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Biomedical subjects

L Li

Publications and source records attributed to L Li.

At least 1,297 records · Page 72Linked to original sources
PubMed1997

[Alternative splicing of the FMR1 gene in human fetal tissues].

OBJECTIVE: To gain more insight into biological role of the alternative splicing of the FMR1 gene, isoforms of the FMR1 mRNA from human fetal heart, spleen, liver and kidney were analyzed. METHODS: RNAs were isolated from the tissues of an abortion fetus (approximately 6 months postconception). Alternative splicing patterns of the FMR1 mRNA were analyzed by RT-PCR and cloning strategy. RESULTS: One isoform of the FMR1 mRNA was found to be dominant in all of the four tissues. The major isoform was as same as the dominant one in the fetal cortex but was different from the major isoform in adult brain. The difference between the major isoforms in the fetal tissues and adult brain was the splicing out or retaining the peptide encoded by exon 12 and exon 17. CONCLUSION: This result suggested a developmental switch of alternative splicing of the FMR1 gene. The difference between the major isoforms in the fetal tissues and adult brain suggested the two peptides may have special roles in related developmental stages.

Alternative Splicing↗
PubMed1997

[A quantitative study of microvascular density and proliferating cell ratio in buccal mucosa squamous cell carcinoma].

By the ABC enzyme labelling method we studied the microvascular density and proliferating cell ratio in buccal mucosa squamous cell carcinoma (BMSCC) and in normal buccal tissues quantitatively. These two parameters in BMSCC are 208% and 335% (P < 0.05) respectively which are distinctly higher than those of the normal buccal tissues, indicating malignant features of the carcinoma. The distribution of proliferating cells, corresponds to the area where the microvascular density is high, mainly in the periphery and basal parts of cancer nests. There is a dependent relationship between them, showing a linear positive correlation statistically. The results confirm that angiogenesis and cancer cell proliferation promote each other. They are two important indexes of the local biological behavior of BMSCC and are very important to predict the malignant potential and to evaluate therapeutic effect for BMSCC.

Adult↗
PubMed1997

[Bone histomorphometric changes in ovariectomized goat at different time courses].

Using histopatholoical method, we investigated the bone histomorphometric changes in ovariectomied goats at different time courses. Eight goats, female, aged one and a half years, were randomly divided into two groups, the control and the ovariectomy (OVX). Iliac crest biopsies were separately processed before ovariectomy and at 60 days, 120 days and 180 days after ovariectomy. The histomorphometric changes were observed. It was found that the bone structure in trabecular bone remained relatively constant in the control group throughout the whole study. In contrast, the trabecular quantity was slightly decreased and the trabeculae were disconnected in OVX at 60 days after ovariectomy. The bone structure was characterized by the thinning of the trabeculae, the further discontinuance and quantity loss of trabeculae, and the anlargement of marrow cavity at 120 days to 180 days after ovariectomy. Apparently, these bone structural changes manifested with typical osteopenia pathological changes. Our results may serve as a basis for the design of further studies using OVX goat as an animal model for postmenopausal osteoporosis.

Animals↗
PubMed1997

[Effects of L-glutamic acid, gamma-aminobutyric acid and their respective antagonists on spontaneous discharge of nucleus paragigantocellularis lateralis neurons in rats].

Using multibarrel microelectrode techniques, we studied the effects of iontophoretic application of L-glutamic acid (L-Glu), gamma-aminobutyric acid (GABA) and their respective antagonists DL-2-amino-5-phosphonovaleric acid (AP5), bicuculline (BIC) on the spontaneous discharge of the caudal half of nucleus paragigantocellularis lateralis (cPGCL) neurons (including respiratory related neurons) and the influences of AP5 and BIC on the effects of L-Glu and GABA respectively in 22 anesthetized spontaneously breathing Sprague-Dawley rats. The spontaneous discharges of all the cPGCL neurons tested were inhibited by GABA(n = 53). Most of the tested neurons were excitated by L-Glu (30/36). AP5 and BIC both showed three kinds of effects on the cPGCL neuronal spontaneous discharge; excitatory, inhibitory and no-effect. The excitatory effects of L-Glu and BIC and the inhibitory effects of GABA showed a dose-response relationship. AP5 could block partially the excitatory effect of L-Glu on a large part of neurons tested (14/19). BIC blocked, partially or completely, the inhibitory effect of GABA also on a large part of the neurons tested(18/24). The results implicate that there might exist endogenous L-Glu and GABA acting as neurotransmitters in the cPGCL area and excitatory amino acids (EAA, including NMDA and non-NMDA) and GABA-receptors on cPGCL neurons. These neurotransmitters and receptors may mediate the regulatory action of cPGCL on respiration and other functional systems.

2-Amino-5-phosphonovalerate↗
PubMed1997

[Optimal high-yield agronomic measures for Curcuma longa L].

Regression method of orthogonal conic substitution with factors was employed to build up a tuber yield simulation model. Three main measures (sowing time, plant population, application rate of fertilizer) affecting the tuber yield were analyzed by the mathematical model of three unknown second order orthogonal rotative regression. The optimal agronomic measures were obtained. The results indicate that sowing time and plant population play a important role in raising the tuber yield. Sowing time is clearly interrelated with plant population, and likewise, plant population application rate of fertilizer.

Fertilizers↗
PubMed1997

[Effect of cultivating measures on the tuber yield of Curcuma longa L].

The effect of cultivating measures on the tuber yield of Curcuma longa was observed. dibble planting has been proved move effective in raising the tuber yield than drill culture, and the dibble planting quantity has no effect on the tuber. The rational producing area, soil, seed tuber and so on were selected according to the experiments.

Methods↗
PubMed1997

[An animal model of non-hereditary Alzheimer's disease and its behavioral and pathologic changes].

An animal model of non-hereditary AD was built by lesioning nucleus basalis of Meynert (nbM) and to investigate the behavioral alteration by Morris water maze, the pathological changes by special staining for senile plaques(SPs), enzymatic cytochemical staining for AChE, and immunocytochemical staining for beta amyloid protein (beta AP) and tau protein. Transmission electron microscopic observation has also been made. Results showed: (1) loss of learning and memory ability; (2) occurrence of necrotic granules in cytoplasm and inclusion in axon hillock; accumulation of necrotic cell, and formation of SPs under light microscope; (3) accumulation of microtubules and formation of inclusion, increase of lysosome and edema and vacuolation of neurons and neuroterminals under electron microscopy; (4) decrease of synaptic density; (5) sharp decrease of AChE (acetylcholinesterase) positive fibers and neurons shown by immunocytochemical staining; (6) overexpression of beta AP and tau protein.

Acetylcholinesterase↗
PubMed1997

[Identification of realgar and arsenopyrite and their sublimates].

In this paper, two traditional Chinese medicinal minerals realgar and arsenopyrite, as well as their sublimates are identified in their nature, physical and optical properties, chemical compositions and trace elements. The result has shown that there are marked differences among realgar, arsenopyrite and their sublimates, and it should be particularly noted that the difference between the two sublimates will certainly affect the quality of the two minerals that are used as poisonous drug in China.

Arsenic Trioxide↗
PubMed1997

[Antilipid peroxidation and antiradiative action of glycosides in herba Cistanches].

The results showed that oral administration of GCs could markedly increase the activity of SOD in red blood cells as well as the contents of nucleic acid (DNA and RNA) in liver and kidney, decrease the contents of MDA in serum, markedly increase the activity of SOD in red blood cells as well as the contents of nucleic acid in the spleen of mice radio-induced by 60Co, and also lower the contents of MDA in liver. The results suggest that the protective effect of GCs on nucleic acid and antiradiative action may be related to its antilipid peroxidation.

Animals↗
PubMed1997

[Ontogeny of Curcuma longa L].

Based on the research of growth of organs, accumulation of dry matter, distribution of photosynthetic production and displacement of growth centre, the growth of turmeric can be divided into three stages. There are 13 leaves in the life of turmeric. Leaf formation takes place rapidly to form 8 leaves in the seedling stage. The leaf area and increase of dry matter per day in roots and leaves are smaller or lower in the seedling stage. In the daughter rhizome formation stage, NAR reaches the maximum (3.54/m2.d), and the leaf area reaches the maximum(3302.9 cm2/plant, LAI 4.95). Before the daughter rhizome formation stage, more than 75% of dry matters are distributed in leaves, and in the daughter rhizome formation stage, 50%-75% of dry matters are distrbuted in leaves. In the late growing period, more than 40% of dry matters are distributed in the daughter rhizome. The growth centre of turmeric changes two times in life. When CGRr is equal to CGRt, the crossing of CGRt and CGRr curves may be regarded as the evidence of the transfer of growth centre from leaves to daughter rhizome.

Pharmacognosy↗
PubMed1997

[A research on real-time ventricular QRS classification methods for single-chip-microcomputers].

Ventricular QRS classification is key technique of ventricular arrhythmias detection in single-chip-microcomputer based dynamic electrocardiogram real-time analyser. This paper adopts morphological feature vector including QRS amplitude, interval information to reveal QRS morphology. After studying the distribution of QRS morphology feature vector of MIT/BIH DB ventricular arrhythmia files, we use morphological feature vector cluster to classify multi-morphology QRS. Based on the method, morphological feature parameters changing method which is suitable to catch occasional ventricular arrhythmias is presented. Clinical experiments verify missed ventricular arrhythmia is less than 1% by this method.

Arrhythmias, Cardiac↗
PubMed1997

[Protective effect of schisanhenol (SAL) on oxygen free radical induced injury of spleen lymphocytes in mice].

In the present paper the effects of Sal, an active component isolated from Kadsura Longipenduculata Finet et Gagnep, on oxygen free radical induced injury of murine spleen lymphocytes in vitro and in vivo were investigated. The results showed that Sal at 1 x 10(-4) mol.L-1 significantly inhibited the decrease of GSH content induced by Fe(2+)-Vit C and the increase of MDA formation induced by Fe(2+)-Cys in murine spleen lymphocytes. The decrease of membrane fluidity of lymphocytes under lipid peroxidation induced by Fe(2+)-Vit C was prevented by Sal. The damage of the lymphocyte surfaces induced by Fe(2+)-Vit C was also markedly reduced by Sal. Administration of Sal 20 mg.kg-1.d-1 for 8 d significantly increased the GSH content of the spleen lymphocytes in mice under high oxygen-stress. Meanwhile, the compensative increase of SOD activity in the spleen lymphocytes was reversed. The results suggest that Sal may protect murine spleen lymphocytes from the injury induced by oxygen free radicals.

Animals↗
PubMed1997

[The effects of hypoxia on wavelet decomposition of event-related potential].

This study recorded the event-related potentials (ERP) of eleven healthy male subjects who were in the condition of acute altitude hypoxia caused by in halation of low oxygen mixture. The multiresolution wavelet transform and statistics were used to analyze the ERP. The result demonstrates that the detail components are sensitive to the hypoxia.

Acoustic Stimulation↗