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Biomedical subjects

L Li

Publications and source records attributed to L Li.

At least 451 records · Page 25Linked to original sources
PubMed2001

[Effects of para-aminobenzoic acid (PABA) on growth of Lactobacillus acidophilus].

OBJECTIVE: The aim of this study is to examine effects of para-aminobenzoic acid (PABA) on the growth of Lactobacillus acidophilus (L. acidophilus). METHODS: Different concentrations of PABA (10(-10)-10(-3) g/L) were separately transferred to the modified Carlsson medium. L. acidophilus (ATCC4356) grew in these Carlsson media. All cultures were incubated at 37 degrees C anaerobically in atmosphere of 80% of nitrogen, 10% of hydrogen, and 10% of carbon dioxide for 48 hours. Absorbance values (lambda = 540 nm) of bacterial suspensions were measured using a spectrometer (UV-1601). Colony forming units (CFU) were obtained by growing L. acidophilus in Carlsson media with different concentration of PABA (10(-10)-10(-3) g/L). RESULTS: Different concentrations of PABA (10(-10)-10(-4) g/L) had different stimulating effects on the growth of L. acidophilus (P < 0.05). But stimulating effects declined, when PABA concentration was 10(-5) g/L, and when the concentration of PABA reached 10(-3) g/L, the stimulating effect disappeared. CONCLUSION: This study indicates PABA stimulates the growth of L. acidophilus, and PABA can promote growth of L. acidophilus.

4-Aminobenzoic Acid↗
PubMed2001

[IL-1 beta mRNA and TNF-alpha mRNA expression in gingival tissues of patients with adult periodontitis].

OBJECTIVE: The aim of this study was to examine interleukin-1 beta (IL-1 beta) mRNA and tumor necrosis factor alpha (TNF-alpha) mRNA expression in gingival tissues of patients with adult periodontitis. METHODS: A total of 19 patients, including 10 patients with adult periodontitis and 9 healthy individuals as the control, were evaluated for were selected for evaluating IL-1 beta mRNA and TNF-alpha mRNA expression, using reverse transcription polymerase chain reaction (RT-PCR) technique. RESULTS: The relative amount of IL-1 beta mRNA expression of gingival samples from patients with adult periodontitis (0.819 +/- 0.045) (P < 0.01) was much higher than that from the normal control (0.306 +/- 0.087) (P < 0.01). The relative amount of TNF-alpha mRNA expression, gingival samples from AP patients (0.696 +/- 0.098) was also much higher than that from the normal control (0) (P < 0.01). CONCLUSION: As the inflammatory and bone absorption mediators, IL-1 beta and TNF-alpha might play important roles in the pathogenesis and development of adult periodontitis.

Adolescent↗
PubMed2001

[Expression of VEGF-C and its correlation with cervical lymph nodes metastasis of oral cancers].

OBJECTIVE: Vascular endothelial growth factor C (VEGF-C) is known to be capable of inducing cell proliferation of lymphatic endothelia and development of lymphatic vessels. Thus, in the current study the expression of VEGF-C was investigated to understand the mechanism of lymphatic metastasis of oral cancer. METHODS: VEGF-C protein expression in benign and malignant oral lesions was investigated with an immunohistochemical staining assay, followed by light microscopic examination and image analysis. RESULTS: Immunohistostaining of VEGF-C was observed in normal, benign and malignant epithelia, as well as in some lymphatic vessels. The VEGF-C positive rate was significantly higher in squamous carcinomas than in normal tissues and benign lesions. It was also noted that in squamous carcinomas the expression level of VEGF-C correlated well with pathological grades and stages of lymph node metastasis, but not with clinical grades. CONCLUSION: These findings suggest that VEGF-C may promote lymphatic metastasis of oral cancer, and it is possible to be used as a predictor for the lymphatic metastasis and prognosis of oral cancer.

Carcinoma, Squamous Cell↗
PubMed2001

[Preparation of cucurbitacinBE polylactic acid nano-particles for targeting cervical lymph nodes].

OBJECTIVE: Anti-cancer nano-particles for targeting cervical lymph nodes were designed and prepared on the basis of the physiologic and anatomic properties of the peri-oral cancer lymphatic capillaries. METHODS: The biodegradable polylactic acid (PLA) was selected as the carrier material, and cucurbitacinBE (CuBE) with very high anticancer activity against oral squamous cell carcinoma was used as the model drug. According to the criteria of the diameter of the nano-particles, drug loading (DL) and embedding ratio (ER), the preparing technology was optimized by uniformly designing experiment on the basis of single-factor experiment. CucurbitacinBE poly-lactic acid nano-particles (CuBE-PLA-NP) was prepared with the method of emulsion solvent evaporation, and then CuBE-PLA-NP lyophilization injection was prepared by using 10% manninositose as the supporting agent. RESULTS: The diameter distribution for optimized CuBE-PLA-NP lyophilization injection ranged from 47 nm to 120 nm, and the average diameter was 85 nm. DL and ER were 23.03% +/- 0.47% and 93.00% +/- 0.10% respectively. The release study of the thermostatics also demonstrated that Higuchi equation was adequate to fit the release curve of CuBE-PLA-NP. CONCLUSION: CuBE-PLA-NP can be used as the release agent, as CuBE-PLA-NP can enter peri-oral cancer lymphatic capillaries for targeting cervical lymph nodes by the peri-cancer submucosal injection. Therefore, it can also used for animal and clinical experiments.

Antineoplastic Agents↗
PubMed2001

[Acute toxicity and local stimulate test of cucurbitacinBE polylactic acid nano-particles of targeting cervical lymph nodes].

OBJECTIVE: The aim of this experiment was to study acute toxicity and local stimulation of cucurbitacinBE poly-lactic acid nano-particles (CuBE-PLA-NP) for targeting cervical lymph node. METHODS: Various doses of CuBE-PLA-NP lyophilization injection and cucurbitacinBE (CuBE) were hypodermically or veno-injected into the mice, and then the drug toxicity and side effects were observed; 50% lethal dose (LD50) was counted. CuBE-PLA-NP lyophilization injection and CuBE were also injected into the quadriceps femoralis muscle of rabbits to observe the local stimulate responses of drugs. RESULTS: The fifty percent lethal doses of subcutaneous and venous CuBE-PLA-NP in mice were 16.74 mg/kg +/- 1.83 mg/kg and 5.60 mg/kg +/- 0.83 mg/kg respectively, that were higher than those of CuBE which were 8.63 mg/kg +/- 1.00 mg/kg and 2.50 mg/kg +/- 0.30 mg/kg respectively. Local stimulate response in rabbit quadriceps femoralis muscle after CuBE-PLA-NP and CuBE injected are 0 grade and 0.1 grade respectively. CONCLUSION: The acute toxicity of CuBE-PLA-NP is lower than that of CuBE. Both CuBE-PLA-NP and CuBE are adequate for local injection, but the local stimulation of CuBE-PLA-NP is smaller than that of CuBE.

Animals↗
PubMed2001

[Determination of angiotensin-converting enzyme activity by micellar electrokinetic capillary chromatography].

A sensitive and rapid method was developed for angiotensin-converting enzyme (ACE) activity determination by micellar electrokinetic capillary chromatography (MECC). MECC was carried out to separate and quantify the products of the enzymatic reacting using Hip-Leu-His as the substrate in 20 mmol/L boric acid-borate buffer (pH 9.0) including 50 mmol/L SDS as the run buffer at an applied voltage of 8.1 kV. The electrophoresis was monitored at 228 nm, and completed in 6 minutes. The detection limits of ACE activity was 5 pmol/min(signal to noise ratio was 2).

Buffers↗
PubMed2001

[The effect of autocrine factors on development of early embryos of mouse].

Two-cell-stage embryos were flushed from the oviducts on Day 2. Zygotes were collected from oviducts on Day 1 (Fertilization In Situ, ISF) or derived from fertilization in vitro (IVF). 2-cell embryos had a high rate of blastocyst development to each embryo concentration from 1 embryo/microliter to 1 embryo/1000 microliters. The zygotes produced by either ISF or IVF were adversely affected by reducing the embryo concentration over this range (P < 0.001), with approximately 82.5% of ISF zygotes developing to blastocysts at highest concentration but only 22.3% at the lowest. For IVF zygotes the corresponding results were 46.3% and 5.2%. The number of cells in each blastocyst from 2-cell embryos was significantly higher than that from ISF and IVF group. The media supplementing Platelet-activating factor (PAF) caused a significant increase in the rate of blastocyst development of IVF zygotes at embryo concentration of 1 embryo/10 microliters (10 ng/ml) and 1 embryo/100 microliters (100 ng/ml). Insulin-like growth factor (IGF) (10 ng/ml) also stimulated development of IVF zygotes when they were cultured at the concentration of 1 embryo/10 microliters. Epidermal growth factor (EGF) was no effect over range of 1-1000 ng/ml to embryo development. The results show that factors necessary for normal embryo development are diluted to suboptimal levels during culture at low embryo concentration. The PAF, IGF-I partially compensate the effects of low embryo concentration during culture and play important roles as autocrine embryotrophic factors.

Animals↗
PubMed2001

[CEA comprehensive evaluation for Western and traditional Chinese hypotensive drugs].

OBJECTIVE: To make a cost-effectiveness analysis (CEA) comprehensive evaluation for 4 hypotensive drugs, by observing the effects of drugs on blood pressure lowering, symptom improving, and adverse effect and quality of life (QOL) influencing. METHODS: Two hundred and ninety-two patients with mild to moderate hypertension were divided into 4 groups at random and treated with compound Lingjiao Jiangya Pill, benazepril, amlodipine and indapamide respectively with a therapeutic course of 6 weeks. QOL was measured with FS-36 questionnaire and efficacy policy model was applied for comprehensive evaluation of CEA. RESULTS: Through CEA a comprehensive evaluation was made in order as follows: indapamide 3.65 which was the best, and then Lingjiao Jiangya Pill 3.55, amlodipine 2.90 and benazepril 2.35. CONCLUSION: The 4 drugs can not only lower blood pressure but also improve clinical symptoms with less adverse effect. It is of great practical significance to evaluate hypotensive drugs by combining QOL appraisal. The position of Lingjiao Jiangya Pill in CEA order suggests that more attention should be paid to herbal hypotensive drugs.

Adult↗
PubMed2001

[Glucosides from Pleurospermum rivulorum].

AIM: To study the chemical constituents of Pleurospermum rivulorum. METHODS: To separate the constituents of P. rivulorum by using various kinds of chromatography and identify their structures on the basis of spectral analysis. RESULTS: Four glucosides were isolated from P. rivulorum. Their structures were established as marmesinin (I), tert-O-beta-D-glucopyranosyl-heraclenol (II), 1'-O-beta-D-glucopyranosyl (2R, 3S)-3-hydroxynodakenetin (III) and 8-hydroxy-5-O-beta-D-glucopyranosyl-psoralen (IV) based on the analysis of spectral data of IR, UV, MS, 1D and 2D-NMR. CONCLUSION: Compounds III and IV are new compounds. All of the four compounds were isolated from this plant for the first time.

Apiaceae↗
PubMed2001

[Polycystic ovaraian syndrome and hyperinsulinemia].

OBJECTIVE: To identify the relationship between polycystic ovarian syndrome and hyperinsulinemia. METHODS: Age, body height, body weight, serum estradiol, progesterone, testosterone, follicle stimulating hormone (FSH), luteinizing hormone (LH), prolactin (PRL), triiodothyronine (T3), tetraiodothyronine (T4), insulin, oral glucose tolerance test (OGTT), and cortisol were measured in 28 patients with polycystic ovarian syndrome (PCOS). RESULTS: Sxiteen patients (57.1% of total) had hyperinsulinemia. Among them one patient was found diabetic. No difference was noted in age, height, body weight, body mass index, serum estradiol, progesterone, testosterone, FSH, LH, PRL, T3, T4, cortisol, and glucose of OGTT between hyperinsulinemia and non-hyperinsulinemia patients. However the LH/FSH ratio (2.4 +/- 1.5) in hyperinsulinemia patients was significantly higher than 1.2 +/- 0.6 in non-hyperinsulinemia patients (P = 0.0125). In addition, the results showed that the fasting serum insulin, insulin after OGTT, the insulin/glucose ratio at 30, 120 minutes, 180 minutes, the area under curve of and the insulin, insulin resistant index (IRI) were higher in hyperinsulinemia pateints than in non-hyperinsulinemia patients respectively. Furthermore, the fasting insulin level, insulin/glucose ratio were found to be negatively related to insulin sensitivity index and positively related with beta-cell functioning index. CONCLUSION: Hyperinsulinemia and insulin resistance accompany with some of the PCOS patients in China. Further investigations will be necessary to clarify the relevant mechanisms.

Adult↗
PubMed2001

[Investigation on quality difference between Cordyceps of Sichuan and those of Xizang].

OBJECT: The quality difference among the Cordyceps specimens which grew in various micro-ecological environment and between those from Kangding of sichuan and those from Naqu of Xizang was compared and analyzed. METHOD: The specimens from various spots in field were collected, their appearance properties were analyzed, content of adenosine was assayed, and their difference on ecological hereditary variation was discussed. RESULT: The biggest values of quality difference among the Cordyceps specimens from various micro-ecological environment can surpass that between specimen of Sichuan and specimen of Xizang. CONCLUSION: The effect of the micro-ecological environment on the quality of the Cordyceps might exceed that of extensive climates and region differences at times.

Adenosine↗
PubMed2001

[Studies on anamorph of Cordyceps sinensis (Berk) from Naqu Tibet].

OBJECTIVE: To isolate and determine the strain of anamorph of Cordyceps sinensis collected from Naqu Tibet. METHOD: Isolating the strains of anamorph of Cordyceps sinensis collected from Baqing Shuoxian, Biru Counties by means of the ascope, tissue, ossified larva and body liquid. RESULT: Same strain of anamorph of Cordyceps sinensis was obtained with 4 different methods. CONCLUSION: The strain of Hirsutella sinensis is the anamorph of C. sinensis from Naqu Tibet.

Animals↗
PubMed2001

Identification of glucose transporter-1 and it's functional assay in mouse glomerular mesangial cells cultured in vitro.

OBJECTIVE: To evaluate the role of glucose transporter-1 (GLUT1) in the glucose uptake of glomerular mesangial cells. METHODS: Cultured C57/SJL mouse mesangial cells were used in the study. The expression of GLUT1 mRNA was detected by RT-PCR. The expression of GLUT1 protein was detected by immunofluorescence and flow cytometry. The uptake of glucose and its kinetics were determined by 2-deoxy-[3H] -D-glucose uptake. RESULTS: Both GLUT1 mRNA and protein were found in mouse glomerular mesangial cells. 2-deoxy-D-glucose uptake and kinetics assay showed that this glucose transporter had high affinity for glucose and the glucose uptake specificity was further confirmed by phloretin. CONCLUSION: Functional GLUT1 did present in mouse mesangial cells cultured in vitro and it might be the predominant transporter mediated the uptake of glucose into mesangial cells.

Animals↗
PubMed2001

Progress in DNA chip technology.

DNA chip technology employs light-directed in situ oligonucleotide synthesis and/or DNA microarray printing device to produce arrays of large number of probes in the tiny surface of silicon substrates, which makes it possible that the gene detection be conducted efficiently with high speed and sensitivity. The DNA chip may take important part in genome research, gene diagnoses and so on.

Animals↗
PubMed2001

[6A8 alpha-mannosidase catalyzes p-nitrophenyl-alpha-D-mannopyranoside].

OBJECTIVE: To confirm the alpha-mannosidase nature of the protein encoded by 6A8 cDNA. METHODS: 1) To construct a full-length 6A8 cDNA based on the three cloned DNA fragments by means of gene recombinant technique; 2) To insert the 6A8 cDNA into eukaryotic expression vector pCDI; 3) To transfect the recombinant pCDI-6A8 into COS-7 cells; 4) To characterize the nature of the protein encoded by 6A8 cDNA by means of enzymic activity assay and Western blotting assay. RESULTS: The constructed 6A8 cDNA was the right cDNA in sequence. The enzymetic activity of the homogenate of COS-7 cells transfected with pCDI-6A8 was 3-4 times higher than that of the cells transfected with the mock or the wild cells. The enzymetic reaction could not be inhibited by swainsonine. Western blot showed a band of 120,000 recognized by mAb 6A8. The band in the cells transfected with pCDI-6A8 cDNA was much darker than that in the cells transfected with the mock or in the wild cells. CONCLUSION: The protein encoded by 6A8 cDNA is a kind of alpha-mannosidase, which belongs to type II alpha-mannosidase.

Animals↗
PubMed2001

[The role of neuroimmunoregulation mobilized by enhancing immunologic function via hou hai acupoint antigen injection].

OBJECTIVE: To study the mechanism of neuroimmunoregulation which is triggered by enhancing immunologic function via Hou Hai acupoint antigen injection. METHODS: Immunohistochemical method, immunofluorometric method and RT-PCR were used to examine the different distribution of cytokine immunopositive cells in the brain and expression of cytokines in the spleen of the human IgG sensitized rats received acupoint, subcutaneous and normal rats antigen injections. RESULTS: In the areas of lateral hypothalamic nucleus (LH) and amygdaloid nuclear complex (AA), the distribution of cytokines immunopositive cells with acupoint injection group was significantly increased more than that in the subcutaneous injection group. But the expression of cytokines immunopositive cells both by the acupoint injection and the subcutaneous injection groups reached their peak value in similar time. Double-labelling results showed that the cytokine immunopositive cells were neurons. In the spleens, the expressions of cytokines, IL-2 and IFN, were significantly increased by acupoint injection more than subcutaneous injection. CONCLUSIONS: The time course of neuroimmunoregulation is similar in the immunized rats via both acupoint injection and subcutaneous injection of antigens. But the activity of neuroimmunoregulation is not the same in acupoint and subcutaneous injection groups. Neurons of the LH and AA are the main source of the neuroimmunomodulators. The effect of enhancing immunologic function via Hou Hai acupoint injection is may be more efficient to mobilize the activity of neuroimmunoregulation of immune-associated brain region than modulation of the immune system.

Acupuncture Points↗