Biomedical subjects

Min Jia

Publications and source records attributed to Min Jia.

14 recordsLinked to original sources

PubMed2006

Immunomodulatory activity of polysaccharide isolated from Angelica sinensis.

The immunomodulatory activities of an Angelica sinensis polysaccharide (AP), purified from the fresh root of A. sinensis Diels, were investigated in vitro in relation to the specificity to immune cells. AP consisted of rhamnose, arabinose, mannose, glucose, galactose with the molar ratio of 1.00:4.54:2.98:11.09:7.45. Cell proliferation results showed that proliferation of total spleen cells, macrophages and T cells were promoted by the action of AP. The treatment of AP increased the production of IL-2 and IFN-gamma, while that of IL-4 was decreased. RT-PCR analysis displayed that the IL-2 and IFN-gamma gene expression were enhanced but the IL-4 gene expression was decreased. Some differences in cytokines secretion pattern were also detected, the expression of IFN-gamma was rapidly augmented while that of IL-2 responded later. The flow cytometry results showed that the percentage of CD4(+)T cell in total spleen cells was remarkably increased by AP, while that of CD8(+)T cell was slightly decreased. In conclusion, AP has immunomodulatory activity by regulating expression of Th1 and Th2 related cytokines. The time-effect relation of cytokines response also suggests that macrophages and natural killer cells involved in nonspecific immunity were primary activated, and helper T cell were secondarily affected by AP.

Angelica sinensis↗

PubMed2006

Restoration of oxacillin susceptibility in methicillin-resistant Staphylococcus aureus by blocking the MecR1-mediated signaling pathway.

The signal transducing integral membrane protein, MecR1 helps initiate the expression of the antibiotic-resistant gene mecA, which encodes the penicillin-binding protein 2a. MecA participates in the beta-lactam resistance of methicillin-resistant Staphylococcus aureus (MRSA). Blocking the MecR1 regulatory pathway may be a novel strategy to combat MRSA. In this study, we introduced an antisense phosphothioate oligodeoxynucleotide (PS-ODN) targeting MecR1 mRNA into the MRSA strain WHO-2, which led to a significant reduction of both MecR1 and PBP2a mRNAs in a concentration-dependent manner. Consequently, the susceptibility of S. aureus WHO-2 to the beta-lactam antibiotic oxacillin was restored significantly. Our results indicate that blocking the mecR1-mecI-mecA signaling pathway via an antisense approach might be a viable strategy to restore the susceptibility of MRSA to the existing beta-lactam antibiotics.

Analysis of Variance↗

PubMed2006

[Effect of Angelica sinensis polysaccharide fraction AP-3 on IL-2 and IFN-gamma induction].

AIM: To investigate the effects of Angelica sinensis polysaccharide fraction AP-3 on IL-2 and IFN-gamma induction and its further immunomodulatory feature. METHODS: The percentage of CD4+ lymphocyte was detected by flow cytometric method, the production of IL-2 and IFN-gamma in cell culture supernatant were determined by ELISA, mRNA expressions of IL-2 and IFN-gamma cytokines were detected by RT-PCR. RESULTS: At the range of 0. 6 - 2 micromol x L(-1), AP-3 significantly enhanced the percentage of CD4+ lymphocytes in total splenocytes. At the range of 2 - 6 micromol x L(-1), the treatment of AP-3 augmented both productions of IL-2 in cell culture supernatant and cell IL-2 mRNA transcription level in a time and dose dependent manner. While in the case of IFN-gamma, AP-3 stimulated at early time after exposure but down-regulated thereafter. CONCLUSION: Angelica sinensis polysaccharide could regulate the immune response through upregulating IL-2, IFN-gamma expression and activating Th1 cell.

Angelica sinensis↗

PubMed2005

[Effect of Angelica sinensis polysaccharide on lymphocyte proliferation and cytokine induction].

OBJECTIVE: To investigate the effects of Angelica sinensis polysaccharide (AP) and its three fractions (AP-1, AP-2 and AP-3) on lymphocyte proliferation induction of IL-2 and IFN-gamma. METHODS: Effects of AP on proliferation of murine splenocyte, macrophage, mixed lymphocyte reaction were tested by MTT assay. The production of IL-2 and IFN-gamma in supernatant were determined by ELISA. RESULTS: At the range of 30 - 300 microg/ml, AP and its three fractions directly stimulated proliferation of murine splenocyte; AP-3 significantly enhanced the proliferation of macrophage and mixed lymphocyte, the treatment of AP-3 augmented the production of IL-2 and IFN-gamma in cell culture supernatant. CONCLUSION: AP could active macrophage and T lymphocyte, also regulate the immune response through upregulating IL-2, IFN-gamma expression.

Angelica sinensis↗

PubMed2005

[Effects of Angelica sinensis polysaccharide on cell-mediated immunity].

AIM: To investigate the effects of Angelica sinensis polysaccharide (AP) on cell-mediated immunity. METHODS: The lymphocyte proliferation was tested by MTT colormetry; T lymphocyte fraction were separated with immune magnetic beads and the change of CD4(+) T lymphocyte percentage was detected by flow cytometry. RESULTS: In the range of 30-300 mg/L, the total AP and its three fractions, ie AP-0, AP-1, AP-2, AP-3, directly stimulated the proliferation of murine splenocytes, and AP-3 significantly enhanced the proliferation of lymphocytes in MLR and T lymphocytes. The percentage of CD4(+) T lymphocytes in total splenocytes was also enhanced by AP-3. CONCLUSION: AP can promote the cell-mediated immunity with T lymphocytes as one of its target cells.

Adjuvants, Immunologic↗

PubMed2004

The role of the theta isoform of protein kinase C (PKC) in activity-dependent synapse elimination: evidence from the PKC theta knock-out mouse in vivo and in vitro.

PKC plays a critical role in competitive activity-dependent synapse modification at the neuromuscular synapse in vitro and in vivo. This action involves a reduction of the strength of inactive inputs to muscle cells that are activated by other inputs. A decrease of postsynaptic responsiveness and a loss of postsynaptic acetyl choline receptors account for the heterosynaptic loss in vitro. The loss is not seen in preparations in which PKC has been blocked pharmacologically. Here, we show that the loss does not occur in in vitro preparations made from animals genetically modified to lack the theta isoform of PKC. Synapse elimination in the newborn period in vivo is delayed but is eventually expressed in knock-out animals. PKC-dependent synapse reduction is suppressed in heterologous cultures combining normal nerve and PKC theta-deficient muscle, as might be expected from the postsynaptic locus of the changes that underlie the activity-dependent plasticity. Preparations in which PKC theta-deficient neurons innervated normal muscle also exhibited a marked deficit in PKC-deficient synapse reduction. The presynaptic action of PKC theta implied by this observation is blocked by TTX, and we propose that activity-related synapse strengthening is decreased by presynaptic PKC theta. Thus, PKC theta in both presynaptic and postsynaptic elements plays a critical role in activity-dependent synapse modulation and loss. We provide a model for activity-dependent synapse loss incorporating these findings.

Animals↗

PubMed2004

PC-407 inhibited proliferation and induced apoptosis in human colon cancer SW-1116 cells.

AIM: To study whether PC-407 [4-[5-naphthyl-3- (trifluoromethyl)-1H-pyrazol-1-yl] benzenesulfonamide] inhibits cell viability and induces apoptosis in human colon cancer SW-1116 cells. METHODS: Inhibition of SW-1116 proliferation was measured by MTT assay. Morphological assessment of apoptosis was performed with fluorescence microscope and electron microscope. DNA fragmentation was visualized by agarose gel electrophoresis. The amount of apoptotic cells was measured by flow cytometry. RESULTS: PC-407 inhibited SW-1116 cell proliferation in a concentration-dependent manner after 3 d of treatment, and the IC(50) for PC-407 inhibition of cell number was 16.67+/-0.17 micromol/L. After incubation of SW-1116 cells with PC-407 20 micromol/L for 24 h, morphological changes of typical apoptosis were observed by AO/EB staining or transmission electron microscopy. Flow cytometry analysis showed that PC-407 induced apoptosis in SW-1116 cells in a time- and concentration-dependent manner. The agarose gel electrophoresis of DNA revealed a ladder pattern 48 h later. CONCLUSION: PC-407 inhibited proliferation and induced apoptosis in the human colon cancer SW-1116 cell line.

Antineoplastic Agents↗

PubMed2003

Protein kinases and Hebbian function.

The Hebb synapse, in which the strength of synapses is affected by activity in presynaptic and postsynaptic nerve cells, is a widely used model for developmental and learning-related neuroplasticity. Presynaptic and postsynaptic firing that is correlated in time is postulated to increase synaptic strength while activity in presynaptic and postsynaptic neurons that is not correlated results in weakening. The authors describe a cell biologic, mechanistic model for activity-dependent modification of synapse strength that selectively weakens inactive inputs to activated targets. Differentially localized protein kinase A and protein kinase C molecules are activated by spike and synaptic activity. Subsequent kinase-specific phosphorylation and stabilization or destabilization of synaptic receptors are molecular and cell biologic substrates of the Hebb synapse.

Animals↗

PubMed2003

Experimental study of anti-tumor effects of polysaccharides from Angelica sinensis.

AIM: To investigate the in vivo anti-tumor effects of total polysaccharide (AP-0) isolated from Angelica sinensis (Oliv.) Diels (Danggui) on mice and the in vitro inhibitory effects of AP-0 and the sub-constituents (AP-1, AP-2 and AP-3) separated from AP-0 on invasion and metastasis of human hepatocellular carcinoma. METHODS: Three kinds of murine tumor models in vivo, sarcoma 180 (S180), leukemia L1210 and Ehrlich ascitic cancer (EAC) were employed to investigate the anti-tumor effects of AP-0. For each kind of tumor model, three experimental groups were respectively given AP-0 at doses of 30, 100 and 300 mg/kg by ip once a day for 10 days. Positive control groups were respectively given Cy at a dose of 30 mg/kg for S180 and leukemia L1210, and 5-FU at a dose of 20 mg/kg for EAC. On d 11, mice bearing S180 were sacrificed and the masses of tumors, spleens and thymus weighed. The average living days of mice bearing EAC and of mice bearing L1210 were observed, and the rates of life prolongation of each treatment were calculated, respectively. The inhibitory effects of APs on hepatoma invasion and metastasis in vitro were investigated by employing human hepatocellular carcinoma cell line (HHCC) with the Matrigel invasion chamber, adhesion to extracellular matrix and chemotatic migration tests, respectively. RESULTS: AP-0 had no obviously inhibitory effect on the growth of S180, but it could significantly decrease the thymus weights of the mice bearing S180. AP-0 could significantly reduce the production of ascitic liquids and prolong the life of mice bearing EAC. AP-0 could also increase the survival time of mice bearing L1210. AP-0 and AP-2 had significantly inhibitory effects on the invasion of HHCC into the Matrigel reconstituted basement membrane with the inhibitory rates of 56.4 % and 68.3 %, respectively. AP-0, AP-1, AP-2 and AP-3 could influence the adhesion of HHCC to extracellular matrix proteins (Matrigel and fibronectin) at different degrees, among them only AP-3 had significant blocking effect on the adhesion of HHCC to fibronectin with an inhibitory rate of 30.3 %. AP-0, AP-1 and AP-3 could partially inhibit the chemotactic migration abilities of HHCC. CONCLUSION: The experimental findings suggest that the total polysaccharide of Angelica sinensis (Oliv.) Diels (Chinese Danggui) possesses anti-tumor effects on experimental tumor models in vivo and inhibitory effects on invasion and metastasis of hepatocellular carcinoma cells in vitro.

Angelica sinensis↗

PubMed2003

[Effect of noninvasive positive pressure ventilation on treatment of acute respiratory distress syndrome].

OBJECTIVE: To investigate the factors affecting the effect of noninvasive positive pressure ventilation (NIPPV) on treatment of acute respiratory distress syndrome (ARDS). METHODS: According to the disease-induced factors, patients with ARDS were divided into two groups: group A (pulmonary factors), group B (extra-pulmonary factors). Different kinds of ventilator s were used in the course of NIPPV via facial or nasal mask. The mode, biphasic intermittent positive airway pressure (BiPAP, BiPAP vision), pressure support ventilation (PSV) + positive end-expiratory pressure (PEEP) or synchronized intermittent mandatory ventilation (SIMV) + PSV + PEEP, was administered. After 3-10 hours, the patients who were not fit to NIPPV were conducted intubation. RESULTS: Group A had 9 cases, of whom 5 cases were treated with NIPPV all the time, while in group B, 14 cases, of whom 12 cases The cure rate of group A by NIPPV was 55.6% (5/9), while that of group B was 85.7% (12/14), P<0.05. CONCLUSION: Selecting proper indication, reasonable ventilator mode and parameters, and improving the unfavorable factors can contribute to the decrease of intubation rate.

Adult↗

PubMed2002

Pre- and postsynaptic mechanisms in Hebbian activity-dependent synapse modification.

We have used a three compartment tissue culture system that involved two separate populations of cholinergic neurons in the side compartments that converged on a common target population of myotubes in the center compartment. Activation of the axons from one population of neurons produced selective down-regulation of the synaptic inputs from the other neuronal population (when the two inputs innervated the same myotubes). The decrease in heterosynaptic inputs was mediated by protein kinase C (PKC). An activity-dependent action of protein kinase A (PKA) was associated with the stimulated input and this served to selectively stabilize this input. These changes associated with PKA and PKC activation were mediated by alterations in the number of acetylcholine receptors at the neuromuscular junction. These results suggest that neuromuscular electrical activity produces postsynaptic activation of both PKA and PKC, with the latter producing generalized synapse weakening and the former a selective synapse stabilization. Treatment of the neuronal cell body and axon to increase PKC activity by putting phorbal ester (PMA) in the side chamber did not affect synaptic transmission (with or without stimulation). By contrast, PKA blockade in the side compartment did produce an activity-dependent decrease in synaptic efficacy, which was due to a decrease in quantal release of neurotransmitter. Thus, when the synapse is activated, it appears that presynaptic PKA action is necessary to maintain transmitter output.

Animals↗

PubMed2002

Capillary electrophoretic enzyme immunoassay with electrochemical detection for cortisol.

A novel capillary electrophoretic enzyme immunoassay with electrochemical detection has been developed and used for the determination of cortisol. In this method, after the competitive enzyme immunoreaction, the free enzyme (horseradish peroxidase, HRP)-labeled cortisol (HRP-cortisol) and the bound enzyme-labeled cortisol (HPR-cortisol-anti-cortisol) were separated in the separation capillary and then catalyzed the enzyme substrate [3,3,5,5-tetramethyl-benzidine dihydrochloride, TMB(Red)] in the reaction capillary. The product of the enzymatic catalysis reaction [TMB(Ox)] was amperometrically detected on a carbon fiber microdisk bundle electrode. A concentration limit of detection (LOD) of 1.7 x 10(-1) mol/l, which corresponds to a mass LOD of 7.8 amol, was achieved with the relative standard deviation of 3.3%. The method has been verified using the cortisol controls.

Electrochemistry↗

PubMed2002

[Effects of Angelica polysaccharide on blood coagulation and platelet aggregation].

OBJECTIVE: To investigate the effects of angelica polysaccharide (AP) on blood coagulation and platelet aggregation. METHODS: Infrared turbidimetric method was used to estimate platelet aggregation, active partial thromboplastin time (APTT), prothrombin time (PT) and thrombin time (TT); bleeding time (BT) was measured by cutting the mouse's tail and coagulate time (CT) was measured by dropping the blood on carry sheet glass. RESULTS: AP prominently enhanced the platelet aggregation at 5 min, while showed less effects on the maximum platelet aggregation. It also markedly prolonged CT but shortened BT. AP significantly prolonged TT and APTT in dosage of 3 mg/kg and 10 mg/kg, while showed no obvious effect on PT. CONCLUSION: These results suggest that AP has potent anticoagulant and haemostasis effects. The haemostasis effect is related to promoting platelet aggregation.

Angelica sinensis↗

PubMedDate not supplied

Phosphorylation reactions in activity-dependent synapse modification at the neuromuscular junction during development.

We have studied developmental activity-dependent synapse diminution in both an in vitro tissue culture chamber system and at the intact rodent neuromuscular junction (nmj). In both types of preparations, pre- and postsynaptic alterations in synapse structure and function are produced by manipulations of thrombin (Thr) and protein kinase C (PKC) activity. An opposing postsynaptic effect of PKC and protein kinase A (PKA) action on the acetycholine receptor (AChR) can be shown in vitro with PKA stabilizing and PKC destabilizing the nmj synapses. In vivo studies of normal junctional maturation show that changes in axonal inputs and postsynaptic receptor cluster morphology occur, to a substantial degree, independently of one another. Presynaptic actions of PKA are involved in the activity dependent synapse modulation that can be demonstrated in vitro. Late in the elimination process, (>12 days in vivo ) the process becomes independent of PKC, implying that diverse, redundant mechanisms are involved in this important developmental process.

Action Potentials↗