 8.6. The revised version of the questionnaire (DQLCTQ-R) contains a total of 57 questions comprising 8 generic and disease-specific domains, as follows: Physical Function; Energy/Fatigue; Health Distress; Mental Health; Satisfaction; Treatment Satisfaction; Treatment Flexibility; and Frequency of Symptoms. Intraclass correlation coefficients range from 0.74 to 0.90 and Cronbach's alphas range from 0.77 to 0.90. With very few exceptions, all eight domains were able to discriminate between type I and type II diabetes, tight and poor metabolic control, male and female, and good and poor self perceived control of diabetes. Four domains (Treatment Satisfaction, Health/Distress, Mental Health, and Satisfaction) were responsive to clinical change in metabolic control. CONCLUSION: The DQLCTQ-R is a reliable, valid, and comprehensive HRQOL instrument. It is suitable in multinational clinical trials to evaluate new or alternative treatments for patients with type I and type II diabetes.

Adult↗
PubMed1999

Internal calcium modulates apparent affinity of metabotropic GABA receptors.

The metabotropic GABA receptor (GABA(B)R) regulates calcium influx in neurons. Whole cell voltage-clamp techniques were employed to determine the effects of internal calcium on the activity of GABA(B)Rs. GABA(B)R receptor apparent affinity was maximal when bis-(o-aminophenoxy)-N,N,N',N'-tetraacetic acid (BAPTA) maintained internal calcium below 70 nM. Apparent affinity was reduced as internal calcium increased. EGTA did not produce similar effects, suggesting that localized increases in calcium influenced GABA(B)R apparent affinity. Confocal imaging disclosed relatively high internal calcium just below the plasma membrane of isolated neurons. BAPTA, but not EGTA, reduced this ring of high calcium. Heparin, dantrolene, and ryanodine increased GABA(B)R apparent affinity, effects similar to that of BAPTA. Calmodulin inhibitors also increased receptor apparent affinity. These results suggest that internally released calcium activates calmodulin, which reduces GABA(B)R apparent affinity. This identifies a reciprocal system in which the metabotropic GABA receptor can reduce calcium influx, but internal calcium can suppress this receptor pathway. Metabotropic glutamate receptors linked to inositol 1,4,5 trisphosphate (InsP(3)) raised internal calcium and suppressed the action of GABA(B)Rs. Thus negative feedback systems control the balance between excitatory and inhibitory metabotropic receptor pathways in retinal neurons.

Ambystoma↗
PubMed1999

Endometrial response to raloxifene compared with placebo, cyclical hormone replacement therapy, and unopposed estrogen in postmenopausal women.

OBJECTIVE: To determine the endometrial effects of raloxifene 60 mg/day in postmenopausal women as assessed by vaginal bleeding and endometrial thickness. DESIGN: Data from 1157 postmenopausal women were analyzed from a database consisting of four independent, double-blind, randomized, placebo-controlled trials (range = 6-30 months duration), a 24-month open-label randomized, cyclical hormone replacement therapy (HRT)-controlled trial, and a 6-month double-blind, randomized, unopposed estrogen-controlled trial. Vaginal bleeding rate was derived from self-reported adverse events collected at least every 6 months. Endometrial thickness was measured by ultrasonography at regular intervals. RESULTS: Raloxifene 60 mg/day was not significantly different from placebo with regard to the incidence of vaginal bleeding, the baseline-to-endpoint change in endometrial thickness, or the proportion of women experiencing an increase in endometrial thickness above baseline after either 12 or 24 months of therapy. Unexpected bleeding was reported significantly more frequently in the unopposed estrogen groups compared with the raloxifene group (raloxifene 60 mg/day, 0% versus estrogen, 50%; p = 0.002). A significantly greater baseline-to-endpoint increase in endometrial thickness was observed in both the HRT and estrogen groups compared with their respective raloxifene comparison group (raloxifene 60 mg/day, 0.01 +/- 2.0 mm versus HRT, 1.8 +/- 3.2; p < 0.001; raloxifene 60 mg/day, 1.1 +/- 1.7 mm versus estrogen, 7.8 +/- 3.8; p < 0.001). No cases of endometrial hyperplasia or cancer were diagnosed in the placebo or raloxifene 60 mg/day groups. Endometrial hyperplasia was diagnosed in one case in the HRT group and in two cases in the estrogen group. CONCLUSION: Raloxifene 60 mg/day for up to 30 months is not associated with vaginal bleeding or increased endometrial thickness in postmenopausal women.

Aged↗
PubMed1999

Cloning of Schistosoma japonicum Chinese strain 22.6kD membrane-associated protein (Sj-22.6) gene and its overproduction on Escherichia coli.

A 567bp DNA fragment was amplified from Schistosoma japonicum adult worm mRNA by RT-PCR. Sequence analysis revealed that this fragment contained S. Japonicum Chinese strain membrane-associated protein (Sj-22.6) gene. Then this gene was cloned into the expression vector pGEX-4T, and subsequently expressed in Escherichia coli. The recombinant GST-fusion protein was purified by glutathione agarose affinity chromatography. Its molecular weight was about 48 kD. The yield of expression was around 40 mg/L E.coli culture. The immunological test suggested that the recombinant protein had good antigenity which could make a good basis for the research of its immunological function in Schistosomiasis.

Animals↗
PubMed1999

[Expression of endothelial nitric oxide synthase mRNA in human placenta].

OBJECTIVE: To determine the localization and type of nitric oxide synthase in human placenta. METHODS: By polymerase chain reaction and in situ hybridization. The eNOS mRNA expression was observed in 10 cases of human normal term placenta and cord. RESULTS: In human normal term placenta, positive staining of eNOS was evident in the syncytiotrophoblast and the endothelium of umbilical artery and vein, positive staining also presented in the endothelium of stem villous vessels, but it was absent in the endothelium of terminal villous capillary. CONCLUSION: eNOS is present in syncytiotrophoblast and endothelium of stem villi vessels, and it can synthesize nitric oxide which results in the increase of nitric oxide in pregnancy.

Adult↗
PubMed1999

[Pregnancy induced hypertension complicated acute disseminated intravascular coagulation: clinical analysis of 26 cases].

OBJECTIVE: To determine the relationship between pregnancy induced hypertension (PIH) and acute disseminated intravascular coagulation (DIC). METHODS: 26 cases with PIH complicated acute DIC were analyzed retrospectively in five hospitals of Xi'an from 1980 to 1997. RESULTS: (1) In 26 patients with PIH complicated acute DIC, 7 cases died (26.92%), while 17 neonates died (58.62%) in 29 neonates (3 cases were twin pregnancy). Cesarean section and hysterectomy were performed on 7 cases respectively, including 4 cases underwent both of them. (2) The causative factors of PIH complicated acute DIC included placental abruption (7 cases), amniotic fluid embolism (4 cases), eclamptic seizure (4 cases), surgical injury (7 cases) and bleeding (4 cases). 7 cases induced by placental abruption were all cured, 4 cases induced by amniotic fluid embolism all died. CONCLUSION: There are close relationship between PIH and DIC, PIH complicated acute DIC is the major cause of maternal and perinatal mortality, special attention should be paid on preventing DIC for PIH.

Abruptio Placentae↗
PubMed1999

Interrelation between nitric oxide and endothelin-1 in an experimental acute hypoxia in rats and its intervention.

OBJECTIVES: To study the interrelation between nitric oxide (NO) and endothelin-1 (ET1) in experimental acute hypoxic rats, and to evaluate the mechanism of acute hypoxic pulmonary hypertension affected by NO and ET1 and its intervention. METHODS: Nicotinamide adenine dinucleotide phosphate (NADPH) diaphorase histochemical staining method, Griess biochemical assay and radioimmune assay were applied to investigate the changes of nitric oxide syntheses (NOS), NO and ET1 in normal, hypoxic, and L-Arginine (L-Arg) and dexamethasone treated hypoxic rats. RESULTS: In normal rats, the NOS stain was localized in pulmonary vascular endothelium, and in the hypoxic rats, the activity of NOS was significantly lower. The level of plasma NO was significantly lower during acute hypoxia, but L-Arg as well as dexamethasone could prevent the drop of plasma NO. The level of plasma ET1 rose up significantly in the acute hypoxic rats, but after L-Arg therapy, it was significantly reduced, however, dexamethasone could not affect plasma ET1. The level of plasma cyclic guanosine monophosphate (cGMP) was significantly lower in the acute hypoxic rats, and L-Arg could prevent the drop of plasma cGMP, but dexamethasone could not prevent the drop of plasma cGMP. CONCLUSIONS: NO and ET1 may modulate hypoxic pulmonary hypertension and acute hypoxia can result in acute hypoxic pulmonary hypertension. L-Arg can reverse the acute hypoxic pulmonary hypertension. Further study is needed if dexamethasone is beneficial in acute hypoxic diseases. NO may play an important role in physiology of the lung and acute hypoxic diseases.

Animals↗
PubMed1999

A comparative study on the effects of low dose of tPA and different regimens of intravenous urokinase in acute myocardial infarction.

OBJECTIVE: To compare the effects of low dose of recombinant tissue-type plasminogen activator (tPA) with those of conventional dose of urokinase (UK) and assess the influence of different regimens of intravenous UK in patients with acute myocardial infarction (AMI). METHODS: Eighty patients with AMI were randomized to 50 mg of tPA (Group I; n = 26) using an accelerating approach or 1.0-1.5 million U of UK (Group II; n = 54). UK was administered as a single bolus injection of whole dose (Group IIa; n = 26) or half dose bolus injection followed by half dose infusion (Group IIb; n = 28). All patients underwent coronary arteriography 90 min after the initiation of intravenous thrombolysis, and the infarct-related coronary artery (IRA) patency was evaluated. Cardiac events during hospitalization were recorded and predischarge left ventricular function was determined by two-dimensional echocardiography. RESULTS: The IRA patency rate was significantly higher in Group I (88.4%) than in Group II (53.7%) (P < 0.01). Group I patients had less cardiac events during hospitalization (11.5% vs 33.3%) and greater improvement in left ventricular function than Group II patients. However, these angiographic, left ventricular functional and prognostic parameters did not significantly differ between Group IIa and Group IIb. CONCLUSIONS: Thrombolysis after AMI with low dose of intravenous tPA exerts better angiographic and clinical effects than that with conventional dose of UK. The thrombolytic effects of UK were not affected by different regimens of intravenous administration of the agent.

Aged↗
PubMed1999

[Study on relationship between Deficiency Syndrome of TCM and the biological behavior in patients of esophageal carcinoma].

OBJECTIVE: To investigate the relation between Deficiency Syndrome (DS) of TCM and the invading depth, lymphnode metastasis, TNM stage and prognosis prediction of esophageal carcinoma. METHODS: According to Syndrome Differentiation of TCM, 101 patients of esophageal carcinoma were evaluated before operation and divided into two groups, the DS group and the non-DS group. RESULTS: Thirty-eight cases in the 101 patients were DS, among them, 14 were Qi-Deficiency, 10 Yin-Deficiency, 10 Qi-Yin Deficiency, 2 Qi- and blood Deficiency, 1 Yang-Deficiency and 1 Yin-Yang Deficiency. There were significant differences between the DS group and non-DS group in the invading depth (deeper in DS), metastasis of lymphnode (severer in DS) and TNM stage (later in DS) of esphageal carcinoma, (P < 0.05). CONCLUSION: There is a significant relation between DS and the biological behavior of esophageal carcinoma. The prognosis of DS patients is poorer than that of the non-DS patients.

Adenocarcinoma↗