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Biomedical subjects

Y Xi

Publications and source records attributed to Y Xi.

At least 19 recordsLinked to original sources
PubMed2006

Muscle-specific creatine kinase gene polymorphism and running economy responses to an 18-week 5000-m training programme.

OBJECTIVE: To investigate the association between muscle-specific creatine kinase (CKMM) gene polymorphism and the effects of endurance training on running economy. METHODS: 102 biologically unrelated male volunteers from northern China performed a 5000-m running programme, with an intensity of 95-105% ventilatory threshold. The protocol was undertaken three times per week and lasted for 18 weeks. Running economy indexes were determined by making the participants run on a treadmill before and after the protocol, and the A/G polymorphism in the 3' untranslated region of CKMM was detected by polymerase chain reaction-restricted fragment length polymorphism (NcoI restriction enzyme). RESULTS: Three expected genotypes for CKMM-NcoI (AA, AG and GG) were observed in the participants. After training, all running economy indexes declined markedly. Change in steady-state consumption of oxygen, change in steady-state consumption of oxygen by mean body weight, change in steady-state consumption of oxygen by mean lean body weight and change in ventilatory volume in AG groups were larger than those in AA and GG groups. CONCLUSIONS: The findings indicate that the CKMM gene polymorphism may contribute to individual running economy responses to endurance training.

Adolescent↗
PubMed2006

Polymorphisms in the HBB gene relate to individual cardiorespiratory adaptation in response to endurance training.

OBJECTIVE: The crucial role of haemoglobin in endurance performance has been well documented. We examined whether polymorphisms in the HBB gene modified aerobic capacity. METHODS: 102 recruits were trained by running 5000 m three times per week for 18 weeks. Exercise intensity progressively increased from an initial heart rate corresponding to 95% of the individual baseline ventilatory threshold during the first 10 weeks to 105% during the last 8 weeks. The phenotypes measured were running economy and VO(2)max. Running economy was determined by measuring submaximal VO(2) for 5 min at a constant running speed of 12 km.h(-1) and VO(2)max was obtained during an incremental test to exhaustion. Genomic DNA was extracted from white cells of peripheral blood and the -551C/T, intron2,+16C/G and +340 A/T genotypes were examined relative to the TAA site variants by PCR-RFLP. RESULTS: Genotype distributions were in Hardy-Weinberg equilibrium at three loci. None of the running economy and VO(2)max-related traits were associated with the three polymorphisms or haplotypes at baseline, while the training response of running economy was associated with -551C/T and intron2,+16C/G polymorphisms. Subjects homozygous for intron2,+16C/C or -551C/C had decreased oxygen cost of running compared to the other individuals. DISCUSSION: It was concluded that the -551C/C or intron2,+16C/C genotype might explain part of the individual variation in the cardiorespiratory adaptation to endurance training.

Adaptation, Physiological↗
PubMed2001

Control of osteoclastogenesis and bone resorption by members of the TNF family of receptors and ligands.

Skeletal mass is maintained by a balance between cells which resorb bone (osteoclasts) and cells which form bone (osteoblasts). Bone development and growth is an on-going, life-long process. Bone is formed during embryonic life, grows rapidly through childhood, and peaks around 20 years of age (formation exceeds resorption). For humans the skeleton then enters a long period, approximately 40 years, when bone mass remains relatively stable. Skeletal turnover continues but the net effect of resorption and formation on bone mass is zero. For women this ends when they enter menopause and similar bone loss occurs for men, but later in life. These opposite functions are coupled, resorption precedes formation, and osteoblasts, or their precursors, stromal cells, regulate osteoclast formation and activity. Until recently, the molecular nature of this regulation, was poorly understood. However, recent observations have identified members of the TNF family of ligands and receptors as critical regulators of osteoclastogenesis. Osteoprotegerin (OPG) a decoy receptor was first identified. Its ligand, receptor activator of nuclear factor-kappaB ligand (RANKL), was quickly found, and shown to be expressed on stromal cells and osteoblasts. Its cognate receptor, RANK, was found to be expressed in high levels on osteoclast precursors. The interaction between RANKL and RANK was shown to be required for osteoclast formation. These observations have provided a molecular understanding of the coupling between osteoclastic bone resorption and osteoblastic bone formation. Moreover, they provide a framework on which to base a clear understanding of normal (e.g. postmenopausal osteoporosis and age associated bone loss) and pathologic skeletal changes (e.g. osteopetrosis, glucocorticoid-induced osteoporosis, periodontal disease, bone metastases, Paget's disease, hyperparathyroidism, and rheumatoid arthritis).

Animals↗
PubMed2001

A novel human hydroxysteroid dehydrogenase like 1 gene (HSDL1) is highly expressed in reproductive tissues.

We report the cloning and characterization of a novel human hydroxysteroid dehydrogenase like gene (HSDL1) located on human chromosome 16q24.2. The HSDL1 cDNA is 3407 base pair in length, encoding a 309 amino acid polypeptide related to human 17beta-HSD3. Northern blot reveals that the HSDL1 is highly expressed in testis and ovary. In situ hybridization indicates that the expression of HSDL1 is predominantly increased in the prostate cancer tissue compared with the normal prostate tissue, which suggests that the gene expression is important to the arising of prostate cancer.

Amino Acid Sequence↗
PubMed2001

Inflammation and bony changes at the temporomandibular joint.

Cytokines help mediate the acute and chronic inflammation and associated destruction of connective tissue in arthritic temporomandibular joints (TMJ). The proinflammatory cytokines TNFalpha, IL-1beta, IL-6, IL-8, and IFN-gamma are associated with inflammation in synovial joints and connective tissue destruction. Therefore, the increased levels of these cytokines in the synovial fluid of temporomandibular disorder (TMD) patients would be expected. Conversely, IL-1ra and IL-10 acts as inhibitors to these proinflammatory cytokines. Thus, in TMD patients, low levels of IL-1ra and IL-10 might be expected. A review of studies from multiple investigators confirms that proinflammatory cytokine levels increase in TMD patients, IL-1ra levels are also increased, and IL-10 levels remain unchanged. Because IL-10 can inhibit TNFalpha, IL-1, IL-6, and IL-8, the lack of IL-10 in the TMJ in the face of the other studies showing increases in TNFalpha, IL-1beta, IL-6, and IL-8 could partially explain the exacerbation of the associated osteoarthritis. In addition, although IL-1ra levels are elevated in most of the TMD patients, the increases do not appear to be sufficient to inhibit the inflammation and connective tissue degradation associated with IL-1beta. Thus, it appears that treatment of TMD requires a delicate balance between proinflammatory cytokines and cytokine inhibitors such as IL-1ra and IL-10.

Case-Control Studies↗
PubMed2001

[Retrospective analysis of endometrial neoplasms treated by different therapeutic modalities].

OBJECTIVE: To compare the therapeutic effects of different remedies in patients with endometrial carcinoma. METHODS: Total of 386 patients with metracarcinoma underwent 3 different treatments: (1) operation only 145 cases; (2) operation and complemental radiotherapy 161 cases; (3) radiotherapy only 80 cases. Then they were followed up for 5 years and more. RESULTS: The 5-year survival rates of operation group were 78.9% (56/71), 61.0% (25/41) and 18.2% (6/33) in stage I, stage II, and stage III-IV respectively, for operation and complemental radiotherapy, they were 75.0% (33/44), 59.5% (44/74) and 48.8% (21/43), for radiotherapy, 34.8% (8/23), 18.8% (3/16) and 0.0% (0/41). There was no difference between operation group and operation plus radiotherapy in patients with stage I and stage II (P > 0.05). However the 5-year survival rates were significantly higher in operation plus complemental radiotherapy group and those only received operation in stage III stage IV patients (P < 0.001). And no matter in what stages, the therapeutic effect was worse in radiotherapy group than other two groups (P < 0.001). CONCLUSION: The remedies with operation as main measure are the best choice for metacarcinoma, radiotherapy merely is fit with those who can not be operated on.

Adult↗
PubMed2000

Human immunodeficiency virus reverse transcriptase and protease sequence database.

The HIV RT and Protease Sequence Database is an online relational database that catalogs evolutionary and drug-related human immunodeficiency virus (HIV) reverse transcriptase (RT) and protease sequence variation (http://hivdb.stanford.edu). The database contains a compilation of nearly all published HIV RT and protease sequences including International Collaboration database submissions (e.g., GenBank) and sequences published in journal articles. Sequences are linked to data about the source of the sequence sample and the antiretroviral drug treatment history of the individual from whom the isolate was obtained. The database is curated and sequences are annotated with data from >230 literature references. Users can retrieve additional data and view alignments of sequence sets meeting specific criteria (e.g., treatment history, subtype, presence of a particular mutation). A gene-specific sequence analysis program, new user-defined queries and nearly 2000 additional sequences were added in 1999.

Databases, Factual↗
PubMed2000

[Effect of initial population density on resting egg formation of rotifer Brachionus calyciflorus].

With the method of population accumulative culture, the effect of initial population density on the formation of resting eggs of freshwater rotifer(Brachionus calyciflorus), and on the rates of mictic female and fertilization was studied. During 11 days culture, the productivity and the formation efficiency of resting eggs, and the mean rate of mictic female were the biggest when the initial population density was 1.0-10.0 ind.ml-1, second by the density of 20.0 ind.ml-1, and the lowest by the density of 50.0 ind.ml-1. There was no significant effect of initial population density on the fertilization rate. Statistical analysis on maximum formation efficiency of resting eggs, their emergence and productivity showed that when the production of resting eggs was large-scaled proceeded, the feasible initial population density should be 10.0 ind.ml-1, and the corresponding time should be 6 days to obtain a higher yield of resting eggs and a higher formation efficiency.

Animals↗
PubMed2000

[The expression of interleukin-6 mRNA and autosecretion in human leukemic cells].

OBJECTIVE: To make a comprehensive and systematic study on the constructive expression of IL-6 mRNA and IL-6 autosecretion in human leukemic cells and discuss the effect of IL-6 autosecretion on the specific binding of IL-6-PE40 fusion protein to targeted leukemic cells. METHODS: Semi-quantitative RT-PCR, sequencing and ELISA were used to detect the constructive expression of IL-6 mRNA and autosecretion level of IL-6 protein in human leukemic cell lines, such as U937, HL60, KG1, TF1, K562, HuT28, CEM and Raji. RESULTS: The relative expression level of IL-6 mRNA in myelocytic, monocytic and erythrocytic leukemic cell lines including HL60, U937, KG1 and TF1 and lymphoblastic leukemic cell lines such as CEM, HuT28 and Raji is very weak, ranging from 0.03 to 0.07. However, K562, an chronic myelocytic leukemic cell line, had the highest level 1.25 among the 8 leukemic cell lines and the level was also higher than that of the positive control U266 multiple myeloma cell line. Based on ELISA assay of IL-6, there were remarkable differences between the 8 leukemic cell lines, their secretion of IL-6 could be divided into 3 levels, i.e. high, moderate and low secretion type. CONCLUSION: These observations imply that the intrinsic expression and secretion of IL-6 differ obviously among different leukemic cell lines. Autocrine IL-6 may prevent IL-6-PE40 fusion protein from specific binding to targeted leukemic cells and consequently affect its specific killing toxicity.

Cell Line, Tumor↗
PubMed2000

[Combined five tumor markers in detecting primary hepatic carcinoma].

OBJECTIVE: To increase the detection rate of primary hepatic carcinoma (PHC) and to diagnose PHC earlier. METHODS: AFP was combined with r-glutamyle transpeptidase (r-GT), alpha-fucosidase (AFU), tumor necrosis factor-alpha (TNF-alpha) and DR-70. RESULTS: The positive detection rate of PHC negative AFP with combined four markers was 9.4%. The total positive detection rate of PHC with combined five tumor markers reached 98.0% which was significantly higher than that with AFP (P < 0.01). CONCLUSIONS: The positive detection rate of PHC can be increased by combined five tumor markers. It is helpful in diagnosing PHC earlier and can differentiate PHC from liver cirrhosis.

Biomarkers, Tumor↗
PubMed2000

[Effects of different cryoprotectants on biological properties of hematopoietic cells derived from cord blood].

OBJECTIVE: To search for effective cryoprotectants that can be used in cord blood bank to cryopreserve hematopoietic cells. METHODS: Four kinds of combined reagents were used to cryopreserve cord blood cells. The effects of these cryoprotectants on biological properties of hematopoietic cells were monitored and compared after the cells were refrigerated for 1 to 4 months. The detected biological properties included the number of total nucleated cells (TNC), CD(34)(+) cells and CFCs. RESULTS: The cryoprotectants of Dextran-40 + 10%DMSO resulted in the highest recovery rates, TNC, CD(34)(+) cells and CFCs were 77.8%, 78.5% and 87.2%, respectively. The combination of 10%DMSO + 6% AB serum + 5%HES led to the lowest recovery rates. CONCLUSION: Dextran-40 + 10%DMSO is an ideal cryoprotectant combination for cryopreserving hematopoietic cells in the cord blood bank.

Antigens, CD34↗
PubMed1998

[Experimental study on the role of the pedicle of the subdermal vascular network skin flap].

OBJECTIVE: The experiment was to investigate the role of the pedicle of the subdermal vascular network skin flap. METHODS: Ten healthy white pigs, weighting from 20 to 25 kg were used. The subdermal vascular network skin flap and the traditional skin flap were designed and created on each side of the animal's flank. The traditional skin flap on the contralateral side of the flank was used as control. Flap survival was studied by gross observation and ECT examination of isotope distribution. RESULTS: There were significant differences between the two groups in mean survival length and area (P < 0.05). In both groups the radioactive isotope gathering is restricted proximally with a ratio of length to width of (1-1.5):1. CONCLUSION: The presence of the pedicle of the subdermal vascular network skin flap makes no difference compared the traditional skin flap.

Animals↗
PubMed1997

[Morphological and cytochemitry features of CD34+ hematopoietic cells isolated from human bone marrow].

OBJECTIVE: To explore the cytomorphological and cytochemitry features of CD34+ hematopoietic cells. METHODS: Highly purified CD34+ hematopoietic cells isolated from human bone marrow by a two-step method of immunomagnetic beads-FACS sorting were comprehensively examined. RESULTS AND CONCLUSION: CD34+ hematopoietic cells could be sorted into three types in light of morphology and cytochemical staining. Type I was considered as candidates for stem cells,which were most blastlike in morphology and slightly larger than lymphocytes in size with negative reactions to all cytochemical stainings. Type II was considered as multipotent progenitor cells, with sizes similar to small lymphocytes and negative reactions to all cytochemical stainings. Type III was identified as committed progenitor cells whose sizes were heterogeneous and whose reactions to cytochemical stainings ranged from +/- to + +.

Antigens, CD34↗
PubMed1997

[Expression of apoptosis regulating proteins P 53, c-myc and bcl-2 on CD34+ hematopoietic cells isolated from human bone marrow].

OBJECTIVE: To show the coexpression levels of P 53, c-myc or bcl-2, three key apoptosis-regulating proteins on CD34+HC and bone marrow mononuclear cells (BMMNC). METHODS: IsolexTM50 or CIMS-100 systems of immunomagnetic bead separation and two-dimensional flow cytometric analysis of the immunofluorescence double staining were used. RESULTS: With 90%-95% purity of CD34+HC measured by FACS, we found that expression levels of P53, c-myc, and bcl-2 on both CD34+HC and BMMNC were as follows: CD34+/P53 + 0.1-00.8% versus BMMNC 0.1-0.6%; CD34+/c-myc+2.4%-11. 3% versus BMMNC 0.1-0.4%; CD34+/bcl-2+0.5-1.6% versus BMMNC 0.1-0.8%. Coexpression of c-myc and bcl-2 on CD34+HC was significantly higher than those observed on BMMNC respectively. CONCLUSION: It could be speculated that apoptosis-regulating proteins P53, c-myc and bcl-2 play a key role in the control of the survival, proliferation, differentiation, maturation and death in hematopoietic cells of physiological state, suggesting that these proteins balance the production numbers and quality of hematopoietic cells.

Antigens, CD34↗