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Biomedical subjects

L Sui

Publications and source records attributed to L Sui.

27 records · Page 2Linked to original sources
PubMed1999

The concurrent expression of p27(kip1) and cyclin D1 in epithelial ovarian tumors.

Mammalian cell-cycle progression is regulated by the combined action of cyclins/cyclin-dependent kinases (cdks) and cdk inhibitors. Abnormal expression as well as interaction of these proteins may result in malignant transformation of cells. To further address alterations and roles of these cell-cycle proteins in the development of epithelial ovarian carcinomas, we analyzed the expression of the p27(kip1), cyclin D1, cyclin E, and cdk2. A panel of 79 epithelial ovarian tumors was selected. Immunohistochemical staining of serial paraffin sections was performed using antibodies to p27(kip1), cyclin D1, cyclin E, and cdk2. The results showed that p27(kip1) and cyclin D1 were concurrently expressed in epithelial ovarian tumors, and the expression was down-regulated in ovarian carcinomas. There was an inverse relationship between the expression level of p27(kip1) and cyclin D1 and the histological tumor grades. On the other hand, the expression of cyclin E and cdk2 was enhanced in ovarian carcinomas. The results suggest that low expression of p27(kip1) and cyclin D1 as well as high expression of cyclin E and cdk2 promotes the development of ovarian tumors. p27(kip1) and cyclin D1 expression are negatively correlated with the malignant degree of epithelial ovarian tumors. Thus, the ovarian tumors with high p27(kip1) and cyclin D1 expression may generally have a somewhat better prognosis, while those with low p27(kip1) and cyclin D1 expression may have a worse prognosis.

CDC2-CDC28 Kinases↗
PubMed1998

[Establishment and discretization of human torso computer images for ECG simulation].

The establishment and discretization of human torso computer image is an important aspect in studying of ECG simulation. A rapid and effective method is presented in this paper, which establishes and discretes image of human torso exactly by curve fitting and by introducing concept of "nihility point". It also has some value for solving problem of discreting field region in numerical calculation of electromagnetic field.

Algorithms↗
PubMed1997

Secondary structure and shape of plasma sex steroid-binding protein--comparison with domain G of laminin results in a structural model of plasma sex steroid-binding protein.

We have analyzed the secondary structure, shape and dimensions of plasma sex steroid-binding protein (SBP) by CD, size-exclusion chromatography and electron microscopy. CD spectra show extrema at 186 nm and 216 nm characteristic for beta-sheet structures. Analysis with different algorithms indicates 15% alpha-helix, 43% beta-sheet and 10-16% beta-turn structures. An irreversible structural change is observed upon heating above 60 degrees C, which correlates with the loss of steroid-binding activity. As the SBP sequence shows similarity with domains of several multidomain proteins, including laminins, we evaluated the structure of domain G of laminin-1. The CD spectrum shows extrema at 200 nm and 216 nm. Deconvolution results in 13% alpha-helix, 32% beta-sheet and 15% beta-turn structures. Steroid-binding assays indicate that laminin and fragments thereof have no activity. Size-exclusion chromatography reveals that SBP has an extended shape and can be modeled as a cylinder with a length and diameter of 23 nm and 3 nm, respectively. This shape and the dimensions are in agreement with the appearance on electron micrographs. We propose a model for the structure of SBP in which two monomers assemble head to head with the steroid-binding site located in the center of the rod-like particle.

Amino Acid Sequence↗
PubMedDate not supplied

Age-related impairment of long-term depression in area CA1 and dentate gyrus of rat hippocampus following developmental lead exposure in vitro.

Chronic developmental lead exposure is known to be associated with cognitive dysfunction in children. Impairment of the induction of long-term depression (LTD) has been reported in area CA1 and dentate gyrus (DG) of rat hippocampus following chronic lead exposure. The present study was carried out to investigate age-related alterations of LTD in area CA1 and DG of rat hippocampus following developmental lead exposure in vitro. Neonatal Wistar rats were exposed to lead from parturition to weaning via milk of dams drinking 0.2% lead acetate solution. Field excitatory postsynaptic potentials (EPSPs) were recorded in hippocampal slices at various postnatal ages: postnatal day (PND) 17-23, 27-33, and 57-63. Following low-frequency stimulation (LFS, 900 pulses/1 Hz), the average magnitude of LTD is age related. In the controls, LTD magnitude in area CA1 decreased with age, whereas in DG it increased with age. In the lead-exposed groups, the magnitude of LTD declined during development in both area CA1 and DG. The differences of LTD magnitude between the control and lead-exposed rats were 27.26 +/- 9.15% (PND 17-23), 21.59 +/- 12.93% (PND 27-33), and 16.96 +/- 9.33% (PND 57-63) in area CA1, and were 6.95 +/- 9.26%, 17.60 +/- 3.91%, and 33.63 +/- 10.47% in DG, respectively. These results demonstrated that the lead-induced impairment of LTD magnitude was an age-related decline in area CA1 and an age-related increase in area DG of rat hippocampus. Published by Elsevier Science Inc.

Aging↗
PubMedDate not supplied

Two components of long-term depression are impaired by chronic lead exposure in area CA1 and dentate gyrus of rat hippocampus in vitro.

Previous studies have demonstrated that low-level lead exposure can impair the induction of long-term depression (LTD) in area CA1 and dentate gyrus (DG) of rat hippocampus in vitro and in vivo. The induction of LTD in area CA1 and DG has been shown to associate with N-methyl-D-aspartate receptors (NMDARs) and voltage-gated calcium channel (VGCC). In this study, the relative contributions of NMDARs-dependent and VGCC-dependent components in the induction of LTD in the hippocampus and the impairments of these two components of LTD by chronic low-level lead exposure were investigated. Neonatal Wistar rats were exposed to lead from parturition to weaning via milk of dams drinking 0.2% lead acetate solution. Field excitatory postsynaptic potentials (EPSPs) were recorded in area CA1 and DG before and after two 15-min trains of 1-Hz low-frequency stimulation (LFS) (2x900 pulses). In area CA1, the amplitude of NMDARs-dependent LTD (NMDA-LTD), in the presence of 10 microM nimodipine (a blocker of L-type Ca(2+) channels), was 80.05+/-2.54% (n=8) and 94.58+/-10.57% (n=8) in the control and lead-exposed rats, respectively. The amplitude of VGCC-dependent LTD (VGCC-LTD), in the presence of 50 microM (-)-2-amino-5-phosphonopentanoic acid (AP5), was 80.36+/-4.08% (n=10) and 93.91+/-7.85% (n=10) in the control and lead-exposed rats, respectively. In area DG the amplitude of NMDA-LTD, with both 50 microM Ni(2+) (a blocker of T-type Ca(2+) channels) and 10 microM nimodipine present, in the control rats (79. 97+/-4.30%, n=8) was significantly larger than that in the lead-exposed rats (91.24+/-11.08%, n=10, P<0.001). The amplitude of VGCC-LTD, with 50 microM AP5 present, was significantly larger in the control rats (70.80+/-3.64%, n=9) than that in the lead-exposed rats (87.60+/-9.00%, n=10, P<0.001). The results suggested that chronic lead exposure affected two components of LTD induction in area CA1 and DG. Furthermore, the impairment of two components by lead exposure might be similar in area CA1, while the impairment of VGCC-LTD might be more serious in DG of hippocampus.

2-Amino-5-phosphonovalerate↗
PubMedDate not supplied

Management of abnormal uterine hemorrhage with atypical endometrial hyperplasia by transcervical resection of endometrium.

The aim of the study was to assess the feasibility and effect of treating atypical endometrial hyperplasia (AEH) with transcervical resection of endometrium (TCRE). Five cases of AEH incapable of hysterectomy for various reasons were treated with TCRE. All patients were followed up for 3-4 years postoperation to evaluate the thickness of endometrium, uterine cavity, and prognosis of the disease. All the patients provided informed consent for TCRE. In all five cases treated with TCRE, case 1 was for senility, hypertension, diabetes mellitus, and obesity; case 4 for senility, obsolete cerebral infarction, and hemiplegia; case 5 for uremia and chronic dysfunction of coagulation after renal transplantation; cases 2 and 3 for rejection of hysterectomy. All cases were followed up for more than 3 years after operation. Four had amenorrhea and one had dropping menses. The thickness of endometrium was no more than 5 mm in all the cases. TCRE is one available microinvasive surgery alternative to hysterectomy for AEH patients contraindicated to hysterectomy.

Aged↗
PubMedDate not supplied

The overexpression of cyclin-dependent kinase (CDK) 2 in laryngeal squamous cell carcinomas.

We examined the expression of CDK2 using immunohistochemistry in 102 cases of laryngeal squamous cell carcinomas (LSCCs). The results showed that a total of 63.73% (65/102) patients revealed a CDK2 overexpression pattern and the CDK2 overexpression was correlated significantly with the tumor site, tumor size and advanced stage. A positive correlation between the CDK2 expression and proliferative activity of tumor cells measured by proliferating cell nuclear antigen was found (r = 0.894, p < 0.0001). The Kaplan-Meier's analysis showed that shorter disease-free survival was significantly associated with tumor grade, tumor size, lymph node metastasis and advanced stage. Overall survival was significantly associated with tumor grade, tumor size, lymph node metastasis, advanced stage and CDK2 overexpression. When CDK2 and PCNA were combined, the patients with both CDK2 overexpression and PCNA overexpression had a poorer overall survival. We concluded that the CDK2 overexpression may be associated with the malignant biological behavior of LSCCs.

Biomarkers, Tumor↗