Biomedical subjects

S Peng

Publications and source records attributed to S Peng.

At least 37 records · Page 2Linked to original sources

PubMed2001

[Association of apolipoprotein E gene polymorphism with early-onset coronary heart disease and its effect on plasma lipid levels].

OBJECTIVE: To detect the association of apolipoprotein E(apoE) gene polymorphism with early-onset coronary heart disease(CHD) and to evaluate the effect of apoE gene polymorphism on plasma lipid levels. METHODS: The apoE genotypes of 52 early-onset CHD patients (aged 38-55 years), 161 aged CHD patients and 180 controls were determined by PCR-RFLP. Plasma lipid levels were measured by using routine methods. RESULTS: Five genotypes of apoE, E3/3, E4/4, E3/2, E4/3 and E4/2 were detected in this study. Statistically differences in apoE4/3 and epsilon4 frequencies between early-onset and aged CHD patients and controls were seen (P<0.05). The frequency of epsilon4 in the early-onset CHD patients was higher than that in the aged CHD patients. epsilon4 and epsilon2 alleles also differently affected the plasma total cholesterol and low density lipoprotein cholesterol levels. CONCLUSION: These results suggest that apoE gene polymorphism is in association with the occurrence and development of early-onset CHD and it affects the plasma lipid levels.

Adult↗

PubMed2001

[Influence of elevated atmospheric CO2 concentration on photosynthesis and leaf nitrogen partition in process of photosynthetic carbon cycle in Musa paradisiaca].

The photosynthetic rate (Pn) in leaves of Musa paradisiaca grown under elevated CO2 concentration (700 +/- 56 microliters.L-1) for one week was 5.14 +/- 0.32 mumol.m-2.s-1, 22.1% higher than that under ambient CO2 concentration, while under elevated CO2 concentration for 8 week, the Pn decreased by 18.1%. It can be inferred that the photosynthetic acclimation to elevated CO2 concentration and the Pn inhibition occurred in leaves of M. paradisiaca. The respiration rate in light (Rd) was lower in leaves under higher CO2 concentration, compared with that under ambient CO2 concentration. If the respiration in light was not included, the difference in CO2 compensation point for the leaves of both plants was not significant. Under higher CO2 concentration for 8 weeks, the maximum carboxylation rate(Vcmax) and electron transportation rate (J) in leaves decreased respectively by 30.5% and 14.8%, compared with that under ambient CO2 concentration. The calculated apparent quantum yield (alpha) in leaves under elevated CO2 concentration according to the initial slope of Pn/PAR was reduced to 0.014 +/- 0.010 molCO2.mol-1 quanta, compared with the value of 0.025 +/- 0.005 molCO2.mol-1 quanta in the control. The efficiency of light energy conversion also decreased from 0.203 to 0.136 electrons.quanta-1 in plants under elevated CO2 concentration. A lower partitioning coefficient for leaf nitrogen in Rubisco, bioenergetics and thylakoid light-harvesting components was observed in plants under higher CO2 concentration. The results indicated that the multi-process of photosynthesis was suppressed significantly by a long-term (8 weeks) higher CO2 concentration incubation.

Carbon Dioxide↗

PubMed2001

[Species and species diversity in relation with restoration and persistence of degraded ecosystem functions].

Species diversity is an important character of an ecosystem, and keeps it to function. Species diversity and their communities provide human with essential ecosystem services, including nutrient cycling, biological productivity, trophic function, etc. Species diversity is tightly related with the ecosystem's ability to withstand stress and disturbance. Increasing biodiversity could enhance system stability. Compared to individual species and species number, functional group and functional diversity impose larger impact on system functioning, and are good approaches used to measure stability and to predict community change. Several forms with which the species act on ecosystem functioning were proposed and discussed in this paper. Understanding the relationship between species diversity and ecosystem function could guide the practice of restoring degraded ecosystem and maintaining its functions. Particularly, it provides basic ecological theories for "species assemblage" at initial stage of restoration.

Ecosystem↗

PubMed2001

[Antimetastatic effects of arginine-aspartate on salivary adenoid cystic carcinoma in vitro].

OBJECTIVE: To test the effects of arginine-aspartate (RD) on metastasis of salivary cystic carcinoma (SACC). METHODS: Highly metastatic SACC cell line SACC-LM was used in the study. The effect of RD on tumor cell-ECM adhesion was assayed by MTT technique. The effect of RD on invasion and migration of SACC-LM were evaluated using modified boyden chamber. RESULTS: RD inhibited tumor cell fibronectin adhesion at 5 mg/L concentration, but no effects on tumor cell laminin and tumor cell type IV collagen adhesion. RD inhibited the invasion at 1, 5, 25 mg/L, and inhibited the migration only at 25 mg/L. CONCLUSIONS: The result shows that the RD has an antimetastatic effect on SACC-LM cells in vitro.

Antineoplastic Agents↗

PubMed2001

[The development of computerized cardiac programmable stimulator].

This paper introduces a fully computerized cardiac programmable stimulator. With the visual interface of computer, the configuration and control of stimulation will be realized conveniently. Meanwhile, the current status and the waves during stimulation will be displayed in window real-time, which improved the visualization and availability in medical application. It has been proved that this system is simpler in operation and more functional than traditional cardiac programmable stimulators, and therefore it is valuable in medical applications.

Electric Stimulation↗

PubMed2001

[The development of an all-purpose medical electronic teaching instrument].

This paper introduces a kind of all-purpose medical electronic teaching instrument. According to the modularization design rule, a medical electronic teaching instrument integrated with information transfer, signal processing, keyboard monitoring and signal sampling, etc, can be realized. On the other hand, A/D, D/A, self-detecting of computer, collecting and testing of biological potentials, driving electromotor and generating functional signals, etc can also be realized by the related software based on the system. It has been proved that, by using single-chip processor and computer, the system can implement full-scale test and processing of biomedical signals so that operators can understand the principles and the construction of medical instruments more easily and deeply. Therefore, it is valuable in application of medical electronic coursesteaching, research and etc.

Computer-Assisted Instruction↗

PubMed2001

[Study of chemical constituents of essential oil from flowers of Mikania micrantha H.B.K].

The essential oil from flowers of Mikania micrantha H.B.K were extracted and its chemical constituents were analyzed by GC/MS. Forty-two compounds were identified and the main compounds with high contents were beta-cubebene (12.95%), allo-aromadendrene (11.67%), beta-caryophyllene (9.17%), 1H-inden-1-one, 5-(1, 1-dimethylethyl)-2, 3-(6.23%), beta-himaohalene (4.56%), trans-alpha-bergamotene (4.09%), limonene (3.68%), beta-ocimene (2.53%).

Azulenes↗

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↗

PubMed2001

[Diagnosis and treatment of congenital biliary duct cyst: twenty-year experience].

OBJECTIVE: To summarize the experience in diagnosis and treatment of congenital biliary duct cyst. METHODS: Clinical data from 108 patients treated from 1980 to 2000 were analyzed retrospectively. RESULTS: Abdominal pain, jaundice and abdominal mass were presented in most pediatric patients. Clinical symptoms in adult patients were non-specific, resulting in delayed diagnosis frequently. Fifty-seven patients (52.7%) had coexistent pancreatic biliary disease. Carcinoma of the biliary duct occurred in 18 patients (16.6%). Ultrasonic examination was performed in 94 patients, ERCP in 46, and CT in 71. All of the patients were correctly diagnosed before operation. Abnormal pancreatobiliary duct junction was found in 39 patients. Before 1985, the diagnosis and classification of congenital biliary duct cyst were established by ultrasonography preoperatively and confirmed during operation. The main procedure was internal drainage by cyst-enterostomy. After 1985, the diagnosis was decided with ERCP and CT, the procedure was cyst excision with Roux-en-Y hepaticojejunostomy. In 1994, we used a new and simplified operative procedure to reduce the risk of malignancy of choledochal cyst. Retrograde infection of the biliary tract the major postoperative complication, could be controlled by the administration of antibiotics. CONCLUSIONS: The concept in diagnosis and treatment of congenital choledochal cyst has been changed greatly. CT and ERCP are of great help in the classification of the disease. Currently, cyst excision with Roux-en-Y hepaticojejunostomy is strongly recommended as the treatment of choice for patients with type I and IV cysts. Piggyback orthotopic liver transplantation is indicated for type V cysts (Caroli's disease) with frequently recurrent cholangitis, resulting in biliary cirrhosis.

Adolescent↗

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↗