Biomedical subjects

Z Ye

Publications and source records attributed to Z Ye.

At least 19 recordsLinked to original sources

PubMed2003

[Reoperation for a Starr-Edwards ball valve prosthesis implanted in mitral position 31 years ago].

The patient is a 61-year-old woman who had undergone mitral valve replacement with the Starr-Edwards cloth-covered ball valve 31 years ago. She had dyspnea on effort 1 month before admission. The echocardiography revealed mitral and tricuspid regurgitation. Re-replacement of the mitral prosthetic valve with an ATS valve and tricuspid annuloplasty were successfully performed without any complication. The cloth wear of the Starr-Edwards ball valve cage was recognized and no thrombus was found at operation. To our knowledge, there has been no such a reoperative case who underwent so long postoperative period after initial implantation of the Starr-Edwards ball valve in Japan. This experience made us realize again the importance of attention to the complications related to a prosthetic valve like a cloth wear during long-term follow-up for the Starr-Edwards ball valve.

Female↗

PubMed2002

Breast cancer in relation to induced abortions in a cohort of Chinese women.

The possible influence of induced abortion on breast cancer risk was assessed in a cohort of 267 040 women enrolled in a randomised trial of breast self-examination in Shanghai, China. Based on answers to a baseline questionnaire, subsequent breast cancer risk was not significantly associated with ever having an induced abortion. After adjustment for potential confounders, the relative risk estimate was 1.06 (95% C.I.: 0.91, 1.25), and there was no trend in risk with number of abortions. Analysis of data from more detailed interviews of 652 cases and 694 controls from the cohort yielded similar results. There was also no overall increase in risk in women with induced abortion after first birth. Few women had undergone an abortion after 13 weeks gestation or before their first child. Although increases in risk were observed in such women, they were not statistically significant and could have been due to recall bias. Abortions as they have been performed in China are not an important cause of breast cancer.

Abortion, Induced↗

PubMed2002

Restriction enzymes in the analysis of genetic alterations responsible for cancer progression.

BACKGROUND: Molecular approaches are increasingly being employed to dissect the genetic changes accompanying tumour formation. These methods can often be confusing to the non-specialist as they include complex molecular steps. This can reduce the usefulness of such molecular data to clinicians. The authors aim to aid interpretation of molecular studies in general by presenting a comprehensive review of one molecular approach, i.e. the use of restriction enzymes in molecular studies of tumour development. METHOD: A review was made of the molecular studies that have employed restriction enzymes in gastrointestinal cancer research. These studies have used restriction enzymes to analyse point mutation induction, gene methylation status and the deletion of chromosomal loci. In addition, emphasis is placed on some of the important considerations for the molecular analysis of tumours that can affect the molecular data obtained. RESULTS: Restriction enzyme digestion has played, and continues to play, a major role in analysing the genetic changes in cancer. Many adaptations of basic restriction enzyme methodologies have enhanced the application of this approach in cancer genetics. CONCLUSION: The availability of 200 different restriction enzymes, each recognizing different sequences in DNA, has been invaluable in studying cancer genetics. It is hoped that current advances in protein engineering will facilitate the creation of novel restriction enzymes with tailor-made sequence specificities. This will further improve the applicability of restriction enzymes in cancer genetics.

DNA Methylation↗

PubMed2002

In vitro interactions between gamma deltaT cells, DC, and CD4+ T cells; implications for the immunotherapy of leukemia.

BACKGROUND: Gamma deltaT cells contribute to immune defense against infectious organisms and some malignancies, but the process of activation and proliferation of these cells is not well understood. It is known that the immune response of gamma deltaT cells is not MHC-dependent, but is likely based on direct recognition of surface peptides and non-peptide ligands. This study examined whether DCs and CD4(+) T cells can participate in the activation of gamma deltaT cells. METHOD: Peripheral blood gamma deltaT cells were co-cultured with CD34-derived autologous DCs and CD4(+) T cells using contact-dependent cultures and transwell systems. Proliferation, immunophenotyping, and cytotoxicity assays determined the extent of gamma deltaT cell proliferation and cytotoxicity. RESULTS: Human gamma deltaT cells expanded 221.3 +/- 76-fold in cultures with DCs, and 165.7 +/- 76.6-fold with CD4(+) T-cells alone. Proliferation was enhanced (1949.8 +/- 261.3-fold) when gamma deltaT cells were cultured with both DC and CD4(+) T cells. Proliferation was contact-dependent, and resulted in the expansion of V delta1+ or V delta2+ cells cytotoxic against several leukemic cell-lines, but not against allogeneic PHA-induced lymphoid blasts. Ligation of the T-cell receptor with anti-pan-delta Ab significantly up-regulated cytotoxicity against K562, KBM-5 and KG1a, and normal BM, but not against Molt-4, allogeneic EBV-transfected B cells and allogeneic PHA-blasts. Minimal cytotoxic activity was shown against allogeneic marrow colony-forming units granulocyte-macrophage and erythrocyte colony-forming units. CONCLUSION: DCs can participate in the activation of gamma deltaT cells against specific autologous targets, and cytotoxicity can be enhanced by further stimulation via the T-cell receptor.

CD11c Antigen↗

PubMed2001

Statistics of the Lyapunov exponent in one-dimensional layered systems.

Localization of acoustic waves in a one-dimensional water duct containing many randomly distributed air filled blocks is studied. Both the Lyapunov exponent and its variance are computed. Their statistical properties are also explored extensively. The results reveal that in this system a single-parameter scaling is generally inadequate no matter whether the frequency we consider is located in a pass band or in a band gap. This contradicts the earlier observations in an optical case. We compare the results with two optical cases and give a possible explanation of the origin of the different behaviors.

Journal Article↗

PubMed2001

Acoustic pulse propagation and localization in bubbly water.

Acoustic pulse propagation in bubbly water is studied using a self-consistent method. The acoustic transmission and backscattering are evaluated numerically. Under proper conditions, the localization of acoustic waves is identified within a range of frequency. The results show that when a short pulse is transmitted the waves of frequencies within the localization regime will be trapped in the system and reveal a coherent behavior. A phase diagram approach is used to describe the localization behavior.

Journal Article↗

PubMed2001

Effect of influenza virus matrix protein and viral RNA on ribonucleoprotein formation and nuclear export.

The formation of influenza virus ribonucleoprotein (RNP) is a necessary step in viral assembly and maturation in infected cells, but the mechanism remains incompletely understood. Influenza virus proteins such as matrix (M1) and cellular proteins have been implicated in assembly and transport of RNP. To study the assembly of RNP and the translocation of RNP complexes in cells, RNPs were reconstituted from nucleoprotein (NP), M1, and viral RNA (vRNA) synthesized in vitro. The syntheses were accomplished using specific plasmids in a system coupling transcription and translation under the control of the T7 promoter. The density of the resulting RNP complexes was analyzed by glycerol gradient centrifugation and the morphology was examined by transmission electron microscopy. Protomers of NP self-assembled into circular oligomers regardless of the presence of vRNA or M1. However, helical structures similar in conformation and density to RNPs purified directly from influenza virus were formed only when M1 and vRNA were also present. In the absence of vRNA, no helical structures were formed from NP and M1. The plasmids also contained the CMV promoter, which permitted expression of M1, NP, and vRNA in Madin-Darby canine kidney (MDCK). M1 and NP were both present in the cytoplasm of MDCK also expressing vRNA, but NP was retained in the nucleus of cells expressing M1 without vRNA. Our data demonstrate for the first time that vRNA and M1 together promote the self-assembly of influenza virus NP into the quaternary helical structure typical of the viral RNP. The results also indicate that the interaction of NP with vRNA and M1 in a system devoid of other viral proteins can lead to translocation of RNP from nucleus to cytoplasm.

Active Transport, Cell Nucleus↗

PubMed2001

Theoretical analysis of acoustic stop bands in two-dimensional periodic scattering arrays.

This paper presents a theoretical analysis of the recently reported observation of acoustic stop bands in two-dimensional scattering arrays [Robertson and Rudy, J. Acoust. Soc. Am. 104, 694 (1998)]. A self-consistent wave scattering theory, incorporating all orders of multiple scattering, is used to obtain the wave transmission. The band structures for the regular arrays of cylinders are computed using the plane-wave expansion method. The theoretical results compare favorably with the experimental data.

Journal Article↗

PubMed2001

Acoustic wave propagation in a one-dimensional layered system.

Propagation of acoustic waves in a one-dimensional water duct containing many air filled blocks is studied by the transfer matrix formalism. Energy distribution and interface vibration of the air blocks are computed. For periodic arrangement, band structure is calculated analytically, whereas the Lyapunov exponent and its variance are computed numerically for random situations. A distinct collective behavior for localized waves is found. The results are also compared with optical situations.

Journal Article↗

PubMed2001

CD3-mediated activation of tumor-reactive lymphocytes from patients with advanced cancer.

Lymphocytes from blood or tumors of patients with advanced cancer did not proliferate and produced very low levels of tumor necrosis factor and IFN-gamma when cultured with autologous tumor cells. Proliferation and lymphokine production dramatically increased in the presence of beads conjugated with mAbs to CD3 plus mAbs to CD28 and/or CD40, and the lymphocytes destroyed the tumor cells. Expression density of CD3 concomitantly increased from low to normal levels. Furthermore, beads providing a CD3 signal (in combination with CD28 or CD28 plus CD40) gave partial protection against the inhibitory effect of transforming growth factor type beta1 on lymphocyte proliferation and production of tumor necrosis factor and IFN-gamma. MHC class I-restricted cytolytic T cells lysing autologous tumor cells in a 4-h Cr(51) release assay were generated when peripheral blood leukocytes were activated in the presence of autologous tumor cells and anti-CD3/CD28 or anti-CD3/CD28/CD40 beads. Experiments performed in a model system using anti-V-beta1 or anti-V-beta2 mAbs to activate subsets of T cells expressing restricted T cell receptor showed that lymphocytes previously activated by anti-V-beta can respond to CD3 stimulation with vigorous proliferation and lymphokine production while retaining their specificity, also in the presence of transforming growth factor type beta1. Our results suggest that T lymphocytes from cancer patients can proliferate and form Th1 type lymphokines in the presence of autologous tumor cell when properly activated, and that antigen released from killed tumor cells and presented by antigen-presenting cells in the cultures facilitates the selective expansion of tumor-directed, CD8(+) cytolytic T cells.

Antibodies, Monoclonal↗

PubMed2001

Ablation of NF1 function in neurons induces abnormal development of cerebral cortex and reactive gliosis in the brain.

Neurofibromatosis type 1 (NF1) is a prevalent genetic disorder that affects growth properties of neural-crest-derived cell populations. In addition, approximately one-half of NF1 patients exhibit learning disabilities. To characterize NF1 function both in vitro and in vivo, we circumvent the embryonic lethality of NF1 null mouse embryos by generating a conditional mutation in the NF1 gene using Cre/loxP technology. Introduction of a Synapsin I promoter driven Cre transgenic mouse strain into the conditional NF1 background has ablated NF1 function in most differentiated neuronal populations. These mice have abnormal development of the cerebral cortex, which suggests that NF1 has an indispensable role in this aspect of CNS development. Furthermore, although they are tumor free, these mice display extensive astrogliosis in the absence of conspicuous neurodegeneration or microgliosis. These results indicate that NF1-deficient neurons are capable of inducing reactive astrogliosis via a non-cell autonomous mechanism.

Alleles↗

PubMed2001

Novel gelatin-adriamycin sustained drug release system for intravesical therapy of bladder cancer.

To reduce recurrence in the patients with bladder cancer after tumor removal through open surgery or transurethral resection, a form of gelatin-adriamycin sustained drug release system was developed and its release kinetics both in vitro and in vivo, its efficacy in inhibiting BIU-87 bladder tumor cell growth in vitro and its safety in vivo were studied. The results showed that this system controlled adriamycin release over a period of 21 days in vitro and significantly inhibited BIU-87 cell growth. When this system was injected into rabbit bladder, it sustained adriamycin release for 12 days and the released drug could diffuse 1 cm around the injection point. No major complications were observed except minor acute nonspecific cystitis that could be tolerated well by the animals. This study suggests the possibility of applying this system locally in treating bladder cancer.

Administration, Intravesical↗

PubMed2001

Copper(II) ion induced monolayer formation of p-tert-butylthiacalix[4]arene at the air-water interface.

The monolayer properties of p-tert-butylthiacalix[4]arene (TCA) at the air-water interface was investigated by the measurements of surface pressure-area isotherms. However, TCA only exists as a trimmer aggregate on the subphase of deionized water. Copper(II) ion in the subphase can induce the monolayer formation of TCA. The UV-Vis spectra and FTIR spectra of the transferred films suggested that the monolayer forrmation was fulfilled through the coordination of copper(II) ion to TCA at the air-water surface.

Air↗

PubMed2001

Human gammadelta(+) T lymphocytes have in vitro graft vs leukemia activity in the absence of an allogeneic response.

Refractory acute lymphoblastic leukemia (ALL) is often incurable, and relapse rates following allogeneic bone marrow transplantation (BMT) remain high. We have reported that patients who develop increased numbers of gammadelta(+) T cells soon after BMT are significantly less likely to relapse. We now show in seven donor/recipient pairs that donor-derived Vdelta1(+)CD4(-)CD8(-)gammadelta(+) T cells are activated and proliferate in response to recipient primary ALL blasts. In addition, these cells have been shown to bind and lyse the recipient ALL blasts. Separately, gammadelta(+) T cells proliferate poorly or not at all in mixed lymphocyte culture against HLA-mismatched unrelated stimulator cells. These observations suggest that allogeneic gammadelta(+) T cells could be an effective immunotherapeutic strategy against refractory disease without the risk of graft-versus-host disease.

Cytotoxicity, Immunologic↗

PubMed2001

Bcl-xL expression after contusion to the rat spinal cord.

After contusion-derived spinal cord injury, (SCI) there is localized tissue disruption and energy failure that results in early necrosis and delayed apoptosis, events that contribute to chronic central pain in a majority of patients. We assessed the extent of contusion-induced apoptosis of neurons in a known central pain-signaling pathway, the spinothalamic tract (STT), which may be a contributor to SCI-induced pain. We observed the loss of STT cells and localized increase of DNA fragmentation and cytoplasmic histone-DNA complexes, which suggested potential apoptotic changes among STT neurons after SCI. We also showed SCI-associated changes in the expression of the antiapoptotic protein Bcl-xL, especially among STT cells, consistent with the hypothesis that Bcl-xL regulates the extent of apoptosis after SCI. Apoptosis in the injured spinal cord correlated well with prompt decreases in Bcl-xL protein levels and Bcl-xL/Bax protein ratios at the contusion site. We interpret these results as evidence that regulation of Bcl-xL may play a role in neural sparing after spinal injury and pain-signaling function.

Animals↗

PubMed2001

[Fingerprints of Radix Salviae Miltiorrhizae].

OBJECTIVES: To establish fingerprints of the Radix Salviae Miltiorrhizae from Shangluo Dansben Base of Tasly Group Co. Ltd., and to compare the fingerprints with fingerprints of Radix Salviae Miltiorrhizae from Tianjin market of medicinal materials. METHOD: By HPLC to establish fingerprint of water-soluble extract of Radix Salviae Miltiorrhizae. CONCLUSION: The fingerprints of 10 batches of Radix Salviae Miltiorrhizae from Shangluo conformed to the requirements of fingerprints of Chinese medicinal materials issued by State Drug Administration in 2000. And there were obvious differences between the fingerprints of Radix Salviae Miltiorrhizae from Shangluo and from Tianjin market of medicinal materials.

Chromatography, High Pressure Liquid↗

PubMed2001

[Intraoperative ultrasonographic detection of liver metastasis from tumors of the digestive tract].

OBJECTIVE: To ascertain the value of intraoperative ultrasonography to early detect liver metastasis from tumors of the digestive tract. METHODS: Intraoperative ultrasonography (US) of the liver was performed in 176 patients with confirmed diagnosis of cancer of the stomach and colon. All the nodules detected were either resected or needle biopsied for histological diagnosis. The results of the liver US were compared with those of pre-operative trans-abdominal US, CT scanning and intraoperative exploration. RESULTS: Liver metastasis was detected by intraoperative US in 43 of the 176 patients (24.4%), with a total of 81 nodules found. Liver metastasis was confirmed histologically in 42 of the 43 cases (97.7%), the frequency of which was significantly higher than that of preoperative transabdominal US, CT scan and surgical exploration (P < 0.05, P < 0.01). It was particularly superior for the detection of liver metastasis less than 2 cm in diameter. CONCLUSION: Intraoperative ultrasonography is sensitive enough to early detect tumors of the stomach and colon metastasized to the liver.

Adult↗

PubMed2001

[Application of inter-fluorescence in situ hybridization of chromosome 13/21 alpha satellite probe in amniotic cells for prenatal diagnosis trisomy 21 syndrome].

OBJECTIVE: To investigate the prenatal diagnosis of trisomy 21 syndrome using chromosome 13/21 alpha satellite probe fluorescence in situ hybridization (FISH) on uncultured interphase cells from amniotic fluid. METHODS: The interphase amniocytes of 10 fetuses who were detected normal and 3 fetus who were detected trisomy by prenatal cytogenetic diagnosis were selected. We did FISH which used chromosome 13/21 alpha satellite probe directly on the uncultured amniocytes of these 13 samples. RESULTS: The total rate of the hybridization was 36.7% and 38.6% in control group and observation group respectively, showed no significantly difference. There were four signals in the nucleus, two groups were 36.5% and 3.9% respectively, there were five signals in the nucleus, two groups were 4.0% and 36.1% respectively. The control group and observation group showed significantly difference by the statistical chi 2 values (P < 0.01). Trisomy 21 syndrome was diagnosed when nucleus of five signals accounted for more than 36.1%. CONCLUSION: FISH with Chromosome 13/21 alpha satellite probe is a valuable method for rapid prenatal diagnosis of trisomy 21 syndrome.

Amniotic Fluid↗