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Biomedical subjects

Z G Xu

Publications and source records attributed to Z G Xu.

18 recordsLinked to original sources
PubMed2001

Insight into hepatocellular carcinogenesis at transcriptome level by comparing gene expression profiles of hepatocellular carcinoma with those of corresponding noncancerous liver.

Human hepatocellular carcinoma (HCC) is one of the most common cancers worldwide. In this work, we report on a comprehensive characterization of gene expression profiles of hepatitis B virus-positive HCC through the generation of a large set of 5'-read expressed sequence tag (EST) clusters (11,065 in total) from HCC and noncancerous liver samples, which then were applied to a cDNA microarray system containing 12,393 genes/ESTs and to comparison with a public database. The commercial cDNA microarray, which contains 1,176 known genes related to oncogenesis, was used also for profiling gene expression. Integrated data from the above approaches identified 2,253 genes/ESTs as candidates with differential expression. A number of genes related to oncogenesis and hepatic function/differentiation were selected for further semiquantitative reverse transcriptase-PCR analysis in 29 paired HCC/noncancerous liver samples. Many genes involved in cell cycle regulation such as cyclins, cyclin-dependent kinases, and cell cycle negative regulators were deregulated in most patients with HCC. Aberrant expression of the Wnt-beta-catenin pathway and enzymes for DNA replication also could contribute to the pathogenesis of HCC. The alteration of transcription levels was noted in a large number of genes implicated in metabolism, whereas a profile change of others might represent a status of dedifferentiation of the malignant hepatocytes, both considered as potential markers of diagnostic value. Notably, the altered transcriptome profiles in HCC could be correlated to a number of chromosome regions with amplification or loss of heterozygosity, providing one of the underlying causes of the transcription anomaly of HCC.

Carcinoma, Hepatocellular↗
PubMed2001

The latency pattern of Epstein-Barr virus infection and viral IL-10 expression in cutaneous natural killer/T-cell lymphomas.

The nasal type, extranodal natural killer or T(NK/T)-cell lymphoma is usually associated with latent Epstein-Barr virus (EBV) infection. In order to elucidate the EBV gene expression patterns in vivo, we examined eight patients with cutaneous EBV-related NK/T-cell lymphomas, including six patients with a NK-cell phenotype and two patients with a T-cell phenotype. The implication of EBV in the skin lesions was determined by the presence of EBV-DNA, EBV-encoded nuclear RNA (EBER) and a clonality of EBV-DNA fragments containing the terminal repeats. Transcripts of EBV-encoded genes were screened by reverse transcription- polymerase chain reaction (RT-PCR), and confirmed by Southern blot hybridization. The expression of EBV-related antigens was examined by immunostaining using paraffin-embedded tissue sections and cell pellets of EBV-positive cell lines. Our study demonstrated that all samples from the patients contained EBV nuclear antigen (EBNA)-1 mRNA which was transcribed using the Q promoter, whereas both the Q promoter and another upstream promoter (Cp/Wp) were used in EBV-positive cell lines, B95.8, Raji and Jiyoye. Latent membrane protein-1 (LMP-1) mRNA was detected in seven of eight patients and all cell lines, whereas EBNA-2 transcripts were found only in the cell lines. Immunostaining showed no LMP-1, EBNA-2 or ZEBRA antigens in the paraffin-embedded tissue sections, although they were positive in the cell line cells. Latent BHRF1 transcripts encoding bcl-2 homologue and BCRF1 transcripts encoding viral interleukin (vIL)-10 were detected in one and two of eight patients, respectively. A patient with NK-cell lymphoma expressing both transcripts died of rapid progression of the illness. Our results indicate that the restricted expression of the latency-associated EBV genes and the production of vIL-10 and bcl-2 homologue may favour tumour growth, evading the host immune surveillance.

Adolescent↗
PubMed2001

Cloning, mapping, and characterization of a human homologue of the yeast longevity assurance gene LAG1.

We have identified LASS2, a previously unknown human homologue of the yeast longevity assurance gene LAG1. The LASS2 transcript is highly expressed in liver and kidney, which is very different from the expression of the previously identified human LAG1 homologue LAG1Hs-1. Radiation hybrid mapping studies indicated that LASS2 is located on chromosome 1q11. Yeast two-hybrid screening and glutathione S-transferase pull-down assays showed that the LASS2 protein interacts with several membrane-associated receptors or transporters. Furthermore, LASS2 protein was able to inhibit the colony formation of human hepatoma cells in vitro, which suggests that this gene may be involved in the regulation of cell growth.

Amino Acid Sequence↗
PubMed2000

Polymorphism analysis of Epstein-Barr virus isolates from patients with cutaneous natural killer/T-cell lymphoproliferative disorders: A possible relation to the endemic occurrence of these diseases in Japan.

Certain forms of cutaneous lymphomas in Asia are associated frequently with Epstein-Barr virus (EBV) infection, whereas such cases are less common in western countries. The virus-related peptides, EBV-determined nuclear antigen (EBNA)-2 and the latent membrane protein (LMP)-1, play an essential role in cell transformation. The polymorphisms of these EBV genes may be related to their transforming abilities. In order to clarify the viral subtype that may be involved in the incidence of EBV-associated lymphomas, we analyzed the EBNA-2 and LMP-1 gene polymorphisms and mutations in healthy adults and in patients with EBV-associated cutaneous natural killer(NK)/T-cell lymphoproliferative disorders in Japan. In EBV-related cutaneous lymphoproliferative disorders, EBV subtype 1 was found in all 15 cases, and 1 sample contained a dual infection with subtypes 1 and 2. All EBV isolates from our patients lost a Xho-1 site in exon 1 of the LMP-1 gene, and 7 of 13 cases had a Nco-1 site within the promoter region. All isolates without the LMP-1-Xho-1 site had a 30 bp deletion in the carboxy terminus of the LMP-1 gene, except for the isolate from a patient with angioimmunoblastic lymphadenophathy-like T-cell lymphoma in which a novel Nco-1 site was present in exon 1. Eleven of fourteen throat washings from healthy adults which contained EBV-DNA harbored EBV subtype 1, and the EBNA2 region was not amplified in the other 3 samples. The Xho-1 site was lost in 12 (86%) of 14 isolates and the 30 bp deletion was present in 11 (78%) of 14 isolates from the throat washings. The findings indicate that the predominant EBV isolate from Japanese healthy adults and patients with cutaneous NK/T-cell lymphoproliferative disorders is subtype 1 with a 30 bp deletion and loss of a Xho-1 site in the LMP-1 gene. Since previous data indicated that either subtype 1 or the 30 bp deletion variant possesses high tumorigenic activity, the prevalence of subtype 1 containing these mutations might be responsible for the high incidence of EBV-associated lymphoproliferative disorders in Japan.

Adaptor Proteins, Signal Transducing↗
PubMed1993

[Role of upper jugular node dissection in the management of supraglottic cancer of N0 category].

The results of management of neck nodes in 295 cases with supraglottic laryngeal carcinoma were reviewed. Different approaches had been adopted. For N1-N3 cases RND was instituted routinely; for N0 cases, RND, which has been advocated by many authors, seems to be an overtreatment. We prefer upper jugular node dissection for pathologic evaluation. Out of 86 N0 cases, only 6 were proved to be positive for metastases. The 3 and 5 year survival rates for this series were 89.5% and 75.3% respectively which were comparable with those reported to have RND.

Adult↗
PubMed1992

[Hybridization experiments using Anopheles minimus from Guangxi and Yunnan].

Hybridization experiments were conducted by forced mating between Anopheles minimus from Guangxi (G) and Yunnan (Y). F1 hybrid females were all fertile with normally developed ovaries. (Y female x G male) F1 males were all sterile, with abnormally enlarged testes. (G female x Y male) F1 males, though fertile, showed somewhat atrophic testes, and when they were back crossed with parental females, the latter produced eggs with very low hatching rate. Ovarian nurse cell polytene chromosomes from F1 hybrid females showed partial asynapsis in X chromosome as well as in autosonles, asynapsis at 38 zone in 3L being the most constant. It was obvious that there was definite, though partial, reproductive isolation between An minimus from Guangxi and that from Yunnan. Whether they are sibling species remains to be further investigated (Figs. 1-8).

Animals↗
PubMed1992

[The choice of treatment in acute hemorrhagic necrotic pancreatitis: medical or surgical?].

In recent ten years, physicians and surgeons in Beijing Tong Ren Hospital cooperated well in the treatment of acute hemorrhagic necrotic pancreatitis. Twenty four cases were chosen to determine whether medical conservative or surgical operative treatment should be given. In the surgical operation group there were fourteen cases. Twelve cases survived and the remaining two died. In the medical conservative group only one of the ten cases died. The overall mortality of the twenty four cases of acute hemorrhagic pancreatitis was 12.5%. In our study, the indications for operation were as follows: (1) Presence of more than five positive diagnostic criteria. (2) Accompaniment of gall stone. (3) Inability to differentiate with other acute surgical abdominal emergencies such as intestinal obstruction.

Acute Disease↗
PubMed1991

[Preliminary experience in salvage treatment for advanced recurrent cancers of the head and neck].

Sixteen patients with far advanced recurrent malignancies (later than Stage IV) of the head and neck were treated with radical salvage surgery combined with radiotherapy, chemotherapy, immunotherapy, laser and/or traditional Chinese medicine. The 2- and 3- year survival rates were 56.3% (9/16) and 37.5% (6/16), which were superior to 6.3% (1/16) and 6.3% (1/16) of similar patients who refused treatment. The authors are of the opinion that aggressive treatment should be attempted for patients with far advanced recurrent cancers of the head and neck.

Adolescent↗
PubMed1986

Experimental study and clinical use of the fasciosteal flap.

Thirty-seven domestic rabbits, 4 dogs, and 2 freshly amputated human limbs were divided into three groups as three different models of fasciosteal flaps that were taken from the distal radii or the tibiae. Through the methods of histology, fluorochrome bone labeling, and perfusing stain, it was confirmed that viability of the bone graft can be maintained by blood flow by means of the fascial route. This technique was used for treating eight patients with nonunion of such different fractured sites as the scaphoid, the talus, and so forth or with osteomyelitic tibial defects or both skin and tibial defects. With 8 to 15 months of follow-up, the osteomyelitis cleared uneventfully and the fracture healed. Patients recovered their normal function. We think that there are at least three routes for the blood supply from deep fascia to bone: direct blood supply, blood supply by means of bone membrane, and blood supply by means of the intermuscular septum. We feel that the fasciosteal flap is an ideal random-pattern vascularized bone graft.

Adolescent↗
PubMed1985

Effect of (E)-5-(2-bromovinyl)-2'-deoxyuridine on the growth and viral capsid antigen expression of Epstein-Barr virus-associated tumor (B-95-8) cells transplanted to nude mice.

When persistently Epstein-Barr virus (EBV)-infected lymphoblastoid (B-95-8) cells were transplanted subcutaneously or intracerebrally to nude mice of either BALB/c or NIH background, tumors developed, and the tumor cells spontaneously expressed viral capsid antigen (VCA). This model was used to evaluate the in vivo anti-EBV activity of (E)-5-(2-bromovinyl)-2'-deoxyuridine (BVDU), a highly potent and selective antiherpes agent, which was recently shown to inhibit several parameters of EBV infection in vitro. When administered intraperitoneally at 200 mg/kg/day for 4 weeks, or 500 mg/kg/day for 2 weeks, starting immediately after B-95-8 cell inoculation, BVDU effectively reduced tumor growth and VCA expression of either subcutaneously or intracerebrally inoculated B-95-8 cells.

Animals↗
PubMedDate not supplied

Site-dependence of invasiveness of ECA109 human oesophageal carcinoma cells in nude mice.

ECA109 human oesophageal carcinoma cells were injected either subcutaneously or intraperitoneally into BALB/CATc 1-nu/nu mice. After 23 weeks tumours were examined histologically and by scanning electron microscopy. Subcutaneous ECA109 tumours were well-delineated without signs of invasion. By contrast, intra-abdominal tumours invaded into the abdominal wall and abdominal organs. This result provides us with another example of site-dependence of invasion in vivo.

Animals↗