Biomedical subjects

Li-Jian Yang

Publications and source records attributed to Li-Jian Yang.

10 recordsLinked to original sources

PubMed2006

A mesoscopic stochastic mechanism of cytosolic calcium oscillations.

Based on a model of intracellular calcium (Ca(2+)) oscillation with self-modulation of inositol 1,4,5-trisphosphate signal, the mesoscopic stochastic differential equations for the intracellular Ca(2+) oscillations are theoretically derived by using the chemical Langevin equation method. The effects of the finite biochemical reaction molecule number on both simple and complex cytosolic Ca(2+) oscillations are numerically studied. In the case of simple intracellular Ca(2+) oscillation, it is found that, with the increase of molecule number, the coherence resonance or autonomous resonance phenomena can occur for some external stimulation parameter values. In the cases of complex cytosolic Ca(2+) oscillations, each extremum of concentration of cytosolic Ca(2+) oscillations corresponds to a peak in the histogram of Ca(2+) concentration, and the most probability appeared during the bursting plateau level for bursting, but at the largest minimum of Ca(2+) concentration for chaos. For quasi-periodicity, however, there are only two peaks in the histogram of Ca(2+) concentration, and the most probability is located at low concentration state.

Calcium↗

PubMed2005

[Expressions of transcription factor GATA-1 and GATA-2 genes in bone marrow stromal cells from patients with leukemia].

In order to investigate expressions of transcription factor GATA-1 and GATA-2 genes in the bone marrow stromal cells (BMSCs) from patients with leukemia or normal controls, bone marrow stromal cells from 34 normal cases and 42 cases with leukemia were cultured long-term in vitro. Nonadherent cells (bone marrow hematopoietic cells) and amplified adherent cells (BMSC) were collected separately. Expressions of GATA-1 and GATA-2 genes were analyzed by using RT-PCR-ELISA; the semi-quantitative expression levels of GATA genes in the BMSCs from patients with leukemia were compared with normal controls. The results showed that expressions of GATA-1 and GATA-2 genes could be detected in the BMSCs and the bone marrow hematopoietic cells from both normal controls and the cases of leukemia. The expression ratio of GATA-1 in the BMSCs from acute lymphocytic leukemia (ALL) (85.7%) was similar to the normal controls (88.2%), whereas the expression ratios in BMSCs from acute myelocytic leukemia (AML) (55.6%) and chronic myelocytic leukemia (CML) (41.2%) were significant lower than the normal controls (P < 0.05). The rank of expression level of GATA-1 gene in the BMSCs was "ALL>AML>normal>CML". There was no difference in the expression level of GATA-2 gene within the BMSCs from normal controls and patients with leukemia. The ranks of expression levels of GATA-1 and GATA-2 genes in bone marrow hematopoietic cells were "AML>normal>ALL>CML" and "AML>CML>ALL>normal". The dominant expression of GATA-2 gene was found in the BMSCs from AML, CML or normal controls. It is inferred that the expressions of GATA-1 and GATA-2 genes in the BMSCs of normal controls and patients with leukemia may influence the regulation of hematopoiesis in the bone marrow stroma and it is worthy of further study to explore their roles in pathogenesis and development of leukemia.

Adolescent↗

PubMed2005

[Significant decrease of recent thymic output function in patients with severe benzene intoxication].

The aim of the present study was to investigate the level of T-cell receptor excision DNA circles (TREC) in peripheral blood mononuclear cells (PBMNC) of patients with severe benzene poison, thereby to evaluate the content of naive T cells and the recent thymic output function. Quantitative detection of TREC in DNA of PBMNCs from 16 normal individuals and 8 cases with severe benzene poison was preformed by real-time PCR using TaqMan technique. The results showed that TREC level was 6.69 +/- 4.79/1 000 PBMNCs in normal individuals, however, significant decrease was shown in patients with severe benzene poison (1.03 +/- 0.44/1 000 PBMNCs, P < 0.01). The TREC level was persistently low in period of benzene poisoning, even if peripheral blood cell counts were at normal levels. In conclusion, the recent thymic output function is remarkably decreased in patients with severe benzene intoxication, that may obviously damage the T cell immune function.

Adult↗

PubMed2004

[Expression of SCL gene in bone marrow stromal cells from patients with leukemia].

In order to investigate expression of SCL (stem cell leukemia) gene in bone marrow stromal cells (BMSC) and bone marrow cells from patients with leukemia and normal individuals, bone marrow mononuclear cells from AML (18 cases), CML (17 cases), ALL (7 cases) and normal individuals (33 cases) were cultured long-term in vitro. Nonadherent cells (hematopoietic cells) and amplified adherent cells (BMSC) were collected respectively. RT-PCR-ELISA assay was then performed to detect expression of SCL gene. The expression ratio of SCL gene were analyzed and its expression level was normalized by beta(2)M gene acting as an internal reference for the purpose of semi-quantitative analysis. The results indicated that the expression ratio of SCL gene was lower in BMSC from AML (27.8%) and CML (11.8%) than that in normal controls (69.7%, P < 0.05), while was higher in the nonadherent cells from CML (64.3%) than that in its corresponding BMSC (P < 0.05). Semi-quantitative analysis showed that SCL gene expression level in nonadherent cells from AML was higher than that in its corresponding BMSC (P < 0.05). In conclusion, the low-level expression state of SCL gene in BMSC from patients with AML and CML may be involved in the abnormal regulation of hematopoiesis in myelocytic leukemia.

Adolescent↗

PubMed2003

[Comparison of the clonal expansion of TCR Vbeta T cells in patients with acute promyelocytic leukemia in vivo and in vitro].

In order to analyze the distribution and clonal expansion of TCR Vbeta subfamily T cells in patients with acute promyelocytic leukemia (APL) in vivo and in vitro after T cell culture, the peripheral blood mononuclear cells from 3 APL patients were expanded by rhIL-2 and anti-CD3 antibody using liquid T lymphocytes culture technique. The complementary determining region 3 (CDR3) of TCR beta with variable region genes was amplified in T cells from 3 APL cases before and after T cell culture by using RT-PCR. The positive products were further analyzed to identify the clonality of T cells by genescan. The results showed that only a part of 24 Vbeta subfamilies was detected in T cells from the patients, and some Vbeta subfamily T cells could be identified after T cells culture. The clonal expansion T cells in some TCR Vbeta subfamilies could be found in all patients. The similar oligoclonal expansion of Vbeta1, Vbeta3, Vbeta7, Vbeta16 and Vbeta20 T cells was detected in two cases at different time points after T cell culture. It is concluded that the restricted expression of TCR Vbeta subfamily in T cells from patients might be the common feature in leukemia. Some Vbeta subfamily T cells could be induced after T cells culture in vitro. The continual clonal expansion of TCR Vbeta subfamily T cells at different time points after T cells culture could be a specific immune response of patients T cells related to the specific APL cell associated antigen.

Humans↗

PubMed2003

[Estimate of Recent Thymic Output Function - Quantification of T Cell Receptor Rearrangement Excision Circles (TRECs)].

For a long time, thymic function could not be monitored, as a consequence of the absence of adequate technology to detect recent thymic emigrants from naive T cells. T cell differentiation in the thymus is characterized by T cell receptor (TCR) rearrangement. During the rearrangement of TCRalpha gene segments, the deltaRec and psiJalpha rearrange to each other to delete the TCRdelta gene and form an extrachromosomal DNA circles, referred to as signal joint T cell receptor excision DNA circles (sjTRECs) or TRECs. TRECs are assumed to have a high stability, they can not multiply and consequently are diluted during T cell proliferation. It was recently suggested that quantitative detection of TRECs would allow for direct measurement of thymic output. In this review TRECs quantification is a powerful method to evaluate the thymic output function in both health and disease, including hematopoietic stem cell transplantation, hematopoietic malignancies, HIV infection and autoimmune disease, and so on is described.

Animals↗

PubMed2002

[Study on clonal proliferation of TCR Vbeta subfamily T cells induced by AML-M(2a) cells in vivo and in vitro].

To observe the expression and clonal expansion of TCR Vbeta subfamily T cells induced by AML-M(2a) cells in vivo and in vitro, complementary determining region 3 (CDR3) of TCR beta with variable region genes was amplified by using RT-PCR in both peripheral blood mononuclear cells (PBMNC) and T cells from mixed lymphocyte and tumor culture (MLTC) from four AML-M(2a) patients. The positive products were further analyzed to identify the clonality of T cells by genescan. The results showed that the similarity distribution of TCR Vbeta subfamily T cells was found Vbeta in PBMNC and MLTC. One or two clonality expansions of T cells could be found in predominant TCR Vbeta subfamily T cells induced by A ML-M2a cells from 3 cases in vivo and in vitro. It was concluded that clonal expansion of TCR Vbeta subfamily T cells stimulated selectively by AML-M(2a) cells may be a specific immune response of patient's T cells to AML-M(2a) cells associated antigen. The clonal proliferation of TCR Vbeta subfamily T cells were affected somewhat by environmental difference in vivo and in vitro.

Gene Rearrangement, T-Lymphocyte↗

PubMed2002

[Analysis of selected usage and clonal expansion of TCR Vbeta repertoire of peripheral blood T cells in patients with non-Hodgkin's lymphoma].

To investigate the distribution and clonal expansion of TCR Vbeta subfamily T cells in patients with B-NHL and T-NHL, the CDR3 of TCR Vbeta 24 subfamily genes was amplified in peripheral blood mononuclear cells from 4 cases with B-NHL and 2 cases with T-NHL using RT-PCR, and to observe the usage of TCR Vbeta repertoire, the PCR products were further labeled with fluorescence and analyzed by genescan technique for the CDR3 size, to evaluating clonality of the detectable TCR Vbeta T cells. The results indicated that only selected expression of 6-12 Vbeta subfamily T cells could be identified in the 6 cases with NHL, and Vbeta1, Vbeta8, Vbeta13 and Vbeta19 were expressed in all samples, Vbeta2 and Vbeta16 could be found in 5 samples, whereas Vbeta4-6, Vbeta10-12, Vbeta15, Vbeta17-18, Vbeta20 and Vbeta22-23 were absent in all samples. Genescan analysis showed that clonal expansion of T cells could be found in 1-3 Vbeta subfamilies from 2 cases with B-NHL and 1 case with T-NHL. In conclusions, the similar selected usage of TCR Vbeta subfamily T cells could be found in peripheral blood from patients with B and T NHL, clonal expansion of T cells which were considered to be related to lymphoma cell antigen could be detected in a part of patients with B or T NHL.

Cell Line↗

PubMed2002

[The distribution feature of TCR Vbeta repertoire in peripheral blood T cells from patients with Ph(+) and Ph(-) CML].

To investigate the T cell distribution characters of TCR Vbeta repertoire in Ph(+) and Ph(-) CML. The 24 subfamilies of the TCR Vbeta genes were amplified in peripheral blood T cells from 13 patients with CML (Ph+ b3a2, 5 cases; Ph+ b2a2, 5 cases; Ph(-), 3 cases) by RT-PCR, to analyze the usage of Vbeta subfamilies in different CML patients. The results showed that the expression pattern of Vbeta repertoire was different in normal individuals and in patients with CML which only have part of Vbeta subfamily T cells. 4 - 16 (mean 10.2) Vbeta subfamily T cells were detected in the Ph+ b3a2 CML, 8 - 11 (mean 8.8) Vbeta subfamily T cells in the Ph(+) b2a2 CML and 5 - 6 (mean 5.7) in Ph(-) CML. Moreover, the expression of Vbeta subfamily T cells was different among these three types CML.Vbeta10 and Vbeta16 were detected in the all cases with Ph(+) b3a2 and Ph(+) b2a2 CML, whereas Vbeta9 and Vbeta22 could be found in the most cases with Ph(+) b3a2 CML or Vbeta24 and Vbeta8 in Ph(+) b2a2 CML. In patients with Ph(-) CML, Vbeta24 were detected in all samples, and Vbeta9, Vbeta10, Vbeta13 and Vbeta22 were found in the most cases. The results suggest that skew distribution of TCR Vbeta subfamily T cells was existed in peripheral blood of Ph(+) and Ph(-) CML patients. The selected usage of TCR Vbeta is different in various types of CML patients. It may relate to difference of CML cells associated antigen and individual special immunity reaction.

Adolescent↗

PubMed2002

[The feature of TCR V alpha40 with Jdelta1, Ddelta3 or psiJalpha gene rearrrangements in T cells].

The rearrangement segments of TCR Valpha40 gene with Jdelta1, Ddelta3 or psi Jalpha were amplified in genomic DNA from peripheral blood mononuclear cells of 10 normal subjects, sorted CD3(+) cells from peripheral blood of 4 cases and thymocytes from 7 cases, by using nested PCR. Different amounts of DNA from all samples were amplified to estimate the frequency of Valpha40 gene rearrangements. The results indicated that the rearrangements of TCR Valpha40 gene with Jdelta1, Ddelta3 or psi Jalpha could be found respectively in the most samples of peripheral blood T cells or thymocytes. The frequencies of Valpha40 rearrangements were different in peripheral blood T cells and thymocytes by analysis of PCR with different amounts DNA. It is concluded that the TCR V alpha40-psi Jalpha was the most frequent rearrangement in mature and immature T cells, whereas TCR Valpha40-Ddelta3 was more frequently rearranged in immature T cells

Gene Rearrangement↗