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Y Xie

Publications and source records attributed to Y Xie.

At least 289 records · Page 16Linked to original sources
PubMed1997

cAMP-dependent negative regulation of rat aldehyde dehydrogenase class 3 gene expression.

We investigated the inhibitory effects of intracellular cyclic adenosine monophosphate (cAMP) levels in regulating class 3 aldehyde dehydrogenase (aldh3) gene expression using cultures of primary rat hepatocytes and transient transfection experiments with HepG2 cells. In addition to regulation by an Ah receptor-dependent mechanism, expression of many members of the Ah gene battery have been shown to be negatively regulated. As was seen for the cytochrome P450 (cyp1A1) gene, aldh3 is transcriptionally inducible by polycyclic aromatic hydrocarbons (PAH), and this induction involving function of the arylhydrocarbon (Ah) receptor is inhibited by the protein kinase C (PKC) inhibitors, 1-(5-isoquinolinesulfonyl)-2-methylpiperazine di-HCl (H7) and staurosporine. However, PAH induction of ALDH-3 activity, protein, and mRNA was potentiated 2-4-fold by addition of the protein kinase A (PKA) inhibitors, N-(2-(methylamino)ethyl)-5-isoquinolinesulfonamide di-HCl (H8) and N-(2-guanidinoethyl)-5-isoquinolinesulfonamide HCl (HA1004). These PKA inhibitors had no effect on the PAH induction of the cyp1A1. Protein kinase A activity of cultured hepatocytes was specifically inhibited by H8 and HA1004 in a concentration-dependent manner, but not by H7, and there was an inverse correlation observed between potentiation of PAH-induced aldh3 gene expression and inhibition of specific PKA activity by the PKA inhibitors. The cAMP analog dibutyryl cAMP, the adenylate cyclase activator forskolin, and the protein phosphatase 1 and 2A inhibitor okadaic acid all dramatically inhibited both PAH induction and H8 potentiation of PAH induction of aldh3 expression but had no effect on induction of cyp1A1 expression in cultured hepatocytes. Both basal and PAH-dependent expression of a chloramphenicol acetyltransferase expression plasmid containing approximately 3.5 kilobase pairs of the 5'-flanking region of aldh3 (pALDH3.5CAT) were enhanced 3-4-fold by the PKA inhibitor H8 but not by the PKC inhibitor H7 (>20 microM). cAMP analogs, activators of PKA activity, or protein phosphatase inhibitors diminished expression of the reporter gene in a manner identical to the native gene in cultured rat hepatocytes. Using deletion analysis of the pALDH3.5CAT construct, we demonstrated the existence of a negative regulatory region in the 5'-flanking region between -1057 and -991 base pairs which appears to be responsible for the cAMP-dependent regulation of this gene under both basal and PAH-induced conditions. At least two apparently independent mechanisms which involve protein phosphorylation regulate aldh3 expression. One involves function of the Ah receptor which requires PKC protein phosphorylation to positively regulate both aldh3 and cyp1A1 gene expression and the other a cAMP-responsive process which allows PKA activity to negatively regulate expression of aldh3 under either basal or inducible conditions.

Aldehyde Dehydrogenase↗
PubMed1997

Human papillomavirus (HPV) in head and neck cancer. An association of HPV 16 with squamous cell carcinoma of Waldeyer's tonsillar ring.

BACKGROUND: Certain strains of human papillomavirus (HPV) have been shown to be etiologically related to the development of uterine cervical and other genital cancers, but their role in the development of malignancies at other sites is less well established. Previous studies have shown HPV DNA in tumors of the head and neck, but its prevalence has varied depending on the detection methods and the types of tumor and/or tissue examined. This study was undertaken to estimate the frequency of HPV DNA in squamous cell carcinoma (SCC) at different sites of the esophagus, head and neck and to compare the clinical behavior of HPV positive and negative tumors. METHODS: DNA was extracted from frozen tissue of 167 SCCs of the esophagus, head and neck. The DNA was screened for HPV sequences by polymerase chain reaction with two sets of consensus primers, one to a conserved region in the L1 gene (MY09/ MY11) and the other to a conserved region in the E1 open reading frame (IU/IWDO). The products were run on agarose gels, detected by ethidium bromide staining, and then the gels were subjected to Southern blot analysis and hybridized with probes specific to HPV 6, 16, and 18. All tumors found to be HPV positive with the consensus primers were amplified with type specific primers, and in selected cases the presence of HPV DNA was confirmed by restriction enzyme digestion of the tumor DNA with conventional Southern blot analysis. RESULTS: Overall, HPV sequences were found in 25 of 167 tumors (15%), but HPV was detected most frequently in tumors in Waldeyer's tonsillar ring. In that area, 9 of 15 (60%) were HPV positive. No HPV DNA was detected in 11 esophageal SCCs, 7 tumors of the pharynx/hypopharynx, or 6 pyriform sinus carcinomas. HPV DNA was detected in the following tumor sites: 1 of 28 (3.6%) in the larynx, 1 of 10 (10%) in the oral cavity, 5 of 39 (12.8%) in the tongue, 2 of 15 (13.5%) in the floor of the mouth, 3 of 21 (14.3%) supraglottic, and 1 of 7 (14.3%) in the lip. A high incidence of HPV DNA was also found in metastatic tumors located in cervical lymph nodes for which no primary site was clinically identified (3 of 8, 37.5%). With respect to age, gender, and tobacco and alcohol consumption, analysis of clinical data obtained by retrospective review showed no difference between patients with HPV DNA in their tumors and those in which no HPV was detected. However, HPV positive patients had larger tumors (P = 0.09) and a higher incidence of lymph node metastasis (P = 0.003). In spite of the higher stage of disease at presentation in HPV positive patients, there was no significant difference in 3-year survival rates between HPV positive patients and HPV negative patients (43.1% vs. 48.8%, respectively). Median follow-up was 27 months. CONCLUSIONS: In the head and neck, HPV-associated SCC had site specificity with the viral DNA frequently found in tumors in Waldeyer's tonsillar ring. Patients with HPV positive tumors presented with a higher stage of disease than patients with HPV negative tumors, but there was no significant difference in the 3-year survival rates between these two groups of patients.

Carcinoma, Squamous Cell↗
PubMed1997

Identification of a positive regulatory element responsible for tissue-specific expression of prostate-specific antigen.

The prostate-specific antigen (PSA) promoter (PSA-P) has been identified, characterized, and determined to be tissue specific. Compared with high expression of the genomic PSA gene in prostate cells, expression of the transgene driven by the putative PSA promoter is low. This suggests that the identified promoter may be incomplete or may function optimally with additional regulatory elements. To identify the presence of additional regulatory elements, we screened sequences upstream of the PSA promoter and identified a DNA fragment of 822 bp, which enhances PSA gene expression. Combining the newly identified PSA gene regulatory sequence (PSAR) with our previously identified PSA promoter (PCPSA-P) exhibited enhanced expressional activity in the PSA-producing LNCaP cell line. With the addition of 10 to 100 nM dihydrotestosterone, a more than 1000-fold increase in expression was observed as compared to androgen-negative controls. Furthermore, although the combined regulatory element (PSAR)-PSA promoter (PCPSA-P) sequence resulted in high transgene expression in LNCaP cell lines, the combined regulatory element-promoter sequence resulted in minimal expression in the non-PSA-producing prostate cell line PC-3, renal tumor cell line R11, and cervical adenocarcinoma cell line HeLa. The newly identified 822 bp alone could also function as a promoter. Compared with the combined promoter, however, the 822-bp fragment alone demonstrated lower activity and lower responsiveness to androgen stimulation. Our results suggest that coupling the PSA promoter with an upstream regulatory element results in a marked increase in PSA expression, suggesting that the complete PSA promoter contains two functional domains: a proximal promoter and a distal promoter, which can also function as an enhancer. The enhanced gene expression of the new construct, combined with its tissue specificity and androgen responsiveness, in turn provides a foundation for the development of tissue-specific vectors for prostate cancer gene therapy.

Base Sequence↗
PubMed1997

Identification of the cap binding domain of human recombinant eukaryotic protein synthesis initiation factor 4E using a photoaffinity analogue.

Binding of eIF-4E to the 5' m7G cap structure of eukaryotic mRNA signals the initiation of protein synthesis. In order to investigate the molecular basis for this recognition, photoaffinity labeling with [gamma-32P]8-N3GTP was used in binding site studies of human recombinant cap binding protein eIF-4E. Competitive inhibition of this cap analogue by m7GTP and capped mRNA indicated probe specificity for interaction at the protein binding site. Saturation of the binding site with [gamma-32P]8-N3GTP further demonstrated the selectivity of photoinsertion. Aluminum (III)-chelate chromatography and reverse-phase HPLC were used to isolate the binding site peptide resulting from digestion of photolabeled eIF-4E with modified trypsin. Amino acid sequencing identified the binding domain as the region containing the sequence Trp 113-Arg 122.Lys 119 was not identified in sequencing analysis nor was it cleaved by trypsin. These results indicate that Lys 119 is the residue directly modified by photoinsertion of [gamma-32P]8-N3GTP. A detailed understanding of eIF-4E.m7G mRNA cap interactions may lead the way to regulating this essential protein-RNA interaction for specific mRNA in vivo.

Affinity Labels↗
PubMed1997

Expression of functional eIF-4Ehuman: purification, detailed characterization, and its use in isolating eIF-4E binding proteins.

Protein-mRNA cap interactions represent a critical point for regulating gene expression in vivo. For example, a rapid stimulation of gene expression at the mRNA level is mediated by insulin regulating the availability of functional cap-binding protein (eIF-4E). In addition, several viruses modify cap binding proteins to regulate host vs viral gene expression. However, little is known about the molecular details of eIF-4E interactions with m7GTP mRNA caps, with regulatory proteins (e.g., eIF-4E binding proteins), and with proteins within the eIF-4F complex. To study these protein-mRNA and protein-protein interactions in mammalian systems we have constructed a T7 polymerase-driven expression vector containing the coding sequence for human eIF-4E. Recombinant eIF-4Ehuman was purified in a functional state by m7GTP affinity chromatography and Mono Q FPLC. This recombinant protein has biological and physical characteristics that are similar or identical to native eIF-4E. Fluorescence titration studies determined the equilibrium constant for recombinant eIF-4E/m7GTP binding to be 10.1 +/- 0.3 x 10(5) M(-1). To isolate eIF-4E binding proteins, recombinant eIF-4E was linked to agarose beads and incubated with cell lysates. Several proteins were isolated, including a 220-kDa protein that was confirmed to be the p220 subunit of eIF-4F by its proteolysis during incubation with lysates of poliovirus-infected cells. We conclude that recombinant eIF-4E produced in Escherichia coli provides a useful tool for studying eIF-4E/protein and eIF-4E/mRNA cap interactions and their role in regulating mammalian gene expression.

Chromatography, Affinity↗
PubMed1997

National trends in the surgical staging of corpus cancer: a pattern-of-practice survey.

OBJECTIVE: To survey general gynecologists regarding the nature of surgical staging of corpus cancer as practiced in the United States. METHODS: A survey tool was designed to ascertain issues related to surgical staging of corpus cancer among gynecologists in the United States. The survey elicited data pertaining to the demographics and practice characteristics of the respondents. The questionnaire was sent to 700 practicing gynecologists selected randomly from the ACOG membership list. RESULTS: Responses were obtained from 227 physicians; however, only 193 could be analyzed. Most of the respondents classified themselves as general gynecologists (93%) and nonacademicians (90%). In a typical year, 60% evaluated fewer than five patients with corpus cancer. A minority of respondents carry out surgical staging of their patients, which includes total abdominal hysterectomy and bilateral salpingo-oophorectomy (TAHBSO), removal of pelvic and para-aortic lymph nodes, and cytologic evaluation of peritoneal fluid. No uniformity was observed regarding the numeric definition of an appropriate "sampling" (median 5, range 1-25) or "dissection" (median 10, range 1-40) of lymph nodes. Most respondents would not return a corpus cancer patient to the operating room to carry out lymph node dissection if a referring colleague had performed TAHBSO but had not removed the nodes. In such a scenario, private practitioners were approximately three times less likely to reoperate on lymph nodes than academic physicians. CONCLUSION: Complete surgical staging is not performed by most physicians caring for women with corpus cancer. The relatively high proportion of nonresponders and nonevaluable responses suggests that these results should be corroborated by other investigators.

Female↗
PubMed1997

Human chromosome pellicle antibody recognizing centromere protein-C (CENP-C), the main component of the kinetochore.

Recently the antichromosome antisera from several scleroderma patients have been found to recognize the pellicle of metaphase and anaphase chromosomes. In order to identify the pellicle components, we used these antichromosome antisera to screen a human embryonic cDNA library. The sequences of the positive clones are identical to the cDNA gene sequence of CENP-C (centromere protein C), a human centromere autoantigen. This result suggests that CENP-C is a component of the pellicle of human metaphase and anaphase chromosomes.

Anaphase↗
PubMed1997

Importance of a conserved phenylalanine-35 of cytochrome b5 to the protein's stability and redox potential.

Phenylalanine-35, which is a residue of the hydrophobic patch on the surface of cytochrome b5, has been mutated into Tyr35, His35 and Leu35 to elucidate the functions of the Phe35 and give further insight into the roles of the hydrophobic patch and/or aromatic network. The effects of these mutations on the heme environment, denaturation towards heating and the denaturant urea, redox potential and stability of protein were studied. The relative stability of cytochrome b5 and its mutants towards heating has the order Phe35Tyr > wild type > Phe35Leu > Phe35His in the oxidized state and wild type > Phe35Tyr > Phe35Leu > Phe35His in the reduced state. All the mutants exhibit decreased reduction potentials: Phe35Tyr -66 mV, Phe35His -51 mV and Phe35Leu -28 mV, which are more negative than that of the wild type. The order of redox potential reflects the relative stability in the oxidized and reduced states. A method of producing multiple mutants at a single site of a gene is also described for the first time.

Amino Acid Sequence↗
PubMed1997

Palliative irradiation for focally symptomatic metastatic renal cell carcinoma: support for dose escalation based on a biological model.

PURPOSE: Renal cell carcinoma has traditionally been regarded as a radioresistant cancer, yet controversy continues as to whether escalation of the palliative radiation dose can overcome the inherent resistance of such tumors when they metastasize. Recently, the linear quadratic model has emerged as a paradigm to assess biologically effective dose of radiotherapy. This study was undertaken to determine the ability of radiotherapy to palliate focally symptomatic metastatic renal cell carcinoma and to assess whether the delivery of higher biologically effective dose was more likely to bring about a palliative response. MATERIALS AND METHODS: Between 1966 and 1995, 107 patients with renal cell metastases at 150 sites were irradiated with palliative intent. Sites irradiated included bone (89), soft tissue (16), brain (20), spinal cord (9) and pulmonary (16). To determine dose effectiveness the biologically effective dose was calculated according to the formula, Gy10 = total dose (1 + fractional dose/alpha-beta), using an alpha-beta of 10. RESULTS: For the entire group 86% of patients derived a palliative response after treatment with irradiation, while 49% derived a complete palliative response. The median duration of palliation was 6 months (range 1 to 150). With respect to overall (that is, complete and partial) response rates, those presenting with high Karnofsky performance status were most likely to respond (status 70 or greater versus less than 70, 88% versus 78%, p < 0.04). With respect to the rate of complete palliative response, performance status (status 70 or greater versus less than 70, 55% versus 31%, p < 0.03) and the use of higher biologically effective doses of irradiation (Gy10 50 or greater versus less than 50, 59% versus 39%, p = 0.001) were associated with a statistically significant increased rate of response. The independent prognostic value of performance status and higher biologically effective doses of irradiation were maintained in multivariate analysis. CONCLUSIONS: Despite the prevailing concept that renal cell carcinoma is generally resistant to radiotherapy, the overwhelming majority of patients seen at our institution in whom metastatic renal cell carcinoma developed were palliated with radiotherapy. A complete palliative response is more likely when higher biologically effective doses of irradiation are delivered, especially to patients with a relatively high performance status.

Aged↗
PubMed1997

Tissue distribution of Na+/H+ exchanger isoforms NHE2 and NHE4 in rat intestine and kidney.

We present evidence that tissue distribution of two highly conserved Na+/H+ exchanger isoforms, NHE2 and NHE4, differs significantly from previously published reports. Riboprobes unique to each of these antiporters, from 5' (noncoding and coding) and 3' coding regions, were used to analyze mRNA from adult rat kidney and intestine by ribonuclease protection assay and in situ hybridization. In contrast to earlier work that concluded that both NHE2 and NHE4 were expressed throughout the intestine and in the kidney, our data show that there is no NHE2 message in the kidney and NHE4 is not expressed in small or large intestine. Analyses of intestinal epithelial and kidney membrane proteins by an NHE2-specific antibody identified a doublet at < 90 kDa in intestine but not in kidney. NHE2 is highly expressed in the Na(+)-absorptive epithelium of jejunum, ileum, and ascending and descending colon. NHE4 mRNA message is found in the inner medulla of the kidney as previously reported (C. Bookstein, M. W. Musch, A. DePaoli, Y. Xie, M. Villereal, M. C. Rao, and E. B. Chang. J. Biol. Chem. 269: 29704-29709, 1994) and not in the intestine. From these data, we speculate that neither NHE2 nor NHE4 has a role in renal Na+ absorption. NHE2 is likely involved in gut Na+ absorption, whereas NHE4 may have a specialized role in cell volume rectification of inner medullary collecting duct cells. Knowledge of the correct tissue and cell-specific distribution of these two antiporters should help significantly in understanding their physiological roles.

Animals↗
PubMed1997

[Mutation and expression of p53 gene in nasopharyngeal carcinoma, cervical carcinoma and lung cancer].

OBJECTIVE: To investigate the mutation and expression of p53 tumor suppressor gene in nasopharyngeal carcinoma (NPC), cervical carcinoma and lung cancer. METHODS: 24 NPCs, 9 cervical carcinomas and 10 lung cancers were examined by immunohistochemical and PCR-SSCP techniques. RESULTS: 23/24 (90.1%) NPCs, 6/9 (66.7%) cervical carcinomas and 9/10 (90.0%) lung cancers showed p53 overexpression. No NPC or cervical carcinoma had p53 mutations in exons 5-8 of the gene, whereas mutations were found in 5 lung cancers, one in exon 8 and four in exon 5. All five cases showed p53 overexpression. CONCLUSIONS: Overexpression of p53 exists in NPC, cervical carcinoma and lung cancer. It is related to gene mutation in lung cancer, but not in NPC or cervical carcinoma. The DNA tumor viruses may be involved in the overexpression of p53 in NPC and cervical carcinoma.

Exons↗
PubMed1997

[Endoscopic subperiosteal facial rejuvenation].

It is just recently that video endoscopic techniques began to be applied to facial rejuvenation in China. Since July 1995, the authors have performed 15 operations of subperiosteal rejuvenation under the video endoscope, combined with liposuction of the sub-mandible region and the nasolabial fold. The operation uses small incisions, produces satisfactory results with less edema, less numbness and without alopecia. The indications, instrumentation, surgical technique and results and presented and discussed. According to our clinical experience, the best candidates for this operation are those aged from 40 to 55. For the patients about sixty years old, a mini multiplane facelift should be carried out in the cheek and neck region following the subperiosteal facelift. The more elderly patients are not candidates for this operation. We emphasize that the dissected scalp flap should be uplifted to the maximum and anchored on the cranial bone to ensure a satisfactory result.

Adult↗
PubMed1997

[Studies on the quality control of shangke wangshui].

Shangke Wangshui is a new Chinese traditional patent medicine. Its main ingredients Coptis Chinsis Franch, Phellodendron amurense Rupr. and Gardenia jasminoides Ellis. were identified by TLC and PC. The content of active component berberine in Shangke Wangshui was determined by TLC-scanner. This mothod is simple, quick and highly reproducible and can be as a quality control standards for this preparation.

Berberine↗
PubMed1997

[Arginine-glutamine replacement at residue 57 of NADH-cytochrome b5 reductase in Chinese hereditary methemoglobinemia].

OBJECTIVE: To elucidate the molecular mechanism of NADH cytochrome b5 reductase (Cytb5R) deficiency in hereditary methemoglobinemia. METHODS: Cytb5R cDNA was cloned from white blood cells from patient with hereditary methemoglobinemia by RT-PCR method, and the genomic DNA from 3 pedigrees with hereditary methemoglobinemia were analyzed by restriction enzyme analysis. RESULTS: On sequencing the cDNA, two missense mutation were found. One is CGG-->CAG at codon 57 of exon 3, caused Arg-Gln replacement. The other is GAG-->GGG at codon 222 of exon 8. The former mutation abolishes the Msp I recognition site which was confirmed in two of three hereditary methemoglobinemia family. The latter mutation generates a recognition site for Bsi Y I. Amplification of exon 8 by PCR followed by digestion with Bsi Y I revealed no mutation in all patients from the three families. CONCLUSION: Arg57-Gln replacement is responsible for Cytb5R deficiency in the two Chinese pedigrees.

Adult↗
PubMed1997

[Study on red cell enzymes and isoenzymes in patients with leukemia and myelodysplastic syndromes].

OBJECTIVE: To define the prevalence of acquired red cell enzymopathy in leukemia and MDS patients and explore its clinical significance. METHODS: Red cell enzymes (G6PD, 6PGD, PK, ENOL, ADA, PNP,ALD) activities and PK,ADA isoenzymes were assayed by the methods recommended by ICSH and PAGE electrophoresis. RESULTS: The prevalence rate of G6PD deficiency was 43.1%, and of PK deficiency was 27.8%, in leukemia and MDS patients. The prevalence rates of PK, G6PD and PNP deficiency in MDS patients were 50%, 48% and 39.1%, respectively, while of ADA, ENOL and ALD over production in MDS patients were 69. 6%, 40% and 30. 4%, respectively. PK activity was increased in CML, while the PK isoenzyme pattern was normal. Administration of antitumor antibiotics to AL decreased G6PD and 6PGD activities (P < 0.05). ADA2 was expressed in MNC of AML (M4 and M5) and in RBC of CMML, but not expressed in ALL (P < 0.001). CONCLUSION: Determination of enzymes may be used as prognostic parameters in CML,a predictor of antitumor drug resistance in acute leukemia, and a differential parameter between MDS-RA and aplastic anemia and between CML and CMML.

Adolescent↗
PubMed1997

[Unrelated peripheral blood stem cell transplantation for a patient with acute myeloid leukemia].

OBJECTIVE: To carry out unrelated donor peripheral blood stem cell transplantation for treatment of hematological malignancies, and to observe the persistent hematopoietic reconstitution and transplantation related complications. METHODS: A 11-year-old boy with acute myeloid leukemia, who was in second CR, received peripheral blood stem cell transplantation from a unrelated healthy adult donor. The conditioning regimen consisted of FTBI (8Gy), cyclophosphamide (120 mg/kg) and Vp16 (30 mg/kg). The patient received 8. 3 x 10(8) mononuclear cells/kg, 1.079 x 10(8) CD34+ cells/kg and 1. 09 x 10(6) CFU-GM/kg. CsA and MTX were given for prophylaxis of aGVHD. RESULTS: Engraftment with allogeneic peripheral blood stem cells was rapid, ANC reached 1. 30 x 10(9)/L on day 10 post-transplantation, DNA D1S80 showed engraftment on day 23, and the blood type(AB) changed into the donor's (A) on day 120. The patient developed mild aGVHD (I degrees) on day 11 and mild cGVHD on day 143, which were controlled by methylprednisolone and prednisone, respectively. Ten months after transplantation, the patient's blood counts were normal. CONCLUSION: Unrelated donor peripheral blood stem cell can maintain persistent hematopoiesis.

Adult↗
PubMed1997

[Quantitative assessment of allospecific interleukin-2-secreting helper T lymphocyte in cord blood with limiting dilution assay].

OBJECTIVE: In order to investigate whether cord blood transplantation could induce severe graft versus host disease (GVHD) similar to that in bone marrow transplantation. METHODS: The frequency of allospecific IL-2-secreting helper T lymphocyte (AIHTL) in 17 cord blood and 14 adult peripherial blood samples were detected by limiting dilution assay. RESULTS: No statistically significant difference between the cord blood and adult peripheral blood AIHTLs was revealed. CONCLUSION: Alloreactivity of cord blood was the same as that of adult blood. HLA typing and powerful immunosuppressive therapy should be adopted to reduce the incidence of GVHD in cord blood transplantation.

Adult↗