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Biomedical subjects

Y Shan

Publications and source records attributed to Y Shan.

47 records · Page 3Linked to original sources
PubMed1994

[Assay of DNA content and estrogen receptor status in human breast cancer].

Cellular DNA content of 72 samples was analyzed by flow cytometry. The results showed that 20 benign tumors and 10 normal breast tissue specimens were found to be DNA diploidy. 26 (62%) of 42 cases of breast cancer were DNA aneuploidy and the remainders were DNA diploidy. The median s-phase cell percentage was significantly higher in aneuploid tumors (28%) than diploid tumors (13%) and benign tumors (4%). Estrogen receptors were also investigated in 42 breast cancer specimens. There were 31 ER positive (74%) cases and 11 negative (26%) cases. The aneuploid DNA content was usually associated with lack of estrogen receptors. DNA content correlated significantly with age and ER status. The results suggest that flow cytometric analysis of cellular DNA content of breast cancer and status of estrogen receptors can provide an objective quantitative and reproducible new parameter for predicting prognosis of breast cancer.

Adult↗
PubMed1993

Characterization of immobilized Escherichia coli alkaline phosphatase reactors in flow injection analysis.

The characterization of immobilized Escherichia coli alkaline phosphatase reactors used in flow injection analysis is reported for factors such as optimum pH, activity, ionic strength, product inhibition, and substrate specificity. The kinetics of the immobilized enzyme was studied, and mathematical descriptions were developed for the use of an immobilized enzyme packed-bed reactor to evaluate the kinetic parameters and the number of active sites on the immobilized enzyme. Suppression of phosphatase activity by orthophosphate was found to be significantly reduced, and the Michaelis-Menten constant increased when the enzyme was immobilized and packed in a reactor. Immobilized E. coli alkaline phosphatase exhibited similar activity at pH 8 in Tris-HCl, NaHCO3 and borate-HCl buffers but slightly lower activity in NH3H2O-NH4Ac buffer. The performance of the immobilized enzyme reactor was not affected by the presence of up to 10 M Mg(II), Ni(II), Cd(II), Co(II), Mn(II), Cu(II), or urea, 1 M Fe(II), or 0.1 M Fe(III) in the substrate stream. The chelating agent EDTA, however, gradually deactivated the immobilized enzyme. The periodic restoration of enzyme activity was achieved following the removal and addition of zinc ions. The immobilized E. coli alkaline phosphatase packed-bed reactor was used to measure the alkaline phosphatase available phosphorus content of a number of model organophosphorus compounds. p-Nitrophenyl phosphate showed a linear response in the range of 1.6 x 10(-7)-1.6 x 10(-4) M. This study forms part of a larger program to develop enzymatic systems for water quality measurement.

Alkaline Phosphatase↗
PubMed1992

[Effect of flavone glycosides of Epimedium koreanum on murine fibrinolytic system and apoplectic mortality].

The enhancement of fibrinolytic ability of stimulated murine macrophages by flavone glycosides of Epimedium koreanum (TFG) was measured by the [125I]-fibrin-coated plate method. The activity of the plasminogen activator (PA) induced by TFG was determined by a spectrophotometric assay. The activity of PA produced by TFG-stimulated macrophages was 0.731 IU/ML. (P < 0.01). TFG-stimulated macrophages showed rapid fibrinolysis. The activity of stimulated macrophages was approximately 2.8 fold that of the control. In in vivo experiments, the effect of TFG on spontaneously hypertensive and apoplexy rats (SHRsp) was very evident. The abiotic rate of TFG-stimulated rats was 5%, while that of the control group was 90%. TFG showed obvious hypotensive activity as well.

Animals↗
PubMed1991

[Laminin distribution in the clonal cells of PLA-801 (pulmonary giant cell carcinoma) cell line and its effect on tumor cell migration].

LN distribution in clone C and clone D cells of the PLA-801 (pulmonary giant cell carcinoma) cell line was studied with immunocytochemical staining. There were less LN and LN receptors found in clone C cells, which were from a low metastatic cell line, but much more LN and LNR were obtained in the highly metastatic clone D cells. The in vitro migration rates of these 2 clones were measured with agarose migratory analysis. The rate of clone D was much greater than that of clone C. With the presence of exgenous LN, clone C cells became activated with a higher migration rate and the migration rate of clone D was greatly reduced when cells were pretreated with anti-LN antibody. These results indicated that LN and LNR may play a vital role in the migration and metastasis of tumor cells.

Animals↗
PubMed1989

[The clinical application of visual electro-oculography].

A detailed visual electro-oculographic study is performed in patients with hereditary juvenile retinoschisis, Stargardt's disease, senile macular degeneration, surgically reattached retinal detachment, and primary retinitis pigmentosa. The study defined the extent of functional damage of the RPE-photoreceptor complex, elucidated the visual electro-oculographic characteristics, and explored the practical value of visual electro-oculogram in the diagnosis and research of the mentioned diseases. The study also confirmed that the criteria the authors proposed for the assessment of visual electro-oculogram with Arden's ratio and the light peak potential was superior to the use of Arden's ratio alone, as it analyzed the visual electro-oculogram in an all-round way and markedly raised the rate of clinical diagnosis.

Adolescent↗
PubMedDate not supplied

Abnormal function of the parvocellular visual system in anisometropic amblyopia.

PURPOSE: To study the function of the parvocellular (P) and the magnocellular (M) visual systems with steady-state visual evoked potentials (VEPs) in anisometropic amblyopes. METHODS: A matrix of isolated checks was superimposed on a steady background with different check sizes and temporal frequencies to form specific stimuli to preferentially activate the P or the M visual system. The amplitude of the VEP fundamental frequency was analyzed at the electrode Oz of 5 anisometropic amblyopes and 22 normal subjects. The normal subjects were tested at two visual acuity (VA) levels, 20/20 and 20/40, modified by lenses, to match with the VA levels of the fellow eyes and the amblyopic eyes of the amblyopes, respectively. RESULTS: No significant amplitude difference was found between the dominant eyes and nondominant eyes of the normal subjects for either P or M stimuli at both 20/20 and 20/40 VA levels (P>.05). No significant amplitude difference was found between the fellow eyes of the amblyopes and the dominant eyes of normals for either P or M stimuli at 20/20 VA level (P>.05). A significant amplitude difference was found between the amblyopic eyes and the nondominant eyes of the normals for P stimuli (P<.05) but not for M stimuli (P>.05) at 20/40 VA level. CONCLUSIONS: The amplitude of the VEP fundamental frequency was selectively reduced for P stimuli in anisometropic amblyopic eyes. This clinical electrophysiologic finding confirms that only the function of the P visual system is abnormal in anisometropic amblyopic eyes.

Adolescent↗