Biomedical subjects

Rong Xia

Publications and source records attributed to Rong Xia.

14 recordsLinked to original sources

PubMed2006

Intracellular coiled-coil domain engaged in subunit interaction and assembly of melastatin-related transient receptor potential channel 2.

TRPM2 channels, activated by adenosine diphosphoribose and related molecules, are assembled as oligomers and most likely tetramers. However, the molecular determinants driving the subunit interaction and assembly of the TRPM2 channels are not well defined. Here we examined, using site-directed mutagenesis in conjunction with co-immunoprecipitation and patch clamp recording, the role of a coiled-coil domain in the intracellular C terminus of TRPM2 subunit in subunit interaction and channel assembly. Deletion of the coiled-coil domain resulted in severe disruption of the subunit interaction and substantial loss of the adenosine diphosphoribose-evoked channel currents. Individual or combined mutations to glutamine of the hydrophobic residues at positions a and d of the abcdef heptad repeat, key residues for protein-protein interaction, significantly reduced the subunit interaction and channel currents; the mutational effects on the subunit interaction and channel currents were clearly correlated. Furthermore, deletion of the coiled-coil domain in a pore mutant subunit abolished its dominant negative phenotypic functional suppression. These results provide strong evidence that the coiled-coil domain is critically engaged in the TRPM2 subunit interaction and such interaction is required for assembly of functional TRPM2 channel. The coiled-coil domain, which is highly conserved within the TRPM subfamily, may serve as a general structural element governing the assembly of TRPM channels.

Base Sequence↗

PubMed2006

[Migration and distribution of allogeneic T lymphocytes in organs of graft-versus-host disease mouse model].

This study was aimed to investigate the migration and distribution processes of allogeneic donor T lymphocytes in the organs of recipient mice. GVHD model was established by transfusion of the splenocytes of eGFP transgeneic C57BL/6 mice together with born marrow cells harvested from C57BL/6 mice into BALB/c mice underwent 8.0 Gy total body irradiation. The migration and homing of eGFP(+) cells were tracked by stereo-fluorescent microscopy or inverted fluorescent microscopy and flow cytometry. The enzyme linked immunosorbent assay (ELISA) was performed on supernatants from the tissue homogenates to detect the amount of MIP-1alpha. The results indicated that GVHD clinical manifestation and pathological changes of organs appeared on day 8 post transplantation. eGFP-positive donor T cells in recipient organs were observed by inverted fluorescence microscope in frozen section, or by stereo-fluorescence microscopy in living organs, such as liver, spleen, skin, lungs, bowels, and tongue. The highest expression of MIP-1alpha was on day 7 post transplantation in the liver (491.3 +/- 32.1 pg/ml), and day 3 post transplantation in the spleen (881.5 +/- 45.2 pg/ml), respectively (P < 0.05). It is concluded that GVHD was induced by splenocytes of eGFP transgeneic C57BL/6 mice. eGFP(+) cells in the organs can be observed by fluorescent microscopy. In this GVHD model, donor T cells proliferate and infiltrate in liver, skin, bowels, as well as lungs and tongue. MIP-1alpha may be in relation with the infiltration of T lymphocytes in liver and spleen.

Animals↗

PubMed2005

[Association of interleukin-6 induction and the novel gene LX3].

OBJECTIVE: To analyze the association between the expression of the novel gene LX3 and interleukin-6 (IL-6) induction, and explore a new target gene for action mechanism of IL-6. METHODS: The total RNA was extracted from U937 cells induced by IL-6 at different concentrations and varied lengths of time. Reverse transcriptional (RT)-PCR and Northern blotting were employed to determine the expression of LX3 and IL-6 induction. RESULTS: The expression of novel gene LX3 was increased while concentration of IL-6 was improved gradually. High expression was induced by IL-6, which was highest at the concentration was 500 ng/ml and no expression at 0 ng/ml. Time- expression pattern proved that expression of novel gene LX3 of higest at 8 hour after induced by IL-6. Northern blotting confirmed that the expression quantity of LX3 increased in U937 cells induced by IL-6. CONCLUSION: The quantity of LX3 expression is associated with the dose and duration of IL-6 induction, suggesting that LX3 gene is a novel gene correlated with IL-6 induction.

Gene Expression↗

PubMed2005

[Dynamic monitoring of graft-versus-host disease after allogeneic peripheral blood stem cell transplantation by soluble HLA-I antigen detection].

OBJECTIVE: To assess the value of dynamic monitoring of soluble human lymphocytic antigen-I (sHLA-I) in the prediction of graft-versus-host disease (GVHD) after allogeneic peripheral blood stem cell transplantation (PBSCT). METHOD: Sandwich enzyme-linked immunosorbent assay (ELISA) was used to quantitatively detect serum sHLA-I. The serum samples for testing were added into W6 32 monoclonal antibody-coated microtiter plate and incubated with anti-beta2m HRP followed by color development with the addition of the substrate. Serum sHLA-I level was measured in 63 healthy blood donors of Shanghai and in 24 PBSCT recipients before and and at different time points after the operation. RESULT: No changes in sHLA-I levels occurred in allogeneic PBSCT recipients without GVHD or with only grade I GVHD, but sHLA-I reached high levels in patients suffering GVHD II-IV(P<0.05), which was effectively lowered by the application of immunosuppressants. CONCLUSION: Measurements of sHLA-I levels can be valuable for monitoring GVHD after PBSCT.

Adolescent↗

PubMed2005

Establishment of a transplantable human myeloid BALB/c nude mouse model.

To establish a mouse model bearing transplantable human chronic myeloid leukemia for hematopoietic stem cell transplantation to treat leukemia, 4 - 5-week-old female BALB/c nude mice were given cyclophosphamide 2 mg/mouse at day -2, -1, and then the human chronic myeloid leukemia K562 cells were engrafted into the mice at day 0 by injection via tail vein or peritoneal cavity. PB and BM cells were collected, the CD45, CD13, and CD33 antigens were delected by using FCM, the bcr/abl fusion gene mRNA was examined by RT-PCR. The results showed that transplantable leukemic mice could be yielded from 4 - 5-week-old nude mice either by injection through tail vein or peritoneal cavity when the total number of inoculated tumor cells was more than 2 x 10(5) per mouse, whether being pretreated with 2 mg CTX/mouse or not. The transplanted mice could survive 30 - 60 day with leukemia. In conclusion, the mouse model bearing leukemia can be established by inoculation 2 x 10(5) K562 cells into immunodeficient BALB/c nude mice.

Animals↗

PubMed2005

[Comparison of Rhesus boxes in Hans and Uighurs].

OBJECTIVE: To study the difference and similarity between Hans and Uighurs in regard to Rhesus box and its significance. METHODS: The sequence specific primers of upstream, downstream and hybrid Rhesus boxes were designed on the basis of RHD gene sequence. The upstream, downstream and hybrid Rhesus boxes were determined by polymerase chain reaction-sequence specific primer(PCP-SSP) and mismatched PCR. RESULTS: The percentage of RHD-/RHD-, RHD+/RHD- and RHD+/RHD+ genotypes ascertained in the unrelated Hans with RhD(-) were 61.40%, 34.21% and 4.39% respectively, while those in the unrelated Chinese Uighurs with RhD(-) were 94.44%, 2.78% and 2.78% respectively. Furthermore, all 6 cases of some other minorities were RHD-/RHD- types. The percentage of RHD-/RHD- and RHD+/RHD- genotypes ascertained in the unrelated Chinese Uighurs were significantly higher than those in Chinese Hans (P < 0.01), whereas no statistically significant difference in the percentage of RHD+/RDH+ genotype between the two groups was observed (P > 0.05). CONCLUSION: The Rh blood group of Uighurs in Xingjiang possesses both Oriental and Caucasian characteristics, which embodies a special ethnical aspect of the Chinese nation and is in accord with the anthropologic research results.

China↗

PubMed2005

A putative generalized model of the effects and mechanism of action of high frequency electrical stimulation of the central nervous system.

High-frequency stimulation (HFS) of neural structures has been used since 1997 as an alternative to lesions in functional neurosurgery of movement disorders, and more recently, it has been applied to the treatment of epilepsies, obsessive-compulsive disorders, cluster headaches, and has other applications in experimental models, particularly for obesity. Although their clinical efficacy is not questioned, and that the effects most of the time parallel those of ablative techniques, leading to the concept of functional inhibition, the intimate mechanisms by which HFS induces excitation within fiber bundles and seems to inhibit cellular nuclei is still strongly debated. Principally due to the observation of long-term clinical effects over a period up to 15 years, it is clear that the mechanism is not due to a progressive lesion, as at every moment the interruption of stimulation reverses totally the effects. There is no current proof that long-term HFS is able to reset neural networks, or to induce profound modifications of the functional organization or of the synaptic connectivity. To understand what is responsible for the immediate, reversible and adaptable effects of HFS, several mechanisms must be considered, which might be involved simultaneously or in sequence: i) Jamming of neural transmission through stimulated nuclei is one possibility, based on the principle that the regular imposed activity might drive the neurons to fire in a regular pattern, making it impossible to transmit more subtle messages, either normal or abnormal. Although it is difficult to prove this type of mechanism, it might account for the reports of increased activity following HFS in various structures. ii) Direct inhibition of spike initiation at the level of the membrane could be due to activation of inhibitory terminals, particularly gaba-ergic, or by a blockade of the voltage gated ion channels. iii) Recent data show that HFS decreases the production and release of low molecular weight proteic neurotransmitters, which could account for the functional inhibition while the efferent axon is still excited by the electrical stimulus. iv) Retrograde activation of upstream neuronal structures, as reported in the external pallidum during stimulation of STN, might be responsible of additional jamming-like effects due to collisions with descending spikes.

Animals↗

PubMed2005

Ex vivo expansion of T, NK and CD34+ cells from umbilical cord blood.

Umbilical cord blood stem cell transplantation (CBSCT) has made significant progress in treatment of lethal congenital or malignant disorders. Both the incidence and severity of GVHD from CBSCT were lower than that from bone marrow and peripheral blood stem cell transplantation, particularly for adult patients, but these advantages were also associated with higher rates of relapse. The immune-mediated effect of natural killer and cytotoxic T cells against residual tumor cells were shown to prevent relapse and to induce remission after bone marrow transplantation. To explore possibility of ex vivo expansion of T, NK and CD34(+) cells from umbilical cord blood, cord blood was expanded ex vivo with different combinations of cytokines, T and NK cells proliferation and differentiation were observed. CB MNCs were separated in Ficoll-Isopaque column and cultured in IMDM for 14 days with different recombinant cytokines. Cultured cells were collected and analyzed for progenitor/stem cell immunophenotyping at day 0, 3, 7, and 14 by using flow cytometry. The results indicated that all test groups cultured with different combinations of SCF, IL-3, IL-6, IL-7, IL-2 showed significant expansion of UCB MNC, compared with the group without cytokines. All test groups showed expansion effects on CD34(+) cells, CD34(+) percentage went up from 1.6% in fresh CB to the highest 11.9% in group D (SCF + IL-3, IL-6, IL-2). The CD34(+) cells peak displayed at day 7 of culture in group A and D, while in other two groups B and C appeared at day 14 of culture. The expansion multiple of CD34(+) cells in all test groups at day 7 of culture were from 10 to 50. The average value of CD3(+) T cell in fresh UCB was 18.7 +/- 4.3%, the CD3(+) T cells decreased sharply in the medium without any interleukin, while obvious increase were observed in the other test groups containing different combinations of cytokines. The maximal expansion multiple of CD3(+) T cells reached 2 times of the fresh UCB level. CD56(+) cells amounted to 3.6 +/- 1.9% of fresh UCB, CD56(+) cell number increased significantly only in medium containing IL-2. It is concluded that T cells, NK cells as well as stem/progenitor cells can be expanded in the same time from CB-MNC with the combinations of cytokines.

Antigens, CD34↗

PubMed2005

[A method for Rhesus box test].

To study the method for Rhesus box test and its significance, the sequence specific primers of upstream, downstream and hybrid Rhesus boxes were designed according to RhD gene sequence; the upstream, downstream and hybrid Rhesus boxes were determined by PCP-SSP and mismatched PCR. The results showed that this method was confirmed by DNA Standard test. It was shown that in unrelative RhD positive individuals RHD(+)/RHD(-), RHD(+)/RHD(+) genotype accounted for 9.00%, 91.00% respectively, and in RhD negative individuals RHD(+)/RHD(-), RHD(+)/RHD(+), RHD(-)/RHD(-) genotype were 26.14%, 3.92%, 69.94% respectively. It is concluded that the method of Rhesus box test was confirmed to be reliable and can be used for the identification of RhD haplotype gene structure, as well as for study on inheritance, clinical transfusion and neonatal hemolytic diseases.

Base Sequence↗

PubMed2003

[Biological analysis of a novel gene related with interleukin-6].

OBJECTIVE: To understand the action mechanism of interleukin (IL)-6 through investigation of its related genes. METHODS: Using electronic cloning with IL-6-related expressed sequence tags (ESTs), a novel gene at its full length of 924 bp was acquired. Reverse transcriptase-PCR method was subsequently employed to amplify the cDNA of this gene from the total RNA of human U937 cells, which were previously activated with 100 ng/ml IL-6 for 8 h. The fragment was then ligated into the pGEM-Teasy vector and sequence analysis was conducted. RESULT: The whole cDNA gene was successfully fished. CONCLUSION: Electronic cloning technology can be instrumental in identifying novel genes.

Amino Acid Sequence↗

PubMed2003

[ABO blood group typing for infants and its application for clinical transfusion].

To study the correct method for determining ABO blood types in infants and its influencing factors, blood types of 33 infants under 6 months old were determined by routine serological method, micro-column gel typing system and PCR-SSP genotyping method. Of the 33 cases with discrepant results of ABO blood type by different methods, the blood types of 32 cases were discrepant between red cell and serological typings in the routine serological method, and a false coincidence in 1 case was caused by bacterial infection resulting in B-like antigen. Correct blood typing was obtained in 27 cases with a correct rate of 84.4% (27/32) by using micro-column gel typing system. PCR-SSP method gave correct results in all of 33 cases. There was a significant difference between the results of micro-column gel typing system and PCR-SSP. It is concluded that to determine ABO blood type for infants < 6 months old, it is recommended to adopt micro-column gel typing system method, and what must be taken into account is the possible false coincidence caused by bacterial infection resulting in B-like antigen. In micro-column gel typing system, if the results of red cell and serological typing are identical, the principle is that blood transfusion must be performed with same ABO blood type between recipient and donor. If not, washed O red blood cells should be used for infants, and then change to transfusion with identical blood group according to PCR-SSP typing results.

ABO Blood-Group System↗

PubMed2003

[Camouflage of HLA-I antigen in lymphocyte surface].

The objective of this study was to investigate the method and effect of blocking the specific reaction between lymphocyte HLA-I antigen and its antibody. The lymphocytes were disposed with 12 mmol/L methoxypolyethelene glycol benzotriazol carbonate (mPEG-BTC) in concentration gradient in PBS (pH 7.4) at 22 degrees C. The effect of the modified lymphocytes was detected by microlymphocytotoxicity assay. The results showed that lymphocytes modified by mPEG-BTC did not react with related HLA-I antibodies in microcytotoxicity test. It is suggested that the specific reaction between HLA-I antigen of lymphocyte and HLA-I antibodies can be completely camouflaged by mPEG-BTC in PBS (pH 7.4) under 22 degrees C room temperature.

Antigen-Antibody Reactions↗

PubMed2002

[Identification of estazolam, alprazolam and triazolam in human urine by LC/MSn].

AIM: To investigate the fragmentation behavior of triazolobenzodiazepines and to develop a specific, sensitive and rapid LC/MSn assay for simultaneous determination of estazolam, alprazolam and triazolam in human urine. METHODS: After oral administration of a single 4 mg dose of the drugs to each of three healthy volunteers, urine samples were purified by solid-phase extraction, and then injected into an ODS column (150 mm x 4.6 mm) with a mobile phase of methanol-water (8:2) for LC/MSn analysis. The structures of estazolam, alprazolam and triazolam in human urine were identified by direct comparison of the observed mass spectra and the chromatographic retention time with those of the reference substance. The mass spectrometer (Finnigan LCQ) was operated in positive mode and in two scan modes including SIM and full scan MS/MS mode. The obtained mass spectra was analyzed assisted with the software Mass Frontier 1.0 for their fragmentation pathways. RESULTS: The full scan MS/MS spectra of each compound gave characteristic fragment ions of [M + H - N2]+ and [M + H - Cl]+. The detection limit was below 0.5 ng.mL-1 for estazolam, alprazolam and triazolam in human urine. CONCLUSION: The method is useful in forensic and clinical toxicology in which unequivocal identification of eatazolam, alprazolam and triazolam is desired.

Alprazolam↗

PubMed2001

[Research of Typing for HLA-A, -B on Cord Blood Lymphocytes]

Serological typing for HLA-A, -B has been used for a long time. Recently with the developing of molecular biology technologies, HLA-A, -B typing is now turning to genotyping methods. In our study, the capacity of PCR-SSP in solving problems in HLA-A, -B typing with serological methes was evaluated. With this aim the serological method was compared with PCR-SSP in 102 cord blood samples, and the results showed that 18.6% of 102 cord blood samples can't give a satisfactory detection, for 14 samples, give discrepant results with the 2 methods. It is mainly due to weak expression of HLA class I cord blood lymphocytes and the cross reaction of some antigens. About B 15 group, the further study was made, it was found that most of the B 15 splits is wrongly disassigned, especially among the B62-B75, B75/*1511(+)-B75/*1511(-), B46-*1511 antigens. It was concluded that DNA typing is more preferable than serological typing, about B 15 group, the subtyping or high resolution typing can be fulfilled at first in China.

Journal Article↗