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Sample records for human absorptive enterocytes

  1. Permeabilization of enterocytes induced by absorption of dietary fat

    DEFF Research Database (Denmark)

    Danielsen, Erik Michael; Hansen, Gert H; Rasmussen, Karina

    2013-01-01

    penetrated the epithelium and accumulated in the basal lamina and the lamina propria. LY was also seen in the paracellular space, whereas villus enterocytes were generally only weakly labeled except for small amounts taken up by apical endocytosis. In the crypts, however, fat absorption induced cell...

  2. Intestinal absorption of vitamin D: from the meal to the enterocyte.

    Science.gov (United States)

    Reboul, Emmanuelle

    2015-02-01

    Vitamin D plays key roles in bone, infectious, inflammatory and metabolic diseases. As most people get inadequate sun exposure for sufficient vitamin D status, they need adequate intake of dietary vitamin D. Many studies see optimizing vitamin D status as a public health priority. It is thus vital to gain deeper insight into vitamin D intestinal absorption. It was long assumed that vitamin D intestinal absorption is a passive process, but new data from our laboratory showed that it is actually far more complex than previously thought. This review describes the fate of vitamin D in the human upper gastrointestinal lumen during digestion and focuses on the proteins involved in the intestinal membrane and cellular transport of vitamin D across the enterocyte. Although recent data significantly improve our understanding of vitamin D intestinal absorption, further studies are still needed to increase our knowledge of the molecular mechanisms underlying this phenomenon.

  3. Intestinal alkaline phosphatase: selective endocytosis from the enterocyte brush border during fat absorption

    DEFF Research Database (Denmark)

    Hansen, Gert Helge; Niels-Christiansen, Lise-Lotte; Immerdal, Lissi

    2007-01-01

    explants. By immunofluorescence microscopy, fat absorption caused a translocation of IAP from the enterocyte brush border to the interior of the cell, whereas other brush-border enzymes were unaffected. By electron microscopy, the translocation occurred by a rapid (5 min) induction of endocytosis via....... A lipid analysis revealed that fat absorption caused a marked increase in the microvillar membrane contents of free fatty acids. In conclusion, fat absorption rapidly induces a transient clathrin-dependent endocytosis via coated pits from the enterocyte brush border. The process selectively internalizes...

  4. Arginine does not exacerbate markers of inflammation in cocultures of human enterocytes and leukocytes

    DEFF Research Database (Denmark)

    Parlesak, Alexandr; Negrier, I.; Neveux, N.

    2007-01-01

    , a monolayer of intestinal epithelial cells (Caco-2) separated compartments with nonpathogenic Escherichia coli and mononuclear leukocytes. Activation of enterocytes and leukocytes was assessed by the measurement of nitric oxide, TNF-alpha, IL-6, IL-8, IL-10, and IFN-gamma. Further outcomes were...... with arginine did not affect epithelial integrity, production of any of the cytokines investigated, or the amount of nitric oxide. The amino acid used primarily by nonstimulated intestinal epithelial cells cocultured with leukocytes was glutamine. Activation of IEC with bacteria significantly enhanced......-talk between human enterocytes and leukocytes. Because it also does not seem to affect the integrity of enterocyte layers, a detrimental role of arginine during septic-like conditions seems unlikely....

  5. Scavenger receptor class B type I (SR-BI) in pig enterocytes: trafficking from the brush border to lipid droplets during fat absorption

    DEFF Research Database (Denmark)

    Hansen, Gert Helge; Niels-Christiansen, Lise-Lotte W; Immerdal, Lissi

    2003-01-01

    but its role in the small intestine remains unclear. AIM AND METHODS: To gain insight into the possible function of pig SR-BI during uptake of dietary fat, its localisation in enterocytes was studied in the fasting state and during fat absorption by immunogold electron microscopy and subcellular...... fat, SR-BI is endocytosed from the enterocyte brush border and accumulates in cytoplasmic lipid droplets. Internalisation of the receptor occurs mainly by clathrin coated pits rather than by a caveolae/lipid raft based mechanism....

  6. Rapid reversal of human intestinal ischemia-reperfusion induced damage by shedding of injured enterocytes and reepithelialisation.

    Directory of Open Access Journals (Sweden)

    Joep P M Derikx

    Full Text Available BACKGROUND: Intestinal ischemia-reperfusion (IR is a phenomenon related to physiological conditions (e.g. exercise, stress and to pathophysiological events (e.g. acute mesenteric ischemia, aortic surgery. Although intestinal IR has been studied extensively in animals, results remain inconclusive and data on human intestinal IR are scarce. Therefore, an experimental harmless model for human intestinal IR was developed, enabling us to clarify the sequelae of human intestinal IR for the first time. METHODS AND FINDINGS: In 30 patients undergoing pancreatico-duodenectomy we took advantage of the fact that in this procedure a variable length of jejunum is removed. Isolated jejunum (5 cm was subjected to 30 minutes ischemia followed by reperfusion. Intestinal Fatty Acid Binding Protein (I-FABP arteriovenous concentration differences across the bowel segment were measured before and after ischemia to assess epithelial cell damage. Tissue sections were collected after ischemia and at 25, 60 and 120 minutes reperfusion and stained with H&E, and for I-FABP and the apoptosis marker M30. Bonferroni's test was used to compare I-FABP differences. Mean (SEM arteriovenous concentration gradients of I-FABP across the jejunum revealed rapidly developing epithelial cell damage. I-FABP release significantly increased from 290 (46 pg/ml before ischemia towards 3,997 (554 pg/ml immediately after ischemia (p<0.001 and declined gradually to 1,143 (237 pg/ml within 1 hour reperfusion (p<0.001. Directly after ischemia the intestinal epithelial lining was microscopically normal, while subepithelial spaces appeared at the villus tip. However, after 25 minutes reperfusion, enterocyte M30 immunostaining was observed at the villus tip accompanied by shedding of mature enterocytes into the lumen and loss of I-FABP staining. Interestingly, within 60 minutes reperfusion the epithelial barrier resealed, while debris of apoptotic, shedded epithelial cells was observed in the lumen

  7. Strain-Dependent Induction of Human Enterocyte Apoptosis by Blastocystis Disrupts Epithelial Barrier and ZO-1 Organization in a Caspase 3- and 9-Dependent Manner

    Science.gov (United States)

    Teo, Joshua D. W.; Tan, Kevin S. W.

    2014-01-01

    Blastocystis is an emerging protistan parasite colonizing the human intestine. It is frequently reported to cause general intestinal symptoms of vomiting, diarrhea, and abdominal pain. We recently demonstrated that Blastocystis rearranged cytoskeletal proteins and induced intestinal epithelial barrier compromise. The effect of Blastocystis on enterocyte apoptosis is unknown, and a possible link between microbially induced enterocyte apoptosis and increased epithelial permeability has yet to be determined. The aim of this study is to assess if Blastocystis induces human enterocyte apoptosis and whether this effect influences human intestinal epithelial barrier function. Monolayers of polarized human colonic epithelial cell-line Caco-2 were incubated with Blastocystis subtype 7 and subtype 4. Assays for both early and late markers of apoptosis, phosphatidylserine externalization, and nuclear fragmentation, respectively, showed that Blastocystis ST-7, but not ST-4, significantly increased apoptosis in enterocytes, suggesting that Blastocystis exhibits host specificity and strain-to-strain variation in pathogenicity. ST-7 also activated Caco-2 caspases 3 and 9 but not 8. ST-7 induced changes in epithelial resistance, permeability, and tight junction (ZO-1) localization. Pretreatment of Caco-2 monolayers with a pan-caspase inhibitor z-VAD-fmk significantly inhibited these changes. This suggests a role for enterocyte apoptosis in Blastocystis-mediated epithelial barrier compromise in the human intestine. PMID:24822183

  8. Strain-Dependent Induction of Human Enterocyte Apoptosis by Blastocystis Disrupts Epithelial Barrier and ZO-1 Organization in a Caspase 3- and 9-Dependent Manner

    Directory of Open Access Journals (Sweden)

    Zhaona Wu

    2014-01-01

    Full Text Available Blastocystis is an emerging protistan parasite colonizing the human intestine. It is frequently reported to cause general intestinal symptoms of vomiting, diarrhea, and abdominal pain. We recently demonstrated that Blastocystis rearranged cytoskeletal proteins and induced intestinal epithelial barrier compromise. The effect of Blastocystis on enterocyte apoptosis is unknown, and a possible link between microbially induced enterocyte apoptosis and increased epithelial permeability has yet to be determined. The aim of this study is to assess if Blastocystis induces human enterocyte apoptosis and whether this effect influences human intestinal epithelial barrier function. Monolayers of polarized human colonic epithelial cell-line Caco-2 were incubated with Blastocystis subtype 7 and subtype 4. Assays for both early and late markers of apoptosis, phosphatidylserine externalization, and nuclear fragmentation, respectively, showed that Blastocystis ST-7, but not ST-4, significantly increased apoptosis in enterocytes, suggesting that Blastocystis exhibits host specificity and strain-to-strain variation in pathogenicity. ST-7 also activated Caco-2 caspases 3 and 9 but not 8. ST-7 induced changes in epithelial resistance, permeability, and tight junction (ZO-1 localization. Pretreatment of Caco-2 monolayers with a pan-caspase inhibitor z-VAD-fmk significantly inhibited these changes. This suggests a role for enterocyte apoptosis in Blastocystis-mediated epithelial barrier compromise in the human intestine.

  9. A lysine- and glutamic acid-rich protein, KERP1, from Entamoeba histolytica binds to human enterocytes.

    Science.gov (United States)

    Seigneur, Marie; Mounier, Joelle; Prevost, Marie-Christine; Guillén, Nancy

    2005-04-01

    Contact-dependent cytolysis of host cells by Entamoeba histolytica is an important hallmark of amoebiasis that points out the importance of molecules involved in the interaction between the parasite and the human cells. To decipher the molecular and cellular mechanisms supporting the invasion of the intestinal epithelium by E. histolytica, we analysed proteins involved in the interaction of the parasite with enterocytes. Affinity chromatography revealed several amoebic proteins interacting with purified brush border of differentiated Caco2 cells. Among them were found the intermediate subunit of the Gal/GalNAc lectin, an alpha-actinin-like protein and two new proteins KERP1 and KERP2 rich in lysine and glutamic acid. In silico analysis revealed the presence of KERP2 in the closely related non-pathogenic amoeba species Entamoeba dispar but not of KERP1. In additon, polymerase chain reaction analysis allowed to suggest the absence of kerp1 homologous gene in E. dispar. Therefore, we concentrated on the cellular analysis of KERP1. Cloning of the KERP1-encoding gene, production of a recombinant protein in Escherichia coli and production of a specific antibody allowed us to show the following properties: (i) purified KERP1 binds to epithelial cell surface, (ii) KERP1 is located on the plasma membrane and in vesicles of trophozoites and (iii) KERP1 is delivered in the interstitial area between the trophozoites and the intestinal cells.

  10. Enterocyte protection – a new goal in ICU nutrition

    African Journals Online (AJOL)

    2007-02-08

    Feb 8, 2007 ... Enterocytes are either secretory or absorptive. Secretory function is reduced in times of physiological stress such as critical illness but the basal metabolic activity of both types of cells still requires a supply of nutrients. Seventy per cent of the nutrition required by enterocytes is obtained from the gut lumen.

  11. Modeling of drug-mediated CYP3A4 induction by using human iPS cell-derived enterocyte-like cells

    Energy Technology Data Exchange (ETDEWEB)

    Negoro, Ryosuke [Laboratory of Biochemistry and Molecular Biology, Graduate School of Pharmaceutical Sciences, Osaka University, Osaka 565-0871 (Japan); Takayama, Kazuo [Laboratory of Biochemistry and Molecular Biology, Graduate School of Pharmaceutical Sciences, Osaka University, Osaka 565-0871 (Japan); The Keihanshin Consortium for Fostering the Next Generation of Global Leaders in Research (K-CONNEX), Kyoto University, Kyoto 606-8302 (Japan); Laboratory of Hepatocyte Regulation, National Institute of Biomedical Innovation, Health and Nutrition, Osaka 567-0085 (Japan); Nagamoto, Yasuhito [Laboratory of Biochemistry and Molecular Biology, Graduate School of Pharmaceutical Sciences, Osaka University, Osaka 565-0871 (Japan); Laboratory of Hepatocyte Regulation, National Institute of Biomedical Innovation, Health and Nutrition, Osaka 567-0085 (Japan); Sakurai, Fuminori [Laboratory of Biochemistry and Molecular Biology, Graduate School of Pharmaceutical Sciences, Osaka University, Osaka 565-0871 (Japan); Laboratory of Regulatory Sciences for Oligonucleotide Therapeutics, Clinical Drug Development Project, Graduate School of Pharmaceutical Sciences, Osaka University Osaka 565-0871 (Japan); Tachibana, Masashi [Laboratory of Biochemistry and Molecular Biology, Graduate School of Pharmaceutical Sciences, Osaka University, Osaka 565-0871 (Japan); Mizuguchi, Hiroyuki, E-mail: mizuguch@phs.osaka-u.ac.jp [Laboratory of Biochemistry and Molecular Biology, Graduate School of Pharmaceutical Sciences, Osaka University, Osaka 565-0871 (Japan); Laboratory of Hepatocyte Regulation, National Institute of Biomedical Innovation, Health and Nutrition, Osaka 567-0085 (Japan); Global Center for Medical Engineering and Informatics, Osaka University, Osaka 565-0871 (Japan)

    2016-04-15

    Many drugs have potential to induce the expression of drug-metabolizing enzymes, particularly cytochrome P450 3A4 (CYP3A4), in small intestinal enterocytes. Therefore, a model that can accurately evaluate drug-mediated CYP3A4 induction is urgently needed. In this study, we overlaid Matrigel on the human induced pluripotent stem cells-derived enterocyte-like cells (hiPS-ELCs) to generate the mature hiPS-ELCs that could be applied to drug-mediated CYP3A4 induction test. By overlaying Matrigel in the maturation process of enterocyte-like cells, the gene expression levels of intestinal markers (VILLIN, sucrase-isomaltase, intestine-specific homeobox, caudal type homeobox 2, and intestinal fatty acid-binding protein) were enhanced suggesting that the enterocyte-like cells were maturated by Matrigel overlay. The percentage of VILLIN-positive cells in the hiPS-ELCs found to be approximately 55.6%. To examine the CYP3A4 induction potential, the hiPS-ELCs were treated with various drugs. Treatment with dexamethasone, phenobarbital, rifampicin, or 1α,25-dihydroxyvitamin D3 resulted in 5.8-fold, 13.4-fold, 9.8-fold, or 95.0-fold induction of CYP3A4 expression relative to that in the untreated controls, respectively. These results suggest that our hiPS-ELCs would be a useful model for CYP3A4 induction test. - Highlights: • The hiPS-ELCs were matured by Matrigel overlay. • The hiPS-ELCs expressed intestinal nuclear receptors, such as PXR, GR and VDR. • The hiPS-ELC is a useful model for the drug-mediated CYP3A4 induction test.

  12. Apical secretion of apolipoproteins from enterocytes

    DEFF Research Database (Denmark)

    Danielsen, E M; Hansen, Gert Helge; Poulsen, Mona Dam

    1993-01-01

    that enterocytes release most of their newly made free apo A-1 and a significant portion of apo B-48 by exocytosis via the brush border membrane into the intestinal lumen. Fat absorption reduced apolipoprotein secretion to the medium and induced the formation of chylomicrons, containing apo A-1 at their surface...

  13. Shiga toxin 1 interaction with enterocytes causes apical protein mistargeting through the depletion of intracellular galectin-3

    Energy Technology Data Exchange (ETDEWEB)

    Laiko, Marina; Murtazina, Rakhilya; Malyukova, Irina [Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205 (United States); Zhu, Chengru; Boedeker, Edgar C. [Department of Medicine, University of New Mexico School of Medicine, Albuquerque, NM 87131 (United States); Gutsal, Oksana [Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205 (United States); O' Malley, Robert; Cole, Robert N. [Department of Biochemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205 (United States); Tarr, Phillip I. [Department of Pediatrics, Washington University School of Medicine, St. Louis, MO 63110 (United States); Murray, Karen F. [Department of Pediatrics, Children' s Hospital and Regional Medical Center, Seattle, WA 98105 (United States); Kane, Anne [The Tufts New England Medical Center, Boston, MA 02111 (United States); Donowitz, Mark [Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205 (United States); Kovbasnjuk, Olga, E-mail: okovbas1@jhmi.edu [Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205 (United States)

    2010-02-15

    Shiga toxins (Stx) 1 and 2 are responsible for intestinal and systemic sequelae of infection by enterohemorrhagic Escherichia coli (EHEC). However, the mechanisms through which enterocytes are damaged remain unclear. While secondary damage from ischemia and inflammation are postulated mechanisms for all intestinal effects, little evidence excludes roles for more primary toxin effects on intestinal epithelial cells. We now document direct pathologic effects of Stx on intestinal epithelial cells. We study a well-characterized rabbit model of EHEC infection, intestinal tissue and stool samples from EHEC-infected patients, and T84 intestinal epithelial cells treated with Stx1. Toxin uptake by intestinal epithelial cells in vitro and in vivo causes galectin-3 depletion from enterocytes by increasing the apical galectin-3 secretion. This Shiga toxin-mediated galectin-3 depletion impairs trafficking of several brush border structural proteins and transporters, including villin, dipeptidyl peptidase IV, and the sodium-proton exchanger 2, a major colonic sodium absorptive protein. The mistargeting of proteins responsible for the absorptive function might be a key event in Stx1-induced diarrhea. These observations provide new evidence that human enterocytes are directly damaged by Stx1. Conceivably, depletion of galectin-3 from enterocytes and subsequent apical protein mistargeting might even provide a means whereby other pathogens might alter intestinal epithelial absorption and produce diarrhea.

  14. The CpAL system regulates changes of the trans-epithelial resistance of human enterocytes during Clostridium perfringens type C infection.

    Science.gov (United States)

    Nava, Porfirio; Vidal, Jorge E

    2016-06-01

    Clostridium perfringens type C strains produce severe disease in humans and animals including enterotoxaemia and hemorrhagic diarrhea. Type C disease is mediated by production of toxins that damage the site of infection inducing loss of bloody fluids. Production of type C toxins, such as CPA, PFO, and, CPB is regulated by the C. perfringens Agr-like (CpAL) quorum sensing (QS) system. The CpAL system is also required to recapitulate, in vivo, intestinal signs of C. perfringens type C-induced disease, including hemorrhagic diarrhea and accumulation of fluids. The intestinal epithelium forms a physical barrier, made up of a series of intercellular junctions including tight junctions (TJs), adherens junctions (AJs) and desmosomes (DMs). This selective barrier regulates important physiological processes, including paracellular movement of ions and solutes, which, if altered, results in loss of fluids into the intestinal lumen. In this work, the effects of C. perfringens infection on the barrier function of intestinal epithelial cells was evaluated by measuring trans-epithelial resistance (TEER). Our studies demonstrate that infection of human enterocytes with C. perfringens type C strain CN3685 induced a significant drop on TEER. Changes in TEER were mediated by the CpAL system as a CN3685ΔagrB mutant did not induce such a drop. Physical contact between bacteria and enterocytes produced more pronounced changes in TEER and this phenomenon appeared also to be mediated by the CpAL system. Finally, immunofluorescence studies demonstrate that C. perfringens type C infection redistribute TJs protein occludin, and Claudin-3, and DMs protein desmoglein-2, but did not affect the AJs protein E-cadherin. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Sub-Emetic Toxicity of Bacillus cereus Toxin Cereulide on Cultured Human Enterocyte-Like Caco-2 Cells

    Directory of Open Access Journals (Sweden)

    Andreja Rajkovic

    2014-08-01

    Full Text Available Cereulide (CER intoxication occurs at relatively high doses of 8 µg/kg body weight. Recent research demonstrated a wide prevalence of low concentrations of CER in rice and pasta dishes. However, the impact of exposure to low doses of CER has not been studied before. In this research, we investigated the effect of low concentrations of CER on the behavior of intestinal cells using the Caco-2 cell line. The MTT (mitochondrial 3-(4,5-dimethylthiazol-2-yl-2,5-diphenyltetrazolium bromide and the SRB (sulforhodamine B reactions were used to measure the mitochondrial activity and cellular protein content, respectively. Both assays showed that differentiated Caco-2 cells were sensitive to low concentrations of CER (in a MTT reaction of 1 ng/mL after three days of treatment; in an SRB reaction of 0.125 ng/mL after three days of treatment. Cell counts revealed that cells were released from the differentiated monolayer at 0.5 ng/mL of CER. Additionally, 0.5 and 2 ng/mL of CER increased the lactate presence in the cell culture medium. Proteomic data showed that CER at a concentration of 1 ng/mL led to a significant decrease in energy managing and H2O2 detoxification proteins and to an increase in cell death markers. This is amongst the first reports to describe the influence of sub-emetic concentrations of CER on a differentiated intestinal monolayer model showing that low doses may induce an altered enterocyte metabolism and membrane integrity.

  16. Effect of soy and milk protein-related compounds on Listeria monocytogenes infection in human enterocyte Caco-2 cells and A/J mice.

    Science.gov (United States)

    Kuda, Takashi; Nakamura, Shinsuke; An, Choa; Takahashi, Hajime; Kimura, Bon

    2012-10-15

    Listeria monocytogenes causes listeriosis in humans, mainly through the consumption of ready-to-eat foods such as cheese. Immunocompromised persons, the elderly, and pregnant women and their fetuses or newborns are at the highest risk for the infection. We examined the effects of dietary milk-casein (MC) and soy-protein (SP), and their digested compounds tryptone (TP) and phytone peptone (PP), respectively, on L. monocytogenes invasion and infection in human enterocyte-like Caco-2 cells and A/J mice. Invasion into Caco-2 cells tended to be high with TP. In A/J mice orally infected with L. monocytogenes, viable numbers in the liver and spleen showed a tendency of decreasing with the 20% SP diet compared to the 20% MC diet. SP suppressed the inflammation marker tumour necrosis factor-α in spleen tissue. Furthermore, bacteria lipopolysaccharide (LPS)-stimulated nitric oxide (NO) secretion from murine macrophage RAW 264.7 cells was suppressed by PP more than TP. These results suggest that major dietary proteins might affect infection and inflammation by L. monocytogenes. Copyright © 2012 Elsevier Ltd. All rights reserved.

  17. Enterocyte-Associated Microbiome of the Hadza Hunter-Gatherers.

    Science.gov (United States)

    Turroni, Silvia; Rampelli, Simone; Centanni, Manuela; Schnorr, Stephanie L; Consolandi, Clarissa; Severgnini, Marco; Peano, Clelia; Soverini, Matteo; Falconi, Mirella; Crittenden, Alyssa N; Henry, Amanda G; Brigidi, Patrizia; Candela, Marco

    2016-01-01

    By means of a recently developed non-invasive ex vivo minimal model based on the interaction of the human enterocyte-like HT29 cell line and fecal slurries, we explored the enterocyte-associated microbiome of 21 Hadza hunter-gatherers and nine urban living Italians. Though reductionist, this model allows inferring the microbiota structural and functional arrangement as it interacts with enterocytes. Microbial suspensions obtained from Hadza or Italian stools were first evaluated for structural integrity by high resolution-scanning electron microscopy and co-incubated with HT29 cell monolayers. The enterocyte adherent microbiota fraction was then characterized by 16S rRNA gene sequencing and predictive functional profiling using PICRUSt. Compared to Italians, the Hadza enterocyte-associated microbiome was characterized by a greater amount of adhesive microorganisms with pathogenic potential, such as Proteobacteria, Erysipelotrichaceae, Enterococcus, Clostridium and Sarcina. These compositional characteristics were reflected in a functional enrichment in membrane transport, signal transduction, signaling molecules and interaction. Our results depict a new interesting mutualistic configuration of the enterocyte-associated microbiome in Hadza, stressing the importance of microbe-host interaction at the mucosal surface along the course of human evolution.

  18. The symbiotic bacterial surface factor polysaccharide A on Bacteroides fragilis inhibits IL-1β-induced inflammation in human fetal enterocytes via toll receptors 2 and 4.

    Directory of Open Access Journals (Sweden)

    Fei Jiang

    Full Text Available Colonizing bacteria interacting with the immature, unlike the mature, human intestine favors inflammation over immune homeostasis. As a result, ten percent of premature infants under 1500 grams weight develop an inflammatory necrosis of the intestine after birth, e.g., necrotizing enterocolitis (NEC. NEC is a major health problem in this population causing extensive morbidity and mortality and an enormous expenditure of health care dollars. NEC can be prevented by giving preterm infants their mother's expressed breast milk or ingesting selective probiotic organisms. Vaginally delivered, breast fed newborns develop health promoting bacteria ("pioneer" bacteria which preferentially stimulate intestinal host defense and anti-inflammation. One such "pioneer" organism is Bacteroides fragilis with a polysaccharide (PSA on its capsule. B. fragilis has been shown developmentally in intestinal lymphocytes and dendritic cells to produce a balanced T-helper cell (TH1/TH2 response and to reduce intestinal inflammation by activity through the TLR2 receptor stimulating IL-10 which inhibits IL-17 causing inflammation. No studies have been done on the role of B. fragilis PSA on fetal enterocytes and its increased inflammation. Accordingly, using human and mouse fetal intestinal models, we have shown that B. fragilis with PSA and PSA alone inhibits IL-1β-induced IL-8 inflammation in fetal and NEC intestine. We have also begun to define the mechanism for this unique inflammation noted in fetal intestine. We have shown that B. fragilis PSA anti-inflammation requires both the TLR2 and TLR4 receptor and is in part mediated by the AP1 transcription factor (TLR2 which is developmentally regulated. These observations may help to devise future preventative treatments of premature infants against NEC.

  19. Dermal absorption of chlorpyrifos in human volunteers

    NARCIS (Netherlands)

    Meuling, W.J.; Ravensberg, L.C.; Roza, L.; Hemmen, J.J. van

    2005-01-01

    Objective: The methods and results are described of a study on the dermal absorption of chlorpyrifos (CPF) in humans established via urinary excretion of the metabolite 3,5,6-trichloro-2-pyridinol (TCP). Methods: Two dermal, single, doses of CPF were applied in two study groups (A and B) each

  20. Acute Effects of Sugars and Artificial Sweeteners on Small Intestinal Sugar Transport: A Study Using CaCo-2 Cells As an In Vitro Model of the Human Enterocyte.

    Science.gov (United States)

    O'Brien, Patrick; Corpe, Christopher Peter

    2016-01-01

    The gastrointestinal tract is responsible for the assimilation of nutrients and plays a key role in the regulation of nutrient metabolism and energy balance. The molecular mechanisms by which intestinal sugar transport are regulated are controversial. Based on rodent studies, two models currently exist that involve activation of the sweet-taste receptor, T1R2/3: an indirect model, whereby luminal carbohydrates activate T1R2/3 expressed on enteroendocrine cells, resulting in the release of gut peptides which in turn regulate enterocyte sugar transport capacity; and a direct model, whereby T1R2/3 expressed on the enterocyte regulates enterocyte function. To study the direct model of intestinal sugar transport using CaCo-2 cells, a well-established in vitro model of the human enterocyte. Uptake of 10mM 14C D-Glucose and D-Fructose into confluent CaCo-2/TC7 cells was assessed following 3hr preincubation with sugars and artificial sweeteners in the presence and absence of the sweet taste receptor inhibitor, lactisole. Expression of the intestinal sugar transporters and sweet-taste receptors were also determined by RT-PCR. In response to short term changes in extracellular glucose and glucose/fructose concentrations (2.5mM to 75mM) carrier-mediated sugar uptake mediated by SGLT1 and/or the facilitative hexose transporters (GLUT1,2,3 and 5) was increased. Lactisole and artificial sweeteners had no effect on sugar transport regulated by glucose alone; however, lactisole increased glucose transport in cells exposed to glucose/fructose. RT-PCR revealed Tas1r3 and SGLT3 gene expression in CaCo-2/TC7 cells, but not Tas1r2. In the short term, enterocyte sugar transport activities respond directly to extracellular glucose levels, but not fructose or artificial sweeteners. We found no evidence of a functional heterodimeric sweet taste receptor, T1R2/3 in CaCo-2 cells. However, when glucose/fructose is administered together there is an inhibitory effect on glucose transport

  1. Acute Effects of Sugars and Artificial Sweeteners on Small Intestinal Sugar Transport: A Study Using CaCo-2 Cells As an In Vitro Model of the Human Enterocyte.

    Directory of Open Access Journals (Sweden)

    Patrick O'Brien

    Full Text Available The gastrointestinal tract is responsible for the assimilation of nutrients and plays a key role in the regulation of nutrient metabolism and energy balance. The molecular mechanisms by which intestinal sugar transport are regulated are controversial. Based on rodent studies, two models currently exist that involve activation of the sweet-taste receptor, T1R2/3: an indirect model, whereby luminal carbohydrates activate T1R2/3 expressed on enteroendocrine cells, resulting in the release of gut peptides which in turn regulate enterocyte sugar transport capacity; and a direct model, whereby T1R2/3 expressed on the enterocyte regulates enterocyte function.To study the direct model of intestinal sugar transport using CaCo-2 cells, a well-established in vitro model of the human enterocyte.Uptake of 10mM 14C D-Glucose and D-Fructose into confluent CaCo-2/TC7 cells was assessed following 3hr preincubation with sugars and artificial sweeteners in the presence and absence of the sweet taste receptor inhibitor, lactisole. Expression of the intestinal sugar transporters and sweet-taste receptors were also determined by RT-PCR.In response to short term changes in extracellular glucose and glucose/fructose concentrations (2.5mM to 75mM carrier-mediated sugar uptake mediated by SGLT1 and/or the facilitative hexose transporters (GLUT1,2,3 and 5 was increased. Lactisole and artificial sweeteners had no effect on sugar transport regulated by glucose alone; however, lactisole increased glucose transport in cells exposed to glucose/fructose. RT-PCR revealed Tas1r3 and SGLT3 gene expression in CaCo-2/TC7 cells, but not Tas1r2.In the short term, enterocyte sugar transport activities respond directly to extracellular glucose levels, but not fructose or artificial sweeteners. We found no evidence of a functional heterodimeric sweet taste receptor, T1R2/3 in CaCo-2 cells. However, when glucose/fructose is administered together there is an inhibitory effect on glucose

  2. Synergistic effects of high fat feeding and apolipoprotein E deletion on enterocytic amyloid-beta abundance

    Directory of Open Access Journals (Sweden)

    Dhaliwal Satvinder S

    2008-04-01

    Full Text Available Abstract Background Amyloid-β (Aβ, a key protein found in amyloid plaques of subjects with Alzheimer's disease is expressed in the absorptive epithelial cells of the small intestine. Ingestion of saturated fat significantly enhances enterocytic Aβ abundance whereas fasting abolishes expression. Apolipoprotein (apo E has been shown to directly modulate Aβ biogenesis in liver and neuronal cells but it's effect in enterocytes is not known. In addition, apo E modulates villi length, which may indirectly modulate Aβ as a consequence of differences in lipid absorption. This study compared Aβ abundance and villi length in wild-type (WT and apo E knockout (KO mice maintained on either a low-fat or high-fat diet. Wild-type C57BL/6J and apo E KO mice were randomised for six-months to a diet containing either 4% (w/w unsaturated fats, or chow comprising 16% saturated fats and 1% cholesterol. Quantitative immunohistochemistry was used to assess Aβ abundance in small intestinal enterocytes. Apo E KO mice given the low-fat diet had similar enterocytic Aβ abundance compared to WT controls. Results The saturated fat diet substantially increased enterocytic Aβ in WT and in apo E KO mice, however the effect was greater in the latter. Villi height was significantly greater in apo E KO mice than for WT controls when given the low-fat diet. However, WT mice had comparable villi length to apo E KO when fed the saturated fat and cholesterol enriched diet. There was no effect of the high-fat diet on villi length in apo E KO mice. Conclusion The findings of this study are consistent with the notion that lipid substrate availability modulates enterocytic Aβ. Apo E may influence enterocytic lipid availability by modulating absorptive capacity.

  3. Dietary protein absorption of the small intestine in human neonates

    NARCIS (Netherlands)

    Schaart, Maaike W.; de Bruijn, Adrianus C. J. M.; Tibboel, Dick; Renes, Ingrid B.; van Goudoever, Johannes B.

    2007-01-01

    The intestine plays a key role in the absorption of dietary proteins, which determines growth of human neonates. Bowel resection in the neonatal period brings loss of absorptive and protective surface and may consequently lead to malabsorption of dietary nutrients. However, there are no data on net

  4. Plasma citrulline is a biomarker of enterocyte mass and an indicator of parenteral nutrition in HIV-infected patients

    National Research Council Canada - National Science Library

    Crenn, Pascal; De Truchis, Pierre; Neveux, Nathalie; Galpérine, Tatiana; Cynober, Luc; Melchior, Jean Claude

    2009-01-01

    Plasma citrulline is a biomarker of enterocyte mass and function in humans. We evaluated citrulline in the reemerging context of diarrhea in HIV-infected patients receiving highly active antiretroviral therapy...

  5. Infrared absorption of human breast tissues in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Liu Chenglin [Department of Physics, Surface Physics Laboratory (National Key laboratory), Synchrotron Radiation Research Center, Fudan University, Shanghai 200433 (China); Physics Department of Yancheng Teachers' College, Yancheng 224002 (China); Zhang Yuan [Department of Physics, Surface Physics Laboratory (National Key laboratory), Synchrotron Radiation Research Center, Fudan University, Shanghai 200433 (China); Yan Xiaohui [Department of Physics, Surface Physics Laboratory (National Key laboratory), Synchrotron Radiation Research Center, Fudan University, Shanghai 200433 (China); Zhang Xinyi [Department of Physics, Surface Physics Laboratory (National Key laboratory), Synchrotron Radiation Research Center, Fudan University, Shanghai 200433 (China) and Shanghai Research Center of Acupuncture and Meridian, Pudong, Shanghai 201203 (China)]. E-mail: xy-zhang@fudan.edu.cn; Li Chengxiang [National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029 (China); Yang Wentao [Cancer Hospital, Medical Center, Fudan University, Shanghai 200032 (China); Shi Daren [Cancer Hospital, Medical Center, Fudan University, Shanghai 200032 (China)

    2006-07-15

    The spectral characteristics of human breast tissues in normal status and during different cancerous stages have been investigated by synchrotron radiation based Fourier transform infrared (SR-FTIR) absorption spectroscopy. Thanks to the excellent synchrotron radiation infrared (IR) source, higher resolving power is achieved in SR-FTIR absorption spectra than in conventional IR absorption measurements. Obvious variations in IR absorption spectrum of breast tissues were found as they change from healthy to diseased, or say in progression to cancer. On the other hand, some specific absorption peaks were found in breast cancer tissues by SR-FTIR spectroscopic methods. These spectral characteristics of breast tissue may help us in early diagnosis of breast cancer.

  6. Vehicle effects on human stratum corneum absorption and skin penetration.

    Science.gov (United States)

    Zhang, Alissa; Jung, Eui-Chang; Zhu, Hanjiang; Zou, Ying; Hui, Xiaoying; Maibach, Howard

    2017-05-01

    This study evaluated the effects of three vehicles-ethanol (EtOH), isopropyl alcohol (IPA), and isopropyl myristate (IPM)-on stratum corneum (SC) absorption and diffusion of the [(14)C]-model compounds benzoic acid and butenafine hydrochloride to better understand the transport pathways of chemicals passing through and resident in SC. Following application of topical formulations to human dermatomed skin for 30 min, penetration flux was observed for 24 h post dosing, using an in vitro flow-through skin diffusion system. Skin absorption and penetration was compared to the chemical-SC (intact, delipidized, or SC lipid film) binding levels. A significant vehicle effect was observed for chemical skin penetration and SC absorption. IPA resulted in the greatest levels of intact SC/SC lipid absorption, skin penetration, and total skin absorption/penetration of benzoic acid, followed by IPM and EtOH, respectively. For intact SC absorption and total skin absorption/penetration of butenafine, the vehicle that demonstrated the highest level of sorption/penetration was EtOH, followed by IPA and IPM, respectively. The percent doses of butenafine that were absorbed in SC lipid film and penetrated through skin in 24 h were greatest for IPA, followed by EtOH and IPM, respectively. The vehicle effect was consistent between intact SC absorption and total chemical skin absorption and penetration, as well as SC lipid absorption and chemical penetration through skin, suggesting intercellular transport as a main pathway of skin penetration for model chemicals. These results suggest the potential to predict vehicle effects on skin permeability with simple SC absorption assays. As decontamination was applied 30 min after chemical exposure, significant vehicle effects on chemical SC partitioning and percutaneous penetration also suggest that skin decontamination efficiency is vehicle dependent, and an effective decontamination method should act on chemical solutes in the lipid domain.

  7. Meat protein fractions enhance nonheme iron absorption in humans.

    Science.gov (United States)

    Hurrell, Richard F; Reddy, Manju B; Juillerat, Marcel; Cook, James D

    2006-11-01

    The nature of the enhancing effect of muscle tissue on nonheme iron absorption in humans is unclear but thought to be related to muscle proteins. We conducted radioiron absorption studies to compare iron absorption from proteins isolated from beef and chicken muscle with that from freeze-dried beef and chicken muscle and from egg albumin. All meals contained an equivalent amount of protein as part of a semisynthetic liquid formula. Freeze-dried beef and chicken muscle increased iron absorption 180% (P egg albumin. When added to the meal at an equivalent protein level (15 g), the isolated beef protein and the isolated heme-free beef protein with 94 and 98% protein content, respectively, increased iron absorption to the same extent as the native beef muscle. Similarly, when added to the meal at an equivalent protein level (30 g), isolated chicken muscle protein (94% protein) increased iron absorption similarly to native chicken muscle. Iron absorption from the meal containing the isolated heme-free chicken protein, however, was 120% (P extraction and separation procedures. Our results support the hypothesis that the enhancing effect of muscle tissue on iron absorption is mainly protein related but indicate that other factors may also play a role.

  8. Scavenger receptor class B type I (SR-BI) is involved in vitamin E transport across the enterocyte

    Science.gov (United States)

    Reboul, Emmanuelle; Klein, Alexis; Bietrix, Florence; Gleize, Béatrice; Malezet-Desmoulins, Christiane; Schneider, Martina; Margotat, Alain; Lagrost, Laurent; Collet, Xavier; Borel, Patrick

    2006-01-01

    Although cellular uptake of vitamin E was initially described as a passive process, recent studies in the liver and brain have shown that SR-BI is involved in this phenomenon. As SR-BI is expressed at high levels in the intestine, the present study addressed the involvement of SR-BI in vitamin E trafficking across enterocytes. Apical uptake and efflux of the main dietary forms of vitamin E was examined using Caco-2 TC-7 cell monolayers as a model of human intestinal epithelium. RRR-γ-tocopherol bioavailability was compared between wild-type mice and mice overexpressing SR-BI in the intestine. The effect of vitamin E on enterocyte SR-BI mRNA levels was measured by real-time quantitative RT-PCR. Concentration-dependent curves for vitamin E uptake were similar for RRR-α-, RRR-γ- and DL-α-tocopherol. RRR-α-tocopherol transport was dependent on incubation temperature, with a 60% reduction in absorption at 4°C compared to 37°C (p<0.05). Vitamin E flux in enterocytes was directed from the apical to the basal side, with a relative 10-fold reduction in the transfer process when measured in the opposite direction (p<0.05). Co-incubation with cholesterol, γ-tocopherol or lutein significantly impaired α-tocopherol absorption. Anti-human SR-BI antibodies and BLT1 (a chemical inhibitor of lipid transport via SR-BI) blocked up to 80% of vitamin E uptake and up to 30 % of apical vitamin E efflux (p<0.05), and similar results were obtained for RRR-γ-tocopherol. SR-BI mRNA levels were not significantly modified after a 24-hour incubation of Caco-2 cells with vitamin E. Finally, RRR-γ-tocopherol bioavailability was 2.7-fold higher in mice overexpressing SR-BI than in wild-type mice (p<0.05). The present data show for the first time that vitamin E intestinal absorption is, at least partly, mediated by SR-BI. PMID:16380385

  9. Absorption and metabolic fate of bioactive dietary benzoxazinoids in humans

    DEFF Research Database (Denmark)

    Adhikari, Khem B; Laursen, Bente B; Gregersen, Per L

    2013-01-01

    glycosides, the reduction of hydroxamic acid glycosides, glucuronidation, and sulfation were the main mechanisms of the absorption and metabolism of benzoxazinoids. Conclusion These results indicate that following ingestion in healthy humans, a range of unmetabolized bioactive dietary benzoxazinoids...... of bioactive benzoxazinoids in humans. Methods and results The absorption, metabolism, and excretion of ten different dietary benzoxazinoids were examined by LC-MS/MS by analyzing plasma and urine from 20 healthy human volunteers after daily intake of 143 μmol of total benzoxazinoids from rye bread and rye...... benzoxazinoids with abundant HBOA-Glc (219 nmol × μmol−1 of creatinine). The sulfate and glucuronide conjugates of 2-hydroxy-1,4-benzoxazin-3-one (HBOA) and 2,4-dihydroxy-1,4-benzoxazin-3-one (DIBOA) were detected in plasma and urine, indicating substantial phase II metabolism. Direct absorption of lactam...

  10. Hydrothermal treatment and malting of barley improved zinc absorption but not calcium absorption in humans.

    Science.gov (United States)

    Fredlund, K; Bergman, E-L; Rossander-Hulthén, L; Isaksson, M; Almgren, A; Sandberg, A-S

    2003-12-01

    To study whether hydrothermal treatment or malting of barley (cv. Blenheim) improves zinc and calcium absorption in humans. : Two groups of 10 and 12 healthy subjects, respectively, were in a period of 2 months in a fasting state, served two single meals each containing porridge or breakfast cereals prepared from processed or unprocessed (control) barley (60 g). The meals included 200 g of milk, extrinsically labelled with (65)Zn and (47)Ca. Whole-body retention of both minerals was measured. The study was carried out at the Department of Radiation Physics, Sahlgrenska University Hospital, Göteborg. The subjects were recruited among students at the Göteborg University. None dropped out. The activities of (65)Zn and (47)Ca were measured by whole-body counting four to five times over a 4-week period after each meal. Zinc absorption from hydrothermally treated barley porridge, containing 28 mg P as inositol tri- to hexaphosphates (InsP(3)-InsP(6)), was significantly higher (P0.05), 21.1+/-6.8 vs 19.5+/-4.7% (n=12). Zinc absorption from breakfast cereals of malted barley with phytase activity and containing 70 mg P as InsP(3)-InsP(6,) was significantly higher (P0.05). Improvements of zinc absorption in breakfast meals can be achieved by optimised hydrothermal treatment or malting of barley. Calcium absorption was not influenced in the meals in this study. Supported by Semper AB, Sweden, Oy Lahden Polttimo, Finland, the SL-Foundation, Sweden, Swedish National Board for Industrial and Technical Development (NUTEK), the Nordic Industrial Foundation, Swedish Council for Forestry and Agricultural Research (SJFR, project no 50.0306/97).

  11. Intestinal Cgi-58 deficiency reduces postprandial lipid absorption.

    Directory of Open Access Journals (Sweden)

    Ping Xie

    Full Text Available Comparative Gene Identification-58 (CGI-58, a lipid droplet (LD-associated protein, promotes intracellular triglyceride (TG hydrolysis in vitro. Mutations in human CGI-58 cause TG accumulation in numerous tissues including intestine. Enterocytes are thought not to store TG-rich LDs, but a fatty meal does induce temporary cytosolic accumulation of LDs. Accumulated LDs are eventually cleared out, implying existence of TG hydrolytic machinery in enterocytes. However, identities of proteins responsible for LD-TG hydrolysis remain unknown. Here we report that intestine-specific inactivation of CGI-58 in mice significantly reduces postprandial plasma TG concentrations and intestinal TG hydrolase activity, which is associated with a 4-fold increase in intestinal TG content and large cytosolic LD accumulation in absorptive enterocytes during the fasting state. Intestine-specific CGI-58 knockout mice also display mild yet significant decreases in intestinal fatty acid absorption and oxidation. Surprisingly, inactivation of CGI-58 in intestine significantly raises plasma and intestinal cholesterol, and reduces hepatic cholesterol, without altering intestinal cholesterol absorption and fecal neutral sterol excretion. In conclusion, intestinal CGI-58 is required for efficient postprandial lipoprotein-TG secretion and for maintaining hepatic and plasma lipid homeostasis. Our animal model will serve as a valuable tool to further define how intestinal fat metabolism influences the pathogenesis of metabolic disorders, such as obesity and type 2 diabetes.

  12. Absorption and metabolism of yerba mate phenolic compounds in humans.

    Science.gov (United States)

    Gómez-Juaristi, Miren; Martínez-López, Sara; Sarria, Beatriz; Bravo, Laura; Mateos, Raquel

    2018-02-01

    Bioavailability of yerba mate phenolic compounds was assessed in healthy humans. More than 34 metabolites were identified in biological fluids, mainly sulfated conjugates of caffeic and ferulic/isoferulic acids, in addition to non-metabolized caffeoyl-, feruloyl- and p-coumaroilquinic acids, with rapid appearance and clearance in plasma indicative of small intestinal absorption. These compounds amounted to 13.1% of the urinary metabolites. Delayed absorption of dihydrocaffeic, dihydroferulic and dihydrocoumaric acids and their phase II metabolites, in addition to feruloylglycine, pointed to their microbial origin and colonic absorption, accounting for 81.0% of excreted metabolites. Phase II flavonol metabolites (0.2%) derived mainly from rutin after colonic transformation and absorption were also detected. Additionally, dihydroferuloyl-, dihydrocaffeoyl- and dihydrocoumaroylquinic acids (5.7%) were identified, showing the most delayed kinetics. Total phenolic excretion (147.6μmol) corresponded to 13.2% of ingested phenols. In conclusion, yerba mate polyphenols are partially bioavailable and extensively metabolized, mainly by the colonic microbiota. Copyright © 2017. Published by Elsevier Ltd.

  13. Enterocyte protection - a new goal in ICU nutrition | Hodgson ...

    African Journals Online (AJOL)

    Enterocytes are among the most metabolically active cells in the body but are the least well supplied with blood even under resting conditions. Maintaining function of enterocytes has benefits that are becoming apparent in terms of improved outcomes from such diverse diseases as colorectal cancer and pneumonia.

  14. Investigation of the Assembly of Chylomicrons in Hamster Enterocytes Using Pluronic-L81 Acid as a Probe

    Directory of Open Access Journals (Sweden)

    Mahnaz Mardani

    2011-06-01

    Full Text Available A major function of the enterocytes is absorption, processing, and export of dietary lipids into the lymphatic system. Pluronic L-81 is a non-ionic hydrophobic surfactant, which specifically inhibits lipid absorption in the intestine when administered in vivo. This compound is therefore an attractive probe to perturb and investigate the molecular and intracellular events in chylomicron assembly in the enterocytes. In the present study pluronic acid was administered to hamsters followed by isolation of the enterocytes and cell fractionation to investigate the effect of pluronic acid on intracellular events in lipid absorption. Four types of diet were administered to hamsters for three weeks; low-fat chow, high-fat chow and each diet with or without added pluronic acid. Sub-cellular fractions of freshly isolated enterocytes were prepared. Consistent with morphological observation, the high fat diet resulted in a three-fold increase in the triacylglycerol (TAG content of the enterocytes and addition of pluronic acid to either the low fat or the high fat diets resulted in a ten-fold increase in cellular TAG levels. Determination of the mass of TAG and the time course of incorporation of 3H-triolein, administered by gavage, showed that the increased TAG was recovered in the microsomal (endoplasmic reticulum fraction and the cytosol. In microsomes, increased TAG was recovered mainly in the membrane although there was a significant amount in the microsomal luminal contents. Pluronic acid therefore acts at the level of the endoplasmic reticulum and inhibits the assembly of apo-B48 with chylomicron TAG. The excess TAG is transferred to cytosolic stores.

  15. Investigation of the assembly of chylomicrons in hamster enterocytes using pluronic-L81 acid as a probe.

    Science.gov (United States)

    Mardani, Mahnaz; Rezapour, Sadegh; Higgins, Joan A

    2011-01-01

    A major function of the enterocytes is absorption, processing, and export of dietary lipids into the lymphatic system. Pluronic L-81 is a non-ionic hydrophobic surfactant, which specifically inhibits lipid absorption in the intestine when administered in vivo. This compound is therefore an attractive probe to perturb and investigate the molecular and intracellular events in chylomicron assembly in the enterocytes. In the present study pluronic acid was administered to hamsters followed by isolation of the enterocytes and cell fractionation to investigate the effect of pluronic acid on intracellular events in lipid absorption. Four types of diet were administered to hamsters for three weeks; low-fat chow, high-fat chow and each diet with or without added pluronic acid. Sub-cellular fractions of freshly isolated enterocytes were prepared. Consistent with morphological observation, the high fat diet resulted in a three-fold increase in the triacylglycerol (TAG) content of the enterocytes and addition of pluronic acid to either the low fat or the high fat diets resulted in a ten-fold increase in cellular TAG levels. Determination of the mass of TAG and the time course of incorporation of 3H-triolein, administered by gavage, showed that the increased TAG was recovered in the microsomal (endoplasmic reticulum) fraction and the cytosol. In microsomes, increased TAG was recovered mainly in the membrane although there was a significant amount in the microsomal luminal contents. Pluronic acid therefore acts at the level of the endoplasmic reticulum and inhibits the assembly of apo-B48 with chylomicron TAG. The excess TAG is transferred to cytosolic stores.

  16. Regulatory Effects of Cu, Zn, and Ca on Fe Absorption: The Intricate Play between Nutrient Transporters

    Directory of Open Access Journals (Sweden)

    Nathalie Scheers

    2013-03-01

    Full Text Available Iron is an essential nutrient for almost every living organism because it is required in a number of biological processes that serve to maintain life. In humans, recycling of senescent erythrocytes provides most of the daily requirement of iron. In addition, we need to absorb another 1–2 mg Fe from the diet each day to compensate for losses due to epithelial sloughing, perspiration, and bleeding. Iron absorption in the intestine is mainly regulated on the enterocyte level by effectors in the diet and systemic regulators accessing the enterocyte through the basal lamina. Recently, a complex meshwork of interactions between several trace metals and regulatory proteins was revealed. This review focuses on advances in our understanding of Cu, Zn, and Ca in the regulation of iron absorption. Ascorbate as an important player is also considered.

  17. Absorption and excretion of cranberry-derived phenolics in humans.

    Science.gov (United States)

    Wang, Chengjun; Zuo, Yuegang; Vinson, Joe A; Deng, Yiwei

    2012-06-01

    Absorption and excretion of twenty cranberry-derived phenolics were studied following the consumption of cranberry juice, sauces, and fruits by healthy human volunteers. Plasma and urine samples were collected and analysed by gas chromatography-mass spectrometry (GC-MS). A high performance liquid chromatography (HPLC) method was employed for analysing urinary creatinine, which was used as a normalisation agent. Significant increases in the sum of plasma phenolics were observed with different concentration peaks (between 0.5 and 2h) for individual subjects. Some of the phenolics, such as trans-cinnamic, vanillic, p-coumaric acids, and catechin showed second plasma concentration peaks. All of cranberry-derived phenolics increased significantly in urine samples after the intake of each cranberry product. The high molecular weight quercetin and myricetin, which were abundant in cranberry foodstuffs, were not found in either plasma or urine samples. This study provided the fundamental information for understanding the absorption and excretion of phenolics in the human gastrointestinal system after dietary intake of cranberry products. Copyright © 2011 Elsevier Ltd. All rights reserved.

  18. Phase measurement of light absorption and scatter in human tissue

    Science.gov (United States)

    Chance, B.; Cope, M.; Gratton, E.; Ramanujam, N.; Tromberg, B.

    1998-10-01

    Analog and digital technologies are presented for precise measurement of propagation delay of photons from source and detector placed on portions of the human body. The goal of the apparatus design is to quantify absorption (μa) and scattering (μs') induced by biological pigments and biological structures, respectively. Body tissues are highly scattering with a mean distance between scatterers of less than a mm (at 700-850 nm). Significant absorption is mainly due to 5%-10% of the tissue volume occupied by blood. Measurement of μa and μs' is done by both time and frequency domain equipment. This article focuses upon frequency domain equipment because of its simplicity, reduced noise bandwidth, versatility, and the strong analogy to very high frequency/ultrahigh frequency communication devices, particularly those using phase modulation. Comparisons are made of homodyne and heterodyne systems together with evaluation of single and multiple side band systems, with particular emphasis on methods for multiplexed optical and radio frequencies by frequency encoding or time-sharing technologies. The applications of these phase modulation systems to quantitative brain and muscle blood oximetry, functional activity of the forebrain, and other important problems of medical science, are presented.

  19. Hypocholesterolaemic Activity of Lupin Peptides: Investigation on the Crosstalk between Human Enterocytes and Hepatocytes Using a Co-Culture System Including Caco-2 and HepG2 Cells.

    Science.gov (United States)

    Lammi, Carmen; Zanoni, Chiara; Ferruzza, Simonetta; Ranaldi, Giulia; Sambuy, Yula; Arnoldi, Anna

    2016-07-22

    Literature indicates that peptic and tryptic peptides derived from the enzymatic hydrolysis of lupin protein are able to modulate cholesterol metabolism in human hepatic HepG2 cells and that part of these peptides are absorbed in a small intestine model based on differentiated human Caco-2 cells. In this paper, a co-culture system, including Caco-2 and HepG2 cells, was investigated with two objectives: (a) to verify whether cholesterol metabolism in HepG2 cells was modified by the peptides absorption through Caco-2 cells; (b) to investigate how lupin peptides influence cholesterol metabolism in Caco-2 cells. The experiments showed that the absorbed peptides, not only maintained their bioactivity on HepG2 cells, but that this activity was improved by the crosstalk of the two cells systems in co-culture. In addition, lupin peptides showed a positive influence on cholesterol metabolism in Caco-2 cells, decreasing the proprotein convertase subtilisin/kexin type 9 (PCSK9) secretion.

  20. Hypocholesterolaemic Activity of Lupin Peptides: Investigation on the Crosstalk between Human Enterocytes and Hepatocytes Using a Co-Culture System Including Caco-2 and HepG2 Cells

    Directory of Open Access Journals (Sweden)

    Carmen Lammi

    2016-07-01

    Full Text Available Literature indicates that peptic and tryptic peptides derived from the enzymatic hydrolysis of lupin protein are able to modulate cholesterol metabolism in human hepatic HepG2 cells and that part of these peptides are absorbed in a small intestine model based on differentiated human Caco-2 cells. In this paper, a co-culture system, including Caco-2 and HepG2 cells, was investigated with two objectives: (a to verify whether cholesterol metabolism in HepG2 cells was modified by the peptides absorption through Caco-2 cells; (b to investigate how lupin peptides influence cholesterol metabolism in Caco-2 cells. The experiments showed that the absorbed peptides, not only maintained their bioactivity on HepG2 cells, but that this activity was improved by the crosstalk of the two cells systems in co-culture. In addition, lupin peptides showed a positive influence on cholesterol metabolism in Caco-2 cells, decreasing the proprotein convertase subtilisin/kexin type 9 (PCSK9 secretion.

  1. Glucose transport by epithelia prepared from harvested enterocytes

    DEFF Research Database (Denmark)

    Kimura, Yasuhiro; van der Merwe, Marie; Bering, Stine Brandt

    2015-01-01

    a simple, novel, and reproducible method for preparing functional epithelia using differentiated enterocytes harvested from the small intestine upper villus of adult mice and preterm pigs with and without necrotizing enterocolitis. Concentrative, rheogenic glucose uptake was used as an indicator...... of epithelial function and was demonstrated by cellular accumulation of tracer (14)C D-glucose and Ussing chamber based short-circuit currents. Assessment of the epithelia by light and immunofluorescent microscopy revealed the harvested enterocytes remain differentiated and establish cell-cell connections...

  2. The effect of exercise on the absorption of inhaled human insulin in healthy volunteers

    DEFF Research Database (Denmark)

    Petersen, Astrid Heide; Kohler, Gerd; Korsatko, Stefan

    2008-01-01

    What is already known about this subject * Exercise is known to affect absorption of other inhaled substances, but so far there are no reports on the effect of exercise on the absorption of inhaled insulin in humans. What this paper adds * This report is the first to investigate the effect...... of exercise on the absorption of inhaled insulin. * In this study in healthy volunteers we found that exercise early after dosing increased absorption (15-20%) of inhaled insulin over the first 2 h after start of exercise, with an approximately 30% increase in maximal insulin concentration, and unchanged...... overall absorption. Aims To investigate the effect of moderate exercise on the absorption of inhaled insulin. Methods A single-centre, randomized, open-label, three-period cross-over trial was carried out in 12 nonsmoking healthy subjects. A dose of 3.5 mg inhaled human insulin was administered via...

  3. Estimation of the Human Absorption Cross Section Via Reverberation Models

    DEFF Research Database (Denmark)

    Steinböck, Gerhard; Pedersen, Troels; Fleury, Bernard Henri

    2018-01-01

    Since the presence of persons affects the reverberation time observed for in-room channels, the absorption cross section of a person can be estimated from measurements via Sabine's and Eyring's models for the reverberation time. We propose an estimator relying on the more accurate model by Eyring...... in the literature. We also suggest the use of controlled environments with low average absorption coefficients to obtain more reliable estimates. The obtained values can be used to predict the change of reverberation time with persons in the propagation environment. This allows prediction of channel characteristics...

  4. Absorption of infrared radiation by human dental hard substances

    Science.gov (United States)

    Roth, Klaus K.; Duczynski, Edwin W.; von der Heide, Hans-Joachim; Struve, Bert

    1993-12-01

    Absorption spectra of enamel, dentin, synthetic hydroxyapatite and deionized water were taken in the wavelength band 500 to 3000 nm. It could be shown that infrared radiation is mainly absorbed in the aqueous components of dental hard tissues. Because of their decreased water content extinctions measured are slightly lower than those of deionized water. Furthermore, mineral absorptions could be detected in the range of 2760 to 2840 nm with a maximum at 2800 nm in enamel and a smaller one at 2500 nm in dentin.

  5. Cinnamon polyphenols regulate multiple metabolic pathways involved in insulin signaling and intestinal lipoprotein metabolism of small intestinal enterocytes.

    Science.gov (United States)

    Qin, Bolin; Dawson, Harry D; Schoene, Norberta W; Polansky, Marilyn M; Anderson, Richard A

    2012-01-01

    Increasing evidence suggests that dietary factors may affect the expression of multiple genes and signaling pathways, which regulate intestinal lipoprotein metabolism. The small intestine is actively involved in the regulation of dietary lipid absorption, intracellular transport, and metabolism and is closely linked to systemic lipid metabolism. Cinnamon polyphenols have been shown to improve glucose, insulin, and lipid metabolism and improve inflammation in cell culture, animal, and human studies. However, little is known of the effects of an aqueous cinnamon extract (CE) on the regulation of genes and signaling pathways related to intestinal metabolism. The aim of the study was to investigate the effects of a CE on the primary enterocytes of chow-fed rats. Freshly isolated intestinal enterocytes were used to investigate apolipoprotein-B48 secretion by immunoprecipitation; gene expressions by quantitative reverse transcriptase-polymerase chain reaction and the protein and phosphorylation levels were evaluated by western blot and flow cytometric analyses. Ex vivo, the CE significantly decreased the amount of apolipoprotein-B48 secretion into the media, inhibited the mRNA expression of genes of the inflammatory cytokines, interleukin-1β, interleukin-6, and tumor necrosis factor-α, and induced the expression of the anti-inflammatory gene, Zfp36. CE also increased the mRNA expression of genes leading to increased insulin sensitivity, including Ir, Irs1, Irs2, Pi3k, and Akt1, and decreased Pten expression. CE also inhibited genes associated with increased cholesterol, triacylglycerols, and apolipoprotein-B48 levels, including Abcg5, Npc1l1, Cd36, Mttp, and Srebp1c, and facilitated Abca1 expression. CE also stimulated the phospho-p38 mitogen-activated protein kinase, c-Jun N-terminal kinase, and extracellular-signal-regulated kinase expressions determined by flow cytometry, with no changes in protein levels. These results demonstrate that the CE regulates genes

  6. Insights into Digestion and Absorption of Major Nutrients in Humans

    Science.gov (United States)

    Goodman, Barbara E.

    2010-01-01

    Nutrient digestion and absorption is necessary for the survival of living organisms and has evolved into the complex and specific task of the gastrointestinal (GI) system. While most people simply assume that their GI tract will work properly to use nutrients, provide energy, and release wastes, few nonscientists know the details about how various…

  7. ABSORPTION-SPECTRA OF HUMAN FETAL AND ADULT OXYHEMOGLOBIN, DE-OXYHEMOGLOBIN, CARBOXYHEMOGLOBIN, AND METHEMOGLOBIN

    NARCIS (Netherlands)

    ZIJLSTRA, WG; MEEUWSENVANDERROEST, WP

    We determined the millimolar absorptivities of the four clinically relevant derivatives of fetal and adult human hemoglobin in the visible and near-infrared spectral range (450-1000 nm). As expected, spectral absorption curves of similar shape were found, but the small differences between fetal and

  8. Absorption of beta-carotene and other carotenoids in humans and animal models : a review

    NARCIS (Netherlands)

    Vliet, T. van

    1996-01-01

    Objective: To review available information on absorption and further metabolism of different carotenoids in man and to discuss animal models and approaches in the study of carotenoid absorption and metabolism in man. Conclusions: Humans appear to absorb various carotenoids in a relatively

  9. Establishment and characterization of partially differentiated chicken enterocyte cell clones.

    Science.gov (United States)

    Velge, Philippe; Bottreau, Elisabeth; Quéré, Pascale; Pardon, Pierre; Nicolle, Jean Claude; Morisson, Mireille; Bout, Daniel; Dimier, Isabelle

    2002-04-01

    Three enterocyte cell clones were established in vitro from the intestine of a PA12 hen embryo. These cells exhibited epithelioid morphology and grew as monolayers. The cells were continuously propagated in culture up to 250 passages. Gradual increase in growth rate with time and in anchorage-independent growth in both agar and agarose showed that the three cell clones spontaneously transformed in vitro. The clones were heteroploid with one marker chromosome. Interestingly, they had features of partly differentiated enterocytes, especially microvilli, junctions connecting adjacent cells (tight junctions, desmosomes, hemidesmosomes, gap junctions), villin and cytokeratins. In addition, cells expressed brush border enzyme activity and transepithelial resistance. The fact that the levels of dipeptidyl peptidase IV (DPP-IV) and alkaline phosphatase activities fluctuated according to culture time and that MHC class II was induced by activation of cells with interferon suggested that the state of differentiation of the 3 cell clones could be modified in vitro. These clones are the first established avian enterocyte cell clones to be described. Because each cell clone exhibited differences in the level of differentiation and sensitivity to Salmonella infection, their use will allow comparative investigations concerning markers of differentiation of avian enterocytes and infection by host-adapted bacteria and parasites.

  10. Enterocyte Proliferation and Signaling Are Constitutively Altered in Celiac Disease

    Science.gov (United States)

    Maglio, Mariantonia; Kosova, Roberta; Sarno, Marco; Gaito, Alessandra; Discepolo, Valentina; Troncone, Riccardo; Auricchio, Salvatore

    2013-01-01

    Celiac disease (CD) occurs frequently, and is caused by ingestion of prolamins from cereals in subjects with a genetic predisposition. The small intestinal damage depends on an intestinal stress/innate immune response to certain gliadin peptides (e.g., A-gliadin P31-43) in association with an adaptive immune response to other gliadin peptides (e.g., A-gliadin P57-68). Gliadin and peptide P31-43 affect epithelial growth factor receptor (EGFR) signaling and CD enterocyte proliferation. The reason why the stress/innate immune and proliferative responses to certain gliadin peptides are present in CD and not in control intestine is so far unknown. The aim of this work is to investigate if, in CD, a constitutive alteration of enterocyte proliferation and signaling exists that may represent a predisposing condition to the damaging effects of gliadin. Immunofluorescence and immunohistochemistry were used to study signaling in CD fibroblasts and intestinal biopsies. Western blot (WB) analysis, immunoprecipitation, and quantitative PCR were also used. We found in CD enterocytes enhancement of both proliferation and Epidermal Growth Factor Receptor (EGFR)/ligand system. In CD enterocytes and fibroblasts we found increase of the phosphorylated downstream signaling molecule Extracellular Signal Regulated Kinase (ERK); block of the ERK activation normalizes enterocytes proliferation in CD mucosa. In conclusion the same pathway, which gliadin and gliadin peptide P31-43 can interfere with, is constitutively altered in CD cells. This observation potentially explains the specificity of the damaging effects of certain gliadin peptides on CD intestine. PMID:24204586

  11. Enterocyte proliferation and signaling are constitutively altered in celiac disease.

    Directory of Open Access Journals (Sweden)

    Merlin Nanayakkara

    Full Text Available Celiac disease (CD occurs frequently, and is caused by ingestion of prolamins from cereals in subjects with a genetic predisposition. The small intestinal damage depends on an intestinal stress/innate immune response to certain gliadin peptides (e.g., A-gliadin P31-43 in association with an adaptive immune response to other gliadin peptides (e.g., A-gliadin P57-68. Gliadin and peptide P31-43 affect epithelial growth factor receptor (EGFR signaling and CD enterocyte proliferation. The reason why the stress/innate immune and proliferative responses to certain gliadin peptides are present in CD and not in control intestine is so far unknown. The aim of this work is to investigate if, in CD, a constitutive alteration of enterocyte proliferation and signaling exists that may represent a predisposing condition to the damaging effects of gliadin. Immunofluorescence and immunohistochemistry were used to study signaling in CD fibroblasts and intestinal biopsies. Western blot (WB analysis, immunoprecipitation, and quantitative PCR were also used. We found in CD enterocytes enhancement of both proliferation and Epidermal Growth Factor Receptor (EGFR/ligand system. In CD enterocytes and fibroblasts we found increase of the phosphorylated downstream signaling molecule Extracellular Signal Regulated Kinase (ERK; block of the ERK activation normalizes enterocytes proliferation in CD mucosa. In conclusion the same pathway, which gliadin and gliadin peptide P31-43 can interfere with, is constitutively altered in CD cells. This observation potentially explains the specificity of the damaging effects of certain gliadin peptides on CD intestine.

  12. Cholesterol induces fetal rat enterocyte death in culture

    Directory of Open Access Journals (Sweden)

    Gazzola J.

    2004-01-01

    Full Text Available The effect of cholesterol on fetal rat enterocytes and IEC-6 cells (line originated from normal rat small intestine was examined. Both cells were cultured in the presence of 20 to 80 µM cholesterol for up to 72 h. Apoptosis was determined by flow cytometric analysis and fluorescence microscopy. The expression of HMG-CoA reductase and peroxisome proliferator-activated receptor gamma (PPARgamma was measured by RT-PCR. The addition of 20 µM cholesterol reduced enterocyte proliferation as early as 6 h of culture. Reduction of enterocyte proliferation by 28 and 41% was observed after 24 h of culture in the presence and absence of 10% fetal calf serum, respectively, with the effect lasting up to 72 h. Treatment of IEC-6 cells with cholesterol for 24 h raised the proportion of cells with fragmented DNA by 9.7% at 40 µM and by 20.8% at 80 µM. When the culture period was extended to 48 h, the effect of cholesterol was still more pronounced, with the percent of cells with fragmented DNA reaching 53.5% for 40 µM and 84.3% for 80 µM. Chromatin condensation of IEC-6 cells was observed after treatment with cholesterol even at 20 µM. Cholesterol did not affect HMG-CoA reductase expression. A dose-dependent increase in PPARgamma expression in fetal rat enterocytes was observed. The expression of PPAR-gamma was raised by 7- and 40-fold, in the presence and absence of fetal calf serum, respectively, with cholesterol at 80 mM. The apoptotic effect of cholesterol on enterocytes was possibly due to an increase in PPARgamma expression.

  13. In vitro dermal absorption of decabromodiphenyl ethane in rat and human skin

    Data.gov (United States)

    U.S. Environmental Protection Agency — In vitro dermal absorption of decabromodiphenyl ethane in rat and human skin. This dataset is associated with the following publication: Knudsen, G., J.M. Sanders,...

  14. Acoustic absorption measurement of human hair and skin within the audible frequency range.

    Science.gov (United States)

    Katz, B F

    2000-11-01

    Utilizing the two-microphone impedance tube method, the acoustic absorption of human skin and hair is measured in the frequency range 1-6 kHz. Various locations on a number of human subjects are measured to determine if the presence of bone or an air pocket affects the acoustic absorption of human skin. The absorption coefficient of human hair is also measured. Additional techniques are utilized to minimize errors due to sample mounting methods. Techniques are employed to minimize potential errors in sensor and sample locations. The results of these measurements are compared to relevant historical papers on similar investigations. Results for skin measurements compare well with previous work. Measured hair absorption data do not agree with previous work in the area but do coincide with expected trends, which previous works do not.

  15. Time Domain Technique for Rapid, Broadband Measurement of Human Absorption Cross Section in a Reverberation Chamber

    OpenAIRE

    Robinson, Martin P; Zhang, Xiaotian; Flintoft, Ian D.

    2017-01-01

    Absorption cross section (ACS) of an object is used in stochastic power balance models, while human ACS is closely related to microwave dosimetry parameters such as specific absorption rate (SAR) and thus characterises exposure as well as effect of human bodies on multipath propagation. ACS, averaged over all directions of incidence, can be obtained in the frequency domain from the S-parameters of two antennas in a stirred-mode reverberation chamber; however, our new time domain method is fas...

  16. Percutaneous absorption of mexoryl SX® in human volunteers: Comparison with in vitro data

    NARCIS (Netherlands)

    Benech-Kieffer, F.; Meuling, W.J.A.; Leclerc, C.; Roza, L.; Leclaire, J.; Nohynek, G.

    2003-01-01

    The potential human health risk of UV filters depends on their toxicity and the human systemic exposure which is a function of the extent of percutaneous absorption of the topically applied substance into the human organism. Using a 'mass balance' approach, a study was designed to investigate the

  17. MRI is unable to illustrate the absorption time of the absorbable TIGR mesh in humans

    DEFF Research Database (Denmark)

    Öberg, Stina; Andresen, Kristoffer; Møller, Jakob M

    2015-01-01

    3 years in sheep. The patient was therefore followed for 3 years by annual magnetic resonance imagings (MRIs) to illustrate the absorption time in humans. During follow-up, the thickness of the absorbable mesh slightly decreased, and at the last clinical examination, the patient was without...... a recurrence. However, MRI failed to illustrate absorption of the TIGR mesh, perhaps since new connective tissue and the mesh material had the same appearance on the images. In conclusion, MRI was unable to confirm an absorption time of 3 years for the TIGR mesh, and further studies are needed to investigate...

  18. A new approach to predict human intestinal absorption using porcine intestinal tissue and biorelevant matrices

    NARCIS (Netherlands)

    Westerhout, J.; Steeg, E. van de; Grossouw, D.; Zeijdner, E.E.; Krul, C.A.M.; Verwei, M.; Wortelboer, H.M.

    2014-01-01

    A reliable prediction of the oral bioavailability in humans is crucial and of high interest for pharmaceutical and food industry. The predictive value of currently used in silico methods, in vitro cell lines, ex vivo intestinal tissue and/or in vivo animal studies for human intestinal absorption,

  19. FDI spillovers, absorptive capacities and human capital development

    DEFF Research Database (Denmark)

    Narula, Rajneesh; Marin, Anabel

    2003-01-01

    spillovers accrue from MNE activity, and provide apreliminary understanding of why MNE spillovers remain somewhat ambiguous,particularly in developing countries, paying particular attention to human capitaldevelopment. Our analysis is supported by data from the Innovation Survey in Argentina.On the whole......It is nowadays generally accepted that inward foreign direct investment (FDI) is crucialas a source of technological spillovers. One of the objectives of this paper is to review theevidence on the quantity and quality of human capital employed by domestic and foreignfirms. We examine whether...

  20. An inulin-type fructan enhances calcium absorption primarily via an effect on colonic absorption in humans

    Science.gov (United States)

    Calcium absorption efficiency and bone mineral mass are increased in adolescents who regularly consume inulin-type fructans (ITF). The mechanism of action in increasing absorption is unknown but may be related to increased colonic calcium absorption. We conducted a study in young adults designed to ...

  1. Nanocrystalline titanium dioxide and magnesium oxide in vitro dermal absorption in human skin.

    Science.gov (United States)

    van der Merwe, Deon; Tawde, Snehal; Pickrell, John A; Erickson, Larry E

    2009-01-01

    The dermal absorption potential of a nanocrystalline magnesium oxide (MgO) and titanium dioxide (TiO(2)) mixture in dermatomed human skin was assessed in vitro using Bronaugh-type flow-through diffusion cells. Nanocrystalline material was applied to the skin surface at a dose rate of 50 mg/cm(2) as a dry powder, as a water suspension, and as a water/surfactant (sodium lauryl sulfate) suspension, for 8 hours. Dermal absorption of nanocrystalline MgO and TiO(2) through human skin with intact, functional stratum corneum was not detectable under the conditions of this experiment.

  2. Water and solute absorption from carbohydrate-electrolyte solutions in the human proximal small intestine: a review and statistical analysis.

    Science.gov (United States)

    Shi, Xiaocai; Passe, Dennis H

    2010-10-01

    The purpose of this study is to summarize water, carbohydrate (CHO), and electrolyte absorption from carbohydrate-electrolyte (CHO-E) solutions based on all of the triple-lumen-perfusion studies in humans since the early 1960s. The current statistical analysis included 30 reports from which were obtained information on water absorption, CHO absorption, total solute absorption, CHO concentration, CHO type, osmolality, sodium concentration, and sodium absorption in the different gut segments during exercise and at rest. Mean differences were assessed using independent-samples t tests. Exploratory multiple-regression analyses were conducted to create prediction models for intestinal water absorption. The factors influencing water and solute absorption are carefully evaluated and extensively discussed. The authors suggest that in the human proximal small intestine, water absorption is related to both total solute and CHO absorption; osmolality exerts various impacts on water absorption in the different segments; the multiple types of CHO in the ingested CHO-E solutions play a critical role in stimulating CHO, sodium, total solute, and water absorption; CHO concentration is negatively related to water absorption; and exercise may result in greater water absorption than rest. A potential regression model for predicting water absorption is also proposed for future research and practical application. In conclusion, water absorption in the human small intestine is influenced by osmolality, solute absorption, and the anatomical structures of gut segments. Multiple types of CHO in a CHO-E solution facilitate water absorption by stimulating CHO and solute absorption and lowering osmolality in the intestinal lumen.

  3. Prediction of Human Intestinal Absorption of Compounds Using Artificial Intelligence Techniques.

    Science.gov (United States)

    Kumar, Rajnish; Sharma, Anju; Siddiqui, Mohammed Haris; Tiwari, Rajesh Kumar

    2017-01-01

    Information about Pharmacokinetics of compounds is an essential component of drug design and development. Modeling the pharmacokinetic properties require identification of the factors effecting absorption, distribution, metabolism and excretion of compounds. There have been continuous attempts in the prediction of intestinal absorption of compounds using various Artificial intelligence methods in the effort to reduce the attrition rate of drug candidates entering to preclinical and clinical trials. Currently, there are large numbers of individual predictive models available for absorption using machine learning approaches. Six Artificial intelligence methods namely, Support vector machine, k- nearest neighbor, Probabilistic neural network, Artificial neural network, Partial least square and Linear discriminant analysis were used for prediction of absorption of compounds. Prediction accuracy of Support vector machine, k- nearest neighbor, Probabilistic neural network, Artificial neural network, Partial least square and Linear discriminant analysis for prediction of intestinal absorption of compounds was found to be 91.54%, 88.33%, 84.30%, 86.51%, 79.07% and 80.08% respectively. Comparative analysis of all the six prediction models suggested that Support vector machine with Radial basis function based kernel is comparatively better for binary classification of compounds using human intestinal absorption and may be useful at preliminary stages of drug design and development. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  4. Proteomic Analysis of Lipid Droplets from Caco-2/TC7 Enterocytes Identifies Novel Modulators of Lipid Secretion

    Science.gov (United States)

    Beilstein, Frauke; Bouchoux, Julien; Rousset, Monique; Demignot, Sylvie

    2013-01-01

    In enterocytes, the dynamic accumulation and depletion of triacylglycerol (TAG) in lipid droplets (LD) during fat absorption suggests that cytosolic LD-associated TAG contribute to TAG-rich lipoprotein (TRL) production. To get insight into the mechanisms controlling the storage/secretion balance of TAG, we used as a tool hepatitis C virus core protein, which localizes onto LDs, and thus may modify their protein coat and decrease TRL secretion. We compared the proteome of LD fractions isolated from Caco-2/TC7 enterocytes expressing or not hepatitis C virus core protein by a differential proteomic approach (isobaric tag for relative and absolute quantitation (iTRAQ) labeling coupled with liquid chromatography and tandem mass spectrometry). We identified 42 proteins, 21 being involved in lipid metabolism. Perilipin-2/ADRP, which is suggested to stabilize long term-stored TAG, was enriched in LD fractions isolated from Caco-2/TC7 expressing core protein while perilipin-3/TIP47, which is involved in LD synthesis from newly synthesized TAG, was decreased. Endoplasmic reticulum-associated proteins were strongly decreased, suggesting reduced interactions between LD and endoplasmic reticulum, where TRL assembly occurs. For the first time, we show that 17β-hydroxysteroid dehydrogenase 2 (DHB2), which catalyzes the conversion of 17-keto to 17 β-hydroxysteroids and which was the most highly enriched protein in core expressing cells, is localized to LD and interferes with TAG secretion, probably through its capacity to inactivate testosterone. Overall, we identified potential new players of lipid droplet dynamics, which may be involved in the balance between lipid storage and secretion, and may be altered in enterocytes in pathological conditions such as insulin resistance, type II diabetes and obesity. PMID:23301014

  5. Development of a chicken enterocyte culture to study its functional physiology

    Science.gov (United States)

    We developed a method to culture chicken intestinal enterocytes, the cells that absorb and form protective barriers against enteric bacteria, to study their functional physiologies. Using intestinal villi, harvested from day old broiler chicks, the enterocytes were isolated by sequential digestion ...

  6. Absorption of anthocyanins from blueberries and serum antioxidant status in human subjects.

    Science.gov (United States)

    Mazza, G; Kay, Colin D; Cottrell, Tony; Holub, Bruce J

    2002-12-18

    In recent years, numerous studies have shown that the polyphenolics present in fruit and vegetable products exhibit a wide range of biological effects. However, there is little reliable information on the absorption of glycosylated and acylated anthocyanins in humans. In the present study, the absorption of anthocyanins in humans was investigated after the consumption of a high-fat meal with a freeze-dried blueberry powder containing 25 individual anthocyanins including 6 acylated structures. Nineteen of the 25 anthocyanins present in the blueberries were detected in human blood serum. Furthermore, the appearance of total anthocyanins in the serum was directly correlated with an increase in serum antioxidant capacity (ORAC(acetone), P blueberries, a food source with high in vitro antioxidant properties, is associated with a diet-induced increase in ex vivo serum antioxidant status.

  7. [Determination of trace cobalt in human urine by graphite furnace atomic absorption spectrometr].

    Science.gov (United States)

    Zhong, L X; Ding, B M; Jiang, D; Liu, D Y; Yu, B; Zhu, B L; Ding, L

    2016-05-20

    To establish a method to determine cobalt in human urine by graphite furnace atomic absorption spectrometry. Urine with 2% nitric acid diluted two-fold, to quantify the curve, graphite furnace atomic absorption spectrometric detection. Co was linear within 2.5~40.0 ng/ml with r>0.999. Spike experiment showed that Co received good recovery rate, which was 90.8%~94.8%. Intra-assay precisions were 3.2%~5.1% for Co, inter-assay precisions were 4.4%~5.2% for Co. The method by using graphite furnace atomic absorption spectrometr to determine urine Co was fast, accurate and with low matrix effect. It could meet the requirement in GBZ/T 210.5-2008.

  8. Anthocyanin Absorption and Metabolism by Human Intestinal Caco-2 Cells--A Review.

    Science.gov (United States)

    Kamiloglu, Senem; Capanoglu, Esra; Grootaert, Charlotte; Van Camp, John

    2015-09-08

    Anthocyanins from different plant sources have been shown to possess health beneficial effects against a number of chronic diseases. To obtain any influence in a specific tissue or organ, these bioactive compounds must be bioavailable, i.e., effectively absorbed from the gut into the circulation and transferred to the appropriate location within the body while still maintaining their bioactivity. One of the key factors affecting the bioavailability of anthocyanins is their transport through the gut epithelium. The Caco-2 cell line, a human intestinal epithelial cell model derived from a colon carcinoma, has been proven to be a good alternative to animal studies for predicting intestinal absorption of anthocyanins. Studies investigating anthocyanin absorption by Caco-2 cells report very low absorption of these compounds. However, the bioavailability of anthocyanins may be underestimated since the metabolites formed in the course of digestion could be responsible for the health benefits associated with anthocyanins. In this review, we critically discuss recent findings reported on the anthocyanin absorption and metabolism by human intestinal Caco-2 cells.

  9. Assessment of intestinal absorption of trace metals in humans by means of stable isotopes.

    Science.gov (United States)

    Werner, E; Roth, P; Höllriegl, V; Hansen, Ch; Kaltwasser, J P; Giussani, A; Cantone, M C; Greim, H; Zilker, T; Felgenhauer, N

    2002-03-01

    This study is aimed to demonstrate the feasibility of stable isotopes for the assessment of reliable data on fractional intestinal absorption of trace metals in healthy humans. Among the various methods available, the double isotope technique, i.e. one isotope given orally together with the test substance to be investigated and another isotope injected intravenously to correct for retention and endogenous excretion of the particular trace metal, provides quantitative figures of intestinal absorption at reasonable expenses with regard to costs for materials and number of samples to be evaluated. The trace metals exemplarily included in this study, i.e. iron, cobalt and molybdenum show diverging relations between absorbed fractions and amounts administered which are indicative for different regulatory mechanisms of their body content. Food ligands influence the fractional absorption significantly so that the uptake from a composite meal cannot be derived from results on uptake from particular foodstuffs. Therefore, validated data on the behaviour of intestinal absorption will significantly contribute to a better understanding of human trace metal metabolism.

  10. Iron metabolism in mynah birds (Gracula religiosa) resembles human hereditary haemochromatosis.

    Science.gov (United States)

    Mete, A; Hendriks, H G; Klaren, P H M; Dorrestein, G M; van Dijk, J E; Marx, J J M

    2003-12-01

    Iron overload is a very frequent finding in several animal species and a genetic predisposition is suggested. In one of the most commonly reported species with susceptibility for iron overload (mynah bird), it was recently shown that the cause of this pathophysiology is high uptake and retention of dietary iron. Here we compare susceptible (mynahs) with non-susceptible avian species (chickens) by evaluating iron uptake at the intestinal absorptive cell level. Enterocytes from mynahs and chickens were isolated and uptake of Fe(II) and Fe(III) was studied in vitro. It was found that Fe(III) uptake is much lower than Fe(II) uptake for both species. Although liver iron, present only in hepatocytes, was at least 10-fold higher in mynahs than chickens, enterocyte Fe(II) uptake was considerably higher in mynahs. Fe(II) uptake showed saturation at the studied concentrations in both species. Kinetic studies revealed a three-fold increase in Vmax for mynahs. Calculated values for the uptake kinetics of the probable membrane transporter suggest that mynah bird enterocytes have a significantly higher limiting uptake rate, due to the possible increase in the number of transporters when compared with chicken enterocytes. The susceptibility of this species is due to intestinal iron uptake despite hepatic iron accumulation, implicating a 'mis-sensing' of body iron similarly to human hereditary haemochromatosis.

  11. Subcutaneous absorption kinetics of two highly concentrated preparations of recombinant human growth hormone

    DEFF Research Database (Denmark)

    Laursen, Torben; Jørgensen, Jens Otto Lunde; Susgaard, Søren

    1993-01-01

    hours. Samples were taken every 30 minutes for 6 hours and then hourly. MAIN OUTCOME MEASURES: Bioavailability (F) and absorption dynamics of human GH were measured. The relative absorption fractions estimated from the areas under the individual serum concentration curves from 0 to 24 hours......Abstract OBJECTIVE: The relative bioavailability of two highly concentrated (12 IU/ml) formulations of biosynthetic human growth hormone (GH) administered subcutaneously was compared. DESIGN: A randomized, crossover study. Conventional GH therapy was withdrawn 72 hours before each study period...... of signs of endogenous GH secretion. INTERVENTIONS: At the start of each study period, GH 3 IU/m2 was injected subcutaneously. The two formulations, PenFill and PenSet, differ in the buffers used and in the relative content of mannitol and glycine. Serum profiles of GH were monitored frequently for 24...

  12. Prediction of Human Intestinal Absorption by GA Feature Selection and Support Vector Machine Regression

    OpenAIRE

    Zongyuan Cai; Zhi Wang; Aixia Yan

    2008-01-01

    QSAR (Quantitative Structure Activity Relationships) models for the prediction of human intestinal absorption (HIA) were built with molecular descriptors calculated by ADRIANA.Code, Cerius2 and a combination of them. A dataset of 552 compounds covering a wide range of current drugs with experimental HIA values was investigated. A Genetic Algorithm feature selection method was applied to select proper descriptors. A Kohonen's self-organizing Neural Network (KohNN) map was used to split the who...

  13. Consensus hologram QSAR modeling for the prediction of human intestinal absorption.

    Science.gov (United States)

    Moda, Tiago L; Andricopulo, Adriano D

    2012-04-15

    Consistent in silico models for ADME properties are useful tools in early drug discovery. Here, we report the hologram QSAR modeling of human intestinal absorption using a dataset of 638 compounds with experimental data associated. The final validated models are consistent and robust for the consensus prediction of this important pharmacokinetic property and are suitable for virtual screening applications. Copyright © 2012 Elsevier Ltd. All rights reserved.

  14. Polyunsaturated fatty acids down-regulate in vitro expression of the key intestinal cholesterol absorption protein NPC1L1: no effect of monounsaturated nor saturated fatty acids.

    Science.gov (United States)

    Alvaro, Adriana; Rosales, Roser; Masana, Lluís; Vallvé, Joan-Carles

    2010-06-01

    Several transporter proteins regulate intestinal cholesterol absorption. Of these proteins, NPC1L1 is a major contributor to this process. Fatty acids (FAs) modulate cholesterol absorption by a mechanism that remains unknown. We evaluate the effect of saturated fatty acids (SFAs), monounsaturated fatty acids (MUFAs) and polyunsaturated fatty acids (PUFAs) on the expression of NPC1L1 and others proteins associated with cholesterol absorption (SR-BI, ABCG5, ABCG8, ABCA1, CAV-1, ANX-2) in human enterocytes in vitro. The role of SREBPs, PPARs, LXR and RXR in this process was also investigated. Caco-2/TC-7 enterocytes were incubated for 24 h with a wide range of concentrations of FA-bovine serum albumin (50-300 microM). Gene expression was analyzed by quantitative real-time PCR. The NPC1L1 protein present in enterocyte membranes was analyzed using Western blot. NPC1L1 mRNA levels were reduced 35-58% by the n-3 PUFAs, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) (PLinoleic acid (n-6), palmitic acid and oleic acid did not affect NPC1L1 mRNA expression. ABCA1 mRNA levels were reduced 44-70% by n-6 arachidonic acid and 43-55% by n-3 EPA (P<.05). LXR and LXR+RXR agonists decreased NPC1L1 mRNA expression by 28% and 57%, respectively (P<.05). A concentration of 200 microM of EPA and DHA decreased NPC1L1 protein expression in enterocyte membranes by 58% and 59%, respectively. We have demonstrated that the PUFAs n-3 EPA and DHA down-regulate NPC1L1 mRNA expression. In addition, PUFAs also down-regulate NPC1L1 protein expression in enterocyte membranes. LXR and RXR activation induced a similar repression effect. The lipid-lowering effect of n-3 PUFAs could be mediated in part by their action at the NPC1L1 gene level. Copyright (c) 2010 Elsevier Inc. All rights reserved.

  15. Quantity of ethanol absorption after excessive hand disinfection using three commercially available hand rubs is minimal and below toxic levels for humans

    National Research Council Canada - National Science Library

    Kramer, Axel; Below, Harald; Bieber, Nora; Kampf, Guenter; Toma, Cyril D; Huebner, Nils-Olaf; Assadian, Ojan

    2007-01-01

    ... when repeatedly applied to human skin. The aim of this study was to assess if ethanol absorption occurs during hygienic and surgical hand disinfection using three different alcohol-based hand-rubs, and to quantify absorption levels in humans...

  16. Effect of the artificial sweetener, sucralose, on small intestinal glucose absorption in healthy human subjects.

    Science.gov (United States)

    Ma, Jing; Chang, Jessica; Checklin, Helen L; Young, Richard L; Jones, Karen L; Horowitz, Michael; Rayner, Christopher K

    2010-09-01

    It has been reported that the artificial sweetener, sucralose, stimulates glucose absorption in rodents by enhancing apical availability of the transporter GLUT2. We evaluated whether exposure of the proximal small intestine to sucralose affects glucose absorption and/or the glycaemic response to an intraduodenal (ID) glucose infusion in healthy human subjects. Ten healthy subjects were studied on two separate occasions in a single-blind, randomised order. Each subject received an ID infusion of sucralose (4 mM in 0.9% saline) or control (0.9% saline) at 4 ml/min for 150 min (T = - 30 to 120 min). After 30 min (T = 0), glucose (25 %) and its non-metabolised analogue, 3-O-methylglucose (3-OMG; 2.5 %), were co-infused intraduodenally (T = 0-120 min; 4.2 kJ/min (1 kcal/min)). Blood was sampled at frequent intervals. Blood glucose, plasma glucagon-like peptide-1 (GLP-1) and serum 3-OMG concentrations increased during ID glucose/3-OMG infusion (P sucralose and control infusions. In conclusion, sucralose does not appear to modify the rate of glucose absorption or the glycaemic or incretin response to ID glucose infusion when given acutely in healthy human subjects.

  17. Biopartitioning micellar chromatography: an in vitro technique for predicting human drug absorption.

    Science.gov (United States)

    Molero-Monfort, M; Escuder-Gilabert, L; Villanueva-Camañas, R M; Sagrado, S; Medina-Hernández, M J

    2001-04-05

    The main oral drug absorption barriers are fluid cell membranes and generally drugs are absorbed by a passive diffusion mechanism. Biopartitioning micellar chromatography (BMC) is a mode of micellar liquid chromatography that uses micellar mobile phases of Brij35 under adequate experimental conditions and can be useful to mimic the drug partitioning process in biological systems. In this paper the usefulness of BMC for predicting oral drug absorption in humans is demonstrated. A hyperbolic model has been obtained using the retention data of a heterogeneous set of 74 compounds, which shows predictive ability for drugs absorbed by passive diffusion. The model obtained in BMC is compared with those obtained using the well-known systems (Caco-2 and TC-7) that use intestinal epithelium cell lines. The use of BMC is simple, reproducible and can provide key information about the transport properties of new compounds during the drug discovery process.

  18. In Silico Prediction for Intestinal Absorption and Brain Penetration of Chemical Pesticides in Humans.

    Science.gov (United States)

    Chedik, Lisa; Mias-Lucquin, Dominique; Bruyere, Arnaud; Fardel, Olivier

    2017-06-30

    Intestinal absorption and brain permeation constitute key parameters of toxicokinetics for pesticides, conditioning their toxicity, including neurotoxicity. However, they remain poorly characterized in humans. The present study was therefore designed to evaluate human intestine and brain permeation for a large set of pesticides ( n = 338) belonging to various chemical classes, using an in silico graphical BOILED-Egg/SwissADME online method based on lipophilicity and polarity that was initially developed for drugs. A high percentage of the pesticides (81.4%) was predicted to exhibit high intestinal absorption, with a high accuracy (96%), whereas a lower, but substantial, percentage (38.5%) displayed brain permeation. Among the pesticide classes, organochlorines ( n = 30) constitute the class with the lowest percentage of intestine-permeant members (40%), whereas that of the organophosphorus compounds ( n = 99) has the lowest percentage of brain-permeant chemicals (9%). The predictions of the permeations for the pesticides were additionally shown to be significantly associated with various molecular descriptors well-known to discriminate between permeant and non-permeant drugs. Overall, our in silico data suggest that human exposure to pesticides through the oral way is likely to result in an intake of these dietary contaminants for most of them and brain permeation for some of them, thus supporting the idea that they have toxic effects on human health, including neurotoxic effects.

  19. Carotenoid absorption from salad and salsa by humans is enhanced by the addition of avocado or avocado oil

    National Research Council Canada - National Science Library

    Unlu, Nuray Z; Bohn, Torsten; Clinton, Steven K; Schwartz, Steven J

    2005-01-01

    .... However, most carotenoid-rich fruits and vegetables are low in lipids. The objective of this study was to assess whether the addition of avocado fruit as a lipid source enhances carotenoid absorption in humans. Healthy subjects (n = 11/study...

  20. Cavity-Enhanced Absorption Spectroscopy and Photoacoustic Spectroscopy for Human Breath Analysis

    Science.gov (United States)

    Wojtas, J.; Tittel, F. K.; Stacewicz, T.; Bielecki, Z.; Lewicki, R.; Mikolajczyk, J.; Nowakowski, M.; Szabra, D.; Stefanski, P.; Tarka, J.

    2014-12-01

    This paper describes two different optoelectronic detection techniques: cavity-enhanced absorption spectroscopy and photoacoustic spectroscopy. These techniques are designed to perform a sensitive analysis of trace gas species in exhaled human breath for medical applications. With such systems, the detection of pathogenic changes at the molecular level can be achieved. The presence of certain gases (biomarkers), at increased concentration levels, indicates numerous human diseases. Diagnosis of a disease in its early stage would significantly increase chances for effective therapy. Non-invasive, real-time measurements, and high sensitivity and selectivity, capable of minimum discomfort for patients, are the main advantages of human breath analysis. At present, monitoring of volatile biomarkers in breath is commonly useful for diagnostic screening, treatment for specific conditions, therapy monitoring, control of exogenous gases (such as bacterial and poisonous emissions), as well as for analysis of metabolic gases.

  1. Greater apparent absorption of flavonoids is associated with lesser human fecal flavonoid disappearance rates.

    Science.gov (United States)

    Simons, Andrean L; Renouf, Mathieu; Murphy, Patricia A; Hendrich, Suzanne

    2010-01-13

    It was hypothesized that 5,7,4'-OH-flavonoids disappeared more rapidly from human fecal incubations and were less absorbable by humans than flavonoids without 5-OH moieties. Anaerobic fecal disappearance rates over 24 h were determined for 15 flavonoids in samples from 20 men and 13 women. In these anaerobic fecal mixtures, flavonoids with 5,7,4'-OH groups, genistein, apigenin, naringenin, luteolin, kaempferol, and quercetin (disappearance rate, k=0.46+/-0.10 h(-1)), and methoxylated flavonoids, hesperetin and glycitein (k=0.24+/-0.21 h(-1)), disappeared rapidly compared with flavonoids lacking 5-OH (e.g., daidzein, k=0.07+/-0.03 h(-1)). Apparent absorption of flavonoids that disappeared rapidly from in vitro fecal incubations, genistein, naringenin, quercetin, and hesperetin, was compared with that of daidzein, a slowly disappearing flavonoid, in 5 men and 5 women. Subjects ingested 104 micromol of genistein and 62 micromol of daidzein (soy milk), 1549 micromol of naringenin and 26 micromol of hesperetin (grapefruit juice), and 381 micromol of quercetin (onions) in three test meals, each separated by 1 week. Blood and urine samples were collected over 24 h after each test meal. Plasma flavonoid concentrations ranged from 0.01 to 1 microM. The apparent absorption, expressed as percentage of ingested dose excreted in urine, was significantly less for naringenin (3.2+/-1.7%), genistein (7.2+/-4.6%), hesperetin (7.3+/-3.2%), and quercetin (5.6+/-3.7%) compared with daidzein (43.4+/-15.5%, p=0.02). These data affirmed the hypothesis that the 5,7,4'-OH of flavonoids limited apparent absorption of these compounds in humans.

  2. Dermal absorption behavior of fluorescent molecules in nanoparticles on human and porcine skin models.

    Science.gov (United States)

    Debotton, Nir; Badihi, Amit; Robinpour, Mano; Enk, Claes D; Benita, Simon

    2017-05-30

    The percutaneous passage of poorly skin absorbed molecules can be improved using nanocarriers, particularly biodegradable polymeric nanospheres (NSs) or nanocapsules (NCs). However, penetration of the encapsulated molecules may be affected by other factors than the nanocarrier properties. To gain insight information on the skin absorption of two fluorescent cargos, DiIC18(5) and coumarin-6 were incorporated in NSs or NCs and topically applied on various human and porcine skin samples. 3D imaging techniques suggest that NSs and NCs enhanced deep dermal penetration of both probes similarly, when applied on excised human skin irrespective of the nature of the cargo. However, when ex vivo pig skin was utilized, the cutaneous absorption of DiIC18(5) was more pronounced by means of PLGA NCs than NSs. In contrast, PLGA NSs noticeably improved the porcine skin penetration of coumarin-6, as compared to the NCs. Furthermore, the porcine skin results were reproducible when triplicated whereas from various human skin samples, as expected, the results were not sufficiently reproducible and large deviations were observed. The overall findings from this comprehensive comparison emphasize the potential of PLGA NCs or NSs to promote cutaneous bioavailability of encapsulated drugs, exhibiting different physicochemical properties but depending on the nature of the skin. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Human in vivo and in vitro studies on gastrointestinal absorption of titanium dioxide nanoparticles.

    Science.gov (United States)

    Jones, Kate; Morton, Jackie; Smith, Ian; Jurkschat, Kerstin; Harding, Anne-Helen; Evans, Gareth

    2015-03-04

    The study was designed to conduct human in vivo and in vitro studies on the gastrointestinal absorption of nanoparticles, using titanium dioxide as a model compound, and to compare nanoparticle behaviour with that of larger particles. A supplier's characterisation data may not fully describe a particle formulation. Most particles tested agreed with their supplied characterisation when assessed by particle number but significant proportions of 'nanoparticle formulations' were particles >100nm when assessed by particle weight. Oral doses are measured by weight and it is therefore important that the weight characterisation is taken into consideration. The human volunteer studies demonstrated that very little titanium dioxide is absorbed gastrointestinally after an oral challenge. There was no demonstrable difference in absorption for any of the three particle sizes tested. All tested formulations were shown to agglomerate in simulated gastric fluid, particularly in the smaller particle formulations. Further agglomeration was observed when dispersing formulations in polymeric or elemental foods. Virtually no translocation of titanium dioxide particles across the cell layer was demonstrated. This study found no evidence that nanoparticulate titanium dioxide is more likely to be absorbed in the gut than micron-sized particles. Crown Copyright © 2015. Published by Elsevier Ireland Ltd. All rights reserved.

  4. Fungal Deoxynivalenol-Induced Enterocyte Distress Is Attenuated by Adulterated Adlay: In Vitro Evidences for Mucoactive Counteraction

    Directory of Open Access Journals (Sweden)

    Zhimin Du

    2018-02-01

    Full Text Available Adlay is a cereal crop that has long been used as traditional herbal medicine and as a highly nourishing food. However, deoxynivalenol (DON, the most prevalent trichothecene mycotoxin worldwide, frequently spoils grains, including adlay, via fungal infection. On the basis of an assumption that the actions of DON in the gut could be modified by adlay consumption, we simulated the impacts of co-exposure in enterocytes and investigated the effectiveness of treatment with adlay for reducing the risk of DON-induced inflammation and epithelia barrier injury. In particular, adlay suppressed DON-induced pro-inflammatory signals such as mitogen-activated kinase transduction and the epidermal growth factor receptor-linked pathway. In addition to regulation of pro-inflammatory responses, adlay treatment interfered with DON-induced disruption of the epithelial barrier. Mechanistically, adlay could boost the activation of protein kinase C (PKC and cytosolic translocation of human antigen R (HuR protein, which played critical roles in the epithelial restitution, resulting in protection against disruption of enterocyte barrier integrity. Notably, DON abrogated the Ras homolog gene family member A GTPase-mediated actin cytoskeletal network, which was diminished by adlay treatment in PKC and HuR-dependent ways. Taken together, this study provides evidences for adlay-based attenuation of trichothecene-induced gut distress, implicating potential use of a new gut protector against enteropathogenic insults in diets.

  5. Linoleic acid uptake by isolated enterocytes: influence of alpha-linolenic acid on absorption.

    Science.gov (United States)

    Goré, J; Hoinard, C; Couet, C

    1994-10-01

    In a previous study we showed that intestinal uptake of alpha-linolenic acid (18:3n-3) was carrier-mediated and we suggested that a plasma membrane fatty acid protein was involved in the transport of long-chain fatty acids. To further test this hypothesis, the mechanism of linoleic acid (18:2n-6) uptake by isolated intestinal cells was examined using a rapid filtration method and 20 mM sodium taurocholate as solubilizing agent. Under these experimental conditions transport of [1-14C]linoleic acid monomers in the concentration range of 2 to 2220 nM was saturable with a Vm of 5.1 +/- 0.6 nmol/mg protein/min and a Km of 183 +/- 7 nM. Experiments carried out in the presence of metabolic inhibitors, such as 2,4-dinitrophenol and antimycin A, suggested that an active, carrier-mediated mechanism was involved in the intestinal uptake of this essential fatty acid. The addition of excess unlabeled linoleic acid to the incubation medium led to a 89% decrease in the uptake of [1-14C]linoleic acid, while D-glucose did not compete for transport into the cell. Other long-chain polyunsaturated fatty acids added to the incubation mixture inhibited linoleic acid uptake by more than 80%. The presence of alpha-linolenic acid (18:3n-3) in the incubation medium caused the competitive inhibition (Ki = 353 nM) of linoleic acid uptake. The data are compatible with the hypothesis that intestinal uptake of both linoleic, and alpha-linolenic acid is mediated by a membrane carrier common to long-chain fatty acids.

  6. Dietary hemoglobin rescues young piglets from severe iron deficiency anemia: Duodenal expression profile of genes involved in heme iron absorption.

    Directory of Open Access Journals (Sweden)

    Robert Staroń

    Full Text Available Heme is an efficient source of iron in the diet, and heme preparations are used to prevent and cure iron deficiency anemia in humans and animals. However, the molecular mechanisms responsible for heme absorption remain only partially characterized. Here, we employed young iron-deficient piglets as a convenient animal model to determine the efficacy of oral heme iron supplementation and investigate the pathways of heme iron absorption. The use of bovine hemoglobin as a dietary source of heme iron was found to efficiently counteract the development of iron deficiency anemia in piglets, although it did not fully rebalance their iron status. Our results revealed a concerted increase in the expression of genes responsible for apical and basolateral heme transport in the duodenum of piglets fed a heme-enriched diet. In these animals the catalytic activity of heme oxygenase 1 contributed to the release of elemental iron from the protoporphyrin ring of heme within enterocytes, which may then be transported by the strongly expressed ferroportin across the basolateral membrane to the circulation. We hypothesize that the well-recognized high bioavailability of heme iron may depend on a split pathway mediating the transport of heme-derived elemental iron and intact heme from the interior of duodenal enterocytes to the bloodstream.

  7. Deep-apical tubules: dynamic lipid-raft microdomains in the brush-border region of enterocytes.

    OpenAIRE

    Hansen, Gert H.; Pedersen, Jens,; Niels-Christiansen, Lise-Lotte; Immerdal, Lissi; Danielsen, E. Michael

    2003-01-01

    The brush border of small intestinal enterocytes is highly enriched in cholesterol- and glycosphingolipid-containing membrane microdomains, commonly termed as lipid 'rafts'. Functionally, transcytosis of IgA and exocytosis of newly made brush-border proteins in enterocytes occur through apical lipid raft-containing compartments, but little is otherwise known about these raft microdomains. We therefore studied in closer detail apical lipid-raft compartments in enterocytes by immunogold electro...

  8. Differential Expression of the Activator Protein 1 Transcription Factor Regulates Interleukin-1ß Induction of Interleukin 6 in the Developing Enterocyte.

    Directory of Open Access Journals (Sweden)

    Catherine M Cahill

    Full Text Available The innate immune response is characterized by activation of transcription factors, nuclear factor kappa B and activator protein-1 and their downstream targets, the pro-inflammatory cytokines including interleukin 1β and interleukin 6. Normal development of this response in the intestine is critical to survival of the human neonate and delays can cause the onset of devastating inflammatory diseases such as necrotizing enterocolitis. Previous studies have addressed the role of nuclear factor kappa B in the development of the innate immune response in the enterocyte, however despite its central role in the control of multiple pro-inflammatory cytokine genes, little is known on the role of Activator Protein 1 in this response in the enterocyte. Here we show that the canonical Activator Protein 1 members, cJun and cFos and their upstream kinases JNK and p38 play an essential role in the regulation of interleukin 6 in the immature enterocyte. Our data supports a model whereby the cFos/cJun heterodimer and the more potent cJun homodimer downstream of JNK are replaced by less efficient JunD containing dimers, contributing to the decreased responsiveness to interleukin 1β and decreased interleukin 6 secretion observed in the mature enterocyte. The tissue specific expression of JunB in colonocytes and colon derived tissues together with its ability to repress Interleukin-1β induction of an Interleukin-6 gene reporter in the NCM-460 colonocyte suggests that induction of JunB containing dimers may offer an attractive therapeutic strategy for the control of IL-6 secretion during inflammatory episodes in this area of the intestine.

  9. Absorption of 308-nm excimer laser radiation by balanced salt solution, sodium hyaluronate, and human cadaver eyes

    Energy Technology Data Exchange (ETDEWEB)

    Keates, R.H.; Bloom, R.T.; Schneider, R.T.; Ren, Q.; Sohl, J.; Viscardi, J.J. (Univ. of California, Irvine (USA))

    1990-11-01

    Absorption of the excimer laser radiations of 193-nm argon fluorine and 308-nm xenon chloride in balanced salt solution, sodium hyaluronate, and human cadaver eyes was measured. The absorption of these materials as considerably different for the two wavelengths; we found that 308-nm light experienced much less absorption than the 193-nm light. The extinction coefficient (k) for 308 nm was k = 0.19/cm for balanced salt solution and k = 0.22/cm for sodium hyaluronate. In contrast to this, the extinction coefficient for 193 nm was k = 140/cm for balanced salt solution and k = 540/cm for sodium hyaluronate. Two 1-day-old human phakic cadaver eyes showed complete absorption with both wavelengths. Using aphakic eyes, incomplete absorption was noted at the posterior pole with 308 nm and complete absorption was noted with 193 nm. The extinction in the anterior part of aphakic eyes (the first 6 mm) was 4.2/cm for 308 nm, meaning that the intensity of the light is reduced by a factor of 10 after traveling the first 5.5 mm. However, we observed that the material in the eye fluoresces, meaning the 308 nm is transformed into other (longer) wavelengths that travel through the total eye with minimal absorption. Conclusions drawn from this experiment are that the use of the 308-nm wavelength may have undesirable side effects, while the use of the 193-nm wavelength should be consistent with ophthalmic use on both the cornea and the lens.

  10. Investigation of human teeth with respect to the photon interaction, energy absorption and buildup factor

    Energy Technology Data Exchange (ETDEWEB)

    Kurudirek, Murat, E-mail: mkurudirek@gmail.co [Faculty of Science, Department of Physics, Ataturk University, 25240 Erzurum (Turkey); Topcuoglu, Sinan [Faculty of Dentistry, Department of Endodontic, Ataturk University, 25240 Erzurum (Turkey)

    2011-05-15

    The effective atomic numbers and electron densities of human teeth have been calculated for total photon interaction (Z{sub PI{sub e{sub f{sub f}}}},Ne{sub PI{sub e{sub f{sub f}}}}) and photon energy absorption (Z{sub PEA{sub e{sub f{sub f}}}},Z{sub RW{sub e{sub f{sub f}}}}Ne{sub PEA{sub e{sub f{sub f}}}}) in the energy region 1 keV-20 MeV. Besides, the energy absorption (EABF) and exposure (EBF) buildup factors have been calculated for these samples by using the geometric progression fitting approximation in the energy region 0.015-15 MeV up to 40 mfp (mean free path). Wherever possible the results were compared with experiment. Effective atomic numbers (Z{sub PI{sub e{sub f{sub f}}}}) of human teeth were calculated using different methods. Discrepancies were noted in Z{sub PI{sub e{sub f{sub f}}}} between the direct and interpolation methods in the low and high energy regions where absorption processes dominate while good agreement was observed in intermediate energy region where Compton scattering dominates. Significant variations up to 22% were observed between Z{sub PI{sub e{sub f{sub f}}}} and Z{sub PEA{sub e{sub f{sub f}}}} in the energy region 30-150 keV which is the used energy range in dental cone beam computed tomography (CBCT) X-ray machines. The Z{sub eff} values of human teeth were found to relatively vary within 1% if different laser treatments are applied. In this variation, the Er:YAG laser treated samples were found to be less effected than Nd:YAG laser treated ones when compared with control group. Relative differences between EABF and EBF were found to be significantly high in the energy region 60 keV-1 MeV even though they have similar variations with respect to the different parameters viz. photon energy, penetration depth.

  11. CNTF mediates neurotrophic factor secretion and fluid absorption in human retinal pigment epithelium.

    Directory of Open Access Journals (Sweden)

    Rong Li

    Full Text Available Ciliary neurotrophic factor (CNTF protects photoreceptors and regulates their phototransduction machinery, but little is known about CNTF's effects on retinal pigment epithelial (RPE physiology. Therefore, we determined the expression and localization of CNTF receptors and the physiological consequence of their activation in primary cultures of human fetal RPE (hfRPE. Cultured hfRPE express CNTF, CT1, and OsM and their receptors, including CNTFRα, LIFRβ, gp130, and OsMRβ, all localized mainly at the apical membrane. Exogenous CNTF, CT1, or OsM induces STAT3 phosphorylation, and OsM also induces the phosphorylation of ERK1/2 (p44/42 MAP kinase. CNTF increases RPE survivability, but not rates of phagocytosis. CNTF increases secretion of NT3 to the apical bath and decreases that of VEGF, IL8, and TGFβ2. It also significantly increases fluid absorption (J(V across intact monolayers of hfRPE by activating CFTR chloride channels at the basolateral membrane. CNTF induces profound changes in RPE cell biology, biochemistry, and physiology, including the increase in cell survival, polarized secretion of cytokines/neurotrophic factors, and the increase in steady-state fluid absorption mediated by JAK/STAT3 signaling. In vivo, these changes, taken together, could serve to regulate the microenvironment around the distal retinal/RPE/Bruch's membrane complex and provide protection against neurodegenerative disease.

  12. CNTF mediates neurotrophic factor secretion and fluid absorption in human retinal pigment epithelium.

    Science.gov (United States)

    Li, Rong; Wen, Rong; Banzon, Tina; Maminishkis, Arvydas; Miller, Sheldon S

    2011-01-01

    Ciliary neurotrophic factor (CNTF) protects photoreceptors and regulates their phototransduction machinery, but little is known about CNTF's effects on retinal pigment epithelial (RPE) physiology. Therefore, we determined the expression and localization of CNTF receptors and the physiological consequence of their activation in primary cultures of human fetal RPE (hfRPE). Cultured hfRPE express CNTF, CT1, and OsM and their receptors, including CNTFRα, LIFRβ, gp130, and OsMRβ, all localized mainly at the apical membrane. Exogenous CNTF, CT1, or OsM induces STAT3 phosphorylation, and OsM also induces the phosphorylation of ERK1/2 (p44/42 MAP kinase). CNTF increases RPE survivability, but not rates of phagocytosis. CNTF increases secretion of NT3 to the apical bath and decreases that of VEGF, IL8, and TGFβ2. It also significantly increases fluid absorption (J(V)) across intact monolayers of hfRPE by activating CFTR chloride channels at the basolateral membrane. CNTF induces profound changes in RPE cell biology, biochemistry, and physiology, including the increase in cell survival, polarized secretion of cytokines/neurotrophic factors, and the increase in steady-state fluid absorption mediated by JAK/STAT3 signaling. In vivo, these changes, taken together, could serve to regulate the microenvironment around the distal retinal/RPE/Bruch's membrane complex and provide protection against neurodegenerative disease.

  13. Inhibiting Cholesterol Absorption During Lactation Programs Future Intestinal Absorption of Cholesterol in Adult Mice.

    Science.gov (United States)

    Dimova, Lidiya G; de Boer, Jan Freark; Plantinga, Josee; Plösch, Torsten; Hoekstra, Menno; Verkade, Henkjan J; Tietge, Uwe J F

    2017-08-01

    In nematodes, the intestine senses and integrates early life dietary cues that lead to lifelong epigenetic adaptations to a perceived nutritional environment-it is not clear whether this process occurs in mammals. We aimed to establish a mouse model of reduced dietary cholesterol availability from maternal milk and investigate the consequences of decreased milk cholesterol availability, early in life, on the metabolism of cholesterol in adult mice. We blocked intestinal absorption of cholesterol in milk fed to newborn mice by supplementing the food of dams (for 3 weeks between birth and weaning) with ezetimibe, which is secreted into milk. Ezetimibe interacts with the intestinal cholesterol absorption transporter NPC1l1 to block cholesterol uptake into enterocytes. Characterization of these offspring at 24 weeks of age showed a 27% decrease in cholesterol absorption (P < .001) and reduced levels of Npc1l1 messenger RNA and protein, but not other cholesterol transporters, in the proximal small intestine. We observed increased histone H3K9me3 methylation at positions -423 to -607 of the proximal Npc1l1 promoter in small intestine tissues from 24-week-old offspring fed ezetimibe during lactation, compared with controls. These findings show that the early postnatal mammalian intestine functions as an environmental sensor of nutritional conditions, responding to conditions such as low cholesterol levels by epigenetic modifications of genes. Further studies are needed to determine how decreased sterol absorption for a defined period might activate epigenetic regulators; the findings of our study might have implications for human infant nutrition and understanding and preventing cardiometabolic disease. Copyright © 2017 AGA Institute. Published by Elsevier Inc. All rights reserved.

  14. Vinegar lacks antiglycemic action on enteral carbohydrate absorption in human subjects.

    Science.gov (United States)

    Salbe, Arline D; Johnston, Carol S; Buyukbese, M Akif; Tsitouras, Panayiotis D; Harman, S Mitchell

    2009-12-01

    The antiglycemic effects of vinegar have been known for more than a century and have been demonstrated in animal as well as human studies. Although the exact mechanism of vinegar action is not known, several possibilities have been proposed including suppression of disaccharidase activity, delayed gastric emptying, enhanced glucose uptake in the periphery and conversion to glycogen, and increased satiety. We hypothesized that by suppressing endogenous insulin secretion, we could estimate the glucose absorption rate from an oral carbohydrate load and determine the effects of vinegar ingestion on this rate. To do so, 5 subjects had 4 studies at 1-week intervals, randomly receiving placebo twice (60 mL water) and vinegar twice (20 mL apple cider vinegar, 40 mL water), followed 2 minutes later by a meal of mashed potatoes (0.75 g carbohydrate per kilogram body weight) that was consumed over 20 minutes. At the beginning of the meal, an oral octreotide/insulin suppression test (25-microg bolus octreotide; 180 minute infusion 5 mU/m(2) body surface area per minute regular human insulin, and 0.5 microg/min octreotide) was begun. Blood samples for insulin and glucose were drawn at 20-minute intervals. The oral octreotide/insulin suppression test suppressed endogenous insulin secretion for the first 100 minutes of the study. During this time, the rate of rise of glucose was modestly but significantly (P = .01) greater after vinegar ingestion compared to placebo, suggesting that vinegar does not act to decrease glycemia by interference with enteral carbohydrate absorption.

  15. N-acetylcysteine inhibits Na+ absorption across human nasal epithelial cells.

    Science.gov (United States)

    Rochat, Thierry; Lacroix, Jean-Silvain; Jornot, Lan

    2004-10-01

    N-acetylcysteine (NAC) is a widely used mucolytic drug in patients with a variety of respiratory disorders. The mechanism of action is based on rupture of the disulfide bridges of the high molecular glycoproteins present in the mucus, resulting in smaller subunits of the glycoproteins and reduced viscosity of the mucus. Because Na(+) absorption regulates airway surface liquid volume and thus the efficiency of mucociliary clearance, we asked whether NAC affects the bioelectric properties of human nasal epithelial cells. A 24-h basolateral treatment with 10 mM of NAC decreased the transepithelial potential difference and short-circuit current (I(SC)) by 40%, and reduced the amiloride-sensitive current by 50%, without affecting the transepithelial resistance. After permeabilization of the basolateral membranes of cells with amphotericin B in the presence of a mucosal-to-serosal Na(+) gradient (135:25 mM), NAC inhibited 45% of the amiloride-sensitive current. The Na(+)-K(+)-ATPase pump activity and the basolateral K(+) conductance were not affected by NAC treatment. NAC did not alter total cell mRNA and protein levels of alpha-epithelial Na(+) channel (EnaC) subunit, but reduced abundance of alpha-ENaC subunits in the apical cell membrane as quantified by biotinylation. This effect can be ascribed to the sulphydryl (SH) group of NAC, since N-acetylserine and S-carboxymethyl-l-cysteine were ineffective. Given the importance of epithelial Na(+) channels in controlling the thin layer of fluid that covers the surface of the airways, the increase in the fluidity of the airway mucus following NAC treatment in vivo might be in part related to downregulation of Na(+) absorption and consequently water transport.

  16. Human systemic exposure to a [14C]-para-phenylenediamine- containing oxidative hair dye and correlation with in vitro percutaneous absorption in human or pig skin

    NARCIS (Netherlands)

    Hueber-Becker, F.; Nohynek, G.J.; Meuling, W.J.A.; Benech-Kieffer, F.; Toutain, H.

    2004-01-01

    We investigated the absorption of a commercial [14C]-PPD- containing oxidative dark-shade hair dye in human volunteers as well as in vitro using human or pig ear skin. The hair of eight male volunteers was cut to a standard length, dyed, washed, dried, clipped and collected. Hair, washing water,

  17. Simultaneous Pharmacokinetic Modeling of Alkylresorcinols and Their Main Metabolites Indicates Dual Absorption Mechanisms and Enterohepatic Elimination in Humans

    DEFF Research Database (Denmark)

    Marklund, Matti; Strömberg, Eric A,; Lærke, Helle Nygaard

    2014-01-01

    a single dose (120 g) of rye bran and validated against fasting plasma concentrations from 8 women and 7 men with controlled rye bran intake (23, 45, or 90 g/d). Alkylresorcinols in the lymph and plasma of a pig fed a single alkylresorcinol dose (1.3 mmol) were quantified to assess absorption. Human...... of absorbed alkylresorcinols was metabolized before reaching the systemic circulation. Plasma concentrations of alkylresorcinols and their metabolites depended on absorption and formation, respectively, and the mean ± SEM terminal elimination half-life of alkylresorcinols (1.9 ± 0.59 h), DHPPA (1.5 ± 0.26 h......% of the alkylresorcinol dose was recovered in the lymph. DHPPA was identified in both human ileostomal effluent and pig bile, indicating availability of DHPPA for absorption and enterohepatic circulation.Conclusion: Intact alkylresorcinols have advantages over DHBA and DHPPA as plasma biomarkers for whole-grain wheat...

  18. Absorption, conjugation and excretion of the flavanones, naringenin and hesperetin from alpha-rhamnosidase-treated orange juice in human subjects

    DEFF Research Database (Denmark)

    Bredsdorff, Lea; Nielsen, I.L.F.; Rasmussen, S.E.

    2010-01-01

    We have determined the absorption, conjugation and excretion of naringenin-7-O-rutinosicle (narirutin) compared to the corresponding glucoside in an orange juice matrix in human subjects. Healthy volunteers (eight men and eight women), in a double blind, randomised, crossover study, consumed oran...

  19. sup 125 I-albumin may not be used as a tracer of absorption across the human nasal airway bassiers

    Energy Technology Data Exchange (ETDEWEB)

    Greiff, L.; Pipkorn, U. (Lund Univ. Hospital (Sweden). Dept. of Oto-Rhino-Laryngology); Wollmer, P. (Lund Univ. Hospital (Sweden). Dept. of Clinical Physiology); Persson, C.G.A. (Lund Univ. Hospital (Sweden). Dept. of Clinical Pharmacology)

    1991-01-01

    This study set out to examine the effects of histamine on airway absorption of macromolecules. By employment of a novel 'nasal pool' technique instillates containing {sup 125}I-albumin with or without histamine, were kept for 15 min on human nasal mucosa. Unaffected by the presence of histamine, this instillations produced significant levels of plasma radioactivity, increasing for 60 min. However, gel-filtration data showed that only 30% of the plasma radioactivity was still bound to albumin. Incubation experiments indicated that radioiodine did not dissociate from albumin in nasal liquids nor in the blood. Further experiments involved oral ingestion of the entire nasal instillate. Prompts gastrointestinal absorption of radioactivity occurred, giving rise to plasma levels about two orders of magnitude higher than those recorded after the nasal applications. Moreover, only 25% of the plasma radioactivity was now bound to albumin. It must be considered unavoidable that a small portion (<1%) of the nasal instillate is swallowed. Hence, the plasma radioactivity detected in this study may largely, reflect gastrointestinal break-down of {sup 125}I-albumin and subsequent absorption of radioiodine. We conclude that {sup 125}I-albumin may not be employed in studies addressing macromolecular absorption across the human nasal mucosa and that previous work and conclusions based on nasal absorption of {sup 125}I-albumin are invalid. (au).

  20. Carotenoid absorption from salad and salsa by humans is enhanced by the addition of avocado or avocado oil.

    Science.gov (United States)

    Unlu, Nuray Z; Bohn, Torsten; Clinton, Steven K; Schwartz, Steven J

    2005-03-01

    Dietary lipids are hypothesized to be an important factor for carotenoid bioavailability. However, most carotenoid-rich fruits and vegetables are low in lipids. The objective of this study was to assess whether the addition of avocado fruit as a lipid source enhances carotenoid absorption in humans. Healthy subjects (n = 11/study) were recruited for 2 crossover, postprandial studies. The effect of avocado addition (150 g) to salsa on lycopene and beta-carotene absorption was examined in Study 1, and the absorption of lutein, alpha-carotene, and beta-carotene from salad in Study 2. Furthermore, the effects of avocado dose (75 vs. 150 g containing 12 vs. 24 g lipid, respectively) and of lipid source (avocado fruit vs. avocado oil) on carotenoid absorption were examined in Study 2. Intact carotenoids were quantified in the plasma triacylglycerol-rich lipoprotein (TRL) fraction during the 9.5 h after consumption of the test meal and expressed as baseline-corrected area under the concentration-vs.-time curve (AUC). The addition of avocado to salsa enhanced lycopene and beta-carotene absorption (P avocado-free salsa, respectively. In Study 2, supplementing 150 g avocado or 24 g avocado oil to salad similarly enhanced alpha-carotene, beta-carotene, and lutein absorption (P avocado-free salad, respectively (150 g avocado). Neither the avocado dose nor the lipid source affected carotenoid absorption. In conclusion, adding avocado fruit can significantly enhance carotenoid absorption from salad and salsa, which is attributed primarily to the lipids present in avocado.

  1. Energy absorption buildup factors of human organs and tissues at energies and penetration depths relevant for radiotherapy and diagnostics

    DEFF Research Database (Denmark)

    Manohara, S. R.; Hanagodimath, S. M.; Gerward, Leif

    2011-01-01

    . With the proper knowledge of buildup factors of human organs and tissues, energy absorption in the human body can be carefully controlled. The present results will help in estimating safe dose levels for radiotherapy patients and also useful in diagnostics and dosimetry. The tissue-equivalent materials...... of human organs and tissues changes significantly with the change of incident photon energy and effective atomic number, Zeff. These changes are due to the dominance of different photon interaction processes in different energy regions and different chemical compositions of human organs and tissues...

  2. A Review on Level of Specific Absorption Rate Due to High Power Transmission Lines: Analysis toward Human Position Posture

    Directory of Open Access Journals (Sweden)

    Ghazali Z.

    2016-01-01

    Full Text Available The main contribution of this project is the development of a homogeneous model of a man to presents the specific absorption rate (SAR due to high power transmission line. As a low frequency application under high power transmission line of 50 Hz in electrical engineering, to studies the influence of human’s posture on specific absorption rate. This project designs two types of human body which one design uses most cylinder block and another design use brick block where both blocks have a different value of mesh cells. For each design has four types of posture are standing, sitting, arms up and arms out by using Computer Simulation Technology (CST Studio Software. This analysis does toward for four types of the human position postures because each posture has different value of specific absorption rate (SAR based on the size of the mesh cells of the design. Based on two designs of the human body, the lowest of the mesh cells value will reduce time to simulate SAR. For each posture has different value of SAR for each part of the human body because the whole human body has different types of tissues. Therefore, the CST studio software uses extremely to simulate the SAR value toward human position posture due to high power transmission line.

  3. ANALYSIS ABSORPTION CAPACITY OF EUROPEAN FUNDS UNDER THE OPERATIONAL PROGRAMME HUMAN RESOURCES DEVELOPMENT

    Directory of Open Access Journals (Sweden)

    DANIELA FLORESCU

    2013-10-01

    Full Text Available One of the main goals of the European Union is the economic progress. In the last 50 years, and especially beginning with the ‘80s, remarkable efforts have been made for removing the borders between the EU national economies and for creating a unique market where goods, persons, capital and services could move freely. Commercial interchanges between UE states have significantly grown and at the same time EU has become a global commercial force. EU’s goal is to become the most dynamic economy based on global recognition. This implies a significant investment in research, education and forming, which allows the population to have access to this new information. This research work displays diverse aspects concerning the Romania’s ability draw of irredeemable funds in period 2007 – 2013, focusing on human capital development activity. Today, the problem absorptions are no longer able to develop projects, that knowing a significant improvement but the stage of implementation and funding.

  4. New human milk fat substitutes from butterfat to improve fat absorption

    DEFF Research Database (Denmark)

    Li, Yanqi; Mu, Huiling; Andersen, Jens Enevold Thaulov

    2010-01-01

    the two groups fed LCPUFA in their diet were lower than those without supplementation of LCPUFA, suggesting that LCPUFA could improve calcium absorption by reducing the calcium excretion. It can thus be concluded that the butterfat-based HMFS improves fat absorption, and supplementation of LCPUFA...

  5. Quantity of ethanol absorption after excessive hand disinfection using three commercially available hand rubs is minimal and below toxic levels for humans

    OpenAIRE

    Kramer, Axel; Below, Harald; Bieber, Nora; Kampf, Guenter; Toma, Cyril D; Huebner, Nils-Olaf; Assadian, Ojan

    2007-01-01

    Abstract Background Despite the increasing promotion of alcohol-based hand rubs and the worldwide use of ethanol-based hand rubs in hospitals only few studies have specifically addressed the issue of ethanol absorption when repeatedly applied to human skin. The aim of this study was to assess if ethanol absorption occurs during hygienic and surgical hand disinfection using three different alcohol-based hand-rubs, and to quantify absorption levels in humans. Methods Twelve volunteers applied t...

  6. Cholesterol depletion of enterocytes. Effect on the Golgi complex and apical membrane trafficking

    DEFF Research Database (Denmark)

    Hansen, Gert Helge; Niels-Christiansen, L L; Thorsen, Evy

    2000-01-01

    membrane trafficking in enterocytes. Cultured mucosal explants of pig small intestine were treated for 2 h with the cholesterol sequestering agent methyl-beta-cyclodextrin and lovastatin, an inhibitor of hydroxymethylglutaryl-coenzyme A reductase. The treatment reduced the cholesterol content >50...

  7. Lipid rafts exist as stable cholesterol-independent microdomains in the brush border membrane of enterocytes

    DEFF Research Database (Denmark)

    Hansen, Gert Helge; Immerdal, Lissi; Thorsen, Evy

    2001-01-01

    antibodies were preferentially captured by beads coated with the respective antibody (p removed >70...... rafts, on microvillar vesicles from the enterocyte brush border membrane. Magnetic beads coated with either anti-galectin-4 or anti-lactase antibodies were used for immunoisolation of vesicles followed by double immunogold labeling of the two proteins. A morphometric analysis revealed subpopulations...

  8. Cholera toxin entry into pig enterocytes occurs via a lipid raft- and clathrin-dependent mechanism

    DEFF Research Database (Denmark)

    Hansen, Gert H; Dalskov, Stine-Mathilde; Rasmussen, Christina Rehné

    2005-01-01

    The small intestinal brush border is composed of lipid raft microdomains, but little is known about their role in the mechanism whereby cholera toxin gains entry into the enterocyte. The present work characterized the binding of cholera toxin B subunit (CTB) to the brush border and its...

  9. Brief communication: Soybean meal-induced uptake block in Atlantic salmon Salmo salar distal enterocytes

    NARCIS (Netherlands)

    Urán, P.; Aydin, R.; Schrama, J.W.; Verreth, J.A.J.; Rombout, J.H.W.M.

    2008-01-01

    Soybean meal-induced enteritis was characterized by the disappearance of the supranuclear vacuoles (SNV) in the enterocytes of the distal intestine of Atlantic salmon Salmo salar. The loss of SNV was correlated with an endocytosis uptake block as shown with ferritin as a marker molecule.

  10. Polyunsaturated fatty acid metabolism in enterocyte models: T84 cell line vs. Caco-2 cell line.

    Science.gov (United States)

    Beguin, Pauline; Schneider, Anne-Catherine; Mignolet, Eric; Schneider, Yves-Jacques; Larondelle, Yvan

    2014-02-01

    Human colon carcinoma cell lines such as Caco-2 cells, model of mature enterocytes and T84 cells, model of crypt cells are useful to study interactions between nutrient processing and metabolic functions at intestinal level. Our study aimed at comparing the ability of Caco-2 and T84 cells (1) to incorporate dietary polyunsaturated fatty acids (PUFA), (2) to process them and (3) to sort them into neutral lipids (NL), free fatty acids (FFA) and phospholipids (PL). Caco-2 and T84 cells were exposed to a 7-day long supplementation with PUFA. The amounts of fatty acids accumulated and incorporated into the NL, FFA or PL fractions were higher in Caco-2 than in T84 cells. Caco-2 cells were able to significantly elongate C18 PUFA and C20 PUFA of both n-3 and n-6 families. In contrast, T84 cells were unable to elongate the n-6 fatty acids whereas elongation of n-3 fatty acids was detectable but marginal. Similarly, a Δ6 desaturase activity was observed in Caco-2 but not in T84 cells. In T84 cells, each exogenous fatty acid was predominantly accumulated in the PL fraction. In Caco-2 cells, C20 fatty acids and C18:2n-6 was preferentially accumulated in the PL fraction, while C22 PUFA and C18:3n-3 was preferentially accumulated in the NL fraction. Overall, this study has shown that Caco-2 and T84 cells, as models of intestinal mucosal cells, present large differences in PUFA accumulation capacity, specific elongase and desaturase activities and distribution pattern of exogenous PUFA and of their metabolites in the lipid classes.

  11. 24-hour human urine and serum profiles of bisphenol A: Evidence against sublingual absorption following ingestion in soup.

    Science.gov (United States)

    Teeguarden, Justin G; Twaddle, Nathan C; Churchwell, Mona I; Yang, Xiaoxia; Fisher, Jeffrey W; Seryak, Liesel M; Doerge, Daniel R

    2015-10-15

    Extensive first-pass metabolism of ingested bisphenol A (BPA) in the gastro-intestinal tract and liver restricts blood concentrations of bioactive BPA to <1% of total BPA in humans and non-human primates. Absorption of ingested BPA through non-metabolizing tissues of the oral cavity, recently demonstrated in dogs, could lead to the higher serum BPA concentrations reported in some human biomonitoring studies. We hypothesized that the extensive interaction with the oral mucosa by a liquid matrix, like soup, relative to solid food or capsules, might enhance absorption through non-metabolizing oral cavity tissues in humans, producing higher bioavailability and higher serum BPA concentrations. Concurrent serum and urine concentrations of d6-BPA, and its glucuronide and sulfate conjugates, were measured over a 24hour period in 10 adult male volunteers following ingestion of 30μg d6-BPA/kg body weight in soup. Absorption of d6-BPA was rapid (t1/2=0.45h) and elimination of the administered dose was complete 24h post-ingestion, evidence against any tissue depot for BPA. The maximum serum d6-BPA concentration was 0.43nM at 1.6h after administration and represented <0.3% of total d6-BPA. Pharmacokinetic parameters, pharmacokinetic model simulations, and the significantly faster appearance half-life of d6-BPA-glucuronide compared to d6-BPA (0.29h vs 0.45h) were evidence against meaningful absorption of BPA in humans through any non-metabolizing tissue (<1%). This study confirms that typical exposure to BPA in food produces picomolar to subpicomolar serum BPA concentrations in humans, not nM concentrations reported in some biomonitoring studies. Published by Elsevier Inc.

  12. Narrative absorption

    DEFF Research Database (Denmark)

    Narrative Absorption brings together research from the social sciences and Humanities to solve a number of mysteries: Most of us will have had those moments, of being totally absorbed in a book, a movie, or computer game. Typically we do not have any idea about how we ended up in such a state. No...

  13. Inhibition of duodenal enterocyte Mg2+-ATPase by arachidonic acid is not mediated by an effect on protein kinase C.

    Science.gov (United States)

    Haag, M; Leonard, F; Magada, O N; Kruger, M C

    2000-03-01

    Active absorption processes in the duodenal enterocyte are driven by various ATPases. It is known that the activity of Na+,K+-ATPase, Ca2+-ATPase and Mg2+-ATPase can be modulated by polyunsaturated fatty acids of the n-6 series, for example by linoleic and gamma-linolenic acids. These effects may be achieved by protein phosphorylation via protein kinase C. The present study was undertaken to determine the effect of arachidonic acid on Mg2+-ATPase (measured colorimetrically) activity in basolateral membranes prepared from rat duodenum. It shows, for the first time, significant dose-dependent inhibition of Mg2+-ATPase (26-62%) by arachidonic acid (10-50 microg/ml) which already takes place after one minute of exposure, indicating involvement of a rapid signal transduction mechanism. Addition of the protein kinase C inhibitors bisimidolylmaleimide (2.5 microM) and calphostin (0.5 microM) did not influence the action of arachidonic acid on Mg2+-ATPase; protein kinase C involvement in this process is thus not indicated.

  14. Absorption and effect of the magnesium content of a mineral water in the human body.

    Science.gov (United States)

    Kiss, Sandor A; Forster, Tamás; Dongó, Agnes

    2004-12-01

    The kinetics of magnesium (Mg) absorption, after drinking Magnesia mineral water (204 mg Mg/L), was investigated in healthy humans aged (23-60 yrs). Serum Mg, calcium (Ca), potassium (K) and sodium (Na) content, blood hemoglobin, erythrocyte and white blood cell counts as well as urinary volume and urine Mg content were evaluated. Subjects drank 1.5 liters of Magnesia in 30 minutes; blood and the other tests were taken at 0, 2, 6, 24 and 48 hours, and after 1, 2, 3 and 4 weeks. Serum ion quotient was calculated. Serum Mg levels increased in all cases, and returned to individual normal values after 48 hrs. Subjects drank copious amounts of the mineral water only on the first two days, later they consumed one glass of mineral water at a time, totalling 1-1.5 liters daily. Urinary volume and its Mg content significantly increased, with individual differences in urine Mg content depending on degrees of tissue Mg deficiency. For example, two subjects, who had the same initial serum Mg levels (79 m/M/L), responded to consumption of Magnesia mineral water similarly, with comparable rise of serum Mg but with different urinary Mg excretion, one rapidly excreting Mg, while the other lost less Mg over a longer period of time. The retention of more Mg in one than the other suggests that she had a "hidden" tissue Mg deficiency, despite a serum Mg level within normal limits. No subject experienced ECG or rhythm disturbance, and blood pressure remained unchanged during the study. One patient developed diarrhea. Magnesia's high Mg (204 mg/M) and low Na (5.4 mg/L) content makes it an excellent source of Mg for patients suffering from heart problems and/or high blood pressure.

  15. Predicting human intestinal absorption of diverse chemicals using ensemble learning based QSAR modeling approaches.

    Science.gov (United States)

    Basant, Nikita; Gupta, Shikha; Singh, Kunwar P

    2016-04-01

    Human intestinal absorption (HIA) of the drugs administered through the oral route constitutes an important criterion for the candidate molecules. The computational approach for predicting the HIA of molecules may potentiate the screening of new drugs. In this study, ensemble learning (EL) based qualitative and quantitative structure-activity relationship (SAR) models (gradient boosted tree, GBT and bagged decision tree, BDT) have been established for the binary classification and HIA prediction of the chemicals, using the selected molecular descriptors. The structural diversity of the chemicals and the nonlinear structure in the considered data were tested by the similarity index and Brock-Dechert-Scheinkman statistics. The external predictive power of the developed SAR models was evaluated through the internal and external validation procedures recommended in the literature. All the statistical criteria parameters derived for the performance of the constructed SAR models were above their respective thresholds suggesting for their robustness for future applications. In complete data, the qualitative SAR models rendered classification accuracy of >99%, while the quantitative SAR models yielded correlation (R(2)) of >0.91 between the measured and predicted HIA values. The performances of the EL-based SAR models were also compared with the linear models (linear discriminant analysis, LDA and multiple linear regression, MLR). The GBT and BDT SAR models performed better than the LDA and MLR methods. A comparison of our models with the previously reported QSARs for HIA prediction suggested for their better performance. The results suggest for the appropriateness of the developed SAR models to reliably predict the HIA of structurally diverse chemicals and can serve as useful tools for the initial screening of the molecules in the drug development process. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. Zinc absorption in humans from meals based on rye, barley, oatmeal, triticale and whole wheat

    Energy Technology Data Exchange (ETDEWEB)

    Sandstroem, B.A.; Almgren, A.; Kivistoe, B.C.; Cederblad, A.

    1987-11-01

    The absorption of zinc from meals based on 60 g of rye, barley, oatmeal, triticale or whole wheat was studied by use of extrinsic labelling with /sup 65/Zn and measurement of the whole-body retention of the radionuclide. The cereals were prepared in the form of bread or porridge and were served with 200 mL of milk. The oatmeal flakes were also served without further preparation. The absorption of zinc was negatively correlated to the phytic acid content of the meal with the highest absorption, 26.8 +/- 7.4%, from the rye bread meal containing 100 mumol of phytic acid and the lowest, 8.4 +/- 1.0%, from oatmeal porridge with a phytic acid content of 600 mumol. It is concluded that food preparation that decreases the phytic acid content improves zinc absorption.

  17. Zinc absorption in humans from meals based on rye, barley, oatmeal, triticale and whole wheat.

    Science.gov (United States)

    Sandström, B; Almgren, A; Kivistö, B; Cederblad, A

    1987-11-01

    The absorption of zinc from meals based on 60 g of rye, barley, oatmeal, triticale or whole wheat was studied by use of extrinsic labelling with 65Zn and measurement of the whole-body retention of the radionuclide. The cereals were prepared in the form of bread or porridge and were served with 200 mL of milk. The oatmeal flakes were also served without further preparation. The absorption of zinc was negatively correlated to the phytic acid content of the meal with the highest absorption, 26.8 +/- 7.4%, from the rye bread meal containing 100 mumol of phytic acid and the lowest, 8.4 +/- 1.0%, from oatmeal porridge with a phytic acid content of 600 mumol. It is concluded that food preparation that decreases the phytic acid content improves zinc absorption.

  18. The rule of unity for human intestinal absorption 2: application to pharmaceutical drugs that are marketed as salts.

    Science.gov (United States)

    Patel, Raj B; Admire, Brittany; Yalkowsky, Samuel H

    2015-01-01

    The efficiency of the human intestinal absorption (HIA) of the 59 drugs which are marketed as salts is predicted using the rule of unity. Intrinsic aqueous solubilities and partition coefficients along with the drug dose are used to calculate modified absorption potential (MAP) values. These values are shown to be related to the fraction of the dose that is absorbed upon oral administration in humans (FA). It is shown that the MAP value can distinguish between drugs that are poorly absorbed (FA drugs. This forms the basis of a simple rule of unity based solely on in vitro data for predicting whether or not a drug will be well absorbed at a given dose.

  19. Fluid absorption related to ion transport in human airway epithelial spheroids

    DEFF Research Database (Denmark)

    Pedersen, P S; Holstein-Rathlou, N H; Larsen, P L

    1999-01-01

    , and amiloride inhibited both values. Fluid transport rates were calculated from repeated measurements of spheroid diameters. The results showed that 1) non-CF and CF spheroids absorbed fluid at identical rates (4.4 microl x cm(-2) x h(-1)), 2) amiloride inhibited fluid absorption to a lower residual level...... in non-CF than in CF spheroids, 3) Cl(-)-channel inhibitors increased fluid absorption in amiloride-treated non-CF spheroids to a level equal to that of amiloride-treated CF spheroids, 4) hydrochlorothiazide reduced the amiloride-insensitive fluid absorption in both non-CF and CF spheroids, and 5......) osmotic water permeabilities were equal in non-CF and CF spheroids ( approximately 27 x 10(-7) cm x s(-1) x atm(-1))....

  20. The manifestation of optical centers in UV-Vis absorption and luminescence spectra of white blood human cells

    Science.gov (United States)

    Terent'yeva, Yu G.; Yashchuk, V. M.; Zaika, L. A.; Snitserova, O. M.; Losytsky, M. Yu

    2016-12-01

    A white blood human cells spectral investigation is presented. The aim of this series of experiments was to obtain and analyze the absorption and luminescence (fluorescence and phosphorescence) spectra at room temperature and at 78 K of newly isolated white blood human cells and their organelles. As a result the optical centers and possible biochemical components that form the studied spectra where identified. Also the differences between the spectra of abnormal cells (B-cell chronic lymphocytic leukemia BCLL) and normal ones were studied for the whole cells and individual organelles.

  1. Activation of peroxisome proliferator-activated receptor-{alpha} (PPAR{alpha}) suppresses postprandial lipidemia through fatty acid oxidation in enterocytes

    Energy Technology Data Exchange (ETDEWEB)

    Kimura, Rino [Laboratory of Molecular Function of Food, Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Uji, Kyoto 611-0011 (Japan); Takahashi, Nobuyuki, E-mail: nobu@kais.kyoto-u.ac.jp [Laboratory of Molecular Function of Food, Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Uji, Kyoto 611-0011 (Japan); Murota, Kaeko [Department of Life Science, School of Science and Engineering, Kinki University, Osaka 770-8503 (Japan); Yamada, Yuko [Laboratory of Physiological Function of Food, Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Uji, Kyoto 611-0011 (Japan); Niiya, Saori; Kanzaki, Noriyuki; Murakami, Yoko [Laboratory of Molecular Function of Food, Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Uji, Kyoto 611-0011 (Japan); Moriyama, Tatsuya [Department of Applied Cell Biology, Graduate School of Agriculture, Kinki University, Nara 631-8505 (Japan); Goto, Tsuyoshi; Kawada, Teruo [Laboratory of Molecular Function of Food, Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Uji, Kyoto 611-0011 (Japan)

    2011-06-24

    Highlights: {yields} PPAR{alpha} activation increased mRNA expression levels of fatty acid oxidation-related genes in human intestinal epithelial Caco-2 cells. {yields} PPAR{alpha} activation also increased oxygen consumption rate and CO{sub 2} production and decreased secretion of triglyceride and ApoB from Caco-2 cells. {yields} Orally administration of bezafibrate increased mRNA expression levels of fatty acid oxidation-related genes and CO{sub 2} production in small intestinal epithelial cells. {yields} Treatment with bezafibrate decreased postprandial serum concentration of triglyceride after oral injection of olive oil in mice. {yields} It suggested that intestinal lipid metabolism regulated by PPAR{alpha} activation suppresses postprandial lipidemia. -- Abstract: Activation of peroxisome proliferator-activated receptor (PPAR)-{alpha} which regulates lipid metabolism in peripheral tissues such as the liver and skeletal muscle, decreases circulating lipid levels, thus improving hyperlipidemia under fasting conditions. Recently, postprandial serum lipid levels have been found to correlate more closely to cardiovascular diseases than fasting levels, although fasting hyperlipidemia is considered an important risk of cardiovascular diseases. However, the effect of PPAR{alpha} activation on postprandial lipidemia has not been clarified. In this study, we examined the effects of PPAR{alpha} activation in enterocytes on lipid secretion and postprandial lipidemia. In Caco-2 enterocytes, bezafibrate, a potent PPAR{alpha} agonist, increased mRNA expression levels of fatty acid oxidation-related genes, such as acyl-CoA oxidase, carnitine palmitoyl transferase, and acyl-CoA synthase, and oxygen consumption rate (OCR) and suppressed secretion levels of both triglycerides and apolipoprotein B into the basolateral side. In vivo experiments revealed that feeding high-fat-diet containing bezafibrate increased mRNA expression levels of fatty acid oxidation-related genes and

  2. Intestinal surfactant-like material. A novel secretory product of the rat enterocyte.

    Science.gov (United States)

    DeSchryver-Kecskemeti, K; Eliakim, R; Carroll, S; Stenson, W F; Moxley, M A; Alpers, D H

    1989-01-01

    Surface-active phospholipid-containing particles are traditionally considered to be the product of type II pneumocytes. We now demonstrate membrane-bound lamellar cytoplasmic organelles in adult and suckling rat enterocytes that are densely reactive with phospholipid-staining reagents. These structures were seen in the basolateral space, within the intercellular junctions, and unraveling on the lumenal surface, and were more abundant after fat feeding. Light scrapings of intestinal mucosa and lumenal washings that contained these bodies, as evidenced by morphology and biochemical analysis, lowered surface tension in a pulsating bubble assay. Production by normal enterocytes of material with surfactant-like appearance and properties demonstrates that these structures are present in extrapulmonary epithelia, and extends the possible range of their function beyond gaseous exchange, e.g., solute exchange or lubrication on membrane surfaces. Images PMID:2794067

  3. Foreign direct investment spillovers, absorptive capacities and human capital development : evidence from Argentina

    OpenAIRE

    Narula, Rajneesh; Marin, Anabel

    2005-01-01

    Queries whether developing countries really benefit in terms of technology by attracting multinational enterprises through tax advantages and other benefits. Finds, in the case of Argentina, that a significant technology spillover does not occur automatically, but would require domestic investment in absorptive capacities like training or new equipment.

  4. Effect of room absorption on human vocal output in multitalker situations

    NARCIS (Netherlands)

    Nijs, L.; Saher, K.; Den Ouden, D.

    2008-01-01

    People increase their vocal output in noisy environments. This is known as the Lombard effect. The aim of the present study was to measure the effect as a function of the absorption coefficient. The noise source was generated by using other talkers in the room. A-weighted sound levels were measured

  5. Acute Copper and Ascorbic Acid Supplementation Inhibits Non-heme Iron Absorption in Humans.

    Science.gov (United States)

    Olivares, Manuel; Figueroa, Constanza; Pizarro, Fernando

    2016-08-01

    The objective of the study is to determine the effect of copper (Cu) plus the reducing agent ascorbic acid (AA) on the absorption of non-heme iron (Fe). Experimental study with block design in which each subject was his own control. After signing an informed consent, 14 adult women using an effective method of contraception and negative pregnancy test received 0.5 mg Fe, as ferrous sulfate, alone or with Cu, as copper sulfate, plus ascorbic acid (AA/Cu 2/1 molar ratio) at 4/1; 6/1 and 8/1 Cu/Fe molar ratios as an aqueous solution on days 1, 2, 14, and 15 of the study. Fe absorption was assessed by erythrocyte incorporation of iron radioisotopes (55)Fe and (59)Fe. Geometric mean (range ± SD) absorption of Fe at 4/1 and 6/1 Cu/Fe molar ratios (and AA/Cu 2/1 molar ratio) and Fe alone was 57.4 % (35.7-92.1 %), 64.2 % (45.8-89.9 %), and 38.8 % (20.4-73.8 %), respectively (ANOVA for repeated measures p ascorbic acid inhibits non-heme Fe absorption at Cu/Fe 8/1 molar ratio.

  6. Effect of ammonia in cigarette tobacco on nicotine absorption in human smokers

    NARCIS (Netherlands)

    Amsterdam, van J.; Sleijffers, A.; Spiegel, van P.; Blom, R.; Witte, M.; Kassteele, van de J.; Blokland, M.H.; Steerenberg, P.; Opperhuizen, A.

    2011-01-01

    The function of ammonia as tobacco additive is subject of scientific debate. It is argued that ammonia, by increasing the proportion of free nicotine, increases the absorption of nicotine in smokers. As a result of the addition of ammonia to cigarettes, smokers get exposed to higher internal

  7. Enterocyte apoptosis after enterectomy in mice is activated independent of the extrinsic death receptor pathway.

    Science.gov (United States)

    Knott, Andrew W; O'Brien, David P; Juno, Russell J; Zhang, Yufang; Williams, Jodi L; Erwin, Christopher R; Warner, Brad W

    2003-08-01

    Intestinal adaptation following small bowel resection (SBR) is associated with greater rates of enterocyte apoptosis by unknown mechanism(s). Because postresection adaptation is associated with increased translocation of luminal bacteria, we sought to characterize the role for the extrinsic, death receptor pathway for the activation of enterocyte apoptosis after massive SBR. We first performed SBR or sham operations in mice, and the temporal expression of caspases 8, 9, and 3, death receptors tumor necrosis factor receptor-1 (TNFR1) and Fas and corresponding ligands (TNF and Fas ligand) was determined in the remnant intestine at various postoperative time points. Ileal TNFR1 and Fas expression were then measured after SBR in the setting of increased (waved-2 mice) or decreased (exogenous EGF administration) apoptosis. Finally, intestinal adaptation and apoptosis were recorded in the remnant ileum after SBR in TNFR1-null and Fas-null mice. The expression of death receptor family proteins and caspases demonstrated only modest changes after SBR and did not correlate with the histological appearance of apoptosis. In the setting of accelerated apoptosis, TNFR1 and Fas expression were paradoxically decreased. Apoptotic and adaptive responses were preserved in both TNFR1-null and Fas-null mice. These results suggest that the mechanism for increased enterocyte apoptosis following massive SBR does not appear to involve the extrinsic, death receptor-mediated pathway.

  8. The intestinal absorption of dietary cholesterol by hypercholesterolemic (type II) and normocholesterolemic humans.

    Science.gov (United States)

    Connor, W E; Lin, D S

    1974-04-01

    The incomplete absorption of dietary cholesterol may represent an adaptive intestinal barrier that prevents hypercholesterolemia. To explore this mechanism, we compared cholesterol absorption in 15 normocholesterolemic and 6 hypercholesterolemic (type II) subjects fed background cholesterol-free formula diets with 40% of calories as fat. Each test meal consisted of a breakfast into which was incorporated scrambled egg yolk containing 300-500 mg of cholesterol and [4-(14)C]cholesterol (3-22 muCi), either naturally incorporated into the yolk cholesterol by previous isotope injection into the laying hen or added in peanut oil to the yolk of the test breakfast. In some instances [1alpha-(3)H]cholesterol was the radioactive marker. The radioactivity of the fecal neutral sterol fraction was determined in daily stool samples for the next 7 days to provide an estimate of unabsorbed dietary cholesterol. The amount of absorbed and reexcreted labeled cholesterol proved negligible. Most unabsorbed dietary cholesterol appeared in the stool on the second or third day after the meal, and 95% or more was recovered in the stool by 6 days. Plasma specific activity curves were usually maximal at 48 h. Normal subjects absorbed 44.5+/-9.3 (SD) of the administered cholesterol (range 25.9-60.3). Hypercholesterolemics absorbed the same percentage of cholesterol as normals: 47.6+/-12.6% (range 29.3-67.3). Absorption was similar whether the radiolabeled cholesterol was added to egg yolk or naturally incorporated in it (42.1+/-9.3 vs. 48.9+/-9.8%). Six normal subjects were fed a cholesterol-free formula for 4 wk, and then different amounts of cholesterol (110-610 mg/day) were added for another 4 wk. At the end of each period, single test meals containing either 110, 310, or 610 mg of cholesterol and [1alpha-(3)H]cholesterol were administered. Cholesterol absorption was 42.3+/-6.0% and 45.4+/-8.3% for the two dietary periods, respectively. The absolute cholesterol absorption was linearly

  9. Drug marker absorption in relation to pellet size, gastric motility and viscous meals in humans

    Science.gov (United States)

    Rhie, J. K.; Hayashi, Y.; Welage, L. S.; Frens, J.; Wald, R. J.; Barnett, J. L.; Amidon, G. E.; Putcha, L.; Amidon, G. L.

    1998-01-01

    PURPOSE: The objective of this study was to evaluate drug marker absorption in relation to the gastric emptying (GE) of 0.7 mm and 3.6 mm enteric coated pellets as a function of viscosity and the underlying gastric motility. METHODS: Twelve subjects were evaluated in a 3-way crossover study. 0.7 mm caffeine and 3.6 mm acetaminophen enteric coated pellets were concurrently administered with a viscous caloric meal at the levels of 4000, 6000 and 8000 cP. Gastric motility was simultaneously measured with antral manometry and compared to time events in the plasma profiles of the drug markers. RESULTS: Caffeine, from the 0.7 mm pellets, was observed significantly earlier in the plasma than acetaminophen, from the 3.6 mm pellets, at all levels of viscosity. Motility related size differentiated GE was consistently observed at all viscosity levels, however, less variability was observed with the 4000 cP meal. Specifically, the onset of absorption from the of 3.6 mm pellets correlated with the onset of Phase II fasted state contractions (r = 0.929, p < 0.01). CONCLUSIONS: The timeframe of drug marker absorption and the onset of motility events were not altered within the range of viscosities evaluated. Rather, the differences in drug marker profiles from the non-digestible solids were most likely the result of the interaction between viscosity and motility influencing antral flow dynamics. The administration of the two sizes of pellets and a viscous caloric meal with subsequent monitoring of drug marker profiles is useful as a reference to assess the influence of motility patterns on the absorption profile of orally administered agents.

  10. Quantitative photoacoustic integrating sphere (QPAIS) platform for absorption coefficient and Grüneisen parameter measurements: Demonstration with human blood.

    Science.gov (United States)

    Villanueva-Palero, Yolanda; Hondebrink, Erwin; Petersen, Wilma; Steenbergen, Wiendelt

    2017-06-01

    Quantitative photoacoustic imaging in biomedicine relies on accurate measurements of relevant material properties of target absorbers. Here, we present a method for simultaneous measurements of the absorption coefficient and Grüneisen parameter of small volume of liquid scattering and absorbing media using a coupled-integrating sphere system which we refer to as quantitative photoacoustic integrating sphere (QPAIS) platform. The derived equations do not require absolute magnitudes of optical energy and pressure values, only calibration of the setup using aqueous ink dilutions is necessary. As a demonstration, measurements with blood samples from various human donors are done at room and body temperatures using an incubator. Measured absorption coefficient values are consistent with known oxygen saturation dependence of blood absorption at 750 nm, whereas measured Grüneisen parameter values indicate variability among five different donors. An increasing Grüneisen parameter value with both hematocrit and temperature is observed. These observations are consistent with those reported in literature.

  11. Determining the refractive index of human hemoglobin solutions by Kramers-Kronig relations with an improved absorption model.

    Science.gov (United States)

    Gienger, Jonas; Groß, Hermann; Neukammer, Jörg; Bär, Markus

    2016-11-01

    The real part of the refractive index of aqueous solutions of human hemoglobin is computed from their absorption spectra in the wavelength range 250-1100 nm using the Kramers-Kronig (KK) relations, and the corresponding uncertainty analysis is provided. The strong ultraviolet (UV) and infrared absorbance of the water outside this spectral range were taken into account in a previous study employing KK relations. We improve these results by including the concentration dependence of the water absorbance as well as by modeling the deep UV absorbance of hemoglobin's peptide backbone. The two free parameters of the model for the deep UV absorbance are fixed by a global fit.

  12. MicroRNA mir-16 is anti-proliferative in enterocytes and exhibits diurnal rhythmicity in intestinal crypts

    Energy Technology Data Exchange (ETDEWEB)

    Balakrishnan, Anita, E-mail: anita.balakrishnan@doctors.org.uk [Department of Surgery, Brigham and Women' s Hospital, Boston, MA 02115 (United States); Department of Surgery, Harvard Medical School, Boston, MA 02115 (United States); School of Clinical Sciences, Division of Gastroenterology, University of Liverpool, Liverpool L69 3GE (United Kingdom); Stearns, Adam T. [Department of Surgery, Brigham and Women' s Hospital, Boston, MA 02115 (United States); Department of Surgery, Harvard Medical School, Boston, MA 02115 (United States); Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 2JD (United Kingdom); Park, Peter J. [Department of Medicine, Brigham and Women' s Hospital, Boston, MA 02115 (United States); Harvard Medical School, Center for Biomedical Informatics, Boston, MA 02115 (United States); Dreyfuss, Jonathan M. [Department of Medicine, Brigham and Women' s Hospital, Boston, MA 02115 (United States); Ashley, Stanley W. [Department of Surgery, Brigham and Women' s Hospital, Boston, MA 02115 (United States); Department of Surgery, Harvard Medical School, Boston, MA 02115 (United States); Rhoads, David B. [Department of Surgery, Harvard Medical School, Boston, MA 02115 (United States); Pediatric Endocrine Unit, MassGeneral Hospital for Children, Boston, MA 02114 (United States); Tavakkolizadeh, Ali, E-mail: atavakkoli@partners.org [Department of Surgery, Brigham and Women' s Hospital, Boston, MA 02115 (United States); Department of Surgery, Harvard Medical School, Boston, MA 02115 (United States)

    2010-12-10

    Background and aims: The intestine exhibits profound diurnal rhythms in function and morphology, in part due to changes in enterocyte proliferation. The regulatory mechanisms behind these rhythms remain largely unknown. We hypothesized that microRNAs are involved in mediating these rhythms, and studied the role of microRNAs specifically in modulating intestinal proliferation. Methods: Diurnal rhythmicity of microRNAs in rat jejunum was analyzed by microarrays and validated by qPCR. Temporal expression of diurnally rhythmic mir-16 was further quantified in intestinal crypts, villi, and smooth muscle using laser capture microdissection and qPCR. Morphological changes in rat jejunum were assessed by histology and proliferation by immunostaining for bromodeoxyuridine. In IEC-6 cells stably overexpressing mir-16, proliferation was assessed by cell counting and MTS assay, cell cycle progression and apoptosis by flow cytometry, and cell cycle gene expression by qPCR and immunoblotting. Results: mir-16 peaked 6 hours after light onset (HALO 6) with diurnal changes restricted to crypts. Crypt depth and villus height peaked at HALO 13-14 in antiphase to mir-16. Overexpression of mir-16 in IEC-6 cells suppressed specific G1/S regulators (cyclins D1-3, cyclin E1 and cyclin-dependent kinase 6) and produced G1 arrest. Protein expression of these genes exhibited diurnal rhythmicity in rat jejunum, peaking between HALO 11 and 17 in antiphase to mir-16. Conclusions: This is the first report of circadian rhythmicity of specific microRNAs in rat jejunum. Our data provide a link between anti-proliferative mir-16 and the intestinal proliferation rhythm and point to mir-16 as an important regulator of proliferation in jejunal crypts. This function may be essential to match proliferation and absorptive capacity with nutrient availability.

  13. Effect of room absorption on human vocal output in multitalker situations.

    Science.gov (United States)

    Nijs, Lau; Saher, Konca; den Ouden, Daniël

    2008-02-01

    People increase their vocal output in noisy environments. This is known as the Lombard effect. The aim of the present study was to measure the effect as a function of the absorption coefficient. The noise source was generated by using other talkers in the room. A-weighted sound levels were measured in a 108 m(3) test room. The number of talkers varied from one to four and the absorption coefficients from 0.12 to 0.64. A model was introduced based on the logarithmic sum of the level found in an anechoic room plus the increasing portion of noise levels up to 80 dB. Results show that the model fits the measurements when a maximum slope of 0.5 dB per 1.0 dB increase in background level is used. Hence Lombard slopes vary from 0.2 dBdB at 50 dB background level to 0.5 dBdB at 80 dB. In addition, both measurements and the model predict a decrease of 5.5 dB per doubling of absorbing area in a room when the number of talkers is constant. Sound pressure levels increase for a doubling of talkers from 3 dB for low densities to 6 dB for dense crowds. Finally, there was correspondence between the model estimation and previous measurements reported in the literature.

  14. Absorption of 3(2H)-furanones by human intestinal epithelial Caco-2 cells.

    Science.gov (United States)

    Stadler, Nicole Christina; Somoza, Veronika; Schwab, Wilfried

    2009-05-13

    A number of 3(2H)-furanones are synthesized by fruits and have been found in cooked foodstuffs, where they impart flavor and odor because of their low perception thresholds. They show genotoxic properties in model studies but are also ranked among the antioxidants and anticarcinogens. This study examined the efficiency of intestinal absorption and metabolic conversion of 3(2H)-furanones by using Caco-2 cell monolayers as an intestinal epithelial cell model. The permeability of each agent was measured in both the apical to basal and basal to apical directions. 2,5-Dimethyl-4-methoxy-3(2H)-furanone (DMMF) showed the highest absorption rate in all experiments, while similar amounts of 4-hydroxy-2,5-dimethyl-3(2H)-furanone (HDMF), 4-hydroxy-2(or 5)-ethyl-5(or 2)-methyl-3(2H)-furanone (HEMF), and 4-hydroxy-5-methyl-3(2H)-furanone (HMF) were taken up. HDMF-glucoside was almost not absorbed but was hydrolyzed to a small extent. The transport of 3(2H)-furanones could not be saturated even at levels of 500 microM and occurred in both directions. Because the uptake was only slightly reduced by apical hyperosmolarity, passive diffusion by paracellular transport is proposed.

  15. Absorption of thiamine and nicotinic acid in the rat intestine during fasting and immobilization stress

    Science.gov (United States)

    Kirilyuk, O. G.; Khmelevskiy, Y. V.

    1980-01-01

    By perfusion of isolated sections of intestine with a solution containing thiamine at a concentration of 3.1 micromole, it was established that thiamine absorption in animals fasted for 72 hours decreased by 28 percent, whereas absorption increased by 12 percent in rats after 24 hour immobilization. After immobilization, absorption of label in the intestinal mucosa increased. Na K ATPase activity in the intestinal mucosa decreased by 10 percent during fasting, and it increased with immobilization of the animals. Activity of Na K ATPase in the intestinal mucosa cells determined the absorption rate of thiamine and nicotinic acid at the level of vitamin transport through the plasma membranes of the enterocytes.

  16. Determination of cobalt in human biological liquids from electrothermal atomic absorption spectrometry

    Science.gov (United States)

    Dragan, Felicia; Hîncu, Lucian; Bratu, Ioan

    2009-08-01

    Problems and possibilities of the determination of Co in serum and urine samples by electrothermal atomic absorption spectrometry (ETAAS) are described. Optimal instrumental parameters as well as a suitable atomizer, calibration procedure and hydrogen peroxide as modifier are proposed for direct ETAAS measurement of Co in serum and urine. The detection limit achieved was 0.1 μg L-1 for both matrices and relative standard deviations varied in the range 5-20% depending on the Co concentration in the sample. The validity of the method was verified by the analyses of standard reference materials. For serum samples with Co content lower than the detection limit, a separation and preconcentration procedure based on liquid/liquid extraction is suggested prior to determination of Co in the organic phase by ETAAS. This procedure permits determination of 0.02 μg L-1 Co in serum samples with a relative standard deviation of 10-18%.

  17. Comparison of the absorption, excretion, and metabolism of suxibuzone and phenylbutazone in humans.

    Science.gov (United States)

    Yasuda, Y; Shindo, T; Mitani, N; Ishida, N; Oono, F; Kageyama, T

    1982-05-01

    The absorption, excretion, and metabolism of a single oral dose of suxibuzone, a new nonsteroidal anti-inflammatory agent, in healthy male volunteers were compared with those of phenylbutazone. After oral administration of either suxibuzone or phenylbutazone, phenylbutazone, oxyphenbutazone, and gamma-hydroxyphenylbutazone were found in the plasma; phenylbutazone was the main metabolite of suxibuzone and phenylbutazone. In the urine, p-gamma-dihydroxyphenylbutazone and several glucuronide conjugates also were found. Spectrometric and/or enzymatic analysis showed that these glucuronide conjugates were suxibuzone glucuronide, 4-hydroxymethylphenylbutazone glucuronide, 4-hydroxymethyloxyphenbutazone glucuronide, oxyphenbutazone glucuronide, and phenylbutazone glucuronides (two types: O-glucuronide and C-4-glucuroxide) after suxibuzone administration, and oxyphenbutazone glucuronide and phenylbutazone glucuronide after phenylbutazone administration. The conjugates specific to suxibuzone administration, suxibuzone glucuronide, 4-hydroxymethylphenylbutazone glucuronide, and 4-hydroxymethyloxyphenbutazone glucuronide, were excreted in the first 6 hr urine. These findings and the pharmacokinetics of these metabolites in the plasma and urine show that suxibuzone is a prodrug of phenylbutazone.

  18. Design of miniaturized double-negative material for specific absorption rate reduction in human head.

    Directory of Open Access Journals (Sweden)

    Mohammad Rashed Iqbal Faruque

    Full Text Available In this study, a double-negative triangular metamaterial (TMM structure, which exhibits a resounding electric response at microwave frequency, was developed by etching two concentric triangular rings of conducting materials. A finite-difference time-domain method in conjunction with the lossy-Drude model was used in this study. Simulations were performed using the CST Microwave Studio. The specific absorption rate (SAR reduction technique is discussed, and the effects of the position of attachment, the distance, and the size of the metamaterials on the SAR reduction are explored. The performance of the double-negative TMMs in cellular phones was also measured in the cheek and the tilted positions using the COMOSAR system. The TMMs achieved a 52.28% reduction for the 10 g SAR. These results provide a guideline to determine the triangular design of metamaterials with the maximum SAR reducing effect for a mobile phone.

  19. In vitro study of soil arsenic release by human gut microbiota and its intestinal absorption by Caco-2 cells.

    Science.gov (United States)

    Yin, Naiyi; Cai, Xiaolin; Du, Huili; Zhang, Zhennan; Li, Zejiao; Chen, Xiaochen; Sun, Guoxin; Cui, Yanshan

    2017-02-01

    Arsenic (As) speciation is essential in assessing health risks from As-contaminated soil. Release of soil-bound arsenic, As transformation by human gut microbiota, and the subsequent intestinal absorption of soil As metabolites were evaluated. A colon microbial community in a dynamic human gut model and the intestinal epithelial cell line Caco-2 were cultured. Arsenic speciation analysis and absorption of different As species were undertaken. In this study, soil As release (3.7-581.2 mg kg-1) was observed in the colon. Arsenic in the colon digests was transformed more quickly than that in the soil solid phase. X-ray absorption near-edge spectroscopy (XANES) analysis showed that 44.2-97.6% of arsenite [As(III)] generated due to arsenate [As(V)] reduction was in the soil solid phase after the colon phase. We observed a high degree of cellular absorption of soil As metabolites, exhibiting that the intestinal absorption of monomethylarsonic acid and As(III) (33.6% and 30.2% resp.) was slightly higher than that of dimethylarsinic acid and As(V) (25.1% and 21.7% resp.). Our findings demonstrate that human gut microbiota can directly release soil-bound arsenic, particularly As-bearing amorphous Fe/Al-oxides. Determining As transformation and intestinal absorption simultaneously will result in an accurate risk assessment of human health with soil As exposures. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Probing endocytosis from the enterocyte brush border using fluorescent lipophilic dyes

    DEFF Research Database (Denmark)

    Danielsen, E Michael

    2015-01-01

    The small intestinal brush border is a specialized cell membrane that needs to withstand the solubilizing effect of bile salts during assimilation of dietary nutrients and to achieve detergent resistance; it is highly enriched in glycolipids organized in lipid raft microdomains. In the present work......-toluenesulfonate), and CellMask Orange plasma membrane stain were used to study endocytosis from the enterocyte brush border of organ-cultured porcine mucosal explants. All the dyes readily incorporated into the brush border but were not detectably endocytosed by 5 min, indicating a slow uptake compared with other cell types...

  1. Influence of hydrocolloidal silver nanoparticles on gastrointestinal microflora and morphology of enterocytes of quails

    DEFF Research Database (Denmark)

    Sawosz, Ewa; Binek, Marian; Grodzik, Marta

    2007-01-01

    The objective of the present study was to examine the effects of hydrocolloidal silver nanoparticles (Ag-nano) on microbial profile of caecum and morphology of enterocytes in duodenum of Japanese quail, as a model animal for poultry. Quails (Coturnix coturnix japonica) (10 d old) were randomly...... killed and samples of duodenum and caeca microflora were collected. This initial investigation demonstrated that silver nanoparticles did not influence emphatically microflora of quail caecum; however, water containing 25 mg/kg of Ag-nano significantly increased the population of lactic acid bacteria...

  2. Effect of oil films on moisture vapor absorption on human hair.

    Science.gov (United States)

    Keis, K; Huemmer, C L; Kamath, Y K

    2007-01-01

    In this paper sorption and desorption of water vapor on hair fibers treated with various oils is investigated, using a dynamic vapor sorption (DVS) apparatus. Results show lower "equilibrium" sorption of moisture for various oil-treated samples compared to the untreated sample. Coconut oil-treated hair had a higher regain than mineral oil-treated hair. Although treating the hair samples with oil reduced moisture pickup, a considerable amount of moisture vapor was still able to penetrate into hair fibers. Calculated hysteresis plots show that the samples treated with different oils have slightly higher moisture retention at low relative humidities compared to that of the untreated sample, which suggests a beneficial effect. The calculated moisture diffusion coefficients for oil-treated samples were much lower compared to the untreated hair fibers, suggesting that surface oil films and penetrated oil molecules form a diffusion barrier. A moisture diffusion model is discussed in terms of the possible role of fiber swelling on restrictive narrowing of the cell membrane complexes (CMCs), which form the diffusion pathways in the fiber. The effect of film thickness on moisture absorption and the reverting of the sorption isotherm to that of the untreated hair after removal of the oil film shows that oil film is the main resistance to moisture diffusion. The lowering of the diffusion coefficient of water vapor by oil films will slow the loss of moisture, an effect similar to "moisturization" of hair.

  3. Evaluation of the percutaneous absorption of chlorpromazine from PLO gels across porcine ear and human abdominal skin.

    Science.gov (United States)

    Alsaab, Hashem; Alzhrani, Rami M; Boddu, Sai H S

    2016-08-01

    The overall objective of this work is to determine the percutaneous absorption of chlorpromazine hydrochloride from pluronic lecithin organogels (PLO gels) and verify the suitability of topically applied chlorpromazine hydrochloride PLO gels for use in hospice patients for relieving symptoms such as vomiting and nausea during the end stages of life. PLO gels of chlorpromazine hydrochloride were prepared using isopropyl palmitate (IPP) or ricinoleic acid (RA) as oil phase. In vitro percutaneous absorption of chlorpromazine hydrochloride was assessed through porcine ear and human abdominal skin. Further, the theoretical steady state plasma concentration (Css) of chlorpromazine was calculated from the flux values. The pH, viscosity, and stability of both PLO gels prepared with IPP and RA were comparable. The thixotropic property of RA PLO gel was found to be better than that of IPP PLO gel. The permeation of chlorpromazine hydrochloride was higher from RA PLO gel than from IPP PLO gel and pure drug solution. Theoretical Css of chlorpromazine from pure drug solution, IPP PLO gel and RA PLO gel were found to be 1.05, 1.20, and 1.50 ng/ml, respectively. PLO gels only marginally increased the flux and theoretical Css of chlorpromazine. From this study, it is clearly evident that PLO gels fail to achieve required systemic levels of chlorpromazine following topical application. Chlorpromazine PLO gel may not be effective in treating nausea and vomiting for hospice patients with swallowing difficulties.

  4. Altered gene expression in highly purified enterocytes from patients with active coeliac disease

    Directory of Open Access Journals (Sweden)

    Jackson John

    2008-08-01

    Full Text Available Abstract Background Coeliac disease is a multifactorial inflammatory disorder of the intestine caused by ingestion of gluten in genetically susceptible individuals. Genes within the HLA-DQ locus are considered to contribute some 40% of the genetic influence on this disease. However, information on other disease causing genes is sparse. Since enterocytes are considered to play a central role in coeliac pathology, the aim of this study was to examine gene expression in a highly purified isolate of these cells taken from patients with active disease. Epithelial cells were isolated from duodenal biopsies taken from five coeliac patients with active disease and five non-coeliac control subjects. Contaminating T cells were removed by magnetic sorting. The gene expression profile of the cells was examined using microarray analysis. Validation of significantly altered genes was performed by real-time RT-PCR and immunohistochemistry. Results Enterocyte suspensions of high purity (98–99% were isolated from intestinal biopsies. Of the 3,800 genes investigated, 102 genes were found to have significantly altered expression between coeliac disease patients and controls (p Conclusion This study provides a profile of the molecular changes that occur in the intestinal epithelium of coeliac patients with active disease. Novel candidate genes were revealed which highlight the contribution of the epithelial cell to the pathogenesis of coeliac disease.

  5. Fish oil feeding is associated with an increased accumulation of dietary lipids in enterocytes: Results from an in vivo study in rats

    DEFF Research Database (Denmark)

    Larsen, L.F.; Marckmann, P.; Hansen, A.K.

    2003-01-01

    contents of enterocytes were determined by liquid scintillation counting. Two other groups of rats (2 x 6) fed the experimental diets were given an oral fat load and fasting and postprandial blood samples were taken. Results: The accumulation of H-3-lipids in enterocytes was higher in rats fed fish oil...

  6. Absorption and excretion of black currant anthocyanins in human and Watanabe Heritable Hyperlipidemic rabbits

    DEFF Research Database (Denmark)

    Nielsen, I. L.. F.; Ravn-Haren, Gitte; Dragsted, L. O.

    2003-01-01

    Anthocyanins are thought to protect against cardiovascular diseases. Watanabe heritable hyperlipidemic (WHHL) rabbits are hypercholesterolemic and used as a model of the development of atherosclerosis. To compare the uptake and excretion of anthocyanins in humans and WHHL rabbits, single-dose bla...... as Trolox equivalent antioxidant capacity and ferruc reducing ability of plasma....

  7. Human and mouse tissue-engineered small intestine both demonstrate digestive and absorptive function

    Science.gov (United States)

    Grant, Christa N.; Mojica, Salvador Garcia; Sala, Frederic G.; Hill, J. Ryan; Levin, Daniel E.; Speer, Allison L.; Barthel, Erik R.; Shimada, Hiroyuki; Zachos, Nicholas C.

    2015-01-01

    Short bowel syndrome (SBS) is a devastating condition in which insufficient small intestinal surface area results in malnutrition and dependence on intravenous parenteral nutrition. There is an increasing incidence of SBS, particularly in premature babies and newborns with congenital intestinal anomalies. Tissue-engineered small intestine (TESI) offers a therapeutic alternative to the current standard treatment, intestinal transplantation, and has the potential to solve its biggest challenges, namely donor shortage and life-long immunosuppression. We have previously demonstrated that TESI can be generated from mouse and human small intestine and histologically replicates key components of native intestine. We hypothesized that TESI also recapitulates native small intestine function. Organoid units were generated from mouse or human donor intestine and implanted into genetically identical or immunodeficient host mice. After 4 wk, TESI was harvested and either fixed and paraffin embedded or immediately subjected to assays to illustrate function. We demonstrated that both mouse and human tissue-engineered small intestine grew into an appropriately polarized sphere of intact epithelium facing a lumen, contiguous with supporting mesenchyme, muscle, and stem/progenitor cells. The epithelium demonstrated major ultrastructural components, including tight junctions and microvilli, transporters, and functional brush-border and digestive enzymes. This study demonstrates that tissue-engineered small intestine possesses a well-differentiated epithelium with intact ion transporters/channels, functional brush-border enzymes, and similar ultrastructural components to native tissue, including progenitor cells, whether derived from mouse or human cells. PMID:25573173

  8. Absorption and excretion of mercury in man. XI. Mercury content of normal human tissues

    Energy Technology Data Exchange (ETDEWEB)

    Joselow, M.M.; Goldwater, L.J.; Weinberg, S.B.

    1967-07-01

    Mercury analyses were performed on 236 samples of tissues removed at autopsy from 39 normal human subjects. The samples represented 12 different tissues or organs. The highest values were found in the kidneys. Age did not appear to be a factor in the mercury levels. 14 references, 2 tables.

  9. Digestion and absorption of an egg white ACE-inhibitory peptide in human intestinal Caco-2 cell monolayers.

    Science.gov (United States)

    Ding, Long; Wang, Liying; Yu, Zhipeng; Zhang, Ting; Liu, Jingbo

    2016-01-01

    The objective of this study was to investigate the digestion and absorption of egg white-derived angiotensin I-converting enzyme (ACE)-inhibitory peptide TNGIIR in human intestinal Caco-2 cell monolayers. Results showed that the digestion of TNGIIR to simulated gastrointestinal enzymes and brush border membrane peptidases were 5.87% ± 1.92% and 17.17% ± 0.64%, respectively (p Caco-2 cell monolayers was determined to be (4.92 ± 0.40) × 10(-6) cm/s, indicating that TNGIIR can transport across Caco-2 cell monolayers in intact form. In addition, only cytochalasin D, a disruptor of tight junctions (TJs), changed TNGIIR transport rate significantly (p Caco-2 cell monolayers was paracellular pathway via TJs.

  10. Good oral absorption prediction on non-nucleoside benzothiadiazine dioxide human cytomegalovirus inhibitors using combined chromatographic and neuronal network techniques.

    Science.gov (United States)

    Gil, Carmen; Dorronsoro, Isabel; Castro, Ana; Martinez, Ana

    2005-04-01

    The current drugs available against human cytomegalovirus (HCMV) suffer from a number of shortcomings such as toxic side effect, poor bioavailability and/or risk for emergence of drug-resistance virus strains. Due to these limitations, the development of new drugs against HCMV is of great interest. Taking into account the therapeutic potential of benzothiadiazines dioxides (BTD) derivatives, it is most important to know their oral bioavailability because all the current clinical drugs are poorly absorbed. In this work, the utility of CODES neural networks and biopartitioning micellar chromatography (BMC) in predicting pharmacokinetic properties has been used to estimate the oral absorption of BTD derivatives and their efficacy has been verified. The results indicate higher values for BTD derivatives than the currently licensed anti-viral agents.

  11. Human vitamin B12 absorption measurement by accelerator mass spectrometry using specifically labeled (14)C-cobalamin.

    Science.gov (United States)

    Carkeet, Colleen; Dueker, Stephen R; Lango, Jozsef; Buchholz, Bruce A; Miller, Joshua W; Green, Ralph; Hammock, Bruce D; Roth, John R; Anderson, Peter J

    2006-04-11

    There is a need for an improved test of human ability to assimilate dietary vitamin B(12). Assaying and understanding absorption and uptake of B(12) is important because defects can lead to hematological and neurological complications. Accelerator mass spectrometry is uniquely suited for assessing absorption and kinetics of carbon-14 ((14)C)-labeled substances after oral ingestion because it is more sensitive than decay counting and can measure levels of (14)C in microliter volumes of biological samples with negligible exposure of subjects to radioactivity. The test we describe employs amounts of B(12) in the range of normal dietary intake. The B(12) used was quantitatively labeled with (14)C at one particular atom of the dimethylbenzimidazole (DMB) moiety by exploiting idiosyncrasies of Salmonella metabolism. To grow aerobically on ethanolamine, Salmonella enterica must be provided with either preformed B(12) or two of its precursors, cobinamide and DMB. When provided with (14)C-DMB specifically labeled in the C2 position, cells produced (14)C-B(12) of high specific activity (2.1 GBq/mmol, 58 mCi/mmol) (1 Ci = 37 GBq) and no detectable dilution of label from endogenous DMB synthesis. In a human kinetic study, a physiological dose (1.5 microg, 2.2 kBq/59 nCi) of purified (14)C-B(12) was administered and showed plasma appearance and clearance curves consistent with the predicted behavior of the pure vitamin. This method opens new avenues for study of B(12) assimilation.

  12. Human vitamin B12 absorption measurement by accelerator mass spectrometry using specifically labeled 14C-cobalamin

    Science.gov (United States)

    Carkeet, Colleen; Dueker, Stephen R.; Lango, Jozsef; Buchholz, Bruce A.; Miller, Joshua W.; Green, Ralph; Hammock, Bruce D.; Roth, John R.; Anderson, Peter J.

    2006-01-01

    There is a need for an improved test of human ability to assimilate dietary vitamin B12. Assaying and understanding absorption and uptake of B12 is important because defects can lead to hematological and neurological complications. Accelerator mass spectrometry is uniquely suited for assessing absorption and kinetics of carbon-14 (14C)-labeled substances after oral ingestion because it is more sensitive than decay counting and can measure levels of 14C in microliter volumes of biological samples with negligible exposure of subjects to radioactivity. The test we describe employs amounts of B12 in the range of normal dietary intake. The B12 used was quantitatively labeled with 14C at one particular atom of the dimethylbenzimidazole (DMB) moiety by exploiting idiosyncrasies of Salmonella metabolism. To grow aerobically on ethanolamine, Salmonella enterica must be provided with either preformed B12 or two of its precursors, cobinamide and DMB. When provided with 14C-DMB specifically labeled in the C2 position, cells produced 14C-B12 of high specific activity (2.1 GBq/mmol, 58 mCi/mmol) (1 Ci = 37 GBq) and no detectable dilution of label from endogenous DMB synthesis. In a human kinetic study, a physiological dose (1.5 μg, 2.2 kBq/59 nCi) of purified 14C-B12 was administered and showed plasma appearance and clearance curves consistent with the predicted behavior of the pure vitamin. This method opens new avenues for study of B12 assimilation. PMID:16585531

  13. Human Vitamin B12 Absorption and Metabolism are Measured by Accelerator Mass Spectrometry Using Specifically Labeled 14C-Cobalamin

    Energy Technology Data Exchange (ETDEWEB)

    Carkeet, C; Dueker, S R; Lango, J; Buchholz, B A; Miller, J W; Green, R; Hammock, B D; Roth, J R; Anderson, P J

    2006-01-26

    There is need for an improved test of human ability to assimilate dietary vitamin B{sub 12}. Assaying and understanding absorption and uptake of B{sub 12} is important because defects can lead to hematological and neurological complications. Accelerator mass spectrometry (AMS) is uniquely suited for assessing absorption and kinetics of {sup 14}C-labeled substances after oral ingestion because it is more sensitive than decay counting and can measure levels of carbon-14 ({sup 14}C) in microliter volumes of biological samples, with negligible exposure of subjects to radioactivity. The test we describe employs amounts of B{sub 12} in the range of normal dietary intake. The B{sub 12} used was quantitatively labeled with {sup 14}C at one particular atom of the DMB moiety by exploiting idiosyncrasies of Salmonellametabolism. In order to grow aerobically on ethanolamine, S. entericamust be provided with either pre-formed B{sub 12} or two of its precursors: cobinamide and dimethylbenzimidazole (DMB). When provided with {sup 14}C-DMB specifically labeled in the C2 position, cells produced {sup 14}C-B{sub 12} of high specific activity (2.1 GBq/mmol, 58 mCi/mmol) and no detectable dilution of label from endogenous DMB synthesis. In a human kinetic study, a physiological dose (1.5 mg, 2.2 KBq/59 nCi) of purified {sup 14}C-B{sub 12} was administered and showed plasma appearance and clearance curves consistent with the predicted behavior of the pure vitamin. This method opens new avenues for study of B{sub 12} assimilation.

  14. Impaired gut lipid absorptive capacity after trauma-hemorrhage and resuscitation.

    Science.gov (United States)

    Kerner, J; Wang, P; Chaudry, I H

    1995-10-01

    Although the barrier function of the intestinal mucosa is impaired after hemorrhage, it remains unclear whether this is associated with a deficit in mucosal function. The aim of this study, therefore, was to determine whether trauma-hemorrhage affects the in vivo lipid absorptive capacity of the gut and, if so, to characterize the uptake process of free fatty acids in isolated enterocytes. To study this, rats were anesthetized, a laparotomy was performed (i.e., trauma was induced), and various blood vessels were cannulated. For in vivo lipid absorption, the main intestinal lymph vessel was cannulated and a jejunostomy feeding tube was inserted. The animals were bled to and maintained at a mean arterial pressure of 40 mmHg until 40% of shed blood volume was returned in the form of Ringer lactate. They were then resuscitated with four times the volume of maximal bleed out with Ringer lactate. The in vivo and in vitro lipid absorptive capacities were assessed by measuring lymph triglyceride output after a fat load and by determining the linoleic acid uptake rates on isolated enterocytes, respectively. The results show that the in vivo lipid absorption capacity of the gut is severely depressed after trauma-hemorrhage and resuscitation. Similarly, in enterocytes isolated from hemorrhaged rats, fatty acid uptake capacity, as reflected by the decreased maximal uptake rates, was significantly reduced: 1.2 +/- 0.2 and 2.6 +/- 0.6 nmol.min-1 x 10(6) cells-1 for hemorrhaged and sham, respectively. Thus gut lipid absorptive function is depressed after trauma-hemorrhage and resuscitation, which is at least partially due to the depressed uptake mechanism of the enterocyte.

  15. Expression, Distribution and Role of Aquaporin Water Channels in Human and Animal Stomach and Intestines

    Directory of Open Access Journals (Sweden)

    Cui Zhu

    2016-08-01

    Full Text Available Stomach and intestines are involved in the secretion of gastrointestinal fluids and the absorption of nutrients and fluids, which ensure normal gut functions. Aquaporin water channels (AQPs represent a major transcellular route for water transport in the gastrointestinal tract. Until now, at least 11 AQPs (AQP1–11 have been found to be present in the stomach, small and large intestines. These AQPs are distributed in different cell types in the stomach and intestines, including gastric epithelial cells, gastric glands cells, absorptive epithelial cells (enterocytes, goblet cells and Paneth cells. AQP1 is abundantly distributed in the endothelial cells of the gastrointestinal tract. AQP3 and AQP4 are mainly distributed in the basolateral membrane of epithelial cells in the stomach and intestines. AQP7, AQP8, AQP10 and AQP11 are distributed in the apical of enterocytes in the small and large intestines. Although AQP-null mice displayed almost no phenotypes in gastrointestinal tracts, the alterations of the expression and localization of these AQPs have been shown to be associated with the pathology of gastrointestinal disorders, which suggests that AQPs play important roles serving as potential therapeutic targets. Therefore, this review provides an overview of the expression, localization and distribution of AQPs in the stomach, small and large intestine of human and animals. Furthermore, this review emphasizes the potential roles of AQPs in the physiology and pathophysiology of stomach and intestines.

  16. Expression, Distribution and Role of Aquaporin Water Channels in Human and Animal Stomach and Intestines.

    Science.gov (United States)

    Zhu, Cui; Chen, Zhuang; Jiang, Zongyong

    2016-08-29

    Stomach and intestines are involved in the secretion of gastrointestinal fluids and the absorption of nutrients and fluids, which ensure normal gut functions. Aquaporin water channels (AQPs) represent a major transcellular route for water transport in the gastrointestinal tract. Until now, at least 11 AQPs (AQP1-11) have been found to be present in the stomach, small and large intestines. These AQPs are distributed in different cell types in the stomach and intestines, including gastric epithelial cells, gastric glands cells, absorptive epithelial cells (enterocytes), goblet cells and Paneth cells. AQP1 is abundantly distributed in the endothelial cells of the gastrointestinal tract. AQP3 and AQP4 are mainly distributed in the basolateral membrane of epithelial cells in the stomach and intestines. AQP7, AQP8, AQP10 and AQP11 are distributed in the apical of enterocytes in the small and large intestines. Although AQP-null mice displayed almost no phenotypes in gastrointestinal tracts, the alterations of the expression and localization of these AQPs have been shown to be associated with the pathology of gastrointestinal disorders, which suggests that AQPs play important roles serving as potential therapeutic targets. Therefore, this review provides an overview of the expression, localization and distribution of AQPs in the stomach, small and large intestine of human and animals. Furthermore, this review emphasizes the potential roles of AQPs in the physiology and pathophysiology of stomach and intestines.

  17. Nimodipine nanocrystals for oral bioavailability improvement: role of mesenteric lymph transport in the oral absorption.

    Science.gov (United States)

    Fu, Qiang; Sun, Jin; Ai, Xiaoyu; Zhang, Peng; Li, Mo; Wang, Yongjun; Liu, Xiaohong; Sun, Yinghua; Sui, Xiaofan; Sun, Le; Han, Xiaopeng; Zhu, Meng; Zhang, Yuyang; Wang, Siling; He, Zhonggui

    2013-05-01

    We had conducted a comprehensive study on preparation, characterization and pharmacokinetics of nimodipine nanocrystals for oral administration previously, and nimodipine nanocrystals displayed lower dissolution profiles but higher bioavailability than Nimotop(®). In this study, we aimed at elucidating the reasons of unfavorable in vitro in vivo correlation for NMD nanocrystals and Nimotop(®) with a hypothesis that special oral absorption mechanism was involved in the absorption of nimodipine nanocrystals. Investigations of oral absorption mechanism of the nanocrystals were performed on everted gut sac models, lymphatically (mesenteric lymph duct) cannulated SD rats, Caco-2 cell monolayers and chylomicron flow blocking rats, respectively. The permeability of nanocrystals in duodenum, ileum and colon was not superior to that of Nimotop(®), suggestive of special absorption mechanisms involved. Exudates of nanocrystals from enterocytes were detected in mesenteric lymphatic fluids using a transmission electron microscope, and the bioavailability was only about half of the control after the mesenteric lymph was blocked. The nanocrystals were taken up by enterocytes via macropinocytosis and caveolin-mediated endocytosis pathways. It was impossible to establish a favorable in vitro in vivo correlation for NMD nanocrystals and Nimotop(®), because portions of the nanocrystals underwent macropinocytosis and caveolin-mediated endocytosis by enterocytes as intact nanocrystal forms, then bypassed the liver first-pass metabolism. Copyright © 2013 Elsevier B.V. All rights reserved.

  18. In-vitro percutaneous absorption of losartan potassium in human skin and prediction of human skin permeability

    Directory of Open Access Journals (Sweden)

    Petkar K.C.

    2007-05-01

    Full Text Available This study describes the feasibility of transdermal controlled administration of Losartan potassium (LP across human cadaver skin. Study also defines the influence of capsaicin, sex and site of application on permeation characteristics and determined an appropriate animal model for human skin permeability. The permeation of LP of various formulations was studied using Keshary-Chein diffusion cell. Optimized controlled formulation (without capsaicin released 42.17% (±1.85 of LP in 12 hr whereas treatment formulation (with capsaicin 0.028 % w/v released 48.94% (±1.71 of LP with significant difference on null hypothesis. Influence of sex showed statistically significant difference for permeation of LP through male and female rats, as well as male and female mice across both the abdominal and dorsal sides of the skin (p<0.05. Similarly statistically significant differences were noted for permeation of LP across male and female mice abdomen-dorsal, but not for male rat abdomen-dorsal and female rat abdomen-dorsal. Furthermore, in-vitro permeation of LP across human skin was compared with the permeation across rat and mice skins. Male rat and male mice dorsal skin was found to have closer permeability characteristics to human than other skin membranes, but the Factor of Difference values were < 3 for all membranes which were used suggesting the membranes are good models for human skin permeability. In conclusion simple transdermal adhesive patches formulations incorporating high molecular weight of LP can deliver a dose in-vivo and proposed model skin membranes can be utilized for future pharmacokineic and toxicokinetic studies as well as metabolism studies of LP

  19. An investigation on the effects of organizational memory and human capital on innovation and absorptive capacity

    Directory of Open Access Journals (Sweden)

    Zahra Mansouri

    2014-06-01

    Full Text Available Innovation is considered as an enabling tool for creating value and sustainable competitive advantage for organizations in dynamic environment of our times along with its ever-increasing complexities. Until innovation in developing countries needs more capital and talent, human capital (HC is a key factor in innovative performance. People are the most important factor of exploitation of foreign knowledge; and knowledge focus in business environment is highly dependent on external information sources in order to develop innovation and improve performance of the company. Studies have shown that although importance level of knowledge is increased, but only 30 percent of existing knowledge is being used in organizations. Expensive but evitable mistakes take place due to information blockage; and the risk of losing knowledge is exceptionally higher when people leave the organization. This study is among the field research. The population includes large manufacturing firms across Khuzestan Province having been active throughout 2013. The data collection tool was a structured questionnaire and sampling is convenience method. The research questionnaire was distributed among a sample of 331 R&D and Human resources Experts selected using simple random sampling. The collected data were analyzed using SPSS and Amos statistical programs. The results indicate that organizational memory had significant impact on ACAP and innovation. Results also showed a significant positive effect of HC on ACAP, but did not support the effect of HC on innovation.

  20. in vitro and in silico determination of oral, jejunum and Caco-2 human absorption of fatty acids and polyphenols. Micellar liquid chromatography.

    Science.gov (United States)

    Stępnik, Katarzyna E; Malinowska, Irena; Rój, Edward

    2014-12-01

    In this investigation chosen saturated, mono- and polyunsaturated fatty acids as well as polyphenols have been analyzed. The main aim of this study was to determine oral, jejunum and Caco-2 human absorption of chosen fatty acids and polyphenols using in vitro and in silico methods. For in vitro determination of human drug absorption, the usefulness of Micellar Liquid Chromatography (MLC) with mobile phases containing different surfactants (including Brij35-Biopartitioning Micellar Chromatography (BMC)) has been confirmed. On the basis of Foley's equation, 1/k vs. CM correlations for the tested compounds have been done. Satisfactory linearity of the relationships was found over the whole eluents composition range studied with R(2) approximately 0.99 in each case. Moreover, the analyte-micelle association constants (Kma) from Foley's equation have been compared for different micellar environments, containing Brij35, SDS and CTAB as a main component of micellar mobile phases. Completely new models describing human oral as well as Caco-2 and jejunum absorption have been constructed and compared with the cited models. These models are based on the Abraham descriptors and lipophilicity parameters as well as steric descriptors. Furthermore, many different correlations between physicochemical parameters and human intestinal absorption have been done, e.g. the correlation between human jejunum permeability estimated in silico and received using LSER parameters was excellent (R(2) nearly 0.99). Chromatographic parameters have been collated with steric, electronic and physicochemical ones using QRAR (Quantitative Retention - Activity Relationships) and QSAR (Quantitative Structure - Activity Relationships) models. Moreover, retention BMC data have been compared with lipophilicity parameter logPo/w (n-octanol-water partition coefficient). The influence of lipophilicity on oral absorption (%) has been checked. The correlation between predicted oral absorption (%) and log

  1. Enhanced transferrin receptor expression by proinflammatory cytokines in enterocytes as a means for local delivery of drugs to inflamed gut mucosa.

    Directory of Open Access Journals (Sweden)

    Efrat Harel

    Full Text Available Therapeutic intervention in inflammatory bowel diseases (IBDs is often associated with adverse effects related to drug distribution into non-diseased tissues, a situation which attracts a rational design of a targeted treatment confined to the inflamed mucosa. Upon activation of immune cells, transferrin receptor (TfR expression increases at their surface. Because TfR is expressed in all cell types we hypothesized that its cell surface levels are regulated also in enterocytes. We, therefore, compared TfR expression in healthy and inflamed human colonic mucosa, as well as healthy and inflamed colonic mucosa of the DNBS-induced rat model. TfR expression was elevated in the colonic mucosa of IBD patients in both the basolateral and apical membranes of the enterocytes. Increased TfR expression was also observed in colonocytes of the induced colitis rats. To explore the underlying mechanism CaCo-2 cells were treated with various proinflammatory cytokines, which increased both TfR expression and transferrin cellular uptake in a mechanism that did not involve hyper proliferation. These findings were then exploited for the design of targetable carrier towards inflamed regions of the colon. Anti-TfR antibodies were conjugated to nano-liposomes. As expected, iron-starved Caco-2 cells internalized anti-TfR immunoliposomes better than controls. Ex vivo binding studies to inflamed mucosa showed that the anti-TfR immunoliposomes accumulated significantly better in the mucosa of DNBS-induced rats than the accumulation of non-specific immunoliposomes. It is concluded that targeting mucosal inflammation can be accomplished by nano-liposomes decorated with anti-TfR due to inflammation-dependent, apical, elevated expression of the receptor.

  2. The absorption and uptake of recombinant human follicle-stimulating hormone through vaginal subcutaneous injections - a pharmacokinetic study

    Science.gov (United States)

    Hsu, Chao-Chin; Kuo, Hsin-Chih; Hsu, Chao-Tien; Gu, Qing

    2009-01-01

    Background Follicle stimulating hormone (FSH) has been routinely used for ovulation induction. Because of rapid clearance of the hormone, FSH is commonly administered by daily intramuscular or subcutaneous injections in in-vitro fertilization (IVF). To reduce the number of visits to the clinic, an intermittent vaginal injection of rhFSH every 3 days employing the concepts of mesotherapy and uterine first-pass effect was invented and has successfully been applied in women receiving IVF treatment. This study was designed to monitor the pharmacokinetic pattern of rhFSH administered vaginally. Methods Twelve healthy women with regular ovulatory cycles were recruited. All volunteers received gonadotrophin-releasing hormone agonist to suppress pituitary function and were assigned to receive single dose recombinant human FSH (rhFSH, Puregon 300) either using conventional abdominal subcutaneous injection or vaginal subcutaneous injection in a randomized cross-over study. Serum samples were collected at pre- scheduled time intervals after injections of rhFSH to determine immunoreactive FSH levels. Pharmacokinetic parameters characterizing rate [maximal plasma concentrations (Cmax) and time of maximal plasma concentrations (tmax)] and extent [area under the plasma concentration-time curve (AUC) and clearance] of absorption of rhFSH were compared. Results Vaginal injection of rhFSH was well tolerated and no drug-related adverse reaction was noted. Our analysis revealed that tmax was significantly earlier (mean 6.67 versus 13.33 hours) and Cmax was significantly higher (mean 17.77 versus 13.96 IU/L) in vaginal versus abdominal injections. The AUC0-∞ was 1640 versus 1134 IU·hour/L in vaginal and abdominal injections, respectively. Smaller plasma elimination rate constant (0.011 versus 0.016 hour-1), longer mean residence time (106.58 versus 70.47 hours), and slower total body clearance (292.2 versus 400.1 mL/hour) were also found in vaginal injection. Conclusion The vaginal

  3. The absorption and uptake of recombinant human follicle-stimulating hormone through vaginal subcutaneous injections - a pharmacokinetic study

    Directory of Open Access Journals (Sweden)

    Kuo Hsin-Chih

    2009-10-01

    Full Text Available Abstract Background Follicle stimulating hormone (FSH has been routinely used for ovulation induction. Because of rapid clearance of the hormone, FSH is commonly administered by daily intramuscular or subcutaneous injections in in-vitro fertilization (IVF. To reduce the number of visits to the clinic, an intermittent vaginal injection of rhFSH every 3 days employing the concepts of mesotherapy and uterine first-pass effect was invented and has successfully been applied in women receiving IVF treatment. This study was designed to monitor the pharmacokinetic pattern of rhFSH administered vaginally. Methods Twelve healthy women with regular ovulatory cycles were recruited. All volunteers received gonadotrophin-releasing hormone agonist to suppress pituitary function and were assigned to receive single dose recombinant human FSH (rhFSH, Puregon 300 either using conventional abdominal subcutaneous injection or vaginal subcutaneous injection in a randomized cross-over study. Serum samples were collected at pre- scheduled time intervals after injections of rhFSH to determine immunoreactive FSH levels. Pharmacokinetic parameters characterizing rate [maximal plasma concentrations (Cmax and time of maximal plasma concentrations (tmax] and extent [area under the plasma concentration-time curve (AUC and clearance] of absorption of rhFSH were compared. Results Vaginal injection of rhFSH was well tolerated and no drug-related adverse reaction was noted. Our analysis revealed that tmax was significantly earlier (mean 6.67 versus 13.33 hours and Cmax was significantly higher (mean 17.77 versus 13.96 IU/L in vaginal versus abdominal injections. The AUC0-∞ was 1640 versus 1134 IU·hour/L in vaginal and abdominal injections, respectively. Smaller plasma elimination rate constant (0.011 versus 0.016 hour-1, longer mean residence time (106.58 versus 70.47 hours, and slower total body clearance (292.2 versus 400.1 mL/hour were also found in vaginal injection

  4. [Physiology of intestinal absorption of phosphorus in animals].

    Science.gov (United States)

    Barlet, J P; Davicco, M J; Coxam, V

    1995-01-01

    Intestinal absorption of inorganic phosphorus. In most mammalian species inorganic phosphorus (P) is absorbed at the duodenal and jejunal level. However in horses some P is absorbed from the large intestine, whereas in ruminant animals some absorption also takes place in the forestomachs. The structure of the putative phosphate-sodium carrier of the brush border from enterocytes still awaits identification. P absorption is modulated both by endocrine (calcitriol, triiodothyronine) and nutritional factors (minerals of the diet, chemical form of phosphorus). Regulation of salivary P secretion, intestinal absorption of P in ruminants, and its adaptation to diets high or low in P are still poorly understood. Such studies would probably help to decrease the cost of P supplementation in farm animals.

  5. Determination of ultra-trace aluminum in human albumin by cloud point extraction and graphite furnace atomic absorption spectrometry.

    Science.gov (United States)

    Sun, Mei; Wu, Qianghua

    2010-04-15

    A cloud point extraction (CPE) method for the preconcentration of ultra-trace aluminum in human albumin prior to its determination by graphite furnace atomic absorption spectrometry (GFAAS) had been developed in this paper. The CPE method was based on the complex of Al(III) with 1-(2-pyridylazo)-2-naphthol (PAN) and Triton X-114 was used as non-ionic surfactant. The main factors affecting cloud point extraction efficiency, such as pH of solution, concentration and kind of complexing agent, concentration of non-ionic surfactant, equilibration temperature and time, were investigated in detail. An enrichment factor of 34.8 was obtained for the preconcentration of Al(III) with 10 mL solution. Under the optimal conditions, the detection limit of Al(III) was 0.06 ng mL(-1). The relative standard deviation (n=7) of sample was 3.6%, values of recovery of aluminum were changed from 92.3% to 94.7% for three samples. This method is simple, accurate, sensitive and can be applied to the determination of ultra-trace aluminum in human albumin. 2009 Elsevier B.V. All rights reserved.

  6. Nitrogen and Phosphorus Harvesting from Human Urine Using a Stripping, Absorption, and Precipitation Process.

    Science.gov (United States)

    Pradhan, Surendra K; Mikola, Anna; Vahala, Riku

    2017-05-02

    Human urine contains significant amounts of N (nitrogen) and P (phosphorus); therefore it has been successfully used as fertilizer in different crops. But the use of urine as fertilizer has several constraints, such as, the high cost of transportation, an unpleasant smell, the risk of pathogens, and pharmaceutical residue. A combined and improved N stripping and P precipitation technique is used in this study. In this technique, Ca(OH)2 is used to increase the pH of urine which converts ammonium into ammonia gas and precipitate P as Ca-P compound. The ammonia gas is stripped and passed into the sulfuric acid where ammonium sulfate and hydrogen triammonium disulfate is formed. The experiment was performed using 700 mL of urine and the pH of the urine was increased above 12. Our results showed that 85-99% of N and 99% of P (w/w) can be harvested from urine in 28 h at 40 °C and in 32 h at 30 °C. The harvested N (13% N w/w) and P (1.5% P w/w) can be used as mineral fertilizer. The economic assessment of the technique showed that the extraction of N and P from 1 m3 of pure urine can make a profit of €2.25.

  7. Determination of vanadium in human hair slurries by electrothermal atomic absorption spectrometry.

    Science.gov (United States)

    Fernandes, Kelly G; Nogueira, Ana Rita A; Neto, José A Gomes; Nóbrega, Joaquim A

    2007-02-28

    This work describes an analytical procedure for vanadium determination in human hair slurries by electrothermal AAS using longitudinal heating (LHGA) and transversal heating (THGA) graphite furnace atomizers. The samples were powdered using cryogenic grinding and the hair slurries containing 0.2% (m/v) were prepared in three different media for determination of vanadium: 0.14molL(-1) HNO(3), 0.1% (v/v) Triton X-100 and 0.1% (v/v) water soluble tertiary amines (CFA-C, pH 8). The limits of detection (LOD), limits of quantification (LOQ), and characteristic masses obtained were 0.28, 0.95mugL(-1) and 35pg (LHGA) and 0.34, 1.13mugL(-1) and 78pg (THGA), respectively. The accuracy of the analytical results obtained by the proposed procedure in both equipments was confirmed by a paired t-test at the 95% confidence level and compared with a conventional procedure based on acid digestion.

  8. The enterocyte as an energy flow sensor in the control of eating.

    Science.gov (United States)

    Langhans, Wolfgang

    2010-01-01

    Fuel monitoring in the liver or hepatic portal area was historically implicated in the control of eating. According to this view, a common denominator of nutrient metabolism such as the intracellular ATP/ADP ratio was supposed to modulate eating through changes in hepatic vagal afferent signaling. More recently, this hypothesis has been questioned because hepatic parenchymal vagal afferent innervation is scarce and because experimentally induced changes in hepatic fatty acid oxidation often failed to produce changes in eating. Accumulating evidence suggests that small intestinal enterocytes rather than hepatocytes may serve as energy flow sensors in the control of eating. These recent developments are discussed here and an outline is given of the challenges of this promising new concept. Copyright (c) 2010 S. Karger AG, Basel.

  9. N-acetylcysteine stimulates protein synthesis in enterocytes independently of glutathione synthesis.

    Science.gov (United States)

    Yi, Dan; Hou, Yongqing; Wang, Lei; Long, Minhui; Hu, Shengdi; Mei, Huimin; Yan, Liqiong; Hu, Chien-An Andy; Wu, Guoyao

    2016-02-01

    Dietary supplementation with N-acetylcysteine (NAC) has been reported to improve intestinal health and treat gastrointestinal diseases. However, the underlying mechanisms are not fully understood. According to previous reports, NAC was thought to exert its effect through glutathione synthesis. This study tested the hypothesis that NAC enhances enterocyte growth and protein synthesis independently of cellular glutathione synthesis. Intestinal porcine epithelial cells were cultured for 3 days in Dulbecco's modified Eagle medium containing 0 or 100 μM NAC. To determine a possible role for GSH (the reduced form of glutathione) in mediating the effect of NAC on cell growth and protein synthesis, additional experiments were conducted using culture medium containing 100 μM GSH, 100 μM GSH ethyl ester (GSHee), diethylmaleate (a GSH-depletion agent; 10 μM), or a GSH-synthesis inhibitor (buthionine sulfoximine, BSO; 20 μM). NAC increased cell proliferation, GSH concentration, and protein synthesis, while inhibiting proteolysis. GSHee enhanced cell proliferation and GSH concentration without affecting protein synthesis but inhibited proteolysis. Conversely, BSO or diethylmaleate reduced cell proliferation and GSH concentration without affecting protein synthesis, while promoting protein degradation. At the signaling level, NAC augmented the protein abundance of total mTOR, phosphorylated mTOR, and phosphorylated 70S6 kinase as well as mRNA levels for mTOR and p70S6 kinase in IPEC-1 cells. Collectively, these results indicate that NAC upregulates expression of mTOR signaling proteins to stimulate protein synthesis in enterocytes independently of GSH generation. Our findings provide a hitherto unrecognized biochemical mechanism for beneficial effects of NAC in intestinal cells.

  10. Hemodynamic measurements in rat brain and human muscle using diffuse near-infrared absorption and correlation spectroscopies

    Science.gov (United States)

    Yu, Guoqiang; Durduran, Turgut; Furuya, D.; Lech, G.; Zhou, Chao; Chance, Britten; Greenberg, J. H.; Yodh, Arjun G.

    2003-07-01

    Measurement of concentration, oxygenation, and flow characteristics of blood cells can reveal information about tissue metabolism and functional heterogeneity. An improved multifunctional hybrid system has been built on the basis of our previous hybrid instrument that combines two near-infrared diffuse optical techniques to simultaneously monitor the changes of blood flow, total hemoglobin concentration (THC) and blood oxygen saturation (StO2). Diffuse correlation spectroscopy (DCS) monitors blood flow (BF) by measuring the optical phase shifts caused by moving blood cells, while diffuse photon density wave spectroscopy (DPDW) measures tissue absorption and scattering. Higher spatial resolution, higher data acquisition rate and higher dynamic range of the improved system allow us to monitor rapid hemodynamic changes in rat brain and human muscles. We have designed two probes with different source-detector pairs and different separations for the two types of experiments. A unique non-contact probe mounted on the back of a camera, which allows continuous measurements without altering the blood flow, was employed to in vivo monitor the metabolic responses in rat brain during KCl induced cortical spreading depression (CSD). A contact probe was used to measure changes of blood flow and oxygenation in human muscle during and after cuff occlusion or exercise, where the non-contact probe is not appropriate for monitoring the moving target. The experimental results indicate that our multifunctional hybrid system is capable of in vivo and non-invasive monitoring of the hemodynamic changes in different tissues (smaller tissues in rat brain, larger tissues in human muscle) under different conditions (static versus moving). The time series images of flow during CSD obtained by our technique revealed spatial and temporal hemodynamic changes in rat brain. Two to three fold longer recovery times of flow and oxygenation after cuff occlusion or exercise from calf flexors in a

  11. Absorption of the Wolffian duct and duplicated ureter by the urogenital sinus: morphological study using human fetuses and embryos.

    Science.gov (United States)

    Naito, Michiko; Hinata, Nobuyuki; Rodriguez-Vazquez, Jose Francisco; Murakami, Gen; Aizawa, Shin; Fujisawa, Masato

    2015-07-01

    To describe the embryological origin of the duplicated ureter and to investigate whether the urogenital sinus absorbs not only the Wolffian duct (WD) but also the ureter. During studies using sections of human fetuses (45 specimens), we incidentally found a specific type of ureteric duplication (at ~7 weeks) in which two unilateral ureters joined at the vesico-ureteric junction, apparently representing a morphology arising at an intermediate stage between complete and partial ureteric duplication. The existing literature lacks any photographic representation of early development of the vesico-ureteric junction, and we therefore studied horizontal sections of 10 human embryos (at ~5-6 weeks' gestation) in which the ureter did not join the urogenital sinus (future bladder) but instead joined the WD (future vas deferens). The sinus consistently showed a reversed Y-shape, the arms of which extended posteriorly to receive the WD. When absorption of the duct into the sinus wall reached the distal end of the ureter, the arm-like parts appeared to enlarge posteriorly for further involvement of the duct, with little or no incorporation of the ureter; therefore, the future trigone of the bladder might develop from these arm-like parts of the sinus posterior wall. Consequently, in the case of ureteric duplication included in the present study, it is considered that the ureters would probably have merged with the WD at closely adjacent sites. The present study represents the first photographic illustration of the early development of the human vesico-ureteric junction. © 2014 The Authors BJU International © 2014 BJU International Published by John Wiley & Sons Ltd.

  12. Inhibition of intestinal cholesterol absorption with ezetimibe increases components of reverse cholesterol transport in humans.

    Science.gov (United States)

    Davidson, Michael H; Voogt, Jason; Luchoomun, Jayraz; Decaris, Julie; Killion, Salena; Boban, Drina; Glass, Alexander; Mohammad, Hussein; Lu, Yun; Villegas, Deona; Neese, Richard; Hellerstein, Marc; Neff, David; Musliner, Thomas; Tomassini, Joanne E; Turner, Scott

    2013-10-01

    Reverse cholesterol transport (RCT) can be defined as a pathway of flux of cholesterol from peripheral tissues to the liver for potential excretion into feces. This prospective, placebo-controlled, double-blind crossover study assessed the effect of ezetimibe on several RCT parameters in hyperlipidemic patients. Following 7 weeks of treatment (ezetimibe 10 mg/day or placebo), 26 patients received 24-h continuous IV infusions of [3,4-(13)C2]-cholesterol, then took heavy water ((2)H2O) by mouth. Cholesterol excretion was measured by quantification of neutral/acid sterols in stool and blood samples during 7 days post-infusion with continued treatment. Plasma de novo cholesterol synthesis was assessed by (2)H-labeling from (2)H2O. Ezetimibe significantly reduced levels of low-density lipoprotein cholesterol (22%, P < 0.001) without significant changes in triglycerides and high-density lipoprotein cholesterol and significantly increased the flux of plasma-derived cholesterol into fecal neutral sterols by 52% (P = 0.04) without change in flux into fecal bile acids. Total fecal neutral sterol output increased by 23% (P = 0.02). Plasma de novo cholesterol synthesis increased by 57% (P < 0.001). The fractional clearance rate (FCR) of plasma cholesteryl-ester trended higher (7%; P = 0.055) with a reduction in absolute cholesteryl-ester production rate (9%, P < 0.01). Whole-body free cholesterol efflux rate from extra-hepatic tissues into plasma was not measurably changed by ezetimibe. Ezetimibe treatment approximately doubled the flux of plasma-derived cholesterol into fecal neutral sterols, in association with increases in total fecal neutral sterol excretion, FCR of plasma cholesterol ester, and plasma de novo cholesterol synthesis. These effects are consistent with increased cholesterol transport through the plasma compartment and excretion from the body, in response to ezetimibe treatment in hyperlipidemic humans. Clintrials.gov: NCT00701727. Copyright

  13. Effects of posture on FDTD calculations of specific absorption rate in a voxel model of the human body

    Energy Technology Data Exchange (ETDEWEB)

    Findlay, R P; Dimbylow, P J [National Radiological Protection Board, Chilton, Didcot, Oxon OX11 0RQ (United Kingdom)

    2005-08-21

    A change in the posture of the human body can significantly affect the way in which it absorbs radiofrequency electromagnetic radiation. To study this, an anatomically realistic model of the body has been modified to develop new voxel models in postures other than the standard standing position with arms to the side. These postures were sitting, arms stretched out horizontally to the side and vertically above the head. Finite-difference time-domain (FDTD) calculations of the whole-body averaged specific energy absorption rate (SAR) have been performed from 10 MHz to 300 MHz at a resolution of 4 mm. Calculations show that the effect of a raised arm above the head posture was to increase the value of the whole-body averaged SAR at resonance by up to 35% when compared to the standard, arms by the side position. SAR values, both whole-body averaged and localized in the ankle, were used to derive the external electric field values required to produce the SAR basic restrictions of the ICNIRP guidelines. It was found that, in certain postures, external electric field reference levels alone would not provide a conservative estimate of localized SAR exposure and it would be necessary to invoke secondary reference levels on limb currents to provide compliance with restrictions.

  14. Evaluation of the Electromagnetic Power Absorption in Humans Exposed to Plane Waves: The Effect of Breathing Activity

    Directory of Open Access Journals (Sweden)

    Marta Cavagnaro

    2013-01-01

    Full Text Available The safety aspects of the exposure of people to uniform plane waves in the frequency range from 900 MHz to 5 GHz are analyzed. Starting from a human body model available in the literature, representing a man in resting state, two new anatomical models are considered, representing different phases of the respiratory activity: tidal breath and deep breath. These models have been used to evaluate the whole body Specific Absorption Rate (SAR and the 10-g averaged and 1-g averaged SAR. The analysis is performed using a parallel implementation of the finite difference time domain method. A uniform plane wave, with vertical polarization, is used as an incident field since this is the canonical exposure situation used in safety guidelines. Results show that if the incident electromagnetic field is compliant with the reference levels promulgated by the International Commission on Non-Ionizing Radiation Protection and by IEEE, the computed SAR values are lower than the corresponding basic restrictions, as expected. On the other side, when the Federal Communications Commission reference levels are considered, 1-g SAR values exceeding the basic restrictions for exposure at 4 GHz and above are obtained. Furthermore, results show that the whole body SAR values increase passing from the resting state model to the deep breath model, for all the considered frequencies.

  15. Average absorption cross-section of the human body measured at 1-12 GHz in a reverberant chamber: results of a human volunteer study.

    Science.gov (United States)

    Flintoft, I D; Robinson, M P; Melia, G C R; Marvin, A C; Dawson, J F

    2014-07-07

    The electromagnetic absorption cross-section (ACS) averaged over polarization and angle-of-incidence of 60 ungrounded adult subjects was measured at microwave frequencies of 1-12 GHz in a reverberation chamber. Average ACS is important in non-ionizing dosimetry and exposure studies, and is closely related to the whole-body averaged specific absorption rate (WBSAR). The average ACS was measured with a statistical uncertainty of less than 3% and high frequency resolution for individuals with a range of body shapes and sizes allowing the statistical distribution of WBSAR over a real population with individual internal and external morphologies to be determined. The average ACS of all subjects was found to vary from 0.15 to 0.4 m(2); for an individual subject it falls with frequency over 1-6 GHz, and then rises slowly over the 6-12 GHz range in which few other studies have been conducted. Average ACS and WBSAR are then used as a surrogate for worst-case ACS/WBSAR, in order to study their variability across a real population compared to literature results from simulations using numerical phantoms with a limited range of anatomies. Correlations with body morphological parameters such as height, mass and waist circumference have been investigated: the strongest correlation is with body surface area (BSA) at all frequencies above 1 GHz, however direct proportionality to BSA is not established until above 5 GHz. When the average ACS is normalized to the BSA, the resulting absorption efficiency shows a negative correlation with the estimated thickness of subcutaneous body fat. Surrogate models and statistical analysis of the measurement data are presented and compared to similar models from the literature. The overall dispersion of measured average WBSAR of the sample of the UK population studied is consistent with the dispersion of simulated worst-case WBSAR across multiple numerical phantom families. The statistical results obtained allow the calibration of human

  16. Restricted access carbon nanotubes for direct extraction of cadmium from human serum samples followed by atomic absorption spectrometry analysis.

    Science.gov (United States)

    Barbosa, Adriano F; Barbosa, Valéria M P; Bettini, Jefferson; Luccas, Pedro O; Figueiredo, Eduardo C

    2015-01-01

    In this paper, we propose a new sorbent that is able to extract metal ions directly from untreated biological fluids, simultaneously excluding all proteins from these samples. The sorbent was obtained through the modification of carbon nanotubes (CNTs) with an external bovine serum albumin (BSA) layer, resulting in restricted access carbon nanotubes (RACNTs). The BSA layer was fixed through the interconnection between the amine groups of the BSA using glutaraldehyde as cross-linker. When a protein sample is percolated through a cartridge containing RACNTs and the sample pH is higher than the isoelectric point of the proteins, both proteins from the sample and the BSA layer are negatively ionized. Thus, an electrostatic repulsion prevents the interaction between the proteins from the sample on the RACNTs surface. At the same time, metal ions are adsorbed in the CNTs (core) after their passage through the chains of proteins. The Cd(2+) ion was selected for a proof-of-principle case to test the suitability of the RACNTs due to its toxicological relevance. RACNTs were able to extract Cd(2+) and exclude almost 100% of the proteins from the human serum samples in an online solid-phase extraction system coupled with thermospray flame furnace atomic absorption spectrometry. The limits of detection and quantification were 0.24 and 0.80 μg L(-1), respectively. The sampling frequency was 8.6h(-1), and the intra- and inter-day precisions at the 0.80, 15.0, and 30.0 μg L(-1) Cd(2+) levels were all lower than 10.1% (RSD). The recoveries obtained for human blood serum samples fortified with Cd(2+) ranged from 85.0% to 112.0%. The method was successfully applied to analyze Cd(2+) directly from six human blood serum samples without any pretreatment, and the observed concentrations ranged from

  17. Sulfated Cholecystokinin-8 Promotes CD36—Mediated Fatty Acid Uptake into Primary Mouse Duodenal Enterocytes

    Directory of Open Access Journals (Sweden)

    Claire Demenis

    2017-09-01

    Full Text Available Cholecystokinin (CCK is an archetypal incretin hormone secreted by intestinal enteroendocrine cells (EEC in response to ingested nutrients. The aim of this study was to determine whether CCK modulates enterocyte fatty acid uptake by primary mouse duodenal cells. Exposure of primary mouse duodenal cells to 10 pM sulfated CCK-8 caused a two fold increase in dodecanoic acid fatty acid (FA uptake. The selective CCK A receptor antagonist loxiglumide (100 μM completely abolished the CCK-8 induced FA uptake. The CD36 fatty acid translocase-specific inhibitor sulfo-N-succinimidyl oleate (1 μM also completely inhibited CCK-8 induced FA uptake, as did treatment with 200 μM phloretin. Together these data show CCK induces FA uptake into duodenal enterocytes; this action involves the CCK-RA receptor and is carrier mediated by CD36.

  18. Assay for evaluation of rotavirus-cell interactions: identification of an enterocyte ganglioside fraction that mediates group A porcine rotavirus recognition.

    OpenAIRE

    Rolsma, M D; Gelberg, H B; Kuhlenschmidt, M S

    1994-01-01

    A virus-host cell-binding assay was developed and used to investigate specific binding between group A porcine rotavirus and MA-104 cells or porcine enterocytes. A variety of glycoconjugates and cellular components were screened for their ability to block rotavirus binding to cells. During these experiments a crude ganglioside mixture was observed to specifically block rotavirus binding. On the basis of these results, enterocytes were harvested from susceptible piglets and a polar lipid fract...

  19. Enterocyte loss of polarity and gut wound healing rely upon the F-actin–severing function of villin

    Science.gov (United States)

    Ubelmann, Florent; Chamaillard, Mathias; El-Marjou, Fatima; Simon, Anthony; Netter, Jeanne; Vignjevic, Danijela; Nichols, Buford L.; Quezada-Calvillo, Roberto; Grandjean, Teddy; Louvard, Daniel; Revenu, Céline; Robine, Sylvie

    2013-01-01

    Efficient wound healing is required to maintain the integrity of the intestinal epithelial barrier because of its constant exposure to a large variety of environmental stresses. This process implies a partial cell depolarization and the acquisition of a motile phenotype that involves rearrangements of the actin cytoskeleton. Here we address how polarized enterocytes harboring actin-rich apical microvilli undergo extensive cell remodeling to drive injury repair. Using live imaging technologies, we demonstrate that enterocytes in vitro and in vivo rapidly depolarize their microvilli at the wound edge. Through its F-actin–severing activity, the microvillar actin-binding protein villin drives both apical microvilli disassembly in vitro and in vivo and promotes lamellipodial extension. Photoactivation experiments indicate that microvillar actin is mobilized at the lamellipodium, allowing optimal migration. Finally, efficient repair of colonic mechanical injuries requires villin severing of F-actin, emphasizing the importance of villin function in intestinal homeostasis. Thus, villin severs F-actin to ensure microvillus depolarization and enterocyte remodeling upon injury. This work highlights the importance of specialized apical pole disassembly for the repolarization of epithelial cells initiating migration. PMID:23520048

  20. Enterocyte loss of polarity and gut wound healing rely upon the F-actin-severing function of villin.

    Science.gov (United States)

    Ubelmann, Florent; Chamaillard, Mathias; El-Marjou, Fatima; Simon, Anthony; Netter, Jeanne; Vignjevic, Danijela; Nichols, Buford L; Quezada-Calvillo, Roberto; Grandjean, Teddy; Louvard, Daniel; Revenu, Céline; Robine, Sylvie

    2013-04-09

    Efficient wound healing is required to maintain the integrity of the intestinal epithelial barrier because of its constant exposure to a large variety of environmental stresses. This process implies a partial cell depolarization and the acquisition of a motile phenotype that involves rearrangements of the actin cytoskeleton. Here we address how polarized enterocytes harboring actin-rich apical microvilli undergo extensive cell remodeling to drive injury repair. Using live imaging technologies, we demonstrate that enterocytes in vitro and in vivo rapidly depolarize their microvilli at the wound edge. Through its F-actin-severing activity, the microvillar actin-binding protein villin drives both apical microvilli disassembly in vitro and in vivo and promotes lamellipodial extension. Photoactivation experiments indicate that microvillar actin is mobilized at the lamellipodium, allowing optimal migration. Finally, efficient repair of colonic mechanical injuries requires villin severing of F-actin, emphasizing the importance of villin function in intestinal homeostasis. Thus, villin severs F-actin to ensure microvillus depolarization and enterocyte remodeling upon injury. This work highlights the importance of specialized apical pole disassembly for the repolarization of epithelial cells initiating migration.

  1. Green tea extract decreases starch digestion and absorption from a test meal in humans: a randomized, placebo-controlled crossover study.

    Science.gov (United States)

    Lochocka, Klaudia; Bajerska, Joanna; Glapa, Aleksandra; Fidler-Witon, Ewa; Nowak, Jan K; Szczapa, Tomasz; Grebowiec, Philip; Lisowska, Aleksandra; Walkowiak, Jaroslaw

    2015-07-30

    Green tea is known worldwide for its beneficial effects on human health. However, objective data evaluating this influence in humans is scarce. The aim of the study was to assess the impact of green tea extract (GTE) on starch digestion and absorption. The study comprised of 28 healthy volunteers, aged 19 to 28 years. In all subjects, a starch (13)C breath test was performed twice. Subjects randomly ingested naturally (13)C-abundant cornflakes during the GTE test (GTE 4 g) or placebo test. The cumulative percentage dose recovery (CPDR) was significantly lower for the GTE test than for the placebo test (median [interquartile range]: 11.4% [5.5-15.5] vs. 16.1% [12.7-19.5]; p = 0.003). Likewise, CPDR expressed per hour was considerably lower in each point of the measurement. In conclusion, a single dose of green tea extract taken with a test meal decreases starch digestion and absorption.

  2. Bioinformatics analysis of the locus for enterocyte effacement provides novel insights into type-III secretion

    Directory of Open Access Journals (Sweden)

    Bailey Christopher M

    2005-03-01

    Full Text Available Abstract Background Like many other pathogens, enterohaemorrhagic and enteropathogenic strains of Escherichia coli employ a type-III secretion system to translocate bacterial effector proteins into host cells, where they then disrupt a range of cellular functions. This system is encoded by the locus for enterocyte effacement. Many of the genes within this locus have been assigned names and functions through homology with the better characterised Ysc-Yop system from Yersinia spp. However, the functions and homologies of many LEE genes remain obscure. Results We have performed a fresh bioinformatics analysis of the LEE. Using PSI-BLAST we have been able to identify several novel homologies between LEE-encoded and Ysc-Yop-associated proteins: Orf2/YscE, Orf5/YscL, rORF8/EscI, SepQ/YscQ, SepL/YopN-TyeA, CesD2/LcrR. In addition, we highlight homology between EspA and flagellin, and report many new homologues of the chaperone CesT. Conclusion We conclude that the vast majority of LEE-encoded proteins do indeed possess homologues and that homology data can be used in combination with experimental data to make fresh functional predictions.

  3. Lactobacillus strains belonging to Casei group display various adherence to enterocytes and mucus.

    Science.gov (United States)

    Markowicz, Corinna; Schmidt, Marcin T

    2015-01-01

    The ability of lactobacilli to adhere to the surface of the intestine is an important functional characteristic which can largely determine the effective colonization of the intestinal tract by probiotics. The following study compares the adhesion efficiency of the twenty strains of Lactobacillus genus belonging to Casei group to the Caco-2 cells and gastrointestinal mucus. Twenty isolates of lactobacilli belonging to Casei group were tested. The ability of bacterial cells to adhere to mucus was examined using adhesion assay to gastrointestinal mucus. Obtained results were compared with adhesion efficiency to Caco-2 cells. Phylogenetic relationship between isolates was analysed by rep-PCR. The results showed large differences in adhesion efficiency between strains, as well as differences in the efficiency of adhesion to the intestinal epithelial cells and mucus. Group similarity highlighted by a rep-PCR technique does not correspond with groups of similarity in terms of the characteristics of the ability to adhere to mucus or the epithelial cells of intestinal tract. Strains having a high adhesion efficiency to enterocytes do not always show a high adhesion efficiency to the mucus. This may indicate the presence of different and multiple factors responsible for adhesion efficiency of Lactobacillus group Casei strains to epithelial cells and mucus.

  4. [Biotransformation by human intestinal flora and absorption-transportation characteristic in a model of Caco-2 cell monolayer of d-corydaline and tetrahydropalmatine].

    Science.gov (United States)

    Liu, Yang-Zi; Yang, Xin-Bao; Yang, Xiu-Wei; Yao, Chun-Mei; Ran, Li; Wu, Shuai; Xu, Wei; Liu, Jian-Xun

    2013-01-01

    To study the biotransformation by human intestinal flora, and the absorption and transportation characteristic in a model of human colon adenocarcinoma cell lines (Caco-2 cell) monolayer of d-corydaline (CDL) and tetrahydropalmatine (THP). CDL or THP was incubated with crude enzymes of human intestinal flora under the anaerobic environment and 37 degrees C conditions to transform CDL or THP. Caco-2 cell monolayer was used as an intestinal epithelial cell model for determination of the permeability of CDL or THP from apical side (AP side) to basolateral side (BL side) or from BL side to AP side. Transportation parameters and permeability coefficients (P(app)) were then calculated, and P(app) values were compared with the reported values for model compounds, propranolol as a well absorbed drug and atenolol as a poor absorbed drug. The concentration of CDL or THP was measured by HPLC coupled with photodiode array detector. CDL or THP in the human intestinal flora incubation system did not happen biotransformation. In the Caco-2 cell monolayer model, the P(app) magnitudes of both CDL and THP were 1 x 10(-5) cm x s(-1) in the bi-directional transport, which were identical with propranolol. And their transports were concentration dependent between 0-180 min. Both CDL and THP may be stable in the human intestinal flora incubation system, and their absorption and transportation in the human Caco-2 cell monolayer model are mainly via passive diffusion mechanism.

  5. Absorption of 51Cr EDTA across the human nasal airway barriers in the presence of topical histamine.

    Science.gov (United States)

    Greiff, L; Wollmer, P; Pipkorn, U; Persson, C G

    1991-01-01

    Whether histamine, a mediator that causes exudation, affects the airway absorption of luminal solutes has been examined in a study of eight healthy volunteers. Fluid containing the absorption tracer chromium-51 labelled EDTA was instilled into one nasal cavity for 15 minutes, with a nasal pool-device (total volume 14 ml). The airway absorption of 51Cr EDTA determined by urinary recovery of radioactivity corresponded to 0.095 (SE 0.023) ml of the instillate in the absence of histamine. When histamine was added to the nasal instillate at a concentration of 2.0 mg/ml, which is known to produce substantial exudation of plasma into the airway lumen, the absorption of 51Cr EDTA was unchanged (0.093 (0.025) ml of the instillate). Separate experiments excluded the possibility that any swallowed portion of 51Cr EDTA could have contributed significantly to the amount absorbed. The present data agree with previous observations in guinea pig tracheobronchial airways, where histamine and other exudative agents did not increase the mucosal absorption of solutes from the airway lumen. These data suggest that the potent protein systems of blood plasma can transverse the endothelial-epithelial linings and operate on the surface of the airway mucosa without compromising its integrity as a barrier to luminal material. PMID:1948790

  6. Lead and cadmium in human teeth from Jordan by atomic absorption spectrometry: Some factors influencing their concentrations

    Energy Technology Data Exchange (ETDEWEB)

    Alomary, A. [Department of Chemistry, Yarmouk University, Irbid (Jordan)]. E-mail: ahmedalomary1000@hotmail.com; Al-Momani, I.F. [Department of Chemistry, Yarmouk University, Irbid (Jordan); Massadeh, A.M. [Department of Medicinal Chemistry and Pharmacognosy, Faculty of Pharmacy, Jordan University of Science and Technology, Irbid (Jordan)

    2006-10-01

    The aim of this study was to measure the concentrations of lead (Pb) and cadmium (Cd) in human teeth and to investigate the affecting factors. Teeth samples (n = 268) were collected from people living in different cities in Jordan including Amman, Zarqa, Al-Mafraq and Irbid and analyzed for Pb and Cd using atomic absorption spectrometry (AAS). A questionnaire was used to gather information on each person, such as age, sex, place where the patient lives, smoking, presence of amalgam fillings inside the mouth, and whether the patient uses toothpaste or not. The mean concentrations of Pb and Cd were 28.91 {mu}g/g and 0.44 {mu}g/g, respectively. The results indicate that there is a clear relation between Pb and Cd concentrations and the presence of amalgam fillings, smoking, and place of living. Pb was sex-dependent, whereas Cd was not. Our results show that Pb and Cd concentrations in samples obtained from Al-Mafraq and Irbid are higher than those obtained from Amman and Zarqa. Pb was highest in Mafraq, whereas Cd was highest in Irbid. The Pb and Cd concentrations in teeth from smokers (means: Pb = 31.89 {mu}g/g, Cd = 0.49 {mu}g/g) were significantly higher than those from nonsmokers (means: Pb = 24.07 {mu}g/g, Cd = 0.37 {mu}g/g). Pb and Cd concentrations in teeth of patients with amalgam fillings (means: Pb = 31.02 {mu}g/g and Cd = 0.52 {mu}g/g) were significantly higher than those from patients without amalgam fillings (means: Pb = 26.87 {mu}g/g and Cd = 0.41 {mu}g/g). Our results show that brushing the teeth daily with toothpaste does not significantly decrease the concentration of both Pb and Cd. The mean concentrations of Pb and Cd do not vary significantly between the ages 20-30, 31-40, and 41-50, but both increased rapidly at age 51-60.

  7. Modeling gastrointestinal drug absorption requires more in vivo biopharmaceutical data: experience from in vivo dissolution and permeability studies in humans.

    Science.gov (United States)

    Lennernäs, Hans

    2007-10-01

    The majority (84%) of the 50 most-sold pharmaceutical products in the US and European markets are given orally. The dominating role of this route in drug therapy is a consequence of it being safe, efficient and easily accessible with minimal discomfort to the patient in comparison with other routes of drug administration. A successful drug discovery and development of oral pharmaceutical products require an in-depth understanding of multiple biochemical and physiological processes that determine the dissolution rate, intestinal permeability, gastrointestinal transit, first-pass extraction and systemic exposure-time profiles of drugs. It is crucial to realize that these basic biopharmaceutic and pharmacokinetic properties are crucial to focus on to allow successful drug development. Identification of the rate-limiting step(s) in order to overcome these barriers and understanding of the sources of variability are important in the selection of suitable candidate molecules in drug development. Several reports based on in vitro investigations in various cell models have suggested that carrier-mediated intestinal efflux may be a major reason for incomplete absorption and variable bioavailability of drugs, as well being a site for drug-drug and specific food-drug interactions. However, many drugs which were initially suggested to undergo significant efflux in vitro were later shown to be completely absorbed in vivo. This apparent discrepancy between in vitro and in vivo results may be due to several factors that will be discussed in this review. Novel data on solubility and dissolution in human gastrointestinal derived fluids will be reviewed. The effect of food intake on solubility and dissolution rate of a range of drugs including felodipine, danazol, griseofulvin, cyclosporine, probucol and ubiquinone in simulated and real intestinal fluids is discussed. The biopharmaceutic and physicochemical data discussed here can potentially be used as a benchmark set for

  8. Effect of insulin catheter wear-time on subcutaneous adipose tissue blood flow and insulin absorption in humans

    DEFF Research Database (Denmark)

    Clausen, Trine Schnedler; Kaastrup, Peter; Stallknecht, Bente

    2009-01-01

    BACKGROUND: Insertion of an insulin catheter for continuous subcutaneous insulin infusion into the subcutaneous adipose tissue (SAT) causes a tissue trauma that may have consequences for insulin absorption. We evaluated the importance of insulin catheter wear-time on subcutaneous adipose tissue...... blood flow (ATBF) and absorption of the rapid-acting insulin analog insulin aspart over a period of 4 days. METHODS: Teflon insulin catheters (Medtronic, Minneapolis, MN) were inserted into the abdominal SAT of 10 healthy men without diabetes (mean +/- SEM age, 23.0 +/- 1.1 years; body mass index, 22...

  9. Metabolic and drug distribution studies do not support direct inhibitory effects of metformin on intestinal glucose absorption.

    Science.gov (United States)

    Cuber, J C; Bosshard, A; Vidal, H; Vega, F; Wiernsperger, N; Rapin, J R

    1994-01-01

    In an attempt to clarify the question of an involvement of the inhibition of intestinal glucose absorption in the mechanism of action of Metformin, we used several experimental approaches: 1 glucose/lactate measurement in rat portal blood in vivo and 2 in the venous effluent of an isolated perfused rat intestinal segment; 3 metabolism of freshly isolated enterocytes in vitro and tissue distribution of 3H-labeled Metformin was investigated both in vivo and in vitro. Metformin applied intraluminally had no significant effect on portal glycaemia after a glucose load, but lactate increased, whereas in vivo only a high Metformin dosage reduced portal glucose appearance significantly. Although high Metformin concentrations were found in gut biopsies, precise histological analysis in the isolated intestine revealed that it was absent from enterocytes; however the drug accumulated in villous lacteals. Intrarterially applied Metformin decreased glucose absorption in the isolated perfused ileo-jejunal segment. These data suggested that vascular Metformin boosted intestinal anaerobic glucose metabolism. Biochemical measurements performed on freshly isolated enterocytes showed that even high Metformin levels did not interfere with cell respiration or with Na+/K+ ATPase activity. Thus, our data agree with other recent reports, suggesting that even at nontherapeutic concentrations Metformin has no relevant inhibitory effect on intestinal glucose absorption. The data are discussed in the frame of previous divergent observations. The results suggest however that Metformin of vascular origin stimulates glucose consumption by the intestine, which then increases lactate output from the gut.

  10. Quantitative photoacoustic integrating sphere (QPAIS) platform for absorption coefficient and Gruneisen parameter measurements: Demonstration with human blood

    NARCIS (Netherlands)

    Villanueva, Y.Y.; Hondebrink, Erwin; Petersen, Wilhelmina; Steenbergen, Wiendelt

    2017-01-01

    Quantitative photoacoustic imaging in biomedicine relies on accurate measurements of relevant material properties of target absorbers. Here, we present a method for simultaneous measurements of the absorption coefficient and Grüneisen parameter of small volume of liquid scattering and absorbing

  11. Effects of physiological hyperglycemia on duodenal motility and flow events, glucose absorption, and incretin secretion in healthy humans

    NARCIS (Netherlands)

    Kuo, Paul; Wishart, Judith M.; Bellon, Max; Smout, André J.; Holloway, Richard H.; Fraser, Robert J. L.; Horowitz, Michael; Jones, Karen L.; Rayner, Christopher K.

    2010-01-01

    CONTEXT: Acute hyperglycemia slows gastric emptying, but its effects on small intestinal motor activity and glucose absorption are unknown. In type 2 diabetes, the postprandial secretion of glucose-dependent insulinotropic polypeptide (GIP) is preserved, but that of glucagon-like peptide-1 (GLP-1)

  12. Fractional cholesterol absorption measurements in humans : Determinants of the blood-based dual stable isotope tracer technique

    NARCIS (Netherlands)

    Stellaard, Frans; Luetjohann, Dieter

    BACKGROUND: The flux of absorbed cholesterol is a controlling element in the regulation of cholesterol biosynthesis and catabolism. A review of 5 published methods to measure cholesterol absorption is presented, including 2 dual stable isotope approaches. The continuous dual isotope feeding

  13. Intestinal fluid absorption in anadromous salmonids: importance of tight junctions and aquaporins

    Directory of Open Access Journals (Sweden)

    Kristina eSundell

    2012-09-01

    Full Text Available The anadromous salmonid life cycle includes both fresh water (FW and seawater (SW stages. The parr-smolt transformation (smoltification pre–adapt the fish to SW while still in FW. The osmoregulatory organs change their mode of action from a role of preventing water inflow in FW, to absorb ions to replace water lost by osmosis in SW. During smoltification, the drinking rate increases, in the intestine the ion and fluid transport increases and is further elevated after SW entry. In SW, the intestine absorbs ions to create an inwardly directed water flow which is accomplished by increased Na+,K+-ATPase (NKA activity in the basolateral membrane, driving ion absorption via ion channels and/or co-transporters. This review will aim at discussing the expression patterns of the ion transporting proteins involved in intestinal fluid absorption in the FW stage, during smoltification and after SW entry. Of equal importance for intestinal fluid absorption as the active absorption of ions, is the permeability of the epithelium to ions and water. During the smoltification the increase in NKA activity and water uptake in SW is accompanied by decreased paracellular permeability suggesting a redirection of the fluid movement from a paracellular route in FW, to a transcellular route in SW. Increased transcellular fluid absorption could be achieved by incorporation of aquaporins (AQPs into the enterocyte membranes and/or by a change in fatty acid profile of the enterocyte lipid bilayer. An increased incorporation of unsaturated fatty acids into the membrane phospholipids will increase water permeability by enhancing the fluidity of the membrane. A second aim of the present review is therefore to discuss the presence and regulation of expression of AQPs in the enterocyte membrane as well as to discuss the profile of fatty acids present in the membrane phospholipids during different stages of the salmonid lifecycle.

  14. Circular dichroism and absorption spectroscopic data reveal binding of the natural cis-carotenoid bixin to human alpha1-acid glycoprotein.

    Science.gov (United States)

    Zsila, Ferenc; Molnár, Péter; Deli, József; Lockwood, Samuel F

    2005-08-01

    Using circular dichroism (CD) and electronic absorption spectroscopy techniques, interaction of the natural dietary cis-carotenoid bixin with an important human plasma protein in vitro was demonstrated for the first time. The induced CD spectra of bixin obtained under physiological conditions (pH 7.4, 37 degrees C) revealed its binding to the serum acute-phase reactant alpha(1)-acid glycoprotein (AGP), a member of the lipocalin protein family. Spectral features of the extrinsic Cotton effects of bixin suggested the inclusion of a single, chirally distorted ligand molecule into the asymmetric protein environment. Compared with the absorption spectra obtained in ethanol and benzene, the strong red shift of the main absorption peak of AGP-bound bixin indicated that the proposed binding site was rich in aromatic residues, and also suggested that hydrophobic interactions were involved in the binding. Using the data obtained from the CD titration experiments, the association constant (Ka=4.5x10(5)M-1) and stoichiometry of the binding (0.15) were calculated. The low value of the stoichiometry was attributed to the structural polymorphism of AGP. To the authors' knowledge, the current study represents the first human lipocalin protein for which carotenoid binding affinity has been explored in vitro with these techniques.

  15. High-performance liquid chromatography method for the quantification of non-radiolabelled cinnamic compounds in analytes derived from human skin absorption and metabolism experiments.

    Science.gov (United States)

    Smith, C K; Cheung, C; Elahi, E N; Hotchkiss, S A

    2001-07-15

    An isocratic high-performance liquid chromatography method has been developed for the quantification of the skin sensitisers trans-cinnamaldehyde and trans-cinnamic alcohol, and their cinnamic metabolites. The relative standard deviations (RSDs) between the gradients of eight sets of standard curves were 2.8, 3.1 and 1.9% for cinnamic alcohol, cinnamaldehyde and cinnamic acid, respectively. Sample analytes were derived from two series of experiments: in vitro full-thickness human skin absorption and metabolism studies and metabolism studies using human skin homogenates, with non-radiolabelled cinnamic compounds. Skin absorption and metabolism experiments were performed in the absence and presence of the alcohol dehydrogenase inhibitor, pyrazole. Samples from full-thickness skin absorption studies were analysed without extraction; cinnamic compounds from within skin were extracted into methanolic solutions using newly developed methods. The intra-assay RSDs ranged from 0.17 to 2.52% for cinnamic alcohol, 0.24 to 9.14% for cinnamaldehyde and 0.26 to 6.43% for cinnamic acid. The inter-assay RSDs for cinnamic alcohol, cinnamaldehyde and cinnamic acid, respectively, as determined from n=20 HPLC runs, were 2.10, 4.16 and 2.26%.

  16. In vivo investigations of neurotensin receptors in adipocytes, hepatocytes and enterocytes of rat.

    Science.gov (United States)

    Piątek, Jacek; Maćkowiak, Paweł; Krauss, Hanna; Nowak, Dorota; Bogdański, Paweł

    2011-01-01

    Atherosclerotic vascular disease is currently the biggest threat and the highest cause of death worldwide, approaching almost 60%.The development of atherosclerosis is affected by ecological factors associated with industry and pollution of the environment. Neurotensin (NT) is a peptide acting via 3 kinds of neurotensin receptors (NTR) localized in target tissues. In several studies, the presence of its receptors has been shown in chicken liver, and the influence of NT on the metabolism of this organ was confirmed (glycogenolysis stimulation through sympathetic nervous system, enterohepatic circulation of bile acids, metabolism of lipoproteins). Healthy male WISTAR rats weighing 300}30 grams, were used for the experiments. The animals were divided into 4 groups: 1) control group, to which 0.9% NaCl was administrated (i.p.); 2) the second group was given levocabastine 1mg/kg i.p.; 3) the third group received SR 48692 0.4 mg/; 4) the fourth group was given NT analog [D-Trp 11]-neurotensin 15 nM/kg. Plasmatic membranes of liver, small intestine and adipose tissue were prepared according to the method of Havrankova. Analysis of results obtained in the investigation of NT receptors was performed using the Scatchard method from LIGAND-Pc, v. 3.1 software. The investigation of antigenity of I125NT showed proper antigen-antibody reaction. No binding of the I125NT with plasmatic membranes of adipocytes or enterocytes was observed. Unspecific binding of I125NT with 10 μmol/L of free NT was observed in the plasmatic membranes of hepatocytes. The presence of NT receptors only in the membranes of hepatocytes may suggest their role in the regulation of lipid metabolism via receptor – ligand way.

  17. Calcium overload injury of rats' enterocyte IEC-6 by heat stress in vitro

    Directory of Open Access Journals (Sweden)

    Yan GENG

    2013-07-01

    Full Text Available Objective To investigate the effect of gradient heat stress on calcium overload of rats' enterocyte IEC-6 and calcium overload-related cell injury in vitro. Methods Thermal gradient was set in culturing IEC-6 cells in vitro. After thermal stimulation, Fluo-3Am probe with fluorescence microscope or flow cytometry was used to detect the change in intracellular Ca2+ concentration of IEC-6 cells. Phase contrast microscope was used to observe the morphological change in IEC-6. Coomassie blue dying method was employed to test the change in IEC-6 cytoskeleton. CCK-8 assay was used to assess cellular viability. Adhesion assay was applied to test the change in basilar membrane adhesiveness of IEC-6 cells. Results Compared with normal control group, cells of heat stress groups showed a thermal-dependent increase in intracellular Ca2+ concentration (P<0.01. Cells of heat stress groups were rounded in shape, the pseudopod was shorter, and cell space was enlarged. These phenomena were more obvious in 45℃ culture than in that of 43℃. Coomassie blue dying showed that the cytoskeleton of cells in heat stress groups became thickened and disordered, and stress fibers appeared. These phenomena were also more obvious in 45℃ culture than in that of 43℃. A thermal-dependant decline of cell viability in heat stress groups was observed via CCK-8 assay (P<0.01, and a thermal-dependant decline of basilar membrane adhesiveness in heat stress groups was observed via adhesion assay (P<0.01. Conclusion Heat stress may cause calcium overload of IEC-6 cells, and thus resulting in a series of calcium overload-related cell injury. Further investigation of the effect and mechanism of heat stress on calcium overload of intestinal mucosa endothelial cells may help further understand the mechanism of the pathogenesis of heat stroke.

  18. Dietary inulin affects the expression of intestinal enterocyte iron transporters, receptors and storage protein and alters the microbiota in the pig intestine.

    Science.gov (United States)

    Tako, E; Glahn, R P; Welch, R M; Lei, X; Yasuda, K; Miller, D D

    2008-03-01

    Inulin, a linear beta fructan, is present in a variety of plants including chicory root and wheat. It exhibits prebiotic properties and has been shown to enhance mineral absorption and increase beneficial bacteria in the colon. The aim of the present study was to assess the effect of dietary inulin on the gene expression of selected intestinal Fe transporters and binding proteins. Anaemic piglets at age 5 weeks were allocated to a standard maize-soya diet (control) or the same diet supplemented with inulin at a level of 4 %. After 6 weeks, the animals were killed and caecum contents and sections of the duodenum and colon were removed. Segments of the genes encoding for the pig divalent metal transporter 1 (DMT1) and duodenal cytochrome-b reductase (Dcytb) were isolated and sequenced. Semi-quantitative RT-PCR analyses were performed to evaluate the expression of DMT1, Dcytb, ferroportin, ferritin, transferrin receptor (TfR) and mucin genes. DMT1, Dcytb, ferroportin, ferritin and TfR mRNA levels in duodenal samples were significantly higher in the inulin group (P < or = 0.05) compared with the control. In colon, DMT1, TfR and ferritin mRNA levels significantly increased in the inulin group. Additionally, the caecal content microflora was examined using 16S rDNA targeted probes from bacterial DNA. The Lactobacillus and Bifidobacterium populations were significantly increased in the inulin group (P < or = 0.05) compared with the control group. These results indicate that dietary inulin might trigger an up regulation of genes encoding for Fe transporters in the enterocyte. The specific mechanism for this effect remains to be elucidated.

  19. Evaluation of the use of Göttingen minipigs to predict food effects on the oral absorption of drugs in humans

    DEFF Research Database (Denmark)

    Christiansen, Martin Lau; Müllertz, Anette; Garmer, Mats

    2015-01-01

    This study investigated the oral absorption of drugs in minipigs to predict food effects in man. The protocol was based on a previously described model in dogs and further investigated the food source (i.e., US FDA breakfast or a nutritional drink) and food quantities. Two poorly soluble compounds...... in minipigs when compared with humans, within a range from 2.3 to 8.4 h dependent on the food regimen. There were no significant differences in drug absorption between fed and fasted state for the two compounds. The study showed that the dog protocol could not be transferred directly to minipigs, but needs...... were investigated [pravastatin (negative food effect) and atazanavir (positive food effect)] in Göttingen minipigs after seven different food regimens. The gastric emptying rate was evaluated by coadministration of acetaminophen. In short, the results demonstrated longer gastric emptying times...

  20. Evaluation of purine utilization by Lactobacillus gasseri strains with potential to decrease the absorption of food-derived purines in the human intestine.

    Science.gov (United States)

    Yamada, N; Iwamoto, C; Kano, H; Yamaoka, N; Fukuuchi, T; Kaneko, K; Asami, Y

    2016-12-01

    It is well accepted that frequent and heavy intake of purine-rich foods causes elevation of serum uric acid levels, which is a risk factor of hyperuricemia. Reducing intestinal absorption of dietary purines may attenuate the elevation of serum uric acid levels and exacerbation of hyperuricemia. This reduction may be achieved by the ingestion of lactic acid bacteria that take up purines in the intestine. In this study, we investigated the degree of uptake and utilization of purines of three lactobacilli strains. Among them, Lactobacillus gasseri PA-3 (PA-3) showed the greatest incorporation of 14C-adenine. PA-3 also incorporated 14C-adenosine and 14C-AMP. Additionally, using defined growth medium, PA-3 demonstrated greater proliferation in the presence of these purines than in their absence. Although further investigation is required, ingestion of PA-3 may lower serum uric acid levels by reducing intestinal absorption of purines in humans.

  1. Determination of sulfur in human hair using high resolution continuum source graphite furnace molecular absorption spectrometry and its correlation with total protein and albumin

    Science.gov (United States)

    Ozbek, Nil; Baysal, Asli

    2017-04-01

    Human hair is a valuable contributor for biological monitoring. It is an information storage point to assess the effects of environmental, nutritional or occupational sources on the body. Human proteins, amino acids or other compounds are among the key components to find the sources of different effects or disorders in the human body. Sulfur is a significant one of these compounds, and it has great affinity to some metals and compounds. This property of the sulfur affects the human health positively or negatively. In this manuscript, sulfur was determined in hair samples of autistic and age-match control group children via molecular absorption of CS using a high-resolution continuum source graphite furnace atomic absorption spectrometer. For this purpose, hair samples were appropriately washed and dried at 75 °C. Then samples were dissolved in microwave digestion using HNO3 for sulfur determination. Extraction was performed with HCl hydrolysation by incubation for 24 h at 110 °C for total protein and albumin determination. The validity of the method for the sulfur determination was tested using hair standard reference materials. The results were in the uncertainty limits of the certified values at 95% confidence level. Finally correlation of sulfur levels of autistic children's hair with their total protein and albumin levels were done.

  2. Effect of browned and unbrowned corn products intrinsically labeled with 65Zn on absorption of /sup 65/Zn in humans

    Energy Technology Data Exchange (ETDEWEB)

    Lykken, G.I.; Mahalko, J.; Johnson, P.E.; Milne, D.; Sandstead, H.H.; Garcia, W.J.; Dintzis, F.R.; Inglett, G.E.

    1986-05-01

    Experimental browned and unbrowned corn products were formulated and processed from unenriched, degermed yellow corngrits. The browned product (cornflakes) contained more insoluble dietary fiber and bound more zinc (in vitro) than the unbrowned product (corngrits). During processing some of the cornflakes and corngrits were combined with a small amount of yellow corn endospermhull intrinsically labeled with /sup 65/Zn. The intrinsically labeled corn products were fed, in a crossover design, as components of two breakfasts to six normal, unconfined volunteers. Each volunteer absorbed more /sup 65/Zn from the corngrits than from the cornflakes. The reduced /sup 65/Zn absorption from cornflakes was attributed to heating and toasting reaction products, possibly Maillard, which bound zinc and consequently made the zinc less available for absorption.

  3. Masked trichothecene and zearalenone mycotoxins withstand digestion and absorption in the upper GI tract but are efficiently hydrolyzed by human gut microbiota in vitro.

    Science.gov (United States)

    Gratz, Silvia W; Dinesh, Reshma; Yoshinari, Tomoya; Holtrop, Grietje; Richardson, Anthony J; Duncan, Gary; MacDonald, Susan; Lloyd, Antony; Tarbin, Jonathan

    2017-04-01

    Cereal grains are commonly contaminated with Fusarium mycotoxins and their plant-derived masked metabolites. The fate of masked mycotoxins in the human gut is poorly understood. Here we assess the metabolism and transport of glucoside metabolites of common trichothecenes (deoxynivalenol, nivalenol, T-2 toxin) and zearalenone compounds (zearalenone, α- and β-zearalenol) in the human gut in vitro. Masked mycotoxins were incubated with artificial digestive juices and absorption was assessed in differentiated Caco-2/TC7 cells. Colonic metabolism was studied using fecal batch cultures from five donors and mycotoxins were detected using LC-MS/MS. All masked mycotoxins were stable under upper GI tract conditions and no absorption was observed. Free trichothecenes were absorbed intact whereas free zearalenone compounds were absorbed and metabolized to undetected compounds by Caco-2/TC7 cells. Human gut microbiota efficiently hydrolyzed all masked mycotoxins. Trichothecenes were fully recovered as parent mycotoxins whereas 40-70% of zearalenone compounds were further metabolized to unknown metabolites. Our results demonstrate that masked trichothecenes will reach the colon intact to be released as parent mycotoxins by gut microbiota, hence contributing to mycotoxin exposure. Masked zearalenone compounds are metabolized by gut microbiota and epithelial cells and the identity and toxicity of metabolites remain to be determined. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Blanching improves anthocyanin absorption from highbush blueberry ( Vaccinium corymbosum L.) purée in healthy human volunteers: a pilot study.

    Science.gov (United States)

    Del Bo', Cristian; Riso, Patrizia; Brambilla, Ada; Gardana, Claudio; Rizzolo, Anna; Simonetti, Paolo; Bertolo, Gianni; Klimis-Zacas, Dorothy; Porrini, Marisa

    2012-09-12

    Blueberries ( Vaccinium corymbosum L.) are rich sources of phenolics and anthocyanins (ACNs). We investigated the absorption of ACNs after consumption of one portion (300 g) of minimally processed blueberry purée (P) obtained from blanched (BL) or unblanched (NB) berries. A repeated-measures, crossover design study was conducted on healthy human volunteers. Blood was drawn between baseline and 24 h after BL-P or NB-P consumption, while urine were collected from the day before the experiment up to 48 h. Total plasma ACN content was not significantly different, while phenolics content was higher in BL-P with respect to NB-P. The maximum ACN absorption in plasma was observed after 1.5 h from the intake of the purées and was significantly higher (p ≤ 0.05) after the intake of BL-P. Both products increased the excretion of hippuric acid in urine. In conclusion, blanching had no significant effect on total ACN content and enhanced their absorption from minimally processed purées.

  5. Quantity of ethanol absorption after excessive hand disinfection using three commercially available hand rubs is minimal and below toxic levels for humans.

    Science.gov (United States)

    Kramer, Axel; Below, Harald; Bieber, Nora; Kampf, Guenter; Toma, Cyril D; Huebner, Nils-Olaf; Assadian, Ojan

    2007-10-11

    Despite the increasing promotion of alcohol-based hand rubs and the worldwide use of ethanol-based hand rubs in hospitals only few studies have specifically addressed the issue of ethanol absorption when repeatedly applied to human skin. The aim of this study was to assess if ethanol absorption occurs during hygienic and surgical hand disinfection using three different alcohol-based hand-rubs, and to quantify absorption levels in humans. Twelve volunteers applied three hand-rubs containing 95% (hand-rub A), 85% (hand-rub B) and 55% ethanol (hand-rub C; all w/w). For hygienic hand disinfection, 4 mL were applied 20 times for 30 s, with 1 minute break between applications. For surgical hand disinfection, 20 mL of each hand rub was applied to hands and arms up to the level of the elbow 10 times for 3 minutes, with a break of 5 minutes between applications. Blood concentrations of ethanol and acetaldehyde were determined immediately prior and up to 90 minutes after application using head space gas chromatography. The median of absorbed ethanol after hygienic hand disinfection was 1365 mg (A), 630 mg (B), and 358 mg (C). The proportion of absorbed ethanol was 2.3% (A), 1.1% (B), and 0.9% (C). After surgical hand disinfection, the median of absorbed ethanol was 1067 mg (A), 1542 mg (B), and 477 mg (C). The proportion of absorbed ethanol was 0.7% (A), 1.1% (B), and 0.5% (C). The highest median acetaldehyde concentration after 20 hygienic hand disinfections was 0.57 mg/L (hand-rub C, after 30 min), after 10 surgical hand disinfections 3.99 mg/L (hand-rub A, after 20 minutes). The overall dermal and pulmonary absorption of ethanol was below toxic levels in humans and allows the conclusion that the use of the evaluated ethanol-based hand-rubs is safe.

  6. Quantity of ethanol absorption after excessive hand disinfection using three commercially available hand rubs is minimal and below toxic levels for humans

    Directory of Open Access Journals (Sweden)

    Toma Cyril D

    2007-10-01

    Full Text Available Abstract Background Despite the increasing promotion of alcohol-based hand rubs and the worldwide use of ethanol-based hand rubs in hospitals only few studies have specifically addressed the issue of ethanol absorption when repeatedly applied to human skin. The aim of this study was to assess if ethanol absorption occurs during hygienic and surgical hand disinfection using three different alcohol-based hand-rubs, and to quantify absorption levels in humans. Methods Twelve volunteers applied three hand-rubs containing 95% (hand-rub A, 85% (hand-rub B and 55% ethanol (hand-rub C; all w/w. For hygienic hand disinfection, 4 mL were applied 20 times for 30 s, with 1 minute break between applications. For surgical hand disinfection, 20 mL of each hand rub was applied to hands and arms up to the level of the elbow 10 times for 3 minutes, with a break of 5 minutes between applications. Blood concentrations of ethanol and acetaldehyde were determined immediately prior and up to 90 minutes after application using head space gas chromatography. Results The median of absorbed ethanol after hygienic hand disinfection was 1365 mg (A, 630 mg (B, and 358 mg (C. The proportion of absorbed ethanol was 2.3% (A, 1.1% (B, and 0.9% (C. After surgical hand disinfection, the median of absorbed ethanol was 1067 mg (A, 1542 mg (B, and 477 mg (C. The proportion of absorbed ethanol was 0.7% (A, 1.1% (B, and 0.5% (C. The highest median acetaldehyde concentration after 20 hygienic hand disinfections was 0.57 mg/L (hand-rub C, after 30 min, after 10 surgical hand disinfections 3.99 mg/L (hand-rub A, after 20 minutes. Conclusion The overall dermal and pulmonary absorption of ethanol was below toxic levels in humans and allows the conclusion that the use of the evaluated ethanol-based hand-rubs is safe.

  7. Absorption and excretion of mercury in man. VIII. Mercury exposure from house paint - a controlled study on humans

    Energy Technology Data Exchange (ETDEWEB)

    Jacobs, M.B.; Goldwater, L.J.

    1965-10-01

    Experiments were performed to ascertain the degree of mercury exposure and the absorption of mercury that may occur when a paint which contains approximately 0.02% of mercury is used for interior surfaces. Possible effects on the painters who apply the paint and on persons who live in the rooms were studied. Urine samples and blood samples were collected from the individuals who participated in the study. Paints containing a mercury-bearing preservative had a mercury vapor value of 0.17 mg/cu meter in about 90 minutes. It stayed at this concentration level about 2 hrs and then fell to 0.01 mg/cu meter in 24 hrs. The total mercury concentration was 0.20 mg/cu meter for 4 1/2 hrs. After 24 hrs with no exceptional attempts at ventilation the concentration of mercury decreased to an insignificant level. No evidence was found of mercury exposure or absorption in a degree that would constitute a hazard to the individuals involved in the study.

  8. Luminal leptin inhibits intestinal sugar absorption in vivo.

    Science.gov (United States)

    Iñigo, C; Patel, N; Kellett, G L; Barber, A; Lostao, M P

    2007-08-01

    We have previously demonstrated that leptin inhibits galactose absorption in rat intestinal everted rings and that leptin receptors are present in the apical membrane of the enterocytes. This adipocyte-derived hormone is also secreted by gastric mucosal cells and is able to reach the intestinal lumen. The goal of the present study was to prove whether luminal leptin acts on intestinal sugar absorption in vivo both at low (basal state) and high sugar concentration (post-prandial state). In vivo intestinal sugar absorption in rat was measured with recirculating and single-pass perfusion systems. Sugar disappearance in the perfusate was measured by radioactivity and biochemical methods. Luminal leptin effect on intestinal absorption mediated by sodium-dependent glucose transporter 1 (SGLT1) and glucose transporter 2 (GLUT2) as well as intestinal permeability (mannitol absorption) was determined. Luminal leptin inhibited intestinal sugar absorption at low galactose concentrations, which indicates that leptin regulates SGLT1 activity in vivo. The inhibition was reversed in the absence of hormone in the intestinal lumen, suggesting that it was produced by post-translational regulation processes. At high luminal glucose concentrations, leptin also inhibited the phloretin-insensitive component of sugar absorption mediated by SGLT1. There was no significant effect on the apical GLUT2 component of absorption. Leptin did not modify in vivo intestinal permeability determined with (14)C-mannitol. These observations support the view that gastric leptin exerts a regulatory role on intestinal sugar absorption in the postprandial state by modifying the active component of absorption.

  9. Infrared Spectroscopy as a Tool to Study the Antioxidant Activity of Polyphenolic Compounds in Isolated Rat Enterocytes

    Science.gov (United States)

    Barraza-Garza, Guillermo; Castillo-Michel, Hiram; de la Rosa, Laura A.; Martinez-Martinez, Alejandro; Pérez-León, Jorge A.; Cotte, Marine; Alvarez-Parrilla, Emilio

    2016-01-01

    The protective effect of different polyphenols, catechin (Cat), quercetin (Qc) (flavonoids), gallic acid (GA), caffeic acid (CfA), chlorogenic acid (ChA) (phenolic acids), and capsaicin (Cap), against H2O2-induced oxidative stress was evaluated in rat enterocytes using Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR) Spectroscopy and Fourier Transform Infrared Microspectroscopy (FTIRM), and results were compared to standard lipid peroxidation techniques: conjugated dienes (CD) and Thiobarbituric Acid Reactive Substances (TBARS). Analysis of ATR-FTIR and FTIRM spectral data allowed the simultaneous evaluation of the effects of H2O2 and polyphenols on lipid and protein oxidation. All polyphenols showed a protective effect against H2O2-induced oxidative stress in enterocytes, when administered before or after H2O2. Cat and capsaicin showed the highest protective effect, while phenolic acids had weaker effects and Qc presented a mild prooxidative effect (IR spectral profile of biomolecules between control and H2O2-treated cells) according to FTIR analyses. These results demonstrated the viability to use infrared spectroscopy to evaluate the oxidant and antioxidant effect of molecules in cell systems assays. PMID:27213031

  10. Infrared Spectroscopy as a Tool to Study the Antioxidant Activity of Polyphenolic Compounds in Isolated Rat Enterocytes

    Directory of Open Access Journals (Sweden)

    Guillermo Barraza-Garza

    2016-01-01

    Full Text Available The protective effect of different polyphenols, catechin (Cat, quercetin (Qc (flavonoids, gallic acid (GA, caffeic acid (CfA, chlorogenic acid (ChA (phenolic acids, and capsaicin (Cap, against H2O2-induced oxidative stress was evaluated in rat enterocytes using Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR Spectroscopy and Fourier Transform Infrared Microspectroscopy (FTIRM, and results were compared to standard lipid peroxidation techniques: conjugated dienes (CD and Thiobarbituric Acid Reactive Substances (TBARS. Analysis of ATR-FTIR and FTIRM spectral data allowed the simultaneous evaluation of the effects of H2O2 and polyphenols on lipid and protein oxidation. All polyphenols showed a protective effect against H2O2-induced oxidative stress in enterocytes, when administered before or after H2O2. Cat and capsaicin showed the highest protective effect, while phenolic acids had weaker effects and Qc presented a mild prooxidative effect (IR spectral profile of biomolecules between control and H2O2-treated cells according to FTIR analyses. These results demonstrated the viability to use infrared spectroscopy to evaluate the oxidant and antioxidant effect of molecules in cell systems assays.

  11. Database Extraction of Metabolite Information of Drug Candidates: Analysis of 27 AstraZeneca Compounds with Human Absorption, Distribution, Metabolism, and Excretion Data.

    Science.gov (United States)

    Iegre, Jessica; Hayes, Martin A; Thompson, Richard A; Weidolf, Lars; Isin, Emre M

    2016-05-01

    As part of the drug discovery and development process, it is important to understand the human metabolism of a candidate drug prior to clinical studies. Preclinical in vitro and in vivo experiments across species are conducted to build knowledge concerning human circulating metabolites in preparation for clinical studies; therefore, the quality of these experiments is critical. Within AstraZeneca, all metabolite identification (Met-ID) information is stored in a global database using ACDLabs software. In this study, the Met-ID information derived from in vitro and in vivo studies for 27 AstraZeneca drug candidates that underwent human absorption, distribution, metabolism, and excretion studies was extracted from the database. The retrospective analysis showed that 81% of human circulating metabolites were previously observed in preclinical in vitro and/or in vivo experiments. A detailed analysis was carried out to understand which human circulating metabolites were not captured in the preclinical experiments. Metabolites observed in human hepatocytes and rat plasma but not seen in circulation in humans (extraneous metabolites) were also investigated. The majority of human specific circulating metabolites derive from multistep biotransformation reactions that may not be observed in in vitro studies within the limited time frame in which cryopreserved hepatocytes are active. Factors leading to the formation of extraneous metabolites in preclinical studies seemed to be related to species differences with respect to transporter activity, secondary metabolism, and enzyme kinetics. This retrospective analysis assesses the predictive value of Met-ID experiments and improves our ability to discriminate between metabolites expected to circulate in humans and irrelevant metabolites seen in preclinical studies. Copyright © 2016 by The American Society for Pharmacology and Experimental Therapeutics.

  12. Absorption of flavonols derived from sea buckthorn (Hippophaë rhamnoides L.) and their effect on emerging risk factors for cardiovascular disease in humans.

    Science.gov (United States)

    Suomela, Jukka-Pekka; Ahotupa, Markku; Yang, Baoru; Vasankari, Tommi; Kallio, Heikki

    2006-09-20

    Sea buckthorn (Hippophaë rhamnoides L.) is a rich source of flavonols, especially isorhamnetin. Most prospective cohort studies have indicated some degree of inverse association between flavonoid intake and coronary heart disease. Animal and human studies suggest that sea buckthorn flavonoids may scavenge free radicals, lower blood viscosity, and enhance cardiac function. The effects of flavonol aglycones derived from sea buckthorn on the risk factors of cardiovascular disease as well as their absorption were studied in humans. The flavonols, ingested with oatmeal porridge, did not have a significant effect on the levels of oxidized low-density lipoprotein, C-reactive protein, and homocysteine, on the plasma antioxidant potential, or on the paraoxonase activity. Flavonols at two dosages in oatmeal porridge were rapidly absorbed, and a relatively small amount of sea buckthorn oil added to the porridge seemed to have increased the bioavailability of sea buckthorn flavonols consumed at the higher dose.

  13. Effect of triacylglycerol structure on absorption and metabolism of isotope-labeled palmitic and linoleic acids by humans.

    Science.gov (United States)

    Emken, E A; Adlof, R O; Duval, S M; Shane, J M; Walker, P M; Becker, C

    2004-01-01

    The effect of dietary TAG structure and fatty acid acyl TAG position on palmitic and linoleic acid metabolism was investigated in four middle-aged male subjects. The study design consisted of feeding diets containing 61 g/d of native lard (NL) or randomized lard (RL) for 28 d. Subjects then received an oral dose of either 1,3-tetradeuteriopalmitoyl-2-dideuteriolinoleoyl-rac-glycerol or a mixture of 1,3-dideuteriolinoleoyl-2-tetradeuteriopalmitoyl-rac-glycerol and 1,3-hexadeuteriopalmitoyl-2-tetradeuteriolinoleoyl-rac-glycerol. Methyl esters of plasma lipids isolated from blood samples drawn over a 2-d period were analyzed by GC-MS. Results showed that absorption of the 2H-fatty acids (2H-FA) was not influenced by TAG position. The 2H-FA at the 2-acyl TAG position were 85+/-4.6% retained after absorption. Substantial migration of 2H-16:0 (31.2+/-8.6%) from the sn-2 TAG position to the sn-1,3 position and 2H-18:2n-6 (52.8+/-6.4%) from the sn-1,3 position to the sn-2 position of chylomicron TAG occurred after initial absorption and indicates the presence of a previously unrecognized isomerization mechanism. Incorporation and turnover of the 2H-FA in chylomicron TAG, plasma TAG, and plasma cholesterol esters were not influenced by TAG acyl position. Accretion of 2H-16:0 from the sn-2 TAG position in 1-acylphosphatidylcholine was 1.7 times higher than 2H-16:0 from the sn-1,3 TAG positions. Acyl TAG position did not influence 2H-18:2n-6 incorporation in PC. The concentration of 2H-18:2n-6-derived 2H-20:4n-6 in plasma PC from subjects fed the RL diet was 1.5 times higher than for subjects fed the NL diet, and this result suggests that diets containing 16:0 located at the sn-2 TAG position may inhibit 20:4n-6 synthesis. The overall conclusion is that selective rearrangement of chylomicron TAG structures diminishes but does not totally eliminate the metabolic and physiological effects of dietary TAG structure.

  14. Effects of olsalazine and sulphasalazine on jejunal and ileal water and electrolyte absorption in normal human subjects.

    OpenAIRE

    Raimundo, A H; Patil, D H; Frost, P G; Silk, D B

    1991-01-01

    The effect of sulphasalazine and olsalazine on jejunal and ileal water and electrolyte absorption was investigated in normal subjects by a steady state intestinal perfusion of a physiological glucose bicarbonate electrolyte solution in the absence and presence of increasing concentrations of each drug. (Olsalazine 0.25 g/l, 1.0 g/l, jejunum; 0.5 g/l, 1.0 g/l, ileum; sulphasalazine 0.25 g/l, 0.5 g/l, 2.0 g/l jejunum; 1.0 g/l, 2.0 g/l, ileum.) In the jejunum olsalazine at 1.0 g/l significantly ...

  15. Fractional cholesterol absorption measurements in humans: determinants of the blood-based dual stable isotope tracer technique.

    Science.gov (United States)

    Stellaard, Frans; Lütjohann, Dieter

    2015-01-01

    The flux of absorbed cholesterol is a controlling element in the regulation of cholesterol biosynthesis and catabolism. A review of 5 published methods to measure cholesterol absorption is presented, including 2 dual stable isotope approaches. The continuous dual isotope feeding procedure is accurate, but only suitable for small-scale studies. The blood-based dual stable isotope technique is the least invasive and complex procedure, but leads to large variations in individual (90%) and mean population values (24%-70%) for healthy subjects. The results may be partly determined by the experimental and analytical procedures. Fifteen blood-based dual stable isotope studies published between 1993 and 2013 have been analyzed. The results were related to the methodologies applied and evidence was sought for accordance to the test principles. Seven different isotopic tracers, 3 cholesterol subcompartments in blood, and 6 mass spectrometry techniques were applied. The oral and intravenous test formulations were presented in only 1 study. Time points for blood sampling and methodologies for blood sample preparation and analysis were highly variable. No definite proofs were supplied for the fates of the oral and intravenous cholesterol tracers. Isotope enrichment measurements in free and total cholesterol in plasma and erythrocytes were never compared. Fractional cholesterol absorption rate values depend strongly on the mass spectrometry methodology. Dual-inlet isotope ratio mass spectrometry appears to be the method of choice. Dual stable isotope approaches require validation and standardization of administration and analysis procedures. A control group must always be included to correct for methodological differences. Copyright © 2015 National Lipid Association. Published by Elsevier Inc. All rights reserved.

  16. Cinnamon extract regulates intestinal lipid metabolism related gene expression in primary enterocytes of rats

    Science.gov (United States)

    Emerging evidence suggests that the small intestine is not a passive organ, but is actively involved in the regulation of lipid absorption, intracellular transport, and metabolism, and is closely linked to systemic lipoprotein metabolism. We have reported previously that the water-soluble components...

  17. Ambivalent role of gallated catechins in glucose tolerance in humans: a novel insight into non-absorbable gallated catechin-derived inhibitors of glucose absorption.

    Science.gov (United States)

    Park, J H; Jin, J Y; Baek, W K; Park, S H; Sung, H Y; Kim, Y K; Lee, J; Song, D K

    2009-12-01

    Prolonged postprandial hyperglycemia is a detrimental factor for type 2 diabetes and obesity. The benefit of green tea extract (GTE) consumption still requires confirmation. We report the effects of circulating green tea catechins on blood glucose and insulin levels. Oral glucose loading 1 h after GTE ingestion in humans led to higher blood glucose and insulin levels than in control subjects. Gallated catechins were required for these effects, although within the intestinal lumen they have been known to decrease glucose and cholesterol absorption. Treatment with epigallocatechin-3-gallate hindered 2-deoxyglucose uptake into liver, fat, pancreatic beta-cell, and skeletal muscle cell lines. The glucose intolerance was ameliorated by gallated catechin-deficient GTE or GTE mixed with polyethylene glycol, which was used as an inhibitor of intestinal absorption of gallated catechins. These findings may suggest that the gallated catechin when it is in the circulation elevates blood glucose level by blocking normal glucose uptake into the tissues, resulting in secondary hyperinsulinemia, whereas it decreases glucose entry into the circulation when they are inside the intestinal lumen. These findings encourage the development of non-absorbable derivatives of gallated catechins for preventative treatment of type 2 diabetes and obesity, which would specifically induce only the positive luminal effect.

  18. Human systemic exposure to [14C]-paraphenylenediamine-containing oxidative hair dyes: Absorption, kinetics, metabolism, excretion and safety assessment

    NARCIS (Netherlands)

    Nohynek, G.J.; Skare, J.A.; Meuling, W.J.A.; Wehmeyer, K.R.; Bie, A.T.H.J. de; Vaes, W.H.J.; Dufour, E.K.; Fautz, R.; Steiling, W.; Bramante, M.; Toutain, H.

    2015-01-01

    Systemic exposure was measured in humans after hair dyeing with oxidative hair dyes containing 2.0% (A) or 1.0% (B) [14C]-p-phenylenediamine (PPD). Hair was dyed, rinsed, dried, clipped and shaved; blood and urine samples were collected for 48 hours after application. [14C] was measured in all

  19. Localized specific absorption rate in the human head in metal-framed spectacles for 1.5GHz hand-held mobile telephones

    Energy Technology Data Exchange (ETDEWEB)

    Wang, J.; Joko, T.; Fujikawa, O. [Nagoya Institute of Technology, Nagoya (Japan)

    1998-11-01

    Enhancements of the localized specific absorption rate (SAR) caused by metal-framed spectacles are analyzed numerically for 1.5 GHz hand-held mobile telephones. The finite-difference time-domain (FDTD) method and an anatomically based human head model are employed in the analysis. Enhancements up to 1.2 times for the ten-gram-averaged spatial peak SAR in the head and up to 2.75 times for the one-gram-averaged SAR in the eye are found, whereas there is no significant variation on the absorbed power or averaged SAR in the whole head. The mechanism of localized SAR enhancement is clarified to be due to an induced current on the metal frame. 17 refs., 8 figs., 2 tabs.

  20. Comparison of colorimetry and electrothermal atomic absorption spectroscopy for the quantification of non-transferrin bound iron in human sera.

    Science.gov (United States)

    Jittangprasert, Piyada; Wilairat, Prapin; Pootrakul, Pensri

    2004-12-01

    This paper describes a comparison of two analytical techniques, one employing bathophenanthrolinedisulfonate (BPT), a most commonly-used reagent for Fe (II) determination, as chromogen and an electrothermal atomic absorption spectroscopy (ETAAS) for the quantification of non-transferrin bound iron (NTBI) in sera from thalassemic patients. Nitrilotriacetic acid (NTA) was employed as the ligand for binding iron from low molecular weight iron complexes present in the serum but without removing iron from the transferrin protein. After ultrafiltration the Fe (III)-NTA complex was then quantified by both methods. Kinetic study of the rate of the Fe (II)-BPT complex formation for various excess amounts of NTA ligand was also carried out. The kinetic data show that a minimum time duration (> 60 minutes) is necessary for complete complex formation when large excess of NTA is used. Calibration curves given by colorimetric and ETAAS methods were linear over the range of 0.15-20 microM iron (III). The colorimetric and ETAAS methods exhibited detection limit (3sigma) of 0.13 and 0.14 microM, respectively. The NTBI concentrations from 55 thalassemic serum samples measured employing BPT as chromogen were statistically compared with the results determined by ETAAS. No significant disagreement at 95% confidence level was observed. It is, therefore, possible to select any one of these two techniques for determination of NTBI in serum samples of thalassemic patients. However, the colorimetric procedure requires a longer analysis time because of a slow rate of exchange of NTA ligand with BPT, leading to the slow rate of formation of the colored complex.

  1. Deep-apical tubules: dynamic lipid-raft microdomains in the brush-border region of enterocytes

    DEFF Research Database (Denmark)

    Hansen, Gert H; Pedersen, Jens; Niels-Christiansen, Lise-Lotte

    2003-01-01

    microdomains. Deep-apical tubules were positioned close to the actin rootlets of adjacent microvilli in the terminal web region, which had a diameter of 50-100 nm, and penetrated up to 1 microm into the cytoplasm. Markers for transcytosis, IgA and the polymeric immunoglobulin receptor, as well as the resident...... lipid raft-containing compartments, but little is otherwise known about these raft microdomains. We therefore studied in closer detail apical lipid-raft compartments in enterocytes by immunogold electron microscopy and biochemical analyses. Novel membrane structures, deep-apical tubules, were visualized...... brush-border enzyme aminopeptidase N, were present in these deep-apical tubules. We propose that deep-apical tubules are a specialized lipid-raft microdomain in the brush-border region functioning as a hub in membrane trafficking at the brush border. In addition, the sensitivity to cholesterol depletion...

  2. Effect of ultrasound and heat on percutaneous absorption of l-ascorbic acid: human in vitro studies on Franz cell and Petri dish systems.

    Science.gov (United States)

    Jung, E C; Zhu, H; Zou, Y; Elmahdy, A; Cao, Y; Hui, X; Maibach, H I

    2016-12-01

    Percutaneous absorption of l-ascorbic acid (LAA) is limited due to its high hydrophilicity and low stability. Here, we investigated the effect of post-dosing sonophoresis (329 kHz, 20 mW cm(-2) ) and heat (36°C) on transdermal delivery of LAA. Ultrasound/heat, heat and control treatments were applied on skin surface for 2 and 5 min after topical application of C14-labelled LAA aqueous solution. After 15 min post-exposure, radioactivity was measured in tape-striped stratum corneum (TS-SC), epidermis, dermis and receptor fluid. As Franz diffusion cell model may have different acoustic response than in vivo human tissues, a novel Petri dish model was developed and compared with Franz cell model on the effects of ultrasound/heat treatment on the skin permeability. Five-min ultrasound/heat treatment significantly accelerated skin absorption/penetration of LAA; 2-min treatment showed no enhancement effect on Franz diffusion cell model at the end of experiment. The use of Petri dish model significantly increased LAA concentrations in epidermis after 5 min of ultrasound/heat treatment, compared to the results of Franz cell model. Combination of ultrasound (329 kHz, 20 mW cm(-2) ) and heat (36°C) significantly enhanced LAA transdermal penetration, when the time of treatment was sufficient (5 min). As Petri dish model was designed to simulate acoustic respond of dense human tissue to ultrasound, the difference between Franz cell and Petri dish models suggests that the enhancement effect of ultrasound/heat on skin penetration in vivo may be greater than that determined on in vitro Franz cell model. © 2016 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

  3. The dielectric properties of human pineal gland tissue and RF absorption due to wireless communication devices in the frequency range 400-1850 MHz

    Energy Technology Data Exchange (ETDEWEB)

    Schmid, Gernot [Austrian Research Centers GmbH-ARC, ITM, A-2444 Seibersdorf (Austria); Ueberbacher, Richard [Austrian Research Centers GmbH-ARC, ITM, A-2444 Seibersdorf (Austria); Samaras, Theodoros [Department of Physics, Aristotle University of Thessaloniki, GR-54124 Thessaloniki (Greece); Tschabitscher, Manfred [Center of Anatomy and Cell Biology, Medical University of Vienna, A-1090 Vienna (Austria); Mazal, Peter R [Department of Clinical Pathology, Medical University Vienna, A-1090 Vienna (Austria)

    2007-09-07

    In order to enable a detailed analysis of radio frequency (RF) absorption in the human pineal gland, the dielectric properties of a sample of 20 freshly removed pineal glands were measured less than 20 h after death. Furthermore, a corresponding high resolution numerical model of the brain region surrounding the pineal gland was developed, based on a real human tissue sample. After inserting this model into a commercially available numerical head model, FDTD-based computations for exposure scenarios with generic models of handheld devices operated close to the head in the frequency range 400-1850 MHz were carried out. For typical output power values of real handheld mobile communication devices, the obtained results showed only very small amounts of absorbed RF power in the pineal gland when compared to SAR limits according to international safety standards. The highest absorption was found for the 400 MHz irradiation. In this case the RF power absorbed inside the pineal gland (organ mass 96 mg) was as low as 11 {mu}W, when considering a device of 500 mW output power operated close to the ear. For typical mobile phone frequencies (900 MHz and 1850 MHz) and output power values (250 mW and 125 mW) the corresponding values of absorbed RF power in the pineal gland were found to be lower by a factor of 4.2 and 36, respectively. These results indicate that temperature-related biologically relevant effects on the pineal gland induced by the RF emissions of typical handheld mobile communication devices are unlikely.

  4. Enterocyte-specific inactivation of SIRT1 reduces tumor load in the APC(+/min mouse model.

    Directory of Open Access Journals (Sweden)

    Vid Leko

    Full Text Available SIRT1 is a mammalian NAD(+-dependent histone deacetylase implicated in metabolism, development, aging and tumorigenesis. Prior studies that examined the effect of enterocyte-specific overexpression and global deletion of SIRT1 on polyp formation in the intestines of APC(+/min mice, a commonly used model for intestinal tumorigenesis, yielded conflicting results, supporting either tumor-suppressive or tumor-promoting roles for SIRT1, respectively. In order to resolve the controversy emerging from these prior in vivo studies, in the present report we examined the effect of SIRT1 deficiency confined to the intestines, avoiding the systemic perturbations such as growth retardation seen with global SIRT1 deletion. We crossed APC(+/min mice with mice bearing enterocyte-specific inactivation of SIRT1 and examined polyp development in the progeny. We found that SIRT1-inactivation reduced total polyp surface (9.3 mm(2 vs. 23.3 mm(2, p = 0.01, average polyp size (0.24 mm(2 vs. 0.51 mm(2, p = 0.005 and the number of polyps >0.5 mm in diameter (14 vs. 23, p = 0.04, indicating that SIRT1 affects both the number and size of tumors. Additionally, tumors in SIRT1-deficient mice exhibited markedly increased numbers of cells undergoing apoptosis, suggesting that SIRT1 contributes to tumor growth by enabling survival of tumor cells. Our results indicate that SIRT1 acts as a tumor promoter in the APC(+/min mouse model of intestinal tumorigenesis.

  5. Assessment of chemical species of lead accumulated in tidemarks of human articular cartilage by X-ray absorption near-edge structure analysis

    Energy Technology Data Exchange (ETDEWEB)

    Meirer, Florian [Atominstitut, Vienna University of Technology, 1020 Wien (Austria); MiNALab, CMM-Irst, Fondazione Bruno Kessler, Via Sommarive 18, 38123 Trento (Italy); Pemmer, Bernhard, E-mail: bpemmer@ati.ac.at [Atominstitut, Vienna University of Technology, 1020 Wien (Austria); Pepponi, Giancarlo [MiNALab, CMM-Irst, Fondazione Bruno Kessler, Via Sommarive 18, 38123 Trento (Italy); Zoeger, Norbert; Wobrauschek, Peter [Atominstitut, Vienna University of Technology, 1020 Wien (Austria); Sprio, Simone; Tampieri, Anna [Istituto di Scienza e Tecnologia dei Materiali Ceramici CNR, Faenca (Italy); Goettlicher, Joerg; Steininger, Ralph; Mangold, Stefan [Institute for Synchrotron Radiation, Karlsruhe Institute of Technology, Campus South, 76344 Eggenstein-Leopoldshafen (Germany); Roschger, Paul [Ludwig Boltzmann Institute of Osteology, Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, 4th Medical Department, Hanusch Hospital, Vienna (Austria); Berzlanovich, Andrea [Department of Forensic Medicine, Medical University of Vienna, A-1090 Vienna (Austria); Hofstaetter, Jochen G. [Ludwig Boltzmann Institute of Osteology, Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, 4th Medical Department, Hanusch Hospital, Vienna (Austria); Department of Orthopaedics, Vienna General Hospital, Medical University of Vienna, A-1090 Vienna (Austria); Streli, Christina [Atominstitut, Vienna University of Technology, 1020 Wien (Austria)

    2011-03-01

    Lead is a toxic trace element that shows a highly specific accumulation in the transition zone between calcified and non-calcified articular cartilage, the so-called ‘tidemark’. Excellent agreement has been found between XANES spectra of synthetic Pb-doped carbonated hydroxyapatite and spectra obtained in the tidemark region and trabecular bone of normal human samples, confirming that in both tissues Pb is incorporated into the hydroxyapatite crystal structure of bone. During this study the µ-XANES set-up at the SUL-X beamline at ANKA was tested and has proven to be well suited for speciation of lead in human mineralized tissue samples. A highly specific accumulation of the toxic element lead was recently measured in the transition zone between non-calcified and calcified normal human articular cartilage. This transition zone, the so-called ‘tidemark’, is considered to be an active calcification front of great clinical importance. However, little is known about the mechanisms of accumulation and the chemical form of Pb in calcified cartilage and bone. Using spatially resolved X-ray absorption near-edge structure analysis (µ-XANES) at the Pb L{sub 3}-edge, the chemical state of Pb in the osteochondral region was investigated. The feasibility of the µ-XANES set-up at the SUL-X beamline (ANKA synchrotron light source) was tested and confirmed by comparing XANES spectra of bulk Pb-reference compounds recorded at both the XAS and the SUL-X beamline at ANKA. The µ-XANES set-up was then used to investigate the tidemark region of human bone (two patella samples and one femoral head sample). The spectra recorded at the tidemark and at the trabecular bone were found to be highly correlated with the spectra of synthetic Pb-doped carbonated hydroxyapatite, suggesting that in both of these very different tissues Pb is incorporated into the hydroxyapatite structure.

  6. Glucagon-like peptide 2 stimulates glucagon secretion, enhances lipid absorption, and inhibits gastric acid secretion in humans

    DEFF Research Database (Denmark)

    Meier, Juris J; Nauck, Michael A; Pott, Andrea

    2006-01-01

    or placebo during the ingestion of a solid test meal. Gastric emptying was determined using a 13C-sodium-octanote breath test. Plasma concentrations of glucose, insulin, C-peptide, glucagon, GLP-2, free fatty acids, free glycerol, and triglycerides were determined. RESULTS: GLP-2 administration led......BACKGROUND & AIMS: The gut-derived peptide glucagon-like peptide 2 (GLP-2) has been suggested as a potential drug candidate for the treatment of various intestinal diseases. However, the acute effects of GLP-2 on gastric functions as well as on glucose and lipid homeostasis in humans are less well...... to a marked increase in glucagon concentrations both in the fasting state and during the meal study (P plasma concentrations of triglycerides and free fatty acids were significantly higher during GLP-2 infusion compared with placebo (P

  7. Bixin and norbixin in human plasma: determination and study of the absorption of a single dose of Annatto food color.

    Science.gov (United States)

    Levy, L W; Regalado, E; Navarrete, S; Watkins, R H

    1997-09-01

    A procedure was developed for the detection and determination of bixin and norbixin in human plasma by reversed-phase HPLC with a sensitivity limit of 5 micrograms l-1. A group of seven volunteers ingested a single dose of 1 ml of a commercial Annatto Food Color (16 mg of cis-bixin in soybean oil). The presence of bixin (cis and trans) and norbixin (cis and trans) was demonstrated in the plasma at average levels of 11.6, 10.1, 2.8 and 0 micrograms l-1 of bixin and 48, 58, 53 and 29 micrograms l-1 of norbixin after 2, 4, 6 and 8 h, respectively. Considerable individual variations were observed. Complete plasma clearance generally occurred for bixin by 8 h and for norbixin by 24 h after ingestion of cis-bixin.

  8. Analysis of specific absorption rate and current density in biological tissues surrounding energy transmission transformer for an artificial heart: using magnetic resonance imaging-based human body model.

    Science.gov (United States)

    Higaki, Naoya; Shiba, Kenji

    2010-01-01

    The transcutaneous energy transmission system used for artificial hearts is a transmission system that uses electromagnetic induction. Use of the TETS improves quality of life and reduces the risk of infection caused by percutaneous connections. This article reports the changes in the electromagnetic effects of TETS that influence a human body when the locations of the air-core coils of the transcutaneous transformer are changed. The specific absorption rate and current density in a model consisting of a human trunk that included 24 different organs are analyzed using an electromagnetic simulator. The air-core coils are located on the pectoralis major muscle near the collarbone in model 1, whereas they are located on the axillary region of the serratus anterior muscle, which overlies the rib in model 2. The maximum current densities in models 1 and 2 are 5.2 A/m(2) and 6.1 A/m(2), respectively. The current density observed in model 2 slightly exceeds the limiting value prescribed by International Commission on Non-Ionizing Radiation Protection (ICNIRP). When the volumes of biological tissues whose current densities exceed the limiting value of current density for general public exposure are compared, the volume in model 2 (156.1 cm(3)) is found to be larger than that in model 1 (93.7 cm(3)). Hence, it is speculated that the presence of the ribs caused an increase in the current density. Therefore, it is concluded that model 1 satisfies the ICNIRP standards.

  9. Direct extraction of lead (II) from untreated human blood serum using restricted access carbon nanotubes and its determination by atomic absorption spectrometry.

    Science.gov (United States)

    Barbosa, Valéria Maria Pereira; Barbosa, Adriano Francisco; Bettini, Jefferson; Luccas, Pedro Orival; Figueiredo, Eduardo Costa

    2016-01-15

    Oxidized carbon nanotubes were covered with layers of bovine serum albumin to result in so-called restricted-access carbon nanotubes (RACNTs). This material can extract Pb(2+) ions directly from untreated human blood serum while excluding all the serum proteins. The RACNTs have a protein exclusion capacity of almost 100% and a maximum Pb(2+) adsorption capacity of 34.5mg g(-1). High resolution transmission electron microscopy, scanning transmission electron microscopy and energy dispersive spectroscopy were used to confirm the BSA layer and Pb(2+) adsorption sites. A mini-column filled with RACNTs was used in an on-line solid phase extraction system coupled to a thermospray flame furnace atomic absorption spectrometry. At optimized experimental conditions, the method has a detection limit as low as 2.1µg L(-1), an enrichment factor of 5.5, and inter- and intra-day precisions (expressed as relative standard deviation) of <8.1%. Recoveries of the Pb(2+) spiked samples ranged from 89.4% to 107.3% for the extraction from untreated human blood serum. Copyright © 2015 Elsevier B.V. All rights reserved.

  10. Analysis of specific absorption rate and internal electric field in human biological tissues surrounding an air-core coil-type transcutaneous energy transmission transformer.

    Science.gov (United States)

    Shiba, Kenji; Zulkifli, Nur Elina Binti; Ishioka, Yuji

    2017-06-01

    In this study, we analyzed the internal electric field E and specific absorption rate (SAR) of human biological tissues surrounding an air-core coil transcutaneous energy transmission transformer. Using an electromagnetic simulator, we created a model of human biological tissues consisting of a dry skin, wet skin, fat, muscle, and cortical bone. A primary coil was placed on the surface of the skin, and a secondary coil was located subcutaneously inside the body. The E and SAR values for the model representing a 34-year-old male subject were analyzed using electrical frequencies of 0.3-1.5 MHz. The transmitting power was 15 W, and the load resistance was 38.4 Ω. The results showed that the E values were below the International Commission on Non-ionizing Radiation Protection (ICNIRP) limit for the general public exposure between the frequencies of 0.9 and 1.5 MHz, and SAR values were well below the limit prescribed by the ICNIRP for the general public exposure between the frequencies of 0.3 and 1.2 MHz.

  11. Rapid and simultaneous determination of essential minerals and trace elements in human milk by improved flame atomic absorption spectroscopy (FAAS) with microwave digestion.

    Science.gov (United States)

    Luo, Yang; Zhang, Bo; Chen, Ming; Wang, Jue; Zhang, Xue; Gao, Wei-Yin; Huang, Jun-Fu; Fu, Wei-Ling

    2010-09-08

    A method for the simultaneous and economical determination of many trace elements in human milk is developed. Two multi-element hollow cathode lamps (HCLs) were used instead of single-element HCLs to improve the sample throughput of flame atomic absorption spectroscopy (FAAS). The microwave digestion of milk is optimized prior to detection, and the performance characteristics of the improved analysis method are identified. Clinical samples are detected by both FAAS and inductively coupled plasma-optical emission spectroscopy (ICP-OES) for methodology evaluation. Results reveal that the proposed FAAS with multi-element HCLs could determine six essential minerals and trace elements within 15 min. This method provides a linear analytical range of 0.01-10 mg L(-1). For Ca, Cu, Fe, Mg, Mn, and Zn, the limits of determination are 1.5, 3, 1.8, 2.2, 2.1, and 1.3 microg L(-1), respectively. The mean relative standard deviations (RSDs) of intra- and interassays are lower than 7%. Excellent operational characteristics of rapidity, simplicity, and economy make the proposed method a promising one for the quantification of trace elements in human milk in clinics of underdeveloped areas.

  12. The Shiga toxin 2 B subunit inhibits net fluid absorption in human colon and elicits fluid accumulation in rat colon loops

    Directory of Open Access Journals (Sweden)

    V. Pistone Creydt

    2004-06-01

    Full Text Available Shiga toxin (Stx-producing Escherichia coli (STEC colonizes the large intestine causing a spectrum of disorders, including watery diarrhea, bloody diarrhea (hemorrhagic colitis, and hemolytic-uremic syndrome. It is estimated that hemolytic-uremic syndrome is the most common cause of acute renal failure in infants in Argentina. Stx is a multimeric toxin composed of one A subunit and five B subunits. In this study we demonstrate that the Stx2 B subunit inhibits the water absorption (Jw across the human and rat colonic mucosa without altering the electrical parameters measured as transepithelial potential difference and short circuit current. The time-course Jw inhibition by 400 ng/ml purified Stx2 B subunit was similar to that obtained using 12 ng/ml Stx2 holotoxin suggesting that both, A and B subunits of Stx2 contributed to inhibit the Jw. Moreover, non-hemorrhagic fluid accumulation was observed in rat colon loops after 16 h of treatment with 3 and 30 ng/ml Stx2 B subunit. These changes indicate that Stx2 B subunit induces fluid accumulation independently of A subunit activity by altering the usual balance of intestinal absorption and secretion toward net secretion. In conclusion, our results suggest that the Stx2 B subunit, which is non-toxic for Vero cells, may contribute to the watery diarrhea observed in STEC infection. Further studies will be necessary to determine whether the toxicity of Stx2 B subunit may have pathogenic consequences when it is used as a component in an acellular STEC vaccine or as a vector in cancer vaccines.

  13. Domains of increased thickness in microvillar membranes of the small intestinal enterocyte

    DEFF Research Database (Denmark)

    Kunding, Andreas H; Christensen, Sune M; Danielsen, E Michael

    2010-01-01

    was clearly monophasic. The encountered domains of increased thickness (DITs) occupied 48% of the microvillar membrane and from the data we estimated the area of a single DIT to have a lower limit of 600 nm(2). In other experiments we mapped the organization of biochemically defined lipid rafts by immunogold...... in orchestrating absorptive/digestive action of dietary nutrients at this important cellular interface. Increased membrane thickness is believed to be a morphological characteristic of rafts. Thus, we investigated whether the high contents of lipid rafts in the microvillar membrane is reflected in local variations...... in membrane thickness. We measured membrane thickness directly from electron micrographs of sections of fixed mucosal tissue. Indeed, mapping of the microvillar membrane revealed a biphasic distribution of membrane thickness. As a point of reference the thickness distribution of the basolateral membrane...

  14. Effect of recombinant human growth hormone on intestinal absorption and body composition in children with short bowel syndrome.

    Science.gov (United States)

    Goulet, Olivier; Dabbas-Tyan, Myriam; Talbotec, Cécile; Kapel, Nathalie; Rosilio, Myriam; Souberbielle, Jean-Claude; Corriol, Odile; Ricour, Claude; Colomb, Virginie

    2010-01-01

    This prospective study aimed to establish the effect of recombinant human growth hormone (rhGH) on intestinal function in children with short bowel syndrome (SBS). Eight children with neonatal SBS were included. All were dependent on parenteral nutrition (PN) for >3 years (range, 3.8-11.6 years), with PN providing >50% of recommended dietary allowance for age (range, 50%-65%). The subjects received rhGH (Humatrope) 0.13 mg/kg/d subcutaneously over a 12-week period. The follow-up was continued over a 12-month period after rhGH discontinuation. Clinical and biological assessments were performed at baseline, at the end of the treatment period, and 12 months after the end of treatment. No side effects related to rhGH were observed. PN requirements were decreased in all children during the course of rhGH treatment. Between baseline and the end of treatment, significant increases were observed in concentrations (mean ± standard deviation) of serum insulin-like growth factor 1 (103.1 ± 49.9 µg/L vs 153.5 ± 82.2 µg/L; P children to be maintained on PN or restarted after discontinuation of rhGH treatment, and they remained on PN until the end of the follow-up period. A 12-week high-dose rhGH treatment allowed patients to decrease PN, but only 2 patients could be definitively weaned from PN. Indications and cost-effectiveness of rhGH treatment for SBS pediatric patients need further evaluation.

  15. Inhibition of water absorption and selective damage to human colonic mucosa induced by Shiga toxin-2 are enhanced by Escherichia coli O157:H7 infection.

    Science.gov (United States)

    Albanese, Adriana; Gerhardt, Elizabeth; García, Hugo; Amigo, Natalia; Cataldi, Angel; Zotta, Elsa; Ibarra, Cristina

    2015-05-01

    Shiga toxin-producing Escherichia coli (STEC) strains are responsible for a variety of clinical syndromes including bloody and non-bloody diarrhea, hemorrhagic colitis, and hemolytic uremic syndrome (HUS). Although multiple serotypes of STEC have been isolated from hemorrhagic colitis cases, E. coli O157:H7 is by far the most prevalent serotype associated with HUS. Shiga toxin is the major virulence factor of E. coli O157:H7 and is responsible for the more severe symptoms of the infection. However, the mechanisms involved in the pathogenesis of diarrhea mediated by Stx2 are not well known. In this study, we have determined the effects of E. coli O157:H7 strain 125/99 wild type (wt) on the human colonic mucosa mounted in an Ussing chamber. In response to 125/99wt, an inhibition of water absorption across human colonic mucosa was observed. Histological sections showed severe necrosis with detachment of the surface epithelium, mononuclear inflammatory infiltrate and loss of goblet cells after 1h of incubation with 125/99wt. These alterations were not observed with the isogenic mutant strain lacking stx2 or with the filter-sterilized culture supernatant from the 125/99wt strain. These results indicate that the cell damages in human colon are induced by Stx2, and that Stx2 production is increased by the interaction with bacterial cells. Identification of host cell-derived factors responsible for increasing Stx2 can lead to new strategies for modulating STEC infections. Copyright © 2015 Elsevier GmbH. All rights reserved.

  16. Analysis of global and absorption, distribution, metabolism, and elimination gene expression in the progressive stages of human nonalcoholic fatty liver disease.

    Science.gov (United States)

    Lake, April D; Novak, Petr; Fisher, Craig D; Jackson, Jonathan P; Hardwick, Rhiannon N; Billheimer, D Dean; Klimecki, Walter T; Cherrington, Nathan J

    2011-10-01

    Nonalcoholic fatty liver disease (NAFLD) is characterized by a series of pathological changes that range from simple fatty liver to nonalcoholic steatohepatitis (NASH). The objective of this study is to describe changes in global gene expression associated with the progression of human NAFLD. This study is focused on the expression levels of genes responsible for the absorption, distribution, metabolism, and elimination (ADME) of drugs. Differential gene expression between three clinically defined pathological groups-normal, steatosis, and NASH-was analyzed. Genome-wide mRNA levels in samples of human liver tissue were assayed with Affymetrix GeneChip Human 1.0ST arrays. A total of 11,633 genes exhibited altered expression out of 33,252 genes at a 5% false discovery rate. Most gene expression changes occurred in the progression from steatosis to NASH. Principal component analysis revealed that hepatic disease status was the major determinant of differential ADME gene expression rather than age or sex of sample donors. Among the 515 drug transporters and 258 drug-metabolizing enzymes (DMEs) examined, uptake transporters but not efflux transporters or DMEs were significantly over-represented in the number of genes down-regulated. These results suggest that uptake transporter genes are coordinately targeted for down-regulation at the global level during the pathological development of NASH and that these patients may have decreased drug uptake capacity. This coordinated regulation of uptake transporter genes is indicative of a hepatoprotective mechanism acting to prevent accumulation of toxic intermediates in disease-compromised hepatocytes.

  17. FDTD calculations of specific energy absorption rate in a seated voxel model of the human body from 10 MHz to 3 GHz

    Energy Technology Data Exchange (ETDEWEB)

    Findlay, R P; Dimbylow, P J [Health Protection Agency, Chilton, Didcot, Oxon OX11 0RQ (United Kingdom)

    2006-05-07

    Finite-difference time-domain (FDTD) calculations have been performed to investigate the frequency dependence of the specific energy absorption rate (SAR) in a seated voxel model of the human body. The seated model was derived from NORMAN (NORmalized MAN), an anatomically realistic voxel phantom in the standing posture with arms to the side. Exposure conditions included both vertically and horizontally polarized plane wave electric fields between 10 MHz and 3 GHz. The resolution of the voxel model was 4 mm for frequencies up to 360 MHz and 2 mm for calculations in the higher frequency range. The reduction in voxel size permitted the calculation of SAR at these higher frequencies using the FDTD method. SAR values have been calculated for the seated adult phantom and scaled versions representing 10-, 5- and 1-year-old children under isolated and grounded conditions. These scaled models do not exactly reproduce the dimensions and anatomy of children, but represent good geometric information for a seated child. Results show that, when the field is vertically polarized, the sitting position causes a second, smaller resonance condition not seen in resonance curves for the phantom in the standing posture. This occurs at {approx}130 MHz for the adult model when grounded. Partial-body SAR calculations indicate that the upper and lower regions of the body have their own resonant frequency at {approx}120 MHz and {approx}160 MHz, respectively, when the grounded adult model is orientated in the sitting position. These combine to produce this second resonance peak in the whole-body averaged SAR values calculated. Two resonance peaks also occur for the sitting posture when the incident electric field is horizontally polarized. For the adult model, the peaks in the whole-body averaged SAR occur at {approx}180 and {approx}600 MHz. These peaks are due to resonance in the arms and feet, respectively. Layer absorption plots and colour images of SAR in individual voxels show the

  18. FDTD calculations of specific energy absorption rate in a seated voxel model of the human body from 10 MHz to 3 GHz.

    Science.gov (United States)

    Findlay, R P; Dimbylow, P J

    2006-05-07

    Finite-difference time-domain (FDTD) calculations have been performed to investigate the frequency dependence of the specific energy absorption rate (SAR) in a seated voxel model of the human body. The seated model was derived from NORMAN (NORmalized MAN), an anatomically realistic voxel phantom in the standing posture with arms to the side. Exposure conditions included both vertically and horizontally polarized plane wave electric fields between 10 MHz and 3 GHz. The resolution of the voxel model was 4 mm for frequencies up to 360 MHz and 2 mm for calculations in the higher frequency range. The reduction in voxel size permitted the calculation of SAR at these higher frequencies using the FDTD method. SAR values have been calculated for the seated adult phantom and scaled versions representing 10-, 5- and 1-year-old children under isolated and grounded conditions. These scaled models do not exactly reproduce the dimensions and anatomy of children, but represent good geometric information for a seated child. Results show that, when the field is vertically polarized, the sitting position causes a second, smaller resonance condition not seen in resonance curves for the phantom in the standing posture. This occurs at approximately 130 MHz for the adult model when grounded. Partial-body SAR calculations indicate that the upper and lower regions of the body have their own resonant frequency at approximately 120 MHz and approximately 160 MHz, respectively, when the grounded adult model is orientated in the sitting position. These combine to produce this second resonance peak in the whole-body averaged SAR values calculated. Two resonance peaks also occur for the sitting posture when the incident electric field is horizontally polarized. For the adult model, the peaks in the whole-body averaged SAR occur at approximately 180 and approximately 600 MHz. These peaks are due to resonance in the arms and feet, respectively. Layer absorption plots and colour images of SAR in

  19. The relationship between specific absorption rate and temperature elevation in anatomically based human body models for plane wave exposure from 30 MHz to 6 GHz

    Science.gov (United States)

    Hirata, Akimasa; Laakso, Ilkka; Oizumi, Takuya; Hanatani, Ryuto; Chan, Kwok Hung; Wiart, Joe

    2013-02-01

    According to the international safety guidelines/standard, the whole-body-averaged specific absorption rate (Poljak et al 2003 IEEE Trans. Electromagn. Compat. 45 141-5) and the peak spatial average SAR are used as metrics for human protection from whole-body and localized exposures, respectively. The IEEE standard (IEEE 2006 IEEE C95.1) indicates that the upper boundary frequency, over which the whole-body-averaged SAR is deemed to be the basic restriction, has been reduced from 6 to 3 GHz, because radio-wave energy is absorbed around the body surface when the frequency is increased. However, no quantitative discussion has been provided to support this description especially from the standpoint of temperature elevation. It is of interest to investigate the maximum temperature elevation in addition to the core temperature even for a whole-body exposure. In the present study, using anatomically based human models, we computed the SAR and the temperature elevation for a plane-wave exposure from 30 MHz to 6 GHz, taking into account the thermoregulatory response. As the primary result, we found that the ratio of the core temperature elevation to the whole-body-averaged SAR is almost frequency independent for frequencies below a few gigahertz; the ratio decreases above this frequency. At frequencies higher than a few gigahertz, core temperature elevation for the same whole-body averaged SAR becomes lower due to heat convection from the skin to air. This lower core temperature elevation is attributable to skin temperature elevation caused by the power absorption around the body surface. Then, core temperature elevation even for whole-body averaged SAR of 4 W kg-1 with the duration of 1 h was at most 0.8 °C, which is smaller than a threshold considered in the safety guidelines/standard. Further, the peak 10 g averaged SAR is correlated with the maximum body temperature elevations without extremities and pinna over the frequencies considered. These findings were confirmed

  20. Quantitative analysis of absorption, metabolism, and excretion of benzoxazinoids in humans after the consumption of high- and low-benzoxazinoid diets with similar contents of cereal dietary fibres: a crossover study

    DEFF Research Database (Denmark)

    Jensen, Bettina M.; B. Adhikari, Khem; Schnoor, Heidi J.

    2017-01-01

    PURPOSE: Benzoxazinoids (BXs) are a group of wholegrain phytochemicals with potential pharmacological properties; however, limited information exists on their absorption, metabolism, and excretion in humans. The aim of this study was to investigate the dose-dependent uptake and excretion of dietary...

  1. The two-component system CpxRA negatively regulates the Locus of Enterocyte Effacement of enterohemorrhagic Escherichia coli involving sigma 32 and Lon protease

    Directory of Open Access Journals (Sweden)

    MIGUEL A. eDE LA CRUZ

    2016-02-01

    Full Text Available Enterohemorrhagic Escherichia coli (EHEC is a significant cause of serious human gastrointestinal disease worldwide. EHEC strains contain a pathogenicity island called the locus of enterocyte effacement (LEE, which encodes virulence factors responsible for damaging the gut mucosa. The Cpx envelope stress response of E. coli is controlled by a two-component system consisting of a sensor histidine kinase (CpxA and a cytoplasmic response regulator (CpxR. In this study, we investigated the role of CpxRA in the expression of LEE-encoded virulence factors of EHEC. We found that a mutation in cpxA significantly affected adherence of EHEC to human epithelial cells. Analysis of this mutant revealed the presence of high levels of CpxR which repressed transcription of grlA and ler, the main positive virulence regulators of the LEE, and influenced negatively the production of the type 3 secretion system–associated EspABD translocator proteins. It is known that CpxR activates rpoH (Sigma factor 32, which in turns activates transcription of the lon protease gene. We found that transcription levels of ler and grlA were significantly increased in the lon and cpxA lon mutants suggesting that lon is involved in down-regulating LEE genes. In addition, the Galleria mellonella model of infection was used to analyze the effect of the loss of the cpx and lon genes in EHEC’s ability to kill the larvae. We found that the cpxA mutant was significantly deficient at killing the larvae however, the cpxA lon mutant which overexpresses LEE genes in vitro, was unable to kill the larvae, suggesting that virulence in the G. mellonella model is T3SS independent and that CpxA modulates virulence through a yet unknown EHEC-specific factor. Our data provides new insights and broadens our scope into the complex regulatory network of the LEE in which the CpxA sensor kinase plays an important role in a cascade involving both global and virulence regulators.

  2. The role of cyclooxygenase-1 and cyclooxygenase-2 in lipopolysaccharide and interleukin-1 stimulated enterocyte prostanoid formation

    Directory of Open Access Journals (Sweden)

    W. E. Longo

    1998-01-01

    Full Text Available Lipopolysaccharide is an inflammatory agent and interleukin-1 is a cytokine. Their pro-inflammatory effects may be mediated by prostanoids produced by inducible cyclooxygenase-2. The aim of this study was to determine the prostanoids produced by lipopolysaccharide and interleukin-1 stimulated enterocytes through the cyclooxygenase-1 and 2 pathways. Cultured enterocytes were stimulated with lipopolysaccharide or interleukin-1 β with and without cyclooxygenase inhibitors. Low concentrations of indomethacin and valerylsalicylic acid (VSA were evaluated as cyclooxygenase-1 inhibitors and their effects compared with the effects of a specific cyclooxygenase-2 inhibitor, SC-58125. Prostaglandin E2 , 6-keto prostaglandin F1α , prostaglandin D2 and leukotriene B4 levels were determined by radio immunoassay. Immunoblot analysis using isoformspecific antibodies showed that the inducible cyclooxygenase enzyme (COX-2 was expressed by 4 h in LPS and IL-1β treated cells while the constitutive COX-1 remained unaltered in its expression. Interleukin-1β and lipopolysaccharide stimulated the formation of all prostanoids compared with untreated cells, but failed to stimulate leukotriene B4. Indomethacin at 20 μ M concentration, and VSA inhibited lipopolysaccharide and interleukin 1β stimulated prostaglandin E2 , but not 6-keto prostaglandin F1α formation. SC-58125 inhibited lipopolysaccharide and interleukin-1β stimulated 6-keto prostaglandin F1α but not prostaglandin E2 release. The specific cyclooxygenase-2 inhibitor also inhibited lipopolysaccharide produced prostaglandin D2 but not interleukin-1β stimulated prostaglandin D2 While SC-58125 inhibited basal 6-keto prostaglandin-F1α formation it significantly increased basal prostaglandin E2 and prostaglandin D2 formation. As SC-58125 inhibited lipopolysaccharide and interleukin-1β induced 6-keto prostaglandin F1α production but not prostaglandin E2 production, it suggests that these agents stimulate

  3. Palladium(II), magnesium(II), and barium(II) nitrate combinations for matrix modification in electrothermal atomic absorption measurement of total selenium in human urine.

    Science.gov (United States)

    Drake, E N; Hain, T D

    1994-08-01

    Electrothermal atomic absorption spectrometry with a temperature-stabilizing platform and palladium(II) nitrate-magnesium nitrate-barium nitrate matrix modifier combination was used to measure total selenium concentrations in 0.5-ml samples of human urine. The method was validated by analysis of desiccated, standard urine samples (SRM 2670) from NIST. The peak height response was linear from 0 to 150 micrograms Se/liter urine with a sensitivity of 0.001 absorbance unit/micrograms Se/liter and a detection limit of 6 micrograms Se/liter (P = 0.05) for a single measurement. Total urinary selenium concentrations and urine volumes of 24-h samples from 28 healthy adult subjects on self-selected diets and living in San Angelo, Texas were measured. Daily total urinary excretions of 16 male and 12 female subjects (mean +/- SD) were 28 +/- 26 and 34 +/- 25 micrograms Se/day, respectively. A single subject taking 300 micrograms Se/day in the form of aqueous SeO2 as a dietary supplement excreted 232 micrograms Se/day. The unsupplemented subjects' daily selenium excretions correspond to a mean dietary intake of approximately 60 micrograms/day.

  4. Validation of a method to quantify chromium, cadmium, manganese, nickel and lead in human whole blood, urine, saliva and hair samples by electrothermal atomic absorption spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Olmedo, P.; Pla, A.; Hernandez, A.F.; Lopez-Guarnido, O.; Rodrigo, L. [Department of Legal Medicine and Toxicology, University of Granada, School of Medicine (Spain); Gil, F., E-mail: fgil@ugr.es [Department of Legal Medicine and Toxicology, University of Granada, School of Medicine (Spain)

    2010-02-05

    For biological monitoring of heavy metal exposure in occupational toxicology, usually whole blood and urine samples are the most widely used and accepted matrix to assess internal xenobiotic exposure. Hair samples and saliva are also of interest in occupational and environmental health surveys but procedures for the determination of metals in saliva and hair are very scarce and to our knowledge there is no validation of a method to quantify Cr, Cd, Mn, Ni and Pb in four different human biological materials (whole blood, urine, saliva and axilary hair) by electrothermal atomization atomic absorption spectrometry (ETAAS). In the present study, quantification methods for the determination of Cr, Cd, Mn, Ni and Pb in whole blood, urine, saliva and axilary hair were validated according to the EU common standards. Pyrolisis and atomization temperatures have been determined. The main parameters evaluated were: detection and quantification limits, linearity range, repeatability, reproducibility, recovery and uncertainty. Accuracy of the methods was tested with the whole blood, urine and hair certified reference materials and recoveries of the spiked samples were acceptable ranged from 96.3 to 107.8%.

  5. Preconcentration and determination of ultra-traces of platinum in human serum using the combined electrodeposition-electrothermal atomic absorption spectroscopy (ED-ETAAS) and chemometric method.

    Science.gov (United States)

    Najafi, Nahid Mashkouri; Shahparvizi, Shahram; Rafati, Hasan; Ghasemi, Ensieh; Alizadeh, Reza

    2010-09-21

    Platinum compounds, including cis-dichlorodiaminoplatinum(II) or cisplatin, are an important class of anti-cancer drugs, which should be carefully monitored in the biological fluids. In this study, electrodeposition coupled with electrothermal atomic absorption spectrometry (ETAAS) was used for determination of Pt concentration in the human serum samples. The chemometric techniques were also used to verify the probable interactions among the important and effective parameters in the atomization process. Using response surfaces obtained by two factorial design techniques, the experimental design was applied for three effective parameters namely ashing temperature, atomizing temperature and modifier concentration as effective parameters on the atomization of Pt. The in situ digestions of serum samples, as well as the separation of the ultra-traces of Pt from concomitant in these samples were performed by using the in situ electrodeposition (ED) technique prior to the measurement by ETAAS. Six plasma samples of a patient who was administered parenteral cisplatin were analyzed using the proposed ED-ETAAS technique. The results showed the pharmacokinetic parameters of cisplatin in serum in accordance to the well-established data. A relatively good reproducibility %RSD=2.44, low limit of detection LOD=2.54 microg/L and promising characteristic mass m(o)=91.30 pg were obtained using this technique. Copyright 2010 Elsevier B.V. All rights reserved.

  6. A new supramolecular based liquid solid microextraction method for preconcentration and determination of trace bismuth in human blood serum and hair samples by electrothermal atomic absorption spectrometry.

    Science.gov (United States)

    Kahe, Hadi; Chamsaz, Mahmoud

    2016-11-01

    A simple and reliable supramolecule-aggregated liquid solid microextraction method is described for preconcentration and determination of trace amounts of bismuth in water as well as human blood serum and hair samples. Catanionic microstructures of cetyltrimethylammonium bromide (CTAB) and sodium dodecyl sulfate (SDS) surfactants, dissolved in deionized water/propanol, are used as a green solvent to extract bismuth (III)-diethyldithiocarbamate complexes by dispersive microextraction methodology. The extracted solid phase is easily removed and dissolved in 50 μL propanol for subsequent measurement by electrothermal atomic absorption spectrometry (ET-AAS). The procedure benefits the merits of supramolecule aggregates' properties and dispersive microextraction technique using water as the main component of disperser solvent, leading to direct interaction with analyte. Phase separation behavior of extraction solvent and different parameters influencing the extraction efficiency of bismuth ion such as salt concentration, pH, centrifugation time, amount of chelating agent, SDS:CTAB mole ratio, and solvent amounts were thoroughly optimized. Under the optimal experimental conditions, the calibration curve was linear in the range of 0.3-6 μg L-1 Bi (III) with a limit of detection (LOD) of 0.16 μg L-1 (S/N = 3). The relative standard deviations (RSD) of determination were obtained to be 5.1 and 6.2 % for 1 and 3 μg L-1 of Bi (III), respectively. The developed method was successfully applied as a sensitive and accurate technique for determination of bismuth ion in human blood serum, hair samples, and a certified reference material.

  7. Hollow fiber liquid phase microextraction combined with electrothermal atomic absorption spectrometry for the speciation of arsenic (III) and arsenic (V) in fresh waters and human hair extracts

    Energy Technology Data Exchange (ETDEWEB)

    Jiang Hongmei [Department of Chemistry, Wuhan University, Wuhan 430072 (China); Hu Bin [Department of Chemistry, Wuhan University, Wuhan 430072 (China)], E-mail: binhu@whu.edu.cn; Chen Beibei; Xia Linbo [Department of Chemistry, Wuhan University, Wuhan 430072 (China)

    2009-02-16

    A new method of hollow fiber liquid phase microextraction (HF-LPME) using ammonium pyrrolidine dithiocarbamate (APDC) as extractant combined with electrothermal atomic absorption spectrometry (ETAAS) using Pd as permanent modifier has been described for the speciation of As(III) and As(V). In a pH range of 3.0-4.0, the complex of As(III)-APDC complex can be extracted using toluene as the extraction solvent leaving As(V) in the aqueous layer. The post extraction organic phase was directly injected into ETAAS for the determination of As(III). To determine total arsenic in the samples, first As(V) was reduced to As(III) by L-cysteine, and then a microextraction method was performed prior to the determination of total arsenic. As(V) assay was based on subtracting As(III) form the total arsenic. All parameters, such as pH of solution, type of organic solvent, the amount of APDC, stirring rate and extraction time, affecting the separation of As(III) from As(V) and the extraction efficiency of As(III) were investigated, and the optimized extraction conditions were established. Under optimized conditions, a detection limit of 0.12 ng mL{sup -1} with enrichment factor of 78 was achieved. The relative standard deviation (R.S.D.) of the method for five replicate determinations of 5 ng mL{sup -1} As(III) was 8%. The developed method was applied to the speciation of As(III) and As(V) in fresh water and human hair extracts, and the recoveries for the spiked samples are 86-109%. In order to validate the developed method, three certified reference materials such as GBW07601 human hair, BW3209 and BW3210 environmental water were analyzed, and the results obtained were in good agreement with the certified values provided.

  8. Impact of carriers in oral absorption

    DEFF Research Database (Denmark)

    Gram, Luise Kvisgaard; Rist, Gerda Marie; Lennernäs, Hans

    2009-01-01

    Carriers may mediate the permeation across enterocytes for drug substances being organic anions. Carrier mediated permeation for the organic anions estrone-3-sulfate (ES) and glipizide across Caco-2 cells were investigated kinetically, and interactions on involved carriers evaluated. Initial...

  9. Endocytosis-inducer adhesins produced by enteropathogenic serogroups of Escherichia coli participate on bacterial attachment to infant enterocytes

    Directory of Open Access Journals (Sweden)

    João Ramos Costa Andrade

    1987-03-01

    Full Text Available Enteropathogenic E. coli (EPEC infection of Hep-2 cells preoceeds through bacterial attachment to cell surface and internalization of adhered bacteria. EPEC attachment is a prerequisite for cell infection and is mediated by adhesins that recognize carbohydrate-containing receptors on cell membrane. Such endocytosis-inducer adhesins (EIA also promote EPEC binding to infant enterocytes, suggesting that EIA may have an important role on EPEC gastroenteritis.A infecção de células Hep-2 por E. coli enteropatogênicas (ECEP implica na aderência bacteriana e posterior interiorização dos microrganismos aderidos por um mecanismo de endocitose. A aderência das ECEP é pré-requisito para a infecção e é mediada por adesinas que reconhecem receptores inibidos por certas oses na membrana celular. Tais "adesinas indutoras da endocitose" (AIE também promovem a ligação bacteriana a enterócitos obtidos do intestino delgado de lactente, sugerindo que as AIE possam desempenhar algum papel nas diarréias causadas por ECEP.

  10. Comparative genomics reveals that a fish pathogenic bacterium Edwardsiella tarda has acquired the locus of enterocyte effacement (LEE) through horizontal gene transfer.

    Science.gov (United States)

    Nakamura, Yoji; Takano, Tomokazu; Yasuike, Motoshige; Sakai, Takamitsu; Matsuyama, Tomomasa; Sano, Motohiko

    2013-09-22

    Edwardsiella tarda is an enterobacterium which causes edwardsiellosis, a fatal disease of cultured fishes such as red sea bream, eel, and flounder. Preventing the occurrence of E. tarda infection has thus been an important issue in aquaculture. E. tarda has been isolated from other animals and from many environments; however, the relationship between the genotype and evolutionary process of this pathogen is not fully understood. To clarify this relationship, we sequenced and compared the genomes of pathogenic and non-pathogenic E. tarda strains isolated from fish, human, and eel pond using next-generation sequencing technology. Eight strains of E. tarda were sequenced with high accuracy (>99.9%) with coverages from 50- to 400-fold. The obtained reads were mapped to a public reference genome. By comparing single nucleotide and insertion/deletion polymorphisms, we found that an attenuated strain of E. tarda had a loss-of-function mutation in a gene related to the type III secretion system (T3SS), suggesting that this gene is involved in the virulence of E. tarda. A comprehensive gene comparison indicated that fish pathogenic strains possessed a type VI secretion system (T6SS) and pilus assembly genes in addition to the T3SS. Moreover, we found that an E. tarda strain isolated from red sea bream harbored two pathogenicity islands of T3SS and T6SS, which were absent in other strains. In particular, this T3SS was homologous to the locus of enterocyte effacement (LEE) in enteropathogenic and enterohemorrhagic Escherichia coli. Evolutionary analysis suggested that this locus, here named Et-LEE (E. tarda LEE), was introgressed into the E. tarda genome through horizontal transfer. We found significant differences in the presence/absence of virulence-related genes among E. tarda strains, reflecting their evolutionary relationship. In particular, a single genotype previously proposed for fish-pathogenic strains may be further divided into two subgroups. Furthermore, the

  11. Comparison of the gastrointestinal anatomy, physiology, and biochemistry of humans and commonly used laboratory animals.

    Science.gov (United States)

    Kararli, T T

    1995-07-01

    In addition to metabolic differences, the anatomical, physiological, and biochemical differences in the gastrointestinal (G.I.) tract of the human and common laboratory animals can cause significant variation in drug absorption from the oral route. Among the physiological factors, pH, bile, pancreatic juice, and mucus and fluid volume and content can modify dissolution rates, solubility, transit times, and membrane transport of drug molecules. The microbial content of the G.I. tract can significantly affect the reductive metabolism and enterohepatic circulation of drugs and colonic delivery of formulations. The transit time of dosage forms can be significantly different between species due to different dimensions and propulsive activities of the G.I. tract. The lipid/protein composition of the enterocyte membrane along the G.I. tract can alter binding and passive, active, and carrier-mediated transport of drugs. The location and number of Peyer's patches can also be important in the absorption of large molecules and particulate matter. While small animals, rats, mice, guinea pigs, and rabbits, are most suitable for determining the mechanism of drug absorption and bioavailability values from powder or solution formulations, larger animals, dogs, pigs, and monkeys, are used to assess absorption from formulations. The understanding of physiological, anatomical, and biochemical differences between the G.I. tracts of different animal species can lead to the selection of the correct animal model to mimic the bioavailability of compounds in the human. This article reviews the anatomical, physiological, and biochemical differences between the G.I. tracts of humans and commonly used laboratory animals.

  12. Establishment and Characterization of a Novel Caco-2 Subclone with a Similar Low Expression Level of Human Carboxylesterase 1 to Human Small Intestine.

    Science.gov (United States)

    Ohura, Kayoko; Nishiyama, Hikaru; Saco, Saori; Kurokawa, Keisuke; Imai, Teruko

    2016-12-01

    Caco-2 cells predominantly express human carboxylesterase 1 (hCE1), unlike the human intestine that predominantly expresses human carboxylesterase 2 (hCE2). Transport experiments using Caco-2 cell monolayers often lead to misestimation of the intestinal absorption of prodrugs because of this difference, as prodrugs designed to increase the bioavailability of parent drugs are made to be resistant to hCE2 in the intestine, so that they can be hydrolyzed by hCE1 in the liver. In the present study, we tried to establish a new Caco-2 subclone, with a similar pattern of carboxylase expression to human intestine, to enable a more accurate estimation of the intestinal absorption of prodrugs. Although no subclone could be identified with high expression levels of only hCE2, two subclones, #45 and #78, with extremely low expression levels of hCE1 were subcloned from parental Caco-2 cells by the limiting dilution technique. Unfortunately, subclone #45 did not form enterocyte-like cell monolayers due to low expression of claudins and β-actin. However, subclone #78 formed polarized cell monolayers over 4 weeks and showed similar paracellular and transcellular transport properties to parental Caco-2 cell monolayers. In addition, the intestinal transport of oseltamivir, a hCE1 substrate, could be evaluated in subclone #78 cell monolayers, including P-glycoprotein-mediated efflux under nonhydrolysis conditions, unlike parental Caco-2 cells. Consequently, it is proposed that subclone #78 may provide a more effective system in which to evaluate the intestinal absorption of prodrugs that are intended to be hydrolyzed by hCE1. Copyright © 2016 by The American Society for Pharmacology and Experimental Therapeutics.

  13. X-ray absorption spectroscopic characterization of the diferric-peroxo intermediate of human deoxyhypusine hydroxylase in the presence of its substrate eIF5a.

    Science.gov (United States)

    Jasniewski, Andrew J; Engstrom, Lisa M; Vu, Van V; Park, Myung Hee; Que, Lawrence

    2016-09-01

    Human deoxyhypusine hydroxylase (hDOHH) is an enzyme that is involved in the critical post-translational modification of the eukaryotic translation initiation factor 5A (eIF5A). Following the conversion of a lysine residue on eIF5A to deoxyhypusine (Dhp) by deoxyhypusine synthase, hDOHH hydroxylates Dhp to yield the unusual amino acid residue hypusine (Hpu), a modification that is essential for eIF5A to promote peptide synthesis at the ribosome, among other functions. Purification of hDOHH overexpressed in E. coli affords enzyme that is blue in color, a feature that has been associated with the presence of a peroxo-bridged diiron(III) active site. To gain further insight into the nature of the diiron site and how it may change as hDOHH goes through the catalytic cycle, we have conducted X-ray absorption spectroscopic studies of hDOHH on five samples that represent different species along its reaction pathway. Structural analysis of each species has been carried out, starting with the reduced diferrous state, proceeding through its O2 adduct, and ending with a diferric decay product. Our results show that the Fe⋯Fe distances found for the five samples fall within a narrow range of 3.4-3.5 Å, suggesting that hDOHH has a fairly constrained active site. This pattern differs significantly from what has been associated with canonical dioxygen activating nonheme diiron enzymes, such as soluble methane monooxygenase and Class 1A ribonucleotide reductases, for which the Fe⋯Fe distance can change by as much as 1 Å during the redox cycle. These results suggest that the O2 activation mechanism for hDOHH deviates somewhat from that associated with the canonical nonheme diiron enzymes, opening the door to new mechanistic possibilities for this intriguing family of enzymes.

  14. Analysis of in situ electric field and specific absorption rate in human models for wireless power transfer system with induction coupling.

    Science.gov (United States)

    Sunohara, Tetsu; Hirata, Akimasa; Laakso, Ilkka; Onishi, Teruo

    2014-07-21

    This study investigates the specific absorption rate (SAR) and the in situ electric field in anatomically based human models for the magnetic field from an inductive wireless power transfer system developed on the basis of the specifications of the wireless power consortium. The transfer system consists of two induction coils covered by magnetic sheets. Both the waiting and charging conditions are considered. The transfer frequency considered in this study is 140 kHz, which is within the range where the magneto-quasi-static approximation is valid. The SAR and in situ electric field in the chest and arm of the models are calculated by numerically solving the scalar potential finite difference equation. The electromagnetic modelling of the coils in the wireless power transfer system is verified by comparing the computed and measured magnetic field distributions. The results indicate that the peak value of the SAR averaged over a 10 g of tissue and that of the in situ electric field are 72 nW kg(-1) and 91 mV m(-1) for a transmitted power of 1 W, Consequently, the maximum allowable transmitted powers satisfying the exposure limits of the SAR (2 W kg(-1)) and the in situ electric field (18.9 V m(-1)) are found to be 28 MW and 43 kW. The computational results show that the in situ electric field in the chest is the most restrictive factor when compliance with the wireless power transfer system is evaluated according to international guidelines.

  15. Fatty acid transport protein 4 is dispensable for intestinal lipid absorption in mice.

    Science.gov (United States)

    Shim, Jien; Moulson, Casey L; Newberry, Elizabeth P; Lin, Meei-Hua; Xie, Yan; Kennedy, Susan M; Miner, Jeffrey H; Davidson, Nicholas O

    2009-03-01

    FA transport protein 4 (FATP4), one member of a multigene family of FA transporters, was proposed as a major FA transporter in intestinal lipid absorption. Due to the fact that Fatp4(-/-) mice die because of a perinatal skin defect, we rescued the skin phenotype using an FATP4 transgene driven by a keratinocyte-specific promoter (Fatp4(-/-);Ivl-Fatp4(tg/+) mice) to elucidate the role of intestinal FATP4 in dietary lipid absorption. Fatp4(-/-);Ivl-Fatp4(tg/+) mice and wild-type littermates displayed indistinguishable food consumption, growth, and weight gain on either low or high fat (Western) diets, with no differences in intestinal triglyceride (TG) absorption or fecal fat losses. Cholesterol absorption and intestinal TG absorption kinetics were indistinguishable between the genotypes, although Western diet fed Fatp4(-/-);Ivl-Fatp4(tg/+) mice showed a significant increase in enterocyte TG and FA content. There was no compensatory upregulation of other FATP family members or any other FA or cholesterol transporters in Fatp4(-/-);Ivl-Fatp4(tg/+) mice. Furthermore, although serum cholesterol levels were lower in Fatp4(-/-);Ivl-Fatp4(tg/+) mice, there was no difference in hepatic VLDL secretion in-vivo or in hepatic lipid content on either a chow or Western diet. Taken together, our studies find no evidence for a physiological role of intestinal FATP4 in dietary lipid absorption in mice.

  16. Iron absorption from intrinsically-labeled lentils

    Science.gov (United States)

    Low iron (Fe) absorption from important staple foods may contribute to Fe deficiency in developing countries. To date, there are few studies examining the Fe bioavailability of pulse crops as commonly prepared and consumed by humans. The objectives of this study were to characterize the Fe absorpt...

  17. Intestinal absorption of triglyceride and cholesterol. Dietary and pharmacological inhibition to reduce cardiovascular risk.

    Science.gov (United States)

    Ros, E

    2000-08-01

    Triglycerides and cholesterol are important biological lipids, and their excessive intake in the diet is relevant to the development of two prevalent cardiovascular risk factors, obesity and hypercholesterolemia. Because most lipids are essentially water-insoluble molecules, their transport within and absorption from the aqueous medium of intestinal contents is rather complex. This takes place in a series of orderly and interrelated steps, including emulsification, hydrolysis by specific esterases, micellar transport, mucosal absorption, re-synthesis of parent molecules in enterocytes, and assembly with apolipoproteins and other molecules to form chylomicrons, the secretory product of intestinal cells. Many of these processes, however, are not well characterized at the molecular level. While in health the intestinal absorption of triglycerides is very efficient, the same does not apply to cholesterol absorption. Besides being generally inefficient, cholesterol absorption is highly variable, with a between-subject variability that depends in part on genetic factors and an intra-individual variability, which may be modulated by physiological and dietary conditions. All of the sequential steps in intestinal lipid absorption can be interfered with by dietary components or drugs and thus are potential therapeutic targets for inducing a controlled malabsorption of triglyceride, useful in the treatment of obesity, or for rendering cholesterol absorption even more inefficient in an attempt to lower blood cholesterol levels. Nevertheless, intestinally derived cholesterol available to the liver exerts complex feedback regulation on whole-body cholesterol homeostasis that limits the efficacy of cholesterol absorption inhibitors to lower blood cholesterol. This review focuses first on present knowledge of the physiology of intestinal fat absorption, necessary to understand the ways to manipulate it in order to obtain the desired effects on dietary triglyceride and cholesterol

  18. D-xylose absorption

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/003606.htm D-xylose absorption To use the sharing features on this page, please enable JavaScript. D-xylose absorption is a laboratory test to determine ...

  19. The effect of exercise on the absorption of inhaled human insulin via the AERx(R) iDMS in people with type 1 diabetes

    DEFF Research Database (Denmark)

    Petersen, Astrid Heide; Kohler, G; Korsatko, S

    2007-01-01

    OBJECTIVE - This study investigated the effect of moderate exercise on the absorption of inhaled insulin via the AERx(R) insulin Diabetes Management System (iDMS). RESEARCH DESIGN AND METHODS - In this randomized, open-label, 4-period cross-over, glucose clamp study 23 non-smoking subjects.......02), compared to NOEX. CONCLUSION - Thirty minutes of moderate exercise led to unchanged or decreased absorption of inhaled insulin via AERx(R) iDMS, and faster C(max) for early exercise. Thus, patients using AERx(R) iDMS can adjust insulin dose as usually independent of time of exercise, but should be aware...

  20. Cinnamon extract attenuates TNF-alpha-induced intestinal lipoprotein ApoB48 overproduction by regulating inflammatory, insulin, and lipoprotein pathways in enterocytes.

    Science.gov (United States)

    Qin, B; Dawson, H; Polansky, M M; Anderson, R A

    2009-07-01

    We have previously reported that the obesity-associated proinflammatory cytokine, TNF-alpha, stimulates the overproduction of intestinal apolipoprotein (apo) B48 containing lipoproteins. In the current study, we have evaluated whether a water-soluble cinnamon extract [CE (Cinnulin PF)] attenuates the dyslipidemia induced by TNF-alpha in Triton WR-1339 treated hamsters, and whether CE inhibits the oversecrection of apoB48-induced by TNF-alpha in enterocytes in a 35S labeling study. In vivo, oral treatment of Cinnulin PF (50 mg per kg BW), inhibited the postprandial overproduction of apoB48-containing lipoproteins and serum triglyceride levels. In ex vivo 35S labeling studies, CE (10 and 20 microg/ml) inhibited the oversecretion of apoB48 induced by TNF-alpha treated enterocytes into the media. To determine the molecular mechanisms, TNF-alpha treated primary enterocytes isolated from chow-fed hamsters, were incubated with CE (10 microg/ml), and the expression of the inflammatory factor genes, IL1-beta, IL-6, and TNF-alpha, insulin signaling pathway genes, insulin receptor (IR), IRS1, IRS2, phosphatidylinositol 3-kinase (PI3-K), Akt1 and phosphatase and tensin homology (PTEN), as well as the key regulators of lipid metabolism, cluster of differentiation (CD)36, microsomal triglyceride transfer protein (MTTP), and sterol regulatory element binding protein (SREBP)-1c were evaluated. Quantitative real-time PCR assays showed that CE treatment decreased the mRNA expression of IL-1beta, IL-6 and TNF-alpha, improved the mRNA expression of IR, IRS1, IRS2, PI3K and Akt1, inhibited CD36, MTTP, and PTEN, and enhanced the impaired SREBP-1c expression in TNF-alpha treated enterocytes. These data suggest that a water extract of cinnamon reverses TNF-alpha-induced overproduction of intestinal apoB48 by regulating gene expression involving inflammatory, insulin, and lipoprotein signaling pathways. In conclusion, Cinulin PF improves inflammation related intestinal dyslipidemia.

  1. Absorption and Metabolism of Xanthophylls

    Directory of Open Access Journals (Sweden)

    Eiichi Kotake-Nara

    2011-06-01

    Full Text Available Dietary carotenoids, especially xanthophylls, have attracted significant attention because of their characteristic biological activities, including anti-allergic, anti-cancer, and anti-obese actions. Although no less than forty carotenoids are ingested under usual dietary habits, only six carotenoids and their metabolites have been found in human tissues, suggesting selectivity in the intestinal absorption of carotenoids. Recently, facilitated diffusion in addition to simple diffusion has been reported to mediate the intestinal absorption of carotenoids in mammals. The selective absorption of carotenoids may be caused by uptake to the intestinal epithelia by the facilitated diffusion and an unknown excretion to intestinal lumen. It is well known that β-carotene can be metabolized to vitamin A after intestinal absorption of carotenoids, but little is known about the metabolic transformation of non provitamin A xanthophylls. The enzymatic oxidation of the secondary hydroxyl group leading to keto-carotenoids would occur as a common pathway of xanthophyll metabolism in mammals. This paper reviews the absorption and metabolism of xanthophylls by introducing recent advances in this field.

  2. Inhibition of Bifidobacterium Cell Wall 51.74 kDa Adhesin Isolated from Infants Feces Towards Adhesion of Enteric Phatogen E. coli on Enterocyte Balb/C Mice

    Directory of Open Access Journals (Sweden)

    I Sukrama

    2012-01-01

    Full Text Available Objectives: To determine 51.74 kDa adhesin of Bifidobacterium sp cell wall isolated from infants feces as an anti adhesion of E. coli on enterocyte mice. Methods: Randomized Posttest-Only Control Group Design was employed to investigate adherence ability of this adhesin towards E.coli adhesion on mice entherocyte. Results: In this research, it was obtained, that the 51.74 kDa adhesin cell wall of Bifidobacterium sp has an ability to inhibit adhesion of E. coli on mice enterocyte. The ability was increased as an increase of adhsein concentration. Conclusions: that can be drawn from this research is the finding of 51.74 kDa adhesin cell wall of Bifidobacterium sp isolated from infants feces that can inhibit adhseion of E. coli on mice enterocyte. Future work that can be carried out are further researches concerning whether these protein can be applied to inhibit adherence of other pathogen bacteria

  3. Flotillin-2 expression in the human gut: from a cell model to human tissue in health and inflammatory bowel diseases.

    Science.gov (United States)

    Gauss, Annika; Buchholz, Inga; Zahn, Alexandra; Schmitz, Gerd; Stremmel, Wolfgang; Fuellekrug, Joachim; Ehehalt, Robert

    2013-01-01

    The etiopathogenesis of inflammatory bowel diseases (IBD) remains largely unexplained. Flotillins (flotillin-1 and flotillin-2) are ubiquitous proteins which have been linked to inflammation and regeneration. We hypothesized that alterations in the expression of flotillin-2 in enterocytes may be related to the pathogenesis of IBD as a classical example of an inflammatory disorder of mostly unknown origin. Cell and tissue localization of flotillin-2 (and -1) were investigated by immunofluorescent staining in 1. polarized and unpolarized CaCo-2w cells as a model of human enterocytes (native and after TNFα stimulation) and 2. intestinal biopsies from controls, patients with ulcerative colitis (UC) and patients with Crohn's disease (CD). For quantification of flotillin-2, we analyzed its expression in ileal and colonic biopsies from controls, UC patients and CD patients using real-time RT-PCR, Western blot and indirect immunofluorescence. In polarized CaCo-2w cells and human enterocytes in biopsies, flotillins were localized at the basolateral membrane and on subapical vesicles, but not in the apical membrane. Flotillin-2 expression did not differ between UC patients, CD patients and controls. However, it was significantly higher in colonic biopsies compared to ileal biopsies in all groups. By virtue of its abundant expression in enterocytes, flotillin-2 must have an essential function in intestinal physiology, especially in the colon. Yet our data could not link flotillin-2 to the pathogenesis of IBD.

  4. Bacterial-Chromatin Structural Proteins Regulate the Bimodal Expression of the Locus of Enterocyte Effacement (LEE Pathogenicity Island in Enteropathogenic Escherichia coli

    Directory of Open Access Journals (Sweden)

    Hervé Leh

    2017-08-01

    Full Text Available In enteropathogenic Escherichia coli (EPEC, the locus of enterocyte effacement (LEE encodes a type 3 secretion system (T3SS essential for pathogenesis. This pathogenicity island comprises five major operons (LEE1 to LEE5, with the LEE5 operon encoding T3SS effectors involved in the intimate adherence of bacteria to enterocytes. The first operon, LEE1, encodes Ler (LEE-encoded regulator, an H-NS (nucleoid structuring protein paralog that alleviates the LEE H-NS silencing. We observed that the LEE5 and LEE1 promoters present a bimodal expression pattern, depending on environmental stimuli. One key regulator of bimodal LEE1 and LEE5 expression is ler expression, which fluctuates in response to different growth conditions. Under conditions in vitro considered to be equivalent to nonoptimal conditions for virulence, the opposing regulatory effects of H-NS and Ler can lead to the emergence of two bacterial subpopulations. H-NS and Ler share nucleation binding sites in the LEE5 promoter region, but H-NS binding results in local DNA structural modifications distinct from those generated through Ler binding, at least in vitro. Thus, we show how two nucleoid-binding proteins can contribute to the epigenetic regulation of bacterial virulence and lead to opposing bacterial fates. This finding implicates for the first time bacterial-chromatin structural proteins in the bimodal regulation of gene expression.

  5. The Small Regulatory RNA Spot42 Inhibits Indole Biosynthesis to Negatively Regulate the Locus of Enterocyte Effacement of Enteropathogenic Escherichia coli

    Directory of Open Access Journals (Sweden)

    Shantanu Bhatt

    2017-12-01

    Full Text Available The locus of enterocyte effacement is necessary for enteropathogenic Escherichia coli (EPEC to form attaching and effacing (A/E lesions. A/E lesions are characterized by intimate bacterial adherence to intestinal cells and destruction of microvilli, which leads to diarrhea. Therefore, studies interrogating the regulation of the locus of enterocyte effacement (LEE are critical for understanding the molecular epidemiology of EPEC infections and developing interventional strategies. Hitherto, most studies have centered on protein-based regulators, whereas the role of small regulatory RNAs remains underappreciated. Previously, we identified the first sRNAs—MgrR, RyhB, and McaS—that regulate the LEE of EPEC. This study was undertaken to identify additional sRNAs that impact the LEE. Our results suggest that the catabolite-responsive sRNA, Spot42, indirectly controls the LEE by inhibiting synthesis of its inducer, indole. Spot42 base-pairs with the tnaCAB mRNA and presumably destabilizes the transcript, thereby preventing expression of the regulatory and structural proteins that are involved in the import and hydrolysis of tryptophan into indole. The absence of intracellular indole leads to reduced transcription of the LEE1-encoded master transcriptional activator Ler, thereby maintaining the LEE in its silenced state and delaying A/E lesion morphogenesis. Our results highlight the importance of riboregulators that synchronize metabolic and virulence pathways in bacterial infection.

  6. Oleic Acid Uptake Reveals the Rescued Enterocyte Phenotype of Colon Cancer Caco-2 by HT29-MTX Cells in Co-Culture Mode.

    Science.gov (United States)

    Berger, Emmanuelle; Nassra, Merian; Atgié, Claude; Plaisancié, Pascale; Géloën, Alain

    2017-07-20

    Gastrointestinal epithelium is the unique route for nutrients and for many pharmaceuticals to enter the body. The present study aimed to analyze precisely whether co-culture of two colon cancer cell lines, mucus-producing cells HT29-MTX and enterocyte-like Caco-2 cells, ameliorate differentiation into an in vitro intestinal barrier model and the signaling pathways involved. Differentiated Caco-2 cells gene datasets were compared first to intestinal or cancer phenotypes and second to signaling pathway gene datasets. Experimental validations were performed in real-time experiments, immunochemistry, and gene expression analyses on Caco-2 versus co-cultures of Caco-2 and HT29-MTX (10%) cells. Partial maintenance of cancer-cell phenotype in differentiated Caco-2 cells was confirmed and fatty acids merged as potential regulators of cancer signaling pathways. HT29-MTX cells induced morphological changes in Caco-2 cells, slightly increased their proliferation rate and profoundly modified gene transcription of phenotype markers, fatty acid receptors, intracellular transporters, and lipid droplet components as well as functional responses to oleic acid. In vitro, enterocyte phenotype was rescued partially by co-culture of cancer cells with goblet cells and completed through oleic acid interaction with signaling pathways dysregulated in cancer cells.

  7. Retrograde cholesterol transport in the human Caco-2/TC7 cell line: a model to study trans-intestinal cholesterol excretion in atherogenic and diabetic dyslipidemia.

    Science.gov (United States)

    Dugardin, Camille; Briand, Olivier; Touche, Véronique; Schonewille, Marleen; Moreau, François; Le May, Cédric; Groen, Albert K; Staels, Bart; Lestavel, Sophie

    2017-02-01

    The dyslipidemia associated with type 2 diabetes is a major risk factor for the development of atherosclerosis. Trans-intestinal cholesterol excretion (TICE) has recently been shown to contribute, together with the classical hepatobiliary route, to fecal cholesterol excretion and cholesterol homeostasis. The aim of this study was to develop an in vitro cell model to investigate enterocyte-related processes of TICE. Differentiated Caco-2/TC7 cells were grown on transwells and incubated basolaterally (blood side) with human plasma and apically (luminal side) with lipid micelles. Radioactive and fluorescent cholesterol tracers were used to investigate cholesterol uptake at the basolateral membrane, intracellular distribution and apical excretion. Our results show that cholesterol is taken up at the basolateral membrane, accumulates intracellularly as lipid droplets and undergoes a cholesterol acceptor-facilitated and progressive excretion through the apical membrane of enterocytes. The overall process is abolished at 4 °C, suggesting a biologically active phenomenon. Moreover, this trans-enterocytic retrograde cholesterol transport displays some TICE features like modulation by PCSK9 and an ABCB1 inhibitor. Finally, we highlight the involvement of microtubules in the transport of plasma cholesterol from basolateral to apical pole of enterocytes. The human Caco-2/TC7 cell line appears a good in vitro model to investigate the enterocytic molecular mechanisms of TICE, which may help to identify intestinal molecular targets to enhance reverse cholesterol transport and fight against dyslipidemia.

  8. Hypochlorhydria from short-term omeprazole treatment does not inhibit intestinal absorption of calcium, phosphorus, magnesium or zinc from food in humans.

    Science.gov (United States)

    Serfaty-Lacrosniere, C; Wood, R J; Voytko, D; Saltzman, J R; Pedrosa, M; Sepe, T E; Russell, R R

    1995-08-01

    Low gastric pH is generally believed to be an important factor in intestinal mineral absorption. Thus, hypochlorhydria could be an important risk factor for mineral malabsorption and the development of marginal mineral status. We studied whether the hypochlorhydria associated with treatment with the anti-ulcer medication omeprazole, a potent gastric proton pump inhibition, would affect intestinal calcium, phosphorus, magnesium, or zinc absorption from food. Thirteen normal, healthy adults were assigned to either a control group (n = 5) receiving no drug treatment or an omeprazole treatment group (n = 8) to produce increased gastric pH. Omeprazole treatment of normal volunteers resulted in a significant change in postprandial gastric pH (pH 6.4 +/- 0.3 vs. 3.6 +/- 0.5 in control subjects, p hypochlorhydria resulting from short-term omeprazole treatment substantially increases the risk for developing calcium, phosphorus, magnesium, or zinc deficiencies due to mineral malabsorption.

  9. [Study on lead absorption in pumpkin by atomic absorption spectrophotometry].

    Science.gov (United States)

    Li, Zhen-Xia; Sun, Yong-Dong; Chen, Bi-Hua; Li, Xin-Zheng

    2008-07-01

    A study was carried out on the characteristic of lead absorption in pumpkin via atomic absorption spectrophotometer. The results showed that lead absorption amount in pumpkin increased with time, but the absorption rate decreased with time; And the lead absorption amount reached the peak in pH 7. Lead and cadmium have similar characteristic of absorption in pumpkin.

  10. Avocado consumption enhances human postprandial provitamin A absorption and conversion from a novel high-β-carotene tomato sauce and from carrots.

    Science.gov (United States)

    Kopec, Rachel E; Cooperstone, Jessica L; Schweiggert, Ralf M; Young, Gregory S; Harrison, Earl H; Francis, David M; Clinton, Steven K; Schwartz, Steven J

    2014-08-01

    Dietary lipids have been shown to increase bioavailability of provitamin A carotenoids from a single meal, but the effects of dietary lipids on conversion to vitamin A during absorption are essentially unknown. Based on previous animal studies, we hypothesized that the consumption of provitamin A carotenoids with dietary lipid would enhance conversion to vitamin A during absorption compared with the consumption of provitamin A carotenoids alone. Two separate sets of 12 healthy men and women were recruited for 2 randomized, 2-way crossover studies. One meal was served with fresh avocado (Persea americana Mill), cultivated variety Hass (delivering 23 g of lipid), and a second meal was served without avocado. In study 1, the source of provitamin A carotenoids was a tomato sauce made from a novel, high-β-carotene variety of tomatoes (delivering 33.7 mg of β-carotene). In study 2, the source of provitamin A carotenoids was raw carrots (delivering 27.3 mg of β-carotene and 18.7 mg of α-carotene). Postprandial blood samples were taken over 12 h, and provitamin A carotenoids and vitamin A were quantified in triglyceride-rich lipoprotein fractions to determine baseline-corrected area under the concentration-vs.-time curve. Consumption of lipid-rich avocado enhanced the absorption of β-carotene from study 1 by 2.4-fold (P avocado enhanced the efficiency of conversion to vitamin A (as measured by retinyl esters) by 4.6-fold in study 1 (P avocado for maximum absorption and conversion to vitamin A, especially in populations in which vitamin A deficiency is prevalent. This trial was registered at clinicaltrials.gov as NCT01432210. © 2014 American Society for Nutrition.

  11. [Assessment of nutritional status and of intestinal absorption in asymptomatic patients infected with the human immunodeficiency virus (HIV) with and without chronic hepatitis].

    Science.gov (United States)

    Ortega García, M P; Marti Bonmatí, E

    2006-01-01

    To compare nutritional status and intestinal absorption in asymptomatics HIV patients co-infected or not with hepatitis C virus. 15 patients (9 men and 6 women) HIV seropositive in A1-A2 stage were classified in two groups, A were asymptomatics HIV patients and B were asymptomatic HIV patients with chronic hepatitis C. Nutritional status was determined by weight, height, % ideal weight, body mass index, triceps skinfold, midarm muscle circumference, grip dynamometry and body composition measured by bioelectrical impedance. Intestinal absorption was assesses with D-xilosa test in urine collected over 5 hours after fasting ingestion of 5 grams of D-xylosa. Statistical analysis was made with SPSS (v.11.0). Not statistically significative differences were found in the nutritional status between the two groups of patients. Asymptomatics HIV patients with chronic hepatitis C eliminate less D-xylosa in urine than patients without chronic hepatitis C, being this difference statistically significative. Three out of the eight patients (37.5%) of group B presented malabsorption (HIV patients have a good nutritional status, without differences between patients co-infected or not with hepatitis C virus. Intestinal absorption is altered in patients co-infected and this should be considered because of its potential clinical consequences.

  12. Avocado Consumption Enhances Human Postprandial Provitamin A Absorption and Conversion from a Novel High–β-Carotene Tomato Sauce and from Carrots12

    Science.gov (United States)

    Kopec, Rachel E.; Cooperstone, Jessica L.; Schweiggert, Ralf M.; Young, Gregory S.; Harrison, Earl H.; Francis, David M.; Clinton, Steven K.; Schwartz, Steven J.

    2014-01-01

    Dietary lipids have been shown to increase bioavailability of provitamin A carotenoids from a single meal, but the effects of dietary lipids on conversion to vitamin A during absorption are essentially unknown. Based on previous animal studies, we hypothesized that the consumption of provitamin A carotenoids with dietary lipid would enhance conversion to vitamin A during absorption compared with the consumption of provitamin A carotenoids alone. Two separate sets of 12 healthy men and women were recruited for 2 randomized, 2-way crossover studies. One meal was served with fresh avocado (Persea americana Mill), cultivated variety Hass (delivering 23 g of lipid), and a second meal was served without avocado. In study 1, the source of provitamin A carotenoids was a tomato sauce made from a novel, high–β-carotene variety of tomatoes (delivering 33.7 mg of β-carotene). In study 2, the source of provitamin A carotenoids was raw carrots (delivering 27.3 mg of β-carotene and 18.7 mg of α-carotene). Postprandial blood samples were taken over 12 h, and provitamin A carotenoids and vitamin A were quantified in triglyceride-rich lipoprotein fractions to determine baseline-corrected area under the concentration-vs.-time curve. Consumption of lipid-rich avocado enhanced the absorption of β-carotene from study 1 by 2.4-fold (P < 0.0001). In study 2, the absorption of β-carotene and α-carotene increased by 6.6- and 4.8-fold, respectively (P < 0.0001 for both). Most notably, consumption of avocado enhanced the efficiency of conversion to vitamin A (as measured by retinyl esters) by 4.6-fold in study 1 (P < 0.0001) and 12.6-fold in study 2 (P = 0.0013). These observations highlight the importance of provitamin A carotenoid consumption with a lipid-rich food such as avocado for maximum absorption and conversion to vitamin A, especially in populations in which vitamin A deficiency is prevalent. This trial was registered at clinicaltrials.gov as NCT01432210. PMID:24899156

  13. Absorption and metabolism of the absorption enhancer didecanoylphosphatidylcholine in rabbit nasal epithelium in vivo

    DEFF Research Database (Denmark)

    Vermehren, C.; Johansen, P.B.; Hansen, Harald S.

    1997-01-01

    The absorption enhancer, didecanoylphosphatidylcholine (DDPC), improves the nasal absorption of human growth hormone in rabbits. We elucidated the uptake and the metabolism of 1,2-di[1-C]decanoyl-L-3-phosphatidylcholine and 1,2-didecanoyl-L-3-phosphatidyl[N-methyl-H]choline in rabbit nasal mucosa...

  14. Toxicological effects of pet food ingredients on canine bone marrow-derived mesenchymal stem cells and enterocyte-like cells.

    Science.gov (United States)

    Ortega, M T; Jeffery, B; Riviere, J E; Monteiro-Riviere, N A

    2016-02-01

    We developed an in vitro method to assess pet food ingredients safety. Canine bone marrow-derived mesenchymal stem cells (BMSC) were differentiated into enterocyte-like cells (ELC) to assess toxicity in cells representing similar patterns of exposure in vivo. The toxicological profile of clove leave oil, eugenol, guanosine monophosphate (GMP), GMP + inosine monophosphate, sorbose, ginger root extract, cinnamon bark oil, cinnamaldehyde, thyme oil, thymol and citric acid was assessed in BMSC and ELC. The LC50 for GMP + inosine monophosphate was 59.42 ± 0.90 and 56.7 ± 3.5 mg ml(-1) for BMSC and ELC; 56.84 ± 0.95 and 53.66 ± 1.36 mg ml(-1) for GMP; 0.02 ± 0.001 and 1.25 ± 0.47 mg ml(-1) for citric acid; 0.077 ± 0.002 and 0.037 ± 0.01 mg ml(-1) for cinnamaldehyde; 0.002 ± 0.0001 and 0.002 ± 0.0008 mg ml(-1) for thymol; 0.080 ± 0.003 and 0.059 ± 0.001 mg ml(-1) for thyme oil; 0.111 ± 0.002 and 0.054 ± 0.01 mg ml(-1) for cinnamon bark oil; 0.119 ± 0.0004 and 0.099 ± 0.011 mg ml(-1) for clove leave oil; 0.04 ± 0.001 and 0.028 ± 0.002 mg ml(-1) for eugenol; 2.80 ± 0.11 and 1.75 ± 0.51 mg ml(-1) for ginger root extract; > 200 and 116.78 ± 7.35 mg ml(-1) for sorbose. Lemon grass oil was evaluated at 0.003-0.9 in BMSC and .03-0.9 mg ml(-1) in ELC and its mechanistic effect was investigated. The gene toxicology studies showed regulation of 61% genes in CYP450 pathway, 37% in cholestasis and 33% in immunotoxicity pathways for BMSC. For ELC, 80% for heat shock response, 69% for beta-oxidation and 65% for mitochondrial energy metabolism. In conclusion, these studies provide a baseline against which differential toxicity of dietary feed ingredients can be assessed in vitro for direct effects on canine cells and demonstrate differential toxicity in differentiated cells that represent gastrointestinal epithelial cells

  15. In overweight and obese women, dietary iron absorption is reduced and the enhancement of iron absorption by ascorbic acid is one-half that in normal-weight women.

    Science.gov (United States)

    Cepeda-Lopez, Ana C; Melse-Boonstra, Alida; Zimmermann, Michael B; Herter-Aeberli, Isabelle

    2015-12-01

    Iron deficiency is common in overweight and obese individuals. This deficiency may be due to adiposity-related inflammation that increases serum hepcidin and decreases dietary iron absorption. Because hepcidin reduces iron efflux from the basolateral enterocyte, it is uncertain whether luminal enhancers of dietary iron absorption such as ascorbic acid can be effective in overweight and obese individuals. In this study, we compared iron absorption from a meal with ascorbic acid (+AA) and a meal without ascorbic acid (-AA) in women in a normal-weight group (NW) with those in overweight and obese groups combined (OW/OB). Healthy, nonanemic women [n = 62; BMI (in kg/m(2)): 18.5-39.9] consumed a stable-isotope-labeled wheat-based test meal -AA and a wheat-based test meal +AA (31.4 mg ascorbic acid). We measured iron absorption and body composition with the use of dual-energy X-ray absorptiometry, blood volume with the use of a carbon monoxide (CO)-rebreathing method, iron status, inflammation, and serum hepcidin. Inflammatory biomarkers (all P ascorbic acid on iron absorption is one-half of that in normal-weight women. Recommending higher intakes of ascorbic acid (or other luminal enhancers of iron absorption) in obese individuals to improve iron status may have a limited effect. This trial was registered at clinicaltrials.gov as NCT01884506. © 2015 American Society for Nutrition.

  16. Hepcidin in human iron disorders: diagnostic implications.

    Science.gov (United States)

    Kroot, Joyce J C; Tjalsma, Harold; Fleming, Robert E; Swinkels, Dorine W

    2011-12-01

    The peptide hormone hepcidin plays a central role in regulating dietary iron absorption and body iron distribution. Many human diseases are associated with alterations in hepcidin concentrations. The measurement of hepcidin in biological fluids is therefore a promising tool in the diagnosis and management of medical conditions in which iron metabolism is affected. We describe hepcidin structure, kinetics, function, and regulation. We moreover explore the therapeutic potential for modulating hepcidin expression and the diagnostic potential for hepcidin measurements in clinical practice. Cell-culture, animal, and human studies have shown that hepcidin is predominantly synthesized by hepatocytes, where its expression is regulated by body iron status, erythropoietic activity, oxygen tension, and inflammatory cytokines. Hepcidin lowers serum iron concentrations by counteracting the function of ferroportin, a major cellular iron exporter present in the membrane of macrophages, hepatocytes, and the basolateral site of enterocytes. Hepcidin is detected in biologic fluids as a 25 amino acid isoform, hepcidin-25, and 2 smaller forms, i.e., hepcidin-22 and -20; however, only hepcidin-25 has been shown to participate in the regulation of iron metabolism. Reliable assays to measure hepcidin in blood and urine by use of immunochemical and mass spectrometry methods have been developed. Results of proof-of-principle studies have highlighted hepcidin as a promising diagnostic tool and therapeutic target for iron disorders. However, before hepcidin measurements can be used in routine clinical practice, efforts will be required to assess the relevance of hepcidin isoform measurements, to harmonize the different assays, to define clinical decision limits, and to increase assay availability for clinical laboratories.

  17. Membrane Gas Absorption

    NARCIS (Netherlands)

    Jansen, A.E.; Klaassen, R.; Feron, P.H.M.

    1995-01-01

    Membrane gas absorption processes are absorption processes utilising hollow fibre membranes as contacting media for gas and liquid flows. The principle of operation and engineering aspects are discussed, followed by discussion of a number of typical applications. Benefits in terms of operation,

  18. Nutrition and magnesium absorption

    NARCIS (Netherlands)

    Brink, E.J.

    1992-01-01

    The influence of various nutrients present in dairy products and soybean-based products on absorption of magnesium has been investigated. The studies demonstrate that soybean protein versus casein lowers apparent magnesium absorption in rats through its phytate component. However, true

  19. Solar absorption surface panel

    Science.gov (United States)

    Santala, Teuvo J.

    1978-01-01

    A composite metal of aluminum and nickel is used to form an economical solar absorption surface for a collector plate wherein an intermetallic compound of the aluminum and nickel provides a surface morphology with high absorptance and relatively low infrared emittance along with good durability.

  20. Investigation of three doses of oral insulin-like growth factor-I on jejunal lactase phlorizin hydrolase activity and gene expression and enterocyte proliferation and migration in piglets.

    Science.gov (United States)

    Houle, V M; Park, Y K; Laswell, S C; Freund, G G; Dudley, M A; Donovan, S M

    2000-10-01

    In a previous study, oral IGF-I at 65 nM increased lactase phlorizin hydrolase (LPH) activity and villus height in piglets, however, the mechanisms were unknown. Herein, the response to a range of doses of IGF-I was investigated and we hypothesized that LPH and villus height would respond to oral IGF-I in a dose-dependent manner. Two 14-d experiments were conducted using cesarean-derived piglets. In experiment 1, piglets (n = 28) were fed formula containing 0, 33, 65, or 131 nmol/L (0, 0.25, 0.5, or 1.0 mg/L) recombinant human IGF-I. In experiment 2, 5'-bromodeoxyuridine was administered to piglets fed formula alone (n = 4) or containing 131 nmol/L IGF-I (n = 4). IGF-I did not affect body weight gain or intestinal weight or length. Jejunal villus height and LPH activity were significantly greater in piglets fed 131 nmol IGF-I/L than control piglets. Villus height and lactase activity in piglets fed the 33 and 65 nmol/L IGF-I doses were similar and intermediate between control and 131 nmol IGF-I/L. Jejunal mRNA expression and LPH polypeptide abundance were investigated in piglets receiving 0 or 131 nmol/L IGF-I. Steady state LPH mRNA abundance was significantly higher (p < 0.05) in IGF-I-treated piglets. The relative abundance of proLPH(h) was not significantly increased (p = 0.06) by IGF-I treatment. Mucosal DNA content and DNA synthesis were greater in piglets receiving 131 nmol IGF-I/L than control, however, enterocyte migration and mucosal protein content were unaffected. Thus, oral IGF-I increased jejunal LPH activity and LPH mRNA abundance and stimulated intestinal cell hyperplasia in normal piglets.

  1. The Genetia, Harbored by the Subtilase-Encoding Pathogenicity Island, Is Involved in the Ability of Locus of Enterocyte Effacement-Negative Shiga Toxin-Producing Escherichia coli Strains To Invade Monolayers of Epithelial Cells.

    Science.gov (United States)

    Bondì, Roslen; Chiani, Paola; Michelacci, Valeria; Minelli, Fabio; Caprioli, Alfredo; Morabito, Stefano

    2017-12-01

    Locus of enterocyte effacement (LEE)-negative Shiga toxin (Stx)-producing Escherichia coli (STEC) strains are human pathogens that lack the LEE locus, a pathogenicity island (PAI) involved in the intimate adhesion of LEE-positive strains to the host gut epithelium. The mechanism used by LEE-negative STEC strains to colonize the host intestinal mucosa is still not clear. The cell invasion determinant tia , previously described in enterotoxigenic E. coli strains, has been identified in LEE-negative STEC strains that possess the subtilase-encoding pathogenicity island (SE-PAI). We evaluated the role of the gene tia , present in these LEE-negative STEC strains, in the invasion of monolayers of cultured cells. We observed that these strains were able to invade Caco-2 and HEp-2 cell monolayers and compared their invasion ability with that of a mutant strain in which the gene tia had been inactivated. Mutation of the gene tia resulted in a strong reduction of the invasive phenotype, and complementation of the tia mutation with a functional copy of the gene restored the invasion activity. Moreover, we show that the gene tia is overexpressed in bacteria actively invading cell monolayers, demonstrating that tia is involved in the ability to invade cultured monolayers of epithelial cells shown by SE-PAI-positive E. coli , including STEC, strains. However, the expression of the tia gene in the E. coli K-12 strain JM109 was not sufficient, in its own right, to confer to this strain the ability to invade cell monolayers, suggesting that at least another factor must be involved in the invasion ability displayed by the SE-PAI-positive strains. Copyright © 2017 American Society for Microbiology.

  2. Intestinal phosphate absorption: influence of vitamin D and non-vitamin D factors.

    Science.gov (United States)

    Lee, D B; Walling, M W; Brautbar, N

    1986-03-01

    The transport of inorganic phosphate (P) was measured in the absence of electrochemical gradients across rat jejunum in vitro. Active P absorption was demonstrated in young, vitamin D-deficient (-D) rats, whereas active P secretion was found in normal, non-vitamin D-deficient adult rats, suggesting regulation of intestinal P transport by age-dependent but vitamin D-independent mechanisms. 1,25-Dihydroxyvitamin D3 [1,25(OH)2D3] stimulated mucosal-to-serosal P flux (Jm----s) without affecting serosal-to-mucosal P flux (Js----m), causing further increases in net P absorption (Jnet) in -D rats and reduction in net P secretion in normal adult rats, confirming a previously described role of this hormone on P absorption. We then examined the effect of increasing extracellular (buffer) P concentration [P] on this 1,25(OH)2D3-stimulated active P absorption in jejunum from -D rats. At [P] of 0.024, 0.24, and 2.4 mM, 1,25(OH)2D3 consistently stimulated Jm----s without affecting Js----m, causing an increment in Jnet. At 7.5 mM [P], however, this Jm----s stimulatory effect of 1,25(OH)2D3 was no longer observed. Moreover, at this [P] the Js----m exceeded Jm----s in both -D and 1,25(OH)2D3-repleted rats, converting the active P absorption into active P secretion in both treatment groups. These observations suggest the participation of local mechanisms, such as the ambient [P] of the transporting enterocytes, in the regulation of intestinal P absorption. Finally, the influence of dietary P deprivation on P absorption was studied in -D rats, with or without either vitamin D3 or 1,25(OH)2D3 repletion.(ABSTRACT TRUNCATED AT 250 WORDS)

  3. Structural analysis of strontium in human teeth treated with surface pre-reacted glass-ionomer filler eluate by using extended X-ray absorption fine structure analysis.

    Science.gov (United States)

    Uo, Motohiro; Wada, Takahiro; Asakura, Kiyotaka

    2017-03-31

    The bioactive effects of strontium released from surface pre-reacted glass-ionomer (S-PRG) fillers may aid in caries prevention. In this study, the local structure of strontium taken up by teeth was estimated by extended X-ray absorption fine structure analysis. Immersing teeth into S-PRG filler eluate increased the strontium content in enamel and dentin by more than 100 times. The local structure of strontium in enamel and dentin stored in distilled water was the same as that in synthetic strontium-containing hydroxyapatite (SrHAP). Moreover, the local structure of strontium in enamel and dentin after immersion in the S-PRG filler eluate was also similar to that of SrHAP. After immersion in the S-PRG filler eluate, strontium was suggested to be incorporated into the hydroxyapatite (HAP) of enamel and dentin at the calcium site in HAP.

  4. Zeeman atomic absorption spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Hadeishi, T.; McLaughlin, R.

    1978-08-01

    The design and development of a Zeeman atomic absorption spectrometer for trace element analysis are described. An instruction manual is included which details the operation, adjustment, and maintenance. Specifications and circuit diagrams are given. (WHK)

  5. Absorption heat pump system

    Science.gov (United States)

    Grossman, Gershon

    1984-01-01

    The efficiency of an absorption heat pump system is improved by conducting liquid from a second stage evaporator thereof to an auxiliary heat exchanger positioned downstream of a primary heat exchanger in the desorber of the system.

  6. Optical absorption measurement system

    Science.gov (United States)

    Draggoo, Vaughn G.; Morton, Richard G.; Sawicki, Richard H.; Bissinger, Horst D.

    1989-01-01

    The system of the present invention contemplates a non-intrusive method for measuring the temperature rise of optical elements under high laser power optical loading to determine the absorption coefficient. The method comprises irradiating the optical element with a high average power laser beam, viewing the optical element with an infrared camera to determine the temperature across the optical element and calculating the absorption of the optical element from the temperature.

  7. Phytases for Improved Iron Absorption

    DEFF Research Database (Denmark)

    Nielsen, Anne Veller Friis; Nyffenegger, Christian; Meyer, Anne S.

    2014-01-01

    Microbial phytases (EC 3.1.3.8) catalyse dephosphorylation of phytic acid, which is the primary storage compound for phosphorous in cereal kernels. The negatively charged phosphates in phytic acid chelate iron (Fe3+) and thus retards iron bioavailability in humans 1. Supplementation of microbial...... phytase can improve iron absorption from cereal-based diets 2. In order for phytase to catalyse iron release in vivo the phytase must be robust to low pH and proteolysis in the gastric ventricle. Our work has compared the robustness of five different microbial phytases, evaluating thermal stability...

  8. Macromolecular absorption and cows' milk allergy.

    OpenAIRE

    Juvonen, P; Jakobsson, I; Lindberg, T.

    1991-01-01

    The absorption of macromolecules was analysed by measuring serum concentrations of human alpha-lactalbumin after feeding human milk, using a competitive radioimmunoassay. The control group consisted of 78 children fed by cows' milk formula; concentrations of alpha-lactalbumin in their serum were low. The median concentrations in the different age groups varied between 7-13 micrograms alpha-lactalbumin/1 serum/1 human milk/kg body weight. Twenty-eight children with cows' milk allergy were stud...

  9. The effect of volatility on percutaneous absorption.

    Science.gov (United States)

    Rouse, Nicole C; Maibach, Howard I

    2016-01-01

    Topically applied chemicals may volatilize, or evaporate, from skin leaving behind a chemical residue with new percutaneous absorptive capabilities. Understanding volatilization of topical medications, such as sunscreens, fragrances, insect repellants, cosmetics and other commonly applied topicals may have implications for their safety and efficacy. A systematic review of English language articles from 1979 to 2014 was performed using key search terms. Articles were evaluated to assess the relationship between volatility and percutaneous absorption. A total of 12 articles were selected and reviewed. Key findings were that absorption is enhanced when coupled with a volatile substance, occlusion prevents evaporation and increases absorption, high ventilation increases volatilization and reduces absorption, and pH of skin has an affect on a chemical's volatility. The articles also brought to light that different methods may have an affect on volatility: different body regions; in vivo vs. in vitro; human vs. Data suggest that volatility is crucial for determining safety and efficacy of cutaneous exposures and therapies. Few articles have been documented reporting evaporation in the context of percutaneous absorption, and of those published, great variability exists in methods. Further investigation of volatility is needed to properly evaluate its role in percutaneous absorption.

  10. Automatic On-line Solid-phase Extraction-Electrothermal Atomic Absorption Spectrometry Exploiting Sequential Injection Analysis for Trace Vanadium, Cadmium and Lead Determination in Human Urine Samples.

    Science.gov (United States)

    Giakisikli, Georgia; Ayala Quezada, Alejandro; Tanaka, Junpei; Anthemidis, Aristidis N; Murakami, Hiroya; Teshima, Norio; Sakai, Tadao

    2015-01-01

    A fully automated sequential injection column preconcentration method for the on-line determination of trace vanadium, cadmium and lead in urine samples was successfully developed, utilizing electrothermal atomic absorption spectrometry (ETAAS). Polyamino-polycarboxylic acid chelating resin (Nobias chelate PA-1) packed into a handmade minicolumn was used as a sorbent material. Effective on-line retention of chelate complexes of analytes was achieved at pH 6.0, while the highest elution effectiveness was observed with 1.0 mol L(-1) HNO3 in the reverse phase. Several analytical parameters, like the sample acidity, concentration and volume of the eluent as well as the loading/elution flow rates, have been studied, regarding the efficiency of the method, providing appropriate conditions for the analysis of real samples. For a 4.5 mL sample volume, the sampling frequency was 27 h(-1). The detection limits were found to be 3.0, 0.06 and 2.0 ng L(-1) for V(V), Cd(II) and Pb(II), respectively, with the relative standard deviations ranging between 1.9 - 3.7%. The accuracy of the proposed method was evaluated by analyzing a certified reference material (Seronorm(TM) trace elements urine) and spiked urine samples.

  11. Application of volumetric absorptive microsampling device for quantification of tacrolimus in human blood as a model drug of high blood cell partition.

    Science.gov (United States)

    Kita, Kenji; Mano, Yuji

    2017-09-05

    Volumetric absorptive microsampling device (VAMS) was evaluated for bioanalysis of tacrolimus, which was used as a model drug with high blood cell partition. Aliquots of blood (ca. 10μL) with different hematocrits and fortified with tacrolimus were wicked up by VAMS and tacrolimus was extracted with a methanol-water mixture (1:1, v/v) via sonication. After chromatography on an AQUITY UPLC HSS T3 column (100×2.1 i.d., mm, 1.8μm), tacrolimus and the internal standard ascomycin, were detected in the positive ion mode with electrospray ionization by monitoring of transitions m/z 826.6→616.4 and m/z 814.6→604.0, respectively. An assay method to quantify tacrolimus from 1 to 250ng/mL in whole blood was qualified by ensuring that linearity, selectivity, intra- and inter-batch reproducibility, and stability were within the acceptance criteria. Consistent and high extraction recovery of tacrolimus was ensured from blood with low- (20%), mid- (45%), and high-hematocrit (65%) levels with minimal matrix effects. Apparent instability at ambient temperature or 4°C possibly due to reduced recovery suggests that tacrolimus in VAMS should be stored at -25°C until assay. Potential reduced recovery over time from VAMS should be taken into consideration in method optimization. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Absorption cooling device. Absorptions-Kuehlvorrichtung

    Energy Technology Data Exchange (ETDEWEB)

    Bourne, J.; Vardi, I.; Kimchi, Y.; Ben-Dror, J.

    1980-03-25

    The invention concerns improvements of absorption refrigerators, where a lithium chloride or lithium bromide/water cycle is used. According to the invention an inner separating or dividing structure between different functional parts of a machine of this type is provided. The structure contains two sections of wall, which are separated from one another by a suitable space, in order to achieve thermal insulation. This air space is provided with an opening in the direction towards the inside of the container and the opening is shielded to prevent the entry of liquids (in liquid or spray form).

  13. Radiation production and absorption in human spacecraft shielding systems under high charge and energy Galactic Cosmic Rays: Material medium, shielding depth, and byproduct aspects

    Science.gov (United States)

    Barthel, Joseph; Sarigul-Klijn, Nesrin

    2018-03-01

    Deep space missions such as the planned 2025 mission to asteroids require spacecraft shields to protect electronics and humans from adverse effects caused by the space radiation environment, primarily Galactic Cosmic Rays. This paper first reviews the theory on how these rays of charged particles interact with matter, and then presents a simulation for a 500 day Mars flyby mission using a deterministic based computer code. High density polyethylene and aluminum shielding materials at a solar minimum are considered. Plots of effective dose with varying shield depth, charged particle flux, and dose in silicon and human tissue behind shielding are presented.

  14. Conformational changes in human serum albumin studied by fluorescence and absorption spectroscopy. Distance measurements as a function of pH and fatty acids

    DEFF Research Database (Denmark)

    Honoré, B; Pedersen, A O

    1989-01-01

    pH- and fatty acid-induced conformational changes in human serum albumin were investigated by fluorescence-energy transfer, determining the distance between Trp-214 and bound bilirubin at 25 degrees C. This distance changes significantly with the pH, being 2.52 +/- 0.01 nm at pH 6, 2.31 +/- 0.04 nm...

  15. Human absorption of a supplement containing purified hydroxytyrosol, a natural antioxidant from olive oil, and evidence for its transient association with low-density lipoproteins.

    Science.gov (United States)

    González-Santiago, Maria; Fonollá, Juristo; Lopez-Huertas, Eduardo

    2010-04-01

    There is growing interest in the health effects of olive oil polyphenols, particularly hydroxytyrosol (HT), for their potential application in the treatment of inflammatory conditions such as cardiovascular disease (CVD). As oxidative modification of low-density lipoproteins (LDL) plays a central role in the development of CVD, natural antioxidants are a main target for the nutraceutical industry. In this study we firstly investigated the absorption of pure hydroxytyrosol (99.5%) administered as a supplement in an aqueous solution (2.5mg/kg BW) in the plasma and urine of healthy volunteers (n=10). Plasma C(max) for HT and homovanillic alcohol (HvOH) were detected at 13.0+/-1.5 and 16.7+/-2.4min, respectively. The HT and HvOH levels were undetectable 2-h after the administration. HT, HvOH, homovanillic acid and 3,4-dihydroxyphenylacetic acid were found as free forms (44%) or as glucuronide (34.4%) or sulphate (21.2%) conjugates in the 24-h urine samples of the subjects. In a second phase of the study, the same amounts of HT were administered to the subjects and the presence of HT in purified plasma lipoproteins was investigated in LDL fractions freshly isolated. 10min after the ingestion of the HT supplement, more than 50% of the total amount detected was present in the LDL-purified fractions and its concentration declined in accordance with its presence in plasma but no changes were found in total antioxidant capacity, malondialdehyde or LDL lag time. These results indicate that pure HT transiently associates with LDL lipoproteins in vivo. Copyright 2009 Elsevier Ltd. All rights reserved.

  16. Central cooling: absorptive chillers

    Energy Technology Data Exchange (ETDEWEB)

    Christian, J.E.

    1977-08-01

    This technology evaluation covers commercially available single-effect, lithium-bromide absorption chillers ranging in nominal cooling capacities of 3 to 1,660 tons and double-effect lithium-bromide chillers from 385 to 1,060 tons. The nominal COP measured at operating conditions of 12 psig input steam for the single-effect machine, 85/sup 0/ entering condenser water, and 44/sup 0/F exiting chilled-water, ranges from 0.6 to 0.65. The nominal COP for the double-effect machine varies from 1.0 to 1.15 with 144 psig entering steam. Data are provided to estimate absorption-chiller performance at off-nominal operating conditions. The part-load performance curves along with cost estimating functions help the system design engineer select absorption equipment for a particular application based on life-cycle costs. Several suggestions are offered which may be useful for interfacing an absorption chiller with the remaining Integrated Community Energy System. The ammonia-water absorption chillers are not considered to be readily available technology for ICES application; therefore, performance and cost data on them are not included in this evaluation.

  17. Effect of food intake and co-administration of placebo self-nanoemulsifying drug delivery systems on the absorption of cinnarizine in healthy human volunteers

    DEFF Research Database (Denmark)

    Christiansen, Martin Lau; Holm, Rene; Abrahamsson, Bertil

    2016-01-01

    the stability issue. The two aims for this present study were therefore; i) to investigate if a nutritional drink, Fresubin Energy®, could induce food effect in humans for the poorly soluble compound cinnarizine; and ii) to investigate if co-administration of a self-nano-emulsifying drug delivery systems...... between dosing. The fed state was induced using a nutritional drink (Fresubin Energy®) and gastric emptying was assessed by administration of paracetamol as a marker. The pharmacokinetic analysis showed that the nutritional drink delayed the uptake and increased the fraction of absorbed cinnarizine......, indicative of a food effect on the compound. This was in agreement with a previous dog study and indicates that the nutritional drink can be used for inducing the same level of food effect in humans. Though not statistically significant, the co-administration of SNEDDS exhibited a tendency towards...

  18. Absorption heat pump system

    Science.gov (United States)

    Grossman, Gershon; Perez-Blanco, Horacio

    1984-01-01

    An improvement in an absorption heat pump cycle is obtained by adding adiabatic absorption and desorption steps to the absorber and desorber of the system. The adiabatic processes make it possible to obtain the highest temperature in the absorber before any heat is removed from it and the lowest temperature in the desorber before heat is added to it, allowing for efficient utilization of the thermodynamic availability of the heat supply stream. The improved system can operate with a larger difference between high and low working fluid concentrations, less circulation losses, and more efficient heat exchange than a conventional system.

  19. Enzymatic synthesis of 2-deoxyglucose-containing maltooligosaccharides for tracing the location of glucose absorption from starch digestion.

    Science.gov (United States)

    Lee, Byung-Hoo; Koh, Dong-Wan; Territo, Paul R; Park, Cheon-Seok; Hamaker, Bruce R; Yoo, Sang-Ho

    2015-11-05

    The ileal brake mechanism which induces a potentially beneficial slower gastric emptying rate and increased satiety is triggered by macronutrients including glucose from glycemic carbohydrates. For optimization of this diet-induced health benefit, there is the need for a way to determine the location of glucose deposition in the small intestine. Labeled 2-deoxyglucose (2-DG) can be used to trace the location of glucose absorption due to its accumulative property in the small intestine enterocytes. However, because pure glucose, or 2-DG, is directly absorbed in the proximal small intestine, we designed 2-DG containing maltooligosaccharides (2-DG-MOs) that can be used with a mild α-glucosidase inhibitor to attain an analytical method for determining location-specific delivery of glucose and its physiological effect. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. Oral Exposure and Absorption of Toxicants

    Science.gov (United States)

    This chapter provides an overview of the toxicokinetics of orally absorbed xenobiotics. This includes a description of the basic anatomy and physiology of the digestive tract most relevant to the absorption process. In addition, differences in anatomy and physiology between human...

  1. Vitamin D inhibits lipopolysaccharide-induced inflammatory response potentially through the Toll-like receptor 4 signalling pathway in the intestine and enterocytes of juvenile Jian carp (Cyprinus carpio var. Jian).

    Science.gov (United States)

    Jiang, Jun; Shi, Dan; Zhou, Xiao-Qiu; Yin, Long; Feng, Lin; Jiang, Wei-Dan; Liu, Yang; Tang, Ling; Wu, Pei; Zhao, Ye

    2015-11-28

    The present study was conducted to investigate the anti-inflammatory effect of vitamin D both in juvenile Jian carp (Cyprinus carpio var. Jian) in vivo and in enterocytes in vitro. In primary enterocytes, exposure to 10 mg lipopolysaccharide (LPS)/l increased lactate dehydrogenase activity in the culture medium (P<0·05) and resulted in a significant loss of cell viability (P<0·05). LPS exposure increased (P<0·05) the mRNA expression of pro-inflammatory cytokines (TNF-α, IL-1β, IL-6 and IL-8), which was decreased by pre-treatment with 1,25-dihydroxyvitamin D (1,25D3) in a dose-dependent manner (P<0·05). Further results showed that pre-treatment with 1,25D3 down-regulated Toll-like receptor 4 (TLR4), myeloid differentiation primary response gene 88 (Myd88) and NF-κB p65 mRNA expression (P<0·05), suggesting potential mechanisms against LPS-induced inflammatory response. In vivo, intraperitoneal injection of LPS significantly increased TNF-α, IL-1β, IL-6 and IL-8 mRNA expression in the intestine of carp (P<0·05). Pre-treatment of fish with vitamin D3 protected the fish intestine from the LPS-induced increase of TNF-α, IL-1β, IL-6 and IL-8 mainly by downregulating TLR4, Myd88 and NF-κB p65 mRNA expression (P<0·05). These observations suggest that vitamin D could inhibit LPS-induced inflammatory response in juvenile Jian carp in vivo and in enterocytes in vitro. The anti-inflammatory effect of vitamin D is mediated at least in part by TLR4-Myd88 signalling pathways in the intestine and enterocytes of juvenile Jian carp.

  2. MNC knowledge transfer, subsidiary absorptive capacity and HRM

    OpenAIRE

    Minbaeva, Dana; Pedersen, Torben; Bjoerkman, Ingmar; Carl F Fey; Park, H J

    2014-01-01

    Based on a sample of 169 subsidiaries of multinational corporations (MNCs) operating in the USA, Russia, and Finland, this paper investigates the relationship between MNC subsidiary human resource management (HRM) practices, absorptive capacity, and knowledge transfer. First, we examine the relationship between the application of specific HRM practices and the level of the absorptive capacity. Second, we suggest that absorptive capacity should be conceptualized as being comprised of both empl...

  3. Visual Absorption Capability

    Science.gov (United States)

    Lee Anderson; Jerry Mosier; Geoffrey Chandler

    1979-01-01

    Visual absorption capability (VAC) is a tool to assess a landscape's susceptibility to visual change caused by man's activities. This paper explores different descriptive approaches to VAC and addresses in depth the development of the VAC process used on the Klamath National Forest. Four biophysical factors were selected to assess VAC for the lands within the...

  4. Chemical Absorption Materials

    DEFF Research Database (Denmark)

    Thomsen, Kaj

    2011-01-01

    Chemical absorption materials that potentially can be used for post combustion carbon dioxide capture are discussed. They fall into five groups, alkanolamines, alkali carbonates, ammonia, amino acid salts, and ionic liquids. The chemistry of the materials is discussed and advantages and drawbacks...

  5. Soybean β-conglycinin induces inflammation and oxidation and causes dysfunction of intestinal digestion and absorption in fish.

    Directory of Open Access Journals (Sweden)

    Jin-Xiu Zhang

    Full Text Available β-Conglycinin has been identified as one of the major feed allergens. However, studies of β-conglycinin on fish are scarce. This study investigated the effects of β-conglycinin on the growth, digestive and absorptive ability, inflammatory response, oxidative status and gene expression of juvenile Jian carp (Cyprinus carpio var. Jian in vivo and their enterocytes in vitro. The results indicated that the specific growth rate (SGR, feed intake, and feed efficiency were reduced by β-conglycinin. In addition, activities of trypsin, chymotrypsin, lipase, creatine kinase, Na(+,K(+-ATPase and alkaline phosphatase in the intestine showed similar tendencies. The protein content of the hepatopancreas and intestines, and the weight and length of the intestines were all reduced by β-conglycinin. β-Conglycinin increased lipid and protein oxidation in the detected tissues and cells. However, β-conglycinin decreased superoxide dismutase (SOD, catalase (CAT, glutathione-S-transferase (GST, glutathione peroxidase (GPx and glutathione reductase (GR activities and glutathione (GSH content in the intestine and enterocytes. Similar antioxidant activity in the hepatopancreas was observed, except for GST. The expression of target of rapamycin (TOR gene was reduced by β-conglycinin. Furthermore, mRNA levels of interleukin-8 (IL-8, tumor necrosis factor-α (TNF-α, and transforming growth factor-β (TGF-β genes were increased by β-conglycinin. However, β-conglycinin increased CuZnSOD, MnSOD, CAT, and GPx1b gene expression. In conclusion, this study indicates that β-conglycinin induces inflammation and oxidation, and causes dysfunction of intestinal digestion and absorption in fish, and finally reduces fish growth. The results of this study provide some information to the mechanism of β-conglycinin-induced negative effects.

  6. Low Buffer Capacity and Alternating Motility along the Human Gastrointestinal Tract: Implications for in Vivo Dissolution and Absorption of Ionizable Drugs.

    Science.gov (United States)

    Hens, Bart; Tsume, Yasuhiro; Bermejo, Marival; Paixao, Paulo; Koenigsknecht, Mark J; Baker, Jason R; Hasler, William L; Lionberger, Robert; Fan, Jianghong; Dickens, Joseph; Shedden, Kerby; Wen, Bo; Wysocki, Jeffrey; Loebenberg, Raimar; Lee, Allen; Frances, Ann; Amidon, Greg; Yu, Alex; Benninghoff, Gail; Salehi, Niloufar; Talattof, Arjang; Sun, Duxin; Amidon, Gordon L

    2017-12-04

    In this study, we determined the pH and buffer capacity of human gastrointestinal (GI) fluids (aspirated from the stomach, duodenum, proximal jejunum, and mid/distal jejunum) as a function of time, from 37 healthy subjects after oral administration of an 800 mg immediate-release tablet of ibuprofen (reference listed drug; RLD) under typical prescribed bioequivalence (BE) study protocol conditions in both fasted and fed states (simulated by ingestion of a liquid meal). Simultaneously, motility was continuously monitored using water-perfused manometry. The time to appearance of phase III contractions (i.e., housekeeper wave) was monitored following administration of the ibuprofen tablet. Our results clearly demonstrated the dynamic change in pH as a function of time and, most significantly, the extremely low buffer capacity along the GI tract. The buffer capacity on average was 2.26 μmol/mL/ΔpH in fasted state (range: 0.26 and 6.32 μmol/mL/ΔpH) and 2.66 μmol/mL/ΔpH in fed state (range: 0.78 and 5.98 μmol/mL/ΔpH) throughout the entire upper GI tract (stomach, duodenum, and proximal and mid/distal jejunum). The implication of this very low buffer capacity of the human GI tract is profound for the oral delivery of both acidic and basic active pharmaceutical ingredients (APIs). An in vivo predictive dissolution method would require not only a bicarbonate buffer but also, more significantly, a low buffer capacity of dissolution media to reflect in vivo dissolution conditions.

  7. Hippo, TGF-β, and Src-MAPK pathways regulate transcription of the upd3 cytokine in Drosophila enterocytes upon bacterial infection.

    Science.gov (United States)

    Houtz, Philip; Bonfini, Alessandro; Liu, Xi; Revah, Jonathan; Guillou, Aurélien; Poidevin, Mickael; Hens, Korneel; Huang, Hsin-Yi; Deplancke, Bart; Tsai, Yu-Chen; Buchon, Nicolas

    2017-11-01

    Cytokine signaling is responsible for coordinating conserved epithelial regeneration and immune responses in the digestive tract. In the Drosophila midgut, Upd3 is a major cytokine, which is induced in enterocytes (EC) and enteroblasts (EB) upon oral infection, and initiates intestinal stem cell (ISC) dependent tissue repair. To date, the genetic network directing upd3 transcription remains largely uncharacterized. Here, we have identified the key infection-responsive enhancers of the upd3 gene and show that distinct enhancers respond to various stresses. Furthermore, through functional genetic screening, bioinformatic analyses and yeast one-hybrid screening, we determined that the transcription factors Scalloped (Sd), Mothers against dpp (Mad), and D-Fos are principal regulators of upd3 expression. Our study demonstrates that upd3 transcription in the gut is regulated by the activation of multiple pathways, including the Hippo, TGF-β/Dpp, and Src, as well as p38-dependent MAPK pathways. Thus, these essential pathways, which are known to control ISC proliferation cell-autonomously, are also activated in ECs to promote tissue turnover the regulation of upd3 transcription.

  8. Styrene maleic acid micelles as a nanocarrier system for oral anticancer drug delivery – dual uptake through enterocytes and M-cells

    Science.gov (United States)

    Parayath, Neha N; Nehoff, Hayley; Müller, Philipp; Taurin, Sebastien; Greish, Khaled

    2015-01-01

    Drug delivery systems could potentially overcome low bioavailability and gastrointestinal toxicity, which are the major challenges for the development of oral anticancer drugs. Herein, we demonstrate the ability of styrene maleic acid (SMA) nanomicelles encapsulating epirubicin to traverse in vitro and ex vivo models of the intestinal epithelium without affecting the tissue integrity. Further, SMA micelles encapsulating a fluorescent dye dioctadecyl-3,3,3′,3′-tetramethylindocarbocyanine perchlorate (DiI) showed twofold higher accumulation in the liver and spleen, 15-fold higher accumulation in the tumor, and sixfold higher accumulation in the lung as compared with the free DiI, following oral administration in a mice xenograft breast cancer model. Additionally, SMA micelles showed colocalization with microfold (M)-cells and accumulation in Peyer’s patches, which together confirms the M-cell mediated uptake and transport of SMA micelles. Our results indicate that SMA micelles, showing dual uptake by enterocytes and M-cells, are a potential tool for safe oral anticancer drug delivery. PMID:26229468

  9. Styrene maleic acid micelles as a nanocarrier system for oral anticancer drug delivery - dual uptake through enterocytes and M-cells.

    Science.gov (United States)

    Parayath, Neha N; Nehoff, Hayley; Müller, Philipp; Taurin, Sebastien; Greish, Khaled

    2015-01-01

    Drug delivery systems could potentially overcome low bioavailability and gastrointestinal toxicity, which are the major challenges for the development of oral anticancer drugs. Herein, we demonstrate the ability of styrene maleic acid (SMA) nanomicelles encapsulating epirubicin to traverse in vitro and ex vivo models of the intestinal epithelium without affecting the tissue integrity. Further, SMA micelles encapsulating a fluorescent dye dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate (DiI) showed twofold higher accumulation in the liver and spleen, 15-fold higher accumulation in the tumor, and sixfold higher accumulation in the lung as compared with the free DiI, following oral administration in a mice xenograft breast cancer model. Additionally, SMA micelles showed colocalization with microfold (M)-cells and accumulation in Peyer's patches, which together confirms the M-cell mediated uptake and transport of SMA micelles. Our results indicate that SMA micelles, showing dual uptake by enterocytes and M-cells, are a potential tool for safe oral anticancer drug delivery.

  10. Protective Effects of Bifidobacterium on Intestinal Barrier Function in LPS-Induced Enterocyte Barrier Injury of Caco-2 Monolayers and in a Rat NEC Model.

    Science.gov (United States)

    Ling, Xiang; Linglong, Peng; Weixia, Du; Hong, Wei

    2016-01-01

    Zonulin protein is a newly discovered modulator which modulates the permeability of the intestinal epithelial barrier by disassembling intercellular tight junctions (TJ). Disruption of TJ is associated with neonatal necrotizing enterocolitis (NEC). It has been shown bifidobacterium could protect the intestinal barrier function and prophylactical administration of bifidobacterium has beneficial effects in NEC patients and animals. However, it is still unknown whether the zonulin is involved in the gut barrier dysfunction of NEC, and the protective mechanisms of bifidobacterium on intestinal barrier function are also not well understood. The present study aims to investigate the effects of bifidobacterium on intestinal barrier function, zonulin regulation, and TJ integrity both in LPS-induced enterocyte barrier injury of Caco-2 monolayers and in a rat NEC model. Our results showed bifidobacterium markedly attenuated the decrease in transepithelial electrical resistance and the increase in paracellular permeability in the Caco-2 monolayers treated with LPS (P bifidobacterium significantly decreased the production of IL-6 and TNF-α (P bifidobacterium pretreatment up-regulated occludin, claudin-3 and ZO-1 expression (P bifidobacterium decreased the incidence of NEC from 88 to 47% (P bifidobacterium treated rats (P bifidobacterium attenuated the increase in intestinal permeability (P bifidobacterium may protect against intestinal barrier dysfunction both in vitro and in NEC. This protective effect is associated with inhibition of proinflammatory cytokine secretion, suppression of zonulin protein release and improvement of intestinal TJ integrity.

  11. Revisiting Absorptive Capacity

    DEFF Research Database (Denmark)

    de Araújo, Ana Luiza Lara; Ulhøi, John Parm; Lettl, Christopher

    Absorptive capacity has mostly been perceived as a 'passive' outcome of R&D investments. Recently, however, a growing interest into its 'proactive' potentials has emerged. This paper taps into this development and proposes a dynamic model for conceptualizing the determinants of the complementary ...... processes, with emphasis on exploitative learning. Before concluding, the paper addresses implications for theory and practice and limitations of this study....

  12. Relic Neutrino Absorption Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Eberle, b

    2004-01-28

    Resonant annihilation of extremely high-energy cosmic neutrinos on big-bang relic anti-neutrinos (and vice versa) into Z-bosons leads to sizable absorption dips in the neutrino flux to be observed at Earth. The high-energy edges of these dips are fixed, via the resonance energies, by the neutrino masses alone. Their depths are determined by the cosmic neutrino background density, by the cosmological parameters determining the expansion rate of the universe, and by the large redshift history of the cosmic neutrino sources. We investigate the possibility of determining the existence of the cosmic neutrino background within the next decade from a measurement of these absorption dips in the neutrino flux. As a by-product, we study the prospects to infer the absolute neutrino mass scale. We find that, with the presently planned neutrino detectors (ANITA, Auger, EUSO, OWL, RICE, and SalSA) operating in the relevant energy regime above 10{sup 21} eV, relic neutrino absorption spectroscopy becomes a realistic possibility. It requires, however, the existence of extremely powerful neutrino sources, which should be opaque to nucleons and high-energy photons to evade present constraints. Furthermore, the neutrino mass spectrum must be quasi-degenerate to optimize the dip, which implies m{sub {nu}} 0.1 eV for the lightest neutrino. With a second generation of neutrino detectors, these demanding requirements can be relaxed considerably.

  13. Involvement of organic anion transporting polypeptide 1a5 (Oatp1a5) in the intestinal absorption of endothelin receptor antagonist in rats

    DEFF Research Database (Denmark)

    Tani, Takeshi; Gram, Luise K; Arakawa, Hiroshi

    2008-01-01

    PURPOSE: To assess the contribution of organic anion transporting polypeptide 1a5 (Oatp1a5/Oatp3) in the intestinal absorption of an orally active endothelin receptor antagonist, (+)-(5S,6R,7R)-2-butyl-7-[2-((2S)-2-carboxypropyl)-4-methoxyphenyl]-5-(3,4-methylene-dioxyphenyl)cyclopenteno[1,2-b......]pyridine-6-carboxylic acid (compound-A) in rats. METHODS: Uptakes of [(14)C]compound-A by Oatp1a5-expressing Xenopus laevis oocytes and isolated rat enterocytes were evaluated. RESULTS: The uptake of compound-A by Oatp1a5-expressing oocytes was significantly higher than that by water-injected oocytes...... and Oatp1a5-mediated uptake was saturable with K(m) value of 116 microM. Compound-A was taken up into isolated enterocytes in time- and concentration-dependent manners and the estimated K(m) value was 83 microM, which was close to that for the Oatpt1a5-mediated uptake in oocytes. Both uptakes of compound...

  14. Zinc absorption from milk is affected by dilution but not by thermal processing, and milk enhances absorption of Zinc from high-phytate rice in young dutch women

    NARCIS (Netherlands)

    Talsma, Elise F.; Moretti, Diego; Ly, Sou Chheng; Dekkers, Renske; Heuvel, van den Ellen G.H.M.; Fitri, Aditia; Boelsma, Esther; Stomph, Tjeerd Jan; Zeder, Christophe; Melse-Boonstra, Alida

    2017-01-01

    Background: Milk has been suggested to increase zinc absorption. The effect of processing and the ability of milk to enhance zinc absorption from other foods has not been measured directly in humans. Objective: We aimed to assess zinc absorption from 1) milk undergoing various processing and

  15. Absorption in periodic layered structures

    OpenAIRE

    Moroz, Alexander; Tip, Adriaan; Combes, Jean-Michel

    2000-01-01

    Photonic band structure of metal-dielectric and semiconductor-dielectric layered structures are studied in the presence of a strong absorption. It is shown that absorption can enlarge some gaps by as much as 50%.

  16. Absorption of americium compounds in the respiratory tract.

    Science.gov (United States)

    Blanchardon, Eric; Davesne, Estelle; Paquet, François; Bailey, Michael

    2014-11-01

    To improve the dosimetry of incorporated americium (Am) and to contribute to radiation protection by characterizing the absorption kinetics of inhaled Am compounds. In vitro dissolution tests, animal experiments and human contamination cases published in the literature were reviewed. The data were analyzed with biokinetic models consistent with the current publications of the International Commission on Radiological Protection. Material-specific dissolution parameter values with consequent assignment to absorption Types are proposed as well as representative central values for the different chemical forms of Am. The absorption of Am oxide is consistent with the moderate absorption Type M while Am nitrate appears more soluble. Am associated with plutonium oxide usually follows its slow absorption Type S. However, the large variability observed stresses the value of investigating the specific absorption kinetics for Am compounds which represent a significant risk of internal exposure.

  17. Subgap Absorption in Conjugated Polymers

    Science.gov (United States)

    Sinclair, M.; Seager, C. H.; McBranch, D.; Heeger, A. J; Baker, G. L.

    1991-01-01

    Along with X{sup (3)}, the magnitude of the optical absorption in the transparent window below the principal absorption edge is an important parameter which will ultimately determine the utility of conjugated polymers in active integrated optical devices. With an absorptance sensitivity of fluorination.

  18. Absorption characteristics of bacteriorhodopsin molecules

    Indian Academy of Sciences (India)

    The analytical expression for the absorption coefficient of BR film is applied to study the absorption characteristics of BR molecules in a typical laser system operating at funda- mental wavelength 514 nm. The experimental data available for the absorption coefficients of the levels B and M corresponding to the wavelength ...

  19. Rapidly variable relatvistic absorption

    Science.gov (United States)

    Parker, M.; Pinto, C.; Fabian, A.; Lohfink, A.; Buisson, D.; Alston, W.; Jiang, J.

    2017-10-01

    I will present results from the 1.5Ms XMM-Newton observing campaign on the most X-ray variable AGN, IRAS 13224-3809. We find a series of nine absorption lines with a velocity of 0.24c from an ultra-fast outflow. For the first time, we are able to see extremely rapid variability of the UFO features, and can link this to the X-ray variability from the inner accretion disk. We find a clear flux dependence of the outflow features, suggesting that the wind is ionized by increasing X-ray emission.

  20. Absorption in dielectric models

    CERN Document Server

    Churchill, R J

    2015-01-01

    We develop a classical microscopic model of a dielectric. The model features nonlinear interaction terms between polarizable dipoles and lattice vibrations. The lattice vibrations are found to act as a pseudo-reservoir, giving broadband absorption of electromagnetic radiation without the addition of damping terms in the dynamics. The effective permittivity is calculated using a perturbative iteration method and is found to have the form associated with real dielectrics. Spatial dispersion is naturally included in the model and we also calculate the wavevector dependence of the permittivity.

  1. Geospatial Absorption and Regional Effects

    Directory of Open Access Journals (Sweden)

    IOAN MAC

    2009-01-01

    Full Text Available The geospatial absorptions are characterized by a specific complexity both in content and in their phenomenological and spatial manifestation fields. Such processes are differentiated according to their specificity to pre-absorption, absorption or post-absorption. The mechanisms that contribute to absorption are extremely numerous: aggregation, extension, diffusion, substitution, resistivity (resilience, stratification, borrowings, etc. Between these mechanisms frequent relations are established determining an amplification of the process and of its regional effects. The installation of the geographic osmosis phenomenon in a given territory (a place for example leads to a homogenization of the geospatial state and to the installation of the regional homogeneity.

  2. Suppression subtractive hybridization identifies bacterial genomic regions that are possibly involved in hBD-2 regulation by enterocytes.

    Science.gov (United States)

    Ghadimi, Darab; Hassan, Mohamed; Njeru, Patrisio Njiru; de Vrese, Michael; Geis, Arnold; Shalabi, Samweul I; Abdel-Razek, Sabah T; Abdel-Khair, Abd El-Al A; Heller, Knut J; Schrezenmeir, Jürgen

    2011-10-01

    Human β-defensin 2 (hBD-2) is an inducible antimicrobial peptide synthesized by the epithelium to counteract bacterial adherence and invasion. It has been suggested that probiotic bacteria sustain gut barrier function via induction of defensins. The goals of this study were (i) to evaluate the potential immunomodulatory effects of 11 different Lactobacillus fermentum strains isolated from Kimere, an African fermented pearl millet (Pennisetum glaucum) dough, on the hBD-2 secretion by human intestinal CaCo-2 cell line and (ii) to examine genetic differences between two strains of L. fermentum (K2-Lb4 and K11-Lb3) which differed in their effect on the production of hBD-2 in this study. Totally, 46 strains of L. fermentum from Kimere were isolated and characterized using molecular biology methods including pulsed-field gel electrophoresis patterns. After performing time- and dose-experiments, CaCo-2 cells were incubated with or without bacteria for 12 h. L. fermentum PZ1162 was included as the positive control. Cell-free supernatants were analyzed for hBD-2 protein by enzyme-linked immunosorbent assay (ELISA). To identify potential bacterial genes associated with hBD-2 regulation, suppression subtractive hybridization (SSH) was used. Among the 11 strains tested, only two strains of bacteria, K11-Lb3 and K2-Lb6, significantly induced the production of hBD-2 by CaCo-2 cells. This effect was strain-specific, dose-dependent and particularly seems to be bacterial genomic-dependent as manifested by SSH. L. fermentum strains with and without hBD-2 inducing effect differed in genes encoding proteins involved in glycosylation of cell-wall proteins e.g. glycosyltransferase, UDP-N-acetylglucosamine 2-epimerase, rod shape-determining protein MreC, lipoprotein precursors, sugar ABC transporters, and glutamine ABC transporter ATP-binding protein. This study implies that certain strains of L. fermentum isolated from Kimere may stimulate the intestinal innate defense through the

  3. Skin absorption through atopic dermatitis skin

    DEFF Research Database (Denmark)

    Halling-Overgaard, A-S; Kezic, S; Jakasa, I

    2017-01-01

    Patients with atopic dermatitis have skin barrier impairment in both lesional and non-lesional skin. They are typically exposed to emollients daily and topical anti-inflammatory medicaments intermittently, hereby increasing the risk of developing contact allergy and systemic exposed to chemicals...... ingredients found in these topical preparations. We systematically searched for studies that investigated skin absorption of various penetrants, including medicaments, in atopic dermatitis patients, but also animals with experimentally induced dermatitis. We identified 40 articles, i.e. 11 human studies...... examining model penetrants, 26 human studies examining atopic dermatitis drugs and 3 animal studies. We conclude that atopic dermatitis patients have nearly two-fold increased skin absorption when compared to healthy controls. There is a need for well-designed epidemiological and dermato...

  4. Training and business performance: the mediating role of absorptive capacities.

    Science.gov (United States)

    Hernández-Perlines, Felipe; Moreno-García, Juan; Yáñez-Araque, Benito

    2016-01-01

    Training has been the focus of considerable conceptual and empirical attention but is considered a relevant factor for competitive edge in companies because it has a positive impact on business performance. This study is justified by the need for deeper analysis of the process involving the transfer of training into performance. This paper's originality lies in the implementation of the absorptive capacities approach as an appropriate conceptual framework for designing a model that reflects the connection between training and business performance through absorptive capacities. Based on the above conceptual framework and using the dual methodological implementation, a new method of analyzing the relationship between training and performance was obtained: efforts in training will not lead to performance without the mediation of absorptive. Training turns into performance if absorptive capacities are involved in this process. The suggested model becomes an appropriate framework for explaining the process of transformation of training into organizational performance, in which absorptive capacities play a key role. The findings obtained can go further owing to fs/QCA: of the different absorptive capacities, that of exploitation is a necessary condition to achieve better organizational performance. Therefore, training based on absorptive capacity will guide and facilitate the design of appropriate human resource strategies so that training results in improved performance. This conclusion is relevant for the development of a new facet of absorptive capacities by relating it to training and resulting in first-level implications for human resource management.

  5. Sabine absorption coefficients to random incidence absorption coefficients

    DEFF Research Database (Denmark)

    Jeong, Cheol-Ho

    2014-01-01

    into random incidence absorption coefficients for porous absorbers are investigated. Two optimization-based conversion methods are suggested: the surface impedance estimation for locally reacting absorbers and the flow resistivity estimation for extendedly reacting absorbers. The suggested conversion methods......Absorption coefficients measured by the chamber method are referred to as Sabine absorption coefficients, which sometimes exceed unity due to the finite size of a specimen and non-uniform intensity in the test chamber. In this study, several methods that convert Sabine absorption coefficients...

  6. Persistent sample circulation microextraction combined with graphite furnace atomic absorption spectroscopy for trace determination of heavy metals in fish species marketed in Kermanshah, Iran and human health risk assessment.

    Science.gov (United States)

    Safari, Yahya; Karimaei, Mostafa; Sharafi, Kiomars; Arfaeinia, Hossein; Moradi, Masoud; Fattahi, Nazir

    2017-11-21

    The persistent sample circulation microextraction (PSCME) joined with the graphite furnace atomic absorption spectrometry (GFAAS) was developed as a high preconcentration technique for the determination of heavy metals in fish species. In this method, a few microliter of organic solvent (40.0 µl carbon tetrachloride) was transferred to the bottom of a conical sample cup. Then a 10.0 ml of aqueous solution transformed to fine droplets while passing through an organic solvent. At this stage, metal-ligand hydrophobic complex was extracted into the organic solvent. After extraction, 20 µl of extraction solvent was injected into the graphite tube using an auto-sampler. Under the optimum conditions, enrichment factors and enhancement factor were in the range of 180-240 and 155-214, respectively. The calibration curves were linear in the range of 0.03-200 µg kg-1 and the limits of detections (LODs) were in the range of 0.01-0.05 µg kg-1 . The Repeatability (intra-day) and reproducibility (inter-day) for 0.50 µg l-1 of Hg and 0.10 µg l-1 of Cd and Pb were in the range of 3.1-4.2% (n = 7) and 4.3-6.1% (n = 7), respectively. A potential human health risk assessment was conducted by calculating estimated weekly intake (EWI) of the metals from eating fish and comparison of these values with provisional tolerable weekly intake (PTWI) values. EWI data for the studied metals through fish consumption were lower than the PTWI values. This article is protected by copyright. All rights reserved.

  7. Sweet taste receptors in rat small intestine stimulate glucose absorption through apical GLUT2

    Science.gov (United States)

    Mace, Oliver J; Affleck, Julie; Patel, Nick; Kellett, George L

    2007-01-01

    Natural sugars and artificial sweeteners are sensed by receptors in taste buds. T2R bitter and T1R sweet taste receptors are coupled through G-proteins, α-gustducin and transducin, to activate phospholipase C β2 and increase intracellular calcium concentration. Intestinal brush cells or solitary chemosensory cells (SCCs) have a structure similar to lingual taste cells and strongly express α-gustducin. It has therefore been suggested over the last decade that brush cells may participate in sugar sensing by a mechanism analogous to that in taste buds. We provide here functional evidence for an intestinal sensing system based on lingual taste receptors. Western blotting and immunocytochemistry revealed that all T1R members are expressed in rat jejunum at strategic locations including Paneth cells, SCCs or the apical membrane of enterocytes; T1Rs are colocalized with each other and with α-gustducin, transducin or phospholipase C β2 to different extents. Intestinal glucose absorption consists of two components: one is classical active Na+–glucose cotransport, the other is the diffusive apical GLUT2 pathway. Artificial sweeteners increase glucose absorption in the order acesulfame potassium ∼ sucralose > saccharin, in parallel with their ability to increase intracellular calcium concentration. Stimulation occurs within minutes by an increase in apical GLUT2, which correlates with reciprocal regulation of T1R2, T1R3 and α-gustducin versus T1R1, transducin and phospholipase C β2. Our observation that artificial sweeteners are nutritionally active, because they can signal to a functional taste reception system to increase sugar absorption during a meal, has wide implications for nutrient sensing and nutrition in the treatment of obesity and diabetes. PMID:17495045

  8. X-ray Absorption Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Yano, Junko; Yachandra, Vittal K.

    2009-07-09

    This review gives a brief description of the theory and application of X-ray absorption spectroscopy, both X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS), especially, pertaining to photosynthesis. The advantages and limitations of the methods are discussed. Recent advances in extended EXAFS and polarized EXAFS using oriented membranes and single crystals are explained. Developments in theory in understanding the XANES spectra are described. The application of X-ray absorption spectroscopy to the study of the Mn4Ca cluster in Photosystem II is presented.

  9. Protein Hydrolysates as Promoters of Non-Haem Iron Absorption

    Directory of Open Access Journals (Sweden)

    Yanan Li

    2017-06-01

    Full Text Available Iron (Fe is an essential micronutrient for human growth and health. Organic iron is an excellent iron supplement due to its bioavailability. Both amino acids and peptides improve iron bioavailability and absorption and are therefore valuable components of iron supplements. This review focuses on protein hydrolysates as potential promoters of iron absorption. The ability of protein hydrolysates to chelate iron is thought to be a key attribute for the promotion of iron absorption. Iron-chelatable protein hydrolysates are categorized by their absorption forms: amino acids, di- and tri-peptides and polypeptides. Their structural characteristics, including their size and amino acid sequence, as well as the presence of special amino acids, influence their iron chelation abilities and bioavailabilities. Protein hydrolysates promote iron absorption by keeping iron soluble, reducing ferric iron to ferrous iron, and promoting transport across cell membranes into the gut. We also discuss the use and relative merits of protein hydrolysates as iron supplements.

  10. Phytases for improved iron absorption

    DEFF Research Database (Denmark)

    Nielsen, Anne Veller Friis; Meyer, Anne S.

    2016-01-01

    Phytase enzymes present an alternative to iron supplements, because they have been shown to improve iron absorption by means of catalysing the degradation of a potent iron absorption inhibitor: phytic acid. Phytic acid is a hexaphosphate of inositol and is particularly prevalent in cereal grains...

  11. Wave energy absorption by ducks

    DEFF Research Database (Denmark)

    Kurniawan, Adi

    2017-01-01

    We study the absorption of wave energy by a single and multiple cam-shaped bodies referred to as ducks. Numerical models are developed under the assumptions of linear theory. We consider wave absorption by a single duck as well as by two lines of ducks meeting at an angle....

  12. Water absorption in brick masonry

    NARCIS (Netherlands)

    Brocken, H.J.P.; Smolders, H.R.

    1996-01-01

    The water absorption in brick, mortar that was cured separately, and masonry samples was studied using NMR. Models of the moisture transport are usually formulated on the basis of a diffusion equation. In the case of water absorption in separate brick and mortar samples, the moisture diffusivity in

  13. The unresolved role of dietary fibers on mineral absorption

    OpenAIRE

    Baye, K.; Guyot, Jean-Pierre; Mouquet Rivier, Claire

    2017-01-01

    Dietary fiber is a complex nutritional concept whose definition and method of analysis has evolved over time. However, literature on the role of dietary fiber on mineral bioavailability has not followed pace. Although in vitro studies revealed mineral binding properties, both animal and human studies failed to show negative effects on mineral absorption, and even in some cases reported absorption enhancing properties. The existing literature suggests that dietary fibers have negative effects ...

  14. Antibiotics Suppress Activation of Intestinal Mucosal Mast Cells and Reduce Dietary Lipid Absorption in Sprague-Dawley Rats.

    Science.gov (United States)

    Sato, Hirokazu; Zhang, Linda S; Martinez, Kristina; Chang, Eugene B; Yang, Qing; Wang, Fei; Howles, Philip N; Hokari, Ryota; Miura, Soichiro; Tso, Patrick

    2016-11-01

    The gut microbiota affects intestinal permeability and mucosal mast cells (MMCs) responses. Activation of MMCs has been associated with absorption of dietary fat. We investigated whether the gut microbiota contributes to the fat-induced activation of MMCs in rats, and how antibiotics might affect this process. Adult male Sprague-Dawley rats were given streptomycin and penicillin for 4 days (n = 6-8) to reduce the abundance of their gut flora, or normal drinking water (controls, n = 6-8). They underwent lymph fistula surgery and after an overnight recovery were given an intraduodenal bolus of intralipid. We collected intestinal tissues and lymph fluid and assessed activation of MMCs, intestinal permeability, and fat transport parameters. Compared with controls, intestinal lymph from rats given antibiotics had reduced levels of mucosal mast cell protease II (produced by MMCs) and decreased activity of diamine oxidase (produced by enterocytes) (P antibiotics had reduced intestinal permeability in response to dietary lipid compared with controls (P antibiotics also reduced lymphatic transport of triacylglycerol and phospholipid (P antibiotics and controls. These effects were not seen with an acute dose of antibiotics or 4 weeks after the antibiotic regimen ended. The intestinal microbiota appears to activate MMCs after the ingestion of fat in rats; this contributes to fat-induced intestinal permeability. We found that the gut microbiome promotes absorption of lipid, probably by intestinal production of apolipoproteins and secretion of chylomicrons. Copyright © 2016 AGA Institute. Published by Elsevier Inc. All rights reserved.

  15. EM absorption reduction in wireless mobile antenna using printed paper-based metamaterial

    Science.gov (United States)

    Alam, Touhidul; Islam, Mohammad Tariqul; Kibria, Salehin; Cho, Mengu; Faruque, Mohammad Rashed Iqbal

    2017-01-01

    This paper presents a printed negative index metamaterial for electromagnetic (EM) absorption reduction in portable wireless antenna. The perceptible novelty exhibited in this paper is that EM absorption reduction toward the human head with paper-based metamaterial attachment. This research has been performed using human head phantom integrated in the commercially available CST Microwave Studio software package. The EM absorption has been reduced by 13.2 and 6% at 900 and 1800 MHz, respectively.

  16. Modelos in vitro para determinação da absorção de fármacos e previsão da relação dissolução/absorção In vitro models for the determination of drug absorption and a prediction of dissolution/absorption relationships

    Directory of Open Access Journals (Sweden)

    Jacqueline de Souza

    2007-12-01

    and absorption of drugs using in vitro models. There are several methods for determining in vitro intestinal permeability. These include diffusion studies with intestinal segments from various species or with cultured cell monolayer. Some of the most commonly used cell models are Caco-2, TC-7, 2/4/A1 and MDCK. Caco-2 cells have been the most extensively characterized and useful cell models. The Caco-2 cell, a human colon adenocarcinoma, undergoes spontaneous enterocytic differentiation in culture. A dissolution Caco-2 system has been developed to predict dissolution/absorption relationships of oral solid dosage forms of drugs prior to human studies. The in vitro permeability models represent an important tool for drug discovery within the pharmaceutical industry. However, similar models are likely to generate false negative results with actively transported drugs, and the use of a sophisticated mathematical model could be required.

  17. The expected time until absorption when absorption is not certain

    OpenAIRE

    Walker, D. M.

    1998-01-01

    This paper considers continuous-time Markov chains whose state space consists of an irreducible class, , and an absorbing state which is accessible from . The purpose is to provide a way to determine the expected time to absorption conditional on such time being finite, in the case where absorption occurs with probability less than 1. The results are illustrated by applications to the general birth and death process and the linear birth, death and catastrophe process.

  18. Dietary inulin affects the expression of intestinal enterocyte iron transporters, receptors and storage protein and alters the microbiota in the pig intestine

    Science.gov (United States)

    Inulin, a linear beta fructan, is present in a variety of plants including chicory root and wheat. It exhibits prebiotic properties and was shown to enhance mineral absorption and increase beneficial bacteria in the colon. The aim of this study was to assess the effect of dietary inulin on selected...

  19. The effect of Pro NanoLipospheres (PNL) formulation containing natural absorption enhancers on the oral bioavailability of delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD) in a rat model.

    Science.gov (United States)

    Cherniakov, Irina; Izgelov, Dvora; Domb, Abraham J; Hoffman, Amnon

    2017-11-15

    The lipophilic phytocannabinoids cannabidiol (CBD) and Δ9-tetrahydrocannabinol (THC) show therapeutic efficacy in various medical conditions. Both molecules are poorly water soluble and subjected to extensive first pass metabolism in the gastrointestinal tract, leading to a limited oral bioavailability of approximately 9%. We have developed an advanced lipid based Self-Emulsifying Drug Delivery System termed Advanced Pro-NanoLiposphere (PNL) pre-concentrate. The PNL is composed of lipid and emulsifying excipients of GRAS status and are known to increase solubility and reduce Phase I metabolism of lipophilic active compounds. Advanced PNLs are PNLs with an incorporated natural absorption enhancers. These molecules are natural alkaloids and phenolic compounds which were reported to inhibit certain phase I and phase II metabolism processes. Here we use piperine, curcumin and resveratrol to formulate the Advanced-PNL formulations. Consequently, we have explored the utility of these Advanced-PNLs on CBD and THC oral bioavailability. Oral administration of CBD-piperine-PNL resulted in 6-fold increase in AUC compared to CBD solution, proving to be the most effective of the screened formulations. The same trend was found in pharmacokinetic experiments of THC-piperine-PNL which resulted in a 9.3-fold increase in AUC as compared to THC solution. Our Piperine-PNL can be used as a platform for synchronized delivery of piperine and CBD or THC to the enterocyte site. This co-localization provides an increase in CBD and THC bioavailability by its effect at the pre-enterocyte and the enterocyte levels of the absorption process. The extra augmentation in the absorption of CBD and THC by incorporating piperine into PNL is attributed to the inhibition of Phase I and phase II metabolism by piperine in addition to the Phase I metabolism and P-gp inhibition by PNL. These novel results pave the way to utilize piperine-PNL delivery system for other poorly soluble, highly metabolized

  20. Reproducibility of The Random Incidence Absorption Coefficient Converted From the Sabine Absorption Coefficient

    DEFF Research Database (Denmark)

    Jeong, Cheol-Ho; Chang, Ji-ho

    2015-01-01

    Absorption coefficients measured in reverberation chambers, Sabine absorption coefficients, suffer from two major problems. Firstly, they sometimes exceed unity. Secondly, the reproducibility of the Sabine absorption coefficients is quite poor, meaning that the Sabine absorption coefficients vary...

  1. Time dependent effects of two absorption enhancers on the nasal absorption of growth hormone in rabbits

    DEFF Research Database (Denmark)

    Vermehren, C.; Hansen, Harald S.; Thomsen, M.K.

    1996-01-01

    Enhancer-based drug preparations allow absorption of peptide drugs. We investigated the reversibility with time of nasal absorption of human growth hormone (hGH) induced by the absorption enhancers didecanoylphosphatidylcholine (DDPC) and a-cyclodextrin (a-CD). Rabbits were dosed intranasally...... with enhancer in the absence of hGH at time -3, -1, -0.5 and 0 h. At time zero the same groups of rabbits were dosed with a hGH powder devoid of the enhancers. Values for plasma hGH AUC and C(max) were estimated in order to measure the degree of absorption, and rabbits receiving hGH together with enhancers were...... the tissue. Similar findings were obtained with a-CD alone, whereas a preparation containing only DDPC showed no recovery of leakiness. The effect of a-CD was also investigated in vitro in rabbit nasal mucosa mounted in Ussing chambers. Incubation for 15 min with 1, 3 and 8% a-CD induced a concentration...

  2. Time dependent effects of two absorption enhancers on the nasal absorption of growth hormone in rabbits

    DEFF Research Database (Denmark)

    Vermehren, Charlotte; Hansen, H.S.; Thomsen, M.K.

    1996-01-01

    Enhancer-based drug preparations allow absorption of peptid drugs. We investigated the reversibility with time of nasal absorption of human growth hormone (hGH) induced by the absorption enhancers didecanoylhposphatidylcholine (DDPC) and Ó-cyclodextrin (Ó-CD). Rabbits were dosed intranasally...... with enhancer in the absence of hGH at time -3, -1, -0.5 and 0 h. At time zero the same groups of rabbits were dosed with a hGH powder devoid of the enhancers. Values for plasma hGH AUC and Cmax were estimated in order to measure the degree of absorption, and rabbits receiving hGH together with enhancers were...... the tissue. Similar findings were obtained with Ó-CD alone, whereas a preparation containing only DDPC showed no recovery of leakiness. The effect of Ó-CD was also investigated in vitro in rabbit nasal mucosa mounted in Ussing chambers. Incubation ofr 15 min with 1, 3 and 8% Ó-CD induced a concentration...

  3. Sound absorption of textile material using a microfibres resistive layer

    Science.gov (United States)

    Segura Alcaraz, M. P.; Bonet-Aracil, M.; Segura Alcaraz, J. G.; Montava Seguí, I.

    2017-10-01

    Acoustic comfort is a basic human need. One of the adverse effects of noise is its interference with speech discrimination. Textile materials are suitable to be used as sound absorptive materials and thus help to improve acoustic comfort in rooms. Micro-fibre fabrics can be considered as better sound absorbers than regular fibre fabrics mainly due to the higher surface of its fibres and bigger contact area with the air thus, allowing greater dissipation of sound energy. In this work, the use of a microfibre woven fabric as an upstream layer is analysed considering acoustic issues. Authors demonstrate it improves the sound absorption of a polyester nonwoven, resulting in a material suitable for absorption at the sound frequencies of the human voice.

  4. Enhanced absorption cycle computer model

    Science.gov (United States)

    Grossman, G.; Wilk, M.

    1993-09-01

    Absorption heat pumps have received renewed and increasing attention in the past two decades. The rising cost of electricity has made the particular features of this heat-powered cycle attractive for both residential and industrial applications. Solar-powered absorption chillers, gas-fired domestic heat pumps, and waste-heat-powered industrial temperature boosters are a few of the applications recently subjected to intensive research and development. The absorption heat pump research community has begun to search for both advanced cycles in various multistage configurations and new working fluid combinations with potential for enhanced performance and reliability. The development of working absorption systems has created a need for reliable and effective system simulations. A computer code has been developed for simulation of absorption systems at steady state in a flexible and modular form, making it possible to investigate various cycle configurations with different working fluids. The code is based on unit subroutines containing the governing equations for the system's components and property subroutines containing thermodynamic properties of the working fluids. The user conveys to the computer an image of his cycle by specifying the different subunits and their interconnections. Based on this information, the program calculates the temperature, flow rate, concentration, pressure, and vapor fraction at each state point in the system, and the heat duty at each unit, from which the coefficient of performance (COP) may be determined. This report describes the code and its operation, including improvements introduced into the present version. Simulation results are described for LiBr-H2O triple-effect cycles, LiCl-H2O solar-powered open absorption cycles, and NH3-H2O single-effect and generator-absorber heat exchange cycles. An appendix contains the user's manual.

  5. Absorption Efficiency of Receiving Antennas

    DEFF Research Database (Denmark)

    Andersen, Jørgen Bach; Frandsen, Aksel

    2005-01-01

    A receiving antenna with a matched load will always scatter some power. This paper sets an upper and a lower bound on the absorption efficiency (absorbed power over sum of absorbed and scattered powers), which lies between 0 and 100% depending on the directivities of the antenna and scatter...... patterns. It can approach 100% as closely as desired, although in practice this may not be an attractive solution. An example with a small endfire array of dipoles shows an efficiency of 93%. Several examples of small conical horn antennas are also given, and they all have absorption efficiencies less than...

  6. Nonlinear absorption in discrete systems

    Energy Technology Data Exchange (ETDEWEB)

    Spire, A; Leon, J [Physique Mathematique et Theorique, CNRS-UMR5825, Universite Montpellier 2, 34095 Montpellier (France)

    2004-10-01

    In the context of nonlinear scattering, a continuous wave incident onto a nonlinear discrete molecular chain of coupled oscillators can be partially absorbed as a result of a three-wave resonant interaction that couples two HF-waves of frequencies close to the edge of the Brillouin zone. Hence both nonlinearity and discreteness are necessary for generating this new absorption process which manifests itself by soliton generation in the medium. As a paradigm of this nonlinear absorption we consider here the Davydov model that describes exciton-phonon coupling in hydrogen-bonded molecular chains.

  7. Absorption-heat-pump system

    Science.gov (United States)

    Grossman, G.; Perez-Blanco, H.

    1983-06-16

    An improvement in an absorption heat pump cycle is obtained by adding adiabatic absorption and desorption steps to the absorber and desorber of the system. The adiabatic processes make it possible to obtain the highest temperature in the absorber before any heat is removed from it and the lowest temperature in the desorber before heat is added to it, allowing for efficient utilization of the thermodynamic availability of the heat supply stream. The improved system can operate with a larger difference between high and low working fluid concentrations, less circulation losses, and more efficient heat exchange than a conventional system.

  8. THE ABSORPTION OF ADRENALIN AFTER INTRATRACHEAL INJECTION.

    Science.gov (United States)

    Auer, J; Gates, F L

    1916-06-01

    In the preceding pages we have submitted evidence which shows that a simple intratracheal injection of a solution in a normally breathing rabbit penetrates within a few seconds to the alveoli, chiefly those of the left lower lobe; that absorption is rapid and well maintained; and that the procedure may be repeated effectively a number of times even with a substance like adrenalin which decreases absorption. It was also shown that absorption of adrenalin from the lung could be obtained at a time when double the dose given intramuscularly exerted no blood pressure effect whatever, and that absorption could still take place after the development of pulmonary edema, when there was an undoubted dilution of the injected solution with a serum-containing liquid and when a diminution of the absorptive field had occurred. The solution injected, after reaching the alveoli, is probably largely taken up by the capillaries of the pulmonary veins. This is indicated by the great rapidity with which an intratracheal injection of adrenalin may cause a rise of blood pressure. In numerous instances, for example, the pressure began to rise less than 5 seconds after the completion of an injection, equaling and even surpassing in rapidity of effect an intramuscular injection. Absorption by the lymphatics probably plays a secondary part, an assumption rendered all themore likely if we consider that lymph nodes are interpolated in the lymphatic pulmonary path, where the bed of the lymph stream becomes greatly widened and the current slowed. Injection into the lungs, however, offers another advantage due to the vascular arrangement of the absorbing field which could be of value therapeutically. Absorption of liquids injected into the lung probably takes place largely through the capillaries of the pulmonary veins; to a slight extent possibly through the capillaries of the bronchial veins which empty partly into the pulmonary veins, partly into the azygos veins; and probably some absorption

  9. Aerosol Absorption Measurements in MILAGRO.

    Science.gov (United States)

    Gaffney, J. S.; Marley, N. A.; Arnott, W. P.; Paredes-Miranda, L.; Barnard, J. C.

    2007-12-01

    During the month of March 2006, a number of instruments were used to determine the absorption characteristics of aerosols found in the Mexico City Megacity and nearby Valley of Mexico. These measurements were taken as part of the Department of Energy's Megacity Aerosol Experiment - Mexico City (MAX-Mex) that was carried out in collaboration with the Megacity Interactions: Local and Global Research Observations (MILAGRO) campaign. MILAGRO was a joint effort between the DOE, NSF, NASA, and Mexican agencies aimed at understanding the impacts of a megacity on the urban and regional scale. A super-site was operated at the Instituto Mexicano de Petroleo in Mexico City (designated T-0) and at the Universidad Technologica de Tecamac (designated T-1) that was located about 35 km to the north east of the T-0 site in the State of Mexico. A third site was located at a private rancho in the State of Hidalgo approximately another 35 km to the northeast (designated T-2). Aerosol absorption measurements were taken in real time using a number of instruments at the T-0 and T-1 sites. These included a seven wavelength aethalometer, a multi-angle absorption photometer (MAAP), and a photo-acoustic spectrometer. Aerosol absorption was also derived from spectral radiometers including a multi-filter rotating band spectral radiometer (MFRSR). The results clearly indicate that there is significant aerosol absorption by the aerosols in the Mexico City megacity region. The absorption can lead to single scattering albedo reduction leading to values below 0.5 under some circumstances. The absorption is also found to deviate from that expected for a "well-behaved" soot anticipated from diesel engine emissions, i.e. from a simple 1/lambda wavelength dependence for absorption. Indeed, enhanced absorption is seen in the region of 300-450 nm in many cases, particularly in the afternoon periods indicating that secondary organic aerosols are contributing to the aerosol absorption. This is likely due

  10. Effect of lutein on beta-carotene absorption and cleavage

    NARCIS (Netherlands)

    Berg, H. van den

    1998-01-01

    Carotenoid interactions during absorption anti in postabsorptive metabolism have been observed in both human and animal studies. We reviewed the mutual interactions reported between lutein and β-carotene and report new data on the postprandial β-carotene and retinyl ester response in the

  11. Rectal absorption of morphine from controlled release suppositories

    NARCIS (Netherlands)

    Moolenaar, Frits; Meyler, Pim; Frijlink, Erik; Jauw, Tjoe Hang; Visser, Jan; Proost, Johannes

    1995-01-01

    The absorption profiles and bioavailability of morphine in human volunteers (n = 13) were described after oral administration of MS Contin tablets and rectal administration of a newly developed controlled release suppository. By manipulating the viscosity of fatty suppository base an entirely

  12. Low-Absorption Laser Windows

    Science.gov (United States)

    1976-04-01

    ABSORPTION MEASUREMENTS AT 1.06 Urn James W. Davisson U.S. Naval Research Laboratory Washington, D.C. 20375 ABSTRACT A procedure for the chemical poli...W. Davisson , Fourth Laser Window Materials Conf. p. 466). The alkaline earth fluorides and LiF were mechanically polished by rubbing: till dry

  13. Theory of graphene saturable absorption

    Science.gov (United States)

    Marini, A.; Cox, J. D.; García de Abajo, F. J.

    2017-03-01

    Saturable absorption is a nonperturbative nonlinear optical phenomenon that plays a pivotal role in the generation of ultrafast light pulses. Here we show that this effect emerges in graphene at unprecedentedly low light intensities, thus opening avenues to new nonlinear physics and applications in optical technology. Specifically, we theoretically investigate saturable absorption in extended graphene by developing a semianalytical nonperturbative single-particle approach, describing electron dynamics in the atomically-thin material using the two-dimensional Dirac equation for massless Dirac fermions, which is recast in the form of generalized Bloch equations. By solving the electron dynamics nonperturbatively, we account for both interband and intraband contributions to the intensity-dependent saturated conductivity and conclude that the former dominates regardless of the intrinsic doping state of the material. We obtain results in qualitative agreement with atomistic quantum-mechanical simulations of graphene nanoribbons including electron-electron interactions, finite-size, and higher-band effects. Remarkably, such effects are found to affect mainly the linear absorption, while the predicted saturation intensities are in good quantitative agreement in the limit of extended graphene. Additionally, we find that the modulation depth of saturable absorption in graphene can be electrically manipulated through an externally applied gate voltage. Our results are relevant for the development of graphene-based optoelectronic devices, as well as for applications in mode-locking and random lasers.

  14. Aerosol absorption and radiative forcing

    Directory of Open Access Journals (Sweden)

    P. Stier

    2007-10-01

    Full Text Available We present a comprehensive examination of aerosol absorption with a focus on evaluating the sensitivity of the global distribution of aerosol absorption to key uncertainties in the process representation. For this purpose we extended the comprehensive aerosol-climate model ECHAM5-HAM by effective medium approximations for the calculation of aerosol effective refractive indices, updated black carbon refractive indices, new cloud radiative properties considering the effect of aerosol inclusions, as well as by modules for the calculation of long-wave aerosol radiative properties and instantaneous aerosol forcing. The evaluation of the simulated aerosol absorption optical depth with the AERONET sun-photometer network shows a good agreement in the large scale global patterns. On a regional basis it becomes evident that the update of the BC refractive indices to Bond and Bergstrom (2006 significantly improves the previous underestimation of the aerosol absorption optical depth. In the global annual-mean, absorption acts to reduce the short-wave anthropogenic aerosol top-of-atmosphere (TOA radiative forcing clear-sky from −0.79 to −0.53 W m−2 (33% and all-sky from −0.47 to −0.13 W m−2 (72%. Our results confirm that basic assumptions about the BC refractive index play a key role for aerosol absorption and radiative forcing. The effect of the usage of more accurate effective medium approximations is comparably small. We demonstrate that the diversity in the AeroCom land-surface albedo fields contributes to the uncertainty in the simulated anthropogenic aerosol radiative forcings: the usage of an upper versus lower bound of the AeroCom land albedos introduces a global annual-mean TOA forcing range of 0.19 W m−2 (36% clear-sky and of 0.12 W m−2 (92% all-sky. The consideration of black carbon inclusions on cloud radiative properties results in a small global annual-mean all-sky absorption of 0.05 W

  15. Absorptive capacity and smart companies

    Directory of Open Access Journals (Sweden)

    Patricia Moro González

    2014-12-01

    Full Text Available Purpose: The current competitive environment is substantially modifying the organizations’ learning processes due to a global increase of available information allowing this to be transformed into knowledge. This opportunity has been exploited since the nineties by the tools of “Business Analytics” and “Business Intelligence” but, nevertheless, being integrated in the study of new organizational capacities engaged in the process of creating intelligence inside organizations is still an outstanding task. The review of the concept of absorptive capacity and a detailed study from the perspective of this new reality will be the main objective of study of this paper.Design/methodology/approach: By comparing classical absorptive capacity and absorptive capacity from the point of view of information management tools in each one of the three stages of the organizational learning cycle, some gaps of the former are overcome/fulfilled. The academic/bibliographical references provided in this paper have been obtained from ISI web of knowledge, Scopus and Dialnet data bases, supporting the state of affairs on absorptive capacity and thereafter filtering by "Business Intelligence" and "Business Analytics". Specialized websites and Business Schools` Publications there have also been included, crowning the content on information management tools used that are currently used in the strategic consulting.Findings: Our contribution to the literature is the development of "smart absorptive capacity". This is a new capacity emerging from the reformulation of the classical concept of absorptive capacity wherein some aspects of its definition that might have been omitted are emphasized. The result of this new approach is the creation of a new Theoretical Model of Organizational Intelligence, which aims to explain, within the framework of the Resources and Capabilities Theory, the competitive advantage achieved by the so-called smart companies

  16. Decision trees to characterise the roles of permeability and solubility on the prediction of oral absorption.

    Science.gov (United States)

    Newby, Danielle; Freitas, Alex A; Ghafourian, Taravat

    2015-01-27

    Oral absorption of compounds depends on many physiological, physiochemical and formulation factors. Two important properties that govern oral absorption are in vitro permeability and solubility, which are commonly used as indicators of human intestinal absorption. Despite this, the nature and exact characteristics of the relationship between these parameters are not well understood. In this study a large dataset of human intestinal absorption was collated along with in vitro permeability, aqueous solubility, melting point, and maximum dose for the same compounds. The dataset allowed a permeability threshold to be established objectively to predict high or low intestinal absorption. Using this permeability threshold, classification decision trees incorporating a solubility-related parameter such as experimental or predicted solubility, or the melting point based absorption potential (MPbAP), along with structural molecular descriptors were developed and validated to predict oral absorption class. The decision trees were able to determine the individual roles of permeability and solubility in oral absorption process. Poorly permeable compounds with high solubility show low intestinal absorption, whereas poorly water soluble compounds with high or low permeability may have high intestinal absorption provided that they have certain molecular characteristics such as a small polar surface or specific topology. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

  17. Towards a human rotavirus disease model.

    Science.gov (United States)

    Hagbom, Marie; Sharma, Sumit; Lundgren, Ove; Svensson, Lennart

    2012-08-01

    While the clinical importance of human rotavirus (RV) disease is well recognized and potent vaccines have been developed, our understanding of how human RV causes diarrhoea, vomiting and death remains unresolved. The fact that oral rehydration corrects electrolyte and water loss, indicates that enterocytes in the small intestine have a functional sodium-glucose co-transporter. Moreover, RV infection delays gastric emptying and loperamide appears to attenuate RV diarrhoea, thereby suggesting activation of the enteric nervous system. Serotonin (5-HT) receptor antagonists attenuate vomiting in young children with gastroenteritis while zinc and enkephalinase inhibitors attenuate RV-induced diarrhoea. In this review we discuss clinical symptoms, pathology, histology and treatment practices for human RV infections and compile the data into a simplified disease model. Copyright © 2012 Elsevier B.V. All rights reserved.

  18. The impact of large tidal volume ventilation on the absorption of inhaled insulin in rabbits

    DEFF Research Database (Denmark)

    Petersen, Astrid Heide; Laursen, Torben; Ahrén, Bo

    2007-01-01

    Previous studies have shown that ventilation patterns affect absorption of inhaled compounds. Thus, the aim of this study was to investigate the effect of large tidal volume ventilation (LTVV) on the absorption of inhaled insulin in rabbits. Mechanically ventilated rabbits were given human insuli...

  19. SPECTROPHOTOMETRY OF HEMOGLOBIN - ABSORPTION-SPECTRA OF RAT OXYHEMOGLOBIN, DEOXYHEMOGLOBIN, CARBOXYHEMOGLOBIN, AND METHEMOGLOBIN

    NARCIS (Netherlands)

    ZIJLSTRA, WG; BUURSMA, A; FALKE, HE; CATSBURG, JF

    The absorptivity at 540 nm of methemoglobincyanide from rat blood was determined on the basis of iron and found to be equal to the established value for human methemoglobincyanide (11,01/mmol/cm). On this basis the absorption spectra of the common derivatives were determined for rat hemoglobin.

  20. Spectrophotometry of hemoglobin : Absorption spectra of bovine oxyhemoglobin, deoxyhemoglobin, carboxyhemoglobin, and methemoglobin

    NARCIS (Netherlands)

    Zijlstra, WG; Buursma, A

    1997-01-01

    The absorptivity at 540 nm of bovine hemiglobincyanide (cyanmethemoglobin) was determined on the basis of the iron content and found to be equal to the established value for human hemiglobincyanide (11.0 L . mmol(-1).cm(-1)). On this basis the absorption spectra of the common derivatives were

  1. MGAT2 deficiency ameliorates high-fat diet-induced obesity and insulin resistance by inhibiting intestinal fat absorption in mice.

    Science.gov (United States)

    Tsuchida, Takuma; Fukuda, Sayaka; Aoyama, Hisanori; Taniuchi, Nobuhiko; Ishihara, Tomomi; Ohashi, Noriko; Sato, Hiroko; Wakimoto, Koji; Shiotani, Masaharu; Oku, Akira

    2012-06-14

    Resynthesis of triglycerides in enterocytes of the small intestine plays a critical role in the absorption of dietary fat. Acyl-CoA:monoacylglycerol acyltransferase-2 (MGAT2) is highly expressed in the small intestine and catalyzes the synthesis of diacylglycerol from monoacylglycerol and acyl-CoA. To determine the physiological importance of MGAT2 in metabolic disorders and lipid metabolism in the small intestine, we constructed and analyzed Mgat2-deficient mice. In oral fat tolerance test (OFTT), Mgat2-deficient mice absorbed less fat into the circulation. When maintained on a high-fat diet (HFD), Mgat2-deficient mice were protected from HFD-induced obesity and insulin resistance. Heterozygote (Mgat2+/-) mice had an intermediate phenotype between Mgat2+/+ and Mgat2-/- and were partially protected from metabolic disorders. Despite of a decrease in fat absorption in the Mgat2-deficient mice, lipid levels in the feces and small intestine were comparable among the genotypes. Oxygen consumption was increased in the Mgat2-deficient mice when maintained on an HFD. A prominent upregulation of the genes involved in fatty acid oxidation was observed in the duodenum but not in the liver of the Mgat2-deficient mice. These results suggest that MGAT2 has a pivotal role in lipid metabolism in the small intestine, and the inhibition of MGAT2 activity may be a promising strategy for the treatment of obesity-related metabolic disorders.

  2. Carotenoid absorption in chicken intestine.

    Science.gov (United States)

    Gómez, R; Alonso, A; Martín, M

    1978-09-01

    The powdered flowers of marigold (Tagetes erecta) are used as a cheap source of carotenoids in avicultura. Lutein (3,3'-dyhydroxi-alpha-carotene) constitutes up to 85 to 90% of marigold carotenoids. In the plant, lutein is found esterified to palmitic or estearic acid. In chicken, carotenoid is hydrolized in the first portion of the small intestine, and absorbed as free lutein. After the absorption, lutein is not re-esterified in the different chicken tissues.

  3. Geometrical interpretation of optical absorption

    Energy Technology Data Exchange (ETDEWEB)

    Monzon, J. J.; Barriuso, A. G.; Sanchez-Soto, L. L. [Departamento de Optica, Facultad de Fisica, Universidad Complutense, E-28040 Madrid (Spain); Montesinos-Amilibia, J. M. [Departamento de Geometria y Topologia, Facultad de Matematicas, Universidad Complutense, E-28040 Madrid (Spain)

    2011-08-15

    We reinterpret the transfer matrix for an absorbing system in very simple geometrical terms. In appropriate variables, the system appears as performing a Lorentz transformation in a (1 + 3)-dimensional space. Using homogeneous coordinates, we map that action on the unit sphere, which is at the realm of the Klein model of hyperbolic geometry. The effects of absorption appear then as a loxodromic transformation, that is, a rhumb line crossing all the meridians at the same angle.

  4. On the nature of absorption

    CERN Document Server

    Barger, V; Halzen, F

    1972-01-01

    The imaginary helicity non-flip omega exchange amplitudes in KN and NN scattering are determined versus t and s from data on elastic differential cross section differences. The omega -universality prediction Im omega /sub N/(t)= 3 Im omega /sub K/(t), is found to be satisfied for 0absorptive cuts as small t preserve universality. The impact parameter distributions of the omega amplitudes show: (i) a peripheral peak centred around b approximately=1 fm, with Delta b approximately =+or-0.5 fm in KN and Delta b approximately=+or-0.75 fm in NN; (ii) a sizeable negative contribution at small b, more negative in NN than in KN, (iii) a smaller tail of negative contributions around b approximately=2 fm. Strong absorption of the omega -pole imaginary amplitude with lambda values around two is needed to reproduced this structure. A new version of the absorption model suggested by pi N amplitude analysis, is confirmed by the results. (20 refs).

  5. Topical absorption and systemic toxicity.

    Science.gov (United States)

    Alikhan, Fatima Sasha; Maibach, Howard

    2011-09-01

    Dermal absorption of some chemicals and drugs can cause systemic toxicity. We evaluated several case reports from the past decade, which discuss the dermal absorption of a specific chemical and potential local and systemic effects. We focused on herbicide and pesticide exposure along with exposure to cutaneous medication, occupational contact, and cosmeceutical exposure. Although causality cannot be established in most cases, it is critical to be aware of the possible effects of topical absorption that may not be immediately apparent. We recommended further studies on specific chemicals to ascertain causality and determine the highest exposure level with no observed adverse affect level (NOAEL) and the reference dose (RfD). Post-marketing epidemiology data in most geographical areas are markedly limited. A weak link in public health resides in the inadequate reporting and workup of alleged chemically related adverse effects. This arena mandates a re-thinking of how to increase this reporting, and workup, as a backup to our preclinical and clinical studies. Public awareness and funding will be rewarded by increased evidence to backup pre-approval pre-marketing studies.

  6. Organizational forms and knowledge absorption

    Directory of Open Access Journals (Sweden)

    Radovanović Nikola

    2016-01-01

    Full Text Available Managing the entire portion of knowledge in an organization is a challenging task. At the organizational level, there can be enormous quantities of unknown, poorly valued or inefficiently applied knowledge. This is normally followed with the underdeveloped potential or inability of organizations to absorb knowledge from external sources. Facilitation of the efficient internal flow of knowledge within the established communication network may positively affect organizational capacity to absorb or identify, share and subsequently apply knowledge to commercial ends. Based on the evidences that the adoption of different organizational forms affects knowledge flows within an organization, this research analyzed the relationship between common organizational forms and absorptive capacity of organizations. In this paper, we test the hypothesis stating that the organizational structure affects knowledge absorption and exploitation in the organization. The methodology included quantitative and qualitative research method based on a questionnaire, while the data has been statistically analyzed and the hypothesis has been tested with the use of cross-tabulation and chi-square tests. The findings suggest that the type of organizational form affects knowledge absorption capacity and that having a less formalized and more flexible structure in an organization increases absorbing and exploiting opportunities of potentially valuable knowledge.

  7. Backscatter absorption gas imaging systems and light sources therefore

    Energy Technology Data Exchange (ETDEWEB)

    Kulp, Thomas Jan [Livermore, CA; Kliner, Dahv A. V. [San Ramon, CA; Sommers, Ricky [Oakley, CA; Goers, Uta-Barbara [Campbell, NY; Armstrong, Karla M [Livermore, CA

    2006-12-19

    The location of gases that are not visible to the unaided human eye can be determined using tuned light sources that spectroscopically probe the gases and cameras that can provide images corresponding to the absorption of the gases. The present invention is a light source for a backscatter absorption gas imaging (BAGI) system, and a light source incorporating the light source, that can be used to remotely detect and produce images of "invisible" gases. The inventive light source has a light producing element, an optical amplifier, and an optical parametric oscillator to generate wavelength tunable light in the IR. By using a multi-mode light source and an amplifier that operates using 915 nm pump sources, the power consumption of the light source is reduced to a level that can be operated by batteries for long periods of time. In addition, the light source is tunable over the absorption bands of many hydrocarbons, making it useful for detecting hazardous gases.

  8. In vitro Dermal Absorption of Hydroquinone: Protocol Validation and Applicability on Illegal Skin-Whitening Cosmetics.

    Science.gov (United States)

    Desmedt, Bart; Ates, Gamze; Courselle, Patricia; De Beer, Jacques O; Rogiers, Vera; Hendrickx, Benoit; Deconinck, Eric; De Paepe, Kristien

    2016-01-01

    In Europe, hydroquinone is a forbidden cosmetic ingredient. It is, however, still abundantly used because of its effective skin-whitening properties. The question arises as to whether the quantities of hydroquinone used become systemically available and may cause damage to human health. Dermal absorption studies can provide this information. In the EU, dermal absorption has to be assessed in vitro since the Cosmetic Regulation 1223/2009/EC forbids the use of animals. To obtain human-relevant data, a Franz diffusion cell protocol was validated using human skin. The results obtained were comparable to those from a multicentre validation study. The protocol was applied to hydroquinone and the dermal absorption ranged between 31 and 44%, which is within the range of published in vivo human values. This shows that a well-validated in vitro dermal absorption study using human skin provides relevant human data. The validated protocol was used to determine the dermal absorption of illegal skin-whitening cosmetics containing hydroquinone. All samples gave high dermal absorption values, rendering them all unsafe for human health. These results add to our knowledge of illegal cosmetics on the EU market, namely that they exhibit a negative toxicological profile and are likely to induce health problems. © 2017 S. Karger AG, Basel.

  9. Mechanistic Approaches to Predicting Oral Drug Absorption

    OpenAIRE

    Huang, Weili; Lee, Sau Lawrence; Yu, Lawrence X.

    2009-01-01

    Modeling and simulation of oral drug absorption have been widely used in drug discovery, development, and regulation. Predictive absorption models are used to determine the rate and extent of oral drug absorption, facilitate lead drug candidate selection, establish formulation development strategy, and support the development of regulatory policies. This review highlights the development of recent drug absorption models including dispersion and compartmental models. The compartmental models i...

  10. Emission and Absorption Entropy Generation in Semiconductors

    OpenAIRE

    Reck, Kasper; Varpula, Aapo; Prunnila, Mika; Hansen, Ole

    2013-01-01

    While emission and absorption entropy generation is well known in black bodies, it has not previously been studied in semiconductors, even though semiconductors are widely used for solar light absorption in modern solar cells [1]. We present an analysis of the entropy generation in semiconductor materials due to emission and absorption of electromagnetic radiation. It is shown that the emission and absorption entropy generation reduces the fundamental limit on the efficiency of any semiconduc...

  11. In vitro and in vivo percutaneous absorption of retinol from cosmetic formulations: significance of the skin reservoir and prediction of systemic absorption.

    Science.gov (United States)

    Yourick, Jeffrey J; Jung, Connie T; Bronaugh, Robert L

    2008-08-15

    The percutaneous absorption of retinol (Vitamin A) from cosmetic formulations was studied to predict systemic absorption and to understand the significance of the skin reservoir in in vitro absorption studies. Viable skin from fuzzy rat or human subjects was assembled in flow-through diffusion cells for in vitro absorption studies. In vivo absorption studies using fuzzy rats were performed in glass metabolism cages for collection of urine, feces, and body content. Retinol (0.3%) formulations (hydroalcoholic gel and oil-in-water emulsion) containing (3)H-retinol were applied and absorption was measured at 24 or 72 h. All percentages reported are % of applied dose. In vitro studies using human skin and the gel and emulsion vehicles found 0.3 and 1.3% retinol, respectively, in receptor fluid at 24 h. Levels of absorption in the receptor fluid increased over 72 h with the gel and emulsion vehicles. Using the gel vehicle, in vitro rat skin studies found 23% in skin and 6% in receptor fluid at 24 h, while 72-h studies found 18% in skin and 13% in receptor fluid. Thus, significant amounts of retinol remained in rat skin at 24 h and decreased over 72 h, with proportional increases in receptor fluid. In vivo rat studies with the gel found 4% systemic absorption of retinol after 24 h and systemic absorption did not increase at 72 h. Retinol remaining in rat skin after in vivo application was 18% and 13% of the applied dermal dose after 24 and 72 h, respectively. Similar observations were made with the oil-in water emulsion vehicle in the rat. Retinol formed a reservoir in rat skin both in vivo and in vitro. Little additional retinol was bioavailable after 24 h. Comparison of these in vitro and in vivo results for absorption through rat skin indicates that the 24-h in vitro receptor fluid value accurately estimated 24-h in vivo systemic absorption. Therefore, the best single estimate of retinol systemic absorption from in vitro human skin studies is the 24-h receptor fluid

  12. Calculations ofB1Distribution, Specific Energy Absorption Rate, and Intrinsic Signal-to-Noise Ratio for a Body-Size Birdcage Coil Loaded with Different Human Subjects at 64 and 128 MHz.

    Science.gov (United States)

    Liu, W; Collins, C M; Smith, M B

    2005-03-01

    A numerical model of a female body is developed to study the effects of different body types with different coil drive methods on radio-frequency magnetic ( B 1 ) field distribution, specific energy absorption rate (SAR), and intrinsic signal-to-noise ratio (ISNR) for a body-size birdcage coil at 64 and 128 MHz. The coil is loaded with either a larger, more muscular male body model (subject 1) or a newly developed female body model (subject 2), and driven with two-port (quadrature), four-port, or many (ideal) sources. Loading the coil with subject 1 results in significantly less homogeneous B 1 field, higher SAR, and lower ISNR than those for subject 2 at both frequencies. This dependence of MR performance and safety measures on body type indicates a need for a variety of numerical models representative of a diverse population for future calculations. The different drive methods result in similar B 1 field patterns, SAR, and ISNR in all cases.

  13. Relationships between absorption efficiency of elements in mammals and chemical properties.

    Science.gov (United States)

    Le, T T Yen; Hendriks, A Jan

    2013-10-01

    Oral absorption efficiency is an important factor to consider in human risk assessment and varies widely between elements. Linking absorption efficiency to chemical properties facilitates the understanding of underlying processes and enables extrapolation across elements. In our study, oral absorption efficiency in humans was predicted for a number of elements based on their ionization energy and electronegativity. Data on oral absorption efficiency in humans were retrieved via a literature survey. A model was developed based on the assumption that ionic species readily react with biotic ligands. Accordingly, ionization energy was presumed to represent the reactivity and absorption of atoms in the gastrointestinal tract. The coefficients of the model were parameterized by fitting the quantitative relationship between absorption efficiency and ionization energy to data collected from well-standardized studies. Generally, absorption efficiency was strongly related to ionization energy, explaining 94% of the variability in absorption efficiency between elements reported by the International Commission on Radiological Protection (ICRP). In addition, the absorption efficiencies predicted based on ionization energy were within a factor of two of those given by the ICRP (ME = -0.05; RMSE = 0.31). However, the model is not applicable to alkaline metals and molybdenum because of the uniquely high solubility of their compounds or the flexible electron configuration of these elements. Approximately 56% of the variability in absorption efficiency between elements could be explained by electronegativity. These strong relationships between absorption efficiency and ionization energy and, to a lesser extent, electronegativity indicate potential for extrapolation across elements using atomic properties.

  14. Normalizing genes for quantitative RT-PCR in differentiating human intestinal epithelial cells and adenocarcinomas of the colon.

    Science.gov (United States)

    Dydensborg, Anders Bondo; Herring, Elizabeth; Auclair, Joëlle; Tremblay, Eric; Beaulieu, Jean-Francois

    2006-05-01

    As for other mRNA measurement methods, quantitative RT-PCR results need to be normalized relative to stably expressed genes. Widely used normalizing genes include beta-actin and glyceraldehyde-3-phosphate dehydrogenase. It has, however, become clear that these and other normalizing genes can display modulated patterns of expression across tissue types and during complex cellular processes such as cell differentiation and cancer progression. Our objective was to set the basis for identifying normalizing genes that displayed stable expression during enterocytic differentiation and between healthy tissue and adenocarcinomas of the human colon. We thus identified novel potential normalizing genes using previously generated cDNA microarray data and examined the alterations of expression of two of these genes as well as seven commonly used normalizing genes during the enterocytic differentiation process and between matched pairs of resection margins and primary carcinomas of the human colon using real-time RT-PCR. We found that ribosomal phosphoprotein P0 was particularly stable in all intestinal epithelial cell extracts, thereby representing a particularly robust housekeeping reference gene for the assessment of gene expression during the human enterocytic differentiation process. On the other hand, beta-2-microglobulin generated the best score as a normalizing gene for comparing human colon primary carcinomas with their corresponding normal mucosa of the resection margin, although others were found to represent acceptable alternatives. In conclusion, we identified and characterized specific normalizing genes that should significantly improve quantitative mRNA studies related to both the differentiation process of the human intestinal epithelium and adenocarcinomas of the human colon. This approach should also be useful to validate normalizing genes in other intestinal contexts.

  15. Stimulation of Apolipoprotein A-IV expression in Caco-2/TC7 enterocytes and reduction of triglyceride formation in 3T3-L1 adipocytes by potential anti-obesity Chinese herbal medicines

    Directory of Open Access Journals (Sweden)

    Guo Ava

    2009-03-01

    Full Text Available Abstract Background Chinese medicine has been proposed as a novel strategy for the prevention of metabolic disorders such as obesity. The present study tested 17 Chinese medicinal herbs were tested for their potential anti-obesity effects. Methods The herbs were evaluated in terms of their abilities to stimulate the transcription of Apolipoprotein A-IV (ApoA-IV in cultured Caco-2/TC7 enterocytes. The herbs that showed stimulating effects on ApoA-IV transcription were further evaluated in terms of their abilities to reduce the formation of triglyceride in differentiated 3T3-L1 adipocytes. Results ApoA-IV transcription was stimulated by Rhizoma Alismatis and Radix Angelica Sinensis in a dose- and time-dependent manner in cultured Caco-2/TC7 cells. Moreover, these two herbs reduced the amount of triglyceride in differentiated 3T3-L1 adipocytes. Conclusion The results suggest that Rhizoma Alistmatis and Radix Angelica Sinensis may have potential anti-obesity effects as they stimulate ApoA-IV transcription and reduce triglyceride formation.

  16. Carbon Dioxide Absorption Heat Pump

    Science.gov (United States)

    Jones, Jack A. (Inventor)

    2002-01-01

    A carbon dioxide absorption heat pump cycle is disclosed using a high pressure stage and a super-critical cooling stage to provide a non-toxic system. Using carbon dioxide gas as the working fluid in the system, the present invention desorbs the CO2 from an absorbent and cools the gas in the super-critical state to deliver heat thereby. The cooled CO2 gas is then expanded thereby providing cooling and is returned to an absorber for further cycling. Strategic use of heat exchangers can increase the efficiency and performance of the system.

  17. Correction by 1-25-dihydroxycholecalciferol of the abnormal fluidity and lipid composition of enterocyte brush border membranes in vitamin D-deprived rats.

    Science.gov (United States)

    Brasitus, T A; Dudeja, P K; Eby, B; Lau, K

    1986-12-15

    Weanling male Wistar rats were deprived of dietary and light sources of vitamin D for 11-18 weeks along with age-matched diet vitamin D-repleted controls to evaluate the role of lipid fluidity in the stimulatory effect of calcitriol on Ca transport. The "static" component of fluidity of proximal small intestine brush border membrane, as assessed by steady-state fluorescence techniques using the fluorophore 1,6-diphenyl-1,3,5-hexatriene, was similar between these two groups. In contrast, the "dynamic" component of fluidity, as assessed by DL-2-(9-anthroyl)-stearic acid and DL-12-(9-anthroyl)-stearic acid, was decreased in membranes of D-deprived animals. Lipid composition was analyzed to evaluate the potential mechanism mediating these fluidity changes. In vitamin D-deprived rats, linoleic (18:2) and arachidonic (20:4) acids of the phosphatidylcholine and phosphatidylethanolamine fractions of the membrane were decreased, whereas palmitic (16:0) and stearic (18:0) acids were increased in the phosphatidylethanolamine fraction of the membrane. These associated fatty acyl alterations could explain, at least in part, the differences in membrane fluidity between D-repleted and D-deprived rats. Membrane fluidity, lipid composition, and duodenal Ca transport were also analyzed 1, 2, and 5 h after the acute administration of 1-25-dihydroxycholecalciferol to D-deprived animals. In D-deprived rats, within 1-2 h, this hormone restored to levels of vitamin D-repleted controls the dynamic component of fluidity and concentrations of the same membrane phospholipid fatty acids. Since these changes temporally precede detectable increases in Ca absorption (demonstrable only during the 5th h), these data support the hypothesis that alterations in membrane fluidity and lipid composition may play an important role in the stimulation of intestinal calcium transport by calcitriol.

  18. Iodine Absorption Cells Purity Testing

    Directory of Open Access Journals (Sweden)

    Jan Hrabina

    2017-01-01

    Full Text Available This article deals with the evaluation of the chemical purity of iodine-filled absorption cells and the optical frequency references used for the frequency locking of laser standards. We summarize the recent trends and progress in absorption cell technology and we focus on methods for iodine cell purity testing. We compare two independent experimental systems based on the laser-induced fluorescence method, showing an improvement of measurement uncertainty by introducing a compensation system reducing unwanted influences. We show the advantages of this technique, which is relatively simple and does not require extensive hardware equipment. As an alternative to the traditionally used methods we propose an approach of hyperfine transitions’ spectral linewidth measurement. The key characteristic of this method is demonstrated on a set of testing iodine cells. The relationship between laser-induced fluorescence and transition linewidth methods will be presented as well as a summary of the advantages and disadvantages of the proposed technique (in comparison with traditional measurement approaches.

  19. Circumgalactic Oxygen Absorption and Feedback

    Science.gov (United States)

    Mathews, William G.; Prochaska, J. Xavier

    2017-09-01

    O vi absorption in quasar spectra caused by intervening circumgalactic atmospheres suggests a downturn in the atmospheric column density in sightlines passing beyond about 100 kpc from central star-forming galaxies. This turnover supports the hypothesis that the oxygen originates in the central galaxies. When converted into oxygen space density using an Abel integral inversion, the O vi columns require ≳ {10}9 M ⊙ of oxygen concentrated near 100 kpc. Circumgalactic gas within this radius cools in less than 1 Gyr and radiates ˜ {10}42.2 erg s-1 overall. The feedback power necessary to maintain such oxygen-rich atmospheres for many Gyr cannot be easily supplied by galactic supernovae. However, massive central black holes in star-forming galaxies may generate sufficient accretion power and intermittent shock waves at r˜ 100 {kpc} to balance circumgalactic radiation losses in late-type {L}\\star galaxies. The relative absence of O vi absorption observed in early-type, passive {L}\\star galaxies may arise from enhanced AGN feedback from their more massive central black holes.

  20. Iron Absorption in Drosophila melanogaster

    Directory of Open Access Journals (Sweden)

    Fanis Missirlis

    2013-05-01

    Full Text Available The way in which Drosophila melanogaster acquires iron from the diet remains poorly understood despite iron absorption being of vital significance for larval growth. To describe the process of organismal iron absorption, consideration needs to be given to cellular iron import, storage, export and how intestinal epithelial cells sense and respond to iron availability. Here we review studies on the Divalent Metal Transporter-1 homolog Malvolio (iron import, the recent discovery that Multicopper Oxidase-1 has ferroxidase activity (iron export and the role of ferritin in the process of iron acquisition (iron storage. We also describe what is known about iron regulation in insect cells. We then draw upon knowledge from mammalian iron homeostasis to identify candidate genes in flies. Questions arise from the lack of conservation in Drosophila for key mammalian players, such as ferroportin, hepcidin and all the components of the hemochromatosis-related pathway. Drosophila and other insects also lack erythropoiesis. Thus, systemic iron regulation is likely to be conveyed by different signaling pathways and tissue requirements. The significance of regulating intestinal iron uptake is inferred from reports linking Drosophila developmental, immune, heat-shock and behavioral responses to iron sequestration.

  1. Iron Absorption in Drosophila melanogaster

    Science.gov (United States)

    Mandilaras, Konstantinos; Pathmanathan, Tharse; Missirlis, Fanis

    2013-01-01

    The way in which Drosophila melanogaster acquires iron from the diet remains poorly understood despite iron absorption being of vital significance for larval growth. To describe the process of organismal iron absorption, consideration needs to be given to cellular iron import, storage, export and how intestinal epithelial cells sense and respond to iron availability. Here we review studies on the Divalent Metal Transporter-1 homolog Malvolio (iron import), the recent discovery that Multicopper Oxidase-1 has ferroxidase activity (iron export) and the role of ferritin in the process of iron acquisition (iron storage). We also describe what is known about iron regulation in insect cells. We then draw upon knowledge from mammalian iron homeostasis to identify candidate genes in flies. Questions arise from the lack of conservation in Drosophila for key mammalian players, such as ferroportin, hepcidin and all the components of the hemochromatosis-related pathway. Drosophila and other insects also lack erythropoiesis. Thus, systemic iron regulation is likely to be conveyed by different signaling pathways and tissue requirements. The significance of regulating intestinal iron uptake is inferred from reports linking Drosophila developmental, immune, heat-shock and behavioral responses to iron sequestration. PMID:23686013

  2. In silico predictions of gastrointestinal drug absorption in pharmaceutical product development: application of the mechanistic absorption model GI-Sim.

    Science.gov (United States)

    Sjögren, Erik; Westergren, Jan; Grant, Iain; Hanisch, Gunilla; Lindfors, Lennart; Lennernäs, Hans; Abrahamsson, Bertil; Tannergren, Christer

    2013-07-16

    Oral drug delivery is the predominant administration route for a major part of the pharmaceutical products used worldwide. Further understanding and improvement of gastrointestinal drug absorption predictions is currently a highly prioritized area of research within the pharmaceutical industry. The fraction absorbed (fabs) of an oral dose after administration of a solid dosage form is a key parameter in the estimation of the in vivo performance of an orally administrated drug formulation. This study discloses an evaluation of the predictive performance of the mechanistic physiologically based absorption model GI-Sim. GI-Sim deploys a compartmental gastrointestinal absorption and transit model as well as algorithms describing permeability, dissolution rate, salt effects, partitioning into micelles, particle and micelle drifting in the aqueous boundary layer, particle growth and amorphous or crystalline precipitation. Twelve APIs with reported or expected absorption limitations in humans, due to permeability, dissolution and/or solubility, were investigated. Predictions of the intestinal absorption for different doses and formulations were performed based on physicochemical and biopharmaceutical properties, such as solubility in buffer and simulated intestinal fluid, molecular weight, pK(a), diffusivity and molecule density, measured or estimated human effective permeability and particle size distribution. The performance of GI-Sim was evaluated by comparing predicted plasma concentration-time profiles along with oral pharmacokinetic parameters originating from clinical studies in healthy individuals. The capability of GI-Sim to correctly predict impact of dose and particle size as well as the in vivo performance of nanoformulations was also investigated. The overall predictive performance of GI-Sim was good as >95% of the predicted pharmacokinetic parameters (C(max) and AUC) were within a 2-fold deviation from the clinical observations and the predicted plasma AUC

  3. A comparative study of the PIFA and printed monopole antenna EM absorption.

    Science.gov (United States)

    Hossain, Md Ikbal; Iqbal Faruque, Mohammad Rashed; Islam, Mohammad Tariqul

    2017-02-01

    This paper represents a comparative study on electromagnetic (EM) absorption in the human head between a printed monopole antenna and a planar inverted-F antenna (PIFA). The specific absorption rate (SAR) values and total absorbed power in the human head phantom are used to evaluate EM absorption for both antennae. Moreover, antenna performances in terms of return loss, radiation efficiency, and gain are also investigated in this study. The finite integration technique (FIT) based on CST Microwave studio and SAM head phantom are used in this study. The antenna performances are measured in an anechoic chamber and the SAR is tested using COMOSAR measurement system. The obtained results indicate that the printed monopole antenna lead to higher EM absorption in the human head as compared to PIFA for both GSM frequencies.

  4. Sound absorption with green materials

    Science.gov (United States)

    Trematerra, Amelia; Lombardi, Ilaria

    2017-07-01

    Green materials are a valid alternative to traditional materials that are by-products of processing oil. At the end of their useful life, green materials can be disposed of without polluting the environment. They are now being used in the construction and automotive industries. While, studies are currently being carried out in the aviation sector on the use of green materials for non-structural components of airplanes. Green materials can be used to improve the acoustic comfort inside buildings as well as mitigate reverberation, echoes effects and reduce the transmission of noise between rooms. In this paper, the acoustic measurements of the properties of green materials are reported. The absorption coefficient of samples of the materials were measured in the frequency range from 200 Hz to 2,000 Hz with an impedance tube, with the flow resistance being measured.

  5. HI Absorption in Merger Remnants

    Science.gov (United States)

    Teng, Stacy H.; Veileux, Sylvain; Baker, Andrew J.

    2012-01-01

    It has been proposed that ultraluminous infrared galaxies (ULIRGs) pass through a luminous starburst phase, followed by a dust-enshrouded AGN phase, and finally evolve into optically bright "naked" quasars once they shed their gas/dust reservoirs through powerful wind events. We present the results of our recent 21- cm HI survey of 21 merger remnants with the Green Bank Telescope. These remnants were selected from the QUEST (Quasar/ULIRG Evolution Study) sample of ULIRGs and PG quasars; our targets are all bolometrically dominated by AGN and sample all phases of the proposed ULIRG -> IR-excess quasar -> optical quasar sequence. We explore whether there is an evolutionary connection between ULIRGs and quasars by looking for the occurrence of HI absorption tracing neutral gas outflows; our results will allow us to identify where along the sequence the majority of a merger's gas reservoir is expelled.

  6. X-ray absorption spectroscopic studies of zinc in the N-terminal domain of HIV-2 integrase and model compounds

    NARCIS (Netherlands)

    Feiters, M.C.; Eijkelenboom, A.; Nolting, H.-F.; Krebs, B.; van den Ent, F.M.I.; Plasterk, R.H.A.; Kaptein, R.; Boelens, R.

    2003-01-01

    X-ray absorption spectroscopy (XAS), including extended X-ray absorption fine structure (EXAFS) and X-ray absorption near-edge structure (XANES) analysis, has been carried out at the Zn K edge of the N-terminal part of the integrase protein of the human immunodeficiency virus, type 2 (HIV-2), and of

  7. Immunological quantitation and localization of ACAT-1 and ACAT-2 in human liver and small intestine.

    Science.gov (United States)

    Chang, C C; Sakashita, N; Ornvold, K; Lee, O; Chang, E T; Dong, R; Lin, S; Lee, C Y; Strom, S C; Kashyap, R; Fung, J J; Farese, R V; Patoiseau, J F; Delhon, A; Chang, T Y

    2000-09-08

    By using specific anti-ACAT-1 antibodies in immunodepletion studies, we previously found that ACAT-1, a 50-kDa protein, plays a major catalytic role in the adult human liver, adrenal glands, macrophages, and kidneys but not in the intestine. Acyl-coenzyme A:cholesterol acyltransferase (ACAT) activity in the intestine may be largely derived from a different ACAT protein. To test this hypothesis, we produced specific polyclonal anti-ACAT-2 antibodies that quantitatively immunodepleted human ACAT-2, a 46-kDa protein expressed in Chinese hamster ovary cells. In hepatocyte-like HepG2 cells, ACAT-1 comprises 85-90% of the total ACAT activity, with the remainder attributed to ACAT-2. In adult intestines, most of the ACAT activity can be immunodepleted by anti-ACAT-2. ACAT-1 and ACAT-2 do not form hetero-oligomeric complexes. In differentiating intestinal enterocyte-like Caco-2 cells, ACAT-2 protein content increases by 5-10-fold in 6 days, whereas ACAT-1 protein content remains relatively constant. In the small intestine, ACAT-2 is concentrated at the apices of the villi, whereas ACAT-1 is uniformly distributed along the villus-crypt axis. In the human liver, ACAT-1 is present in both fetal and adult hepatocytes. In contrast, ACAT-2 is evident in fetal but not adult hepatocytes. Our results collectively suggest that in humans, ACAT-2 performs significant catalytic roles in the fetal liver and in intestinal enterocytes.

  8. Absorption boundary conditions for geomertical acoustics

    DEFF Research Database (Denmark)

    Jeong, Cheol-Ho

    2012-01-01

    Defining accurate acoustical boundary conditions is of crucial importance for room acoustic simulations. In predicting sound fields using phased geometrical acoustics methods, the absorption coefficients or surface impedances of the boundary surfaces can be used, but no guideline has been developed...... solutions. Two rectangular rooms with uniform and non-uniform absorption distributions are tested. It is concluded that the impedance and random incidence absorption boundary conditions produce reasonable results with some exceptions at low frequencies for acoustically soft materials....

  9. Vitamin B12 absorption from eggs.

    Science.gov (United States)

    Doscherholmen, A; McMahon, J; Ripley, D

    1975-09-01

    The assimilation of 57Co B12 from in vivo labeled eggs was much inferior to that of a comparable amount of crystalline 57Co B12. Furthermore, the absorption varied with the form in which the eggs were served. Judged by the urinary excretion test and the plasma absorption of radioactivity the average absorption from boiled and fried eggs was more than twice that from scrambled whole eggs, but less than half that absorbed from crystalline 57Co B12.

  10. Worldwide survey of absorption fluids data

    Energy Technology Data Exchange (ETDEWEB)

    Macriss, R.A.; Zawacki, T.S.

    1988-01-01

    The overall objective of this study is to develop improved data for the thermodynamic, transport and physical properties of absorption fluids. A specific objective of this phase of the study is to compile, catalog and coarse-screen the available worldwide data of known absorption fluid systems and publish it as a reference document to be distributed to manufacturers, researchers and others active in absorption heat pump activities. 3 refs., 3 figs., 1 tab.

  11. Effects of Omeprazole on Iron Absorption: Preliminary Study

    Directory of Open Access Journals (Sweden)

    Mahmut Yaşar Çeliker

    2013-09-01

    Full Text Available Objective: Increasing numbers of pediatric and adult patients are being treated with proton pump inhibitors (PPIs. PPIs are known to inhibit gastric acid secretion. Nonheme iron requires gastric acid for conversion to the ferrous form for absorption. Ninety percent of dietary and 100% of oral iron therapy is in the nonheme form. To the best of our knowledge, the effect of PPIs on iron absorption has not been studied in humans. Our study assessed the relationship between omeprazole therapy and iron absorption in healthy subjects. Materials and Methods: We recruited 9 healthy volunteers between June 2010 and March 2011. Subjects with chronic illness, anemia, or use of PPI therapy were excluded. Serum iron concentrations were measured 1, 2, and 3 h after the ingestion of iron (control group. The measurements were repeated on a subsequent visit after 4 daily oral administrations of omeprazole at a dose of 40 mg (treatment group. Results: One female and 8 male volunteers were enrolled in the study with a mean age of 33 years. There was no statistical difference detected between baseline, 1-h, 2-h, and 3-h iron levels between control and treatment groups. Conclusion: Administration of omeprazole for a short duration does not affect absorption of orally administered iron in healthy individuals.

  12. Physiological Importance and Mechanisms of Protein Hydrolysate Absorption

    Science.gov (United States)

    Zhanghi, Brian M.; Matthews, James C.

    Understanding opportunities to maximize the efficient digestion and assimilation by production animals of plant- and animal-derived protein products is critical for farmers, nutritionists, and feed manufacturers to sustain and expand the affordable production of high quality animal products for human consumption. The challenge to nutritionists is to match gastrointestinal tract load to existing or ­inducible digestive and absorptive capacities. The challenge to feed manufacturers is to develop products that are efficient substrates for digestion, absorption, and/or both events. Ultimately, the efficient absorption of digesta proteins depends on the mediated passage (transport) of protein hydrosylate products as dipeptides and unbound amino acids across the lumen- and blood-facing membranes of intestinal absorptive cells. Data testing the relative efficiency of supplying protein as hydrolysates or specific dipeptides versus as free amino acids, and the response of animals in several physiological states to feeding of protein hydrolysates, are presented and reviewed in this chapter. Next, data describing the transport mechanisms responsible for absorbing protein hydrolysate digestion products, and the known and putative regulation of these mechanisms by their substrates (small peptides) and hormones are presented and reviewed. Several conclusions are drawn regarding the efficient use of protein hydrolysate-based diets for particular physiological states, the economically-practical application of which likely will depend on technological advances in the manufacture of protein hydrolysate products.

  13. Detection of human norovirus in intestinal biopsies from immunocompromised transplant patients.

    Science.gov (United States)

    Karandikar, Umesh C; Crawford, Sue E; Ajami, Nadim J; Murakami, Kosuke; Kou, Baijun; Ettayebi, Khalil; Papanicolaou, Genovefa A; Jongwutiwes, Ubonvan; Perales, Miguel-Angel; Shia, Jinru; Mercer, David; Finegold, Milton J; Vinjé, Jan; Atmar, Robert L; Estes, Mary K

    2016-09-01

    Human noroviruses (HuNoVs) can often cause chronic infections in solid organ and haematopoietic stem cell transplant (HSCT) patients. Based on histopathological changes observed during HuNoV infections, the intestine is the presumed site of virus replication in patients; however, the cell types infected by HuNoVs remain unknown. The objective of this study was to characterize histopathological changes during HuNoV infection and to determine the cell types that may be permissive for HuNoV replication in transplant patients. We analysed biopsies from HuNoV-infected and non-infected (control) transplant patients to assess histopathological changes in conjunction with detection of HuNoV antigens to identify the infected cell types. HuNoV infection in immunocompromised patients was associated with histopathological changes such as disorganization and flattening of the intestinal epithelium. The HuNoV major capsid protein, VP1, was detected in all segments of the small intestine, in areas of biopsies that showed histopathological changes. Specifically, VP1 was detected in enterocytes, macrophages, T cells and dendritic cells. HuNoV replication was investigated by detecting the non-structural proteins, RdRp and VPg. We detected RdRp and VPg along with VP1 in duodenal and jejunal enterocytes. These results provide critical insights into histological changes due to HuNoV infection in immunocompromised patients and propose human enterocytes as a physiologically relevant cell type for HuNoV cultivation.

  14. Differential Photoacoustic Particle Absorption Monitor Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We developed a highly sensitive and compact instrument to directly measure particulate matter (PM) optical absorption. This device is based on differential...

  15. Absorption bands in the spectrum of Io

    Science.gov (United States)

    Cruikshank, D. P.; Jones, T. J.; Pilcher, C. B.

    1978-01-01

    Near-infrared spectra of Io in the region from 2.8 to 4.2 microns are reported which show distinct absorption features, the most notable at 4.1 microns. Frozen volatiles or atmospheric gases cannot account for these absorptions, nor do they resemble those seen in common silicate rocks. Several candidate substances, most notably nitrate and carbonate salts, show absorption features in this spectral region; the deepest band in the spectrum may be a nitrate absorption. The satellite surface is shown to be anhydrous, as indicated by the absence of the 3-micron bound water band.

  16. Hfq and three Hfq-dependent small regulatory RNAs-MgrR, RyhB and McaS-coregulate the locus of enterocyte effacement in enteropathogenic Escherichia coli.

    Science.gov (United States)

    Bhatt, Shantanu; Egan, Marisa; Ramirez, Jasmine; Xander, Christian; Jenkins, Valerie; Muche, Sarah; El-Fenej, Jihad; Palmer, Jamie; Mason, Elisabeth; Storm, Elizabeth; Buerkert, Thomas

    2017-02-01

    Enteropathogenic Escherichia coli (EPEC) is a significant cause of infantile diarrhea and death in developing countries. The pathogenicity island locus of enterocyte effacement (LEE) is essential for EPEC to cause diarrhea. Besides EPEC, the LEE is also present in other gastrointestinal pathogens, most notably enterohemorrhagic E. coli (EHEC). Whereas transcriptional control of the LEE has been meticulously examined, posttranscriptional regulation, including the role of Hfq-dependent small RNAs, remains undercharacterized. However, the past few years have witnessed a surge in the identification of riboregulators of the LEE in EHEC. Contrastingly, the posttranscriptional regulatory landscape of EPEC remains cryptic. Here we demonstrate that the RNA-chaperone Hfq represses the LEE of EPEC by targeting the 5' untranslated leader region of grlR in the grlRA mRNA. Three conserved small regulatory RNAs (sRNAs)-MgrR, RyhB and McaS-are involved in the Hfq-dependent regulation of grlRA MgrR and RyhB exert their effects by directly base-pairing to the 5' region of grlR Whereas MgrR selectively represses grlR but activates grlA, RyhB represses gene expression from the entire grlRA transcript. Meanwhile, McaS appears to target the grlRA mRNA indirectly. Thus, our results provide the first definitive evidence that implicates multiple sRNAs in regulating the LEE and the resulting virulence of EPEC. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  17. Systemic absorption of the sunscreens benzophenone-3, octyl-methoxycinnamate, and 3-(4-methyl-benzylidene) camphor after whole-body topical application and reproductive hormone levels in humans

    DEFF Research Database (Denmark)

    Janjua, Nadeem Rezaq; Mogensen, Brian; Andersson, Anna-Maria

    2004-01-01

    reproductive hormone levels in humans after topical application. In this 2-wk single-blinded study 32 healthy volunteers, 15 young males and 17 postmenopausal females, were assigned to daily whole-body topical application of 2 mg per cm(2) of basic cream formulation without (week 1) and with (week 2) the three...... sunscreens at 10% (wt/wt) of each. Maximum plasma concentrations were 200 ng per mL BP-3, 20 ng per mL 4-MBC, and 10 ng per mL OMC for females and 300 ng per mL BP-3, 20 ng per mL 4-MBC, and 20 ng per mL OMC for men. All three sunscreens were detectable in urine. The reproductive hormones FSH, LH were...

  18. Numerical evaluation of image homogeneity, signal-to-noise ratio, and specific absorption rate for human brain imaging at 1.5, 3, 7, 10.5, and 14T in an 8-channel transmit/receive array.

    Science.gov (United States)

    Cao, Zhipeng; Park, Joshua; Cho, Zang-Hee; Collins, Christopher M

    2015-05-01

    To predict signal-to-noise ratio (SNR) trends and absorbed energy in magnetic resonance imaging (MRI) of the brain up to 14T. A human head in an eight-channel transmit/receive coil was simulated with Maxwell and Bloch equations to determine excitation homogeneity with radiofrequency (RF) shimming, image homogeneity, SNR, and absorbed energy in MRI from 1.5 to 14T considering realistic field distributions and relaxation properties. RF shimming alone achieved a standard deviation in excitation flip angle less than 10° in mid-brain up to 14T, but produced a small region with low excitation on a lower slice. Current reconstruction methods may produce shading artifacts at 14T. SNR increases with a greater-than-linear rate for gradient recalled echo (GRE) sequences having short (2 msec) echo time (TE) and long relaxation time (TR) (∼2.3-fold increase from 7T to 14T), but a less-than-linear rate if TE is 10 msec (∼1.6-fold increase from 7T to 14T). Depending on the sequence, SNR per square root of imaging time may produce a less-than-linear increase with B0 . Whole-head absorbed energy shows a less-than-quadratic increase with B0 (1.7-fold increase from 7T to 14T). Numerical simulations indicate that with proper preparation and precautions, imaging of the human brain at up to 14T could be performed safely, with advantages in SNR. © 2014 Wiley Periodicals, Inc.

  19. Dermal absorption of a dilute aqueous solution of malathion

    Directory of Open Access Journals (Sweden)

    Scharf John

    2008-01-01

    Full Text Available Malathion is an organophosphate pesticide commonly used on field crops, fruit trees, livestock, agriculture, and for mosquito and medfly control. Aerial applications can result in solubilized malathion in swimming pools and other recreational waters that may come into contact with human skin. To evaluate the human skin absorption of malathion for the assessment of risk associated with human exposures to aqueous solutions, human volunteers were selected and exposed to aqueous solutions of malathion. Participants submerged their arms and hands in twenty liters of dilute malathion solution in either a stagnant or stirred state. The "disappearance method" was applied by measuring malathion concentrations in the water before and after human exposure for various periods of time. No measurable skin absorption was detected in 42% of the participants; the remaining 58% of participants measured minimal absorbed doses of malathion. Analyzing these results through the Hazard Index model for recreational swimmer and bather exposure levels typically measured in contaminated swimming pools and surface waters after bait application indicated that these exposures are an order of magnitude less than a minimal dose known to result in a measurable change in acetylcholinesterase activity. It is concluded that exposure to aqueous malathion in recreational waters following aerial bait applications is not appreciably absorbed, does not result in an effective dose, and therefore is not a public health hazard.

  20. Use of Antibody Responses against Locus of Enterocyte Effacement (LEE)-Encoded Antigens To Monitor Enterohemorrhagic Escherichia coli Infections on Cattle Farms

    Science.gov (United States)

    Joris, Maria-Adelheid; Vanrompay, Daisy; Verstraete, Karen; De Reu, Koen; De Zutter, Lieven

    2013-01-01

    Enterohemorrhagic Escherichia coli (EHEC) is a significant zoonotic pathogen causing severe disease associated with watery and bloody diarrhea, hemorrhagic colitis, and the hemolytic-uremic syndrome (HUS) in humans. Infections are frequently associated with contact with EHEC-contaminated ruminant feces. Both natural and experimental infection of cattle induces serum antibodies against the LEE-encoded proteins intimin, EspA, EspB, and Tir and the Shiga toxins Stx1 and Stx2, although the latter are poorly immunogenic in cattle. We determined whether antibodies and/or the kinetics of antibody responses against intimin, Tir, EspA, and/or EspB can be used for monitoring EHEC infections in beef cattle herds in order to reduce carcass contamination at slaughter. We examined the presence of serum antibodies against recombinant O157:H7 E. coli intimin EspA, EspB, and Tir during a cross-sectional study on 12 cattle farms and during a longitudinal time course study on two EHEC-positive cattle farms. We searched for a possible correlation between intimin, Tir, EspA, and/or EspB antibodies and fecal excretion of EHEC O157, O145, O111, O103, or O26 seropathotypes. The results indicated that serum antibody responses to EspB and EspA might be useful for first-line screening at the herd level for EHEC O157, O26, and most likely also for EHEC O103 infections. However, antibody responses against EspB are of less use for monitoring individual animals, since some EHEC-shedding animals did not show antibody responses and since serum antibody responses against EspB could persist for several months even when shedding had ceased. PMID:23563950

  1. Annette Bunge: developing the principles in percutaneous absorption using chemical engineering principles.

    Science.gov (United States)

    Stinchcomb, A L

    2013-01-01

    Annette Bunge and her research group have had the central theme of mathematically modeling the dermal absorption process. Most of the research focus has been on estimating dermal absorption for the purpose of risk assessment, for exposure scenarios in the environment and in the occupational setting. Her work is the basis for the United States Environmental Protection Agency's estimations for dermal absorption from contaminated water. It is also the basis of the dermal absorption estimates used in determining if chemicals should be assigned a 'skin notation' for potential systemic toxicity following occupational skin exposure. The work is truly translational in that it started with mathematical theory, is validated with preclinical and human experiments, and then is used in guidelines to protect human health. Her valued research has also extended into the topical drug bioavailability and bioequivalence assessment field.

  2. Absorption of ozone by porous particles

    Energy Technology Data Exchange (ETDEWEB)

    Afanas' ev, V.P.; Dorofeev, S.B.; Sinitsyn, V.I.; Smirnov, B.M.

    1981-11-01

    The absorption of ozone by porous zeolite, silica gel, and activated carbon particles has been studied experimentally. It was shown that in addition to absorption, dissociation of ozone on the surface plays an important and sometimes decisive role. The results obtained were used to analyze the nature of ball lightning.

  3. Scalar absorption by charged rotating black holes

    Science.gov (United States)

    Leite, Luiz C. S.; Benone, Carolina L.; Crispino, Luís C. B.

    2017-08-01

    We compute numerically the absorption cross section of planar massless scalar waves impinging upon a Kerr-Newman black hole with different incidence angles. We investigate the influence of the black hole electric charge and angular momentum in the absorption spectrum, comparing our numerical computations with analytical results for the limits of high and low frequency.

  4. High-Absorptance Radiative Heat Sink

    Science.gov (United States)

    Cafferty, T.

    1983-01-01

    Absorptance of black-painted open-cell aluminum honeycomb improved by cutting honeycomb at angle or bias rather than straight across. This ensures honeycomb cavities escapes. At each reflection radiation attenuated by absorption. Applications include space-background simulators, space radiators, solar absorbers, and passive coolers for terrestrial use.

  5. Ultrafast THz Saturable Absorption in Semiconductors

    DEFF Research Database (Denmark)

    Turchinovich, Dmitry; Hoffmann, Matthias C.

    2011-01-01

    We demonstrate THz saturable absorption in n-doped semiconductors GaAs, GaP, and Ge in a nonlinear THz time-domain spectroscopy experiment. Saturable absorption is caused by sample conductivity modulation due to electron heating and satellite valley scattering in the field of a strong THz pulse....

  6. Absorption, bioavailability and metabolism of flavonoids

    NARCIS (Netherlands)

    Hollman, P.C.H.

    2004-01-01

    To unravel mechanisms of action of dietary flavonoids in their potential role in disease prevention, it is crucial to know the factors that determine their release from foods, their extent of absorption, and their fate in the organism. Research on absorption, metabolism, and bioavailability of

  7. Emission and Absorption Entropy Generation in Semiconductors

    DEFF Research Database (Denmark)

    Reck, Kasper; Varpula, Aapo; Prunnila, Mika

    2013-01-01

    materials due to emission and absorption of electromagnetic radiation. It is shown that the emission and absorption entropy generation reduces the fundamental limit on the efficiency of any semiconductor solar cell even further than the Landsberg limit. The results are derived from purely thermodynamical...

  8. Atmospheric Solar Heating in Minor Absorption Bands

    Science.gov (United States)

    Chou, Ming-Dah

    1998-01-01

    Solar radiation is the primary source of energy driving atmospheric and oceanic circulations. Concerned with the huge computing time required for computing radiative transfer in weather and climate models, solar heating in minor absorption bands has often been neglected. The individual contributions of these minor bands to the atmospheric heating is small, but collectively they are not negligible. The solar heating in minor bands includes the absorption due to water vapor in the photosynthetically active radiation (PAR) spectral region from 14284/cm to 25000/cm, the ozone absorption and Rayleigh scattering in the near infrared, as well as the O2 and CO2 absorption in a number of weak bands. Detailed high spectral- and angular-resolution calculations show that the total effect of these minor absorption is to enhance the atmospheric solar heating by approximately 10%. Depending upon the strength of the absorption and the overlapping among gaseous absorption, different approaches are applied to parameterize these minor absorption. The parameterizations are accurate and require little extra time for computing radiative fluxes. They have been efficiently implemented in the various atmospheric models at NASA/Goddard Space Flight Center, including cloud ensemble, mesoscale, and climate models.

  9. Low absorptance porcelain-on-aluminum coating

    Science.gov (United States)

    Leggett, H.

    1979-01-01

    Porcelain thermal-control coating for aluminum sheet and foil has solar absorptance of 0.22. Specially formulated coating absorptance is highly stable, changing only 0.03 after 1,000 hours of exposure to simulated sunlight and can be applied by standard commercial methods.

  10. A Low-Cost Quantitative Absorption Spectrophotometer

    Science.gov (United States)

    Albert, Daniel R.; Todt, Michael A.; Davis, H. Floyd

    2012-01-01

    In an effort to make absorption spectrophotometry available to high school chemistry and physics classes, we have designed an inexpensive visible light absorption spectrophotometer. The spectrophotometer was constructed using LEGO blocks, a light emitting diode, optical elements (including a lens), a slide-mounted diffraction grating, and a…

  11. Regularity of the interband light absorption coefficient

    Indian Academy of Sciences (India)

    Light absorption coefficient; density of states; random operators. 1. ... The operators H. ± ω may be unbounded. However, the finite volume operators H ,ω are symmetric finite-dimensional matrices when is a finite set, so their ...... [1] Atoyan M S, Kazaryan E M and Sarkisyan H A, Interband light absorption in parabolic.

  12. Flue gas treatment with membrane gas absorption

    NARCIS (Netherlands)

    Klaassen, R.; Feron, P.H.M.; Jansen, A.E.

    1998-01-01

    Membrane gas absorption is a new, efficient and flexible way to carry out gas-liquid contacting operations with hollow fibre membranes. Advantages of gas absorption membranes over conventional G-L contactors are: -High specific surface area and rapid mass transfer resulting in very compact and low

  13. Terahertz absorption spectrum of triacetone triperoxide (TATP)

    Science.gov (United States)

    Wilkinson, John; Konek, Christopher T.; Moran, Jesse S.; Witko, Ewelina M.; Korter, Timothy M.

    2009-08-01

    We report here, for the first time, the terahertz absorption spectrum of triacetone triperoxide (TATP). The experimental spectra are coupled with solid-state density functional theory, and preliminary assignments are provided to gain physical insight into the experimental spectrum. The calculated absorption coefficients are in excellent agreement with experiment.

  14. Transporters for the Intestinal Absorption of Cholesterol, Vitamin E, and Vitamin K.

    Science.gov (United States)

    Yamanashi, Yoshihide; Takada, Tappei; Kurauchi, Ryoya; Tanaka, Yusuke; Komine, Toko; Suzuki, Hiroshi

    2017-04-03

    Humans cannot synthesize fat-soluble vitamins such as vitamin E and vitamin K. For this reason, they must be obtained from the diet via intestinal absorption. As the deficiency or excess of these vitamins has been reported to cause several types of diseases and disorders in humans, the intestinal absorption of these nutrients must be properly regulated to ensure good health. However, the mechanism of their intestinal absorption remains poorly understood. Recent studies on cholesterol using genome-edited mice, genome-wide association approaches, gene mutation analyses, and the development of cholesterol absorption inhibitors have revealed that several membrane proteins play crucial roles in the intestinal absorption of cholesterol. Surprisingly, detailed analyses of these cholesterol transporters have revealed that they can also transport vitamin E and vitamin K, providing clues to uncover the molecular mechanisms underlying the intestinal absorption of these fat-soluble vitamins. In this review, we focus on the membrane proteins (Niemann-Pick C1 like 1, scavenger receptor class B type I, cluster of differentiation 36, and ATP-binding cassette transporter A1) that are (potentially) involved in the intestinal absorption of cholesterol, vitamin E, and vitamin K and discuss their physiological and pharmacological importance. We also discuss the related uncertainties that need to be explored in future studies.

  15. Suitability of skin integrity tests for dermal absorption studies in vitro.

    Science.gov (United States)

    Guth, Katharina; Schäfer-Korting, Monika; Fabian, Eric; Landsiedel, Robert; van Ravenzwaay, Ben

    2015-02-01

    Skin absorption testing in vitro is a regulatory accepted alternative method (OECD Guideline 428). Different tests can be applied to evaluate the integrity of the skin samples. Here, we compared the pre- or post-run integrity tests (transepidermal electrical resistance, TEER; transepidermal water loss, TEWL; absorption of the reference compounds water, TWF, or methylene blue, BLUE) and additionally focused on co-absorption of a (3)H-labeled internal reference standard (ISTD) as integrity parameter. The results were correlated to absorption profiles of various test compounds. Limit values of 2kΩ, 10 gm(-2)h(-1) and 4.5∗10(-3)cmh(-1) for the standard methods TEER, TEWL and TWF, respectively, allowed distinguishing between impaired and intact human skin samples in general. Single skin samples did, however, not, poorly and even inversely correlate with the test-compound absorption. In contrast, results with ISTD (e.g. (3)H-testosterone) were highly correlated to the absorption of (14)C-labeled test compounds. Importantly, ISTD did not influence analytics or absorption of test compounds. Therefore, ISTD, especially when adjusted to the physico-chemical properties of test compounds, is a promising concept to assess the integrity of skin samples during the whole course of absorption experiments. However, a historical control dataset is yet necessary for a potential routine application. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

  16. Enriching Absorptive Capacity Through Social Interaction

    DEFF Research Database (Denmark)

    Hotho, Jasper Jaap; Becker-Ritterspach, Florian; Saka-Helmhout, Ayse

    absorptive capacity as it enables employees to participate in the transformation of new knowledge to the local context. Second, the findings illustrate how organizational conditions at the subsidiary level can impact subsidiary absorptive capacity by enabling or constraining local interaction patterns......Absorptive capacity is frequently highlighted as a key determinant of knowledge transfer within MNEs. But how individual behaviour translates to absorptive capacity at the subsidiary level, and exactly how this is contingent on subsidiaries’ social context, remains under-addressed. This not only...... limits our understanding of the causal linkage between individual and organizational level absorptive capacity, it also hampers further research on potentially relevant managerial and organizational antecedents, and limits the implications we can draw for practitioners in the field seeking to increase...

  17. Enriching Absorptive Capacity through Social Interaction

    DEFF Research Database (Denmark)

    Hotho, Jasper J.; Saka-Helmhout, Ayse; Becker-Ritterspach, Florian

    2012-01-01

    for subsidiary absorptive capacity as it enables employees to participate in the transformation of new knowledge to the local context and the development of local applications. The findings also illustrate how organizational conditions at the subsidiary level can impact subsidiary absorptive capacity by enabling......Absorptive capacity is frequently highlighted as a key determinant of knowledge transfer within multinational enterprises. But how individual behaviour translates into absorptive capacity at the subsidiary level, and how this is contingent on subsidiaries' social context, remains under......-addressed. This not only limits our understanding of the relationship between individual- and organizational-level absorptive capacity, but also hampers further research on potentially relevant managerial and organizational antecedents, and limits the implications we can draw for practitioners who seek to increase...

  18. Novel absorption detection techniques for capillary electrophoresis

    Energy Technology Data Exchange (ETDEWEB)

    Xue, Yongjun [Iowa State Univ., Ames, IA (United States)

    1994-07-27

    Capillary electrophoresis (CE) has emerged as one of the most versatile separation methods. However, efficient separation is not sufficient unless coupled to adequate detection. The narrow inner diameter (I.D.) of the capillary column raises a big challenge to detection methods. For UV-vis absorption detection, the concentration sensitivity is only at the μM level. Most commercial CE instruments are equipped with incoherent UV-vis lamps. Low-brightness, instability and inefficient coupling of the light source with the capillary limit the further improvement of UV-vis absorption detection in CE. The goals of this research have been to show the utility of laser-based absorption detection. The approaches involve: on-column double-beam laser absorption detection and its application to the detection of small ions and proteins, and absorption detection with the bubble-shaped flow cell.

  19. [Protein absorption in children with giardiasis].

    Science.gov (United States)

    Vega-Franco, L; Alvarez, E L; Romo, G; Bernal, R M

    1982-01-01

    With the object of investigating if Giardiasis interferes in the intestinal absorption of proteins, a study was made testing the absorption of gelatin in eleven. The determination of alpha-aminonitrogen, before giving gelatin, and the increase shown two hours later, was the criterion used to measure the capacity of absorption. Once the estimated basal had been carried out each of the children received tinidazol for three days, after which the large amount of gelatin was given once again so as to estimate any changes in the absorption, one the parasite had been eliminated. The results demonstrate that the presence of giardia in the intestine significantly restricts the absorption of the gelatin. We offer as proof the results of these findings in the growth of children who harbour this parasite.

  20. Calcium Absorption in Infants and Small Children: Methods of Determination and Recent Findings

    Directory of Open Access Journals (Sweden)

    Steven A. Abrams

    2010-04-01

    Full Text Available Determining calcium bioavailability is important in establishing dietary calcium requirements. In infants and small children, previously conducted mass balance studies have largely been replaced by stable isotope-based studies. The ability to assess calcium absorption using a relatively short 24-hour urine collection without the need for multiple blood samples or fecal collections is a major advantage to this technique. The results of these studies have demonstrated relatively small differences in calcium absorption efficiency between human milk and currently available cow milk-based infant formulas. In older children with a calcium intake typical of Western diets, calcium absorption is adequate to meet bone mineral accretion requirements.

  1. FDI ATTRACTION AND INNOVATION POLICY: AN ABSORPTIVE CAPACITY APPROACH

    Directory of Open Access Journals (Sweden)

    Bruno Brandäo Fisher

    2015-12-01

    Full Text Available Foreign Direct Investment represents a strategic issue within countries' industrial policies, provided there is a widespread expectation this particular kind of investment can cause positive shocks on host markets' overall capabilities. Our argument, in consonance with dedicated literature, is that these contributions do not take place without "frictions", and that there is a significant complementarity between FDI's effects and the innovation policy framework (particularly those initiatives that influence the existent level of systemic absorptive capacities. Using panel datasets for developing and developed countries we estimate production functions taking labor productivity, industrial value added, and high-tech exports as output indicators of National Innovation Systems. Through the application of interaction terms we find that levels of absorptive capacity measured by aggregate R&D expenditures determine the effective generation of benefits arising from multinational firms, while human capital conditions seem to play a marginal mediating role in this process.

  2. Absorption-Line Studies of Seyfert Galaxies

    Science.gov (United States)

    Shull, J. Michael

    We propose to undertake a "reverberation analysis" of the variable absorption lines ill two Seyfert Galaxies (NGC 4051 and Mrk 279) to help understand the origin of intrinsic absorption lines in AGNs. Stich an analysis is a powerful tool for elucidating the radial distribution of absorbing gas in the broad-line region (BLR) and narrow-line region (NLR). Only two Seyferts have previously been studied with this technique: NGC 4151 (Bromage el al. 1985; Clavel et al. 1987) and NGC 3516 (Voit, Shull, and Begelman 1987). The absorption features have been interpreted as an outflow of ionized clouds from the nuclear region or from an accretion disk affected by UV/X-ray heating. Neither the source of the absorbing gas in these Seyferts nor the "gene" which distingishes them from other Seyferts is known. Until the 1984 onset of absorption in Mrk 279, broad self-absorbed. lines had been observed only in Seyferts of low intrinsic luminosity, such as NGC 4051. Mrk 279 is intrinsically much brighter, and therefore more quasar-like, than the other three absorptionline Seyfert I's in the CfA sample. Thus, it may show how the absorption phenomenon changes at higher luminosity and could bridge the gap between the low luminosity absorption-line Seyferts and the well-studied broad absorption-line (BAL) QSO's. In addition, Mrk 279's significant redshift will allow us to study, for the first time, the Ly-alpha line in an absorption-line Seyfert. With 3 US-1 shifts for each of these two underobserved Seyferts, we can double the number of objects in which absorption-line variability has been studied and investigate why the absorption-line strengths correlate or anti-correlate with the UV continuum.

  3. Monitoring Telluric Absorption with CAMAL

    Science.gov (United States)

    Baker, Ashley D.; Blake, Cullen H.; Sliski, David H.

    2017-08-01

    Ground-based astronomical observations may be limited by telluric water vapor absorption, which is highly variable in time and significantly complicates both spectroscopy and photometry in the near-infrared (NIR). To achieve the sensitivity required to detect Earth-sized exoplanets in the NIR, simultaneous monitoring of precipitable water vapor (PWV) becomes necessary to mitigate the impact of variable telluric lines on radial velocity measurements and transit light curves. To address this issue, we present the Camera for the Automatic Monitoring of Atmospheric Lines (CAMAL), a stand-alone, inexpensive six-inch aperture telescope dedicated to measuring PWV at the Fred Lawrence Whipple Observatory on Mount Hopkins. CAMAL utilizes three narrowband NIR filters to trace the amount of atmospheric water vapor affecting simultaneous observations with the MINiature Exoplanet Radial Velocity Array (MINERVA) and MINERVA-Red telescopes. Here, we present the current design of CAMAL, discuss our data analysis methods, and show results from 11 nights of PWV measurements taken with CAMAL. For seven nights of data we have independent PWV measurements extracted from high-resolution stellar spectra taken with the Tillinghast Reflector Echelle Spectrometer (TRES) also located on Mount Hopkins. We use the TRES spectra to calibrate the CAMAL absolute PWV scale. Comparisons between CAMAL and TRES PWV estimates show excellent agreement, matching to within 1 mm over a 10 mm range in PWV. Analysis of CAMAL’s photometric precision propagates to PWV measurements precise to better than 0.5 mm in dry (PWV < 4 mm) conditions. We also find that CAMAL-derived PWVs are highly correlated with those from a GPS-based water vapor monitor located approximately 90 km away at Kitt Peak National Observatory, with a root mean square PWV difference of 0.8 mm.

  4. Differentiation-dependent activation of the human intestinal alkaline phosphatase promoter by HNF-4 in intestinal cells

    DEFF Research Database (Denmark)

    Olsen, Line; Bressendorff, Simon; Troelsen, Jesper T

    2005-01-01

    The intestinal alkaline phosphatase gene (ALPI) encodes a digestive brush-border enzyme, which is highly upregulated during small intestinal epithelial cell differentiation. To identify new putative promoter motifs responsible for the regulation of ALPI expression during differentiation...... of the enterocytes, we have conducted a computer-assisted cis-element search of the proximal human ALPI promoter sequence. A putative recognition site for the transcription factor hepatocyte nuclear factor (HNF)-4 was predicted at the positions from -94 to -82 in relation to the translational start site. The ability...

  5. Aerosol Angstrom Absorption Coefficient Comparisons during MILAGRO.

    Science.gov (United States)

    Marley, N. A.; Marchany-Rivera, A.; Kelley, K. L.; Mangu, A.; Gaffney, J. S.

    2007-12-01

    Measurements of aerosol absorption were obtained as part of the MAX-Mex component of the MILAGRO field campaign at site T0 (Instituto Mexicano de Petroleo in Mexico City) by using a 7-channel aethalometer (Thermo- Anderson) during the month of March, 2006. The absorption measurements obtained in the field at 370, 470, 520, 590, 660, 880, and 950 nm were used to determine the aerosol Angstrom absorption exponents by linear regression. Since, unlike other absorbing aerosol species (e.g. humic like substances, nitrated PAHs), black carbon absorption is relatively constant from the ultraviolet to the infrared with an Angstrom absorption exponent of -1 (1), a comparison of the Angstrom exponents can indicate the presence of aerosol components with an enhanced UV absorption over that expected from BC content alone. The Angstrom exponents determined from the aerosol absorption measurements obtained in the field varied from - 0.7 to - 1.3 during the study and was generally lower in the afternoon than the morning hours, indicating an increase in secondary aerosol formation and photochemically generated UV absorbing species in the afternoon. Twelve-hour integrated samples of fine atmospheric aerosols (Petroleo (IMP) and CENICA.

  6. Gas treating absorption theory and practice

    CERN Document Server

    Eimer, Dag

    2014-01-01

    Gas Treating: Absorption Theory and Practice provides an introduction to the treatment of natural gas, synthesis gas and flue gas, addressing why it is necessary and the challenges involved.  The book concentrates in particular on the absorption-desorption process and mass transfer coupled with chemical reaction. Following a general introduction to gas treatment, the chemistry of CO2, H2S and amine systems is described, and selected topics from physical chemistry with relevance to gas treating are presented. Thereafter the absorption process is discussed in detail, column hardware is explain

  7. Psychological absorption. Affect investment in marijuana intoxication.

    Science.gov (United States)

    Fabian, W D; Fishkin, S M

    1991-01-01

    Absorption (a trait capacity for total attentional involvement) was reported to increase during episodes of marijuana intoxication. Several subsets of the absorption scale items specifically characterized marijuana intoxication, and groups of users and nonusers showed differential affective involvement with these experiences. Additionally, within the drug-using group, a positive correlation between frequency of marijuana use and affective ratings of these experiences was found. The findings support the hypothesis that a specific type of alteration in consciousness that enhances capacity for total attentional involvement (absorption) characterizes marijuana intoxication, and that this enhancement may act as a reinforcer, possibly influencing future use.

  8. Coherent Absorption of N00N States.

    Science.gov (United States)

    Roger, Thomas; Restuccia, Sara; Lyons, Ashley; Giovannini, Daniel; Romero, Jacquiline; Jeffers, John; Padgett, Miles; Faccio, Daniele

    2016-07-08

    Recent results in deeply subwavelength thickness films demonstrate coherent control and logical gate operations with both classical and single-photon light sources. However, quantum processing and devices typically involve more than one photon and nontrivial input quantum states. Here we experimentally investigate two-photon N00N state coherent absorption in a multilayer graphene film. Depending on the N00N state input phase, it is possible to selectively choose between single- or two-photon absorption of the input state in the graphene film. These results demonstrate that coherent absorption in the quantum regime exhibits unique features, opening up applications in multiphoton spectroscopy and imaging.

  9. Connecting X-ray absorption and 21 cm neutral hydrogen absorption in obscured radio AGN

    Science.gov (United States)

    Moss, V. A.; Allison, J. R.; Sadler, E. M.; Urquhart, R.; Soria, R.; Callingham, J. R.; Curran, S. J.; Musaeva, A.; Mahony, E. K.; Glowacki, M.; Farrell, S. A.; Bannister, K. W.; Chippendale, A. P.; Edwards, P. G.; Harvey-Smith, L.; Heywood, I.; Hotan, A. W.; Indermuehle, B. T.; Lenc, E.; Marvil, J.; McConnell, D.; Reynolds, J. E.; Voronkov, M. A.; Wark, R. M.; Whiting, M. T.

    2017-11-01

    Many radio galaxies show the presence of dense and dusty gas near the active nucleus. This can be traced by both 21 cm H I absorption and soft X-ray absorption, offering new insight into the physical nature of the circumnuclear medium of these distant galaxies. To better understand this relationship, we investigate soft X-ray absorption as an indicator for the detection of associated H I absorption, as part of preparation for the First Large Absorption Survey in H I to be undertaken with the Australian Square Kilometre Array Pathfinder (ASKAP). We present the results of our pilot study using the Boolardy Engineering Test Array, a precursor to ASKAP, to search for new absorption detections in radio sources brighter than 1 Jy that also feature soft X-ray absorption. Based on this pilot survey, we detected H I absorption towards the radio source PKS 1657-298 at a redshift of z = 0.42. This source also features the highest X-ray absorption ratio of our pilot sample by a factor of 3, which is consistent with our general findings that X-ray absorption predicates the presence of dense neutral gas. By comparing the X-ray properties of active galactic nuclei with and without detection of H I absorption at radio wavelengths, we find that X-ray hardness ratio and H I absorption optical depth are correlated at a statistical significance of 4.71σ. We conclude by considering the impact of these findings on future radio and X-ray absorption studies.

  10. The absorption, distribution and excretion of 1- and 2-.

    Science.gov (United States)

    Sanders, D J; Howes, D; Earl, L K

    2001-07-01

    Human breast milk is rich in 2-palmitoyl 1,3 unsaturated triacyglycerols and during the neonatal period, when milk is the sole source of nutrients, their role could be particularly important. Betapol is a novel triacylglycerol mix resembling human breast milk in its high palmitic acid content and positional distribution. The total fat absorption from Betapol has been shown to be higher than fat from conventional infant milk formulas and closer to human breast milk in infants. However, the relative fate of purified palmitic acid esterified to glycerol in the 1-, 3- and 2-positions in neonatal and young animals has not previously been established. Therefore, the fate of orally administered 1-[1-14C]palmitoyl, 2,3 dioleoyl glycerol ([14C]POO) and 1,3 dioleoyl,2-[1-14C]palmitoyl glycerol (O[14C]PO) was investigated in suckling and weanling rats using liquid scintillation counting of tissues and expired air and whole-body autoradiography. The results obtained indicate that orally administered [14C]POO and O[14C]PO are extensively absorbed from the gut, probably either as palmitic acid or as a palmitoyl glyceride in both suckling and weanling rats. Radioactivity initially concentrated in brown fat with apparent migration to the white fat of weanling rats by 96 h. Levels of 14C were low in blood, brain and other tissues. Excretion of 14C was mainly by expiration of CO(2) (approximately 72% in 96 h), indicating beta-oxidation as a major route of metabolism. Urine and faeces accounted for only approximately 6% of the excreted radioactivity. The design and size of the experiment did not allow tests of statistical significance between the absorption and excretion of OPO and POO to be conducted. However, the absorption, distribution, beta-oxidation and excretion appeared to be similar.

  11. Gintonin absorption in intestinal model systems

    Directory of Open Access Journals (Sweden)

    Byung-Hwan Lee

    2018-01-01

    Conclusion: The present study shows that gintonin could be absorbed in the intestine through transcellular and paracellular diffusion, and active transport. In addition, the lipid component of gintonin might play a key role in its intestinal absorption.

  12. Multiphoton absorption in amyloid protein fibres

    Science.gov (United States)

    Hanczyc, Piotr; Samoc, Marek; Norden, Bengt

    2013-12-01

    Fibrillization of peptides leads to the formation of amyloid fibres, which, when in large aggregates, are responsible for diseases such as Alzheimer's and Parkinson's. Here, we show that amyloids have strong nonlinear optical absorption, which is not present in native non-fibrillized protein. Z-scan and pump-probe experiments indicate that insulin and lysozyme β-amyloids, as well as α-synuclein fibres, exhibit either two-photon, three-photon or higher multiphoton absorption processes, depending on the wavelength of light. We propose that the enhanced multiphoton absorption is due to a cooperative mechanism involving through-space dipolar coupling between excited states of aromatic amino acids densely packed in the fibrous structures. This finding will provide the opportunity to develop nonlinear optical techniques to detect and study amyloid structures and also suggests that new protein-based materials with sizable multiphoton absorption could be designed for specific applications in nanotechnology, photonics and optoelectronics.

  13. The Driving Forces of Subsidiary Absorptive Capacity

    DEFF Research Database (Denmark)

    Schleimer, Stephanie C.; Pedersen, Torben

    2013-01-01

    capacity in order to compete in its focal market. The dual embeddedness of MNC subsidiaries plays a key role in this investigation, as subsidiaries belong to the MNC network and are simultaneously embedded in their host country environment. We argue that subsidiary absorptive capacity is formed...... as a purposeful response to this dual embeddedness. An analysis of marketing strategy absorptions undertaken by 213 subsidiaries reveals that MNCs can assist their subsidiaries to compete in competitive and dynamic focal markets by forming specific organizational mechanisms that are conducive to the development......The study investigates how a multinational corporation (MNC) can promote the absorptive capacity of its subsidiaries. The focus is on what drives the MNC subsidiary's ability to absorb marketing strategies that are initiated by the MNC parent, as well as how the subsidiary enacts on this absorptive...

  14. Differential Photoacoustic Particle Absorption Monitor Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to develop a highly sensitive and compact monitor to measure light absorption from particulate matters. The fundamental of the proposed device is based on...

  15. Absorption fluids data survey: 1989 update

    Energy Technology Data Exchange (ETDEWEB)

    Macriss, R.A.; Zawacki, T.S. (Institute of Gas Technology, Chicago, IL (USA))

    1989-01-01

    This is an update of a series of prior reports on absorption fluids and data, ORNL/Sub/84-47989/1, 2, 3. It covers additional data developed and published mainly during 1985--88, and cites 44 additional references. Seventy-four different worldwide publications containing data relating to properties of binary, ternary, and multicomponent absorption fluids were identified. Of these, 30 manuscripts include applications of absorption fluid properties data toward evaluation, assessment, or design of chillers or heat pumps but do not include actual fluid properties data. The remaining 44 publications date as far back as 1929, but over 50% of these documents were published between 1985 and 1988. The texts of the 44 manuscripts are in English, German, Japanese, Russian, or French. The absorption fluids discussed in the 44 documents are combinations of 9 different refrigerant'' compounds and 30 single, 7 binary, and 1 ternary absorbent'' compounds. 44 refs., 21 tabs.

  16. Extending Organizational Antecedents Of Absorptive Capacity

    DEFF Research Database (Denmark)

    Burcharth, Ana Luiza de Araújo; Lettl, Christopher; Ulhøi, John Parm

    2015-01-01

    on organizational characteristics that encourage experimentation. Specifically, we argue that characteristics such as slack resources, tolerance for failure, willingness to cannibalize and external openness are important organizational antecedents for knowledge absorption activities as they prevent inertia. Drawing...

  17. Pathlength Determination for Gas in Scattering Media Absorption Spectroscopy

    Science.gov (United States)

    Mei, Liang; Somesfalean, Gabriel; Svanberg, Sune

    2014-01-01

    Gas in scattering media absorption spectroscopy (GASMAS) has been extensively studied and applied during recent years in, e.g., food packaging, human sinus monitoring, gas diffusion studies, and pharmaceutical tablet characterization. The focus has been on the evaluation of the gas absorption pathlength in porous media, which a priori is unknown due to heavy light scattering. In this paper, three different approaches are summarized. One possibility is to simultaneously monitor another gas with known concentration (e.g., water vapor), the pathlength of which can then be obtained and used for the target gas (e.g., oxygen) to retrieve its concentration. The second approach is to measure the mean optical pathlength or physical pathlength with other methods, including time-of-flight spectroscopy, frequency-modulated light scattering interferometry and the frequency domain photon migration method. By utilizing these methods, an average concentration can be obtained and the porosities of the material are studied. The last method retrieves the gas concentration without knowing its pathlength by analyzing the gas absorption line shape, which depends upon the concentration of buffer gases due to intermolecular collisions. The pathlength enhancement effect due to multiple scattering enables also the use of porous media as multipass gas cells for trace gas monitoring. All these efforts open up a multitude of different applications for the GASMAS technique. PMID:24573311

  18. Pathlength Determination for Gas in Scattering Media Absorption Spectroscopy

    Directory of Open Access Journals (Sweden)

    Liang Mei

    2014-02-01

    Full Text Available Gas in scattering media absorption spectroscopy (GASMAS has been extensively studied and applied during recent years in, e.g., food packaging, human sinus monitoring, gas diffusion studies, and pharmaceutical tablet characterization. The focus has been on the evaluation of the gas absorption pathlength in porous media, which a priori is unknown due to heavy light scattering. In this paper, three different approaches are summarized. One possibility is to simultaneously monitor another gas with known concentration (e.g., water vapor, the pathlength of which can then be obtained and used for the target gas (e.g., oxygen to retrieve its concentration. The second approach is to measure the mean optical pathlength or physical pathlength with other methods, including time-of-flight spectroscopy, frequency-modulated light scattering interferometry and the frequency domain photon migration method. By utilizing these methods, an average concentration can be obtained and the porosities of the material are studied. The last method retrieves the gas concentration without knowing its pathlength by analyzing the gas absorption line shape, which depends upon the concentration of buffer gases due to intermolecular collisions. The pathlength enhancement effect due to multiple scattering enables also the use of porous media as multipass gas cells for trace gas monitoring. All these efforts open up a multitude of different applications for the GASMAS technique.

  19. Lectin-binding sites in the epithelium of normal human appendix vermiformis and in acute appendicitis.

    Science.gov (United States)

    Brinck, U; Bosbach, R; Korabiowska, M; Schauer, A; Gabius, H J

    1995-01-01

    By using histochemical methods, the binding pattern of various lectins in the epithelium of normal human appendix vermiformis was assessed. In addition to plant and invertebrate sugar receptors with nominal monosaccharide specificity for alpha-L-Fuc (UEA-I), alpha-D-Man and alpha-D-Gluc (Con A), alpha-D-GalNAc (DBA), D-GalNAc (SBA, HPA) beta-D-Gal (RCA-I) and D-Gal (VAA), a mammalian beta-galactoside-specific lectin (MW, 14 kDa) was included in the applied panel. The apical surface of enterocytes presented binding sites for RCA-I on all cells, binding sites of UEA-I, DBA, SBA, HPA and VAA heterogeneously and no binding sites of Con A and 14 kDa. Binding sites of DBA, SBA, HPA, VAA and RCA-I within enterocytes were located primarily focally in a supranuclear position, whereas Con A and 14 kDa bound to the cytoplasm both in apical and basal cell parts. In the follicle-associated epithelium more enterocytes expressed SBA- and VAA-binding sites than in the crypt epithelium. No differences between the lectin-binding pattern of M-cells and enterocytes were found in the follicle-associated epithelium. Intraepithelial macrophages were heterogeneously positive for the full panel of applied lectins. In contrast, intraepithelial lymphatic cells expressed binding sites only for RCA-I and less prominently for Con A, VAA and 14 kDa. Goblet cell mucus contained lectin-binding sites in a heterogeneous manner: binding sites for Con A were not detected in goblet cells for DBA, SBA, VAA and 14 kDa in less than 20%, for UEA-I in 20-40%, for HPA in 40-60% and for RCA-I in 60-100% of the goblet cells. Secreted mucus differed in its lectin-binding capacity from intracellular goblet cell mucus selectively by an increase of UEA-I, SBA- and RCA-I-binding sites and a lack of 14 kDa-binding sites. Comparative study of lectin binding to goblet cell mucin in another region of the large intestine, namely the rectosigmoid, demonstrated that DBA, SBA and 14 kDa bound mainly to the distal colon

  20. Ultraviolet absorption cross sections of hydrogen peroxide

    Science.gov (United States)

    Lin, C. L.; Rohatgi, N. K.; Demore, W. B.

    1978-01-01

    Absorption cross-sections of hydrogen peroxide vapor and of neutral aqueous solutions of hydrogen peroxide were measured in the wavelength range from 195 to 350 nm at 296 K. The spectrophotometric procedure is described, and the reported cross-sections are compared with values obtained by other researchers. Photodissociation coefficients of atmospheric H2O2 were calculated for direct absorption of unscattered solar radiation, and the vertical distributions of these coefficients are shown for various solar zenith angles.

  1. Water Absorption Behavior of Hemp Hurds Composites

    OpenAIRE

    Nadezda Stevulova; Julia Cigasova; Pavol Purcz; Ivana Schwarzova; Frantisek Kacik; Anton Geffert

    2015-01-01

    In this paper, water sorption behavior of 28 days hardened composites based on hemp hurds and inorganic binder was studied. Two kinds of absorption tests on dried cube specimens in deionized water bath at laboratory temperature were performed. Short-term (after one hour water immersion) and long-term (up to 180 days) water absorption tests were carried out to study their durability. Short-term water sorption behavior of original hemp hurds composites depends on mean particle length of hemp an...

  2. Systemic Absorption of Nanomaterials by Oral Exposure

    DEFF Research Database (Denmark)

    Binderup, Mona-Lise; Bredsdorff, Lea; Beltoft, Vibe Meister

    This report and accompanying database systematically evaluates the reliability and relevance of the existing scientific literature regarding systemic absorption of nanomaterials by oral exposure and makes specific recommendations for future testing approaches.......This report and accompanying database systematically evaluates the reliability and relevance of the existing scientific literature regarding systemic absorption of nanomaterials by oral exposure and makes specific recommendations for future testing approaches....

  3. Enhancement of Kerr nonlinearity completely without absorption

    Science.gov (United States)

    Liang, Hong; Niu, Yueping; Deng, Li; Gong, Shangqing

    2017-12-01

    We investigate the enhancement of the Kerr nonlinearity in a four-level tripod-type atomic system completely without absorption. We study the effect of the incoherent pumping on the nonlinear susceptibility of the probe field and show that compared with that without the incoherent pumping, the Kerr nonlinearity can be enhanced with completely suppressed absorption at two different probe frequencies. Thus, we can get a symmetrical enhanced Kerr nonlinearity. Particularly, all of our results are in the case of Doppler broadening.

  4. The Automation of Sound Absorption Coefficient Measurement

    OpenAIRE

    Hermawanto, Denny; Suwandi, Achmad

    2006-01-01

    By manual method, the sound absorption coefficient measurement should be done by utilizing many type of equipment such as: measuring amplifier, level recorder, band-pass filter, protactor, etc. However it caused inefficient and need longer time in processing measurement data, therefore the automation system of sound absorption coefficient has been realized. An acoustical real time analyzer type B&K 2144 has been used to record the decay of sound pressure level, thus the processing data is dri...

  5. Morphology of Southern Hemisphere Riometer Auroral Absorption

    Science.gov (United States)

    2006-06-01

    Departamento de Geofísica Universidad de Concepción, Concepción CHILE foppiano@udec.cl ABSTRACT A morphology of riometer auroral absorption is...PROJECT NUMBER 5e. TASK NUMBER 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) Departamento de Geofísica Universidad de...UNCLASSIFIED/UNLIMITED UNCLASSIFIED/UNLIMITED MORPHOLOGY OF SOUTHERN HEMISPHERE RIOMETER AURORAL ABSORPTION Alberto J. Foppiano Departamento de

  6. Simulation of an absorption cooling system

    Energy Technology Data Exchange (ETDEWEB)

    Egrican, N. (Istanbul Technical Univ. (TR). Dept. of Mechanical Engineering); Yigit, A. (Uludag Univ., Bursa (TR). Faculty of Engineering)

    1992-06-01

    We describe a finite difference solution for combined heat and mass transfer on vapor absorption into a laminar liquid film. Heat- and mass-transfer coefficients are determined by calculating temperature and concentration variations at the film. A modular computer program has been developed for absorption systems to simulate various cycle configurations. The influence of component temperatures and heat-exchanger effectiveness on cooling coefficients of performance and component heat-transfer rates has been investigated to define optimum operating conditions. (author).

  7. Variations in the spectral values of specific absorption of phytoplankton

    Digital Repository Service at National Institute of Oceanography (India)

    Sathyendranath, S.; Lazzara, L.; Prieur, L.

    Absorption spectra of laboratory cultures of eight species of phytoplankton were studied. These spectra, normalized per unit of chlorophyll a concentration (specific absorption) show variability in magnitude and spectral form. Specific absorption...

  8. Antibodies to enterocyte epitopes in celiac disease

    Czech Academy of Sciences Publication Activity Database

    Tučková, Ludmila; Karská, Kamila; Farré, Maria; Rossmann, Pavel; Steiner, L.; Tlaskalová, Helena

    1995-01-01

    Roč. 76, č. 1 (1995), s. 75 ISSN 0090-1229. [International congress of mucosal immunology /8./. San Diego, 17.07.1995-20.07.1995] R&D Projects: GA ČR GA310/93/1093; GA AV ČR IAA720401 Impact factor: 2.088, year: 1995

  9. Ferritin Assembly in Enterocytes of Drosophila melanogaster

    Directory of Open Access Journals (Sweden)

    Abraham Rosas-Arellano

    2016-02-01

    Full Text Available Ferritins are protein nanocages that accumulate inside their cavity thousands of oxidized iron atoms bound to oxygen and phosphates. Both characteristic types of eukaryotic ferritin subunits are present in secreted ferritins from insects, but here dimers between Ferritin 1 Heavy Chain Homolog (Fer1HCH and Ferritin 2 Light Chain Homolog (Fer2LCH are further stabilized by disulfide-bridge in the 24-subunit complex. We addressed ferritin assembly and iron loading in vivo using novel transgenic strains of Drosophila melanogaster. We concentrated on the intestine, where the ferritin induction process can be controlled experimentally by dietary iron manipulation. We showed that the expression pattern of Fer2LCH-Gal4 lines recapitulated iron-dependent endogenous expression of the ferritin subunits and used these lines to drive expression from UAS-mCherry-Fer2LCH transgenes. We found that the Gal4-mediated induction of mCherry-Fer2LCH subunits was too slow to effectively introduce them into newly formed ferritin complexes. Endogenous Fer2LCH and Fer1HCH assembled and stored excess dietary iron, instead. In contrast, when flies were genetically manipulated to co-express Fer2LCH and mCherry-Fer2LCH simultaneously, both subunits were incorporated with Fer1HCH in iron-loaded ferritin complexes. Our study provides fresh evidence that, in insects, ferritin assembly and iron loading in vivo are tightly regulated.

  10. Dimeric assembly of enterocyte brush border enzymes

    DEFF Research Database (Denmark)

    Danielsen, E M

    1994-01-01

    The noncovalent, dimeric assembly of small intestinal brush border enzymes was studied by sedimentation analysis in density gradients of extracts of pulse-labeled pig jejunal mucosal explants. Like aminopeptidase N (EC 3.4.11.2), sucrase-isomaltase (EC 3.2.1.48-10), aminopeptidase A (EC 3...... appearance of the liposome-reconstituted enzyme [Norén et al. (1986) J. Biol. Chem. 261, 12306-12309], showing only the inner, membrane-anchored domains of the monomers to be in close contact with one another while the outer domains are far apart. In contrast to the other brush border enzymes studied...

  11. Small intestinal absorption during endotoxemia in swine.

    Science.gov (United States)

    Kanno, S; Emil, S; Kosi, M; Monforte-Munoz, H; Atkinson, J

    1996-10-01

    We studied the effects of systemic endotoxemia on small intestinal absorption in an in vivo animal model. Seven adolescent Yorkshire swine underwent creation of 25 cm distal ileal Thiry-Vella fistulae. After 1 week recovery, the fistulae were perfused with a solution of glucose and electrolytes labeled with 14C-PEG, and net absorption of water, Na+, Cl-, and glucose was calculated. Animals were studied under three different conditions: (1) Basal fasting state, (2) immediately after intravenous injection of E. coli lipopolysaccharide (LPS; 250 micrograms/kg), and (3) 24 hours after LPS. Water, Na+, and Cl- absorption was significantly reduced 2 hours after LPS, but recovered to baseline values by the third hour after LPS. Twenty-four hours after LPS water, Na+, and Cl- absorption was significantly decreased below baseline values. Glucose absorption after LPS paralleled that of water and electrolytes, except that the transient early recovery was not observed. Histological studies of the ileum after LPS showed marked epithelial inflammation at 6 hours, villous atrophy at 24 hours, and signs of recovery at 7 days. Intestinal absorption of water, electrolytes, and glucose is adversely affected in the immediate and early periods after an endotoxemic episode, but the histological epithelial injury secondary to endotoxemia is reversible.

  12. Antioxidant content and ultraviolet absorption characteristics of human tears.

    Science.gov (United States)

    Choy, Camus Kar Man; Cho, Pauline; Benzie, Iris F F

    2011-04-01

    Dry eye syndrome is a common age-related disorder, and decreased antioxidant/ultraviolet (UV) radiation protection in tears may be part of the cause. This study aimed to compare the tear antioxidant content and flow rate in young and older adults. The total antioxidant content and UV absorbing properties of various commercially available ophthalmic solutions used to alleviate dry eye symptoms were also examined. Minimally stimulated tears were collected from 120 healthy Chinese adults with no ocular pathology. Two age groups were studied: 19 to 29 years (n = 58) and 50 to 75 years (n = 62). Tear samples from each subject and 13 ophthalmic solutions were analyzed for total antioxidant content (as the Ferric Reducing/Antioxidant Power value). Tear flow rates were estimated from time taken to collect a fixed volume of tear fluid. UV absorbance spectra of pooled fresh reflex tear fluid and the ophthalmic solutions were determined. Results showed that the antioxidant content of minimally stimulated tears from older subjects (398 ± 160 μmol/l) was not significantly lower than that of younger subjects (348 ± 159 μmol/l; p = 0.0915). However, there was a significant difference in the tear flow rates between the two groups (p tears. The effect of low flow rate on the dynamic antioxidant supply to the corneal surface indicates that older subjects have poorer overall defense against photooxidative and other oxidative processes. This could predispose older persons to corneal stress and development of dry eye syndrome. The commercially available artificial tears tested lack both the antioxidant content and UV absorbing characteristics of natural tears. Artificial tears formulations that help restore natural antioxidant and UV absorbing properties to the tear film of the aging eye may help prevent or improve dry eye symptoms and promote ocular health.

  13. Methodologies to study human intestinal absorption. A review

    NARCIS (Netherlands)

    Versantvoort CHM; Rompelberg CJM; Sips AJAM; LBM

    2000-01-01

    Concepts in risk assessment practice are expressed in terms of external exposure, while internal exposure determines whether toxic effects will occur. Often only a fraction of the ingested compound is absorbed external exposure, resulting in a lower internal exposure. The methodologies most commonly

  14. In vitro System for Assessing Dioxin Absorption by Intestinal Epithelial Cells and for Preventing this Absorption by Food Substances.

    Science.gov (United States)

    Natsume, Yayoi; Satsu, Hideo; Hamada, Mika; Kitamura, Kazushige; Okamoto, Naoto; Shimizu, Makoto

    2005-01-01

    A system for assessing intestinal dioxin absorption was established by applying a Caco-2 cell monolayer and stable dioxin-responsive cell line. The stable dioxin-responsive cell line was established by introducing a plasmid incorporating the human CYP1A1 promoter into human hepatic HepG2 genomic DNA upstream of the luciferase gene. 2,3,7,8-Tetrachlorodibenzodioxin (TCDD) was added to the apical side of differentiated human intestinal epithelial Caco-2 cell monolayers that had been cultured on a semipermeable membrane. The basal medium was taken after an appropriate incubation time and added to the dioxin-responsive cells, the TCDD content then being analyzed by a luciferase assay. The amount of TCDD in the basal medium increased in a dose- and time-dependent manner, the results being sufficiently sensitive and reproducible. The inhibition of TCDD permeability to the Caco-2 cell monolayer by such food substances as chlorophyll, insoluble corn fiber and tea dregs were observed by this in vitro assessment system. The system will therefore be useful to identify food substances having a preventive effect on the intestinal absorption of dioxins.

  15. Hyperpolarized 13C pyruvate mouse brain metabolism with absorptive-mode EPSI at 1 T

    Science.gov (United States)

    Miloushev, Vesselin Z.; Di Gialleonardo, Valentina; Salamanca-Cardona, Lucia; Correa, Fabian; Granlund, Kristin L.; Keshari, Kayvan R.

    2017-02-01

    The expected signal in echo-planar spectroscopic imaging experiments was explicitly modeled jointly in spatial and spectral dimensions. Using this as a basis, absorptive-mode type detection can be achieved by appropriate choice of spectral delays and post-processing techniques. We discuss the effects of gradient imperfections and demonstrate the implementation of this sequence at low field (1.05 T), with application to hyperpolarized [1-13C] pyruvate imaging of the mouse brain. The sequence achieves sufficient signal-to-noise to monitor the conversion of hyperpolarized [1-13C] pyruvate to lactate in the mouse brain. Hyperpolarized pyruvate imaging of mouse brain metabolism using an absorptive-mode EPSI sequence can be applied to more sophisticated murine disease and treatment models. The simple modifications presented in this work, which permit absorptive-mode detection, are directly translatable to human clinical imaging and generate improved absorptive-mode spectra without the need for refocusing pulses.

  16. Analyzing lead absorption by the sycamore tree species in the industrial park of Rasht, Iran.

    Science.gov (United States)

    Hashemi, Seyed Armin; FallahChay, Mir Mozaffar; Tarighi, Fattaneh

    2015-07-01

    In this study, the subject of heavy metal concentration in soil, rock, sediment, surface water and groundwater, which can be caused by natural or man-posed pollution, was analyzed in the industrial park of Rasht. These concentrations were compared with the standard range of environmental data. Heavy metals are important environmental pollutants that can cause health hazards to humans, plants and microorganisms by entering food chain. This study aimed to investigate the absorption of lead by the leaves of sycamore tree species in the industrial park of Rasht. For this purpose, a sample of 32 sycamore tree species were randomly selected at a specified time, and the concentration of lead were measured using an atomic absorption device. Results showed that the amount of lead absorption by sycamore leaves is remarkable. The highest amount of lead absorption by sycamore leaves was detected at station 1 (Khazar Steel) and the lowest amount at station 2 (control station). © The Author(s) 2012.

  17. Arachidonic acid intestinal absorption: mechanism of transport and influence of luminal factors of absorption in vitro.

    Science.gov (United States)

    Chow, S L; Hollander, D

    1978-11-01

    The mechanism and characteristics of intestinal absorption of arachidonic acid were studied in vitro using everted intestinal sacs of the rat. Arachidonic acid absorption was studied at concentrations of 5 micron to 8.36 mM. The plot of absorption rate vs. concentration fitted best to a rectangular hyperbola at low micron concentrations and to a straight linear relationship in the mM range of concentrations. Metabolic inhibitors and uncouplers did not change absorption in either range of concentrations. The absorption of arachidonic acid increased with thinning of the unstirred water-layer, decrease in the pH, or the substitution of sodium taurocholate by Pluronic F 68 OR Tween 80. Absorption decreased following the equimolar additions of oleic, linoleic, and linolenic acids. Absorption rate did not change when the taurocholate concentration was varied from 5-15 mM or following the additions of butyric or glutamic acids, leucine, lysine, or dextrose. It was concluded that arachidonic acid is absorbed by a concentration-dependent dual mechanism of transport which is not energy dependent. At the low micron range of concentrations, facilitated diffusion is predominant, while at mM concentrations, simple diffusion is the dominant mechanism of absorption. Changes in the intestinal fluid composition, flow rate, and pH can modify the rate of absorption of arachidonic acid.

  18. Digestion and absorption of olive oil

    Directory of Open Access Journals (Sweden)

    Muriana, Francisco J.G.

    2004-03-01

    Full Text Available Olive oil is a monounsaturated (oleic acid-rich fat, mainly constituted by triglycerides (>98 % and minor compounds. As other macronutrients, dietary triglyceride digestion and absorption are a complex processes involving enzyme activities and physicochemical changes. In humans, hydrolysis of olive oil triglycerides begins in the stomach where it is catalyzed by an acid-stable gastric lipase. Triglyceride hydrolysis continues in the duodenum, by the synergetic actions of gastric and colipase-dependent pancreatic lipases and bile secretion. Gastric lipolysis leads to the hydrolysis of 10-30 % of ingested triglycerides, generating mainly diglycerides (DG and free fatty acids. This facilitates subsequent triglyceride hydrolysis by pancreatic lipase by allowing fat emulsification. Pancreatic lipase cleaves the sn-1 and sn-3 positions of triglycerides and/or DG obtaining sn-2 monoglycerides. Different lipid metabolites are quickly absorbed along the epithelial cells of the small intestine, acting olive oil as a supplier of oleic-acid-rich hydrocarbon skeletons for cellular synthesis of triglycerides and phospholipids. Absorption of mostly minor compounds of (extra virgin olive oil takes place in the small intestine, as native or derivatives. Compared to diets rich in polyunsaturated fatty acids, olive oil suppresses gastric acid secretion and is a potent releasing factor of cholecystokinin peptide, which consistently indicate that the consumption of olive oil might be beneficial in digestive diseases.El aceite de oliva es una grasa monoinsaturada (rica en ácido oleico, compuesta por triglicéridos (>98% y componentes menores. En los procesos de digestión y absorción de los triglicéridos participan enzimas y se producen cambios fisicoquímicos. La lipasa gástrica es el componente mayoritario de la actividad lipolítica gástrica en humanos. La hidrólisis de los triglicéridos continúa en el duodeno, por la acción sinérgica de las lipasas g

  19. UV laser long-path absorption spectroscopy

    Science.gov (United States)

    Dorn, Hans-Peter; Brauers, Theo; Neuroth, Rudolf

    1994-01-01

    Long path Differential Optical Absorption Spectroscopy (DOAS) using a picosecond UV laser as a light source was developed in our institute. Tropospheric OH radicals are measured by their rotational absorption lines around 308 nm. The spectra are obtained using a high resolution spectrograph. The detection system has been improved over the formerly used optomechanical scanning device by application of a photodiode array which increased the observed spectral range by a factor of 6 and which utilizes the light much more effectively leading to a considerable reduction of the measurement time. This technique provides direct measurements of OH because the signal is given by the product of the absorption coefficient and the OH concentration along the light path according to Lambert-Beers law. No calibration is needed. Since the integrated absorption coefficient is well known the accuracy of the measurement essentially depends on the extent to which the OH absorption pattern can be detected in the spectra. No interference by self generated OH radicals in the detection lightpath has been observed. The large bandwidth (greater than 0.15 nm) and the high spectral resolution (1.5 pm) allows absolute determination of interferences by other trace gas absorptions. The measurement error is directly accessible from the absorption-signal to baseline-noise ratio in the spectra. The applicability of the method strongly depends on visibility. Elevated concentrations of aerosols lead to considerable attenuation of the laser light which reduces the S/N-ratio. In the moderately polluted air of Julich, where we performed a number of OH measurement spectra. In addition absorption features of unidentified species were frequently detected. A quantitative deconvolution even of the known species is not easy to achieve and can leave residual structures in the spectra. Thus interferences usually increase the noise and deteriorate the OH detection sensitivity. Using diode arrays for sensitive

  20. Identifying the perfect absorption of metamaterial absorbers

    Science.gov (United States)

    Duan, G.; Schalch, J.; Zhao, X.; Zhang, J.; Averitt, R. D.; Zhang, X.

    2018-01-01

    We present a detailed analysis of the conditions that result in unity absorption in metamaterial absorbers to guide the design and optimization of this important class of functional electromagnetic composites. Multilayer absorbers consisting of a metamaterial layer, dielectric spacer, and ground plane are specifically considered. Using interference theory, the dielectric spacer thickness and resonant frequency for unity absorption can be numerically determined from the functional dependence of the relative phase shift of the total reflection. Further, using transmission line theory in combination with interference theory we obtain analytical expressions for the unity absorption resonance frequency and corresponding spacer layer thickness in terms of the bare resonant frequency of the metamaterial layer and metallic and dielectric losses within the absorber structure. These simple expressions reveal a redshift of the unity absorption frequency with increasing loss that, in turn, necessitates an increase in the thickness of the dielectric spacer. The results of our analysis are experimentally confirmed by performing reflection-based terahertz time-domain spectroscopy on fabricated absorber structures covering a range of dielectric spacer thicknesses with careful control of the loss accomplished through water absorption in a semiporous polyimide dielectric spacer. Our findings can be widely applied to guide the design and optimization of the metamaterial absorbers and sensors.

  1. Tissue ultrasound absorption measurement with MRI calorimetry.

    Science.gov (United States)

    Wang, Y; Hunt, J W; Foster, F S; Plewes, D B

    1999-01-01

    The renewed interest in the use of high intensity focused ultrasound (US) for minimally invasive magnetic resonance imaging (MRI)-guided thermal therapy has stimulated a review of the interaction mechanisms of US with tissue. Although the study of tissue US properties has been conducted extensively, agreements on the measured values of tissue US absorption are poor. We propose a noninvasive approach to measure tissue US absorption based on a form of MRI calorimetry. US absorption is measured in a small tissue sample through a knowledge of the US intensity distribution incident on the tissue and an MRI measurement of total absorbed energy arising from US exposure. US absorption measurements were conducted at room temperature for ex-vivo bovine liver tissue at 1 MHz, which led to a measured US absorption coefficient of 0.058 Np/cm or 0.504 dB/cm. Because this approach is noninvasive, the experimental complications exhibited in earlier studies are not present. Furthermore, this approach can be applied over a range of frequencies, tissues, and temperatures, which will aid in understanding of biothermal effects of high intensity US to improve thermal therapy.

  2. Dynamics of water absorption through superabsorbent polymer

    Science.gov (United States)

    Chang, Sooyoung; Kim, Wonjung

    2017-11-01

    Superabsorbent polymers (SAPs) consist of hydrophilic cross-linked polymer networks that can absorb and retain a great amount of water relative to their own mass, so that they are widely used for disposable diapers and holding soil moisture in agriculture. SAPs are typically available in the form of submillimeter-sized particles, and the water absorption is driven by capillary flows between particles as well as diffusion that entail swelling. Although the control of water absorption of SAPs is important in engineering applications, but the dynamics of water absorption in SAP particles has not been fully understood. We examine the dynamics of the water absorption of sodium polyacrylate, one of the most common SAP. We experimentally measured the water absorption of sodium polyacrylate particles in one-dimensional confined channel. The water flows through the particles were analyzed by capillarity dominant at the early stage and by diffusion involving volume expansion critical at a later stage. The results provide a quantitative basis of the hydrodynamic analysis of the water flow through SAP particles from a macroscopic point of view, facilitating the prediction of water uptake of SAPs in hygienic and agricultural applications. This work was supported by the National Research Foundation of Korea (NRF) Grant funded by the Korea government (MSIP) (No.2015R1A2A2A04006181).

  3. Absorption and initial metabolism of 75Se-l-selenomethionine

    DEFF Research Database (Denmark)

    Grosse Ruse, Mareile; Søndergaard, Lasse R.; Ditlevsen, Susanne

    2015-01-01

    Selenomethionine (SeMet) is an important organic nutritional source of Se, but the uptake and metabolism of SeMet are poorly characterised in humans. Dynamic gamma camera images of the abdominal region were acquired from eight healthy young men after the ingestion of radioactive 75Se-l-SeMet (75Se...... to the plasma and 0·267 h–1 from the stomach to the plasma. The delay in the liver was 0·714 h. Gamma camera imaging provides data for use in compartmental modelling of 75Se-SeMet absorption and metabolism in humans. In clinical settings, the obtained rate constants and the delay in the liver may be useful...

  4. Diet effects on glucose absorption in the small intestine of neonatal calves: importance of intestinal mucosal growth, lactase activity, and glucose transporters.

    Science.gov (United States)

    Steinhoff-Wagner, Julia; Zitnan, Rudolf; Schönhusen, Ulrike; Pfannkuche, Helga; Hudakova, Monika; Metges, Cornelia C; Hammon, Harald M

    2014-10-01

    Colostrum (C) feeding in neonatal calves improves glucose status and stimulates intestinal absorptive capacity, leading to greater glucose absorption when compared with milk-based formula feeding. In this study, diet effects on gut growth, lactase activity, and glucose transporters were investigated in several gut segments of the small intestine. Fourteen male German Holstein calves received either C of milkings 1, 3, and 5 (d 1, 2, and 3 in milk) or respective formulas (F) twice daily from d 1 to d 3 after birth. Nutrient content, and especially lactose content, of C and respective F were the same. On d 4, calves were fed C of milking 5 or respective F and calves were slaughtered 2h after feeding. Tissue samples from duodenum and proximal, mid-, and distal jejunum were taken to measure villus size and crypt depth, mucosa and brush border membrane vesicles (BBMV) were taken to determine protein content, and mRNA expression and activity of lactase and mRNA expression of sodium-dependent glucose co-transporter-1 (SGLT1) and facilitative glucose transporter (GLUT2) were determined from mucosal tissue. Additionally, protein expression of SGLT1 in BBMV and GLUT2 in crude mucosal membranes and BBMV were determined, as well as immunochemically localized GLUT2 in the intestinal mucosa. Villus circumference, area, and height were greater, whereas crypt depth was smaller in C than in F. Lactase activity tended to be greater in C than in F. Protein expression of SGLT1 was greater in F than in C. Parameters of villus size, lactase activity, SGLT1 protein expression, as well as apical and basolateral GLUT2 localization in the enterocytes differed among gut segments. In conclusion, C feeding, when compared with F feeding, enhances glucose absorption in neonatal calves primarily by stimulating mucosal growth and increasing absorptive capacity in the small intestine, but not by stimulating abundance of intestinal glucose transporters. Copyright © 2014 American Dairy Science

  5. Impact of diet on human intestinal microbiota and health.

    Science.gov (United States)

    Salonen, Anne; de Vos, Willem M

    2014-01-01

    Our intestinal microbiota is involved in the breakdown and bioconversion of dietary and host components that are not degraded and taken up by our own digestive system. The end products generated by our microbiota fuel our enterocytes and support growth but also have signaling functions that generate systemic immune and metabolic responses. Due to the immense metabolic capacity of the intestinal microbiota and its relatively high plasticity, there is great interest in identifying dietary approaches that allow intentional and predictable modulation of the microbiota. In this article, we review the current insights on dietary influence on the human intestinal microbiota based on recent high-throughput molecular studies and interconnections with health. We focus especially on the emerging data that identify the amount and type of dietary fat as significant modulators of the colonic microbiota and its metabolic output.

  6. Selective gas absorption by ionic liquids

    DEFF Research Database (Denmark)

    Shunmugavel, Saravanamurugan; Kegnæs, Søren; Due-Hansen, Johannes

    2010-01-01

    Reversible absorption performance for the flue gas components CO 2, NO and SO2 has been tested for several different ionic liquids (ILs) at different temperatures and flue gas compositions. Furthermore, different porous, high surface area carriers have been applied as supports for the ionic liquids...... to obtain Supported Ionic Liquid-Phase (SILP) absorber materials. The use of solid SILP absorbers with selected ILs were found to significantly improve the absorption capacity and sorption dynamics at low flue gas concentration, thus making the applicability of ILs viable in technical, continuous flow...... processes for flue gas cleaning. The results show that CO 2, NO and SO2 can be reversible and selective absorbed using different ILs and that Supported Ionic Liquid-Phase (SILP) absorbers are promising materials for industrial flue gas cleaning. Absorption/desorption dynamics can be tuned by temperatures...

  7. Nanofibrous membrane-based absorption refrigeration system

    Energy Technology Data Exchange (ETDEWEB)

    Isfahani, RN; Sampath, K; Moghaddam, S

    2013-12-01

    This paper presents a study on the efficacy of highly porous nanofibrous membranes for application in membrane-based absorbers and desorbers. Permeability studies showed that membranes with a pore size greater than about one micron have a sufficient permeability for application in the absorber heat exchanger. Membranes with smaller pores were found to be adequate for the desorber heat exchanger. The membranes were implemented in experimental membrane-based absorber and desorber modules and successfully tested. Parametric studies were conducted on both absorber and desorber processes. Studies on the absorption process were focused on the effects of water vapor pressure, cooling water temperature, and the solution velocity on the absorption rate. Desorption studies were conducted on the effects of wall temperature, vapor and solution pressures, and the solution velocity on the desorption rate. Significantly higher absorption and desorption rates than in the falling film absorbers and desorbers were achieved. Published by Elsevier Ltd.

  8. EMPLOYMENT ABSORPTION IN MANUFACTURING INDUSTRY: YOGYAKARTA CASE

    Directory of Open Access Journals (Sweden)

    Aurora Indra Putri

    2011-09-01

    Full Text Available Unemployment has been a main problem in economic development, especially in developing countries. Unemployment stems from the inability of the economy to absorb the growing labor force. This paper investigates factors influencing absorbtion of labor in Yogyakarta manufacturing industries. Variables hypothesized to affect the absorbtion are wage, labor productivity, non-wage spending, and output of production. It collects data from Indonesia Centre Bureau of Statistics, and uses panel data regression, namely common effect approach, to estimate the model. Employing Eviews software package, it finds that wage, labor productivity, and output production significantly influence labor absorption. However, non-wage spending does not significantly influence the absorption.Keywords: Labor absorption, wage, labor productivity, non-wage spendingJEL classification numbers: J01, J23, J24

  9. Metamaterial with electromagnetic transparency under multiband absorptions

    Science.gov (United States)

    Zhang, Xu; Qi, Limei

    2017-02-01

    We propose a metal-dielectric-metal (MDM) metamaterial that has an electromagnetic (EM) transparency spectrum under multiband absorptions in the C and the X bands. The ground continuous metal film used in the conventional metamaterial absorber (MA) is replaced by a structured ground plane (SGP) in our design. The band-pass properties of the front patterned metal film and the SGP determine the EM transparency spectrum, while the magnetic and the electric resonances in the MDM structure contribute to the multiband absorptions. Due to the symmetric structure of the unit cell, the absorption bands and the EM transparency spectrum of the metamaterial have the property of polarization independency. Despite the normal incidence, the metamaterial can also be used for non-normal incidence.

  10. Absorption of Soluble Gases by Atmospheric Nanoaerosols

    CERN Document Server

    Elperin, Tov; Krasovitov, Boris; Lushnikov, Alexey

    2012-01-01

    We investigate mass transfer during absorption of atmospheric trace soluble gases by a single droplet whose size is comparable to the molecular mean free path in air at normal conditions. It is assumed that the trace reactant diffuses to the droplet surface and then reacts with the substances inside the droplet according to the first order rate law. Our analysis applies a flux-matching theory of transport processes in gases and assumes constant thermophysical properties of the gases and liquids. We derive an integral equation of Volterra type for the transient molecular flux density to a liquid droplet and solve it numerically. Numerical calculations are performed for absorption of sulfur dioxide (SO2), dinitrogen trioxide (N2O3) and chlorine (Cl2) by liquid nanoaerosols accompanied by chemical dissociation reaction. It is shown that during gas absorption by nanoaerosols the kinetic effects play significant role, and neglecting kinetic effects leads to significant overestimation of the soluble gas flux into a...

  11. Plasmon absorption modulator systems and methods

    Science.gov (United States)

    Kekatpure, Rohan Deodatta; Davids, Paul

    2014-07-15

    Plasmon absorption modulator systems and methods are disclosed. A plasmon absorption modulator system includes a semiconductor substrate, a plurality of quantum well layers stacked on a top surface of the semiconductor substrate, and a metal layer formed on a top surface of the stack of quantum well layers. A method for modulating plasmonic current includes enabling propagation of the plasmonic current along a metal layer, and applying a voltage across the stack of quantum well layers to cause absorption of a portion of energy of the plasmonic current by the stack of quantum well layers. A metamaterial switching system includes a semiconductor substrate, a plurality of quantum well layers stacked on a top surface of the semiconductor substrate, and at least one metamaterial structure formed on a top surface of the stack of quantum well layers.

  12. Anomalous water absorption in porous materials

    CERN Document Server

    Lockington, D A

    2003-01-01

    The absorption of fluid by unsaturated, rigid porous materials may be characterized by the sorptivity. This is a simple parameter to determine and is increasingly being used as a measure of a material's resistance to exposure to fluids (especially moisture and reactive solutes) in aggressive environments. The complete isothermal absorption process is described by a nonlinear diffusion equation, with the hydraulic diffusivity being a strongly nonlinear function of the degree of saturation of the material. This diffusivity can be estimated from the sorptivity test. In a typical test the cumulative absorption is proportional to the square root of time. However, a number of researchers have observed deviation from this behaviour when the infiltrating fluid is water and there is some potential for chemo-mechanical interaction with the material. In that case the current interpretation of the test and estimation of the hydraulic diffusivity is no longer appropriate. Kuentz and Lavallee (2001) discuss the anomalous b...

  13. Investigation of two-photon absorption induced excited state absorption in a fluorenyl-based chromophore.

    Science.gov (United States)

    Li, Changwei; Yang, Kun; Feng, Yan; Su, Xinyan; Yang, Junyi; Jin, Xiao; Shui, Min; Wang, Yuxiao; Zhang, Xueru; Song, Yinglin; Xu, Hongyao

    2009-12-03

    Two-photon absorption induced excited state absorption in the solution of a new fluorenyl-based chromophore is investigated by a time-resolved pump-probe technique using femtosecond pulses. With the help of an additional femtosecond open-aperture Z-scan technique, numerical simulations based on a three-energy level model are used to interpret the experimental results, and we determine the nonlinear optical parameters of this new chromophore uniquely. Large two-photon absorption cross section and excited state absorption cross section for singlet excited state are obtained, indicating a good candidate for optical limiting devices. Moreover, the influence of two-beam coupling induced energy transfer in neat N,N'-dimethylformamide solvent is also considered, although this effect is strongly restrained by the instantaneous two-photon absorption.

  14. Review on absorption technology with emphasis on small capacity absorption machines

    Directory of Open Access Journals (Sweden)

    Labus Jerko M.

    2013-01-01

    Full Text Available The aim of this paper is to review the past achievements in the field of absorption systems, their potential and possible directions for future development. Various types of absorption systems and research on working fluids are discussed in detail. Among various applications, solar cooling and combined cooling, heating and power (CCHP are identified as two most promising applications for further development of absorption machines. Under the same framework, special attention is given to the small capacity absorption machines and their current status at the market. Although this technology looks promising, it is still in development and many issues are open. With respect to that fact, this paper covers all the relevant aspects for further development of small capacity absorption machines.

  15. Equivalent sound absorption area in a rectangular reverberant room (Sabine's sound absorption factor)

    Science.gov (United States)

    Tohyama, M.

    1986-07-01

    The equivalent sound absorption area in a rectangular reverberant room can be derived from the initial first and second derivatives (initial decay rate of the time derivative) of the ensemble and space-averaged sound energy decay curve. At low frequency bands, how to estimate the equivalent sound absorption area from the reverberation time has not been theoretically interpreted. This is because the decay curve is not linear in logarithmic scales. The formula for the absorption area derived here, however, does not contain the reverberation time. It shows the theoretical relation between the absorption area and the initial slopes of the decay curve. The equivalent absorption area and averaged damping constants can be estimated theoretically according to the relation derived here for low frequency bands.

  16. Aerosol optical absorption measurements with photoacoustic spectroscopy

    Science.gov (United States)

    Liu, Kun; Wang, Lei; Liu, Qiang; Wang, Guishi; Tan, Tu; Zhang, Weijun; Chen, Weidong; Gao, Xiaoming

    2015-04-01

    Many parameters related to radiative forcing in climate research are known only with large uncertainties. And one of the largest uncertainties in global radiative forcing is the contribution from aerosols. Aerosols can scatter or absorb the electromagnetic radiation, thus may have negative or positive effects on the radiative forcing of the atmosphere, respectively [1]. And the magnitude of the effect is directly related to the quantity of light absorbed by aerosols [2,3]. Thus, sensitivity and precision measurement of aerosol optical absorption is crucial for climate research. Photoacoustic spectroscopy (PAS) is commonly recognized as one of the best candidates to measure the light absorption of aerosols [4]. A PAS based sensor for aerosol optical absorption measurement was developed. A 532 nm semiconductor laser with an effective power of 160 mW was used as a light source of the PAS sensor. The PAS sensor was calibrated by using known concentration NO2. The minimum detectable optical absorption coefficient (OAC) of aerosol was determined to be 1 Mm-1. 24 hours continues measurement of OAC of aerosol in the ambient air was carried out. And a novel three wavelength PAS aerosol OAC sensor is in development for analysis of aerosol wavelength-dependent absorption Angstrom coefficient. Reference [1] U. Lohmann and J. Feichter, Global indirect aerosol effects: a review, Atmos. Chem. Phys. 5, 715-737 (2005) [2] M. Z. Jacobson, Strong radiative heating due to the mixing state of black carbon in atmospheric aerosols, Nature 409, 695-697 (2001) [3] V. Ramanathan and G. Carmichae, Global and regional climate changes due to black carbon, nature geoscience 1, 221-227 (2008) [4] W.P Arnott, H. Moosmuller, C. F. Rogers, T. Jin, and R. Bruch, Photoacoustic spectrometer for measuring light absorption by aerosol: instrument description. Atmos. Environ. 33, 2845-2852 (1999).

  17. Enhanced absorption cycle computer model. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Grossman, G.; Wilk, M. [Technion-Israel Inst. of Tech., Haifa (Israel). Faculty of Mechanical Engineering

    1993-09-01

    Absorption heat pumps have received renewed and increasing attention in the past two decades. The rising cost of electricity has made the particular features of this heat-powered cycle attractive for both residential and industrial applications. Solar-powered absorption chillers, gas-fired domestic heat pumps, and waste-heat-powered industrial temperatures boosters are a few of the applications recently subjected to intensive research and development. The absorption heat pump research community has begun to search for both advanced cycles in various multistage configurations and new working fluid combinations with potential for enhanced performance and reliability. The development of working absorptions systems has created a need for reliable and effective system simulations. A computer code has been developed for simulation of absorption systems at steady state in a flexible and modular form, making it possible to investigate various cycle configurations with different working fluids. The code is based on unit subroutines containing the governing equations for the system`s components and property subroutines containing thermodynamic properties of the working fluids. The user conveys to the computer an image of his cycle by specifying the different subunits and their interconnections. Based on this information, the program calculates the temperature, flow rate, concentration, pressure, and vapor fraction at each state point in the system, and the heat duty at each unit, from which the coefficient of performance (COP) may be determined. This report describes the code and its operation, including improvements introduced into the present version. Simulation results are described for LiBr-H{sub 2}O triple-effect cycles, LiCl-H{sub 2}O solar-powered open absorption cycles, and NH{sub 3}-H{sub 2}O single-effect and generator-absorber heat exchange cycles. An appendix contains the User`s Manual.

  18. Rock physics investigation of seismic wave absorption in reservoir ...

    African Journals Online (AJOL)

    The difference between modulus estimated at high and low frequencies is translated to the coefficient of absorption (or inverse quality factor). Absorption estimated at ... interpret for fluid units. Information about seismic absorption can also be used, by means of absorption compensation, to enhance seismic data resolution.

  19. Assessment system for dioxin absorption in the small intestine and prevention of its absorption by food factors.

    Science.gov (United States)

    Natsume, Yayoi; Satsu, Hideo; Kitamura, Kazushige; Okamoto, Naoto; Shimizu, Makoto

    2004-01-01

    It has been reported that 90% of the amount of dioxin in the whole body is absorbed orally with food. However, a concise and simple system to assess dioxin absorption in the small intestine has not yet been established. The present study reports a new in vitro assessment system for this purpose. A stable dioxin-responsive cell line was established by introducing a plasmid that incorporates a xenobiotic-responsive element upstream of the luciferase gene into human hepatic HepG2 genomic DNA. Dioxin was added to the apical side of differentiated human intestinal epithelial Caco-2 cell monolayers that had been cultured on a semipermeable membrane, and the basal medium was recovered after an appropriate incubation time. To the recovered medium was added dioxin-responsive HepG2, and a luciferase assay was performed. The established stable cell line clearly showed dose-and time-dependent response to dioxin. When a food factor such as chlorophyll, which has been reported to increase dioxin excretion in in vivo studies, was added with dioxin, a significant decrease in dioxin permeability to the Caco-2 monolayer was observed. This assessment system would be useful to search for those food factors that could prevent dioxin absorption in the small intestine.

  20. ABRASIVE ABSORPTION STUDY IN AWJ CUTTING

    Directory of Open Access Journals (Sweden)

    Bogdan BARABAŞ

    2016-11-01

    Full Text Available This paper studies the forming process of the hydro abrasive jet and the factors that determine its behaviour after leaving the nozzle until the moment of impact with the piece, in order to obtain an optimized configuration of the processing. The objectives are those of obtaining optimal surfaces in terms of quality, increased productivity and reduced costs. The paper specifies the model of the jet forming through air and abrasive absorption. The obtained results have confirmed the importance of exactly configuring the abrasive quantity in the jet through modifying the size of the abrasive grains and the attraction force required for their absorption.

  1. Porosity and liquid absorption of cement paste

    DEFF Research Database (Denmark)

    Krus, M.; Hansen, Kurt Kielsgaard; Kunzel, H. M.

    1997-01-01

    be a slowing-down effect which is related to water because the absorption of organic liquids, such as hexane, is quite normal. Measurements of the porosity of hardened cement paste determined by helium pycnometry and water saturation show that water molecules can enter spaces in the microstructure which...... are not accessible to the smaller helium atoms. Considering the results of dilatation tests both before and after water and hexane saturation, it seems possible that a contraction of capillary pores due to moisture-related swelling of the cement gel leads to the non-linear water absorption over the square root...

  2. Absorptive routines and international patent performance

    Directory of Open Access Journals (Sweden)

    Fernando E. García-Muiña

    2017-04-01

    We enrich the treatment of the absorptive capacity phases including the moderating effects between routines associated to the traditional potential-realized absorptive capacities. Taking into account external knowledge search strategies, the deeper external relationships, the better transference and appropriation of specific external knowledge. Nevertheless, when the moderating role of assimilation is included, cooperation agreements appear as the most efficient source of external knowledge. Finally, we show that technological tools let firms store and structure the information making easier its use for international patenting. This positive effect is reinforced in the presence of exploitation routines, since technological knowledge will better fit to the industry's key factors of success.

  3. Spectral line absorption measurement using optical cavities.

    Science.gov (United States)

    Blanaru, D. L.

    1973-01-01

    A simple technique using a conventional gas laser with spherical mirrors having identical radii of curvature in the nonoscillating regime for spectral line absorption measurements is described and applications for laser work are suggested. The theory of the measurement carried out in the geometrical optical approach for Doppler-broadened lines was checked experimentally and conditions are specified for which measurement inaccuracies of the order of 1% for the peak value of the line absorption coefficient can be obtained. Since the device provides a fine adjustment of the cavity losses, formation of the diffraction modes could be observed in the preoscillating regime of the optical cavity.

  4. Unveiling the Microfoundations of Absorptive Capacity

    DEFF Research Database (Denmark)

    Distel, Andreas Philipp

    2017-01-01

    explores the multilevel antecedents of absorptive capacity using survey data gathered from 342 informants at different levels of analysis in 106 medical technology firms. Multilevel structural equation modeling analyses indicate that formal and informal integration mechanisms are positively related......Although the concept of absorptive capacity has gained wide acceptance in the literature, our understanding of the origins of a firm’s ability to absorb and leverage new knowledge is limited. Drawing on Coleman’s (1990) bathtub framework for macro-micro-macro-relations in social science, this study...

  5. Achromatic THz absorption of conductive nanofilms

    Directory of Open Access Journals (Sweden)

    Qiang Yin

    2015-10-01

    Full Text Available According to the theory, an ultrathin conductive film can achromatically dissipate electromagnetic waves with frequency ranging from radio to terahertz. A moderate absorption effect, which gives rise to a maximal absorbance of 50%, can be found if an impedance matching condition is satisfied. We have experimentally demonstrated the frequency-irrelevant, maximal absorption by employing a conductive nanofilm and launching terahertz waves at Brewster angle when the sheet (square resistance of the film meets the impedance matching condition. In the entire terahertz spectral range covered by our experiments, the frequency-independent optical properties were consistent with the theoretical calculations.

  6. Absorption properties of micellar lipid metabolites into Caco2 cells.

    Science.gov (United States)

    Tsuzuki, Wakako

    2007-07-01

    To elucidate the absorption characteristics of dietary lipids in the human intestine, we investigated the cellular uptake of lipid metabolites using a differential monolayer of the Caco2 cells. As lipid metabolites, several free fatty acids and 2-monoacylglycerols, were formed a mixed micelle by bile salts and lysophospholipids and they were supplied to the Caco2 cells. To estimate the effect of the mixed micelles on the permeability of cells' membranes during incubation with the mixed micelles, the transepitherial electrical resistance (TEER) value was monitored, and no pronounced changes of TEER was detected. This suggested that mixed micelles did not affect their cellular properties of the barrier measured by TEER. The lipid metabolites transferred from the mixed micelle into the Caco2 cells were determined quantitatively by an enzymatic colorimetric method and were done by thin layer chromatography (TLC) for a species of acylglycerols. These highly sensitive methods enabled us to monitor the transepithelial transports of various kinds of non-isotope-labeled various lipid metabolites. Newly re-synthesized triacylglycerols were accumulated in Caco2 cells after 30 min incubation with the mixed micelles, and their amounts increased gradually for 4 h. The secretion of re-esterified triacylglycerols into a basolateral medium from the Caco2 cells began at 2 h after the mixed micelles were added to the apical medium. The intake of external lipid metabolites by the Caco2 cells were evaluated by an initial 2-h incubation with the mixed micelles. For example, 2-monomyristin and 2-monopalmitin were more rapidly transferred into the Caco2 cells from the mixed micelles than 2-monocaprin was. On the other hand, the absorption rates of capric acid, lauric acid and myristic acid by the cells were larger than those of stearic acid and oleic acid. It revealed that the side-chain structure of these lipid metabolites affected their absorption by the Caco2 cells. The results of this

  7. Evaluating the New Automatic Method for the Analysis of Absorption Spectra Using Synthetic Spectra

    Directory of Open Access Journals (Sweden)

    Matthew B. Bainbridge

    2017-04-01

    Full Text Available We recently presented a new “artificial intelligence” method for the analysis of high-resolution absorption spectra (Bainbridge and Webb, Mon. Not. R. Astron. Soc. 2017, doi:10.1093/mnras/stx179. This new method unifies three established numerical methods: a genetic algorithm (GVPFIT; non-linear least-squares optimisation with parameter constraints (VPFIT; and Bayesian Model Averaging (BMA. In this work, we investigate the performance of GVPFIT and BMA over a broad range of velocity structures using synthetic spectra. We found that this new method recovers the velocity structures of the absorption systems and accurately estimates variation in the fine structure constant. Studies such as this one are required to evaluate this new method before it can be applied to the analysis of large sets of absorption spectra. This is the first time that a sample of synthetic spectra has been utilised to investigate the analysis of absorption spectra. Probing the variation of nature’s fundamental constants (such as the fine structure constant, through the analysis of absorption spectra, is one of the most direct ways of testing the universality of physical laws. This “artificial intelligence” method provides a way to avoid the main limiting factor, i.e., human interaction, in the analysis of absorption spectra.

  8. Addition of milk does not affect the absorption of flavonols from tea in man

    NARCIS (Netherlands)

    Hollman, P.C.H.; Hof, van het K.H.; Tijburg, L.B.M.; Katan, M.B.

    2001-01-01

    Tea is a major source of flavonols, a subclass of antioxidant flavonoids present in plant foods which potentially are beneficial to human health. Milk added to tea, a frequent habit in the United Kingdom, could inhibit absorption of tea flavonoids, because proteins can bind flavonoids effectively.

  9. Relationship between subcutaneous blood flow and absorption of lente type insulin

    DEFF Research Database (Denmark)

    Hildebrant, P; Mehlsen, J; Birch, K

    1987-01-01

    To study the relationship between the absorption of intermediate acting insulin and the local subcutaneous blood flow (SBF) 8 diabetic patients were given subcutaneous injections of 125I labeled human lente type insulin and 133Xenon in the abdominal wall. External measurements of the tracer...

  10. In vitro System for Assessing Dioxin Absorption by Intestinal Epithelial Cells and for Preventing this Absorption by Food Substances

    OpenAIRE

    Natsume, Yayoi; Satsu, Hideo; Hamada, Mika; Kitamura, Kazushige; Okamoto, Naoto; Shimizu, Makoto

    2005-01-01

    A system for assessing intestinal dioxin absorption was established by applying a Caco-2 cell monolayer and stable dioxin-responsive cell line. The stable dioxin-responsive cell line was established by introducing a plasmid incorporating the human CYP1A1 promoter into human hepatic HepG2 genomic DNA upstream of the luciferase gene. 2,3,7,8-Tetrachlorodibenzodioxin (TCDD) was added to the apical side of differentiated human intestinal epithelial Caco-2 cell monolayers that had been cultured on...

  11. Water absorption characteristic of interlocking compressed earth brick units

    Science.gov (United States)

    Bakar, B. H. Abu; Saari, S.; Surip, N. A.

    2017-10-01

    This study aims to investigate the water absorption characteristic of interlocking compressed earth brick (ICEB) units. Apart from compressive strength, water absorption is an important property in masonry. This property can affect the quality of the brick itself and the bond strength between the brick and mortar in masonry structures and can result in reducing its strength properties. The units were tested for 24 h water absorption and 5 h boiling water absorption. A total of 170 ICEB units from four ICEB types underwent both tests. For the 24 h water absorption, the ICEB units were dried in the oven for 24 h and then cooled before being weighed. Thereafter, each brick was immersed in water for 24 h and weighed. The same specimens used for the 24 h water absorption test were re-used for the 5 h boiling water absorption test. After completing the 24 h water absorption test, the brick was boiled for 5-hours and weighed. The highest water absorption for the ICEBs in the 24-hour water absorption and 5 h boiling water absorption tests are 15.09% and 17.18%, respectively. The half brick has the highest water absorption (15.87%), whereas the beam brick has the lowest (13.20%). The water absorption of an ICEB unit is higher than that of normal bricks, although the water absorption of the former remains below the maximum rate of the brick water absorption (21%).

  12. Examination of the Measurement of Absorption Using the Reverberant Room Method for Highly Absorptive Acoustic Foam

    Science.gov (United States)

    Hughes, William O.; McNelis, Anne M.; Chris Nottoli; Eric Wolfram

    2015-01-01

    The absorption coefficient for material specimens are needed to quantify the expected acoustic performance of that material in its actual usage and environment. The ASTM C423-09a standard, "Standard Test Method for Sound Absorption and Sound Absorption Coefficients by the Reverberant Room Method" is often used to measure the absorption coefficient of material test specimens. This method has its basics in the Sabine formula. Although widely used, the interpretation of these measurements are a topic of interest. For example, in certain cases the measured Sabine absorption coefficients are greater than 1.0 for highly absorptive materials. This is often attributed to the diffraction edge effect phenomenon. An investigative test program to measure the absorption properties of highly absorbent melamine foam has been performed at the Riverbank Acoustical Laboratories. This paper will present and discuss the test results relating to the effect of the test materials' surface area, thickness and edge sealing conditions. A follow-on paper is envisioned that will present and discuss the results relating to the spacing between multiple piece specimens, and the mounting condition of the test specimen.

  13. Realistic absorption coefficient of ultrathin films

    Science.gov (United States)

    Cesaria, M.; Caricato, A. P.; Martino, M.

    2012-10-01

    Both a theoretical algorithm and an experimental procedure are discussed of a new route to determine the absorption/scattering properties of thin films deposited on transparent substrates. Notably, the non-measurable contribution of the film-substrate interface is inherently accounted for. While the experimental procedure exploits only measurable spectra combined according to a very simple algorithm, the theoretical derivation does not require numerical handling of the acquired spectra or any assumption on the film homogeneity and substrate thickness. The film absorption response is estimated by subtracting the measured absorption spectrum of the bare substrate from that of the film on the substrate structure but in a non-straightforward way. In fact, an assumption about the absorption profile of the overall structure is introduced and a corrective factor accounting for the relative film-to-substrate thickness. The method is tested on films of a well known material (ITO) as a function of the film structural quality and influence of the film-substrate interface, both deliberately changed by thickness tuning and doping. Results are found fully consistent with information obtained by standard optical analysis and band gap values reported in the literature. Additionally, comparison with a conventional method demonstrates that our route is generally more accurate even if particularly suited for very thin films.

  14. Absorptive coating for aluminum solar panels

    Science.gov (United States)

    Desmet, D.; Jason, A.; Parr, A.

    1979-01-01

    Method for coating forming coating of copper oxide from copper component of sheet aluminum/copper alloy provides strong durable solar heat collector panels. Copper oxide coating has solar absorption characteristics similar to black chrome and is much simpler and less costly to produce.

  15. Simple parametrization of photon mass energy absorption ...

    Indian Academy of Sciences (India)

    Abstract. In this paper, we provide polynomial coefficients and a semi-empirical relation using which one can derive photon mass energy absorption coefficient of any H-, C-, N-,. O-based sample of biological interest containing any other elements in the atomic number range 2–40 and energy range 200–1500 keV.

  16. Experimental methodology for obtaining sound absorption coefficients

    Directory of Open Access Journals (Sweden)

    Carlos A. Macía M

    2011-07-01

    Full Text Available Objective: the authors propose a new methodology for estimating sound absorption coefficients using genetic algorithms. Methodology: sound waves are generated and conducted along a rectangular silencer. The waves are then attenuated by the absorbing material covering the silencer’s walls. The attenuated sound pressure level is used in a genetic algorithm-based search to find the parameters of the proposed attenuation expressions that include geometric factors, the wavelength and the absorption coefficient. Results: a variety of adjusted mathematical models were found that make it possible to estimate the absorption coefficients based on the characteristics of a rectangular silencer used for measuring the attenuation of the noise that passes through it. Conclusions: this methodology makes it possible to obtain the absorption coefficients of new materials in a cheap and simple manner. Although these coefficients might be slightly different from those obtained through other methodologies, they provide solutions within the engineering accuracy ranges that are used for designing noise control systems.

  17. The Absorption Refrigerator as a Thermal Transformer

    Science.gov (United States)

    Herrmann, F.

    2009-01-01

    The absorption refrigerator can be considered a thermal transformer, that is, a device that is analogous to the electric transformer. The analogy is based on the correspondence between the extensive quantities, entropy and electric charge and the intensive variables, temperature and electric potential. (Contains 1 footnote and 6 figures.)

  18. Resonant Light Absorption by Semiconductor Quantum Dots

    Directory of Open Access Journals (Sweden)

    I. G. Lang

    2009-01-01

    calculated in the case of a resonance with an exciton Γ6×Γ7 in cubical crystals of class. The interference of stimulating and induced electric and magnetic fields is taken into account. The cross-section of light absorption is proportional to the exciton nonradiative damping .

  19. Absorption heat pump cycles with NH

    NARCIS (Netherlands)

    Wang, M.; Infante Ferreira, C.A.

    2017-01-01

    Ionic liquids (ILs), as novel absorbents, draw considerable attention for their potential roles in replacing water or LiBr aqueous solutions in conventional NH3/H2O or H2O/LiBr absorption refrigeration or heat pump cycles. In this paper, performances of 9

  20. A method optimization study for atomic absorption ...

    African Journals Online (AJOL)

    A sensitive, reliable and relative fast method has been developed for the determination of total zinc in insulin by atomic absorption spectrophotometer. This designed study was used to optimize the procedures for the existing methods. Spectrograms of both standard and sample solutions of zinc were recorded by measuring ...