Sialic acids (neuraminic acids) are a special series of 9 carbon ring negatively charged carbohydrates, which has been found to be selectively changed in malignant cells from structures (both synthesis and structure ...Sialic acids (neuraminic acids) are a special series of 9 carbon ring negatively charged carbohydrates, which has been found to be selectively changed in malignant cells from structures (both synthesis and structure modifications) to functions (up and down regulation in cells). Sialic acids, in single forms or conjugates, have been systematically studied both in lab and in clinics by GC, GC MS, NMR, HPTLC, HPLC and other modern analytical means. Sialic acids and related conjugates are predicted to be used in cancer diagnosis, cancer prognostic forecasting, designing of cancer chemotherapy regimens, uncovering carcinogenetic processes and neoplasm metastasis. Tumor cell regulative systems and pathways are correlated with sialic acids, which can be applied to prognostic evaluation of cancer patients, and antimetastatic chemotherapy by sialic acid derivatives and analogues. Searching for new biological characteristics of sialic acids in cells have also been extensively studied these days. In this paper, main stream discoveries and advancements are provided , also discussions of possible mechanisms and hypotheses are invoked.展开更多
The purpose of this work is to perform a detailed study of carbohydrate specificity of the new extracellular bacilli lectins which is considered to determine mechanisms of the lectins action. Sources of lectins were b...The purpose of this work is to perform a detailed study of carbohydrate specificity of the new extracellular bacilli lectins which is considered to determine mechanisms of the lectins action. Sources of lectins were bacterial strains from Ukrainian collection of microorganisms. The optimized protocol of bacilli lectins isolation and purification included precipitation with ammonium sulfate with subsequent gel filtration chromatography on Sepharose CL-6B. Hemagglutinating activity of bacilli lectins and their fine carbohydrate specificity to sialic acids and their derivatives as well as sialic asid-containing and asialic glycoconjugates were studied. The ability of extracellular bacilli lectins to discriminate a- and 13-conformation of carbohydrate molecule and the type of connection between the monomers was determined. Studied lectins showed the most affinity to glycoconjugates containing both types of sialic acids （N-acetylneuraminic acid （Neu5Ac） and N-glycolylneuraminic acid （NeuGc）） and it is supposed to be a basis of their diagnostic and analytical potential.展开更多
The properties of modified biomaterial are gaining more and more importance in drug delivery systems.Sialic acid(SA)and polysialic acid(PSA)serve as endogenous substances,which are non-immunogenic and biodegradable.At...The properties of modified biomaterial are gaining more and more importance in drug delivery systems.Sialic acid(SA)and polysialic acid(PSA)serve as endogenous substances,which are non-immunogenic and biodegradable.At the same time,SA modification of the drugs/carriers can enhance the uptake of tumor cell and retention in brain;PSA modifi-cation can reduce the immunogenicity of the proteins or polypeptides and increase circulation time of the modified drugs/carriers in the blood,thus achieving active targeting effect.These properties offer a variety of opportunities for applications in drug delivery systems.This article summarizes the biological functions of SA and PSA and presents the technologies of SA/PSA modified small molecule drugs,proteins and carriers in drug delivery systems.展开更多
Checkpoint inhibitors are designed to rejuvenate depleted or suppressed T cells in the tumor microenvironment,relying on the immune system to control and kill tumors.However,accumulating evidence indicates that tumor-...Checkpoint inhibitors are designed to rejuvenate depleted or suppressed T cells in the tumor microenvironment,relying on the immune system to control and kill tumors.However,accumulating evidence indicates that tumor-infiltrating neutrophils impede the proliferation and activation of T cells and determine the resistance to checkpoint blockade and chemotherapy.In this study,sialic acid ligand-modified colchicine derivative phospholipid complexes specifically targeted tumor-associated neutrophils in the peripheral blood,blocked neutrophil accumulation in tumors,and attenuated the inhibitory effect of infiltrating neutrophils on T cells.Neutrophil blocking therapy enhanced the immunotherapy effect of the PD-L1 antibody in S180 advanced tumors and 4T1 breast cancer.Our study found that PD-L1 antibody monotherapy increased the tumor infiltration of immunosuppressive neutrophils.Combination therapy with neutrophil blocking can greatly reduce tumor-infiltrating neutrophils and increase the proliferation of cytotoxic CD8^(+) T lymphocytes in the tumor.The combination therapy significantly improved the survival rate of mice with advanced S180 tumors and increased the sensitivity of immune checkpoint inhibitors to 4T1 cold tumors.展开更多
Objective To investigate the apoptosis of epididyrnis epithelium and the change of epididymissialic acid following torsed/detorsed testes. Methods Twenty four adult male Sprague-Dawley rats were subjected to unilatera...Objective To investigate the apoptosis of epididyrnis epithelium and the change of epididymissialic acid following torsed/detorsed testes. Methods Twenty four adult male Sprague-Dawley rats were subjected to unilateral 720 testicular torsion with the duration of 2h and 4h, then repaired. The ischemic epididymis were collected for detecting the content of sialic acid by using spectrophotometry and the apoptosis with TUNEL technique. Results There were no statistically significant difference in the apoptosis of epididymis epithelium [(9.51± 2.78)% vs (6.34±1. 98)%] and the content of epididymis sialic acid(23, 3851 ± 9. 2199mg/mgprot vs 19. 3661 6. 3373mg/mgprot) at 24h between following 2h-torsed/detorsed testes and those of sham group. There were statistically significant difference in the apopotosis of epididymis epithelium[ (46. 81 ±3. 55)% vs (6. 34±1. 98) % ] and the content of epididymis sialic acid (13. 7249±7. 8006mg/mgprot vs 19. 3661±6. 3373mg/mgprot) at 24h between following 4h-torsed/detorsed testes and those of sham group(P <0. 05). Conclusion The results suggest that the sialic acid-secreting-function of epididymis remain normal at 24h following 2h-torsed/detorsed testes, while the apoptosis index of epididymis epithelium do not increase. The epididymis would be injured at 24h following 4h-torsed/detorsed testes, while the apoptosis index increased.展开更多
Development of sensitive and accurate methods for sialic acid(SA) determination is of great significance in early cancer diagnosis.Here,a colorimetric-assisted Photoelectrochemical(PEC) sensor was constructed for SA d...Development of sensitive and accurate methods for sialic acid(SA) determination is of great significance in early cancer diagnosis.Here,a colorimetric-assisted Photoelectrochemical(PEC) sensor was constructed for SA detection based on the two pairs of cis-diol groups in SA molecule.With the specific recognition of SA via the two pairs of cis-diol groups,the prepared gold-modified Bi_(2)S_(3)(AuNPs@Bi_(2)S_(3)) and metal organic framework(Au@PCN-224) were introduced to the electrode and formed a sandwich structure.Based on the properties of inert electroconductivity and nanozyme of the PCN-224,dual-readout of photocurrent and visualization was achieved with the presence of 3',3',5',5'-tetramethylbenzidine(TMB).Moreover,to intensify the visualization signal,Ce^(3+) was employed as the mediator to boost the catalysis capability by transferring energy from PCN-224 surface to the whole system.With the unique SA recognition and the mediation of Ce^(3+),both the photocurrent and the visualization signals sensitively responded with the SA concentration linearly.The present method showed greatly high sensitivity,selectivity and accuracy for SA detection with a limit of detection of 1.44μmol/L and a wide linear range of 5-1000μmol/L.This method provided a new promising platform for SA detection and a potential strategy for design of novel biosensors with dual-model readout.展开更多
Lactoferrin(Lf-α)is a major constithent of the secondary granules of neutrophils, and is thought to be involved in bacteriostasis through high affinity binding of plasma Fe required for microbial growth.Lf-αis also ...Lactoferrin(Lf-α)is a major constithent of the secondary granules of neutrophils, and is thought to be involved in bacteriostasis through high affinity binding of plasma Fe required for microbial growth.Lf-αis also the major Fe binding protein in milk. Fe bound to Lf-αis available for metabolic use.but the mechanism of Fe release from Lf-αis unknown.Treatment of human Lf-α with neuraminidase to remove sialic acid residues reduced its ability to bind Fe and caused release of Fe already bound to the protein. Reduction in Fe binding capacity was dependent on time of exposure to and concentration of neuraminidase,and was due to Lf-αloss or degradation. Readdition of sialic arid to desialylated Lf -a using a-2, 6-sialyltransferase restored Fe binding.The results suggest that sialylationdesialylation reactions could play a role in physiologic binding and release of Fe from the very high affinity binding sites of Lf -α.展开更多
Serum lipid-bound sialic acid (LSA) assay was evaluated for differential diagnosis between benign and malignant pulmonary disease.Mean serum LSA for normal controls was 13.7±3.7 mg/dl and the upper limit of the ...Serum lipid-bound sialic acid (LSA) assay was evaluated for differential diagnosis between benign and malignant pulmonary disease.Mean serum LSA for normal controls was 13.7±3.7 mg/dl and the upper limit of the normal value was set at 19.8 mg/dl (95% confidence limit,one side).The specificity was 97.l% (95% confidence interval was 93.8%, 100.0%).The mean for benign pulmonary disease was 1 7.l±5.l mg/dl,the specificity was 89.l% (95% confidence interval was 80.9%,97.3%), and the sensitivity was 10.9%.The mean for malignant pulmonary disease was 27.l±7.9 mg/dl, and the sensitivity was 93.3%(95% confidence interval was 88.5%, 98.1%).The serum LSA levels for different malignant pulmonary diseases were different between small cell carcinoma and adenocarcinoma. The results indicate that serum LSA assay might be used as tumor marker to differentiate lung cancer from normal subjects or benign lung disease.展开更多
Meningitis is often associated with cerebral compromise which may be responsible for neurological squeal in nearly half of the survivors. Little is known about the mechanisms of Central Nervous System （CNS） involvem...Meningitis is often associated with cerebral compromise which may be responsible for neurological squeal in nearly half of the survivors. Little is known about the mechanisms of Central Nervous System （CNS） involvement in bacterial meningitis. The present study was undertaken to assess the changes in biochemical parameters including glucose, protein, Sialic Acid （SA） and various enzymes like Aspartate Aminotransferase （AST）, Alanine Aminotransferase （ALT）, Creatine Kinase （CK）, Gamma Glutamyltranspeptidase 7 （GGTP） and Lactate Dehydrogenase （LDH） have been determined in the Cerebrospinal Fluid （CSF） of the meningitis patients （n = 26） and compared with control subjects （n = 26）. Total Protein, CK, SA （P 〈 0.02）, AST （P 〈 0.001） and ALT （P 〈 0.0001） of meningitis patients were significantly higher, whereas, glucose （P 〈 0.05） and Gamma Glutamyltranspeptidase （GGT） （P 〈 0.01 and P 〈 0.05, respectively） were significantly lower than those of the controls. This study suggests that loss of integrity of brain-CSF barriers, sialic acid and enzyme profiles may contribute to the severity and neurological complications of meningitis.展开更多
Recent research has indicated that sialic acid,such as free sialic acid(N-acetylneuraminic acid,Neu5Ac)and bound sialic acid(3ʹ-sialyllactose,3ʹ-SL),can ameliorate disorders associated with glycolipid metabolism,altho...Recent research has indicated that sialic acid,such as free sialic acid(N-acetylneuraminic acid,Neu5Ac)and bound sialic acid(3ʹ-sialyllactose,3ʹ-SL),can ameliorate disorders associated with glycolipid metabolism,although the underlying mechanisms have yet to be determined.We examined the effects of 3ʹ-SL on glycolipid metabolism in mice fed a high-fat diet.Male C57BL/6J mice were divided into 6 groups:2 model control groups(normal and high-fat diets)and 4 intervention groups(Neu5Ac,and low,moderate,and high-dose 3ʹ-SL).After 8 weeks of continuous gavage intervention,mice in the 3ʹ-SL intervention groups had lower body weight and total fat content;reduced fasting blood glucose,triglycerides,low-density lipoproteins and oxidized-low-density lipoproteins;and increased high-density lipoproteins,but no dosage-dependent of 3ʹ-SL intervention was found,moderate-dose 3ʹ-SL intervention as optimal for further exploration.3ʹ-SL intervention could increase respiratory exchange ratio,energy expenditure,and amount of exercise performed.3ʹ-SL increased the colonic abundances of Akkermansia,Lactobacillus,and Bacteroides,and reduced those of Erysipelatoclostridium,Faecalibaculum,and Aldercreutzia.Changes were also observed in colonic metabolites,and liver gene transcript and metabolites,which were mainly enriched in bile secretion,taurine and hypotaurine metabolism,and insulin resistance.Additionally,3ʹ-SL was observed to regulate genes associated with physiological rhythms,including Clock,Per2,Cry1,and Bhihe41.Collectively,our findings indicate that 3ʹ-SL can contribute to the prevention and control of disorders associated with glucose and lipid metabolism caused by high-fat diets.Compared with Neu5Ac,3ʹ-SL intervention can more effectively ameliorate intestinal flora disorders,enhance bile acid circulation,increase tissue energy expenditure,and reduce lipid synthesis,thereby promoting lipid-lowering effects mediated via the gut-liver axis,and can also enhance energy metabolism and alleviate disorders of glucolipid metabolism by altering physiological rhythms in high fat-diet mice.展开更多
Aim: To study the effect of 5-nitro-2-fumldehyde semicarbazone (nitrofurazone), a derivative of nitrofuran, onmale reproductive organs of Parkes (P) swain mice. Methods: Mice were given nitrofurazone orally at a dose ...Aim: To study the effect of 5-nitro-2-fumldehyde semicarbazone (nitrofurazone), a derivative of nitrofuran, onmale reproductive organs of Parkes (P) swain mice. Methods: Mice were given nitrofurazone orally at a dose of 64mg/kg body weight per day, for 10 and 20 days, and were killed 24 h and/or 56 days after the last treatment. Histo-logical appearance of testis, motility and number of spermatozoa in cauda epididymidis, and biochemical indices in epi-didymis and seminal vesicle were evaluated. Results: Histologically, testis showed marked regressive changes inthe seminiferous tubules in mice treated with nitrofurazone. Ten days after treatment, there was much depletion of germcells in the seminiferous tubules, and the germinal epithelium was lined mainly with Sertoli cells, spermatogonia, sper-matocytes, and a few round spermatids; intraepithelial vacuoles and multinucleated giant cells were also observed intubules. By 20 days, regressive changes in the seminiferous tubules were further pronounced, and pachytene spermato-cytes were the most advanced germ cells noticed in the tubules. In severe cases, the tubules were lined with a thin layerof Sertoli cells and spermatogonia. The treatment also caused marked reductions in the motility and number of sperma-tozoa in the cauda epididymidis, in weight and the level of fructose in the seminal vesicle, and in sialic acid level in theepididymis. Fifty six days after drag withdrawal, the alterations induced in the reproductive organs returned to controllevels. Conclusion: Our results suggest that nitrofurazone treatment in P mice induces marked alterations in themale reproductive organs, and that the alterations are reversible following cessation of treatment.(Asian J Androl 2001 Mar; 3: 39-44)展开更多
Aberrant expression of glycoconjugates occurs during malignant transformation of cancer cells.Overexpression of sialoglycoconjugates in particular may play an important role in the progression,i.e.,invasion or metasta...Aberrant expression of glycoconjugates occurs during malignant transformation of cancer cells.Overexpression of sialoglycoconjugates in particular may play an important role in the progression,i.e.,invasion or metastasis,of cancer.Various types of sialoglycoconjugates have been investigated to clarify their biological significance and clinical utility in diagnosing and treating colorectal cancer.This review focuses specifically on expression of mucin(MUC)1 and it suggests that MUC1with the specific structure of a sialo-oligosaccharide has biological significance in determining the metastatic potential of colorectal cancer cells and clinicopathological utility in evaluating the effectiveness of treatments and the prognosis for patients with colorectal cancer.Further studies are expected to contribute to the expanded use of cancer-associated sialoglycoconjugates in cancer diagnosis and therapy.展开更多
Aim： To study the effect of piperine on the epididymal antioxidant system of adult male rats. Methods： Adult male rats were orally administered piperine at doses of 1 mg/kg, 10 mg/kg and 100 mg/kg body weight each d...Aim： To study the effect of piperine on the epididymal antioxidant system of adult male rats. Methods： Adult male rats were orally administered piperine at doses of 1 mg/kg, 10 mg/kg and 100 mg/kg body weight each day for 30 consecutive days. Twenty-four hours after the last treatment, the rats were weighed and killed with ether and the epididymis was dissected from the bodies. Sperm collected from the cauda region of the epididymis was used for the assessment of its count, motility and viability. Caput, corpus and cauda regions of the epididymis were separated and homogenized separately to obtain 10 % homogenates. The supernatants were used for the assays of sialic acid, superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, lipid peroxidation and hydrogen peroxide generation. Results： Body weight of the piperine-treated rats remained unchanged. The weights of the caput, corpus and cauda regions of the epididymis significantly decreased at dose of 100 mg/kg. Epididymal sperm count and motility decreased at 10 mg/kg and 100 mg/kg, and sperm viability decreased significantly at 100 mg/kg. Sialic acid levels in the epididymis decreased significantly at 100 mg/kg while significant decrease in the cauda region alone was observed at 10 mg/kg. A significant decline in the activities of superoxide dismutase, catalase, glutathione peroxidase and glutathione reductase, along with an increase in hydrogen peroxide generation and lipid peroxidation were observed at 10 mg/kg and 100 mg/kg. Conclusion： Piperine caused a decrease in the activity of antioxidant enzymes and sialic acid levels in the epididymis and thereby increased reactive oxygen species levels that could damage the epididymal environment and sperm function.展开更多
Abstract Aim: To evaluate the antifertility effect ofAlstonia scholaris bark extract in male rats. Methods: In male Wistar rats Alstonia scholaris bark extract was given by oral route at a dose of 200 mg/day for 60 da...Abstract Aim: To evaluate the antifertility effect ofAlstonia scholaris bark extract in male rats. Methods: In male Wistar rats Alstonia scholaris bark extract was given by oral route at a dose of 200 mg/day for 60 days. The fertility and testicular function were assessed by mating tests, sperm motility, sperm concentration, biochemical indices and testicular cell population dynamics. Results: Oral feeding with the extract at a dose of 200 mg/day for the period of 60 days did not cause body weight loss, while the weights of testes, epididymides, seminal vesicle and ventral prostate were significantly reduced. The production of step-19 spermatids was reduced by 79.6% in treated rats. The population of preleptotene and pachytene spermatocytes were decreased by 61.9% and 60.1%, respectively. Spermatogonia and Sertoli cell population were also affected. The seminiferous tubule and Leydig cell nuclear area were reduced significantly (P<0.01) when compared to the controls. Reduced sperm count and motility resulted in a total suppression of fertility. A significant fall in the protein and sialic acid content of the testes, epididymides, seminal vesicle and ventral prostate as well as glycogen content of testes were also noticed. The fructose content in the seminal vesicle was lowered whereas the testicular cholesterol was elevated as compared with the controls. The following compounds were obtained from the extract with chromatographic separation over Si-gel column: α-amyrin, β-amyrin, lupiol acetate, venenative, rhazine and yohimbine. Conclusion: At the dose level employed, Alstonia scholaris bark extract has a significant antifertility effect in male rats; the primary site of action may be post meiotic germ cells (Step 19 spermatids).展开更多
P[3]rotavirus(RV)has been identified in many species,including human,simian,dog,and bat.Several glycans,including sialic acid,histo-blood group antigens(HBGAs)are reported as RV attachment factors.The glycan binding s...P[3]rotavirus(RV)has been identified in many species,including human,simian,dog,and bat.Several glycans,including sialic acid,histo-blood group antigens(HBGAs)are reported as RV attachment factors.The glycan binding specificity of different P[3]RV VP8*s were investigated in this study.Human HCR3 A and dog P[3]RV VP8*s recognized glycans with terminal sialic acid and hemagglutinated the red blood cells,while bat P[3]VP8*showed neither binding to glycans nor hemagglutination.However,the bat P[3]VP8*mutant of C189 Y obtained the ability to hemagglutinate the red blood cells,while human P[3]HCR3 A/M2-102 mutants of Y189 C lost the ability.Sequence alignment and structural analysis indicated that residue 189 played an important role in the ligand recognition and may contribute to the cross-species transmission.Structural superimposition exhibited that bat P[3]VP8*model was quite different from the simian P[3]Rhesus rotavirus(RRV)P[3]VP8*,indicating that bat P[3]RV was relatively distinct and partially contributed to the no binding to tested glycans.These results promote our understanding of P[3]VP8*/glycans interactions and the potential transmission of bat/human P[3]RVs,offering more insight into the RV infection and prevalence.展开更多
In the glomeruli,mesangial cells produce mesangial matrix while podocytes wrap glomerular capillaries with cellular extensions named foot processes and tether the glomerular basement membrane(GBM).The turnover of the ...In the glomeruli,mesangial cells produce mesangial matrix while podocytes wrap glomerular capillaries with cellular extensions named foot processes and tether the glomerular basement membrane(GBM).The turnover of the mature GBM and the ability of adult podocytes to repair injured GBM are unclear.The actin cytoskeleton is a major cytoplasmic component of podocyte foot processes and links the cell to the GBM.Predominant components of the normal glomerular extracellular matrix(ECM)include glycosaminoglycans,proteoglycans,laminins,fibronectin-1,and several types of collagen.In patients with diabetes,multiorgan composition of extracellular tissues is anomalous,including the kidney,so that the constitution and arrangement of glomerular ECM is profoundly altered.In patients with diabetic kidney disease(DKD),the global quantity of glomerular ECM is increased.The level of sulfated proteoglycans is reduced while hyaluronic acid is augmented,compared to control subjects.The concentration of mesangial fibronectin-1 varies depending on the stage of DKD.Mesangial type III collagen is abundant in patients with DKD,unlike normal kidneys.The amount of type V and type VI collagens is higher in DKD and increases with the progression of the disease.The GBM contains lower amount of type IV collagen in DKD compared to normal tissue.Further,genetic variants in theα3 chain of type IV collagen may modulate susceptibility to DKD and end-stage kidney disease.Human cellular models of glomerular cells,analyses of human glomerular proteome,and improved microscopy procedures have been developed to investigate the molecular composition and organization of the human glomerular ECM.展开更多
E dible bird’s nest(EBN)hydrolysates have been proven to exhibit enhanced bioactivities.However,being a macromolecule,fractions with different molecular weights would have different properties and bioactivities.Hence...E dible bird’s nest(EBN)hydrolysates have been proven to exhibit enhanced bioactivities.However,being a macromolecule,fractions with different molecular weights would have different properties and bioactivities.Hence,this research was aimed to determine the chemical properties and antioxidant activities of freezedried(EBN_(FD))and spray-dried EBN(EBN_(SD))hydrolysates fractionated using gel permeation chromatography(GPC).Overall,two well-separated fractions were identified(EBN_(fFD1),EBN_(fFD2),EBN_(fSD1) and EBN_(fSD2)).EBNFD demonstrated significantly higher(P≤0.05)peptide(3.6%),total carbohydrate(27.7%)and sialic acid(18.2%)contents than that of EBNSD.Similar trend was observed in low molecular weight fractionates(EBN_(fFD2) and EBN_(fSD2)).Meanwhile,the first fractionates(EBN_(fFD1) and EBN_(fSD1))exhibited significantly higher(P≤0.05)hydroxyl radical(·OH)scavenging activity.Fourier transform infrared(FTIR)spectroscopy demonstrated that all EBN fractionates have similar spectrum,except in the region of N—H(amideⅡ)and C—H alkyl group.In conclusion,EBN fractionates with different molecular weights showed different chemical properties and antioxidant activities.展开更多
Increasing evidence indicates that sialic acid plays an important role during nerve regeneration. Sialic acids can be modified in vitro as well as in vivo using metabolic oligosaccharide engineering of the N-awl side ...Increasing evidence indicates that sialic acid plays an important role during nerve regeneration. Sialic acids can be modified in vitro as well as in vivo using metabolic oligosaccharide engineering of the N-awl side chain. N-Propionylmannosamine （ManNProp） increases neurite outgrowth and accelerates the reestablishment of functional synapses in vitro. We investigated the influence of systemic ManNProp application using a specific in vivo mouse model. Using mice expressing axonal fluorescent proteins, we quantified the extension of regenerating axons, the number of regenerating axons, the number of arborising axons and the number of branches per axon 5 days after injury. Sciatic nerves from non-expressing mice were grafted into those expressing yellow fluorescent protein. We began a twice-daily intraperitoneal application of either peracetylated ManNProp （200 mg/kg） or saline solution 5 days before injury, and continued it until nerve harvest （5 days after transection）. ManNProp significantly increased the mean distance of axonal regeneration （2.49 mm vs. 1.53 mm; P 〈 0.005） and the number of arborizing axons （21% vs. 16%; P = 0.008） 5 days after sciatic nerve grafting. ManNProp did not affect the number of regenerating axons or the number of branches per arborizing axon. The biochemical glycoengineering of the N-acyl side chain of sialic acid might be a promising approach for improving peripheral nerve regeneration.展开更多
Aim: To evaluate the effect of aqueous Carica papaya seed extract on microenvironment of cauda epididymis.Methods: Adult male albino rats were intramuscularly administered with 0 (control) or 0.5 mg papaya seed ex-tra...Aim: To evaluate the effect of aqueous Carica papaya seed extract on microenvironment of cauda epididymis.Methods: Adult male albino rats were intramuscularly administered with 0 (control) or 0.5 mg papaya seed ex-tract/kg body weight for 7 days. Cauda epididymal tubular content was collected by micropuncture technique; epididy-mal luminal fluid and sperm pellets were separately analyzed. Results: The results revealed that the extract treat-ment caused significant reduction, as compared with control, in total protein and sialic acid contents in both epididymalfluid and sperm pellet. As compared with control, significantly lowered acid phosphatase activity was recorded in spermpellet but was higher in epididymal fluid after the treatment. The extract treatment also caused significant reduction inlevel of inorganic phosphorus in the epididymal fluid. Conclusion: It is concluded that the aqueous papaya seed ex-tract alters cauda epididymal microenvironment.展开更多
Lipid peroxide (LPO) plays pivotal roles in the process and development of many diseases. In this work, we studied the inhibitory effect of probimane (Pro), a Chinese anticancer agent, on erythrocyte LPO and the inter...Lipid peroxide (LPO) plays pivotal roles in the process and development of many diseases. In this work, we studied the inhibitory effect of probimane (Pro), a Chinese anticancer agent, on erythrocyte LPO and the interaction of Pro with sialic acids (sia). Malondialdehyde (MDA) of erythrocytes activated by hydrogen peroxide was measured. Pro was found to inhibit the product of LPO induced by hydrogen peroxide in a non-enzyme system of both rabbit and human erythrocytes in the absence of doxorubicin. Sia were found to enhance LPO production and the activity of N-glycolylneuraminic acid (NeuGc) was about 5 times higher than that of N-acetylneuraminic acid (5AcNeu) at equivalent concentrations. Pro inhibited the increased LPO production induced by sia and the activity of Pro against LPO with 5AcNeu was almost twofold higher than that of Pro alone. It suggests that Pro be an inhibitor of LPO (free radicals) and as a functional modulator of sia in body.展开更多
文摘Sialic acids (neuraminic acids) are a special series of 9 carbon ring negatively charged carbohydrates, which has been found to be selectively changed in malignant cells from structures (both synthesis and structure modifications) to functions (up and down regulation in cells). Sialic acids, in single forms or conjugates, have been systematically studied both in lab and in clinics by GC, GC MS, NMR, HPTLC, HPLC and other modern analytical means. Sialic acids and related conjugates are predicted to be used in cancer diagnosis, cancer prognostic forecasting, designing of cancer chemotherapy regimens, uncovering carcinogenetic processes and neoplasm metastasis. Tumor cell regulative systems and pathways are correlated with sialic acids, which can be applied to prognostic evaluation of cancer patients, and antimetastatic chemotherapy by sialic acid derivatives and analogues. Searching for new biological characteristics of sialic acids in cells have also been extensively studied these days. In this paper, main stream discoveries and advancements are provided , also discussions of possible mechanisms and hypotheses are invoked.
文摘The purpose of this work is to perform a detailed study of carbohydrate specificity of the new extracellular bacilli lectins which is considered to determine mechanisms of the lectins action. Sources of lectins were bacterial strains from Ukrainian collection of microorganisms. The optimized protocol of bacilli lectins isolation and purification included precipitation with ammonium sulfate with subsequent gel filtration chromatography on Sepharose CL-6B. Hemagglutinating activity of bacilli lectins and their fine carbohydrate specificity to sialic acids and their derivatives as well as sialic asid-containing and asialic glycoconjugates were studied. The ability of extracellular bacilli lectins to discriminate a- and 13-conformation of carbohydrate molecule and the type of connection between the monomers was determined. Studied lectins showed the most affinity to glycoconjugates containing both types of sialic acids （N-acetylneuraminic acid （Neu5Ac） and N-glycolylneuraminic acid （NeuGc）） and it is supposed to be a basis of their diagnostic and analytical potential.
基金the National Natural Science Foundation of China(Grant No.81373334).
文摘The properties of modified biomaterial are gaining more and more importance in drug delivery systems.Sialic acid(SA)and polysialic acid(PSA)serve as endogenous substances,which are non-immunogenic and biodegradable.At the same time,SA modification of the drugs/carriers can enhance the uptake of tumor cell and retention in brain;PSA modifi-cation can reduce the immunogenicity of the proteins or polypeptides and increase circulation time of the modified drugs/carriers in the blood,thus achieving active targeting effect.These properties offer a variety of opportunities for applications in drug delivery systems.This article summarizes the biological functions of SA and PSA and presents the technologies of SA/PSA modified small molecule drugs,proteins and carriers in drug delivery systems.
基金This work was supported by the National Natural Science Foundation of China[grant number:81973271].
文摘Checkpoint inhibitors are designed to rejuvenate depleted or suppressed T cells in the tumor microenvironment,relying on the immune system to control and kill tumors.However,accumulating evidence indicates that tumor-infiltrating neutrophils impede the proliferation and activation of T cells and determine the resistance to checkpoint blockade and chemotherapy.In this study,sialic acid ligand-modified colchicine derivative phospholipid complexes specifically targeted tumor-associated neutrophils in the peripheral blood,blocked neutrophil accumulation in tumors,and attenuated the inhibitory effect of infiltrating neutrophils on T cells.Neutrophil blocking therapy enhanced the immunotherapy effect of the PD-L1 antibody in S180 advanced tumors and 4T1 breast cancer.Our study found that PD-L1 antibody monotherapy increased the tumor infiltration of immunosuppressive neutrophils.Combination therapy with neutrophil blocking can greatly reduce tumor-infiltrating neutrophils and increase the proliferation of cytotoxic CD8^(+) T lymphocytes in the tumor.The combination therapy significantly improved the survival rate of mice with advanced S180 tumors and increased the sensitivity of immune checkpoint inhibitors to 4T1 cold tumors.
文摘Objective To investigate the apoptosis of epididyrnis epithelium and the change of epididymissialic acid following torsed/detorsed testes. Methods Twenty four adult male Sprague-Dawley rats were subjected to unilateral 720 testicular torsion with the duration of 2h and 4h, then repaired. The ischemic epididymis were collected for detecting the content of sialic acid by using spectrophotometry and the apoptosis with TUNEL technique. Results There were no statistically significant difference in the apoptosis of epididymis epithelium [(9.51± 2.78)% vs (6.34±1. 98)%] and the content of epididymis sialic acid(23, 3851 ± 9. 2199mg/mgprot vs 19. 3661 6. 3373mg/mgprot) at 24h between following 2h-torsed/detorsed testes and those of sham group. There were statistically significant difference in the apopotosis of epididymis epithelium[ (46. 81 ±3. 55)% vs (6. 34±1. 98) % ] and the content of epididymis sialic acid (13. 7249±7. 8006mg/mgprot vs 19. 3661±6. 3373mg/mgprot) at 24h between following 4h-torsed/detorsed testes and those of sham group(P <0. 05). Conclusion The results suggest that the sialic acid-secreting-function of epididymis remain normal at 24h following 2h-torsed/detorsed testes, while the apoptosis index of epididymis epithelium do not increase. The epididymis would be injured at 24h following 4h-torsed/detorsed testes, while the apoptosis index increased.
基金supported by grants awarded by the National Natural Science Foundation of China(Nos.22174086,21775089 and 22074080)Changjiang Scholar Program of the Ministry of Education of China(No.Q2019258)+2 种基金Natural Science Foundation of Shandong Province(Nos.ZR2020MB056 and ZR2020KB020)Taishan Scholar Program of Shandong Province(No.tsqn201909106)College Students Innovation and Entrepreneurship Training Project of Shandong Province(No.S201910446019)。
文摘Development of sensitive and accurate methods for sialic acid(SA) determination is of great significance in early cancer diagnosis.Here,a colorimetric-assisted Photoelectrochemical(PEC) sensor was constructed for SA detection based on the two pairs of cis-diol groups in SA molecule.With the specific recognition of SA via the two pairs of cis-diol groups,the prepared gold-modified Bi_(2)S_(3)(AuNPs@Bi_(2)S_(3)) and metal organic framework(Au@PCN-224) were introduced to the electrode and formed a sandwich structure.Based on the properties of inert electroconductivity and nanozyme of the PCN-224,dual-readout of photocurrent and visualization was achieved with the presence of 3',3',5',5'-tetramethylbenzidine(TMB).Moreover,to intensify the visualization signal,Ce^(3+) was employed as the mediator to boost the catalysis capability by transferring energy from PCN-224 surface to the whole system.With the unique SA recognition and the mediation of Ce^(3+),both the photocurrent and the visualization signals sensitively responded with the SA concentration linearly.The present method showed greatly high sensitivity,selectivity and accuracy for SA detection with a limit of detection of 1.44μmol/L and a wide linear range of 5-1000μmol/L.This method provided a new promising platform for SA detection and a potential strategy for design of novel biosensors with dual-model readout.
文摘Lactoferrin(Lf-α)is a major constithent of the secondary granules of neutrophils, and is thought to be involved in bacteriostasis through high affinity binding of plasma Fe required for microbial growth.Lf-αis also the major Fe binding protein in milk. Fe bound to Lf-αis available for metabolic use.but the mechanism of Fe release from Lf-αis unknown.Treatment of human Lf-α with neuraminidase to remove sialic acid residues reduced its ability to bind Fe and caused release of Fe already bound to the protein. Reduction in Fe binding capacity was dependent on time of exposure to and concentration of neuraminidase,and was due to Lf-αloss or degradation. Readdition of sialic arid to desialylated Lf -a using a-2, 6-sialyltransferase restored Fe binding.The results suggest that sialylationdesialylation reactions could play a role in physiologic binding and release of Fe from the very high affinity binding sites of Lf -α.
文摘Serum lipid-bound sialic acid (LSA) assay was evaluated for differential diagnosis between benign and malignant pulmonary disease.Mean serum LSA for normal controls was 13.7±3.7 mg/dl and the upper limit of the normal value was set at 19.8 mg/dl (95% confidence limit,one side).The specificity was 97.l% (95% confidence interval was 93.8%, 100.0%).The mean for benign pulmonary disease was 1 7.l±5.l mg/dl,the specificity was 89.l% (95% confidence interval was 80.9%,97.3%), and the sensitivity was 10.9%.The mean for malignant pulmonary disease was 27.l±7.9 mg/dl, and the sensitivity was 93.3%(95% confidence interval was 88.5%, 98.1%).The serum LSA levels for different malignant pulmonary diseases were different between small cell carcinoma and adenocarcinoma. The results indicate that serum LSA assay might be used as tumor marker to differentiate lung cancer from normal subjects or benign lung disease.
文摘Meningitis is often associated with cerebral compromise which may be responsible for neurological squeal in nearly half of the survivors. Little is known about the mechanisms of Central Nervous System （CNS） involvement in bacterial meningitis. The present study was undertaken to assess the changes in biochemical parameters including glucose, protein, Sialic Acid （SA） and various enzymes like Aspartate Aminotransferase （AST）, Alanine Aminotransferase （ALT）, Creatine Kinase （CK）, Gamma Glutamyltranspeptidase 7 （GGTP） and Lactate Dehydrogenase （LDH） have been determined in the Cerebrospinal Fluid （CSF） of the meningitis patients （n = 26） and compared with control subjects （n = 26）. Total Protein, CK, SA （P 〈 0.02）, AST （P 〈 0.001） and ALT （P 〈 0.0001） of meningitis patients were significantly higher, whereas, glucose （P 〈 0.05） and Gamma Glutamyltranspeptidase （GGT） （P 〈 0.01 and P 〈 0.05, respectively） were significantly lower than those of the controls. This study suggests that loss of integrity of brain-CSF barriers, sialic acid and enzyme profiles may contribute to the severity and neurological complications of meningitis.
基金supported by the Incubation Fund of Zhongshan Hospital,Fudan University(Xiamen Branch)(2020ZSXMYS24).
文摘Recent research has indicated that sialic acid,such as free sialic acid(N-acetylneuraminic acid,Neu5Ac)and bound sialic acid(3ʹ-sialyllactose,3ʹ-SL),can ameliorate disorders associated with glycolipid metabolism,although the underlying mechanisms have yet to be determined.We examined the effects of 3ʹ-SL on glycolipid metabolism in mice fed a high-fat diet.Male C57BL/6J mice were divided into 6 groups:2 model control groups(normal and high-fat diets)and 4 intervention groups(Neu5Ac,and low,moderate,and high-dose 3ʹ-SL).After 8 weeks of continuous gavage intervention,mice in the 3ʹ-SL intervention groups had lower body weight and total fat content;reduced fasting blood glucose,triglycerides,low-density lipoproteins and oxidized-low-density lipoproteins;and increased high-density lipoproteins,but no dosage-dependent of 3ʹ-SL intervention was found,moderate-dose 3ʹ-SL intervention as optimal for further exploration.3ʹ-SL intervention could increase respiratory exchange ratio,energy expenditure,and amount of exercise performed.3ʹ-SL increased the colonic abundances of Akkermansia,Lactobacillus,and Bacteroides,and reduced those of Erysipelatoclostridium,Faecalibaculum,and Aldercreutzia.Changes were also observed in colonic metabolites,and liver gene transcript and metabolites,which were mainly enriched in bile secretion,taurine and hypotaurine metabolism,and insulin resistance.Additionally,3ʹ-SL was observed to regulate genes associated with physiological rhythms,including Clock,Per2,Cry1,and Bhihe41.Collectively,our findings indicate that 3ʹ-SL can contribute to the prevention and control of disorders associated with glucose and lipid metabolism caused by high-fat diets.Compared with Neu5Ac,3ʹ-SL intervention can more effectively ameliorate intestinal flora disorders,enhance bile acid circulation,increase tissue energy expenditure,and reduce lipid synthesis,thereby promoting lipid-lowering effects mediated via the gut-liver axis,and can also enhance energy metabolism and alleviate disorders of glucolipid metabolism by altering physiological rhythms in high fat-diet mice.
文摘Aim: To study the effect of 5-nitro-2-fumldehyde semicarbazone (nitrofurazone), a derivative of nitrofuran, onmale reproductive organs of Parkes (P) swain mice. Methods: Mice were given nitrofurazone orally at a dose of 64mg/kg body weight per day, for 10 and 20 days, and were killed 24 h and/or 56 days after the last treatment. Histo-logical appearance of testis, motility and number of spermatozoa in cauda epididymidis, and biochemical indices in epi-didymis and seminal vesicle were evaluated. Results: Histologically, testis showed marked regressive changes inthe seminiferous tubules in mice treated with nitrofurazone. Ten days after treatment, there was much depletion of germcells in the seminiferous tubules, and the germinal epithelium was lined mainly with Sertoli cells, spermatogonia, sper-matocytes, and a few round spermatids; intraepithelial vacuoles and multinucleated giant cells were also observed intubules. By 20 days, regressive changes in the seminiferous tubules were further pronounced, and pachytene spermato-cytes were the most advanced germ cells noticed in the tubules. In severe cases, the tubules were lined with a thin layerof Sertoli cells and spermatogonia. The treatment also caused marked reductions in the motility and number of sperma-tozoa in the cauda epididymidis, in weight and the level of fructose in the seminal vesicle, and in sialic acid level in theepididymis. Fifty six days after drag withdrawal, the alterations induced in the reproductive organs returned to controllevels. Conclusion: Our results suggest that nitrofurazone treatment in P mice induces marked alterations in themale reproductive organs, and that the alterations are reversible following cessation of treatment.(Asian J Androl 2001 Mar; 3: 39-44)
文摘Aberrant expression of glycoconjugates occurs during malignant transformation of cancer cells.Overexpression of sialoglycoconjugates in particular may play an important role in the progression,i.e.,invasion or metastasis,of cancer.Various types of sialoglycoconjugates have been investigated to clarify their biological significance and clinical utility in diagnosing and treating colorectal cancer.This review focuses specifically on expression of mucin(MUC)1 and it suggests that MUC1with the specific structure of a sialo-oligosaccharide has biological significance in determining the metastatic potential of colorectal cancer cells and clinicopathological utility in evaluating the effectiveness of treatments and the prognosis for patients with colorectal cancer.Further studies are expected to contribute to the expanded use of cancer-associated sialoglycoconjugates in cancer diagnosis and therapy.
文摘Aim： To study the effect of piperine on the epididymal antioxidant system of adult male rats. Methods： Adult male rats were orally administered piperine at doses of 1 mg/kg, 10 mg/kg and 100 mg/kg body weight each day for 30 consecutive days. Twenty-four hours after the last treatment, the rats were weighed and killed with ether and the epididymis was dissected from the bodies. Sperm collected from the cauda region of the epididymis was used for the assessment of its count, motility and viability. Caput, corpus and cauda regions of the epididymis were separated and homogenized separately to obtain 10 % homogenates. The supernatants were used for the assays of sialic acid, superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, lipid peroxidation and hydrogen peroxide generation. Results： Body weight of the piperine-treated rats remained unchanged. The weights of the caput, corpus and cauda regions of the epididymis significantly decreased at dose of 100 mg/kg. Epididymal sperm count and motility decreased at 10 mg/kg and 100 mg/kg, and sperm viability decreased significantly at 100 mg/kg. Sialic acid levels in the epididymis decreased significantly at 100 mg/kg while significant decrease in the cauda region alone was observed at 10 mg/kg. A significant decline in the activities of superoxide dismutase, catalase, glutathione peroxidase and glutathione reductase, along with an increase in hydrogen peroxide generation and lipid peroxidation were observed at 10 mg/kg and 100 mg/kg. Conclusion： Piperine caused a decrease in the activity of antioxidant enzymes and sialic acid levels in the epididymis and thereby increased reactive oxygen species levels that could damage the epididymal environment and sperm function.
文摘Abstract Aim: To evaluate the antifertility effect ofAlstonia scholaris bark extract in male rats. Methods: In male Wistar rats Alstonia scholaris bark extract was given by oral route at a dose of 200 mg/day for 60 days. The fertility and testicular function were assessed by mating tests, sperm motility, sperm concentration, biochemical indices and testicular cell population dynamics. Results: Oral feeding with the extract at a dose of 200 mg/day for the period of 60 days did not cause body weight loss, while the weights of testes, epididymides, seminal vesicle and ventral prostate were significantly reduced. The production of step-19 spermatids was reduced by 79.6% in treated rats. The population of preleptotene and pachytene spermatocytes were decreased by 61.9% and 60.1%, respectively. Spermatogonia and Sertoli cell population were also affected. The seminiferous tubule and Leydig cell nuclear area were reduced significantly (P<0.01) when compared to the controls. Reduced sperm count and motility resulted in a total suppression of fertility. A significant fall in the protein and sialic acid content of the testes, epididymides, seminal vesicle and ventral prostate as well as glycogen content of testes were also noticed. The fructose content in the seminal vesicle was lowered whereas the testicular cholesterol was elevated as compared with the controls. The following compounds were obtained from the extract with chromatographic separation over Si-gel column: α-amyrin, β-amyrin, lupiol acetate, venenative, rhazine and yohimbine. Conclusion: At the dose level employed, Alstonia scholaris bark extract has a significant antifertility effect in male rats; the primary site of action may be post meiotic germ cells (Step 19 spermatids).
基金the participation of the ProteinGlycan Interaction Resource of the CFG(supporting grant R24 GM098791)the National Center for Functional Glycomics(NCFG)at Beth Israel Deaconess Medical Center,Harvard Medical School(supporting grant P41 GM103694)+1 种基金supported by grants from the National Natural Science Foundation of China(NSFC)(No.21934005)National Key Research and Development Program of China(2018YFC1200602)。
文摘P[3]rotavirus(RV)has been identified in many species,including human,simian,dog,and bat.Several glycans,including sialic acid,histo-blood group antigens(HBGAs)are reported as RV attachment factors.The glycan binding specificity of different P[3]RV VP8*s were investigated in this study.Human HCR3 A and dog P[3]RV VP8*s recognized glycans with terminal sialic acid and hemagglutinated the red blood cells,while bat P[3]VP8*showed neither binding to glycans nor hemagglutination.However,the bat P[3]VP8*mutant of C189 Y obtained the ability to hemagglutinate the red blood cells,while human P[3]HCR3 A/M2-102 mutants of Y189 C lost the ability.Sequence alignment and structural analysis indicated that residue 189 played an important role in the ligand recognition and may contribute to the cross-species transmission.Structural superimposition exhibited that bat P[3]VP8*model was quite different from the simian P[3]Rhesus rotavirus(RRV)P[3]VP8*,indicating that bat P[3]RV was relatively distinct and partially contributed to the no binding to tested glycans.These results promote our understanding of P[3]VP8*/glycans interactions and the potential transmission of bat/human P[3]RVs,offering more insight into the RV infection and prevalence.
文摘In the glomeruli,mesangial cells produce mesangial matrix while podocytes wrap glomerular capillaries with cellular extensions named foot processes and tether the glomerular basement membrane(GBM).The turnover of the mature GBM and the ability of adult podocytes to repair injured GBM are unclear.The actin cytoskeleton is a major cytoplasmic component of podocyte foot processes and links the cell to the GBM.Predominant components of the normal glomerular extracellular matrix(ECM)include glycosaminoglycans,proteoglycans,laminins,fibronectin-1,and several types of collagen.In patients with diabetes,multiorgan composition of extracellular tissues is anomalous,including the kidney,so that the constitution and arrangement of glomerular ECM is profoundly altered.In patients with diabetic kidney disease(DKD),the global quantity of glomerular ECM is increased.The level of sulfated proteoglycans is reduced while hyaluronic acid is augmented,compared to control subjects.The concentration of mesangial fibronectin-1 varies depending on the stage of DKD.Mesangial type III collagen is abundant in patients with DKD,unlike normal kidneys.The amount of type V and type VI collagens is higher in DKD and increases with the progression of the disease.The GBM contains lower amount of type IV collagen in DKD compared to normal tissue.Further,genetic variants in theα3 chain of type IV collagen may modulate susceptibility to DKD and end-stage kidney disease.Human cellular models of glomerular cells,analyses of human glomerular proteome,and improved microscopy procedures have been developed to investigate the molecular composition and organization of the human glomerular ECM.
基金funded by the International Collaboration Fund(IF0119A1053)provided by the Ministry of Energy,Science,Technology,Environment and Climate Change(MESTECC),Malaysiathe Fundamental Research Grant Scheme(FRGS/1/2019/WAB01/UKM/02/1)provided by Ministry of Higher Education Malaysia。
文摘E dible bird’s nest(EBN)hydrolysates have been proven to exhibit enhanced bioactivities.However,being a macromolecule,fractions with different molecular weights would have different properties and bioactivities.Hence,this research was aimed to determine the chemical properties and antioxidant activities of freezedried(EBN_(FD))and spray-dried EBN(EBN_(SD))hydrolysates fractionated using gel permeation chromatography(GPC).Overall,two well-separated fractions were identified(EBN_(fFD1),EBN_(fFD2),EBN_(fSD1) and EBN_(fSD2)).EBNFD demonstrated significantly higher(P≤0.05)peptide(3.6%),total carbohydrate(27.7%)and sialic acid(18.2%)contents than that of EBNSD.Similar trend was observed in low molecular weight fractionates(EBN_(fFD2) and EBN_(fSD2)).Meanwhile,the first fractionates(EBN_(fFD1) and EBN_(fSD1))exhibited significantly higher(P≤0.05)hydroxyl radical(·OH)scavenging activity.Fourier transform infrared(FTIR)spectroscopy demonstrated that all EBN fractionates have similar spectrum,except in the region of N—H(amideⅡ)and C—H alkyl group.In conclusion,EBN fractionates with different molecular weights showed different chemical properties and antioxidant activities.
文摘Increasing evidence indicates that sialic acid plays an important role during nerve regeneration. Sialic acids can be modified in vitro as well as in vivo using metabolic oligosaccharide engineering of the N-awl side chain. N-Propionylmannosamine （ManNProp） increases neurite outgrowth and accelerates the reestablishment of functional synapses in vitro. We investigated the influence of systemic ManNProp application using a specific in vivo mouse model. Using mice expressing axonal fluorescent proteins, we quantified the extension of regenerating axons, the number of regenerating axons, the number of arborising axons and the number of branches per axon 5 days after injury. Sciatic nerves from non-expressing mice were grafted into those expressing yellow fluorescent protein. We began a twice-daily intraperitoneal application of either peracetylated ManNProp （200 mg/kg） or saline solution 5 days before injury, and continued it until nerve harvest （5 days after transection）. ManNProp significantly increased the mean distance of axonal regeneration （2.49 mm vs. 1.53 mm; P 〈 0.005） and the number of arborizing axons （21% vs. 16%; P = 0.008） 5 days after sciatic nerve grafting. ManNProp did not affect the number of regenerating axons or the number of branches per arborizing axon. The biochemical glycoengineering of the N-acyl side chain of sialic acid might be a promising approach for improving peripheral nerve regeneration.
文摘Aim: To evaluate the effect of aqueous Carica papaya seed extract on microenvironment of cauda epididymis.Methods: Adult male albino rats were intramuscularly administered with 0 (control) or 0.5 mg papaya seed ex-tract/kg body weight for 7 days. Cauda epididymal tubular content was collected by micropuncture technique; epididy-mal luminal fluid and sperm pellets were separately analyzed. Results: The results revealed that the extract treat-ment caused significant reduction, as compared with control, in total protein and sialic acid contents in both epididymalfluid and sperm pellet. As compared with control, significantly lowered acid phosphatase activity was recorded in spermpellet but was higher in epididymal fluid after the treatment. The extract treatment also caused significant reduction inlevel of inorganic phosphorus in the epididymal fluid. Conclusion: It is concluded that the aqueous papaya seed ex-tract alters cauda epididymal microenvironment.
基金Science Foundation of Shanghai Higher Education (Grant No.97A49)
文摘Lipid peroxide (LPO) plays pivotal roles in the process and development of many diseases. In this work, we studied the inhibitory effect of probimane (Pro), a Chinese anticancer agent, on erythrocyte LPO and the interaction of Pro with sialic acids (sia). Malondialdehyde (MDA) of erythrocytes activated by hydrogen peroxide was measured. Pro was found to inhibit the product of LPO induced by hydrogen peroxide in a non-enzyme system of both rabbit and human erythrocytes in the absence of doxorubicin. Sia were found to enhance LPO production and the activity of N-glycolylneuraminic acid (NeuGc) was about 5 times higher than that of N-acetylneuraminic acid (5AcNeu) at equivalent concentrations. Pro inhibited the increased LPO production induced by sia and the activity of Pro against LPO with 5AcNeu was almost twofold higher than that of Pro alone. It suggests that Pro be an inhibitor of LPO (free radicals) and as a functional modulator of sia in body.
