Biomedical subjects

Zhen Cai

Publications and source records attributed to Zhen Cai.

31 records · Page 2Linked to original sources

PubMed2004

Human cytomegalovirus protects multiple myeloma cell line KM3 cells from apoptosis induced by growth factor withdrawal.

BACKGROUND: There is a higher rate of cytomegalovirus (CMV) reactivation in patients with multiple myeloma after an autologous stem cell transplantation, but no attention has been given thus far to a possible pathogenetic interplay between CMV and multiple myeloma. CMV can infect many kinds of cells, and CMV infection has been shown to inhibit apoptotic responses in several cell systems. In this study the authors investigated the alterations in apoptosis in the multiple myeloma cell line KM3 after infection with CMV and proposed a possible mechanism. METHODS: KM3 cells were infected with 100, 10, or 1 TCID50 of CMV and then cultured in serum-free RPMI 1640. An RT-PCR-based assay was used to detect mRNA expression of CMV-IE, glyceraldehyde-3-phosphate dehydrogenase (GAPDH), and IL-6 in CMV-infected and mock-infected cells. Flow cytometry was used to detect apoptotic cells. CMV particles and apoptotic cells were also examined with an electron microscope. RESULTS: CMV-infected KM3 cells clearly expressed immediate early (IE) antigen mRNA when compared to uninfected cells, and there were fewer apoptotic cells among cells treated with 100 or 10 TCID50 of CMV after culturing in serum-free RPMI 1640. CMV particles were observable in infected cells under an electron microscope. Expression of IL-6 mRNA increased after infection. CONCLUSION: CMV can infect the multiple myeloma cell line KM3, inhibit the apoptotic response in these cells after apoptosis induction in serum-free culture, and increase the expression of IL-6 mRNA.

Apoptosis↗

PubMed2004

[Monocytic differentiation of bone marrow-derived hematopoietic precursors controlled by mesenchymal stem cell in absence of exogenous hematopoitic growth factors].

To study the hematopoiesis controlled by mesenchymal stem cell (MSC) in the absence of exogenous hematopoietic growth factors in vitro. MSCs were isolated and cultured in vitro, and the hematopoietic growth factors secreted by MSCs were detected with RT-PCR. Mononuclear cells from bone marrow were seeded in 6-well plates in which MSCs had been seeded as feeder cells. After culture for 3 weeks, cells in coculture were observed with wright's staining, immunocytochemisty and flow cytometry analysis to identify the lineage of hematopoietic cells. The results showed that SCF, Flt3 Ligand and M-CSF were detected in MSCs, but G-CSF and GM-CSF were not detected. In the coculture system, a number of round shape cells grew adherently to the spindle shape MSCs after coculture for 2 weeks. Wright's staining displayed that the round shape cells had abundant plasma and kidney-shaped or oval nucleus, some cells had typical monocytic morphology, and Flow cytometry analysis displayed that the CD45+ round shape cells were positive for CD14 and were negative for CD15, CD7, CD19, CD41 and glycoporin A. Our data suggested that hematopoietic precursors from bone marrow were able to differentiate into monocyte controlled by mesenchymal stem cells in vitro in absence of exogenous hematopoitic growth factors, the committed differentiation might be regulated by the hematopoietic growth factors secreted by MSCs, and the cell-cell contact might also contribute to the differentiation.

Bone Marrow Cells↗

PubMed2004

[Study on the relationship between the inhibitors of apoptosis proteins and the apoptosis of myelodysplastic syndrome cell line cells induced by aclacinomycin in vitro].

To explore the correlation between the cellular inhibitors of apoptosis proteins (cIAPs) and the apoptosis of myelodysplastic syndrome (MDS) cell line (RAEB type) cells induced by aclacinomycin (ACM), the apoptosis of MDS cell line MUTZ-1 cells induced by ACM was analyzed with terminal deoxyribonucleotidy transferase mediated dUTP-biotin nick end labeling (TUNEL) technique. By using semi-quantitative reverse transcriptase polymerase chain reaction (RT-PCR), the expression levels of cIAP-1 and cIAP-2 mRNA in MUTZ-1 cells were assayed. The results showed as follow: (1) Using 0.5 micromol/L, 1.0 micromol/L ACM treated cells for 24 hours, the relative expression level of cIAP-1 mRNA (cIAP-1/GAPDH) was lower than those in the untreated cell group (P=0.002, 0.0002, respectively). (2) Using 0.5 micromol/L ACM treated for 6, 12, 24 hours, the relative expression level of cIAP-1 mRNA was 0.95 +/- 0.04, 0.73 +/- 0.05, 0.38 +/- 0.07, respectively and the relative expression level of cIAP-1 mRNA was correlated negatively with the time treated by ACM (r=-0.996, P <0.01). (3) Using 0.5 micromol/L ACM treated for 3, 6, 12, 24 hours, the relative expression level of cIAP-2 mRNA was 1.17 +/- 0.06, 0.91 +/- 0.03, 0.69 +/- 0.07 and 0.00 +/- 0.00, respectively and relative expression level of CIAP-2 mRNA was correlated negatively with the time treated by ACM (r=-0.091, P <0.01). (4) The percentages of TUNEL positive cells were correlated negatively with the relative expression level of CIAP1 and CIAP2 mRNA (r=-0.984, -0.959 and P=0.002, 0.013 respectively) when treated with increasing concentration of ACM. In conclusion, ACM can induce significantly MUTZ-1 cell apoptosis via suppressing expression of anti-apoptotic gene cIAP-1 and cIAP-2 mRNA.

Aclarubicin↗

PubMed2004

[Mechanisms of sodium ferulate inhibition of collagen synthesis in hepatic stellate cells].

AIM: To study the mechanisms of sodium ferulate (SF) on inhibition of collagen synthesis in hepatic stellate cells. METHODS: Collagen synthesis was analyzed by measuring 3H-proline incorporation. ELISA method was used to study the effect of SF on transforming growth factor beta1 (TGFbeta1) level in cultured HSC-T6 cell. The effect of SFon the TGFbeta1 activity in the supernatant of culture was analyzed by mink lung epithelial cell (Mv1Lu) proliferation inhibition by MTT assay. RESULTS: SF inhibited collagen synthesis in hepatic stellate cells stimulated with TGFbeta1. SF was shown to decrease TGFbeta1 level in the supernatant of HSC-T6 increased by oxidative stress. TGFbeta1 activity was intervened by SF. CONCLUSION: SF could decrease collagen synthesis, with mechanism may be associated with that SF intervened TGFbeta1 activity, and reduced the level of TGFbeta1 increased by oxidative stress.

Animals↗

PubMed2004

[Treatment of childhood leukemia with unrelated donor allogeneic bone marrow transplantation].

OBJECTIVE: Allogeneic bone marrow transplantation has been established as a standard method for the treatment of a range of malignant and non-malignant hematologic diseases in children. Unfortunately, fewer than 30% of patients have a human leukocyte antigen (HLA)-matched sibling. Advances in our understanding of the HLA system and the development of large international donor registries encourage the increasing use of unrelated donors as an alternative source of stem cells. The purpose of this study was to evaluate the clinical efficacy and safety of unrelated donor allogeneic bone marrow transplantation (URD-BMT) for the treatment of childhood leukemia. METHODS: Six patients with leukemia received URD-BMT. Two of them suffered from chronic myeloid leukemia (CML), 3 suffered from acute lymphocytic leukemia (ALL) and 1 suffered from acute promyelocytic leukemia (APL) (CR2). All cases were facilitated by Tzu Chi Marrow Donor Registry (TCTMDR). The high resolution DNA test for classIand II was carried out in HLA typing of all donor-receiver pairs. HLA allele matched in three cases, mismatched with one locus in two cases and with two loci in one case. All patients were prepared with cyclophosphamide (CY) 60 mg/kg/day for 2 days (total dose 120 mg/kg) and busulfan (Bu) 1 mg/kg x 4/day for 4 days (total dose 16 mg/kg). Mycophenolate mofetil (MMF), CsA and MTX were given to prevent acute graft-versus-host-disease (aGVHD). CsA of 3 mg/kg/d was continuously given by i.v. infusion, and then 6mg/kg/d by oral. The blood CsA concentration was 200 - 300 ng/ml. MTX was given at the dosage of 15 mg/m(2) on d 1 and 10 mg/m(2) on d 3, 6,9 or 11. MMF was given at the dosage of 0.25 - 0.5 g/d from day 0 to day 120. Prostaglandin E1 was given to prevent the hepatic veno-occlusive disease (VOD), Ganciclovir was used to prevent CMV infection until the CMV antigenemia became negative. RESULTS: Analysis of DNA short tandem repeats showed total engraftment of donor marrow after transplantation in all cases. The median time when granulocyte exceeded 0.5 x 10(9)/L was 14.5 (13 - 18) days, platelets exceeded 20 x 10(9)/L was 16 (14 - 23) days. The acute GVHD grade II-IV occurred in 2 of 6 (33.3%) patients. There were 3 cases with chronic GVHD and none of them developed with the extensive chronic GVHD. All patients were alive in disease-free situation now with median follow-up 412 (187 - 1338) days. CONCLUSION: URD-BMT is an effective method for the treatment of childhood leukemia.

Bone Marrow Transplantation↗

PubMed2004

[Cytomegalovirus infection of myeloma cell line KM3 and its effect on IL-6 mRNA expression in the cells].

OBJECTIVE: To investigate the infection of myeloma cell line KM3 by cytomegalovirus (CMV) as well as its effect on IL-6 mRNA in the cells. METHODS: RT-PCR assay was used to detect the mRNA expression of CMV immediate early gene (IE), glyceraldehyde phosphate dehydrogenase (GAPDH) and IL-6 of KM3 cells infected by 100-, 10-, 1-folds of median tissue culture infective dose (TCID(50)) of CMV. Flow cytometry was used to detect the expression of pp65 antigen. CMV particles were detected with electron microscope. RESULTS: KM3 cells infected by CMV could express IE mRNA as compared with the uninfected cells. CMV pp65 antigen positive cells were (5.58 +/- 1.55)% and (3.75 +/- 0.85)% respectively when infected by 100 and 10 TCID(50) of CMV, which were significantly higher than that of control group (P < 0.05). CMV particles could be seen in the infected cells. Expression of IL-6 mRNA was increased after the infection. CONCLUSION: CMV can infect myeloma cell line KM3 and replicate in the cells. CMV can increase the expression of IL-6 mRNA.

Cell Line, Tumor↗

PubMed2003

Unique physiological and pathogenic features of Leptospira interrogans revealed by whole-genome sequencing.

Leptospirosis is a widely spread disease of global concern. Infection causes flu-like episodes with frequent severe renal and hepatic damage, such as haemorrhage and jaundice. In more severe cases, massive pulmonary haemorrhages, including fatal sudden haemoptysis, can occur. Here we report the complete genomic sequence of a representative virulent serovar type strain (Lai) of Leptospira interrogans serogroup Icterohaemorrhagiae consisting of a 4.33-megabase large chromosome and a 359-kilobase small chromosome, with a total of 4,768 predicted genes. In terms of the genetic determinants of physiological characteristics, the facultatively parasitic L. interrogans differs extensively from two other strictly parasitic pathogenic spirochaetes, Treponema pallidum and Borrelia burgdorferi, although similarities exist in the genes that govern their unique morphological features. A comprehensive analysis of the L. interrogans genes for chemotaxis/motility and lipopolysaccharide synthesis provides a basis for in-depth studies of virulence and pathogenesis. The discovery of a series of genes possibly related to adhesion, invasion and the haematological changes that characterize leptospirosis has provided clues about how an environmental organism might evolve into an important human pathogen.

Bacterial Adhesion↗

PubMed2003

[Treatment of one case of adult chronic myelogenous leukemia by two units of unrelated umbilical cord blood transplantation].

To explore the hematopoietic reconstitution and transplantation-related complications of two units of unrelated umbilical cord blood combined transplantation for the treatment of adult hematologic malignancies, one adult patient with chronic myelogenous leukemia received two units of unrelated umbilical cord blood combined transplantation. The conditioning regimen was busulfan and cyclophosphamide (Bu-Cy). GVHD prophylaxis regimen consisted of mycophenolate mofetil (MMF), cyclosporine A (CsA) and methotrexate (MTX). The patient received total nucleated cells 4.63 x 10(7)/kg with CD34+ cells 8.34 x 10(5)/kg. Engraftment was documented by the analysis of short tandem repeat with polymerase chain reaction (STR-PCR). The results showed that the STR-PCR analysis for peripheral blood at day 31, 46 and 71 after transplantation suggested that one of two units of cord blood were completely engrafted. The ANC > 0.5 x 10(9)/L in the patient occurred at day 23, blood platelet counts > 20 x 10(9)/L at day 33 and > 50 x 10(9)/L at day 47. The Philadelphia chromosome and bcr/abl fusion gene of the patient also turned to negative after engraftment. Acute GVHD grade II occurred at day 13 and cured after treatment. It is concluded that umbilical cord blood can be used in adult hematopoietic stem cell transplantation. Two or more units umbilical cord blood combined transplantation might be the way to solve the problem of the low counts of nucleated cells when be used for adult.

Adult↗

PubMed2003

[Experimental study on olfactory evoked potential in rabbits].

OBJECTIVE: To observe olfactory evoked potential(OEPs) produced by electrical stimulation of the olfactory mucosa and to find out an objective way to appraise olfactory function. METHOD: A bipolar stimulus electrode was placed on the olfactory mucosa of adult health rabbits via anterior naris. Olfactory evoked potential was recorded at headtop after being given a 0.5-4.0 mA current to the mucosa. And we also investigated the effect of stimulus parameters and stimulus location to the wave form of OEPs. RESULT: Triphasic negative-positive-negative evoked potentials were recorded from the surface of the frontal head close to olfactory bulb. Latent period of three waves respectively was N(1)20.6 ms, P(1)33.5 ms, N(2)58.3 ms. CONCLUSION: In general, the OEPs were composed of triphasic negative-positive-negative complexes. The waveforms were stable and could be repeated well. Each parameter was useful for estimating the olfactory function.

Animals↗

PubMed2002

Sequence and analysis of rice chromosome 4.

Rice is the principal food for over half of the population of the world. With its genome size of 430 megabase pairs (Mb), the cultivated rice species Oryza sativa is a model plant for genome research. Here we report the sequence analysis of chromosome 4 of O. sativa, one of the first two rice chromosomes to be sequenced completely. The finished sequence spans 34.6 Mb and represents 97.3% of the chromosome. In addition, we report the longest known sequence for a plant centromere, a completely sequenced contig of 1.16 Mb corresponding to the centromeric region of chromosome 4. We predict 4,658 protein coding genes and 70 transfer RNA genes. A total of 1,681 predicted genes match available unique rice expressed sequence tags. Transposable elements have a pronounced bias towards the euchromatic regions, indicating a close correlation of their distributions to genes along the chromosome. Comparative genome analysis between cultivated rice subspecies shows that there is an overall syntenic relationship between the chromosomes and divergence at the level of single-nucleotide polymorphisms and insertions and deletions. By contrast, there is little conservation in gene order between rice and Arabidopsis.

Arabidopsis↗

PubMed2002

[Detection and analysis of bcl-1/IgH rearrangement in mantle cell lymphoma]

OBJECTIVE: To investigate the specificity and sensitivity of the PCR technique in the identification of bcl-1/IgH gene rearrangement in mantle cell lymphoma (MCL) and to characterize the bcl-1/IgH junction DNA sequences. METHODS: A semi-nested PCR method to amplify bcl-1/IgH gene rearrangement in DNA from fresh frozen lymphonode specimen was established. Twenty-eight cases of mantle cell lymphoma were analyzed for the presence of bcl-1/IgH gene rearrangement. The rearrangement products was cloned and sequenced to recognize the junction sequences, the breakpoints in the bcl-1 region, and J(H) gene involved in the rearrangement. RESULTS: A bcl-1/IgH gene rearrangement was detected in 17 out of 28 cases of MCL, while only 9 cases was detected with single step PCR method (X(2)=4.59, P<0.05). The rearrangement product varied in size between 74 to 162 base pairs, and the length of the junction sequences ranged from 6 to 24 base pairs. Ten different bcl-1 breakpoints were clustered within 65 base-pair spans, among which, 5 breakpoints (located at 430, 440, 451, 486 and 492) were never reported by other authors. The most common J(H) gene segments utilized in the translocation were J(H) 4 (8/18), then J(H)5 (3/18), J(H)6 (2/18), J(H)4/5 (2/18). J(H)1 2/18, and J(H)3 (1/18). CONCLUSION: These results indicate that the semi-nested PCR is a specific and sensitive method for the detection of bcl-1/IgH gene rearrangement in mantle cell lymphoma, which has implications for both the diagnosis and clinical management of mantle cell lymphoma. The recognization the potential mechanism of bcl-1/IgH gene rearrangement will help us to know the exact pathogenic machanisms of MCL.

Journal Article↗

PubMed2002

[Expression and clinical significance of anti-apoptosis gene, survivin, in acute leukemia].

OBJECTIVE: To explore the correlation between expression of surviving gene in acute leukemic cells and its clinical effects. METHODS: By using semi-quantitative reverse transcriptase polymerase chain reaction (RT-PCR) technique, surviving gene expression in 50 previously untreated acute leukemia (AL) patients was analysed. The apoptosis of primary leukemia cells cultured in vitro was assayed with terminal deoxyribonucleotidyl transferase mediated dUTP-biotin nick end labeling (TUNEL). RESULTS: Surviving gene expression levels in cells of AL patients at diagnosis were significantly higher than that in normal bone marrow mononuclear cells (MNCs) (82.0% vs 33.3%, P < 0.05). The expression level was higher in ALL cells than in ANLL cells (89.5% vs 75.0%). Among 22 cases of ANLL, bone marrow remission (BMR) rate was higher in surviving gene negative expression cells from patients accepted a course of chemotherapy than in positive expression cells (83.3% vs 25.0%, P = 0.023). Among 13 ANLL patients received a course of HA regimen chemotherapy, the BMR was higher in patients surviving mRNA negative expression cells than in positive cells (100.0% vs 27.3%). Patients with surviving/beta-actin ratio>0.6 attained lower BMR. CONCLUSION: Higher expression level of surviving mRNA in AL cells may be one of the reasons that leukemic cells are insensitive to chemotherapy.

Adolescent↗

PubMed2002

[Relativities between lattice changes and the function of dissolution improvement of poorly soluble drug silymarin based upon PEG 6,000 solid dispersion system].

AIM: To investigate the lattice mechanisms involved in the increased dissolution effect of polyethylene glycol (PEG 6,000) dispersion system on poorly soluble drug silymarin (SILY). METHODS: Fusion method was used to prepare the solid dispersions of SILY with PEG 6,000. Evaluation of the improvement of dissolution was performed with dissolution studies in vitro. X-ray powder diffraction combined with diffraction peak pattern-fitting procedure were applied to quantitatively analyze the changes of lattice parameters. The interaction of SILY and PEG 6,000 was also determined with Fourier transform-infrared (FT-IR) spectroscopy. RESULTS: The dissolution rate of SILY was considerably increased when formulated in solid dispersion of PEG 6,000 as compared to pure SILY. The datum from the X-ray diffraction showed the changes in the lattic spacings and particular diffraction peaks (position and the intensity) of PEG 6,000 and SILY. These could explain the increased rate of SILY released from solid dispersion system. The information of FT-IR spectroscopy showed the absence of well-defined drug-polymer interaction. CONCLUSION: The dissolution improvement of poorly soluble SILY from solid dispersion of PEG 6,000 can be illuminated by the changes of the lattice parameters of PEG 6,000 and the drug.

Chemistry, Pharmaceutical↗