Biomedical subjects

Na Li

Publications and source records attributed to Na Li.

At least 55 records · Page 3Linked to original sources

PubMed2006

Taraxasterane- and ursane-type triterpenes from Nerium oleander and their biological activities.

Two new taraxasterane-type triterpenes, 20beta,28-epoxy-28alpha-methoxytaraxasteran-3beta-ol (1) and 20beta,28-epoxytaraxaster-21-en-3beta-ol (2), were isolated from an ethyl acetate extract of the leaves of Nerium oleander, together with ursane-type triterpenes, 28-nor-urs-12-ene-3beta,17beta-diol (3) and 3beta-hydroxyurs-12-en-28-aldehyde (4). The structures of 1 and 2 were established on the basis of their spectroscopic data. Anti-inflammatory activity of 1-4 was examined on the basis of inhibitory activity against the induction of intercellular adhesion molecule-1 (ICAM-1). Cytotoxic activity of 1-4 was evaluated against four human cell lines, A-549, WI-38, VA-13, and HepG2 cells.

Anti-Inflammatory Agents, Non-Steroidal↗

PubMed2006

Ethanol-related traits in mice selectively bred for differential sensitivity to methamphetamine-induced activation.

Acute drug stimulation has been proposed to be an endophenotype for drug abuse. The authors previously reported the short-term selective breeding of lines of mice for low (LMACT) and high (HMACT) stimulation to methamphetamine (MA). These mice were used to examine whether common genes influence the locomotor response to MA and ethanol. Additionally, the authors tested these mice for ethanol drinking, locomotor sensitization, and clearance. LMACT mice were less stimulated by ethanol and consumed more ethanol than HMACT mice, but the lines did not differ in ethanol-induced sensitization. A small difference in ethanol clearance rate (0.1 mg/ml/h) likely had little impact on behavior. Some common genes may influence the locomotor response to MA and ethanol, as well as ethanol drinking.

Alcohol Drinking↗

PubMed2006

Variations of bacterial community structure in flooded paddy soil contaminated with herbicide quinclorac.

The denaturing gradient gel electrophoresis (DGGE) method was applied to determine the relative genetic complexity of microbial communities in flooded paddy soil treated with herbicide quinclorac (3,7-dichloro-8-quinoline-carboylic acid). The results obtained showed a significant effect of quinclorac on the development of bacterial populations in soils contaminated with different concentrations of the herbicide at the early time after application. In general, however, the number of populations of the same soil sample treated with the same concentration of the quinclorac differed obviously with increasing incubation time within the early 8 weeks. The scale of differences in banding patterns-showed that the microbial community structures of the quinclorac-treated and non-quinclorac-treated soils were not significantly different after 21 weeks of incubation. Quantification, as demonstrated in this paper, was studied by establishing dose-response relationships. Significant pattern variations were quantified. Prominent DGGE bands were excised, cloned and sequenced to gain insight into the identities of predominant bacterial populations. The majority of DGGE band sequences were related to bacterial genera Clostridium, Sphingobacterium, Xanthomonas and Rhodococcus.

Bacteria↗

PubMed2006

Delay discounting predicts behavioral sensitization to ethanol in outbred WSC mice.

BACKGROUND: Alcoholic individuals discount the value of future rewards more steeply than social drinkers, which is viewed as symptomatic of higher levels of impulsivity. However, the mechanisms underlying this difference are unknown. This study examined 2 hypotheses about the relationship between discounting and ethanol's effects in mice: (1) steep discounters are less sensitive to the initial stimulant-like effects of ethanol and (2) steep discounters exhibit greater behavioral adaptation to stimulant effects with repeated ethanol exposure. METHODS: An adjusting amount procedure was used to assess discounting as a function of delay in ethanol-naïve genetically heterogeneous WSC mice. Mice chose between a small amount of sucrose solution delivered immediately and 19.5 microL delivered following a delay (0, 2, 4, 8, or 12 seconds, varied between sessions). Within sessions, the amount (microL) of immediate sucrose was adjusted until animals became indifferent between the immediate and specific delayed reward. Hyperbolic discount functions were fitted to quantify the degree of delay discounting. Then, in a within-subjects design over 13 days, mice received a pattern of daily injections of saline or ethanol, and after certain treatments their locomotor activity was assessed for 15 minutes. RESULTS: Animals with steeper discount functions (greater impulsivity) tended to exhibit less locomotor stimulation on their initial exposure to ethanol. However, steeper discounting was positively associated with increases in locomotor activity after repeated exposure (sensitization), indicating that steep discounters showed higher levels of sensitization to the stimulating effects of ethanol. CONCLUSIONS: These results suggest 2 behavioral effects of ethanol, associated with an increased risk for alcohol abuse, that are associated with variations in delay discounting.

Adaptation, Psychological↗

PubMed2006

Comparative proteomic analysis between the invasive and commensal strains of Staphylococcus epidermidis.

Staphylococcus epidermidis is one of the major causative agents for nosocomial infections. To reveal the pathogenesis factors, we performed the comparative proteomic analysis of invasive ATCC35984 and commensal ATCC12228 strains by two-dimensional gel electrophoresis and matrix-assisted laser desorption/ionization-time of flight-mass spectrometry. The differentially expressed proteins were involved in carbohydrate metabolism, sugar binding, lipid degradation and amino acid binding. In addition, we demonstrated that the trap gene was transcribed by 3.657+/-0.156 (P<0.01) -fold higher in ATCC35984 than in ATCC12228. Levels of accumulation-associated protein (AAP) were found to be low by the immuno-dot blotting assay in ATCC12228, which is unable to form biofilm. Our results suggest that the target of RNAIII activating protein and AAP may contribute to S. epidermidis virulence and biofilm formation.

Amino Acids↗

PubMed2006

Effects of orexins on myoelectric activity of sphincter of Oddi in fasted rabbits.

AIM: To investigate the effects of peripheral orexins on myoelectric activity of the sphincter of Oddi (SO) in fasted rabbits, and carry out a preliminary investigation into the mechanisms underlying these effects. METHODS: Myoelectric activity of SO in fasted rabbits was recorded before and after intravenous or local application of orexins. The effects of intravenous atropine on orexin-increased myoelectric activity of SO were tested. RESULTS: Myoelectric activity of SO was activated by both intravenous and local injection of orexin-A or orexin-B. Intravenous application of atropine completely inhibited the excitatory effect of orexins on SO. CONCLUSION: Peripheral application of orexins can increase myoelectric activity of SO in fasted rabbits, which is partially associated with the activation of the cholinergic pathway.

Animals↗

PubMed2006

High doses of bifendate elevate serum and hepatic triglyceride levels in rabbits and mice: animal models of acute hypertriglyceridemia.

AIM: To investigate the effects of bifendate on serum and hepatic lipids level in rabbits and mice. METHODS: Animals were administered bifendate [powdered pill suspended in 0.5% sodium carboxymethylcellulose (CMC)] at increasing doses (0.25-1 g/kg, ig). Blood lipid and apolipoprotein levels were measured using commercially available assay kits. RESULTS: The treatment of rabbits with a single dose of bifendate (0.3 g/kg) caused a time-dependent and biphasic change in serum triglyceride (TG) levels, with the value reaching a maximum (3-fold increase compared to the baseline value) between 24 and 36 h post-dosing. When mice were orally treated with bifendate (0.25-1 g/kg), serum TG levels increased by 39%-76% and 14%-39% at 24 and 48 h post-dosing, respectively. When given at daily doses of 0.25 and 1 g/kg for 4 d, bifendate increased serum TG levels (56%-79%), with concomitant elevations in apolipoprotein A-I and apolipoprotein B levels at 24 h after the last dosing. TG levels were also increased (11%-43%) in liver samples of mice receiving single or multiple doses of bifendate. However, bifendate treatment caused slight reductions in serum and hepatic total cholesterol levels (9%-13%). The hypertriglyceridemia induced by bifendate was ameliorated by fenofibrate but not inositol nicotinate treatment in mice. CONCLUSION: The findings suggest that bifendate treatment at high oral doses can cause an acute elevation in serum and hepatic TG levels.

Animals↗

PubMed2006

[Expression of human granulysin in murine macrophages and its effects on cell damage and apoptosis].

AIM: To construct an eukaryotic expression vector pBudCE4.1/GLS encoding human granulysin(GLS) derived from activated CTLs and observe its effects on cell damage and apoptosis when expressed in macrophages of various murine germ lines. METHODS: The gene sequence coding GLS carried on pEGFP-C1/GLS was subcloned into pBudCE4.1 plasmid and then transfected into different murine macrophages. The expression of GLS was detected by RT-PCR and immunocytochemical staining. The impairment and apoptosis of the host cells was assesed by measuring LDH in culture media and fluorescent staining of nuclear DNA, respectively. RESULTS: The pBudCE4.1/GLS recombinant containing accurate ORF of GLS was obtained and successfully expressed in the target cells at 48 h after transfection. No obvious effects on cell damage and apoptosis was detected during this course. CONCLUSION: The gene coding human GLS can be expressed in murine macrophages. The expressed product has no obvious effects on cell damage and apoptosis.

Animals↗

PubMed2006

[Research progress on chemical constituents of Laggera plants in China].

Laggera plants are traditionally used as folk medicine to treat bacterial infection, inflammation and fever in China. Three species, Laggera alata, L. intermedia and L. pterodonta, grow in China. Modem clinical studies show that L. pterodonta is a good medicine against inflammation. More than 100 compounds were obtained from these plants. In order to assist in medicinal application of this species of plants, progresses made in this field are systemically reviewed in this article.

Asteraceae↗

PubMed2006

[Dynamic analysis of the heat shock protein 60 and its gene expression in Thermoanaerobacter tengcongensis induced by temperature increase].

Heat shock protein 60 (HSP60) is one of the important chaperonins, which can assist proper protein folding and configuration,and can prevent denaturation and degradation of proteins as well. It was found that HSP60 in Thermoanaerobacter tengcongensis (T. tengcongensis) was typically temperature-dependent with the highest protein expression at 80 degrees C. To understand the molecular mechanisms of thermophiles in their responding to heat stress, further investigation was conducted to examine the dynamic expression of HSP60 gene induced by higher temperature. The T. tengcongensis cells cultured at optimal temperature (75 degrees C) were transferred to 80 degrees C followed by taking the aliquots at different time intervals. To monitor the expression levels of HSP60 mRNA and protein, these bacterial gene products were analyzed by two-dimensional electrophoresis, MALDI-TOF, HPLC-MS/MS, Western blot and quantitative PCR. The experimental data were calculated statistically and quantitatively, which indicate that the HSP60 protein increases steadily and significantly within 4h period after temperature raised, but its mRNA level is shown as a peak shape change within 1h. Obviously, the expression response of HSP60 protein to heat stress is significantly slower than that of its mRNA expression. Additionally, the expression extent of HSP60 mRNA and protein induced by raised-temperature is very different. In E. coli strains, the expression of HSP60 is usually regulated by the sigma32 factor, which disassociates with DnaK immediately when the environmental temperature elevated. Since the genome of T. tengcongensis contains two sigma32 genes, thus, it is likely that both bacteria share the similar mechanisms which regulate HSP60 transcription responding to the changes of temperature. Interestingly, the mRNA of HSP60 drops down about 70% within 30m responding to heat shock, but goes to the increased expression after then. Although this phenomenon is hard to explain based upon the current theory, it is plausible that the transcription in T. tengcongensis is temporally inhibited due to the culture temperature sharply raised.

Bacterial Proteins↗

PubMed2006

[Endoscopic optic nerve decompression in traumatic optic neuropathy: analysis of 72 cases].

OBJECTIVE: To review the effects of optic nerve decompression by endoscopic technique in traumatic optic neuropathy. METHODS: Seventy-two patients (73 eyes) with traumatic optic neuropathy which were treated with large dose of glucocorticoid but inefficacious were undergone endoscopic optic nerve decompression. The days from injury to surgery were 1-57 d. Among that, < or = 3 d 15 cases, 4-7 d 37 cases, 8-10 d 9 cases, 11-15 d 5 cases, 16-30 d 5 cases, >30 d 1 cases. The vision of pro-operation: with light perception or higher grades 18 eyes; with no light perception 55 eyes. RESULTS: All patients were followed up for more than 3 months. Fourty-six of 73 eyes had improvements in visual acuity, the total effective rate was 63.01%. Thirty-one of 55 eyes with no light perception had raises in visual acuity (56.36%). Fifteen of 18 eyes with light perception or higher grades had improvements (83.33%). No complication had happened. CONCLUSIONS: Endoscopic optic nerve decompression is an appropriate technique for patients with traumatic optic neuropathy. Even though the patient has injured in longer time and high-dose steroid treatment has failed, optic nerve decompression may improve visual acuity.

Adolescent↗

PubMed2006

The regulatory role of dendritic cells in the immune tolerance.

Immune homeostasis is important for the protection of a host from pathogen aggression, as well as for preventing autoimmunity. Dendritic cells (DCs), the most potent antigen presenting cells, are critical in innate, adaptive immunity and in central tolerance. Recently, their involvement in peripheral tolerance has been shown. Whether DCs induce immunity or tolerance depends on their state of maturation. Different subsets of tolerogenic DCs have been identified in vivo, either in physiological, or pathological conditions, such as tumors, or GVHD. Moreover, tolerogenic DCs can be generated in vitro, by using different culture conditions, such as IL-10 or TGF-beta. In our study, we obtained tolerogenic DCs, by culturing them in the presence of human mesenchymal stem cells (MSCs).

Animals↗

PubMed2006

[Study on the method of rapid quality control of aqueous solution of flos lonicerae japonicae extraction in the preparation of qingkailing injection].

To establish a rapid and accurate on-line quality control method for aqueous solution of Flos Lonicerae Japonicae extraction (ASFLJE) in the preparation of Qingkailing injection, the wavelength of UV original spectrum and its first derivative spectrum of ASFLJE were scanned. The most suitable spectrum type and wavelength correlated with the chlorogenic acid content in ASFLJE determined by RP-HPLC were chosen to build a regress model. The UV equation for predicting chlorogenic acid content in ASFLJE was established. Other 10 batches of ASFLJE were used for testing the on-line prediction results by comparison of the values of chlorogenic acid content determined by HPLC and predicting equation respectively. The most suitable wavelengths correlated with chlorogenic acid content were 294 nm (r = 0.991 9, n = 28) in the original UV spectrum and 316 nm (r = 0.995 9, n = 28) in the first derivative spectrum respectively. The predicting equation of chlorogenic acid content was: c(mg x mL(-1)) = 506. 254 3 x A316 nm + 0.177 1 (r = 0.995 9, n = 28). This predicting equation is credible and accurate, as tested by HPLC method (r = 0.991 5, n = 10). The prediction results of chlorogenic acid content were: the chlorogenic acid content in probable 90 percent ASFLJE was: 0.4-4.0(mg x mL(-1)). This method is rapid, simple and accurate, and can be used for the on-line quality control of ASFLJE in Qingkailing injection preparation.

Chlorogenic Acid↗

PubMed2006

[Spectral properties of carbazole molecules and three-photon induced lasing].

Spectral properties of a series of new heterocyclic molecules were studied in the present work. The spectral experimental results show that the two-photon absorption cross-sections of these new molecules are dependent on their charge transfer dipole moments, which relate to the donor acceptor end groups. At high density pumping, the spectral and temporal properties of the high directional emission of a new molecule with two-photon absorption cross-section of 617.3 GM demonstrate that three-photon induced lasing occurs.

English Abstract↗

PubMed2006

[The application of multifactor dimensionality reduction for detecting gene-gene interactions].

OBJECTIVE: To introduce the application of Multifactor Dimensionality Reduction (MDR) method for detecting gene-gene interactions in genetic case-control studies. METHODS: A brief overview on basic steps involved in the implementation, theoretical details, available software as well as the use and features of the MDR method were discussed based on a practical research case. RESULTS: Advantages of MDR were compared to the conventional statistical approaches, showing that MDR method was a novel, nonparametric, genetic model-free approach that was developed specifically for detecting gene-gene interactions. Theoretical and empirical studies suggested that MDR was having reasonable power for detecting gene-gene interactions. Applications of MDR method had found the evidence of gene-gene interactions in several diseases such as sporadic breast cancer, atrial fibrillation and essential hypertension. CONCLUSION: MDR method could be used for detecting gene-gene interactions in genetic case-control studies as having great advantages versus the conventional statistical approaches.

Epistasis, Genetic↗

PubMed2006

[Inhibitory effects of 10-23 deoxyribozyme targeting ICL gene on the expression of isocitrate lyase and the infection of Mycobacterium tuberculosis in macrophages].

OBJECTIVE: To investigate the inhibitory effects of the 10-23 deoxyribozyme (DRZ) targeting ICL gene on the expression of isocitrate lyase (ICL) and the survival of Mycobacterium tuberculosis in macrophages. METHODS: Five 10-23 DRZ targeting ICL genes (DZ1-DZ5) were designed according to the predicted secondary structure of Mycobacterium tuberculosis ICL mRNA. Their cleavage activity and specificity were identified in cell free conditions. Then Mycobacterium tuberculosis pretreated with DZ4 with or without subinhibitory concentration of isoniazid (INH) were used to infect THP-1 cells. The bacterial burden of the infected THP-1 cells was monitored at indicated times after infection. The effect of 10-23 DRZ on the growth of Mycobacterium tuberculosis in vitro was also assayed by plating Mycobacterium tuberculosis treated with INH alone or DZ4 plus INH on M7H10 agar directly. RESULTS: Four of the five designed 10-23 DRZ, DZ1, DZ3, DZ4 and DZ5 could cleavage ICL mRNA efficiently and specifically. Treating Mycobacterium tuberculosis with 5 micromol/L DZ4 plus subinhibitory concentration of INH decreased the expression of ICL dramatically, by 34.9% - 46.7% (10 microg/L INH, P < 0.01) or 21.9% - 36.9% (5 microg/L INH, P < 0.01) when compared with corresponding concentration of INH alone. The survival of Mycobacterium tuberculosis in THP-1 cells was decreased significantly when Mycobacterium tuberculosis was pretreated with 5 micromol/L DZ4 plus subinhibitory concentration of INH. 4 or 7 days after infection, the bacteria burden in macrophages was decreased from 126.5 x 10(4) CFU, 307.5 x 10(4) CFU to 54.6 x 10(4) CFU, 114.3 x 10(4) CFU (when 10 microg/L INH used) or from 133.0 x 10(4) CFU, 325.4 x 10(4) CFU to 71.7 x 10(4) CFU, 174.4 x 10(4) CFU (when 5 microg/L INH used). 10-23 DRZ showed no obvious effect on the growth of Mycobacterium tuberculosis in M7H10 agar. CONCLUSIONS: INH at the subinhibitory concentration can improve the entry of 10-23 DRZ in Mycobacterium tuberculosis. In the presence of subinhibitory concentration of INH, 10-23 DRZ targeting ICL gene can strongly inhibit the expression of ICL and decrease the survival of Mycobacterium tuberculosis in macrophages.

Antitubercular Agents↗

PubMed2006

[Relationship of stress index with lung recruitment and gas exchange in dogs with acute respiratory distress syndrome].

OBJECTIVE: To determine the relationship of stress index with lung recruitment and gas exchange in dogs with acute respiratory distress syndrome (ARDS). METHODS: The ARDS model was induced by infusion of oleic acid intravenously in anesthetized dogs. During volume control ventilation with constant inspiratory flow, the pressure-time (P-t) curve was fitted to a power equation: P = a.time(b)+c, where coefficient b (stress index) describes the shape of the curve: b = 1, straight curve; b < 1, progressive increase in slope; and b > 1, progressive decrease in slope. Tidal volume (V(T)) was 6 ml/kg, and positive end-expiratory pressure (PEEP) was set to obtain a b value between 0.9 and 1.1 before (b = 1) and after (b = 1 after recruiting maneuver) application of a recruiting maneuver (RM). PEEP was changed to obtain 0.6 < b < 0.8 and 1.1 < b < 1.3. Experimental condition sequence was random. Recruited volume (RV) was measured by static pressure-volume curve method. Hemodynamics, pulmonary mechanics and gas exchange were observed at the same time. RESULTS: At b = 1 without RM, the PEEP was (5.0 +/- 3.0) cm H2O, the RV was (27 +/- 15) ml, and the RV increased to (166 +/- 84) ml significantly at b = 1 after RM [PEEP (10.8 +/- 2.3) cm H2O (1 cm H2O = 0.098 kPa), q = 3.18, P < 0.01]. At 1.1 < b < 1.3 after RM, the PEEP was (16.8 +/- 1.1) cm H2O and the RV was (262 +/- 57) ml, which was higher than that at b = 1 after RM (q = 2.54, P = 0.023). At 0.6 < b < 0.8 after RM, the PEEP was (5.6 +/- 2.2) cm H2O and the RV was lower than that at b = 1 after RM (q = 2.85, P = 0.013). The partial pressure of oxygen in arterial blood (PaO2) in b = 1, 0.6 < b < 0.8 and 1.1 < b < 1.3 after RM were (319 +/- 49) mm Hg (1 mm Hg = 0.133 kPa), (246 +/- 57) mm Hg and (314 +/- 27) mm Hg respectively, which was higher than the PaO2 at b = 1 without RM [(153 +/- 64) mm Hg, all q = 2.81, all P < 0.05]. The PaO2 at 0.6 < b < 0.8 was lower than that at b = 1 after RM (q = 2.81, P = 0.005), while there was no significant difference between the PaO2 at 1.1 < b < 1.3 and that at b = 1 after RM. The peak airway pressure and plateau pressure at 1.1 < b < 1.3 were higher than those at b = 1 after RM (q = 6.02, 5.72, all P < 0.05). CONCLUSION: In the b = 1 after RM, there were better PaO2 and lower airway pressure, suggesting that b = 1 after RM may be a good indicator for PEEP titration.

Animals↗

PubMed2006

[Experimental study on corneal organ culture preservation and its application].

OBJECTIVE: To develop a optimal method of corneal organ culture preservation, to evaluate the characteristics of organ cultured cornea and to examine the feasibility of application of organ cultured corneas. METHODS: Thirty-six adult New Zealand rabbit corneas were stored in the closed storage system consisting of fetal calf serum and were transferred to a hyperosmosis dextran-containing medium for 48 hours' deswelling for further experiment after storage for 1, 2, 3 and 4 weeks. The measurement of corneal endothelium density and central thickness was performed prior to and after the storage. The morphology and the contamination of preserved cornea, as well as allogenic grafts' conditions within 7 days after corneal transplantation were also observed. The class II MHC antigen immunofluorescence marker was performed for the examination of corneal dendritic cells by confocal microscopy. RESULTS: The corneal organ culture preservation was successfully established. The contamination rate was approximately 8.3%. All of the rabbit corneas stored within 4 weeks remained transparent. There were little folds in peripheral descemet's membrane when the storage time was up to 3 weeks and the whole descemet's membrane folds was seen when the corneas had been preserved for 4 weeks. The density of corneal endothelium decreased when the preservation time was extended. The loss of corneal endothelium preserved up to 4 weeks was 15.7%. Correlation existed between the thickness of center cornea and the preservation time. The average central thickness of the cornea was 0.7 mm after 4 weeks. The light micrographs showed that the endothelium layer still covered the descemet's membrane completely after 4 weeks. The dendritic cells resided in the limbus epithelium and they were lost after stored for 3 weeks. After allogenic corneal transplantation, the grafts retained transparency within 7 days postoperatively, which indicated that there was no primary failure of grafts. CONCLUSION: Corneal organ culture preservation can ensure the normal function of cultured cornea within a certain preservation time and offer some advantages, e.g. the decrease of corneal immunogenicity.

Animals↗