Biomedical subjects

S Peng

Publications and source records attributed to S Peng.

At least 37 records · Page 2Linked to original sources

PubMed2001

[Determination of 10 elements in the 12 kinds of Chinese traditional medicines by AAS].

The 10 kinds of inorganic elements were determined in 12 kinds of Chinese traditional medicines. The relation showed that there were numerous inorganic elements in the traditional chinese medicines. The relation between these inorganic elements and the efficacies of these medicines was studied and the efficacies of these Chinese traditional medicines were discussed. The efficacies of these traditional medicines were greatly influenced by the content of inorganic elements. To guarantee the efficacies of these traditional medicines, the reasonable control lines concerned with the content of inorganic elements shall be established and the lines will be discussed in the future.

Calcium↗

PubMed2000

Abnormal chloride and potassium conductances in cultured embryonic tongue muscle from trisomy 16 mouse.

Trisomy 16 (Ts16) mouse is considered an animal model of Down syndrome (human trisomy 21). Whole-cell patch-clamp was used to evaluate potassium and chloride currents of cultured tongue muscle cells from fetal Ts16 and diploid mice. No difference was found in membrane capacitance between the two groups. K(+) and Cl(-) currents were pharmacologically isolated. K(+) conductance was reduced by 31% in Ts16 cells (373 pS/pF) compared with diploid cells (539 pS/pF). Cl(-) conductance was 51% larger in Ts16 cells (103 pS/pF) compared with diploid cells (68 pS/pF). However kinetics for K(+) and Cl(-) currents did not differ between the cell types. An increase in Cl(-) conductance and a decrease in K(+) conductance in Ts16 muscle cells, if present in muscle of Down syndrome subjects, might account for the observed hypotonia in these subjects.

Animals↗

PubMed2000

Nanotube molecular wires as chemical sensors

Chemical sensors based on individual single-walled carbon nanotubes (SWNTs) are demonstrated. Upon exposure to gaseous molecules such as NO(2) or NH(3), the electrical resistance of a semiconducting SWNT is found to dramatically increase or decrease. This serves as the basis for nanotube molecular sensors. The nanotube sensors exhibit a fast response and a substantially higher sensitivity than that of existing solid-state sensors at room temperature. Sensor reversibility is achieved by slow recovery under ambient conditions or by heating to high temperatures. The interactions between molecular species and SWNTs and the mechanisms of molecular sensing with nanotube molecular wires are investigated.

Journal Article↗

PubMed2000

Quantification of cholesteryl esters in human and rabbit atherosclerotic plaques by magic-angle spinning (13)C-NMR.

Accumulation of cholesteryl esters (CEs) is a key event in the formation of atherosclerotic plaques. More recent work suggests a role for CEs in plaque rupture leading to thrombosis, which can result in an acute event such as myocardial infarction or stroke. In this study, we present nuclear magnetic resonance (NMR) protocols for quantification of CEs in plaques in situ. Total CEs quantified by (13)C magic-angle spinning (MAS) NMR in excised plaques from human carotid arteries and rabbit aortic arteries were in good agreement with the amounts determined by subsequent standard chemical assays. The latter analysis is disadvantageous because it requires that plaque lipids be extracted from the tissue, resulting in the loss of all phase information of CEs as well as other major plaque components. With our MAS-NMR protocol, the plaque components are preserved in their native phases. Combining MAS and off-MAS NMR, we were able to quantitatively distinguish isotropic (liquid) CEs from anisotropic (liquid-crystalline) CEs in plaque tissues. In a recent study, we applied a different (13)C MAS-NMR protocol to quantify crystalline cholesterol monohydrate in plaques. Together, these 2 studies describe a new, noninvasive MAS-NMR strategy for the identification and quantification of the major lipid components in plaques in situ. This approach will be useful for investigation of the relationship between plaque rupture and specific lipids in their biologically relevant phases.

Animals↗

PubMed2000

[Genetic variation of geographical provenance of Pinus massoniana--review and analysis].

Pinus massoniana is a significant tree species constituting the subtropical forests in China. Based on morphological, physio-ecological, chromosome, and molecular levels, the genetic variation of geographical provenance of P. massoniana and its distribution were reviewed, and the methodologies on genetic diversity and the genetic variation patterns of geographical provenance of P. massoniana were synthetically analyzed. The Key problems on molecular ecology of P. massoniana were discussed.

Ecology↗

PubMed2000

[Nutrient content in litterfall and its translocation in plantation forests in south China].

The amounts of litterfall, nutrient content in it and leaves of five plantation forests in south China were determined. The order of litterfall biomass was in sequence of Acacia mangium (11.1 t.hm-2) > Pinus elliotii (7.3 t.hm-2) > Schima superba (6.5 t.hm-2) > Acacia auriculaiformis (4.8 t.hm-2) > Eucalyptus citriodora (2.6 t.hm-2). A. mangium returned soil much more nutrient to soil through litterfall than other forests did. N, P and K were largely translocated from senescing leaves for all the five forests, and especially for A. mangium. Nutrient translocated varied greatly with seasons. The translocation of other elements was not definite.

Biomass↗

PubMed2000

[A comparative study on chlorophyll content, chlorophyll fluorescence and diurnal course of leaf gas exchange of two ecotypes of banyan].

The morphological differences, chlorophyll contents, fluorescence and diurnal course of leaf gas exchange between terrestrial banyan and amphibious banyan were compared with pot culture. The amphibious banyan possesses well developed aerial and hydro-adventitious roots, and wider leaf with inclination of evolution toward mesophytic traits. The chlorophyll content of terrestrial banyan was higher than that of amphibious banyan. The diurnal course of leaf gas exchange indicated that net photosynthetic rate of terrestrial banyan was slightly higher than that of amphibious banyan grown in water, but much higher than that grown in soil. The amphibious banyan grown in water had the highest transpiration rate, the terrestrial banyan had a lower one, and the amphibious banyan grown in soil had the lowest. Linear regression analysis showed a positive correlation between net photosynthetic rate and stomatal conductance, implying that the stomatal conductance was dominant factor controlling the gas exchange. In this study, the term of intrinsic water use efficiency (net photosynthetic rate/stomatal conductance ratio, Intrinsic WUE) was applied to describe the photosynthesis and water properties, and the result showed that it was a more suitable measure compared to the usual WUE(net photosynthetic rate/transpiration rate). Among the three banyan plants examined, the amphibious banyan had the highest intrinsic WUE.

Adaptation, Physiological↗

PubMed2000

[Concept of ecosystem management and its essential elements].

Ecosystem management originates from the tradition fields of natural resources management and utilization, and develops in the 1990's. Based on our best understanding of the ecosystem composition, structure and function, and in definite spatiotemporal scales, it integrates human values and social-economic principles into managing ecosystems to resotre and/or sustain ecosystem integrity and sustainability. Ecosystem management requires the collection of field data and the monitoring of ecosystem dynamics at multiple scales. The essential elements of ecosystem management include clear management goals, definite ecological boundaries and units, sound ecological understanding, appropriate scale and hierarchic structure, understanding of ecosystem uncertainty, adaptive management, cooperation between agency and individuals, and viewing human and its value as ecosystem components. The goal of ecosystem management focuses on ecosystem sustainbility.

Ecosystem↗

PubMed2000

[The establishment of the model for differential diagnosis of borderline cases with anterior crossbite using fuzzy set theory].

OBJECTIVE: To introduce the fuzzy set theory to orthodontics by using the diagnostic information drawn out from the diagnosed cases to solve the problem of borderline- case diagnosis. METHOD: Lateral cephalometric radiographs of 107 anterior crossbite patients in early permanent dentition were traced, measured, and 31 variables calculated. Diagnosis was made by experienced specialists and the cases were divided into three groups: dental anterior crossbite (52 cases), borderline cases (22 cases) and skeletal anterior crossbite (33 cases). Among 85 cases with accurate diagnosis we selected 70 cases to establish 6-factor model using stepwise discriminant analysis. This afforded 100 percent correct respective check and the predictive diagnosis of the other 15 cases showed that its correction rate was 93.3 percent which proved that most useful information was included. Then the contributions of the six variables were calculated and we established two sets: skeletal anterior crossbite set and dental anterior crossbite set with skeletal and dental means to be their thresholds. For each case the individual measurements of the six variables were standardized and afterwards transferred into constituent ratio and at the same time their degrees of membership of these two sets were calculated according to the distance between its location and the two thresholds. Using this fuzzy model we got the individual scores of the two sets. The diagnosis of the patient was coincident with the set of higher scores. This model was testified by 85 cases with accurate diagnosis and its correction was absolute. RESULT: 22 borderline cases were diagnosed by this model. CONCLUSION: The two-set difference were far less than that of the cases with accurate diagnosis which prove the model was reasonable.

Dentition, Permanent↗

PubMed2000

[Ventricular wave identification in epicardial mapping system using wavelet transform].

A novel method for the identification of ventricular wave based on wavelet transform is presented. First, "Multi-Scale Intersectional Search" is adopted for analysis of wavelet transform coefficients on some different scales, then adaptive detection is used on this basis. The results of practice show that it has a discrimination of 94.5%, and is obviously superior to any routime method.

Algorithms↗

PubMed2000

[Direct determination of rare earth elements in rare earth chloride and light rare earth oxide by ICP-AES].

ICP-AES was used for the direct determination of 15 rare earth elements in synthetic solutions and real sample. Spectral interferences between REEs in the mixtures of rare earth were investigated with a high-resolution echelle spectrometer and suitable analytical lines of 15 rare earth elements were selected. The Multicomponent Spectral Fitting(MSF) models were made. The method was used to remove spectral interferences and background. The factors influence the modes were discussed. The influences of acidity and ICP parameters were investigated. The compromise condition of simultaneous determination of 15 REEs was selected. Axially viewed ICP torch was used to determine 15 REEs, The detection limits are Y 0.21 microgram.L-1, La 9.1 micrograms.L-1, Ce 14.1 micrograms.L-1, Pr 1.9 micrograms.L-1, Nd 7.8 micrograms.L-1, Tm 0.37 microgram.L-1, Yb 0.12, Lu microgram.L-1, Ho 0.06 microgram.L-1, Er 0.06 microgram.L-1, Tb 0.53 microgram.L-1, Sm 1.14 micrograms.L-1, Eu 0.09 microgram.L-1, Dy 0.08 microgram.L-1, Gd 0.30 microgram.L-1. The recoveries of this procedure are between 98.4% and 101.7%. The RSD is within 2%. The method is rapid and accuracy.

English Abstract↗

PubMed2000

[Spectrometric determination of nutritional elements in the medicine-food flowers].

A study was carried out on the contents of nutritional elements in some medicine-food flowers by atomic absorption spectrometry. The results showed that flowers contain much more contents Fe, Ca, Mg and Co. The range of the average recovery in this method is 94%-108%, which indicate that the method we used is practicable. And flower is a kind of typical food source of containing high content of K and low content of Na. It is worth much more comprehensive utilization.

Asteraceae↗

PubMed1999

An ancient family of human endogenous retroviruses encodes a functional homolog of the HIV-1 Rev protein.

The human endogenous retrovirus K (HERV-K) family of endogenous retroviruses consists of approximately 50 proviral copies per haploid human genome. Herein, the HERV-Ks are shown to encode a sequence-specific nuclear RNA export factor, termed K-Rev, that is functionally analogous to the HIV-1 Rev protein. Like HIV-1 Rev, K-Rev binds to both the Crm1 nuclear export factor and to a cis-acting viral RNA target to activate nuclear export of unspliced RNAs. Surprisingly, this HERV-K RNA sequence, which is encoded within the HERV-K long terminal repeat, is also recognized by HIV-1 Rev. These data provide surprising evidence for an evolutionary link between HIV-1 and a group of endogenous retroviruses that first entered the human genome approximately 30 million years ago.

Carrier Proteins↗

PubMed1999

Occupational health survey on workers exposed to 2-bromopropane at low concentrations.

BACKGROUND: Recent case studies in Korea and animal studies revealed the reproductive and hematopoietic toxicity of 2-bromopropane introduced into workplaces as an alternative to ozone-layer depleting chlorofluorocarbons. We aimed to clarify the dose-effect relationship of 2-bromopropane in workers. METHOD: The exposure concentration of 2-bromopropane and hematological indices, hormonal levels, menstruation status, and sperm indices were examined in 25 workers (11 males, 14 females) at a 2-bromopropane factory. Regression analyses of the examined indices against time-weighted average (TWA) of exposure concentration were conducted. RESULTS: Amenorrhea or polymenorrhea was observed only in older females. Hematological indices had a significant relation with TWA of exposure concentration in females with normal menstruation. However, no other indices showed any significant relation with TWA of 2-bromopropane. CONCLUSIONS: No severe cases of reproductive or hematopoietic disorders were found at less than 10 ppm (TWA), but a possible adverse effect of 2-bromopropane on hematopoiesis could not be disproved.

Adult↗

PubMed1999

Autoreactive T cells in murine lupus: origins and roles in autoantibody production.

The conventional paradigm to explain systemic lupus erythematosus (SLE) is that disease results from tissue deposition of pathogenic autoantibodies and immune complexes, secondary to activation of autoreactive B cells in the context of help from alphabeta T cells. Recent work in murine lupus has confirmed this notion and demonstrated that autoantigen-specific alphabeta T cells are absolutely required for full penetrance of disease, with such autoreactive alphabeta T cells, even in Fas-intact mice, likely arising from defects in peripheral tolerance. These studies have also revealed a network of regulation that also involves nonclassical pathogenic and downregulatory alphabeta and gammadelta T cells, suggesting that the lupus immune system involves more complex interactions than the conventional paradigm suggests.

Animals↗

PubMed1999

Construction and production of fluorescent papillomavirus-like particles.

The green fluorescent protein (GFP) from the jellyfish Aequorea victoria has attracted widespread interest since it was demonstrated to be fluorescent in vivo when expressed in other organisms. In order to investigate papillomavirus life cycle which hampered by the unavailability of conventional cell culture system, we constructed a chimeric bovine papillomavirus (BPV) type 1 virus-like particles (VLPs) containing GFP. It was found that fluorescent VLPs could be assembled from L2 protein in which GFP is inserted into the N-terminal region of L2 (aa 88). The fluorescent VLPs could also be assembled from a GFP/L2 fusion protein in which part of the L2 sequence had been deleted. In vitro, fluorescent VLPs could bind to CV-1 cells, and this VLP/cell interaction could be analyzed by FACS assay. These results demonstrated that GFP could incorporate into BPV1 VLPs without disruption of the VLP structure. Fluorescent VLPs might be a useful tool for study of papillomavirus virus/cell interaction.

Baculoviridae↗

PubMed1999

Synthesis of novel chelating agents and their effect on cadmium decorporation.

A series of novel dithiocarbamates, disodium salts of N-glucamyl-N-dithiocarboxyl-amino acids, were synthesized, and their usefullness as an antagonist of cadmium intoxication was investigated. These chelating agents were found to be effective in both acute and repeated exposure cadmium poisoning. The results showed that the cadmium mobilizing properties of disodium N-(2,3,4,5, 6-pentahydroxylhexyl)-N-dithiocarbamate-L-threoninate and disodium N-(2,3,4,5,6-pentahydroxylhexyl)-N-dithiocarbamate-L-cysteinate are clearly superior to those of sodium N-(4-methoxybenzyl)-D-glucamine-N-carbodithioate (MeOBGDTC) revealed in the experiments described here. The toxicity of these novel compounds is modest, and their effect on the concentrations of essential metal ions in the renal cortex is quite small in comparison with that of a group treated with cadmium only. The new dithiocarbomates were identified by MS, rather than by elemental analysis, as they were extremely hygroscopic.

Animals↗

PubMed1999

Capture ElISA and in vitro cell binding assay for the detection of antibodies to human papillomavirus type 6b virus-like particles in patients with anogenital warts.

To investigate human papillomavirus (HPV) virus-like particle (VLP)-specific antibody responses among anogenital warts patients, a VLP-based capture ELISA was established. Twenty-six percent (35/134) of control subjects and 50.0% (39/78) of patients with current anogenital warts showed IgG seropositivity to HPV 6b VLPs. HPV 6b VLP-specific antibody responses recognised native VLPs only, and had no cross-reaction with HPV type 16 VLPs. No differences in reactivity were observed between L1 and L1 + L2 VLPs, suggesting that L2 contributes little to the total immunogenicity of the papillomavirus virion. A VLP-cell binding assay was also established. Some sera from patients with anogenital warts specifically inhibited VLP binding to the surface of epithelial cells, suggesting that these antibodies might be functionally neutralising. These data show that serological responses to HPV 6b VLPs were induced among some but not all patients with anogenital warts, and give a proportional estimate of infection in the community.

Adolescent↗