Biomedical subjects

Y Xue

Publications and source records attributed to Y Xue.

At least 55 records · Page 3Linked to original sources

PubMed2001

Natrialba hulunbeirensis sp. nov. and Natrialba chahannaoensis sp. nov., novel haloalkaliphilic archaea from soda lakes in Inner Mongolia Autonomous Region, China.

Two haloalkaliphilic archaeal strains, X21T and C112T, were isolated from soda lakes in Inner Mongolia Autonomous Region, China. Their morphology, physiology, biochemical features, polar lipid composition and 16S rRNA genes were characterized in order to elucidate their taxonomy. According to these data, strains X21T and C112T belong to the genus Natrialba, although there are clear differences with respect to their physiology and polar lipid composition between the two strains and the type species, Natrialba asiatica. On the basis of low DNA-DNA hybridizations, these two strains should be considered as new species of genus Natrialba. The names Natrialba hulunbeirensis sp. nov. (type strain X21T = AS 1.1986T = JCM 10989T) and Natrialba chahannaoensis sp. nov. (type strain C112T = AS 1.1977T = JCM 10990T) are proposed.

Base Composition↗

PubMed2001

Characterization and analysis of the PikD regulatory factor in the pikromycin biosynthetic pathway of Streptomyces venezuelae.

The Streptomyces venezuelae pikD gene from the pikromycin biosynthetic cluster was analyzed, and its deduced product (PikD) was found to have amino acid sequence homology with a small family of bacterial regulatory proteins. Database comparisons revealed two hypothetical domains, including an N-terminal triphosphate-binding domain and a C-terminal helix-turn-helix DNA-binding motif. Analysis of PikD was initiated by deletion of the corresponding gene (pikD) from the chromosome of S. venezuelae, resulting in complete loss of antibiotic production. Complementation by a plasmid carrying pikD restored macrolide biosynthesis, demonstrating that PikD is a positive regulator. Mutations were made in the predicted nucleotide triphosphate-binding domain, confirming the active-site amino acid residues of the Walker A and B motifs. Feeding of macrolide intermediates was carried out to gauge the points of operon control by PikD. Although the pikD mutant strain was unable to convert macrolactones (10-deoxymethynolide and narbonolide) to glycosylated products, macrolide intermediates (YC-17 and narbomycin) were hydroxylated with high efficiency. To study further the control of biosynthesis, presumed promoter regions from pik cluster loci were linked to the xylE reporter and placed in S. venezuelae wild-type and pikD mutant strains. This analysis demonstrated that PikD-mediated transcriptional regulation occurs at promoters controlling expression of pikRII, pikAI, and desI but not those controlling pikRI or pikC.

Amino Acid Sequence↗

PubMed2001

EBNA-LP associates with cellular proteins including DNA-PK and HA95.

EBNA-LP-associated proteins were identified by sequencing proteins that immunoprecipitated with Flag epitope-tagged EBNA-LP (FLP) from lymphoblasts in which FLP was stably expressed. The association of EBNA-LP with Hsp70 (72/73) was confirmed, and sequences of DNA-PK catalytic subunit (DNA-PKcs), HA95, Hsp27, prolyl 4-hydroxylase alpha-1 subunit, alpha-tubulin, and beta-tubulin were identified. The fraction of total cellular HA95 that associated with FLP was very high, while progressively lower fractions of the total DNA-PKcs, Hsp70, Hsp 27, alpha-tubulin, and beta-tubulin specifically associated with EBNA-LP as determined by immunoblotting with antibodies to these proteins. EBNA-LP bound to two domains in the DNA-PKcs C terminus and DNA-PKcs associated with the EBNA-LP repeat domain. DNA-PKcs that was bound to EBNA-LP phosphorylated p53 or EBNA-LP in vitro, and the phosphorylation of EBNA-LP was inhibited by Wortmannin, a specific in vitro inhibitor of DNA-PKcs.

DNA-Activated Protein Kinase↗

PubMed2001

Branching activity in the human prostate: a closer look at the structure of small glandular buds.

OBJECTIVE: Knowledge regarding cell biologic characteristics of small solid glandular buds in the prostate and their relationship with branching activity in the human prostate is still fragmentary. Our object was to demonstrate, on the basis of immunophenotype, loci that harbor the potential for branching activity within the adult human prostate. MATERIALS AND METHODS: Semiserial sectioning was performed on 13 adult prostates in an effort to identify structures in the prostate that could be considered foci of growth. Selected slides were stained with biomarkers for basal/luminal cells (keratins), proliferation (MIB-1), apoptosis inhibitor (bcl-2), intercellular adhesion (E-cadherin), and stromal-epithelial interactions (tenascin-C). Results were compared with fetal and prepubertal human prostates and microdissected rat prostates. RESULTS: Five histologic epithelial structures were identified in 19 paraffin blocks, which on serial sectioning showed morphologic transitions with a common pattern, consisting of reduction in number and caliber of acini until small solid buds of epithelial cells were reached. Immunophenotypically, the small solid glandular buds had a basal-cell keratin phenotype, expression of bcl-2 in virtually all cells, high proliferative activity, prominent intracellular localization of E-cadherin, and enhanced periglandular tenascin-C immunoreactivity. The budding tips in fetal and prepubertal prostates revealed an immunostaining pattern identical to the small solid glandular buds in the adult, but different to the rat prostate. CONCLUSIONS: Our data suggest that dispersed small solid glandular buds have a capacity for growth, and as such may be considered foci of resumed reawakening branching activity with in the adult human prostate.

Adult↗

PubMed2001

Mesodermal patterning defect in mice lacking the Ste20 NCK interacting kinase (NIK).

We have previously shown that the Drosophila Ste20 kinase encoded by misshapen (msn) is an essential gene in Drosophila development. msn function is required to activate the Drosophila c-Jun N-terminal kinase (JNK), basket (Bsk), to promote dorsal closure of the Drosophila embryo. Later in development, msn expression is required in photoreceptors in order for their axons to project normally. A mammalian homolog of msn, the NCK-interacting kinase (NIK) (recently renamed to mitogen-activated protein kinase kinase kinase kinase 4; Map4k4), has been shown to activate JNK and to bind the SH3 domains of the SH2/SH3 adapter NCK. To determine whether NIK also plays an essential role in mammalian development, we created mice deficient in NIK by homologous recombination at the Nik gene. Nik(-/-) mice die postgastrulation between embryonic day (E) 9.5 and E10.5. The most striking phenotype in Nik(-/-) embryos is the failure of mesodermal and endodermal cells that arise from the anterior end of the primitive streak (PS) to migrate to their correct location. As a result Nik(-/- )embryos fail to develop somites or a hindgut and are truncated posteriorly. Interestingly, chimeric analysis demonstrated that NIK has a cell nonautonomous function in stimulating migration of presomitic mesodermal cells away from the PS and a second cell autonomous function in stimulating the differentiation of presomitic mesoderm into dermomyotome. These findings indicate that despite the large number of Ste20 kinases in mammalian cells, members of this family play essential nonredundant function in regulating specific signaling pathways. In addition, these studies provide evidence that the signaling pathways regulated by these kinases are diverse and not limited to the activation of JNK because mesodermal and somite development are not perturbed in JNK1-, and JNK2-deficient mice.

Animals↗

PubMed2001

t(8;21;8)(p23;q22;q22): a new variant form of t(8;21) translocation in acute myeloblastic leukemia with maturation.

The complex variants of t(8;21) involving chromosomes 8 and 21 as well as a variable chromosome account for 1.1-5% of acute myeloid leukemia (AML) patients. This paper reports a case of AML-M2 with t(8;21;8) translocation for the first time. The patient was a female, aged 47 years. Her myelogram was compatible with AML-M2. Chromosome study using R-banding technique revealed a karyotype 46, XX, t(8;8)(p23;q22). Dual-color FISH assay with two probes P1 164(green signal) and YAC 225B8 (red signal) both of which closely located on the 8q showed that one yellow signal consisting of a green signal and a red signal and one red signal appeared on the long and the short arm of the same der(8) chromosome, respectively, further confirming this translocation occurred between both homologous chromosomes 8. RT-PCR analysis detected the AML1/ETO fusion transcript in our patient, thus indicating that this chromosomal aberration was, in fact, a complex three-way rearrangement t(8;21;8)(p23;q22;q22). In conclusion, combining conventional karyotype, FISH or RT-PCR analyses is a rational strategy for identification of the complex variants of t(8;21) translocation.

Bone Marrow Cells↗

PubMed2001

[Effects of conjugated linoleic acid on the metastasis of mouse melanoma B16-MB].

In order to explore the effects of conjugated linoleic acid on tumor metastasis, the proliferation, gap junction intercellular communication (GJIC), adhesion to extracellular matrix, and metastasis cascades of tumor cells were imitated in cell culture. The results showed that 100 and 200 mumol/L conjugated linoleic acid could inhibit the proliferation and the adhesion of tumor cells to extracellular matrix, and could recover its gap junction intercellulor communication.

Animals↗

PubMed2001

[Investigation on the mechanics of adhesion to the selective extracellular matrix coated surfaces of lung cancer cells].

The adhesion properties of tumor cells with extracellular matrix(ECM) are closely associated with their invasion and metastasis. Our work reported here was intended reveal the relevant biomechanical and biorheological manifestations of human lung cancer. Using micropipette aspiration technique, we investigated quantitatively the adhesive mechanics properties of high metastatic human giant cell carcinoma(PG) cells as well as low metastatic adenocarcinoma(PAa) cells of lung based on cell culture in vitro. The results showed that the adhesion forces of PAa and PG cells to collagen IV were significantly higher than those to glass surfaces, but at the lower concentrations(1.00 microgram/ml and 2.00 micrograms/ml) of collagen IV, the amplitude for the increase of adhesion forces of PG cells were less than the amplitude for that of PAa cells, and most of the adhesion force values of PAa cells to the coated surfaces of incorporation of laminin along with 2 micrograms/ml collagen IV were significantly greater than those of PG cells. At the lower concentrations(0.625 microgram/ml for PAa cells, and 0.625 microgram/ml, 1.25 micrograms/ml for PG cells) of laminin tested, the adhesion force values of PAa and PG cells all decreased, but the amplitude and level for the decreased values of adhesion forces of PG cells were greater than those for the PAa cells. In conclusion, the adhesive and proteolytic behaviour of cancer cells to extracellular matrix might be mediated mainly by tumor cell membrane receptors such as integrin receptors and laminin receptors, it might affect the biological characteristics and the metastasis of the tumor cells. The results may benefit to explain some questions in biomechanical views about how the highly metastatic PG cells are prone to migration and invasion.

Adenocarcinoma↗

PubMed2001

[Cytogenetic analysis on 1058 cases of acute nonlymphocytic leukemia].

OBJECTIVE: To evaluate the karyotypic status in a large series of acute nonlymphocytic leukemia(ANLL) cases. METHODS: A total of 1058 cases of de novo ANLL were studied. Chromosome preparations were made on bone marrow cells using direct method and short-term culture. Karyotypes were analyzed by R-banding in all cases and G-banding in some cases in addition. RESULTS: Six hundred and thirty cases (60%) had clonal chromosomal abnormalities. 25 categories of major karyotypic abnormalities were found. Among them, 11 were the specific chromosomal rearrangements seen in 481 cases, accounting for 76% of the total number of patients with karyotypic abnormalities. Isolate trisomy 8 (21 cases) was the most common numerical abnormality. t(15;17)(211 cases) and t(8;21)(200 cases) were the most frequent structural abnormalities. The 1.1% of M(2), 72% of M(3), 71% of M(4E0), 50% of M(2), 6 % of M(5) and 1.4% of M(2) had t(7;11), t(15;17), inv(16), t(8;21), t/del(11q 23) and t/del(12p) abnormalities, however, the 100% of t(7;11), 100% of t(15;17 ), 100% of inv(16), 88.5% of t(8;21), 83% of t/del(11q23) and 62% of t/del(12p) were detected in patients with M(2), M(3), M(4E0), M(2), M(5) and M(2) subtypes, respectively. CONCLUSION: By conventional banding technique, including R- and G-bandings, 60% of patients with ANLL may be found to have clonal chromosomal abnormalities which are predominantly specific chromosomal rearrangements correlated with specific FAB subtypes. Thus, karyotype is an important indicator for diagnosis and classification of ANLL.

Adolescent↗

PubMed2001

[Detection of monosomy 7 or 7q- in cases of myelodysplastic syndrome].

OBJECTIVE: To investigate the value of interphase fluorescence in situ hybridization(FISH) in the detection of monosomy 7 (-7)or deletion of long arm of chromosome 7(7q-) in the cases of myelodysplastic syndrome (MDS). METHODS: Forty-six cases of MDS and 10 normal controls were studied simultaneously by conventional karyotype analysis and interphase FISH technique using SpectrumRed directly labeled DNA specific probe for 7q32. Two hundred interphase cells were analyzed for each case and the cells with one red hybridization spot<7% were regarded as positive. RESULTS: Three cases displayed -7/7q- by conventional cytogenetics(CC) and were confirmed by interphase FISH. Six cases in 43 cases who did not show -7/7q- by CC displayed -7/7q- by interphase FISH. CONCLUSION: Interphase FISH is very useful for the detection of -7 or 7q- in MDS and it is more sensitive than CC.

Adolescent↗

PubMed2001

[Relationship between methylenetetrahydrofolate reductase gene polymorphism and diabetic nephropathy].

OBJECTIVE: To investigate the relationship between methylenetetrahydrofolate reductase(MTHFR) gene polymorphism and diabetic nephropathy(DN). METHODS: The technology of polymerase chain reaction-restriction fragment length polymorphism(PCR-RFLP) was used to detect MTHFR gene C677T mutation in 85 healthy controls, 79 type-2 diabetics without DN, and 82 type-2 diabetics with DN confirmed by urine microalbuminous detection. RESULTS: The frequencies of MTHFR gene variant genotypes and alleles in the patients with DN patients were significantly higher than those in the patients without DN and those in healthy controls (P<0.01). CONCLUSION: MTHFR gene C677T mutation is probably one of the genetic risk factors for diabetic nephropathy in Chinese Hans.

Asian People↗

PubMed2001

[Treatment of the pyogenic infection of the thoracolumbar intervertebral space with vascular pedicled rib grafting].

OBJECTIVE: To investigate the effect of vascular pedicled rib grafting in treatment of the pyogenic infection of the thoracolumbar intervertebral space. METHODS: From November 1993, 7 cases with pyogenic infection of the thoracolumbar intervertebral space were adopted in this study. Among them, there were 5 males and 2 females, aged from 29 to 58 years old. The position of pyogenic infection located at T10 to 11 in 3 cases, at T11 to 12 in 2 cases and at T12 to L1 in 2 cases. During operation, the pyogenic infection was cleared completely and the rib with vascular pedicle was grafted into the intervertebral space. RESULTS: Followed up for 10 to 60 months, the bone graft unioned in 3 months for 5 patients and unioned in 4 months for 2 patients. There was no recurrence and raised kyphosis. CONCLUSION: The technique of vascular pedicled rib graft is simple, it can shorten the bone union time and reconstruct the stability of spine.

Adult↗

PubMed2001

[Detection of -5/5q- chromosome abnormality in myelodysplastic syndromes by interphase fluorescence in situ hybridization].

OBJECTIVE: To evaluate the value of interphase fluorescence in situ hybridization(FISH) in the detection of acquired complete and partial deletion of chromosome 5(-5/5q-) in myelodysplastic syndromes (MDS). METHODS: Marrow cells from 48 MDS patients and 10 normal controls were studied by interphase FISH using SpectrumRed directly labelled DNA specific probe for 5q31, 200 to 300 cells were scored for each case and cells with a red hybridization signal > 6% were defined as -5/5q- positive. RESULTS: In 48 MDS patients, 13 were positive for interphase FISH, of whom, 7 were positive and 6 were negative for conventional cytogenetics (CC). The difference in the percentage of positive cells detected by the two methods was statistically significant (P < 0.05). CONCLUSION: Interphase FISH is more sensitive than CC for the detection of -5/5q- in MDS.

Adult↗

PubMed2001

[Preliminary study on postremission therapy courses in acute myeloid leukemia].

OBJECTIVE: To explore the optimum postremission therapy courses in acute myeloid leukemia (AML). METHODS: Data from medical records of AML patients in our hospital in 7 year were analyzed with SPSS 8.0 system software. RESULTS: One hundred and ninety one untreated de novo AML patients received different induction chemotherapy regimens: HA, DA, AA and HAD. The complete remission (CR) rate was 81.4%, 89.9% for one to two courses. The median disease free survival (DFS) in 144 CR patients whose survival time could be analyzed was 9.6 months. The probability of survival was 21.6% at 3 year and 12.9% at 5 year. For the patients received less than 6 courses of post-remission therapy, the median DFS was 7.1 months and the probability of survival was 11.4% at 3 year and 6.3% at 5 years, Whereas for patients received 6 or more courses of post-remission therapy, they were 35.3 months, 43.2% and 27.0%, respectively. The differences between the two groups were statistically significant. For patients received 8 or more courses of post-remission therapy, the median DFS was 48.8 months and the probability of survival was 57.9% at 3 year and 31.6% at 5 year. CONCLUSION: AML patients should at least receive 6 courses of post-remission therapy, and 8 courses therapy seems better.

Acute Disease↗

PubMed2001

In vitro renaturation of recombinant human pro-urokinase expressed in Escherichia coli.

OBJECTIVE: Recombinant human pro-urokinase forms insoluble inclusion body when overexpressed in Escherichia coli. It must be denatured and renatured in vitro so that it can acquire activity. This study aimed at increasing the renaturation yield of denaturant pro-urokinase. METHODS: We evaluated the basic renaturation conditions of pro-urokinase through qualitative and quantitative analysis of pH, temperature, denatured concentration, protein concentration, and the ratio of reduced and oxidized thiol reagents. We also compared the effects of nonspecific additives, step-wise dilution and urea gradient dialysis. RESULTS: We defined the optimal conditions of pro-urokinase renaturation with a yield of about 20%-30%. CONCLUSION: Different recombinant denatured proteins have different renaturation conditions due to their different molecular sizes, molecular constructions, disulfide bond numbers, and hydrophobicity. The renaturation yield can be increased by optimizing the renaturation conditions of a specific protein.

Cysteine↗

PubMed2001

[Association between angiotensin-II receptor gene type I polymorphism and diabetic nephropathy in type 2 diabetes mellitus].

OBJECTIVE: To investigate the relationship between angiotensin type I receptor (AGT I R) gene polymorphism and diabetic nephropathy (DN) and its progression. METHODS: PCR technique was used to determine the AGT I R gene polymorphism in 86 patients without DN, 67 with microalbuminuria, 66 with clinical albuminuria and 20 type 2 DM patients with renal insufficiency. RESULTS: In comparing the DN group with the non-DN group, it was found that there was a significant difference of the frequency of AC genotype with DN (chi(2) = 4.30, P < 0.05), and C mutative type was more frequent in the DN group (chi(2) = 3.97, P < 0.05). No significant difference of AGTIR-A1166-C genotype was found in cases with different durations of DN. CONCLUSION: Delete polymorphism of A1166-C gene is associated with DN in type 2 diabetes mellitus. It is suggested that detection of significant AGTIR-A1166-C polymorphism is of help for preventing DN in type 2 diabetes mellitus.

Adult↗

PubMed2001

[The Immunophenotypical features of t (8; 21) (q22; q22) acute myeloid leukemia].

OBJECTIVE: To study the predictive value of immunophenotypical features in t (8; 21) (q22; q22) acute myeloid leukemia (AML). METHODS: Morphological/cytochemical, flow cytometric immunophenotyping, cytogenetic analyses (MIC) and RT-PCR were performed in 294 previously untreated AML. RESULTS: (1) In 294 AML patients, t (8; 21) AML were 21.8% (64); in AML-M(2), t (8; 21) AML were 54.7%; and in t (8; 21) AML, AML-M(2) were 81.3%. (2) Compared with control group, CD(19) and CD(34) expressions were higher, and CD(33) expression was lower (P < 0.001) in t (8; 21) AML. (3) If the cut-off value of CD(19) positive was >or= 20%, CD(19) positive rate was 13.6% (40/294) in AML, and 50% (32/64) and 3.5% (8/230) (P < 0.001) in t (8; 21) AML and control group. (4) CD(19)(+) and/or CD(34)(+) t (8; 21) AML accounted for 90.6% (58/64) of t (8; 21) AML and CD(19)(-)/CD(34)(-) for 9.6% (6/64). CONCLUSION: In t (8; 21) AML, especially M(2)/t (8; 21), CD(19) and CD(34) expressions were high. CD(19) was one of predictive markers of t (8; 21) AML.

Adolescent↗

PubMed2001

Expression and deletion analysis of EcoRII endonuclease and methylase gene.

OBJECTIVE: To clone complete EcoRII restriction endonuclease gene (ecoRIIR) and methyltransferase gene (ecoRIIM) in one vector and to analyze the coordinating expression of this whole R-M system. METHODS: Unidirectional deletion subclones were constructed with ExoIII. ecoRIIR/ M genes were preliminarily located in the cloned fragment according to the enzyme activities of subclones. Exact deletion sites were determined by sequencing, and transcriptional start sites were determined by S1 mapping. RESULTS: The DNA fragment which was cloned into pBluescript SK + contained intact ecoRIIR gene and ecoRIIM gene, and two transcriptional start sites of ecoRIIR gene were determined. 132bp to 458bp from 3'end of ecoRIIR gene are indispensable to enzyme activities and deletion of 202bp from 3' end of ecoRIIM gene made enzyme lose the capability in DNA protection to resist specific cut with EcoRII endonuclease (EcoRII. R). Deletion of the coding and flanking sequences of one gene did not affect the expression of the other gene, and the recombinants only containing ecoRIIR gene appeared to be lethal to dcm+ host. CONCLUSION: ecoRIIM gene linking closely to ecoRIIR gene is very important for the existence of the R-M system in process of evolution, but the key to control EcoRII R-M order may not exist in transcriptional level .

Base Sequence↗