Biomedical subjects
Publications and source records attributed to Min Chen.
This chapter describes the multiple-shoot-based methods of micropropagation for endangered plant species. Taxus and aloe are used here as examples. For Taxus, the process of micropropagation includes initiating multiple shoots, elongating shoots, rooting shoots, and transplanting plantlets. For aloe, the process of micropropagation includes initiating multiple shoots, rooting shoots, and transplanting plantlets.
Severe acute respiratory syndrome (SARS) first appeared in 2002 in China, which fastly affected about 8000 patients over 29 countries and caused 774 fatalities. As its pathogen was identified as a new kind of coronavirus (SARS_CoV), its genome was quickly sequenced on several isolates. Studies on its functional genomics were performed by combinatorial application of all the available bioinformatics tools and the development of new programs. In this way, it was found that the four proteins were absolutely responsible for nosogenesis of SARS, i.e. spike (S) protein; small envelop (E) protein; membrane (M) protein; and nucleocaspid (N) protein. Molecular evolution studies have revealed that SARS must be originated from wild animals, and it was demonstrated that the major genetic variations in some critical genes, particularly the Spike gene, was essential for the transition from animal-to-human transmission to human-to-human transmission. Theoretical models, either Logistic model or SIR model, were developed to describe the transmission of SARS. The recorded difference of SARS spreading in Beijing and Hong Kong was also reasonably analyzed according to these models. The whole process of fruitful bioinformatics studies, along with other related scientific investigations have set up an unprecedented paradigm for human of how to battle against sudden-breaking and catastrophic epidemics.
Effects of temperature, light, salinity and developmental phases on the accumulation of red pigments in the C(3) halophyte Suaeda salsa were studied, and the physical and chemical characteristics of the red pigments were also analyzed. The results indicate that: these red pigments are insoluble in organic solvents but free in water, the pigments are red-violet and stable under acidic condition while yellow and unstable under alkaline condition, and they absorb the highest value at wavelength near 538 nm, light suppresses their accumulation and enhances their decomposition. These results suggest that these red pigments are betacyanins. Darkness, low temperatures and high salinity enhance betacyanin accumulation in Suaeda salsa, and darkness in the germination phase is one of the most important environmental factors for the betacyanin accumulation.
Based on the calculation of actual yield per unit area in 2002, this paper analyzed the ecological footprint and its composition of each province in China. The results showed that there was a significant difference in the ecological footprint and its composition among different provinces, e. g., cropland changed from 0. 078 hm2 x cap(-1) in Shaanxi to 0.126 hm2 x cap(-1) in Beijing, grazing land changed from 0.020 hm2 x cap(-1) in Jiangxi to 0.372 hm2 x cap(-1) in Xizang, forestland changed from 0.020 hm2 x cap(-1) in Guizhou to 0.209 hm2 x cap(-1) in Beijing, fishery area changed from 0.001 hm2 x cap(-1) in Xizang to 0.011 hm2 x cap(-1) in Shanghai, built-up area changed from 0.013 hm2 x cap(-1) in Guizhou to 0.045 hm2 x cap(-1) in Neimenggu, and fossil energy changed from 0.251 hm2 x cap(-1) in Guangxi to 2.854 hm2 x cap(-1) in Shanxi. The eastern and southern provinces were mostly in a state of ecological deficit, while the western and northern provinces were mostly in a state of ecological remainder. As for the relationships among ecological footprint, economic development and technological progress, great difference existed in different provinces, e. g. , the ecological footprint was about 1 hm2 x cap(-1) in Fujian, Henan, Sichuan, Anhui, Yunnan, Shaanxi and Guizhou, while the GDP per capita changed from 1.35 x 10(4) yuan in Fujian to 0.3 x 10(4) yuan in Guizhou, and the ecological footprint per 1 x 10(4) yuan GDP changed from 0.74 hm2 in Fujian to 3.51 hm2 in Guizhou. Therefore, to resolve the conflicts between the shortage of natural resources and the economic development of China, emphasis should be put on the provinces with big ecological footprint per capita, low GDP per capita, and high ecological footprint per 1 x 10(4) yuan GDP. In these provinces, economic growth mode and industrial structure should be changed, dependence of economy on natural resources should be decreased, use efficiency and economic output of natural resources should be improved, and ecological, resources and economic sustainability should be realized.
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.
OBJECTIVE: To investigate whether Mycobacterium tuberculosis heat shock protein 70 (TB.HSP70) can be used as an adjuvant carrier to stimulate immune response to an accompanying cytotoxic T lymphocytes (CTL) epitope peptide from hepatitis B virus (HBV) core antigen. METHODS: In vitro, peripheral blood mononuclear cells (PBMCs) from chronic hepatitis B volunteers were stimulated with TB.HSP70-CTL fusion protein and TB.HSP70/CTL complex, and then HBV specific CTL activity was assessed. In vivo, the CD4+ T, CD8+ T and natural killer cells (NKs) in the peripheral blood and in spleens of the immunized mice were measured by flow cytometry and the protective HBV specific immune responses of the mice were also evaluated. RESULTS: The results revealed that both of them could induce HBV specific CTL response in human PBMCs and in the immunized mice. In the mice they activated CD4+ T, CD8+ T and NKs. Furthermore, the immunocompetence of the TB.HSP70-CTL fusion protein was stronger than that of TB.HSP70/CTL complex. The HBV specific killing rate was 28.9%, the CD8+ T cell population was 43.9% and the NKs was 13.6% in splenocytes of immunized mice with TB.HSP70-CTL fusion protein. The CTL peptide alone was capable of generating weak CTL lysis. The TB.HSP70 showed almost no target cell killing. CONCLUSION: The results demonstrate that TB.HSP70 may be used as a new adjuvant carrier to improve the immunogenicity of short CTL epitope and produce effective CTL response.
OBJECTIVES: To investigate the cure effect of tumor antigen specific CTL on a model of human hepatocellular carcinoma in nude mice LCI-D20. METHODS: Dendritic cells (DCs) were induced from peripheral blood mononuclear cells of healthy people in vitro by using recombinant human granulocyte-macrophage colony stimulating factor (rhGM-CSF) and interleukin-4 (rhIL-4) and were pulsed with tumor antigen from hepatocellular carcinoma cell line MHCC97H. Then tumor antigen specific cytotoxic T lymphocytes (CTLs) were induced. By intraperitoneal injection of tumour antigen specific CTLs into the LCI-D20, the preventive and therapeutic effects of these CTLs to HCC in the LCI-D20 model were assessed. Cytokine-induced killer (CIK) cells and phosphate buffer solution were used as controls at the same time. RESULTS: The weights of tumors in the tumor antigen specific CTL group, in the CIK cell group and in the blank group were (1.11+/-0.63), (1.12+/-0.36) and (2.68+/-0.53) grams respectively (t = 5.18, t = 6.06, P < 0.01). The amount of blood alpha fetal protein in the tumor antigen specific CTL and CIK groups were (52.1+/-9.7) microg/L and (48.6+/-5.2) microg/L, and was (82.2+/-7.2) microg/L in the blank group (t = 17.26, t = 22.07, P < 0.01 respectively). The metastasis rates in livers were 16.7%, 16.7% and 58.3% in the tumor antigen specific CTL, CIK cell and blank control groups respectively (chi2= 4.44, P < 0.01). The survival time of the mice in the tumor antigen specific CTL group was (79.0+/-5.02) days, (73.3+/-7.0) days in the CIK group, and (52.3+/-5.2) days in the blank group (t = 14.56, t = 17.54, P < 0.01). CONCLUSION: Tumor antigen specific CTLs may prevent metastasis in the LCI-D20 model and prolong the survival time.
OBJECTIVES: To investigate immune responses and the anti-tumor effect of a constructed Chimeric AFP-Mt.HSP70 DNA vaccine in mice. METHODS: Chimeric AFP-Mt.HSP70 was constructed by molecular clone techniques. Spleen cells derived from mice immunized twice were induced to secrete IFN gamma and were assayed using ELISA. The activity of the cytotoxic lymphocytes (CTL) derived from spleen cells was assayed using lactate dehydrogenase (LDH). 4 x 10(6) Hepa1-6 cells/200 microl were injected subcutaneously into the right axilla of each mouse bearing the tumor. The anti-tumor effect of the recombinant DNA vaccine was evaluated by measuring tumor sizes of the mice. RESULTS: AFP-specific CTL reaction was induced by our chimeric DNA vaccine and Mt.HSP70 enhanced this effect (P < 0.05). The CTL activity was about 32% at E/T=50:1. The IFN gamma secreted by spleen cells of mice immunized with chimeric plasmids was about 200 pg/ml. It was higher than those in the other groups; Tumor sizes of mice immunized with fused plasmids were smaller than those in the other groups. Survival times of mice immunized with the fused plasmids were prolonged. CONCLUSION: Chimeric DNA vaccine can induce AFP-specific CTL reaction and has an anti-tumor effect on transplanted tumors in our murine experiment.
AIM: To investigate the specific humoral and cellular immune response induced by prime-boost immunization of HBsAg protein vaccine (P), recombinant vaccinia virus vaccine (V) and DNA vaccine (D) in mice. METHODS: Groups of BALB/c mice were primed by one of the three vaccines P, V or D and boosted by another vaccine at 2, 5, 8 and 11 week later, thus 9 immune combinations were made: PP, PV, PD, VP, VV, VD, DP, DV and DD. Serum samples were collected at week 2, 5, 8 and 11 and levels of anti-HBsAg IgG antibodies and their sub-isotypes were determined. Seven days after every boost, spleen cells of vaccinated mice were separated and the specific CTL lysis ratio of P815S cells were determined. RESULTS: Among the three HBsAg vaccines P, V and D, V could induce the quickest humoral immune response. The memory humoral immune response induced by P was the strongest. D induced the weakest antibody titer. The ratio of specific IgG1/IgG2a indicated that antibody induced by PP was more polarized to Th2. The other groups induced balanced Th1/Th2 immune response. Among all the groups, VD and DV induced the strongest CTL response, and the specific lysis ratio of P815S cells was 71% and 64%, respectively. CONCLUSION: The experimental results suggested that among all the immune combinations, PV, PD, VP and VD can induce better humoral immune response while DV and VD can induce stronger CTL response in BALB/c mice.
A-kinase can inhibit RhoA activation through phosphorylating ser188 of RhoA. AKAP is a novel protein that can target PKA to different subcellular compartment. Evidence has been presented that PKA anchorage by AKAP is important for the kinase to exert its function. This study analyzed the role of PKA anchorage in PKA-induced antagonism against RhoA activity and function. The cells transfected with pcDNA HT31wt/mut were treated with LPA and/or CPT-cAMP. The amount of GTP-RhoA and phosphorylation of RhoA was detected by Western blotting with specific antibodies. The formation of stress fiber was visualized under fluorescent microscope. The gene expression activity was analyzed by luciferase reporter gene assay. The motility and the anchorage-independent growth assays were carried out with stably transfected cells expressing the AKAP inhibitory peptide HT31. The results showed that HT31 not only blocked the PKA-induced phosphorylation of RhoA but also prevented the PKA-induced inhibition on RhoA activation. The disruption of PKA anchorage abolished its inhibition on the LPA-induced expression of reporter gene SRE-luciferase. The ability of PKA to antagonize the LPA-induced stress fiber formation was partly impaired upon the disruption of the PKA anchorage. The control of PKA on migration and the proliferation excited by LPA disappeared in stably transfected cells highly expressing HT31. The results revealed that PKA anchorage was necessary for the kinase to exert its inhibitory effect on RhoA activation and RhoA-dependent biological activities.
OBJECTIVE: To determine the genetic diversity of natural and cultivated Cistanche tubulosa. METHOD: 123 individuals of six populations of C. tubulosa, including four natural populations and two cultivated ones, were analyzed by random amplified polymorphic DNA (RAPD) markers to determine the genetic variations among the populations. RESULT: A total of 87 loci (including 24 polymorphic loci) were amplified using 10 random primers. The average percentage of polymorphic loci (PPL) was 27.59 in the natural populations. The PPL between natural populations are 19.54 to 25.29. Of the four natural populations, Andi' er population had highest PPL (25.29). The two cultivated populations had low PPL (13.79 and 11.49). Cluster analysis using UPGMA revealed that populations of natural and cultivated were separated into two groups, the four natural populations clustered as one group and the two cultivated populations clustered as another group, indicating that the natural and cultivated populations had obvious differentiation. CONCLUSION: In view of the low genetic diversity of the cultivated C. tubulosa, we strongly suggested that the natural populations should be conserved in particular.
Oxidative and nitrosative stress play an important role in the development of endothelial vascular dysfunction during early atherosclerosis. Oxidative stress activates the nuclear enzyme poly(ADP-ribose) polymerase (PARP) in endothelial cells. In patients with atherosclerosis the level of oxidized LDL in the plasma is elevated. In oxidized LDL various oxysterols have been identified, such as 7-ketocholesterol (7K). 7K has been shown to induce PARP activation in microglial cells. The aim of the current study was to clarify the effects of 7K on the activity of endothelial PARP and on the endothelium-dependent relaxant function of blood vessels. We treated human umbilical vein endothelial (HUVEC) cells with 2-16 microg/ml 7K as well as vascular rings harvested from BALB/c mouse thoracic aorta with 90 microg/ml 7K for 2 h. A group of mice was treated with 7K subcutaneously for 1 week (10 mg/kg/day). We also conducted in vitro and in vivo experiments using pretreatment with buthionine sulphoximine (BSO), a glutathione-lowering agent. The activity of PARP was calculated by measurement of tritiated NAD incorporation. The activity of PARP increased significantly in 7K-treated HUVEC cells. After BSO pretreatment, this increase was higher. Isolated vascular rings demonstrated no change in endothelium-dependent relaxant function after 2 h of incubation with 7K, even after BSO pretreatment. In vivo treatment with 7K for 1 week had no effect on the relaxant function. Our experimental results suggest that although 7-ketocholesterol can activate PARP enzyme in endothelial cells, it is not sufficient on its own to cause impairment in the endothelium-dependent vascular reactivity.
OBJECTIVE: To observe clinical therapeutic effect and safety of combination of acupuncture with medication for treatment of spontaneous tremor. METHODS: With randomized controlled trial method, 26 cases of spontaneous tremor were divided into a treatment group (n = 13) treated with acupuncture plus western medicine, and a control group (n = 13) treated with simple western medicine. They were treated for 6 weeks. Scores of tremor before and after treatment and adverse effects were investigated. RESULTS: The total effective rate of 84.6% in the treatment group was better than 61.5% in the control group (P < 0.05) and there was less adverse effects in the treatment group. CONCLUSION: Combination of acupuncture with medication is a safe and effective therapy for spontaneous tremor.
A method was established for the determination of carotenoids (lutein, zeaxanthin, lycopene, beta-carotene) in health products by reversed-phase high performance liquid chromatography (RP-HPLC). The extraction methods of carotenoids from different types of samples were also established. Separation and quantification was achieved by using a Diamonsil C18 column (250 mm x 4.6 mm i.d., 5 microm), and a mobile phase of acetonitrile and ethyl acetate were used with the following gradient elution: 100% acetonitrile at the first 15 min, then ethyl acetate increased to 100% in the next 10 min, at last 100% acetonitrile for 5 min with a flow rate of 1 mL/min, temperature of 25 degrees C and monitored with a photodiode array detector at 450 nm. The external standard calibration curves were used for quantification. There were good linear correlations for the four carotenoids. The correlation coefficients were between 0.999 4 and 0. 999 7. The detection limits were 0.4-0.5 mg/L. The recoveries of four carotenoids in tablet samples were 95.3%-98.7% with the relative standard deviations (RSDs) of 0.89%-2.0%. The recoveries of four carotenoids in powder samples were 93.7%-98.8% with RSDs of 0.89%-2.8%. The recoveries of four carotenoids in oil samples were 97.1%-99.2% with RSDs of 0.42%-1.2%. This method is simple, fast, accurate and convenient. It can be used as one of the reliable means for quantitative determination of carotenoid in health products.
OBJECTIVE: To determine the genetic diversity of Eucommia ulmoides. METHOD: 260 samples of 20 populations were analyzed through radom amplified polymorphic DHA (RAPD). RESULT: Total polymorphic loci percentage was 96.36 and the average was 38.92. 110 bands were produced with 10 random primers and 106 were polymorphic. Nei's gene diversity (H) was 0.246 1, Shannon's Information index(I) was 0.386 8, Gst was 0.424 4, indicating that 42.44% of the genetic variation was distributed among populations and 57.65% within populations. CONCLUSION: The genetic variation was relatively high in E. ulmoides, so the genetic diversity conservation principle should mainly focus on protection of the populations.
OBJECTIVE: To study human vestibular cerebral representations by combining right-sided ice-water stimulation at 0 degree C with blood oxygenation level dependent functional magnetic resonance imaging (BOLD-fMRI) and to evaluate the value of this method in the functional localization of human vestibular cortex. METHODS: Twenty right-handed volunteers (12 men and 8 women) received unilateral irrigation of the right external auditory meatu for 15 s with 15 ml of water at 0 degrees C during fMRI in complete darkness. The functional imaging of brain cortex was acquired with a 1.5-T MRI scanner (Signa Infinity Twin + Excite; General Electric Co., USA). The successive functional images from each subject were analyzed as a group with statistical parametric mapping software (SPM 99). RESULTS: Ultimately, data obtained from 17 subjects were analyzed (3 subjects were eliminated from data because of head movement exceeding 2 mm). The group analysis showed bilateral (particularly left-sided) cortical activation, associated with caloric stimulus involving in temporoparietal junction extending into the posterior insula, supramarginal gyrus in the inferior parietal lobe, precuneus, supplementary motor area (SMA), the ventrolateral portion of the occipital lobe, cuneus and lingual gyrus, superior temporal gyrus and cingular cortex. CONCLUSIONS: Ice-water stimulation at 0 degree C in fMRI reveals a widespread cortical network involved in vestibular signal processing in human. As the functional localization of vestibular cortex could be determined precisely, ice-water stimulation at 0 degree C in fMRI would hold great promise as a sensitive and reproducible tool for the research in human vestibular cortex.
OBJECTIVE: To elucidate the difference in the pathogenesis between strabismic amblyopia and anisometropic amblyopia. METHODS: Using an EPI gradient echo sequence in 1.5 T MRI and visual electrophysiological system, the pattern visual evoked potentials and calcarine activation by monocular viewing of check-board pattern with reversal were examined in 18 strabismic amblyopes and 15 anisometropic amblyopes. The calcarine activation in terms of binocular voxels index and dependence on the spatial frequency of the stimuli were compared. The correlation between PVEP P(100) latency and activation intensity was also analyzed. RESULTS: The binocular voxels index was lower in the strabismic amblyope than that in the anisometropic amblyope. The calcarine activation from amblyopic eyes in strabismic amblyopes was more suppressed at higher spatial frequencies (1, 2 c/d); while that from amblyopic eyes in anisometropic amblyopes was more suppressed at all spatial frequencies (0.25, 0.5, 1 and 2 c/d). Inverse correlations existed between PVEP P(100) latency and activation intensity in two types amblyopia (P < 0.05). CONCLUSIONS: The binocular interaction is not equal in these two different types of amblyopia. Meanwhile, the amblyopia-related deficits in the low and high-spatial-frequency pathway of visual system are not similar between these two different types of amblyopia.
Sertoli cells play a key role in triggering and regulating the process of spermatogenesis. Failure of a Sertoli cell to mature functionally will presumably render it incapable of supporting germ cell survival and development that appeared after puberty. Expression of cytokeratin 18 (ck-18) intermediate filaments indicates a state of undifferentiation usually observed in Sertoli cells of prepubertal testis. In this study we demonstrated that local testicular heat treatment of adult monkey with water at 43 C for 30 min once daily for 2 consecutive days was capable of activating reexpression of ck-18 in Sertoli cells, which was coincident with activation of ERK1/2 and Akt kinases. Using primary Sertoli cell culture isolated from adult monkey testis, we further confirmed that the heat treatment of the cells at 43 C could also induce ck-18 reexpression, which was similar to the in vivo treatment. ERK MAPK was also induced by the heat treatment in a time- and protein kinase A (PKA)-dependent manner. After blocking the ERK MAPK signaling pathway, an inhibition of ck-18 expression in the cultured Sertoli cells was observed, and this inhibitory effect was also detected by blocking the PKA activation. However, ck-18 activation in Sertoli cells remained unaltered when the phosphatidylinositol 3-kinase/Akt pathway was blocked. In conclusion, the heat treatment of adult monkey Sertoli cells are capable of inducing a reversible change in the Sertoli cells from an adult differentiated state to an immature-like dedifferentiated state through PKA-ERK MAPK-dependent pathways but not via the phosphatidylinositol 3-kinase/Akt pathway.