WorldWideScience

Sample records for acid-labile cholesterol-vinyl ether-peg

  1. Interferon alpha associated with systemic lupus erythematosus is not intrinsically acid labile

    OpenAIRE

    1989-01-01

    The physicochemical properties of apparently acid-labile IFN-alpha from patients with SLE have been studied. The antigenicity, apparent molecular size, and isoelectric point of SLE IFN-alpha are indistinguishable from those of conventional, previously characterized, acid-stable subspecies of IFN-alpha. However, after partial purification by anion-exchange chromatography, SLE IFN-alpha no longer exhibits acid lability, suggesting that other plasma factor(s) are responsible for the acid labilit...

  2. Human acid-labile subunit deficiency: clinical, endocrine and metabolic consequences.

    NARCIS (Netherlands)

    Domene, H.M.; Hwa, V.; Argente, J.; Wit, J.M.; Camacho-Hubner, C.; Jasper, H.G.; Pozo, J.; Duyvenvoorde, H.A. van; Yakar, S.; Fofanova-Gambetti, O.V.; Rosenfeld, R.G.; Hermus, A.R.M.M.; Twickler, T.B.; Kempers, M.J.E.

    2009-01-01

    The majority of insulin-like growth factor (IGF)-I and IGF-II circulate in the serum as a complex with the insulin-like growth factor binding protein (IGFBP)-3 or IGFBP-5, and an acid-labile subunit (ALS). The function of ALS is to prolong the half-life of the IGF-I-IGFBP-3/IGFBP-5 binary complexes.

  3. The acid-labile subunit of the ternary insulin-like growth factor complex in cirrhosis

    DEFF Research Database (Denmark)

    Møller, S; Juul, A; Becker, U;

    2000-01-01

    In the circulation, insulin-like growth factor-I (IGF-I) is bound in a trimeric complex of 150 kDa with IGF binding protein-3 (IGFBP-3) and the acid-labile subunit (ALS). Whereas circulating IGF-I and IGFBP-3 are reported to be low in patients with chronic liver failure, the level of ALS has...... not been described in relation to hepatic dysfunction. The aim of the present study was therefore to measure circulating and hepatic venous concentrations of ALS in relation to hepatic function and the IGF axis....

  4. The acid-labile subunit of human ternary insulin-like growth factor binding protein complex in serum

    DEFF Research Database (Denmark)

    Juul, A; Møller, S; Mosfeldt-Laursen, E;

    1998-01-01

    Circulating insulin-like growth factor-I (IGF-I) is predominantly bound in the trimeric complex comprised of IGF binding protein-3 (IGFBP-3) and acid-labile subunit (ALS). Circulating concentrations of IGF-I, IGFBP-3 and ALS are believed to reflect the GH secretory status, but the clinical use of...

  5. Acid-Labile Amphiphilic PEO-b-PPO-b-PEO Copolymers: Degradable Poloxamer Analogs.

    Science.gov (United States)

    Worm, Matthias; Kang, Biao; Dingels, Carsten; Wurm, Frederik R; Frey, Holger

    2016-05-01

    Poly ((ethylene oxide)-b-(propylene oxide)-b-(ethylene oxide)) triblock copolymers commonly known as poloxamers or Pluronics constitute an important class of nonionic, biocompatible surfactants. Here, a method is reported to incorporate two acid-labile acetal moieties in the backbone of poloxamers to generate acid-cleavable nonionic surfactants. Poly(propylene oxide) is functionalized by means of an acetate-protected vinyl ether to introduce acetal units. Three cleavable PEO-PPO-PEO triblock copolymers (Mn,total = 6600, 8000, 9150 g·mol(-1) ; Mn,PEO = 2200, 3600, 4750 g·mol(-1) ) have been synthesized using anionic ring-opening polymerization. The amphiphilic copolymers exhibit narrow molecular weight distributions (Ð = 1.06-1.08). Surface tension measurements reveal surface-active behavior in aqueous solution comparable to established noncleavable poloxamers. Complete hydrolysis of the labile junctions after acidic treatment is verified by size exclusion chromatography. The block copolymers have been employed as surfactants in a miniemulsion polymerization to generate polystyrene (PS) nanoparticles with mean diameters of ≈200 nm and narrow size distribution, as determined by dynamic light scattering and scanning electron microscopy. Acid-triggered precipitation facilitates removal of surfactant fragments from the nanoparticles, which simplifies purification and enables nanoparticle precipitation "on demand." PMID:27000789

  6. The acid-labile subunit of the ternary insulin-like growth factor complex in cirrhosis: relation to liver dysfunction

    DEFF Research Database (Denmark)

    Møller, S; Juul, A; Becker, U;

    2000-01-01

    BACKGROUND/AIMS: In the circulation, insulin-like growth factor-I (IGF-I) is bound in a trimeric complex of 150 kDa with IGF binding protein-3 (IGFBP-3) and the acid-labile subunit (ALS). Whereas circulating IGF-I and IGFBP-3 are reported to be low in patients with chronic liver failure, the level...... of ALS has not been described in relation to hepatic dysfunction. The aim of the present study was therefore to measure circulating and hepatic venous concentrations of ALS in relation to hepatic function and the IGF axis. METHODS: Twenty-five patients with cirrhosis (Child class A/B/C:5/10/10) and 30...... controls with normal liver function were studied. During a haemodynamic investigation, blood samples were collected from the hepatic vein and femoral artery, and the plasma concentrations of ALS, IGF-I and IGFBP-3 were determined. RESULTS: Hepatic venous and arterial concentrations of ALS were...

  7. An acid-labile block copolymer of PDMAEMA and PEG as potential carrier for intelligent gene delivery systems.

    Science.gov (United States)

    Lin, Song; Du, Fusheng; Wang, Yang; Ji, Shouping; Liang, Dehai; Yu, Lei; Li, Zichen

    2008-01-01

    Intelligent gene delivery systems based on physiologically triggered reversible shielding technology have evinced enormous interest due to their potential in vivo applications. In the present work, an acid-labile block copolymer consisting of poly(ethylene glycol) and poly(2-(dimethylamino)ethyl methacrylate) segments connected through a cyclic ortho ester linkage (PEG- a-PDMAEMA) was synthesized by atom transfer radical polymerization of DMAEMA using a PEG macroinitiator with an acid-cleavable end group. PEG- a-PDMAEMA condensed with plasmid DNA formed polyplex nanoparticles with an acid-triggered reversible PEG shield. The pH-dependent shielding/deshielding effect of PEG chains on the polyplex particles were evaluated by zeta potential and size measurements. At pH 7.4, polyplexes generated from PEG- a-PDMAEMA exhibited smaller particle size, lower surface charge, reduced interaction with erythrocytes, and less cytotoxicity compared to PDMAEMA-derived polyplexes. At pH 5.0, zeta potential of polyplexes formed from PEG- a-PDMAEMA increased, leveled up after 2 h of incubation and gradual aggregation occurred in the presence of bovine serum albumin (BSA). In contrast, the stably shielded polyplexes formed by DNA and an acid-stable block copolymer, PEG- b-PDMAEMA, did not change in size and zeta potential in 6 h. In vitro transfection efficiency of the acid-labile copolymer greatly increased after 6 h incubation at pH 5.0, approaching the same level of PDMAEMA, whereas there was only slight increase in efficiency for the stable copolymer, PEG- b-PDMAEMA.

  8. The ortho backbone amide linker (o-BAL) is an easily prepared and highly acid-labile handle for solid-phase synthesis

    DEFF Research Database (Denmark)

    Boas, Ulrik; Brask, Jesper; Christensen, J.B.;

    2002-01-01

    , followed by purification through steam distillation, Cleavage studies of Leu-enkephalin anchored to either o-BAL or p-BAL handles revealed that both handles were surprisingly acid-labile and released the peptide with dilute TFA (5% and even 1% TFA in CH2Cl2). This useful property allowed the synthesis of...

  9. PEG-detachable and acid-labile cross-linked micelles based on orthoester linked graft copolymer for paclitaxel release

    Energy Technology Data Exchange (ETDEWEB)

    Yuan Zhefan; Huang Jingyi; Liu Jing; Cheng Sixue; Zhuo Renxi; Li Feng, E-mail: lfsj2004@hotmail.com [Key Laboratory of Biomedical Polymers of Ministry of Education, College of Chemistry and Molecular Science, Wuhan University, Wuhan, 430072 (China)

    2011-08-19

    Polyethylene glycol detachable graft copolymer, mPEG-g-p(NAS-co-BMA), was synthesized by grafting 2-({omega}-methoxy)PEGyl-1,3-dioxan-5-ylamine onto poly(N-(acryloyloxy)succinimide-co-butyl methacrylate). Pseudo in situ cross-linking of the mPEG-g-p(NAS-co-BMA) was performed in dimethylformamide phosphate buffer (v/v = 1/1) by an acid-labile diamine cross-linker bearing two symmetrical cyclic orthoesters. The cross-linked (CL) micelles with different contents of mPEG segments represented different morphologies. The CL micelles containing approximately one mPEG segment exhibited 'echini' morphology whereas the CL micelle with approximately three mPEG segments formed nanowires. The hydrolysis rate of the CL micelles is highly pH-dependent and much more rapid at mild acid than physiological conditions. Hydrolyzates of the CL micelles formed vesicles because new amphiphilic copolymers were formed. Paclitaxel (PTX) was successfully loaded into the CL micelles and a controlled and pH-dependent release behavior was observed. No obvious cytotoxicity was found for the CL micelles at concentration as high as 800 mg l{sup -1}.

  10. PEG-detachable and acid-labile cross-linked micelles based on orthoester linked graft copolymer for paclitaxel release

    Science.gov (United States)

    Yuan, Zhefan; Huang, Jingyi; Liu, Jing; Cheng, Sixue; Zhuo, Renxi; Li, Feng

    2011-08-01

    Polyethylene glycol detachable graft copolymer, mPEG-g-p(NAS-co-BMA), was synthesized by grafting 2-(ω-methoxy)PEGyl-1,3-dioxan-5-ylamine onto poly(N-(acryloyloxy)succinimide-co-butyl methacrylate). Pseudo in situ cross-linking of the mPEG-g-p(NAS-co-BMA) was performed in dimethylformamide phosphate buffer (v/v = 1/1) by an acid-labile diamine cross-linker bearing two symmetrical cyclic orthoesters. The cross-linked (CL) micelles with different contents of mPEG segments represented different morphologies. The CL micelles containing approximately one mPEG segment exhibited 'echini' morphology whereas the CL micelle with approximately three mPEG segments formed nanowires. The hydrolysis rate of the CL micelles is highly pH-dependent and much more rapid at mild acid than physiological conditions. Hydrolyzates of the CL micelles formed vesicles because new amphiphilic copolymers were formed. Paclitaxel (PTX) was successfully loaded into the CL micelles and a controlled and pH-dependent release behavior was observed. No obvious cytotoxicity was found for the CL micelles at concentration as high as 800 mg l - 1.

  11. A simple and inexpensive enteric-coated capsule for delivery of acid-labile macromolecules to the small intestine.

    Science.gov (United States)

    Miller, Darren S; Parsons, Anne Michelle; Bresland, John; Herde, Paul; Pham, Duc Minh; Tan, Angel; Hsu, Hung-yao; Prestidge, Clive A; Kuchel, Tim; Begg, Rezaul; Aziz, Syed Mahfuzul; Butler, Ross N

    2015-07-01

    Understanding the ecology of the gastrointestinal tract and the impact of the contents on the host mucosa is emerging as an important area for defining both wellness and susceptibility to disease. Targeted delivery of drugs to treat specific small intestinal disorders such as small bowel bacterial overgrowth and targeting molecules to interrogate or to deliver vaccines to the remote regions of the small intestine has proven difficult. There is an unmet need for methodologies to release probes/drugs to remote regions of the gastrointestinal tract in furthering our understanding of gut health and pathogenesis. In order to address this concern, we need to know how the regional delivery of a surrogate labeled test compound is handled and in turn, if delivered locally as a liquid or powder, the dynamics of its subsequent handling and metabolism. In the studies we report on in this paper, we chose (13)C sodium acetate ((13)C-acetate), which is a stable isotope probe that once absorbed in the small intestine can be readily measured non-invasively by collection and analysis of (13)CO2 in the breath. This would provide information of gastric emptying rates and an indication of the site of release and absorptive capacity. In a series of in vitro and in vivo pig experiments, we assessed the enteric-protective properties of a commercially available polymer EUDRAGIT(®) L100-55 on gelatin capsules and also on DRcaps(®). Test results demonstrated that DRcaps(®) coated with EUDRAGIT(®) L100-55 possessed enhanced enteric-protective properties, particularly in vivo. These studies add to the body of knowledge regarding gastric emptying in pigs and also begin the process of gathering specifications for the design of a simple and cost-effective enteric-coated capsule for delivery of acid-labile macromolecules to the small intestine.

  12. Development of pH-sensitive self-nanoemulsifying drug delivery systems for acid-labile lipophilic drugs.

    Science.gov (United States)

    Zhao, Tianjing; Maniglio, Devid; Chen, Jie; Chen, Bin; Migliaresi, Claudio

    2016-03-01

    Oral administration is the most convenient way of all the drug delivery routes. Orally administered bioactive compounds must resist the harsh acidic fluids or enzyme digestion in stomach, to reach their absorbed destination in small intestine. This is the case for silibinin, a drug used to protect liver cells against toxins that has also been demonstrated in vitro to possess anti-cancer effects. However, as many other drugs, silibinin can degrade in the stomach due to the action of the gastric fluid. The use of pH-sensitive self-nanoemulsifying drug delivery systems (pH-SNEDDS) could overcome the drawback due to degradation of the drug in the stomach while enhancing its solubility and dissolution rate. In this paper we have investigated pH-sensitive self-nanoemulsifying formulations containing silibinin as model drug. Pseudo-ternary phase diagrams have been constructed in order to identify the self-emulsification regions under different pH. Solubility of silibinin in selected formulations has been assessed and stability of the pure drug and of the silibinin loaded pH-SNEDDS formulations in simulated gastric fluid had been compared. Droplet size of the optimized pH-SNEDDS has been correlated to pH, volume of dilution medium and silibinin loading amount. TEM (transmission electron microscopy) studies have shown that emulsion droplets had spherical shape and narrow size distribution. In vitro drug release studies of the optimal pH-SNEDDS indicated substantial increase of the drug release and release rate in comparison to pure silibinin and to the commercial silibinin tablet. The results indicated that pH-SNEDDS have potential to improve the biopharmaceutics properties of acid-labile lipophilic drugs.

  13. pH-responsive biodegradable micelles based on acid-labile polycarbonate hydrophobe: synthesis and triggered drug release.

    Science.gov (United States)

    Chen, Wei; Meng, Fenghua; Li, Feng; Ji, Shun-Jun; Zhong, Zhiyuan

    2009-07-13

    pH-responsive biodegradable micelles were prepared from block copolymers comprising of a novel acid-labile polycarbonate hydrophobe and poly(ethylene glycol) (PEG). Two new cyclic aliphatic carbonate monomers, mono-2,4,6-trimethoxybenzylidene-pentaerythritol carbonate (TMBPEC, 2a) and mono-4-methoxybenzylidene-pentaerythritol carbonate (MBPEC, 2b) were designed and successfully synthesized via a two-step procedure. The ring-opening polymerization of 2a or 2b in the presence of methoxy PEG in dichloromethane at 50 °C using zinc bis[bis(trimethylsilyl)amide] as a catalyst yielded the corresponding block copolymers PEG-PTMBPEC (3a) or PEG-PMBPEC (3b) with low polydispersities (PDI 1.03-1.04). The copolymerization of D,L-lactide (DLLA) and 2a under otherwise the same conditions could also proceed smoothly to afford PEG-P(TMBPEC-co-DLLA) (3c) block copolymer. These block copolymers readily formed micelles in water with sizes of about 120 nm as determined by dynamic light scattering (DLS). The hydrolysis of the acetals of the polycarbonate was investigated using UV/vis spectroscopy. The results showed that the acetals of micelles 3a, while stable at pH 7.4 are prone to rapid hydrolysis at mildly acidic pH of 4.0 and 5.0, with a half-life of 1 and 6.5 h, respectively. The acetal hydrolysis resulted in significant swelling of micelles, as a result of change of hydrophobic polycarbonate to hydrophilic polycarbonate. In comparison, the acetals of PMBPEC of micelles 3b displayed obviously slower hydrolysis at the same pH. Both paclitaxel and doxorubicin could be efficiently encapsulated into micelles 3a achieving high drug loading content (13.0 and 11.7 wt %, respectively). The in vitro release studies showed clearly a pH dependent release behavior, that is, significantly faster drug release at mildly acidic pH of 4.0 and 5.0 compared to physiological pH. These pH-responsive biodegradable micelles are promising as smart nanovehicles for targeted delivery of anticancer drugs.

  14. Combination of acid labile detergent and C18 Empore™ disks for improved identification and sequence coverage of in-gel digested proteins.

    Science.gov (United States)

    Koehn, Henning; Lau, Benjamin; Clerens, Stefan; Plowman, Jeffrey E; Dyer, Jolon M; Ramli, Umi Salamah; Deb-Choudhury, Santanu

    2011-04-01

    A protocol for improved extraction of peptides from in-gel protein digests, using a combination of the acid labile surfactant, sodium deoxycholate (SDC) and C18 Empore™ membranes, is presented. This approach results in better mass spectrum quality, higher numbers of identified peptide peaks and improved identification scores compared to standard tryptic digestion protocols, or protocols using only SDC or only C18 Empore™ disks. The advantages of the new protocol are demonstrated for two different types of samples: Merino wool intermediate filament proteins and Elaeis guineensis (oil palm) mesocarp proteins. PMID:21327873

  15. Case report: low circulating IGF-I levels due to Acid-Labile Subunit deficiency in adulthood are not associated with early development of atherosclerosis and impaired heart function

    NARCIS (Netherlands)

    Rensing, K.L.; Duyvenvoorde, H.A. van; Cramer, M.J.; Teske, A.J.; Prokop, M.; Stroes, E.S.; Wit, J.M.; Hermus, A.R.M.M.; Twickler, T.B.

    2011-01-01

    OBJECTIVE: Decreased insulin-like growth factor-I (IGF-I) levels in adults have been associated with an increased risk of ischemic heart disease and heart failure. It is currently unknown whether patients with low circulating IGF-I levels due to a homozygous acid-labile subunit (IGFALS) gene mutatio

  16. Novel acid-labile subunit ( IGFALS ) mutation p.T145K (c.434C>A) in a patient with ALS deficiency, normal stature and immunological dysfunction.

    Science.gov (United States)

    Schreiner, Felix; Schoenberger, Stefan; Koester, Bernhard; Domené, Horacio M; Woelfle, Joachim

    2013-01-01

    We report a novel missense mutation p.T145K in the insulin-like growth factor (IGF) acid-labile subunit (IGFALS) gene identified in a Turkish patient with normal growth, transient pancytopenic episodes and signs of immunological dysfunction. Because of recurrent cutaneous mycoses and absence of pubertal development until the age of 14.75 years we determined several endocrine parameters in order to rule out autoimmune-polyendocrine syndromes. Despite a normal height between the 25th and 50th percentile we found severely decreased IGF-1 and undetectably low IGFBP-3 levels. Laboratory signs of immunological dysfunction included reduced total lymphocyte count with diminished B and T helper cell fractions, decreased serum concentrations of IgM and IgG subclass 4, and elevated antinuclear antibody and anti-dsDNA titers as well as persistently high interleukin-2-receptor levels. Further endocrine work-up revealed elevated fasting insulin and undetectably low ALS serum levels, leading to the diagnosis of ALS deficiency. Sequencing of the coding region of the IGFALS gene showed a novel homozygous missense mutation (c.434C>A; p.T145K). Since immunological abnormalities have not been reported in more than 20 ALS-deficient patients so far and our patient was born to consanguineous parents, a second autosomal recessive defect is likely to underlie the immunological phenotype, although a causative role of IGFALS p.T145K cannot be entirely ruled out. PMID:24296365

  17. Application of nanoparticles for oral delivery of acid-labile lansoprazole in the treatment of gastric ulcer: in vitro and in vivo evaluations.

    Science.gov (United States)

    Alai, Milind; Lin, Wen Jen

    2015-01-01

    The aim of this study was to develop nanoparticles for oral delivery of an acid-labile drug, lansoprazole (LPZ), for gastric ulcer therapy. LPZ-loaded positively charged Eudragit(®) RS100 nanoparticles (ERSNPs-LPZ) and negatively charged poly(lactic-co-glycolic acid) nanoparticles (PLGANPs-LPZ) were prepared. The effect of charge on nanoparticle deposition in ulcerated and non-ulcerated regions of the stomach was investigated. The cellular uptake of nanoparticles in the intestine was evaluated in a Caco-2 cell model. The pharmacokinetic performance and ulcer healing response of LPZ-loaded nanoparticles following oral administration were evaluated in Wistar rats with induced ulcers. The prepared drug-loaded ERSNPs-LPZ and PLGANPs-LPZ possessed opposite surface charge (+38.5±0.3 mV versus -27.3±0.3 mV, respectively) and the particle size was around 200 nm with a narrow size distribution. The negatively charged PLGANPs adhered more readily to the ulcerated region (7.22%±1.21% per cm(2)), whereas the positively charged ERSNPs preferentially distributed in the non-ulcerated region (8.29%±0.35% per cm(2)). Both ERSNPs and PLGANPs were prominent uptake in Caco-2 cells, too. The nanoparticles sustained and prolonged LPZ concentrations up to 24 hours, and the half-life and mean residence time of LPZ were prolonged by 3.5-fold and 4.5-fold, respectively, as compared with LPZ solution. Oral administration of LPZ-loaded nanoparticles healed 92.6%-95.7% of gastric ulcers in Wistar rats within 7 days.

  18. Application of nanoparticles for oral delivery of acid-labile lansoprazole in the treatment of gastric ulcer: in vitro and in vivo evaluations

    Directory of Open Access Journals (Sweden)

    Alai M

    2015-06-01

    Full Text Available Milind Alai,1 Wen Jen Lin1,2 1Graduate Institute of Pharmaceutical Sciences, School of Pharmacy, 2Drug Research Center, College of Medicine, National Taiwan University, Taipei, Taiwan Abstract: The aim of this study was to develop nanoparticles for oral delivery of an acid-labile drug, lansoprazole (LPZ, for gastric ulcer therapy. LPZ-loaded positively charged Eudragit® RS100 nanoparticles (ERSNPs-LPZ and negatively charged poly(lactic-co-glycolic acid nanoparticles (PLGANPs-LPZ were prepared. The effect of charge on nanoparticle deposition in ulcerated and non-ulcerated regions of the stomach was investigated. The cellular uptake of nanoparticles in the intestine was evaluated in a Caco-2 cell model. The pharmacokinetic performance and ulcer healing response of LPZ-loaded nanoparticles following oral administration were evaluated in Wistar rats with induced ulcers. The prepared drug-loaded ERSNPs-LPZ and PLGANPs-LPZ possessed opposite surface charge (+38.5±0.3 mV versus -27.3±0.3 mV, respectively and the particle size was around 200 nm with a narrow size distribution. The negatively charged PLGANPs adhered more readily to the ulcerated region (7.22%±1.21% per cm2, whereas the positively charged ERSNPs preferentially distributed in the non-ulcerated region (8.29%±0.35% per cm2. Both ERSNPs and PLGANPs were prominent uptake in Caco-2 cells, too. The nanoparticles sustained and prolonged LPZ concentrations up to 24 hours, and the half-life and mean residence time of LPZ were prolonged by 3.5-fold and 4.5-fold, respectively, as compared with LPZ solution. Oral administration of LPZ-loaded nanoparticles healed 92.6%–95.7% of gastric ulcers in Wistar rats within 7 days. Keywords: nanoparticles, lansoprazole, Eudragit® RS100, PLGA

  19. Effects of short-term caloric restriction on circulating free IGF-I, acid-labile subunit, IGF-binding proteins (IGFBPs)-1-4, and IGFBPs-1-3 protease activity in obese subjects

    DEFF Research Database (Denmark)

    Rasmussen, Michael Højby; Juul, Anders; Kjems, Lise Lund;

    2006-01-01

    Decreased levels of GH and total IGF-I have been reported in obesity. It has been hypothesized that increased free (biologically active) IGF-I levels generated from IGF-binding protein (IGFBP) protease activity could be the mechanism for the low GH release in dieting obese subjects. However, no...... published data exist on free IGF-I levels, acid labile subunit (ALS), or IGFBP protease activity in relation to GH release during a hypocaloric diet. The main purpose of this study was to determine free IGF-I, ALS, IGFBPs-1-4, and IGFBPs-1-3 protease activity in relation to 24-h GH release before and after...

  20. Effects of short-term caloric restriction on circulating free IGF-I, acid-labile subunit, IGF-binding proteins (IGFBPs)-1-4, and IGFBPs-1-3 protease activity in obese subjects

    DEFF Research Database (Denmark)

    Rasmussen, Michael Højby; Juul, Anders; Kjems, Lise Lund;

    2006-01-01

    Decreased levels of GH and total IGF-I have been reported in obesity. It has been hypothesized that increased free (biologically active) IGF-I levels generated from IGF-binding protein (IGFBP) protease activity could be the mechanism for the low GH release in dieting obese subjects. However, no...... published data exist on free IGF-I levels, acid labile subunit (ALS), or IGFBP protease activity in relation to GH release during a hypocaloric diet. The main purpose of this study was to determine free IGF-I, ALS, IGFBPs-1-4, and IGFBPs-1-3 protease activity in relation to 24-h GH release before and after...... a short-term very low-calorie diet (VLCD)....

  1. Acid-labile sulfides in shallow marine bottom sediments: A review of the impact on ecosystems in the Azov Sea, the NE Black Sea shelf and NW Adriatic lagoons

    Science.gov (United States)

    Sorokin, Yu. I.; Zakuskina, O. Yu

    2012-02-01

    Acid-labile sulfides (LS) increase in bottom sediments at sites in the Azov Sea, at the NE Black Sea shelf and in the coastal lagoons of NW Adriatic Sea experiencing direct impacts of anthropogenic pollution. Fresh anthropogenic organic matter stimulates the bacterial sulfate reduction and here the rate of the LS production overcomes their loss during the oxidation and pyritization. This results in the expansion of reduced sediment layer up to the bottom surface. The LS concentration in the reduced sediments varies between 300 and 2000 mg S l -1 of wet silt depending on the size of pollution loading and on the rate of sedimentation. In the oxidized sediments away from the direct pollution impact, the LS concentration did not exceed 100-150 mg S l -1. Being a strong cytochrome toxin, the LS adversely affect the coastal ecosystems. The concentrations over 600 mg S l -1 result in quasi total benthic mortality whereas >300-400 mg S l -1 depletes the benthic faunal abundance and taxonomic diversity. Accumulation of the LS in sediments also induces nocturnal hypoxia and stimulates domination of toxic cyanobacteria in the pelagic phytocenoses.

  2. A simple and inexpensive enteric-coated capsule for delivery of acid-labile macromolecules to the small intestine%题目:一种用于递送酸度敏感大分子到小肠的简易且廉价的肠溶胶囊

    Institute of Scientific and Technical Information of China (English)

    Darren S MILLER; Rezaul BEGG; Syed Mahfuzul AZIZ; Ross N BUTLER; Anne Michelle PARSONS; John BRESLAND; Paul HERDE; Duc Minh PHAM; Angel TAN; Hung-yao HSU; Clive A PRESTIDGE; Tim KUCHEL

    2015-01-01

    Understanding the ecology of the gastrointestinal tract and the impact of the contents on the host mucosa is emerging as an important area for defining both welness and susceptibility to disease. Targeted delivery of drugs to treat specific smal intestinal disorders such as smal bowel bacterial overgrowth and targeting molecules to interrogate or to deliver vaccines to the remote regions of the smal intestine has proven difficult. There is an unmet need for methodologies to release probes/drugs to remote regions of the gastrointestinal tract in furthering our understanding of gut health and pathogenesis. In order to address this concern, we need to know how the regional delivery of a sur-rogate labeled test compound is handled and in turn, if delivered localy as a liquid or powder, the dynamics of its subsequent handling and metabolism. In the studies we report on in this paper, we chose13C sodium acetate (13C-acetate), which is a stable isotope probe that once absorbed in the smal intestine can be readily measured non-invasively by colection and analysis of13CO2 in the breath. This would provide information of gastric emptying rates and an indication of the site of release and absorptive capacity. In a series ofin vitro andin vivo pig experiments, we assessed the enteric-protective properties of a commercialy available polymer EUDRAGIT® L100-55 on gelatin capsules and also on DRcaps®. Test results demonstrated that DRcaps® coated with EUDRAGIT® L100-55 possessed enhanced enteric-protective properties, particularlyin vivo. These studies add to the body of knowledge regarding gastric emptying in pigs and also begin the process of gathering specifications for the design of a simple and cost-effective enteric-coated capsule for delivery of acid-labile macromolecules to the smal intestine.%目的:通过开展胃肠道远端释放药物的研究,以增加对肠道健康和发病机制的理解。创新点:本研究选择了13C醋酸钠作为同位素探针,

  3. A simple and inexpensive enteric-coated capsule for delivery of acid-labile macromolecules to the small intestine%题目:一种用于递送酸度敏感大分子到小肠的简易且廉价的肠溶胶囊

    Institute of Scientific and Technical Information of China (English)

    Darren S MILLER; Rezaul BEGG; Syed Mahfuzul AZIZ; Ross N BUTLER; Anne Michelle PARSONS; John BRESLAND; Paul HERDE; Duc Minh PHAM; Angel TAN; Hung-yao HSU; Clive A PRESTIDGE; Tim KUCHEL

    2015-01-01

    enteric-protective properties of a commercialy available polymer EUDRAGIT® L100-55 on gelatin capsules and also on DRcaps®. Test results demonstrated that DRcaps® coated with EUDRAGIT® L100-55 possessed enhanced enteric-protective properties, particularlyin vivo. These studies add to the body of knowledge regarding gastric emptying in pigs and also begin the process of gathering specifications for the design of a simple and cost-effective enteric-coated capsule for delivery of acid-labile macromolecules to the smal intestine.

  4. The acid-labile subunit of human ternary insulin-like growth factor binding protein complex in serum

    DEFF Research Database (Denmark)

    Juul, A; Møller, S; Mosfeldt-Laursen, E;

    1998-01-01

    deficiency (GHD). We found: 1) no significant arteriovenous gradient over the liver ofALS, IGF-I, and IGFBP-3; 2) the diurnal variation of ALS was 12% (mean coefficient of variation percent); 3) ALS levels increased throughout childhood with maximal levels in puberty, with a subsequent decrease with age...... of ALS determination is not known. We therefore, determined the: 1) hepatosplanchnic release of ALS by liver vein catheterization (n=30); 2) 24-h diurnal variation of ALS (n=8); 3) normal age-related ranges of circulating ALS (n=1158); 4) diagnostic value of ALS in 108 patients with childhood-onset GH...... is not measurable by this approach or, alternatively, that the liver is not the primary source of circulating ALS, IGF-I, or IGFBP-3 in humans. In conclusion, we have provided extensive normal data for a novel ALS assay and found that circulating ALS levels exhibit minor diurnal variation. We suggest that ALS...

  5. Synthesis and application of acid labile anchor groups for the synthesis of peptide amides by Fmoc-solid-phase peptide synthesis.

    Science.gov (United States)

    Breipohl, G; Knolle, J; Stüber, W

    1989-10-01

    The preparation and application of a new linker for the synthesis of peptide amides using a modified Fmoc-method is described. The new anchor group was developed based on our experience with 4,4'-dimethoxybenzhydryl (Mbh)-protecting group for amides. Lability towards acid treatment was increased dramatically and results in an easy cleavage procedure for the preparation of peptide amides. The synthesis of N-9-fluorenylmethoxycarbonyl- ([5-carboxylatoethyl-2.4-dimethoxyphenyl)- 4'-methoxyphenyl]-methylamin is reported in detail. This linker was coupled to a commercially available aminomethyl polystyrene resin. Peptide synthesis proceeded smoothly using HOOBt esters of Fmoc-amino acids. Release of the peptide amide and final cleavage of the side chain protecting groups was accomplished by treatment with trifluoroacetic acid-dichloromethane mixtures in the presence of scavengers. The synthesis of peptide amides such as LHRH and C-terminal hexapeptide of secretin are given as examples.

  6. Total and free insulin-like growth factor I, insulin-like growth factor binding protein 3 and acid-labile subunit reflect clinical activity in acromegaly

    DEFF Research Database (Denmark)

    Sneppen, S B; Lange, Merete Wolder; Pedersen, L M;

    2001-01-01

    insulin-like growth factor binding protein-3 (IGFBP-3) with PV(pos) of 0.69 and 0.71 and PV(neg) of 0.91 and 0.92 respectively. We conclude that free IGF-I is more closely related than total IGF-I to perceived disease activity and is as such useful when evaluating previously treated acromegaly for disease...... activity. Total IGF-I, IGFBP-3 and ALS possess a higher PV(neg) for the clinical disease activity. None of the parameters can at present be claimed to be superior to the others and thus all the measured parameters are recommended to be part of the evaluation of acromegalic patients....

  7. Total and free insulin-like growth factor I, insulin-like growth factor binding protein 3 and acid-labile subunit reflect clinical activity in acromegaly

    DEFF Research Database (Denmark)

    Sneppen, S B; Lange, Merete Wolder; Pedersen, L M;

    2001-01-01

    The aim was to evaluate, markers of disease activity in acromegaly in relation to perceived disease activity. Thirty-seven consecutively treated, acromegalic patients, classified by clinical symptoms as inactive (n=16), slightly active (n=10) and active (n=11), entered the study. When evaluating......-like growth factor binding protein-3 (IGFBP-3) with PV(pos) of 0.69 and 0.71 and PV(neg) of 0.91 and 0.92 respectively. We conclude that free IGF-I is more closely related than total IGF-I to perceived disease activity and is as such useful when evaluating previously treated acromegaly for disease activity...

  8. Optimization of enzymatic synthesis of asialoglycoprotein receptor ligand cholesterol-vinyl sebacate-lactitol%去唾液酸糖蛋白受体配体胆固醇-半乳糖苷的酶促合成优化研究

    Institute of Scientific and Technical Information of China (English)

    陈静; 程怡; 郑品劲; 聂华; 陈宇潮; 仝一丹; 罗利华; 李朝

    2015-01-01

    目的 在有机相中利用酶促反应合成能被去唾液酸糖蛋白受体(ASGPR)特异性识别的配体胆固醇-半乳糖苷分子,对其合成工艺进行优化.方法 采用质谱和核磁碳谱鉴别产物结构;单因素和正交设计法优化酶促合成条件.结果 酶促最佳条件为底物胆固醇癸二酸乙烯酯(CH-VS)与乳糖醇(LA)物质的量之比4∶1,脂肪酶Novozym 435 25 mg,反应32 h,产率高达92%.结论 该方法高效、反应条件可行、产物专一.

  9. A NOVEL THERMOSENSITIVE POLYMER WITH pH-DEPENDENT DEGRADATION FOR DRUG DELIVERY

    OpenAIRE

    Garripelli, Vivek Kumar; Kim, Jin-Ki; Namgung, Ran; Kim, Won Jong; Repka, Michael A.; Jo, Seongbong

    2009-01-01

    A class of thermosensitive biodegradable multiblock copolymers with acid-labile acetal linkages were synthesized from Pluronic® triblock copolymers (Pluronic® P85 and P104) and di-(ethylene glycol) divinyl ether. The novel polymers were engineered to form thermogels at body temperature and degrade in acidic environment. The Pluronic®-based acid-labile polymers were characterized using nuclear magnetic resonance, gel permeation chromatography and differential scanning calorimetry. In vitro bio...

  10. Biodegradable containers from green waste materials

    Science.gov (United States)

    Sartore, Luciana; Schettini, Evelia; Pandini, Stefano; Bignotti, Fabio; Vox, Giuliano; D'Amore, Alberto

    2016-05-01

    Novel biodegradable polymeric materials based on protein hydrolysate (PH), derived from waste products of the leather industry, and poly(ethylene glycol) diglycidyl ether (PEG) or epoxidized soybean oil (ESO) were obtained and their physico-chemical properties and mechanical behaviour were evaluated. Different processing conditions and the introduction of fillers of natural origin, as saw dust and wood flour, were used to tailor the mechanical properties and the environmental durability of the product. The biodegradable products, which are almost completely manufactured from renewable-based raw materials, look promising for several applications, particularly in agriculture for the additional fertilizing action of PH or in packaging.

  11. Steric effects in release of amides from linkers in solid-phase synthesis. Molecular mechanics modeling of key step in peptide and combinatorial chemistry

    DEFF Research Database (Denmark)

    Norrby, Per-Ola; Jensen, Knud Jørgen

    2006-01-01

    Acidolytic release of an amide from a solid support by C-N bond cleavage is all ubiquitous and crucial step in many solid-phase syntheses. We have used molecular modeling of a pseudo-equilibrium to explore substituent and steric effects in the release of peptides. The high acid-lability of the...... the lability of a linkage. In addition, predictions indicated that steric effects from the C-alpha-substituent in a BAL anchored amino acid residue should accelerate the acidolytic release. The finding that steric crowding leads to increased acid-lability will be important for further development and...

  12. Efficient and Mild Microwave-Assisted Stepwise Functionalization of Naphthalenediimide with α-Amino Acids

    NARCIS (Netherlands)

    Pengo, Paolo; Pantoş, G. Dan; Otto, Sijbren; Sanders, Jeremy K.M.

    2006-01-01

    Microwave dielectric heating proved to be an efficient method for the one-pot and stepwise syntheses of symmetrical and unsymmetrical naphthalenediimide derivatives of α-amino acids. Acid-labile side chain protecting groups are stable under the reaction conditions; protection of the α-carboxylic gro

  13. Metabolism of ammonium fluoride and sodium monofluoroacetate by experimental Acacia georginae

    Energy Technology Data Exchange (ETDEWEB)

    Hall, R.J.

    1974-01-01

    Plants of Acacia georginae (one of numerous toxic tropical species now known to contain monofluoroacetate) were cultivated in nutrient-washed quartz, and in soil. Attempts were made to induce the formation of organic fluorine by treatment of the roots with a solution of ammonium fluoride. Only small amounts of carbon-fluorine material were measured in the leaves and roots, and examinations by physico-chemical methods failed to detect any evidence of the presence of monofluoroacetate in any of the plants. Similar plants were treated with sodium monofluoroacetate which underwent considerable degradation to an acid-labile form of fluorine (probably inorganic fluoride). The results of the analyses of the roots and leaves for fluorine revealed that the difference between acid-labile (diffusible) fluoride and total fluorine cannot be taken as a measure of the organic fluorine.

  14. Human immune interferon: induction in lymphoid cells by a calcium ionophore.

    OpenAIRE

    Dianzani, F; Monahan, T. M.; Georgiades, J; Alperin, J B

    1980-01-01

    Human lymphocyte cultures produced interferon after treatment with the calcium ionophore A23187, but not after treatment with potassium ionophore nonactin. Interferon production was detectable between 3 and 6 h after ionophore treatment and reached the maximum level between 12 and 24 h. Ionophore-induced interferon appeared to be immune interferon on the basis of acid lability, lack of neutralization by antibody to leukocyte interferon, slow kinetics of activation of the antiviral state, and ...

  15. Efficient and Mild Microwave-Assisted Stepwise Functionalization of Naphthalenediimide with α-Amino Acids

    OpenAIRE

    Pengo, Paolo; Pantoş, G. Dan; Otto, Sijbren; Sanders, Jeremy K. M.

    2006-01-01

    Microwave dielectric heating proved to be an efficient method for the one-pot and stepwise syntheses of symmetrical and unsymmetrical naphthalenediimide derivatives of α-amino acids. Acid-labile side chain protecting groups are stable under the reaction conditions; protection of the α-carboxylic group is not required. The stepwise condensation of different amino acids resulted in high yields of unsymmetrical naphthalenediimides. The reaction proceeds without racemization and is essentially qu...

  16. One-pot multienzyme synthesis of Lewis x and sialyl Lewis x antigens

    OpenAIRE

    Yu, Hai; Lau, Kam; Li, Yanhong; Sugiarto, Go; Chen, Xi

    2012-01-01

    L-Fucose has been found abundantly in human milk oligosaccharides, bacterial lipopolysaccharides, glycolipids, and many N- and O-linked glycans produced by mammalian cells. Fucose-containing carbohydrates have important biological functions. Alterations in the expression of fucosylated oligosaccharides have been observed in several pathological processes such as cancer and atherosclerosis. Chemical formation of fucosidic bonds is challenging due to its acid lability. Enzymatic construction of...

  17. Simulating the co-encapsulation of drugs in a "smart" core-shell-shell polymer nanoparticle.

    Science.gov (United States)

    Buxton, Gavin A

    2014-03-01

    A coarse-grained lattice Monte Carlo method is used to simulate co-encapsulation and delivery of both a hydrophilic and hydrophobic drug from polymer nanoparticles. In particular, core-shell-shell polymer nanoparticles with acid-labile bonds are simulated, and the preferential release of the encapsulated drugs near more acidic tumors is captured. While these simple models lack the molecular details of a real system, they can reveal interesting insights concerning the effects of entropy and enthalpy in these systems.

  18. Traceless Azido Linker for the Solid-Phase Synthesis of NH-1,2,3-Triazoles via Cu-Catalyzed Azide-Alkyne Cycloaddition Reactions

    DEFF Research Database (Denmark)

    Cohrt, Anders Emil; Jensen, Jakob Feldthusen; Nielsen, Thomas Eiland

    2010-01-01

    A broadly useful acid-labile traceless azido linker for the solid-phase synthesis of NH-1,2,3-triazoles is presented. A variety of alkynes were efficiently immobilized on a range of polymeric supports by Cu(I)-mediated azide-alkyne cycloadditions. Supported triazoles showed excellent compatibilit...... with subsequent peptide chemistry. Release of pure material (typically >95%) from the solid support was readily achieved by treatment with aqueous TFA....

  19. Fifty cases of human immunodeficiency virus (HIV) infection: immunoultrastructural study of circulating lymphocytes.

    OpenAIRE

    Feremans, W W; Huygen, K.; Menu, R; Farber, C M; de Caluwe, J P; van Vooren, J P; Marcelis, L; Andre, L; Brasseur, M; Bondue, H

    1988-01-01

    The peripheral lymphocytes of 50 cases of human immunodeficiency virus (HIV) infection (13 of acquired immune deficiency syndrome (AIDS), 17 of AIDS related complex (ARC), and 20 healthy carriers) were studied immunoultrastructurally. The prevalence of "tubuloreticular structures" and "tubular confronting cisternae" increased with the progression of the disease. Numerous tubular confronting cisternae were noted in patients presenting with a high serum acid labile alpha-interferon values. The ...

  20. B(C6F5)3 catalyzed one-pot three-component Biginelli reaction: An efficient and environmentally benign protocol for the synthesis of 3,4-dihydropyrimidin-2(1)-ones/thiones

    Indian Academy of Sciences (India)

    Santosh Kumar Prajapti; Keshav Kumar Gupta; Bathini Nagendra Babu

    2015-06-01

    Tris(pentafluorophenyl)borane catalyzed, one-pot, simple, efficient and environmentally benign protocol for the synthesis of dihydropyrimidinones/thiones via Biginelli reaction has been described. The main highlights of the present protocol is low catalyst loading, low toxicity, compatibility with acid-labile-protecting groups, short reaction time, consistently excellent yields and simple reaction/workup procedure. Moreover, the applicability of the present methodology for large-scale synthesis of monastrol highlights its potential for bulk synthesis.

  1. The Ritter Reaction in Liquid Sulfur Dioxide

    OpenAIRE

    Posevins, D

    2015-01-01

    Ritter reaction is associated with a one-pot process for amide bond formation, that involves nitrile and a group, capable of giving a relatively stable carbenium ion (originally - alcohol or alkene) in strongly ionizing acidic medium. The classical Ritter reaction involves use of at least stoichiometric amounts of a corrosive Brønsted acid (i.e., conc. H2SO4), thus often limiting its applicability to compounds containing acid labile functional groups. Nevertheless because of its atom economy ...

  2. Structural analysis by reductive cleavage with LiAlH4 of an allyl ether choline-phospholipid, archaetidylcholine, from the hyperthermophilic methanoarchaeon Methanopyrus kandleri

    Directory of Open Access Journals (Sweden)

    Masateru Nishihara

    2002-01-01

    Full Text Available A choline-containing phospholipid (PL-4 in Methanopyrus kandleri cells was identified as archaetidylcholine, which has been described by Sprott et al. (1997. The PL-4 consisted of a variety of molecular species differing in hydrocarbon composition. Most of the PL-4 was acid-labile because of its allyl ether bond. The identity of PL-4 was confirmed by thin-layer chromatography (TLC followed by positive staining with Dragendorff-reagent and fast-atom bombardment–mass spectrometry. A new method of LiAlH4 hydrogenolysis was developed to cleave allyl ether bonds and recover the corresponding hydrocarbons. We confirmed the validity of the LiAlH4 method in a study of the model compound synthetic unsaturated archaetidic acid (2,3-di-O-geranylgeranyl-sn-glycerol-1-phosphate. Saturated ether bonds were not cleaved by the LiAlH4 method. The hydrocarbons formed following LiAlH4 hydrogenolysis of PL-4 were identified by gas–liquid chromatography and mass spectrometry. Four kinds of hydrocarbons with one to four double bonds were detected: 47% of the hydrocarbons had four double bonds; 11% had three double bonds; 14% had two double bonds; 7% had one double bond; and 6% were saturated species. The molecular species composition of PL-4 was also estimated based on acid lability: 77% of the molecular species had two acid-labile hydrocarbons; 11% had one acid-labile and one acid-stable hydrocarbon; and 11% had two acid-stable hydrocarbons. To our knowledge, this is the first report of a specific chemical degradation method for the structural analysis of allyl ether phospholipid in archaea.

  3. Matrix-induced fragmentation of P3′-N5′ phosphoramidate-containing DNA: high-throughput MALDI-TOF analysis of genomic sequence polymorphisms

    OpenAIRE

    Shchepinov, Mikhail S.; Denissenko, Mikhail F.; Smylie, Kevin J.; Wörl, Ralf J.; Leppin, A. Lorieta; Cantor, Charles R.; Rodi, Charles P.

    2001-01-01

    Chemical and enzymatic approaches were used to produce polynucleotide fragments containing acid-labile internucleotide P3′-N5′ phosphoramidate bonds, either in a surface-bound form or in solution. The primer extension reaction utilizing 5′-amino-5′-deoxynucleoside 5′-triphosphates generates polynucleotides that can be fragmented into short, easy-to-analyze pieces simply by being premixed with the acidic matrices typically used for MALDI-TOF mass spectrometry of nuc...

  4. Shell-sheddable, pH-sensitive supramolecular nanoparticles based on ortho ester-modified cyclodextrin and adamantyl PEG.

    Science.gov (United States)

    Ji, Ran; Cheng, Jing; Yang, Ting; Song, Cheng Cheng; Li, Lei; Du, Fu-Sheng; Li, Zi-Chen

    2014-10-13

    We report a new type of pH-sensitive supramolecular aggregates which possess a programmable character of sequential dePEGylation and degradation. As a platform of designing and building multifunctional supramolecular nanoparticles, a family of 6-OH ortho ester-modified β-cyclodextrin (β-CD) derivatives have been synthesized via the facile reaction between β-CD and cyclic ketene acetals with different alkyl lengths. These asymmetric acid-labile β-CD derivatives formed amphiphilic supramolecules with adamantane-modified PEG through host-guest interaction in polar solvents such as ethanol. The supramolecules can self-assemble in water to form acid-labile supramolecular aggregates. The results of TEM and light scattering measurements demonstrate that the size and morphology of the aggregates are influenced by the alkyl or PEG length and the host-guest feed ratio. By carefully balancing the alkyl and PEG lengths and adjusting the host-guest ratio, well-dispersed vesicles (50-100 nm) or sphere-like nanoparticles (200-500 nm) were obtained. Zeta potential measurements reveal that these supramolecular aggregates are capable of being surface-functionalized via dynamic host-guest interaction. The supramolecular aggregates were stable at pH 8.4 for at least 12 h as proven by the (1)H NMR and LLS measurements. However, rapid dePEGylation occurred at pH 7.4 due to the hydrolysis of the ortho ester linkages locating at the interface, which resulted in aggregation of the dePEGylated hydrophobic inner cores. Upon further decreasing the pH to 6.4, the hydrophobic cores were further degraded due to the acid-accelerated hydrolysis of the ortho esters. The incubation stability of the acid-labile supramolecular aggregates in neutral buffer could be improved by incorporating hydrophobic poly(ε-caprolactone) into the core of the aggregates. PMID:25144934

  5. Vasoactivity of hydrogen sulfide in normoxic and anoxic turtles (Trachemys scripta)

    DEFF Research Database (Denmark)

    Stecyk, Jonathan A.W.; Jensen, Nini Skovgaard; Nilsson, Göran E.;

    2010-01-01

    Systemic vascular resistance (Rsys) of freshwater turtles increases substantially during anoxia, but the underlying mechanisms are not fully understood. We investigated whether hydrogen sulfide (H2S), an endogenously produced metabolite believed to be an O2 sensor/transducer of vasomotor tone...... of plasma acid-labile sulfide concentration, likely increased by 3- and 4-fold during anoxia at 21°C, and 5°C, respectively. Yet, blockade of endogenous H2S production by DL-propargylglycine or hydroxylamine (0.44 mmol/kg) partially reversed the decreased systemic conductance (Gsys) exhibited by 5°C anoxic...

  6. Structure and genetics of biosynthesis of the glycosyl phosphate-containing O-polysaccharide of Escherichia coli O160.

    Science.gov (United States)

    Perepelov, Andrei V; Guo, Xi; Senchenkova, Sof'ya N; Shashkov, Alexander S; Knirel, Yuriy A

    2015-11-19

    On mild acid degradation of the lipopolysaccharide of Escherichia coli O160, the O-polysaccharide was cleaved by acid-labile glycosyl phosphate linkages in the main chain. The resultant oligosaccharide and the alkali-treated lipopolysaccharide were studied by sugar analysis along with (1)H and (13)C NMR spectroscopies, and the following structure of the branched pentasaccharide repeating unit of the O-polysaccharide was established: The O-antigen gene cluster of E. coli O160 was found to be consistent with the O-polysaccharide structure established.

  7. An Increase in Acid Resistance of Foot-and-Mouth Disease Virus Capsid Is Mediated by a Tyrosine Replacement of the VP2 Histidine Previously Associated with VP0 Cleavage

    OpenAIRE

    Vázquez-Calvo, Ángela; Caridi, Flavia; Sobrino, Francisco; Martín-Acebes, Miguel Ángel

    2014-01-01

    The foot-and-mouth disease virus (FMDV) capsid is highly acid labile, but introduction of amino acid replacements, including an N17D change in VP1, can increase its acid resistance. Using mutant VP1 N17D as a starting point, we isolated a virus with higher acid resistance carrying an additional replacement, VP2 H145Y, in a residue highly conserved among picornaviruses, which has been proposed to be responsible for VP0 cleavage. This mutant provides an example of the multifunctionality of pico...

  8. シカヨウ セッチャク システム ノ カイハツ ニ モトメル モノ

    OpenAIRE

    西谷, 佳浩; ニシタニ, ヨシヒロ; Nishitani, Yoshihiro

    2016-01-01

    Alan Boyde and his colleagues first described smear layers-covered dental hard tissues. Later, David Eick and his group examined smear layer-covered dentin and showed how acid-labile are smear layers. A superior bond strength has come to be provided for the resin-dentin interface in the current dental adhesive systems as a result that the acid-etching treatment for the enamel/dentin was examined to remove smear layers. Moreover, latest adhesive systems which gave top priority to convenience i...

  9. 歯科用接着システムの開発に求めるもの

    OpenAIRE

    西谷, 佳浩; ニシタニ, ヨシヒロ; Nishitani, Yoshihiro

    2016-01-01

    Alan Boyde and his colleagues first described smear layers-covered dental hard tissues. Later, David Eick and his group examined smear layer-covered dentin and showed how acid-labile are smear layers. A superior bond strength has come to be provided for the resin-dentin interface in the current dental adhesive systems as a result that the acid-etching treatment for the enamel/dentin was examined to remove smear layers. Moreover, latest adhesive systems which gave top priority to convenience i...

  10. 2-Phenyl-tetrahydropyrimidine-4(1H-ones – cyclic benzaldehyde aminals as precursors for functionalised β2-amino acids

    Directory of Open Access Journals (Sweden)

    Markus Nahrwold

    2009-09-01

    Full Text Available Novel procedures have been developed to condense benzaldehyde effectively with β-amino acid amides to cyclic benzyl aminals. Double carbamate protection of the heterocycle resulted in fully protected chiral β-alanine derivatives. These serve as universal precursors for the asymmetric synthesis of functionalised β2-amino acids containing acid-labile protected side chains. Diastereoselective alkylation of the tetrahydropyrimidinone is followed by a chemoselective two step degradation of the heterocycle to release the free β2-amino acid. In the course of this study, an L-asparagine derivative was condensed with benzaldehyde and subsequently converted to orthogonally protected (R-β2-homoaspartate.

  11. Protein-resistant polymer coatings obtained by matrix assisted pulsed laser evaporation

    Energy Technology Data Exchange (ETDEWEB)

    Rusen, L. [National Institute for Lasers, Plasma and Radiation Physics, 409 Atomistilor Street, PO Box MG-16, 077125, Magurele, Bucharest (Romania); Mustaciosu, C. [Horia Hulubei National Institute of Physics and Nuclear Engineering - IFIN HH, Magurele, Bucharest (Romania); Mitu, B.; Filipescu, M.; Dinescu, M. [National Institute for Lasers, Plasma and Radiation Physics, 409 Atomistilor Street, PO Box MG-16, 077125, Magurele, Bucharest (Romania); Dinca, V., E-mail: dinali@nipne.ro [National Institute for Lasers, Plasma and Radiation Physics, 409 Atomistilor Street, PO Box MG-16, 077125, Magurele, Bucharest (Romania)

    2013-08-01

    Adsorption of proteins and polysaccharides is known to facilitate microbial attachment and subsequent formation of biofilm on surfaces that ultimately results in its biofouling. Therefore, protein repellent modified surfaces are necessary to block the irreversible attachment of microorganisms. Within this context, the feasibility of using the Poly(ethylene glycol)-block-poly(ε-caprolactone) methyl ether (PEG-block-PCL Me) copolymer as potential protein-resistant coating was explored in this work. The films were deposited using Matrix Assisted Pulsed Laser Evaporation (MAPLE), a technique that allows good control of composition, thickness and homogeneity. The chemical and morphological characteristics of the films were examined using Fourier Transform Infrared Spectroscopy (FTIR), contact angle measurements and Atomic Force Microscopy (AFM). The FTIR data demonstrates that the functional groups in the MAPLE-deposited films remain intact, especially for fluences below 0.5 J cm{sup −2}. Optical Microscopy and AFM images show that the homogeneity and the roughness of the coatings are related to both laser parameters (fluence, number of pulses) and target composition. Protein adsorption tests were performed on the PEG-block-PCL Me copolymer coated glass and on bare glass surface as a control. The results show that the presence of copolymer as coating significantly reduces the adsorption of proteins.

  12. Preparation of composite poly(ether block amide) membrane for CO2 capture

    Institute of Scientific and Technical Information of China (English)

    Lianjun Wang; Yang Li; Shuguang Li; Pengfei Ji; Chengzhang Jiang

    2014-01-01

    In this study, a poly(ether block amide) (Pebax 1657) composite membrane applied for CO2 capture was prepared by coating Pebax 1657 solution on polyacrylonitrile (PAN) ultrafiltration membrane. Ethanol/water mixture was used as the solvent of Pebax and the effects of ethanol/water mass ratios and Pebax concentration on the permeation properties of composite membrane were studied. To enhance the com-posite membrane permeance, the gutter layer, made from reactive amino silicone crosslinking with polydimethylsiloxane (PDMS), was de-signed. The influence of crosslinking degree of the gutter layer on membrane performance was investigated. As a result, a Pebax/amino-PDMS/PAN multilayer membrane with hexane resistance was developed, showing CO2 permeance of 350 GPU and CO2/N2 selectivity over 50. The blend of polyethylene glycol dimethyl ether (PEG-DME) with Pebax as coating material was studied to further improve the membrane performance. After being combined with PEG-DME additive, CO2 permeance of the final Pebax-PEG-DME/amino-PDMS/PAN composite membrane reached 400 GPU above with CO2/N2 selectivity over 65.

  13. Miniaturizable Ion-Selective Arrays Based on Highly Stable Polymer Membranes for Biomedical Applications

    Science.gov (United States)

    Mir, Mònica; Lugo, Roberto; Tahirbegi, Islam Bogachan; Samitier, Josep

    2014-01-01

    Poly(vinylchloride) (PVC) is the most common polymer matrix used in the fabrication of ion-selective electrodes (ISEs). However, the surfaces of PVC-based sensors have been reported to show membrane instability. In an attempt to overcome this limitation, here we developed two alternative methods for the preparation of highly stable and robust ion-selective sensors. These platforms are based on the selective electropolymerization of poly(3,4-ethylenedioxythiophene) (PEDOT), where the sulfur atoms contained in the polymer covalently interact with the gold electrode, also permitting controlled selective attachment on a miniaturized electrode in an array format. This platform sensor was improved with the crosslinking of the membrane compounds with poly(ethyleneglycol) diglycidyl ether (PEG), thus also increasing the biocompatibility of the sensor. The resulting ISE membranes showed faster signal stabilization of the sensor response compared with that of the PVC matrix and also better reproducibility and stability, thus making these platforms highly suitable candidates for the manufacture of robust implantable sensors. PMID:24999717

  14. Multifunctional reduction-responsive SPIO&DOX-loaded PEGylated polymeric lipid vesicles for magnetic resonance imaging-guided drug delivery

    Science.gov (United States)

    Wang, Sheng; Yang, Weitao; Du, Hongli; Guo, Fangfang; Wang, Hanjie; Chang, Jin; Gong, Xiaoqun; Zhang, Bingbo

    2016-04-01

    Multifunctional superparamagnetic iron-oxide (SPIO)-based nanoparticles have been emerging as candidate nanosystems for cancer diagnosis and therapy. Here, we report the use of reduction- responsive SPIO/doxorubicin (DOX)-loaded poly(ethylene glycol) monomethyl ether (PEG)ylated polymeric lipid vesicles (SPIO&DOX-PPLVs) as a novel theranostic system for tumor magnetic resonance imaging (MRI) diagnosis and controlled drug delivery. These SPIO&DOX-PPLVs are composed of SPIOs that function as MR contrast agents for tumor enhancement and PPLVs as polymer matrices for encapsulating SPIO and antitumor drugs. The in vitro characterizations show that the SPIO&DOX-PPLVs have nanosized structures (˜80 nm), excellent colloidal stability, good biocompatibility, as well as T 2-weighted MRI capability with a relatively high T 2 relaxivity (r 2 = 213.82 mM-1 s-1). In vitro drug release studies reveal that the release rate of DOX from the SPIO&DOX-PPLVs is accelerated in the reduction environment. An in vitro cellular uptake study and an antitumor study show that the SPIO&DOX-PPLVs have magnetic targeting properties and effective antitumor activity. In vivo studies show the SPIO&DOX-PPLVs have excellent T 2-weighted tumor targeted MRI capability, image-guided drug delivery capability, and high antitumor effects. These results suggest that the SPIO&DOX-PPLVs are promising nanocarriers for MRI diagnosis and cancer therapy applications.

  15. Preparation of pH-sensitive amphiphilic block star polymers, their self-assembling characteristics and release behavior on encapsulated molecules

    KAUST Repository

    Song, Xiaowan

    2016-05-28

    Poly(ethylene glycol) (PEG), a polymer with excellent biocompatibility, was widely used to form nanoparticles for drug delivery applications. In this paper, based on PEG, a series of pH-sensitive amphiphilic block star polymers of poly(ethylene glycol)-block-poly(ethoxy ethyl glycidyl ether) (PEG-b-PEEGE) with different hydrophobic length were synthesized by living anionic ring-opening polymerization method. The products were characterized using 1H NMR and gel permeation chromatography. These copolymers could self-assemble in aqueous solution to form micellar structure with controlled morphologies. Transmission electron microscopy showed that the nanoparticles are spherical or rodlike with different hydrophilic mass fractions. The pH response of polymeric aggregates from PEG-b-PEEGE was detected by fluorescence probe technique at different pH. A pH-dependent release behavior was observed and pH-responsiveness of PEG-b-PEEGE was affected by the hydrophobic block length. These results demonstrated that star-shaped polymers (PEG-b-PEEGE) are attractive candidates as anticancer drug delivery carriers. © 2016 Springer-Verlag Berlin Heidelberg

  16. Polymer and surfactant-templated synthesis of hollow and porous ZnS nano- and microspheres in a spray pyrolysis reactor.

    Science.gov (United States)

    Sharma, Munish K; Rohani, Parham; Liu, Sha; Kaus, Mark; Swihart, Mark T

    2015-01-13

    Nanostructured zinc sulfide can provide unique photonic, electronic, and catalytic properties that are of interest for applications ranging from bioimaging to photocatalysis. Here we report an easily controllable continuous method to produce porous and hollow ZnS nano- and microspheres. We used poly(ethylene glycol) methyl ether (PEG), polyvinylpyrrolidone (PVP), ethylene oxide/propylene oxide block copolymer (Pluronic F-38), and cetyltrimethylammonium bromide (CTAB) as templates to synthesize ZnS nano- and microspheres with controlled internal morphology in a spray pyrolysis process, starting from an aqueous solution of chemical precursors and templating agents. Spherical particles were produced by droplet-to-particle conversion of droplets. Zinc acetate and thiourea, used here as precursors for ZnS, react in solution to form bis-thiourea zinc acetate (BTZA), which precipitates with the evaporation of solvent. Upon further heating, BTZA decomposes to yield ZnS. During solvent evaporation, PEG and Pluronic precipitate after BTZA, driving formation of a shell of ZnS and a hollow core. In contrast, PVP and CTAB interact strongly with BTZA and ZnS, such that the PVP and ZnS remain intermixed. After evaporation of solvent, the templating agents can be pyrolyzed at high temperature to leave behind porous or hollow ZnS microspheres composed of many much smaller nanocrystals. PMID:25547202

  17. Tuneable drug-loading capability of chitosan hydrogels with varied network architectures

    CERN Document Server

    Tronci, Giuseppe; Russell, Stephen J; Wood, David J; Akashi, Mitsuru

    2013-01-01

    Advanced bioactive systems with defined macroscopic properties and spatio-temporal sequestration of extracellular biomacromolecules are highly desirable for next generation therapeutics. Here, chitosan hydrogels were prepared with neutral or negatively-charged crosslinkers in order to promote selective electrostatic complexation with charged drugs. Chitosan (CT) was functionalised with varied dicarboxylic acids, such as tartaric acid (TA), poly(ethylene glycol) bis(carboxymethyl) ether (PEG), 1.4-Phenylenediacetic acid (4Ph) and 5-Sulfoisophthalic acid monosodium salt (PhS), whereby PhS was hypothesised to act as a simple mimetic of heparin. ATR FT-IR showed the presence of C=O amide I, N-H amide II and C=O ester bands, providing evidence of covalent network formation. The crosslinker content was reversely quantified by 1H-NMR on partially-degraded network oligomers, so that 18 mol% PhS was exemplarily determined. Swellability, compressability, material morphology, and drug-loading capability were successfull...

  18. Amphiphilic block copolymers bearing six-membered ortho ester ring in side chains as potential drug carriers: synthesis, characterization, and in vivo toxicity evaluation.

    Science.gov (United States)

    Luo, Shi; Tao, Yangyang; Tang, Rupei; Wang, Rui; Ji, Weihang; Wang, Chun; Zhao, Youliang

    2014-07-01

    A new type of amphiphilic block copolymers, poly(ethylene glycol)-block-poly(2-methyl-acrylicacid 2-methoxy-5-methyl-[1,3]dioxin-5-ylmethyl ester) (PEG-b-PMME), bearing acid-labile six-membered ortho ester rings in side chains was synthesized by reversible addition-fragmentation chain-transfer polymerization, and the influence of chain length of the hydrophobic PMME block on micelle properties was investigated. The PEG-b-PMME micelles were stable in aqueous buffer at physiological pH with a low critical micelle concentration. Nile Red as a model drug was encapsulated into the micelles to explore the release profiles. The Nile Red-loaded polymeric micelles showed rapid release of Nile Red in weakly acidic environments (pH 5) but slow release under physiological condition (pH 7.4), due to different hydrolysis rate of ortho ester side chains of PEG-b-PMME. The Paclitaxel (PTX)-loaded micelles retained potency in killing lung cancer cells (A549), compared with the free PTX. No obvious toxicity was found in vitro and in vivo after intraperitoneal injection of the micelles, which confirms that the PEG-b-PMME micelles with unique acid-labile characteristic have great potential as nano-scaled carriers for drug delivery.

  19. Stimuli-Responsive Liposomes for Controlled Drug Delivery

    KAUST Repository

    Li, Wengang

    2014-09-01

    Liposomes are promising drug delivery vesicles due to their biodegradibility, large volume and biocompatibility towards both hydrophilic and hydrophobic drugs. They suffer, however, from poor stability which limits their use in controlled delivery applications. Herein, a novel method was devised for modification of liposomes with small molecules, polymers or nanoparticles to afford stimuli responsive systems that release on demand and stay relatively stable in the absence of the trigger.. This dissertation discusses thermosensitive, pH sensitive, light sensitive and magnetically triggered liposomes that have been prepared for controlled drug delivery application. RAFT polymerization was utilized for the preparation of thermosensitive liposomes (Cholesterol-PNIPAm) and acid-labile liposomes (DOPE-PAA). With low Mw Cholesterol-PNIPAm, the thermosensitive liposomes proved to be effective for controlled release and decreased the cytotoxicity of PNIPAm by eliciting the polymer doses. By crosslinking the DOPE-PAA on liposome surface with acid-labile diamine linkers, DOPE-PAA liposomes were verified to be sensitive at low pH. The effects of polymer structures (linear or hyperbranched) have also been studied for the stability and release properties of liposomes. Finally, a dual-responsive Au@SPIO embedded liposome hybrid (ALHs) was prepared with light-induced “on-and-off” function by photo-thermal process (visible light) and instant release properties triggered by alternating magnetic field, respectively. The ALH system would be further applied into the cellular imaging field as MRI contrast agent.

  20. Golgi-mediated post-translational processing of secretory acid phosphatase by Leishmania donovani promastigotes.

    Science.gov (United States)

    Bates, P A; Hermes, I; Dwyer, D M

    1990-03-01

    Monensin, an inhibitor of Golgi function, was used to investigate the role of this cell compartment in the glycosylation of Leishmania donovani promastigote secretory acid phosphatase (EC 3.1.3.2). Monensin-treated cells demonstrated morphological changes in the Golgi complex and secreted enzyme with an altered electrophoretic mobility: two discrete bands of approximately 95 and 110 kDa were found, as compared to the heterodisperse nature of the enzyme from untreated controls. Chemical deglycosylation by mild acid hydrolysis resulted in a similar effect on the electrophoretic mobility of purified extracellular enzyme. Acid phosphatase was also treated with N-glycosidase F (EC 3.5.1.52) to remove N-linked oligosaccharides. The altered lectin-binding properties of the enzyme after these two treatments demonstrated that an unusual type of galactose-containing acid-labile carbohydrate was present in secretory acid phosphatase in addition to the N-linked oligosaccharides. Further, experiments with 32P-labelled enzyme indicated that phosphodiester bonds were the structural component responsible for the sensitivity of this carbohydrate to mild acid hydrolysis. Cumulatively, these results demonstrated that a novel form of Golgi-mediated posttranslational modification had occurred to the secretory acid phosphatase presumably by the addition of an acid-labile phosphoglycan. PMID:2320058

  1. The distribution of phosphorus in the root systems of the Proteaceae and the identification of their rhizosphere and rhizoplane fungi

    International Nuclear Information System (INIS)

    The soil mycoflora of an acidic sandy soil at Pella in S.W. Cape, South Africa, was determined by the soil plate technique. The fungal populations of the rhizosphere and rhizoplane of root systems of Hakea sericea and Leucospermum parile, members of the Proteaceae growing in the soil were isolated by the serial root washing technique. The root systems of H. sericea and L. parile supported a more varied mycoflora than the non-rhizosphere soil. Members of the Ascomycotina were restricted to the rhizosphere and rhizoplane region and were absent from the non-rhizosphere soil. Different forms of phosphorus (P) containing compounds were extracted and fractionated from proteoid and non-proteoid roots of H. sericea seedlings grown in P amended Clovelly sand. The main P fractions of both proteoid and non-proteoid roots were lipid-P and orthophosphate. The phosphorus 32 uptake of the roots were also investigated. An acid labile trichloracetic acid soluble BaCl2 precipitate was present. Polyacrylamide gel electrophoresis and paper chromatography of the phenol detergent extracts of the root systems of H. sericea and Leucadendron laureolum (Proteaceae) failed to detect polyphosphate. It is concluded that the acid labile trichloracetic acid soluble BaCl2 precipitate fraction extracted from the root systems of the Proteaceae is non-nucleotide ester-P

  2. Poly(ethylene glycol-cholesterol inhibits L-type Ca2+ channel currents and augments voltage-dependent inactivation in A7r5 cells.

    Directory of Open Access Journals (Sweden)

    Rikuo Ochi

    Full Text Available Cholesterol distributes at a high density in the membrane lipid raft and modulates ion channel currents. Poly(ethylene glycol cholesteryl ether (PEG-cholesterol is a nonionic amphipathic lipid consisting of lipophilic cholesterol and covalently bound hydrophilic PEG. PEG-cholesterol is used to formulate lipoplexes to transfect cultured cells, and liposomes for encapsulated drug delivery. PEG-cholesterol is dissolved in the external leaflet of the lipid bilayer, and expands it to flatten the caveolae and widen the gap between the two leaflets. We studied the effect of PEG-cholesterol on whole cell L-type Ca(2+ channel currents (I(Ca,L recorded from cultured A7r5 arterial smooth muscle cells. The pretreatment of cells with PEG-cholesterol decreased the density of ICa,L and augmented the voltage-dependent inactivation with acceleration of time course of inactivation and negative shift of steady-state inactivation curve. Methyl-β-cyclodextrin (MβCD is a cholesterol-binding oligosaccharide. The enrichment of cholesterol by the MβCD:cholesterol complex (cholesterol (MβCD caused inhibition of I(Ca,L but did not augment voltage-dependent inactivation. Incubation with MβCD increased I(Ca,L, slowed the time course of inactivation and shifted the inactivation curve to a positive direction. Additional pretreatment by a high concentration of MβCD of the cells initially pretreated with PEG-cholesterol, increased I(Ca,L to a greater level than the control, and removed the augmented voltage-dependent inactivation. Due to the enhancement of the voltage-dependent inactivation, PEG-cholesterol inhibited window I(Ca,L more strongly as compared with cholesterol (MβCD. Poly(ethylene glycol conferred to cholesterol the efficacy to induce sustained augmentation of voltage-dependent inactivation of I(Ca,L.

  3. Peptide-Decorated Gold Nanoparticles as Functional Nano-Capping Agent of Mesoporous Silica Container for Targeting Drug Delivery.

    Science.gov (United States)

    Chen, Ganchao; Xie, Yusheng; Peltier, Raoul; Lei, Haipeng; Wang, Ping; Chen, Jun; Hu, Yi; Wang, Feng; Yao, Xi; Sun, Hongyan

    2016-05-11

    A stimuli-responsive drug delivery system (DDS) with bioactive surface is constructed by end-capping mesoporous silica nanoparticles (MSNs) with functional peptide-coated gold nanoparticles (GNPs). MSNs are first functionalized with acid-labile α-amide-β-carboxyl groups to carry negative charges, and then capped with positively charged GNPs that are decorated with oligo-lysine-containing peptide. The resulting hybrid delivery system exhibits endo/lysosomal pH triggered drug release, and the incorporation of RGD peptide facilitates targeting delivery to αvβ3 integrin overexpressing cancer cells. The system can serve as a platform for preparing diversified multifunctional nanocomposites using various functional inorganic nanoparticles and bioactive peptides.

  4. Conjugation chemistry through acetals toward a dextran-based delivery system for controlled release of siRNA

    KAUST Repository

    Cui, Lina

    2012-09-26

    New conjugation chemistry for polysaccharides, exemplified by dextran, was developed to enable the attachment of therapeutic or other functional moieties to the polysaccharide through cleavable acetal linkages. The acid-lability of the acetal groups allows the release of therapeutics under acidic conditions, such as that of the endocytic compartments of cells, regenerating the original free polysaccharide in the end. The physical and chemical behavior of these acetal groups can be adjusted by modifying their stereoelectronic and steric properties, thereby providing materials with tunable degradation and release rates. We have applied this conjugation chemistry in the development of water-soluble siRNA carriers, namely acetal-linked amino-dextrans, with various amine structures attached through either slow- or fast-degrading acetal linker. The carriers with the best combination of amine moieties and structural composition of acetals showed high in vitro transfection efficiency and low cytotoxicity in the delivery of siRNA. © 2012 American Chemical Society.

  5. Peptide-Decorated Gold Nanoparticles as Functional Nano-Capping Agent of Mesoporous Silica Container for Targeting Drug Delivery.

    Science.gov (United States)

    Chen, Ganchao; Xie, Yusheng; Peltier, Raoul; Lei, Haipeng; Wang, Ping; Chen, Jun; Hu, Yi; Wang, Feng; Yao, Xi; Sun, Hongyan

    2016-05-11

    A stimuli-responsive drug delivery system (DDS) with bioactive surface is constructed by end-capping mesoporous silica nanoparticles (MSNs) with functional peptide-coated gold nanoparticles (GNPs). MSNs are first functionalized with acid-labile α-amide-β-carboxyl groups to carry negative charges, and then capped with positively charged GNPs that are decorated with oligo-lysine-containing peptide. The resulting hybrid delivery system exhibits endo/lysosomal pH triggered drug release, and the incorporation of RGD peptide facilitates targeting delivery to αvβ3 integrin overexpressing cancer cells. The system can serve as a platform for preparing diversified multifunctional nanocomposites using various functional inorganic nanoparticles and bioactive peptides. PMID:27102225

  6. Studies on flagellar shortening in Chlamydomonas reinhardtii

    International Nuclear Information System (INIS)

    Flagellar shortening of Chlamydomonas reinhardtii was promoted by sodium chloride, pyrophosphate (sodium, potassium and ammonium salts), EDTA and EGTA, succinate, citrate and oxalate (sodium salts), caffeine and aminophylline. Removal of calcium from the medium potentiated the effects of these agents in inducing shortening. Investigations of the release of phosphorylated compounds to the medium during pyrophosphate-induced flagellar shortening of cells pre-labelled with 32P, revealed an as yet unidentified 32P-labelled compound with distinct chromatographic properties. Chromatography and electrophoresis indicates that it is a small, highly polar molecule with a high charge to mass ratio, containing thermo- and acid-labile phosphate linkages. Investigations showed of the release of 35S-labelled protein to the medium from cells pre-labelled with 35S-sulfate showed that flagellated cells released two prominent polypeptides which comigrated with α- and β-flagellar tubulin on SDS polyacrylamide gel electrophoresis, while deflagellated cells did not

  7. Hmb(off/on) as a switchable thiol protecting group for native chemical ligation.

    Science.gov (United States)

    Qi, Yun-Kun; Tang, Shan; Huang, Yi-Chao; Pan, Man; Zheng, Ji-Shen; Liu, Lei

    2016-05-01

    A new thiol protecting group Hmb(off/on) is described, which has a switchable activity that may be useful in the chemical synthesis of proteins. When placed on the side chain of Cys, Cys(Hmb(off)) is stable to trifluoroacetic acid (TFA) in the process of solid-phase peptide synthesis. When Cys(Hmb(off)) is treated with neutral aqueous buffers, it is cleanly converted to acid-labile Cys(Hmb(on)), which can later be fully deprotected by TFA to generate free Cys. The utility of Cys(Hmb(off/on)) is demonstrated by the chemical synthesis of an erythropoietin segment, EPO[Cys(98)-Arg(166)]-OH through native chemical ligation. PMID:27102373

  8. Tagging the Untaggable: A Difluoroalkyl-Sulfinate Ketone-Based Reagent for Direct C-H Functionalization of Bioactive Heteroarenes.

    Science.gov (United States)

    Gnaim, Samer; Scomparin, Anna; Li, Xiuling; Baran, Phil S; Rader, Christoph; Satchi-Fainaro, Ronit; Shabat, Doron

    2016-09-21

    We have developed a new difluoroalkyl ketal sulfinate salt reagent suitable for direct derivatization of heteroarene C-H bonds. The reagent is capable of introducing a ketone functional group on heteroarene bioactive compounds via a one-pot reaction. Remarkably, in three examples the ketone analog and its parent drug had almost identical cytotoxicity. In a representative example, the ketone analog was bioconjugated with a delivery vehicle via an acid-labile semicarbazone linkage and with a photolabile protecting group to produce the corresponding prodrug. Controlled release of the drug-ketone analog was demonstrated in vitro for both systems. This study provides a general approach to obtain taggable ketone analogs directly from bioactive heteroarene compounds with limited options for conjugation. We anticipate that this sodium ketal-sulfinate reagent will be useful for derivatization of other heteroarene-based drugs to obtain ketone-taggable analogs with retained efficacy. PMID:27494153

  9. An experimental design approach to the chemical characterisation of pectin polysaccharides extracted from Cucumis melo Inodorus.

    Science.gov (United States)

    Denman, Laura J; Morris, Gordon A

    2015-03-01

    Extracted pectins have been utilised in a number of applications in both the food and pharmaceutical industries where they are generally used as gelling agents, thickeners and stabilisers, although a number of pectins have been shown to be bioactive. These functional properties will depend upon extraction conditions. A statistical experimental design approach was used to study the effects of extraction conditions pH, time and temperature on pectins extracted from Cucumis melo Inodorus. The results show that the chemical composition is very sensitive to these conditions and that this has a great influence on for example the degree of branching. Higher temperatures, lower pHs and longer extraction times lead to a loss of the more acid labile arabinofuranose residues present on the pectin side chain. The fitting of regression equations relating yield and composition to extraction conditions can therefore lead to tailor-made pectins for specific properties and/or applications.

  10. Purification, partial characterization and immunolocalization of a proteophosphoglycan secreted by Leishmania mexicana amastigotes.

    Science.gov (United States)

    Ilg, T; Stierhof, Y D; McConville, M J; Overath, P

    1995-02-01

    The intracellular amastigote form of the parasitic protozoon Leishmania mexicana expresses a high-molecular weight phosphoglycan, which is antigenically related to the surface glycolipid lipophosphoglycan and the secreted enzyme acid phosphatase of Leishmania promastigotes. This antigen was purified from a cell-free homogenate of infected mouse tissue and from amastigotes. Compositional and immunological analysis of the purified components indicate a proteophosphoglycan structure consisting of serine-rich polypeptide chains and mild acid-labile phosphooligosaccharides capped by mannooligosaccharides. Immunofluorescence and immunoelectron microscopy of parasitized mouse peritoneal macrophages and infected mouse tissue suggest that the proteophosphoglycan is secreted in large amounts by amastigotes via their flagellar pockets into the parasitophorous vacuoles of host cells. In some infected macrophages proteophosphoglycan is also located in vesicles apparently originating from the parasitophorous vacuole, which demonstrates redistribution of a secreted amastigote antigen in parasitized host cells. PMID:7774606

  11. The growth hormone (GH)-insulin-like growth factor axis during testosterone replacement therapy in GH-treated hypopituitary males

    DEFF Research Database (Denmark)

    Fisker, Sidse; Nørrelund, Helene; Juul, A;

    2001-01-01

    in relation to two testosterone injections. Mean baseline IGF-I levels were 352 +/- 135 microg/L, and they remained unaltered during the study period (analysis of variance (ANOVA), P = 0.88). Free IGF-I levels did not change either (ANOVA, P = 0.35). Serum IGF binding protein-3 (IGFBP-3) and acid......-labile subunit decreased (ANOVA, P = 0.04 and P = 0.02 respectively) but post hoc analysis did not reveal a particular difference between days. IGFBP-1 increased following testosterone administration (ANOVA, P = 0.05), whereas GH binding protein levels tended to decrease following testosterone administration...... (ANOVA, P = 0.08). Prostate-specific antigen tended slightly to increase after each testosterone injection (ANOVA, P = 0.08, post hoc, NS). We conclude that major changes in total IGF-I are not induced during conventional intramuscular testosterone replacement in GH-treated hypopituitary males...

  12. Quantitation of sulfate and thiosulfate in clinical samples by ion chromatography.

    Science.gov (United States)

    Cole, D E; Evrovski, J

    1997-11-21

    For assay of serum sulfate, quantitation by ion conductimetry after separation by anion-exchange chromatography is the method of choice. In comparison to classical barium precipitation methods, chromatographic methods demonstrate increased precision, specificity and sensitivity, and they may be superior to spectrophotometric methods that rely on organic cation precipitation of sulfate. The increased sensitivity and specificity, as well as the inherent capacity of chromatographic methods for simultaneous determination of other anions, has led to its increasing use in the determination of excreted sulfate in clinical profiles of urinary anion composition. Ion chromatography can also be used to quantitate free sulfate in other clinical samples, including cerebrospinal fluid, sweat, saliva, breast milk and human tissues. Finally, ion chromatography shows promise as a more precise and sensitive method for measurement of total acid-labile sulfoesters and thiosulfate.

  13. Formulation, Development and Evaluation of delayed release capsules of Duloxetine Hydrochloride made of different Enteric Polymers

    Directory of Open Access Journals (Sweden)

    Pallavi Yerramsetty

    2012-03-01

    Full Text Available Delayed release systems have acquired a centre stage in the arena of pharmaceutical research and development. The present study involves formulation and evaluation of Duloxetine Hydrochloride delayed release capsules. Duloxetine Hydrochloride is an acid labile drug. It degrades in the acidic environment of the stomach thus leading to therapeutic inefficacy. Therefore it is necessary to bypass the acidic pH of the stomach which can be achieved by formulating delayed release dosage form by using different enteric polymers. Protection of drug from acidic environment is done by coating the drug with enteric polymers by using suspension layering technique in Fluidized bed processor (FBP with different enteric polymers like HPMCAS (Hydroxy Propyl Methyl Cellulose Acetate Succinate, Acryl EZE and HPMCP (Hydroxy propyl methyl cellulose phthalate.The formulation (E12 of delayed release capsules of Duloxetine Hydrochloride containing HPMCP (HP-55: HP- 50 as enteric polymer can be taken as optimized

  14. Polysomnographic sleep, growth hormone insulin-like growth factor-I axis, leptin, and weight loss

    DEFF Research Database (Denmark)

    Rasmussen, Michael; Wildschiødtz, Gordon; Juul, Anders;

    2008-01-01

    compared with nonobese subjects After diet-induced weight loss the differences in GH, free IGF-I, and leptin were no longer present between previously obese and nonobese subjects, whereas a significant difference in sleep duration and total IGF-I levels persisted. Rapid eye movement (REM) sleep, non-REM......Short sleep appears to be strongly associated with obesity and altered metabolic function, and sleep and growth hormone (GH) secretion seems interlinked. In obesity, both the GH-insulin-like-growth-factor-I (GH-IGF-I) axis and sleep have been reported to be abnormal, however, no studies have...... investigated sleep in relation to the GH-IGF-I axis and weight loss in obese subjects. In this study polygraphic sleep recordings, 24-h GH release, 24-h leptin levels, free-IGF-I, total-IGF-I, IGF-binding protein-3 (IGFBP-3), acid-labile subunit (ALS), cortisol and insulin sensitivity were determined in six...

  15. Rational Design of a Carrier Protein for the Production of Recombinant Toxic Peptides in Escherichia coli

    Science.gov (United States)

    Pizzo, Elio; Varcamonti, Mario; Zanfardino, Anna; Sgambati, Valeria; Di Maro, Antimo; Carpentieri, Andrea; Izzo, Viviana; Di Donato, Alberto; Cafaro, Valeria; Notomista, Eugenio

    2016-01-01

    Commercial uses of bioactive peptides require low cost, effective methods for their production. We developed a new carrier protein for high yield production of recombinant peptides in Escherichia coli very well suited for the production of toxic peptides like antimicrobial peptides. GKY20, a short antimicrobial peptide derived from the C-terminus of human thrombin, was fused to the C-terminus of Onconase, a small ribonuclease (104 amino acids), which efficiently drove the peptide into inclusion bodies with very high expression levels (about 200–250 mg/L). After purification of the fusion protein by immobilized metal ion affinity chromatography, peptide was obtained by chemical cleavage in diluted acetic acid of an acid labile Asp-Pro sequence with more than 95% efficiency. To improve peptide purification, Onconase was mutated to eliminate all acid labile sequences thus reducing the release of unwanted peptides during the acid cleavage. Mutations were chosen to preserve the differential solubility of Onconase as function of pH, which allows its selective precipitation at neutral pH after the cleavage. The improved carrier allowed the production of 15–18 mg of recombinant peptide per liter of culture with 96–98% purity without the need of further chromatographic steps after the acid cleavage. The antimicrobial activity of the recombinant peptide, with an additional proline at the N-terminus, was tested on Gram-negative and Gram-positive strains and was found to be identical to that measured for synthetic GKY20. This finding suggests that N-terminal proline residue does not change the antimicrobial properties of recombinant (P)GKY20. The improved carrier, which does not contain cysteine and methionine residues, Asp-Pro and Asn-Gly sequences, is well suited for the production of peptides using any of the most popular chemical cleavage methods. PMID:26808536

  16. Rational Design of a Carrier Protein for the Production of Recombinant Toxic Peptides in Escherichia coli.

    Directory of Open Access Journals (Sweden)

    Katia Pane

    Full Text Available Commercial uses of bioactive peptides require low cost, effective methods for their production. We developed a new carrier protein for high yield production of recombinant peptides in Escherichia coli very well suited for the production of toxic peptides like antimicrobial peptides. GKY20, a short antimicrobial peptide derived from the C-terminus of human thrombin, was fused to the C-terminus of Onconase, a small ribonuclease (104 amino acids, which efficiently drove the peptide into inclusion bodies with very high expression levels (about 200-250 mg/L. After purification of the fusion protein by immobilized metal ion affinity chromatography, peptide was obtained by chemical cleavage in diluted acetic acid of an acid labile Asp-Pro sequence with more than 95% efficiency. To improve peptide purification, Onconase was mutated to eliminate all acid labile sequences thus reducing the release of unwanted peptides during the acid cleavage. Mutations were chosen to preserve the differential solubility of Onconase as function of pH, which allows its selective precipitation at neutral pH after the cleavage. The improved carrier allowed the production of 15-18 mg of recombinant peptide per liter of culture with 96-98% purity without the need of further chromatographic steps after the acid cleavage. The antimicrobial activity of the recombinant peptide, with an additional proline at the N-terminus, was tested on Gram-negative and Gram-positive strains and was found to be identical to that measured for synthetic GKY20. This finding suggests that N-terminal proline residue does not change the antimicrobial properties of recombinant (PGKY20. The improved carrier, which does not contain cysteine and methionine residues, Asp-Pro and Asn-Gly sequences, is well suited for the production of peptides using any of the most popular chemical cleavage methods.

  17. Rational Design of a Carrier Protein for the Production of Recombinant Toxic Peptides in Escherichia coli.

    Science.gov (United States)

    Pane, Katia; Durante, Lorenzo; Pizzo, Elio; Varcamonti, Mario; Zanfardino, Anna; Sgambati, Valeria; Di Maro, Antimo; Carpentieri, Andrea; Izzo, Viviana; Di Donato, Alberto; Cafaro, Valeria; Notomista, Eugenio

    2016-01-01

    Commercial uses of bioactive peptides require low cost, effective methods for their production. We developed a new carrier protein for high yield production of recombinant peptides in Escherichia coli very well suited for the production of toxic peptides like antimicrobial peptides. GKY20, a short antimicrobial peptide derived from the C-terminus of human thrombin, was fused to the C-terminus of Onconase, a small ribonuclease (104 amino acids), which efficiently drove the peptide into inclusion bodies with very high expression levels (about 200-250 mg/L). After purification of the fusion protein by immobilized metal ion affinity chromatography, peptide was obtained by chemical cleavage in diluted acetic acid of an acid labile Asp-Pro sequence with more than 95% efficiency. To improve peptide purification, Onconase was mutated to eliminate all acid labile sequences thus reducing the release of unwanted peptides during the acid cleavage. Mutations were chosen to preserve the differential solubility of Onconase as function of pH, which allows its selective precipitation at neutral pH after the cleavage. The improved carrier allowed the production of 15-18 mg of recombinant peptide per liter of culture with 96-98% purity without the need of further chromatographic steps after the acid cleavage. The antimicrobial activity of the recombinant peptide, with an additional proline at the N-terminus, was tested on Gram-negative and Gram-positive strains and was found to be identical to that measured for synthetic GKY20. This finding suggests that N-terminal proline residue does not change the antimicrobial properties of recombinant (P)GKY20. The improved carrier, which does not contain cysteine and methionine residues, Asp-Pro and Asn-Gly sequences, is well suited for the production of peptides using any of the most popular chemical cleavage methods. PMID:26808536

  18. Asp1 from Schizosaccharomyces pombe binds a [2Fe-2S](2+) cluster which inhibits inositol pyrophosphate 1-phosphatase activity.

    Science.gov (United States)

    Wang, Huanchen; Nair, Vasudha S; Holland, Ashley A; Capolicchio, Samanta; Jessen, Henning J; Johnson, Michael K; Shears, Stephen B

    2015-10-27

    Iron-sulfur (Fe-S) clusters are widely distributed protein cofactors that are vital to cellular biochemistry and the maintenance of bioenergetic homeostasis, but to our knowledge, they have never been identified in any phosphatase. Here, we describe an iron-sulfur cluster in Asp1, a dual-function kinase/phosphatase that regulates cell morphogenesis in Schizosaccharomyces pombe. Full-length Asp1, and its phosphatase domain (Asp1(371-920)), were each heterologously expressed in Escherichia coli. The phosphatase activity is exquisitely specific: it hydrolyzes the 1-diphosphate from just two members of the inositol pyrophosphate (PP-InsP) signaling family, namely, 1-InsP7 and 1,5-InsP8. We demonstrate that Asp1 does not hydrolyze either InsP6, 2-InsP7, 3-InsP7, 4-InsP7, 5-InsP7, 6-InsP7, or 3,5-InsP8. We also recorded 1-phosphatase activity in a human homologue of Asp1, hPPIP5K1, which was heterologously expressed in Drosophila S3 cells with a biotinylated N-terminal tag, and then isolated from cell lysates with avidin beads. Purified, recombinant Asp1(371-920) contained iron and acid-labile sulfide, but the stoichiometry (0.8 atoms of each per protein molecule) indicates incomplete iron-sulfur cluster assembly. We reconstituted the Fe-S cluster in vitro under anaerobic conditions, which increased the stoichiometry to approximately 2 atoms of iron and acid-labile sulfide per Asp1 molecule. The presence of a [2Fe-2S](2+) cluster in Asp1(371-920) was demonstrated by UV-visible absorption, resonance Raman spectroscopy, and electron paramagnetic resonance spectroscopy. We determined that this [2Fe-2S](2+) cluster is unlikely to participate in redox chemistry, since it rapidly degraded upon reduction by dithionite. Biochemical and mutagenic studies demonstrated that the [2Fe-2S](2+) cluster substantially inhibits the phosphatase activity of Asp1, thereby increasing its net kinase activity. PMID:26422458

  19. PEG-b-PCL copolymer micelles with the ability of pH-controlled negative-to-positive charge reversal for intracellular delivery of doxorubicin.

    Science.gov (United States)

    Deng, Hongzhang; Liu, Jinjian; Zhao, Xuefei; Zhang, Yuming; Liu, Jianfeng; Xu, Shuxin; Deng, Liandong; Dong, Anjie; Zhang, Jianhua

    2014-11-10

    The application of PEG-b-PCL micelles was dampened by their inherent low drug-loading capability and relatively poor cell uptake efficiency. In this study, a series of novel PEG-b-PCL copolymers methoxy poly(ethylene glycol)-b-poly(ε-caprolactone-co-γ-dimethyl maleamidic acid -ε-caprolactone) (mPEG-b-P(CL-co-DCL)) bearing different amounts of acid-labile β-carboxylic amides on the polyester moiety were synthesized. The chain structure and chemical composition of copolymers were characterized by (1)H NMR, Fourier transform infrared spectroscopy (FT-IR), and gel permeation chromatography (GPC). mPEG-b-P(CL-co-DCL) with critical micellar concentrations (CMCs) of 3.2-6.3 μg/mL could self-assemble into stable micelles in water with diameters of 100 to 150 nm. Doxorubicin (DOX), a cationic hydrophobic drug, was successfully encapsulated into the polymer micelles, achieving a very high loading content due to electrostatic interaction. Then the stability, charge-conversional behavior, loading and release profiles, cellular uptake and in vitro cytotoxicity of free drug and drug-loaded micelles were evaluated. The β-carboxylic amides functionalized polymer micelles are negatively charged and stable in neutral solution but quickly become positively charged at pH 6.0, due to the hydrolysis of β-carboxylic amides in acidic conditions. The pH-triggered negative-to-positive charge reversal not only resulted in a very fast drug release in acidic conditions, but also effectively enhanced the cellular uptake by electrostatic absorptive endocytosis. The MTT assay demonstrated that mPEG-b-P(CL-co-DCL) micelles were biocompatible to HepG2 cells while DOX-loaded micelles showed significant cytotoxicity. In sum, the introduction of acid-labile β-carboxylic amides on the polyester block in mPEG-b-P(CL-co-DCL) exhibited great potentials for the modifications in the stability in blood circulation, drug solubilization, and release properties, as well as cell internalization and

  20. Doxorubicin conjugated functionalizable carbon dots for nucleus targeted delivery and enhanced therapeutic efficacy

    Science.gov (United States)

    Yang, Lei; Wang, Zheran; Wang, Ju; Jiang, Weihua; Jiang, Xuewei; Bai, Zhaoshi; He, Yunpeng; Jiang, Jianqi; Wang, Dongkai; Yang, Li

    2016-03-01

    Carbon dots (CDs) have shown great potential in imaging and drug/gene delivery applications. In this work, CDs functionalized with a nuclear localization signal peptide (NLS-CDs) were employed to transport doxorubicin (DOX) into cancer cells for enhanced antitumor activity. DOX was coupled to NLS-CDs (DOX-CDs) through an acid-labile hydrazone bond, which was cleavable in the weakly acidic intracellular compartments. The cytotoxicity of DOX-CD complexes was evaluated by the MTT assay and the cellular uptake was monitored using flow cytometry and confocal laser scanning microscopy. Cell imaging confirmed that DOX-CDs were mainly located in the nucleus. Furthermore, the complexes could efficiently induce apoptosis in human lung adenocarcinoma A549 cells. The in vivo therapeutic efficacy of DOX-CDs was investigated in an A549 xenograft nude mice model and the complexes exhibited an enhanced ability to inhibit tumor growth compared with free DOX. Thus, the DOX-CD conjugates may be exploited as promising drug delivery vehicles in cancer therapy.Carbon dots (CDs) have shown great potential in imaging and drug/gene delivery applications. In this work, CDs functionalized with a nuclear localization signal peptide (NLS-CDs) were employed to transport doxorubicin (DOX) into cancer cells for enhanced antitumor activity. DOX was coupled to NLS-CDs (DOX-CDs) through an acid-labile hydrazone bond, which was cleavable in the weakly acidic intracellular compartments. The cytotoxicity of DOX-CD complexes was evaluated by the MTT assay and the cellular uptake was monitored using flow cytometry and confocal laser scanning microscopy. Cell imaging confirmed that DOX-CDs were mainly located in the nucleus. Furthermore, the complexes could efficiently induce apoptosis in human lung adenocarcinoma A549 cells. The in vivo therapeutic efficacy of DOX-CDs was investigated in an A549 xenograft nude mice model and the complexes exhibited an enhanced ability to inhibit tumor growth compared

  1. Significance of abnormal serum binding of insulin-like growth factor II in the development of hypoglycemia in patients with non-islet-cell tumors

    International Nuclear Information System (INIS)

    The authors reported that serum and tumor from a hypoglycemic patient with a fibrosarcoma contained insulin-like growth factor II (IGF-II), mostly in a large molecular form designated big IGF-II. They now describe two additional patients with non-islet-cell tumor with hypoglycemia (NICTH) whose sera contained big IGF-II. Removal of the tumor eliminated most of the big IGF-II from the sera of two patients. Because specific IGF-binding proteins modify the bioactivity of IGFs, the sizes of the endogenous IGF-binding protein complexes were determined after neutral gel filtration through Sephadex G-200. Normally about 75% of IGFs are carried as a ternary complex of 150 kDa consisting of IGF, a growth hormone (GH)-dependent IGF-binding protein, and an acid-labile complexing component. The three patients with NICTH completely lacked the 150-kDa complex. IGF-II was present as a 60-kDa complex with variable contributions of smaller complexes. In the immediate postoperative period, a 110-kDa complex appeared rather than the expected 150-kDa complex. Abnormal IGF-II binding may be important in NICTH because the 150-kDa complexes cross the capillary membrane poorly. The smaller complexes present in our patients' sera would be expected to enter interstitial fluid readily, and a 4- to 5-fold increase in the fraction of IGFs reaching the target cells would result

  2. Significance of abnormal serum binding of insulin-like growth factor II in the development of hypoglycemia in patients with non-islet-cell tumors

    Energy Technology Data Exchange (ETDEWEB)

    Daughaday, W.H.; Kapadia, M. (Washington Univ. School of Medicine, St. Louis, MO (USA))

    1989-09-01

    The authors reported that serum and tumor from a hypoglycemic patient with a fibrosarcoma contained insulin-like growth factor II (IGF-II), mostly in a large molecular form designated big IGF-II. They now describe two additional patients with non-islet-cell tumor with hypoglycemia (NICTH) whose sera contained big IGF-II. Removal of the tumor eliminated most of the big IGF-II from the sera of two patients. Because specific IGF-binding proteins modify the bioactivity of IGFs, the sizes of the endogenous IGF-binding protein complexes were determined after neutral gel filtration through Sephadex G-200. Normally about 75% of IGFs are carried as a ternary complex of 150 kDa consisting of IGF, a growth hormone (GH)-dependent IGF-binding protein, and an acid-labile complexing component. The three patients with NICTH completely lacked the 150-kDa complex. IGF-II was present as a 60-kDa complex with variable contributions of smaller complexes. In the immediate postoperative period, a 110-kDa complex appeared rather than the expected 150-kDa complex. Abnormal IGF-II binding may be important in NICTH because the 150-kDa complexes cross the capillary membrane poorly. The smaller complexes present in our patients' sera would be expected to enter interstitial fluid readily, and a 4- to 5-fold increase in the fraction of IGFs reaching the target cells would result.

  3. Stimulated human neutrophils synthesize an ethanolamine plasmalogen analog of platelet-activating factor

    International Nuclear Information System (INIS)

    In addition to platelet-activating factor (PAF), human neutrophils stimulated by ionophore A23187 incorporate [3H] acetate into an additional product that migrates near phosphatidylethanolamine (PE) and accounts for approximately 25% of the labeled lipids. We have identified this product as 1-O-alk-1'-enyl-2-acetyl-sn-glycero-3-phosphoethanolamine based upon the following data. Acid lability of both the intact phospholipid and the diacetylglycerol derivates prepared by treatment of the intact product with phospholipase C followed by acetylation indicated approximately 80% of the unknown lipid is alk-1'-enyl-linked. Hydrogenation of the diacetyl derivative resulted in a product which no longer chromatographed by TLC with alk-1'-enyldiacetylglycerol, but rather with alkyldiacetylglycerol. The hydrogenated product was no longer sensitive to acid. Treatment with phospholipase A2 resulted in the release of 88% of the radiolabel into the acidified aqueous phase, indicating that the label remained as acetate. The head group was determined to be a primary amine based upon its complete conversion to the trinitrophenyl derivative by trinitrobenzenesulfonic acid. Investigations using a cell-free system indicate that neutrophils contain an acetyltransferase which, when stimulated, uses acetyl CoA and lysoPE plasmalogen to produce the ethanolamine plasmalogen analog of PAF

  4. Dioxin-like activity in sediments from Tai Lake, China determined by use of the H4IIE-luc bioassay and quantification of individual AhR agonists.

    Science.gov (United States)

    Xia, Jie; Su, Guanyong; Zhang, Xiaowei; Shi, Wei; Giesy, John P; Yu, Hongxia

    2014-01-01

    Deterioration of the general ecosystem and specifically quality of the water in Tai Lake (Ch: Taihu), the third largest freshwater in China, is of great concern. However, knowledge on status and trends of dioxin-like compounds in Tai Lake was limited. This study investigated AhR-mediated potency and quantified potential aryl hydrocarbon receptor (AhR) agonists in sediments from four regions (Meiliang Bay, Zhushan Lake, Lake Center, Corner of Zhushan Lake, and Meiliang Bay) of Tai Lake by use of the in vitro H4IIE-luc, cell-based, transactivation, reporter gene assay, and instrumental analysis. Concentrations of 2,3,7,8-tetrachlorodibenzo-p-dioxin equivalents (Bio-TEQs) in sediments ranged from less than the limit of detection to 114.5 pg/g, dry weight, which indicated that organic extracts of sediments exhibited significant AhR-mediated potencies. Results of the potency balance analysis demonstrated that acid-labile, dioxin-like compounds represented a greater proportion of concentrations of Bio-TEQs in sediments from Tai Lake. Concentrations of 2,3,7,8-tetrachlorodibenzo-p-dioxin equivalents calculated as the sum of the product of concentrations of individual congeners and their respective relative potencies (Chem-TEQs) based on polycyclic aromatic hydrocarbons and/or polychlorinated biphenyls represented no more than 10% of the total concentrations of Bio-TEQs. PMID:23925657

  5. A pH-sensitive hyaluronic acid prodrug modified with lactoferrin for glioma dual-targeted treatment.

    Science.gov (United States)

    Yin, Yatao; Fu, Chaoping; Li, Mei; Li, Xiangpen; Wang, Mengying; He, Lei; Zhang, Li-Ming; Peng, Ying

    2016-10-01

    Gliomas are the most common and lethal type of primary malignant brain tumor. But the existence of blood brain barrier (BBB) and blood-tumor barrier (BTB) hinder drug from reaching the tumor site. To address this problem, we developed a novel prodrug (Lf-HA-DOX) by conjugating hyaluronic acid with doxorubicin (HA-DOX) by an acid-labile hydrazone linkage, which is released in an acidic environment and accumulates in tumor tissues. Lactoferrin (Lf) was coupled for transporting across the BBB. In vitro, the release of DOX from Lf-HA-DOX was pH-dependent. At lower pH (5.0 and 6.0), the release of DOX was much quicker than that at pH7.4. In the cellular uptake studies, flow cytometry analyses and confocal laser scanning microscopy results showed significantly enhanced cellular uptake of Lf-HA-DOX and HA-DOX in C6 cells compared to DOX. In BALB/C mice bearing C6 glioma, enhanced accumulation of Lf-HA-DOX in the glioma was observed by real time fluorescence image. Correspondingly, glioma-bearing mice treated with Lf-HA-DOX displayed the longest median survival time, which was 2-fold longer than that of saline group. In conclusion, Lf-HA-DOX was able to significantly increase drug delivery to the glioma, which might provide a promising strategy for antiglioma therapy. PMID:27287110

  6. Mutations in pregnancy-associated plasma protein A2 cause short stature due to low IGF-I availability.

    Science.gov (United States)

    Dauber, Andrew; Muñoz-Calvo, María T; Barrios, Vicente; Domené, Horacio M; Kloverpris, Soren; Serra-Juhé, Clara; Desikan, Vardhini; Pozo, Jesús; Muzumdar, Radhika; Martos-Moreno, Gabriel Á; Hawkins, Federico; Jasper, Héctor G; Conover, Cheryl A; Frystyk, Jan; Yakar, Shoshana; Hwa, Vivian; Chowen, Julie A; Oxvig, Claus; Rosenfeld, Ron G; Pérez-Jurado, Luis A; Argente, Jesús

    2016-01-01

    Mutations in multiple genes of the growth hormone/IGF-I axis have been identified in syndromes marked by growth failure. However, no pathogenic human mutations have been reported in the six high-affinity IGF-binding proteins (IGFBPs) or their regulators, such as the metalloproteinase pregnancy-associated plasma protein A2 (PAPP-A2) that is hypothesized to increase IGF-I bioactivity by specific proteolytic cleavage of IGFBP-3 and -5. Multiple members of two unrelated families presented with progressive growth failure, moderate microcephaly, thin long bones, mildly decreased bone density and elevated circulating total IGF-I, IGFBP-3, and -5, acid labile subunit, and IGF-II concentrations. Two different homozygous mutations in PAPPA2, p.D643fs25* and p.Ala1033Val, were associated with this novel syndrome of growth failure. In vitro analysis of IGFBP cleavage demonstrated that both mutations cause a complete absence of PAPP-A2 proteolytic activity. Size-exclusion chromatography showed a significant increase in IGF-I bound in its ternary complex. Free IGF-I concentrations were decreased. These patients provide important insights into the regulation of longitudinal growth in humans, documenting the critical role of PAPP-A2 in releasing IGF-I from its BPs. PMID:26902202

  7. Stimulation of the 150-kilodalton insulin-like growth factor-binding protein-3 ternary complex by continuous and pulsatile patterns of growth hormone (GH) administration in GH-deficient patients

    DEFF Research Database (Denmark)

    Laursen, Torben; Flyvbjerg, Allan; Jørgensen, Jens Otto Lunde;

    2000-01-01

    Abstract In the circulation insulin-like growth factor I (IGF-I), IGF-binding protein 3 (IGFBP-3), and the acid-labile subunit (ALS) form a 150-kDa ternary complex that is of importance for the regulation of IGF-I bioactivity. GH administration is known to increase each of the single components of...... GH dose (2 IU/m2-24 h) was administered iv randomly as 1) continuous infusion or 2) eight bolus injections to five GH-deficient patients over a period of 24 h. GH administration significantly increased serum IGF-I and IGFBP-3 levels and the IGF-I/IGFBP-3 ratio. IGF-I levels increased most......, formation of the ternary complex was unaffected by the pattern of GH delivery. In conclusion, short-term GH administration increased all components of the 150-kDa ternary complex. Higher levels of IGF-I after constant GH exposure could indicate an increased bound fraction. However, the GH pattern did not...

  8. Formulation and evaluation of sustained release matrix tablet of rabeprazole using wet granulation technique

    Directory of Open Access Journals (Sweden)

    Ruqaiyah Khan

    2014-01-01

    Full Text Available Introduction: Rabeprazole, a member of substituted benzimidazoles, inhibits the final step in gastric acid secretions. This drug claims to cause fastest acid separation (due to higher pKa, and more rapidly converts to the active species to aid gastric mucin synthesis. The most significant pharmacological action of Rabeprazole is dose dependent suppression of gastric acid secretion; without anticholinergic or H2-blocking action. It completely abolishes the hydrochloric acid secretion as it is powerful inhibitor of gastric acid. Rabeprazole is acid labile and hence commonly formulated as an enteric coated tablet. The absorption of rabeprazole occurs rapidly as soon as tablet leaves the stomach. Aim: In the present study an attempt was made to formulate and evaluate Rabeprazole sustained release matrix tablet using wet granulation technique incorporating various polymers like HPMC-E15, Carbopol934, and sodium carboxymethyl cellulose (CMC. Materials and Methods: The Formulated tablets were evaluated for different physicochemical properties like rheological properties, weight variation, thickness, hardness, % friability, in vitro release studies and drug content. Results: Studies revealed that all the physicochemical parameters comply with the official standards. The in vitro release studies exhibits the release up to 90%, over a prolonged period of time which confirms the extended release profile of formulation, having better bioavailability as well as decreased dosing frequency with reduced doses. Conclusion: The sustained release matrix tablets of rabiprazole shown better bioavailability, efficacy and potency, when compared with official standards.

  9. Fluorescent polymeric assemblies as stimuli-responsive vehicles for drug controlled release and cell/tissue imaging

    International Nuclear Information System (INIS)

    Polymer assemblies with good biocompatibility, stimuli-responsive properties and clinical imaging capability are desirable carriers for future biomedical applications. Herein, we report on the synthesis of a novel anthracenecarboxaldehyde-decorated poly(N-(4-aminophenyl) methacryl amide-oligoethyleneglycolmonomethylether methacrylate) (P(MAAPAC-MAAP-MAPEG)) copolymer, comprising fluorescent chromophore and acid-labile moiety. This copolymer can assemble into micelles in aqueous solution and shows a spherical shape with well-defined particle size and narrow particle size distribution. The pH-responsive property of the micelles has been evaluated by the change of particle size and the controlled release of guest molecules. The intrinsic fluorescence property endows the micelles with excellent cell/tissue imaging capability. Cell viability evaluation with human hepatocellular carcinoma BEL-7402 cells demonstrates that the micelles are nontoxic. The cellular uptake of the micelles indicates a time-dependent behavior. The H22-tumor bearing mice treated with the micelles clearly exhibits the tumor accumulation. These multi-functional nanocarriers may be of great interest in the application of drug delivery. (paper)

  10. New complete genome sequences of human rhinoviruses shed light on their phylogeny and genomic features

    Directory of Open Access Journals (Sweden)

    Zdobnov Evgeny M

    2007-07-01

    Full Text Available Abstract Background Human rhinoviruses (HRV, the most frequent cause of respiratory infections, include 99 different serotypes segregating into two species, A and B. Rhinoviruses share extensive genomic sequence similarity with enteroviruses and both are part of the picornavirus family. Nevertheless they differ significantly at the phenotypic level. The lack of HRV full-length genome sequences and the absence of analysis comparing picornaviruses at the whole genome level limit our knowledge of the genomic features supporting these differences. Results Here we report complete genome sequences of 12 HRV-A and HRV-B serotypes, more than doubling the current number of available HRV sequences. The whole-genome maximum-likelihood phylogenetic analysis suggests that HRV-B and human enteroviruses (HEV diverged from the last common ancestor after their separation from HRV-A. On the other hand, compared to HEV, HRV-B are more related to HRV-A in the capsid and 3B-C regions. We also identified the presence of a 2C cis-acting replication element (cre in HRV-B that is not present in HRV-A, and that had been previously characterized only in HEV. In contrast to HEV viruses, HRV-A and HRV-B share also markedly lower GC content along the whole genome length. Conclusion Our findings provide basis to speculate about both the biological similarities and the differences (e.g. tissue tropism, temperature adaptation or acid lability of these three groups of viruses.

  11. Surface patterned pH-sensitive fluorescence using β-cyclodextrin functionalized poly(ethylene glycol).

    Science.gov (United States)

    Kim, Sung Han; Sharker, Shazid Md; In, Insik; Park, Sung Young

    2016-08-20

    This paper reports the development of a pH-responsive molecular pattern that shows specific and selective affinity for particular host-guest interactions, and its use as a pH fluorescent sensor. The pH-responsive boronate ester is formed via interactions between the diol group of β-cyclodextrin (CD) and phenylboronic acid of poly(ethylene glycol), and is strategically designed to allow reversible formation of a molecular lining pattern. Printing on a versatile substrate provides a method to monitor the positioning of different molecules by using a pH-responsive boronate ester, allowing specific host-guest interactions on any surface. Confocal laser scanning microscopy, fluorescence spectroscopy, and (1)H NMR results indicate that the assembled CD monolayer can be removed by washing with an acidic pH buffer, demonstrating the presence of a boronate ester connective bridge, which is acid labile. Therefore, visualization of the pH-responsive fluorescence sensor using a rhodamine-CD complex allows straightforward discrimination between different molecules on any substrate, thus facilitating application of this sensor in clinical diagnostics and environmental monitoring. PMID:27178950

  12. Organic Carbon Features Identified in the Nakhla Martian Meteorite

    Science.gov (United States)

    Mckay, D. S.; Thomas-Keprta, K. L.; Clemett, S. J.; Gibson, E. K., Jr.; Le, L.; Rahman, Z.; Wentworth, S. J.

    2011-01-01

    We report, for the first time, the identification of specific carbonaceous phases, present within iddingsite alteration zones of the Nakhla meteorite that possess discrete, well defined, structurally coherent morphologies. These structures bear superficial similarity to the carbonaceous nanoglobules [1] found in primitive chondrites interplanetary dust particles, although they are an order-of-magnitude larger in size. Introduction: It has been known for many years that some members of the Martian meteorite clan contain organic matter [e.g., 2-4]. Based on both isotopic measurements [5] and circumstantial observations [4] (e.g., the similarity organic signatures present in both Antarctic finds and non-Antarctic falls) a credible argument has been made for a preterrestrial origin for the majority of these organics. The Nakhla meteorite is of particular interest in that it has been shown to contain both an acid-labile organic fraction as well as an acid-insoluble high molecular weight organic component [4]. Pyrolysis-gas chromatography-mass spectrometry of the latter component indicates it to be composed of aromatic and alkyl-aromatic functionalities bound into a macromolecule phase through ether linkages [4]. However, the spatial, textural and mineralogical associations of this carbonaceous macromolecular material have remained elusive [6].

  13. Proteomic analysis of the royal jelly and characterization of the functions of its derivation glands in the honeybee.

    Science.gov (United States)

    Fujita, Toshiyuki; Kozuka-Hata, Hiroko; Ao-Kondo, Hiroko; Kunieda, Takekazu; Oyama, Masaaki; Kubo, Takeo

    2013-01-01

    To identify candidate royal jelly (RJ) proteins that might affect the physiologic status of honeybee colony members, we used shotgun proteomics to comprehensively identify the RJ proteome as well as proteomes of the hypopharyngeal gland (HpG), postcerebral gland (PcG), and thoracic gland (TG), from which RJ proteins are assumed to be derived. We identified a total of 38 nonredundant RJ proteins, including 22 putative secretory proteins and Insulin-like growth factor-binding protein complex acid labile subunit. Among them, 9 proteins were newly identified from RJ. Comparison of the RJ proteome with the HpG, PcG, and TG proteomes revealed that 17 of the 22 putative secretory RJ proteins were derived from some of these glands, suggesting that the RJ proteome is a cocktail of proteins from these three glands. Furthermore, pathway analysis suggested that the HpG proteome represents the molecular basis of the extremely high protein-synthesizing ability, whereas the PcG proteome suggests that the PcG functions as a reservoir for the volatile compounds and a primer pheromone. Finally, to further characterize the possible total RJ proteome, we identified putative secretory proteins in the proteomes of these three glands. This will be useful for predicting novel RJ protein components in future studies. PMID:23157659

  14. Synthetic Peptide libraries for T-cell epitope identification.

    Science.gov (United States)

    Hiemstra, H S; Drijfhout, J W; Koning, F

    2000-01-01

    This chapter describes a methodology for elucidating immunogenic epitopes stimulatory for CD4(+) T-cell clones (Fig. 1). The methodology makes use of synthetic peptide libraries and must be regarded as an alternative to other approaches, such as peptide elution or the application of genetic libraries. The methodology only requires knowledge about the restriction element of the T-cell clone. The restriction element determines which major histocompatibility complex (MHC)-binding anchor motif must be built into the library peptides. A synthetic peptide library is prepared comprising approx 8 million peptides. The synthesis proceeds via a mix-and-split protocol using a solidphase approach on a hybrid resin (1,2). On a hybrid resin, most of the peptide material (84%) is attached via an acid-labile linker whereas the remaining part of the peptide material is acid-stable attached (3). During synthesis, resinbound peptides comprising 14 amino acid residues are produced, with each resin bead containing one unique peptide (4,5). The beads are split into 384 pools, with each pool containing 20,000 beads. From each pool, about 28% of the peptide material is cleaved from every bead. Subsequently, in the first screening round, the 384 pools, each containing 20,000 solubilized peptides, are tested in a proliferation assay with the T-cell clone. Fig. 1. Flow diagram of the complete procedure for the identification of T-cell epitopes using synthetic peptide libraries (1).

  15. Microwave-assisted solid-phase peptide synthesis of the 60-110 domain of human pleiotrophin on 2-chlorotrityl resin.

    Science.gov (United States)

    Friligou, Irene; Papadimitriou, Evangelia; Gatos, Dimitrios; Matsoukas, John; Tselios, Theodore

    2011-05-01

    A fast and efficient microwave-assisted solid phase peptide synthesis (MW-SPPS) of a 51mer peptide, the main heparin-binding site (60-110) of human pleiotrophin (hPTN), using 2-chlorotrityl chloride resin (CLTR-Cl) following the 9-fluorenylmethyloxycarbonyl/tert-butyl (Fmoc/tBu) methodology and with the standard N,N'-diisopropylcarbodiimide/1-hydroxybenzotriazole (DIC/HOBt) coupling reagents, is described. An MW-SPPS protocol was for the first time successfully applied to the acid labile CLTR-Cl for the faster synthesis of long peptides (51mer peptide) and with an enhanced purity in comparison to conventional SPPS protocols. The synthesis of such long peptides is not trivial and it is generally achieved by recombinant techniques. The desired linear peptide was obtained in only 30 h of total processing time and in 51% crude yield, in which 60% was the purified product obtained with 99.4% purity. The synthesized peptide was purified by reversed phase high performance liquid chromatography (RP-HPLC) and identified by electrospray ionization mass spectrometry (ESI-MS). Then, the regioselective formation of the two disulfide bridges of hPTN 60-110 was successfully achieved by a two-step procedure, involving an oxidative folding step in dimethylsulfoxide (DMSO) to form the Cys(77)-Cys(109) bond, followed by iodine oxidation to form the Cys(67)-Cys(99) bond. PMID:20872260

  16. Controlled Multi-functionalization Facilitates Targeted Delivery of Nanoparticles to Cancer Cells.

    Science.gov (United States)

    Hudlikar, Manish S; Li, Xiuru; Gagarinov, Ivan A; Kolishetti, Nagesh; Wolfert, Margreet A; Boons, Geert-Jan

    2016-01-22

    A major objective of nanomedicine is to combine in a controlled manner multiple functional entities into a single nanoscale device to target particles with great spatial precision, thereby increasing the selectivity and potency of therapeutic drugs. A multifunctional nanoparticle is described for controlled conjugation of a cytotoxic drug, a cancer cell targeting ligand, and an imaging moiety. The approach is based on the chemical synthesis of polyethylene glycol that at one end is modified by a thioctic acid for controlled attachment to a gold core. The other end of the PEG polymers is modified by a hydrazine, amine, or dibenzocyclooctynol moiety for conjugation with functional entities having a ketone, activated ester, or azide moiety, respectively. The conjugation approach allowed the controlled attachment of doxorubicin through an acid-labile hydrazone linkage, an Alexa Fluor dye through an amide bond, and a glycan-based ligand for the cell surface receptor CD22 of B-cells using strain promoted azide-alkyne cycloaddition. The incorporation of the ligand for CD22 led to rapid entry of the nanoparticle by receptor-mediated endocytosis. Covalent attachment of doxorubicin via hydrazone linkage caused pH-responsive intracellular release of doxorubicin and significantly enhanced the cytotoxicity of nanoparticles. A remarkable 60-fold enhancement in cytotoxicity of CD22 (+) lymphoma cells was observed compared to non- targeted nanoparticles. PMID:26683093

  17. Effect of weight loss on free insulin-like growth factor-I in obese women with hyposomatotropism

    DEFF Research Database (Denmark)

    Rasmussen, Michael H; Juul, Anders; Hilsted, J

    2007-01-01

    OBJECTIVE: It has been hypothesized that increased free insulin-like growth factor (IGF)-I levels generated from an increase in IGF-binding protein (IGFBP) protease activity could be the inhibitory mechanism for the decreased growth hormone (GH) secretion observed in obese subjects. RESEARCH...... METHODS AND PROCEDURES: In this study, we determined basal and 24-hour levels of free IGF-I and -II, total IGF-I and -II, IGFBP-1, as well as basal IGFBP-2, -3, and -4, acid-labile subunit (ALS), IGFBP-1, -2, and -3 protease activity, and 24-hour GH release in obese women before and after a diet...... obese and non-obese women. Eight of the 16 obese women achieved an average weight loss of 30+/-5 kg during 26 to 60 weeks of dieting. After the considerable weight loss, significant differences in free IGF-I, GH release, and IGFBP-1 and -2 levels were no longer present between previously obese and non...

  18. Assessment of pathogenicity of natural IGFALS gene variants by in silico bioinformatics tools and in vitro functional studies.

    Science.gov (United States)

    Martucci, Lucía C; Gutiérrez, Mariana L; Karabatas, Liliana M; Scaglia, Paula A; Rey, Rodolfo A; Domené, Horacio M; Jasper, Héctor G; Domené, Sabina

    2016-07-01

    Acid-labile subunit (ALS) is essential for stabilization of IGF-I and IGFBP-3 in ternary complexes within the vascular system. ALS deficient (ALS-D) patients and a subset of children with idiopathic short stature (ISS), presenting IGFALS gene variants, show variable degree of growth retardation associated to IGF-I and IGFBP-3 deficiencies. The aim of this study was to evaluate the potential pathogenicity of eleven IGFALS variants identified in ALS-D and ISS children using in silico and in vitro approaches. We were able to classify seven of these variants as pathogenic since they present impaired synthesis (p.Glu35Lysfs*87, p.Glu35Glyfs*17, p.Asn276Ser, p.Leu409Phe, p.Ser490Trp and p.Cys540Arg), or partial impairment of synthesis and lack of secretion (p.Leu213Phe). We also observed significant reduction of secreted protein for variants p.Ala330Asp, Ala475Val and p.Arg548Trp, while still retaining their ability to form ternary complexes. These findings provide an approach to test the pathogenicity of IGFALS gene variants. PMID:27018247

  19. Environmental quality in sediments of Cadiz and Algeciras Bays based on a weight of evidence approach (southern Spanish coast).

    Science.gov (United States)

    Usero, José Antonio; Rosado, Daniel; Usero, José; Morillo, José

    2016-09-15

    This research applies an integrated sediment quality assessment method using a weight of evidence approach to Cadiz and Algeciras Bays (southern Spain). The method is composed of several analyses (particle size profile, aqua regia extractable metals, acid labile metals, total organic carbon, toxicity bioassay with Photobacterium phosphoreum and macrobenthic community alteration). The proposed method provides a single result, the environmental degradation index (EDI). EDI defined samples as low degraded (outer areas of both bays) and moderately degraded (Inner Bay of Cadiz Bay, the surroundings of Algeciras port and the northern part of Algeciras Bay). These samples showed the highest concentration of aqua regia extractable metals, which exceeded effects range-low (ERL) for Zn (51-176mg/l), Cu (11-54mg/l), As (4.3-9.5mg/l), Hg (0.17-0.28mg/l), Ni (23-82mg/l), and. Cr (37-134mg/l). They also exceeded some quality criteria for total organic carbon (4.0-6.5%) and toxicity (120-240TU/g) and showed poor results for macrobenthic community. PMID:27371957

  20. Structure of the β-l-fucopyranosyl phosphate-containing O-specific polysaccharide of Escherichia coli O84.

    Science.gov (United States)

    Knirel, Yuriy A; Qian, Chengqian; Senchenkova, Sofya N; Guo, Xi; Shashkov, Alexander S; Chizhov, Alexander O; Perepelov, Andrei V; Liu, Bin

    2016-07-01

    Fine structure of the O-polysaccharide chain of the lipopolysaccharide (O-antigen) defines the serospecificity of bacterial cells, which is the basis for O-serotyping of medically and agriculturally important gram-negative bacteria including Escherichia coli. In order to obtain the O-polysaccharide for structural analysis, the lipopolysaccharide was isolated from cells of E. coli O84a by phenol/water extraction and degraded with mild acid. However, the O-polysaccharide was cleaved at a highly acid-labile β-l-fucopyranosyl phosphate (β-l-Fucp-1-P) linkage to give mainly a pentasaccharide that corresponded to the O-polysaccharide repeat. Therefore, the lipopolysaccharide and the pentasaccharide as well as their O-deacylated derivatives were studied using sugar analysis, NMR spectroscopy, and (for oligosaccharides) ESI HR MS, and the O84-polysaccharide structure was established. The O-polysaccharide is distinguished by the presence of β-l-Fucp-1-P and randomly di-O-acetylated 6-deoxy-d-talose, which are found for the first time in natural carbohydrates. The gene cluster for the O84-antigen biosynthesis was analysed and its content was found to be consistent with the O-polysaccharide structure. PMID:27083849

  1. Interferon response in normal and Aleutian disease virus-infected mink.

    Science.gov (United States)

    Wiedbrauk, D L; Hadlow, W J; Ewalt, L C; Lodmell, D L

    1986-08-01

    Studies were done to determine whether differences in interferon production are responsible for the resistance of pastel mink to Aleutian disease. The abilities of normal pastel and sapphire mink to produce interferon when inoculated with either Newcastle disease virus or a synthetic polyribonucleotide, poly (I):poly (C), were identical, even to the production of a novel, acid-labile interferon. The resistance of pastel mink to Aleutian disease did not correlate with interferon production, because neither sapphire nor pastel mink produced detectable amounts of interferon when infected with either the Pullman strain of Aleutian disease virus (ADV) or the highly virulent Utah I strain. Sapphire mink infected with the Pullman strain responded normally to poly (I):poly (C) early in the course of the disease, but interferon production was impaired late, when the mink were hypergammaglobulinemic and had renal, vascular, and hepatic lesions. These data suggest that ADV Pullman neither stimulates nor interferes with interferon production in infected mink and may represent a mechanism whereby ADV can more readily establish infection.

  2. Mid-trimester maternal ADAM12 levels differ according to fetal gender in pregnancies complicated by preeclampsia.

    Science.gov (United States)

    Myers, Jenny E; Thomas, Grégoire; Tuytten, Robin; Van Herrewege, Yven; Djiokep, Raoul O; Roberts, Claire T; Kenny, Louise C; Simpson, Nigel A B; North, Robyn A; Baker, Philip N

    2015-02-01

    An overrepresentation of adverse pregnancy outcomes has been observed in pregnancies associated with a male fetus. We investigated the association between fetal gender and candidate biomarkers for preeclampsia. Proteins were quantified in samples taken at 20 weeks from women recruited to the SCreening fOr Pregnancy Endpoints (SCOPE) study (preeclampsia n = 150; no preeclampsia n = 450). In contrast to placental growth factor, soluble endoglin, and insulin-like growth factor acid labile subunit, levels of metallopeptidase domain 12 (ADAM12) at 20 weeks were dependent on fetal gender in pregnancies complicated by preeclampsia, for male (n = 73) fetuses the multiples of the median (MoM; interquartile range [IQR] 1.1-1.5) was 1.3, whereas for female fetuses (n = 75) MoM was 1.1 (1.0-1.3); P preeclampsia using ADAM12 levels was improved for pregnancies associated with a male fetus (area under receiver-operator curve [AUC] 0.73 [95% confidence interval [CI] 0.67-0.80]) than that of a female fetus (AUC 0.62 [0.55-0.70]); P = .03. The data presented here fit a contemporary hypothesis that there is a difference between the genders in response to an adverse maternal environment and suggest that an alteration in ADAM12 may reflect an altered placental response in pregnancies subsequently complicated by preeclampsia.

  3. Pentaerythrityltetramine scaffolds for solid-phase combinatorial chemistry.

    Science.gov (United States)

    Virta, Pasi; Leppänen, Marika; Lönnberg, Harri

    2004-03-19

    Straightforward synthesis for two pentaerythrityltetramine precursors, 2,2-bis(azidomethyl)propane-1,3-diamine (1) and 2-[N-(allyloxycarbonyl)aminomethyl]-2-azidomethylpropane-1,3-diamine (2), has been described. Both propane-1,3-diamines have been attached by reductive amination to a solid-supported backbone amide linker derived from 4-(4-formyl-3,5-dimethoxyphenoxy)butyric acid. The presence of the two methoxy substituents on the linker is essential to avoid cross-linking between two linkers. The remaining free primary amino group of the propane-1,3-diamine moiety may then be selectively acylated with an appropriately protected amino acid using conventional N,N-dicyclohexylcarbodiimide/1-hydroxybenzotriazole (DCC/HOBt) activation without any interference by the secondary amino function. The latter group may be subsequently acylated by an anhydride method. Sequential reduction of the azido group and removal of the allyloxycarbonyl protection from 2 allow further coupling of two different amino acids, and hence, this handle may be utilized in construction of branched structures containing four different amino acids or peptides. Solid-supported 1 may, in turn, be used for the synthesis of similar constructs containing two identical branches. It is worth noting that no acid-labile protecting groups are required in this approach, and hence, this dimension may be saved for the cleavage of the linker. The applicability of the scaffolds to library synthesis has been demonstrated by preparation of 11 pentaerythrityl-branched tetra- and octapeptides.

  4. Functional roles and clinical values of insulin-like growth factor-binding protein-5 in different types of cancers

    Institute of Scientific and Technical Information of China (English)

    G(o)k(c)e Güllü; Sevgi Karabulut; Mustafa Akkiprik

    2012-01-01

    Insulin-like growth factor-binding proteins (IGFBPs) are critical regulators of the mitogenic activity of insulin-like growth factors (IGFs).IGFBP5,one of these IGFBPs,has special structural features,including a nuclear transport domain,heparin-binding motif,and IGF/extracellular matrix/acid-labile subunit-binding sites.Furthermore,IGFBP5 has several functional effects on carcinogenesis and even normal cell processes,such as cell growth,death,motility,and tissue remodeling.These biological effects are sometimes related with IGF (IGF-dependent effects) and sometimes not (IGF-independent effects).The functional role of IGFBP5 is most likely determined in a cell-type and tissue-type specific manner but also depends on cell context,especially in terms of the diversity of interacting proteins and the potential for nuclear localization.Clinical findings show that IGFBP5 has the potential to be a useful clinical biomarker for predicting response to therapy and clinical outcome of cancer patients.In this review,we summarize the functional diversity and clinical importance of IGFBP5 in different types of cancers.

  5. Fluorescent polymeric assemblies as stimuli-responsive vehicles for drug controlled release and cell/tissue imaging

    Science.gov (United States)

    Chang, Ying; Li, Yang; Yu, Shirong; Mao, Jie; Liu, Cheng; Li, Qi; Yuan, Conghui; He, Ning; Luo, Weiang; Dai, Lizong

    2015-01-01

    Polymer assemblies with good biocompatibility, stimuli-responsive properties and clinical imaging capability are desirable carriers for future biomedical applications. Herein, we report on the synthesis of a novel anthracenecarboxaldehyde-decorated poly(N-(4-aminophenyl) methacryl amide-oligoethyleneglycolmonomethylether methacrylate) (P(MAAPAC-MAAP-MAPEG)) copolymer, comprising fluorescent chromophore and acid-labile moiety. This copolymer can assemble into micelles in aqueous solution and shows a spherical shape with well-defined particle size and narrow particle size distribution. The pH-responsive property of the micelles has been evaluated by the change of particle size and the controlled release of guest molecules. The intrinsic fluorescence property endows the micelles with excellent cell/tissue imaging capability. Cell viability evaluation with human hepatocellular carcinoma BEL-7402 cells demonstrates that the micelles are nontoxic. The cellular uptake of the micelles indicates a time-dependent behavior. The H22-tumor bearing mice treated with the micelles clearly exhibits the tumor accumulation. These multi-functional nanocarriers may be of great interest in the application of drug delivery.

  6. Molecular fingerprinting of carbohydrate structure phenotypes of three porifera proteoglycan-like glyconectins.

    Science.gov (United States)

    Guerardel, Yann; Czeszak, Xavier; Sumanovski, Lazar T; Karamanos, Yannis; Popescu, Octavian; Strecker, Gerard; Misevic, Gradimir N

    2004-04-01

    Glyconectins (GNs) represent a new class of proteoglycan-like cell adhesion and recognition molecules found in several Porifera species. Physico-chemical properties of GN carbohydrate moieties, such as size, composition, and resistance to most glycosaminoglycan-degrading enzymes, distinguish them from any other type of known glycoproteins. The molecular mechanism of GN-mediated self/non-self discrimination function is based on highly species-specific and Ca(2+)-dependent GN to GN associations that approach the selectivity of the evolutionarily advanced immunoglobulin superfamily. Carbohydrates of glyconectins 1, 2, and 3 are essential for species-specific auto-aggregation properties in three respective Porifera species. To obtain a structural insight into the molecular mechanisms, we performed carbohydrate structural analyses of glyconectins isolated from the three sponge model systems, Microciona prolifera (GN1), Halichondria panicea (GN2), and Cliona celata (GN3). The glycan content of all three GNs ranged between 40 and 60% of their total mass. Our approach using sequential and selective chemical degradation of GN glycans and subsequent mass spectrometric and NMR analyses revealed that each glyconectin presents novel and highly species-specific carbohydrate sequences. All three GNs include distinct acid-resistant and acid-labile carbohydrate domains, the latter composed of novel repetitive units. We have sequenced four short sulfated and one pyruvilated unit in GN1, eight larger and branched pyruvilated oligosaccharides in GN2, which represent a heterogeneous but related family of structures, and four sulfated units in GN3.

  7. Towards practical Baeyer-Villiger-monooxygenases: design of cyclohexanone monooxygenase mutants with enhanced oxidative stability.

    Science.gov (United States)

    Opperman, Diederik J; Reetz, Manfred T

    2010-12-10

    Baeyer-Villiger monooxygenases (BVMOs) catalyze the conversion of ketones and cyclic ketones into esters and lactones, respectively. Cyclohexanone monooxygenase (CHMO) from Acinetobacter sp. NCIMB 9871 is known to show an impressive substrate scope as well as exquisite chemo-, regio-, and enantioselectivity in many cases. Large-scale synthetic applications of CHMO are hampered, however, by the instability of the enzyme. Oxidation of cysteine and methionine residues contributes to this instability. Designed mutations of all the methionine and cysteine residues in the CHMO wild type (WT) showed that the amino acids labile towards oxidation are mostly either surface-exposed or located within the active site, whereas the two methionine residues identified for thermostabilization are buried within the folded protein. Combinatorial mutations gave rise to two stabilized mutants with either oxidative or thermal stability, without compromising the activity or stereoselectivity of the enzyme. The most oxidatively stabilized mutant retained nearly 40 % of its activity after incubation with H(2)O(2) (0.2 M), whereas the wild-type enzyme's activity was completely abolished at concentrations as low as 5 mM H(2)O(2). We propose that oxidation-stable mutants might well be a "prerequisite" for thermostabilization, because laboratory-evolved thermostability in CHMO might be masked by a high degree of oxidation instability.

  8. The influence of gastric emptying kinetics on the drug release from enteric coated pellets in fasted state: an in vitro/in vivo correlation.

    Science.gov (United States)

    Stefanič, M; Locatelli, I; Vrečer, F; Sever, T; Mrhar, A; Bogataj, M

    2012-10-01

    The absorption and bioavailability of drugs can be substantially affected by the transit of dosage forms through the gastrointestinal (GI) tract. Gastric emptying is one of the most critical parameters contributing to this inter- and intra-individual GI transit variability. It is especially important for the delayed release dosage forms whose release depends on the local environment and begins when the dosage form passes pylorus and comes into contact with higher pH medium in small intestine. The purpose of our research work was to predict the in vivo dissolution from enteric coated pellets for population and establish a good in vitro/in vivo correlation (IVIVC) with mean in vivo absorption profiles, obtained in a pharmacokinetic study under fasting conditions. The dissolution tests were carried out on a USP 4 - flow-through cell with enteric coated pellets containing an acid-labile drug and formulated as orodispersible tablets. Using several residence times in an acidic medium, we simulated the gastric emptying of the pellets and the exposure of different fractions of the pellets to the gastric medium for different periods of time. The amount of drug released decreased with the increasing time of exposure to the acidic medium due to the drug's degradation. The mean in vivo dissolution profiles, which were predicted on the basis of experimentally determined dissolution profiles and mathematical model of pellets' gastric emptying, gave a very good IVIVC with the mean in vivo absorption profiles. PMID:22884655

  9. MitoNEET Is a Uniquely Folded 2Fe-2S Outer Mitochondrial Membrane Protein Stabilized By Pioglitazone

    Energy Technology Data Exchange (ETDEWEB)

    Paddock, M.L.; Wiley, S.E.; Axelrod, H.L.; Cohen, A.E.; Roy, M.; Abresch, E.C.; Capraro, D.; Murphy, A.N.; Nechushtai, R.; Dixon, J.E.; Jennings, P.A.; /UC, San Diego /SLAC, SSRL /Hebrew U.

    2007-10-19

    Iron-sulfur (Fe-S) proteins are key players in vital processes involving energy homeostasis and metabolism from the simplest to most complex organisms. We report a 1.5 Angstrom x-ray crystal structure of the first identified outer mitochondrial membrane Fe-S protein, mitoNEET. Two protomers intertwine to form a unique dimeric structure that constitutes a new fold to not only the {approx}650 reported Fe-S protein structures but also to all known proteins. We name this motif the NEET fold. The protomers form a two-domain structure: a {beta}-cap domain and a cluster-binding domain that coordinates two acid-labile 2Fe-2S clusters. Binding of pioglitazone, an insulin-sensitizing thiazolidinedione used in the treatment of type 2 diabetes, stabilizes the protein against 2Fe-2S cluster release. The biophysical properties of mitoNEET suggest that it may participate in a redox-sensitive signaling and/or in Fe-S cluster transfer.

  10. Cloning, expression, and purification of a highly immunogenic recombinant gonadotropin-releasing hormone (GnRH) chimeric peptide.

    Science.gov (United States)

    Xu, Jinshu; Zhu, Zheng; Duan, Peng; Li, Wenjia; Zhang, Yin; Wu, Jie; Hu, Zhuoyi; Roque, Rouel S; Liu, Jingjing

    2006-12-01

    To design an anti-gonadotropin-releasing hormone (GnRH) vaccine capable of eliciting strong immunogenicity, a gene fragment encoding a chimeric peptide was constructed using polymerase chain reaction and ligated into a novel expression vector for recombinant expression in a T7 RNA polymerase-based expression system. The chimeric peptide called GnRH3-hinge-MVP contained three linear repeats of GnRH (GnRH3), a fragment of the human IgG1 hinge region, and a T-cell epitope of measles virus protein (MVP). The expression plasmid contained the GnRH3-hinge-MVP construct ligated to its fusion partner (AnsB-C) via an unique acid labile Asp-Pro linker. The recombinant fusion protein was expressed in an inclusion body in Escherichia coli under IPTG or lactose induction and the target peptide was easily purified using washing of urea and ethanol precipitation. The target chimeric peptide was isolated from the fusion partner following acid hydrolysis and purified using DEAE-Sephacel chromatography. The purified GnRH3-hinge-MVP was determined to be highly homogeneous by IEF analysis and the N-terminal sequencing. Further, immunization of female mice with the recombinant chimeric peptide resulted in generation of high-titer antibodies specific for GnRH. The results showed that GnRH3-hinge-MVP could be considered as a candidate anti-GnRH vaccine. PMID:17064933

  11. Urea, glycolic acid, and glycerol in an organic residue produced by ultraviolet irradiation of interstellar/pre-cometary ice analogs.

    Science.gov (United States)

    Nuevo, Michel; Bredehöft, Jan Hendrik; Meierhenrich, Uwe J; d'Hendecourt, Louis; Thiemann, Wolfram H-P

    2010-03-01

    More than 50 stable organic molecules have been detected in the interstellar medium (ISM), from ground-based and onboard-satellite astronomical observations, in the gas and solid phases. Some of these organics may be prebiotic compounds that were delivered to early Earth by comets and meteorites and may have triggered the first chemical reactions involved in the origin of life. Ultraviolet irradiation of ices simulating photoprocesses of cold solid matter in astrophysical environments have shown that photochemistry can lead to the formation of amino acids and related compounds. In this work, we experimentally searched for other organic molecules of prebiotic interest, namely, oxidized acid labile compounds. In a setup that simulates conditions relevant to the ISM and Solar System icy bodies such as comets, a condensed CH(3)OH:NH(3) = 1:1 ice mixture was UV irradiated at approximately 80 K. The molecular constituents of the nonvolatile organic residue that remained at room temperature were separated by capillary gas chromatography and identified by mass spectrometry. Urea, glycolic acid, and glycerol were detected in this residue, as well as hydroxyacetamide, glycerolic acid, and glycerol amide. These organics are interesting target molecules to be searched for in space. Finally, tentative mechanisms of formation for these compounds under interstellar/pre-cometary conditions are proposed.

  12. Cell penetrating peptide-based polyplexes shelled with polysaccharide to improve stability and gene transfection

    Science.gov (United States)

    Li, Wenyu; Liu, Yajie; Du, Jianwei; Ren, Kefeng; Wang, Youxiang

    2015-04-01

    Cell-penetrating peptides (CPP) have been widely developed as a strategy to enhance cell penetrating ability and transfection. In this work, octa-arginine modified dextran gene vector with pH-sensitivity was developed via host-guest interactions. α-Cyclodextrin was modified with octa-arginine (CDR), which had excellent cell penetrating ability. Dextran was selected as a backbone and modified with azobenzene as guest units by acid-labile imine bonds (Az-I-Dex). The supramolecular polymer CDR/Az-I-Dex with high a C/A molar ratio (molar ratio of CD on CDR to Az on Az-I-Dex) was unfavorable for DNA condensation. The dextran shell of CDR/Az-I-Dex/DNA polyplexes improved the stability under physiological conditions. However, once treated with acetate buffer (pH 5.4) for 3 h, large aggregates formed rapidly due to the cleavage of the dextran shell. As expected, the vector had cell viability of 80% even when the CDR concentration increased to 100 μg mL-1. Moreover, due to the effective cellular uptake efficiency, CDR/Az-I-Dex/DNA polyplexes had 6-300 times higher transfection efficiency than CDR/DNA polyplexes. It was even higher than high molecular weight PLL-based polyplexes of HEK293 T cells. Importantly, chloroquine as an endosomal escape agent could not improve the transfection of CDR/Az-I-Dex/DNA polyplexes, which indicated that the CDR/Az-I-Dex supramolecular polymer had its own ability for endosomal escape. These results suggested that the CPP-based polyplexes shelled with polysaccharide can be promising non-viral gene delivery carriers.Cell-penetrating peptides (CPP) have been widely developed as a strategy to enhance cell penetrating ability and transfection. In this work, octa-arginine modified dextran gene vector with pH-sensitivity was developed via host-guest interactions. α-Cyclodextrin was modified with octa-arginine (CDR), which had excellent cell penetrating ability. Dextran was selected as a backbone and modified with azobenzene as guest units by acid-labile

  13. AS1411 aptamer and folic acid functionalized pH-responsive ATRP fabricated pPEGMA-PCL-pPEGMA polymeric nanoparticles for targeted drug delivery in cancer therapy.

    Science.gov (United States)

    Lale, Shantanu V; R G, Aswathy; Aravind, Athulya; Kumar, D Sakthi; Koul, Veena

    2014-05-12

    Nonspecificity and cardiotoxicity are the primary limitations of current doxorubicin chemotherapy. To minimize side effects and to enhance bioavailability of doxorubicin to cancer cells, a dual-targeted pH-sensitive biocompatible polymeric nanosystem was designed and developed. An ATRP-based biodegradable triblock copolymer, poly(poly(ethylene glycol) methacrylate)-poly(caprolactone)-poly(poly(ethylene glycol) methacrylate) (pPEGMA-PCL-pPEGMA), conjugated with doxorubicin via an acid-labile hydrazone bond was synthesized and characterized. Dual targeting was achieved by attaching folic acid and the AS1411 aptamer through EDC-NHS coupling. Nanoparticles of the functionalized triblock copolymer were prepared using the nanoprecipitation method, resulting in an average particle size of ∼140 nm. The biocompatibility of the nanoparticles was evaluated using MTT cytotoxicity assays, blood compatibility studies, and protein adsorption studies. In vitro drug release studies showed a higher cumulative doxorubicin release at pH 5.0 (∼70%) compared to pH 7.4 (∼25%) owing to the presence of the acid-sensitive hydrazone linkage. Dual targeting with folate and the AS1411 aptamer increased the cancer-targeting efficiency of the nanoparticles, resulting in enhanced cellular uptake (10- and 100-fold increase in uptake compared to single-targeted NPs and non-targeted NPs, respectively) and a higher payload of doxorubicin in epithelial cancer cell lines (MCF-7 and PANC-1), with subsequent higher apoptosis, whereas a normal (noncancerous) cell line (L929) was spared from the adverse effects of doxorubicin. The results indicate that the dual-targeted pH-sensitive biocompatible polymeric nanosystem can act as a potential drug delivery vehicle against various epithelial cancers such as those of the breast, ovary, pancreas, lung, and others. PMID:24689987

  14. Genetic factors associated with small for gestational age birth and the use of human growth hormone in treating the disorder.

    Science.gov (United States)

    Saenger, Paul; Reiter, Edward

    2012-05-15

    The term small for gestational age (SGA) refers to infants whose birth weights and/or lengths are at least two standard deviation (SD) units less than the mean for gestational age. This condition affects approximately 3%-10% of newborns. Causes for SGA birth include environmental factors, placental factors such as abnormal uteroplacental blood flow, and inherited genetic mutations. In the past two decades, an enhanced understanding of genetics has identified several potential causes for SGA. These include mutations that affect the growth hormone (GH)/insulin-like growth factor (IGF)-1 axis, including mutations in the IGF-1 gene and acid-labile subunit (ALS) deficiency. In addition, select polymorphisms observed in patients with SGA include those involved in genes associated with obesity, type 2 diabetes, hypertension, ischemic heart disease and deletion of exon 3 growth hormone receptor (d3-GHR) polymorphism. Uniparental disomy (UPD) and imprinting effects may also underlie some of the phenotypes observed in SGA individuals. The variety of genetic mutations associated with SGA births helps explain the diversity of phenotype characteristics, such as impaired motor or mental development, present in individuals with this disorder. Predicting the effectiveness of recombinant human GH (hGH) therapy for each type of mutation remains challenging. Factors affecting response to hGH therapy include the dose and method of hGH administration as well as the age of initiation of hGH therapy. This article reviews the results of these studies and summarizes the success of hGH therapy in treating this difficult and genetically heterogenous disorder.

  15. Genetic factors associated with small for gestational age birth and the use of human growth hormone in treating the disorder

    Directory of Open Access Journals (Sweden)

    Saenger Paul

    2012-05-01

    Full Text Available Abstract The term small for gestational age (SGA refers to infants whose birth weights and/or lengths are at least two standard deviation (SD units less than the mean for gestational age. This condition affects approximately 3%–10% of newborns. Causes for SGA birth include environmental factors, placental factors such as abnormal uteroplacental blood flow, and inherited genetic mutations. In the past two decades, an enhanced understanding of genetics has identified several potential causes for SGA. These include mutations that affect the growth hormone (GH/insulin-like growth factor (IGF-1 axis, including mutations in the IGF-1 gene and acid-labile subunit (ALS deficiency. In addition, select polymorphisms observed in patients with SGA include those involved in genes associated with obesity, type 2 diabetes, hypertension, ischemic heart disease and deletion of exon 3 growth hormone receptor (d3-GHR polymorphism. Uniparental disomy (UPD and imprinting effects may also underlie some of the phenotypes observed in SGA individuals. The variety of genetic mutations associated with SGA births helps explain the diversity of phenotype characteristics, such as impaired motor or mental development, present in individuals with this disorder. Predicting the effectiveness of recombinant human GH (hGH therapy for each type of mutation remains challenging. Factors affecting response to hGH therapy include the dose and method of hGH administration as well as the age of initiation of hGH therapy. This article reviews the results of these studies and summarizes the success of hGH therapy in treating this difficult and genetically heterogenous disorder.

  16. Comparison of alternative buffers for use with a new live oral cholera vaccine, Peru-15, in outpatient volunteers.

    Science.gov (United States)

    Sack, D A; Shimko, J; Sack, R B; Gomes, J G; MacLeod, K; O'Sullivan, D; Spriggs, D

    1997-06-01

    During development of Peru-15, a new live oral vaccine for cholera, the role of buffer needed to be evaluated. Generally, oral bacterial vaccines are acid labile and need to be administered by using a formulation which protects them from gastric acid. We compared three different buffers for use with Peru-15, including a standard bicarbonate-ascorbic acid buffer, Alka-Seltzer, and a new electrolyte-rice buffer, CeraVacx. Saline served as the control. Thirty-nine healthy adult volunteers received Peru-15 (10(8) CFU) with one of the three buffers or saline in a double-masked study. The volunteers were monitored for symptoms for 7 days after the dose, serum was tested for antibody responses by vibriocidal antibody and immunoglobulin G antitoxin enzyme-linked immunosorbent assays, and stool samples were tested for excretion of the vaccine strain. Side effects were minimal in all groups. All 30 volunteers who took Peru-15 with a buffer showed significant rises in vibriocidal antibody titer. The magnitude of the rises was higher in the CeraVacx group than in the other two buffer groups. Four of nine volunteers who took the vaccine with saline also showed increased titers, but they were lower than those in any of the three buffer groups. Excretion of the vaccine strain was similar in the buffer groups, but excretion was not associated with the magnitude of the vibriocidal responses. Excretion of Peru-15 was not detected in the saline group. We conclude that buffer does amplify the serological response to Peru-15 and that CeraVacx may provide benefits not provided by other buffers.

  17. cvhA Gene of Streptomyces hygroscopicus 10-22 Encodes a Negative Regulator for Mycelia Development

    Institute of Scientific and Technical Information of China (English)

    Heng-An WANG; Lei QIN; Ping LU; Zhi-Xuan PANG; Zi-Xin DENG; Guo-Ping ZHAO

    2006-01-01

    A five-gene cluster cvhABCDE was identified from Streptomyces hygroscopicus 10-22. As the first gene of this cluster, cvhA encoded a putative sensor histidine kinase with a predicted sensor domain consisting of two trans-membrane segments at the N-terminus and a conserved HATPase_c domain at the Cterminus. The C-terminus polypeptide of CvhA expressed in Escherichia coli was purified and shown to be autophosphorylated with [γ-32p]ATP in vitro. The phosphoryl group was acid-labile and basic-stable, which supported histidine as the phosphorylation residue. No obvious difference of mycelia development was observed between the null mutant of cvhA generated by targeted gene replacement and the wild-type parental strain 10-22 grown on solid soya flour medium with 2%-8% glucose or sucrose, but the cvhA mutant could form much more abundant aerial mycelia and spores than the wild-type strain on solid soya flour medium supplemented with 6%-8% mannitol, 6%-8% sorbitol, 4%-6% mannose, or 4%-6% fructose. This phenotype was complemented by the cloned wild-type cvhA gene, and no difference was observed for growth curves of the cvhA mutant and the wild strain in liquid minimal medium with the tested sugars at a concentration of 4%, 6% and 8%. We thus propose that CvhA is likely a sensor histidine kinase and negatively regulates the morphological differentiation in a sugar-dependent manner in S. hygroscopicus 10-22.

  18. Unbound (bioavailable IGF1 enhances somatic growth

    Directory of Open Access Journals (Sweden)

    Sebastien Elis

    2011-09-01

    Understanding insulin-like growth factor-1 (IGF1 biology is of particular importance because, apart from its role in mediating growth, it plays key roles in cellular transformation, organ regeneration, immune function, development of the musculoskeletal system and aging. IGF1 bioactivity is modulated by its binding to IGF-binding proteins (IGFBPs and the acid labile subunit (ALS, which are present in serum and tissues. To determine whether IGF1 binding to IGFBPs is necessary to facilitate normal growth and development, we used a gene-targeting approach and generated two novel knock-in mouse models of mutated IGF1, in which the native Igf1 gene was replaced by Des-Igf1 (KID mice or R3-Igf1 (KIR mice. The KID and KIR mutant proteins have reduced affinity for the IGFBPs, and therefore present as unbound IGF1, or ‘free IGF1’. We found that both KID and KIR mice have reduced serum IGF1 levels and a concomitant increase in serum growth hormone levels. Ternary complex formation of IGF1 with the IGFBPs and the ALS was markedly reduced in sera from KID and KIR mice compared with wild type. Both mutant mice showed increased body weight, body and bone lengths, and relative lean mass. We found selective organomegaly of the spleen, kidneys and uterus, enhanced mammary gland complexity, and increased skeletal acquisition. The KID and KIR models show unequivocally that IGF1-complex formation with the IGFBPs is fundamental for establishing normal body and organ size, and that uncontrolled IGF bioactivity could lead to pathological conditions.

  19. Anchor-linked intermediates in peptide amide synthesis are caused by dimeric anchors on the solid supports.

    Science.gov (United States)

    Flechsler, I; Beck-Sickinger, A G; Stephan, H; Sheppard, R; Jung, G

    1995-01-01

    Cleavage and kinetic studies have been carried out using commercially obtained H-Tyr(tBu)-5-(4'-aminomethyl-3',5'-dimethoxyphenoxy)valeric acid-TentaGelS (H-Tyr(tBu)-4-ADPV-TentaGelS) and H-Tyr (tBu)-4-ADPV-Ala-aminomethyl-resin (H-Tyr(tBu)-4-ADPV-AM-resin) prepared from commercially available resin and loaded with commercially available Fmoc-4-ADPV-OH amide anchor. Cleavage with pure trifluoroacetic acid (TFA) gave the intermediate H-Tyr-4-ADPV-NH2, which was then degraded to H-Tyr-NH2, and cleavage with TFA/dichloromethane (1:9) yielded H-Tyr-4-ADPV-NH2 which could be isolated in preparative amounts. Cleavage reactions with 15N-labelled H-Ala-4-ADPV-(15N)-Gly-AM-resin yielded the intermediate H-Ala-4-ADPV-NH2, which contained no 15N as demonstrated by 1H-NMR. The analysis of the commercial Fmoc-4-ADPV-OH amide anchor showed the presence of Fmoc-4-ADPV-4-ADPV-OH as an impurity in high amounts. This dimeric anchor molecule is the cause of formation of the anchor-linked peptide intermediate obtained during the cleavage from the resin. The particularly high acid-lability of the amide bond between the two ADPV moieties was utilized to synthesize sidechain and C-terminally 4-ADPV protected pentagastrin on a double-anchor resin, and to cleave it using 5% trifluoroacetic acid in dichloromethane. This method may offer a new way for the synthesis of protected peptide amides with improved solubility to be used in fragment condensation.

  20. The environmental behavior and chemical fate of energetic compounds (TNT, RDX, tetryl) in soil and plant systems

    Energy Technology Data Exchange (ETDEWEB)

    Cataldo, D.A.; Harvey, S.D.; Fellows, R.J.

    1993-06-01

    Munitions materials can accumulate or cycle in terrestrial environs at production and manufacturing facilities and thus pose potential heath and environmental concerns. To address questions related to food chain accumulation, the environmental behavior of energetic compounds (2,4,6-trinitrotoluene,TNT; hexahydro-1,3,5-trinitro-1,3,5-triazine, RDX; 2,4,6-trinitrophenylmethylnitramine, tetryl) was evaluated. Emphasis was placed on determining the potential for soil/plant transfer of munitions residues, translocation and distribution within the plant, the extent to which compounds were metabolized following accumulation, and the chemical nature and form of accumulated residues. Both TNT and tetryl undergo extensive chemical transformation in soil, forming aminodinitrotoluene isomers and N-methyl-2,4,6-trinitroaniline residues, respectively, along with a series of unknowns. After 60 days, only 30% of the amended TNT and 8% of the amended tetryl remained unchanged in the soil. In contrast, 78% of the soil-amended RDX remained unchanged after 60 days. After 60 days, plants grown in soils containing 10 ppm residues contained from 5 {mu}g TNT/g to 600 {mu}g RDX/G fresh wt. tissue. TNT and tetryl residues were primarily accumulated in roots (75%), while RDX was concentrated in leaves and seed. The principal transport form for TNT (root to shoot) was an acid labile conjugate of aminodinitrotoluene; RDX was transported unchanged. On accumulation in roots and leaves, highly polar and non-extractable TNT metabolites dominated, with the aminodinitrotoluene isomers accounting for less than 20% of the residues present. Only a few percent were present as the parent TNT. RDX was partitioned similarly to TNT, with 8 to 30% of the RDX appearing as polar metabolites, 20--50% as parent RDX, and the balance as non-extractable residues. Tetryl was metabolized to N-methyl-2,4,6-trinitroaniline and a variety of polar metabolites.

  1. The environmental behavior and chemical fate of energetic compounds (TNT, RDX, tetryl) in soil and plant systems

    International Nuclear Information System (INIS)

    Munitions materials can accumulate or cycle in terrestrial environs at production and manufacturing facilities and thus pose potential heath and environmental concerns. To address questions related to food chain accumulation, the environmental behavior of energetic compounds (2,4,6-trinitrotoluene,TNT; hexahydro-1,3,5-trinitro-1,3,5-triazine, RDX; 2,4,6-trinitrophenylmethylnitramine, tetryl) was evaluated. Emphasis was placed on determining the potential for soil/plant transfer of munitions residues, translocation and distribution within the plant, the extent to which compounds were metabolized following accumulation, and the chemical nature and form of accumulated residues. Both TNT and tetryl undergo extensive chemical transformation in soil, forming aminodinitrotoluene isomers and N-methyl-2,4,6-trinitroaniline residues, respectively, along with a series of unknowns. After 60 days, only 30% of the amended TNT and 8% of the amended tetryl remained unchanged in the soil. In contrast, 78% of the soil-amended RDX remained unchanged after 60 days. After 60 days, plants grown in soils containing 10 ppm residues contained from 5 μg TNT/g to 600 μg RDX/G fresh wt. tissue. TNT and tetryl residues were primarily accumulated in roots (75%), while RDX was concentrated in leaves and seed. The principal transport form for TNT (root to shoot) was an acid labile conjugate of aminodinitrotoluene; RDX was transported unchanged. On accumulation in roots and leaves, highly polar and non-extractable TNT metabolites dominated, with the aminodinitrotoluene isomers accounting for less than 20% of the residues present. Only a few percent were present as the parent TNT. RDX was partitioned similarly to TNT, with 8 to 30% of the RDX appearing as polar metabolites, 20--50% as parent RDX, and the balance as non-extractable residues. Tetryl was metabolized to N-methyl-2,4,6-trinitroaniline and a variety of polar metabolites

  2. Development of phenylboronic acid-functionalized nanoparticles for emodin delivery

    Science.gov (United States)

    Wang, Bo; Chen, Limin; Sun, Yingjuan; Zhu, Youliang; Sun, Zhaoyan; An, Tiezhu; Li, Yuhua; Lin, Yuan; Fan, Daping; Wang, Qian

    2015-01-01

    Stable and monodisperse phenylboronic acid-functionalized nanoparticles (PBA-NPs) were fabricated using 3-((acrylamido)methyl)phenylboronic acid homopolymer (PBAH) via solvent displacement technique. The effect of operating parameters, including stirring time, initial polymer concentration and the proportion of methanol on the self-assembly process were systematically investigated. The diameters of the PBA-NPs were increased as increasing the initial PBAH concentration and the proportion of methanol. Likewise, there was a linear dependence between the size of self-assembled nanoparticles and the polymer concentration. Moreover, the dissipative particle dynamics (DPD) simulation technique was used to investigate the mechanism of self-assembly behavior of PBAH, which indicated that the interior of PBA-NPs was hydrophobic and compact, and the boronic acid groups were displayed on both the outermost and interior of PBA-NPs. The resulting PBA-NPs could successfully encapsulate emodin through PBA-diol interaction and the encapsulation efficiency (EE%) and drug loading content (DLC%) of drug-loaded PBA-NPs were 78% and 2.1%, respectively. Owing to the acid-labile feature of the boronate linkage, a reduction in environmental pH from pH 7.4 to 5.0 could trigger the disassociation of the boronate ester bonds, which could accelerate the drug release from PBA-Emodin-NPs. Besides, PBA-Emodin-NPs showed a much higher cytotoxicity to HepG2 cells (cancer cells) than that to MC-3T3-E1 cells (normal cells). These results imply that PBA-NPs would be a promising scaffold for the delivery of polyphenolic drugs. PMID:25960874

  3. Disulfiram/copper-disulfiram Damages Multiple Protein Degradation and Turnover Pathways and Cytotoxicity is Enhanced by Metformin in Oesophageal Squamous Cell Carcinoma Cell Lines.

    Science.gov (United States)

    Jivan, Rupal; Damelin, Leonard Howard; Birkhead, Monica; Rousseau, Amanda Louise; Veale, Robin Bruce; Mavri-Damelin, Demetra

    2015-10-01

    Disulfiram (DSF), used since the 1950s in the treatment of alcoholism, is reductively activated to diethyldithiocarbamate and both compounds are thiol-reactive and readily complex copper. More recently DSF and copper-DSF (Cu-DSF) have been found to exhibit potent anticancer activity. We have previously shown that the anti-diabetic drug metformin is anti-proliferative and induces an intracellular reducing environment in oesophageal squamous cell carcinoma (OSCC) cell lines. Based on these observations, we investigated the effects of Cu-DSF and DSF, with and without metformin, in this present study. We found that Cu-DSF and DSF caused considerable cytotoxicity across a panel of OSCC cells, and metformin significantly enhanced the effects of DSF. Elevated copper transport contributes to DSF and metformin-DSF-induced cytotoxicity since the cell-impermeable copper chelator, bathocuproinedisulfonic acid, partially reversed the cytotoxic effects of these drugs, and interestingly, metformin-treated OSCC cells contained higher intracellular copper levels. Furthermore, DSF may target cancer cells preferentially due to their high dependence on protein degradation/turnover pathways, and we found that metformin further enhances the role of DSF as a proteasome inhibitor. We hypothesized that the lysosome could be an additional, novel, target of DSF. Indeed, this acid-labile compound decreased lysosomal acidification, and DSF-metformin co-treatment interfered with the progression of autophagy in these cells. In summary, this is the first such report identifying the lysosome as a target of DSF and based on the considerable cytotoxic effects of DSF either alone or in the presence of metformin, in vitro, and we propose these as novel potential chemotherapeutic approaches for OSCC.

  4. Analysis of Bacterial Lipooligosaccharides by MALDI-TOF MS with Traveling Wave Ion Mobility

    Science.gov (United States)

    Phillips, Nancy J.; John, Constance M.; Jarvis, Gary A.

    2016-07-01

    Lipooligosaccharides (LOS) are major microbial virulence factors displayed on the outer membrane of rough-type Gram-negative bacteria. These amphipathic glycolipids are comprised of two domains, a core oligosaccharide linked to a lipid A moiety. Isolated LOS samples are generally heterogeneous mixtures of glycoforms, with structural variability in both domains. Traditionally, the oligosaccharide and lipid A components of LOS have been analyzed separately following mild acid hydrolysis, although important acid-labile moieties can be cleaved. Recently, an improved method was introduced for analysis of intact LOS by MALDI-TOF MS using a thin layer matrix composed of 2,4,6-trihydroxyacetophenone (THAP) and nitrocellulose. In addition to molecular ions, the spectra show in-source "prompt" fragments arising from regiospecific cleavage between the lipid A and oligosaccharide domains. Here, we demonstrate the use of traveling wave ion mobility spectrometry (TWIMS) for IMS-MS and IMS-MS/MS analyses of intact LOS from Neisseria spp. ionized by MALDI. Using IMS, the singly charged prompt fragments for the oligosaccharide and lipid A domains of LOS were readily separated into resolved ion plumes, permitting the extraction of specific subspectra, which led to increased confidence in assigning compositions and improved detection of less abundant ions. Moreover, IMS separation of precursor ions prior to collision-induced dissociation (CID) generated time-aligned, clean MS/MS spectra devoid of fragments from interfering species. Incorporating IMS into the profiling of intact LOS by MALDI-TOF MS exploits the unique domain structure of the molecule and offers a new means of extracting more detailed information from the analysis.

  5. Polyglycerol-coated nanodiamond as a macrophage-evading platform for selective drug delivery in cancer cells.

    Science.gov (United States)

    Zhao, Li; Xu, Yong-Hong; Akasaka, Tsukasa; Abe, Shigeaki; Komatsu, Naoki; Watari, Fumio; Chen, Xiao

    2014-07-01

    A successful targeted drug delivery device for cancer chemotherapy should ideally be able to avoid non-specific uptake by nonmalignant cells, particularly the scavenging monocyte-macrophage system as well as targeting efficacy to bring the drug preferentially into tumor cells. To this purpose, we developed a platform based on detonation nanodiamond (dND) with hyperbranched polyglycerol (PG) coating (dND-PG). dND-PG was first demonstrated to evade non-specific cell uptake, particularly by macrophages (U937). RGD targeting peptide was then conjugated to dND-PG through multistep organic transformations to yield dND-PG-RGD that still evaded macrophage uptake but was preferentially taken up by targeted A549 cancer cells (expressing RGD peptide receptors). dND-PG and dND-PG-RGD showed good aqueous solubility and cytocompatibitlity. Subsequently, the anticancer agent doxorubicin (DOX) was loaded through acid-labile hydrazone linkage to yield dND-PG-DOX and dND-PG-RGD-DOX. Their cellular uptake and cytotoxicity were compared against DOX in A549 cells and U937 macrophages. It was found that dND-PG-DOX uptake was substantially reduced, displaying little toxicity in either type of cells by virtue of PG coating, whereas dND-PG-RGD-DOX exerted selective toxicity to A549 cells over U937 macrophages that are otherwise highly sensitive to DOX. Finally, dND-PG was demonstrated to have little influence on U937 macrophage cell functions, except for a slight increase of TNF-α production in resting U937 macrophages. dND-PG is a promising drug carrier for realization of highly selective drug delivery in tumor cells through specific uptake mechanisms, with minimum uptake in and influence on macrophages. PMID:24720879

  6. Sunflower metallothionein family characterisation. Study of the Zn(II)- and Cd(II)-binding abilities of the HaMT1 and HaMT2 isoforms.

    Science.gov (United States)

    Tomas, M; Pagani, M A; Andreo, C S; Capdevila, M; Atrian, S; Bofill, R

    2015-07-01

    Plant metallothioneins (MTs) constitute a family of small Cys-rich proteins capable of coordinating metal ions, significantly differing from microbial and animal MTs. They are divided into four subfamilies depending on the Cys pattern in their sequence. In this work, the MT system of the sunflower plant (Helianthus annuus) has been defined, with ten genes coding for MTs (HaMT) belonging to the four plant MT subfamilies; three HaMT1, four HaMT2, one HaMT3 and two HaMT4 isoforms. The gene expression pattern and capacity to confer metal resistance to yeast cells have been analysed for at least one member of each subfamily. The divalent metal ion-binding abilities of HaMT1-2 and HaMT2-1 (the isoforms encoded by the most abundantly expressed HaMT1 and HaMT2 isogenes) have been characterised, as HaMT3 and HaMT4 were previously studied. Those isoforms constitute an optimum material to study the effect of Cys number variability on their coordination abilities, as they exhibit additional Cys residues regarding the canonical Cys pattern of each subfamily. Our results show that the variation in the number of Cys does not drastically modify their M(II)-binding abilities, but instead modulates the degree of heterogeneity of the corresponding recombinant syntheses. Significantly, the Zn(II)-HaMT1 complexes were highly susceptible to proteolytic cleavage. The recombinant Cd-MT preparations of both isoforms exhibit significant acid-labile sulphide content-Cd6S8 or Cd7S7 species. Overall results suggest that HaMT2-1 is probably associated with Cd(II) detoxification, in contrast to HaMT1-2, which may be more related to physiological functions, such as metal ion transport and delivery. PMID:25770010

  7. Structure of an Odorant-Vinding Protein form the Mosquito Aedes aegypti Suggests a Binding Pocket Covered by a pH-Sensitive

    Energy Technology Data Exchange (ETDEWEB)

    N Leite; R Krogh; W Xu; Y Ishida; J Iulek; W Leal; G Oliva

    2011-12-31

    The yellow fever mosquito, Aedes aegypti, is the primary vector for the viruses that cause yellow fever, mostly in tropical regions of Africa and in parts of South America, and human dengue, which infects 100 million people yearly in the tropics and subtropics. A better understanding of the structural biology of olfactory proteins may pave the way for the development of environmentally-friendly mosquito attractants and repellents, which may ultimately contribute to reduction of mosquito biting and disease transmission. Previously, we isolated and cloned a major, female-enriched odorant-binding protein (OBP) from the yellow fever mosquito, AaegOBP1, which was later inadvertently renamed AaegOBP39. We prepared recombinant samples of AaegOBP1 by using an expression system that allows proper formation of disulfide bridges and generates functional OBPs, which are indistinguishable from native OBPs. We crystallized AaegOBP1 and determined its three-dimensional structure at 1.85 {angstrom} resolution by molecular replacement based on the structure of the malaria mosquito OBP, AgamOBP1, the only mosquito OBP structure known to date. The structure of AaegOBP1 (= AaegOBP39) shares the common fold of insect OBPs with six {alpha}-helices knitted by three disulfide bonds. A long molecule of polyethylene glycol (PEG) was built into the electron-density maps identified in a long tunnel formed by a crystallographic dimer of AaegOBP1. Circular dichroism analysis indicated that delipidated AaegOBP1 undergoes a pH-dependent conformational change, which may lead to release of odorant at low pH (as in the environment in the vicinity of odorant receptors). A C-terminal loop covers the binding cavity and this 'lid' may be opened by disruption of an array of acid-labile hydrogen bonds thus explaining reduced or no binding affinity at low pH.

  8. Development of an Acid-Resistant Salmonella Typhi Ty21a Attenuated Vector For Improved Oral Vaccine Delivery

    Science.gov (United States)

    Feuille, Catherine M.; Starke, Carly Elizabeth C.; Bhagwat, Arvind A.; Stibitz, Scott; Kopecko, Dennis J.

    2016-01-01

    The licensed oral, live-attenuated bacterial vaccine for typhoid fever, Salmonella enterica serovar Typhi strain Ty21a, has also been utilized as a vaccine delivery platform for expression of diverse foreign antigens that stimulate protection against shigellosis, anthrax, plague, or human papilloma virus. However, Ty21a is acid-labile and, for effective oral immunization, stomach acidity has to be either neutralized with buffer or by-passed with Ty21a in an enteric-coated capsule (ECC). Several studies have shown that efficacy is reduced when Ty21a is administered in an ECC versus as a buffered liquid formulation, the former limiting exposure to GI tract lymphoid tissues. However, the ECC was selected as a more practical delivery format for both packaging/shipping and vaccine administration ease. We have sought to increase Ty21a acid-resistance to allow for removal from the ECC and immune enhancement. To improve Ty21a acid-resistance, glutamate-dependent acid resistance genes (GAD; responsible for Shigella spp. survival at very low pH) were cloned on a multi-copy plasmid (pGad) under a controllable arabinose-inducible promoter. pGad enhanced acid survival of Ty21a by 5 logs after 3 hours at pH 2.5, when cells were pre-grown in arabinose and under conditions that promote an acid-tolerance response (ATR). For genetically 100% stable expression, we inserted the gad genes into the Ty21a chromosome, using a method that allowed for subsequent removal of a selectable antibiotic resistance marker. Further, both bacterial growth curves and survival assays in cultured human monocytes/macrophages suggest that neither the genetic methods employed nor the resulting acid-resistance conferred by expression of the Gad proteins in Ty21a had any effect on the existing attenuation of this vaccine strain. PMID:27673328

  9. Type I and III IFNs Produced by Plasmacytoid Dendritic Cells in Response to a Member of the Flaviviridae Suppress Cellular Immune Responses.

    Science.gov (United States)

    Reid, Elizabeth; Juleff, Nicholas; Windsor, Miriam; Gubbins, Simon; Roberts, Lisa; Morgan, Sophie; Meyers, Gregor; Perez-Martin, Eva; Tchilian, Elma; Charleston, Bryan; Seago, Julian

    2016-05-15

    The pestivirus noncytopathic bovine viral diarrhea virus (BVDV) can suppress IFN production in the majority of cell types in vitro. However, IFN is detectable in serum during acute infection in vivo for ∼5-7 d, which correlates with a period of leucopoenia and immunosuppression. In this study, we demonstrate that a highly enriched population of bovine plasmacytoid dendritic cells (DCs) produced IFN in response to BVDV in vitro. We further show that the majority of the IFN produced in response to infection both in vitro and in vivo is type III IFN and acid labile. Further, we show IL-28B (IFN-λ3) mRNA is induced in this cell population in vitro. Supernatant from plasmacytoid DCs harvested postinfection with BVDV or recombinant bovine IFN-α or human IL-28B significantly reduced CD4(+) T cell proliferation induced by tubercle bacillus Ag 85-stimulated monocyte-derived DCs. Furthermore, these IFNs induced IFN-stimulated gene expression predominantly in monocyte-derived DCs. IFN-treated immature DCs derived from murine bone marrow also had a reduced capacity to stimulate T cell proliferative responses to tubercle bacillus Ag 85. Immature DCs derived from either source had a reduced capacity for Ag uptake following IFN treatment that is dose dependent. Immunosuppression is a feature of a number of pestivirus infections; our studies suggest type III IFN production plays a key role in the pathogenesis of this family of viruses. Overall, in a natural host, we have demonstrated a link between the induction of type I and III IFN after acute viral infection and transient immunosuppression. PMID:27053760

  10. Cloning, expression, and purification of a recombinant Tat-HA-NR2B9c peptide.

    Science.gov (United States)

    Zhou, Hai-Hui; Zhang, Ai-Xia; Zhang, Yu; Zhu, Dong-Ya

    2012-10-01

    To design a peptide disrupting the interaction between N-methyl-d-aspartate receptors-2B (NR2B) and postsynaptic density protein-95 (PSD-95), a gene fragment encoding a chimeric peptide was constructed using polymerase chain reaction and ligated into a novel expression vector for recombinant expression in a T7 RNA polymerase-based expression system. The chimeric peptide contained a fragment of the cell membrane transduction domain of the human immunodeficiency virus type1 (HIV-1) Tat, a influenza virus hemagglutinin (HA) epitope-tag, and the C-terminal 9 amino acids of NR2B (NR2B9c). We named the chimeric peptide Tat-HA-NR2B9c. The expression plasmid contained a gene fragment encoding the Tat-HA-NR2B9c was ligated to the C-terminal fragment of l-asparaginase (AnsB-C) via a unique acid labile Asp-Pro linker. The recombinant fusion protein was expressed in inclusion body in Escherichia coli under isopropyl β-d-1-thiogalactopyranoside (IPTG) and purified by washing with 2M urea, solubilizing in 4M urea, and then ethanol precipitation. The target chimeric peptide Tat-HA-NR2B9c was released from the fusion partner following acid hydrolysis and purified by isoelectric point precipitation and ultrafiltration. SDS-PAGE analysis and MALDI-TOF-MS analysis showed that the purified Tat-HA-NR2B9c was highly homogeneous. Furthermore, we investigated the effects of Tat-HA-NR2B9c on ischemia-induced cerebral injury in the rats subjected to middle cerebral artery occlusion (MCAO) and reperfusion, and found that the peptide reduced infarct size and improved neurological functions. PMID:22944204

  11. An alternative and expedient synthesis of radioiodinated 4-iodophenylalanine

    Energy Technology Data Exchange (ETDEWEB)

    Vaidyanathan, Ganesan, E-mail: ganesan.v@duke.edu [Department of Radiology, Box 3808, Duke University Medical Center, Durham, NC 27710 (United States); McDougald, Darryl; Grasfeder, Linda; Zalutsky, Michael R.; Chin, Bennett [Department of Radiology, Box 3808, Duke University Medical Center, Durham, NC 27710 (United States)

    2011-10-15

    Radiolabeled amino acids have been used extensively in oncology both as diagnostic and therapeutic agents. In our pursuit to develop radiopharmaceuticals to target breast cancer, we were interested in determining the uptake of radioiodinated 4-iodophenylalanine, among other labeled amino acids, in breast cancer cells. In this work, we have developed an alternative method for the synthesis of this agent. The novel tin precursor, (S)-tert-butyl 2-(tert-butoxycarbonylamino)-3-(4-(tributylstannyl)phenyl)propanoate (3) was synthesized from the known, corresponding iodo derivative. Initially, the labeled 4-iodophenylalanine was synthesized from the above tin precursor in two steps with radiochemical yields of 91.6{+-}2.7% and 83.7{+-}1.7% (n=5), for the radioiodination (first) and deprotection (second) step, respectively. Subsequently, it was synthesized in a single step with an average radiochemical yield of 94.8{+-}3.4% (n=5). After incubation with MCF-7 breast cancer cells for 60 min, an uptake of up to 49.0{+-}0.7% of the input dose was seen; in comparison, the uptake of [{sup 14}C]phenylalanine under the same conditions was 55.9{+-}0.5%. Furthermore, the uptake of both tracers was inhibited to a similar degree in a concentration-dependent manner by both unlabeled phenylalanine and 4-iodophenylalanine. With [{sup 14}C]phenylalanine as the tracer, IC{sub 50} values of 1.45 and 2.50 mM were obtained for Phe and I-Phe, respectively, and these values for [{sup 125}I]I-Phe inhibition were 1.3 and 1.0 mM. In conclusion, an improved and convenient method for the synthesis of no-carrier-added 4-[{sup *}I]phenylalanine was developed and the radiotracer prepared by this route demonstrated an amino acid transporter-mediated uptake in MCF-7 breast cancer cells in vitro that was comparable to that of [{sup 14}C]phenylalanine. - Highlights: > A new method to synthesize radioiodinated 4-iodophenylalanine. > Acid-labile protecting groups containing tin precursor. > Efficient removal

  12. Temporal variability of reactive iron over the Gulf of Alaska shelf

    Science.gov (United States)

    Aguilar-Islas, Ana M.; Séguret, Marie J. M.; Rember, Robert; Buck, Kristen N.; Proctor, Peter; Mordy, Calvin W.; Kachel, Nancy B.

    2016-10-01

    The Gulf of Alaska (GoA) shelf is a highly productive regime bordering the nitrate-rich, iron (Fe)-limited waters of the central GoA. The exchange between nitrate-limited, Fe-replete coastal waters and nitrate-rich, Fe-deplete offshore waters, amplified by mesoscale eddies, is key to the productivity of the region. Previous summer field studies have observed the partitioning of Fe in the coastal GoA as being heavily dominated by the particulate phase due to the high suspended particulate loads carried by glacial rivers into these coastal waters. Here we present new physico-chemical iron data and nutrient data from the continental shelf of the GoA during spring and late summer 2011. The late summer data along the Seward Line showed variable surface dissolved iron (DFe) concentrations (0.052 nM offshore to 4.87 nM inshore), within the range of previous observations. Relative to available surface nitrate, DFe was in excess (at Fe:C=50 μmol:mol) inshore, and deficient (at Fe:C=20 μmol:mol) offshore. Summer surface total dissolvable iron (TDFe, acidified unfiltered samples) was dominated by the acid-labile particulate fraction over the shelf (with a median contribution of only 3% by DFe), supporting previously observed Fe partitioning in the GoA. In contrast, our spring data from southeast GoA showed TDFe differently partitioned, with surface DFe (0.28-4.91 nM) accounting on average for a much higher fraction (~25%) of the TDFe pool. Spring surface DFe was insufficient relative to available nitrate over much of the surveyed region (at Fe:C=50 μmol:mol). Organic Fe-binding ligand data reveal excess concentrations of ligands in both spring and summer, indicating incomplete titration by Fe. Excess concentrations of an especially strong-binding ligand class in spring surface waters may reflect in-situ ligand production. Due to anomalous spring conditions in 2011, river flow and phytoplankton biomass during our spring sampling were lower than the expected May average. We

  13. Biological evaluation of protein nanocapsules containing doxorubicin

    Directory of Open Access Journals (Sweden)

    Toita R

    2013-05-01

    Full Text Available Riki Toita,1,2 Masaharu Murata,1–3 Kana Abe,3 Sayoko Narahara,1 Jing Shu Piao,2 Jeong-Hun Kang,4 Kenoki Ohuchida,2,5 Makoto Hashizume1–31Innovation Center for Medical Redox Navigation, Kyushu University, 2Department of Advanced Medical Initiatives, Kyushu University, 3Center for Advanced Medical Innovation, Kyushu University, Fukuoka, 4Department of Biomedical Engineering, National Cerebral and Cardiovascular Center Research Institutes, Suita, 5Department of Surgery and Oncology, Kyushu University, Fukuoka, JapanAbstract: This study describes the applications of a naturally occurring small heat shock protein (Hsp that forms a cage-like structure to act as a drug carrier. Mutant Hsp cages (HspG41C were expressed in Escherichia coli by substituting glycine 41 located inside the cage with a cysteine residue to allow conjugation with a fluorophore or a drug. The HspG41C cages were taken up by various cancer cell lines, mainly through clathrin-mediated endocytosis. The cages were detected in acidic organelles (endosomes/lysosomes for at least 48 hours, but none were detected in the mitochondria or nuclei. To generate HspG41C cages carrying doxorubicin (DOX, an anticancer agent, the HspG41C cages and DOX were conjugated using acid-labile hydrazone linkers. The release of DOX from HspG41C cages was accelerated at pH 5.0, but was negligible at pH 7.2. The cytotoxic effects of HspG41C–DOX against Suit-2 and HepG2 cells were slightly weaker than those of free DOX, but the effects were almost identical in Huh-7 cells. Considering the relatively low release of DOX from HspG41C–DOX, HspG41C–DOX exhibited comparable activity towards HepG2 and Suit-2 cells and slightly stronger cytotoxicity towards Huh-7 cells than free DOX. Hsp cages offer good biocompatibility, are easy to prepare, and are easy to modify; these properties facilitate their use as nanoplatforms in drug delivery systems and in other biomedical applications.Keywords: anticancer

  14. Engineering novel targeted nanoparticle formulations to increase the therapeutic efficacy of conventional chemotherapeutics against multiple myeloma

    Science.gov (United States)

    Ashley, Jonathan D.

    Multiple myeloma (MM) is a hematological malignancy which results from the uncontrolled clonal expansion of plasma cells within the body. Despite recent medical advances, this disease remains largely incurable, with a median survival of ˜7 years, owing to the development of drug resistance. This dissertation will explore new advances in nanotechnology that will combine the cytotoxic effects of small molecule chemotherapeutics with the tumor targeting capabilities of nanoparticles to create novel nanoparticle formulations that exhibit enhanced therapeutic indices in the treatment of MM. First, doxorubicin was surfaced conjugated onto micellar nanoparticles via an acid labile hydrazone bond to increase the drug accumulation at the tumor. The cell surface receptor Very Late Antigen-4 (VLA-4; alpha4beta1) is expressed on cancers of hematopoietic origin and plays a vital role in the cell adhesion mediated drug resistance (CAM-DR) in MM. Therefore, VLA-4 antagonist peptides were conjugated onto the nanoparticles via a multifaceted procedure to actively target MM cells and simultaneously inhibit CAM-DR. The micellar doxorubicin nanoparticles were able to overcome CAM-DR and demonstrated improved therapeutic index relative to free doxorubicin. In addition to doxorubicin, other classes of therapeutic agents, such as proteasome inhibitors, can be incorporated in nanoparticles for improved therapeutic outcomes. Utilizing boronic acid chemistry, bortezomib prodrugs were synthesized using a reversible boronic ester bond and then incorporated into liposomes. The different boronic ester bonds that could be potentially used in the synthesis of bortezomib prodrugs were screened based on stability using isobutylboronic acid. The liposomal bortezomib nanoparticles demonstrated significant proteasome inhibition and cytotoxicity in MM cells in vitro, and dramatically reduced the non-specific toxicities associated with free bortezomib while maintaining significant tumor growth

  15. In-situ nanochemistry for optoelectronics

    Science.gov (United States)

    Kim, Won Jin

    This thesis describes recent results on simple methods to arrange nanosize objects such as semiconductor nanocrystals, noble metal nanoparticles, and upconversion nanophosphors by means of top-down processes. Specific focus is directed towards approaches to produce predefined patterns of various nanostructure materials using optical lithography for direct writing of films for optoelectronic and electronic devices. To obtain photo-patternability, the nanostructure materials [for example semiconductor nanocrystals (CdSe, CdTe, PbSe), metallic nanoparticles (Ag), upconversion nanophosphors (Er3+/Yb 3+ or Tm3+/Yb3+ co-doped NaYF4 ), and transparent conducting oxide nanoparticles (ITO, ZnO)] were functionalized by incorporation of the functional ligand t-butoxycarbonyl (t-BOC) which has an acid-labile moiety. The t-BOC group undergoes a cleavage, when subjected to UV irradiation in the presence of a photo acid generator (PAG) to releases isobutene and carbon dioxide. Depending on the need of the application, either the exposed regions (negative pattern) or the non-exposed regions (positive pattern) could be developed from the exposed films by appropriate solvent selection. The photo exposed regions of the film are rendered hydrophilic due to the degradation of the t-BOC, the un-exposed regions remain hydrophobic. This solubility change in the QDs is the basis of their patternablity. The un-exposed regions can be removed to obtain the negative pattern by washing with hydrophobic solvents, whereas the exposed regions can be selectively removed to obtain positive pattern by washing with hydrophilic solvents. This change in the surface chemistry results in the ability to photo-pattern the various nanostructure materials where desired for a number of optoelectronic device geometries. We demonstrate that the ultimate resolution (linewidth and spacing) of this technique is below submicron. Details on technological aspects concerning nanoparticle patterning as well as practical

  16. 差别性释放两种药物的层层组装聚合物膜%Layer-by-layer Assembled Polymeric Films for Differential Release of Dual Drugs

    Institute of Scientific and Technical Information of China (English)

    陈栋栋; 陈杰; 田华雨; 陈学思; 孙俊奇

    2015-01-01

    基于层层组装技术制备了能够差别性释放2种药物的聚合物复合膜.通过大分子前体药物透明质酸-阿霉素( HA-DOX)与壳聚糖( HACC)的层层组装以及膜内后扩散负载甲氨喋呤二钠盐( MTX)的方法,实现了DOX和MTX 2种药物分子在聚合物膜中的负载. DOX和MTX在癌变组织的酸性环境下具有差别性的释放动力学, MTX在24 h内快速释放,而DOX长效缓释达10 d.细胞实验结果表明,差别性释放的DOX和MTX可有效地抑制癌细胞的增殖.%Layer-by-layer( LbL)-assembled polymeric films capable of differentially releasing dual anticancer drugs to achieve synergetic therapeutic effects were fabricated. Doxorubicin ( DOX ) was first conjugated to hyaluronic sodium( HA) via acid labile hydrazone bonds to produce HA-DOX prodrugs. Then HA-DOX was alternately deposited with 2-hydroxypropyltrimethyl ammonium chloride chitosan( HACC) to produce ( HACC/HA-DOX) n ( n is the number of deposition cycle ) film. Methotrexate ( MTX ) was then loaded into ( HACC/HA-DOX) 20 film by a post-diffusion process. MTX was quickly released due to the breakage of its electrostatic interaction with film component HACC. Meanwhile, DOX was released in a sustained manner because of the slow hydrolysis of hydrazine bonds. The synergetic therapeutic effects can be achieved by fast release of cell cycle specific drug MTX to effectively inhibit the proliferation of cancer cells and by sustained release of cell cycle non-specific drug DOX to kill cancer cells. The present study provides a new way for designing polymeric films for controlled release of multiple therapeutic agents.

  17. rhIGF-1 Therapy for Growth Failure and IGF-1 Deficiency in Congenital Disorder of Glycosylation Ia (PMM2 Deficiency

    Directory of Open Access Journals (Sweden)

    Bradley S. Miller MD, PhD

    2013-09-01

    Full Text Available Background. Congenital disorders of glycosylation (CDG are a group of rare disorders in which glycosylation required for proper protein-protein interactions and protein stability is disrupted, manifesting clinically with multiple system involvement and growth failure. The insulin-like growth factor (IGF system plays an important role in childhood growth and has been shown to be dysfunctional with low IGF-1 levels in children with CDG type Ia (PMM2 deficiency. Case report. A 3-year-old Caucasian male with failure to thrive was diagnosed with PMM2-CDG at 5 months of age. Initially, his length and weight were less than −2 standard deviation score, IGF-1 <25 ng/mL (normal 55-327 ng/mL, IGFBP-3 1.0 µg/mL (normal 0.7-3.6 ng/mL, and acid-labile subunit 1.3 mg/L (normal 0.7-7.9 mg/L. Despite aggressive feeding, he continued to show poor linear growth and weight gain. At 17 months, he underwent an IGF-1 generation test with growth hormone (0.1 mg/kg/d for 7 days; baseline IGF-1of 27 ng/mL (normal 55-327 ng/mL stimulated to only 33 ng/mL. Recombinant human IGF-1 (rhIGF-1 therapy (up to 130 µg/kg/dose twice daily was initiated at 21 months of age resulting in an excellent linear growth response with height increasing from −2.73 to −1.39 standard deviation score over 22 months. IGF-1 and IGFBP-3 levels also increased. Conclusion. This is the first case report of rhIGF-1 therapy in a patient with PMM2-CDG. The child had an excellent linear growth response. These results provide additional in vivo evidence for IGF dysfunction in PMM2-CDG and suggest that rhIGF-1 may be a novel treatment for growth failure in PMM2-CDG.

  18. Short stature associated with high circulating insulin-like growth factor (IGF)-binding protein-1 and low circulating IGF-II: effect of growth hormone therapy.

    Science.gov (United States)

    Barreca, A; Bozzola, M; Cesarone, A; Steenbergh, P H; Holthuizen, P E; Severi, F; Giordano, G; Minuto, F

    1998-10-01

    We report a case of short stature associated with high circulating levels of insulin-like growth factor (IGF)-binding protein-1 (IGFBP-10 and low levels of IGF-II responsive to pharmacological treatment with GH. Our patient suffered severe growth failure from birth (2.06 SD below the mean for normal full-term boys, and 5.2 and 7.3 SD below the mean at 5 and 10 months). Studies carried out before referral to our pediatric unit included normal 46,XY karyotype and normal encephalic imaging. Other endocrine and metabolic alterations and other systemic diseases were excluded. At 1.7 yr of age (length, 6.1 SD; weight, 4.6 SD; head circumference, 1.4 SD below the mean, respectively) the patient was referred to our pediatric unit. The baseline GH concentration was 31 microg/L, and the peak after an arginine load was 59.6 microg/L. In the same samples GH bioactivity was nearly superimposable (RIA/Nb2 bioactivity ratio = 0.9). Fasting insulin and glucose concentrations were 7.4 microU/mL and 65 mg/dL, respectively, both normally responsive to an oral glucose load. GH insensitivity was excluded by a basal IGF-I concentration (64 ng/mL) in the normal range for 0- to 5-yr-old boys and its increase after 2 IU/day hGH administration for 4 days. IGFBP-3 (0.5 microg/mL) was slightly reduced, whereas IGFBP-1 (2218 and 1515 ng/mL in two different basal samples) was well above the normal values for age and was suppressible by GH (maximum suppression, -77% at 84 h) and glucose load (maximum suppression, -46% at 150 min). The basal IGF-II concentration was below the normal range (86 ng/mL), whereas IGFBP-2 was normal (258 ng/mL). Analysis of the promoter region of IGFBP-1 and IGF-II failed to find major alterations. Neutral gel filtration of serum showed that almost all IGF-I activity was in the 35- to 45-kDa complex, coincident with IGFBP-1 peak, while the 150-kDa complex was absent, although the acid-labile subunit was normally represented. At 2.86 yr (height, 65.8 cm; height SD score

  19. 重组人源胰岛素原C肽在大肠杆菌中的克隆、表达与纯化%Cloning,expression and purification of recombinant human proinsulin C-peptide in E.coli

    Institute of Scientific and Technical Information of China (English)

    王学军; 顾凯; 曹荣月; 林洁; 吴洁; 刘景晶

    2006-01-01

    目的:构建一种新型表达载体(pEDCC),表达并纯化得到人源胰岛素原C肽.方法:将编码截短的门冬酰胺酶突变体(ansB-C),天然C肽,人IgG1铰链区(hinge),额外的酸敏感二肽(DP)以及富含碱性氨基酸的8肽(KRKRKKSR)的核苷酸序列依次分别插入pET28a载体中,构建表达载体pEDCC.在乳糖的诱导下,融合蛋白ansB-C-hinge-DPKRKRKKSRNGSGR-C-peptide以包涵体形式高效表达.融合蛋白经洗涤和乙醇分级沉淀纯化后,通过酸水解将PKRKRKKSRNGSGR-C-peptide释放出来.C肽N端14肽用胰蛋白酶切割,通过DE52柱与C-peptide分离.结果:构建的表达载体pEDCC序列正确,融合蛋白经分离纯化得到了高纯度的重组人源胰岛素原C肽.结论:以截短的门冬酰胺酶作为融合伙伴,并以富含碱性氨基酸的8肽调节等电点是一种生产重组人源胰岛素原C肽的有效方法.%Aim:To obtain recombinant human proinsulin C-peptide,a novel expression vector pEDCC was constructed to facilitate the expression and purification of C-peptide. Methods:Gene fragments encoding a truncated asparaginase fragment mutant,native C-peptide,a hinge fragment of human IgG1,an extra acid-labile dipeptide and a basic-amino-acid-riched octopeptide were introduced in turn into plasmid pET28a. The fusion protein ansB-C-hinge-DPKRKRKKSRNGSGR-C-peptide was expressed effectively as inclusion bodies after induced by lactose and partially purified by means of washing and ethanol fractionation. After being hydrolyzed,the polypeptide PKRKRKKSRNGSGR-C-peptide was liberated from the fusion partner. The N-terminal tetradecapeptide extension of C-peptide was subsequently cleaved by trypsin and removed by DE52 column. Results:The nucleotides sequence of plasmid pEDCC was confirmed to be identical with that of designed fusion protein. Recombinant human proinsulin C-peptide was obtained with high purity after purification. Conclusion:Employing truncated asparaginase as the fusion partner and basic

  20. Benzoyl-coenzyme A reductase (dearomatizing), a key enzyme of anaerobic aromatic metabolism. ATP dependence of the reaction, purification and some properties of the enzyme from Thauera aromatica strain K172.

    Science.gov (United States)

    Boll, M; Fuchs, G

    1995-12-15

    Anoxic metabolism of many aromatic compounds proceeds via the common intermediate benzoyl-CoA. Benzoyl-CoA is dearomatized by benzoyl-CoA reductase (dearomatizing) in a two-electron reduction step, possibly yielding cyclohex-1,5-diene-1-carboxyl-CoA. This process has to overcome a high activation energy and is considered a biological Birch reduction. The central, aromatic-ring-reducing enzyme was investigated for the first time in the denitrifying bacterium Thauera aromatica strain K172. A spectrophotometric assay was developed which was strictly dependent on MgATP, both with cell extract and with purified enzyme. The oxygen-sensitive new enzyme was purified 35-fold with 20% yield under anaerobic conditions in the presence of 0.25 mM dithionite. It had a native molecular mass of approximately 170 kDa and consisted of four subunits a,b,c,d of 48, 45, 38 and 32 kDa. The oligomer composition of the protein most likely is abcd. The ultraviolet/visible spectrum of the protein as isolated, but without dithionite, was characteristic for an iron-sulfur protein with an absorption maximum at 279 nm and a broad shoulder at 390 nm. The estimated molar absorption coefficient at 390 nm was 35,000 M-1 cm-1. Reduction of the enzyme by dithionite resulted in a decrease of absorbance at 390 nm, and the colour turned from greenish-brown to red-brown. The enzyme contained 10.8 +/- 1.5 mol Fe and 10.5 +/- 1.5 mol acid-labile sulfur/mol. Besides zinc (0.5 mol/mol protein) no other metals nor selenium could be detected in significant amounts. The enzyme preparation contained a flavin or flavin-like compound; the estimated content was 0.3 mol/mol enzyme. The enzyme reaction required MgATP and a strong reductant such as Ti(III). The reaction catalyzed is: benzoyl-CoA + 2 Ti(III) + n ATP-->non-aromatic acyl-CoA + 2 Ti(IV) + n ADP + n Pi. The estimated number n of ATP molecules hydrolyzed/two electrons transferred in benzoyl-CoA reduction is 2-4. In the absence of benzoyl-CoA the enzyme

  1. Proton pump inhibitor-associated pneumonia:Not a breath of fresh air after all?

    Institute of Scientific and Technical Information of China (English)

    Alexander; L; Fohl; Randolph; E; Regal

    2011-01-01

    Over the past two decades,proton pump inhibitors (PPIs)have emerged as highly effective and relatively safe agents for the treatment of a variety of gastrointestinal disorders.Unfortunately,this desirable pharmacological profile has also contributed to superfluous and widespread use in both the inpatient and outpatient settings.While generally well-tolerated,research published over the last decade has associated these agents with increased risks of Clostridium difficile disease, fractures likely due to calcium malabsorption and both community-acquired(CAP)and hospital-acquired pneumonias(HAP).The mechanism behind PPI-associated pneumonia may be multifactorial,but is thought to stem from compromising the stomach’s"acid mantle"against gastric colonization of acid-labile pathogenic bacteria which then may be aspirated.A secondary postulate is that PPIs,through their inhibition of extra-gastric H+/K+ATPase enzymes,may reduce the acidity of the upper aerodigestive tract,thus resulting in increased bacterial colonization of the larynx,esophagus and lungs.To date,several retrospective case control studies have been published looking at the association between PPI use and CAP.Some studies found a temporal relationship between PPI exposure and the incidence of pneumonia,but only two could define a dose-response re-lationship.Furthermore,other studies found an inverse correlation between duration of PPI use and risk of CAP. In terms of HAP,we reviewed two retrospective cohort studies and one prospective study.One retrospective study in a medical ICU found no increased association of HAP in PPI-exposed patients compared to no acid-lowering therapy,while the other in cardiothoracic surgery patients showed a markedly increased risk compared to those receiving H2RAs.The one prospective study in ICU patients showed an increased risk of HAP with PPIs, but not with H2RAs.In conclusion,the current literature shows a slight trend toward an association between PPI use and pneumonia

  2. Rapid, Efficient and Versatile Strategies for Functionally Sophisticated Polymers and Nanoparticles: Degradable Polyphosphoesters and Anisotropic Distribution of Chemical Functionalities

    Science.gov (United States)

    Zhang, Shiyi

    conjugate by densely attaching the polyphosphoester block with azide-functionalized Paclitaxel by azide-alkyne Huisgen cycloaddition. This Paclitaxel drug conjugate provides a powerful platform for combinational cancer therapy and bioimaging due to its ultra-high Paclitaxel loading (> 65 wt%), high water solubility (>6.2 mg/mL for PTX) and easy functionalization. Another polyphosphoester-based nanoparticle system has been developed by a programmable process for the rapid and facile preparation of a family of nanoparticles with different surface charges and functionalities. The non-ionic, anionic, cationic and zwitterionic nanoparticles with hydrodynamic diameters between 13 nm to 21 nm and great size uniformity could be rapidly prepared from small molecules in 6 h or 2 days. The anionic and zwitterionic nanoparticles were designed to load silver ions to treat pulmonary infections, while the cationic nanoparticles are being applied to regulate lung injuries by serving as a degradable iNOS inhibitor conjugates. In addition, a direct synthesis of acid-labile polyphosphoramidate by organobase-catalyzed ring-opening polymerization and an improved two-step preparation of polyphosphoester ionomer by acid-assisted cleavage of phosphoramidate bonds on polyphosphoramidate were developed. Polyphosphoramidate and polyphosphoester ionomers may be applied to many applications, due to their unique chemical and physical properties.

  3. lnteracciones de la respuesta del eje somatotrófco en la amenorrea hipotalámica funcional relacionada con la desnutrición The activity of the somatotrophic function in Functional Hypothalamic Amenorrhea (FHA related to undernourishmant

    Directory of Open Access Journals (Sweden)

    L Fiszlejder

    2011-03-01

    ólisis que aporta glucosa. No obstante, el aumento de los ácidos grasos libres y eventualmente la aparición de cuerpos cetónicos cuando la alimentación es muy restringida, sugieren la presencia de acidosis metabólica. Este estadio clínico implica un aumento del riesgo cardiovascular y la posibilidad de muerte prematura o súbita, una eventualidad latente en las pacientes con AHF y desnutridas. El autor declara no poseer conflictos de intereses.The activity of the somatotropic function in Functional Hypothalamic Amenorrhea (FHA is increased at the central level, and paradoxically, the peripheral hormonal behaviour, intermediate metabolism and several clinical aspects may be similar to those observed in somatotropic axis deficiency. Baseline and daily GH secretion levels are high, but its pulsatile profile is irregular. This results in resistance to GH, i.e., downregulation of hormone receptors, which, together with the decrease in GH binding protein (GHBP, impair GH ability to stimulate the synthesis of IGF-I, IGFBP-3 and the acid-labile subunit in the liver. This causes a decrease in the availability of free IGF-I in tissues. In addition, IGFBP-1 and IGF-BP2 significantly increase. Even if these peptides are regulated by GH, their inverse correlation with insulin activity (which is decreased in these patients and the low protein diet, respectively, appear to be more important factors. The increase in the serum levels of these peptides also contributes to the decrease in free IGF-I. Alterations in secretory patterns lead to a decrease in leptin concentration (an adipokine and to an increase in Ghrelin, which, in turn, facilitates GH secretion and has a remarkable incidence in intermediate metabolism in these undernourished patients. These hormonal changes can be interpreted as a mechanism of homeostatic adaptation tending to preserve availability of energetic nutrients. Thus, there is an initial predominance of lypolisis followed by proteolysis at muscle level. If