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Biomedical subjects

Y Xue

Publications and source records attributed to Y Xue.

At least 163 records · Page 9Linked to original sources
PubMed1997

[Antiarrhythmic effects of DHA-As on ventricular arrhythmias in rat and dog hearts].

DHA-Ascorbic acid (DHA-As), a new derivative of docosahexaenoic acid (DHA) was tested for its possible antiarrhythmic effects on coronary artery ligation/reperfusion arrhythmias in rat hearts, and adrenaline-induced arrhythmias in canine hearts. DHA-As (3 mg/kg i.v.) did not change the total duration of VT, and tended to suppress the incidence of VT, VF and mortality of reperfusion in rat hearts. The heart rate, QT90 and systolic blood pressure did not change, and the diastolic blood pressure was decreased by DHA-As in the rat hearts. DHA-As significantly decreased the arrhythmic ratio only at two time points (14 and 15 min after injection), and also decreased the heart rate and mean blood pressure in canine hearts. In conclusion, DHA-As tended to suppress the reperfusion-induced arrhythmias in rat hearts. However, the change was not statistically significant. In addition, DHA-As has a weak suppressing effect on adrenaline-induced arrhythmia.

Animals↗
PubMed1997

[The methylation of CT gene in chronic myeloid leukemia].

To investigate the relationship between the abnormal methylation of the calcitonin (CT) gene and the karyotypic abnormality in predicting the disease progress in chronic myeloid leukemia (CML), we studied the abnormal methylation of the CT gene in 47 CML patients by using a sensitive PCR method. At the same time, cytogenetic study was made in the same group of patients. The abnormal methylation of CT gene was found in only 4 of 24 patients in chronic phase, but in 6 of 9 patients in accelerated phase, and in 12 of 14 patients in blast crisis. Sequential studies in one patient also showed that the gene is normally methylated during the chronic phase but turns hypermethylated as the disease progresses. Our findings indicate that abnormal methylation of the 5' region of the CT gene is regularly a marker of disease progression in CML.

Adolescent↗
PubMed1997

[Chromosomal abnormalities and their clinical significance in acute lymphoblastic leukemia in adults].

To determine the chromosomal abnormalities and their clinical significance in adult acute lymphoblastic leukemia, karyotypic analyses with R- and/or G-banding were performed in 101 newly diagnosed ALL patients. The results showed that 69 (68.32%) cases had clonal chromosomal abnormalities and specific abnormalities including Philadelphia chromosome (32.67%), t(4;11) (2.97%), t(11;14) (3.96%), abnormalities of 8q24 (2.97%), 6q- (4.96%). Patients with Ph chromosome showed higher leukocyte counts and more frequent hepatosplenomegaly and most of them were L2 and B lineage subtypes. They had lower complete remission (CR) rate, needed longer time to achieve CR and relapsed earlier as compared with patients without Ph chromosome. These suggested that chromosomal abnormalities are very frequent and some specific abnormalities had specific clinical features.

Adolescent↗
PubMed1997

[Preliminary study on method for predicting lower body negative pressure tolerance].

To find out a method to predict lower body negative pressure (LBNP) tolerance with noninvasive physiological measurements, 11 healthy young subjects were tested in an LBNP chamber in sitting position. Incremental negative pressure was used for evaluating LBNP tolerance time. End points of the test were onset of presyncopal symptoms or completion of 15 min test. According to their reactions, the 11 subjects were divided into good tolerance group (group A, n = 5) and poor tolerance group (group B, n = 6); At the 11th minute of LBNP, mean arterial pressure (MAP), magnitude of decrease of regional cerebral oxygen saturation (delta SrO2) and cardiac output (delta CO) showed significant difference between group A and B(P <0.05); Mean error was 0.54 +/- 0.42 min when LBNP tolerance was predicted using MAP and delta SrO2 at this moment by regression analysis.

Aerospace Medicine↗
PubMed1997

Changes of cerebral oxygen saturation under lower body negative pressure.

The purpose of this study was to observe and analyse the changes of regional cerebral oxygen saturation (SrO2) under lower body negative pressure (LBNP). 12 healthy young subjects were tested in an LBNP chamber in sitting position. Incremental negative pressure was used and end points of test were onset of presyncopal symptoms or completion of the 15min test. The results were: (1) SrO2 showed a significant decrease under LBNP; (2) The magnitude of decrease of SaO2 showed significant differences among subjects with different reactions at the termination of LBNP; (3) Under LBNP the arterial oxygen saturation (SrO2) kept constant. The changes of SrO2 correlated strongly with the percentage changes of superaorbitalis arterial blood flow (r = 0.59-0.86, P < 0.05 or 0.01). It was suggested that the changes of SrO2 were related to the decrease of cerebral blood flow under LBNP. It was possible to use SrO2 to detect presyncopal and syncopal symptoms. So the monitoring of SrO2 could be used in studies of G-LOC.

Adult↗
PubMed1997

[The prognostic significance of regular bone marrow aspirations during induction chemotherapy in acute myeloid leukemia].

OBJECTIVE: To evaluate the prognostic significance of regular aspirations during induction chemotherapy in acute myeloid leukemia. METHODS: Regular bone marrow aspirations were performed during the first course of induction chemotherapy in 96 cases of de novo AML. RESULTS: Complete remission (CR) rate after the first course in patients with < or = 0.10 bone marrow blasts at the 7th day on chemotherapy was higher than that in patients with > 0.10 blasts (64.6% vs 40.0%, P < 0.05). Prolonged the chemotherapy course for a few more days in the latter group of patients increased CR rate from 25.0% to 50.0%. CR rate in patients with < or = 0.10 bone marrow blasts at the nadir of white blood cell count after chemotherapy was higher than that in patients with > 0.10 blasts (66.0% vs 25.8%, P < 0.005), and the refractory cases were significantly fewer in the former group of patients (7.5% vs 45.2%, P < 0.005). CONCLUSION: Regular bone marrow aspirations during induction chemotherapy were helpful in predicting the prognosis and guiding the treatment in AML.

Adolescent↗
PubMed1997

[Tetraploid clones characterized by double 8;21 translocations in two patients with acute myeloid leukemia].

OBJECTIVE: To report two cases of leukemia with t(8;21) and tetraploid clones. METHODS: R-banding technique was used. RESULTS: Cytogenetic studies of BM cells at diagnosis revealed that each of the two cases had three related abnormal clones besides a normal one: 46, XY, t(8;21) (2%), 46, idem, add((7)(q31)(6.8%) and 92, idem x 2 (80.6%) in case 1 and 46, XX, t(8;21) (13.4%), 47, idem, + 4 (46.3%) and 94, idem x 2 (39.1%) in case 2. They did not obtain complete remission on chemotherapy and survived 4 and 6 months, respectively. CONCLUSION: Tetraploid or near tetraploid clones are secondary events which are specifically associated with t(8;21) leukemia and the prognosis of patients with this kind of abnormal karyotype is poor.

Adult↗
PubMed1997

[Determination of icariin in Epimedium koreanum nakai by high performance liquid chromatography].

An HPLC method for determination of icariin in epimedium koreanum nakai was investigated. The results showed that this method was simple, specific and accurate. The recovery was 97.6% and relative standard deviation was 1.2%. About 0.5 g of dried powdered crude drug was weighed accurately, placed in 25 mL of the mobile phase and refluxed on a water-bath for 30 min. After cooling, the solution was decanted. The residue was refluxed twice with 10 mL of the mobile phase. The extract were placed in a 50 mL volumetric flask and diluted to 50 mL with the mobile phase. A 3 microL of the solution was injected into the HPLC system. Linear calibration graphs for icariin were obtained for the concentration ranges of 0.08-0.4 microg. HPLC conditions were used was Shimadzu LC-6A with UV spectrometric detector SPD-6AV; at 270 nm and auto injector SIL-6A. Water-acetonitrile (70:30) as the mobile phase, Shim-pack CLC-ODS column (6.0 mm x 150 mm).

Chromatography, High Pressure Liquid↗
PubMed1997

Changes in keratin expression during the development of benign prostatic hyperplasia.

OBJECTIVE: The relationship between different types of epithelial cells in the prostate and the regulatory mechanism underlying benign prostatic hyperplasia (BPH) are still obscure as is the association between BPH and prostate carcinoma (PCa.) On the basis of keratin immunophenotyping, a subpopulation of cells in normal rat prostate and human PCa have been identified as candidates for the 'amplifying cell' in the stem cell model. In this model the basal cell is described as being associated with the stem cell. From this precursor an intermediate cell type develops which may differentiate into the luminal-type cell. In this study these different cell types are investigated in the development of isolated BPH and BPH associated with PCa, using monoclonal antibodies to intermediate filaments of the keratin class. METHODS: We immunohistochemically stained 64 snap-frozen human prostatic tissues, using monoclonal antibodies against keratin 14 (marker for putative 'stem cell'), keratin 18 (marker for putative 'transit cell'), and MAb RCK103 (marker for putative 'amplifying cell' or intermediate cell). RESULTS: In basal cell hyperplasia, an atypical form of BPH, keratins previously associated with intermediate cells were frequently detected. Cells with this keratin phenotype were detected in the luminal compartment of BPH, and were more prevalent in BPH adjacent to PCa. This keratin expression pattern was similar to that of PCa. CONCLUSION: On the basis of keratin phenotyping we demonstrated that large numbers of cells with the keratin expression pattern of so-called intermediate cells were identified in BPH associated with PCa, while in isolated BPH these cells were infrequently found. This supports the concept that BPH with intermediate phenotype may have premalignant potential. Furthermore this is suggestive of an etiologic relationship between the two diseases.

Antibodies, Monoclonal↗
PubMed1997

Prostatic neuroendocrine cells have a unique keratin expression pattern and do not express Bcl-2: cell kinetic features of neuroendocrine cells in the human prostate.

We investigated the keratin phenotype and bcl-2 immunoreactivity of neuroendocrine cells in the human prostate to determine whether the postmitotic status of these cells is associated with protection from apoptosis by bcl-2 protein expression and to elucidate the possible cell kinetic relationship between neuroendocrine cells and the other epithelial components of the prostate. Tissue specimens were selected from prostates of 19 patients harboring normal secretory glands (n = 15) and glandular benign prostatic hyperplasia (n = 10). Using a novel sequentially selective destaining immunoenzymatic cytochemical technique we were able to demonstrate the distribution of neuroendocrine cells, keratin markers identifying either basal, luminal, or intermediate cells, and the bcl-2 protein in single sections. Basal cell keratins were expressed in the minority of the neuroendocrine cells. In most of the cells, intermediate and luminal cell keratins were found and bcl-2 was constantly negative. Our findings indicate that neuroendocrine cells and other epithelial cells in the human prostate share a common keratin phenotype and probably originate from a common epithelial precursor. From the absence of bcl-2 we infer that the neuroendocrine cells have no progenitor cell characteristics.

Aged↗
PubMed1997

[Cloning and expression of promoter and signal peptide function fragments from Lactococcus lactis in Escherichia coli].

Promoter and signal peptide function fragments from Lactococcus lactis were cloned in E. coli using a promoter-signal sequence probe vector pGPB14. Forty-two clones were obtained, whose level of resistance to ampicillin ranged from 100 to 8000 micrograms/ml. Eight clones were selected for beta-lactamase distribution assay. The beta-lactamase activity was found mainly in the periplasm, which indicated successful secretion of the enzyme. Southern hybridization test demonstrated that the inserted fragments were indeed from L. lactis. Restriction enzyme analysis revealed that the size of inserted fragments ranged from 80bp to 400 bp, four of which were sequenced on the vector pGEM-3Zf. It was found that the inserted fragments of pSEQ8 and pSEQ12 turned out to be part of the inserted fragments of pSEQ4 and pSEQ17 respectively. Promoter and translation initiation codon were found among all four fragments signal sequenced. One typical S. D. sequence and one atypical signal sequence were found in pHSB4 and pHSB8, while the other two contained no typical S. D. sequence and signal peptide sequence. In addition, it was found that the upstream regions of the promoter contributed to the efficiency of transcription initiation.

Base Sequence↗
PubMed1997

High-level expression and purification of human pro-UK cDNA in Escherichia coli.

A chemically synthesized human pro-urokinase (pro-UK) CDNA was cloned into the expression vector PET-11d and expressed in E. coli BL21(DE3) pLysS under the control of the T7 promoter. Using 0.1 mmol/L IPTG induction, the expression level of the recombinant pro-UK attained up to 15% of the total bacterial proteins and existed as inclusion bodies. After denaturation and renaturation in vitro, the expressed pro-UK was purified to be identified by Zn2+ selective precipitation, immuno-affinity chromatography, and benzamidine affinity adsorption. The specific activity of the purified human pro-UK was about 110,000 IU/mg.

Cloning, Molecular↗
PubMed1997

[Immunophenotypic and clinical features of Philadelphia chromosome positive adult lymphocytic leukemia].

OBJECTIVE: To sutdy the immunophenotypic and clinical features of Philadelphia chromosome positive adult acute lymphocytic leukemia (Ph+ ALL). METHODS: Fifty-one previously untreated Ph+ ALL were included. Morphologic/cytochemistric, cytogenetic and immunophenotypic examinations were performed. Patients received daunorubicin-vincristine-prednisone (DOP) or DOP-asparaginas (DOLP) induction protocols. Two patients received autologous bone marrow transplantation (ABMT) as postremission therapy. RESULTS: The 51 patients were among 158 patients with ALL (32.3%). Patients with Ph+ ALL were older and had a significantly higher incidence of peripheral leukocytosis and blasts, FAB L2 subtype, B lineage antigens expression and CD34 positivity. 42.1% of Ph+ ALL achieved complete remission (CR). Their remission duration was 4.5 months, the median time to CR was 54 days. Two patients receiving ABMT survived in remission 22 and 33 months, respectively. CONCLUSION: Patients with Ph+ ALL are usually older, have FAB L2 morphology, and are B lineage antigens, CD34 positive. These patients had lower CR rate, shorter remission duration, and needed longer time to achieve CR.

Adult↗
PubMed1997

[Inhibition of angiogenesis by antitumor antibiotic C1027 and its effect on tumor metastasis].

OBJECTIVE: To investigate the effect of C1027, an enediyne antitumor antibiotic, on angiogenesis and its anti-metastatic activity. METHODS: Chick embryo chorioallantoic membrane assay was used for anti-angiogenesis activity and bFGF receptor binding assay was used for the elucidation of the possible mechanism. Spontaneous pulmonary metastasis of Lewis carcinoma in mice was employed to evaluate the anti-metastatic effect. RESULTS: C1027 was highly potent in suppressing angiogenesis with a minimum effective dose of 0.01 microgram/egg. Enediyne chromophore moiety of the C1027 molecule was essential to anti-angiogenesis activity. Receptor binding assay showed that C1027 blocked bFGF binding to its receptor with an IC50 value of 2.3 x 10(-6) micrograms/ml. C1027 markedly inhibited pulmonary metastasis of Lewis carcinoma in mice. Compared at equitoxic dosage level (1/4 LD50), C1027 (0.01 mg/kg, i.v., x 2) was more effective than mitomycin (1.25 mg/kg, i.v., x 2) and the percent inhibition of metastatic foci in the lung was 98% and 78%, respectively. CONCLUSIONS: C1027 is a new potent anti-angiogenesis agent with markedly anti-metastatic activity. The mechanism of C1027 suppressing angiogenesis may be related to its blocking effect on bFGF binding to its receptor.

Aminoglycosides↗
PubMed1996

Sensitive capillary gas chromatographic-mass spectrometric-selected-ion monitoring method for the determination of diclofenac concentrations in human plasma.

We have modified and validated a capillary GC-MS method reported by Kadowaki et al. [J. Chromatogr., 308 (1984) 329] for the determination of diclofenac in human plasma by using heptane rather than benzene as an extraction agent. In addition, acetone was added to the samples as a deproteination agent which increased the recovery of diclofenac. These revised processes allowed clean extraction and near-quantitative recovery of analyte (> 95%). Separation was achieved on an HP-1 column with helium as carrier gas. The parent ion peaks of diclofenac (m/z 277) and the internal standard, 4'-methoxydiclofenac (m/z 307), were monitored by a mass-selective detector using the selected-ion monitoring mode. The linear range for the routine assay was from 5 to 2000 ng/ml. The detection and lower quantifiable limits were 0.2 and 1 ng/ml, respectively, with no interference from plasma. The within-day and between-day coefficients of variation for high and medium concentrations were less than 5% and were less than 13% for low concentrations (10 ng/ml). This GC-MS assay method has been used for pharmacokinetic and drug interaction studies in humans.

Acetone↗
PubMed1996

Purification and biochemical heterogeneity of the mammalian SWI-SNF complex.

We have purified distinct complexes of nine to 12 proteins [referred to as BRG1-associated factors (BAFs)] from several mammalian cell lines using an antibody to the SWI2-SNF2 homolog BRG1. Microsequencing revealed that the 47 kDa BAF is identical to INI1. Previously INI1 has been shown to interact with and activate human immunodeficiency virus integrase and to be homologous to the yeast SNF5 gene. A group of BAF47-associated proteins were affinity purified with antibodies against INI1/BAF47 and were found to be identical to those co-purified with BRG1, strongly indicating that this group of proteins associates tightly and is likely to be the mammalian equivalent of the yeast SWI-SNF complex. Complexes containing BRG1 can disrupt nucleosomes and facilitate the binding of GAL4-VP16 to a nucleosomal template similar to the yeast SWI-SNF complex. Purification of the complex from several cell lines demonstrates that it is heterogeneous with respect to subunit composition. The two SWI-SNF2 homologs, BRG1 and hbrm, were found in separate complexes. Certain cell lines completely lack BRG1 and hbrm, indicating that they are not essential for cell viability and that the mammalian SWI-SNF complex may be tailored to the needs of a differentiated cell type.

Amino Acid Sequence↗
PubMed1996

Diversity and specialization of mammalian SWI/SNF complexes.

The SWI/SNF complex in yeast facilitates the function of transcriptional activators by opposing chromatin-dependent repression of transcription. We demonstrate that in mammals SWI/SNF complexes are present in multiple forms made up of 9-12 proteins that we refer to as BRG1-associated factors (BAFs) ranging from 47 to 250 kD. We have isolated cDNAs for human BAF155, BAF170, and BAF60. BAF155 and BAF170 are encoded by separate genes that are both homologs of yeast SWI3. Both contain a region of similarity to the DNA binding domain of myb, but lack the basic residues known to be necessary for interaction with DNA. The two SWI3 homologs copurify on antibody columns specific for either BAF155 or BAF170, indicating that they are in the same complex. BAF60 is encoded by a novel gene family. An open reading frame from yeast, which is highly homologous, encodes the previously uncharacterized 73-kD subunit of the yeast SWI/SNF complex required for transcriptional activation by the glucocorticoid receptor (Cairns et al., this issue). BAF60a is expressed in all tissues examined, whereas BAF60b and BAF60c are expressed preferentially in muscle and pancreas, respectively. BAF60a is present within the 2000-kD BRG1 complex, whereas BAF60b is in a distinct complex that shares some but not all subunits with the BRG1 complex. The observed similarity between mammalian BAF190, BAF170, BAF155, BAF60, and BAF47 and yeast SNF2/SWI2, SWI3, SWI3, SWP73, and SNF5, respectively, underscores the similarity of the mammalian and yeast complexes. However, the complexes in mammals are more diverse than the SWI/SNF complex in yeast and are likely dedicated to developmentally distinct functions.

Amino Acid Sequence↗