Biomedical subjects

P Y Li

Publications and source records attributed to P Y Li.

At least 19 recordsLinked to original sources

PubMed2001

[Effect and mechanism study of kidney tonifying and blood circulation activating Chinese drugs on development of mammary glands in female juvenile rats].

OBJECTIVE: To study the effect and mechanism of Kidney tonifying and blood circulation activating Chinese drugs (KB) on development of mammary gland. METHODS: Using the female juvenile rats as the experimental targets, the level of serum hormone, the amount and affinity of estradiol receptor (ER) and progesterone receptor (PR) as well as the DNA content and relative weight of the rats' mammary glands were measured to study the effect of KB at the pre-receptor, receptor and post-receptor level. RESULTS: KB markedly enhanced the serum level of estradiol, progesterone and the growth hormone (GH) at pre-receptor level, increased the number and affinity of estradiol and progesterone receptors both in the cytoplasm and nucleus at the receptor level. While at the level of post-receptor, it increased the DNA content and the weight index of mammary glands. CONCLUSION: The Kidney tonifying and blood circulation activating Chinese drugs are effective in promoting the growth and development of mammary glands.

Animals↗

PubMed2001

[Effects of kidney reinforcing and blood circulation activating Chinese medicine on morphological structure of mammary glands in models of mammary atrophy and hyperplasia in female rats].

OBJECTIVE: To study the effects and mechanism of Kidney reinforcing and blood circulation activating Chinese medicine (K&B) on morphologic structure of mammary glands in female rat models of mammary atrophy and mammary hyperplasia. METHODS: The models of mammary gland atrophy and hyperplasia were established respectively by ovariectomy and diethylstilbestrol injection to observe the changes of gland's weight index, structure, estradiol receptor (ER) and progesterone receptor (PR) after treated by K&B. RESULTS: (1) K&B could ameliorate the atrophied structure of mammary gland with significant increase of weight index (P < 0.01), raise the number of ER and PR in mammary tissue and nuclei (P < 0.01, P < 0.05), normalize the ratios of ER and PR in plasma and those in nucleus (EnR/EcR and PnR/PcR). (2) K&B could also improve or restore the proliferated structure of mammary gland and its weight index as well as the EnR/EcR and PnR/PcR ratios. CONCLUSION: K&B has the effects in preventing and improving the mammary gland atrophy induced by hyposecretion of sexual hormone and promoting the development of mammary gland in adult rats. Although both K&B and estrogen can improve the development of mammary gland, their mechanisms are different. There is a bright future of K&B in treating underdevelopment of mammary gland.

Animals↗

PubMed2000

Binding of [99mTc]TRODAT-1 to dopamine transporters in patients with Parkinson's disease and in healthy volunteers.

UNLABELLED: [99mTc]TRODAT-1 is a radiolabeled tropane that binds dopamine transporters. The primary goal of this study was to determine whether its regional cerebral distribution could differentiate between patients with Parkinson's disease and healthy human volunteers. METHODS: The sample consisted of 42 patients with Parkinson's disease, 23 age-matched controls, and 38 healthy adults younger than 40 y old. SPECT scans of the brain were acquired on a triple-head gamma camera 3-4 h after the intravenous injection of 740 MBq (20 mCi) [99mTc]TRODAT-1. Mean counts per pixel were measured manually in subregions of the basal ganglia and normalized to the mean background counts to give specific uptake values ([SUVs] approximately k3/k4). Patient and control groups were also compared with automated statistical parametric mapping techniques. Logistic discriminant analyses were performed to determine the optimum uptake values for differentiating patients from age-matched controls. RESULTS: Quantitative image analysis showed that the group mean SUVs in patients were less than the mean values in controls for all regions (all Ps < 0.000001). There was overlap in the caudate as well as in the anterior-most portion of the putamen, but not in the posterior putamen, even when the asymptomatic sides of 5 patients with clinically defined hemi-Parkinson's disease were factored in. CONCLUSION: The findings indicate that Parkinson's disease can be detected with [99mTc]TRODAT by simply inspecting the images for uptake in the posterior putamen. Appropriate asymmetries seem to be visible with quantification in patients with clinically defined hemi-Parkinson's disease, even though changes in the putamen contralateral to the clinically unaffected side in these patients appear to precede the development of symptoms.

Adult↗

PubMed1996

Local concentration of folate binding protein GP38 in sections of human ovarian carcinoma by in vitro quantitative autoradiography.

UNLABELLED: Folate binding protein (FBP) GP38 is a membrane-associated glycoprotein that mediates the intracellular transport of folates. The enhanced expression of FBP in ovarian carcinomas provided a rational basis for clinical studies with specific monoclonal antibodies and some newly synthesized antifolate drugs. Because the outcome of these clinical studies ultimately depends on the degree of FBP expression, we measured the local concentration of FBP using 125I-MOv18 monoclonal antibody and quantitative autoradiography. METHODS: Tissue sections from 37 specimens of ovarian carcinoma and 13 nonmalignant ovaries were incubated with increasing concentrations of 125I-MOv18 with and without an excess of unlabeled antibody. Tissue-bound radioactivity was measured by quantitative autoradiography. RESULTS: Folate binding protein was found to be overexpressed in 91% of nonmucinous ovarian carcinomas, with local concentrations ranging between 1.14 and 82.84 pmole/g. Adjacent tumor sections simultaneously studied with 125I-MOv18 and a 125I-labeled folic acid derivative showed matching and superimposable regional distributions of bound radioactivity of the two radioligands, indicating that the antigen, specifically recognized by 125I-MOv18 in nonmucinous ovarian carcinomas, is capable of binding folates. Nonmalignant ovaries did not contain measurable amounts of antigen when assayed with 125MOv18 but showed a limited and specific binding of the 125I-folic acid derivative to tissue sections. The autoradiographic findings were confirmed by testing sections from mixtures of antigen-positive and antigen-negative cells, by immunoperoxidase staining with MOv18 on tumor sections and by biochemical identification of FBP in membrane fractions from tissue samples. CONCLUSION: Folate binding protein is overexpressed up to 80-90-fold in nonmucinous ovarian carcinomas compared with nonmalignant ovaries. Quantitation of FBP may provide a useful tool in the design of clinical studies with specific monoclonal antibodies and certain antifolate drugs that enter the cell through FBP.

Adenocarcinoma, Mucinous↗

PubMed1995

[Establishment of adriamycin-resistant human ovarian carcinoma cell line and its mechanism of multidrug resistance].

A multidrug-resistant cell line (A2780/ADM) of human ovarian carcinoma which can resist 0.8 microgram.ml-1 of adriamycin (ADM) was obtained by step-wise selection exposure to increasing doses of ADM. A2780/ADM cells showed 17-fold higher resistance to ADM than A2780 cells. The doubling times were 43.8 h in A2780/ADM and 26.3 h in A2780 cells. Colony formation rates were 15%-20% in A2780/ADM and 65%-75% in A2780 cells. A2780/ADM cell line was also shown to significantly cross-resistant to vincristine (VCR) and VP-16, but no cross-resistance was found to 5-Fu, PDD or Mel. A further investigation showed that intracellular accumulation of ADM in A2780/ADM was significantly decreased. Expressions of P-glycoprotein and GST-pi were increased in A2780/ADM by means of immunohistochemical method. Verapamil (Ver) combined with ADM was found to increase the sensitivity and reverse the resistance to ADM in A2780/ADM. This study indicates that A2780 ADM has the peculiarity of multidrug resistance and there may be other mechanism of drug-resistance besides MDR related to P-170.

Doxorubicin↗

PubMed1994

In vitro receptor imaging for characterization of human solid tumors.

Since many of the factors involved in tumor growth and progression act through a receptor-mediated mechanism, we applied in vitro receptor imaging techniques to study the intratumoral distribution and concentration of receptor-molecules having experimental biological relevance in such processes. Here we summarize the results of a study concerning the role of urokinase receptor (uPAR) in the acquisition of an invasive phenotype by tumor cells. Independently of the system studied, we demonstrated that in vitro receptor imaging techniques can be used to define the biological characteristics of human solid tumors and can contribute to clarify the complex network of ligand/receptor interactions leading to tumor spread.

Autoradiography↗

PubMed1994

Enhanced immunogenicity in mice with hepatitis B vaccine complexed to human hepatitis B immunoglobulin.

Purified human hepatitis B immunoglobulin (HBIG) was complexed to plasma derived hepatitis B vaccine (HBVac) at different concentrations and used to immunize Balb/c mice. An enhanced humoral immune response was observed when HBVac was complexed to HBIG in excess of antigen, compared to that immunized with the vaccine alone. Proliferation of splenic lymphocytes was detected when mice were immunized with HBIG complexed to HBVac (0.2-1 microgram), whereas in mice immunized only with HBVac at one microgram, no lymphocyte proliferation was observed. The enhanced immunogenicity of HBIG: HBVac is T cell dependent. The importance of using critical ratio of HBIG and HBVac is indicated, and future application of this complex for vaccination of low- or nonresponders to the present HBVac, as well as for treatment of chronic hepatitis B patients is discussed.

Animals↗

PubMed1993

Human urokinase receptor concentration in malignant and benign breast tumors by in vitro quantitative autoradiography: comparison with urokinase levels.

We measured the tissue concentration of human urokinase receptor (uPAR) in 22 breast carcinomas and 9 benign breast lesions using in vitro quantitative autoradiography. Tissue sections were incubated with increasing concentrations of 125I-pro-urokinase in the presence or absence of unlabeled competitor. Breast carcinomas were found to contain 5 times more uPAR than benign breast lesions with respect to their protein content [523 +/- 72 versus 108 +/- 20 (SE) fmol/mg (P < 0.001)]. Simultaneous quantitation of urokinase (uPA) by immunoenzymatic assay on tissue extracts from the same specimens showed that breast carcinomas also contain 19 times more uPA than benign tumors (611 +/- 134 versus 32 +/- 8 fmol/mg) (P < 0.01). The reliability of quantitative autoradiography measurements was confirmed by uPAR cross-linking assay on membrane fraction from either U937 histiocytic lymphoma cells or breast carcinomas and immunoperoxidase staining with an anti-uPAR antibody on tumor sections. Also, immunoperoxidase staining with an anti-uPA monoclonal antibody showed that uPA is indeed localized on the plasma membrane of epithelial tumor cells in confined areas of breast carcinomas whereas cells from benign breast lesions were devoid of uPA under the same experimental conditions. In conclusion, our findings support the hypothesis that uPAR plays a central role in the acquisition of an invasive phenotye and favor its potential use as a prognostic factor in patients with breast carcinoma.

Adult↗

PubMed1993

Serum cholesterol determined by liquid chromatography with 6-chlorostigmasterol as internal standard.

We describe an accurate and precise method for determining serum cholesterol by high-performance liquid chromatography (HPLC). After addition of 6-chlorostigmasterol as internal standard, serum is treated with alcoholic potassium hydroxide. Subsequently the cholesterol and internal standard are extracted from the mixture into n-hexane and then derivatized to phenylurethanes for measurement by HPLC with ultraviolet detection. The effective chromatographic separation and the use of an appropriate internal standard make this procedure free from interferences by other serum sterols and precise. The mean cholesterol concentration in Standard Reference Material (SRM) 909 (human serum) assayed by this procedure (4.346 mmol.g-1 x L-1) agreed well with the value assigned by the National Institute of Standards and Technology (4.359 mmol.g-1 x L-1). Within-run and total CVs were 0.56% and 0.78%, respectively. Therefore the performance of this procedure is sufficiently good to allow its use as a candidate reference method for serum cholesterol determination.

Cholesterol↗

PubMed1992

Feedforward stabilization in a bimanual unloading task.

When one hand removes a load from the other hand, feedforward motor commands stabilize the position of the unloaded hand. We studied the stabilization of the postural hand using a novel apparatus that allowed unloading at different rates, and unexpected uncoupling of the unloading force from the postural hand. Feedforward stabilization of hand position was observed in all subjects. This stabilization was achieved both by deactivation of postural agonist muscles and by activation of postural antagonist muscles. The neural feedforward command apparently increased with unloading rate. However, the command only partially canceled the interaction torque generated by removing the load, and stabilization became less effective as unloading rate increased.

Electromyography↗

PubMed1992

Elimination of immune tolerance to hepatitis virus in an animal model.

Four-day old ducklings were infected with duck hepatitis B virus to simulate perinatal transmission of hepatitis B virus. Immune tolerance was characterized as persistent viremia, antigenemia, without detection of anti-DHBs or anti-DHBc. A synthetic peptide, P125-146, mimicking one of the epitopes of the native DHBV Pre-S protein was used to cross-link to tetanus toxoid or phytohemagglutinin. These 'novel' antigens were used to immunize immune tolerant ducks, aimed at bypassing T cell tolerance. After 5 injections, though no anti-DHBV Pre-S was detected, around 50% of the immunized ducks showed seroconversion to DHBV DNA negative.

Amino Acid Sequence↗

PubMed1989

[Eye symptoms due to ginseng poisoning].

Ginseng has been used as a tonic for mind and body. A large number of pharmacological studies on ginseng have been done and the variety of effects were shown. In this paper 2 cases of ginseng poisoning has been reported the effects on both eyes were mydriasis and disturbance in accommodation, and the systemic symptoms included dizziness and semiconsciousness, which may be associated with hyperexitability of the sympathetic nerves (adrenergic nerves) due to overdose ginseng.

Accommodation, Ocular↗

PubMed1988