151
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Renneberg B, Li YM, Laatsch H, Fiebig HH. A short and efficient transformation of rhamnose into activated daunosamine, acosamine, ristosamine and epi-daunosamine derivatives, and synthesis of an anthracycline antibiotic acosaminyl-epsilon-iso-rhodomycinone. Carbohydr Res 2000; 329:861-72. [PMID: 11125829 DOI: 10.1016/s0008-6215(00)00257-3] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
3-Amino-2,3,6-trideoxyhexopyranoses are essential constituents of most anthracycline antitumour antibiotics. For an investigation of structure-activity relationships, the four diastereomeric amino sugars daunosamine, acosamine, ristosamine, and epi-daunosamine were synthesised in short and efficient routes starting from commercially available rhamnose. Several glycosyl donors were provided and their use was exemplified in the synthesis of acosaminyl-epsilon-isorhodomycinone.
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Affiliation(s)
- B Renneberg
- Institute of Organic Chemistry, University of Göttingen, Germany
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152
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Li YM, Han ZH, Jiang SH, Jiang Y, Yao SD, Zhu DY. Fast repairing of oxidized OH radical adducts of dAMP and dGMP by phenylpropanoid glycosides from Scrophularia ningpoensis Hemsl. Acta Pharmacol Sin 2000; 21:1125-8. [PMID: 11603287] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2023] Open
Abstract
AIM To investigate the antioxidative activity of the constituents of the roots of Scrophularia ningpoensis (Chinese name: Xuanshen). METHODS The main compounds from the roots of Scrophularia ningpoensis were isolated and identified by chromatography and FABMS, NMR etc. Using the techniques of pulse radiolysis, the electron transfers from iridoid glycosides (IG) or phenylpropanoid glycosides (PG) to oxidized OH radical adducts of 2'-deoxyadenosine-5'-monophosphate acid (dAMP) or 2'-deoxyguanosine-5'-monophosphate acid (dGMP) were observed. RESULTS Two IG: harpagoside and harpagide, two PG: angoroside C and acteoside were obtained as the main hydrophilic constituents of the plant. At 0.1 mmol/L concentration, angoroside C and acteoside were able to repair the oxidized OH adducts dAMP and dGMP significantly. However, harpagoside and harpagide had no such effect. The electron transfer rate constants of angoroside C with dAMP and dGMP were 4.2 x 10(8) and 10.3 x 10(8) L.mol-1.s-1; the electron transfer rate constants of acteoside with dAMP and dGMP were 5.3 x 10(8) and 20.2 x 10(8) L.mol-1.s-1. CONCLUSION PG from Scrophularia ningpoensis have a potent antioxidative activity for reducing of the oxidized OH adducts of dAMP and dGMP.
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Affiliation(s)
- Y M Li
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
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153
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Li YM. Chinese herbs and urothelial carcinoma. N Engl J Med 2000; 343:1269; author reply 1269-70. [PMID: 11183354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
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154
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Abstract
Three phenylpropanoid glycosides named ningposides A (3-O-acetyl-2-O-feruloyl-alpha-L-rhamnopyranose), B (4-O-acetyl-2-O-feruloyl-alpha-L-rhamnopyranose) and C (3-O-acetyl-2-O-p-hydroxycinnamoyl-alpha-L-rhamnopyranose) along with the known compounds sibirioside A, cistanoside D, angoroside C, acteoside, decaffeoylacteoside and cistanoside F were obtained from the roots of Scrophularia ningpoensis.
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Affiliation(s)
- Y M Li
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, People's Republic of China
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155
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Li YM, Xu M, Lai MT, Huang Q, Castro JL, DiMuzio-Mower J, Harrison T, Lellis C, Nadin A, Neduvelil JG, Register RB, Sardana MK, Shearman MS, Smith AL, Shi XP, Yin KC, Shafer JA, Gardell SJ. Photoactivated gamma-secretase inhibitors directed to the active site covalently label presenilin 1. Nature 2000; 405:689-94. [PMID: 10864326 DOI: 10.1038/35015085] [Citation(s) in RCA: 760] [Impact Index Per Article: 31.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Cleavage of amyloid precursor protein (APP) by the beta- and gamma-secretases generates the amino and carboxy termini, respectively, of the A beta amyloidogenic peptides A beta40 and A beta42--the major constituents of the amyloid plaques in the brain parenchyma of Alzheimer's disease patients. There is evidence that the polytopic membrane-spanning proteins, presenilin 1 and 2 (PS1 and PS2), are important determinants of gamma-secretase activity: mutations in PS1 and PS2 that are associated with early-onset familial Alzheimer's disease increase the production of A beta42 (refs 4-6), the more amyloidogenic peptide; gamma-secretase activity is reduced in neuronal cultures derived from PS1-deficient mouse embryos; and directed mutagenesis of two conserved aspartates in transmembrane segments of PS1 inactivates the ability of gamma-secretase to catalyse processing of APP within its transmembrane domain. It is unknown, however, whether PS1 (which has little or no homology to any known aspartyl protease) is itself a transmembrane aspartyl protease or a gamma-secretase cofactor, or helps to colocalize gamma-secretase and APP. Here we report photoaffinity labelling of PS1 (and PS2) by potent gamma-secretase inhibitors that were designed to function as transition state analogue inhibitors directed to the active site of an aspartyl protease. This observation indicates that PS1 (and PS2) may contain the active site of gamma-secretase. Interestingly, the intact, single-chain form of wild-type PS1 is not labelled by an active-site-directed photoaffinity probe, suggesting that intact wild-type PS1 may be an aspartyl protease zymogen.
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Affiliation(s)
- Y M Li
- Department of Biological Chemistry, Merck Research Laboratories, West Point, Pennsylvania 19486, USA.
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156
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Chen YX, Yang LW, Li YM, Zhou ZY, Lam KH, Chan AS, Kwong HL. Synthesis of a new chiral ligand, 6, 6'-dihydroxy-5, 5'-biquinoline (BIQOL) and its applications in the asymmetric addition of diethylzinc to aldehydes. Chirality 2000; 12:510-3. [PMID: 10824179 DOI: 10.1002/(sici)1520-636x(2000)12:5/6<510::aid-chir37>3.0.co;2-e] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
A new chiral ligand 6, 6'-dihydroxy-5, 5'-biquinoline (BIQOL, 2) was prepared via Cu2+ mediated coupling. The resolution was carried out by separating the corresponding ditrifluomethanesulfonate on chiral column. When applied to the enantioselective addition of diethylzinc to aromatic aldehydes, this ligand induced the reaction with enantioselectivity equivalent to that induced by BINOL. The effects of solvent and reaction temperature on enantioselectivity were also studied.
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Affiliation(s)
- Y X Chen
- Open Laboratory of Chirotechnology and Department of Applied Biology and Chemical Technology, Hong Kong Polytechnic University, Hong Kong, China
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157
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Li YM, Lai MT, Xu M, Huang Q, DiMuzio-Mower J, Sardana MK, Shi XP, Yin KC, Shafer JA, Gardell SJ. Presenilin 1 is linked with gamma-secretase activity in the detergent solubilized state. Proc Natl Acad Sci U S A 2000; 97:6138-43. [PMID: 10801983 PMCID: PMC18571 DOI: 10.1073/pnas.110126897] [Citation(s) in RCA: 439] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
gamma-Secretase is a membrane-associated protease that cleaves within the transmembrane region of amyloid precursor protein to generate the C termini of the two Abeta peptide isoforms, Abeta40 and Abeta42. Here we report the detergent solubilization and partial characterization of gamma-secretase. The activity of solubilized gamma-secretase was measured with a recombinant substrate, C100Flag, consisting largely of the C-terminal fragment of amyloid precursor protein downstream of the beta-secretase cleavage site. Cleavage of C100Flag by gamma-secretase was detected by electrochemiluminescence using antibodies that specifically recognize the Abeta40 or Abeta42 termini. Incubation of C100Flag with HeLa cell membranes or detergent-solubilized HeLa cell membranes generates both the Abeta40 and Abeta42 termini. Recovery of catalytically competent, soluble gamma-secretase critically depends on the choice of detergent; CHAPSO (3-[(3-cholamidopropyl)dimethylammonio]-2-hydroxy-1-propanesulfonate) but not Triton X-100 is suitable. Solubilized gamma-secretase activity is inhibited by pepstatin and more potently by a novel aspartyl protease transition-state analog inhibitor that blocks formation of Abeta40 and Abeta42 in mammalian cells. Upon gel exclusion chromatography, solubilized gamma-secretase activity coelutes with presenilin 1 (PS1) at an apparent relative molecular weight of approximately 2.0 x 10(6). Anti-PS1 antibody immunoprecipitates gamma-secretase activity from the solubilized gamma-secretase preparation. These data suggest that gamma-secretase activity is catalyzed by a PS1-containing macromolecular complex.
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Affiliation(s)
- Y M Li
- Department of Biological Chemistry, Merck Research Laboratories, West Point, PA 19486, USA.
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158
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Gottschalk I, Li YM, Lundahl P. Chromatography on cells: analyses of solute interactions with the glucose transporter Glut1 in human red cells adsorbed on lectin-gel beads. J Chromatogr B Biomed Sci Appl 2000; 739:55-62. [PMID: 10744313 DOI: 10.1016/s0378-4347(99)00383-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The affinities of the human red cell glucose transporter Glut1 for D-glucose and cytochalasin B (CB) and the stoichiometry of CB binding vary with the Glut1 environment. In order to study the native state of Glut1 we adsorbed human red cells to wheat germ lectin agarose gel beads for frontal affinity chromatographic analyses. Glut1 showed relatively high affinities for D-glucose (Kd 12+/-1 mM) and CB (Kd 59+/-17 nM). The number of CB-binding sites per Glut1 monomer, 0.46+/-0.16, was approximately doubled upon coating the cells with polylysine, which induced cell association.
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Affiliation(s)
- I Gottschalk
- Department of Biochemistry, Biomedical Center, Uppsala University, Sweden
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159
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Abstract
Laser manipulation of neutral atoms has been used to count individual krypton-85 and krypton-81 atoms present in a natural krypton gas sample with isotopic abundances in the range of 10(-11) and 10(-13), respectively. This method of isotope trace analysis is free of contamination from other isotopes and elements and can be applied to several different isotope tracers for a wide range of applications. The demonstrated detection efficiency is 1 x 10(-7). System improvements could increase the efficiency by many orders of magnitude.
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Affiliation(s)
- CY Chen
- Physics Division, and Chemistry Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439, USA
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160
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Li YM, Huang PS, Pai L. Blood alcohol concentration among injured drivers in Hualien County. Kaohsiung J Med Sci 1999; 15:617-24. [PMID: 10603710] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/14/2023] Open
Abstract
Vehicle-related injuries are the major cause of death and injuries in Hualien County. Driving under the influence of alcohol plays a major role in such crashes. From December 1997 to May 1998, we determined the blood alcohol concentrations of 750 injured drivers from vehicle crashes, visiting the two emergency rooms of teaching hospitals in Hualien. The objectives of this study were to investigate the incidence of alcohol used in vehicle crashes, to identify the prevalence groups for prevention and to discuss alcohol testing at emergency services. Sixty-four percent were male; 27.5% were aborigines. The mean age was 36.5 +/- 16.5 years. About 54.1% tested positive for blood alcohol concentration (BAC), which ranged from 13 to 611 mg/dL; 38.6% had BAC levels exceeding 50 mg/dL and 21.1% exceeding 200 mg/dL. The mean BAC was 85.9 mg/dL (+/- 118.5). Middle-aged males and aborigines were more likely to drive under the influence of alcohol. We recommend blood alcohol testing to be mandatory at the emergency service and to be used as evidence for prosecution in a court of law. Preventing drunk driving through community programs is imperative, especially in the aboriginal communities.
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Affiliation(s)
- Y M Li
- Department of Family Medicine, Tzu-Chi General Hospital, Hualien, Taiwan, Republic of China
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161
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Tobback K, Li YM, Pizarro NA, De Smedt I, Smeets T, Van Schepdael A, Roets E, Hoogmartens J. Micellar electrokinetic capillary chromatography of macrolide antibiotics. Separation of tylosin, erythromycin and their related substances. J Chromatogr A 1999; 857:313-20. [PMID: 10536850 DOI: 10.1016/s0021-9673(99)00770-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The separation of tylosin by micellar electrokinetic capillary chromatography with a mixed micelle system is described. Good selectivity was obtained with sodium phosphate buffer (80 mM, pH 7.5) containing 20 mM sodium cholate and 7 mM cetyltrimethylammonium bromide (CTAB). This method permits tylosin to be separated from its closely related substances within 15 min. The influences of type of buffer, buffer pH, the concentrations of sodium cholate and CTAB were investigated. The robustness of the method was examined for tylosin by means of a full-fraction factorial design. Quantitative results are presented. Using a similar buffer system (80 mM sodium phosphate, pH 6.0, 20 mM sodium cholate and 5 mM CTAB), separation of erythromycin and its main related substances was also obtained. However, detection sensitivity and resolution are not sufficient for analysis of related substances in erythromycin commercial samples.
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162
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Abstract
The development and validation of an analytical method for the determination of spiramycin I in the presence of its related substances by capillary electrophoresis is shown. The separation, performed in a phosphate buffer (80 mM, pH 7.5) containing 12 mM cetyltrimethylammonium bromide (CTAB) and 20 mM sodium cholate, with a 50 microm ID and 44 cm long fused-silica capillary (36 cm effective length), applying a voltage of 12 kV (l approximately 80 microA), at 25 degrees C, is achieved in 15 min. Good selectivity among spiramycin I and its related substances was obtained. The influence of the buffer pH, and of the CTAB and sodium cholate concentrations was investigated. The method robustness, examined by means of a full-fraction factorial design, shows that it can be used within the limits set for the three parameters that were investigated. The method is linear (r = 0.9992) and precise (day-to-day corrected peak area repeatability, n = 18, relative standard deviation = 1.3%). The limits of detection and quantitation are 7 pg (0.025%) and 22 pg (0.08%), respectively, relative to a 2 mg/mL solution.
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163
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Jenkins DJ, Kendall CW, Vuksan V, Augustin LS, Li YM, Lee B, Mehling CC, Parker T, Faulkner D, Seyler H, Vidgen E, Fulgoni V. The effect of wheat bran particle size on laxation and colonic fermentation. J Am Coll Nutr 1999; 18:339-45. [PMID: 12038477 DOI: 10.1080/07315724.1999.10718873] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
OBJECTIVE Due to perceived inferior fecal bulking ability, finely ground wheat bran is not recommended for treatment of colonic disorders, despite possible short chain fatty acid generation with potential benefits for colonic mucosal health. We therefore tested the effects of very fine particle size wheat bran on colonic function. METHODS Two studies, each with three phases, were undertaken in healthy subjects in a randomized crossover design. In one study (metabolic, n=23) subjects took three diets containing either an additional 19 g/d dietary fiber with mean particle size (MPS) 50 microm or 758 microm in bread or a control low fiber bread. In the other study where the supplement was provided as a breakfast cereal (ad libitum, n=24) the respective wheat bran MPS were 692 microm and 1158 microm and the control was low fiber. Fecal collections were obtained during the last week of each diet. In the metabolic study, fecal short chain fatty acids were measured and 12-hour breath gas collections obtained. RESULTS In both studies, wheat bran supplements significantly increased fecal bulk compared to the control (p<0.004), with no significant differences between brans of different particle size and no differences in fecal water content. However, higher fecal butyrate concentrations (p<0.007), butyrate output and breath CH4 levels (p=0.025) were seen on the low MPS wheat bran compared to the other two treatments, suggesting increased bacterial fermentation. CONCLUSIONS Fine MPS wheat bran is an effective fecal bulking agent and may have added advantages if increased butyrate concentrations promote colonic mucosal integrity.
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Affiliation(s)
- D J Jenkins
- Clinical Nutrition and Risk Factor Modification Center, St. Michael's Hospital, Toronto, Ontario, Canada
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164
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Abstract
Two new phenolic glucosides, a new gamma-lactone glucoside, and adenosine were isolated from the sprouts of CROCUS SATIVUS L. The new compounds were characterized as 2,4- dihydroxy-6-methoxyacetophenone-2beta-D-glucopyranoside, 2,3,4-trihydroxy-6-methoxyacetopenone-3-beta-D-glucopyranoside and 3-( S)-3-beta-D-glucopyranosyloxybutanolide, respectively. All structures were elucidated on the basis of chemical and spectroscopic evidence.
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Affiliation(s)
- W Y Gao
- State Key Laboratory of New Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Science, Shanghai, China
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165
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Abstract
It was first reported in China that injection of a low dose of D-galactose into mice could induce changes which resembled accelerated aging. The aging model shows neurological impairment, decreased activity of anti-oxidant enzymes, and poor immune responses. However, the underlining mechanism remains largely unknown. D-galactose is a reducing sugar that can form advanced glycation endproducts (AGE) in vivo. To investigate the role of AGE in this aging model, a group of 5-month-old C57 mice were injected daily with D-galactose, D-galactose modified AGE-lysine (AGE-lysine), L-glucose, L-lysine, or control buffer for 8 weeks. Two additional groups were treated with the AGE formation inhibitor, aminoguanidine. The results show that D-galactose, L-glucose, and AGE-lysine treated mice had a significant increase in serum AGE levels, memory latency time and error rate, and skin hydroxyproline content. Similar to aged controls, these mice also had a significant decrease in motor activity, lymphocyte mitogenesis, interleukin-2 (IL-2) production, and superoxide dismutase (SOD) enzyme activity. The aminoguanidine treated D-galactose-injected mice, however, showed no significant changes in these parameters in comparison with young controls. These data indicate that D-galactose and L-glucose form AGEs in vivo and that elevated AGEs may accelerate the aging process. The fact that both D-galactose and AGE treated mice resemble aged mice suggests that advanced glycation, at least partially, accounts for the mechanism of this aging model.
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Affiliation(s)
- X Song
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences, Beijing, People's Republic of China
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166
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Lin WL, He XB, Svensson K, Adam G, Li YM, Tang TW, Paldi A, Pfeifer S, Ohlsson R. The genotype and epigenotype synergize to diversify the spatial pattern of expression of the imprinted H19 gene. Mech Dev 1999; 82:195-7. [PMID: 10354485 DOI: 10.1016/s0925-4773(99)00009-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Little is known of how the genetic background effects the phenomenon of genomic imprinting. The H19 gene belongs to a cluster of imprinted genes on human chromosome 11. Here we show that the alternative splicing of a human H19 transcript is genotype-specific. Moreover, this variant transcript, which lacks exon 4, is either not found at all, is widely expressed or is confined to extra-villous cytotrophoblasts in first trimester placenta, depending on a combination of the genotype and the sex of the transmitting parent.
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Affiliation(s)
- W L Lin
- Department of Animal Development and Genetics, Uppsala University, Norbyvagen 18A, S-752 36, Uppsala, Sweden
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167
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Li YM, Broome JD. Arsenic targets tubulins to induce apoptosis in myeloid leukemia cells. Cancer Res 1999; 59:776-80. [PMID: 10029061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
Abstract
Arsenic exhibits a differential toxicity to cancer cells. At a high concentration (>5 microM), As2O3 causes acute necrosis in various cell lines. At a lower concentration (0.5-5 microm), it induces myeloid cell maturation and an arrest in metaphase, leading to apoptosis. As2O3-treated cells have features found with both tubulin-assembling enhancers (Taxol) and inhibitors (colchicine). Prior treatment of monomeric tubulin with As2O3 markedly inhibits GTP-induced polymerization and microtubule formation in vitro but does not destabilize GTP-induced tubulin polymers. Cross-inhibition experiments indicate that As2O3 is a noncompetitive inhibitor of GTP binding to tubulin. These observations correlate with the three-dimensional structure of beta-tubulin and suggest that the cross-linking of two vicinal cysteine residues (Cys-12 and Cys-213) by trivalent arsenic inactivates the GTP binding site. Furthermore, exogenous GTP can prevent As2O3-induced mitotic arrest.
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Affiliation(s)
- Y M Li
- Department of Laboratories, North Shore University Hospital, Manhasset, New York 11030, USA.
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168
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Abstract
A method was developed for the preparation of continuous beds derivatized with polyethyleneimine (PEI) for chromatofocusing and anion exchange chromatography in the capillary mode. First, a continuous bed activated by epoxy groups was synthesized inside a fused silica capillary and became at the same time covalently attached to the inner wall of the capillary. A PEI solution was then pumped through the continuous bed to allow the imine groups in PEI to react with the epoxy groups in the bed. Efficient immobilization of PEI was indicated by the high-resolution separation of standard proteins (hemoglobins C, S, F, and A) in both chromatofocusing and anion exchange chromatography on a capillary column prepared by this method.
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Affiliation(s)
- Y M Li
- Biomedical Center, University of Uppsala, Uppsala, S-751 23, Sweden
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169
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Abstract
Micellar electrokinetic capillary chromatography (MEKC) was examined for analysis of cefalexin and its related substances. Good selectivity was obtained with two different buffer solutions: a sodium acetate buffer (50 mM, pH 5.25) containing sodium dodecyl sulfate (50 mM SDS) or sodium phosphate buffer (40 mM, pH 7.0) containing 100 mM SDS. Both methods permit cefalexin to be completely separated from its ten related substances within 20 min. The robustness of the method, using pH 5.25 acetate buffer, was examined by means of a full-fraction factorial design to test the influence of buffer pH, concentration of SDS and buffer concentration. The parameters for validation such as linearity, precision, limit of detection and limit of quantitation are also reported. The results show that method 1 is suitable for the analysis of cefalexin.
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Affiliation(s)
- Y M Li
- Laboratorium voor Farmaceutische Chemie en Analyse van Geneesmiddelen, Faculteit Farmaceutische Wetenschappen, K. U. Leuven, Belgium
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170
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Li YM, Vanderghinste D, Pecanac D, Van Schepdael A, Roets E, Hoogmartens J. Analysis of cefadroxil by micellar electrokinetic capillary chromatography: development and validation. Electrophoresis 1998; 19:2890-4. [PMID: 9870384 DOI: 10.1002/elps.1150191615] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
A method is developed and validated for analysis of the antibiotic cefadroxil using micellar electrokinetic capillary chromatography. It permits cefadroxil to be completely separated from ten of its known related substances within 15 min (including the washing procedure). The separation is performed in an acetate buffer (50 mM, pH 5.25) containing sodium dodecyl sulfate (SDS; 110 mM). The fused-silica capillary was 44 cm long (36 cm effective length), 50 microm ID; the voltage, 18 kV; temperature, 15 degrees C; and the detection wavelength; 254 nm. The influence of the type of buffer, buffer pH and concentration, and of the SDS concentration was investigated. The robustness of the method was examined by means of a full-fraction factorial design. The parameters for validation such as linearity, precision, limit of detection and limit of quantitation are also reported.
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Affiliation(s)
- Y M Li
- Laboratorium voor Farmaceutische Chemie en Analyse van Geneesmiddelen, Faculteit Farmaceutische Wetenschappen, K.U. Leuven, Belgium
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171
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Li YM, Franklin G, Cui HM, Svensson K, He XB, Adam G, Ohlsson R, Pfeifer S. The H19 transcript is associated with polysomes and may regulate IGF2 expression in trans. J Biol Chem 1998; 273:28247-52. [PMID: 9774446 DOI: 10.1074/jbc.273.43.28247] [Citation(s) in RCA: 93] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The imprinted H19 gene produces a fully processed transcript that does not exhibit any conserved open reading frame between mouse and man. Although transcriptional control elements associated with the mouse H19 locus have been shown to control the neighboring Igf2 gene in cis, the prevailing view is that the cytoplasmic H19 transcript does not display any function. In contrast to earlier reports, we show here that the H19 transcript is associated with polysomes in a variety of cell types, in both mouse and man. A possible trans-function of the H19 gene is suggested by a reciprocal correlation in trans between cytoplasmic H19 and IGF2 mRNA levels, as well as IGF2 mRNA translatability. We discuss these results in terms of their challenge to the prevailing dogma on the function of the enigmatic H19 gene, as well as with respect to the ontogeny of the Beckwith-Wiedemann syndrome, and propose that the human H19 gene is an antagonist of IGF2 expressivity in trans.
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Affiliation(s)
- Y M Li
- Department of Animal Development & Genetics, Uppsala University, Norbyvägen 18A, S-752 36 Uppsala, Sweden
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172
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Abstract
Lactoferrin and lysozyme are two important, naturally occurring antibacterial proteins found in saliva, nasal secretions, milk, mucus, serum and in the lysosomes of neutrophils and macrophages. Both proteins bind specifically to glucose-modified proteins bearing advanced glycation endproducts (AGEs). Exposure to AGE-modified proteins blocks the bacterial agglutination and bacterial killing activities of lactoferrin and also inhibits the bactericidal and enzymatic activity of lysozyme. Peptide mapping by AGE ligand blot revealed two AGE-binding domains in lactoferrin, and a single AGE-binding domain in lysozyme. None of these AGE-binding domains displayed any significant homology in their primary sequences; however, a common 17-18 amino acid cysteine loop motif (CX15-16C) was identified among them, which we named an ABCD motif (AGE-Binding Cysteine-bounded Domain). Similar domains are also present in other antimicrobial proteins such as defesins. Hydrophilicity analysis indicated that each of these ABCD loops is markedly hydrophilic. Synthetic peptides, corresponding to these motifs in lactoferrin and lysozyme, exhibited AGE-binding activity. Since diabetes is associated with abnormally high levels of tissue and serum AGEs, the elevated AGEs may inhibit endogenous antibacterial proteins by binding to the conserved ABCD motif, thereby increasing susceptibility to bacterial infections in diabetic individuals. These results may provide a basis for the development of new approaches to prevent diabetic infections.
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Affiliation(s)
- Y M Li
- Picower Institute for Medical Research, Manhasset, New York 11030, USA
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173
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Li YM, Yen LL. Self-rated psychiatric symptoms and their correlates among senior high school students in Hualien City. J Formos Med Assoc 1998; 97:593-9. [PMID: 9795526] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
The association between mental health disorders beginning in adolescence and disorders in early adulthood is increasingly acknowledged. The mental health of adolescents has not been studied in the eastern area of Taiwan, where the mortality of teenagers is highest in Taiwan. The purpose of this study was to assess psychiatric symptoms among senior high school students in Hualien City, and to identify their associated factors. A total of 1,195 students were selected, via a stratified cluster sampling method, from nine high schools in Hualien City. A self-administered questionnaire was used to assess students' demographic characteristics, neurotic traits, perceived daily-life stress, social support, and psychiatric symptoms. There were 1,141 valid responses. From principal components analysis, depression-anxiety, impulsivity-paranoia, and psychoticism-obsession were found to be the most common self-rated psychiatric symptoms. About 70% of the students felt blue, 48.2% reported urges to injure someone, and 25% felt tense. Overall, about 5% to 10% of high school students had severe psychiatric symptoms. Stress from schoolwork, peer relationships, and neurotic traits were important predictors of psychiatric symptoms. The findings of this study imply that screening for psychiatric symptoms at senior high schools is essential for improving the mental health of students. The mental health care of adolescents should be school-based and in collaboration with medical professionals. Life skills must be taught at school.
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Affiliation(s)
- Y M Li
- Department of Family Medicine, Tzu-Chi General Hospital, Hualien, Taiwan
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174
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Affiliation(s)
- S Hjertén
- Department of Biochemistry, Uppsala University, Sweden
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175
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Li YM, Yen LL. Daily life stress and its correlates among high school students in Hualien city. Kaohsiung J Med Sci 1998; 14:234-41. [PMID: 9589618] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Adolescence is a period of physical, cognitive, social and psychosexual changes. These developmental tasks make adolescents particularly vulnerable to life stress. The purpose of this study was to assess high school students' perception of stress from daily events and to identify its associated factors. A total of 1,195 high school students were selected via stratified cluster sampling method from nine high schools. Data from 1,141 valid answers were analyzed. A self-administrated questionnaire was used to assess students' demographic characteristics, personal traits (self-acceptance, neurotic trait), social support and perceived daily life stress. From principal component analysis, school work, concern with prospects, parent-teen relationship and peer relationship were found to be the main sources of daily life stress perceived. Personalities with high neurotic trait or low self-acceptance, perceived low social support, Chinese Hans and study at regular high school were important related factors. Screening by personality trait and social support questionnaire is suggested to be a routine at school to find out the high risk individuals and give them assistance in coping with stress.
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Affiliation(s)
- Y M Li
- Department of Family Medicine, Tzu-Chi General Hospital, Hualien, Taiwan, Republic of China
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176
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Abstract
Dynorphins and beta-endorphin in human plasma were characterized and studied quantitatively using radioimmunoassay, high-performance liquid chromatography (HPLC), and mass spectrometry. Most immunoreactive (ir) dynorphin B and beta-endorphin in human plasma coeluted with authentic peptides in analysis. Dynorphin A was not detected. Added to human plasma it was rapidly converted into Leu-enkephalin-Arg6 followed by elimination of the C-terminal arginine after prolonged incubation. The rate of dynorphin A conversion was estimated at 40 pmol/min/microl plasma. This process was inhibited by the thiol protease inhibitor, PHMB and by EDTA. Dynorphin B, alpha-neoendorphin and big dynorphin were virtually not metabolized by plasma proteases under the same conditions. beta-endorphin was processed into beta-endorphin(1-19) and the corresponding C-terminal counterpart beta-endorphin(20-31) at a rate of about 25 pmol/min/microl of plasma. Based on the above data, a reliable strategy was established to measure dynorphin B- and beta-endorphin-ir in human plasma samples. The basal levels in a male control group were 0.99 +/- 0.11 (n = 11) and 16.3 +/- 1.5 (n = 11) fmol/ml plasma, respectively.
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Affiliation(s)
- J Silberring
- Faculty of Chemistry, Jagiellonian University, Krakow, Poland
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177
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Abstract
Sixty percent of patients with human immunodeficiency virus (HIV) in the United States and 90% throughout the world will have diarrhea at some point in their illness. This article provides an introductory exploration and discussion of Western and Eastern perspectives of chronic diarrhea in patients with HIV. Western etiologies and treatment approaches, as well as Eastern views from traditional Chinese medicine pathogenesis and treatment principles involving acupuncture and moxibustion are presented. Whereas their interpretations of the causes of diarrhea are different, both the East and West have something to offer patients with this distressing symptom. Further exploration and clinical research is needed in this area.
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Affiliation(s)
- J K Anastasi
- Center for AIDS Research, Columbia University School of Nursing, New York, NY, USA
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178
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Zhu XY, Fang HQ, Zeng SP, Li YM, Lin HL, Shi SZ. The impact of the neonatal resuscitation program guidelines (NRPG) on the neonatal mortality in a hospital in Zhuhai, China. Singapore Med J 1997; 38:485-7. [PMID: 9550910] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
AIM The neonatal resuscitation program (NRPG) was first introduced in our hospital to replace the traditional resuscitation (TR) program in 1993. TR has been in existence in China for a long time. The implementation of NRPG was timely in reducing the number of infant mortality and also to disseminate to the many hospitals in China which are still practising TR. METHOD A perspective study of 4,751 newborns with 366 asphyxiated babies in a period of 2 years was carried out. A previous sample of 1,722 live births under the TR program was compared as a controlled group statistically. RESULTS From August 1993 to August 1995, when NRPG was exclusively implemented in our hospital, only 16 newborns died within 7 days, out of 4,751 births (3.4%) with 2 deaths in the delivery room. Seventeen newborns died within 7 days out of 1,722 births (9.9+) in the TR group, with 10 deaths in the delivery room. From the data shown, it can be clearly seen that perinatal neonatal mortality rate was reduced almost 3 times after NRPG was implemented (chi(2) = 10.54, p < 0.01). The follow-up results of 21 cases of severe asphyxia at 2 months--1 year of age were normal except for one with cerebral palsy. CONCLUSIONS Our study showed that NRPG was indeed a very effective and feasible technique during the delivery process in the reduction of neonatal mortality. It is important to disseminate widely the knowledge and technique of NRPG in places where TR is still being widely practiced especially in developing countries.
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Affiliation(s)
- X Y Zhu
- Department of Neonatal Medicine Maternal and Child Health Hospital, Zhuhai City, Guangdong, China
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179
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Stitt AW, He C, Friedman S, Scher L, Rossi P, Ong L, Founds H, Li YM, Bucala R, Vlassara H. Elevated AGE-modified ApoB in sera of euglycemic, normolipidemic patients with atherosclerosis: relationship to tissue AGEs. Mol Med 1997; 3:617-27. [PMID: 9323713 PMCID: PMC2230092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
BACKGROUND Advanced glycation endproducts (AGEs) are implicated in the pathogenesis of atherosclerotic vascular disease of diabetic and nondiabetic etiology. Recent research suggests that advanced glycation of ApoB contributes to the development of hyperlipidemia. AGE-specific receptors, expressed on vascular endothelium and mononuclear cells, may be involved in both the clearance of, and the inflammatory responses to AGEs. The aim of this study was to examine whether there is a relationship between serum AGE-ApoB and AGEs in arterial tissue of older normolipidemic nondiabetic patients with occlusive atherosclerotic disease, compared with age-matched and younger asymptomatic persons. MATERIALS AND METHODS Serum AGE-ApoB was measured by ELISA in 21 cardiac bypass patients. Furthermore, an AGE-specific monoclonal antibody, and polyclonal antibodies against anti-AGE-receptor (anti-AGE-R) 1 and 2 were used to explore the localization and distribution of AGEs and AGE-R immunoreactivity (IR) in arterial segments excised from these patients. RESULTS Serum AGE-ApoB levels were significantly elevated in the asymptomatic, older population, compared with those in young healthy persons (259 +/- 24 versus 180 +/- 21 AGE U/mg of ApoB, p < 0.01). Higher AGE-ApoB levels were observed in those patients with atherosclerosis (329 +/- 23 versus 259 +/- 24 AGE U/mg ApoB, p < 0.05). Comparisons of tissue AGE-collagen with serum AGE-ApoB levels showed a significant correlation (r = 0.707, p < 0.01). In early lesions, AGE-IR occurred mostly extracellularly. In fatty streaks and dense, cellular atheromatous lesions, AGE-IR was visible within lipid-containing smooth muscle cells and macrophages, while in late-stage, acellular plaques, AGE-IR occurred mostly extracellularly. AGE-R1 and -R2 were observed on vascular endothelial and smooth-muscle cells and on infiltrating mononuclear cells in the early-stage lesions, whereas in dense, late-stage plaques, they colocalized mostly with lipid-laden macrophages. On tissue sections, scoring of AGE-immunofluorescence correlated with tissue AGE and plasma AGE-ApoB. CONCLUSIONS (1) The correlation between arterial tissue AGEs and circulating AGE-ApoB suggests a causal link between AGE modification of lipoproteins and atherosclerosis. AGE-specific receptors may contribute to this process. (2) Serum AGE-ApoB may serve to predict atherosclerosis in asymptomatic patients.
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Affiliation(s)
- A W Stitt
- Picower Institute for Medical Research, Manhasset, New York, USA
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180
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Mitsuhashi T, Vlassara H, Founds HW, Li YM. Standardizing the immunological measurement of advanced glycation endproducts using normal human serum. J Immunol Methods 1997; 207:79-88. [PMID: 9328589 DOI: 10.1016/s0022-1759(97)00110-5] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Advanced glycation endproducts (AGEs) have been linked to many sequelae of diabetes, renal disease and aging. To detect AGE levels in human tissues and blood samples, a competitive enzyme-linked immunosorbent assay (ELISA) has been widely used. As no consensus or standard research method for the quantitation of AGEs currently exists, nor a universally defined AGE unit available, the comparative quantitation of AGEs between research laboratories is problematic and restricts the usefulness of interlaboratory clinical data. By comparing the cross-reactivities of five different anti-AGE antisera with five different in vitro AGE-modified proteins, we found that the immunological recognition of AGEs by competitive ELISA is both AGE-carrier protein- and anti-AGE antibody-dependent. This suggests that in vitro AGE-modified proteins might not be appropriate standards for AGEs that occur naturally in vivo. Based on our observation that serum AGE levels in the normal human population are consistently within a narrow range and several folds lower than in diabetics, we propose a method to standardize AGE units against normal human serum (NHS). In this new method, one AGE unit is defined as the inhibition that results from 1:5 diluted NHS in the competitive AGE-ELISA; thus the AGE value in NHS is 5 units/ml. This NHS method requires a competitive AGE-ELISA with reasonable sensitivity such that 1:5 NHS produces a 25 to 40% inhibition of anti-AGE antibody binding to immobilized AGE-proteins. By using this standardized method we found that the AGE levels in normal human serum (5.0 +/- 2.2 units/ml; mean +/- SD, n = 34) fit a normal distribution (chi 2-test, p < 0.01), and the serum AGE levels in diabetic patients (20.3 +/- 3.8 units/ml, n = 7) are significantly higher than that of the normal population (p < 0.0001). Since AGE units can now be defined against a universally available standard, NHS, the results of quantitative AGE measurements using this method should be comparable between assays and between different laboratories. Taken together, standardizing the AGE-ELISA protocol as described here provides a simple and quantitative method that should facilitate the expanded application of clinical AGE data.
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Affiliation(s)
- T Mitsuhashi
- Picower Institute for Medical Research, Manhasset, NY 11030, USA
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181
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Mitsuhashi T, Li YM, Fishbane S, Vlassara H. Depletion of reactive advanced glycation endproducts from diabetic uremic sera using a lysozyme-linked matrix. J Clin Invest 1997; 100:847-54. [PMID: 9259584 PMCID: PMC508257 DOI: 10.1172/jci119600] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Diabetic uremic sera contain excessive amounts of reactive advanced glycation endproducts (AGEs), which accelerate the vasculopathy of diabetes and end-stage renal disease. To capture in vivo-derived toxic AGEs, high affinity AGE-binding protein lysozyme (LZ) was linked to a Sepharose 4B matrix. Initial studies showed that > 80% of 125I-AGE-BSA was retained by the LZ matrix, compared with < 10% retained by a control matrix. More than 60% of AGE-lysine was captured by the LZ matrix, and the LZ-bound fraction retained immunoreactivity and cross-linking activity, but had little intrinsic fluorescence (370/440 nm). After passage through the LZ matrix, AGE levels in diabetic sera (0.37+/-0.04 U/mg) were significantly reduced to a level (0.09+/-0.01 U/mg; n = 10; P < 0. 0001) comparable with the level of normal human serum, whereas total protein absorption was < 3%. The AGE-enriched serum fraction exhibited cross-linking activity, which was completely prevented by aminoguanidine. Among numerous LZ-bound proteins in diabetic uremic sera, three major proteins "susceptible" to AGE modification were identified: the immunoglobulin G light chain, apolipoprotein J (clusterin/SP-40,40), and the complement 3b beta chain. These findings indicate that the LZ-linked AGE affinity column may serve as an efficient method for the depletion of toxic AGEs from sera, including specific AGE-modified proteins that may be linked to altered immunity, lipoprotein metabolism, and accelerated vasculopathy in renal failure patients with or without diabetes.
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Affiliation(s)
- T Mitsuhashi
- The Picower Institute for Medical Research, Manhasset, New York 11030, USA
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182
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Abstract
The phytoremediation of metal-contaminated soils offers a low-cost method for soil remediation and some extracted metals may be recycled for value. Both the phytoextraction of metals and the phytovolatilization of Se or Hg by plants offer great promise for commercial development. Natural metal hyperaccumulator phenotype is much more important than high-yield ability when using plants to remove metals from contaminated soils. The hypertolerance of metals is the key plant characteristic required for hyperaccumulation; vacuolar compartmentalization appears to be the source of hypertolerance of natural hyperaccumulator plants. Alternatively, soil Pb and Cr6+ may be inactivated in the soil by plants and soil amendments (phytostabilization). Little molecular understanding of plant activities critical to phytoremediation has been achieved, but recent progress in characterizing Fe, Cd and Zn uptake by Arabidopsis and yeast mutants indicates strategies for developing transgenic improved phytoremediation cultivars for commercial use.
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Affiliation(s)
- R L Chaney
- United States Department of Agriculture, Beltsville Agricultural Research Center West, MD 20705, USA.
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183
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Li YM, Dickson DW. Enhanced binding of advanced glycation endproducts (AGE) by the ApoE4 isoform links the mechanism of plaque deposition in Alzheimer's disease. Neurosci Lett 1997; 226:155-8. [PMID: 9175590 DOI: 10.1016/s0304-3940(97)00266-8] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Alzheimer's disease (AD) brains contain high levels of advanced glycation endproducts (AGEs). Double immunostaining using anti-AGE and anti-apolipoprotein E (apoE) antibodies demonstrated that AGEs co-localized to a very high degree with apoE. We examined the binding of apoE to in vitro-prepared AGE-bovine serum albumin (AGE-BSA), using Western ligand blot analysis. ApoE exhibited AGE-specific binding activity in the presence of excess native BSA, with the dimeric form of apoE binding better than the monomeric form. Other apolipoproteins including apo A1, B, CI and CII, and serum beta2-microglobulin, did not bind AGE-BSA. ApoE4 exhibited a 3-fold greater AGE-binding activity than the apoE3 isoform. These results suggest that apoE may participate in aggregate formation in the AD brain by binding to AGE-modified plaque components. It is possible that enhanced binding of apoE4 might have pathogenic consequences in vivo.
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Affiliation(s)
- Y M Li
- The Picower Institute for Medical Research, New York, NY 11030, USA
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184
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Abstract
Optimized methods for the analysis of some tetracyclines by capillary electrophoresis are described. Different buffer systems were employed for the separation of tetracycline, oxytetracycline and demeclocycline from their respective major impurities, including the 2-acetyl-2-decarboxamido derivatives. The influence of buffer pH and buffer concentration was systematically investigated. Non-ionic surfactant Triton X-100 and methyl-beta-cyclodextrin were used to obtain improved selectivity in the case of oxytetracycline and demeclocycline. The results are compared with those of previously established liquid chromatography methods. Good correlations were obtained.
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Affiliation(s)
- Y M Li
- Laboratorium voor Farmaceutische Chemie en Analyse van Geneesmiddelen, Faculteit Farmaceutische Wetenschappen, K.U. Leuven, Belgium
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185
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Li YM, Chen KJ, Zhang XW. [Effect of xuefuzhuyu pill on patients with carotid atherosclerosis by colour Doppler ultrasonography]. Zhongguo Zhong Xi Yi Jie He Za Zhi 1997; 17:152-4. [PMID: 9863081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
OBJECTIVE To observe the effect of Xuefuzhuyu Pill (XFZYP) on carotid atherosclerosis. METHODS The patients were randomly divided into XFZYP group and aspirin control group. The status of the carotid plaque vessel wall and blood flow were observed by colored Doppler ultrasonography. RESULTS (1) Plaque of 6 cases regressed, of 6 cases unchanged, of 1 case progressed after treatment of XFZYP. The area of plaques between baseline and after treatment decreased 0.11 +/- 0.05 cm and that of thickness reduced for 0.09 +/- 0.04 cm2 (P < 0.05) in XFZYP group. While plaque of 3 cases regressed, of 6 unchanged, of 2 cases progressed after treatment of aspirin. The area and thickness of plaque were reduced to 0.05 +/- 0.04 cm and 0.04 +/- 0.03 cm respectively. There were no statistic difference in aspirin group. (2) The intima-media thickness of common carotid artery decreased 0.13 +/- 0.03 mm in XFZYP group (P < 0.001 versus baseline), but there were no significant change after treatment of aspirin (P > 0.05). (3) There were no distinct change about peak systole, minimal diastole time average peak, pulsative index, resistive index in common carotid artery and internal carotid artery after treatment of XFZYP and aspirin. CONCLUSION Colour Doppler ultrasonography of carotid artery provide a noninvasive, safe and valid opportunities for clinical trail. XFZYP can be useful for the treatment of carotid atherosclerosis.
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Affiliation(s)
- Y M Li
- Xiyuan Hospital, China Academy of Traditional Chinese Medicine, Beijing
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186
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Abstract
Thioglycollate medium (TGM) is widely used as a stimulatory agent to induce non-infectious peritoneal inflammation for elicitation of macrophages from mice and rats. It has been known for a long time that aged, autoclaved TGM is more efficient than freshly prepared TGM, however, the mechanism responsible for this enhanced activity of aged TGM remains obscure. The aging of TGM apparently favors the non-enzymatic reactions between proteins and reducing sugars in TGM that may lead to the generation of advanced glycation endproducts (AGEs). We have found that aged TGM contains 40-fold more AGEs than fresh TGM. The formation of AGEs in TGM was completely blocked by co-incubation with an AGE inhibitor, aminoguanidine. Intraperitoneal injection of aged TGM into rats elicited approximately 2-fold more macrophages than fresh TGM. However, the addition of AGE-modified proteins to fresh TGM increased the yield of peritoneal cells to a level which was significantly higher than both fresh and aged TGM. The injection of AGE-modified proteins alone did not elicit significantly more macrophages than the level of resident peritoneal cells. These results suggest that the formation of AGEs during aging of TGM is responsible for the enhanced macrophage-eliciting activity in aged TGM. AGEs may act as an enhancing agent to augment the existing inflammatory responses. AGE-supplemented TGM may provide an efficient method for eliciting peritoneal macrophages or establishing an inflammatory animal model.
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Affiliation(s)
- Y M Li
- The Picower Institute for Medical Research, Manhasset, NY 11030, USA
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187
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Stitt AW, Li YM, Gardiner TA, Bucala R, Archer DB, Vlassara H. Advanced glycation end products (AGEs) co-localize with AGE receptors in the retinal vasculature of diabetic and of AGE-infused rats. Am J Pathol 1997; 150:523-31. [PMID: 9033268 PMCID: PMC1858286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Advanced glycation end products (AGEs), formed from the nonenzymatic glycation of proteins and lipids with reducing sugars, have been implicated in many diabetic complications; however, their role in diabetic retinopathy remains largely unknown. Recent studies suggest that the cellular actions of AGEs may be mediated by AGE-specific receptors (AGE-R). We have examined the immunolocalization of AGEs and AGE-R components R1 and R2 in the retinal vasculature at 2, 4, and 8 months after STZ-induced diabetes as well as in nondiabetic rats infused with AGE bovine serum albumin for 2 weeks. Using polyclonal or monoclonal anti-AGE antibodies and polyclonal antibodies to recombinant AGE-R1 and AGE-R2, immunoreactivity (IR) was examined in the complete retinal vascular tree after isolation by trypsin digestion. After 2, 4, and 8 months of diabetes, there was a gradual increase in AGE IR in basement membrane. At 8 months, pericytes, smooth muscle cells, and endothelial cells of the retinal vessels showed dense intracellular AGE IR. AGE epitopes stained most intensely within pericytes and smooth muscle cells but less in basement membrane of AGE-infused rats compared with the diabetic group. Retinas from normal or bovine-serum-albumin-infused rats were largely negative for AGE IR. AGE-R1 and -R2 co-localized strongly with AGEs of vascular endothelial cells, pericytes, and smooth muscle cells of either normal, diabetic, or AGE-infused rat retinas, and this distribution did not vary with each condition. The data indicate that AGEs accumulate as a function of diabetes duration first within the basement membrane and then intracellularly, co-localizing with cellular AGE-Rs. Significant AGE deposits appear within the pericytes after long-term diabetes or acute challenge with AGE infusion conditions associated with pericyte damage. Co-localization of AGEs and AGE-Rs in retinal cells points to possible interactions of pathogenic significance.
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Affiliation(s)
- A W Stitt
- Picower Institute for Medical Research, Manhasset, New York 11030, USA
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188
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Li YM, Schacher DH, Liu Q, Arkins S, Rebeiz N, McCusker RH, Dantzer R, Kelley KW. Regulation of myeloid growth and differentiation by the insulin-like growth factor I receptor. Endocrinology 1997; 138:362-8. [PMID: 8977425 DOI: 10.1210/endo.138.1.4847] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Flow cytometry was used to examine the expression of type I insulin-like growth factor receptors (IGF-IR) on three types of human hematopoietic cells that represent different stages of myeloid lineage development. Both HL-60 (promyeloid) and U-937 (monocytic) cells express abundant IGF-IR protein (> 79% cells positive for the IGF-IR), whereas KG-1 myeloblasts express negligible levels of IGF-IR (< 1% IGF-IR-positive cells). Exogenous IGF-I, IGF-II, and an IGF-I analog that binds poorly to IGF-binding protein-3 (des-IGF-I) increased DNA synthesis of HL-60 and U-937 cells in a dose-dependent (1-25 ng/ml) fashion by 2- to 4-fold in serum-free medium, whereas KG-1 cells did not respond to any of these growth factors. The IGF-induced increase in proliferation of HL-60 promyeloid cells was inhibited by soluble IGF-binding protein-3 (500 ng/ml) when these cells were stimulated with 10 ng/ml of either IGF-I (53 +/- 8%) or IGF-II (59 +/- 8%), but not with des-IGF-I (3 +/- 1%). In contrast, the anti-IGF-IR monoclonal antibody (mAb; alpha IR-3) inhibited the DNA synthesis caused by 10 ng/ml exogenous IGF-I (67 +/- 6%), IGF-II (72 +/- 8%), and des-IGF-1 (82 +/- 9%). Proliferation of KG-1 myeloblasts, however, was neither stimulated by the IGFs nor inhibited by the anti-IGF-IR mAb. In the absence of exogenous IGF-I, the mAb directed against the IGF-IR significantly suppressed basal DNA synthesis of HL-60 promyeloid (72 +/- 5%) and U-937 monocytic (39 +/- 7%) cells, but did not affect DNA synthesis of KG-1 myeloblasts (8 +/- 1%) compared to an isotype-matched control mAb. Similarly, the alpha IR-3 mAb abrogated vitamin D3-induced differentiation of the HL-60 cells into macrophages in serum-free medium, as assessed by expression of the leucam surface protein, CD11b. As the alpha IR-3 mAb inhibits DNA synthesis in the presence and absence of exogenous IGF-I on receptor-bearing cells, but not IGF-IR-negative cells, these data demonstrate that both endocrine and autocrine IGF-I are potent growth factors in human myeloid cells where expression of the surface receptor, rather than the ligand, is the critical control element. More importantly, these data support the hypothesis that autocrine IGF-I may play a significant role in the differentiation of promyeloid cells into macrophages.
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Affiliation(s)
- Y M Li
- Laboratory of Immunophysiology, University of Illinois, Urbana 61801, USA
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189
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Madison LL, Vivas EI, Li YM, Walsh CT, Kolter R. The leader peptide is essential for the post-translational modification of the DNA-gyrase inhibitor microcin B17. Mol Microbiol 1997; 23:161-8. [PMID: 9004229 DOI: 10.1046/j.1365-2958.1997.2041565.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Microcin B17 (MccB17) is a ribosomally encoded DNA-gyrase inhibitor. Ribosomally encoded antibiotics are derived from precursors containing an N-terminal leader, which is removed during maturation, and a C-terminal structural peptide. PreMccB17, the translational product of mcbA, is modified into proMccB17 by the action of three enzymes, McbB, McbC, and McbD. A chromosomally encoded peptidase then converts proMccB17 into MccB17. The role of McbB, McbC, and McbD is to convert glycine, cysteine, and serine residues present in preMccB17 into four thiazole and four oxazole rings. Using a modification-specific antibody rather than antimicrobial activity, we show that the 26-amino-acid N-terminal leader of preMccB17 is essential for the conversion of preMccB17 into proMccB17. Neither a preMccB17 peptide lacking the leader nor a preMccB17-beta-galactosidase fusion lacking the leader are post-translationally modified.
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Affiliation(s)
- L L Madison
- Department of Molecular Genetics and Microbiology, Harvard Medical School, Boston, Massachusetts 02115, USA
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190
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Abstract
Esherichia coli microcin B17 is a posttranslationally modified peptide that inhibits bacterial DNA gyrase. It contains four oxazole and four thiazole rings and is representative of a broad class of pharmaceutically important natural products with five-membered heterocycles derived from peptide precursors. An in vitro assay was developed to detect heterocycle formation, and an enzyme complex, microcin B17 synthase, was purified and found to contain three proteins, McbB, McbC, and McbD, that convert 14 residues into the eight mono- and bisheterocyclic moieties in vitro that confer antibiotic activity on mature microcin B17. These enzymatic reactions alter the peptide backbone connectivity. The propeptide region of premicrocin is the major recognition determinant for binding and downstream heterocycle formation by microcin B17 synthase. A general pathway for the enzymatic biosynthesis of these heterocycles is formulated.
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Affiliation(s)
- Y M Li
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA
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191
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Zhang Y, Zeng CM, Li YM, Hjertén S, Lundahl P. Immobilized liposome chromatography of drugs on capillary continuous beds for model analysis of drug-membrane interactions. J Chromatogr A 1996; 749:13-8. [PMID: 8921592 DOI: 10.1016/0021-9673(96)00432-3] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Liposomes were immobilized in capillary continuous beds with covalently linked C4 or C8 alkyl ligands for chromatographic analysis of drug interaction with phospholipid bilayers, as reflected by drug retention volumes and calculated differences in interaction free energies. This procedure is a high-resolution micro-scale version of immobilized liposome chromatography for prediction of diffusion of drugs across biological membranes. The logarithm of the specific capacity factors of several structurally unrelated drugs showed a linear correlation with the logarithm of known apparent drug permeabilities through Caco-2 epithelial cell monolayers. The latter values are used for prediction of absorption of orally administered drug doses.
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Affiliation(s)
- Y Zhang
- Department of Biochemistry, Uppsala University, Sweden
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192
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Li YM, Mitsuhashi T, Wojciechowicz D, Shimizu N, Li J, Stitt A, He C, Banerjee D, Vlassara H. Molecular identity and cellular distribution of advanced glycation endproduct receptors: relationship of p60 to OST-48 and p90 to 80K-H membrane proteins. Proc Natl Acad Sci U S A 1996; 93:11047-52. [PMID: 8855306 PMCID: PMC38281 DOI: 10.1073/pnas.93.20.11047] [Citation(s) in RCA: 254] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Advanced glycation endproducts (AGEs) are derivatives of nonenzymatic reactions between sugars and protein or lipids, and together with AGE-specific receptors are involved in numerous pathogenic processes associated with aging and hyperglycemia. Two of the known AGE-binding proteins isolated from rat liver membranes, p60 and p90, have been partially sequenced. We now report that the N-terminal sequence of p60 exhibits 95% identity to OST-48, a 48-kDa member of the oligosaccharyltransferase complex found in microsomal membranes, while sequence analysis of p90 revealed 73% and 85% identity to the N-terminal and internal sequences, respectively, of human 80K-H, a 80- to 87-kDa protein substrate for protein kinase C. AGE-ligand and Western analyses of purified oligosaccharyltransferase complex, enriched rough endoplasmic reticulum, smooth endoplasmic reticulum, and plasma membranes from rat liver or RAW 264.7 macrophages yielded a single protein of approximately 50 kDa recognized by both anti-p60 and anti-OST-48 antibodies, and also exhibited AGE-specific binding. Immunoprecipitated OST-48 from rat rough endoplasmic reticulum fractions exhibited both AGE binding and immunoreactivity to an anti-p60 antibody. Immune IgG raised to recombinant OST-48 and 80K-H inhibited binding of AGE-bovine serum albumin to cell membranes in a dose-dependent manner. Immunostaining and flow cytometry demonstrated the surface expression of OST-48 and 80K-H on numerous cell types and tissues, including mononuclear, endothelial, renal, and brain neuronal and glial cells. We conclude that the AGE receptor components p60 and p90 are identical to OST-48, and 80K-H, respectively, and that they together contribute to the processing of AGEs from extra- and intracellular compartments and in the cellular responses associated with these pathogenic substances.
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Affiliation(s)
- Y M Li
- Picower Institute for Medical Research, Manhasset, NY 11030, USA
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193
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Li YM. [Improving language abilities of student nurses in basic nursing teaching]. Zhonghua Hu Li Za Zhi 1996; 31:600-1. [PMID: 9295542] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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194
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Essick JM, Nobel Z, Li YM, Bennett MS. Conduction- and valence-band offsets at the hydrogenated amorphous silicon-carbon/crystalline silicon interface via capacitance techniques. Phys Rev B Condens Matter 1996; 54:4885-4890. [PMID: 9986449 DOI: 10.1103/physrevb.54.4885] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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195
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Li YM, Fedosejevs R. Ionization-induced blue shift of KrF laser pulses in an underdense plasma. Phys Rev E Stat Phys Plasmas Fluids Relat Interdiscip Topics 1996; 54:2166-2169. [PMID: 9965307 DOI: 10.1103/physreve.54.2166] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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196
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Birch BD, Johnson JP, Parsa A, Desai RD, Yoon JT, Lycette CA, Li YM, Bruce JN. Frequent type 2 neurofibromatosis gene transcript mutations in sporadic intramedullary spinal cord ependymomas. Neurosurgery 1996; 39:135-40. [PMID: 8805149 DOI: 10.1097/00006123-199607000-00026] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
OBJECTIVE To further investigate the role of Type 2 neurofibromatosis (NF2) gene transcript mutations in the sporadically occurring counterparts of NF2-associated tumors. METHODS Reverse transcription-polymerase chain reaction followed by agarose gel electrophoresis, single strand conformation polymorphism analysis, and automated deoxyribonucleic acid sequence analysis were used to screen for mutations in the NF2 gene transcript in seven unrelated patients with sporadic intramedullary spinal cord ependymomas. RESULTS Five of seven intramedullary spinal cord ependymomas harbored detectable mutations. All of these mutations occurred in the region of the transcript that is homologous to known cytoskeletal proteins and resulted in significant truncation of the predicted protein product. CONCLUSION Mutations of the NF2 transcript occur in the majority of sporadic intramedullary spinal cord ependymomas. These mutations are frequent in a region of the transcript that is homologous to a family of cytoskeletal proteins, and they probably render the protein product inactive. These results add to the body of knowledge concerning the role of the NF2 gene transcript in tumorigenesis.
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Affiliation(s)
- B D Birch
- Department of Neurological Surgery, Columbia Presbyterian Medical Center, New York, New York, USA
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197
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Li YM, d'Ambrumenil N, Yu L, Su ZB. Analytical results for a hole in an antiferromagnet. Phys Rev B Condens Matter 1996; 53:R14717-R14720. [PMID: 9983338 DOI: 10.1103/physrevb.53.r14717] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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198
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Abstract
A method is described for analysis of the tetracycline antibiotic minocycline using capillary zone electrophoresis. Potential impurities are 4-epiminocycline, 6-deoxy-6-demethyltetracycline, 7-didemethylminocycline, 7-monodemethylminocycline and 9-minocycline. Method development was undertaken with a mixture consisting of minocycline and its related substances mentioned above. Using a fused silica capillary, the type of buffer and its pH and concentration were investigated. In all cases 1 mM EDTA was added to prevent metal ion complexation. Instrumental parameters such as capillary temperature and applied voltage were optimised. The effects of the sample solvent and of organic modifiers in the buffer were also investigated. The following method is proposed: capillary: fused silica, l = 38 cm, L = 44 cm, 50 microns i.d.; buffer: 25 mM sodium tetraborate, 1 mM EDTA at pH 11.75; voltage, 13 kV; temperature, 15 degrees C; UV detection performed at 254 nm. Relative standard deviations, linearity, LOD and LOQ are reported and compared with those of liquid chromatography.
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Affiliation(s)
- Y M Li
- Laboratorium voor Farmaceutische Chemie en Analyse van Geneesmiddelen, Faculteit Farmaceutische Wetenschappen, K.U. Leuven, Belgium
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199
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Abstract
A single-shot autocorrelator based on the two-photon excited fluorescence of BaF(2) in the visible region at 400 nm has been developed for ultrashort KrF laser pulses at 248 nm. Operation in the visible region offers simplification in the required optical components as compared with previously reported systems, which used ultraviolet fluorescence emission. The fluorescence intensity is also used to measure the two-photon absorption coefficient of BaF(2), yielding a value of β = 1.3 ± 0.4 × 10(-10) cm/W.
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200
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Li YM, Steffes M, Donnelly T, Liu C, Fuh H, Basgen J, Bucala R, Vlassara H. Prevention of cardiovascular and renal pathology of aging by the advanced glycation inhibitor aminoguanidine. Proc Natl Acad Sci U S A 1996; 93:3902-7. [PMID: 8632987 PMCID: PMC39457 DOI: 10.1073/pnas.93.9.3902] [Citation(s) in RCA: 145] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Human aging is impacted severely by cardiovascular disease and significantly but less overtly by renal dysfunction. Advanced glycation endproducts (AGEs) have been linked to tissue damage in diabetes and aging, and the AGE inhibitor aminoguanidine (AG) has been shown to inhibit renal and vascular pathology in diabetic animals. In the present study, the effects of AG on aging-related renal and vascular changes and AGE accumulation were studied in nondiabetic female Sprague-Dawley (S-D) and Fischer 344 (F344) rats treated with AG (0.1% in drinking water) for 18 mo. Significant increases in the AGE content in aged cardiac (P < 0.05), aortic (P < 0.005), and renal (P < 0.05) tissues were prevented by AG treatment (P < 0.05 for each tissue). A marked age-linked vasodilatory impairment in response to acetylcholine and nitroglycerine was prevented by AG treatment (P < 0.005), as was an age-related cardiac hypertrophy evident in both strains (P < 0.05). While creatinine clearance was unaffected by aging in these studies, the AGE/ creatinine clearance ratio declined 3-fold in old rats vs. young rats (S-D, P < 0.05; F344, P < 0.01), while it declined significantly less in AG-treated old rats (P < 0.05). In S-D but not in F344 rats, a significant (P < 0.05) age-linked 24% nephron loss was completely prevented by AG treatment, and glomerular sclerosis was markedly suppressed (P < 0.01). Age-related albuminuria and proteinuria were markedly inhibited by AG in both strains (S-D, P < 0.01; F344, P < 0.01). These data suggest that early interference with AGE accumulation by AG treatment may impart significant protection against the progressive cardiovascular and renal decline afflicting the last decades of life.
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Affiliation(s)
- Y M Li
- Picower Institute for Medical Research, Manhasset, NY 11030, USA
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