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Biomedical subjects

Li Ma

Publications and source records attributed to Li Ma.

At least 55 records · Page 3Linked to original sources
PubMed2006

[Detection of fusion genes associated with specific translocations in acute leukemia patients with normal karyotypes by using multiplex RT-PCR].

This study was aimed to explore the usefulness of multiplex reverse transcription-polymerase chain reaction (multiplex RT-PCR) in detection of fusion genes associated with specific translocations in acute leukemia (AL) patients with normal karyotypes. 37 AL patients with normal karyotypes were analyzed by multiplex RT-PCR. The results showed that 4 types of fusion genes such as PML/RARA, AML1/ETO, CBFbeta/MYH11, BCR/ABL were detected in 8 (21.6%) patients by multiplex RT-PCR. In conclusion, multiplex RT-PCR is useful in detection of fusion genes associated with specific translocations in acute leukemia (AL) with normal karyotypes and it would refine the karyotype analysis. When the normal karyotypes were detected in acute leukemia patients by conventional cytogenetic method, the multiplex RT-PCR should be performed for them.

Acute Disease↗
PubMed2006

[Homology analysis of the epidemiological strains of meticillin-resistant Staphylococcus aureus and the strains isolated from the nasal fossa of the medical staff and inpatients].

OBJECTIVE: To investigate the relation between the epidemiological strains of meticillin-resistant Staphylococcus aureus (MRSA) and the strains isolated from the nasal fossa of the medical staff and inpatients. METHODS: The MRSA strains were isolated from the nasal fossa of the medical staff and inpatients in the Department of Neurosurgery. The genes of the isolated strains were amplified by randomly amplified polymorphic DNA (RAPD) assay. RESULTS: Three and 12 MRSA strains were isolated from the nasal fossa of the medical staff and patients who were hospitalized for more than 1 week, respectively, and RAPD assay revealed high homology between the isolated strains. CONCLUSION: Cross infection can be present between the medical staff, inpatients, and the infected patients.

China↗
PubMed2006

[Pathological changes of the blood vessels in rabbit femoral head with glucocorticoid-induced necrosis].

OBJECTIVE: To observe the pathological changes in the blood vessels in rabbit femoral head with glucocorticoid-induced necrosis and investigate the pathogenesis of glucocorticoid-induced osteonecrosis. METHODS: Twenty New Zealand white rabbits were randomly divided into two groups, namely group A. which was injected with horse serum and prednisone and group B as the control group. Chinese ink was injected into the femoral cavity of the rabbits to observe the blood vessels in the femoral head under optical microscope and the femoral head was examined histopathologically. RESULTS: Compared with the normal control group, the rabbits in group A had significantly decreased number of perfused vessels, which was featured by defective perfusion, osteocytie pyknosis or necrosis, increase of empty ostoocyte lacunae and fat cells, decrease of hematopoietic tissue, and blood vessel occlusion. CONCLUSION: Vascular occlusion and vasculitis due to glucocorticoid treatment may cause avascular necrosis of the femoral head.

Animals↗
PubMed2006

[Clinicopathologic features of gallbladder adenocarcinoma with marked stromal fibrosis--a report of 19 cases].

BACKGROUND & OBJECTIVE: Macropathologic types of gallbladder cancer are mostly polyp type, intumescent type, and cauliflower form lump. Its histological types include well or poorly differentiated adenocarcinoma, mucinous adenocarcinoma, and undifferentiated cancer. This research was to explore the clinicopathologic features of gallbladder adenocarcinoma with marked stromal fibrosis. METHODS: Pathology of 19 cases of gallbladder adenocarcinoma with marked stromal fibrosis was observed using a light microscopy and SP immunohistochemistry. Clinicopathologic features of 19 patients were analyzed. RESULTS: Most of the patients had long-term history of cholecystitis gallbladder calculus. B ultrasound showed that the gallbladder wall was irregularly thickened or presented nodosity. Observed with naked eyes, gallbladder adenocarcinoma with marked stromal fibrosis did not form cancer nodule and extrude into the gallbladder lumen, the gallbladder wall showed regional thickening, a few cases showed diffuse irregular thickening. Observed under a light microscope, the adenocarcinoma cells were mostly arranged as single layers, seldom arranged as multiple layers, and formed adenoid structures with different sizes, various shapes, and irregular arrangement; the nuclei were heterogenic with haryomitosis presented in a few cases; inflammatory cells were infiltrated in hyperplastic fibrous connective tissue of some cases. According to immune phenotyping, CK (AE1/AE3), CK (AE1), CK7 (OV-TL12/30), CK8 (C51), CK18 (Dc-10), CK19 (RCK108), and EMA (Mc-5) showed strong expression, CEA (COL-1), CK20 (Ks20. 4), and MUC-5AC (CLH2) showed moderate expression, and MUC-2 (B306. 1) showed weak expression; CK17 (E3) showed focal expression. CONCLUSIONS: The clinical manifestation, macropathologic type, histological characteristics of gallbladder adenocarcinoma with stromal fibrosis are different from other types of adenocarcinoma. Its genesis may be related to chronic cholecystitis: long-term inflammation causes regional hyperplasia and heterogeneity of the gland body, lead to focal or regional thickening of the gallbladder wall, and result in gallbladder adenocarcinoma with stromal fibrosis finally.

Adenocarcinoma↗
PubMed2006

Evaluation of efficacy and safety of diacerein in knee osteoarthritis in Chinese patients.

OBJECTIVE: To evaluate the efficacy and safety of diacerein in patients with knee osteoarthritis (OA). METHODS: A total of 223 patients satisfying the American College of Rheumatology criteria for knee OA were chosen for this 17-week, randomized, double-dummy, diclofenac sodium-controlled trial, with diacerein dosage of 100 mg/d and diclofenac sodium of 75mg/d. Efficacy and safety of both drugs were evaluated. RESULTS: Totally 106 patients in the diacerein group and 107 patients in the diclofenac group were considered qualified for the evaluation. After 12 weeks of treatment, the total effective rates of patients/physicians' overall assessment in diacerein and diclofenac groups were 65.4%/61.6% and 61.2%/61.2%, respectively (P > 0.05). The primary efficacy parameter [visual analog scale (VAS) assessment of pain on 20 metres walking] and the secondary efficacy parameters [tenderness on palpation, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and 36-item Short-Form (SF-36) Health Survey] significantly improved compared with baseline in both groups (P < 0.05). In the follow-up period, there were no obvious changes in above parameters in diacerein group. However, in diclofenac group, pain on 20 metres walking, tenderness on palpation, and WOMAC became aggravated after withdrawing the drug for 4 weeks (P < 0.05). Moreover, the consumption of paracetamol was significantly lower in diacerein group than in diclofenac group during follow-up (P < 0. 001). The incidences of related adverse events were 35.7% in diacerein and 45.1% in diclofenac group, respectively. Mild-to-moderate gastrointestinal disorders were the most frequent adverse events. CONCLUSIONS: Diacerein is as effective as diclofenac sodium in treating patients with knee OA. Furthermore, it has better extended effect and a good safety profile. It is generally well tolerated and has no severe adverse effect.

Adult↗
PubMed2006

[Effects of T cell receptor gene rearrangement on BV CDR3 in Jurkat cells].

OBJECTIVE: To investigate the effects of T cell receptor (TCR) BD2-BJ2 gene rearrangement on the complementary-determining region (CDR) 3 of TCR beta chain (TCR BV CDR3) in Jurkat cells. METHODS: TCR BV gene subfamilies were detected by RT-PCR in Jurkat cells during proliferation and after induction with non-specific T cell activators and SEA, respectively. To determine the clonality of TCR BV subfamilies and the lengths of CDR3, the PCR products were analyzed by TCR GeneScan technique, and the sequences of CDR3 were further analyzed by DNA sequencer. RESULTS: No new TCR BV subfamilies were found in Jurkat cells, a monoclonal BV8(+)cell line, either during cell proliferation or after stimulation with different treatments, nor were any differences found in CDR3 size or sequences. CONCLUSION: TCR BD2-BJ2 rearrangement in Jurkat cells may not play a role in modification of TCR BV CDR3 domains or the consequent antigen immunorecognition of BV CDR3, but the possibility of TCR modification can not be excluded.

Amino Acid Sequence↗
PubMed2006

[The value of multiplex fluorescence in situ hybridization in the detection of complex karyotypic abnormalities of acute myeloid leukemia].

OBJECTIVE: To investigate the value of multiplex fluorescence in situ hybridization (FISH) in the detection of complex karyotypic abnormalities of acute myeloid leukemia (AML). METHODS: Multiplex FISH was used in combination with conventional cytogenetics (CC) and interphase FISH to study 14 cases of AML with complex karyotypic abnormalities. RESULTS: In the 14 cases of AML studied, conventional cytogenetics detected 23 numerical and 56 structural chromosome abnormalities. Among them 4 gained whole chromosome and 4 lost whole chromosome which were confirmed by multiplex FISH. Twelve chromosome losses detected by CC were revised as derivative chromosomes resulted from various structural aberrations, and 26 derivative and 19 marker chromosomes were characterized precisely by multiplex FISH. Most of them were resulted from unbalanced translocations, including 2 complex 8; 21 translocations, which have not been reported previously: t (8; 21), der (8) t (8; 21) (8pter --> 8q22::21q22 --> 21qter), der (21) t (8; 21; 8) (8qter --> 8q22:: 21p13 --> 21q22::8q22 --> 8qter) and t (21; 8; 18; 1), der (8) t (8; 21) (8pter --> 8q22:: 21q22 --> 21qter), der (21) t (21; 8; 18; 1) (21p13 --> 21q22?::8q22 --> 8q24 ?:: 18??::1q??q??). The complex karyotypic abnormalities involved nearly all chromosomes, of which the chromosomes 17, 7 and 5 were more involved than the rest. CONCLUSION: Multiplex FISH in combination with conventional cytogenetics may characterize the complex chromosomal abnormalities more precisely. Introduction of this technique to the study of AML with complex chromosomal abnormalities is warranted.

Acute Disease↗
PubMed2006

[Role of caspase-8 and DR5 in TRAIL-induced apoptosis of neuroblastoma cells].

OBJECTIVE: Tumor necrosis factor related apoptosis inducing ligand (TRAIL) induces cell death in a variety of tumors but not in normal cells. TRAILdouble ended arrow-resistance of most neuroblastoma (NB) cell lines is related to the loss of caspase-8 expression and the expression and distribution of membrane TRAIL-receptors. This study investigated the role of caspase-8 and DR5 in TRAIL-induced apoptosis of NB cell line SKNDZ. METHODS: The expression of caspase-8 mRNA was detected by RT-PCR. The expression of DR5 protein was detected by Western Blot analysis. The effects of TRAIL, IFNgamma +TRAIL, chemotherapeutic agent (adriamycin or etoposide) + TRAIL, and chemotherapeutic agent +TRAIL+ IFNgamma on the growth and apoptosis of SKNDZ cells were detected by MTT assay and flow cytometry. RESULTS: caspase-8 was not expressed in SKNDZ cells but IFNgamma treatment resulted in an increase of caspase-8 expression. Expression of DR5 protein was not detected in SKNDZ cells but an increased DR5 protein expression was found after treatment with adriamycin or etoposide. The SKNDZ cells expressing caspase-8 were not sensitive to TRAIL but those SKNDZ cells expressing both caspase-8 and DR5 were sensitive. The early apoptosis rates of the adriamycin /etoposide + IFNgamma+TRAIL groups [(17.9 +/- 3.6)%, (14.8 +/- 3.3)%] were higher than that of the IFNgamma+TRAIL group [(3.9 +/- 1.2)% ](F=26.233, P < 0.01). CONCLUSIONS: SKNDZ cells expressing both caspase-8 and DR5 restored the TRAIL sensitivity. Caspase-8 and DR5 play a key role in TRAIL-induced apoptosis of NB cells.

Apoptosis↗
PubMed2006

Refolding and purification of recombinant human VEGF-121 expressed as inclusion bodies in Escherichia coli.

Vascular endothelial growth factor 121 (VEGF(121)) was expressed as inclusion bodies by recombinant Escherichia coli. High concentrations of both biomass (46 g dry cell/L) and VEGF(121) inclusion bodies (4.5 g/L) were obtained by applying a high-cell-density culture. After the inclusion bodies were washed and dissolved, VEGF(121) was refolded at 0.2 mg/ml by ultrafiltration in refolding buffer with a yield of 81%. Renatured VEGF(121) was purified by anion chromatography and Sephacry S-100 chromatography with purity higher than 95% and final purification yield of 31%. The purified VEGF(121) could stimulate the proliferation of human umbilical vein endothelial cells as demonstrated by a biological activity assay.

Cell Line↗
PubMed2006

[Expression, purification and identification of mouse granulocyte-macrophage colony-stimulating factor].

OBJECTIVE: To construct mouse granulocyte-macrophage colony-stimulating factor (mGM-CSF) expression vector and express, purify and refold mGM-CSF protein. METHOD: Based on previously constructed fusion protein hIL-2/mGM-CSF expression vector, pET-11c/mGM-CSF expression vector was constructed routinely and transformed into BL21 (DE3). The inclusion body protein was washed with our patented method and refolded with renaturation buffer containing low-concentration guanidinium chloride (Gu.Cl). The refolded protein was purified with affinity chromatography. RESULTS: pET-11c/mGM-CSF vector was constructed successfully. The host bacteria was cultured in TH broth and induced with 0.1 mmol/L IPTG at 32 degrees C, which resulted in the expression level of 60.6%. The best refolding effect was achieved with the renaturation media containing glutathione and 1.5 mol/L Gu.HCl. After purification with affinity chromatography, the purity of the target mGM-CSF protein reached 95% with activity of 5x10(6) U/mg. CONCLUSION: Engineered bacteria BL21/pET- 11c/mGM-CSF with efficient mGM-CSF expression and laboratory scale renaturation and purification of mGM-CSF have been established, which facilitates further researches into the anti-tumor function of the dendritic cells and GM-CSF in vivo.

Animals↗
PubMed2006

[Complementarity-determining region 3 analysis of T cell receptor beta chain variable region in peripheral blood mononuclear cells of patients with systemic lupus erythematosus].

OBJECTIVE: To analyze the drift of the complementarity-determining region 3 (CDR3) of T cell receptor (TCR) beta chain variable region (TCR BV) in peripheral blood mononuclear cells (PBMCs) of patients with systemic lupus erythematosus. METHODS: Immunoscope spectratyping techniques was used to analyze the distribution of TCRbeta chain CDR3 in 5 normal blood donors and the dominant CDR3 in the PBMCs in 5 SLE patients. Sequence analysis of the CDR3 region in monoclonal or oligoclonal T cells was performed. RESULTS: The spectratypes of TCR BV gene CDR3 region showed Gaussian distribution in the 5 normal blood donors. The 5 SLE patients, however, displayed anomalous proliferation and oligoclonal expansion of the T cells was observed in different TCR BV families with different CDR3 sequences. CONCLUSION: Noticeable drift of TCRbeta chain CDR3 can be seen in active SLE, indicating possible association of selective expression of TCR with immune pathogenesis in SLE. Determination of specific TCR CDR3 sequence provides a new means for studying the pathogenesis and personalized treatment of SLE.

Amino Acid Sequence↗
PubMed2006

[Determination of total organic acids and salicylic acid in extract of Radix isatidis].

OBJECTIVE: To develop a quantitative method for determination of the total organic acids and salicyclic acid in the extract of Radix Isatidis. METHOD: The total organic acids were determined by acid-base titration and the salicylic acid was determined by HPLC. RESULT: It was shown that contents of total organic acids and salicylic acid in the extract of Radix Isatidis were 13.0% and 0.22%, respectively. CONCLUSION: The method can control the quality of this extract effectively and accurately.

Carboxylic Acids↗
PubMed2006

[T cell receptor gene recombination in human T-cell leukemia cell line jurkat].

BACKGROUND & OBJECTIVE: Recently, recombination activating gene (RAG)-mediated transposition has been found to contribute to chromosomal translocation and may be related to the occurrence of lymphoid malignancy; however, the underlying mechanism is unclear. Our previous study showed a co-expression of RAG1 and RAG2 in a human T-cell leukemia cell line Jurkat, which represents a mature stage of T cell development, and that the mRNA levels could be regulated by T cell activators. This study was to determine RAGs-mediated T cell receptor(TCR) gene recombination in Jurkat cells, and thus to provide a new thoughtway for studying the correlations of TCR gene recombination to lymphoid malignancy. METHODS: TCR Dbeta-Jbeta signal joint T-cell receptor excision DNA circles (sjTRECs) were determined by nested and semi-nested polymerase chain reaction (PCR). Double-strand DNA breaks at recombination signal sequences (RSSs) in the TCR beta chain locus were detected by ligation-mediated polymerase chain reaction (LM-PCR). TdT and Ku70/Ku80 were detected by reverse transcription-polymerase chain reaction (RT-PCR). RESULTS: Characteristics of junctional diversity of Dbeta2-Jbeta2 sjTRECs and ds RSS breaks associated with Dbeta2 5'-site and Dbeta2 3'-site were detected in DNA of Jurkat cells. TdT and Ku70/Ku80 were also detected. CONCLUSION: There is an ongoing TCR gene recombination in Jurkat cells. Jurkat may be used as an ideal cell line model for studying the correlation of TCR gene recombination to lymphoid malignancy.

Antigens, Nuclear↗
PubMed2005

Potent block of inactivation-deficient Na+ channels by n-3 polyunsaturated fatty acids.

A voltage-gated, small, persistent Na(+) current (I(Na)) has been shown in mammalian cardiomyocytes. Hypoxia potentiates the persistent I(Na) that may cause arrhythmias. In the present study, we investigated the effects of n-3 polyunsaturated fatty acids (PUFAs) on I(Na) in HEK-293t cells transfected with an inactivation-deficient mutant (L409C/A410W) of the alpha-subunit (hH1(alpha)) of human cardiac Na(+) channels (hNav1.5) plus beta(1)-subunits. Extracellular application of 5 microM eicosapentaenoic acid (EPA; C20:5n-3) significantly inhibited I(Na). The late portion of I(Na) (I(Na late), measured near the end of each pulse) was almost completely suppressed. I(Na) returned to the pretreated level after washout of EPA. The inhibitory effect of EPA on I(Na) was concentration dependent, with IC(50) values of 4.0 +/- 0.4 microM for I(Na) peak (I(Na peak)) and 0.9 +/- 0.1 microM for I(Na late). EPA shifted the steady-state inactivation of I(Na peak) by -19 mV in the hyperpolarizing direction. EPA accelerated the process of resting inactivation of the mutant channel and delayed the recovery of the mutated Na(+) channel from resting inactivation. Other polyunsaturated fatty acids, docosahexaenoic acid, linolenic acid, arachidonic acid, and linoleic acid, all at 5 microM concentration, also significantly inhibited I(Na). In contrast, the monounsaturated fatty acid oleic acid or the saturated fatty acids stearic acid and palmitic acid at 5 microM concentration had no effect on I(Na). Our data demonstrate that the double mutations at the 409 and 410 sites in the D1-S6 region of hH1(alpha) induce inactivation-deficient I(Na) and that n-3 PUFAs inhibit mutant I(Na).

Cell Line↗
PubMed2005

Genetic analysis of Pten and Tsc2 functional interactions in the mouse reveals asymmetrical haploinsufficiency in tumor suppression.

The role of tumor suppressor haploinsufficiency in oncogenesis is still poorly understood. The PTEN and TSC2 tumor suppressors function to antagonize mTOR (mammalian target of rapamycin) activation by Akt; hence, compound heterozygous inactivation of Pten and Tsc2 in the mouse may in principle exacerbate the tumor phenotypes observed in the single mutants in a reciprocal manner. In contrast, we found that while Tsc2 heterozygosity unmasks Pten haploinsufficiency in growth and tumor suppression, tumorigenesis in Tsc2+/- mutants is surprisingly not accelerated by Pten heterozygosity, even though mTOR activation is cooperatively enhanced by compound Pten/Tsc2 heterozygosity. We show that the wild-type alleles of both Pten and Tsc2 are retained in prostate tumors from both Pten+/- and Pten+/-Tsc2+/- mice, whereas TSC-related tumor lesions are invariably associated with Tsc2 loss of heterozygosity (LOH) in both Tsc2+/- and Pten+/-Tsc2+/- mice. These findings demonstrate that inactivation of TSC2 is epistatic to PTEN in the control of tumor initiation and progression and, importantly, that both Pten and Tsc2 are haploinsufficient for suppression of tumorigenesis initiated by Pten heterozygosity, while neither Pten nor Tsc2 is haploinsufficient for repression of carcinogenesis arising from Tsc2 heterozygosity, providing a rationale for the differential cancer susceptibility of the two human conditions associated with PTEN or TSC2 heterozygous mutations.

Animals↗
PubMed2005

Adenine nucleotide regulation in pancreatic beta-cells: modeling of ATP/ADP-Ca2+ interactions.

Glucose metabolism stimulates insulin secretion in pancreatic beta-cells. A consequence of metabolism is an increase in the ratio of ATP to ADP ([ATP]/[ADP]) that contributes to depolarization of the plasma membrane via inhibition of ATP-sensitive K+ (K(ATP)) channels. The subsequent activation of calcium channels and increased intracellular calcium leads to insulin exocytosis. Here we evaluate new data and review the literature on nucleotide pool regulation to determine the utility and predictive value of a new mathematical model of ion and metabolic flux regulation in beta-cells. The model relates glucose consumption, nucleotide pool concentration, respiration, Ca2+ flux, and K(ATP) channel activity. The results support the hypothesis that beta-cells maintain a relatively high [ATP]/[ADP] value even in low glucose and that dramatically decreased free ADP with only modestly increased ATP follows from glucose metabolism. We suggest that the mechanism in beta-cells that leads to this result can simply involve keeping the total adenine nucleotide concentration unchanged during a glucose elevation if a high [ATP]/[ADP] ratio exits even at low glucose levels. Furthermore, modeling shows that independent glucose-induced oscillations of intracellular calcium can lead to slow oscillations in nucleotide concentrations, further predicting an influence of calcium flux on other metabolic oscillations. The results demonstrate the utility of comprehensive mathematical modeling in understanding the ramifications of potential defects in beta-cell function in diabetes.

Adenosine Diphosphate↗