PubMed Health⌕ Search

Biomedical subjects

H Yin

Publications and source records attributed to H Yin.

At least 73 records · Page 4Linked to original sources
PubMed2000

Automated high throughput human CYP isoform activity assay using SPE-LC/MS method: application in CYP inhibition evaluation.

1. A high throughput screening (HTS) method for the evaluation of the seven major human hepatic CYP isoform activities was developed on a 96-well format, with automation. The method utilized pooled human liver microsomes and seven probe substrates, generic conditions for incubation, reaction termination and metabolite extraction with solid phase extraction (SPE) plates. Metabolites from the seven reactions were pooled and quantified using a generic liquid chromatography and tandem mass spectrometry (LCMS/MS) method. 2. The HTS method was validated based on Km values obtained, which were in agreement with literature data. 3. The isoform inhibition profiles of ketoconazole, quinidine, sulfaphenazole, tranylcypromine, alpha-naphthoflavone, and 4-methylpyrazole against CYPs 3A4, 2D6, 2C9, 2A6 land 2C19), 1A2 and 2E1, respectively, were obtained by this HTS method. Graphically obtained IC50 values are in agreement with literature reported values. 4. The HTS method represents a significant efficiency and selectivity improvement over traditional methods, and can be used for CYP inhibition assay and can be extended for liver activity profiling.

Automation↗
PubMed2000

Effective field theory of the zero-temperature triangular-lattice antiferromagnet: A monte carlo study

Using a Monte Carlo coarse-graining technique introduced by Binder [Z. Phys. B 43, 119 (1981)], we have explicitly constructed the continuum field theory for the zero-temperature triangular Ising antiferromagnet. We verify the conjecture that this is a Gaussian theory of the height variable in the interface representation of the spin model. We also measure the height-height correlation function and deduce the stiffness constant. In addition, we investigate the nature of defect-defect interactions at finite temperatures, and find that the two-dimensional Coulomb gas scenario applies at low temperatures.

Journal Article↗
PubMed2000

Induction of apoptosis in BPH stromal cells by adenoviral-mediated overexpression of caspase-7.

PURPOSE: We hypothesized that expression/activity of critical components of the apoptotic pathway can be used to induce apoptosis of a human prostate cell line derived from benign prostatic hyperplasia (BPH) tissue. MATERIALS AND METHODS: We analyzed the apoptotic pathway in BPH cells treated with the powerful inducer of apoptosis, staurosporine (STS), and adenoviruses overexpressing caspase-3, -7, or the control gene lacZ. RESULTS: Twelve hours post-STS, most BPH cells were floating in the culture medium, TUNEL staining was widespread, and DEVDase activity (the catalytic activity of type II caspases) was increased. The pan-caspase inhibitor, Z-VAD-FMK, prevented STS-induced apoptosis. Based on these observations, we performed immunoblot analysis for the three known group II caspases (that is caspase-2, -3 and -7), but none of them was detected with three commercially available antibodies. Nevertheless, in view of the presence of increased DEVDase activity, we reasoned that a group II caspase must be a critical mediator of apoptosis in this model. If correct, we postulated that overexpression and activation of a type II caspase should cause apoptosis. To test this hypothesis, we coupled the cDNAs encoding caspase-3 and caspase-7 to adenoviral vectors and obtained constructs AvC3 and AvC7. Cells infected with AvC3 or AvC7 overexpressed the protein for caspase-3 or -7 within 24 to 48 hours. Caspase-3 overexpression did not cause apoptosis above that observed in cells receiving the control adenovirus expressing the lacZ cDNA (AvLac-Z). In contrast, caspase-7 overexpression induced massive apoptosis. BPH cells were then infected with increasing multiplicity of infection (MOI) of AvC7 and AvlacZ. A positive correlation was found between the amount of caspase-7 expressed and the level of DEVDase activity measured. AvC7 at MOIs of 25:1 and 50:1 induced apoptosis in about 50% of BPH cells at 72 hours post-infection. This effect was AvC7 specific, because the same MOIs of AvlacZ were not apoptogenic. CONCLUSIONS: Adenoviral-mediated overexpression of caspase-7 induces apoptosis of BPH-derived cells.

Adenoviridae↗
PubMed2000

Basal cell carcinoma (BCC) causing spinal cord compression.

Basal cell carcinoma (BCC) is the most common cutaneous malignancy affecting populations with light skin, though these tumors rarely cause severe morbidity or mortality. We report an adult male with back pain and leg weakness associated with a neglected, ulcerated lower back tumor of fifteen years duration. The clinical impression of BCC causing spinal cord compression was confirmed by microscopy and magnetic resonance imaging (MRI).

Basal Cell Carcinoma↗
PubMed2000

Evidence of apoptotic smooth muscle cells in proliferative intima of injured arteries.

OBJECTIVE: To investigate the occurrence and extent of apoptosis in the course of restenosis. METHODS: The experimental models of vessel narrowness and intima thickness were established in minipigs' iliac arteries by balloon injury and specimens were retrieved on the 1st, 3rd, 6th, 12th and 30th days for dynamic observation. Apoptotic smooth muscle cells (SMCs) were detected by terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL). RESULTS: Apoptotic SMCs occurred only in the thickened intima 12 days after injury accompanied with the proliferative SMCs, the percentage of apoptosis was 1.94% +/- 0.42% on the 12th day and 1.36% +/- 0.31% on the 30th day respectively. The low frequency of apoptosis compared with the proliferative SMCs was a feature in the restenotic pathology. CONCLUSIONS: Apoptosis participates in the pathogenetic process of intimal thickening and its level was low compared with proliferation. The findings suggest that attempts to modulate apoptosis after vessel injury constitute a theoretical approach to the prevention of restenosis.

Animals↗
PubMed2000

A large scale epidemiological survey of Graves' disease in Daqing area.

OBJECTIVE: To study the incidence of Graves' disease and the associated factors. METHODS: Totally 100,123 people aged 15 to 79 years in Daqing area were surveyed epidemiologically. The investigation was conducted for two years. RESULTS: All 301 patients with Graves' disease were first diagnosed, with 74 (1.6@1000) males and 227 (4.1@1000) females. The total incidence was 3.0@1000, showing significant differences between ages and between occupations. Investigation of 18 associated factors for Graves' disease by using the logistic multivariate regression analysis showed the pathological factors of the virus infection history, psychological stimulation, food, drugs, family history, education and distribution. CONCLUSION: This study may suggest the theoretical evidence for prevention and treatment of Graves' disease.

Adolescent↗
PubMed2000

[Study on interferon gamma and interleukin-4 contents of plasma and cultured monoclear cell supernatants in patients with endometriosis].

OBJECTIVE: To investigate the cytokin production of T helper cell (Th) 1, Th2 subsets in patients with endometriosis(EM). METHODS: The cytokine production of Th1, Th2 cells expressed by interferon-gamma (IFN-gamma) and interleukin-4 (IL-4) contents respectively in supernatants of cultured PHA induced peripheral blood mononuclear cell (PBMC) and plasma, obtained from 30 EM patients and 15 normal controls were determined by enzyme linked immunoabsorbent assay (ELISA). RESULTS: IL-4 contents of EM patients were elevated both in plasma and PBMC supernatants[(32.0 +/- 22.6) ng/L and (32.8 +/- 12.5) ng/L, respectively], while IFN-gamma levels was suppressed in PBMC supernatant as compared with normal controls [(1,095.6 +/- 375.6) ng/L and (1,549.3 +/- 361.9) ng/L, respectively] (P < 0.01, P < 0.05). As a results, the ratio of IFN-gamma/IL-4 decreased in EM patients. CONCLUSIONS: Changes of IFN-gamma and IL-4 contents in EM patients may reflect functional inbalance between Th1 and Th2 cells, which may play a role in the pathogenesis of EM.

Adult↗
PubMed2000

[T1, T2 squamous or adenocarcinoma of the lung:characteristics of lymph node metastasis and its clinical significance].

OBJECTIVES: To investigate the frequency, distribution and features of lymph node metastasis in T(1)/T(2) squamous or adenocarcinoma of the lung, and to provide evidence for extensive dissection of lymph nodes. METHODS: 254 patients with T(1)/T(2) squamous or adenocarcinoma of the lung underwent R2 surgery plus extensive dissection of hilar, interlobular and mediastinal lymph nodes according to the grouping system proposed by Naruke. RESULTS: 1 685 groups of lymph nodes were dissected. The metastatic rates of N(1) and N(2) was 20.0% and 10.2% respectively. Significant difference existed between T(1) and T(2) tumors (P < 0.01). No N(2) metastasis was found in T(1) squamous cell carcinoma. N(2) metastatic rates were 22.0% in squamous cell carcinoma and 40.9% in adenocarcinoma (P < 0.01). 64.3% of squamous carcinoma spread to only one group of N(2) nodes, and over 3 groups of lymph nodes were positive in 46.2% of adenocarcinoma. Saltatory metastasis accounted for 57.5% of N(2) metastasis. 13.6% of N(2)-positive tumors in upper lobes metastasized to the lower mediastinum, whereas 51.6% of N(2)-positive cancers in the lower lobes spread to the upper mediastinum. CONCLUSIONS: The frequency of lymph nodes metastasis increases with the growth of tumors. Metastasis in adenocarcinoma occurs more frequently than in squamous carcinoma. Tumor at any site can metastasize to the distant mediastinum. Except for T(1) squamous cancer, radical surgery can be achieved only by extensive dissection of ipsilateral intrapulmonary and mediastinal lymph nodes.

Adenocarcinoma↗
PubMed2000

Lymph node metastasis of T1, T2 squamous carcinoma and adenocarcinoma of lung: characteristics and clinical significance.

OBJECTIVES: To investigate the frequency, distribution and features of lymph nodes metastasis in T(1)/T(2) squamous carcinoma and adenocarcinoma of lung, and to provide evidence for extensive dissection of lymph nodes. METHODS: 254 patients with T(1)/T(2) squamous carcinoma and adenocarcinoma of lung underwent R2 surgery plus extensive dissection of hilar, interlobular and mediastinal lymph nodes according to the grouping system proposed by Naruke. RESULTS: A total of 1 685 groups of lymph nodes were dissected. The metastatic rates of N(1) and N(2) were 20.0% and 10.2%. The difference was very significant between T(1) and T(2) (P < 0.01). No, N(2) metastasis was found in T(1) squamous carcinoma. N(2) metastatic rates were 22.0% in squamous carcinoma and 40.9% in adenocarcinoma (P < 0.01). 64.3% of squamous carcinomas spread to only one group of N(2) nodes, and over 3 groups of lymph nodes were positive in 46.2% of adenocarcinomas. Saltatory metastasis accounted for 57.5% of N(2) metastasis. 13.6% of N(2)-positive tumors in the upper lobes metastasized to the lower mediastinum, whereas 51.6% of N(2)-positive tumors in the lower lobes spread to the upper mediastinum. CONCLUSIONS: The frequency of lymph node metastasis increases with the growth of tumors. Metastasis occurs more frequently in adenocarcinoma than in squamous carcinoma. Tumor at any site can metastasize to the distant mediastinum. Except for T(1) squamous carcinoma, radical surgery can be achieved only by extensive dissection of ipsilateral intrapulmonary and mediastinal lymph nodes.

Adenocarcinoma↗
PubMed2000

[Measurement of tumor angiogenesis in primary lung cancer].

OBJECTIVE: To study tumor angiogenesis in primary lung cancer and its relation with lymph node metastasis, tumor cell apoptosis, and cell proliferation. METHODS: Intratumor microvessel was detected by factor VIII polyclonal antibody using immunohistochemistry. Tumor cell apoptosis was detected by TUNEL method. Cell proliferation was analyzed by flow cytometry. RESULTS: Intratumor microvessel density (MD) was significantly lower in stage I lung cancer than in stage II and stage III (P < 0.01). MD was significantly higher in the tumors with lymph node metastasis (P < 0.01). With the increase in MD, there would be a 1.2-fold increase in the risk of lymph node metastasis (P < 0.01). With the increase of MD, apoptosis index (AI) of the tumor significantly decreased, but no relationship between MD and cell proliferation index (PI) was observed. CONCLUSION: Tumor angiogenesis promotes growth and metastasis of lung cancer. Tumor angiogenesis also can inhibit the apoptosis of lung cancer.

Adult↗
PubMed2000

[Pathological study of the pleomorphic carcinoma of the lung].

OBJECTIVE: A clinicopathological study of 10 patients with pleomorphic carcinoma of the lung. METHODS: Histopathological and immunohistochemical staining for keratin, vimentin, Mac387, desmin, actin and S-100 protein were used for this study. RESULTS: Pleomorphic carcinoma of the lung was found to often occur in males above 50 years of age and with clinical symptoms including cough, expectoration, haemoptysis and chest pain. The most frequent microscopic diagnosis was squamous cell carcinoma, and adenocarcinoma, accompanied by spindle and giant cells. The epithelial component of pleomorphic carcinoma of the lung displayed positivity for keratin and the spindle cells displayed positivity for vimentin. In some cases the neoplastic epithelial component and spindle cells showed positive expression of both keratin and vimentin. CONCLUSION: Pleomorphic carcinoma of the lung may display various histopathological changes making it easy to be misdiagnosed as carcinosarcoma. Understanding its pathogenesis and histopathology is important for the diagnosis and differential diagnosis.

Adenocarcinoma↗
PubMed2000

[Textual research on personnels revising Xin xiu ben cao (newly Revised Herbology)].

The problem is investigated by studying annals of Tang - Song period and relevant materials. It is claimed that at the time when Sujing's report was submitted in the second year of Xianqing reign, the officials surveilling and revising the text include in order: ZHANG SUN Wuji, LI Ji, YU Zhining etc, together with SU Jing, the total number being 23. Changes appeared in this number at the time when the work was finished in the fourth year of Xianqing reign. Though, by then, the number involved was still 23, yet the order of LI Ji and ZHANG SUN Wuji was reversed, and Xin Mao jiang took the place of YU Zhining. In addition, the birth time of SU Jing was investigated to be 595 - 600.

China↗
PubMed2000

[Content and activity of the focal adhesion kinase in cultured vascular smooth muscle cells enhanced by urotensin II].

Urotensin II (U II) is the most potent vasoconstrictor identified in vivo, which plays an important role in the smooth muscle cell proliferation in atherosclerosis. All available information suggests that focal adhesion kinase (FAK) is at the crossroads of multiple signaling pathways and is essential for cell proliferation. But the effect of U II on the FAK mediated signal transduction pathway is unclear. In this study, FAK content and tyrosine phosphorylation were assessed by Western blot and immunoprecipitation in cultured rat vascular smooth muscle cells. Increased protein tyrosine phosphorylation was observed within 5 min of U II 10(-7) (mol/L) addition and was maximal by 30 min, while FAK protein content showed no change during the first 30 min but it increased at 2 h reaching a plateau by 4 h, and decreased after 6 h. In addition, the elevated phosphorylation of FAK was detected upon U II stimulation at 10(-8) mol/L, being maximal at 10(-7) mol/L, but decreased at 10(-6) mol/L. Treatment of the cells with cytochalasin B (50 micromol/L), which disrupted the organization of cytoskeleton, had no influence on the increased FAK tyrosine phosphorylation in response to U sti II mulation. In order to study the relationship between FAK and mitogen-activated protein kinase, calmodulin and protein kinase C, selective inhibitors PD98059 (50 micromol/L), W7 (50 micromol/L) and H7 (50 micromol/L) were added following U II treatment. Neither PD98059 nor W7 influenced the increased FAK tyrosine phosphorylation, but H7 further increased it. These findings indicate that FAK activation is independent of the integrity of cytoskeleton and closely related to protein kinase C, but had no relation with mitogen activated protein kinase and calmodulin.

Animals↗
PubMed2000

[Effects of nitrogen feeding on the accumulation of poly-beta-hydroxybutyrate with Alcaligenes eutrophus].

On the basis of analysis of PHB fermentation processes, the effects of ammonium sulfate feeding rate at PHB formation period on the PHB accumulation by Alcaligenes eutrophus were investigated. It was shown that the complete absence of nitrogen source at PHB formation phase would lead to the decline of PHB synthetic activity, and the obvious influences of different nitrogen feeding rate on PHB synthesis were observed. Higher PHB content, but relative lower cell dry weight, PHB concentration and PHB productivity could be obtained at slower nitrogen feeding rate. The excessive nitrogen feeding rate resulted in the drop of PHB content, which led to the decrease of PHB concentration and PHB productivity. The better results could be achieved when the ammonium sulfate feeding rate was set at around 0.5 g/h.

Ammonium Sulfate↗
PubMed1999

Nonequilibrium mechanism of transcription termination from observations of single RNA polymerase molecules.

Cessation of transcription at specific terminator DNA sequences is used by viruses, bacteria, and eukaryotes to regulate the expression of downstream genes, but the mechanisms of transcription termination are poorly characterized. To elucidate the kinetic mechanism of termination at the intrinsic terminators of enteric bacteria, we observed, by using single-molecule light microscopy techniques, the behavior of surface-immobilized Escherichia coli RNA polymerase (RNAP) molecules in vitro. An RNAP molecule remains at a canonical intrinsic terminator for approximately 64 s before releasing DNA, implying the formation of an elongation-incompetent (paused) intermediate by transcription complexes that terminate but not by those that read through the terminator. Analysis of pause lifetimes establishes a complete minimal mechanism of termination in which paused intermediate formation is both necessary and sufficient to induce release of RNAP at the terminator. The data suggest that intrinsic terminators function by a nonequilibrium process in which terminator effectiveness is determined by the relative rates of nucleotide addition and paused state entry by the transcription complex.

Base Sequence↗
PubMed1999

Characterization of human MMTV-like (HML) elements similar to a sequence that was highly expressed in a human breast cancer: further definition of the HML-6 group.

Previously, we found a retroviral sequence, HML-6.2BC1, to be expressed at high levels in a multifocal ductal breast cancer from a 41-year-old woman who also developed ovarian carcinoma. The sequence of a human genomic clone (HML-6.28) selected by high-stringency hybridization with HML-6.2BC1 is reported here. It was 99% identical to HML-6.2BC1 and gave the same restriction fragments as total DNA. HML-6.28 is a 4.7-kb provirus with a 5'LTR, truncated in RT. Data from two similar genomic clones and sequences found in GenBank are also reported. Overlaps between them gave a rather complete picture of the HML-6.2BC1-like human endogenous retroviral elements. Work with somatic cell hybrids and FISH localized HML-6.28 to chromosome 6, band p21, close to the MHC region. The causal role of HML-6.28 in breast cancer remains unclear. Nevertheless, the ca. 20 Myr old HML-6 sequences enabled the definition of common and unique features of type A, B, and D (ABD) retroviruses. In Gag, HML-6 has no intervening sequences between matrix and capsid proteins, unlike extant exogenous ABD viruses, possibly an ancestral feature. Alignment of the dUTPase showed it to be present in all ABD viruses, but gave a phylogenetic tree different from trees made from other ABD genes, indicating a distinct phylogeny of dUTPase. A conserved 24-mer sequence in the amino terminus of some ABD envelope genes suggested a conserved function.

Adult↗
PubMed1999

Effect of electric field on liquid chromatographic separation of peptide digests. Combining capillary separation techniques.

A system is described which allows operation of a range of capillary based liquid phase separations including capillary electrophoresis, isocratic and gradient capillary electrochromatography, isocratic and gradient capillary liquid chromatography and electrically assisted gradient capillary liquid chromatography. The system was coupled to electrospray ionization mass spectrometry in the electrically assisted capillary liquid chromatography mode to investigate the effect of applied voltage on the selectivity in peptide mapping separations. Analyses were performed on tryptic digests of recombinant human growth hormone and tissue plasminogen activator. The results show a small but useful effect on selectivity that can be used to fine tune specific separations.

Algorithms↗