1.The establishment of a modified method to evaluate angiogenesis of rat rings in serum free medium
Chinese Journal of Marine Drugs 1994;0(01):-
The establishment of a modified method to evaluate angiogenesis of rat rings in serum-free medium was investigated in this paper. The aorta rings of Wistar rats were embedded in fibrinogen gel in 48 well plates, and cultured in an optimized serum free medium MCDB131. Results indicated that new capillaries spouted on 4th day, and entered into growth phase from 6th day, and peaked on 13th day and remained unchanged thereafter.
2.The relationship between sulfated polysaccharides and atheroscle rosis
Jinfeng HU ; Meiyu GENG ; Juntian ZHANG
Chinese Pharmacological Bulletin 2001;17(2):127-131
The atherogensis was involved in a complex pathological process. Injury to endothelial cells of blood vessels was confirmed to be the in itial stage of this process. Migration to subendothelial layer and accumulation and proliferation of smooth muscle cells were attributed to various cytokines an d adhesive molecules secreted by activated endothelial cells, subsequently resul ting in aggregation of lymphocytes,platelets, monocytes and macrophages in the i ntima of artery. These cellular components ultimatedly led to the formation of a mature atherosclerotic plaque. Its quite acknowledged that a better understan ding of the atherogenic events might promise us the development of new chemical entities of anti-atherosclerotic therapies. A large body of evidence has demons trated that sulfated polysaccharides played a critical role in the development o f atherosclerosis. The underlying mechanisms of the anti-atherosclerotic activi ty of sulfated polysaccharides were reported to contribute to protecting against endothelial cells injury,inhibiting migration and proliferation of vascular smo oth muscle cells, and reducing the adhesion of inflammatory cells, platelets and lymphocytes. And also, the prevention of complement activation by sulfated poly saccharides could not be excluded. On the other hand,the promoting effects of su lfated polysaccharides atherosclerosis was also reported. Its therefore conclu ded that the relationships between atheriosclerosis and sulfated polysaccharides remained to be further elucidated.
3.Protective effect of alginate polysaccharide JM on brain ischemia injury in rats
Ying FAN ; Zhao YANG ; Meiyu GENG
Chinese Journal of Marine Drugs 1994;0(01):-
Objective To evaluate the effect of alginate polysaccharide JM on rats impaired by brain ischemia,and to elucidate its mechanisms.Methods By using the middle cerebral artery occlusion(MCAO) induced by nylon surgical thread inserted through the internal carotid artery into the anterior cerebral artery in rats,the effects of JM on neurological dysfunction and infarct volumn in rats brain were investigated.Neuroblastoma SH-SY5Y cells were employed to study the inhibitory effects of JM on cytotoxicity induced by hypoxia-hypoglycemia.Results JM at the doses of 12.5 and 25 mg?kg-1,iv,30 min before ischemia impressed neurological dysfunction,characterized by the decreased behavioral obstacle scores of MCAO rats.The infarct volumn declined 24h after ischemia as well.Further investigation by flow cytometry revealed that JM significantly reduces the overloading of intracellular free calcium on and suppresses apoptosis induced by hypoxia-hypoglycemia in human neuroblastoma SH-SY5Y cells.Conclusion JM showed protective effects on brain ischemia,probably related to its inhibitory effect on the overloading of intracellular free calcium ion(\i) and cell apoptosis.
4.Effects of D-Polymannuronic sulfate on potential-dependent and/or receptor-operated calcium channel in rat aortic rings
Haibo ZHU ; Meiyu GENG ; Huashi GUAN
Chinese Journal of Marine Drugs 1994;0(03):-
The effects of D-polymannuronic sulfate (DPS) on the norepinephrine (NA) or potassium chloride (KCL)-induced contraction of rat aortic rings were studied in this paper. The results showed that DPS at the final concentration of Img ? L-1 inhibited the contraction of aortic rings e-voked by NA or KCL and shift doseresponse curves for NA or KCL to the right in a non-parallel fa-sion and depressed their maximal response, implicating that DPS afforded the noncompetitive antagonism on contraction of rat aortic rings induced by NA or KCL. This finding suggested that DPS exerted an inhibitory action of potential-dependent calcium channel and that of receptor-operated calcium channel in vascular smooth muscle.
5.Determination of poly-mannugluronic acid in urine by electrophoresis
Wei XIA ; Gang DENG ; Meiyu GENG ;
Chinese Journal of Marine Drugs 1994;0(01):-
Objective To establish a cellulose acetate membrane electrophoretic method for separating the exogenous sulfated poly mannuguluronicate(911) from glycosaminoglycans.Methods 911 both in urine and ultrafiltrated urine were extracted with cetylpyridinium chloride (CPC), and then separated by two step electrophoretic method with two different buffer solutions. Results The results indicated that 911 was thoroughly separated from endogenous CSC and DS with its average recovery in urine approximately at 70%. Furthermore, the lowest sensitivity for determination of 911 in aquatic solution was 100 ?g?L -1 , whereas that in urine 250 ?g?L -1 and in ultrafiltrated urine 500 ?g?L -1 . And most importantly 911 in rat's urine was detectable after it's oral administration at dose of 200mg?kg -1 . Conclusions It is the first time for us to conduct the existence of 911 in urine by two step electrophoretic method with two different buffer solutions, suggestive of the feasibility to determine 911 in urine even following it's oral administration.
6.The signal transduction and drug development of epithelial-mesenchymal transition
Siyun XU ; Jing LI ; Meiyu GENG
Chinese Pharmacological Bulletin 2003;0(09):-
Epithelial-mesenchymal-transition(EMT) plays a key role in the formation of embryo.At present,it is believed that EMT also contribute to the metastasis of primary tumors.A lot of signaling pathways participate in EMT,such as Wnt/?-catenin,Notch,Hedgehog,TGF? and growth factor receptors.The drugs that affect these pathways may play an important part in oncotherapy.
7.The role of protein kinase C in cancer and the progress of inhibitors targeting protein kinase C
Li LI ; Jing LI ; Meiyu GENG
Chinese Pharmacological Bulletin 1986;0(06):-
Protein Kinase C(PKC) plays a key role in carcinogenesis and metastasis,therefore,PKC is the potential molecular target to develop the treatments of cancer.Currently several PKC inhibitors have entered the clinical research stage,at the same time they also bring new challenges to research and development of anti-cancer drugs targeting PKC.The article will review the recent role of PKC in cancer and the progress of inhibitors targeting PKC.
8.The relationships between senile plaques, neurofibrillary tangles and sulfated polysaccharides
Jinfeng HU ; Meiyu GENG ; Juntian ZHANG ;
Chinese Pharmacological Bulletin 1987;0(01):-
Two aberrant structures, extracellular senile plaques (SP) and intracellular neurofibrillary tangles (NFTs) are the characteristic neuropathological hallmarks of Alzheimers disease (AD). Amyloid ? protein (A?) and hyperphosphorylated tau protein are the major components of SP and NFTs respectively. A large body of evidence has highlighted the pivotal role of sulfated polysaccharides in the amyloidogenesis and formation of NFTs. The underlying mechanisms of the involvement of sulfated polysaccharides in the development of AD were reported to contribute to their high affinity for both A? and tau protein. Sulfated polysaccharides not only promoted the ? secretase cleavage of APP and the increased production of A? and induced the aggregation and deposition of A?, but also facilitated the phosphylation of tau and promoted tau polymerization into fibrils and tangle formation. On the other hand, the neurotrophic effects exerted by sulfated polysaccharides were also demonstrated. These notions were probably due to the inhibition of the formation of A? fibrils or to the counteraction of the abnormal phosphorylation of tau by promoting the protein phosphatase2B activity, which has been speculated to be attributed to the variation in either structural backbone or degree of sulfation or position of sulfation. Putting together, the appropriate structural modification of sulfated polysaccharides may be effective as therapeutic agents for AD.
9.Binding experiments of 911-FITC with Immunocytes
Benchun MIAO ; Meiyu GENG ; Jing LI
Chinese Journal of Marine Drugs 2001;0(05):-
Lymphocytes from thymus, spleen, macrophages and endothelial cells w.ere incubated with the fluorescent probe of 911-FITC and the colouring method with flow cytometry and fluorescent microscope was reviewed in this paper. The results indicated that 911-FITC could specifically bind to lymphocytes, macrophages and endothelial cells. These findings suggested that 911 could play a immunomodulatory effect by direct combination with immu-nocytes.
10.Investigation progress on receptors of saccharides
Benchun MIAO ; Jing LI ; Meiyu GENG
Chinese Pharmacological Bulletin 2003;0(07):-
More and more interest has been put on the investigations of saccharides recent years. Saccharides have a vast number of bioactivities and the immunomodulating effect of saccharides is one of the important mechanisms via which saccharides exert their bioactivities. Saccharides exert their bioactivities mainly by interacting with all kinds of saccharide receptors on cells, followed by a series of signal transduction process. In the present paper, numerous saccharide receptors and the characters of the mutual interaction between saccharides and their receptors are summarized.