Biomedical subjects

Y Xue

Publications and source records attributed to Y Xue.

At least 109 records · Page 6Linked to original sources

PubMed1999

Protein kinase C activation increases binding of transcription factor PU.1 in murine tissue macrophages.

PU.1 is a transcription factor found in macrophages, B cells, neutrophils, and hemopoietic stem cells. In macrophages PU.1 regulates a number of genes, including c-fms, CD11b, CD18, and FcgammaR1b. Previously, in primary macrophages PU.1 binding to the sequence GAGGAA was found to be induced by treatment with bacterial lipopolysaccharide (LPS) and interferon-gamma (IFN-gamma). Here we investigated the role of protein kinase C (pKC) in the induction of PU.1 binding in macrophages. We report that pharmacological activation of pKC increases PU.1 binding, while inactivation of pKC inhibits the increases in PU.1 binding by agents which activate pKC in macrophages (LPS and tumor necrosis factor-alpha), but not by an agent which does not activate pKC (IFN-gamma). pKC activation may therefore be one pathway by which PU.1 binding may be increased in primary macrophages.

Animals↗

PubMed1999

Transient tenascin enhancement is an early event after androgen ablation in rat prostate.

Tenascin (tenascin-C), a mesenchymal glycoprotein, is expressed in many tissue remodeling processes. We evaluated tenascin expression during androgen-deprivation-related involution of the rat prostate. At set intervals following castration and subsequent testosterone repletion, prostates were removed in 30 adult rats. Each prostate was immunostained with a polyclonal antiserum against rat tenascin and keratin antibodies specifically directed against exocrine basal cells and luminal cells in the prostate glandular structure. Morphologic impressions were semiquantatively evaluated using a computer-assisted image analysis system. Rat prostates showed a transient increase in the periglandular tenascin expression directly following castration that reached a maximum at day 3. At day 6, tenascin expression was similar to control prostates. This was accompanied by a decrease of cells in the luminal cell layer. The weakest tenascin immunoreactivity was noted on day 14 after androgen withdrawal. This process was reversed by androgen repletion. This study shows that in the rat prostate tenascin expression may be androgen dependent and that during androgen deprivation-related involution tenascin expression is probably associated with tissue remodeling by stromal-epithelial interactions.

Androgens↗

PubMed1999

Embryonic lethality and vascular defects in mice lacking the Notch ligand Jagged1.

The Notch signaling pathway is an evolutionarily conserved intercellular signaling mechanism essential for embryonic development in mammals. Mutations in the human JAGGED1 ( JAG1 ) gene, which encodes a ligand for the Notch family of transmembrane receptors, cause the autosomal dominant disorder Alagille syndrome. We have examined the in vivo role of the mouse Jag1 gene by creating a null allele through gene targeting. Mice homozygous for the Jag1 mutation die from hemorrhage early during embryogenesis, exhibiting defects in remodeling of the embryonic and yolk sac vasculature. We mapped the Jag1 gene to mouse chromosome 2, in the vicinity of the Coloboma ( Cm ) deletion. Molecular and complementation analyses revealed that the Jag1 gene is functionally deleted in the Cm mutant allele. Mice heterozygous for the Jag1 null allele exhibit an eye dysmorphology similar to that of Cm /+ heterozygotes, but do not exhibit other phenotypes characteristic of Cm /+ mice or of humans with Alagille syndrome. These results establish the phenotype of Cm /+ mice as a contiguous gene deletion syndrome and demonstrate that Jag1 is essential for remodeling of the embryonic vasculature.

Animals↗

PubMed1999

Paracrine glucocorticoid activity produced by mouse thymic epithelial cells.

Previous data have suggested that glucocorticoids (GCs) are involved in the differentiation of thymocytes into mature T cells. In this report we demonstrate that the mouse thymic epithelial cells (TEC) express the cytochrome P450 hydroxylases Cyp11A1, Cyp21, and Cyp11B1. These enzymes, in combination with 3beta-hydroxysteroid dehydrogenase (3betaHSD), convert cholesterol into corticosterone, the major GC in rodents. In addition, when TEC were cocultured with 'reporter cells' containing the glucocorticoid receptor (GR) and a GR-dependent reporter gene, a specific induction of reporter gene activity was observed. Induction of reporter gene activity was blocked when the TEC and reporter cells were incubated in the presence of the Cyp11B1 inhibitor metyrapone or the 3betaHSD inhibitor trilostane, as well as by the GR antagonist RU486. Coculturing of TEC with thymocytes induced apoptosis in the latter, which was partially blocked by the enzyme inhibitors and RU486. We conclude that TEC secrete a GC hormone activity and suggest a paracrine role for this in thymocyte development.

3-Hydroxysteroid Dehydrogenases↗

PubMed1999

Absence of the derived allele at the DYS199 locus in 3 NE Chinese populations.

The allelic states of DYS199 locus were studied by allele-specific PCR. We found that all of the 107 samples chosen from three populations of northeast China had DYS199 C alleles. The result excluded the possibility that this mutation first identified in native American populations came from the three populations of northeast China.

Alleles↗

PubMed1999

Isolated tetrasomy 8 in minimally differentiated acute myeloid leukemia (AML-M0).

Tetrasomy 8 as a sole anomaly in hematological disorders is relatively rare. To the best of our knowledge, only 19 such cases have been described in the literature to date. Of them, acute myeloid leukemia (AML) in 13 (M1, one; M2, three; M4, one; M5, eight), acute lymphoblastic leukemia(ALL) in one, myelodysplastic syndrome(MDS) in 3, polycythemia vera(PV) and myelofibrosis(MF), one case each. Their median survival was 20 weeks. Here, we report the first case of a 29-year-old man with minimally differentiated AML (AML-M0) displaying a tetrasomy 8 clone. Immunophenotyping showed positivity with CD33, CD34 and intracellular MPO, but all lymphoid markers tested were negative. Conventional cytogenetics of bone marrow cells showed 84.9% of metaphases with tetrasomy 8 in addition to 15.1% with normal diploidy. However, Fluorescence in situ hybridization(FISH) using a centromeric probe specific for chromosome 8 revealed trisomy 8 in 14.2% of interphase nuclei besides tetrasomy 8 in 82.4%. The patient died four weeks after diagnosis without therapy. In conclusion, these findings suggest that tetrasomy 8 is associated with a heterogeneous group of myeloid disorders and heralds a bad prognosis. It may be a consequence of clonal evolution of trisomy 8.

Acute Disease↗

PubMed1999

Human Müller cells express VEGF183, a novel spliced variant of vascular endothelial growth factor.

PURPOSE: Vascular endothelial growth factor (VEGF) is a potent angiogenic factor expressed as multiple RNA transcripts due to alternative splicing. During an investigation of the expression of VEGF mRNA in human Müller cells cultured under hypoxic conditions, a cDNA species was isolated whose size was incompatible with known VEGF transcripts. This study was performed to determine the nucleotide sequence of the candidate VEGF species and examine the effects of hypoxia on its expression. METHODS: Cultured human Müller cells were exposed to normoxic (20% O2, 5% CO2, 75% N2) or hypoxic (2% O2, 5% CO2, 93% N2) conditions at 37 degrees C for 4 hours and processed for reverse transcription-polymerase chain reaction (RT-PCR), molecular cloning, Southern hybridization, nucleotide sequencing, semiquantitative RT-PCR, and ribonuclease protection assay. RESULTS: The nucleotide sequence of the novel VEGF species isolated from human Müller cells had a short exon 6-encoded sequence without 18-bp nucleotides immediately upstream of the exon 7-encoded sequence in VEGF189. The 18-bp deletion (corresponding to the six amino acids Tyr-Lys-Ser-Trp-Ser-Val) was compatible with a polypeptide containing 183 amino acids (VEGF183). Although VEGF183 mRNA was found in all tissues studied, its expression seemed to be higher than that of VEGF 189 in the brain and spleen; lower in the kidney, retina, skeletal muscle, and liver; and at similar level in the heart. Exposure to hypoxic conditions for 4 hours promoted increased levels of VEGF mRNA including that of VEGF183. CONCLUSIONS: The expression of the novel isoform VEGF 183 in human Müller cells, its variable tissue expression, and its modulation by hypoxia may provide another pathway for VEGF induction of angiogenesis in the retina.

Alternative Splicing↗

PubMed1999

Combination of all-trans retinoic acid with butyric acid and its prodrugs markedly enhancing differentiation of human acute promyelocytic leukemia NB4 cells.

OBJECTIVE: To use NB4, an authentic human acute promyelocytic leukemia cell line, as well as the marrow cells from patients with acute promyelocytic leukemia (APL), containing the PML/RAR alpha fusion gene and fused protein to examine the growth inhibition and cytodifferentiation induced by all-trans retinoic acid (ATRA), butyric acid (BA) and its prodrug tributyrin (TB) either as a single agent or in combinations. METHODS: NB4 and APL cells were cultured in presence of ATRA, BA and TB respectively either as a single agent or in combinations at various concentration ratio. Cell growth was measured and myeloid differentiation was determined by morphology and the percentage of positive nitroblue tetrazolium reduction (NBT) on consecutive days over the whole process of culture. RESULTS: NB4 cells can be induced by ATRA alone and synergistically induced by the combinations of BA or TB with ATRA to differentiate. The synergy was reflected by a remarkable decrease in the effective concentration of ATRA required in the combinations in comparison with it as a sole agent. The combinations also shortened the time for the cells to reach the same level of maturation as that needed for ATRA alone. The potentiation on ATRA-induced differentiation of NB4 cells seemed depending on an appropriate concentration ratio of each inducer in the combinations and the time of action. A preliminary result of in vitro induction of primarily cultured leukemic cells from APL patients by the combined inducers was promising. CONCLUSION: The combinations of ATRA with BA or TB at an appropriate ratio may improve the clinical outcome of differentiation therapy for APL patients.

Butyric Acid↗

PubMed1999

Proliferative activity in cervical intraepithelial neoplasia and cervical carcinoma.

OBJECTIVE: To detect the proliferative activity of cervical cells in cervical intraepithelial neoplasia (CIN) and cervical carcinoma by using proliferating cell nuclear antigen (PCNA) immunohistochemistry and mitotic index (MI). METHODS: Sixty specimens of CIN and cervical carcinoma from patients treated at the Obstetrics and Gynaecology Hospital, Shanghai Medical University, were analyzed. Among them, 8 were CIN I-II, 16 CIN III, 18 squamous carcinoma, and 18 adenocarcinoma. Serial 4 microns sections were prepared for haematoxylin and eosin (HE) staining to observe mitotic figure and pathological grading and for immunohistochemical staining of PACN which was performed by murine monoclonal antibody PC 10 (DAKO-PCNA). RESULTS: PCNA index (PI) and MI of CIN III and cervical carcinoma were significantly higher than those of normal cervix and CIN I-II. PI and MI increased with progress of disease. In addition, higher level of PI was correlated with higher level of MI, and higher levels of PI and MI were related with higher histological grade. However, there was no significant relationship between PI, MI, clinical staging, and lymph node metastases. CONCLUSION: PCNA and mitotic figure are useful for evaluating proliferative activity in CIN and cervical carcinoma, and could be used to distinguish CIN III from CIN I-II and evaluate the malignant potential of tumour tissues.

Adenocarcinoma↗

PubMed1999

Urinary cross-linked N-telopeptides of type I collagen and bone metabolic diseases.

OBJECTIVE: To evaluate the type I collagen cross-linked N-telopeptide (NTx) levels in human urine as an indicator of bone resorption rate in different ages, sex and in bone metabolic diseases. METHODS: Urinary NTx was determined by immunoassay in 591 Beijing healthy subjects aged from 0 to 86 years and 379 patients with bone metabolic diseases. RESULTS: The levels of urinary NTx were significantly higher in children than in adults (P < 0.001) and higher in boys than in girls (P < 0.01) and increased 1.4-2.2 times in postmenopausal females than in men and premenopausal women. Urine NTx had a positive linear correlation with urine HOP/Cr (r = 0.778, P < 0.01) and Ca/Cr ratio (r = 0.320, P < 0.01), and a negative linear correlation with age (r = -0.523, P < 0.01) and lumbar spine BMD (r = -0.426, P < 0.01). The levels of urine NTx increased for 3.6 times in pregnancy, 1.5 times in osteoporosis, 1.9 times in fragility fracture, 3.6 times in chronic renal failure, 2.1 times in rickets and 7.2 times in multiple myeloma compared to age matched controls. CONCLUSIONS: NTx in urine is a specific and sensitive indicator of bone resorption and is able to distinguish normal premenopause from late osteoporotic patients. NTx could be used as diagnostic information about metabolic bone diseases, and to monitor antiresorptive therapy.

Adolescent↗

PubMed1999

[Expressions of cellular M-CSF and M-CSFR in hematopoietic cells].

OBJECTIVE: To study the distribution of cellular M-CSF and its receptor in abnormal hematopoiesis. METHODS: Six hematopoietic cell lines, 144 bone marrow (BM) and 160 peripheral blood (PB) samples were investigated with ABC immunoperoxidase assay. RESULTS: Cellular M-CSF and/or M-CSFR were positive in all the 6 hematopoietic cell lines, a few normal BM(4 cases) and PB (32 cases) samples, hematological malignancies and a few benign hematological disorder samples. M-CSF and M-CSFR were found mainly in granulocytic lineage cells, seldom in erythroid and megakaryocytic lineage cells and never in lymphocytes. M-CSF and M-CSFR usually presented in cytoplasma and membrane and in some cases in nuclei. CONCLUSION: Cellular M-CSF and M-CSFR is widely distributed in abnormal hematopoiesis, and is especially high in myeloid leukemias.

HL-60 Cells↗

PubMed1999

Modulation of in vivo granuloma formation related to regulation of in vitro IFN-gamma and IL-4 expressions in experimental schistosomiasis japonica.

OBJECTIVE: To find out relationship between the in vitro schistosome egg antigen (SEA) stimulated IFN-gamma and IL-4 mRNA expressions and the in vivo SEA elicited granulomatous responses, the transcriptions of IFN-gamma and IL-4 gene were investigated in the spleen of BALB/c mice infected with Schistosoma japonicum (S. japonicum). METHODS: Spleens were removed at 0, 3, 5, 8, and 10 and 12 weeks after infection and the spleen cells were incubated in the presence of SEA. The extracted RNA was analyzed for IFN-gamma and IL-4 mRNA by reverse transcription PCR (RT-PCR). Newly-formed liver granulomas were measured. RESULTS: The study revealed that no detectable IFN-gamma and IL-4 mRNA RT-PCR products were found in SEA treated spleen cells from uninfected, or 3-week infected mice, whereas IL-4 mRNA was found to be expressed in 5- and 8-week infected mice, and an appreciable enhanced expression of IL-4 mRNA was observed in SEA stimulated spleen cells at 8-week infection than at 5-week infections. However, SEA could not induce IFN-gamma and IL-4 mRNA transcription in 10- and 12-week infected mice, indicating the modulated expression of IFN-gamma and IL-4 mRNA. CONCLUSION: The significant changes of IL-4 mRNA expression in SEA stimulated spleen cells during S. japonicum infection were coincident with SEA elicited granuloma formation and modulation in vivo.

Animals↗

PubMed1999

[The comparison of bone densities of mandible and coxofemoral region between senile people with edentulous jaws and those with dentate jaws].

OBJECTIVE: To observe if the senile people with edentulous jaws had lower bone dentilies of mandible and coxofemoral region than those with dentate jaws, and to find the systemic risk factors which were responsible for the tooth loss and the formation of edentulous jaws. METHODS: Two groups of senile people were selected. One group was edentulous and the other was dentate. All of them were examined by dual energy X-ray absorptiometry(DXA). RESULTS: The senile people with edentulous jaws had significantly lower bone densities of mandible(P < 0.001) and they also had lower bone densities of coxofemoral region than the dentate group people. CONCLUSION: It indicated that the decreased of bone densities of mandible and coxofemoral region was one of the systemic risk factors for tooth loss and the formation of edentulous jaws.

Age Factors↗

PubMed1999

[Effect of tongxinluo capsule in treating variant angina pectoris patients and its influence on endothelial function].

OBJECTIVE: To assess the efficacy of Tongxinluo capsule (TXLC) in treating variant angina pectoris and its effect on endothelial function. METHODS: Sixty-four patients with variant angina pectoris were enrolled in the study for four weeks by a randomized clinical trial treatment with TXLC or isosorbide mononitrate. RESULTS: (1) The symptoms of both groups were significantly improved, the total effective rate of TXLC and isosorbide were 86.67% and 87.10% respectively; (2) The level of serum nitric oxide was increased, and the serum endothelin was decreased after treatment, there was no significant difference between these two groups. CONCLUSION: TXLC could effectively improve the symptoms of variant angina pectoris, the mechanism of which may likely be mediated by nitric oxide and endothelin.

Adult↗

PubMed1999

[Enhancing effect of Chinese herbal medicine mixture on peripheral blood lymphocyte proliferation and interleukin-2 production in patients of burn].

OBJECTIVE: To study the regulatory effect of Chinese herbal medicine mixture (CHMM) on cell-mediated immune function in patients of burn. METHODS: Patients of burn were treated with CHMM and the therapeutic effect was evaluated by their peripheral blood T-lymphocyte (PBL) proliferation and interleukin-2 (IL-2) production determination. RESULTS: The PBL proliferation began to increase after 5 days of medication and the response was significant between the 10th to 20th day, which was in accordance with the change of IL-2 production. CONCLUSION: CHMM has immune regulatory effect on cell-mediated immune function in patients of burn.

Adjuvants, Immunologic↗

PubMed1999

[Effect of physiological dosage of estrogen on the prevention of bone loss in rats induced by ovariectomy].

The effect of small dosage of 17 beta-estradiol (E2) on bone metabolism, bone mineral density (BMD) and biomechanical properties of bone in ovariectomized rats were observed. Twenty-one rats were divided into three groups. They were sham-operated group (A), ovariectomized group (B), and ovariectomized and treated with 17 beta-estradiol group(C). Rats were sacrificed after 9 weeks of treatment. Serum alkaline phosphatase (ALP) and osteocalcin(OC) contents were significantly increased; bone mineral content (BMC) of right femur and the third lumbar body(L3) and the biomechanical properties of right femur were decreased in group B. Treatment with E2 can reverse the changes of BMD and BMC in ovariectomized rats. There was no significant improvement on biomechanical parameters in group C rats. It is concluded that physiological dosage of E2 may inhibit bone resorption and bone formation and increase bone mass, but it may not improve the strength of bone.

Animals↗

PubMed1999

[Investigation of aluminum oxide matrix of the machinable infiltrated ceramic(MIC)].

OBJECTIVE: To explore the effects of different powder/liquid ratio during the procedure of aluminum oxide slip preparation on the properties and microstructure of the machinable infiltrated ceramic(MIC) aluminum matrice. METHODS: PI alpha-Al2O3 powder was employed in this study. Aluminum slip with different powder/liquid ratios of 3.5, 4.5, 5.5, 6.5, 7.5, 8.5, 9.5 and 10.5 was prepared separately. Specimens were slip-casted and pre-fired, and whose physical properties were determined and morphology of specimens was examined under scanning electromicroscope. RESULTS: The packing density increased while the linear shrinkage decreased, when the powder/liquid ratio increased. Elevated pre-firing temperature resulted in higher flexural strength of the matrice. The matrice demonstrated porous morphology under electromicroscope, and neck-fusion between Al2O3 particles was observed and increased with elevated prefiring temperature. CONCLUSION: MIC is a kind of easy-manipulated material with high packing density, optimum porosity and lower linear shrinkage, so it may be an ideal aluminum matrix for infiltrated ceramic.

Aluminum Oxide↗

PubMed1999

[A primary clinical study of HRV analysis of nonlinear dynamics].

We observed the changes of nonlinear dynamic parameters in the patients with diabetes and old myocardial infarction with the methods of nonlinear dynamics. The results indicate that the correlation dimension of the patients with old myocardial infarction is higher than that of the normal, their Lyapunov exponent is lower than the normal's; that the correlation dimension of the patients with diabetes is also higher than that of the normal, their Lyapunov exponent is lower than the normal's; and that the values of the entropy of the two patient groups are basically identical to the entropy of the normal. Therefore the correlation dimension can indicate the changes in the function of autonomic nerve of the patients with diabetes and old myocardial infarction.

Autonomic Nervous System↗